WorldWideScience

Sample records for human disease transmission

  1. Human prion diseases: surgical lessons learned from iatrogenic prion transmission.

    Science.gov (United States)

    Bonda, David J; Manjila, Sunil; Mehndiratta, Prachi; Khan, Fahd; Miller, Benjamin R; Onwuzulike, Kaine; Puoti, Gianfranco; Cohen, Mark L; Schonberger, Lawrence B; Cali, Ignazio

    2016-07-01

    The human prion diseases, or transmissible spongiform encephalopathies, have captivated our imaginations since their discovery in the Fore linguistic group in Papua New Guinea in the 1950s. The mysterious and poorly understood "infectious protein" has become somewhat of a household name in many regions across the globe. From bovine spongiform encephalopathy (BSE), commonly identified as mad cow disease, to endocannibalism, media outlets have capitalized on these devastatingly fatal neurological conditions. Interestingly, since their discovery, there have been more than 492 incidents of iatrogenic transmission of prion diseases, largely resulting from prion-contaminated growth hormone and dura mater grafts. Although fewer than 9 cases of probable iatrogenic neurosurgical cases of Creutzfeldt-Jakob disease (CJD) have been reported worldwide, the likelihood of some missed cases and the potential for prion transmission by neurosurgery create considerable concern. Laboratory studies indicate that standard decontamination and sterilization procedures may be insufficient to completely remove infectivity from prion-contaminated instruments. In this unfortunate event, the instruments may transmit the prion disease to others. Much caution therefore should be taken in the absence of strong evidence against the presence of a prion disease in a neurosurgical patient. While the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) have devised risk assessment and decontamination protocols for the prevention of iatrogenic transmission of the prion diseases, incidents of possible exposure to prions have unfortunately occurred in the United States. In this article, the authors outline the historical discoveries that led from kuru to the identification and isolation of the pathological prion proteins in addition to providing a brief description of human prion diseases and iatrogenic forms of CJD, a brief history of prion disease nosocomial transmission

  2. Quantifying human-environment interactions using videography in the context of infectious disease transmission.

    Science.gov (United States)

    Julian, Timothy R; Bustos, Carla; Kwong, Laura H; Badilla, Alejandro D; Lee, Julia; Bischel, Heather N; Canales, Robert A

    2018-05-08

    Quantitative data on human-environment interactions are needed to fully understand infectious disease transmission processes and conduct accurate risk assessments. Interaction events occur during an individual's movement through, and contact with, the environment, and can be quantified using diverse methodologies. Methods that utilize videography, coupled with specialized software, can provide a permanent record of events, collect detailed interactions in high resolution, be reviewed for accuracy, capture events difficult to observe in real-time, and gather multiple concurrent phenomena. In the accompanying video, the use of specialized software to capture humanenvironment interactions for human exposure and disease transmission is highlighted. Use of videography, combined with specialized software, allows for the collection of accurate quantitative representations of human-environment interactions in high resolution. Two specialized programs include the Virtual Timing Device for the Personal Computer, which collects sequential microlevel activity time series of contact events and interactions, and LiveTrak, which is optimized to facilitate annotation of events in real-time. Opportunities to annotate behaviors at high resolution using these tools are promising, permitting detailed records that can be summarized to gain information on infectious disease transmission and incorporated into more complex models of human exposure and risk.

  3. Quantifying human-environment interactions using videography in the context of infectious disease transmission

    Directory of Open Access Journals (Sweden)

    Timothy R. Julian

    2018-05-01

    Full Text Available Quantitative data on human-environment interactions are needed to fully understand infectious disease transmission processes and conduct accurate risk assessments. Interaction events occur during an individual’s movement through, and contact with, the environment, and can be quantified using diverse methodologies. Methods that utilize videography, coupled with specialized software, can provide a permanent record of events, collect detailed interactions in high resolution, be reviewed for accuracy, capture events difficult to observe in real-time, and gather multiple concurrent phenomena. In the accompanying video, the use of specialized software to capture humanenvironment interactions for human exposure and disease transmission is highlighted. Use of videography, combined with specialized software, allows for the collection of accurate quantitative representations of human-environment interactions in high resolution. Two specialized programs include the Virtual Timing Device for the Personal Computer, which collects sequential microlevel activity time series of contact events and interactions, and LiveTrak, which is optimized to facilitate annotation of events in real-time. Opportunities to annotate behaviors at high resolution using these tools are promising, permitting detailed records that can be summarized to gain information on infectious disease transmission and incorporated into more complex models of human exposure and risk.

  4. Chronic wasting disease prions are not transmissible to transgenic mice overexpressing human prion protein.

    Science.gov (United States)

    Sandberg, Malin K; Al-Doujaily, Huda; Sigurdson, Christina J; Glatzel, Markus; O'Malley, Catherine; Powell, Caroline; Asante, Emmanuel A; Linehan, Jacqueline M; Brandner, Sebastian; Wadsworth, Jonathan D F; Collinge, John

    2010-10-01

    Chronic wasting disease (CWD) is a prion disease that affects free-ranging and captive cervids, including mule deer, white-tailed deer, Rocky Mountain elk and moose. CWD-infected cervids have been reported in 14 USA states, two Canadian provinces and in South Korea. The possibility of a zoonotic transmission of CWD prions via diet is of particular concern in North America where hunting of cervids is a popular sport. To investigate the potential public health risks posed by CWD prions, we have investigated whether intracerebral inoculation of brain and spinal cord from CWD-infected mule deer transmits prion infection to transgenic mice overexpressing human prion protein with methionine or valine at polymorphic residue 129. These transgenic mice have been utilized in extensive transmission studies of human and animal prion disease and are susceptible to BSE and vCJD prions, allowing comparison with CWD. Here, we show that these mice proved entirely resistant to infection with mule deer CWD prions arguing that the transmission barrier associated with this prion strain/host combination is greater than that observed with classical BSE prions. However, it is possible that CWD may be caused by multiple prion strains. Further studies will be required to evaluate the transmission properties of distinct cervid prion strains as they are characterized.

  5. Phenotype Variation in Human Immunodeficiency virus Type 1 Transmission and Disease Progression

    Directory of Open Access Journals (Sweden)

    Mariangela Cavarelli

    2009-01-01

    Full Text Available Human immunodeficiency virus type I (HIV-1 infects target cells through interaction with the CD4 molecule and chemokine receptors, mainly CCR5 and CXCR4. Viral isolates can be phenotypically classified based on the co-receptor they utilize to infect target cells. Thus, R5 and X4 virus use respectively CCR5 and CXCR4, whereas R5X4 virus can use either CCR5 or CXCR4. This review describes the central role played by co-receptor expression and usage for HIV-1 cell tropism, transmission and pathogenesis. We discuss various hypotheses proposed to explain the preferential transmission of R5 viruses and the mechanisms driving the change of HIV-1 co-receptor usage in the course of infection. Recent insights in the intrinsic variability of R5 viruses and their role in influencing disease progression in both adults and children are also discussed.

  6. Phenotype variation in human immunodeficiency virus type 1 transmission and disease progression.

    Science.gov (United States)

    Cavarelli, Mariangela; Scarlatti, Gabriella

    2009-01-01

    Human immunodeficiency virus type I (HIV-1) infects target cells through interaction with the CD4 molecule and chemokine receptors, mainly CCR5 and CXCR4. Viral isolates can be phenotypically classified based on the co-receptor they utilize to infect target cells. Thus, R5 and X4 virus use respectively CCR5 and CXCR4, whereas R5X4 virus can use either CCR5 or CXCR4. This review describes the central role played by co-receptor expression and usage for HIV-1 cell tropism, transmission and pathogenesis. We discuss various hypotheses proposed to explain the preferential transmission of R5 viruses and the mechanisms driving the change of HIV-1 co-receptor usage in the course of infection. Recent insights in the intrinsic variability of R5 viruses and their role in influencing disease progression in both adults and children are also discussed.

  7. The improbable transmission of Trypanosoma cruzi to human: the missing link in the dynamics and control of Chagas disease.

    Directory of Open Access Journals (Sweden)

    Pierre Nouvellet

    2013-11-01

    Full Text Available Chagas disease has a major impact on human health in Latin America and is becoming of global concern due to international migrations. Trypanosoma cruzi, the etiological agent of the disease, is one of the rare human parasites transmitted by the feces of its vector, as it is unable to reach the salivary gland of the insect. This stercorarian transmission is notoriously poorly understood, despite its crucial role in the ecology and evolution of the pathogen and the disease. The objective of this study was to quantify the probability of T. cruzi vectorial transmission to humans, and to use such an estimate to predict human prevalence from entomological data. We developed several models of T. cruzi transmission to estimate the probability of transmission from vector to host. Using datasets from the literature, we estimated the probability of transmission per contact with an infected triatomine to be 5.8 × 10(-4 (95%CI: [2.6 ; 11.0] × 10(-4. This estimate was consistent across triatomine species, robust to variations in other parameters, and corresponded to 900-4,000 contacts per case. Our models subsequently allowed predicting human prevalence from vector abundance and infection rate in 7/10 independent datasets covering various triatomine species and epidemiological situations. This low probability of T. cruzi transmission reflected well the complex and unlikely mechanism of transmission via insect feces, and allowed predicting human prevalence from basic entomological data. Although a proof of principle study would now be valuable to validate our models' predictive ability in an even broader range of entomological and ecological settings, our quantitative estimate could allow switching the evaluation of disease risk and vector control program from purely entomological indexes to parasitological measures, as commonly done for other major vector borne diseases. This might lead to different quantitative perspectives as these indexes are well known

  8. Sexual transmission of Lyme disease: challenging the tickborne disease paradigm.

    Science.gov (United States)

    Stricker, Raphael B; Middelveen, Marianne J

    2015-01-01

    Lyme disease caused by the spirochete Borrelia burgdorferi has become a major worldwide epidemic. In this article, we explore the clinical, epidemiological and experimental evidence for sexual transmission of Lyme disease in animal models and humans. Although the likelihood of sexual transmission of the Lyme spirochete remains speculative, the possibility of Lyme disease transmission via intimate human contact merits further study.

  9. Elephant-to-Human Transmission of Tuberculosis

    Centers for Disease Control (CDC) Podcasts

    This podcast reports on the transmission of TB from elephants to humans. Dr. Rendi Murphree, Epidemic Intelligence Service Officer at the Centers for Disease Control and Prevention and Vanderbilt University Visiting Scholar, discusses the recent elephant-to-human transmission of tuberculosis at an elephant refuge in Tennessee.

  10. [Human transmissible subacute spongiform encephalopathy].

    Science.gov (United States)

    Dormont, D

    1994-05-01

    Human transmissible spongiform encephalopathies (TSE) are rare chronic subacute degenerative diseases of the central nervous system (CNS) which include Creutzfeldt-Jakob disease (CJD), Kuru, Gerstmann-Sträussler-Scheinker syndrome (GSS), and Fatal Familial Insomnia (FFI). CJD can be either inherited or sporadic. All these diseases are always fatal. Neuropathological features are mainly constituted of neuronal vacuolisation, neuronal death, gliosis with hyperastrocytosis; plaques might be evidenced in kuru and GSS. Neither inflammatory syndrome nor demyelination is detectable. No virus like structure could be identified reproducibly. Human TSE are transmissible to non human primates and rodents. Iatrogenic CJD have been described after tissue grafting (cornea, dura mater), neurosurgery, electrophysiology investigation, and treatment with pituitary derived gonadotrophins and growth hormone. Molecular biochemistry of the CNS investigation revealed that a host encoded protein, the prion protein (PrP), accumulates proportionally to the infectious titer: this abnormality is the only detectable hallmark in TSE. Infectious fractions contain no detectable specific nucleic acid, and are mainly constituted of PrP under an isoform which resists to proteinase K digestion (PrP-res). The PrP gene (PRNP) is located on chromosome 20 in humans. Several mutations of this gene have been described in all inherited TSE (CJD, GSS, and IFF). No treatment is available today. Agents inducing TSE (TSA) are not known: several authors claim that TSA are only constituted of PrP-res; others support the hypothesis of a conventional agent with a specific genetic information.

  11. Effect of human movement on airborne disease transmission in an airplane cabin: study using numerical modeling and quantitative risk analysis.

    Science.gov (United States)

    Han, Zhuyang; To, Gin Nam Sze; Fu, Sau Chung; Chao, Christopher Yu-Hang; Weng, Wenguo; Huang, Quanyi

    2014-08-06

    Airborne transmission of respiratory infectious disease in indoor environment (e.g. airplane cabin, conference room, hospital, isolated room and inpatient ward) may cause outbreaks of infectious diseases, which may lead to many infection cases and significantly influences on the public health. This issue has received more and more attentions from academics. This work investigates the influence of human movement on the airborne transmission of respiratory infectious diseases in an airplane cabin by using an accurate human model in numerical simulation and comparing the influences of different human movement behaviors on disease transmission. The Eulerian-Lagrangian approach is adopted to simulate the dispersion and deposition of the expiratory aerosols. The dose-response model is used to assess the infection risks of the occupants. The likelihood analysis is performed as a hypothesis test on the input parameters and different human movement pattern assumptions. An in-flight SARS outbreak case is used for investigation. A moving person with different moving speeds is simulated to represent the movement behaviors. A digital human model was used to represent the detailed profile of the occupants, which was obtained by scanning a real thermal manikin using the 3D laser scanning system. The analysis results indicate that human movement can strengthen the downward transport of the aerosols, significantly reduce the overall deposition and removal rate of the suspended aerosols and increase the average infection risk in the cabin. The likelihood estimation result shows that the risk assessment results better fit the outcome of the outbreak case when the movements of the seated passengers are considered. The intake fraction of the moving person is significantly higher than most of the seated passengers. The infection risk distribution in the airplane cabin highly depends on the movement behaviors of the passengers and the index patient. The walking activities of the crew

  12. Chronic wasting disease and atypical forms of bovine spongiform encephalopathy and scrapie are not transmissible to mice expressing wild-type levels of human prion protein.

    Science.gov (United States)

    Wilson, Rona; Plinston, Chris; Hunter, Nora; Casalone, Cristina; Corona, Cristiano; Tagliavini, Fabrizio; Suardi, Silvia; Ruggerone, Margherita; Moda, Fabio; Graziano, Silvia; Sbriccoli, Marco; Cardone, Franco; Pocchiari, Maurizio; Ingrosso, Loredana; Baron, Thierry; Richt, Juergen; Andreoletti, Olivier; Simmons, Marion; Lockey, Richard; Manson, Jean C; Barron, Rona M

    2012-07-01

    The association between bovine spongiform encephalopathy (BSE) and variant Creutzfeldt-Jakob disease (vCJD) has demonstrated that cattle transmissible spongiform encephalopathies (TSEs) can pose a risk to human health and raises the possibility that other ruminant TSEs may be transmissible to humans. In recent years, several novel TSEs in sheep, cattle and deer have been described and the risk posed to humans by these agents is currently unknown. In this study, we inoculated two forms of atypical BSE (BASE and H-type BSE), a chronic wasting disease (CWD) isolate and seven isolates of atypical scrapie into gene-targeted transgenic (Tg) mice expressing the human prion protein (PrP). Upon challenge with these ruminant TSEs, gene-targeted Tg mice expressing human PrP did not show any signs of disease pathology. These data strongly suggest the presence of a substantial transmission barrier between these recently identified ruminant TSEs and humans.

  13. Non-malignant disease mortality in meat workers: a model for studying the role of zoonotic transmissible agents in non-malignant chronic diseases in humans.

    Science.gov (United States)

    Johnson, E S; Zhou, Y; Sall, M; Faramawi, M El; Shah, N; Christopher, A; Lewis, N

    2007-12-01

    Current research efforts have mainly concentrated on evaluating the role of substances present in animal food in the aetiology of chronic diseases in humans, with relatively little attention given to evaluating the role of transmissible agents that are also present. Meat workers are exposed to a variety of transmissible agents present in food animals and their products. This study investigates mortality from non-malignant diseases in workers with these exposures. A cohort mortality study was conducted between 1949 and 1989, of 8520 meat workers in a union in Baltimore, Maryland, who worked in manufacturing plants where animals were killed or processed, and who had high exposures to transmissible agents. Mortality in meat workers was compared with that in a control group of 6081 workers in the same union, and also with the US general population. Risk was estimated by proportional mortality and standardised mortality ratios (SMRs) and relative SMR. A clear excess of mortality from septicaemia, subarachnoid haemorrhage, chronic nephritis, acute and subacute endocarditis, functional diseases of the heart, and decreased risk of mortality from pre-cerebral, cerebral artery stenosis were observed in meat workers when compared to the control group or to the US general population. The authors hypothesise that zoonotic transmissible agents present in food animals and their products may be responsible for the occurrence of some cases of circulatory, neurological and other diseases in meat workers, and possibly in the general population exposed to these agents.

  14. Elephant-to-Human Transmission of Tuberculosis

    Centers for Disease Control (CDC) Podcasts

    2011-02-23

    This podcast reports on the transmission of TB from elephants to humans. Dr. Rendi Murphree, Epidemic Intelligence Service Officer at the Centers for Disease Control and Prevention and Vanderbilt University Visiting Scholar, discusses the recent elephant-to-human transmission of tuberculosis at an elephant refuge in Tennessee.  Created: 2/23/2011 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/23/2011.

  15. UK Iatrogenic Creutzfeldt-Jakob disease: investigating human prion transmission across genotypic barriers using human tissue-based and molecular approaches.

    Science.gov (United States)

    Ritchie, Diane L; Barria, Marcelo A; Peden, Alexander H; Yull, Helen M; Kirkpatrick, James; Adlard, Peter; Ironside, James W; Head, Mark W

    2017-04-01

    Creutzfeldt-Jakob disease (CJD) is the prototypic human prion disease that occurs most commonly in sporadic and genetic forms, but it is also transmissible and can be acquired through medical procedures, resulting in iatrogenic CJD (iCJD). The largest numbers of iCJD cases that have occurred worldwide have resulted from contaminated cadaveric pituitary-derived human growth hormone (hGH) and its use to treat primary and secondary growth hormone deficiency. We report a comprehensive, tissue-based and molecular genetic analysis of the largest series of UK hGH-iCJD cases reported to date, including in vitro kinetic molecular modelling of genotypic factors influencing prion transmission. The results show the interplay of prion strain and host genotype in governing the molecular, pathological and temporal characteristics of the UK hGH-iCJD epidemic and provide insights into the adaptive mechanisms involved when prions cross genotypic barriers. We conclude that all of the available evidence is consistent with the hypothesis that the UK hGH-iCJD epidemic resulted from transmission of the V2 human prion strain, which is associated with the second most common form of sporadic CJD.

  16. Lyme Disease Transmission

    Science.gov (United States)

    ... not known to transmit Lyme disease include Lone star ticks ( Amblyomma americanum ), the American dog tick ( Dermacentor ... of Vector-Borne Diseases (DVBD) Email Recommend Tweet YouTube Instagram Listen Watch RSS ABOUT About CDC Jobs ...

  17. Echinococcosis : disease, detection and transmission

    NARCIS (Netherlands)

    Craig, P.S.; Rogan, M T; Campos-Ponce, M

    2003-01-01

    Echinococcosis is one of the world's most geographically widespread parasitic zoonoses, with transmission occurring in tropical, temperate and arctic biomes. Most human infections are due to Echinococcus granulosus transmitted between domestic dogs and livestock, but this cosmopolitan species also

  18. Molecular Modeling of Prion Transmission to Humans

    Directory of Open Access Journals (Sweden)

    Etienne Levavasseur

    2014-10-01

    Full Text Available Using different prion strains, such as the variant Creutzfeldt-Jakob disease agent and the atypical bovine spongiform encephalopathy agents, and using transgenic mice expressing human or bovine prion protein, we assessed the reliability of protein misfolding cyclic amplification (PMCA to model interspecies and genetic barriers to prion transmission. We compared our PMCA results with in vivo transmission data characterized by attack rates, i.e., the percentage of inoculated mice that developed the disease. Using 19 seed/substrate combinations, we observed that a significant PMCA amplification was only obtained when the mouse line used as substrate is susceptible to the corresponding strain. Our results suggest that PMCA provides a useful tool to study genetic barriers to transmission and to study the zoonotic potential of emerging prion strains.

  19. Human-to-human transmission of Brucella - a systematic review.

    Science.gov (United States)

    Tuon, Felipe F; Gondolfo, Regina B; Cerchiari, Natacha

    2017-05-01

    The most common form of transmitting human brucellosis is through contaminated food or direct contact with infected animals. Human-to-human transmission (HHT) has been described as isolated case reports. The aim of this systematic review was to describe all cases of HHT of human brucellosis reported in the medical literature. A literature search was conducted using PubMed, Scopus and Scielo databases using specific search terms published until March 2016. Two investigators independently determined study eligibility. All clinical data were evaluated to construct a table comprising the most important clinical aspects, age, gender, confirmed infection and detection method, transmission method and HHT confirmation and potential source of infection for human transmission. No statistical method was employed in this study. The initial search resulted in 615 publications, but only 35 were included. 45 brucellosis HHT cases were identified. 61% of patients who acquired brucellosis from another human were <1 year old (newborn and breastfeeding). Other cases include sexual transmission, blood transfusion, bone marrow transplantation and aerosol from an infected patient. Most patients (40/45) presented symptoms upon diagnosis. Diagnostic tests included culture, molecular methods and serum testing. Human brucellosis is a disease liable to transmission between humans by placental barrier, lactation, sexual and tissues such as blood and bone marrow. The indication for screening in tissue banks, transplants, blood and pregnancy is not yet established. © 2017 John Wiley & Sons Ltd.

  20. Potential disease transmission from wild geese and swans to livestock, poultry and humans: a review of the scientific literature from a One Health perspective.

    Science.gov (United States)

    Elmberg, Johan; Berg, Charlotte; Lerner, Henrik; Waldenström, Jonas; Hessel, Rebecca

    2017-01-01

    There are more herbivorous waterfowl (swans and geese) close to humans, livestock and poultry than ever before. This creates widespread conflict with agriculture and other human interests, but also debate about the role of swans and geese as potential vectors of disease of relevance for human and animal health. Using a One Health perspective, we provide the first comprehensive review of the scientific literature about the most relevant viral, bacterial, and unicellular pathogens occurring in wild geese and swans. Research thus far suggests that these birds may play a role in transmission of avian influenza virus, Salmonella, Campylobacter , and antibiotic resistance. On the other hand, at present there is no evidence that geese and swans play a role in transmission of Newcastle disease, duck plague, West Nile virus, Vibrio, Yersinia, Clostridium, Chlamydophila , and Borrelia . Finally, based on present knowledge it is not possible to say if geese and swans play a role in transmission of Escherichia coli, Pasteurella, Helicobacter, Brachyspira, Cryptosporidium, Giardia , and Microsporidia. This is largely due to changes in classification and taxonomy, rapid development of identification methods and lack of knowledge about host specificity. Previous research tends to overrate the role of geese and swans as disease vectors; we do not find any evidence that they are significant transmitters to humans or livestock of any of the pathogens considered in this review. Nevertheless, it is wise to keep poultry and livestock separated from small volume waters used by many wild waterfowl, but there is no need to discourage livestock grazing in nature reserves or pastures where geese and swans are present. Under some circumstances it is warranted to discourage swans and geese from using wastewater ponds, drinking water reservoirs, and public beaches. Intensified screening of swans and geese for AIV, West Nile virus and anatid herpesvirus is warranted.

  1. Bat Hunting and Bat-Human Interactions in Bangladeshi Villages: Implications for Zoonotic Disease Transmission and Bat Conservation.

    Science.gov (United States)

    Openshaw, J J; Hegde, S; Sazzad, H M S; Khan, S U; Hossain, M J; Epstein, J H; Daszak, P; Gurley, E S; Luby, S P

    2017-08-01

    Bats are an important reservoir for emerging zoonotic pathogens. Close human-bat interactions, including the sharing of living spaces and hunting and butchering of bats for food and medicines, may lead to spillover of zoonotic disease into human populations. We used bat exposure and environmental data gathered from 207 Bangladeshi villages to characterize bat exposures and hunting in Bangladesh. Eleven percent of households reported having a bat roost near their homes, 65% reported seeing bats flying over their households at dusk, and 31% reported seeing bats inside their compounds or courtyard areas. Twenty percent of households reported that members had at least daily exposure to bats. Bat hunting occurred in 49% of the villages surveyed and was more likely to occur in households that reported nearby bat roosts (adjusted prevalence ratio [aPR] 2.3, 95% CI 1.1-4.9) and villages located in north-west (aPR 7.5, 95% CI 2.5-23.0) and south-west (aPR 6.8, 95% CI 2.1-21.6) regions. Our results suggest high exposure to bats and widespread hunting throughout Bangladesh. This has implications for both zoonotic disease spillover and bat conservation. © 2016 Blackwell Verlag GmbH.

  2. Malaria transmission in Tripura: Disease distribution & determinants.

    Science.gov (United States)

    Dev, Vas; Adak, Tridibes; Singh, Om P; Nanda, Nutan; Baidya, Bimal K

    2015-12-01

    Malaria is a major public health problem in Tripura and focal disease outbreaks are of frequent occurrence. The state is co-endemic for both Plasmodium falciparum and P. vivax and transmission is perennial and persistent. The present study was aimed to review data on disease distribution to prioritize high-risk districts, and to study seasonal prevalence of disease vectors and their bionomical characteristics to help formulate vector species-specific interventions for malaria control. Data on malaria morbidity in the State were reviewed retrospectively (2008-2012) for understanding disease distribution and transmission dynamics. Cross-sectional mass blood surveys were conducted in malaria endemic villages of South Tripura district to ascertain the prevalence of malaria and proportions of parasite species. Mosquito collections were made in human dwellings of malaria endemic villages aiming at vector incrimination and to study relative abundance, resting and feeding preferences, and their present susceptibility status to DDT. The study showed that malaria was widely prevalent and P. falciparum was the predominant infection (>90%), the remaining were P. vivax cases. The disease distribution, however, was uneven with large concentration of cases in districts of South Tripura and Dhalai coinciding with vast forest cover and tribal populations. Both Anopheles minimus s.s. and An. baimaii were recorded to be prevalent and observed to be highly anthropophagic and susceptible to DDT. Of these, An. minimus was incriminated (sporozoite infection rate 4.92%), and its bionomical characteristics revealed this species to be largely indoor resting and endophagic. For effective control of malaria in the state, it is recommended that diseases surveillance should be robust, and vector control interventions including DDT spray coverage, mass distribution of insecticide-treated nets/ long-lasting insecticidal nets should be intensified prioritizing population groups most at risk to

  3. Ebola (Ebola Virus Disease): Transmission

    Science.gov (United States)

    ... Search Form Controls Cancel Submit Search the CDC Ebola (Ebola Virus Disease) Note: Javascript is disabled or is ... message, please visit this page: About CDC.gov . Ebola (Ebola Virus Disease) What is Ebola Virus Disease? ...

  4. Transmissible Spongiform Encephalopathies (Prion Diseases)

    Science.gov (United States)

    ... This research is aimed at determining how abnormal prion proteins lead to disease, at finding better tests ... This research is aimed at determining how abnormal prion proteins lead to disease, at finding better tests ...

  5. A macroecological characterization of infectious disease transmission:

    DEFF Research Database (Denmark)

    Andersen-Ranberg, Emilie Ulrikka

    2017-01-01

    Presentation: Per M. Jensen*, Miguel L. Grilo, Christian B. Pipper, Emilie U. Andersen-Ranberg. A macroecological characterization of infectious disease transmission: the cases of Mycobacterium and Leptospira sp. The 2017 OIKOS meeting, 10th -11th March 2017, Copenhagen, Denmark......Presentation: Per M. Jensen*, Miguel L. Grilo, Christian B. Pipper, Emilie U. Andersen-Ranberg. A macroecological characterization of infectious disease transmission: the cases of Mycobacterium and Leptospira sp. The 2017 OIKOS meeting, 10th -11th March 2017, Copenhagen, Denmark...

  6. Exploiting Human Resource Requirements to Infer Human Movement Patterns for Use in Modelling Disease Transmission Systems: An Example from Eastern Province, Zambia.

    Directory of Open Access Journals (Sweden)

    Simon Alderton

    Full Text Available In this research, an agent-based model (ABM was developed to generate human movement routes between homes and water resources in a rural setting, given commonly available geospatial datasets on population distribution, land cover and landscape resources. ABMs are an object-oriented computational approach to modelling a system, focusing on the interactions of autonomous agents, and aiming to assess the impact of these agents and their interactions on the system as a whole. An A* pathfinding algorithm was implemented to produce walking routes, given data on the terrain in the area. A* is an extension of Dijkstra's algorithm with an enhanced time performance through the use of heuristics. In this example, it was possible to impute daily activity movement patterns to the water resource for all villages in a 75 km long study transect across the Luangwa Valley, Zambia, and the simulated human movements were statistically similar to empirical observations on travel times to the water resource (Chi-squared, 95% confidence interval. This indicates that it is possible to produce realistic data regarding human movements without costly measurement as is commonly achieved, for example, through GPS, or retrospective or real-time diaries. The approach is transferable between different geographical locations, and the product can be useful in providing an insight into human movement patterns, and therefore has use in many human exposure-related applications, specifically epidemiological research in rural areas, where spatial heterogeneity in the disease landscape, and space-time proximity of individuals, can play a crucial role in disease spread.

  7. Exploiting Human Resource Requirements to Infer Human Movement Patterns for Use in Modelling Disease Transmission Systems: An Example from Eastern Province, Zambia.

    Science.gov (United States)

    Alderton, Simon; Noble, Jason; Schaten, Kathrin; Welburn, Susan C; Atkinson, Peter M

    2015-01-01

    In this research, an agent-based model (ABM) was developed to generate human movement routes between homes and water resources in a rural setting, given commonly available geospatial datasets on population distribution, land cover and landscape resources. ABMs are an object-oriented computational approach to modelling a system, focusing on the interactions of autonomous agents, and aiming to assess the impact of these agents and their interactions on the system as a whole. An A* pathfinding algorithm was implemented to produce walking routes, given data on the terrain in the area. A* is an extension of Dijkstra's algorithm with an enhanced time performance through the use of heuristics. In this example, it was possible to impute daily activity movement patterns to the water resource for all villages in a 75 km long study transect across the Luangwa Valley, Zambia, and the simulated human movements were statistically similar to empirical observations on travel times to the water resource (Chi-squared, 95% confidence interval). This indicates that it is possible to produce realistic data regarding human movements without costly measurement as is commonly achieved, for example, through GPS, or retrospective or real-time diaries. The approach is transferable between different geographical locations, and the product can be useful in providing an insight into human movement patterns, and therefore has use in many human exposure-related applications, specifically epidemiological research in rural areas, where spatial heterogeneity in the disease landscape, and space-time proximity of individuals, can play a crucial role in disease spread.

  8. Chapter 2. Fasciola, lymnaeids and human fascioliasis, with a global overview on disease transmission, epidemiology, evolutionary genetics, molecular epidemiology and control.

    Science.gov (United States)

    Mas-Coma, Santiago; Valero, María Adela; Bargues, María Dolores

    2009-01-01

    Fascioliasis, caused by liver fluke species of the genus Fasciola, has always been well recognized because of its high veterinary impact but it has been among the most neglected diseases for decades with regard to human infection. However, the increasing importance of human fascioliasis worldwide has re-launched interest in fascioliasis. From the 1990s, many new concepts have been developed regarding human fascioliasis and these have furnished a new baseline for the human disease that is very different to a simple extrapolation from fascioliasis in livestock. Studies have shown that human fascioliasis presents marked heterogeneity, including different epidemiological situations and transmission patterns in different endemic areas. This heterogeneity, added to the present emergence/re-emergence of the disease both in humans and animals in many regions, confirms a worrying global scenario. The huge negative impact of fascioliasis on human communities demands rapid action. When analyzing how better to define control measures for endemic areas differing at such a level, it would be useful to have genetic markers that could distinguish each type of transmission pattern and epidemiological situation. Accordingly, this chapter covers aspects of aetiology, geographical distribution, epidemiology, transmission and control in order to obtain a solid baseline for the interpretation of future results. The origins and geographical spread of F. hepatica and F. gigantica in both the ruminant pre-domestication times and the livestock post-domestication period are analyzed. Paleontological, archaeological and historical records, as well as genetic data on recent dispersal of livestock species, are taken into account to establish an evolutionary framework for the two fasciolids across all continents. Emphasis is given to the distributional overlap of both species and the roles of transportation, transhumance and trade in the different overlap situations. Areas with only one Fasciola

  9. Microwave treatment of human milk to prevent transmission of Chagas disease Tratamento do leite humano pelo microondas para prevenir a transmissão de doença de Chagas

    Directory of Open Access Journals (Sweden)

    Cláudio Santos Ferreira

    2003-01-01

    Full Text Available It is recognized that breast feeding is an alternative means of transmission of Chagas disease. However, thermal treatment of milk can prevent this occurrence. As domestic microwave ovens are becoming commonplace, the efficacy of microwave thermal treatment in inactivating Trypanosoma cruzi trypomastigotes in human milk was tested. Human milk samples infected with T. cruzi trypomastigotes (Y strain from laboratory-infected mice, were heated to 63 °C in a domestic microwave oven (2 450 MHz, 700 W. Microscopical and serological examinations demonstrated that none of the animals inoculated orally or intraperitoneally with infected milk which had been treated, got the infection, while those inoculated with untreated, infected milk, became infected. It was concluded that the simple treatment prescribed, which can easily be done at home, was effective in inactivating T. cruzi trypomastigotes contained in human milk.A amamentação é reconhecidamente um modo alternativo de transmissão da doença de Chagas. Entretanto, o tratamento térmico do leite pode evitar tal acidente. Por ser atualmente comum o uso doméstico de fornos de microondas, projetou-se um experimento para avaliar a eficácia do tratamento térmico do leite por microondas na inativação de formas de Trypanosoma cruzi contidas no leite materno. Acrescentaram-se, a amostras de leite humano, tripomastigotas de T. cruzi (cepa Y provenientes de camundongos infectados em laboratório. Essas amostras foram aquecidas a 63 ºC (sete minutos, 45% de potência em forno de microondas doméstico (2 450 MHz, 700 W. Exames microscópicos e sorológicos dos animais inoculados, por via oral ou intraperitoneal, com leite infectado e tratado, foram negativos. Os resultados dos inoculados com leite infectado e não tratado foram positivos. Concluiu-se que este é um processo simples e eficaz para inativar tripomastigotas contidos em leite, podendo facilmente ser executado em ambiente doméstico.

  10. Research on an infectious disease transmission by flocking birds.

    Science.gov (United States)

    Tang, Mingsheng; Mao, Xinjun; Guessoum, Zahia

    2013-01-01

    The swarm intelligence is becoming a hot topic. The flocking of birds is a natural phenomenon, which is formed and organized without central or external controls for some benefits (e.g., reduction of energy consummation). However, the flocking also has some negative effects on the human, as the infectious disease H7N9 will easily be transmited from the denser flocking birds to the human. Zombie-city model has been proposed to help analyzing and modeling the flocking birds and the artificial society. This paper focuses on the H7N9 virus transmission in the flocking birds and from the flocking birds to the human. And some interesting results have been shown: (1) only some simple rules could result in an emergence such as the flocking; (2) the minimum distance between birds could affect H7N9 virus transmission in the flocking birds and even affect the virus transmissions from the flocking birds to the human.

  11. When More Transmission Equals Less Disease: Reconciling the Disconnect between Disease Hotspots and Parasite Transmission

    Science.gov (United States)

    Park, Andrew W.; Magori, Krisztian; White, Brad A.; Stallknecht, David E.

    2013-01-01

    The assumed straightforward connection between transmission intensity and disease occurrence impacts surveillance and control efforts along with statistical methodology, including parameter inference and niche modeling. Many infectious disease systems have the potential for this connection to be more complicated–although demonstrating this in any given disease system has remained elusive. Hemorrhagic disease (HD) is one of the most important diseases of white-tailed deer and is caused by viruses in the Orbivirus genus. Like many infectious diseases, the probability or severity of disease increases with age (after loss of maternal antibodies) and the probability of disease is lower upon re-infection compared to first infection (based on cross-immunity between virus strains). These broad criteria generate a prediction that disease occurrence is maximized at intermediate levels of transmission intensity. Using published US field data, we first fit a statistical model to predict disease occurrence as a function of seroprevalence (a proxy for transmission intensity), demonstrating that states with intermediate seroprevalence have the highest level of case reporting. We subsequently introduce an independently parameterized mechanistic model supporting the theory that high case reporting should come from areas with intermediate levels of transmission. This is the first rigorous demonstration of this phenomenon and illustrates that variation in transmission rate (e.g. along an ecologically-controlled transmission gradient) can create cryptic refuges for infectious diseases. PMID:23579922

  12. A mathematical model of Chagas disease transmission

    Science.gov (United States)

    Hidayat, Dayat; Nugraha, Edwin Setiawan; Nuraini, Nuning

    2018-03-01

    Chagas disease is a parasitic infection caused by protozoan Trypanosoma cruzi which is transmitted to human by insects of the subfamily Triatominae, including Rhodnius prolixus. This disease is a major problem in several countries of Latin America. A mathematical model of Chagas disease with separate vector reservoir and a neighboring human resident is constructed. The basic reproductive ratio is obtained and stability analysis of the equilibria is shown. We also performed sensitivity populations dynamics of infected humans and infected insects based on migration rate, carrying capacity, and infection rate parameters. Our findings showed that the dynamics of the infected human and insect is mostly affected by carrying capacity insect in the settlement.

  13. Chagas disease transmission by consumption of game meat: systematic review.

    Science.gov (United States)

    Sangenis, Luiz Henrique Conde; Nielebock, Marco Antonio Prates; Santos, Ceumara da Silva; Silva, Mateus Curty Carriello da; Bento, Glauber Motta Ribeiro

    2016-01-01

    To evaluate the influence of game meat consumption in Chagas disease (CD) transmission, the conditions under which it occurs and the frequency of reports in the literature. Through systematic review, databases PubMed, LILACS, MEDLINE, and SciELO were consulted, and articles written in Portuguese, English, and Spanish were included, with no limitation over publication date. We used the following descriptors: oral, transmission, meat, wild animals, hunt, carnivory, and Chagas disease. Articles that mentioned consumption of animal meat as a form of human transmission of CD were included. We used epidemiological, clinical, and laboratory evidence criteria to confirm cases. Among the 298 articles identified, only six met the eligibility criteria. Only five episodes of oral transmission through wild animal meat or blood consumption were identified. However, in two of them, the possibility of vectorial transmission could not be ruled out. Most reports met the epidemiological, clinical, and laboratory evidence criteria established to support the transmission. Though CD transmission is uncommon, hunting and consumption of wild mammals that serve as Trypanosoma cruzi reservoirs should be discouraged in endemic countries in light of the risks inherent to these practices.

  14. Modeling seasonal behavior changes and disease transmission with application to chronic wasting disease.

    Science.gov (United States)

    Oraby, Tamer; Vasilyeva, Olga; Krewski, Daniel; Lutscher, Frithjof

    2014-01-07

    Behavior and habitat of wildlife animals change seasonally according to environmental conditions. Mathematical models need to represent this seasonality to be able to make realistic predictions about the future of a population and the effectiveness of human interventions. Managing and modeling disease in wild animal populations requires particular care in that disease transmission dynamics is a critical consideration in the etiology of both human and animal diseases, with different transmission paradigms requiring different disease risk management strategies. Since transmission of infectious diseases among wildlife depends strongly on social behavior, mechanisms of disease transmission could also change seasonally. A specific consideration in this regard confronted by modellers is whether the contact rate between individuals is density-dependent or frequency-dependent. We argue that seasonal behavior changes could lead to a seasonal shift between density and frequency dependence. This hypothesis is explored in the case of chronic wasting disease (CWD), a fatal disease that affects deer, elk and moose in many areas of North America. Specifically, we introduce a strategic CWD risk model based on direct disease transmission that accounts for the seasonal change in the transmission dynamics and habitats occupied, guided by information derived from cervid ecology. The model is composed of summer and winter susceptible-infected (SI) equations, with frequency-dependent and density-dependent transmission dynamics, respectively. The model includes impulsive birth events with density-dependent birth rate. We determine the basic reproduction number as a weighted average of two seasonal reproduction numbers. We parameterize the model from data derived from the scientific literature on CWD and deer ecology, and conduct global and local sensitivity analyses of the basic reproduction number. We explore the effectiveness of different culling strategies for the management of CWD

  15. Human immunodeficiency virus-associated disruption of mucosal barriers and its role in HIV transmission and pathogenesis of HIV/AIDS disease

    Science.gov (United States)

    Tugizov, Sharof

    2016-01-01

    Abstract Oral, intestinal and genital mucosal epithelia have a barrier function to prevent paracellular penetration by viral, bacterial and other pathogens, including human immunodeficiency virus (HIV). HIV can overcome these barriers by disrupting the tight and adherens junctions of mucosal epithelia. HIV-associated disruption of epithelial junctions may also facilitate paracellular penetration and dissemination of other viral pathogens. This review focuses on possible molecular mechanisms of HIV-associated disruption of mucosal epithelial junctions and its role in HIV transmission and pathogenesis of HIV and acquired immune deficiency syndrome (AIDS). PMID:27583187

  16. High probability of avian influenza virus (H7N7) transmission from poultry to humans active in disease control on infected farms

    NARCIS (Netherlands)

    M.E.H. Bos (Marian); D.E. te Beest (Dennis); M. van Boven (Michiel); M.R.D.R.B. van Holle; A. Meijer (Adam); A. Bosman (Arnold); Y.M. Mulder (Yonne); M.P.G. Koopmans D.V.M. (Marion); A. Stegeman (Arjan)

    2010-01-01

    textabstractAn epizootic of avian influenza (H7N7) caused a large number of human infections in The Netherlands in 2003. We used data from this epizootic to estimate infection probabilities for persons involved in disease control on infected farms. Analyses were based on databases containing

  17. Lateral force transmission between human tendon fascicles

    DEFF Research Database (Denmark)

    Haraldsson, Bjarki T; Aagaard, Per; Qvortrup, Klaus

    2008-01-01

    Whether adjacent collagen fascicles transmit force in parallel is unknown. The purpose of the present study was to examine the magnitude of lateral force transmission between adjacent collagen fascicles from the human patellar and Achilles tendon. From each sample two adjacent strands of fascicles...... was transversally cut while the other fascicle and the fascicular membrane were kept intact. Cycle 3: both fascicles were cut in opposite ends while the fascicular membrane was left intact. A decline in peak force of 45% and 55% from cycle 1 to cycle 2, and 93% and 92% from cycle 2 to cycle 3 was observed...... in the patellar and Achilles tendon fascicles, respectively. A decline in stiffness of 39% and 60% from cycle 1 to cycle 2, and of 93% and 100% from cycle 2 to cycle 3 was observed in the patellar and Achilles tendon fascicles, respectively. The present data demonstrate that lateral force transmission between...

  18. Detecting emerging transmissibility of avian influenza virus in human households.

    Directory of Open Access Journals (Sweden)

    Michiel van Boven

    2007-07-01

    Full Text Available Accumulating infections of highly pathogenic H5N1 avian influenza in humans underlines the need to track the ability of these viruses to spread among humans. A human-transmissible avian influenza virus is expected to cause clusters of infections in humans living in close contact. Therefore, epidemiological analysis of infection clusters in human households is of key importance. Infection clusters may arise from transmission events from (i the animal reservoir, (ii humans who were infected by animals (primary human-to-human transmission, or (iii humans who were infected by humans (secondary human-to-human transmission. Here we propose a method of analysing household infection data to detect changes in the transmissibility of avian influenza viruses in humans at an early stage. The method is applied to an outbreak of H7N7 avian influenza virus in The Netherlands that was the cause of more than 30 human-to-human transmission events. The analyses indicate that secondary human-to-human transmission is plausible for the Dutch household infection data. Based on the estimates of the within-household transmission parameters, we evaluate the effectiveness of antiviral prophylaxis, and conclude that it is unlikely that all household infections can be prevented with current antiviral drugs. We discuss the applicability of our method for the detection of emerging human-to-human transmission of avian influenza viruses in particular, and for the analysis of within-household infection data in general.

  19. Research on an Infectious Disease Transmission by Flocking Birds

    Directory of Open Access Journals (Sweden)

    Mingsheng Tang

    2013-01-01

    Full Text Available The swarm intelligence is becoming a hot topic. The flocking of birds is a natural phenomenon, which is formed and organized without central or external controls for some benefits (e.g., reduction of energy consummation. However, the flocking also has some negative effects on the human, as the infectious disease H7N9 will easily be transmited from the denser flocking birds to the human. Zombie-city model has been proposed to help analyzing and modeling the flocking birds and the artificial society. This paper focuses on the H7N9 virus transmission in the flocking birds and from the flocking birds to the human. And some interesting results have been shown: (1 only some simple rules could result in an emergence such as the flocking; (2 the minimum distance between birds could affect H7N9 virus transmission in the flocking birds and even affect the virus transmissions from the flocking birds to the human.

  20. Human Environmental Disease Network

    DEFF Research Database (Denmark)

    Taboureau, Olivier; Audouze, Karine

    2017-01-01

    During the past decades, many epidemiological, toxicological and biological studies have been performed to assess the role of environmental chemicals as potential toxicants for diverse human disorders. However, the relationships between diseases based on chemical exposure have been rarely studied...... by computational biology. We developed a human environmental disease network (EDN) to explore and suggest novel disease-disease and chemical-disease relationships. The presented scored EDN model is built upon the integration on systems biology and chemical toxicology using chemical contaminants information...... and their disease relationships from the reported TDDB database. The resulting human EDN takes into consideration the level of evidence of the toxicant-disease relationships allowing including some degrees of significance in the disease-disease associations. Such network can be used to identify uncharacterized...

  1. Perinatal transmission of human papilomavirus DNA

    Directory of Open Access Journals (Sweden)

    Serafini Eduardo P

    2009-06-01

    Full Text Available Abstract The purpose was to study the perinatal transmission of human papillomavirus DNA (HPV-DNA in 63 mother-newborn pairs, besides looking at the epidemiological factors involved in the viral DNA transmission. The following sampling methods were used: (1 in the pregnant woman, when was recruited, in cervix and clinical lesions of the vagina, vulva and perineal region; (2 in the newborn, (a buccal, axillary and inguinal regions; (b nasopharyngeal aspirate, and (c cord blood; (3 in the children, buccal was repeated in the 4th week and 6th and 12th month of life. HPV-DNA was identified using two methodologies: multiplex PCR (PGMY09 and MY11 primers and nested-PCR (genotypes 6/11, 16, 18, 31, 33, 42, 52 and 58. Perinatal transmission was considered when concordance was found in type-specific HPV between mother/newborn or mother/child. HPV-DNA genital was detected in 49 pregnant women submitted to delivery. Eleven newborns (22.4%, n = 11/49 were HPV-DNA positive. In 8 cases (16.3%, n = 8/49 there was type specific HPV concordance between mother/newborn samples. At the end of the first month of life three children (6.1%, n = 3/49 became HPV-DNA positive, while two remained positive from birth. In 3 cases (100%, n = 3/3 there was type specific HPV concordance between mother/newborn samples. In the 6th month, a child (2%, n = 1/49 had become HPV-DNA positive between the 1st and 6th month of life, and there was type specific HPV concordance of mother/newborn samples. All the HPV-DNA positive children (22.4%, n = 11/49 at birth and at the end first month of life (6.1%, n = 3/49 became HPV-DNA negative at the age of 6 months. The HPV-DNA positive child (2%, n = 1/49 from 1st to the 6th month of life became HPV-DNA negative between the 6th and 12th month of life and one child had anogenital warts. In the twelfth month all (100%, n = 49/49 the children studied were HPV-DNA negative. A positive and significant correlation was observed between perinatal

  2. Human to human transmission of arthropod-borne pathogens

    NARCIS (Netherlands)

    Martina, Byron E.; Barzon, Luisa; Pijlman, Gorben P.; Fuente, de la José; Rizzoli, Annapaola; Wammes, Linda J.; Takken, Willem; Rij, van Ronald P.; Papa, Anna

    2017-01-01

    Human-to-human (H2H) transmitted arthropod-borne pathogens are a growing burden worldwide, with malaria and dengue being the most common mosquito-borne H2H transmitted diseases. The ability of vectors to get infected by humans during a blood meal to further propel an epidemic depends on complex

  3. Human to human transmission of arthropod-borne pathogens

    NARCIS (Netherlands)

    Martina, B.E.; Barzon, L.; Pijlman, G.P.; Fuente, J. de la; Rizzoli, A.; Wammes, L.J.; Takken, W.; Rij, R.P. van; Papa, A.

    2017-01-01

    Human-to-human (H2H) transmitted arthropod-borne pathogens are a growing burden worldwide, with malaria and dengue being the most common mosquito-borne H2H transmitted diseases. The ability of vectors to get infected by humans during a blood meal to further propel an epidemic depends on complex

  4. Pasteurization of human milk to prevent transmission of Chagas disease Pasteurização de leite humano para evitar a transmissão da doença de Chagas

    Directory of Open Access Journals (Sweden)

    Cláudio Santos FERREIRA

    2001-06-01

    Full Text Available Although admittedly transmission of Trypanosoma cruzi infection through breastfeeding is a rare event, it involves serious risks. To test the effectiveness of pasteurization in preventing this mode of infection, three sets of samples of human milk were tested: a - contaminated with T. cruzi and pasteurized; b - contaminated with T. cruzi and non-pasteurized; c - non-contaminated and pasteurized. Samples from all sets were orally and intraperitoneally administered to 90 BALB/c mice. The animals inoculated with contaminated, non-pasteurized samples, got the infection. Controls and the animals inoculated with contaminated and pasteurized milk were not infected. The hypothesis was accepted that pasteurization inactivates T. cruzi trypomastigotes.A amamentação é modo alternativo de transmitir-se a doença de Chagas. Embora admitida como evento raro, a infecção por esta via é preocupante. Para evitá-la é sugerida a pasteurização. Separaram-se para o ensaio três conjuntos de amostras de leite humano: a - contaminadas por Trypanosoma cruzi e pasteurizadas; b - contaminadas por T. cruzi e não pasteurizadas; c - não contaminadas e pasteurizadas. Frações dos três conjuntos foram inoculadas por vias oral e intraperitoneal em 90 camundongos BALB/c. Os animais inoculados com leite contaminado e não pasteurizado infectaram-se. Os controles e os inoculados com leite contaminado e pasteurizado não se infectaram. Aceitou-se a hipótese de a pasteurização ter inativado as formas tripomastigotas de T. cruzi em suspensão no leite.

  5. Did transmission of Helicobacter pylori from humans cause a disease outbreak in a colony of Stripe-faced Dunnarts (Sminthopsis macroura?

    Directory of Open Access Journals (Sweden)

    Every Alison L

    2011-02-01

    Full Text Available Abstract Since the discovery that Helicobacter pylori causes a range of pathologies in the stomachs of infected humans, it has become apparent that Helicobacters are found in a diverse range of animal species where they are frequently associated with disease. In 2003 and 2004, there were two outbreaks of increased mortality associated with gastric bleeding and weight-loss in a captive colony of the Australian marsupial, the Stripe-faced Dunnart (Sminthopsis macroura. The presence of gastric pathology led to an investigation of potential Helicobacter pathogenesis in these animals. Histological examination revealed the presence of gastritis, and PCR analysis confirmed the presence of Helicobacter infection in the stomachs of these marsupials. Surprisingly, sequencing of 16S rRNA from these bacteria identified the species as H. pylori and PCR confirmed the strain to be positive for the important pathogenesis factor, cagA. We therefore describe, for the first time, an apparent reverse zoonotic infection of Stripe-faced Dunnarts with H. pylori. Already prone to pathological effects of stress (as experienced during breeding season, concomitant H. pylori infection appears to be a possible essential but not sufficient co-factor in prototypic gastric bleeding and weight loss in these marsupials. The Stripe-faced Dunnart could represent a new model for investigating Helicobacter-driven gastric pathology. Infections from their human handlers, specifically of H. pylori, may be a potential risk to captive colonies of marsupials.

  6. Transmission and epidemiology of zoonotic protozoal diseases of companion animals.

    Science.gov (United States)

    Esch, Kevin J; Petersen, Christine A

    2013-01-01

    Over 77 million dogs and 93 million cats share our households in the United States. Multiple studies have demonstrated the importance of pets in their owners' physical and mental health. Given the large number of companion animals in the United States and the proximity and bond of these animals with their owners, understanding and preventing the diseases that these companions bring with them are of paramount importance. Zoonotic protozoal parasites, including toxoplasmosis, Chagas' disease, babesiosis, giardiasis, and leishmaniasis, can cause insidious infections, with asymptomatic animals being capable of transmitting disease. Giardia and Toxoplasma gondii, endemic to the United States, have high prevalences in companion animals. Leishmania and Trypanosoma cruzi are found regionally within the United States. These diseases have lower prevalences but are significant sources of human disease globally and are expanding their companion animal distribution. Thankfully, healthy individuals in the United States are protected by intact immune systems and bolstered by good nutrition, sanitation, and hygiene. Immunocompromised individuals, including the growing number of obese and/or diabetic people, are at a much higher risk of developing zoonoses. Awareness of these often neglected diseases in all health communities is important for protecting pets and owners. To provide this awareness, this review is focused on zoonotic protozoal mechanisms of virulence, epidemiology, and the transmission of pathogens of consequence to pet owners in the United States.

  7. Relating phylogenetic trees to transmission trees of infectious disease outbreaks.

    Science.gov (United States)

    Ypma, Rolf J F; van Ballegooijen, W Marijn; Wallinga, Jacco

    2013-11-01

    Transmission events are the fundamental building blocks of the dynamics of any infectious disease. Much about the epidemiology of a disease can be learned when these individual transmission events are known or can be estimated. Such estimations are difficult and generally feasible only when detailed epidemiological data are available. The genealogy estimated from genetic sequences of sampled pathogens is another rich source of information on transmission history. Optimal inference of transmission events calls for the combination of genetic data and epidemiological data into one joint analysis. A key difficulty is that the transmission tree, which describes the transmission events between infected hosts, differs from the phylogenetic tree, which describes the ancestral relationships between pathogens sampled from these hosts. The trees differ both in timing of the internal nodes and in topology. These differences become more pronounced when a higher fraction of infected hosts is sampled. We show how the phylogenetic tree of sampled pathogens is related to the transmission tree of an outbreak of an infectious disease, by the within-host dynamics of pathogens. We provide a statistical framework to infer key epidemiological and mutational parameters by simultaneously estimating the phylogenetic tree and the transmission tree. We test the approach using simulations and illustrate its use on an outbreak of foot-and-mouth disease. The approach unifies existing methods in the emerging field of phylodynamics with transmission tree reconstruction methods that are used in infectious disease epidemiology.

  8. Seven challenges for modelling indirect transmission: Vector-borne diseases, macroparasites and neglected tropical diseases

    Directory of Open Access Journals (Sweden)

    T. Déirdre Hollingsworth

    2015-03-01

    Full Text Available Many of the challenges which face modellers of directly transmitted pathogens also arise when modelling the epidemiology of pathogens with indirect transmission – whether through environmental stages, vectors, intermediate hosts or multiple hosts. In particular, understanding the roles of different hosts, how to measure contact and infection patterns, heterogeneities in contact rates, and the dynamics close to elimination are all relevant challenges, regardless of the mode of transmission. However, there remain a number of challenges that are specific and unique to modelling vector-borne diseases and macroparasites. Moreover, many of the neglected tropical diseases which are currently targeted for control and elimination are vector-borne, macroparasitic, or both, and so this article includes challenges which will assist in accelerating the control of these high-burden diseases. Here, we discuss the challenges of indirect measures of infection in humans, whether through vectors or transmission life stages and in estimating the contribution of different host groups to transmission. We also discuss the issues of “evolution-proof” interventions against vector-borne disease.

  9. Seven challenges for modelling indirect transmission: vector-borne diseases, macroparasites and neglected tropical diseases.

    Science.gov (United States)

    Hollingsworth, T Déirdre; Pulliam, Juliet R C; Funk, Sebastian; Truscott, James E; Isham, Valerie; Lloyd, Alun L

    2015-03-01

    Many of the challenges which face modellers of directly transmitted pathogens also arise when modelling the epidemiology of pathogens with indirect transmission--whether through environmental stages, vectors, intermediate hosts or multiple hosts. In particular, understanding the roles of different hosts, how to measure contact and infection patterns, heterogeneities in contact rates, and the dynamics close to elimination are all relevant challenges, regardless of the mode of transmission. However, there remain a number of challenges that are specific and unique to modelling vector-borne diseases and macroparasites. Moreover, many of the neglected tropical diseases which are currently targeted for control and elimination are vector-borne, macroparasitic, or both, and so this article includes challenges which will assist in accelerating the control of these high-burden diseases. Here, we discuss the challenges of indirect measures of infection in humans, whether through vectors or transmission life stages and in estimating the contribution of different host groups to transmission. We also discuss the issues of "evolution-proof" interventions against vector-borne disease. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  10. Prevalence of Human Immunodeficiency Virus Transmission among ...

    African Journals Online (AJOL)

    sex, and social status with the subjects served as control. Voluntary counseling ... to HIV antibody. Conclusions: Blood transfusion is still a risk factor for HIV transmission .... 1.6% documented by Al-Mahroos and Ebrahim[15] in Bahrain. Island.

  11. Biodiversity and disease: a synthesis of ecological perspectives on Lyme disease transmission.

    Science.gov (United States)

    Wood, Chelsea L.; Lafferty, Kevin D.

    2013-01-01

    Recent reviews have argued that disease control is among the ecosystem services yielded by biodiversity. Lyme disease (LD) is commonly cited as the best example of the ‘diluting’ effect of biodiversity on disease transmission, but many studies document the opposite relationship, showing that human LD risk can increase with forestation. Here, we unify these divergent perspectives and find strong evidence for a positive link between biodiversity and LD at broad spatial scales (urban to suburban to rural) and equivocal evidence for a negative link between biodiversity and LD at varying levels of biodiversity within forests. This finding suggests that, across zoonotic disease agents, the biodiversity–disease relationship is scale dependent and complex.

  12. Vaccine preventable viral diseases and risks associated with waterborne transmission

    Directory of Open Access Journals (Sweden)

    Franco Maria Ruggeri

    2012-12-01

    Full Text Available Rotavirus and poliovirus are paradigmatic viruses for causing major diseases affecting the human population. The impact of poliovirus is remarkably diminished because of vaccination during the last half century. Poliomyelitis due to wild polio currently affects a limited number of countries, and since 2000 sporadic outbreaks have been associated to neurovirulent vaccine-derived polioviruses. Conversely, rotavirus is presently very diffuse, accounting for the largest fraction of severe gastroenteritis among children <5 years-old. Vaccination towards rotavirus is still in its dawn, and zoonotic strains contribute to the emergence and evolution of novel strains pathogenic to man. The environment, particularly surface water, is a possible vehicle for large transmission of both viruses, but environmental surveillance of circulating strains can help promptly monitor entry of new virulent strains into a country, their shedding and spread.

  13. Aerobiology and Its Role in the Transmission of Infectious Diseases

    Directory of Open Access Journals (Sweden)

    Aaron Fernstrom

    2013-01-01

    Full Text Available Aerobiology plays a fundamental role in the transmission of infectious diseases. As infectious disease and infection control practitioners continue employing contemporary techniques (e.g., computational fluid dynamics to study particle flow, polymerase chain reaction methodologies to quantify particle concentrations in various settings, and epidemiology to track the spread of disease, the central variables affecting the airborne transmission of pathogens are becoming better known. This paper reviews many of these aerobiological variables (e.g., particle size, particle type, the duration that particles can remain airborne, the distance that particles can travel, and meteorological and environmental factors, as well as the common origins of these infectious particles. We then review several real-world settings with known difficulties controlling the airborne transmission of infectious particles (e.g., office buildings, healthcare facilities, and commercial airplanes, while detailing the respective measures each of these industries is undertaking in its effort to ameliorate the transmission of airborne infectious diseases.

  14. Detecting emerging transmissibility of avian influenza virus in human households

    NARCIS (Netherlands)

    Boven, M. van; Koopmans, M.; Du Ry van Beest Holle, M.; Meijer, Adam; Klinkenberg, D.; Donnelly, C.A.; Heesterbeek, J.A.P.

    Accumulating infections of highly pathogenic H5N1 avian influenza in humans underlines the need to track the ability of these viruses to spread among humans. A human-transmissible avian influenza virus is expected to cause clusters of infections in humans living in close contact. Therefore,

  15. Detecting emerging transmissibility of avian influenza virus in human households

    NARCIS (Netherlands)

    Boven, van R.M.; Koopmans, M.; Du Ry Beest Holle, van M.; Meijer, A.; Klinkenberg, D.; Donnelly, C.; Heesterbeek, J.A.P.

    2007-01-01

    Accumulating infections of highly pathogenic H5N1 avian influenza in humans underlines the need to track the ability of these viruses to spread among humans. A human-transmissible avian influenza virus is expected to cause clusters of infections in humans living in close contact. Therefore,

  16. Streptococcus equi subspecies zooepidemicus Infections in Humans by Zoonotic Transmission from Horses

    Centers for Disease Control (CDC) Podcasts

    2013-06-12

    Dr. Mike Miller reads an abridged version of the Emerging Infectious Diseases’ article, Streptococcus equi subspecies zooepidemicus Infections in Humans by Zoonotic Transmission from Horses.  Created: 6/12/2013 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 7/3/2013.

  17. Humanized mouse models: Application to human diseases.

    Science.gov (United States)

    Ito, Ryoji; Takahashi, Takeshi; Ito, Mamoru

    2018-05-01

    Humanized mice are superior to rodents for preclinical evaluation of the efficacy and safety of drug candidates using human cells or tissues. During the past decade, humanized mouse technology has been greatly advanced by the establishment of novel platforms of genetically modified immunodeficient mice. Several human diseases can be recapitulated using humanized mice due to the improved engraftment and differentiation capacity of human cells or tissues. In this review, we discuss current advanced humanized mouse models that recapitulate human diseases including cancer, allergy, and graft-versus-host disease. © 2017 Wiley Periodicals, Inc.

  18. Foot-and-mouth Disease Transmission in Africa

    NARCIS (Netherlands)

    Tekleghiorghis, T.; Moormann, R.J.M.; Weerdmeester, K.; Dekker, A.

    2016-01-01

    In Africa, for the control of foot-and-mouth disease (FMD), more information is needed on the spread of the disease at local, regional and inter-regional level. The aim of this review is to identify the role that animal husbandry, trade and wildlife have on the transmission of FMD and to provide

  19. Transmission dynamics of lumpy skin disease in Ethiopia

    NARCIS (Netherlands)

    Molla, W.; Frankena, Klaas; Jong, de Mart

    2017-01-01

    Lumpy skin disease (LSD) is a severe disease of cattle caused by a Capripoxvirus and often caused epidemics in Ethiopia and many other countries. This study was undertaken to quantify the transmission between animals and to estimate the infection reproduction ratio in a predominantly mixed

  20. Infectious Disease Transmission during Transfusion and Transplantation

    Centers for Disease Control (CDC) Podcasts

    2012-08-13

    Dr. Matthew Kuehnert, Director of the Office of Blood, Organ, and Other Tissue Safety, discusses infections in transplants.  Created: 8/13/2012 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 8/15/2012.

  1. Linking Microbiota to Human Diseases

    DEFF Research Database (Denmark)

    Wu, Hao; Tremaroli, Valentina; Bäckhed, F

    2015-01-01

    The human gut microbiota encompasses a densely populated ecosystem that provides essential functions for host development, immune maturation, and metabolism. Alterations to the gut microbiota have been observed in numerous diseases, including human metabolic diseases such as obesity, type 2...

  2. in Human Liver Diseases

    Directory of Open Access Journals (Sweden)

    Minoru Fujimoto

    2010-01-01

    Full Text Available Toll-like receptor (TLR signaling pathways are strictly coordinated by several mechanisms to regulate adequate innate immune responses. Recent lines of evidence indicate that the suppressor of cytokine signaling (SOCS family proteins, originally identified as negative-feedback regulators in cytokine signaling, are involved in the regulation of TLR-mediated immune responses. SOCS1, a member of SOCS family, is strongly induced upon TLR stimulation. Cells lacking SOCS1 are hyperresponsive to TLR stimulation. Thus, SOCS1 is an important regulator for both cytokine and TLR-induced responses. As an immune organ, the liver contains various types of immune cells such as T cells, NK cells, NKT cells, and Kupffer cells and is continuously challenged with gut-derived bacterial and dietary antigens. SOCS1 may be implicated in pathophysiology of the liver. The studies using SOCS1-deficient mice revealed that endogenous SOCS1 is critical for the prevention of liver diseases such as hepatitis, cirrhosis, and cancers. Recent studies on humans suggest that SOCS1 is involved in the development of various liver disorders in humans. Thus, SOCS1 and other SOCS proteins are potential targets for the therapy of human liver diseases.

  3. A survey of basic reproductive ratios in vector-borne disease transmission modeling

    Science.gov (United States)

    Soewono, E.; Aldila, D.

    2015-03-01

    Vector-borne diseases are commonly known in tropical and subtropical countries. These diseases have contributed to more than 10% of world infectious disease cases. Among the vectors responsible for transmitting the diseases are mosquitoes, ticks, fleas, flies, bugs and worms. Several of the diseases are known to contribute to the increasing threat to human health such as malaria, dengue, filariasis, chikungunya, west nile fever, yellow fever, encephalistis, and anthrax. It is necessary to understand the real process of infection, factors which contribute to the complication of the transmission in order to come up with a good and sound mathematical model. Although it is not easy to simulate the real transmission process of the infection, we could say that almost all models have been developed from the already long known Host-Vector model. It constitutes the main transmission processes i.e. birth, death, infection and recovery. From this simple model, the basic concepts of Disease Free and Endemic Equilibria and Basic Reproductive Ratio can be well explained and understood. Theoretical, modeling, control and treatment aspects of disease transmission problems have then been developed for various related diseases. General construction as well as specific forms of basic reproductive ratios for vector-borne diseases are discusses here.

  4. Molecular Pathology of Human Prion Diseases

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available Prion diseases are fatal neurodegenerative conditions in humans and animals. In this review, we summarize the molecular background of phenotypic variability, relation of prion protein (PrP to other proteins associated with neurodegenerative diseases, and pathogenesis of neuronal vulnerability. PrP exists in different forms that may be present in both diseased and non-diseased brain, however, abundant disease-associated PrP together with tissue pathology characterizes prion diseases and associates with transmissibility. Prion diseases have different etiological background with distinct pathogenesis and phenotype. Mutations of the prion protein gene are associated with genetic forms. The codon 129 polymorphism in combination with the Western blot pattern of PrP after proteinase K digestion serves as a basis for molecular subtyping of sporadic Creutzfeldt-Jakob disease. Tissue damage may result from several parallel, interacting or subsequent pathways that involve cellular systems associated with synapses, protein processing, oxidative stress, autophagy, and apoptosis.

  5. Monkeypox disease transmission in an experimental setting: prairie dog animal model.

    Directory of Open Access Journals (Sweden)

    Christina L Hutson

    Full Text Available Monkeypox virus (MPXV is considered the most significant human public health threat in the genus Orthopoxvirus since the eradication of variola virus (the causative agent of smallpox. MPXV is a zoonotic agent endemic to forested areas of Central and Western Africa. In 2003, MPXV caused an outbreak in the United States due to the importation of infected African rodents, and subsequent sequential infection of North American prairie dogs (Cynomys ludovicianus and humans. In previous studies, the prairie dog MPXV model has successfully shown to be very useful for understanding MPXV since the model emulates key characteristics of human monkeypox disease. In humans, percutaneous exposure to animals has been documented but the primary method of human-to-human MPXV transmission is postulated to be by respiratory route. Only a few animal model studies of MPXV transmission have been reported. Herein, we show that MPXV infected prairie dogs are able to transmit the virus to naive animals through multiple transmission routes. All secondarily exposed animals were infected with MPXV during the course of the study. Notably, animals secondarily exposed appeared to manifest more severe disease; however, the disease course was very similar to those of experimentally challenged animals including inappetence leading to weight loss, development of lesions, production of orthopoxvirus antibodies and shedding of similar levels or in some instances higher levels of MPXV from the oral cavity. Disease was transmitted via exposure to contaminated bedding, co-housing, or respiratory secretions/nasal mucous (we could not definitively say that transmission occurred via respiratory route exclusively. Future use of the model will allow us to evaluate infection control measures, vaccines and antiviral strategies to decrease disease transmission.

  6. Cosmic Transmission of Periodontal, Cardiovascular and Kidney Disease via Nanobacteria

    Directory of Open Access Journals (Sweden)

    Jafar Kolahi

    2011-04-01

    Full Text Available Introduction: Nanobacteria (NB are mysterious particles that have spurred one of the biggest controversies in modern micro-biology. NB has been reported to be present in animal and human blood, tissue culture cell lines, wastewater and etc. NB appear to cause or contribute to common diseases of the mankind e.g. periodontitis, formation of kidney stone, heart calcifications, coronary artery calcification, atherosclerotic plaque. Recent data on the far-ultraviolet extinction of starlight in our galaxy and in external galaxies is interpreted in terms of the widespread occurrence of organic particles of optical refractive index 1.4 and radii less than or equal to 20 nm. Such particles are candidates for NB such as recently been found in abundance on the Earth. Unbelievably nanobacteria-like rods observed at the surface of the Tataouine meteorite and Martian rock.The hypothesis: It seems logic to hypothesize that aliens from inner space, nanobacteria, can bring us new disease such as periodontal, cardiovascular and kidney diseases via space travels or meteorites or interstellar dusts.Evaluation of the hypothesis: The main criticism with this idea is how NB can keep alive during transfer among seriously life threatening condition in interstellar space. NB are generally thought to be very difficult to deactivation, exceptionally resistant to heat, are not deactivated by physical or chemical treatments including autoclaving, UV treatment, and various biocides. Health care providers, health policy makers and space agencies e.g. NASA and European Space Agency should make a concentrated effort to prevent transmission of NB especially following space travels.

  7. Relevance of indirect transmission for wildlife disease surveillance

    Directory of Open Access Journals (Sweden)

    Martin Lange

    2016-11-01

    Full Text Available Epidemiological models of infectious diseases are essential tools in support of risk assessment, surveillance design and contingency planning in public and animal health. Direct pathogen transmission from host to host is an essential process of each host-pathogen system and respective epidemiological modelling concepts. It is widely accepted that numerous diseases involve indirect transmission through pathogens shed by infectious hosts to their environment. However, epidemiological models largely do not represent pathogen persistence outside the host explicitly. We hypothesize that this simplification might bias management-related model predictions for disease agents that can persist outside their host for a certain time span. We adapted an individual-based, spatially explicit epidemiological model that can mimic both transmission processes. One version explicitly simulated indirect pathogen transmission through a contaminated environment. A second version simulated direct host-to-host transmission only. We aligned the model variants by the transmission potential per infectious host (i.e. basic reproductive number R0 and the spatial transmission kernel of the infection to allow unbiased comparison of predictions. The quantitative model results are provided for the example of surveillance plans for early detection of foot-and-mouth disease in wild boar, a social host.We applied systematic sampling strategies on the serological status of randomly selected host individuals in both models. We compared between the model variants the time to detection and the area affected prior to detection, measures that strongly influence mitigation costs. Moreover, the ideal sampling strategy to detect the infection in a given time frame was compared between both models.We found the simplified, direct transmission model to underestimate necessary sample size by up to one order of magnitude, but to overestimate the area put under control measures. Thus, the model

  8. MRSA transmission between cows and humans

    NARCIS (Netherlands)

    Juhasz-Kaszanyitzky, E.; Janosi, S.; Somogyi, P.; Dan, A.; Graaf-van Bloois, van der L.; Dulijkeren, van E.; Wagenaar, J.A.

    2007-01-01

    We isolated methicillin-resistant Staphylococcus aureus (MRSA) from cows with subclinical mastitis and from a person who worked with these animals. The bovine and human strains were indistinguishable by phenotyping and genotyping methods and were of a low frequency spa type. To our knowledge, this

  9. Deterministic and stochastic CTMC models from Zika disease transmission

    Science.gov (United States)

    Zevika, Mona; Soewono, Edy

    2018-03-01

    Zika infection is one of the most important mosquito-borne diseases in the world. Zika virus (ZIKV) is transmitted by many Aedes-type mosquitoes including Aedes aegypti. Pregnant women with the Zika virus are at risk of having a fetus or infant with a congenital defect and suffering from microcephaly. Here, we formulate a Zika disease transmission model using two approaches, a deterministic model and a continuous-time Markov chain stochastic model. The basic reproduction ratio is constructed from a deterministic model. Meanwhile, the CTMC stochastic model yields an estimate of the probability of extinction and outbreaks of Zika disease. Dynamical simulations and analysis of the disease transmission are shown for the deterministic and stochastic models.

  10. Highly dynamic animal contact network and implications on disease transmission

    OpenAIRE

    Shi Chen; Brad J. White; Michael W. Sanderson; David E. Amrine; Amiyaal Ilany; Cristina Lanzas

    2014-01-01

    Contact patterns among hosts are considered as one of the most critical factors contributing to unequal pathogen transmission. Consequently, networks have been widely applied in infectious disease modeling. However most studies assume static network structure due to lack of accurate observation and appropriate analytic tools. In this study we used high temporal and spatial resolution animal position data to construct a high-resolution contact network relevant to infectious disease transmissio...

  11. Human transmissible spongiform encephalopathy: Case report

    Directory of Open Access Journals (Sweden)

    Duque Velásquez, Camilo

    2014-07-01

    Full Text Available We report the case of a 64 year-old woman with motor and cognitive deterioration that progressed rapidly during eight months. She was unsuccessfully treated with quinacrine, and died in a terminal status, by septic shock secondary to bronchopneumonia by broncho-aspiration. The brain was donated for research and the histopathological analysis showed spongiform changes, astrogliosis and prion protein (PrPRes deposits, confirmed by Western blot (WB. These features are considered characteristic of prion diseases, which are uncommon in Colombia. We highlight that its diagnosis was made for the first time in this country by the simultaneous use of immunohistochemistry and Western blot.

  12. Identifying Nodes of Transmission in Disease Diffusion Through Social Media

    Science.gov (United States)

    Lamb, David Sebastian

    The spread of infectious diseases can be described in terms of three interrelated components: interaction, movement, and scale. Transmission between individuals requires some form of interaction, which is dependent on the pathogen, to occur. Diseases spread through the movement of their hosts; they spread across many spatial scales from local neighborhoods to countries, or temporal scales from days to years, or periodic intervals. Prior research into the spread of disease have examined diffusion processes retrospectively at regional or country levels, or developed differential equation or simulation models of the dynamics of disease transmission. While some of the more recent models incorporate all three components, they are limited in the way they understand where interactions occur. The focus has been on home or work, including contact with family or coworkers. The models reflect a lack of knowledge about how transmissions are made at specific locations in time, so-called nodes of transmission. That is, how individuals' intersections in time and space function in disease transmission. This project sought to use the three factors of interaction, movement, and scale to better understand the spread of disease in terms of the place of interaction called the node of transmission. The overarching objective of this research was: how can nodes of transmission be identified through individual activity spaces incorporating the three factors of infectious disease spread: interaction, movement, and scale?. This objective fed into three main sub-objectives: defining nodes of transmission, developing an appropriate methodology to identifying nodes of transmission, and applying it using geotagged social media data from Twitter. To develop an appropriate framework, this research relied on time geography, and traditional disease. This particularly relied on the idea of bundling to create the nodes, and a nesting effect that integrated scale. The data source used to identify nodes

  13. Probable transmission of coxsackie B3 virus from human to chimpanzee, Denmark

    DEFF Research Database (Denmark)

    Nielsen, Sandra Cathrine Abel; Mourier, Tobias; Baandrup, Ulrik

    2012-01-01

    In 2010, a chimpanzee died at Copenhagen Zoo following an outbreak of respiratory disease among chimpanzees in the zoo. Identification of coxsackie B3 virus, a common human pathogen, as the causative agent, and its severe manifestation, raise questions about pathogenicity and transmissibility among...

  14. Efficient transmission and characterization of creutzfeldt-jakob disease strains in bank voles.

    Directory of Open Access Journals (Sweden)

    2006-02-01

    Full Text Available Transmission of prions between species is limited by the "species barrier," which hampers a full characterization of human prion strains in the mouse model. We report that the efficiency of primary transmission of prions from Creutzfeldt-Jakob disease patients to a wild rodent species, the bank vole (Clethrionomys glareolus, is comparable to that reported in transgenic mice carrying human prion protein, in spite of a low prion protein-sequence homology between man and vole. Voles infected with sporadic and genetic Creutzfeldt-Jakob disease isolates show strain-specific patterns of spongiform degeneration and pathological prion protein-deposition, and accumulate protease-resistant prion protein with biochemical properties similar to the human counterpart. Adaptation of genetic Creutzfeldt-Jakob disease isolates to voles shows little or no evidence of a transmission barrier, in contrast to the striking barriers observed during transmission of mouse, hamster, and sheep prions to voles. Our results imply that in voles there is no clear relationship between the degree of homology of the prion protein of the donor and recipient species and susceptibility, consistent with the view that the prion strain gives a major contribution to the species barrier. The vole is therefore a valuable model to study human prion diversity and, being susceptible to a range of animal prions, represents a unique tool for comparing isolates from different species.

  15. New Scenarios of Chagas Disease Transmission in Northern Colombia

    Directory of Open Access Journals (Sweden)

    Catalina Tovar Acero

    2017-01-01

    Full Text Available Chagas disease (CD is a systemic parasitic infection caused by the flagellated form of Trypanosoma cruzi. Córdoba department, located in the Colombian Caribbean Coast, was not considered as a region at risk of T. cruzi transmission. In this article, we describe the first acute CD case in Salitral village in Sahagún, Córdoba, confirmed by microscopy and serological tests. Our results draw attention to a new scenario of transmission of acute CD in nonendemic areas of Colombia and highlight the need to include CD in the differential diagnosis of febrile syndromes in this region.

  16. Weather Regulates Location, Timing, and Intensity of Dengue Virus Transmission between Humans and Mosquitoes.

    Science.gov (United States)

    Campbell, Karen M; Haldeman, Kristin; Lehnig, Chris; Munayco, Cesar V; Halsey, Eric S; Laguna-Torres, V Alberto; Yagui, Martín; Morrison, Amy C; Lin, Chii-Dean; Scott, Thomas W

    2015-01-01

    Dengue is one of the most aggressively expanding mosquito-transmitted viruses. The human burden approaches 400 million infections annually. Complex transmission dynamics pose challenges for predicting location, timing, and magnitude of risk; thus, models are needed to guide prevention strategies and policy development locally and globally. Weather regulates transmission-potential via its effects on vector dynamics. An important gap in understanding risk and roadblock in model development is an empirical perspective clarifying how weather impacts transmission in diverse ecological settings. We sought to determine if location, timing, and potential-intensity of transmission are systematically defined by weather. We developed a high-resolution empirical profile of the local weather-disease connection across Peru, a country with considerable ecological diversity. Applying 2-dimensional weather-space that pairs temperature versus humidity, we mapped local transmission-potential in weather-space by week during 1994-2012. A binary classification-tree was developed to test whether weather data could classify 1828 Peruvian districts as positive/negative for transmission and into ranks of transmission-potential with respect to observed disease. We show that transmission-potential is regulated by temperature-humidity coupling, enabling epidemics in a limited area of weather-space. Duration within a specific temperature range defines transmission-potential that is amplified exponentially in higher humidity. Dengue-positive districts were identified by mean temperature >22°C for 7+ weeks and minimum temperature >14°C for 33+ weeks annually with 95% sensitivity and specificity. In elevated-risk locations, seasonal peak-incidence occurred when mean temperature was 26-29°C, coincident with humidity at its local maximum; highest incidence when humidity >80%. We profile transmission-potential in weather-space for temperature-humidity ranging 0-38°C and 5-100% at 1°C x 2

  17. Weather Regulates Location, Timing, and Intensity of Dengue Virus Transmission between Humans and Mosquitoes.

    Directory of Open Access Journals (Sweden)

    Karen M Campbell

    Full Text Available Dengue is one of the most aggressively expanding mosquito-transmitted viruses. The human burden approaches 400 million infections annually. Complex transmission dynamics pose challenges for predicting location, timing, and magnitude of risk; thus, models are needed to guide prevention strategies and policy development locally and globally. Weather regulates transmission-potential via its effects on vector dynamics. An important gap in understanding risk and roadblock in model development is an empirical perspective clarifying how weather impacts transmission in diverse ecological settings. We sought to determine if location, timing, and potential-intensity of transmission are systematically defined by weather.We developed a high-resolution empirical profile of the local weather-disease connection across Peru, a country with considerable ecological diversity. Applying 2-dimensional weather-space that pairs temperature versus humidity, we mapped local transmission-potential in weather-space by week during 1994-2012. A binary classification-tree was developed to test whether weather data could classify 1828 Peruvian districts as positive/negative for transmission and into ranks of transmission-potential with respect to observed disease. We show that transmission-potential is regulated by temperature-humidity coupling, enabling epidemics in a limited area of weather-space. Duration within a specific temperature range defines transmission-potential that is amplified exponentially in higher humidity. Dengue-positive districts were identified by mean temperature >22°C for 7+ weeks and minimum temperature >14°C for 33+ weeks annually with 95% sensitivity and specificity. In elevated-risk locations, seasonal peak-incidence occurred when mean temperature was 26-29°C, coincident with humidity at its local maximum; highest incidence when humidity >80%. We profile transmission-potential in weather-space for temperature-humidity ranging 0-38°C and 5

  18. Deer density and disease prevalence influence transmission of Chronic Wasting Disease in White-tailed Deer

    Science.gov (United States)

    Samuel, Michael D.; Richards, Bryan J.; Storm, Daniel J.; Rolley, Robert E.; Shelton, Paul; Nicholas S. Keuler,; Timothy R. Van Deelen,

    2013-01-01

    Host-parasite dynamics and strategies for managing infectious diseases of wildlife depend on the functional relationship between disease transmission rates and host density. However, the disease transmission function is rarely known for free-living wildlife, leading to uncertainty regarding the impacts of diseases on host populations and effective control actions. We evaluated the influence of deer density, landscape features, and soil clay content on transmission of chronic wasting disease (CWD) in young (disease prevalence and density of infected deer, performed better than simple density- and frequency-dependent models. Our results indicate a combination of social structure, non-linear relationships between infectious contact and deer density, and distribution of disease among groups are important factors driving CWD infection in young deer. The landscape covariates % deciduous forest cover and forest edge density also were positively associated with infection rates, but soil clay content had no measurable influences on CWD transmission. Lack of strong density-dependent transmission rates indicates that controlling CWD by reducing deer density will be difficult. The consequences of non-linear disease transmission and aggregation of disease on cervid populations deserves further consideration.

  19. Efficient prion disease transmission through common environmental materials.

    Science.gov (United States)

    Pritzkow, Sandra; Morales, Rodrigo; Lyon, Adam; Concha-Marambio, Luis; Urayama, Akihiko; Soto, Claudio

    2018-03-02

    Prion diseases are a group of fatal neurodegenerative diseases associated with a protein-based infectious agent, termed prion. Compelling evidence suggests that natural transmission of prion diseases is mediated by environmental contamination with infectious prions. We hypothesized that several natural and man-made materials, commonly found in the environments of wild and captive animals, can bind prions and may act as vectors for disease transmission. To test our hypothesis, we exposed surfaces composed of various common environmental materials ( i.e. wood, rocks, plastic, glass, cement, stainless steel, aluminum, and brass) to hamster-adapted 263K scrapie prions and studied their attachment and retention of infectivity in vitro and in vivo Our results indicated that these surfaces, with the sole exception of brass, efficiently bind, retain, and release prions. Prion replication was studied in vitro using the protein misfolding cyclic amplification technology, and infectivity of surface-bound prions was analyzed by intracerebrally challenging hamsters with contaminated implants. Our results revealed that virtually all prion-contaminated materials transmitted the disease at high rates. To investigate a more natural form of exposure to environmental contamination, we simply housed animals with large contaminated spheres made of the different materials under study. Strikingly, most of the hamsters developed classical clinical signs of prion disease and typical disease-associated brain changes. Our findings suggest that prion contamination of surfaces commonly present in the environment can be a source of disease transmission, thus expanding our understanding of the mechanisms for prion spreading in nature. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Sheep movement networks and the transmission of infectious diseases.

    Directory of Open Access Journals (Sweden)

    Victoriya V Volkova

    2010-06-01

    Full Text Available Various approaches have been used to investigate how properties of farm contact networks impact on the transmission of infectious diseases. The potential for transmission of an infection through a contact network can be evaluated in terms of the basic reproduction number, R(0. The magnitude of R(0 is related to the mean contact rate of a host, in this case a farm, and is further influenced by heterogeneities in contact rates of individual hosts. The latter can be evaluated as the second order moments of the contact matrix (variances in contact rates, and co-variance between contacts to and from individual hosts. Here we calculate these quantities for the farms in a country-wide livestock network: >15,000 Scottish sheep farms in each of 4 years from July 2003 to June 2007. The analysis is relevant to endemic and chronic infections with prolonged periods of infectivity of affected animals, and uses different weightings of contacts to address disease scenarios of low, intermediate and high animal-level prevalence.Analysis of networks of Scottish farms via sheep movements from July 2003 to June 2007 suggests that heterogeneities in movement patterns (variances and covariances of rates of movement on and off the farms make a substantial contribution to the potential for the transmission of infectious diseases, quantified as R(0, within the farm population. A small percentage of farms (80% and these farms could be efficiently targeted by interventions aimed at reducing spread of diseases via animal movement.

  1. Transmission of antibiotic resistance from animals to humans

    NARCIS (Netherlands)

    Huijbers, P.M.C.

    2016-01-01

    Huijbers, P.M.C. (2016). Transmission of antibiotic resistance from animals to humans: Broilers as a reservoir of ESBL-producing bacteria. PhD thesis, Wageningen University, Wageningen, the Netherlands.

    Antibiotic resistance in animals becomes a public health issue when there is

  2. Virtual Elimination of Mother‑to‑Child Transmission of Human ...

    African Journals Online (AJOL)

    CD4 cell counts, and prolonged breastfeeding were implicated in MTCT of HIV in the era of ... of mother to child transmission (PMTCT) of human immunodeficiency virus (HIV), virtual elimination of mother to child ... The babies were tested for HIV using deoxyribo nucleic acid polymerase chain reaction test at 6 weeks, and ...

  3. Factors affecting the transmission of human onchocerciasis by ...

    African Journals Online (AJOL)

    The findings in this study, if corroborated with those of related studies based on parasitologic, ophthalmologic and socioeconomic monitoring will be useful for planning of effective treatments with ivermectin. Keywords: transmission, human onchocerciasis, savannah, Cross River State Mary Slessor Journal of Medicine Vol.

  4. Sexual transmission of human T-cell lymphotropic virus type 1

    Directory of Open Access Journals (Sweden)

    Arthur Paiva

    2014-06-01

    Full Text Available Human T-cell lymphotropic virus type 1 (HTLV-1 is endemic in many parts of the world and is primarily transmitted through sexual intercourse or from mother to child. Sexual transmission occurs more efficiently from men to women than women to men and might be enhanced by sexually transmitted diseases that cause ulcers and result in mucosal ruptures, such as syphilis, herpes simplex type 2 (HSV-2, and chancroid. Other sexually transmitted diseases might result in the recruitment of inflammatory cells and could increase the risk of HTLV-1 acquisition and transmission. Additionally, factors that are associated with higher transmission risks include the presence of antibodies against the viral oncoprotein Tax (anti-Tax, a higher proviral load in peripheral blood lymphocytes, and increased cervicovaginal or seminal secretions. Seminal fluid has been reported to increase HTLV replication and transmission, whereas male circumcision and neutralizing antibodies might have a protective effect. Recently, free virions were discovered in plasma, which reveals a possible new mode of HTLV replication. It is unclear how this discovery might affect the routes of HTLV transmission, particularly sexual transmission, because HTLV transmission rates are significantly higher from men to women than women to men.

  5. Transmission of infectious diseases en route to habitat hotspots.

    Science.gov (United States)

    Benavides, Julio; Walsh, Peter D; Meyers, Lauren Ancel; Raymond, Michel; Caillaud, Damien

    2012-01-01

    The spread of infectious diseases in wildlife populations is influenced by patterns of between-host contacts. Habitat "hotspots"--places attracting a large numbers of individuals or social groups--can significantly alter contact patterns and, hence, disease propagation. Research on the importance of habitat hotspots in wildlife epidemiology has primarily focused on how inter-individual contacts occurring at the hotspot itself increase disease transmission. However, in territorial animals, epidemiologically important contacts may primarily occur as animals cross through territories of conspecifics en route to habitat hotspots. So far, the phenomenon has received little attention. Here, we investigate the importance of these contacts in the case where infectious individuals keep visiting the hotspots and in the case where these individuals are not able to travel to the hotspot any more. We developed a simulation epidemiological model to investigate both cases in a scenario when transmission at the hotspot does not occur. We find that (i) hotspots still exacerbate epidemics, (ii) when infectious individuals do not travel to the hotspot, the most vulnerable individuals are those residing at intermediate distances from the hotspot rather than nearby, and (iii) the epidemiological vulnerability of a population is the highest when the number of hotspots is intermediate. By altering animal movements in their vicinity, habitat hotspots can thus strongly increase the spread of infectious diseases, even when disease transmission does not occur at the hotspot itself. Interestingly, when animals only visit the nearest hotspot, creating additional artificial hotspots, rather than reducing their number, may be an efficient disease control measure.

  6. A Systematic Review Regarding Tonometry and the Transmission of Infectious Diseases.

    Science.gov (United States)

    Atkins, Nicole; Hodge, William; Li, Bruce

    2018-03-01

    Tonometry has been identified as a common method for measuring the intraocular pressure in patients. The direct contact between the tonometer and the eye may contribute to the risk of cross infection, especially of viral particles, from one patient to another. A systematic review was undertaken to address the likelihood of human immunodeficiency virus (HIV), hepatitis B virus, hepatitis C virus, and prion diseases transmission through the use of tonometers. Additionally, a comparison of the current tonometer disinfection methods is provided to assist with identifying which technique effectively reduces the risk of disease transmission. An electronic literature search was conducted using the following databases: Web of Science, EMBASE, CINAHL, SCOPUS, Biosis Previews, Cochrane Library, PubMed, and Google Scholar. Dissertation indexes were also searched, and these included: Dissertations and Abstracts, and Dissertations and Abstracts - UK/Ireland. Additionally, the Clinicaltrials.gov trial registry was searched to identify any other relevant literature. Two independent reviewers critically appraised the articles retrieved through the literature search. In total, 11 unique studies were deemed relevant for this systematic review. The available evidence demonstrated that the use of tonometers contributes to the transmission of these infectious diseases in vitro . The results also demonstrated variability in determining the most effective tonometer sterilization technique against these infectious diseases in vitro . There was limited evidence available regarding the transmission of HIV, hepatitis B, hepatitis C, and prion diseases through the use of tonometers. Additionally, due to the variability regarding the most effective sterilization techniques, it is difficult to identify which sterilization technique is most effective or adequately effective against these infectious diseases. Future research studies regarding infectious disease transmission through tonometry and

  7. A Systematic Review Regarding Tonometry and the Transmission of Infectious Diseases

    Science.gov (United States)

    Atkins, Nicole; Hodge, William; Li, Bruce

    2018-01-01

    Tonometry has been identified as a common method for measuring the intraocular pressure in patients. The direct contact between the tonometer and the eye may contribute to the risk of cross infection, especially of viral particles, from one patient to another. A systematic review was undertaken to address the likelihood of human immunodeficiency virus (HIV), hepatitis B virus, hepatitis C virus, and prion diseases transmission through the use of tonometers. Additionally, a comparison of the current tonometer disinfection methods is provided to assist with identifying which technique effectively reduces the risk of disease transmission. An electronic literature search was conducted using the following databases: Web of Science, EMBASE, CINAHL, SCOPUS, Biosis Previews, Cochrane Library, PubMed, and Google Scholar. Dissertation indexes were also searched, and these included: Dissertations and Abstracts, and Dissertations and Abstracts - UK/Ireland. Additionally, the Clinicaltrials.gov trial registry was searched to identify any other relevant literature. Two independent reviewers critically appraised the articles retrieved through the literature search. In total, 11 unique studies were deemed relevant for this systematic review. The available evidence demonstrated that the use of tonometers contributes to the transmission of these infectious diseases in vitro. The results also demonstrated variability in determining the most effective tonometer sterilization technique against these infectious diseases in vitro. There was limited evidence available regarding the transmission of HIV, hepatitis B, hepatitis C, and prion diseases through the use of tonometers. Additionally, due to the variability regarding the most effective sterilization techniques, it is difficult to identify which sterilization technique is most effective or adequately effective against these infectious diseases. Future research studies regarding infectious disease transmission through tonometry and

  8. Is maternal transmission of coronary heart disease risk stronger than paternal transmission?

    Science.gov (United States)

    Kinra, S; Davey Smith, G; Okasha, M; McCarron, P; McEwen, J

    2003-08-01

    To test whether intergenerational transmission of coronary heart disease (CHD) to offspring is greater from the mother than from the father, the association between parental history of CHD and coronary mortality in male offspring was examined. Prospective cohort study with 43 years of follow up. University of Glasgow. Male students (n = 8402) aged 16-30 years when examined in 1948 to 1968. Fatal CHD. Of the 8402 men studied, 615 (7.3%) reported a history of CHD in at least one of the parents: 479 (5.8%) for fathers only, 124 (1.6%) for mothers only, and a further 12 (0.2%) for both their parents. During follow up, 373 (4.4%) men died of CHD. Parental history of disease was associated with fatal CHD and controlling for personal risk factors such as cigarette smoking, body mass index, systolic blood pressure, and father's social class did not attenuate this relation. The fully adjusted hazard ratios were 1.53 (95% confidence interval (CI) 1.08 to 2.18), 1.19 (95% CI 0.61 to 2.32), and 8.65 (95% CI 2.65 to 28.31) for father only, mother only, and both parents with CHD, respectively, compared with men whose parents did not have CHD. There was some evidence for interaction between parental histories (p = 0.049), with particularly high risk if both parents reported a history of CHD. This study found no differential transmission of CHD. Paternal history of CHD was at least as important as maternal history. Data from other comparable cohorts provide no consistent evidence of differential transmission. Intergenerational transmission of CHD does not appear to have differential effects between mothers and fathers.

  9. Transmission of chronic wasting disease in Wisconsin white-tailed deer: Implications for disease spread and management

    Science.gov (United States)

    Jennelle, Christopher S.; Henaux, Viviane; Wasserberg, Gideon; Thiagarajan, Bala; Rolley, Robert E.; Samuel, Michael D.

    2014-01-01

    Few studies have evaluated the rate of infection or mode of transmission for wildlife diseases, and the implications of alternative management strategies. We used hunter harvest data from 2002 to 2013 to investigate chronic wasting disease (CWD) infection rate and transmission modes, and address how alternative management approaches affect disease dynamics in a Wisconsin white-tailed deer population. Uncertainty regarding demographic impacts of CWD on cervid populations, human and domestic animal health concerns, and potential economic consequences underscore the need for strategies to control CWD distribution and prevalence. Using maximum-likelihood methods to evaluate alternative multi-state deterministic models of CWD transmission, harvest data strongly supports a frequency-dependent transmission structure with sex-specific infection rates that are two times higher in males than females. As transmissible spongiform encephalopathies are an important and difficult-to-study class of diseases with major economic and ecological implications, our work supports the hypothesis of frequency-dependent transmission in wild deer at a broad spatial scale and indicates that effective harvest management can be implemented to control CWD prevalence. Specifically, we show that harvest focused on the greater-affected sex (males) can result in stable population dynamics and control of CWD within the next 50 years, given the constraints of the model. We also provide a quantitative estimate of geographic disease spread in southern Wisconsin, validating qualitative assessments that CWD spreads relatively slowly. Given increased discovery and distribution of CWD throughout North America, insights from our study are valuable to management agencies and to the general public concerned about the impacts of CWD on white-tailed deer populations.

  10. Molecular insight into conformational transmission of human P-glycoprotein

    International Nuclear Information System (INIS)

    Chang, Shan-Yan; Liu, Fu-Feng; Dong, Xiao-Yan; Sun, Yan

    2013-01-01

    P-glycoprotein (P-gp), a kind of ATP-binding cassette transporter, can export candidates through a channel at the two transmembrane domains (TMDs) across the cell membranes using the energy released from ATP hydrolysis at the two nucleotide-binding domains (NBDs). Considerable evidence has indicated that human P-gp undergoes large-scale conformational changes to export a wide variety of anti-cancer drugs out of the cancer cells. However, molecular mechanism of the conformational transmission of human P-gp from the NBDs to the TMDs is still unclear. Herein, targeted molecular dynamics simulations were performed to explore the atomic detail of the conformational transmission of human P-gp. It is confirmed that the conformational transition from the inward- to outward-facing is initiated by the movement of the NBDs. It is found that the two NBDs move both on the two directions (x and y). The movement on the x direction leads to the closure of the NBDs, while the movement on the y direction adjusts the conformations of the NBDs to form the correct ATP binding pockets. Six key segments (KSs) protruding from the TMDs to interact with the NBDs are identified. The relative movement of the KSs along the y axis driven by the NBDs can be transmitted through α-helices to the rest of the TMDs, rendering the TMDs to open towards periplasm in the outward-facing conformation. Twenty eight key residue pairs are identified to participate in the interaction network that contributes to the conformational transmission from the NBDs to the TMDs of human P-gp. In addition, 9 key residues in each NBD are also identified. The studies have thus provided clear insight into the conformational transmission from the NBDs to the TMDs in human P-gp

  11. Modeling the transmission dynamics of Ebola virus disease in Liberia.

    Science.gov (United States)

    Xia, Zhi-Qiang; Wang, Shi-Fu; Li, Shen-Long; Huang, Liu-Yu; Zhang, Wen-Yi; Sun, Gui-Quan; Gai, Zhong-Tao; Jin, Zhen

    2015-09-08

    Ebola virus disease (EVD) has erupted many times in some zones since it was first found in 1976. The 2014 EVD outbreak in West Africa is the largest ever, which has caused a large number of deaths and the most serious country is Liberia during the outbreak period. Based on the data released by World Health Organization and the actual transmission situations, we investigate the impact of different transmission routes on the EVD outbreak in Liberia and estimate the basic reproduction number R0 = 2.012 in the absence of effective control measures. Through sensitivity and uncertainty analysis, we reveal that the transmission coefficients of suspected and probable cases have stronger correlations on the basic reproduction number. Furthermore, we study the influence of control measures (isolation and safe burial measures) on EVD outbreak. It is found that if combined control measures are taken, the basic reproduction number will be less than one and thus EVD in Liberia may be well contained. The obtained results may provide new guidance to prevent and control the spread of disease.

  12. Feeder density enhances house finch disease transmission in experimental epidemics.

    Science.gov (United States)

    Moyers, Sahnzi C; Adelman, James S; Farine, Damien R; Thomason, Courtney A; Hawley, Dana M

    2018-05-05

    Anthropogenic food provisioning of wildlife can alter the frequency of contacts among hosts and between hosts and environmental sources of pathogens. Despite the popularity of garden bird feeding, few studies have addressed how feeders influence host contact rates and disease dynamics. We experimentally manipulated feeder density in replicate aviaries containing captive, pathogen-naive, groups of house finches ( Haemorhous mexicanus ) and continuously tracked behaviours at feeders using radio-frequency identification devices. We then inoculated one bird per group with Mycoplasma gallisepticum (Mg), a common bacterial pathogen for which feeders are fomites of transmission, and assessed effects of feeder density on house finch behaviour and pathogen transmission. We found that pathogen transmission was significantly higher in groups with the highest density of bird feeders, despite a significantly lower rate of intraspecific aggressive interactions relative to the low feeder density groups. Conversely, among naive group members that never showed signs of disease, we saw significantly higher concentrations of Mg-specific antibodies in low feeder density groups, suggesting that birds in low feeder density treatments had exposure to subclinical doses of Mg. We discuss ways in which the density of garden bird feeders could play an important role in mediating the intensity of Mg epidemics.This article is part of the theme issue 'Anthropogenic resource subsidies and host-parasite dynamics in wildlife'. © 2018 The Author(s).

  13. Intermuscular force transmission between human plantarflexor muscles in vivo

    DEFF Research Database (Denmark)

    Bojsen-Møller, Jens; Schwartz, Sidse; Kalliokoski, Kari K

    2010-01-01

    of the present study was to investigate if intermuscular force transmission occurs within and between human plantarflexor muscles in vivo. Seven subjects performed four types of either active contractile tasks or passive joint manipulations: passive knee extension, voluntary isometric plantarflexion, voluntary...... surae muscles was seen during passive hallux extension. Large interindividual differences with respect to deep plantarflexor activation during voluntary contractions were observed. The present results suggest that force may be transmitted between the triceps surae muscles in vivo, while only limited...

  14. Possible impacts of sea level rise on disease transmission and potential adaptation strategies, a review.

    Science.gov (United States)

    Dvorak, Ana C; Solo-Gabriele, Helena M; Galletti, Andrea; Benzecry, Bernardo; Malone, Hannah; Boguszewski, Vicki; Bird, Jason

    2018-04-18

    Sea levels are projected to rise in response to climate change, causing the intrusion of sea water into land. In flat coastal regions, this would generate an increase in shallow water covered areas with limited circulation. This scenario raises a concern about the consequences it could have on human health, specifically the possible impacts on disease transmission. In this review paper we identified three categories of diseases which are associated with water and whose transmission can be affected by sea level rise. These categories include: mosquitoborne diseases, naturalized organisms (Vibrio spp. and toxic algae), and fecal-oral diseases. For each disease category, we propose comprehensive adaptation strategies that would help minimize possible health risks. Finally, the City of Key West, Florida is analyzed as a case study, due to its inherent vulnerability to sea level rise. Current and projected adaptation techniques are discussed as well as the integration of additional recommendations, focused on disease transmission control. Given that sea level rise will likely continue into the future, the promotion and implementation of positive adaptation strategies is necessary to ensure community resilience. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Hand, foot and mouth disease: spatiotemporal transmission and climate.

    Science.gov (United States)

    Wang, Jin-feng; Guo, Yan-Sha; Christakos, George; Yang, Wei-Zhong; Liao, Yi-Lan; Li, Zhong-Jie; Li, Xiao-Zhou; Lai, Sheng-Jie; Chen, Hong-Yan

    2011-04-05

    The Hand-Foot-Mouth Disease (HFMD) is the most common infectious disease in China, its total incidence being around 500,000~1,000,000 cases per year. The composite space-time disease variation is the result of underlining attribute mechanisms that could provide clues about the physiologic and demographic determinants of disease transmission and also guide the appropriate allocation of medical resources to control the disease. HFMD cases were aggregated into 1456 counties and during a period of 11 months. Suspected climate attributes to HFMD were recorded monthly at 674 stations throughout the country and subsequently interpolated within 1456 × 11 cells across space-time (same as the number of HFMD cases) using the Bayesian Maximum Entropy (BME) method while taking into consideration the relevant uncertainty sources. The dimensionalities of the two datasets together with the integrated dataset combining the two previous ones are very high when the topologies of the space-time relationships between cells are taken into account. Using a self-organizing map (SOM) algorithm the dataset dimensionality was effectively reduced into 2 dimensions, while the spatiotemporal attribute structure was maintained. 16 types of spatiotemporal HFMD transmission were identified, and 3-4 high spatial incidence clusters of the HFMD types were found throughout China, which are basically within the scope of the monthly climate (precipitation) types. HFMD propagates in a composite space-time domain rather than showing a purely spatial and purely temporal variation. There is a clear relationship between HFMD occurrence and climate. HFMD cases are geographically clustered and closely linked to the monthly precipitation types of the region. The occurrence of the former depends on the later.

  16. Optimizing agent-based transmission models for infectious diseases.

    Science.gov (United States)

    Willem, Lander; Stijven, Sean; Tijskens, Engelbert; Beutels, Philippe; Hens, Niel; Broeckhove, Jan

    2015-06-02

    Infectious disease modeling and computational power have evolved such that large-scale agent-based models (ABMs) have become feasible. However, the increasing hardware complexity requires adapted software designs to achieve the full potential of current high-performance workstations. We have found large performance differences with a discrete-time ABM for close-contact disease transmission due to data locality. Sorting the population according to the social contact clusters reduced simulation time by a factor of two. Data locality and model performance can also be improved by storing person attributes separately instead of using person objects. Next, decreasing the number of operations by sorting people by health status before processing disease transmission has also a large impact on model performance. Depending of the clinical attack rate, target population and computer hardware, the introduction of the sort phase decreased the run time from 26% up to more than 70%. We have investigated the application of parallel programming techniques and found that the speedup is significant but it drops quickly with the number of cores. We observed that the effect of scheduling and workload chunk size is model specific and can make a large difference. Investment in performance optimization of ABM simulator code can lead to significant run time reductions. The key steps are straightforward: the data structure for the population and sorting people on health status before effecting disease propagation. We believe these conclusions to be valid for a wide range of infectious disease ABMs. We recommend that future studies evaluate the impact of data management, algorithmic procedures and parallelization on model performance.

  17. Hand, foot and mouth disease: spatiotemporal transmission and climate

    Directory of Open Access Journals (Sweden)

    Li Xiao-Zhou

    2011-04-01

    Full Text Available Abstract Background The Hand-Foot-Mouth Disease (HFMD is the most common infectious disease in China, its total incidence being around 500,000 ~1,000,000 cases per year. The composite space-time disease variation is the result of underlining attribute mechanisms that could provide clues about the physiologic and demographic determinants of disease transmission and also guide the appropriate allocation of medical resources to control the disease. Methods and Findings HFMD cases were aggregated into 1456 counties and during a period of 11 months. Suspected climate attributes to HFMD were recorded monthly at 674 stations throughout the country and subsequently interpolated within 1456 × 11 cells across space-time (same as the number of HFMD cases using the Bayesian Maximum Entropy (BME method while taking into consideration the relevant uncertainty sources. The dimensionalities of the two datasets together with the integrated dataset combining the two previous ones are very high when the topologies of the space-time relationships between cells are taken into account. Using a self-organizing map (SOM algorithm the dataset dimensionality was effectively reduced into 2 dimensions, while the spatiotemporal attribute structure was maintained. 16 types of spatiotemporal HFMD transmission were identified, and 3-4 high spatial incidence clusters of the HFMD types were found throughout China, which are basically within the scope of the monthly climate (precipitation types. Conclusions HFMD propagates in a composite space-time domain rather than showing a purely spatial and purely temporal variation. There is a clear relationship between HFMD occurrence and climate. HFMD cases are geographically clustered and closely linked to the monthly precipitation types of the region. The occurrence of the former depends on the later.

  18. Characterizing the transmission dynamics and control of ebola virus disease.

    Directory of Open Access Journals (Sweden)

    Gerardo Chowell

    2015-01-01

    Full Text Available Carefully calibrated transmission models have the potential to guide public health officials on the nature and scale of the interventions required to control epidemics. In the context of the ongoing Ebola virus disease (EVD epidemic in Liberia, Drake and colleagues, in this issue of PLOS Biology, employed an elegant modeling approach to capture the distributions of the number of secondary cases that arise in the community and health care settings in the context of changing population behaviors and increasing hospital capacity. Their findings underscore the role of increasing the rate of safe burials and the fractions of infectious individuals who seek hospitalization together with hospital capacity to achieve epidemic control. However, further modeling efforts of EVD transmission and control in West Africa should utilize the spatial-temporal patterns of spread in the region by incorporating spatial heterogeneity in the transmission process. Detailed datasets are urgently needed to characterize temporal changes in population behaviors, contact networks at different spatial scales, population mobility patterns, adherence to infection control measures in hospital settings, and hospitalization and reporting rates.

  19. Insights into mechanisms of transmission and pathogenesis from transgenic mouse models of prion diseases

    Science.gov (United States)

    Moreno, Julie A.; Telling, Glenn C.

    2018-01-01

    Prions represent a new paradigm of protein-mediated information transfer. In the case of mammals, prions are the cause of fatal, transmissible neurodegenerative diseases, sometimes referred to as transmissible spongiform encephalopathies (TSE’s), which frequently occur as epidemics. An increasing body of evidence indicates that the canonical mechanism of conformational corruption of cellular prion protein (PrPC) by the pathogenic isoform (PrPSc) that is the basis of prion formation in TSE’s, is common to a spectrum of proteins associated with various additional human neurodegenerative disorders, including the more common Alzheimer’s and Parkinson’s diseases. The peerless infectious properties of TSE prions, and the unparalleled tools for their study, therefore enable elucidation of mechanisms of template-mediated conformational propagation that are generally applicable to these related disease states. Many unresolved issues remain including the exact molecular nature of the prion, the detailed cellular and molecular mechanisms of prion propagation, and the means by which prion diseases can be both genetic and infectious. In addition, we know little about the mechanism by which neurons degenerate during prion diseases. Tied to this, the physiological role of the normal form of the prion protein remains unclear and it is uncertain whether or not loss of this function contributes to prion pathogenesis. The factors governing the transmission of prions between species remain unclear, in particular the means by which prion strains and PrP primary structure interact to affect inter-species prion transmission. Despite all these unknowns, advances in our understanding of prions have occurred because of their transmissibility to experimental animals and the development of transgenic (Tg) mouse models has done much to further our understanding about various aspects of prion biology. In this review we will focus on advances in our understanding of prion biology that

  20. Transplacental transmission of Leishmania infantum as a means for continued disease incidence in North America.

    Science.gov (United States)

    Boggiatto, Paola Mercedes; Gibson-Corley, Katherine Nicole; Metz, Kyle; Gallup, Jack Michael; Hostetter, Jesse Michael; Mullin, Kathleen; Petersen, Christine Anne

    2011-04-12

    Dogs are the predominant domestic reservoir for human L. infantum infection. Zoonotic visceral leishmaniasis (ZVL) is an emerging problem in some U.S. dog breeds, with an annual quantitative PCR prevalence of greater than 20% within an at-risk Foxhound population. Although classically Leishmania is transmitted by infected sand flies and phlebotomine sand flies exist in the United States, means of ongoing L. infantum transmission in U.S. dogs is currently unknown. Possibilities include vertical (transplacental/transmammary) and horizontal/venereal transmission. Several reports have indicated that endemic ZVL may be transmitted vertically. Our aims for this present study were to establish whether vertical/transplacental transmission was occurring in this population of Leishmania-infected US dogs and determine the effect that this means of transmission has on immune recognition of Leishmania. A pregnant L. infantum-infected dam donated to Iowa State University gave birth in-house to 12 pups. Eight pups humanely euthanized at the time of birth and four pups and the dam humanely euthanized three months post-partum were studied via L. infantum-kinetoplast specific quantitative PCR (kqPCR), gross and histopathological assessment and CD4+ T cell proliferation assay. This novel report describes disseminated L. infantum parasites as identified by kqPCR in 8 day old pups born to a naturally-infected, seropositive U.S. dog with no travel history. This is the first report of vertical transmission of L. infantum in naturally-infected dogs in North America, emphasizing that this novel means of transmission could possibly sustain infection within populations. Evidence that vertical transmission of ZVL may be a driving force for ongoing disease in an otherwise non-endemic region has significant implications on current control strategies for ZVL, as at present parasite elimination efforts in endemic areas are largely focused on vector-borne transmission between canines and people

  1. Transplacental transmission of Leishmania infantum as a means for continued disease incidence in North America.

    Directory of Open Access Journals (Sweden)

    Paola Mercedes Boggiatto

    2011-04-01

    Full Text Available Dogs are the predominant domestic reservoir for human L. infantum infection. Zoonotic visceral leishmaniasis (ZVL is an emerging problem in some U.S. dog breeds, with an annual quantitative PCR prevalence of greater than 20% within an at-risk Foxhound population. Although classically Leishmania is transmitted by infected sand flies and phlebotomine sand flies exist in the United States, means of ongoing L. infantum transmission in U.S. dogs is currently unknown. Possibilities include vertical (transplacental/transmammary and horizontal/venereal transmission. Several reports have indicated that endemic ZVL may be transmitted vertically.Our aims for this present study were to establish whether vertical/transplacental transmission was occurring in this population of Leishmania-infected US dogs and determine the effect that this means of transmission has on immune recognition of Leishmania.A pregnant L. infantum-infected dam donated to Iowa State University gave birth in-house to 12 pups. Eight pups humanely euthanized at the time of birth and four pups and the dam humanely euthanized three months post-partum were studied via L. infantum-kinetoplast specific quantitative PCR (kqPCR, gross and histopathological assessment and CD4+ T cell proliferation assay.This novel report describes disseminated L. infantum parasites as identified by kqPCR in 8 day old pups born to a naturally-infected, seropositive U.S. dog with no travel history. This is the first report of vertical transmission of L. infantum in naturally-infected dogs in North America, emphasizing that this novel means of transmission could possibly sustain infection within populations.Evidence that vertical transmission of ZVL may be a driving force for ongoing disease in an otherwise non-endemic region has significant implications on current control strategies for ZVL, as at present parasite elimination efforts in endemic areas are largely focused on vector-borne transmission between canines

  2. Human transmissible spongiform encephalopathies in eleven countries: Diagnostic pattern across time, 1993-2002

    NARCIS (Netherlands)

    J. de Pedro-Cuesta (Jesús); M. Glatzel (Markus); J. Almazán (Javier); K. Stoeck (Katharina); V. Mellina (Vittorio); M. Puopolo (Maria); M. Pocchiari (Maurizio); I. Zerr (Inga); H.A. Kretszchmar (Hans); J-P. Brandel (Jean-Philippe); N. Delasnerie-Laupretre (Nicole); A. Alperovitch (Annick); C.M. van Duijn (Cornelia); P. Sanchez-Juan (Pascual); S.J. Collins (Steven); V. Lewis (Victoria); G.H. Jansen (Gerard); M.B. Coulthart (Michael); E. Gelpi (Ellen); H. Budka (Herbert); E. Mitrová (Eva)

    2006-01-01

    textabstractBackground: The objective of this study was to describe the diagnostic panorama of human transmissible spongiform encephalopathies across 11 countries. Methods: From data collected for surveillance purposes, we describe annual proportions of deaths due to different human transmissible

  3. Disease management mitigates risk of pathogen transmission from maricultured salmonids

    DEFF Research Database (Denmark)

    Jones, Simon R. M.; Bruno, David W.; Madsen, Lone

    2015-01-01

    that increased risk of exposure to neighbouring farms is inversely related to distance from and directly related to biomass at the source of infection. Epidemiological techniques integrating data from oceanography, diagnostics and pathogen shedding rates and viability contribute to improved understanding...... management thresholds. For wild populations, risk of pathogen spillback is estimated from farm-based epidemiological data; however, validation, particularly for ISAV and SAV, is required using direct surveillance....... of pathogen transmission pathways among farms and permit the designation of areas of risk associated with sources of infection. Occupation of an area of risk may increase the likelihood of exposure, infection and disease among susceptible fish. Disease mitigation in mariculture occurs at 2 scales: area...

  4. Possible transmission of HIV Infection due to human bite

    Directory of Open Access Journals (Sweden)

    Bandivdekar Atmaram H

    2011-03-01

    Full Text Available Abstract The potential risk of HIV-1 infection following human bite although epidemiologically insignificant, but it is biologically possible. There are anecdotal reports of HIV transmission by human bites particularly if saliva is mixed with blood. The oral tissues support HIV replication and may serve as a previously unrecognized HIV reservoir. The HIV infected individuals have more viruses in blood than saliva, possibly due to the potent HIV-inhibitory properties of saliva. The case presented here is of a primary HIV infections following a human bite where in the saliva was not blood stained but it got smeared on a raw nail bed of a recipient. The blood and saliva of the source and blood of the recipient showed a detectable viral load with 91% sequence homology of C2-V3 region of HIV gp120 between the two individuals. The recipient did not receive PEP [post exposure prophylaxis] as his family physician was unaware of salivary transmission. The family physician should have taken PEP decision after proper evaluation of the severe and bleeding bite. Hence it is necessary to treat the HIV infected human bites with post exposure prophylaxis.

  5. Transmission, Human Population, and Pathogenicity: the Ebola Case in Point.

    Science.gov (United States)

    Delgado, Rafael; Simón, Fernando

    2018-03-01

    The 2013-2016 Ebola outbreak in West Africa has been the largest ever of a known disease in a new context that produced an unprecedented impact and is changing the international approach to responding to public health emergencies. The unprecedented scale of the outbreak, the use of advanced technology for detecting and characterizing the infectious agent, along with the opportunity to treat patients in modern facilities have greatly increased our knowledge of the disease and its transmission. Also, for the first time, an important international effort has been deployed to control the spread of the epidemic by providing care to patients and by adopting basic measures of public health control. Apart from supportive treatment and intensive therapy with fluids and electrolytes, no new compounds have been proved to be clinically effective to treat Ebola virus disease; however, a specific vaccine has shown significant protection in clinical trials in Guinea, opening an expectation for controlling future outbreaks.

  6. Influenza as a human disease

    Indian Academy of Sciences (India)

    First page Back Continue Last page Graphics. Influenza as a human disease. Commonly perceived as a mild disease, affects every one, sometimes a couple of times in a year. Globally, seasonal influenza epidemics result in about three to five million yearly cases of severe illness and about 250,000 to 500,000 yearly ...

  7. Human communicable diseases

    International Nuclear Information System (INIS)

    2003-01-01

    The rising incidence of malaria and tuberculosis in sub-Saharan Africa is causing great hardship, not only to the individuals affected but also to the economies of the countries where they are rife. Both diseases are becoming more resistant to the drugs that are currently available for treatment and drug resistant strains are posing a global threat. The International Atomic Energy Agency (IAEA) is responding by sponsoring a programme to build technical competency in molecular and radioisotope-based techniques. (IAEA)

  8. Integrated Analysis of Environment, Cattle and Human Serological Data: Risks and Mechanisms of Transmission of Rift Valley Fever in Madagascar.

    Science.gov (United States)

    Olive, Marie-Marie; Chevalier, Véronique; Grosbois, Vladimir; Tran, Annelise; Andriamandimby, Soa-Fy; Durand, Benoit; Ravalohery, Jean-Pierre; Andriamamonjy, Seta; Rakotomanana, Fanjasoa; Rogier, Christophe; Heraud, Jean-Michel

    2016-07-01

    Rift Valley fever (RVF) is a vector-borne disease affecting ruminants and humans. Madagascar was heavily affected by RVF in 2008-2009, with evidence of a large and heterogeneous spread of the disease. The identification of at-risk environments is essential to optimize the available resources by targeting RVF surveillance in Madagascar. Herein, the objectives of our study were: (i) to identify the environmental factors and areas favorable to RVF transmission to both cattle and human and (ii) to identify human behaviors favoring human infections in Malagasy contexts. First, we characterized the environments of Malagasy communes using a Multiple Factor Analysis (MFA). Then, we analyzed cattle and human serological data collected at national level using Generalized Linear Mixed Models, with the individual serological status (cattle or human) as the response, and MFA factors, as well as other potential risk factors (cattle density, human behavior) as explanatory variables. Cattle and human seroprevalence rates were positively associated to humid environments (p<0.001). Areas with high cattle density were at risk (p<0.01; OR = 2.6). Furthermore, our analysis showed that frequent contact with raw milk contributed to explain human infection (OR = 1.6). Finally, our study highlighted the eastern-coast, western and north-western parts as high-risk areas for RVF transmission in cattle. Our integrated approach analyzing environmental, cattle and human datasets allow us to bring new insight on RVF transmission patterns in Madagascar. The association between cattle seroprevalence, humid environments and high cattle density suggests that concomitant vectorial and direct transmissions are critical to maintain RVF enzootic transmission. Additionally, in the at-risk humid environment of the western, north-western and the eastern-coast areas, suitable to Culex and Anopheles mosquitoes, vectorial transmission probably occurs in both cattle and human. The relative contribution of

  9. Integrated Analysis of Environment, Cattle and Human Serological Data: Risks and Mechanisms of Transmission of Rift Valley Fever in Madagascar.

    Directory of Open Access Journals (Sweden)

    Marie-Marie Olive

    2016-07-01

    Full Text Available Rift Valley fever (RVF is a vector-borne disease affecting ruminants and humans. Madagascar was heavily affected by RVF in 2008-2009, with evidence of a large and heterogeneous spread of the disease. The identification of at-risk environments is essential to optimize the available resources by targeting RVF surveillance in Madagascar. Herein, the objectives of our study were: (i to identify the environmental factors and areas favorable to RVF transmission to both cattle and human and (ii to identify human behaviors favoring human infections in Malagasy contexts.First, we characterized the environments of Malagasy communes using a Multiple Factor Analysis (MFA. Then, we analyzed cattle and human serological data collected at national level using Generalized Linear Mixed Models, with the individual serological status (cattle or human as the response, and MFA factors, as well as other potential risk factors (cattle density, human behavior as explanatory variables. Cattle and human seroprevalence rates were positively associated to humid environments (p<0.001. Areas with high cattle density were at risk (p<0.01; OR = 2.6. Furthermore, our analysis showed that frequent contact with raw milk contributed to explain human infection (OR = 1.6. Finally, our study highlighted the eastern-coast, western and north-western parts as high-risk areas for RVF transmission in cattle.Our integrated approach analyzing environmental, cattle and human datasets allow us to bring new insight on RVF transmission patterns in Madagascar. The association between cattle seroprevalence, humid environments and high cattle density suggests that concomitant vectorial and direct transmissions are critical to maintain RVF enzootic transmission. Additionally, in the at-risk humid environment of the western, north-western and the eastern-coast areas, suitable to Culex and Anopheles mosquitoes, vectorial transmission probably occurs in both cattle and human. The relative contribution

  10. 76 FR 58517 - Public Health Service Guideline for Reducing Transmission of Human Immunodeficiency Virus (HIV...

    Science.gov (United States)

    2011-09-21

    ...-2011-0011] Public Health Service Guideline for Reducing Transmission of Human Immunodeficiency Virus... public comment on the draft Public Health Service Guideline for Reducing Transmission of Human..., Attn: Public Health Service Guideline for Reducing Transmission of Human Immunodeficiency Virus (HIV...

  11. Human mobility and the spatial transmission of influenza in the United States

    DEFF Research Database (Denmark)

    Charu, Vivek; Zeger, Scott; Gog, Julia

    2017-01-01

    Seasonal influenza epidemics offer unique opportunities to study the invasion and re-invasion waves of a pathogen in a partially immune population. Detailed patterns of spread remain elusive, however, due to lack of granular disease data. Here we model high-volume city-level medical claims data...... and human mobility proxies to explore the drivers of influenza spread in the US during 2002–2010. Although the speed and pathways of spread varied across seasons, seven of eight epidemics likely originated in the Southern US. Each epidemic was associated with 1–5 early long-range transmission events, half...... of which sparked onward transmission. Gravity model estimates indicate a sharp decay in influenza transmission with the distance between infectious and susceptible cities, consistent with spread dominated by work commutes rather than air traffic. Two early-onset seasons associated with antigenic novelty...

  12. Viral diseases and human evolution

    Directory of Open Access Journals (Sweden)

    Leal Élcio de Souza

    2000-01-01

    Full Text Available The interaction of man with viral agents was possibly a key factor shaping human evolution, culture and civilization from its outset. Evidence of the effect of disease, since the early stages of human speciation, through pre-historical times to the present suggest that the types of viruses associated with man changed in time. As human populations progressed technologically, they grew in numbers and density. As a consequence different viruses found suitable conditions to thrive and establish long-lasting associations with man. Although not all viral agents cause disease and some may in fact be considered beneficial, the present situation of overpopulation, poverty and ecological inbalance may have devastating effets on human progress. Recently emerged diseases causing massive pandemics (eg., HIV-1 and HCV, dengue, etc. are becoming formidable challenges, which may have a direct impact on the fate of our species.

  13. Cohesin and Human Disease

    Science.gov (United States)

    Liu, Jinglan; Krantz, Ian D.

    2016-01-01

    Cornelia de Lange syndrome (CdLS) is a dominant multisystem disorder caused by a disruption of cohesin function. The cohesin ring complex is composed of four protein subunits and more than 25 additional proteins involved in its regulation. The discovery that this complex also has a fundamental role in long-range regulation of transcription in Drosophila has shed light on the mechanism likely responsible for its role in development. In addition to the three cohesin proteins involved in CdLS, a second multisystem, recessively inherited, developmental disorder, Roberts-SC phocomelia, is caused by mutations in another regulator of the cohesin complex, ESCO2. Here we review the phenotypes of these disorders, collectively termed cohesinopathies, as well as the mechanism by which cohesin disruption likely causes these diseases. PMID:18767966

  14. Human prion diseases in The Netherlands : clinico-pathological, genetic and molecular aspects

    NARCIS (Netherlands)

    Jansen, C.

    2011-01-01

    Prion diseases, or transmissible spongiform encephalopathies (TSEs), are invariably fatal neurodegenerative disorders that can be sporadic, inherited or acquired by infection. In humans, TSEs comprise three major groups showing a wide phenotypic heterogeneity: Creutzfeldt-Jakob disease (CJD),

  15. Prioritization of Companion Animal Transmissible Diseases for Policy Intervention in Europe.

    Science.gov (United States)

    Cito, F; Rijks, J; Rantsios, A T; Cunningham, A A; Baneth, G; Guardabassi, L; Kuiken, T; Giovannini, A

    2016-07-01

    A number of papers have been published on the prioritization of transmissible diseases in farm animals and wildlife, based either on semiquantitative or truly quantitative methods, but there is no published literature on the prioritization of transmissible diseases in companion animals. In this study, available epidemiological data for diseases transmissible from companion animals to man were analysed with the aim of developing a procedure suitable for their prioritization within a European framework. A new method and its associated questionnaire and scoring system were designed based on methods described by the World Organisation for Animal Health (OIE). Modifications were applied to allow for the paucity of specific information on companion animal transmissible diseases. The OIE method was also adapted to the subject and to the regional scope of the interprofessional network addressing zoonotic diseases transmitted via companion animals in Europe: the Companion Animals multisectoriaL interprofessionaL Interdisciplinary Strategic Think tank On zoonoses (CALLISTO). Adaptations were made based on information collected from expert groups on viral, bacterial and parasitic diseases using a structured questionnaire, in which all questions were closed-ended. The expert groups were asked to select the most appropriate answer for each question taking into account the relevance and reliability of the data available in the scientific literature. Subsequently, the scoring of the answers obtained for each disease covered by the questionnaire was analysed to obtain two final overall scores, one for human health impact and one for agricultural economic impact. The adapted method was then applied to select the 15 most important pathogens (five for each pathogen group: viral, bacterial and parasitic) on the basis of their overall impact on public health and agriculture. The result of the prioritization exercise was a joint priority list (available at www.callistoproject.eu) of

  16. Mathematical models for therapeutic approaches to control HIV disease transmission

    CERN Document Server

    Roy, Priti Kumar

    2015-01-01

    The book discusses different therapeutic approaches based on different mathematical models to control the HIV/AIDS disease transmission. It uses clinical data, collected from different cited sources, to formulate the deterministic as well as stochastic mathematical models of HIV/AIDS. It provides complementary approaches, from deterministic and stochastic points of view, to optimal control strategy with perfect drug adherence and also tries to seek viewpoints of the same issue from different angles with various mathematical models to computer simulations. The book presents essential methods and techniques for students who are interested in designing epidemiological models on HIV/AIDS. It also guides research scientists, working in the periphery of mathematical modeling, and helps them to explore a hypothetical method by examining its consequences in the form of a mathematical modelling and making some scientific predictions. The model equations, mathematical analysis and several numerical simulations that are...

  17. Human Immunodeficiency Virus (HIV types Western blot (WB band profiles as potential surrogate markers of HIV disease progression and predictors of vertical transmission in a cohort of infected but antiretroviral therapy naïve pregnant women in Harare, Zimbabwe

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    Chirenje Mike Z

    2011-01-01

    Full Text Available Abstract Background Expensive CD4 count and viral load tests have failed the intended objective of enabling access to HIV therapy in poor resource settings. It is imperative to develop simple, affordable and non-subjective disease monitoring tools to complement clinical staging efforts of inexperienced health personnel currently manning most healthcare centres because of brain drain. Besides accurately predicting HIV infection, sequential appearance of specific bands of WB test offers a window of opportunity to develop a less subjective tool for monitoring disease progression. Methods HIV type characterization was done in a cohort of infected pregnant women at 36 gestational weeks using WB test. Student-t test was used to determine maternal differences in mean full blood counts and viral load of mothers with and those without HIV gag antigen bands. Pearson Chi-square test was used to assess differences in lack of bands appearance with vertical transmission and lymphadenopathy. Results Among the 64 HIV infected pregnant women, 98.4% had pure HIV-1 infection and one woman (1.7% had dual HIV-1/HIV-2 infections. Absence of HIV pol antigen bands was associated with acute infection, p = 0.002. All women with chronic HIV-1 infection had antibody reactivity to both the HIV-1 envelope and polymerase antigens. However, antibody reactivity to gag antigens varied among the women, being 100%, 90%, 70% and 63% for p24, p17, p39 and p55, respectively. Lack of antibody reactivity to gag p39 antigen was associated with disease progression as confirmed by the presence of lymphadenopathy, anemia, higher viral load, p = 0.010, 0.025 and 0.016, respectively. Although not statistically significant, women with p39 band missing were 1.4 times more likely to transmit HIV-1 to their infants. Conclusion Absence of antibody reactivity to pol and gag p39 antigens was associated with acute infection and disease progression, respectively. Apart from its use in HIV disease

  18. Ecological Interactions between Humans, Wildlife Viral Reservoirs, and Key Environmental Drivers of Hantaan Virus Transmission

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    Xin Tong

    2017-10-01

    Full Text Available The occurrence and transmission of hemorrhagic fever with renal syndrome (HFRS are closely related to environmental variability, so it is essential to clarify the complex relationships among the environment, hantavirus transmission, and the population dynamics of its wildlife hosts. Tian et al. analyzed a large, long-term dataset describing the circulation of hantavirus in rodents and its spillover into humans. Their article incorporates several mathematical models and argues that the interaction between environmental and human behavioral factors drives the observed seasonality and interannual variations in important zoonotic diseases. The ecological cascade effect of a drought in 2002 is highlighted, and the role of seasonality in agricultural activity is emphasized in that study.

  19. Creutzfeldt-Jakob disease lookback study: 21 years of surveillance for transfusion transmission risk.

    Science.gov (United States)

    Crowder, Lauren A; Schonberger, Lawrence B; Dodd, Roger Y; Steele, Whitney R

    2017-08-01

    Transfusion transmission of human prion diseases has been observed for variant Creutzfeldt-Jakob disease (vCJD), but not for the classic forms of prion disease (CJD: sporadic, genetic, and iatrogenic). Although the presence of prions or misfolded prion proteins in blood has been documented in some patients with the most common form of CJD, sporadic CJD, no transfusion-transmitted cases of CJD have been recognized. Since 1995, the American Red Cross has conducted a lookback study of the recipients of blood products from donors who develop CJD to assess the risk of blood-borne CJD transmission in the United States. Blood donors subsequently diagnosed with confirmed or probable CJD were enrolled and the consignees were asked to identify the recipients of their blood products. These donors' transfusion recipients are traced annually with the National Death Index to see if they subsequently die of CJD. To date, 65 CJD donors have been enrolled along with 826 of their blood recipients. These recipients have contributed 3934 person-years of follow-up and no transfusion-transmitted cases of CJD have been recognized. From this study, as well as other epidemiologic studies, there is no evidence of CJD transfusion transmission; this risk remains theoretical. © 2017 AABB.

  20. Meat and bone meal and mineral feed additives may increase the risk of oral prion disease transmission

    Science.gov (United States)

    Johnson, Christopher J.; McKenzie, Debbie; Pedersen, Joel A.; Aiken, Judd M.

    2011-01-01

    Ingestion of prion-contaminated materials is postulated to be a primary route of prion disease transmission. Binding of prions to soil (micro)particles dramatically enhances peroral disease transmission relative to unbound prions, and it was hypothesized that micrometer-sized particles present in other consumed materials may affect prion disease transmission via the oral route of exposure. Small, insoluble particles are present in many substances, including soil, human foods, pharmaceuticals, and animal feeds. It is known that meat and bone meal (MBM), a feed additive believed responsible for the spread of bovine spongiform encephalopathy (BSE), contains particles smaller than 20 μm and that the pathogenic prion protein binds to MBM. The potentiation of disease transmission via the oral route by exposure to MBM or three micrometer-sized mineral feed additives was determined. Data showed that when the disease agent was bound to any of the tested materials, the penetrance of disease was increased compared to unbound prions. Our data suggest that in feed or other prion-contaminated substances consumed by animals or, potentially, humans, the addition of MBM or the presence of microparticles could heighten risks of prion disease acquisition.

  1. Lumped parametric model of the human ear for sound transmission.

    Science.gov (United States)

    Feng, Bin; Gan, Rong Z

    2004-09-01

    A lumped parametric model of the human auditoria peripherals consisting of six masses suspended with six springs and ten dashpots was proposed. This model will provide the quantitative basis for the construction of a physical model of the human middle ear. The lumped model parameters were first identified using published anatomical data, and then determined through a parameter optimization process. The transfer function of the middle ear obtained from human temporal bone experiments with laser Doppler interferometers was used for creating the target function during the optimization process. It was found that, among 14 spring and dashpot parameters, there were five parameters which had pronounced effects on the dynamic behaviors of the model. The detailed discussion on the sensitivity of those parameters was provided with appropriate applications for sound transmission in the ear. We expect that the methods for characterizing the lumped model of the human ear and the model parameters will be useful for theoretical modeling of the ear function and construction of the ear physical model.

  2. Urban transmission of Chagas disease in Cochabamba, Bolivia

    Directory of Open Access Journals (Sweden)

    N Medrano-Mercado

    2008-08-01

    Full Text Available Chagas disease is a major public health problem in Bolivia. In the city of Cochabamba, 58% of the population lives in peripheral urban districts ("popular zones" where the infection prevalence is extremely high. From 1995 to 1999, we studied the demographics of Chagas infections in children from five to 13 years old (n = 2218 from the South zone (SZ and North zone (NZ districts, which differ in social, environmental, and agricultural conditions. Information gathered from these districts demonstrates qualitative and quantitative evidence for the active transmission of Trypanosoma cruzi in urban Cochabamba. Seropositivity was high in both zones (25% in SZ and 19% in NZ. We observed a high risk of infection in children from five to nine years old in SZ, but in NZ, a higher risk occurred in children aged 10-13, with odds ratio for infection three times higher in NZ than in SZ. This difference was not due to triatomine density, since more than 1,000 Triatoma infestans were captured in both zones, but was possibly secondary to the vector infection rate (79% in SZ and 37% in NZ. Electrocardiogram abnormalities were found to be prevalent in children and pre-adolescents (SZ = 40%, NZ = 17%, indicating that under continuous exposure to infection and re-infection, a severe form of the disease may develop early in life. This work demonstrates that T. cruzi infection should also be considered an urban health problem and is not restricted to the rural areas and small villages of Bolivia.

  3. Spatial analysis of visceral leishmaniasis in the municipality of Rondonópolis, in the Brazilian State of Mato Grosso, from 2003 to 2012: human, canine and vector distribution in areas of disease transmission

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    Alexander Gonçalves Ferreira Guimarães

    2015-06-01

    Full Text Available INTRODUCTION: Visceral leishmaniasis (VL is a zoonosis of great importance to public health and is considered a neglected disease by the World Health Organization. The disease has expanded and become more prevalent in urban areas in Brazil. METHODS: Geospatial analyses were performed and thematic maps of the triad of the disease were produced for the study period (2003-2012 in the urban area of the municipality of Rondonópolis in the midwestern State of Mato Grosso (MT, Brazil, TerraView 4.2.2 software was used for the analyses. RESULTS: A total of 87.9% of the 186 confirmed human cases of VL were cured. Children between the ages of 1 and 4 were the most affected. Registered deaths were predominant among adults aged 60 years or older. The urban area of the municipality consists of eight strata and 12 census districts include 237 neighborhoods. All sectors had confirmed cases of VL. During the study period, human cases of the disease were recorded in 90 neighborhoods. The 23 deaths from the disease were distributed in 21 neighborhoods. Sandflies carrying the parasite were captured in 192 out of 200 neighborhoods evaluated for the presence of the VL vector. The presence of dogs carrying the parasite was confirmed in, 140 out of 154 surveyed neighborhoods. CONCLUSIONS: The data demonstrated the endemic nature of VL, with a high percentage of infected children, a high distribution of canine infection, and a wide adaptation and dispersal of the vectors in the urban environment. These results, illustrate the process of urbanization of VL in the municipality of Rondonópolis, MT, Brazil.

  4. Some considerations concerning the challenge of incorporating social variables into epidemiological models of infectious disease transmission.

    Science.gov (United States)

    Barnett, Tony; Fournié, Guillaume; Gupta, Sunetra; Seeley, Janet

    2015-01-01

    Incorporation of 'social' variables into epidemiological models remains a challenge. Too much detail and models cease to be useful; too little and the very notion of infection - a highly social process in human populations - may be considered with little reference to the social. The French sociologist Émile Durkheim proposed that the scientific study of society required identification and study of 'social currents'. Such 'currents' are what we might today describe as 'emergent properties', specifiable variables appertaining to individuals and groups, which represent the perspectives of social actors as they experience the environment in which they live their lives. Here we review the ways in which one particular emergent property, hope, relevant to a range of epidemiological situations, might be used in epidemiological modelling of infectious diseases in human populations. We also indicate how such an approach might be extended to include a range of other potential emergent properties to represent complex social and economic processes bearing on infectious disease transmission.

  5. Dynamics of host-reservoir transmission of Ebola with spillover potential to humans

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    Berge Tsanou

    2018-04-01

    Full Text Available Ebola virus disease (EVD is a zoonotic borne disease (i.e. disease that is spread from animals to people. Therefore human beings can be infected through direct contact with an infected animal (fruit-eating bat or great ape. It has been demonstrated that fruit-eating bats of pteropodidae family are potential reservoir of EVD. Moreover, it has been biologically shown that fruit-eating bats do not die due to EVD and bear the Ebola viruses lifelong. We develop in this paper, a mathematical model to assess the impact of the reservoir on the dynamics of EVD. Our model couples a bat-to-bat model with a human-to-human model and the indirect environmental contamination through a spillover process (i.e. process by which a zoonotic pathogen moves (regardless of transmission mode from an animal host (or environmental reservoir to a human host from bats to humans. The sub-models and the coupled models exhibit each a threshold behavior with the corresponding basic reproduction numbers being the bifurcation parameters. Existence of equilibria, their global stability are established by combining monotone operator theory, Lyapunov-LaSalle techniques and graph theory. Control strategies are assessed by using the target reproduction numbers. The efforts required to control EVD are assessed as well through S-control. The spillover event is shown to be highly detrimental to EVD by allowing the disease to switch from bats to humans even though the disease was not initially endemic in the human population. Precisely, we show that the spillover phenomenon contributes to speed up the disease outbreak. This suggests that the manipulation and consumption of fruit-bats play an important role in sustaining EVD in a given environment.

  6. Co-feeding transmission facilitates strain coexistence in Borrelia burgdorferi, the Lyme disease agent

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    S.L. States

    2017-06-01

    Full Text Available Coexistence of multiple tick-borne pathogens or strains is common in natural hosts and can be facilitated by resource partitioning of the host species, within-host localization, or by different transmission pathways. Most vector-borne pathogens are transmitted horizontally via systemic host infection, but transmission may occur in the absence of systemic infection between two vectors feeding in close proximity, enabling pathogens to minimize competition and escape the host immune response. In a laboratory study, we demonstrated that co-feeding transmission can occur for a rapidly-cleared strain of Borrelia burgdorferi, the Lyme disease agent, between two stages of the tick vector Ixodes scapularis while feeding on their dominant host, Peromyscus leucopus. In contrast, infections rapidly became systemic for the persistently infecting strain. In a field study, we assessed opportunities for co-feeding transmission by measuring co-occurrence of two tick stages on ears of small mammals over two years at multiple sites. Finally, in a modeling study, we assessed the importance of co-feeding on R0, the basic reproductive number. The model indicated that co-feeding increases the fitness of rapidly-cleared strains in regions with synchronous immature tick feeding. Our results are consistent with increased diversity of B. burgdorferi in areas of higher synchrony in immature feeding – such as the midwestern United States. A higher relative proportion of rapidly-cleared strains, which are less human pathogenic, would also explain lower Lyme disease incidence in this region. Finally, if co-feeding transmission also occurs on refractory hosts, it may facilitate the emergence and persistence of new pathogens with a more limited host range.

  7. Estimation of the transmission of foot-and-mouth disease virus from infected sheep to cattle

    NARCIS (Netherlands)

    Bravo De Rueda, C.; Jong, de M.C.M.; Eble, P.L.; Dekker, A.

    2014-01-01

    The quantitative role of sheep in the transmission of foot-and-mouth disease virus (FMDV) is not well known. To estimate the role of sheep in the transmission of FMDV, a direct contact transmission experiment with 10 groups of animals each consisting of 2 infected lambs and 1 contact calf was

  8. Infectious prion diseases in humans: cannibalism, iatrogenicity and zoonoses.

    Science.gov (United States)

    Haïk, Stéphane; Brandel, Jean-Philippe

    2014-08-01

    In contrast with other neurodegenerative disorders associated to protein misfolding, human prion diseases include infectious forms (also called transmitted forms) such as kuru, iatrogenic Creutzfeldt-Jakob disease and variant Creutzfeldt-Jakob disease. The transmissible agent is thought to be solely composed of the abnormal isoform (PrP(Sc)) of the host-encoded prion protein that accumulated in the central nervous system of affected individuals. Compared to its normal counterpart, PrP(Sc) is β-sheet enriched and aggregated and its propagation is based on an autocatalytic conversion process. Increasing evidence supports the view that conformational variations of PrP(Sc) encoded the biological properties of the various prion strains that have been isolated by transmission studies in experimental models. Infectious forms of human prion diseases played a pivotal role in the emergence of the prion concept and in the characterization of the very unconventional properties of prions. They provide a unique model to understand how prion strains are selected and propagate in humans. Here, we review and discuss how genetic factors interplay with strain properties and route of transmission to influence disease susceptibility, incubation period and phenotypic expression in the light of the kuru epidemics due to ritual endocannibalism, the various series iatrogenic diseases secondary to extractive growth hormone treatment or dura mater graft and the epidemics of variant Creutzfeldt-Jakob disease linked to dietary exposure to the agent of bovine spongiform encephalopathy. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Simulating the spread of malaria using a generic transmission model for mosquito-borne infectious diseases

    Science.gov (United States)

    Kon, Cynthia Mui Lian; Labadin, Jane

    2016-06-01

    Malaria is a critical infection caused by parasites which are spread to humans through mosquito bites. Approximately half of the world's population is in peril of getting infected by malaria. Mosquito-borne diseases have a standard behavior where they are transmitted in the same manner, only through vector mosquito. Taking this into account, a generic spatial-temporal model for transmission of multiple mosquito-borne diseases had been formulated. Our interest is to reproduce the actual cases of different mosquito-borne diseases using the generic model and then predict future cases so as to improve control and target measures competently. In this paper, we utilize notified weekly malaria cases in four districts in Sarawak, Malaysia, namely Kapit, Song, Belaga and Marudi. The actual cases for 36 weeks, which is from week 39 in 2012 to week 22 in 2013, are compared with simulations of the generic spatial-temporal transmission mosquito-borne diseases model. We observe that the simulation results display corresponding result to the actual malaria cases in the four districts.

  10. Early animal farming and zoonotic disease dynamics: modelling brucellosis transmission in Neolithic goat populations.

    Science.gov (United States)

    Fournié, Guillaume; Pfeiffer, Dirk U; Bendrey, Robin

    2017-02-01

    Zoonotic pathogens are frequently hypothesized as emerging with the origins of farming, but evidence of this is elusive in the archaeological records. To explore the potential impact of animal domestication on zoonotic disease dynamics and human infection risk, we developed a model simulating the transmission of Brucella melitensis within early domestic goat populations. The model was informed by archaeological data describing goat populations in Neolithic settlements in the Fertile Crescent, and used to assess the potential of these populations to sustain the circulation of Brucella . Results show that the pathogen could have been sustained even at low levels of transmission within these domestic goat populations. This resulted from the creation of dense populations and major changes in demographic characteristics. The selective harvesting of young male goats, likely aimed at improving the efficiency of food production, modified the age and sex structure of these populations, increasing the transmission potential of the pathogen within these populations. Probable interactions between Neolithic settlements would have further promoted pathogen maintenance. By fostering conditions suitable for allowing domestic goats to become reservoirs of Brucella melitensis , the early stages of agricultural development were likely to promote the exposure of humans to this pathogen.

  11. Proteins aggregation and human diseases

    Science.gov (United States)

    Hu, Chin-Kun

    2015-04-01

    Many human diseases and the death of most supercentenarians are related to protein aggregation. Neurodegenerative diseases include Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), frontotemporallobar degeneration, etc. Such diseases are due to progressive loss of structure or function of neurons caused by protein aggregation. For example, AD is considered to be related to aggregation of Aβ40 (peptide with 40 amino acids) and Aβ42 (peptide with 42 amino acids) and HD is considered to be related to aggregation of polyQ (polyglutamine) peptides. In this paper, we briefly review our recent discovery of key factors for protein aggregation. We used a lattice model to study the aggregation rates of proteins and found that the probability for a protein sequence to appear in the conformation of the aggregated state can be used to determine the temperature at which proteins can aggregate most quickly. We used molecular dynamics and simple models of polymer chains to study relaxation and aggregation of proteins under various conditions and found that when the bending-angle dependent and torsion-angle dependent interactions are zero or very small, then protein chains tend to aggregate at lower temperatures. All atom models were used to identify a key peptide chain for the aggregation of insulin chains and to find that two polyQ chains prefer anti-parallel conformation. It is pointed out that in many cases, protein aggregation does not result from protein mis-folding. A potential drug from Chinese medicine was found for Alzheimer's disease.

  12. Transmission Properties of Human PrP 102L Prions Challenge the Relevance of Mouse Models of GSS.

    Science.gov (United States)

    Asante, Emmanuel A; Grimshaw, Andrew; Smidak, Michelle; Jakubcova, Tatiana; Tomlinson, Andrew; Jeelani, Asif; Hamdan, Shyma; Powell, Caroline; Joiner, Susan; Linehan, Jacqueline M; Brandner, Sebastian; Wadsworth, Jonathan D F; Collinge, John

    2015-07-01

    Inherited prion disease (IPD) is caused by autosomal-dominant pathogenic mutations in the human prion protein (PrP) gene (PRNP). A proline to leucine substitution at PrP residue 102 (P102L) is classically associated with Gerstmann-Sträussler-Scheinker (GSS) disease but shows marked clinical and neuropathological variability within kindreds that may be caused by variable propagation of distinct prion strains generated from either PrP 102L or wild type PrP. To-date the transmission properties of prions propagated in P102L patients remain ill-defined. Multiple mouse models of GSS have focused on mutating the corresponding residue of murine PrP (P101L), however murine PrP 101L, a novel PrP primary structure, may not have the repertoire of pathogenic prion conformations necessary to accurately model the human disease. Here we describe the transmission properties of prions generated in human PrP 102L expressing transgenic mice that were generated after primary challenge with ex vivo human GSS P102L or classical CJD prions. We show that distinct strains of prions were generated in these mice dependent upon source of the inoculum (either GSS P102L or CJD brain) and have designated these GSS-102L and CJD-102L prions, respectively. GSS-102L prions have transmission properties distinct from all prion strains seen in sporadic and acquired human prion disease. Significantly, GSS-102L prions appear incapable of transmitting disease to conventional mice expressing wild type mouse PrP, which contrasts strikingly with the reported transmission properties of prions generated in GSS P102L-challenged mice expressing mouse PrP 101L. We conclude that future transgenic modeling of IPDs should focus exclusively on expression of mutant human PrP, as other approaches may generate novel experimental prion strains that are unrelated to human disease.

  13. Defining the Risk of Zika and Chikungunya Virus Transmission in Human Population Centers of the Eastern United States.

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    Carrie A Manore

    2017-01-01

    Full Text Available The recent spread of mosquito-transmitted viruses and associated disease to the Americas motivates a new, data-driven evaluation of risk in temperate population centers. Temperate regions are generally expected to pose low risk for significant mosquito-borne disease; however, the spread of the Asian tiger mosquito (Aedes albopictus across densely populated urban areas has established a new landscape of risk. We use a model informed by field data to assess the conditions likely to facilitate local transmission of chikungunya and Zika viruses from an infected traveler to Ae. albopictus and then to other humans in USA cities with variable human densities and seasonality. Mosquito-borne disease occurs when specific combinations of conditions maximize virus-to-mosquito and mosquito-to-human contact rates. We develop a mathematical model that captures the epidemiology and is informed by current data on vector ecology from urban sites. The model demonstrates that under specific but realistic conditions, fifty-percent of introductions by infectious travelers to a high human, high mosquito density city could initiate local transmission and 10% of the introductions could result in 100 or more people infected. Despite the propensity for Ae. albopictus to bite non-human vertebrates, we also demonstrate that local virus transmission and human outbreaks may occur when vectors feed from humans even just 40% of the time. Inclusion of human behavioral changes and mitigations were not incorporated into the models and would likely reduce predicted infections. This work demonstrates how a conditional series of non-average events can result in local arbovirus transmission and outbreaks of human disease, even in temperate cities.

  14. Possible iatrogenic transmission of Creutzfeldt-Jakob disease via tonometer tips: a review of the literature.

    Science.gov (United States)

    Walia, J S; Chronister, C L

    2001-10-01

    Tonometer tips are used by optometrists to measure intraocular pressures. The recommended procedure of soaking in bleach solution kills bacteria and certain viruses, such as human immunodeficiency virus, herpes simplex virus-1 and herpes simplex virus-2, adenovirus 8, and hepatitis B, from the tip. Conversely, recommendations made in literature to sterilize equipment that may have come in contact with virus-contaminated tissue from patients with Creutzfeldt-Jakob disease have a somewhat tougher requirement. Autoclaving for 1 hour at a temperature of at least 120 degrees C (15 psi), or a 1-hour exposure to 0.5% sodium hypochlorite (a 10-fold dilution of household bleach) should provide excellent disinfection. One-hour exposure to 1 N Sodium hydroxide has also been mentioned in the literature. Studies have shown that corneas of guinea pigs with Cruetzfeldt-Jakob disease (C-J disease) are infectious. Infected corneas have been shown to cause transmission via corneal transplants, and via experimental placement of infected guinea pig's cornea into the anterior chamber of uninfected guinea pigs. Many researchers have strongly suggested that C-J disease can be iatrogenically transmitted via applanation tonometer tips. An epidemiologic case-controlled study found statistically significant odds ratio for intraocular pressure testing in the medical history of patients with C-J disease. Even though there have not been any proven studies confirming iatrogenic transmission through tonometer tips, optometrists should be cautious if a patient has C-J disease, or manifests symptoms of C-J disease and use alternatives to Goldmann applanation tonometry.

  15. The effect of vector control strategy against Dengue transmission between mosquitoes and humans

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    Chen-Xia Yang

    2017-03-01

    Full Text Available With the consideration of mechanism of prevention and control for the spread of dengue fever, a mathematical model of dengue fever dynamical transmission between mosquitoes and humans, incorporating a vector control strategy of impulsive culling of mosquitoes, is proposed in this paper. By using the comparison principle, Floquet theorem and some of analytical methods, we obtain the basic reproductive number $\\mathcal{R}_0$ for this infectious disease, which illustrates the stability of the disease-free periodic solution and the uniform persistence of the disease. Further, the explicit conditions determining the backward or forward bifurcation are obtained and the culling rate $\\phi$ is a major effect on the occurrence of backward bifurcation. Finally, numerical simulations are given to verify the correctness of theoretical results and the most efficiency of vector control strategy.

  16. Quantification of Foot-and-mouth Disease Virus Transmission Rates Using Published Data

    NARCIS (Netherlands)

    Goris, N.E.; Eble, P.L.; Jong, de M.C.M.; Clercq, K.

    2009-01-01

    Foot-and-mouth disease is an extremely infectious and devastating disease affecting all species of cloven-hoofed animals. To understand the epidemiology of the causative virus and predict viral transmission dynamics, quantified transmission parameters are essential to decision makers and modellers

  17. Transmission scenarios of major vector-borne diseases in Colombia, 1990-2016

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    Julio César Padilla

    2017-03-01

    Conclusions: Persistent epidemic and endemic transmission of vector-borne diseases in urban and rural settings in Colombia was observed mainly in the case of malaria, dengue, leishmaniasis and Chagas disease. Such transmission was focused and had variable intensity patterns. On the other hand, the conditions that have favored the emergence of new arboviruses persist.

  18. Transfer RNA and human disease

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    Jamie A Abbott

    2014-06-01

    Full Text Available Pathological mutations in tRNA genes and tRNA processing enzymes are numerous and result in very complicated clinical phenotypes. Mitochondrial tRNA (mt-tRNA genes are hotspots for pathological mutations and over 200 mt-tRNA mutations have been linked to various disease states. Often these mutations prevent tRNA aminoacylation. Disrupting this primary function affects protein synthesis and the expression, folding, and function of oxidative phosphorylation enzymes. Mitochondrial tRNA mutations manifest in a wide panoply of diseases related to cellular energetics, including COX deficiency (cytochrome C oxidase, mitochondrial myopathy, MERRF (Myoclonic Epilepsy with Ragged Red Fibers, and MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. Diseases caused by mt-tRNA mutations can also affect very specific tissue types, as in the case of neurosensory non-syndromic hearing loss and pigmentary retinopathy, diabetes mellitus, and hypertrophic cardiomyopathy. Importantly, mitochondrial heteroplasmy plays a role in disease severity and age of onset as well. Not surprisingly, mutations in enzymes that modify cytoplasmic and mitochondrial tRNAs are also linked to a diverse range of clinical phenotypes. In addition to compromised aminoacylation of the tRNAs, mutated modifying enzymes can also impact tRNA expression and abundance, tRNA modifications, tRNA folding, and even tRNA maturation (e.g., splicing. Some of these pathological mutations in tRNAs and processing enzymes are likely to affect non-canonical tRNA functions, and contribute to the diseases without significantly impacting on translation. This chapter will review recent literature on the relation of mitochondrial and cytoplasmic tRNA, and enzymes that process tRNAs, to human disease. We explore the mechanisms involved in the clinical presentation of these various diseases with an emphasis on neurological disease.

  19. Transfer RNA and human disease.

    Science.gov (United States)

    Abbott, Jamie A; Francklyn, Christopher S; Robey-Bond, Susan M

    2014-01-01

    Pathological mutations in tRNA genes and tRNA processing enzymes are numerous and result in very complicated clinical phenotypes. Mitochondrial tRNA (mt-tRNA) genes are "hotspots" for pathological mutations and over 200 mt-tRNA mutations have been linked to various disease states. Often these mutations prevent tRNA aminoacylation. Disrupting this primary function affects protein synthesis and the expression, folding, and function of oxidative phosphorylation enzymes. Mitochondrial tRNA mutations manifest in a wide panoply of diseases related to cellular energetics, including COX deficiency (cytochrome C oxidase), mitochondrial myopathy, MERRF (Myoclonic Epilepsy with Ragged Red Fibers), and MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes). Diseases caused by mt-tRNA mutations can also affect very specific tissue types, as in the case of neurosensory non-syndromic hearing loss and pigmentary retinopathy, diabetes mellitus, and hypertrophic cardiomyopathy. Importantly, mitochondrial heteroplasmy plays a role in disease severity and age of onset as well. Not surprisingly, mutations in enzymes that modify cytoplasmic and mitochondrial tRNAs are also linked to a diverse range of clinical phenotypes. In addition to compromised aminoacylation of the tRNAs, mutated modifying enzymes can also impact tRNA expression and abundance, tRNA modifications, tRNA folding, and even tRNA maturation (e.g., splicing). Some of these pathological mutations in tRNAs and processing enzymes are likely to affect non-canonical tRNA functions, and contribute to the diseases without significantly impacting on translation. This chapter will review recent literature on the relation of mitochondrial and cytoplasmic tRNA, and enzymes that process tRNAs, to human disease. We explore the mechanisms involved in the clinical presentation of these various diseases with an emphasis on neurological disease.

  20. Proteins aggregation and human diseases

    International Nuclear Information System (INIS)

    Hu, Chin-Kun

    2015-01-01

    Many human diseases and the death of most supercentenarians are related to protein aggregation. Neurodegenerative diseases include Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), frontotemporallobar degeneration, etc. Such diseases are due to progressive loss of structure or function of neurons caused by protein aggregation. For example, AD is considered to be related to aggregation of Aβ40 (peptide with 40 amino acids) and Aβ42 (peptide with 42 amino acids) and HD is considered to be related to aggregation of polyQ (polyglutamine) peptides. In this paper, we briefly review our recent discovery of key factors for protein aggregation. We used a lattice model to study the aggregation rates of proteins and found that the probability for a protein sequence to appear in the conformation of the aggregated state can be used to determine the temperature at which proteins can aggregate most quickly. We used molecular dynamics and simple models of polymer chains to study relaxation and aggregation of proteins under various conditions and found that when the bending-angle dependent and torsion-angle dependent interactions are zero or very small, then protein chains tend to aggregate at lower temperatures. All atom models were used to identify a key peptide chain for the aggregation of insulin chains and to find that two polyQ chains prefer anti-parallel conformation. It is pointed out that in many cases, protein aggregation does not result from protein mis-folding. A potential drug from Chinese medicine was found for Alzheimer's disease. (paper)

  1. Risks of Zoonosic Disease transmission in pets in Sancti Spíritus City.

    Directory of Open Access Journals (Sweden)

    Odmara M. Castellanos Yero

    2012-06-01

    Full Text Available For the development of this work the urban zone of Sancti Spíritus was taken as a sample. The main objective was to identify the risk factors associated to the ignorance of zoonosis transmitted by pet animals. The tests were applied to 50 homes in 5 People’s Council, having as a total 250 housings. Dogs were the animals which predominated in houses (66.6%.The risks of Zoonosis showed that 393 persons are in direct contact with the animals, 330 played with them and 234 bathe them. The 64.0 % of the persons that were tested knew about the risk of animals for the human health, the lowest knowledge was obtained in the People’s Council of kilo 12 and Jesus Maria. Tested persons agreed that animals have lowest risk of transmitting disease to human. The 62 % of tested persons said that the most common way of zoonosic disease transmission is by bites. For the tested population the most known zoonosic diseases were: Leptospirosis, Brucellosis, Rabia and Salmonellosis, the population showed great desire for being training about zoonosic diseases, giving more responsibility in this task to Veterinarian Service (75.2 %.

  2. Mycobacterium avium complex--the role of potable water in disease transmission.

    Science.gov (United States)

    Whiley, H; Keegan, A; Giglio, S; Bentham, R

    2012-08-01

    Mycobacterium avium complex (MAC) is a group of opportunistic pathogens of major public health concern. It is responsible for a wide spectrum of disease dependent on subspecies, route of infection and patients pre-existing conditions. Presently, there is limited research on the incidence of MAC infection that considers both pulmonary and other clinical manifestations. MAC has been isolated from various terrestrial and aquatic environments including natural waters, engineered water systems and soils. Identifying the specific environmental sources responsible for human infection is essential in minimizing disease prevalence. This paper reviews current literature and case studies regarding the wide spectrum of disease caused by MAC and the role of potable water in disease transmission. Potable water was recognized as a putative pathway for MAC infection. Contaminated potable water sources associated with human infection included warm water distribution systems, showers, faucets, household drinking water, swimming pools and hot tub spas. MAC can maintain long-term contamination of potable water sources through its high resistance to disinfectants, association with biofilms and intracellular parasitism of free-living protozoa. Further research is required to investigate the efficiency of water treatment processes against MAC and into construction and maintenance of warm water distribution systems and the role they play in MAC proliferation. No claim to Australian Government works Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  3. Atlas of Mexican Triatominae (Reduviidae: Hemiptera) and vector transmission of Chagas disease

    Science.gov (United States)

    Ramsey, Janine M; Peterson, A Townsend; Carmona-Castro, Oscar; Moo-Llanes, David A; Nakazawa, Yoshinori; Butrick, Morgan; Tun-Ku, Ezequiel; de la Cruz-Félix, Keynes; Ibarra-Cerdeña, Carlos N

    2015-01-01

    Chagas disease is one of the most important yet neglected parasitic diseases in Mexico and is transmitted by Triatominae. Nineteen of the 31 Mexican triatomine species have been consistently found to invade human houses and all have been found to be naturally infected with Trypanosoma cruzi. The present paper aims to produce a state-of-knowledge atlas of Mexican triatomines and analyse their geographic associations with T. cruzi, human demographics and landscape modification. Ecological niche models (ENMs) were constructed for the 19 species with more than 10 records in North America, as well as for T. cruzi. The 2010 Mexican national census and the 2007 National Forestry Inventory were used to analyse overlap patterns with ENMs. Niche breadth was greatest in species from the semiarid Nearctic Region, whereas species richness was associated with topographic heterogeneity in the Neotropical Region, particularly along the Pacific Coast. Three species, Triatoma longipennis, Triatoma mexicana and Triatoma barberi, overlapped with the greatest numbers of human communities, but these communities had the lowest rural/urban population ratios. Triatomine vectors have urbanised in most regions, demonstrating a high tolerance to human-modified habitats and broadened historical ranges, exposing more than 88% of the Mexican population and leaving few areas in Mexico without the potential for T. cruzi transmission. PMID:25993505

  4. Atlas of Mexican Triatominae (Reduviidae: Hemiptera and vector transmission of Chagas disease

    Directory of Open Access Journals (Sweden)

    Janine M Ramsey

    2015-05-01

    Full Text Available Chagas disease is one of the most important yet neglected parasitic diseases in Mexico and is transmitted by Triatominae. Nineteen of the 31 Mexican triatomine species have been consistently found to invade human houses and all have been found to be naturally infected with Trypanosoma cruzi. The present paper aims to produce a state-of-knowledge atlas of Mexican triatomines and analyse their geographic associations with T. cruzi, human demographics and landscape modification. Ecological niche models (ENMs were constructed for the 19 species with more than 10 records in North America, as well as for T. cruzi. The 2010 Mexican national census and the 2007 National Forestry Inventory were used to analyse overlap patterns with ENMs. Niche breadth was greatest in species from the semiarid Nearctic Region, whereas species richness was associated with topographic heterogeneity in the Neotropical Region, particularly along the Pacific Coast. Three species, Triatoma longipennis, Triatoma mexicana and Triatoma barberi, overlapped with the greatest numbers of human communities, but these communities had the lowest rural/urban population ratios. Triatomine vectors have urbanised in most regions, demonstrating a high tolerance to human-modified habitats and broadened historical ranges, exposing more than 88% of the Mexican population and leaving few areas in Mexico without the potential for T. cruzi transmission.

  5. AIDS e doenças oportunistas transmissíveis na faixa de fronteira Brasileira AIDS and transmissible opportunistic diseases in the Brazilian border area

    Directory of Open Access Journals (Sweden)

    Antonio Luiz Rodrigues-Júnior

    2010-10-01

    Full Text Available INTRODUÇÃO: A transmissão do HIV e de outras doenças transmissíveis, de pessoa a pessoa, pode ser associada à mobilidade humana. Este trabalho avaliou a incidência de doenças oportunistas transmissíveis entre os casos de AIDS, nos municípios da faixa de fronteira brasileira. MÉTODOS: Os municípios da faixa de fronteira brasileira foram agrupados em três regiões culturais; foram consideradas as notificações feitas ao Ministério da Saúde, entre 1990 e 2003, que tenham sido feitas com os critérios de definição CDC adaptado, Rio de Janeiro/Caracas e óbito; as doenças oportunistas detectadas foram agrupadas de acordo com o tipo de transmissão: 1 inalação do agente; 2 ingestão de água/alimento contaminado e 3 contato interpessoal. A análise descritiva considerou regiões culturais, anos de escolaridade, categoria de transmissão, sexo e faixa etária. RESULTADOS: Houve diferentes padrões de incidência de AIDS nos grupos de doenças oportunistas em cada região cultural. A região extremo-sul apresentou a maior incidência de AIDS; o número de casos de AIDS do sexo feminino foi maior na categoria heterossexual; o número de casos de AIDS do sexo masculino foi maior entre usuários de drogas injetáveis; as doenças transmitidas pelo contato interpessoal foram as mais frequentes, destacando a incidência de monilíases; a tuberculose e a pneumonia foram as mais frequentes dentre as doenças transmitidas pela inalação do agente; as doenças transmitidas pela ingestão de água/alimentos contaminados mostraram um padrão de incidência estável. CONCLUSÕES: A fronteira brasileira é um espaço geográfico importante e heterogêneo; o enfrentamento da AIDS deve reconhecer as diferentes geografias culturais.INTRODUCTION: Person-to-person transmission of HIV and other communicable diseases may be associated with human geographic mobility. This article evaluated the incidence of transmissible opportunistic diseases among

  6. Pregnancy and transmission of Human Immunodefiency Virus (HIV ...

    African Journals Online (AJOL)

    Background: Serodiscordant couples, have been used to study heterosexual transmission risk because of the high frequency of sexual acts that occur in stable relationships. The hormonal changes during pregnancy could influence heterosexual transmission in serodiscordant relationships. The prevalence of ...

  7. Impact of Public Safety Policies on Human Immunodeficiency Virus Transmission Dynamics in Tijuana, Mexico.

    Science.gov (United States)

    Mehta, Sanjay R; Chaillon, Antoine; Gaines, Tommi L; Gonzalez-Zuniga, Patricia E; Stockman, Jamila K; Almanza-Reyes, Horatio; Chavez, Jose Roman; Vera, Alicia; Wagner, Karla D; Patterson, Thomas L; Scott, Brianna; Smith, Davey M; Strathdee, Steffanie A

    2018-02-10

    North Tijuana, Mexico is home to many individuals at high risk for transmitting and acquiring human immunodeficiency virus (HIV). Recently, policy shifts by local government impacted how these individuals were handled by authorities. Here we examined how this affected regional HIV transmission dynamics. HIV pol sequences and associated demographic information were collected from 8 research studies enrolling persons in Tijuana and were used to infer viral transmission patterns. To evaluate the impact of recent policy changes on HIV transmission dynamics, qualitative interviews were performed on a subset of recently infected individuals. Between 2004 and 2016, 288 unique HIV pol sequences were obtained from individuals in Tijuana, including 46.4% from men who have sex with men, 42.1% from individuals reporting transactional sex, and 27.8% from persons who inject drugs (some individuals had >1 risk factor). Forty-two percent of sequences linked to at least 1 other sequence, forming 37 transmission clusters. Thirty-two individuals seroconverted during the observation period, including 8 between April and July 2016. Three of these individuals were putatively linked together. Qualitative interviews suggested changes in policing led individuals to shift locations of residence and injection drug use, leading to increased risk taking (eg, sharing needles). Near real-time molecular epidemiologic analyses identified a cluster of linked transmissions temporally associated with policy shifts. Interviews suggested these shifts may have led to increased risk taking among individuals at high risk for HIV acquisition. With all public policy shifts, downstream impacts need to be carefully considered, as even well-intentioned policies can have major public health consequences. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

  8. The contribution of social behaviour to the transmission of influenza A in a human population.

    Science.gov (United States)

    Kucharski, Adam J; Kwok, Kin O; Wei, Vivian W I; Cowling, Benjamin J; Read, Jonathan M; Lessler, Justin; Cummings, Derek A; Riley, Steven

    2014-06-01

    Variability in the risk of transmission for respiratory pathogens can result from several factors, including the intrinsic properties of the pathogen, the immune state of the host and the host's behaviour. It has been proposed that self-reported social mixing patterns can explain the behavioural component of this variability, with simulated intervention studies based on these data used routinely to inform public health policy. However, in the absence of robust studies with biological endpoints for individuals, it is unclear how age and social behaviour contribute to infection risk. To examine how the structure and nature of social contacts influenced infection risk over the course of a single epidemic, we designed a flexible disease modelling framework: the population was divided into a series of increasingly detailed age and social contact classes, with the transmissibility of each age-contact class determined by the average contacts of that class. Fitting the models to serologically confirmed infection data from the 2009 Hong Kong influenza A/H1N1p pandemic, we found that an individual's risk of infection was influenced strongly by the average reported social mixing behaviour of their age group, rather than by their personal reported contacts. We also identified the resolution of social mixing that shaped transmission: epidemic dynamics were driven by intense contacts between children, a post-childhood drop in risky contacts and a subsequent rise in contacts for individuals aged 35-50. Our results demonstrate that self-reported social contact surveys can account for age-associated heterogeneity in the transmission of a respiratory pathogen in humans, and show robustly how these individual-level behaviours manifest themselves through assortative age groups. Our results suggest it is possible to profile the social structure of different populations and to use these aggregated data to predict their inherent transmission potential.

  9. AIDS and transmissible opportunistic diseases in the Brazilian border area

    OpenAIRE

    RODRIGUES-JÚNIOR, Antonio Luiz; CASTILHO, Euclides Ayres de

    2010-01-01

    INTRODUÇÃO: A transmissão do HIV e de outras doenças transmissíveis, de pessoa a pessoa, pode ser associada à mobilidade humana. Este trabalho avaliou a incidência de doenças oportunistas transmissíveis entre os casos de AIDS, nos municípios da faixa de fronteira brasileira. MÉTODOS: Os municípios da faixa de fronteira brasileira foram agrupados em três regiões culturais; foram consideradas as notificações feitas ao Ministério da Saúde, entre 1990 e 2003, que tenham sido feitas com os critéri...

  10. Defining sporadic Creutzfeldt-Jakob disease strains and their transmission properties

    Science.gov (United States)

    Bishop, Matthew T.; Will, Robert G.; Manson, Jean C.

    2010-01-01

    The biological determinants of the phenotypic variation in sporadic Creutzfeldt-Jakob disease (sCJD) are unknown. To categorize sCJD cases, the prion protein (PrP) codon 129 genotype and the biochemical characteristics of the disease-associated form of PrP (PrPSc) can be combined to form six subgroups (MM1, MM2, MV1, MV2, VV1, and VV2). This classification largely correlates with the known variation in the clinical and pathological features of sCJD, with the MM1 and MV1 cases representing the “classic” phenotype of sCJD. To address how this classification relates to different strains of sCJD we have inoculated each subgroup of sCJD to a panel of mice expressing different forms of the human PRNP gene (129MM, 129VV, and 129MV). We have established that all subtypes are transmissible to at least one genotype of mouse, and both agent and host factors determine transmission efficiency and the form of PrPSc deposited in the brain. Moreover, we have identified four distinct strains of sCJD using our in vivo strain typing panel. PMID:20547859

  11. Self-propagative replication of Aβ oligomers suggests potential transmissibility in Alzheimer disease.

    Directory of Open Access Journals (Sweden)

    Amit Kumar

    Full Text Available The aggregation of amyloid-β (Aβ peptide and its deposition in parts of the brain form the central processes in the etiology of Alzheimer disease (AD. The low-molecular weight oligomers of Aβ aggregates (2 to 30 mers are known to be the primary neurotoxic agents whose mechanisms of cellular toxicity and synaptic dysfunction have received substantial attention in the recent years. However, how these toxic agents proliferate and induce widespread amyloid deposition throughout the brain, and what mechanism is involved in the amplification and propagation of toxic oligomer species, are far from clear. Emerging evidence based on transgenic mice models indicates a transmissible nature of Aβ aggregates and implicates a prion-like mechanism of oligomer propagation, which manifests as the dissemination and proliferation of Aβ toxicity. Despite accumulating evidence in support of a transmissible nature of Aβ aggregates, a clear, molecular-level understanding of this intriguing mechanism is lacking. Recently, we reported the characterization of unique replicating oligomers of Aβ42 (12-24 mers in vitro called Large Fatty Acid-derived Oligomers (LFAOs (Kumar et al., 2012, J. Biol. Chem. In the current report, we establish that LFAOs possess physiological activity by activating NF-κB in human neuroblastoma cells, and determine the experimental parameters that control the efficiency of LFAO replication by self-propagation. These findings constitute the first detailed report on monomer - oligomer lateral propagation reactions that may constitute potential mechanism governing transmissibility among Aβ oligomers. These data support the previous reports on transmissible mechanisms observed in transgenic animal models.

  12. Multinational corporations and infectious disease: Embracing human rights management techniques.

    Science.gov (United States)

    Salcito, Kendyl; Singer, Burton H; Weiss, Mitchell G; Winkler, Mirko S; Krieger, Gary R; Wielga, Mark; Utzinger, Jürg

    2014-01-01

    by companies, governments and civil society provides a roadmap for engaging business enterprises in rights-based disease management strategies to mitigate disease transmission rates and improve human welfare outcomes.

  13. Multiple mechanisms of transmission of the Caribbean coral disease white plague

    Science.gov (United States)

    Clemens, E.; Brandt, M. E.

    2015-12-01

    White plague is one of the most devastating coral diseases in the Caribbean, and yet important aspects of its epidemiology, including how the disease transmits, remain unknown. This study tested potential mechanisms and rates of transmission of white plague in a laboratory setting. Transmission mechanisms including the transport of water, contact with macroalgae, and predation via corallivorous worms and snails were tested on the host species Orbicella annularis. Two of the tested mechanisms were shown to transmit disease: water transport and the corallivorous snail Coralliophila abbreviata. Between these transmission mechanisms, transport of water between a diseased coral and a healthy coral resulted in disease incidence significantly more frequently in exposed healthy corals. Transmission via water transport also occurred more quickly and was associated with higher rates of tissue loss (up to 3.5 cm d-1) than with the corallivorous snail treatment. In addition, water that was in contact with diseased corals but was filtered with a 0.22-μm filter prior to being introduced to apparently healthy corals also resulted in the transmission of disease signs, but at a much lower rate than when water was not filtered. This study has provided important information on the transmission potential of Caribbean white plague disease and highlights the need for a greater understanding of how these processes operate in the natural environment.

  14. ROUTES OF TRANSMISSION OF DISEASES IN DENTAL PRACTICE

    African Journals Online (AJOL)

    Department of Community and Preventive Dentistry. Faculty of Dentistry, Muhimbili University College of Health Sciences,. Dar es Salaam, Tanzania. Contamination and infection. Transmission of microorganisms ego bacteria, viruses; fungi and protozoa is a hazard in dental practice (1-4) .. Introduction of microorganisms.

  15. No between-pen transmission of foot-and-mouth disease virus in vaccinated pigs

    NARCIS (Netherlands)

    Roermund, van H.J.W.; Eblé, P.L.; Jong, de M.C.M.; Dekker, A.

    2010-01-01

    Many studies have shown transmission of foot-and-mouth disease virus (FMDV) within groups of pigs, even when vaccinated, but only limited information is available on transmission between pens. Three new experiments were carried out in two replicates, which consisted of infectious pigs housed in a

  16. Aerosol transmission of foot-and-mouth disease virus Asia-1 under experimental conditions

    NARCIS (Netherlands)

    Colenutt, C.; Gonzales, J.L.; Paton, D.J.; Gloster, J.; Nelson, N.; Sanders, C.

    2016-01-01

    Foot-and-mouth disease virus (FMDV) control measures rely on understanding of virus transmission mechanisms. Direct contact between naïve and infected animals or spread by contaminated fomites is prevented by quarantines and rigorous decontamination procedures during outbreaks. Transmission of

  17. [Anorectal manifestations of sexually transmissible diseases. Kaposi's sarcoma].

    Science.gov (United States)

    Libeskind, M; Malbran, J; Agard, D; Pannetier, C; Lecouillard, C; Ivanovic, A

    1984-01-01

    The proctologist is above all concerned with the known recrudescence of venereal diseases. Examples reviewed are diseases of bacterial origin (syphilis, gonorrhea, soft chancre, donovanosis and chlamydiosis), appropriate antibiotic therapy and diseases of viral origin (herpes, condyloma acuminatum). Also noted are other bacterial, viral and parasitic diseases and, indeed, cancers of which Kaposi's sarcoma is the example, even though these are not manifested anorectally. New data on Kaposi's sarcoma, its' relationships with venereal disease and AIDS are presented. With these complex problems, the central role of male homosexuality and lowered cellular immunity widens considerably the professional scope of the proctologist.

  18. Attributing the human disease burden of foodborne infections to specific sources.

    NARCIS (Netherlands)

    Pires, S.M.; Evers, E.G.; van Pelt, W.; Ayers, T.; Scallan, E.; Angulo, F.J.; Havelaar, A.H.; Hald, T.

    2009-01-01

    Foodborne diseases are an important cause of human illness worldwide. Humans acquire these infections from a variety of sources and routes of transmission. Many efforts have been made in the last decades to prevent and control foodborne diseases, particularly foodborne zoonoses. However, information

  19. Attributing the Human Disease Burden of Foodborne Infections to Specific Sources

    DEFF Research Database (Denmark)

    Pires, Sara Monteiro; Evers, Eric E.; Van Pely, Wilfrid

    2009-01-01

    Foodborne diseases are an important cause of human illness worldwide. Humans acquire these infections from a variety of sources and routes of transmission. Many efforts have been made in the last decades to prevent and control foodborne diseases, particularly foodborne zoonoses. However...

  20. Modeling freshwater snail habitat suitability and areas of potential snail-borne disease transmission in Uganda

    DEFF Research Database (Denmark)

    Stensgaard, Anna-Sofie; Jørgensen, Aslak; Kabatereine, N B

    2006-01-01

    -borne disease transmission areas. Furthermore, knowledge of abiotic factors affecting intra-molluscan parasitic development can be used to make "masks" based on remotely sensed climatic data, and these can in turn be used to refine these predictions. We used data from a recent freshwater snail survey from......Geographic information system (GIS-based modeling of an intermediate host snail species environmental requirements using known occurrence records can provide estimates of its spatial distribution. When other data are lacking, this can be used as a rough spatial prediction of potential snail...... Uganda, environmental data and the genetic algorithm for rule-set prediction (GARP) to map the potential distribution of snail species known to act as intermediate hosts of several human and animal parasites. The results suggest that large areas of Uganda are suitable habitats for many of these snail...

  1. Transmission of hazardous diseases via nanobacterial contamination of medical and dental equipment

    Directory of Open Access Journals (Sweden)

    Jafar Kolahi

    2013-01-01

    Full Text Available Introduction: Nanobacteria (calcifying nanoparticles, nanobes are one of the most controversial issues in contemporary biology. Studies show accumulating evidence on association of nanobacteria with pathologic calcifications such as kidney stone, arterial plaque, calcification of coronary arteries, and cardiac valves calculus. The Hypothesis: Nanobacteria can tolerate harsh conditions extremely well. The apatite mineral layer around the organism and slow metabolism is likely to be the reason for the resistance of nanobacteria. They showed a wide resistance to the several disinfecting and sterilizating chemicals as well as autoclaving, ultraviolet light, microwaves, heating and drying treatments. Hence, it seems logic to postulate that hazardous diseases can be easily transmitted via nanobacterial contamination of medical and dental equipment. Evaluation of the Hypothesis: It is not enough to claim an agent not living according to the standard view on living creatures, as irrelevant to biological safety of cell cultures, or to human and animal health. Although the nature of prions is still under debate and prions are classified as nonliving, they exist and cause diseases, and thus form a serious risk for animal and human health. The risk was recognized only after enormous economical losses. It appears that nanobacteria situation is rather similar, except the fact that nanobacteria appear to cause or contribute to common hazardous diseases of the mankind. Hence, world-widely well-known organizations such as the Centers for Disease Control and Prevention, the Occupational Safety and Health Administration, and the World Health Organization should pay more attention to transmission of hazardous diseases via nanobacterial contamination of medical and dental equipment.

  2. Tight junctions and human diseases.

    Science.gov (United States)

    Sawada, Norimasa; Murata, Masaki; Kikuchi, Keisuke; Osanai, Makoto; Tobioka, Hirotoshi; Kojima, Takashi; Chiba, Hideki

    2003-09-01

    Tight junctions are intercellular junctions adjacent to the apical end of the lateral membrane surface. They have two functions, the barrier (or gate) function and the fence function. The barrier function of tight junctions regulates the passage of ions, water, and various macromolecules, even of cancer cells, through paracellular spaces. The barrier function is thus relevant to edema, jaundice, diarrhea, and blood-borne metastasis. On the other hand, the fence function maintains cell polarity. In other words, tight junctions work as a fence to prevent intermixing of molecules in the apical membrane with those in the lateral membrane. This function is deeply involved in cancer cell biology, in terms of loss of cell polarity. Of the proteins comprising tight junctions, integral membrane proteins occludin, claudins, and JAMs have been recently discovered. Of these molecules, claudins are exclusively responsible for the formation of tight-junction strands and are connected with the actin cytoskeleton mediated by ZO-1. Thus, both functions of tight junctions are dependent on the integrity of the actin cytoskeleton as well as ATP. Mutations in the claudin14 and the claudin16 genes result in hereditary deafness and hereditary hypomagnesemia, respectively. Some pathogenic bacteria and viruses target and affect the tight-junction function, leading to diseases. In this review, the relationship between tight junctions and human diseases is summarized.

  3. Prioritization of Companion Animal Transmissible Diseases for Policy Intervention in Europe

    DEFF Research Database (Denmark)

    Cito, F.; Rijks, J.; Rantsios, A.T.

    2016-01-01

    A number of papers have been published on the prioritization of transmissible diseases in farm animals and wildlife, based either on semiquantitative or truly quantitative methods, but there is no published literature on the prioritization of transmissible diseases in companion animals. In this s...... reptiles. The methodology presented in this paper can be used to generate accurate priority lists according to narrower and more specific objectives....

  4. Wildlife disease prevalence in human-modified landscapes.

    Science.gov (United States)

    Brearley, Grant; Rhodes, Jonathan; Bradley, Adrian; Baxter, Greg; Seabrook, Leonie; Lunney, Daniel; Liu, Yan; McAlpine, Clive

    2013-05-01

    Human-induced landscape change associated with habitat loss and fragmentation places wildlife populations at risk. One issue in these landscapes is a change in the prevalence of disease which may result in increased mortality and reduced fecundity. Our understanding of the influence of habitat loss and fragmentation on the prevalence of wildlife diseases is still in its infancy. What is evident is that changes in disease prevalence as a result of human-induced landscape modification are highly variable. The importance of infectious diseases for the conservation of wildlife will increase as the amount and quality of suitable habitat decreases due to human land-use pressures. We review the experimental and observational literature of the influence of human-induced landscape change on wildlife disease prevalence, and discuss disease transmission types and host responses as mechanisms that are likely to determine the extent of change in disease prevalence. It is likely that transmission dynamics will be the key process in determining a pathogen's impact on a host population, while the host response may ultimately determine the extent of disease prevalence. Finally, we conceptualize mechanisms and identify future research directions to increase our understanding of the relationship between human-modified landscapes and wildlife disease prevalence. This review highlights that there are rarely consistent relationships between wildlife diseases and human-modified landscapes. In addition, variation is evident between transmission types and landscape types, with the greatest positive influence on disease prevalence being in urban landscapes and directly transmitted disease systems. While we have a limited understanding of the potential influence of habitat loss and fragmentation on wildlife disease, there are a number of important areas to address in future research, particularly to account for the variability in increased and decreased disease prevalence. Previous studies

  5. Age-related changes in the transmission properties of the human lens and their relevance to circadian entrainment

    DEFF Research Database (Denmark)

    Kessel, Line; Lundeman, Jesper Holm; Herbst, Kristina

    2010-01-01

    To characterize age-related changes in the transmission of light through noncataractous human lenses.......To characterize age-related changes in the transmission of light through noncataractous human lenses....

  6. The behaviour of Homo sapiens, the forgotten factor in the transmission of tropical disease.

    Science.gov (United States)

    Gillett, J D

    1985-01-01

    The behaviour of the pathogens responsible for tropical disease and the behaviour of the hosts other than man are both studied in great detail, but the behaviour of man, the third component in these cycles of transmission, is for the most part totally and inexplicably disregarded. Even when the pathogens are actively brought to us through the agency of an arthropod host, we too often ease the passage of the vectors either by unthinkingly providing facilities for their breeding or by neglecting the simple steps that can be taken to prevent their feeding on us. The problem resolves itself into two parts, (i) the collection and collation of relevant data on human behaviour, and (ii) the taking of steps to change this behaviour. Part two has recently been greatly facilitated by the development of radio transmission via artificial satellite. While WHO is now making a start on both these aspects it is doing so at a relatively low level. Instead, the two phases of this new approach should be given top priority even if it means large scale reorganization of relevant university departments and even of WHO itself. We have, after all, had almost 100 years to try out the old methods and, as far as the Third World is concerned, they have for the most part failed.

  7. Transmission of human African trypanosomiasis in the Komo ...

    African Journals Online (AJOL)

    In order to update transmission features of sleeping sickness in that focus, we have conducted epidemiological and entomological surveys in March-April 2008. Methods: Epidemiological investigation relied on a casecontrol study using a quantitative and qualitative methodology (a structured questionnaire). Cases were ...

  8. A history of chagas disease transmission, control, and re-emergence in peri-rural La Joya, Peru.

    Science.gov (United States)

    Delgado, Stephen; Castillo Neyra, Ricardo; Quispe Machaca, Víctor R; Ancca Juárez, Jenny; Chou Chu, Lily; Verastegui, Manuela Renee; Moscoso Apaza, Giovanna M; Bocángel, César D; Tustin, Aaron W; Sterling, Charles R; Comrie, Andrew C; Náquira, César; Cornejo del Carpio, Juan G; Gilman, Robert H; Bern, Caryn; Levy, Michael Z

    2011-02-22

    The history of Chagas disease control in Peru and many other nations is marked by scattered and poorly documented vector control campaigns. The complexities of human migration and sporadic control campaigns complicate evaluation of the burden of Chagas disease and dynamics of Trypanosoma cruzi transmission. We conducted a cross-sectional serological and entomological study to evaluate temporal and spatial patterns of T. cruzi transmission in a peri-rural region of La Joya, Peru. We use a multivariate catalytic model and Bayesian methods to estimate incidence of infection over time and thereby elucidate the complex history of transmission in the area. Of 1,333 study participants, 101 (7.6%; 95% CI: 6.2-9.0%) were confirmed T. cruzi seropositive. Spatial clustering of parasitic infection was found in vector insects, but not in human cases. Expanded catalytic models suggest that transmission was interrupted in the study area in 1996 (95% credible interval: 1991-2000), with a resultant decline in the average annual incidence of infection from 0.9% (95% credible interval: 0.6-1.3%) to 0.1% (95% credible interval: 0.005-0.3%). Through a search of archival newspaper reports, we uncovered documentation of a 1995 vector control campaign, and thereby independently validated the model estimates. High levels of T. cruzi transmission had been ongoing in peri-rural La Joya prior to interruption of parasite transmission through a little-documented vector control campaign in 1995. Despite the efficacy of the 1995 control campaign, T. cruzi was rapidly reemerging in vector populations in La Joya, emphasizing the need for continuing surveillance and control at the rural-urban interface.

  9. Transmission dynamics of rabies virus in Thailand: Implications for disease control

    Directory of Open Access Journals (Sweden)

    Puanghat Apirom

    2005-06-01

    Full Text Available Abstract Background In Thailand, rabies remains a neglected disease with authorities continuing to rely on human death statistics while ignoring the financial burden resulting from an enormous increase in post-exposure prophylaxis. Past attempts to conduct a mass dog vaccination and sterilization program have been limited to Bangkok city and have not been successful. We have used molecular epidemiology to define geographic localization of rabies virus phylogroups and their pattern of spread in Thailand. Methods We analyzed 239 nucleoprotein gene sequences from animal and human brain samples collected from all over Thailand between 1998 and 2002. We then reconstructed a phylogenetic tree correlating these data with geographical information. Results All sequences formed a monophyletic tree of 2 distinct phylogroups, TH1 and TH2. Three subgroups were identified in the TH1 subgroup and were distributed in the middle region of the country. Eight subgroups of TH2 viruses were identified widely distributed throughout the country overlapping the TH1 territory. There was a correlation between human-dependent transportation routes and the distribution of virus. Conclusion Inter-regional migration paths of the viruses might be correlated with translocation of dogs associated with humans. Interconnecting factors between human socioeconomic and population density might determine the transmission dynamics of virus in a rural-to-urban polarity. The presence of 2 or more rabies virus groups in a location might be indicative of a gene flow, reflecting a translocation of dogs within such region and adjacent areas. Different approaches may be required for rabies control based on the homo- or heterogeneity of the virus. Areas containing homogeneous virus populations should be targeted first. Control of dog movement associated with humans is essential.

  10. MUC1 in human milk blocks transmission of human immunodeficiency virus from dendritic cells to T cells

    NARCIS (Netherlands)

    Saeland, E.; Jong, de M.A.W.P.; Nabatov, A.; Kalay, H.; Kooijk, van Y.; Geijtenbeek, T.B.H.

    2009-01-01

    Mother-to-child transmission of human immunodeficiency virus-1 (HIV-1) occurs frequently via breast-feeding. HIV-1 targets DC-SIGN+ dendritic cells (DCs) in mucosal areas that allow efficient transmission of the virus to T cells. Here, we demonstrate that the epithelial mucin MUC1, abundant in milk,

  11. Attributing Climate Conditions for Stable Malaria Transmission to Human Activity in sub-Saharan Africa

    Science.gov (United States)

    Sheldrake, L.; Mitchell, D.; Allen, M. R.

    2015-12-01

    Temperature and precipitation limit areas of stable malaria transmission, but the effects of climate change on the disease remain controversial. Previously, studies have not separated the influence of anthropogenic climate change and natural variability, despite being an essential step in the attribution of climate change impacts. Ensembles of 2900 simulations of regional climate in sub-Saharan Africa for the year 2013, one representing realistic conditions and the other how climate might have been in the absence of human influence, were used to force a P.falciparium climate suitability model developed by the Mapping Malaria Risk in Africa project. Strongest signals were detected in areas of unstable transmission, indicating their heightened sensitivity to climatic factors. Evidently, impacts of human-induced climate change were unevenly distributed: the probability of conditions being suitable for stable malaria transmission were substantially reduced (increased) in the Sahel (Greater Horn of Africa (GHOA), particularly in the Ethiopian and Kenyan highlands). The length of the transmission season was correspondingly shortened in the Sahel and extended in the GHOA, by 1 to 2 months, including in Kericho (Kenya), where the role of climate change in driving recent malaria occurrence is hotly contested. Human-induced warming was primarily responsible for positive anomalies in the GHOA, while reduced rainfall caused negative anomalies in the Sahel. The latter was associated with anthropogenic impacts on the West African Monsoon, but uncertainty in the RCM's ability to reproduce precipitation trends in the region weakens confidence in the result. That said, outputs correspond well with broad-scale changes in observed endemicity, implying a potentially important contribution of anthropogenic climate change to the malaria burden during the past century. Results support the health-framing of climate risk and help indicate hotspots of climate vulnerability, providing

  12. Microsporidian species known to infect humans are present in aquatic birds: implications for transmission via water?

    Science.gov (United States)

    Slodkowicz-Kowalska, Anna; Graczyk, Thaddeus K; Tamang, Leena; Jedrzejewski, Szymon; Nowosad, Andrzej; Zduniak, Piotr; Solarczyk, Piotr; Girouard, Autumn S; Majewska, Anna C

    2006-07-01

    Human microsporidiosis, a serious disease of immunocompetent and immunosuppressed people, can be due to zoonotic and environmental transmission of microsporidian spores. A survey utilizing conventional and molecular techniques for examining feces from 570 free-ranging, captive, and livestock birds demonstrated that 21 animals shed microsporidian spores of species known to infect humans, including Encephalitozoon hellem (20 birds; 3.5%) and Encephalitozoon intestinalis (1 bird; 0.2%). Of 11 avian species that shed E. hellem and E. intestinalis, 8 were aquatic birds (i.e., common waterfowl). The prevalence of microsporidian infections in waterfowl (8.6%) was significantly higher than the prevalence of microsporidian infections in other birds (1.1%) (P < 0.03); waterfowl fecal droppings contained significantly more spores (mean, 3.6 x 10(5) spores/g) than nonaquatic bird droppings contained (mean, 4.4 x 10(4) spores/g) (P < 0.003); and the presence of microsporidian spores of species known to infect humans in fecal samples was statistically associated with the aquatic status of the avian host (P < 0.001). We demonstrated that a single visit of a waterfowl flock can introduce into the surface water approximately 9.1 x 10(8) microsporidian spores of species known to infect humans. Our findings demonstrate that waterborne microsporidian spores of species that infect people can originate from common waterfowl, which usually occur in large numbers and have unlimited access to surface waters, including waters used for production of drinking water.

  13. [Bartonellosis. II. Other Bartonella responsible for human diseases].

    Science.gov (United States)

    Piémont, Y; Heller, R

    1999-01-01

    In addition to Bartonella henselae, five other Bartonella species were involved in human pathology. As for B. henselae, ectoparasites seem to be responsible for the transmission of most or all these bacterial species. B. bacilliformis is responsible for Carrion's disease that occurs in some valleys of Colombia, Ecuador and Peru. This disease is transmitted by biting of infected sandflies. The bacterial reservoir is constituted by humans only. That disease occurs either as an acute form with severe infectious hemolytic anemia (or Oroya fever), or as benign cutaneous tumors, also called verruga peruana. Healthy blood carriers of the bacterium exist. Trench fever was described during the First World War. This non-lethal disease is constituted of recurrent febrile attacks associated particularly with osseous pains. The causative agent of the disease is B. quintana, transmitted by the body louse. Humans seem to be the reservoir of that bacterium. In some patients, B. quintana can be responsible for endocarditis, bacillary angiomatosis and chronic or recurrent bacteremia. Other human infections due to Bartonella sp. have been described: B. vinsonii, isolated from blood of small rodents, and B. elizabethae, the reservoir of which is currently unknown, can be responsible for endocardites. B. clarridgeiae (isolated from blood of 5% of pet cats and 17% of stray cats) may be responsible for human cat scratch disease. All these bartonelloses are diagnosed by non-standard blood culture or by in vitro DNA amplification or by serological testing. Their treatment requires tetracyclines or chloramphenicol or macrolides.

  14. Transmission of human respiratory syncytial virus in the immunocompromised ferret model

    NARCIS (Netherlands)

    de Waal, L. (Leon); S.L. Smits (Saskia); E.J.B. Veldhuis Kroeze (Edwin); G. van Amerongen (Geert); Pohl, M.O. (Marie O.); Osterhaus, A.D.M.E. (Albert D. M. E.); K.J. Stittelaar (Koert)

    2018-01-01

    textabstractHuman respiratory syncytial virus (HRSV) causes substantial morbidity and mortality in vulnerable patients, such as the very young, the elderly, and immunocompromised individuals of any age. Nosocomial transmission of HRSV remains a serious challenge in hospital settings, with

  15. Behaviors, movements, and transmission of droplet-mediated respiratory diseases during transcontinental airline flights

    Science.gov (United States)

    Weiss, Howard; Elon, Lisa; Si, Wenpei; Norris, Sharon L.

    2018-01-01

    With over 3 billion airline passengers annually, the inflight transmission of infectious diseases is an important global health concern. Over a dozen cases of inflight transmission of serious infections have been documented, and air travel can serve as a conduit for the rapid spread of newly emerging infections and pandemics. Despite sensational media stories and anecdotes, the risks of transmission of respiratory viruses in an airplane cabin are unknown. Movements of passengers and crew may facilitate disease transmission. On 10 transcontinental US flights, we chronicled behaviors and movements of individuals in the economy cabin on single-aisle aircraft. We simulated transmission during flight based on these data. Our results indicate there is low probability of direct transmission to passengers not seated in close proximity to an infectious passenger. This data-driven, dynamic network transmission model of droplet-mediated respiratory disease is unique. To measure the true pathogen burden, our team collected 229 environmental samples during the flights. Although eight flights were during Influenza season, all qPCR assays for 18 common respiratory viruses were negative. PMID:29555754

  16. Behaviors, movements, and transmission of droplet-mediated respiratory diseases during transcontinental airline flights.

    Science.gov (United States)

    Hertzberg, Vicki Stover; Weiss, Howard; Elon, Lisa; Si, Wenpei; Norris, Sharon L

    2018-04-03

    With over 3 billion airline passengers annually, the inflight transmission of infectious diseases is an important global health concern. Over a dozen cases of inflight transmission of serious infections have been documented, and air travel can serve as a conduit for the rapid spread of newly emerging infections and pandemics. Despite sensational media stories and anecdotes, the risks of transmission of respiratory viruses in an airplane cabin are unknown. Movements of passengers and crew may facilitate disease transmission. On 10 transcontinental US flights, we chronicled behaviors and movements of individuals in the economy cabin on single-aisle aircraft. We simulated transmission during flight based on these data. Our results indicate there is low probability of direct transmission to passengers not seated in close proximity to an infectious passenger. This data-driven, dynamic network transmission model of droplet-mediated respiratory disease is unique. To measure the true pathogen burden, our team collected 229 environmental samples during the flights. Although eight flights were during Influenza season, all qPCR assays for 18 common respiratory viruses were negative. Copyright © 2018 the Author(s). Published by PNAS.

  17. Molecular Infectious Disease Epidemiology: Survival Analysis and Algorithms Linking Phylogenies to Transmission Trees

    Science.gov (United States)

    Kenah, Eben; Britton, Tom; Halloran, M. Elizabeth; Longini, Ira M.

    2016-01-01

    Recent work has attempted to use whole-genome sequence data from pathogens to reconstruct the transmission trees linking infectors and infectees in outbreaks. However, transmission trees from one outbreak do not generalize to future outbreaks. Reconstruction of transmission trees is most useful to public health if it leads to generalizable scientific insights about disease transmission. In a survival analysis framework, estimation of transmission parameters is based on sums or averages over the possible transmission trees. A phylogeny can increase the precision of these estimates by providing partial information about who infected whom. The leaves of the phylogeny represent sampled pathogens, which have known hosts. The interior nodes represent common ancestors of sampled pathogens, which have unknown hosts. Starting from assumptions about disease biology and epidemiologic study design, we prove that there is a one-to-one correspondence between the possible assignments of interior node hosts and the transmission trees simultaneously consistent with the phylogeny and the epidemiologic data on person, place, and time. We develop algorithms to enumerate these transmission trees and show these can be used to calculate likelihoods that incorporate both epidemiologic data and a phylogeny. A simulation study confirms that this leads to more efficient estimates of hazard ratios for infectiousness and baseline hazards of infectious contact, and we use these methods to analyze data from a foot-and-mouth disease virus outbreak in the United Kingdom in 2001. These results demonstrate the importance of data on individuals who escape infection, which is often overlooked. The combination of survival analysis and algorithms linking phylogenies to transmission trees is a rigorous but flexible statistical foundation for molecular infectious disease epidemiology. PMID:27070316

  18. Optimal combinations of control strategies and cost-effective analysis for visceral leishmaniasis disease transmission.

    Directory of Open Access Journals (Sweden)

    Santanu Biswas

    Full Text Available Visceral leishmaniasis (VL is a deadly neglected tropical disease that poses a serious problem in various countries all over the world. Implementation of various intervention strategies fail in controlling the spread of this disease due to issues of parasite drug resistance and resistance of sandfly vectors to insecticide sprays. Due to this, policy makers need to develop novel strategies or resort to a combination of multiple intervention strategies to control the spread of the disease. To address this issue, we propose an extensive SIR-type model for anthroponotic visceral leishmaniasis transmission with seasonal fluctuations modeled in the form of periodic sandfly biting rate. Fitting the model for real data reported in South Sudan, we estimate the model parameters and compare the model predictions with known VL cases. Using optimal control theory, we study the effects of popular control strategies namely, drug-based treatment of symptomatic and PKDL-infected individuals, insecticide treated bednets and spray of insecticides on the dynamics of infected human and vector populations. We propose that the strategies remain ineffective in curbing the disease individually, as opposed to the use of optimal combinations of the mentioned strategies. Testing the model for different optimal combinations while considering periodic seasonal fluctuations, we find that the optimal combination of treatment of individuals and insecticide sprays perform well in controlling the disease for the time period of intervention introduced. Performing a cost-effective analysis we identify that the same strategy also proves to be efficacious and cost-effective. Finally, we suggest that our model would be helpful for policy makers to predict the best intervention strategies for specific time periods and their appropriate implementation for elimination of visceral leishmaniasis.

  19. [Ticks and transmission of some important diseases by ticks].

    Science.gov (United States)

    Gazyağci, Aycan Nuriye; Aydenızöz, Meral

    2010-01-01

    Ticks which are commonly found all around the world are ectoparasites which are obliged to suck blood from vertebrates such as mammals and birds during all of their periods of develeopment. They may cause toxicities and paralyses in the course of blood sucking through saliva injection and the attachment sites may become ports of entry for secondary agents. Healthy animals that are severely infested by ticks can show a decreased yield and anemia. Young and sick animals can even die. Besides this, ticks are both biological and mechanical vectors for viruses, bacteria, rickettsias, spirochaetas, protozoons and helminths. Ten percent of the ticks identified in the world are associated with 200 diseases. In this review the taxonomy and morphology of ticks, some of the important diseases they carry and the diagnosis and treatment of these diseases are mentioned.

  20. Criticality of Parasitic Disease Transmission in a Diffusive Population

    International Nuclear Information System (INIS)

    He Minhua; Zhang Duanming; Yin Yanping; Chen Zhiyuan; Pan Guijun

    2008-01-01

    Through using the methods of finite-size effect and short time dynamic scaling, we study the critical behavior of parasitic disease spreading process in a diffusive population mediated by a static vector environment. Through comprehensive analysis of parasitic disease spreading we find that this model presents a dynamical phase transition from disease-free state to endemic state with a finite population density. We determine the critical population density, above which the system reaches an epidemic spreading stationary state. We also perform a scaling analysis to determine the order parameter and critical relaxation exponents. The results show that the model does not belong to the usual directed percolation universality class and is compatible with the class of directed percolation with diffusive and conserved fields

  1. Possible non-sexual modes of transmission of human papilloma virus.

    Science.gov (United States)

    Sabeena, Sasidharanpillai; Bhat, Parvati; Kamath, Veena; Arunkumar, Govindakarnavar

    2017-03-01

    There is strong evidence to suggest vertical and horizontal modes of transmission of human papilloma virus (HPV), an established etiologic agent of cervical cancer. Infants, children, and adults can acquire both high-risk and low-risk infections by birth or by close contact even though HPV is mainly transmitted sexually. A thorough review of the literature was performed to assess the possible non-sexual modes of transmission of HPV. An electronic search of databases for review articles, cross-sectional studies, cohort studies, and case reports on non-sexual modes of transmission among sexually unexposed women and children was carried out using search terms such as "human papilloma virus, HPV, transmission, horizontal transmission, vertical transmission, and fomites". Articles published between 1983 and 2015 were retrieved. Epidemiological and clinical data support various non-sexual modes of transmission especially at the time of birth and by close contact. Even though the role of fomites in the transmission of HPV is not well established, HPV-DNA positivity has been reported in transvaginal ultrasound probes and colposcopes after routine disinfection. Awareness needs to be spread among the public about alternate modes of transmission. For a proper understanding of the exact natural history of HPV infection acquired via the non-sexual route, long-term prospective studies need to be undertaken. © 2017 Japan Society of Obstetrics and Gynecology.

  2. Dogma disputed: potential endemic heterosexual transmission of human immunodeficiency virus in Australia.

    Science.gov (United States)

    Chapman, S

    1992-06-01

    The concept of tertiary sexual transmission of human immunodeficiency virus (HIV) has been central to government efforts to communicate notions of risk to heterosexuals in Australia. Data on heterosexually transmitted acquired immune deficiency syndrome (AIDS) and HIV for Australia are reviewed with emphasis given to the probability of misclassification bias in the heterosexually acquired and 'other/undetermined' categories. Tertiary cases are almost certainly rare in Australia, with little evidence of any increase in their incidence since the first cases were recorded. Three factors (low probability of exposure, the infectivity of HIV and a comparatively low rate of sexual partner change) make it improbable that Australian heterosexuals with no risk factors will experience endemic HIV infection, with a caveat to this conclusion lying in the potential of Australian sex tourism to Southeast Asia for introducing HIV into the Australian heterosexual population. Four hegemonic factors which have acted to suppress any serious debate of the notion that HIV in Australia is unlikely to become endemic among heterosexuals are discussed: the political 'democratization' of risk inspired by concerns that gay men should not be further vilified as a victim group; the preventive imperative; a reluctance among health educators to question the very foundations of the message they are employed to deliver; and a reluctance to curtail 'Trojan horse' benefits to sexually transmissible disease prevention engendered by HIV education promoting safe sex messages.

  3. Increasing transmission of antibiotic resistance from animals to humans

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Frimodt-Møller, Niels

    2011-01-01

    The importance of the animal reservoir for emergence of antimicrobial resistance in bacteria in humans is difficult to estimate. In this article we give our estimate of the importance and also highlight on which points we have become wiser during recent years. We conclude that it still is the human...... usage of antibiotics which contributes most to resistance observed in humans, but also that the contribution from animals is large and larger than estimated just a few years ago. This indicates the need to implement restriction on antimicrobial usage for both humans and animals....

  4. Increasing transmission of antibiotic resistance from animals to humans

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Frimodt-Møller, Niels

    2011-01-01

    usage of antibiotics which contributes most to resistance observed in humans, but also that the contribution from animals is large and larger than estimated just a few years ago. This indicates the need to implement restriction on antimicrobial usage for both humans and animals.......The importance of the animal reservoir for emergence of antimicrobial resistance in bacteria in humans is difficult to estimate. In this article we give our estimate of the importance and also highlight on which points we have become wiser during recent years. We conclude that it still is the human...

  5. The effect of recruitment rate and other demographic parameters on the transmission of dengue disease

    Science.gov (United States)

    Supriatna, A. K.; Anggriani, N.

    2015-03-01

    One of important factors which always appears in most of dengue transmission mathematical model is the number of new susceptible recruited into the susceptible compartment. In this paper we discuss the effect of different rates of recruitment on the transmission of dengue disease. We choose a dengue transmission model with the most realistic form of recruitment rate and analyze the effect of environmental change to the transmission of dengue based on the selected model. We model the effect of environmental change by considering that it can alter the value of mosquito's carrying capacity and mosquito's death rate. We found that the most prevalent effect of the environmental change to the transmission of dengue is when it can alter the death rate of the mosquitoes.

  6. Interactions between social structure, demography, and transmission determine disease persistence in primates.

    Science.gov (United States)

    Ryan, Sadie J; Jones, James H; Dobson, Andrew P

    2013-01-01

    Catastrophic declines in African great ape populations due to disease outbreaks have been reported in recent years, yet we rarely hear of similar disease impacts for the more solitary Asian great apes, or for smaller primates. We used an age-structured model of different primate social systems to illustrate that interactions between social structure and demography create 'dynamic constraints' on the pathogens that can establish and persist in primate host species with different social systems. We showed that this varies by disease transmission mode. Sexually transmitted infections (STIs) require high rates of transmissibility to persist within a primate population. In particular, for a unimale social system, STIs require extremely high rates of transmissibility for persistence, and remain at extremely low prevalence in small primates, but this is less constrained in longer-lived, larger-bodied primates. In contrast, aerosol transmitted infections (ATIs) spread and persist at high prevalence in medium and large primates with moderate transmissibility;, establishment and persistence in small-bodied primates require higher relative rates of transmissibility. Intragroup contact structure - the social network - creates different constraints for different transmission modes, and our model underscores the importance of intragroup contacts on infection prior to intergroup movement in a structured population. When alpha males dominate sexual encounters, the resulting disease transmission dynamics differ from when social interactions are dominated by mother-infant grooming events, for example. This has important repercussions for pathogen spread across populations. Our framework reveals essential social and demographic characteristics of primates that predispose them to different disease risks that will be important for disease management and conservation planning for protected primate populations.

  7. Comparing bivalent and quadrivalent human papillomavirus vaccines: economic evaluation based on transmission model.

    Science.gov (United States)

    Jit, Mark; Chapman, Ruth; Hughes, Owain; Choi, Yoon Hong

    2011-09-27

    To compare the effect and cost effectiveness of bivalent and quadrivalent human papillomavirus (HPV) vaccination, taking into account differences in licensure indications, protection against non-vaccine type disease, protection against disease related to HPV types 6 and 11, and reported long term immunogenicity. A model of HPV transmission and disease previously used to inform UK vaccination policy, updated with recent evidence and expanded to include scenarios where the two vaccines differ in duration of protection, cross protection, and end points prevented. United Kingdom. Population Males and females aged 12-75 years. Incremental cost effectiveness ratios for both vaccines and additional cost per dose for the quadrivalent vaccine to be equally cost effective as the bivalent vaccine. The bivalent vaccine needs to be cheaper than the quadrivalent vaccine to be equally cost effective, mainly because of its lack of protection against anogenital warts. The price difference per dose ranges from a median of £19 (interquartile range £12-£27) to £35 (£27-£44) across scenarios about vaccine duration, cross protection, and end points prevented (assuming one quality adjusted life year (QALY) is valued at £30,000 and both vaccines can prevent all types of HPV related cancers). The quadrivalent vaccine may have an advantage over the bivalent vaccine in reducing healthcare costs and QALYs lost. The bivalent vaccine may have an advantage in preventing death due to cancer. However, considerable uncertainty remains about the differential benefit of the two vaccines.

  8. Research priorities for Chagas disease, human African trypanosomiasis and leishmaniasis.

    Science.gov (United States)

    2012-01-01

    This report provides a review and analysis of the research landscape for three diseases - Chagas disease, human African trypanosomiasis and leishmaniasis - that disproportionately afflict poor and remote populations with limited access to health services. It represents the work of the disease reference group on Chagas Disease, Human African Trypanosomiasis and Leishmaniasis (DRG3) which was established to identify key research priorities through review of research evidence and input from stakeholders' consultations. The diseases, which are caused by related protozoan parasites, are described in terms of their epidemiology and diseases burden, clinical forms and pathogenesis, HIV coinfection, diagnosis, drugs and drug resistance, vaccines, vector control, and health-care interventions. Priority areas for research are identified based on criteria such as public health relevance, benefit and impact on poor populations and equity, and feasibility. The priorities are found in the areas of diagnostics, drugs, vector control, asymptomatic infection, economic analysis of treatment and vector control methods, and in some specific issues such as surveillance methods or transmission-blocking vaccines for particular diseases. This report will be useful to researchers, policy and decision-makers, funding bodies, implementation organizations, and civil society. This is one of ten disease and thematic reference group reports that have come out of the TDR Think Tank, all of which have contributed to the development of the Global Report for Research on Infectious Diseases of Poverty, available at: www.who.int/tdr/stewardship/global_report/en/index.html.

  9. Vomiting as a Symptom and Transmission Risk in Norovirus Illness: Evidence from Human Challenge Studies.

    Directory of Open Access Journals (Sweden)

    Amy E Kirby

    Full Text Available In the US, noroviruses are estimated to cause 21 million cases annually with economic losses reaching $2 billion. Outbreak investigations frequently implicate vomiting as a major transmission risk. However, little is known about the characteristics of vomiting as a symptom or the amount of virus present in emesis.Emesis samples and symptomology data were obtained from previous norovirus human challenge studies with GI.1 Norwalk virus, GII.2 Snow Mountain virus, and a pilot study with GII.1 Hawaii virus. Viral titers in emesis were determined using strain-specific quantitative RT-PCR. In all four studies, vomiting was common with 40-100% of infected subjects vomiting at least once. However, only 45% of subjects with vomiting also had diarrhea. Most of the emesis samples had detectable virus and the mean viral titers were 8.0 x 105 and 3.9 x 104 genomic equivalent copies (GEC/ml for GI and GII viruses, respectively (p = 0.02. Sample pH was correlated with GII.2 Snow Mountain virus detection.Half of all subjects with symptomatic infection experienced vomiting and the average subject shed 1.7 x 108 GEC in emesis. Unlike shedding through stool, vomiting is more likely to result in significant environmental contamination, leading to transmission through fomites and airborne droplets. This quantitative data will be critical for risk assessment studies to further understand norovirus transmission and develop effective control measures. The correlation between sample pH and virus detection is consistent with a single site of virus replication in the small intestine and stomach contents becoming contaminated by intestinal reflux. Additionally, the frequency of vomiting without concurrent diarrhea suggests that epidemiology studies that enroll subjects based on the presence of diarrhea may be significantly underestimating the true burden of norovirus disease.

  10. Simultaneous inference of phylogenetic and transmission trees in infectious disease outbreaks

    Science.gov (United States)

    2017-01-01

    Whole-genome sequencing of pathogens from host samples becomes more and more routine during infectious disease outbreaks. These data provide information on possible transmission events which can be used for further epidemiologic analyses, such as identification of risk factors for infectivity and transmission. However, the relationship between transmission events and sequence data is obscured by uncertainty arising from four largely unobserved processes: transmission, case observation, within-host pathogen dynamics and mutation. To properly resolve transmission events, these processes need to be taken into account. Recent years have seen much progress in theory and method development, but existing applications make simplifying assumptions that often break up the dependency between the four processes, or are tailored to specific datasets with matching model assumptions and code. To obtain a method with wider applicability, we have developed a novel approach to reconstruct transmission trees with sequence data. Our approach combines elementary models for transmission, case observation, within-host pathogen dynamics, and mutation, under the assumption that the outbreak is over and all cases have been observed. We use Bayesian inference with MCMC for which we have designed novel proposal steps to efficiently traverse the posterior distribution, taking account of all unobserved processes at once. This allows for efficient sampling of transmission trees from the posterior distribution, and robust estimation of consensus transmission trees. We implemented the proposed method in a new R package phybreak. The method performs well in tests of both new and published simulated data. We apply the model to five datasets on densely sampled infectious disease outbreaks, covering a wide range of epidemiological settings. Using only sampling times and sequences as data, our analyses confirmed the original results or improved on them: the more realistic infection times place more

  11. Simultaneous inference of phylogenetic and transmission trees in infectious disease outbreaks.

    Science.gov (United States)

    Klinkenberg, Don; Backer, Jantien A; Didelot, Xavier; Colijn, Caroline; Wallinga, Jacco

    2017-05-01

    Whole-genome sequencing of pathogens from host samples becomes more and more routine during infectious disease outbreaks. These data provide information on possible transmission events which can be used for further epidemiologic analyses, such as identification of risk factors for infectivity and transmission. However, the relationship between transmission events and sequence data is obscured by uncertainty arising from four largely unobserved processes: transmission, case observation, within-host pathogen dynamics and mutation. To properly resolve transmission events, these processes need to be taken into account. Recent years have seen much progress in theory and method development, but existing applications make simplifying assumptions that often break up the dependency between the four processes, or are tailored to specific datasets with matching model assumptions and code. To obtain a method with wider applicability, we have developed a novel approach to reconstruct transmission trees with sequence data. Our approach combines elementary models for transmission, case observation, within-host pathogen dynamics, and mutation, under the assumption that the outbreak is over and all cases have been observed. We use Bayesian inference with MCMC for which we have designed novel proposal steps to efficiently traverse the posterior distribution, taking account of all unobserved processes at once. This allows for efficient sampling of transmission trees from the posterior distribution, and robust estimation of consensus transmission trees. We implemented the proposed method in a new R package phybreak. The method performs well in tests of both new and published simulated data. We apply the model to five datasets on densely sampled infectious disease outbreaks, covering a wide range of epidemiological settings. Using only sampling times and sequences as data, our analyses confirmed the original results or improved on them: the more realistic infection times place more

  12. Simultaneous inference of phylogenetic and transmission trees in infectious disease outbreaks.

    Directory of Open Access Journals (Sweden)

    Don Klinkenberg

    2017-05-01

    Full Text Available Whole-genome sequencing of pathogens from host samples becomes more and more routine during infectious disease outbreaks. These data provide information on possible transmission events which can be used for further epidemiologic analyses, such as identification of risk factors for infectivity and transmission. However, the relationship between transmission events and sequence data is obscured by uncertainty arising from four largely unobserved processes: transmission, case observation, within-host pathogen dynamics and mutation. To properly resolve transmission events, these processes need to be taken into account. Recent years have seen much progress in theory and method development, but existing applications make simplifying assumptions that often break up the dependency between the four processes, or are tailored to specific datasets with matching model assumptions and code. To obtain a method with wider applicability, we have developed a novel approach to reconstruct transmission trees with sequence data. Our approach combines elementary models for transmission, case observation, within-host pathogen dynamics, and mutation, under the assumption that the outbreak is over and all cases have been observed. We use Bayesian inference with MCMC for which we have designed novel proposal steps to efficiently traverse the posterior distribution, taking account of all unobserved processes at once. This allows for efficient sampling of transmission trees from the posterior distribution, and robust estimation of consensus transmission trees. We implemented the proposed method in a new R package phybreak. The method performs well in tests of both new and published simulated data. We apply the model to five datasets on densely sampled infectious disease outbreaks, covering a wide range of epidemiological settings. Using only sampling times and sequences as data, our analyses confirmed the original results or improved on them: the more realistic infection

  13. Lyapunov functions for a dengue disease transmission model

    International Nuclear Information System (INIS)

    Tewa, Jean Jules; Dimi, Jean Luc; Bowong, Samuel

    2009-01-01

    In this paper, we study a model for the dynamics of dengue fever when only one type of virus is present. For this model, Lyapunov functions are used to show that when the basic reproduction ratio is less than or equal to one, the disease-free equilibrium is globally asymptotically stable, and when it is greater than one there is an endemic equilibrium which is also globally asymptotically stable.

  14. Lyapunov functions for a dengue disease transmission model

    Energy Technology Data Exchange (ETDEWEB)

    Tewa, Jean Jules [Department of Mathematics, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde (Cameroon)], E-mail: tewa@univ-metz.fr; Dimi, Jean Luc [Department of Mathematics, Faculty of Science, University Marien Ngouabi, P.O. Box 69, Brazzaville (Congo, The Democratic Republic of the)], E-mail: jldimi@yahoo.fr; Bowong, Samuel [Department of Mathematics and Computer Science, Faculty of Science, University of Douala, P.O. Box 24157, Douala (Cameroon)], E-mail: samuelbowong@yahoo.fr

    2009-01-30

    In this paper, we study a model for the dynamics of dengue fever when only one type of virus is present. For this model, Lyapunov functions are used to show that when the basic reproduction ratio is less than or equal to one, the disease-free equilibrium is globally asymptotically stable, and when it is greater than one there is an endemic equilibrium which is also globally asymptotically stable.

  15. Transmission Bottleneck Size Estimation from Pathogen Deep-Sequencing Data, with an Application to Human Influenza A Virus.

    Science.gov (United States)

    Sobel Leonard, Ashley; Weissman, Daniel B; Greenbaum, Benjamin; Ghedin, Elodie; Koelle, Katia

    2017-07-15

    The bottleneck governing infectious disease transmission describes the size of the pathogen population transferred from the donor to the recipient host. Accurate quantification of the bottleneck size is particularly important for rapidly evolving pathogens such as influenza virus, as narrow bottlenecks reduce the amount of transferred viral genetic diversity and, thus, may decrease the rate of viral adaptation. Previous studies have estimated bottleneck sizes governing viral transmission by using statistical analyses of variants identified in pathogen sequencing data. These analyses, however, did not account for variant calling thresholds and stochastic viral replication dynamics within recipient hosts. Because these factors can skew bottleneck size estimates, we introduce a new method for inferring bottleneck sizes that accounts for these factors. Through the use of a simulated data set, we first show that our method, based on beta-binomial sampling, accurately recovers transmission bottleneck sizes, whereas other methods fail to do so. We then apply our method to a data set of influenza A virus (IAV) infections for which viral deep-sequencing data from transmission pairs are available. We find that the IAV transmission bottleneck size estimates in this study are highly variable across transmission pairs, while the mean bottleneck size of 196 virions is consistent with a previous estimate for this data set. Furthermore, regression analysis shows a positive association between estimated bottleneck size and donor infection severity, as measured by temperature. These results support findings from experimental transmission studies showing that bottleneck sizes across transmission events can be variable and influenced in part by epidemiological factors. IMPORTANCE The transmission bottleneck size describes the size of the pathogen population transferred from the donor to the recipient host and may affect the rate of pathogen adaptation within host populations. Recent

  16. Dynamical behavior of an epidemic model for a vector-borne disease with direct transmission

    International Nuclear Information System (INIS)

    Cai Liming; Li Xuezhi; Li Zhaoqiang

    2013-01-01

    An epidemic model of a vector-borne disease with direct transmission is investigated. The reproduction number (R 0 ) of the model is obtained. Rigorous qualitative analysis of the model reveals the presence of the phenomenon of backward bifurcation (where the stable disease-free equilibrium (DFE) coexists with a stable endemic equilibrium when the reproduction number of the disease is less than unity) in the standard incidence model. The phenomenon shows that the classical epidemiological requirement of having the reproduction number less than unity is no longer sufficient, although necessary, for effectively controlling the spread of some vector-borne diseases in a community. The backward bifurcation phenomenon can be removed by substituting the standard incidence with a bilinear mass action incidence. By using Lyapunov function theory and LaSalle invariance principle, it is shown that the unique endemic equilibrium for the model with a mass action incidence is globally stable if the reproduction number R mass is greater than one in feasible region. This suggests that the use of standard incidence in modelling some vector-borne diseases with direct transmission results in the presence of backward bifurcation. Numerical simulations analyze the effect of the direct transmission and the disease-induced death rate on dynamics of the disease transmission, and also verify our analyzed results.

  17. Malaria's Missing Number: Calculating the Human Component of R0 by a Within-Host Mechanistic Model of Plasmodium falciparum Infection and Transmission

    OpenAIRE

    Johnston, Geoffrey L.; Smith, David L.; Fidock, David A.

    2013-01-01

    Human infection by malarial parasites of the genus Plasmodium begins with the bite of an infected Anopheles mosquito. Current estimates place malaria mortality at over 650,000 individuals each year, mostly in African children. Efforts to reduce disease burden can benefit from the development of mathematical models of disease transmission. To date, however, comprehensive modeling of the parameters defining human infectivity to mosquitoes has remained elusive. Here, we describe a mechanistic wi...

  18. Human sporotrichosis beyond the epidemic front reveals classical transmission types in Espírito Santo, Brazil.

    Science.gov (United States)

    de Araujo, Mariceli L; Rodrigues, Anderson M; Fernandes, Geisa F; de Camargo, Zoilo P; de Hoog, G Sybren

    2015-08-01

    Sporotrichosis has emerged as the main subcutaneous mycosis of humans and animals around the world. With particular differences in frequency, the major species includes Sporothrix brasiliensis, S. schenckii, S. globosa and S. luriei. In Brazil, the main aspect of this epidemic is based on the zoonotic transmission through the scratches and bites of diseased cats contaminated with S. brasiliensis. Areas free of feline sporotrichosis are poorly characterised in Brazil. We investigated by molecular tools the epidemiology of human sporotrichosis in the Espírito Santo (ES) state, an area adjacent to Rio de Janeiro where is the epicentre of the long-lasting outbreak of cat-transmitted sporotrichosis. The human cases in the ES state reveal the prevalence of classical transmission types where subjects are mainly infected by accidental traumatic inoculation during manipulation of contaminated plant material. In agreement with an environmental source, Sporothrix schenckii was the major aetiological agent in the classical transmission. Unlike Rio de Janeiro, this study shows that cat-transmitted epidemic in Espírito Santo is still scanty, although the geographic proximity and similar climatic features. Sporothrix brasiliensis was the agent in the feline-transmitted cases. Sporothrix globosa was isolated from a patient with fixed cutaneous lesions that did not report any contact with diseased animals. In conclusion, beyond the borders of Rio de Janeiro epidemic, agents of sporotrichosis in Espírito Santo show a scattered occurrence with high species diversity. © 2015 Blackwell Verlag GmbH.

  19. Constant Transmission Properties of Variant Creutzfeldt-Jakob Disease in 5 Countries

    Science.gov (United States)

    Diack, Abigail B.; Ritchie, Diane; Bishop, Matthew; Pinion, Victoria; Brandel, Jean-Philippe; Haik, Stephane; Tagliavini, Fabrizio; Van Duijn, Cornelia; Belay, Ermias D.; Gambetti, Pierluigi; Schonberger, Lawrence B.; Piccardo, Pedro; Will, Robert G.

    2012-01-01

    Variant Creutzfeldt-Jakob disease (vCJD) has been reported in 12 countries. We hypothesized that a common strain of agent is responsible for all vCJD cases, regardless of geographic origin. To test this hypothesis, we inoculated strain-typing panels of wild-type mice with brain material from human vCJD case-patients from France, the Netherlands, Italy, and the United States. Mice were assessed for clinical disease, neuropathologic changes, and glycoform profile; results were compared with those for 2 reference vCJD cases from the United Kingdom. Transmission to mice occurred from each sample tested, and data were similar between non-UK and UK cases, with the exception of the ranking of mean clinical incubation times of mouse lines. These findings support the hypothesis that a single strain of infectious agent is responsible for all vCJD infections. However, differences in incubation times require further subpassage in mice to establish any true differences in strain properties between cases. PMID:23017202

  20. Vector species richness increases haemorrhagic disease prevalence through functional diversity modulating the duration of seasonal transmission.

    Science.gov (United States)

    Park, Andrew W; Cleveland, Christopher A; Dallas, Tad A; Corn, Joseph L

    2016-06-01

    Although many parasites are transmitted between hosts by a suite of arthropod vectors, the impact of vector biodiversity on parasite transmission is poorly understood. Positive relationships between host infection prevalence and vector species richness (SR) may operate through multiple mechanisms, including (i) increased vector abundance, (ii) a sampling effect in which species of high vectorial capacity are more likely to occur in species-rich communities, and (iii) functional diversity whereby communities comprised species with distinct phenologies may extend the duration of seasonal transmission. Teasing such mechanisms apart is impeded by a lack of appropriate data, yet could highlight a neglected role for functional diversity in parasite transmission. We used statistical modelling of extensive host, vector and microparasite data to test the hypothesis that functional diversity leading to longer seasonal transmission explained variable levels of disease in a wildlife population. We additionally developed a simple transmission model to guide our expectation of how an increased transmission season translates to infection prevalence. Our study demonstrates that vector SR is associated with increased levels of disease reporting, but not via increases in vector abundance or via a sampling effect. Rather, the relationship operates by extending the length of seasonal transmission, in line with theoretical predictions.

  1. Transmission dynamics and economics of rabies control in dogs and humans in an African city.

    Science.gov (United States)

    Zinsstag, J; Dürr, S; Penny, M A; Mindekem, R; Roth, F; Menendez Gonzalez, S; Naissengar, S; Hattendorf, J

    2009-09-01

    Human rabies in developing countries can be prevented through interventions directed at dogs. Potential cost-savings for the public health sector of interventions aimed at animal-host reservoirs should be assessed. Available deterministic models of rabies transmission between dogs were extended to include dog-to-human rabies transmission. Model parameters were fitted to routine weekly rabid-dog and exposed-human cases reported in N'Djaména, the capital of Chad. The estimated transmission rates between dogs (beta(d)) were 0.0807 km2/(dogs x week) and between dogs and humans (beta(dh)) 0.0002 km2/(dogs x week). The effective reproductive ratio (R(e)) at the onset of our observations was estimated at 1.01, indicating low-level endemic stability of rabies transmission. Human rabies incidence depended critically on dog-related transmission parameters. We simulated the effects of mass dog vaccination and the culling of a percentage of the dog population on human rabies incidence. A single parenteral dog rabies-mass vaccination campaign achieving a coverage of least 70% appears to be sufficient to interrupt transmission of rabies to humans for at least 6 years. The cost-effectiveness of mass dog vaccination was compared to postexposure prophylaxis (PEP), which is the current practice in Chad. PEP does not reduce future human exposure. Its cost-effectiveness is estimated at US $46 per disability adjusted life-years averted. Cost-effectiveness for PEP, together with a dog-vaccination campaign, breaks even with cost-effectiveness of PEP alone after almost 5 years. Beyond a time-frame of 7 years, it appears to be more cost-effective to combine parenteral dog-vaccination campaigns with human PEP compared to human PEP alone.

  2. New variant of Creutzfeldt-Jakob (vCJD) disease and other human prion diseases under epidemiological surveillance in Brazil

    OpenAIRE

    Gattás, Vera Lúcia; Lima Neto, Antonio Silva; Dimech, George Santiago; Mancini, Denise; Cantarino, Ligia Maria; Marins, José Ricardo Pio; Luna, Expedito José Albuquerque

    2007-01-01

    Abstract To increase the timeliness of detection of human cases of the new variant of Creutzfeldt-Jakob disease (vCJD) and to reduce the risk of transmission, the Brazilian Ministry of Health has established and standardized rules and control measures. These include the definition of criteria for suspect cases, reporting, monitoring, and control measures for illness prevention and transmission. Guidelines to be used by the team of health care staff were published and distributed to health wor...

  3. Chronic Wasting Disease: Transmission Mechanisms and the Possibility of Harvest Management

    Science.gov (United States)

    Potapov, Alex; Merrill, Evelyn; Pybus, Margo; Lewis, Mark A.

    2016-01-01

    We develop a model of CWD management by nonselective deer harvest, currently the most feasible approach available for managing CWD in wild populations. We use the model to explore the effects of 6 common harvest strategies on disease prevalence and to identify potential optimal harvest policies for reducing disease prevalence without population collapse. The model includes 4 deer categories (juveniles, adult females, younger adult males, older adult males) that may be harvested at different rates, a food-based carrying capacity, which influences juvenile survival but not adult reproduction or survival, and seasonal force of infection terms for each deer category under differing frequency-dependent transmission dynamics resulting from environmental and direct contact mechanisms. Numerical experiments show that the interval of transmission coefficients β where the disease can be controlled is generally narrow and efficiency of a harvest policy to reduce disease prevalence depends crucially on the details of the disease transmission mechanism, in particular on the intensity of disease transmission to juveniles and the potential differences in the behavior of older and younger males that influence contact rates. Optimal harvest policy to minimize disease prevalence for each of the assumed transmission mechanisms is shown to depend on harvest intensity. Across mechanisms, a harvest that focuses on antlered deer, without distinguishing between age classes reduces disease prevalence most consistently, whereas distinguishing between young and older antlered deer produces higher uncertainty in the harvest effects on disease prevalence. Our results show that, despite uncertainties, a modelling approach can determine classes of harvest strategy that are most likely to be effective in combatting CWD. PMID:26963921

  4. Forebyggelse af vertikal transmission af human immundefektvirus i Danmark

    DEFF Research Database (Denmark)

    Rasmussen, Maria Birkvad; Rasmussen, Johannes Boyen; Nielsen, Vibeke Rosenfeldt

    2008-01-01

    during the study period. In 79% of the cases, the woman knew her HIV status at the beginning of her pregnancy. The median CD4 count before delivery was 447 x 10(6)/l, and in 76% of the cases the HIV-RNA was ... breastfed. None of the children were infected during pregnancy, delivery or after birth. During the same period of time, 8 children were diagnosed with HIV in Denmark; they were born to mothers whose HIV infection was not diagnosed during pregnancy or delivery and therefore preventive treatment...... was not initiated. CONCLUSION: As long as preventive treatment strategies are followed, there is no transmission of HIV from mother to child, neither during pregnancy nor during or after birth....

  5. Forebyggelse af vertikal transmission af human immundefektvirus i Danmark

    DEFF Research Database (Denmark)

    Rasmussen, Maria Birkvad; Rasmussen, Johannes Boyen; Nielsen, Vibeke Rosenfeldt

    2008-01-01

    during the study period. In 79% of the cases, the woman knew her HIV status at the beginning of her pregnancy. The median CD4 count before delivery was 447 x 10(6)/l, and in 76% of the cases the HIV-RNA was ... breastfed. None of the children were infected during pregnancy, delivery or after birth. During the same period of time, 8 children were diagnosed with HIV in Denmark; they were born to mothers whose HIV infection was not diagnosed during pregnancy or delivery and therefore preventive treatment...... was not initiated. CONCLUSION: As long as preventive treatment strategies are followed, there is no transmission of HIV from mother to child, neither during pregnancy nor during or after birth. Udgivelsesdato: 2008-Aug-18...

  6. Interface of data transmission for a transcutaneous communication system using the human body as transmission medium.

    Science.gov (United States)

    Okamoto, Eiji; Kato, Yoshikuni; Seino, Kazuyuki; Mitamura, Yoshinori

    2012-03-01

    We have been developing a new transcutaneous communication system (TCS) that uses the human body as an electrical conductive medium. We studied an interface circuit of the TCS in order to optimize the leading data current into the human body effectively. Two types of LC circuits were examined for the interface circuit, one was an LC series-parallel circuit, and the other was a parallel-connected LC circuit. The LC series-parallel circuit connected to the body could be tuned to a resonant frequency, and the frequency was determined by the values of an external inductor and an external capacitor. Permittivity of the body did not influence the electrical resonance. Connection of the LC series-parallel circuit to the body degraded the quality factor Q because of the conductivity of the body. However, the LC parallel-connected circuit when connected to the body did not indicate electrical resonance. The LC series-parallel circuit restricts a direct current and a low-frequency current to flow into the body; thus, it can prevent a patient from getting a shock. According to the above results, an LC series-parallel circuit is an optimum interface circuit between the TCS and the body for leading data current into the body effectively and safely.

  7. Spatio-temporal transmission patterns of black-band disease in a coral community.

    Directory of Open Access Journals (Sweden)

    Assaf Zvuloni

    Full Text Available BACKGROUND: Transmission mechanisms of black-band disease (BBD in coral reefs are poorly understood, although this disease is considered to be one of the most widespread and destructive coral infectious diseases. The major objective of this study was to assess transmission mechanisms of BBD in the field based on the spatio-temporal patterns of the disease. METHODOLOGY/PRINCIPAL FINDINGS: 3,175 susceptible and infected corals were mapped over an area of 10x10 m in Eilat (northern Gulf of Aqaba, Red Sea and the distribution of the disease was examined monthly throughout almost two full disease cycles (June 2006-December 2007. Spatial and spatio-temporal analyses were applied to infer the transmission pattern of the disease and to calculate key epidemiological parameters such as (basic reproduction number. We show that the prevalence of the disease is strongly associated with high water temperature. When water temperatures rise and disease prevalence increases, infected corals exhibit aggregated distributions on small spatial scales of up to 1.9 m. Additionally, newly-infected corals clearly appear in proximity to existing infected corals and in a few cases in direct contact with them. We also present and test a model of water-borne infection, indicating that the likelihood of a susceptible coral becoming infected is defined by its spatial location and by the relative spatial distribution of nearby infected corals found in the site. CONCLUSIONS/SIGNIFICANCE: Our results provide evidence that local transmission, but not necessarily by direct contact, is likely to be an important factor in the spread of the disease over the tested spatial scale. In the absence of potential disease vectors with limited mobility (e.g., snails, fireworms in the studied site, water-borne infection is likely to be a significant transmission mechanism of BBD. Our suggested model of water-borne transmission supports this hypothesis. The spatio-temporal analysis also points

  8. Paper money and coins as potential vectors of transmissible disease.

    Science.gov (United States)

    Angelakis, Emmanouil; Azhar, Esam I; Bibi, Fehmida; Yasir, Muhammad; Al-Ghamdi, Ahmed K; Ashshi, Ahmad M; Elshemi, Adel G; Raoult, Didier

    2014-01-01

    Paper currency and coins may be a public health risk when associated with the simultaneous handling of food and could lead to the spread of nosocomial infections. Banknotes recovered from hospitals may be highly contaminated by Staphylococcus aureus. Salmonella species, Escherichia coli and S. aureus are commonly isolated from banknotes from food outlets. Laboratory simulations revealed that methicillin-resistant S. aureus can easily survive on coins, whereas E. coli, Salmonella species and viruses, including human influenza virus, Norovirus, Rhinovirus, hepatitis A virus, and Rotavirus, can be transmitted through hand contact. Large-scale, 16S rRNA, metagenomic studies and culturomics have the capacity to dramatically expand the known diversity of bacteria and viruses on money and fomites. This review summarizes the latest research on the potential of paper currency and coins to serve as sources of pathogenic agents.

  9. The importance of hemovigilance in the transmission of infectious diseases

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Juliano Martins

    2013-06-01

    Full Text Available Background: Hemovigilance is an organized system of surveillance throughout the transfusion chain intended to evaluate information in order to prevent the appearance or recurrence of adverse reactions related to the use of blood products. Objective: The aims of this study were to assess the late reporting of incidents related to possible seroconversion in respect to age, marital status and ethnical background, annual variations in late reporting, the number of reports opened and closed, seroconversion of donors and transfusions of blood products within the window period. Methods: This retrospective, descriptive study used data on blood donations in the blood bank in Uberaba during the period from 2004 to 2011. Some socio-epidemiological characteristics of the donors and serology test results of donors and recipients were analyzed in respect to the late reporting of incidents related to possible seroconversion. The Chi-square test, odds ratio and a regression model were used for statistical analysis. Results: From 2004 to 2011, the blood bank in Uberaba collected 117,857 blood bags, 284 (0.24% of which were investigated for late reported incidents. The profile of the donors was less than 29 years old, unmarried and non-Whites. Differences in age (p-value < 0.0001, marital status (p-value = 0.0002 and ethnical background (p-value < 0.0001 were found to be statistically significant. There was no statistical difference between men and women (0.24% and 0.23% respectively; p-value = 0.951. The number of late reported incidents increased until 2008 followed by a downward trend until 2011. There were twelve cases of seroconversion in subsequent donations (seven human immunodeficiency virus, four hepatitis B and one hepatitis C with proven human immunodeficiency virus infection after screening of only one recipient. Conclusion: The twelve cases of seroconversion in donors with subsequent infection proven in one recipient underscores the importance of

  10. Esporotricose do gato doméstico (Felis catus: transmissão humana Sporothricosis of the domestic cat (Felis catus: human transmission

    Directory of Open Access Journals (Sweden)

    Silvio Alencar Marques

    1993-08-01

    Full Text Available No presente trabalho relata-se caso de paciente, funcionário de hospital veterinário, infectado através de arranhadura de gato doméstico portador de esporotricose. Inquérito domiciliar junto aos proprietários do animal fonte de infecção, revelou dois outros casos presuntivos de esporotricose humana transmitida por gatos, e confirmou o diagnóstico, por cultivo do Sporotrix schenckii, em 3 gatos domésticos adicionais. A esporotricose felina caracteriza-se por lesões cutâneas ulceradas e tendência à disseminação sistêmica e evolução fatal. A transmissão intra e inter-espécie é facilitada pela exuberância de fungos nas lesões cutâneas de felinos infectados.A case of sporothricosis transmitted by cat to a veterinarian hospital employee is reported. Inquiry at domiciliar area of the cat's owner revelled two other presumable cases of human sporothricosis transmitted by cats, and confirmed the diagnosis (by culture of Sporothrix schenckii of disease in three other domestic cats. Feline sporothricosis is characterized by ulcerative, cutaneous lesions and systemic dissemination, which invariably cause animal's death. The transmission of sporothricosis to other animals and humans is enhanced by the great amount of fungus present in cat's lesions.

  11. Comparison of sound transmission in human ears and coupler loaded by audiometric earphones

    DEFF Research Database (Denmark)

    Ciric, Dejan; Hammershøi, Dorte

    2005-01-01

    in the coupler, but since the "ear canal entrance" is not well-defined for the coupler, the mentioned measurements were done at different depths in the coupler. The sound transmission and coupling were described in terms of the pressure division at the entrance of the ear canal and the transmissions in human......, the differences among earphones as well as between human ears and the coupler affect the results of audiometric measurements inducing uncertainty. The influence of these differences is examined by investigating the sound transmission in both human ears and standardized coupler loaded by different audiometric......The thresholds of hearing are usually determined using audiometric earphones. They are calibrated by means of a standardized acoustical coupler. In order to have determined thresholds independent of the earphone type, the coupler should approximate the average human ear closely. Nevertheless...

  12. Antiretroviral pre-exposure prophylaxis prevents vaginal transmission of HIV-1 in humanized BLT mice.

    Directory of Open Access Journals (Sweden)

    Paul W Denton

    2008-01-01

    Full Text Available Worldwide, vaginal transmission now accounts for more than half of newly acquired HIV-1 infections. Despite the urgency to develop and implement novel approaches capable of preventing HIV transmission, this process has been hindered by the lack of adequate small animal models for preclinical efficacy and safety testing. Given the importance of this route of transmission, we investigated the susceptibility of humanized mice to intravaginal HIV-1 infection.We show that the female reproductive tract of humanized bone marrow-liver-thymus (BLT mice is reconstituted with human CD4+ T and other relevant human cells, rendering these humanized mice susceptible to intravaginal infection by HIV-1. Effects of HIV-1 infection include CD4+ T cell depletion in gut-associated lymphoid tissue (GALT that closely mimics what is observed in HIV-1-infected humans. We also show that pre-exposure prophylaxis with antiretroviral drugs is a highly effective method for preventing vaginal HIV-1 transmission. Whereas 88% (7/8 of BLT mice inoculated vaginally with HIV-1 became infected, none of the animals (0/5 given pre-exposure prophylaxis of emtricitabine (FTC/tenofovir disoproxil fumarate (TDF showed evidence of infection (Chi square = 7.5, df = 1, p = 0.006.The fact that humanized BLT mice are susceptible to intravaginal infection makes this system an excellent candidate for preclinical evaluation of both microbicides and pre-exposure prophylactic regimens. The utility of humanized mice to study intravaginal HIV-1 transmission is particularly highlighted by the demonstration that pre-exposure prophylaxis can prevent intravaginal HIV-1 transmission in the BLT mouse model.

  13. Frequency-Dependent Disease Transmission and the Dynamics of the Silene-Ustilago Host-Pathogen System

    NARCIS (Netherlands)

    Thrall, P.H.; Biere, A.; Uyenoyama, M.K.

    1995-01-01

    Models incorporating density-dependent disease transmission functions generally provide a good fit for airborne and directly transmitted bacterial or viral diseases. However, the transmission dynamics of sexually transmitted and vector-borne diseases are likely to be frequency- rather than density-

  14. Microwave reflection, transmission, and absorption by human brain tissue

    Science.gov (United States)

    Ansari, M. A.; Akhlaghipour, N.; Zarei, M.; Niknam, A. R.

    2018-04-01

    These days, the biological effects of electromagnetic (EM) radiations on the brain, especially in the frequency range of mobile communications, have caught the attention of many scientists. Therefore, in this paper, the propagation of mobile phone electromagnetic waves in the brain tissues is investigated analytically and numerically. The brain is modeled by three layers consisting of skull, grey and white matter. First, we have analytically calculated the microwave reflection, transmission, and absorption coefficients using signal flow graph technique. The effect of microwave frequency and variations in the thickness of layers on the propagation of microwave through brain are studied. Then, the penetration of microwave in the layers is numerically investigated by Monte Carlo method. It is shown that the analytical results are in good agreement with those obtained by Monte Carlo method. Our results indicate the absorbed microwave energy depends on microwave frequency and thickness of brain layers, and the absorption coefficient is optimized at a number of frequencies. These findings can be used for comparing the microwave absorbed energy in a child's and adult's brain.

  15. Vector movement underlies avian malaria at upper elevation in Hawaii: implications for transmission of human malaria.

    Science.gov (United States)

    Freed, Leonard A; Cann, Rebecca L

    2013-11-01

    With climate warming, malaria in humans and birds at upper elevations is an emerging infectious disease because development of the parasite in the mosquito vector and vector life history are both temperature dependent. An enhanced-mosquito-movement model from climate warming predicts increased transmission of malaria at upper elevation sites that are too cool for parasite development in the mosquito vector. We evaluate this model with avian malaria (Plasmodium relictum) at 1,900-m elevation on the Island of Hawaii, with air temperatures too low for sporogony in the vector (Culex quinquefasciatus). On a well-defined site over a 14-year period, 10 of 14 species of native and introduced birds became infected, several epizootics occurred, and the increase in prevalence was driven more by resident species than by mobile species that could have acquired their infections at lower elevations. Greater movement of infectious mosquitoes from lower elevations now permits avian malaria to spread at 1,900 m in Hawaii, in advance of climate warming at that elevation. The increase in malaria at upper elevations due to dispersal of infectious mosquitoes is a real alternative to temperature for the increased incidence of human malaria in tropical highlands.

  16. Weather Regulates Location, Timing, and Intensity of Dengue Virus Transmission between Humans and Mosquitoes

    OpenAIRE

    Campbell, Karen M.; Haldeman, Kristin; Lehnig, Chris; Munayco, Cesar V.; Halsey, Eric S.; Laguna-Torres, V. Alberto; Yagui, Mart?n; Morrison, Amy C.; Lin, Chii-Dean; Scott, Thomas W.

    2015-01-01

    Background Dengue is one of the most aggressively expanding mosquito-transmitted viruses. The human burden approaches 400 million infections annually. Complex transmission dynamics pose challenges for predicting location, timing, and magnitude of risk; thus, models are needed to guide prevention strategies and policy development locally and globally. Weather regulates transmission-potential via its effects on vector dynamics. An important gap in understanding risk and roadblock in model devel...

  17. Mother to offspring transmission of chronic wasting disease in reeves' muntjac deer.

    Directory of Open Access Journals (Sweden)

    Amy V Nalls

    Full Text Available The horizontal transmission of prion diseases has been well characterized in bovine spongiform encephalopathy (BSE, chronic wasting disease (CWD of deer and elk and scrapie of sheep, and has been regarded as the primary mode of transmission. Few studies have monitored the possibility of vertical transmission occurring within an infected mother during pregnancy. To study the potential for and pathway of vertical transmission of CWD in the native cervid species, we used a small cervid model-the polyestrous breeding, indoor maintainable, Reeves' muntjac deer-and determined that the susceptibility and pathogenesis of CWD in these deer reproduce that in native mule and white-tailed deer. Moreover, we demonstrate here that CWD prions are transmitted from doe to fawn. Maternal CWD infection also appears to result in lower percentage of live birth offspring. In addition, evolving evidence from protein misfolding cyclic amplification (PMCA assays on fetal tissues suggest that covert prion infection occurs in utero. Overall, our findings demonstrate that transmission of prions from mother to offspring can occur, and may be underestimated for all prion diseases.

  18. Transmission of clonal chromosomal abnormalities in human hematopoietic stem and progenitor cells surviving radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Kraft, Daniela, E-mail: d.kraft@gsi.de [GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Planckstr. 1, 64291 Darmstadt (Germany); Institute for Transfusion Medicine und Immunohematology, DRK-Blutspendedienst Baden-Wuerttemberg—Hessen, Johann Wolfgang Goethe-University Hospital, Sandhofstrasse 1, 60528 Frankfurt (Germany); Ritter, Sylvia, E-mail: s.ritter@gsi.de [GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Planckstr. 1, 64291 Darmstadt (Germany); Durante, Marco, E-mail: m.durante@gsi.de [GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Planckstr. 1, 64291 Darmstadt (Germany); Institute for Condensed Matter Physics, Physics Department, Technical University Darmstadt, Hochschulstraße 6-8, 64289 Darmstadt (Germany); Seifried, Erhard, E-mail: e.seifried@blutspende.de [Institute for Transfusion Medicine und Immunohematology, DRK-Blutspendedienst Baden-Wuerttemberg—Hessen, Johann Wolfgang Goethe-University Hospital, Sandhofstrasse 1, 60528 Frankfurt (Germany); Fournier, Claudia, E-mail: c.fournier@gsi.de [GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Planckstr. 1, 64291 Darmstadt (Germany); Tonn, Torsten, E-mail: t.tonn@blutspende.de [Institute for Transfusion Medicine und Immunohematology, DRK-Blutspendedienst Baden-Wuerttemberg—Hessen, Johann Wolfgang Goethe-University Hospital, Sandhofstrasse 1, 60528 Frankfurt (Germany); Technische Universität Dresden, Med. Fakultät Carl Gustav Carus, Institute for Transfusion Medicine Dresden, German Red Cross Blood Donation Service North-East, Blasewitzer Straße 68/70, 01307 Dresden (Germany)

    2015-07-15

    Highlights: • Radiation induced formation and transmission of chromosomal aberrations were assessed. • Cytogenetic analysis was performed in human CD34+ HSPC by mFISH. • We report transmission of stable aberrations in irradiated, clonally expanded HSPC. • Unstable aberrations in clonally expanded HSPC occur independently of irradiation. • Carbon ions and X-rays bear a similar risk for propagation of cytogenetic changes. - Abstract: In radiation-induced acute myeloid leukemia (rAML), clonal chromosomal abnormalities are often observed in bone marrow cells of patients, suggesting that their formation is crucial in the development of the disease. Since rAML is considered to originate from hematopoietic stem and progenitor cells (HSPC), we investigated the frequency and spectrum of radiation-induced chromosomal abnormalities in human CD34{sup +} cells. We then measured stable chromosomal abnormalities, a possible biomarker of leukemia risk, in clonally expanded cell populations which were grown for 14 days in a 3D-matrix (CFU-assay). We compared two radiation qualities used in radiotherapy, sparsely ionizing X-rays and densely ionizing carbon ions (29 and 60–85 keV/μm, doses between 0.5 and 4 Gy). Only a negligible number of de novo arising, unstable aberrations (≤0.05 aberrations/cell, 97% breaks) were measured in the descendants of irradiated HSPC. However, stable aberrations were detected in colonies formed by irradiated HSPC. All cells of the affected colonies exhibited one or more identical aberrations, indicating their clonal origin. The majority of the clonal rearrangements (92%) were simple exchanges such as translocations (77%) and pericentric inversions (15%), which are known to contribute to the development of rAML. Carbon ions were more efficient in inducing cell killing (maximum of ∼30–35% apoptotic cells for 2 Gy carbon ions compared to ∼25% for X-rays) and chromosomal aberrations in the first cell-cycle after exposure (∼70% and

  19. Animal models for human genetic diseases

    African Journals Online (AJOL)

    Sharif Sons

    The study of human genetic diseases can be greatly aided by animal models because of their similarity .... and gene targeting in embryonic stem cells) has been a powerful tool in .... endonucleases that are designed to make a doublestrand.

  20. Roentgenosemiotics and diagnosis of human diseases

    International Nuclear Information System (INIS)

    Mikhajlov, A.N.

    1989-01-01

    Modern concepts concerning roentgenologic semiotics, diagnosis of almost all the human diseases as well as the features of roentgenologic examintion of organs and systems are described. Roentgenologic symptoms and syndroms are systematized and standardized by anatomy branches. 48 refs

  1. FIRST REPORT OF ACUTE CHAGAS DISEASE BY VECTOR TRANSMISSION IN RIO DE JANEIRO STATE, BRAZIL

    Directory of Open Access Journals (Sweden)

    Luiz Henrique Conde SANGENIS

    2015-08-01

    Full Text Available SUMMARY Chagas disease (CD is an endemic anthropozoonosis from Latin America of which the main means of transmission is the contact of skin lesions or mucosa with the feces of triatomine bugs infected by Trypanosoma cruzi. In this article, we describe the first acute CD case acquired by vector transmission in the Rio de Janeiro State and confirmed by parasitological, serological and PCR tests. The patient presented acute cardiomyopathy and pericardial effusion without cardiac tamponade. Together with fever and malaise, a 3 cm wide erythematous, non-pruritic, papule compatible with a "chagoma" was found on his left wrist. This case report draws attention to the possible transmission of CD by non-domiciled native vectors in non-endemic areas. Therefore, acute CD should be included in the diagnostic workout of febrile diseases and acute myopericarditis in Rio de Janeiro.

  2. A Novel Human Body Area Network for Brain Diseases Analysis.

    Science.gov (United States)

    Lin, Kai; Xu, Tianlang

    2016-10-01

    Development of wireless sensor and mobile communication technology provide an unprecedented opportunity for realizing smart and interactive healthcare systems. Designing such systems aims to remotely monitor the health and diagnose the diseases for users. In this paper, we design a novel human body area network for brain diseases analysis, which is named BABDA. Considering the brain is one of the most complex organs in the human body, the BABDA system provides four function modules to ensure the high quality of the analysis result, which includes initial data collection, data correction, data transmission and comprehensive data analysis. The performance evaluation conducted in a realistic environment with several criteria shows the availability and practicability of the BABDA system.

  3. Modeling routes of chronic wasting disease transmission: Environmental prion persistence promotes deer population decline and extinction

    Science.gov (United States)

    Almberg, Emily S.; Cross, Paul C.; Johnson, Christopher J.; Heisey, Dennis M.; Richards, Bryan J.

    2011-01-01

    Chronic wasting disease (CWD) is a fatal disease of deer, elk, and moose transmitted through direct, animal-to-animal contact, and indirectly, via environmental contamination. Considerable attention has been paid to modeling direct transmission, but despite the fact that CWD prions can remain infectious in the environment for years, relatively little information exists about the potential effects of indirect transmission on CWD dynamics. In the present study, we use simulation models to demonstrate how indirect transmission and the duration of environmental prion persistence may affect epidemics of CWD and populations of North American deer. Existing data from Colorado, Wyoming, and Wisconsin's CWD epidemics were used to define plausible short-term outcomes and associated parameter spaces. Resulting long-term outcomes range from relatively low disease prevalence and limited host-population decline to host-population collapse and extinction. Our models suggest that disease prevalence and the severity of population decline is driven by the duration that prions remain infectious in the environment. Despite relatively low epidemic growth rates, the basic reproductive number, R0, may be much larger than expected under the direct-transmission paradigm because the infectious period can vastly exceed the host's life span. High prion persistence is expected to lead to an increasing environmental pool of prions during the early phases (i.e. approximately during the first 50 years) of the epidemic. As a consequence, over this period of time, disease dynamics will become more heavily influenced by indirect transmission, which may explain some of the observed regional differences in age and sex-specific disease patterns. This suggests management interventions, such as culling or vaccination, will become increasingly less effective as CWD epidemics progress.

  4. Protein Misfolding and Human Disease

    DEFF Research Database (Denmark)

    Gregersen, Niels; Bross, Peter Gerd; Vang, Søren

    2006-01-01

    phenylketonuria, Parkinson's disease, α-1-antitrypsin deficiency, familial neurohypophyseal diabetes insipidus, and short-chain acyl-CoA dehydrogenase deficiency. Despite the differences, an emerging paradigm suggests that the cellular effects of protein misfolding provide a common framework that may contribute...

  5. Annotating the human genome with Disease Ontology

    Science.gov (United States)

    Osborne, John D; Flatow, Jared; Holko, Michelle; Lin, Simon M; Kibbe, Warren A; Zhu, Lihua (Julie); Danila, Maria I; Feng, Gang; Chisholm, Rex L

    2009-01-01

    Background The human genome has been extensively annotated with Gene Ontology for biological functions, but minimally computationally annotated for diseases. Results We used the Unified Medical Language System (UMLS) MetaMap Transfer tool (MMTx) to discover gene-disease relationships from the GeneRIF database. We utilized a comprehensive subset of UMLS, which is disease-focused and structured as a directed acyclic graph (the Disease Ontology), to filter and interpret results from MMTx. The results were validated against the Homayouni gene collection using recall and precision measurements. We compared our results with the widely used Online Mendelian Inheritance in Man (OMIM) annotations. Conclusion The validation data set suggests a 91% recall rate and 97% precision rate of disease annotation using GeneRIF, in contrast with a 22% recall and 98% precision using OMIM. Our thesaurus-based approach allows for comparisons to be made between disease containing databases and allows for increased accuracy in disease identification through synonym matching. The much higher recall rate of our approach demonstrates that annotating human genome with Disease Ontology and GeneRIF for diseases dramatically increases the coverage of the disease annotation of human genome. PMID:19594883

  6. Amyotrophic Lateral Sclerosis and Organ Donation: Is There Risk of Disease Transmission?

    OpenAIRE

    Holmes, Brandon B.; Diamond, Marc I.

    2012-01-01

    A new protocol suggests that patients with amyotrophic lateral sclerosis (ALS) are a viable source of tissue for organ transplantation. However, multiple lines of evidence suggest that many neurodegenerative diseases, including ALS, might progress due to transcellular propagation of protein aggregation among neurons. Transmission of the disease state from donor to host thus may be possible under the permissive circumstances of graft transplantation. We argue for careful patient selection and ...

  7. A new mutation for Huntington disease following maternal transmission of an intermediate allele

    NARCIS (Netherlands)

    Semaka, Alicia; Kay, Chris; Belfroid, René D. M.; Bijlsma, Emilia K.; Losekoot, Monique; van Langen, Irene M.; van Maarle, Merel C.; Oosterloo, Mayke; Hayden, Michael R.; van Belzen, Martine J.

    2015-01-01

    New mutations for Huntington disease (HD) originate from CAG repeat expansion of intermediate alleles (27-35 CAG). Expansions of such alleles into the pathological range (≥ 36 CAG) have been exclusively observed in paternal transmission. We report the occurrence of a new mutation that defies the

  8. Does biodiversity protect humans against infectious disease? Reply

    Science.gov (United States)

    Wood, Chelsea L.; Lafferty, Kevin D.; DeLeo, Giulio; Young, Hillary S.; Hudson, Peter J.; Kuris, Armand M.

    2016-01-01

    The dilution effect is the sort of idea that everyone wants to be true. If nature protects humans against infectious disease, imagine the implications: nature's value could be tallied in terms of human suffering avoided. This makes a potent argument for conservation, convincing even to those who would otherwise be disinclined to support conservation initiatives. The appeal of the dilution effect has been recognized by others: “the desire to make the case for conservation has led to broad claims regarding the benefits of nature conservation for human health” (Bauch et al. 2015). Randolph and Dobson (2012) were among the first to critique these claims, making the case that promotion of conservation to reduce Lyme disease risk, although well intentioned, was flawed. Along with Randolph and Dobson's critique, there have been several calls for a more nuanced scientific assessment of the relationship between biodiversity and disease transmission (Dunn 2010, Salkeld et al. 2013, Wood and Lafferty 2013, Young et al. 2013). In response, supporters of the dilution effect have instead increased the scope of their generalizations with review papers, press releases, and, like Levi et al. (2015), letters. These responses have been successful; it is not uncommon to read papers that repeat the assertion that biodiversity generally interferes with disease transmission and that conservation will therefore generally benefit human health. Here, we explain how Levi et al. (2015) and other, similar commentaries use selective interpretation and shifting definitions to argue for the generality of the dilution effect hypothesis.

  9. Vaccination of pigs two weeks before infection significantly reduces transmission of foot-and-mouth disease virus

    NARCIS (Netherlands)

    Eble, P.L.; Bouma, A.; Bruin, de M.G.M.; Hemert-Kluitenberg, van F.; Oirschot, van J.T.; Dekker, A.

    2004-01-01

    The objective of this study was to investigate whether and at what time interval could vaccination reduce transmission of foot-and-Mouth disease virus (FMDV) among pigs. Reduction of virus transmission by vaccination was determined experimentally. Transmission of FMDV was studied in three groups of

  10. Molecular epidemiology of human oral Chagas disease outbreaks in Colombia.

    Directory of Open Access Journals (Sweden)

    Juan David Ramírez

    Full Text Available BACKGROUND: Trypanosoma cruzi, the causative agent of Chagas disease, displays significant genetic variability revealed by six Discrete Typing Units (TcI-TcVI. In this pathology, oral transmission represents an emerging epidemiological scenario where different outbreaks associated to food/beverages consumption have been reported in Argentina, Bolivia, Brazil, Ecuador and Venezuela. In Colombia, six human oral outbreaks have been reported corroborating the importance of this transmission route. Molecular epidemiology of oral outbreaks is barely known observing the incrimination of TcI, TcII, TcIV and TcV genotypes. METHODOLOGY AND PRINCIPAL FINDINGS: High-throughput molecular characterization was conducted performing MLMT (Multilocus Microsatellite Typing and mtMLST (mitochondrial Multilocus Sequence Typing strategies on 50 clones from ten isolates. Results allowed observing the occurrence of TcI, TcIV and mixed infection of distinct TcI genotypes. Thus, a majority of specific mitochondrial haplotypes and allelic multilocus genotypes associated to the sylvatic cycle of transmission were detected in the dataset with the foreseen presence of mitochondrial haplotypes and allelic multilocus genotypes associated to the domestic cycle of transmission. CONCLUSIONS: These findings suggest the incrimination of sylvatic genotypes in the oral outbreaks occurred in Colombia. We observed patterns of super-infection and/or co-infection with a tailored association with the severe forms of myocarditis in the acute phase of the disease. The transmission dynamics of this infection route based on molecular epidemiology evidence was unraveled and the clinical and biological implications are discussed.

  11. Physiochemical basis of human degenerative disease.

    Science.gov (United States)

    Zeliger, Harold I; Lipinski, Boguslaw

    2015-03-01

    The onset of human degenerative diseases in humans, including type 2 diabetes, cardiovascular disease, neurological disorders, neurodevelopmental disease and neurodegenerative disease has been shown to be related to exposures to persistent organic pollutants, including polychlorinated biphenyls, chlorinated pesticides, polybrominated diphenyl ethers and others, as well as to polynuclear aromatic hydrocarbons, phthalates, bisphenol-A and other aromatic lipophilic species. The onset of these diseases has also been related to exposures to transition metal ions. A physiochemical mechanism for the onset of degenerative environmental disease dependent upon exposure to a combination of lipophilic aromatic hydrocarbons and transition metal ions is proposed here. The findings reported here also, for the first time, explain why aromatic hydrocarbons exhibit greater toxicity than aliphatic hydrocarbons of equal carbon numbers.

  12. Physiochemical basis of human degenerative disease

    Directory of Open Access Journals (Sweden)

    Zeliger Harold I.

    2015-03-01

    Full Text Available The onset of human degenerative diseases in humans, including type 2 diabetes, cardiovascular disease, neurological disorders, neurodevelopmental disease and neurodegenerative disease has been shown to be related to exposures to persistent organic pollutants, including polychlorinated biphenyls, chlorinated pesticides, polybrominated diphenyl ethers and others, as well as to polynuclear aromatic hydrocarbons, phthalates, bisphenol-A and other aromatic lipophilic species. The onset of these diseases has also been related to exposures to transition metal ions. A physiochemical mechanism for the onset of degenerative environmental disease dependent upon exposure to a combination of lipophilic aromatic hydrocarbons and transition metal ions is proposed here. The findings reported here also, for the first time, explain why aromatic hydrocarbons exhibit greater toxicity than aliphatic hydrocarbons of equal carbon numbers.

  13. The corallivorous invertebrate Drupella aids in transmission of brown band disease on the Great Barrier Reef

    Science.gov (United States)

    Nicolet, K. J.; Hoogenboom, M. O.; Gardiner, N. M.; Pratchett, M. S.; Willis, B. L.

    2013-06-01

    Brown band disease (BrB) is an increasingly prevalent coral disease in the Indo-Pacific, but although the macroscopic signs of BrB have been associated with the ciliate Philaster guamensis, many aspects of its ecology remain unknown, particularly how the disease is transmitted among coral colonies. The aim of this study was to assess biotic factors affecting BrB transmission, explicitly testing whether corallivorous species contribute to disease spread. Several fish species were observed feeding on diseased tissue in the field, but did not influence either the progression or transmission rates of BrB on coral colonies in situ. In aquarium-based experiments, the butterflyfish Chaetodon aureofasciatus neither aided nor hindered the transmission of BrB from infected to uninfected corals. In contrast, the coral-feeding gastropod Drupella sp. was a highly effective vector of BrB, infecting more than 40 % of experimental colonies. This study also demonstrated the importance of injury in facilitating BrB infection, supporting the hypothesis that the BrB pathogen invades compromised coral tissue. In conclusion, disturbances and corallivorous activities that injure live corals are likely to contribute to increased occurrence of BrB provided that feeding scars create entry wounds sufficiently extensive to facilitate infection. These findings increase the understanding of the ecology of BrB, enabling better predictions of the prevalence and severity of this disease, and informing strategies for managing the impact of BrB on coral reefs.

  14. Human diseases associated with defective DNA repair

    International Nuclear Information System (INIS)

    Friedberg, E.C.; Ehmann, U.K.; Williams, J.I.

    1979-01-01

    The observations on xeroderma pigmentosum (XP) cells in culture were the first indications of defective DNA repair in association with human disease. Since then, a wealth of information on DNA repair in XP, and to a lesser extent in other diseases, has accumulated in the literature. Rather than clarifying the understanding of DNA repair mechanisms in normal cells and of defective DNA repair in human disease, the literature suggests an extraordinary complexity of both of the phenomena. In this review a number of discrete human diseases are considered separately. An attempt was made to systematically describe the pertinent clinical features and cellular and biochemical defects in these diseases, with an emphasis on defects in DNA metabolism, particularly DNA repair. Wherever possible observations have been correlated and unifying hypotheses presented concerning the nature of the basic defect(s) in these diseases. Discussions of the following diseases are presented: XP, ataxia telangiectasia; Fanconi's anemia; Hutchinson-Gilford progeria syndrome; Bloom's syndrome, Cockayne's syndrome; Down's syndrome; retinoblastoma; chronic lymphocytic leukemia; and other miscellaneous human diseases with possble DNA repair defects

  15. Nipah Virus Transmission from Bats to Humans Associated with Drinking Traditional Liquor Made from Date Palm Sap, Bangladesh, 2011–2014

    Centers for Disease Control (CDC) Podcasts

    2016-06-30

    Sarah Gregory reads an abridged version of the article, Nipah Virus Transmission from Bats to Humans Associated with Drinking Traditional Liquor Made from Date Palm Sap, Bangladesh, 2011–2014.  Created: 6/30/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 6/30/2016.

  16. Resource Manual for Handling Body Fluids in the School Setting To Prevent Transmission of Human Immunodeficiency Virus and Hepatitis B Virus. Revised Edition.

    Science.gov (United States)

    Maryland State Dept. of Health and Mental Hygiene, Baltimore.

    This Maryland resource manual provides local education agencies with guidelines on how to handle body fluids to prevent the transmission of diseases, especially Human Immunodeficiency Virus (HIV) and Hepatitis B Virus (HBV), in the school setting. The first section summarizes the reasons for development of the manual. The second section summarizes…

  17. Resource Manual for Handling Body Fluids in the School Setting To Prevent the Transmission of Human Immunodeficiency Virus and Hepatitis B Virus.

    Science.gov (United States)

    Maryland State Dept. of Health and Mental Hygiene, Baltimore.

    Guidelines to prevent the transmission of blood-borne diseases, especially those caused by the Human Immunodeficiency Virus (HIV) and the Hepatitis B Virus (HBV), in the school setting are provided in this resource manual for school staff. Sections include information on the reasons for the development of this manual; a summary of the means of HIV…

  18. Global biogeography of human infectious diseases.

    Science.gov (United States)

    Murray, Kris A; Preston, Nicholas; Allen, Toph; Zambrana-Torrelio, Carlos; Hosseini, Parviez R; Daszak, Peter

    2015-10-13

    The distributions of most infectious agents causing disease in humans are poorly resolved or unknown. However, poorly known and unknown agents contribute to the global burden of disease and will underlie many future disease risks. Existing patterns of infectious disease co-occurrence could thus play a critical role in resolving or anticipating current and future disease threats. We analyzed the global occurrence patterns of 187 human infectious diseases across 225 countries and seven epidemiological classes (human-specific, zoonotic, vector-borne, non-vector-borne, bacterial, viral, and parasitic) to show that human infectious diseases exhibit distinct spatial grouping patterns at a global scale. We demonstrate, using outbreaks of Ebola virus as a test case, that this spatial structuring provides an untapped source of prior information that could be used to tighten the focus of a range of health-related research and management activities at early stages or in data-poor settings, including disease surveillance, outbreak responses, or optimizing pathogen discovery. In examining the correlates of these spatial patterns, among a range of geographic, epidemiological, environmental, and social factors, mammalian biodiversity was the strongest predictor of infectious disease co-occurrence overall and for six of the seven disease classes examined, giving rise to a striking congruence between global pathogeographic and "Wallacean" zoogeographic patterns. This clear biogeographic signal suggests that infectious disease assemblages remain fundamentally constrained in their distributions by ecological barriers to dispersal or establishment, despite the homogenizing forces of globalization. Pathogeography thus provides an overarching context in which other factors promoting infectious disease emergence and spread are set.

  19. Melatonin and human mitochondrial diseases

    Directory of Open Access Journals (Sweden)

    Reza Sharafati-Chaleshtori

    2017-01-01

    Full Text Available Mitochondrial dysfunction is one of the main causative factors in a wide variety of complications such as neurodegenerative disorders, ischemia/reperfusion, aging process, and septic shock. Decrease in respiratory complex activity, increase in free radical production, increase in mitochondrial synthase activity, increase in nitric oxide production, and impair in electron transport system and/or mitochondrial permeability are considered as the main factors responsible for mitochondrial dysfunction. Melatonin, the pineal gland hormone, is selectively taken up by mitochondria and acts as a powerful antioxidant, regulating the mitochondrial bioenergetic function. Melatonin increases the permeability of membranes and is the stimulator of antioxidant enzymes including superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase. It also acts as an inhibitor of lipoxygenase. Melatonin can cause resistance to oxidation damage by fixing the microsomal membranes. Melatonin has been shown to retard aging and inhibit neurodegenerative disorders, ischemia/reperfusion, septic shock, diabetes, cancer, and other complications related to oxidative stress. The purpose of the current study, other than introducing melatonin, was to present the recent findings on clinical effects in diseases related to mitochondrial dysfunction including diabetes, cancer, gastrointestinal diseases, and diseases related to brain function.

  20. THE CASE OF TRAUMATIC TRANSMISSION CHILD OF HUMAN IMMUNODEFICIENCY VIRUS

    Directory of Open Access Journals (Sweden)

    Yu. V. Ostankova

    2016-01-01

    Full Text Available Aim.  Analysis of phylogenetic relationships of HIV  isolates obtained from a child 8 years old and HIV-positive parents to search for a possible source of infection.Materials and  methods. The  blood  plasma  samples of 3 patients (father, mother and child HIV from Veliky Novgorod were used.  Presented in a group of patients were directed to conduct epidemiological investigation cases  of HIV-1 infection a child from a dysfunctional family.  In the present study we used  genotyping by direct  sequencing of the  site  of the polymerase gene  (pol length of 1285 nt., The gene  encoding the protease (PR length of 465 nt. and a portion of the reverse transcriptase (RT gene length of 820 nt.Results. The study allowed the  identification of the  HIV virus in clinical  samples. HIV-1 subtype A1 (IDU-A was detected in all cases.  Phylogenetic analysis of isolates, where the  control  samples using   HIV-1  isolates obtained  previously  from Veliky Novgorod, possible to identify grouped in a separate cluster  sample from the mother, father  and  child, which  makes it possible to conclude about  intrafamily HIV infected child  by  one  of his  parents. The  nucleotide identity  of the  samples obtained from the  mother  and  the  child, showed a higher percentage of similarity – 98.4%, compared with  the  identity of the  samples between the  father  and  the mother  and between father and child (96.2% and 94.2%, respectively. Differences natural  polymorphisms in  protease and reverse  transcriptase genes  of the parents and  the child are discussed. Conclusion. The analysis of phylogenetic relationships of HIV isolates showed that the source  of infection of the child 8 years old, born and  living  in socially  disadvantaged families with HIV-positive parents, is his mother. Way parenteral transmission of infection by random simultaneous trauma  in the mother  and child

  1. Plebotomine Vectors of Human Disease.

    Science.gov (United States)

    1984-12-30

    incriminated as vectors of Leishmania mexicana among rodents and/or humans from Mexico to the Amazon Basin. Specimens referable to L. olmeca olmeca...in the format similar to that given for the species group baityi included in this report. Additional phlebotomines from Tanzania, Brazil, Peru and...species group baityi included in this report. Additional phlebotomines from Tanzania, Brazil, Peru and Venezuela were slide-mounted and added to the

  2. Genomic uracil and human disease

    DEFF Research Database (Denmark)

    Hagen, Lars; Pena Diaz, Javier; Kavli, Bodil

    2006-01-01

    Uracil is present in small amounts in DNA due to spontaneous deamination of cytosine and incorporation of dUMP during replication. While deamination generates mutagenic U:G mismatches, incorporated dUMP results in U:A pairs that are not directly mutagenic, but may be cytotoxic. In most cells, mut...... retroviral infections. Ung(-/-) mice have a similar phenotype and develop B-cell lymphomas late in life. However, there is no evidence indicating that UNG deficiency causes lymphomas in humans....

  3. Genesis of mammalian prions: from non-infectious amyloid fibrils to a transmissible prion disease.

    Directory of Open Access Journals (Sweden)

    Natallia Makarava

    2011-12-01

    Full Text Available The transmissible agent of prion disease consists of a prion protein in its abnormal, β-sheet rich state (PrP(Sc, which is capable of replicating itself according to the template-assisted mechanism. This mechanism postulates that the folding pattern of a newly recruited polypeptide chain accurately reproduces that of a PrP(Sc template. Here we report that authentic PrP(Sc and transmissible prion disease can be generated de novo in wild type animals by recombinant PrP (rPrP amyloid fibrils, which are structurally different from PrP(Sc and lack any detectable PrP(Sc particles. When induced by rPrP fibrils, a long silent stage that involved two serial passages preceded development of the clinical disease. Once emerged, the prion disease was characterized by unique clinical, neuropathological, and biochemical features. The long silent stage to the disease was accompanied by significant transformation in neuropathological properties and biochemical features of the proteinase K-resistant PrP material (PrPres before authentic PrP(Sc evolved. The current work illustrates that transmissible prion diseases can be induced by PrP structures different from that of authentic PrP(Sc and suggests that a new mechanism different from the classical templating exists. This new mechanism designated as "deformed templating" postulates that a change in the PrP folding pattern from the one present in rPrP fibrils to an alternative specific for PrP(Sc can occur. The current work provides important new insight into the mechanisms underlying genesis of the transmissible protein states and has numerous implications for understanding the etiology of neurodegenerative diseases.

  4. Methicillin-Resistant Staphylococcus aureus CC398 in Humans and Pigs in Norway: A "One Health" Perspective on Introduction and Transmission.

    Science.gov (United States)

    Grøntvedt, Carl Andreas; Elstrøm, Petter; Stegger, Marc; Skov, Robert Leo; Skytt Andersen, Paal; Larssen, Kjersti Wik; Urdahl, Anne Margrete; Angen, Øystein; Larsen, Jesper; Åmdal, Solfrid; Løtvedt, Siri Margrete; Sunde, Marianne; Bjørnholt, Jørgen Vildershøj

    2016-12-01

     Emerging livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) persist in livestock populations and represent a reservoir for transmission to humans. Understanding the routes of introduction and further transmission is crucial to control this threat to human health.  All reported cases of livestock-associated MRSA (CC398) in humans and pigs in Norway between 2008 and 2014 were included. Data were collected during an extensive outbreak investigation, including contact tracing and stringent surveillance. Whole-genome sequencing of isolates from all human cases and pig farms was performed to support and expand the epidemiological findings. The national strategy furthermore included a "search-and-destroy" policy at the pig farm level.  Three outbreak clusters were identified, including 26 pig farms, 2 slaughterhouses, and 36 humans. Primary introductions likely occurred by human transmission to 3 sow farms with secondary transmission to other pig farms, mainly through animal trade and to a lesser extent via humans or livestock trucks. All MRSA CC398 isolated from humans without an epidemiological link to the outbreaks were genetically distinct from isolates within the outbreak clusters indicating limited dissemination to the general population.  This study identified preventable routes of MRSA CC398 introduction and transmission: human occupational exposure, trade of pigs and livestock transport vehicles. These findings are essential for keeping pig populations MRSA free and, from a "One Health" perspective, preventing pig farms from becoming reservoirs for MRSA transmission to humans. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.

  5. The Prevalence of Different Human Immunodeficiency Virus Transmission Routes and Knowledge about AIDS in Infected People with HIV in Sirjan

    Directory of Open Access Journals (Sweden)

    Mahin Behzadpour

    2012-06-01

    Full Text Available Background & Objective: The immune system of Patients with Acquired Immune Deficiency Syndrome (AIDS is weekend because of Human immunodeficiency virus (HIV infection, and they become vulnerable to several opportunistic and non-opportunistic pathogens and different carcinomas. IV drug abuse, sexual contact, occupational transmission, blood transfusion and maternal-fetal transmission are well known transmission routes for HIV infection. This study was under taken to investigate the prevalence of HIV transmission routs in the HIV infected population of Sirjan, and their knowledge about the disease, in order to plan better preventive strategies. Materials & Methods: A cross sectional study was planned. During a 6-month period in 2010, all of the HIV infected people in Sirjan (old and new cases who had a file at the consultation center for high risk behavior, completed a valid and reliable questionnaire. Results: The definite route of transmission was not clear in any of the patients because they had more than one suspicious route. Injected drug abusers were the most common (88.4% followed by those who got tattoos (79.1%, invasive therapeutic procedures, dentistry, surgery and endoscopy (56.1%, high risk sexual behavior (62.8%, bloodletting (9.3%, injuries in the barbershop (9.3% and blood transfusion (2.3%. Conclusion: All of the HIV infected cases in Sirjan were involved with several high risk behaviors, but the major route of transmission, similar to other parts of the country was injected drug abuse. Educational programs for prevention of AIDS should be followed seriously and special attention should be paid to groups with multiple high risk behaviors.

  6. Turbulent dispersivity under conditions relevant to airborne disease transmission between laboratory animals

    Science.gov (United States)

    Halloran, Siobhan; Ristenpart, William

    2013-11-01

    Virologists and other researchers who test pathogens for airborne disease transmissibility often place a test animal downstream from an inoculated animal and later determine whether the test animal became infected. Despite the crucial role of the airflow in pathogen transmission between the animals, to date the infectious disease community has paid little attention to the effect of airspeed or turbulent intensity on the probability of transmission. Here we present measurements of the turbulent dispersivity under conditions relevant to experimental tests of airborne disease transmissibility between laboratory animals. We used time lapse photography to visualize the downstream transport and turbulent dispersion of smoke particulates released from a point source downstream of an axial fan, thus mimicking the release and transport of expiratory aerosols exhaled by an inoculated animal. We show that for fan-generated turbulence the plume width is invariant with the mean airspeed and, close to the point source, increases linearly with downstream position. Importantly, the turbulent dispersivity is insensitive to the presence of meshes placed downstream from the point source, indicating that the fan length scale dictates the turbulent intensity and corresponding dispersivity.

  7. The ecological foundations of transmission potential and vector-borne disease in urban landscapes.

    Science.gov (United States)

    LaDeau, Shannon L; Allan, Brian F; Leisnham, Paul T; Levy, Michael Z

    2015-07-01

    Urban transmission of arthropod-vectored disease has increased in recent decades. Understanding and managing transmission potential in urban landscapes requires integration of sociological and ecological processes that regulate vector population dynamics, feeding behavior, and vector-pathogen interactions in these unique ecosystems. Vectorial capacity is a key metric for generating predictive understanding about transmission potential in systems with obligate vector transmission. This review evaluates how urban conditions, specifically habitat suitability and local temperature regimes, and the heterogeneity of urban landscapes can influence the biologically-relevant parameters that define vectorial capacity: vector density, survivorship, biting rate, extrinsic incubation period, and vector competence.Urban landscapes represent unique mosaics of habitat. Incidence of vector-borne disease in urban host populations is rarely, if ever, evenly distributed across an urban area. The persistence and quality of vector habitat can vary significantly across socio-economic boundaries to influence vector species composition and abundance, often generating socio-economically distinct gradients of transmission potential across neighborhoods.Urban regions often experience unique temperature regimes, broadly termed urban heat islands (UHI). Arthropod vectors are ectothermic organisms and their growth, survival, and behavior are highly sensitive to environmental temperatures. Vector response to UHI conditions is dependent on regional temperature profiles relative to the vector's thermal performance range. In temperate climates UHI can facilitate increased vector development rates while having countervailing influence on survival and feeding behavior. Understanding how urban heat island (UHI) conditions alter thermal and moisture constraints across the vector life cycle to influence transmission processes is an important direction for both empirical and modeling research.There remain

  8. The landscape configuration of zoonotic transmission of Ebola virus disease in West and Central Africa: interaction between population density and vegetation cover

    Directory of Open Access Journals (Sweden)

    Michael G. Walsh

    2015-01-01

    Full Text Available Ebola virus disease (EVD is an emerging infectious disease of zoonotic origin that has been responsible for high mortality and significant social disruption in West and Central Africa. Zoonotic transmission of EVD requires contact between susceptible human hosts and the reservoir species for Ebolaviruses, which are believed to be fruit bats. Nevertheless, features of the landscape that may facilitate such points of contact have not yet been adequately identified. Nor have spatial dependencies between zoonotic EVD transmission and landscape structures been delineated. This investigation sought to describe the spatial relationship between zoonotic EVD transmission events, or spillovers, and population density and vegetation cover. An inhomogeneous Poisson process model was fitted to all precisely geolocated zoonotic transmissions of EVD in West and Central Africa. Population density was strongly associated with spillover; however, there was significant interaction between population density and green vegetation cover. In areas of very low population density, increasing vegetation cover was associated with a decrease in risk of zoonotic transmission, but as population density increased in a given area, increasing vegetation cover was associated with increased risk of zoonotic transmission. This study showed that the spatial dependencies of Ebolavirus spillover were associated with the distribution of population density and vegetation cover in the landscape, even after controlling for climate and altitude. While this is an observational study, and thus precludes direct causal inference, the findings do highlight areas that may be at risk for zoonotic EVD transmission based on the spatial configuration of important features of the landscape.

  9. Transmission of infectious diseases from internationally adopted children to their adoptive families.

    Science.gov (United States)

    Sciauvaud, J; Rigal, E; Pascal, J; Nourrisson, C; Poirier, P; Poirier, V; Vidal, M; Mrozek, N; Laurichesse, H; Beytout, J; Labbe, A; Lesens, O

    2014-08-01

    Internationally adopted children may suffer from different pathologies, including infectious diseases contracted in the country of origin. We evaluated the frequency of infectious diseases that may disseminate from adoptees to adoptive families on their arrival in France. All children who attended the clinic for international adoption in Clermont-Ferrand from January 2009 through to December 2011 were eligible for inclusion in the study. Standardized medical records dedicated to international adoption were retrospectively reviewed for demographic data, clinical diagnosis, and biological and radiological results. Data were completed by phone interviews with adoptive families after informed consent. One hundred and forty-two medical records were retrospectively reviewed and 86% of families agreed to be interviewed. One hundred and seventy-one potentially transmissible infections were diagnosed in 142 children, 12% (n = 20) of which were transmitted to adoptive families. Most of these infections were benign and transmission was restricted to the close family. Tinea was diagnosed in 44 adoptees and transmitted in 15 cases. Panton Valentine leukocidin producing methicillin-sensitive S. aureus (MSSA) was transmitted to an adoptive father who required hospitalization for bursitis. Transmission also occurred for CMV (n = 1), hepatitis A (n = 1), giardiasis (n = 1), scabies (n = 1), Moluscum (n = 2) and pediculosis (n = 2). Two cases of chronic hepatitis B and latent tuberculosis were diagnosed without subsequent transmission. In conclusion, infectious diseases are common in internationally adopted children and should be detected shortly after arrival to avoid transmission. © 2013 The Authors Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases.

  10. Amyotrophic lateral sclerosis and organ donation: is there risk of disease transmission?

    Science.gov (United States)

    Holmes, Brandon B; Diamond, Marc I

    2012-12-01

    A new protocol suggests that patients with amyotrophic lateral sclerosis (ALS) are a viable source of tissue for organ transplantation. However, multiple lines of evidence suggest that many neurodegenerative diseases, including ALS, might progress due to transcellular propagation of protein aggregation among neurons. Transmission of the disease state from donor to host thus may be possible under the permissive circumstances of graft transplantation. We argue for careful patient selection and close longitudinal follow-up of recipients when harvesting organs from individuals with neurodegenerative disease, especially dominantly inherited forms. Copyright © 2012 American Neurological Association.

  11. Maternal Proviral Load and Vertical Transmission of Human T Cell Lymphotropic Virus Type 1 in Guinea-Bissau

    NARCIS (Netherlands)

    van Tienen, Carla; McConkey, Samuel J.; de Silva, Thushan I.; Cotten, Matthew; Kaye, Steve; Sarge-Njie, Ramu; da Costa, Carlos; Gonçalves, Nato; Parker, Julia; Vincent, Tim; Jaye, Assan; Aaby, Peter; Whittle, Hilton; Schim van der Loeff, Maarten

    2012-01-01

    The relative importance of routes of transmission of human T cell lymphotropic virus type 1 (HTLV-1) in Guinea-Bissau is largely unknown; vertical transmission is thought to be important, but there are very few existing data. We aimed to examine factors associated with transmission in mothers and

  12. Topographic determinants of foot and mouth disease transmission in the UK 2001 epidemic

    Directory of Open Access Journals (Sweden)

    Keeling Matthew J

    2006-01-01

    Full Text Available Abstract Background A key challenge for modelling infectious disease dynamics is to understand the spatial spread of infection in real landscapes. This ideally requires a parallel record of spatial epidemic spread and a detailed map of susceptible host density along with relevant transport links and geographical features. Results Here we analyse the most detailed such data to date arising from the UK 2001 foot and mouth epidemic. We show that Euclidean distance between infectious and susceptible premises is a better predictor of transmission risk than shortest and quickest routes via road, except where major geographical features intervene. Conclusion Thus, a simple spatial transmission kernel based on Euclidean distance suffices in most regions, probably reflecting the multiplicity of transmission routes during the epidemic.

  13. Blocking effects of human tau on squid giant synapse transmission and its prevention by T-817 MA

    Directory of Open Access Journals (Sweden)

    Herman eMoreno

    2011-05-01

    Full Text Available Filamentous tau inclusions are hallmarks of Alzheimer’s disease (AD and related neurodegenerative tauopathies, but the molecular mechanisms involved in tau mediated changes in neuronal function and their possible effects on synaptic transmission are unknown. We have evaluated the effects of human tau protein injected directly into the presynaptic terminal axon of the squid giant synapse, which affords functional, structural, and biochemical analysis of its action on the synaptic release process. Indeed, we have found that at physiological concentrations recombinant human tau isoforms (h-tau 42 become phosphorylated, produce a rapid synaptic transmission block, and induce the formation of clusters of aggregated synaptic vesicles in the vicinity of the active zone. Presynaptic voltage clamp recordings demonstrate that h-tau does not modify the presynaptic calcium current amplitude or kinetics. Analysis of synaptic noise at the post-synaptic axon following pre-synaptic h-tau42 microinjection revealed an initial phase of increase spontaneous transmitter release followed by a marked reduction in noise. Finally, systemic administration of T-817MA, a proposed neuro-protective agent, rescued tau-induced synaptic abnormalities. Our results show novel mechanisms of h-tau42 mediated synaptic transmission failure and more importantly identify a potential therapeutic agent to treat/prevent tau-related neurotoxicity.

  14. Blocking Effects of Human Tau on Squid Giant Synapse Transmission and Its Prevention by T-817 MA

    Science.gov (United States)

    Moreno, Herman; Choi, Soonwook; Yu, Eunah; Brusco, Janaina; Avila, Jesus; Moreira, Jorge E.; Sugimori, Mutsuyuki; Llinás, Rodolfo R.

    2011-01-01

    Filamentous tau inclusions are hallmarks of Alzheimer's disease and related neurodegenerative tauopathies, but the molecular mechanisms involved in tau-mediated changes in neuronal function and their possible effects on synaptic transmission are unknown. We have evaluated the effects of human tau protein injected directly into the presynaptic terminal axon of the squid giant synapse, which affords functional, structural, and biochemical analysis of its action on the synaptic release process. Indeed, we have found that at physiological concentration recombinant human tau (h-tau42) becomes phosphorylated, produces a rapid synaptic transmission block, and induces the formation of clusters of aggregated synaptic vesicles in the vicinity of the active zone. Presynaptic voltage clamp recordings demonstrate that h-tau42 does not modify the presynaptic calcium current amplitude or kinetics. Analysis of synaptic noise at the post-synaptic axon following presynaptic h-tau42 microinjection revealed an initial phase of increase spontaneous transmitter release followed by a marked reduction in noise. Finally, systemic administration of T-817MA, a proposed neuro-protective agent, rescued tau-induced synaptic abnormalities. Our results show novel mechanisms of h-tau42 mediated synaptic transmission failure and identify a potential therapeutic agent to treat tau-related neurotoxicity. PMID:21629767

  15. Prospective Characterization of the Risk Factors for Transmission and Symptoms of Primary Human Herpesvirus Infections Among Ugandan Infants.

    Science.gov (United States)

    Gantt, Soren; Orem, Jackson; Krantz, Elizabeth M; Morrow, Rhoda Ashley; Selke, Stacy; Huang, Meei-Li; Schiffer, Joshua T; Jerome, Keith R; Nakaganda, Annet; Wald, Anna; Casper, Corey; Corey, Lawrence

    2016-07-01

    Human herpesvirus (HHV) infections are common during infancy. Primary infections are frequently asymptomatic and best studied prospectively by using direct viral detection. Oropharyngeal swab specimens were collected weekly from Ugandan newborn infants, their mothers, and other children in the household. Blood specimens were collected every 4 months. Samples were tested for herpes simplex virus (HSV) types 1 and 2, Epstein-Barr virus (EBV), cytomegalovirus (CMV), HHV-6A, HHV-6B, and HHV-8, using quantitative polymerase chain reaction. Thirty-two infants, 32 mothers, and 49 other household children were followed for a median of 57 weeks. Seventeen mothers had human immunodeficiency virus type 1 (HIV) infection; no infants acquired HIV-1. The 12-month incidence of postnatal infection was 76% for HHV-6B, 59% for CMV, 47% for EBV, 8% for HSV-1, and 0% for HHV-8. The quantity of oropharyngeal shedding by contacts was associated with HHV-6A or HHV-6B transmission. Maternal HIV-1 infection was associated with EBV transmission, while breastfeeding and younger child contacts were associated with CMV transmission. Except for HSV-1, primary HHV infections were subclinical. By capturing exposures and acquisition events, we found that the incidence and risk factors of infection vary by HHV type. HSV-1 infection, unlike other HHV infections, caused acute clinical illness in these infants. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  16. Malaria's missing number: calculating the human component of R0 by a within-host mechanistic model of Plasmodium falciparum infection and transmission.

    Directory of Open Access Journals (Sweden)

    Geoffrey L Johnston

    2013-04-01

    Full Text Available Human infection by malarial parasites of the genus Plasmodium begins with the bite of an infected Anopheles mosquito. Current estimates place malaria mortality at over 650,000 individuals each year, mostly in African children. Efforts to reduce disease burden can benefit from the development of mathematical models of disease transmission. To date, however, comprehensive modeling of the parameters defining human infectivity to mosquitoes has remained elusive. Here, we describe a mechanistic within-host model of Plasmodium falciparum infection in humans and pathogen transmission to the mosquito vector. Our model incorporates the entire parasite lifecycle, including the intra-erythrocytic asexual forms responsible for disease, the onset of symptoms, the development and maturation of intra-erythrocytic gametocytes that are transmissible to Anopheles mosquitoes, and human-to-mosquito infectivity. These model components were parameterized from malaria therapy data and other studies to simulate individual infections, and the ensemble of outputs was found to reproduce the full range of patient responses to infection. Using this model, we assessed human infectivity over the course of untreated infections and examined the effects in relation to transmission intensity, expressed by the basic reproduction number R0 (defined as the number of secondary cases produced by a single typical infection in a completely susceptible population. Our studies predict that net human-to-mosquito infectivity from a single non-immune individual is on average equal to 32 fully infectious days. This estimate of mean infectivity is equivalent to calculating the human component of malarial R0 . We also predict that mean daily infectivity exceeds five percent for approximately 138 days. The mechanistic framework described herein, made available as stand-alone software, will enable investigators to conduct detailed studies into theories of malaria control, including the effects of

  17. Characteristics of cyprinid herpesvirus 3 in different phases of infection: implications for disease transmission and control.

    Science.gov (United States)

    Sunarto, Agus; McColl, Kenneth A; Crane, Mark St J; Schat, Karel A; Slobedman, Barry; Barnes, Andrew C; Walker, Peter J

    2014-08-08

    Koi herpesvirus disease (KHVD) is an emerging and highly contagious viral disease of koi and common carp (Cyprinus carpio), causing mass mortalities and huge economic losses to the carp aquaculture industry. The disease has spread rapidly to 28 countries worldwide. However, mechanisms of koi herpesvirus (species Cyprinid herpesvirus 3; CyHV-3) transmission remain unclear. A potential experimental model of CyHV-3 infection in carp was used to characterise CyHV-3 in different phases of infection and to demonstrate that CyHV-3 persists in survivor fish and has the capacity to reactivate and transmit the disease to healthy fish. During acute infection, which occurred when fish were maintained at 22°C, viral genes were abundantly expressed and infectious virus was produced in association with tissue damage, clinical disease and mortality. In fish maintained at a lower temperature (11°C), viral DNA was present but viral gene expression was absent or greatly restricted, infectious virus was not recovered and there was no evidence of disease. Productive replication was re-initiated following an increase in water temperature to 22°C, resulting in 45% mortality. Shedding of reactivated virus killed 75% of cohabitating naïve fish, suggesting a potential risk for disease transmission. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  18. History Classroom Interactions and the Transmission of the Recent Memory of Human Rights Violations in Chile

    Science.gov (United States)

    Oteíza, Teresa; Henríquez, Rodrigo; Pinuer, Claudio

    2015-01-01

    The purpose of this article is to examine history classroom interactions in Chilean secondary schools in relation to the transmission of historical memories of human rights violations committed by Augusto Pinochet's dictatorship from 1973 to 1990. Corpora of this research are comprised of history lessons filmed in the two types of public schools…

  19. Tracking Dengue Virus Intra-host Genetic Diversity during Human-to-Mosquito Transmission.

    Directory of Open Access Journals (Sweden)

    Shuzhen Sim

    Full Text Available Dengue virus (DENV infection of an individual human or mosquito host produces a dynamic population of closely-related sequences. This intra-host genetic diversity is thought to offer an advantage for arboviruses to adapt as they cycle between two very different host species, but it remains poorly characterized. To track changes in viral intra-host genetic diversity during horizontal transmission, we infected Aedes aegypti mosquitoes by allowing them to feed on DENV2-infected patients. We then performed whole-genome deep-sequencing of human- and matched mosquito-derived DENV samples on the Illumina platform and used a sensitive variant-caller to detect single nucleotide variants (SNVs within each sample. >90% of SNVs were lost upon transition from human to mosquito, as well as from mosquito abdomen to salivary glands. Levels of viral diversity were maintained, however, by the regeneration of new SNVs at each stage of transmission. We further show that SNVs maintained across transmission stages were transmitted as a unit of two at maximum, suggesting the presence of numerous variant genomes carrying only one or two SNVs each. We also present evidence for differences in selection pressures between human and mosquito hosts, particularly on the structural and NS1 genes. This analysis provides insights into how population drops during transmission shape RNA virus genetic diversity, has direct implications for virus evolution, and illustrates the value of high-coverage, whole-genome next-generation sequencing for understanding viral intra-host genetic diversity.

  20. Low risk for transmission of zoonotic Giardia duodenalis from dogs to humans in rural Cambodia

    DEFF Research Database (Denmark)

    Inpankaew, Tawin; Schär, Fabian; Odermatt, Peter

    2014-01-01

    BACKGROUND: A number of epidemiological studies have demonstrated Giardia as prevalent in both humans and dogs worldwide and have postulated the occurrence of anthroponotic, zoonotic and animal-specific cycles of transmission, which may be geographically and regionally unique in its epidemiology.......: Overall, just over 2% of dogs harboured potentially zoonotic assemblages of G. duodenalis in the studied communities and hence pose a minimal zoonotic risk for the transmission of Giardia to humans.......BACKGROUND: A number of epidemiological studies have demonstrated Giardia as prevalent in both humans and dogs worldwide and have postulated the occurrence of anthroponotic, zoonotic and animal-specific cycles of transmission, which may be geographically and regionally unique in its epidemiology....... The aim of this study was to utilise molecular tools to determine the prevalence and compare genotypes of Giardia duodenalis infecting humans and dogs living in a previously identified Giardia-endemic village in rural Cambodia in order to ascertain zoonotic transmission risk. FINDINGS: The prevalence of G...

  1. Age patterns and transmission characteristics of hand, foot and mouth disease in China

    Directory of Open Access Journals (Sweden)

    Jijun Zhao

    2016-11-01

    Full Text Available Abstract Background Hand, foot and mouth disease (HFMD has circulated in China and caused yearly outbreak. To understand the transmission of the disease and to assess the spatial variation in cases reported, we examined age-specific transmission characteristics and reporting rates of HFMD for 31 provinces in mainland China. Methods We first analyzed incidence spatial patterns and age-specific incidence patterns using dataset from 2008 to 2012. Transmission characteristics were estimated based on catalytic model. Reporting rates were estimated using a simple mass action model from “Time Series Susceptible Infectious Recovered” (TSIR modeling. Results We found age-specific spatial incidence patterns: age-specific proportions of HFMD cases varied geographically in China; larger case percentage was among children of 3–5 years old in the northern part of China and was among children of 0–2 years old in the southern part of China. Our analysis results revealed that: 1 reporting rates and transmission characteristics including the average age at infection, the force of infection and the basic reproduction number varied geographically in China; 2 patterns of the age-specific force of infection for 30 provinces were similar to that of childhood infections in developed countries; the age group that had the highest infection risk was 3–5 years old in 30 provinces, and 10–14 years old in Tibet; 3 a large difference in HFMD transmission existed between northwest region and southeast region; 4 transmission characteristics determined incidence patterns: the higher the disease transmission in a province, the earlier the annual seasonality started and the more case percentage was among children 0–2 years old and less among 3–5 years old. Conclusion Because HFMD has higher transmission than most childhood infections reported, high effective vaccine coverage is needed to substantially reduce HFMD incidence. Control measures before the vaccine

  2. Computational modeling of interventions and protective thresholds to prevent disease transmission in deploying populations.

    Science.gov (United States)

    Burgess, Colleen; Peace, Angela; Everett, Rebecca; Allegri, Buena; Garman, Patrick

    2014-01-01

    Military personnel are deployed abroad for missions ranging from humanitarian relief efforts to combat actions; delay or interruption in these activities due to disease transmission can cause operational disruptions, significant economic loss, and stressed or exceeded military medical resources. Deployed troops function in environments favorable to the rapid and efficient transmission of many viruses particularly when levels of protection are suboptimal. When immunity among deployed military populations is low, the risk of vaccine-preventable disease outbreaks increases, impacting troop readiness and achievement of mission objectives. However, targeted vaccination and the optimization of preexisting immunity among deployed populations can decrease the threat of outbreaks among deployed troops. Here we describe methods for the computational modeling of disease transmission to explore how preexisting immunity compares with vaccination at the time of deployment as a means of preventing outbreaks and protecting troops and mission objectives during extended military deployment actions. These methods are illustrated with five modeling case studies for separate diseases common in many parts of the world, to show different approaches required in varying epidemiological settings.

  3. Computational Modeling of Interventions and Protective Thresholds to Prevent Disease Transmission in Deploying Populations

    Directory of Open Access Journals (Sweden)

    Colleen Burgess

    2014-01-01

    Full Text Available Military personnel are deployed abroad for missions ranging from humanitarian relief efforts to combat actions; delay or interruption in these activities due to disease transmission can cause operational disruptions, significant economic loss, and stressed or exceeded military medical resources. Deployed troops function in environments favorable to the rapid and efficient transmission of many viruses particularly when levels of protection are suboptimal. When immunity among deployed military populations is low, the risk of vaccine-preventable disease outbreaks increases, impacting troop readiness and achievement of mission objectives. However, targeted vaccination and the optimization of preexisting immunity among deployed populations can decrease the threat of outbreaks among deployed troops. Here we describe methods for the computational modeling of disease transmission to explore how preexisting immunity compares with vaccination at the time of deployment as a means of preventing outbreaks and protecting troops and mission objectives during extended military deployment actions. These methods are illustrated with five modeling case studies for separate diseases common in many parts of the world, to show different approaches required in varying epidemiological settings.

  4. Emerging Infectious Diseases and Blood Safety: Modeling the Transfusion-Transmission Risk.

    Science.gov (United States)

    Kiely, Philip; Gambhir, Manoj; Cheng, Allen C; McQuilten, Zoe K; Seed, Clive R; Wood, Erica M

    2017-07-01

    While the transfusion-transmission (TT) risk associated with the major transfusion-relevant viruses such as HIV is now very low, during the last 20 years there has been a growing awareness of the threat to blood safety from emerging infectious diseases, a number of which are known to be, or are potentially, transfusion transmissible. Two published models for estimating the transfusion-transmission risk from EIDs, referred to as the Biggerstaff-Petersen model and the European Upfront Risk Assessment Tool (EUFRAT), respectively, have been applied to several EIDs in outbreak situations. We describe and compare the methodological principles of both models, highlighting their similarities and differences. We also discuss the appropriateness of comparing results from the two models. Quantitating the TT risk of EIDs can inform decisions about risk mitigation strategies and their cost-effectiveness. Finally, we present a qualitative risk assessment for Zika virus (ZIKV), an EID agent that has caused several outbreaks since 2007. In the latest and largest ever outbreak, several probable cases of transfusion-transmission ZIKV have been reported, indicating that it is transfusion-transmissible and therefore a risk to blood safety. We discuss why quantitative modeling the TT risk of ZIKV is currently problematic. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  5. Abordagem nas doenças sexualmente transmissíveis Approach in sexually transmitted diseases

    Directory of Open Access Journals (Sweden)

    Walter Belda Junior

    2009-04-01

    Full Text Available As doenças sexualmente transmissíveis estão entre os problemas de saúde pública mais comuns em todo o mundo. Entre suas consequências estão a infertilidade feminina e masculina, a transmissão de mãe para filho, determinando perdas gestacionais ou doença congênita, e o aumento do risco para a infecção pelo HIV. Dessa forma, este guideline tem o objetivo de contribuir para melhorar a qualidade de atenção às pessoas com infecções sexualmente transmissíveis mais frequentes no Brasil, trazendo de forma didática e concreta o estado atual dos conhecimentos para os dermatologistas e médicos em geral que atuam no atendimento dessas pessoas e as principais recomendações para o diagnóstico e tratamento das doenças sexualmente transmissíveis mais recorrentes.Nowadays, sexually transmitted diseases are one of the most common public health issues. Among its consequences are the possibility of transmission from mother to baby - which may cause miscarriages and congenital disease, male and female infertility, and the increase of HIV infection risk. Therefore, the main goal of these guidelines is to contribute to the improvement of the treatment for sexually transmitted diseases patients by presenting to the medical community how today's science stands on the matter and also what the recommendation for diagnosing and treating a patient are.

  6. On the 2-Row Rule for Infectious Disease Transmission on Aircraft.

    Science.gov (United States)

    Hertzberg, Vicki Stover; Weiss, Howard

    With over two billion airline passengers annually, in-flight transmission of infectious diseases is an important global health concern. Many instances of in-flight transmission have been documented, but the relative influence of the many factors (see below) affecting in-flight transmission has not been quantified. Long-standing guidance by public health agencies is that the primary transmission risk associated with air travel for most respiratory infectious diseases is associated with sitting within two rows of an infectious passenger. The effect of proximity may be one of these factors. The aim of this study was to determine the risk of infection within and beyond the 2-row rule given by public health guidance. We searched the literature for reports of in-flight transmission of infection which included seat maps indicating where the infectious and infected passengers were seated. There is a ∼ 6% risk to passengers seated within the 2-rows of infected individual(s) and there is ∼ 2% risk to passengers seated beyond 2-rows from the infectious individual. Contact tracing limited to passengers within 2-rows of the infectious individual(s) could fail to detect other cases of infections. This has important consequences for assessing the spread of infectious diseases. Infection at a distance from the index case indicates other factors, such as airflow, movement of passenger/crew members, fomites and contacts between passengers in the departure gate before boarding, or after deplaning, are involved. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Chagas disease: current epidemiological trends after the interruption of vectorial and transfusional transmission in the Southern Cone countries.

    Science.gov (United States)

    Moncayo, Alvaro

    2003-07-01

    Chagas disease, named after Carlos Chagas who first described it in 1909, exists only on the American Continent. It is caused by a parasite, Trypanosoma cruzi, transmitted to humans by blood-sucking triatomine bugs and by blood transfusion. Chagas disease has two successive phases, acute and chronic. The acute phase lasts 6 to 8 weeks. After several years of starting the chronic phase, 20% to 35% of the infected individuals, depending on the geographical area will develop irreversible lesions of the autonomous nervous system in the heart, esophagus, colon and the peripheral nervous system. Data on the prevalence and distribution of Chagas disease improved in quality during the 1980's as a result of the demographically representative cross-sectional studies carried out in countries where accurate information was not available. A group of experts met in Bras lia in 1979 and devised standard protocols to carry out countrywide prevalence studies on human T. cruzi infection and triatomine house infestation. Thanks to a coordinated multi-country program in the Southern Cone countries the transmission of Chagas disease by vectors and by blood transfusion has been interrupted in Uruguay in1997, in Chile in 1999, and in 8 of the 12 endemic states of Brazil in 2000 and so the incidence of new infections by T. cruzi in the whole continent has decreased by 70%. Similar control multi-country initiatives have been launched in the Andean countries and in Central America and rapid progress has been recorded to ensure the interruption of the transmission of Chagas disease by 2005 as requested by a Resolution of the World Health Assembly approved in 1998. The cost-benefit analysis of the investments of the vector control program in Brazil indicate that there are savings of US$17 in medical care and disabilities for each dollar spent on prevention, showing that the program is a health investment with good return. Since the inception in 1979 of the Steering Committee on Chagas Disease

  8. [Diseases transmitted through water for human consumption].

    Science.gov (United States)

    Franco, E; Dentamaro, M

    2003-01-01

    The water for human consumption maintains a biological risk and can transmit diseases. The classical waterborne and the presently frequent diseases caused by protozoi Giardia and Cryptosporidium are considered and Arcobacter butzleri, a new waterborne pathogen, is described. Many measures have been adopted by institutions to ensure the quality of the drinking water. Managers and public health operators is working in order to verify the efficiency of more suitable indicators for its monitoring.

  9. Modeling human disease using organotypic cultures

    DEFF Research Database (Denmark)

    Schweiger, Pawel J; Jensen, Kim B

    2016-01-01

    animal models and in vitro cell culture systems. However, it has been exceedingly difficult to model disease at the tissue level. Since recently, the gap between cell line studies and in vivo modeling has been narrowing thanks to progress in biomaterials and stem cell research. Development of reliable 3D...... culture systems has enabled a rapid expansion of sophisticated in vitro models. Here we focus on some of the latest advances and future perspectives in 3D organoids for human disease modeling....

  10. Mouse Chromosome Engineering for Modeling Human Disease

    OpenAIRE

    van der Weyden, Louise; Bradley, Allan

    2006-01-01

    Chromosomal rearrangements occur frequently in humans and can be disease-associated or phenotypically neutral. Recent technological advances have led to the discovery of copy-number changes previously undetected by cytogenetic techniques. To understand the genetic consequences of such genomic changes, these mutations need to be modeled in experimentally tractable systems. The mouse is an excellent organism for this analysis because of its biological and genetic similarity to humans, and the e...

  11. Transplacental Transmission of Leishmania infantum as a Means for Continued Disease Incidence in North America

    OpenAIRE

    Boggiatto, Paola Mercedes; Gibson-Corley, Katherine Nicole; Metz, Kyle; Gallup, Jack Michael; Hostetter, Jesse Michael; Mullin, Kathleen; Petersen, Christine Anne

    2011-01-01

    Background Dogs are the predominant domestic reservoir for human L. infantum infection. Zoonotic visceral leishmaniasis (ZVL) is an emerging problem in some U.S. dog breeds, with an annual quantitative PCR prevalence of greater than 20% within an at-risk Foxhound population. Although classically Leishmania is transmitted by infected sand flies and phlebotomine sand flies exist in the United States, means of ongoing L. infantum transmission in U.S. dogs is currently unknown. Possibilities incl...

  12. Human Parasitic Diseases in Bulgaria in Between 2013-2014

    Science.gov (United States)

    Rainova, Iskra; Harizanov, Rumen; Kaftandjiev, Iskren; Tsvetkova, Nina; Mikov, Ognyan; Kaneva, Eleonora

    2018-01-01

    Background: In Bulgaria, more than 20 autochthonous human parasitic infections have been described and some of them are widespread. Over 50 imported protozoan and helminthic infections represent diagnostic and therapeutic challenges and pose epidemiological risks due to the possibility of local transmission. Aims: To establish the distribution of autochthonous and imported parasitic diseases among the population of the country over a 2-year period (2013-2014) and to evaluate their significance in the public health system. Study Design: Cross sectional study. Methods: We used the annual reports by regional health inspectorates and data from the National Reference Laboratory at the National Centre of Infectious and Parasitic Diseases on all individuals infected with parasitic diseases in the country. Prevalence was calculated for parasitic diseases with few or absent clinical manifestations (oligosymptomatic or asymptomatic infections). Incidence per 100.000 was calculated for diseases with an overt clinical picture or those that required hospitalisation and specialised medical interventions (e.g. surgery). Results: During the research period, parasitological studies were conducted on 1441.244 persons, and parasitic infections were diagnosed in 22.039 individuals. Distribution of various parasitic pathogens among the population displayed statistically significant differences in prevalence for some intestinal parasites (enterobiasis 0.81%, giardiasis 0.34% and blastocystosis 0.22%). For certain zoonotic diseases such as cystic echinococcosis (average incidence of 3.99 per 100.000) and trichinellosis (average incidence of 0.8 per 100.000), the incidence exceeds several times the annual incidence recorded in the European Union. Conclusion: Parasitic diseases still pose a substantial problem with social and medical impacts on the residents of our country. Improved efficiency regarding autochthonous and imported parasitic diseases is essential in providing the public

  13. Immunotherapy of Human Papilloma Virus Induced Disease

    Science.gov (United States)

    van der Burg, Sjoerd H

    2012-01-01

    Immunotherapy is the generic name for treatment modalities aiming to reinforce the immune system against diseases in which the immune system plays a role. The design of an optimal immunotherapeutic treatment against chronic viruses and associated diseases requires a detailed understanding of the interactions between the target virus and its host, in order to define the specific strategies that may have the best chance to deliver success at each stage of disease. Recently, a first series of successes was reported for the immunotherapy of Human Papilloma Virus (HPV)-induced premalignant diseases but there is definitely room for improvement. Here I discuss a number of topics that in my opinion require more study as the answers to these questions allows us to better understand the underlying mechanisms of disease and as such to tailor treatment. PMID:23341861

  14. The dangers of disease transmission by artificial insemination and embryo transfer.

    Science.gov (United States)

    Philpott, M

    1993-01-01

    This review summarizes the major infectious diseases of the three major agricultural species (cattle, sheep and pigs) and horses, and presents the evidence for and against the possibility of infectious agents being transmitted between animals via the venereal route or by the use of semen or early embryos in commercial artificial insemination (AI) or embryo transfer (ET). Cattle feature most prominently in the widespread distribution of frozen semen, and national and international organizations have set out guidelines to work towards disease-free bull studs with semen free from potential pathogens. With the control of major epizootic diseases, attention has been focused on such diseases as IBR, BVD and blue tongue, where clinical signs are rarely evident but the detection of virus in semen is of great importance. New information on the relevance of bacterial disease such as Mycobacterium paratuberculosis, campylobacteriosis and leptospirosis is reviewed, along with details of the mycoplasma and ureaplasma species of the bull's genital tract. Bovine spongiform encephalopathy (BSE) has attracted much research and semen is not regarded as a source of infection. New work on the pathogenesis of a number of diseases and the use of new biotechnology in diagnosis is included. The International Embryo Transfer Society (IETS) has encouraged a great deal of experimental work--much originating in Canada--on the risk of transmission of disease from donors to recipients via a 7-day-old blastocyst. There has been much success in demonstrating that with an approved protocol of handling the embryos, to date there is very little danger in disease transmission with both viruses and bacteria. The mycoplasma group appear more intractable and the role of BSE is still being evaluated. In sheep, scrapie, Brucella ovis infection and blue tongue feature in current work. In the pig there is a surge in international movement of pig semen, and Aujeszky's disease and the new so-called Blue Ear

  15. Risk of equine infectious disease transmission by non-race horse movements in Japan.

    Science.gov (United States)

    Hayama, Yoko; Kobayashi, Sota; Nishida, Takeshi; Nishiguchi, Akiko; Tsutsui, Toshiyuki

    2010-07-01

    For determining surveillance programs or infectious disease countermeasures, risk evaluation approaches have been recently undertaken in the field of animal health. In the present study, to help establish efficient and effective surveillance and countermeasures for equine infectious diseases, we evaluated the potential risk of equine infectious disease transmission in non-race horses from the viewpoints of horse movements and health management practices by conducting a survey of non-race horse holdings. From the survey, the non-race horse population was classified into the following five sectors based on their purposes: the equestrian sector, private owner sector, exhibition sector, fattening sector and others. Our survey results showed that the equestrian and private owner sectors had the largest population sizes, and movements between and within these sectors occurred quite frequently, while there was little movement in the other sectors. Qualitative evaluation showed that the equestrian and private owner sectors had relatively high risks of equine infectious disease transmission through horse movements. Therefore, it would be effective to concentrate on these two sectors when implementing surveillance or preventative measures. Special priority should be given to the private owner sector because this sector has not implemented inspection and vaccination well compared with the equestrian sector, which possesses a high compliance rate for these practices. This qualitative risk evaluation focused on horse movements and health management practices could provide a basis for further risk evaluation to establish efficient and effective surveillance and countermeasures for equine infectious diseases.

  16. Reduced penetrance in human inherited disease

    African Journals Online (AJOL)

    Rabah M. Shawky

    2014-01-31

    Jan 31, 2014 ... tant role in cellular senescence, tumorigenesis and in several diseases including type ... between epigenetic DNA modifications and human life span has also been shown .... penetrance mutation that is age dependent especially when compared with the ..... on healthy aging and longevity. Immunity Aging ...

  17. Primatology. Human diseases threaten great apes.

    Science.gov (United States)

    Ferber, D

    2000-08-25

    Researchers are uncovering disturbing evidence that scientists and tourists are infecting wild primates with human pathogens. In response, ape specialists, including the American Society of Primatologists, are now calling for stricter health standards for researchers and tourists. They are also urging researchers to learn how to diagnose disease in their study animals.

  18. High-frequency electroacupuncture evidently reinforces hippocampal synaptic transmission in Alzheimer's disease rats

    Science.gov (United States)

    Li, Wei; Kong, Li-hong; Wang, Hui; Shen, Feng; Wang, Ya-wen; Zhou, Hua; Sun, Guo-jie

    2016-01-01

    The frequency range of electroacupuncture in treatment of Alzheimer's disease in rats is commonly 2–5 Hz (low frequency) and 50–100 Hz (high frequency). We established a rat model of Alzheimer's disease by injecting β-amyloid 1–42 (Aβ1–42) into the bilateral hippocampal dentate gyrus to verify which frequency may be better suited in treatment. Electroacupuncture at 2 Hz or 50 Hz was used to stimulate Baihui (DU20) and Shenshu (BL23) acupoints. The water maze test and electrophysiological studies demonstrated that spatial memory ability was apparently improved, and the ranges of long-term potentiation and long-term depression were increased in Alzheimer's disease rats after electroacupuncture treatment. Moreover, the effects of electroacupuncture at 50 Hz were better than that at 2 Hz. These findings suggest that high-frequency electroacupuncture may enhance hippocampal synaptic transmission and potentially improve memory disorders in Alzheimer's disease rats. PMID:27335565

  19. Emerging arboviral human diseases in Southern Europe.

    Science.gov (United States)

    Papa, Anna

    2017-08-01

    Southern Europe is characterized by unique landscape and climate which attract tourists, but also arthropod vectors, some of them carrying pathogens. Among several arboviral diseases that emerged in the region during the last decade, West Nile fever accounted for high number of human cases and fatalities, while Crimean-Congo hemorrhagic fever expanded its geographic distribution, and is considered as a real threat for Europe. Viruses evolve rapidly and acquire mutations making themselves stronger and naive populations more vulnerable. In an effort to tackle efficiently the emerging arboviral diseases, preparedness and strategic surveillance are needed for the early detection of the pathogen and containment and mitigation of probable outbreaks. In this review, the main human arboviral diseases that emerged in Southern Europe are described. © 2017 Wiley Periodicals, Inc.

  20. Climate, environmental and socio-economic change: weighing up the balance in vector-borne disease transmission.

    Science.gov (United States)

    Parham, Paul E; Waldock, Joanna; Christophides, George K; Hemming, Deborah; Agusto, Folashade; Evans, Katherine J; Fefferman, Nina; Gaff, Holly; Gumel, Abba; LaDeau, Shannon; Lenhart, Suzanne; Mickens, Ronald E; Naumova, Elena N; Ostfeld, Richard S; Ready, Paul D; Thomas, Matthew B; Velasco-Hernandez, Jorge; Michael, Edwin

    2015-04-05

    Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is owing not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but also, perhaps most crucially, to the multitude of epidemiological, ecological and socio-economic factors that drive VBD transmission, and this complexity has generated considerable debate over the past 10-15 years. In this review, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions and, crucially, offer some solutions for the field. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector-pathogen systems. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  1. Climate, environmental and socio-economic change: weighing up the balance in vector-borne disease transmission

    Science.gov (United States)

    Parham, Paul E.; Waldock, Joanna; Christophides, George K.; Hemming, Deborah; Agusto, Folashade; Evans, Katherine J.; Fefferman, Nina; Gaff, Holly; Gumel, Abba; LaDeau, Shannon; Lenhart, Suzanne; Mickens, Ronald E.; Naumova, Elena N.; Ostfeld, Richard S.; Ready, Paul D.; Thomas, Matthew B.; Velasco-Hernandez, Jorge; Michael, Edwin

    2015-01-01

    Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is owing not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but also, perhaps most crucially, to the multitude of epidemiological, ecological and socio-economic factors that drive VBD transmission, and this complexity has generated considerable debate over the past 10–15 years. In this review, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions and, crucially, offer some solutions for the field. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector–pathogen systems. PMID:25688012

  2. Risk of transmission of sporadic Creutzfeldt-Jakob disease by surgical procedures: systematic reviews and quality of evidence.

    Science.gov (United States)

    López, Fernando J García; Ruiz-Tovar, María; Almazán-Isla, Javier; Alcalde-Cabero, Enrique; Calero, Miguel; de Pedro-Cuesta, Jesús

    2017-10-01

    Sporadic Creutzfeldt-Jakob disease (sCJD) is potentially transmissible to humans. This study aimed to summarise and rate the quality of the evidence of the association between surgery and sCJD. Firstly, we conducted systematic reviews and meta-analyses of case-control studies with major surgical procedures as exposures under study. To assess quality of evidence, we used the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. Secondly, we conducted a systematic review of sCJD case reports after sharing neurosurgical instruments. Thirteen case-control studies met the inclusion criteria for the systematic review of case-control studies. sCJD was positively associated with heart surgery, heart and vascular surgery and eye surgery, negatively associated with tonsillectomy and appendectomy, and not associated with neurosurgery or unspecified major surgery. The overall quality of evidence was rated as very low. A single case-control study with a low risk of bias found a strong association between surgery conducted more than 20 years before disease onset and sCJD. Seven cases were described as potentially transmitted by reused neurosurgical instruments. The association between surgery and sCJD remains uncertain. Measures currently recommended for preventing sCJD transmission should be strongly maintained. Future studies should focus on the potential association between sCJD and surgery undergone a long time previously.

  3. Human immunodeficiency virus type 1 mother-to-child transmission and prevention: successes and controversies.

    Science.gov (United States)

    Cavarelli, M; Scarlatti, G

    2011-12-01

    The World Health Organization (WHO) and United Nations Programme on HIV/AIDS (UNAIDS) estimated that an additional 370 000 new human immunodeficiency virus type 1 (HIV-1) infections occurred in children in 2009, mainly through mother-to-child transmission (MTCT). Intrapartum transmission contributes to approximately 20-25% of infections, in utero transmission to 5-10% and postnatal transmission to an additional 10-15% of cases. MTCT accounts for only a few hundred infected newborns in those countries in which services are established for voluntary counselling and testing of pregnant women, and a supply of antiretroviral drugs is available throughout pregnancy with recommendations for elective Caesarean section and avoidance of breastfeeding. The single-dose nevirapine regimen has provided the momentum to initiate MTCT programmes in many resource-limited countries; however, regimens using a combination of antiretroviral drugs are needed also to effectively reduce transmission via breastfeeding. 2011 The Association for the Publication of the Journal of Internal Medicine.

  4. Networks of infection : Online respondent-driven detection for studying infectious disease transmission and case finding

    NARCIS (Netherlands)

    Stein, ML

    2016-01-01

    A broad range of infectious diseases such as influenza, measles and Ebola are transmitted through direct or close human contact. These pathogens do not spread randomly through a population, but follow the structure of human contact networks. Making use of these networks may help to understand and

  5. Transmission of Human Respiratory Syncytial Virus in the Immunocompromised Ferret Model

    Science.gov (United States)

    de Waal, Leon; Smits, Saskia L.; Veldhuis Kroeze, Edwin J. B.; van Amerongen, Geert; Pohl, Marie O.; Osterhaus, Albert D. M. E.; Stittelaar, Koert J.

    2018-01-01

    Human respiratory syncytial virus (HRSV) causes substantial morbidity and mortality in vulnerable patients, such as the very young, the elderly, and immunocompromised individuals of any age. Nosocomial transmission of HRSV remains a serious challenge in hospital settings, with intervention strategies largely limited to infection control measures, including isolation of cases, high standards of hand hygiene, cohort nursing, and use of personal protective equipment. No vaccines against HRSV are currently available, and treatment options are largely supportive care and expensive monoclonal antibody or antiviral therapy. The limitations of current animal models for HRSV infection impede the development of new preventive and therapeutic agents, and the assessment of their potential for limiting HRSV transmission, in particular in nosocomial settings. Here, we demonstrate the efficient transmission of HRSV from immunocompromised ferrets to both immunocompromised and immunocompetent contact ferrets, with pathological findings reproducing HRSV pathology in humans. The immunocompromised ferret-HRSV model represents a novel tool for the evaluation of intervention strategies against nosocomial transmission of HRSV. PMID:29301313

  6. Inhibition of HIV transmission in human cervicovaginal explants and humanized mice using CD4 aptamer-siRNA chimeras

    Science.gov (United States)

    Wheeler, Lee Adam; Trifonova, Radiana; Vrbanac, Vladimir; Basar, Emre; McKernan, Shannon; Xu, Zhan; Seung, Edward; Deruaz, Maud; Dudek, Tim; Einarsson, Jon Ivar; Yang, Linda; Allen, Todd M.; Luster, Andrew D.; Tager, Andrew M.; Dykxhoorn, Derek M.; Lieberman, Judy

    2011-01-01

    The continued spread of the HIV epidemic underscores the need to interrupt transmission. One attractive strategy is a topical vaginal microbicide. Sexual transmission of herpes simplex virus type 2 (HSV-2) in mice can be inhibited by intravaginal siRNA application. To overcome the challenges of knocking down gene expression in immune cells susceptible to HIV infection, we used chimeric RNAs composed of an aptamer fused to an siRNA for targeted gene knockdown in cells bearing an aptamer-binding receptor. Here, we showed that CD4 aptamer-siRNA chimeras (CD4-AsiCs) specifically suppress gene expression in CD4+ T cells and macrophages in vitro, in polarized cervicovaginal tissue explants, and in the female genital tract of humanized mice. CD4-AsiCs do not activate lymphocytes or stimulate innate immunity. CD4-AsiCs that knock down HIV genes and/or CCR5 inhibited HIV infection in vitro and in tissue explants. When applied intravaginally to humanized mice, CD4-AsiCs protected against HIV vaginal transmission. Thus, CD4-AsiCs could be used as the active ingredient of a microbicide to prevent HIV sexual transmission. PMID:21576818

  7. Linking spring phenology with mechanistic models of host movement to predict disease transmission risk

    Science.gov (United States)

    Merkle, Jerod A.; Cross, Paul C.; Scurlock, Brandon M.; Cole, Eric K.; Courtemanch, Alyson B.; Dewey, Sarah R.; Kauffman, Matthew J.

    2018-01-01

    Disease models typically focus on temporal dynamics of infection, while often neglecting environmental processes that determine host movement. In many systems, however, temporal disease dynamics may be slow compared to the scale at which environmental conditions alter host space-use and accelerate disease transmission.Using a mechanistic movement modelling approach, we made space-use predictions of a mobile host (elk [Cervus Canadensis] carrying the bacterial disease brucellosis) under environmental conditions that change daily and annually (e.g., plant phenology, snow depth), and we used these predictions to infer how spring phenology influences the risk of brucellosis transmission from elk (through aborted foetuses) to livestock in the Greater Yellowstone Ecosystem.Using data from 288 female elk monitored with GPS collars, we fit step selection functions (SSFs) during the spring abortion season and then implemented a master equation approach to translate SSFs into predictions of daily elk distribution for five plausible winter weather scenarios (from a heavy snow, to an extreme winter drought year). We predicted abortion events by combining elk distributions with empirical estimates of daily abortion rates, spatially varying elk seroprevelance and elk population counts.Our results reveal strong spatial variation in disease transmission risk at daily and annual scales that is strongly governed by variation in host movement in response to spring phenology. For example, in comparison with an average snow year, years with early snowmelt are predicted to have 64% of the abortions occurring on feedgrounds shift to occurring on mainly public lands, and to a lesser extent on private lands.Synthesis and applications. Linking mechanistic models of host movement with disease dynamics leads to a novel bridge between movement and disease ecology. Our analysis framework offers new avenues for predicting disease spread, while providing managers tools to proactively mitigate

  8. Role of the Environment in the Transmission of Antimicrobial Resistance to Humans: A Review.

    Science.gov (United States)

    Huijbers, Patricia M C; Blaak, Hetty; de Jong, Mart C M; Graat, Elisabeth A M; Vandenbroucke-Grauls, Christina M J E; de Roda Husman, Ana Maria

    2015-10-20

    To establish a possible role for the natural environment in the transmission of clinically relevant AMR bacteria to humans, a literature review was conducted to systematically collect and categorize evidence for human exposure to extended-spectrum β-lactamase-producing Enterobacteriaceae, methicillin-resistant Staphylococcus aureus, and vancomycin-resistant Enterococcus spp. in the environment. In total, 239 datasets adhered to inclusion criteria. AMR bacteria were detected at exposure-relevant sites (35/38), including recreational areas, drinking water, ambient air, and shellfish, and in fresh produce (8/16). More datasets were available for environmental compartments (139/157), including wildlife, water, soil, and air/dust. Quantitative data from exposure-relevant sites (6/35) and environmental compartments (11/139) were scarce. AMR bacteria were detected in the contamination sources (66/66) wastewater and manure, and molecular data supporting their transmission from wastewater to the environment (1/66) were found. The abundance of AMR bacteria at exposure-relevant sites suggests risk for human exposure. Of publications pertaining to both environmental and human isolates, however, only one compared isolates from samples that had a clear spatial and temporal relationship, and no direct evidence was found for transmission to humans through the environment. To what extent the environment, compared to the clinical and veterinary domains, contributes to human exposure needs to be quantified. AMR bacteria in the environment, including sites relevant for human exposure, originate from contamination sources. Intervention strategies targeted at these sources could therefore limit emission of AMR bacteria to the environment.

  9. Nodule worm infection in humans and wild primates in Uganda: cryptic species in a newly identified region of human transmission.

    Directory of Open Access Journals (Sweden)

    Ria R Ghai

    Full Text Available Soil-transmitted helminths (STHs are a major health concern in tropical and sub-tropical countries. Oesophagostomum infection is considered endemic to West Africa but has also been identified in Uganda, East Africa, among primates (including humans. However, the taxonomy and ecology of Oesophagostomum in Uganda have not been studied, except for in chimpanzees (Pan troglodytes, which are infected by both O. bifurcum and O. stephanostomum.We studied Oesophagostomum in Uganda in a community of non-human primates that live in close proximity to humans. Prevalence estimates based on microscopy were lower than those based on polymerase chain reaction (PCR, indicating greater sensitivity of PCR. Prevalence varied among host species, with humans and red colobus (Procolobus rufomitratus infected at lowest prevalence (25% and 41% by PCR, respectively, and chimpanzees, olive baboons (Papio anubis, and l'hoest monkeys (Cercopithecus lhoesti infected at highest prevalence (100% by PCR in all three species. Phylogenetic regression showed that primates travelling further and in smaller groups are at greatest risk of infection. Molecular phylogenetic analyses revealed three cryptic clades of Oesophagostomum that were not distinguishable based on morphological characteristics of their eggs. Of these, the clade with the greatest host range had not previously been described genetically. This novel clade infects humans, as well as five other species of primates.Multiple cryptic forms of Oesophagostomum circulate in the people and primates of western Uganda, and parasite clades differ in host range and cross-species transmission potential. Our results expand knowledge about human Oesophagostomum infection beyond the West African countries of Togo and Ghana, where the parasite is a known public health concern. Oesophagostomum infection in humans may be common throughout Sub-Saharan Africa, and the transmission of this neglected STH among primates, including zoonotic

  10. Burden of Disease Attributed to Waterborne Transmission of Selected Enteric Pathogens, Australia, 2010.

    Science.gov (United States)

    Gibney, Katherine B; O'Toole, Joanne; Sinclair, Martha; Leder, Karin

    2017-06-01

    AbstractUniversal access to safe drinking water is a global priority. To estimate the annual disease burden of campylobacteriosis, nontyphoidal salmonellosis, cryptosporidiosis, giardiasis, and norovirus attributable to waterborne transmission in Australia, we multiplied regional World Health Organization (WHO) estimates of the proportion of cases attributable to waterborne transmission by estimates of all-source disease burden for each study pathogen. Norovirus was attributed as causing the most waterborne disease cases (479,632; 95% uncertainty interval [UI]: 0-1,111,874) followed by giardiasis and campylobacteriosis. The estimated waterborne disability-adjusted life year (DALY) burden for campylobacteriosis (2,004; 95% UI: 0-5,831) was 7-fold greater than other study pathogens and exceeded the WHO guidelines for drinking water quality (1 × 10 -6 DALY per person per year) by 90-fold. However, these estimates include disease transmitted via either drinking or recreational water exposure. More precise country-specific and drinking water-specific attribution estimates would better define the health burden from drinking water and inform changes to treatment requirements.

  11. Global dynamics of multi-group SEI animal disease models with indirect transmission

    International Nuclear Information System (INIS)

    Wang, Yi; Cao, Jinde

    2014-01-01

    A challenge to multi-group epidemic models in mathematical epidemiology is the exploration of global dynamics. Here we formulate multi-group SEI animal disease models with indirect transmission via contaminated water. Under biologically motivated assumptions, the basic reproduction number R 0 is derived and established as a sharp threshold that completely determines the global dynamics of the system. In particular, we prove that if R 0 <1, the disease-free equilibrium is globally asymptotically stable, and the disease dies out; whereas if R 0 >1, then the endemic equilibrium is globally asymptotically stable and thus unique, and the disease persists in all groups. Since the weight matrix for weighted digraphs may be reducible, the afore-mentioned approach is not directly applicable to our model. For the proofs we utilize the classical method of Lyapunov, graph-theoretic results developed recently and a new combinatorial identity. Since the multiple transmission pathways may correspond to the real world, the obtained results are of biological significance and possible generalizations of the model are also discussed

  12. Where Public Health Meets Human Rights: Integrating Human Rights into the Validation of the Elimination of Mother-to-Child Transmission of HIV and Syphilis.

    Science.gov (United States)

    Kismödi, Eszter; Kiragu, Karusa; Sawicki, Olga; Smith, Sally; Brion, Sophie; Sharma, Aditi; Mworeko, Lilian; Iovita, Alexandrina

    2017-12-01

    In 2014, the World Health Organization (WHO) initiated a process for validation of the elimination of mother-to-child transmission (EMTCT) of HIV and syphilis by countries. For the first time in such a process for the validation of disease elimination, WHO introduced norms and approaches that are grounded in human rights, gender equality, and community engagement. This human rights-based validation process can serve as a key opportunity to enhance accountability for human rights protection by evaluating EMTCT programs against human rights norms and standards, including in relation to gender equality and by ensuring the provision of discrimination-free quality services. The rights-based validation process also involves the assessment of participation of affected communities in EMTCT program development, implementation, and monitoring and evaluation. It brings awareness to the types of human rights abuses and inequalities faced by women living with, at risk of, or affected by HIV and syphilis, and commits governments to eliminate those barriers. This process demonstrates the importance and feasibility of integrating human rights, gender, and community into key public health interventions in a manner that improves health outcomes, legitimizes the participation of affected communities, and advances the human rights of women living with HIV.

  13. Tensile force transmission in human patellar tendon fascicles is not mediated by glycosaminoglycans

    DEFF Research Database (Denmark)

    Svensson, René B; Hassenkam, Tue; Hansen, Philip

    2011-01-01

    suggested that the proteoglycan-associated glycosaminoglycans (GAGs) found on the surface of the collagen fibrils may be an important transmitter of load, but existing results are ambiguous and have not investigated human tendons. We have used a small-scale mechanical testing system to measure...... change the tendon modulus, relative energy dissipation, peak stress, or peak strain. The effect of deformation rate was not modulated by the treatment either, indicating no effect on viscosity. These results suggest that GAGs cannot be considered mediators of tensile force transmission in the human...... patellar tendon, and as such, force transmission must either take place through other matrix components or the fibrils must be mechanically continuous at least to the tested length of 7 mm....

  14. Transmission of foot-and-mouth disease virus during the incubation period in pigs

    Directory of Open Access Journals (Sweden)

    Carolina Stenfeldt

    2016-11-01

    Full Text Available Understanding the quantitative characteristics of a pathogen’s capability to transmit during distinct phases of infection is important to enable accurate predictions of the spread and impact of a disease outbreak. In the current investigation, the potential for transmission of foot-and-mouth disease virus (FMDV during the incubation (preclinical phase of infection was investigated in seven groups of pigs that were sequentially exposed to a group of donor pigs that were infected by simulated-natural inoculation. Contact-exposed pigs were co-mingled with infected donors through successive eight-hour time slots spanning from 8 to 64 hours post inoculation (hpi of the donor pigs. The transition from latent to infectious periods in the donor pigs was clearly defined by successful transmission of foot-and-mouth disease (FMD to all contact pigs that were exposed to the donors from 24 hpi and later. This onset of infectiousness occurred concurrent with detection of viremia, but approximately 24 hours prior to the first appearance of clinical signs of FMD in the donors.Thus, the latent period of infection ended approximately 24 hours earlier than the end of the incubation period. There were significant differences between contact-exposed groups in the time elapsed from virus exposure to the first detection of FMDV shedding, viremia and clinical lesions. Specifically, the onset and progression of clinical FMD was more rapid in pigs that had been exposed to the donor pigs during more advanced phases of disease, suggesting that these animals had received a higher effective challenge dose. These results demonstrate transmission and dissemination of FMD within groups of pigs during the incubation period of infection. Furthermore, the findings suggest that under current conditions, shedding of FMDV in oropharyngeal fluids is a more precise proxy for FMDV infectiousness than clinical signs of infection. These findings may impact modeling of the propagation of

  15. The evolution of wealth transmission in human populations: a stochastic model

    International Nuclear Information System (INIS)

    Augustins, G; Etienne, L; Ferrer, R; Godelle, B; Rousset, F; Ferdy, J-B; Pitard, E

    2014-01-01

    Reproductive success and survival are influenced by wealth in human populations. Wealth is transmitted to offsprings and strategies of transmission vary over time and among populations, the main variation being how equally wealth is transmitted to children. Here we propose a model where we simulate both the dynamics of wealth in a population and the evolution of a trait that determines how wealth is transmitted from parents to offspring, in a darwinian context

  16. Best Practices for Preventing Vector-Borne Diseases in Dogs and Humans.

    Science.gov (United States)

    Dantas-Torres, Filipe; Otranto, Domenico

    2016-01-01

    Vector-borne diseases constitute a diversified group of illnesses, which are caused by a multitude of pathogens transmitted by arthropod vectors, such as mosquitoes, fleas, ticks, and sand flies. Proper management of these diseases is important from both human and veterinary medicine standpoints, given that many of these pathogens are transmissible to humans and dogs, which often live in close contact. In this review, we summarize the most important vector-borne diseases of dogs and humans and the best practices for their prevention. The control of these diseases would ultimately improve animal and human health and wellbeing, particularly in developing countries in the tropics, where the risk of these diseases is high and access to health care is poor. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock

    Science.gov (United States)

    Kamath, Pauline L.; Foster, Jeffrey T.; Drees, Kevin P.; Luikart, Gordon; Quance, Christine; Anderson, Neil J.; Clarke, P. Ryan; Cole, Eric K.; Drew, Mark L.; Edwards, William H.; Rhyan, Jack C.; Treanor, John J.; Wallen, Rick L.; White, Patrick J.; Robbe-Austerman, Suelee; Cross, Paul C.

    2016-01-01

    Whole-genome sequencing has provided fundamental insights into infectious disease epidemiology, but has rarely been used for examining transmission dynamics of a bacterial pathogen in wildlife. In the Greater Yellowstone Ecosystem (GYE), outbreaks of brucellosis have increased in cattle along with rising seroprevalence in elk. Here we use a genomic approach to examine Brucella abortus evolution, cross-species transmission and spatial spread in the GYE. We find that brucellosis was introduced into wildlife in this region at least five times. The diffusion rate varies among Brucella lineages (B3 to 8 km per year) and over time. We also estimate 12 host transitions from bison to elk, and 5 from elk to bison. Our results support the notion that free-ranging elk are currently a self-sustaining brucellosis reservoir and the source of livestock infections, and that control measures in bison are unlikely to affect the dynamics of unrelated strains circulating in nearby elk populations.

  18. First field trial of a transmissible recombinant vaccine against myxomatosis and rabbit hemorrhagic disease.

    Science.gov (United States)

    Torres, J M; Sánchez, C; Ramírez, M A; Morales, M; Bárcena, J; Ferrer, J; Espuña, E; Pagès-Manté, A; Sánchez-Vizcaíno, J M

    2001-08-14

    As a novel approach for immunisation of wild rabbits, we have recently developed a transmissible vaccine against myxomatosis and rabbit hemorrhagic disease (RHD) based on a recombinant myxoma virus (MV) expressing the RHDV capsid protein [J. Virol. 74 (2000) 1114]. The efficacy and safety of the vaccine have been extensively evaluated under laboratory conditions. In this study, we report the first limited field trial of the candidate vaccine that was undertaken in an island of 34 Has containing a population of around 300 rabbits. Following administration by the subcutaneous route to 76 rabbits, the vaccine induced specific antibody responses against both myxomatosis and RHDV in all the inoculated rabbits. Furthermore, the recombinant virus exhibited a limited horizontal transmission capacity, promoting seroconversion of around 50% of the uninoculated rabbit population. No evidence of undesirable effects due to the recombinant virus field release was detected.

  19. Horizontal transmissible protection against myxomatosis and rabbit hemorrhagic disease by using a recombinant myxoma virus.

    Science.gov (United States)

    Bárcena, J; Morales, M; Vázquez, B; Boga, J A; Parra, F; Lucientes, J; Pagès-Manté, A; Sánchez-Vizcaíno, J M; Blasco, R; Torres, J M

    2000-02-01

    We have developed a new strategy for immunization of wild rabbit populations against myxomatosis and rabbit hemorrhagic disease (RHD) that uses recombinant viruses based on a naturally attenuated field strain of myxoma virus (MV). The recombinant viruses expressed the RHDV major capsid protein (VP60) including a linear epitope tag from the transmissible gastroenteritis virus (TGEV) nucleoprotein. Following inoculation, the recombinant viruses induced specific antibody responses against MV, RHDV, and the TGEV tag. Immunization of wild rabbits by the subcutaneous and oral routes conferred protection against virulent RHDV and MV challenges. The recombinant viruses showed a limited horizontal transmission capacity, either by direct contact or in a flea-mediated process, promoting immunization of contact uninoculated animals.

  20. Human endogenous retroviruses in neurologic disease.

    Science.gov (United States)

    Christensen, Tove

    2016-01-01

    Endogenous retroviruses are pathogenic - in other species than the human. Disease associations for Human Endogenous RetroViruses (HERVs) are emerging, but so far an unequivocal pathogenetic cause-effect relationship has not been established. A role for HERVs has been proposed in neurological and neuropsychiatric diseases as diverse as multiple sclerosis (MS) and schizophrenia (SCZ). Particularly for MS, many aspects of the activation and involvement of specific HERV families (HERV-H/F and HERV-W/MSRV) have been reported, both for cells in the circulation and in the central nervous system. Notably envelope genes and their gene products (Envs) appear strongly associated with the disease. For SCZ, for ALS, and for HIV-associated dementia (HAD), indications are accumulating for involvement of the HERV-K family, and also HERV-H/F and/or HERV-W. Activation is reasonably a prerequisite for causality as most HERV sequences remain quiescent in non-pathological conditions, so the importance of regulatory pathways and epigenetics involved in regulating HERV activation, derepression, and also involvement of retroviral restriction factors, is emerging. HERV-directed antiretrovirals have potential as novel therapeutic paradigms in neurologic disease, particularly in MS. The possible protective or ameliorative effects of antiretroviral therapy in MS are substantiated by reports that treatment of HIV infection may be associated with a significantly decreased risk of MS. Further studies of HERVs, their role in neurologic diseases, and their potential as therapeutic targets are essential. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  1. Chains of transmission and control of Ebola Virus Disease in Conakry, Guinea in 2014

    Science.gov (United States)

    Faye, Ousmane; Boëlle, Pierre-Yves; Heleze, Emmanuel; Faye, Oumar; Loucoubar, Cheikh; Magassouba, N’Faly; Soropogui, Barré; Keita, Sakoba; Gakou, Tata; Bah, El Hadji Ibrahima; Koivogui, Lamine; Sall, Amadou Alpha; Cauchemez, Simon

    2015-01-01

    Background An Ebola Virus Disease (EVD) epidemic of unprecedented magnitude is ongoing in West Africa, affecting for the first time large urban centers like Conakry, the capital of Guinea. Methods Interviews of EVD patients, relatives and neighbors and laboratory databases were used to reconstruct EVD chains of transmission in Conakry, from March to August 2014. Findings Out of 193 confirmed and probable EVD cases reported in Conakry, Boffa and Télimélé, 152 (79%) were positioned in the chains of transmission. In March, non-Health Care Workers cases infected on average 2.3 (95% CI: 1.6, 3.2) persons, breaking down into 1.4 (95% CI: 0.9, 2.2) persons in the community, 0.4 (95% CI: 0.1, 0.9) in the hospital and 0.5 (95% CI: 0.2, 1.0) at funerals. Following implementation of infection control in April, the reproduction number in the hospital and at funerals reduced below 0.1. In the community, the reproduction number, which was positively correlated with patients viremia, dropped by 50% for hospitalized cases but remained unchanged for those not hospitalized. Hospital and funeral transmission represented 35% (7/20) and 15% (3/20) of all transmissions in March; but only 9% (11/128) and 4% (5/128) from April onward. Overall, 82% (119/145) of transmission occurred in the community and 72% (105/145) between family members. Simulations showed that a 10% increase in hospitalizations could have reduced the length of chains by 26% (95% CI: 4%, 45%). Interpretation Monitoring chains of transmission is critical to evaluate and optimize local control strategies for EVD. In Conakry, interventions had the potential to stop the epidemic but reintroductions of the disease and lack of cooperation of a small number of families led to prolonged low-level spread, highlighting challenges of EVD control in large urban centers. Funding Labex IBEID, Reacting, PREDEMICS, NIGMS MIDAS initiative, Institut Pasteur de Dakar. PMID:25619149

  2. Estimating transmission of avian influenza in wild birds from incomplete epizootic data: implications for surveillance and disease spreac

    Science.gov (United States)

    Henaux, Viviane; Jane Parmley,; Catherine Soos,; Samuel, Michael D.

    2013-01-01

    Estimating disease transmission in wildlife populations is critical to understand host–pathogen dynamics, predict disease risks and prioritize surveillance activities. However, obtaining reliable estimates for free-ranging populations is extremely challenging. In particular, disease surveillance programs may routinely miss the onset or end of epizootics and peak prevalence, limiting the ability to evaluate infectious processes.

  3. Chagas Disease in Ecuador: Evidence for Disease Transmission in an Indigenous Population in the Amazon Region

    Directory of Open Access Journals (Sweden)

    Chico H Martha

    1997-01-01

    Full Text Available Two well-defined synthetic peptides TcD and PEP2 were used in a sero-epidemiological study for the detection of Trypanosoma cruzi infections in an indigenous group in the Amazon region of Ecuador. Of the 18 communities studied along the Río Napo, province of Napo, 15 (83.3% were found to be positive for T. cruzi infection. Of the 1,011 individuals examined 61 (6.03% resulted positive. A prevalence of infection of 4.8% was found in children aged 1-5 years. The prevalence of infection increased with age, with adults 50 years or older showing a maximum prevalence of 18.8%. Autochthonous transmission of T. cruzi is present among this isolated indigenous population

  4. Complete-proteome mapping of human influenza A adaptive mutations: implications for human transmissibility of zoonotic strains.

    Science.gov (United States)

    Miotto, Olivo; Heiny, A T; Albrecht, Randy; García-Sastre, Adolfo; Tan, Tin Wee; August, J Thomas; Brusic, Vladimir

    2010-02-03

    There is widespread concern that H5N1 avian influenza A viruses will emerge as a pandemic threat, if they become capable of human-to-human (H2H) transmission. Avian strains lack this capability, which suggests that it requires important adaptive mutations. We performed a large-scale comparative analysis of proteins from avian and human strains, to produce a catalogue of mutations associated with H2H transmissibility, and to detect their presence in avian isolates. We constructed a dataset of influenza A protein sequences from 92,343 public database records. Human and avian sequence subsets were compared, using a method based on mutual information, to identify characteristic sites where human isolates present conserved mutations. The resulting catalogue comprises 68 characteristic sites in eight internal proteins. Subtype variability prevented the identification of adaptive mutations in the hemagglutinin and neuraminidase proteins. The high number of sites in the ribonucleoprotein complex suggests interdependence between mutations in multiple proteins. Characteristic sites are often clustered within known functional regions, suggesting their functional roles in cellular processes. By isolating and concatenating characteristic site residues, we defined adaptation signatures, which summarize the adaptive potential of specific isolates. Most adaptive mutations emerged within three decades after the 1918 pandemic, and have remained remarkably stable thereafter. Two lineages with stable internal protein constellations have circulated among humans without reassorting. On the contrary, H5N1 avian and swine viruses reassort frequently, causing both gains and losses of adaptive mutations. Human host adaptation appears to be complex and systemic, involving nearly all influenza proteins. Adaptation signatures suggest that the ability of H5N1 strains to infect humans is related to the presence of an unusually high number of adaptive mutations. However, these mutations appear

  5. Experimental Study of Dispersion and Deposition of Expiratory Aerosols in Aircraft Cabins and Impact on Infectious Disease Transmission

    DEFF Research Database (Denmark)

    To, G.N.S.; Wan, M.P.; Chao, C.Y.H.

    2009-01-01

    The dispersion and deposition characteristics of polydispersed expiratory aerosols were investigated in an aircraft cabin mockup to study the transmission of infectious diseases. The airflow was characterized by particle image velocimetry (PIV) measurements. Aerosol dispersionwas measured...

  6. Molecular biology of human muscle disease

    Energy Technology Data Exchange (ETDEWEB)

    Dunne, P.W.; Epstein, H.F. (Baylor Coll. of Medicine, Houston, TX (United States))

    1991-01-01

    The molecular revolution that is transforming the entire biomedical field has had far-reaching impact in its application to inherited human muscle disease. The gene for Duchenne muscular dystrophy was one of the first cloned without knowledge of the defective protein product. This success was based upon the availability of key chromosomal aberrations that provided molecular landmarks for the disease locus. Subsequent discoveries regarding the mode of expression for this gene, the structure and localization of its protein product dystrophin, and molecular diagnosis of affected and carrier individuals constitute a paradigm for investigation of human genetics. Finding the gene for myotonic muscular dystrophy is requiring the brute force approach of cloning several million bases of DNA, identifying expressed sequences, and characterizing candidate genes. The gene that causes hypertrophic cardiomyopathy has been found serendipitously to be one of the genetic markers on chromosome 14, the {beta} myosin heavy chain.

  7. Seroprevalence of Antibodies against Plasmodium falciparum Sporozoite Antigens as Predictive Disease Transmission Markers in an Area of Ghana with Seasonal Malaria Transmission.

    Directory of Open Access Journals (Sweden)

    Kwadwo A Kusi

    Full Text Available As an increasing number of malaria-endemic countries approach the disease elimination phase, sustenance of control efforts and effective monitoring are necessary to ensure success. Mathematical models that estimate anti-parasite antibody seroconversion rates are gaining relevance as more sensitive transmission intensity estimation tools. Models however estimate yearly seroconversion and seroreversion rates and usually predict long term changes in transmission, occurring years before the time of sampling. Another challenge is the identification of appropriate antigen targets since specific antibody levels must directly reflect changes in transmission patterns. We therefore investigated the potential of antibodies to sporozoite and blood stage antigens for detecting short term differences in malaria transmission in two communities in Northern Ghana with marked, seasonal transmission.Cross-sectional surveys were conducted during the rainy and dry seasons in two communities, one in close proximity to an irrigation dam and the other at least 20 Km away from the dam. Antibodies against the sporozoite-specific antigens circumsporozoite protein (CSP and Cell traversal for ookinetes and sporozoites (CelTOS and the classical blood stage antigen apical membrane antigen 1 (AMA1 were measured by indirect ELISA. Antibody levels and seroprevalence were compared between surveys and between study communities. Antibody seroprevalence data were fitted to a modified reversible catalytic model to estimate the seroconversion and seroreversion rates.Changes in sporozoite-specific antibody levels and seroprevalence directly reflected differences in parasite prevalence between the rainy and dry seasons and hence the extent of malaria transmission. Seroconversion rate estimates from modelled seroprevalence data did not however support the above observation.The data confirms the potential utility of sporozoite-specific antigens as useful markers for monitoring short term

  8. The nuclear envelopathies and human diseases

    Directory of Open Access Journals (Sweden)

    Jeang Kuan-Teh

    2009-10-01

    Full Text Available Abstract The nuclear envelope (NE consists of two membrane layers that segregate the nuclear from the cytoplasmic contents. Recent progress in our understanding of nuclear-lamina associated diseases has revealed intriguing connections between the envelope components and nuclear processes. Here, we review the functions of the nuclear envelope in chromosome organization, gene expression, DNA repair and cell cycle progression, and correlate deficiencies in envelope function with human pathologies.

  9. Surveillance for Neisseria meningitidis Disease Activity and Transmission Using Information Technology.

    Directory of Open Access Journals (Sweden)

    S Sohail Ahmed

    Full Text Available While formal reporting, surveillance, and response structures remain essential to protecting public health, a new generation of freely accessible, online, and real-time informatics tools for disease tracking are expanding the ability to raise earlier public awareness of emerging disease threats. The rationale for this study is to test the hypothesis that the HealthMap informatics tools can complement epidemiological data captured by traditional surveillance monitoring systems for meningitis due to Neisseria meningitides (N. meningitides by highlighting severe transmissible disease activity and outbreaks in the United States.Annual analyses of N. meningitides disease alerts captured by HealthMap were compared to epidemiological data captured by the Centers for Disease Control's Active Bacterial Core surveillance (ABCs for N. meningitides. Morbidity and mortality case reports were measured annually from 2010 to 2013 (HealthMap and 2005 to 2012 (ABCs.HealthMap N. meningitides monitoring captured 80-90% of alerts as diagnosed N. meningitides, 5-20% of alerts as suspected cases, and 5-10% of alerts as related news articles. HealthMap disease alert activity for emerging disease threats related to N. meningitides were in agreement with patterns identified historically using traditional surveillance systems. HealthMap's strength lies in its ability to provide a cumulative "snapshot" of weak signals that allows for rapid dissemination of knowledge and earlier public awareness of potential outbreak status while formal testing and confirmation for specific serotypes is ongoing by public health authorities.The underreporting of disease cases in internet-based data streaming makes inadequate any comparison to epidemiological trends illustrated by the more comprehensive ABCs network published by the Centers for Disease Control. However, the expected delays in compiling confirmatory reports by traditional surveillance systems (at the time of writing, ABCs data

  10. Three pathogens in sympatric populations of pumas, bobcats, and domestic cats: implications for infectious disease transmission.

    Directory of Open Access Journals (Sweden)

    Sarah N Bevins

    Full Text Available Anthropogenic landscape change can lead to increased opportunities for pathogen transmission between domestic and non-domestic animals. Pumas, bobcats, and domestic cats are sympatric in many areas of North America and share many of the same pathogens, some of which are zoonotic. We analyzed bobcat, puma, and feral domestic cat samples collected from targeted geographic areas. We examined exposure to three pathogens that are taxonomically diverse (bacterial, protozoal, viral, that incorporate multiple transmission strategies (vector-borne, environmental exposure/ingestion, and direct contact, and that vary in species-specificity. Bartonella spp., Feline Immunodeficiency Virus (FIV, and Toxoplasma gondii IgG were detected in all three species with mean respective prevalence as follows: puma 16%, 41% and 75%; bobcat 31%, 22% and 43%; domestic cat 45%, 10% and 1%. Bartonella spp. were highly prevalent among domestic cats in Southern California compared to other cohort groups. Feline Immunodeficiency Virus exposure was primarily associated with species and age, and was not influenced by geographic location. Pumas were more likely to be infected with FIV than bobcats, with domestic cats having the lowest infection rate. Toxoplasma gondii seroprevalence was high in both pumas and bobcats across all sites; in contrast, few domestic cats were seropositive, despite the fact that feral, free ranging domestic cats were targeted in this study. Interestingly, a directly transmitted species-specific disease (FIV was not associated with geographic location, while exposure to indirectly transmitted diseases--vector-borne for Bartonella spp. and ingestion of oocysts via infected prey or environmental exposure for T. gondii--varied significantly by site. Pathogens transmitted by direct contact may be more dependent upon individual behaviors and intra-specific encounters. Future studies will integrate host density, as well as landscape features, to better

  11. Three pathogens in sympatric populations of pumas, bobcats, and domestic cats: Implications for infections disease transmission

    Science.gov (United States)

    Bevins, Sarah N.; Carver, Scott; Boydston, Erin E.; Lyren, Lisa M.; Alldredge, Mat; Logan, Kenneth A.; Riley, Seth P.D.; Fisher, Robert N.; Vickers, T. Winston; Boyce, Walter; Salman, Mo; Lappin, Michael R.; Crooks, Kevin R.; VandeWoude, Sue

    2012-01-01

    Anthropogenic landscape change can lead to increased opportunities for pathogen transmission between domestic and non-domestic animals. Pumas, bobcats, and domestic cats are sympatric in many areas of North America and share many of the same pathogens, some of which are zoonotic. We analyzed bobcat, puma, and feral domestic cat samples collected from targeted geographic areas. We examined exposure to three pathogens that are taxonomically diverse (bacterial, protozoal, viral), that incorporate multiple transmission strategies (vector-borne, environmental exposure/ingestion, and direct contact), and that vary in species-specificity. Bartonella spp., Feline Immunodeficiency Virus (FIV), and Toxoplasma gondii IgG were detected in all three species with mean respective prevalence as follows: puma 16%, 41% and 75%; bobcat 31%, 22% and 43%; domestic cat 45%, 10% and 1%. Bartonella spp. were highly prevalent among domestic cats in Southern California compared to other cohort groups. Feline Immunodeficiency Virus exposure was primarily associated with species and age, and was not influenced by geographic location. Pumas were more likely to be infected with FIV than bobcats, with domestic cats having the lowest infection rate. Toxoplasma gondii seroprevalence was high in both pumas and bobcats across all sites; in contrast, few domestic cats were seropositive, despite the fact that feral, free ranging domestic cats were targeted in this study. Interestingly, a directly transmitted species-specific disease (FIV) was not associated with geographic location, while exposure to indirectly transmitted diseases – vector-borne for Bartonella spp. and ingestion of oocysts via infected prey or environmental exposure for T. gondii – varied significantly by site. Pathogens transmitted by direct contact may be more dependent upon individual behaviors and intra-specific encounters. Future studies will integrate host density, as well as landscape features, to better

  12. Humanized Mouse Model of Ebola Virus Disease Mimics the Immune Responses in Human Disease.

    Science.gov (United States)

    Bird, Brian H; Spengler, Jessica R; Chakrabarti, Ayan K; Khristova, Marina L; Sealy, Tara K; Coleman-McCray, JoAnn D; Martin, Brock E; Dodd, Kimberly A; Goldsmith, Cynthia S; Sanders, Jeanine; Zaki, Sherif R; Nichol, Stuart T; Spiropoulou, Christina F

    2016-03-01

    Animal models recapitulating human Ebola virus disease (EVD) are critical for insights into virus pathogenesis. Ebola virus (EBOV) isolates derived directly from human specimens do not, without adaptation, cause disease in immunocompetent adult rodents. Here, we describe EVD in mice engrafted with human immune cells (hu-BLT). hu-BLT mice developed EVD following wild-type EBOV infection. Infection with high-dose EBOV resulted in rapid, lethal EVD with high viral loads, alterations in key human antiviral immune cytokines and chemokines, and severe histopathologic findings similar to those shown in the limited human postmortem data available. A dose- and donor-dependent clinical course was observed in hu-BLT mice infected with lower doses of either Mayinga (1976) or Makona (2014) isolates derived from human EBOV cases. Engraftment of the human cellular immune system appeared to be essential for the observed virulence, as nonengrafted mice did not support productive EBOV replication or develop lethal disease. hu-BLT mice offer a unique model for investigating the human immune response in EVD and an alternative animal model for EVD pathogenesis studies and therapeutic screening. Published by Oxford University Press for the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  13. [Unconventional disease agents--a danger for humans and animals?].

    Science.gov (United States)

    Kaaden, O R

    1994-02-01

    The occurrence of bovine spongiform encephalopathy (BSE) in Great Britain in 1985/86, has focused again the public concern as well as scientific interest to the Scrapie disease of sheep and goat known more than 150 years. The agents of scrapie and BSE are characterized by unusual biological and physical-chemical properties, especially their high tenacity. Therefore, they are also designated "unconventional agents of viruses". Different theories have been proposed about their infectious characteristics--especially because of the apparent or real missing of an agent-specific nucleic acid--which are named Virinos, Prions or Nemavirus. The broad host range of Scrapie respective BSE, which includes domestic and wild ruminants, Suidae, Felidae, Mustelidae, small rodents, birds and non-primates, has created some concern since there might be an aetiological correlation between the transmissible spongiform encephalopathies of man (Creutzfeld-Jakob- and Gerstmann-Sträussler-Scheinker-Disease) and that of animals. Although at present neither epidemiological nor molecular biological evidence whatsoever was proved, the hypothesis cannot be completely disproved. The probability of infection through digestive tract seems to be rather unlikely but special precautions should be taken as far as production, investigation and application of human medicine drugs of animal origin. Furthermore, research about the aetiology of "unconventional agents" and pathogenesis of resulting diseases is necessary and should be intensified in Germany. Finally, only an early intra vitam-Diagnose and in vitro detection can avoid an further spread of this new category of diseases.

  14. The role of chemerin in human disease

    Directory of Open Access Journals (Sweden)

    Magdalena Stojek

    2017-02-01

    Full Text Available Adipose tissue is not merely a storage depot of triacylglycerols but also a major endocrine organ. Its cells, including adipocytes, synthesize and secrete a range of biologically active molecules termed adipokines. Adipokines that display the properties of cytokines are often called adipocytokines. In recent years there has been increasing interest in a new adipokine called chemerin. Chemerin is a protein synthesized mostly by the adipose tissue and the liver as inactive pre-pro-chemerin. After the intracellular hydrolytic cutting off of the 20-amino-acid N-terminal polypeptide, it is secreted into the bloodstream as inactive pro-chemerin. Biologically active chemerin is then derived from pro-chemerin after cleavage of the C-terminal fragment by serum proteases involved in inflammation, coagulation and fibrinolysis. Proteolytic cleavage leads to formation of several chemerin-derived peptides, both biologically active (often with opposing functions and inactive.Within the last decade, there has been a growing number of publications regarding the role of chemerin in human disease. It seems to be implicated in the inflammatory response, metabolic syndrome, cardiovascular disease and alimentary tract disorders. The article presents the most recent information on the role of chemerin in human disease, and specifically alimentary tract disorders. The available evidence suggests that chemerin is an important link between adipose tissue mass, metabolic processes, the immune system and inflammation, and therefore plays a major role in human pathophysiology.

  15. Foot-and-mouth disease in British deer: transmission of virus to cattle, sheep and deer.

    Science.gov (United States)

    Gibbs, E P; Herniman, K A; Lawman, M J; Sellers, R F

    1975-06-28

    After exposure for two hours to cattle with foot-and-mouth disease, each of the five species of deer found in the British countryside became infected. Clinical disease was typical and severe in the roe and muntjac deer, with some animals dying, less severe in the sika deer and usually subclinical in the fallow and red deer. Each species transmitted disease to its own species and to cattle and sheep. The amounts of virus present in the blood, and in oesophageal/pharyngeal samples and excreted as an aerosol during the course of the infection in the deer were similar to those recorded for the sheep and cattle in the same experiment. The fallow and sika deer commonly carried virus in the pharynx beyond 28 days after exposure; some red deer also became carriers. In epidemics of foot-and-mouth disease in the UK, it is likely that deer would have such intimate contact with farm animals as occurred in this study. The natural behavior of free-living deer in the UK suggests that, although the five species are susceptible to foot-and-mouth disease, they are unlikely to be an important factor in the maintenance and transmission of the virus during an epidemic of foot-and-mouth disease in domestic livestock.

  16. Towards Chagas disease elimination: Neonatal screening for congenital transmission in rural communities.

    Science.gov (United States)

    Pennington, Pamela Marie; Juárez, José Guillermo; Arrivillaga, Margarita Rivera; De Urioste-Stone, Sandra María; Doktor, Katherine; Bryan, Joe P; Escobar, Clara Yaseli; Cordón-Rosales, Celia

    2017-09-01

    Chagas disease is a neglected tropical disease that continues to affect populations living in extreme poverty in Latin America. After successful vector control programs, congenital transmission remains as a challenge to disease elimination. We used the PRECEDE-PROCEED planning model to develop strategies for neonatal screening of congenital Chagas disease in rural communities of Guatemala. These communities have persistent high triatomine infestations and low access to healthcare. We used mixed methods with multiple stakeholders to identify and address maternal-infant health behaviors through semi-structured interviews, participatory group meetings, archival reviews and a cross-sectional survey in high risk communities. From December 2015 to April 2016, we jointly developed a strategy to illustratively advertise newborn screening at the Health Center. The strategy included socioculturally appropriate promotional and educational material, in collaboration with midwives, nurses and nongovernmental organizations. By March 2016, eight of 228 (3.9%) pregnant women had been diagnosed with T. cruzi at the Health Center. Up to this date, no neonatal screening had been performed. By August 2016, seven of eight newborns born to Chagas seropositive women had been parasitologically screened at the Health Center, according to international standards. Thus, we implemented a successful community-based neonatal screening strategy to promote congenital Chagas disease healthcare in a rural setting. The success of the health promotion strategies developed will depend on local access to maternal-infant services, integration with detection of other congenital diseases and reliance on community participation in problem and solution definition.

  17. Towards Chagas disease elimination: Neonatal screening for congenital transmission in rural communities.

    Directory of Open Access Journals (Sweden)

    Pamela Marie Pennington

    2017-09-01

    Full Text Available Chagas disease is a neglected tropical disease that continues to affect populations living in extreme poverty in Latin America. After successful vector control programs, congenital transmission remains as a challenge to disease elimination. We used the PRECEDE-PROCEED planning model to develop strategies for neonatal screening of congenital Chagas disease in rural communities of Guatemala. These communities have persistent high triatomine infestations and low access to healthcare. We used mixed methods with multiple stakeholders to identify and address maternal-infant health behaviors through semi-structured interviews, participatory group meetings, archival reviews and a cross-sectional survey in high risk communities. From December 2015 to April 2016, we jointly developed a strategy to illustratively advertise newborn screening at the Health Center. The strategy included socioculturally appropriate promotional and educational material, in collaboration with midwives, nurses and nongovernmental organizations. By March 2016, eight of 228 (3.9% pregnant women had been diagnosed with T. cruzi at the Health Center. Up to this date, no neonatal screening had been performed. By August 2016, seven of eight newborns born to Chagas seropositive women had been parasitologically screened at the Health Center, according to international standards. Thus, we implemented a successful community-based neonatal screening strategy to promote congenital Chagas disease healthcare in a rural setting. The success of the health promotion strategies developed will depend on local access to maternal-infant services, integration with detection of other congenital diseases and reliance on community participation in problem and solution definition.

  18. Programming of maternal and offspring disease: impact of growth restriction, fetal sex and transmission across generations.

    Science.gov (United States)

    Cheong, Jean N; Wlodek, Mary E; Moritz, Karen M; Cuffe, James S M

    2016-09-01

    Babies born small are at an increased risk of developing myriad adult diseases. While growth restriction increases disease risk in all individuals, often a second hit is required to unmask 'programmed' impairments in physiology. Programmed disease outcomes are demonstrated more commonly in male offspring compared with females, with these sex-specific outcomes partly attributed to different placenta-regulated growth strategies of the male and female fetus. Pregnancy is known to be a major risk factor for unmasking a number of conditions and can be considered a 'second hit' for women who were born small. As such, female offspring often develop impairments of physiology for the first time during pregnancy that present as pregnancy complications. Numerous maternal stressors can further increase the risk of developing a maternal complication during pregnancy. Importantly, these maternal complications can have long-term consequences for both the mother after pregnancy and the developing fetus. Conditions such as preeclampsia, gestational diabetes and hypertension as well as thyroid, liver and kidney diseases are all conditions that can complicate pregnancy and have long-term consequences for maternal and offspring health. Babies born to mothers who develop these conditions are often at a greater risk of developing disease in adulthood. This has implications as a mechanism for transmission of disease across generations. In this review, we discuss the evidence surrounding long-term intergenerational implications of being born small and/or experiencing stress during pregnancy on programming outcomes. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

  19. Human immunodeficiency virus-induced pathology favored by cellular transmission and activation

    International Nuclear Information System (INIS)

    Lewis, D.E.; Yoffe, B.; Bosworth, C.G.; Hollinger, F.B.; Rich, R.R.

    1988-01-01

    Epidemiological data suggest that transmission of human immunodeficiency virus (HIV) occurs primarily by transference of virally infected cells. However, the efficiency of lytic productive infection induced by HIV after transmission of cell-associated virus vs. free virus is difficult to assess. The present studies compare the extent of depletion of CD4+ (helper/inducer) T cells after mixing uninfected cells with either free HIV or irradiated HIV-infected allogeneic or autologous cells in vitro. Rapid CD4+ cellular depletion occurred only in cultures containing allogeneic infected cells or after addition of a nonspecific T cell activation signal to cultures with autologous infected cells. These in vitro observations strongly support the epidemiological implication that interactions between infected and uninfected cells are the most efficient means of transmission and HIV-induced cytopathology in vivo. They also provide direct support for the concept that immunological stimulation by foreign cells infected with HIV dramatically increases the likelihood of transmission. These in vitro observations suggest a model for the acquisition of HIV in vivo and the role of cellular activation in dissemination of the virus to uninfected cells in an infected individual

  20. Disease prevalence and transmission of Microsporidium phytoseiuli infecting the predatory mite, Phytoseiulus persimilis (Acari: Phytoseiidae).

    Science.gov (United States)

    Bjørnson, S; Keddie, B A

    2001-02-01

    Isolated colonies of the predatory mite, Phytoseiulus persimilis, were used to gain information regarding prevalence and transmission of Microsporidium phytoseiuli. Two colonies of P. persimilis were reared on spider mite (Tetranychus urticae)-infested bean plants in isolated cages. Disease prevalence of predators from Colony 1 remained relatively low (between 0 and 15%) over 57 weeks of observation whereas disease prevalence of predators from Colony 2 increased over 3 months (from 12 to 100%). Disease prevalence among predators from Colony 1 had increased to 100% 2 months after weekly sampling had ceased for this colony and periodic sampling confirmed that disease prevalence among individuals of both colonies remained at 100%. Microsporidian spores were not detected in randomly chosen samples of T. urticae prey mites that were removed and examined biweekly during this period. Although numerous microsporidian spores were observed in smear preparations of fecal pellets examined by light microscopy, spores were not observed on leaf surfaces or predator feces when examined by SEM. The latter appeared as intact aggregates composed of numerous dumbbell-shaped crystals and it is unlikely that spores are liberated from intact fecal pellets onto leaf surfaces. Vertical transmission of M. phytoseiuli was 100%; horizontal transmission was low (14.3%) and occurred only when immature P. persimilis were permitted to develop in contact with infected immature and adult predators. The mean number of eggs produced per mated pair was highest when uninfected females were mated with uninfected males (63.2 eggs per mated pair). Although mean egg production decreased when one or both parents were infected, not all differences were significant. Male predatory mites did not contribute to infection of their progeny. Results suggest that routine examination of P. persimilis for microsporidian spores is essential for the management of M. phytoseiuli within P. persimilis colonies. Low disease

  1. epidemix—An interactive multi-model application for teaching and visualizing infectious disease transmission

    Directory of Open Access Journals (Sweden)

    Ulrich Muellner

    2018-06-01

    Full Text Available Mathematical models of disease transmission are used to improve our understanding of patterns of infection and to identify factors influencing them. During recent public and animal health crises, such as pandemic influenza, Ebola, Zika, foot-and-mouth disease, models have made important contributions in addressing policy questions, especially through the assessment of the trajectory and scale of outbreaks, and the evaluation of control interventions. However, their mathematical formulation means that they may appear as a “black box” to those without the appropriate mathematical background. This may lead to a negative perception of their utility for guiding policy, and generate expectations, which are not in line with what these models can deliver. It is therefore important for policymakers, as well as public health and animal health professionals and researchers who collaborate with modelers and use results generated by these models for policy development or research purpose, to understand the key concepts and assumptions underlying these models.The software application epidemix (http://shinyapps.rvc.ac.uk presented here aims to make mathematical models of disease transmission accessible to a wider audience of users. By developing a visual interface for a suite of eight models, users can develop an understanding of the impact of various modelling assumptions – especially mixing patterns – on the trajectory of an epidemic and the impact of control interventions, without having to directly deal with the complexity of mathematical equations and programming languages. Models are compartmental or individual-based, deterministic or stochastic, and assume homogeneous or heterogeneous-mixing patterns (with the probability of transmission depending on the underlying structure of contact networks, or the spatial distribution of hosts. This application is intended to be used by scientists teaching mathematical modelling short courses to non

  2. Transmission of chronic wasting disease identifies a prion strain causing cachexia and heart infection in hamsters.

    Directory of Open Access Journals (Sweden)

    Richard A Bessen

    Full Text Available Chronic wasting disease (CWD is an emerging prion disease of free-ranging and captive cervids in North America. In this study we established a rodent model for CWD in Syrian golden hamsters that resemble key features of the disease in cervids including cachexia and infection of cardiac muscle. Following one to three serial passages of CWD from white-tailed deer into transgenic mice expressing the hamster prion protein gene, CWD was subsequently passaged into Syrian golden hamsters. In one passage line there were preclinical changes in locomotor activity and a loss of body mass prior to onset of subtle neurological symptoms around 340 days. The clinical symptoms included a prominent wasting disease, similar to cachexia, with a prolonged duration. Other features of CWD in hamsters that were similar to cervid CWD included the brain distribution of the disease-specific isoform of the prion protein, PrP(Sc, prion infection of the central and peripheral neuroendocrine system, and PrP(Sc deposition in cardiac muscle. There was also prominent PrP(Sc deposition in the nasal mucosa on the edge of the olfactory sensory epithelium with the lumen of the nasal airway that could have implications for CWD shedding into nasal secretions and disease transmission. Since the mechanism of wasting disease in prion diseases is unknown this hamster CWD model could provide a means to investigate the physiological basis of cachexia, which we propose is due to a prion-induced endocrinopathy. This prion disease phenotype has not been described in hamsters and we designate it as the 'wasting' or WST strain of hamster CWD.

  3. Two profitless delays for an SEIRS epidemic disease model with vertical transmission and pulse vaccination

    International Nuclear Information System (INIS)

    Meng Xinzhu; Jiao Jianjun; Chen Lansun

    2009-01-01

    Since the investigation of impulsive delay differential equations is beginning, the literature on delay epidemic models with pulse vaccination is not extensive. In this paper, we propose a new SEIRS epidemic disease model with two profitless delays and vertical transmission, and analyze the dynamics behaviors of the model under pulse vaccination. Using the discrete dynamical system determined by the stroboscopic map, we obtain a 'infection-free' periodic solution, further, show that the 'infection-free' periodic solution is globally attractive when some parameters of the model are under appropriate conditions. Using a new modeling method, we obtain sufficient condition for the permanence of the epidemic model with pulse vaccination. We show that time delays, pulse vaccination and vertical transmission can bring different effects on the dynamics behaviors of the model by numerical analysis. Our results also show the delays are 'profitless'. In this paper, the main feature is to introduce two discrete time delays, vertical transmission and impulse into SEIRS epidemic model and to give pulse vaccination strategies.

  4. No Effect of TETRA Hand Portable Transmission Signals on Human Cognitive Function and Symptoms

    DEFF Research Database (Denmark)

    Riddervold, Ingunn Skogstad; Kjærgaard, Søren K.; Pedersen, Gert F.

    2010-01-01

    Current radio frequency radiation exposure guidelines rest on well-established thermal effects. However, recent research into analogue and digital transmission fields at levels covered by the exposure guidelines has indicated possible detrimental effects on human cognitive performance. To investi......Current radio frequency radiation exposure guidelines rest on well-established thermal effects. However, recent research into analogue and digital transmission fields at levels covered by the exposure guidelines has indicated possible detrimental effects on human cognitive performance....... To investigate this, we conducted a controlled climate chamber study of possible changes in cognitive performance in healthy volunteers exposed to transmission signals from TETRA hand portables (TETRA handsets). The trial deployed a balanced, randomized, double-blinded cross-over design. Performance on different...... paper-and-pencil, auditory and computer-based cognitive tasks was monitored in 53 male volunteers (mean age 36.41 years, SD 8.35) during 45-min exposure to a TETRA handset and sham control signals remotely controlled from a laboratory more than 100 km away. The main cognitive outcome was the Trail...

  5. Epidemic Wave Dynamics Attributable to Urban Community Structure: A Theoretical Characterization of Disease Transmission in a Large Network

    Science.gov (United States)

    Eggo, Rosalind M; Lenczner, Michael

    2015-01-01

    Background Multiple waves of transmission during infectious disease epidemics represent a major public health challenge, but the ecological and behavioral drivers of epidemic resurgence are poorly understood. In theory, community structure—aggregation into highly intraconnected and loosely interconnected social groups—within human populations may lead to punctuated outbreaks as diseases progress from one community to the next. However, this explanation has been largely overlooked in favor of temporal shifts in environmental conditions and human behavior and because of the difficulties associated with estimating large-scale contact patterns. Objective The aim was to characterize naturally arising patterns of human contact that are capable of producing simulated epidemics with multiple wave structures. Methods We used an extensive dataset of proximal physical contacts between users of a public Wi-Fi Internet system to evaluate the epidemiological implications of an empirical urban contact network. We characterized the modularity (community structure) of the network and then estimated epidemic dynamics under a percolation-based model of infectious disease spread on the network. We classified simulated epidemics as multiwave using a novel metric and we identified network structures that were critical to the network’s ability to produce multiwave epidemics. Results We identified robust community structure in a large, empirical urban contact network from which multiwave epidemics may emerge naturally. This pattern was fueled by a special kind of insularity in which locally popular individuals were not the ones forging contacts with more distant social groups. Conclusions Our results suggest that ordinary contact patterns can produce multiwave epidemics at the scale of a single urban area without the temporal shifts that are usually assumed to be responsible. Understanding the role of community structure in epidemic dynamics allows officials to anticipate epidemic

  6. A model-based clustering method to detect infectious disease transmission outbreaks from sequence variation.

    Directory of Open Access Journals (Sweden)

    Rosemary M McCloskey

    2017-11-01

    Full Text Available Clustering infections by genetic similarity is a popular technique for identifying potential outbreaks of infectious disease, in part because sequences are now routinely collected for clinical management of many infections. A diverse number of nonparametric clustering methods have been developed for this purpose. These methods are generally intuitive, rapid to compute, and readily scale with large data sets. However, we have found that nonparametric clustering methods can be biased towards identifying clusters of diagnosis-where individuals are sampled sooner post-infection-rather than the clusters of rapid transmission that are meant to be potential foci for public health efforts. We develop a fundamentally new approach to genetic clustering based on fitting a Markov-modulated Poisson process (MMPP, which represents the evolution of transmission rates along the tree relating different infections. We evaluated this model-based method alongside five nonparametric clustering methods using both simulated and actual HIV sequence data sets. For simulated clusters of rapid transmission, the MMPP clustering method obtained higher mean sensitivity (85% and specificity (91% than the nonparametric methods. When we applied these clustering methods to published sequences from a study of HIV-1 genetic clusters in Seattle, USA, we found that the MMPP method categorized about half (46% as many individuals to clusters compared to the other methods. Furthermore, the mean internal branch lengths that approximate transmission rates were significantly shorter in clusters extracted using MMPP, but not by other methods. We determined that the computing time for the MMPP method scaled linearly with the size of trees, requiring about 30 seconds for a tree of 1,000 tips and about 20 minutes for 50,000 tips on a single computer. This new approach to genetic clustering has significant implications for the application of pathogen sequence analysis to public health, where

  7. Transmissible Spongiform Encephalopathy and Meat Safety

    Science.gov (United States)

    Ward, Hester J. T.; Knight, Richard S. G.

    Prion diseases or transmissible spongiform encephalopathies (TSEs) comprise a wide-ranging group of neurodegenerative diseases found in animals and humans. They have diverse causes and geographical distributions, but have similar pathological features, transmissibility and, are ultimately, fatal. Central to all TSEs is the presence of an abnormal form of a normal host protein, namely the prion protein. Because of their potential transmissibility, these diseases have wide public health ramifications.

  8. Pathogenesis, Transmissibility, and Tropism of a Highly Pathogenic Avian Influenza A(H7N7) Virus Associated With Human Conjunctivitis in Italy, 2013.

    Science.gov (United States)

    Belser, Jessica A; Creager, Hannah M; Zeng, Hui; Maines, Taronna R; Tumpey, Terrence M

    2017-09-15

    H7 subtype influenza viruses represent a persistent public health threat because of their continued detection in poultry and ability to cause human infection. An outbreak of highly pathogenic avian influenza H7N7 virus in Italy during 2013 resulted in 3 cases of human conjunctivitis. We determined the pathogenicity and transmissibility of influenza A/Italy/3/2013 virus in mouse and ferret models and examined the replication kinetics of this virus in several human epithelial cell types. The moderate virulence observed in mammalian models and the capacity for transmission in a direct contact model underscore the need for continued study of H7 subtype viruses. Published by Oxford University Press for the Infectious Diseases Society of America 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  9. Insect Peptides - Perspectives in Human Diseases Treatment.

    Science.gov (United States)

    Chowanski, Szymon; Adamski, Zbigniew; Lubawy, Jan; Marciniak, Pawel; Pacholska-Bogalska, Joanna; Slocinska, Malgorzata; Spochacz, Marta; Szymczak, Monika; Urbanski, Arkadiusz; Walkowiak-Nowicka, Karolina; Rosinski, Grzegorz

    2017-01-01

    Insects are the largest and the most widely distributed group of animals in the world. Their diversity is a source of incredible variety of different mechanisms of life processes regulation. There are many agents that regulate immunology, reproduction, growth and development or metabolism. Hence, it seems that insects may be a source of numerous substances useful in human diseases treatment. Especially important in the regulation of insect physiology are peptides, like neuropeptides, peptide hormones or antimicrobial peptides. There are two main aspects where they can be helpful, 1) Peptides isolated from insects may become potential drugs in therapy of different diseases, 2) A lot of insect peptide hormones show structural or functional homology to mammalian peptide hormones and the comparative studies may give a new look on human disorders. In our review we focused on three group of insect derived peptides: 1) immune-active peptides, 2) peptide hormones and 3) peptides present in venoms. In our review we try to show the considerable potential of insect peptides in searching for new solutions for mammalian diseases treatment. We summarise the knowledge about properties of insect peptides against different virulent agents, anti-inflammatory or anti-nociceptive properties as well as compare insect and mammalian/vertebrate peptide endocrine system to indicate usefulness of knowledge about insect peptide hormones in drug design. The field of possible using of insect delivered peptide to therapy of various human diseases is still not sufficiently explored. Undoubtedly, more attention should be paid to insects due to searching new drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  10. The draft genome sequence of the ferret (Mustela putorius furo) facilitates study of human respiratory disease.

    Science.gov (United States)

    Peng, Xinxia; Alföldi, Jessica; Gori, Kevin; Eisfeld, Amie J; Tyler, Scott R; Tisoncik-Go, Jennifer; Brawand, David; Law, G Lynn; Skunca, Nives; Hatta, Masato; Gasper, David J; Kelly, Sara M; Chang, Jean; Thomas, Matthew J; Johnson, Jeremy; Berlin, Aaron M; Lara, Marcia; Russell, Pamela; Swofford, Ross; Turner-Maier, Jason; Young, Sarah; Hourlier, Thibaut; Aken, Bronwen; Searle, Steve; Sun, Xingshen; Yi, Yaling; Suresh, M; Tumpey, Terrence M; Siepel, Adam; Wisely, Samantha M; Dessimoz, Christophe; Kawaoka, Yoshihiro; Birren, Bruce W; Lindblad-Toh, Kerstin; Di Palma, Federica; Engelhardt, John F; Palermo, Robert E; Katze, Michael G

    2014-12-01

    The domestic ferret (Mustela putorius furo) is an important animal model for multiple human respiratory diseases. It is considered the 'gold standard' for modeling human influenza virus infection and transmission. Here we describe the 2.41 Gb draft genome assembly of the domestic ferret, constituting 2.28 Gb of sequence plus gaps. We annotated 19,910 protein-coding genes on this assembly using RNA-seq data from 21 ferret tissues. We characterized the ferret host response to two influenza virus infections by RNA-seq analysis of 42 ferret samples from influenza time-course data and showed distinct signatures in ferret trachea and lung tissues specific to 1918 or 2009 human pandemic influenza virus infections. Using microarray data from 16 ferret samples reflecting cystic fibrosis disease progression, we showed that transcriptional changes in the CFTR-knockout ferret lung reflect pathways of early disease that cannot be readily studied in human infants with cystic fibrosis disease.

  11. Mule deer spatial association patterns and potential implications for transmission of an epizootic disease.

    Directory of Open Access Journals (Sweden)

    María Fernanda Mejía-Salazar

    disease transmission among mule deer.

  12. Visual Darkness Reduces Perceived Risk of Contagious-Disease Transmission From Interpersonal Interaction.

    Science.gov (United States)

    Dong, Ping; Zhong, Chen-Bo

    2018-05-01

    We examined the psychological impact of visual darkness on people's perceived risk of contagious-disease transmission. We posited that darkness triggers an abstract construal level and increases perceived social distance from others, rendering threats from others to seem less relevant to the self. We found that participants staying in a dimly lit room (Studies 1 and 3-5) or wearing sunglasses (Study 2) tended to estimate a lower risk of catching contagious diseases from others than did those staying in a brightly lit room or wearing clear glasses. The effect persisted in both laboratory (Studies 1-4) and real-life settings (Study 5). The effect arises because visual darkness elevates perceived social distance from the contagion (Study 3) and is attenuated among abstract (vs. concrete) thinkers (Study 4). These findings delineate a systematic, unconscious influence of visual darkness-a subtle yet pervasive situational factor-on perceived risk of contagion. Theoretical contributions and policy implications are discussed.

  13. Histochemical approaches to assess cell-to-cell transmission of misfolded proteins in neurodegenerative diseases

    Directory of Open Access Journals (Sweden)

    G. Natale

    2013-03-01

    Full Text Available Formation, aggregation and transmission of abnormal proteins are common features in neurodegenerative disorders including Parkinson’s disease, Alzheimer’s disease, amyotrophic lateral sclerosis, and Huntington’s disease. The mechanisms underlying protein alterations in neurodegenerative diseases remain controversial. Novel findings highlighted altered protein clearing systems as common biochemical pathways which generate protein misfolding, which in turn causes protein aggregation and protein spreading. In fact, proteinaceous aggregates are prone to cell-to-cell propagation. This is reminiscent of what happens in prion disorders, where the prion protein misfolds thus forming aggregates which spread to neighbouring cells. For this reason, the term prionoids is currently used to emphasize how several misfolded proteins are transmitted in neurodegenerative diseases following this prion-like pattern. Histochemical techniques including the use of specific antibodies covering both light and electron microscopy offer a powerful tool to describe these phenomena and investigate specific molecular steps. These include: prion like protein alterations; glycation of prion-like altered proteins to form advanced glycation end-products (AGEs; mechanisms of extracellular secretion; interaction of AGEs with specific receptors placed on neighbouring cells (RAGEs. The present manuscript comments on these phenomena aimed to provide a consistent scenario of the available histochemical approaches to dissect each specific step.

  14. Clozapine and GABA transmission in schizophrenia disease models: establishing principles to guide treatments.

    Science.gov (United States)

    O'Connor, William T; O'Shea, Sean D

    2015-06-01

    Schizophrenia disease models are necessary to elucidate underlying changes and to establish new therapeutic strategies towards a stage where drug efficacy in schizophrenia (against all classes of symptoms) can be predicted. Here we summarise the evidence for a GABA dysfunction in schizophrenia and review the functional neuroanatomy of five pathways implicated in schizophrenia, namely the mesocortical, mesolimbic, ventral striopallidal, dorsal striopallidal and perforant pathways including the role of local GABA transmission and we describe the effect of clozapine on local neurotransmitter release. This review also evaluates psychotropic drug-induced, neurodevelopmental and environmental disease models including their compatibility with brain microdialysis. The validity of disease models including face, construct, etiological and predictive validity and how these models constitute theories about this illness is also addressed. A disease model based on the effect of the abrupt withdrawal of clozapine on GABA release is also described. The review concludes that while no single animal model is entirely successful in reproducing schizophreniform symptomatology, a disease model based on an ability to prevent and/or reverse the abrupt clozapine discontinuation-induced changes in GABA release in brain regions implicated in schizophrenia may be useful for hypothesis testing and for in vivo screening of novel ligands not limited to a single pharmacological class. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. The effects of demographic change on disease transmission and vaccine impact in a household structured population.

    Science.gov (United States)

    Geard, Nicholas; Glass, Kathryn; McCaw, James M; McBryde, Emma S; Korb, Kevin B; Keeling, Matt J; McVernon, Jodie

    2015-12-01

    The demographic structure of populations in both more developed and less developed countries is changing: increases in life expectancy and declining fertility have led to older populations and smaller households. The implications of these demographic changes for the spread and control of infectious diseases are not fully understood. Here we use an individual based model with realistic and dynamic age and household structure to demonstrate the marked effect that demographic change has on disease transmission at the population and household level. The decline in fertility is associated with a decrease in disease incidence and an increase in the age of first infection, even in the absence of vaccination or other control measures. Although large households become rarer as fertility decreases, we show that there is a proportionate increase in incidence of disease in these households as the accumulation of susceptible clusters increases the potential for explosive outbreaks. By modelling vaccination, we provide a direct comparison of the relative importance of demographic change and vaccination on incidence of disease. We highlight the increased risks associated with unvaccinated households in a low fertility setting if vaccine behaviour is correlated with household membership. We suggest that models that do not account for future demographic change, and especially its effect on household structure, may potentially overestimate the impact of vaccination. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  16. Group A Rotaviruses in Chinese Bats: Genetic Composition, Serology, and Evidence for Bat-to-Human Transmission and Reassortment.

    Science.gov (United States)

    He, Biao; Huang, Xiaohong; Zhang, Fuqiang; Tan, Weilong; Matthijnssens, Jelle; Qin, Shaomin; Xu, Lin; Zhao, Zihan; Yang, Ling'en; Wang, Quanxi; Hu, Tingsong; Bao, Xiaolei; Wu, Jianmin; Tu, Changchun

    2017-06-15

    Bats are natural reservoirs for many pathogenic viruses, and increasing evidence supports the notion that bats can also harbor group A rotaviruses (RVAs), important causative agents of diarrhea in children and young animals. Currently, 8 RVA strains possessing completely novel genotype constellations or genotypes possibly originating from other mammals have been identified from African and Chinese bats. However, all the data were mainly based on detection of RVA RNA, present only during acute infections, which does not permit assessment of the true exposure of a bat population to RVA. To systematically investigate the genetic diversity of RVAs, 547 bat anal swabs or gut samples along with 448 bat sera were collected from five South Chinese provinces. Specific reverse transcription-PCR (RT-PCR) screening found four RVA strains. Strain GLRL1 possessed a completely novel genotype constellation, whereas the other three possessed a constellation consistent with the MSLH14-like genotype, a newly characterized group of viruses widely prevalent in Chinese insectivorous bats. Among the latter, strain LZHP2 provided strong evidence of cross-species transmission of RVAs from bats to humans, whereas strains YSSK5 and BSTM70 were likely reassortants between typical MSLH14-like RVAs and human RVAs. RVA-specific antibodies were detected in 10.7% (48/448) of bat sera by an indirect immunofluorescence assay (IIFA). Bats in Guangxi and Yunnan had a higher RVA-specific antibody prevalence than those from Fujian and Zhejiang provinces. These observations provide evidence for cross-species transmission of MSLH14-like bat RVAs to humans, highlighting the impact of bats as reservoirs of RVAs on public health. IMPORTANCE Bat viruses, such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), Ebola, Hendra, and Nipah viruses, are important pathogens causing outbreaks of severe emerging infectious diseases. However, little is known about bat viruses capable

  17. Human Genome Sequencing in Health and Disease

    Science.gov (United States)

    Gonzaga-Jauregui, Claudia; Lupski, James R.; Gibbs, Richard A.

    2013-01-01

    Following the “finished,” euchromatic, haploid human reference genome sequence, the rapid development of novel, faster, and cheaper sequencing technologies is making possible the era of personalized human genomics. Personal diploid human genome sequences have been generated, and each has contributed to our better understanding of variation in the human genome. We have consequently begun to appreciate the vastness of individual genetic variation from single nucleotide to structural variants. Translation of genome-scale variation into medically useful information is, however, in its infancy. This review summarizes the initial steps undertaken in clinical implementation of personal genome information, and describes the application of whole-genome and exome sequencing to identify the cause of genetic diseases and to suggest adjuvant therapies. Better analysis tools and a deeper understanding of the biology of our genome are necessary in order to decipher, interpret, and optimize clinical utility of what the variation in the human genome can teach us. Personal genome sequencing may eventually become an instrument of common medical practice, providing information that assists in the formulation of a differential diagnosis. We outline herein some of the remaining challenges. PMID:22248320

  18. Experimental oral transmission of chronic wasting disease to reindeer (Rangifer tarandus tarandus.

    Directory of Open Access Journals (Sweden)

    Gordon B Mitchell

    Full Text Available Chronic wasting disease (CWD, a transmissible spongiform encephalopathy of cervids, remains prevalent in North American elk, white-tailed deer and mule deer. A natural case of CWD in reindeer (Rangifer tarandus tarandus has not been reported despite potential habitat overlap with CWD-infected deer or elk herds. This study investigates the experimental transmission of CWD from elk or white-tailed deer to reindeer by the oral route of inoculation. Ante-mortem testing of the three reindeer exposed to CWD from white-tailed deer identified the accumulation of pathological PrP (PrP(CWD in the recto-anal mucosa associated lymphoid tissue (RAMALT of two reindeer at 13.4 months post-inoculation. Terminal CWD occurred in the two RAMALT-positive reindeer at 18.5 and 20 months post-inoculation while one other reindeer in the white-tailed deer CWD inoculum group and none of the 3 reindeer exposed to elk CWD developed disease. Tissue distribution analysis of PrP(CWD in CWD-affected reindeer revealed widespread deposition in central and peripheral nervous systems, lymphoreticular tissues, the gastrointestinal tract, neuroendocrine tissues and cardiac muscle. Analysis of prion protein gene (PRNP sequences in the 6 reindeer identified polymorphisms at residues 2 (V/M, 129 (G/S, 138 (S/N and 169 (V/M. These findings demonstrate that (i a sub-population of reindeer are susceptible to CWD by oral inoculation implicating the potential for transmission to other Rangifer species, and (ii certain reindeer PRNP polymorphisms may be protective against CWD infection.

  19. Potential risk of viral transmission from flying foxes to domestic animals and humans on the southern coast of West Java, Indonesia.

    Science.gov (United States)

    Basri, Chaerul; Arifin, Eko Muhammad Zainal; Takemae, Hitoshi; Hengjan, Yupadee; Iida, Keisuke; Sudarnika, Etih; Zahid, Abdul; Soejoedono, Retno Damayanti; Susetya, Heru; Sumiarto, Bambang; Kobayashi, Ryosuke; Agungpriyono, Srihadi; Hondo, Eiichi

    2017-09-29

    Flying foxes have been considered to be involved in the transmission of serious infectious diseases to humans. Using questionnaires, we aimed to determine the direct and/or indirect contacts of flying foxes in an Indonesian nature conservation area with domestic animals and humans living in the surrounding area. We surveyed 150 residents of 10 villages in West Java. Villages were classified into 3 groups: inside and/or within 1 km from the outer border of the conservation area and 1-5 km or 5-10 km away from the reserve's outer border. Data were collected by direct interview using a structured questionnaire consisting of the respondent characteristics (age, sex and occupation); histories of contacts between flying foxes and humans, dogs and other domestic animals; and knowledge about infectious diseases, mainly rabies, in flying foxes. We found that flying foxes from the nature conservation area often enter residential areas at night to look for food, especially during the fruit season. In these residential areas, flying foxes had direct contacts with humans and a few contacts with domestic animals, especially dogs. People who encounter flying foxes seldom used personal protective equipment, such as leather gloves, goggles and caps. The residents living around the conservation area mostly had poor knowledge about flying foxes and disease transmission. This situation shows that the population in this region is at a quite high risk for contracting infectious diseases from flying foxes.

  20. Models to capture the potential for disease transmission in domestic sheep flocks.

    Science.gov (United States)

    Schley, David; Whittle, Sophie; Taylor, Michael; Kiss, Istvan Zoltan

    2012-09-15

    Successful control of livestock diseases requires an understanding of how they spread amongst animals and between premises. Mathematical models can offer important insight into the dynamics of disease, especially when built upon experimental and/or field data. Here the dynamics of a range of epidemiological models are explored in order to determine which models perform best in capturing real-world heterogeneities at sufficient resolution. Individual based network models are considered together with one- and two-class compartmental models, for which the final epidemic size is calculated as a function of the probability of disease transmission occurring during a given physical contact between two individuals. For numerical results the special cases of a viral disease with a fast recovery rate (foot-and-mouth disease) and a bacterial disease with a slow recovery rate (brucellosis) amongst sheep are considered. Quantitative results from observational studies of physical contact amongst domestic sheep are applied and results from the differently structured flocks (ewes with newborn lambs, ewes with nearly weaned lambs and ewes only) compared. These indicate that the breeding cycle leads to significant changes in the expected basic reproduction ratio of diseases. The observed heterogeneity of contacts amongst animals is best captured by full network simulations, although simple compartmental models describe the key features of an outbreak but, as expected, often overestimate the speed of an outbreak. Here the weights of contacts are heterogeneous, with many low weight links. However, due to the well-connected nature of the networks, this has little effect and differences between models remain small. These results indicate that simple compartmental models can be a useful tool for modelling real-world flocks; their applicability will be greater still for more homogeneously mixed livestock, which could be promoted by higher intensity farming practices. Copyright © 2012

  1. Evaluation and Verification of Channel Transmission Characteristics of Human Body for Optimizing Data Transmission Rate in Electrostatic-Coupling Intra Body Communication System: A Comparative Analysis.

    Directory of Open Access Journals (Sweden)

    Yuhwai Tseng

    Full Text Available Intra-body communication is a new wireless scheme for transmitting signals through the human body. Understanding the transmission characteristics of the human body is therefore becoming increasingly important. Electrostatic-coupling intra-body communication system in a ground-free situation that integrate electronic products that are discretely located on individuals, such as mobile phones, PDAs, wearable computers, and biomedical sensors, are of particular interest.The human body is modeled as a simplified Resistor-Capacitor network. A virtual ground between the transmitter and receiver in the system is represented by a resister-capacitor network. Value of its resistance and capacitance are determined from a system perspective. The system is characterized by using a mathematical unit step function in digital baseband transmission scheme with and without Manchester code. As a result, the signal-to-noise and to-intersymbol-interference ratios are improved by manipulating the load resistor. The data transmission rate of the system is optimized. A battery-powered transmitter and receiver are developed to validate the proposal.A ground-free system fade signal energy especially for a low-frequency signal limited system transmission rate. The system transmission rate is maximized by simply manipulating the load resistor. Experimental results demonstrate that for a load resistance of 10k-50k Ω, the high-pass 3 dB frequency of the band-pass channel is 400kHz-2MHz in the worst-case scenario. The system allows a Manchester-coded baseband signal to be transmitted at speeds of up to 20M bit per second with signal-to-noise and signal-to-intersymbol-interference ratio of more than 10 dB.The human body can function as a high speed transmission medium with a data transmission rate of 20Mbps in an electrostatic-coupling intra-body communication system. Therefore, a wideband signal can be transmitted directly through the human body with a good signal

  2. Evaluation and Verification of Channel Transmission Characteristics of Human Body for Optimizing Data Transmission Rate in Electrostatic-Coupling Intra Body Communication System: A Comparative Analysis.

    Science.gov (United States)

    Tseng, Yuhwai; Su, Chauchin; Ho, Yingchieh

    2016-01-01

    Intra-body communication is a new wireless scheme for transmitting signals through the human body. Understanding the transmission characteristics of the human body is therefore becoming increasingly important. Electrostatic-coupling intra-body communication system in a ground-free situation that integrate electronic products that are discretely located on individuals, such as mobile phones, PDAs, wearable computers, and biomedical sensors, are of particular interest. The human body is modeled as a simplified Resistor-Capacitor network. A virtual ground between the transmitter and receiver in the system is represented by a resister-capacitor network. Value of its resistance and capacitance are determined from a system perspective. The system is characterized by using a mathematical unit step function in digital baseband transmission scheme with and without Manchester code. As a result, the signal-to-noise and to-intersymbol-interference ratios are improved by manipulating the load resistor. The data transmission rate of the system is optimized. A battery-powered transmitter and receiver are developed to validate the proposal. A ground-free system fade signal energy especially for a low-frequency signal limited system transmission rate. The system transmission rate is maximized by simply manipulating the load resistor. Experimental results demonstrate that for a load resistance of 10k-50k Ω, the high-pass 3 dB frequency of the band-pass channel is 400kHz-2MHz in the worst-case scenario. The system allows a Manchester-coded baseband signal to be transmitted at speeds of up to 20M bit per second with signal-to-noise and signal-to-intersymbol-interference ratio of more than 10 dB. The human body can function as a high speed transmission medium with a data transmission rate of 20Mbps in an electrostatic-coupling intra-body communication system. Therefore, a wideband signal can be transmitted directly through the human body with a good signal-to-noise quality of 10 dB if

  3. Truncation artifact suppression in cone-beam radionuclide transmission CT using maximum likelihood techniques: evaluation with human subjects

    International Nuclear Information System (INIS)

    Manglos, S.H.

    1992-01-01

    Transverse image truncation can be a serious problem for human imaging using cone-beam transmission CT (CB-CT) implemented on a conventional rotating gamma camera. This paper presents a reconstruction method to reduce or eliminate the artifacts resulting from the truncation. The method uses a previously published transmission maximum likelihood EM algorithm, adapted to the cone-beam geometry. The reconstruction method is evaluated qualitatively using three human subjects of various dimensions and various degrees of truncation. (author)

  4. Human Leptospirosis Infection in Fiji: An Eco-epidemiological Approach to Identifying Risk Factors and Environmental Drivers for Transmission.

    Science.gov (United States)

    Lau, Colleen L; Watson, Conall H; Lowry, John H; David, Michael C; Craig, Scott B; Wynwood, Sarah J; Kama, Mike; Nilles, Eric J

    2016-01-01

    Leptospirosis is an important zoonotic disease in the Pacific Islands. In Fiji, two successive cyclones and severe flooding in 2012 resulted in outbreaks with 576 reported cases and 7% case-fatality. We conducted a cross-sectional seroprevalence study and used an eco-epidemiological approach to characterize risk factors and drivers for human leptospirosis infection in Fiji, and aimed to provide an evidence base for improving the effectiveness of public health mitigation and intervention strategies. Antibodies indicative of previous or recent infection were found in 19.4% of 2152 participants (81 communities on the 3 main islands). Questionnaires and geographic information systems data were used to assess variables related to demographics, individual behaviour, contact with animals, socioeconomics, living conditions, land use, and the natural environment. On multivariable logistic regression analysis, variables associated with the presence of Leptospira antibodies included male gender (OR 1.55), iTaukei ethnicity (OR 3.51), living in villages (OR 1.64), lack of treated water at home (OR 1.52), working outdoors (1.64), living in rural areas (OR 1.43), high poverty rate (OR 1.74), living Fiji are complex and multifactorial, with environmental factors playing crucial roles. With global climate change, severe weather events and flooding are expected to intensify in the South Pacific. Population growth could also lead to more intensive livestock farming; and urbanization in developing countries is often associated with urban and peri-urban slums where diseases of poverty proliferate. Climate change, flooding, population growth, urbanization, poverty and agricultural intensification are important drivers of zoonotic disease transmission; these factors may independently, or potentially synergistically, lead to enhanced leptospirosis transmission in Fiji and other similar settings.

  5. Finding aroma clues in the human breath to diagnose diseases

    Science.gov (United States)

    A. Dan Wilson

    2016-01-01

    History of human odor analysis in disease diagnosis The use of the sense of smell as an indicator of human disease probably originated with Hippocrates (circa 400 BC). Early medical practitioners recognized that the presence of human diseases changed the odors released from the body and breath. Physicians once relied heavily on their sense of smell to provide useful...

  6. Mitochondrial Fusion Proteins and Human Diseases

    Directory of Open Access Journals (Sweden)

    Michela Ranieri

    2013-01-01

    Full Text Available Mitochondria are highly dynamic, complex organelles that continuously alter their shape, ranging between two opposite processes, fission and fusion, in response to several stimuli and the metabolic demands of the cell. Alterations in mitochondrial dynamics due to mutations in proteins involved in the fusion-fission machinery represent an important pathogenic mechanism of human diseases. The most relevant proteins involved in the mitochondrial fusion process are three GTPase dynamin-like proteins: mitofusin 1 (MFN1 and 2 (MFN2, located in the outer mitochondrial membrane, and optic atrophy protein 1 (OPA1, in the inner membrane. An expanding number of degenerative disorders are associated with mutations in the genes encoding MFN2 and OPA1, including Charcot-Marie-Tooth disease type 2A and autosomal dominant optic atrophy. While these disorders can still be considered rare, defective mitochondrial dynamics seem to play a significant role in the molecular and cellular pathogenesis of more common neurodegenerative diseases, for example, Alzheimer’s and Parkinson’s diseases. This review provides an overview of the basic molecular mechanisms involved in mitochondrial fusion and focuses on the alteration in mitochondrial DNA amount resulting from impairment of mitochondrial dynamics. We also review the literature describing the main disorders associated with the disruption of mitochondrial fusion.

  7. Human prion diseases in the United States.

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    Robert C Holman

    Full Text Available BACKGROUND: Prion diseases are a family of rare, progressive, neurodegenerative disorders that affect humans and animals. The most common form of human prion disease, Creutzfeldt-Jakob disease (CJD, occurs worldwide. Variant CJD (vCJD, a recently emerged human prion disease, is a zoonotic foodborne disorder that occurs almost exclusively in countries with outbreaks of bovine spongiform encephalopathy. This study describes the occurrence and epidemiology of CJD and vCJD in the United States. METHODOLOGY/PRINCIPAL FINDINGS: Analysis of CJD and vCJD deaths using death certificates of US residents for 1979-2006, and those identified through other surveillance mechanisms during 1996-2008. Since CJD is invariably fatal and illness duration is usually less than one year, the CJD incidence is estimated as the death rate. During 1979 through 2006, an estimated 6,917 deaths with CJD as a cause of death were reported in the United States, an annual average of approximately 247 deaths (range 172-304 deaths. The average annual age-adjusted incidence for CJD was 0.97 per 1,000,000 persons. Most (61.8% of the CJD deaths occurred among persons >or=65 years of age for an average annual incidence of 4.8 per 1,000,000 persons in this population. Most deaths were among whites (94.6%; the age-adjusted incidence for whites was 2.7 times higher than that for blacks (1.04 and 0.40, respectively. Three patients who died since 2004 were reported with vCJD; epidemiologic evidence indicated that their infection was acquired outside of the United States. CONCLUSION/SIGNIFICANCE: Surveillance continues to show an annual CJD incidence rate of about 1 case per 1,000,000 persons and marked differences in CJD rates by age and race in the United States. Ongoing surveillance remains important for monitoring the stability of the CJD incidence rates, and detecting occurrences of vCJD and possibly other novel prion diseases in the United States.

  8. Common raven occurrence in relation to energy transmission line corridors transiting human-altered sagebrush steppe

    Science.gov (United States)

    Coates, Peter S.; Howe, Kristy B.; Casazza, Michael L.; Delehanty, David J.

    2014-01-01

    Energy-related infrastructure and other human enterprises within sagebrush steppe of the American West often results in changes that promote common raven (Corvus corax; hereafter, raven) populations. Ravens, a generalist predator capable of behavioral innovation, present a threat to many species of conservation concern. We evaluate the effects of detailed features of an altered landscape on the probability of raven occurrence using extensive raven survey (n= 1045) and mapping data from southern Idaho, USA. We found nonlinear relationships between raven occurrence and distances to transmission lines, roads, and facilities. Most importantly, raven occurrence was greater with presence of transmission lines up to 2.2 km from the corridor.We further explain variation in raven occurrence along anthropogenic features based on the amount of non-native vegetation and cover type edge, such that ravens select fragmented sagebrush stands with patchy, exotic vegetative introgression. Raven occurrence also increased with greater length of edge formed by the contact of big sagebrush (Artemisia tridentate spp.) with non-native vegetation cover types. In consideration of increasing alteration of sagebrush steppe, these findings will be useful for planning energy transmission corridor placement and other management activities where conservation of sagebrush obligate species is a priority.

  9. Evolving building blocks of rhythm: how human cognition creates music via cultural transmission.

    Science.gov (United States)

    Ravignani, Andrea; Thompson, Bill; Grossi, Thomas; Delgado, Tania; Kirby, Simon

    2018-03-06

    Why does musical rhythm have the structure it does? Musical rhythm, in all its cross-cultural diversity, exhibits commonalities across world cultures. Traditionally, music research has been split into two fields. Some scientists focused on musicality, namely the human biocognitive predispositions for music, with an emphasis on cross-cultural similarities. Other scholars investigated music, seen as a cultural product, focusing on the variation in world musical cultures. Recent experiments found deep connections between music and musicality, reconciling these opposing views. Here, we address the question of how individual cognitive biases affect the process of cultural evolution of music. Data from two experiments are analyzed using two complementary techniques. In the experiments, participants hear drumming patterns and imitate them. These patterns are then given to the same or another participant to imitate. The structure of these initially random patterns is tracked along experimental "generations." Frequentist statistics show how participants' biases are amplified by cultural transmission, making drumming patterns more structured. Structure is achieved faster in transmission within rather than between participants. A Bayesian model approximates the motif structures participants learned and created. Our data and models suggest that individual biases for musicality may shape the cultural transmission of musical rhythm. © 2018 New York Academy of Sciences.

  10. Foot-and-mouth disease virus : the role of infection routes and species differences in the transmission of FMDV

    NARCIS (Netherlands)

    Bravo De Rueda Cabrera, C.

    2015-01-01

    ÁFoot-and-mouth disease is a contagious viral disease of cloven-hoofed animals (e.g. cattle, sheep, pigs) and can cause severe economic losses to the farm animal industries. The aim of this thesis was to quantify underlying mechanisms regarding transmission of FMDV. With data from past animal

  11. DNA multigene characterization of Fasciola hepatica and Lymnaea neotropica and its fascioliasis transmission capacity in Uruguay, with historical correlation, human report review and infection risk analysis.

    Science.gov (United States)

    Bargues, María Dolores; Gayo, Valeria; Sanchis, Jaime; Artigas, Patricio; Khoubbane, Messaoud; Birriel, Soledad; Mas-Coma, Santiago

    2017-02-01

    Fascioliasis is a pathogenic disease transmitted by lymnaeid snails and recently emerging in humans, in part due to effects of climate changes, anthropogenic environment modifications, import/export and movements of livestock. South America is the continent presenting more human fascioliasis hyperendemic areas and the highest prevalences and intensities known. These scenarios appear mainly linked to altitude areas in Andean countries, whereas lowland areas of non-Andean countries, such as Uruguay, only show sporadic human cases or outbreaks. A study including DNA marker sequencing of fasciolids and lymnaeids, an experimental study of the life cycle in Uruguay, and a review of human fascioliasis in Uruguay, are performed. The characterization of Fasciola hepatica from cattle and horses of Uruguay included the complete sequences of the ribosomal DNA ITS-2 and ITS-1 and mitochondrial DNA cox1 and nad1. ITS-2, ITS-1, partial cox1 and rDNA 16S gene of mtDNA were used for lymnaeids. Results indicated that vectors belong to Lymnaea neotropica instead of to Lymnaea viator, as always reported from Uruguay. The life cycle and transmission features of F. hepatica by L. neotropica of Uruguay were studied under standardized experimental conditions to enable a comparison with the transmission capacity of F. hepatica by Galba truncatula at very high altitude in Bolivia. On this baseline, we reviewed the 95 human fascioliasis cases reported in Uruguay and analyzed the risk of human infection in front of future climate change estimations. The correlation of fasciolid and lymnaeid haplotypes with historical data on the introduction and spread of livestock into Uruguay allowed to understand the molecular diversity detected. Although Uruguayan L. neotropica is a highly efficient vector, its transmission capacity is markedly lower than that of Bolivian G. truncatula. This allows to understand the transmission and epidemiological differences between Andean highlands and non

  12. Compassionate Love as a Predictor of Reduced HIV Disease Progression and Transmission Risk

    Directory of Open Access Journals (Sweden)

    Heidemarie Kremer

    2013-01-01

    Full Text Available Objectives. This study examined if compassionate love (CL predicts HIV disease progression and transmission risk. Scientific study of CL emerged with Underwood’s working model of other-centered CL, defining five criteria: free choice, cognitive understanding, valuing/empowering, openness/receptivity for spirituality, and response of the heart. Method. This 10-year cohort study collected 6-monthly interviews/essays on coping with HIV and trauma of 177 people with HIV in South Florida. Secondary qualitative content analysis on other-centered CL inductively added the component of CL towards self. Deductively, we coded the presence of the five criteria of CL and rated the benefit of CL for the recipient on a 6-point Likert scale. Growth-curve modeling (reduced to 4 years due to cohort effects investigated if CL predicts CD4 slope (HIV disease progression and cumulative viral load detection (transmission risk. Results. Valuing/empowering and cognitive understanding were the essential criteria for CL to confer long-term benefits. CL had a higher benefit for recipients if given out of free choice. High scores of CL towards self were reciprocal with receiving (93% and giving (77% other-centered CL. Conversely, those rated low on CL towards self were least likely to score high on receiving (38% and giving (49% other-centered CL. Growth-curve modeling showed that CL towards self predicted 4-year cumulative undetectable viral load (independent from sociocultural differences, substance use disorder, baseline CD4 and viral load. Those high versus low on CL self were 2.25 times more likely to have undetectable viral load at baseline and 1.49 times more likely to maintain undetectable viral load over time. CL towards self predicted CD4 preservation after controlling for differences in CL giving. Conclusions. CL towards self is potentially the seed of being expressive and receptive of CL. Health care professionals prepared to walk the extra mile for those who

  13. Inherited prion disease A117V is not simply a proteinopathy but produces prions transmissible to transgenic mice expressing homologous prion protein.

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    Emmanuel A Asante

    Full Text Available Prions are infectious agents causing fatal neurodegenerative diseases of humans and animals. In humans, these have sporadic, acquired and inherited aetiologies. The inherited prion diseases are caused by one of over 30 coding mutations in the human prion protein (PrP gene (PRNP and many of these generate infectious prions as evidenced by their experimental transmissibility by inoculation to laboratory animals. However, some, and in particular an extensively studied type of Gerstmann-Sträussler-Scheinker syndrome (GSS caused by a PRNP A117V mutation, are thought not to generate infectious prions and instead constitute prion proteinopathies with a quite distinct pathogenetic mechanism. Multiple attempts to transmit A117V GSS have been unsuccessful and typical protease-resistant PrP (PrP(Sc, pathognomonic of prion disease, is not detected in brain. Pathogenesis is instead attributed to production of an aberrant topological form of PrP, C-terminal transmembrane PrP ((CtmPrP. Barriers to transmission of prion strains from one species to another appear to relate to structural compatibility of PrP in host and inoculum and we have therefore produced transgenic mice expressing human 117V PrP. We found that brain tissue from GSS A117V patients did transmit disease to these mice and both the neuropathological features of prion disease and presence of PrP(Sc was demonstrated in the brains of recipient transgenic mice. This PrP(Sc rapidly degraded during laboratory analysis, suggesting that the difficulty in its detection in patients with GSS A117V could relate to post-mortem proteolysis. We conclude that GSS A117V is indeed a prion disease although the relative contributions of (CtmPrP and prion propagation in neurodegeneration and their pathogenetic interaction remains to be established.

  14. Inherited prion disease A117V is not simply a proteinopathy but produces prions transmissible to transgenic mice expressing homologous prion protein.

    Science.gov (United States)

    Asante, Emmanuel A; Linehan, Jacqueline M; Smidak, Michelle; Tomlinson, Andrew; Grimshaw, Andrew; Jeelani, Asif; Jakubcova, Tatiana; Hamdan, Shyma; Powell, Caroline; Brandner, Sebastian; Wadsworth, Jonathan D F; Collinge, John

    2013-01-01

    Prions are infectious agents causing fatal neurodegenerative diseases of humans and animals. In humans, these have sporadic, acquired and inherited aetiologies. The inherited prion diseases are caused by one of over 30 coding mutations in the human prion protein (PrP) gene (PRNP) and many of these generate infectious prions as evidenced by their experimental transmissibility by inoculation to laboratory animals. However, some, and in particular an extensively studied type of Gerstmann-Sträussler-Scheinker syndrome (GSS) caused by a PRNP A117V mutation, are thought not to generate infectious prions and instead constitute prion proteinopathies with a quite distinct pathogenetic mechanism. Multiple attempts to transmit A117V GSS have been unsuccessful and typical protease-resistant PrP (PrP(Sc)), pathognomonic of prion disease, is not detected in brain. Pathogenesis is instead attributed to production of an aberrant topological form of PrP, C-terminal transmembrane PrP ((Ctm)PrP). Barriers to transmission of prion strains from one species to another appear to relate to structural compatibility of PrP in host and inoculum and we have therefore produced transgenic mice expressing human 117V PrP. We found that brain tissue from GSS A117V patients did transmit disease to these mice and both the neuropathological features of prion disease and presence of PrP(Sc) was demonstrated in the brains of recipient transgenic mice. This PrP(Sc) rapidly degraded during laboratory analysis, suggesting that the difficulty in its detection in patients with GSS A117V could relate to post-mortem proteolysis. We conclude that GSS A117V is indeed a prion disease although the relative contributions of (Ctm)PrP and prion propagation in neurodegeneration and their pathogenetic interaction remains to be established.

  15. The role of pars flaccida in human middle ear sound transmission.

    Science.gov (United States)

    Aritomo, H; Goode, R L; Gonzalez, J

    1988-04-01

    The role of the pars flaccida in middle ear sound transmission was studied with the use of twelve otoscopically normal, fresh, human temporal bones. Peak-to-peak umbo displacement in response to a constant sound pressure level at the tympanic membrane was measured with a noncontacting video measuring system capable of repeatable measurements down to 0.2 micron. Measurements were made before and after pars flaccida modifications at 18 frequencies between 100 and 4000 Hz. Four pars flaccida modifications were studied: (1) acoustic insulation of the pars flaccida to the ear canal with a silicone rubber baffle, (2) stiffening the pars flaccida with cyanoacrylate cement, (3) decreasing the tension of the pars flaccida with a nonperforating incision, and (4) perforation of the pars flaccida. All of the modifications (except the perforation) had a minimal effect on umbo displacement; this seems to imply that the pars flaccida has a minor acoustic role in human beings.

  16. Oregon ESA 2010 BKD vertical transmission - Test of analyses for bacterial kidney disease as predictors of vertical transmission

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Although the pathogen causing bacterial kidney disease is known to be transmitted from broodstock female to offspring, there is large uncertainty around the...

  17. Epidemiology of transmissible diseases: Array hybridization and next generation sequencing as universal nucleic acid-mediated typing tools.

    Science.gov (United States)

    Michael Dunne, W; Pouseele, Hannes; Monecke, Stefan; Ehricht, Ralf; van Belkum, Alex

    2017-09-21

    The magnitude of interest in the epidemiology of transmissible human diseases is reflected in the vast number of tools and methods developed recently with the expressed purpose to characterize and track evolutionary changes that occur in agents of these diseases over time. Within the past decade a new suite of such tools has become available with the emergence of the so-called "omics" technologies. Among these, two are exponents of the ongoing genomic revolution. Firstly, high-density nucleic acid probe arrays have been proposed and developed using various chemical and physical approaches. Via hybridization-mediated detection of entire genes or genetic polymorphisms in such genes and intergenic regions these so called "DNA chips" have been successfully applied for distinguishing very closely related microbial species and strains. Second and even more phenomenal, next generation sequencing (NGS) has facilitated the assessment of the complete nucleotide sequence of entire microbial genomes. This technology currently provides the most detailed level of bacterial genotyping and hence allows for the resolution of microbial spread and short-term evolution in minute detail. We will here review the very recent history of these two technologies, sketch their usefulness in the elucidation of the spread and epidemiology of mostly hospital-acquired infections and discuss future developments. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. New variant of Creutzfeldt-Jakob (vCJD disease and other human prion diseases under epidemiological surveillance in Brazil

    Directory of Open Access Journals (Sweden)

    Vera Lúcia Gattás

    Full Text Available Abstract To increase the timeliness of detection of human cases of the new variant of Creutzfeldt-Jakob disease (vCJD and to reduce the risk of transmission, the Brazilian Ministry of Health has established and standardized rules and control measures. These include the definition of criteria for suspect cases, reporting, monitoring, and control measures for illness prevention and transmission. Guidelines to be used by the team of health care staff were published and distributed to health workers. A detailed proposal for a simplified system of surveillance for prion diseases was developed and mandatory reporting introduced. Additional effort is necessary to increase vCJD case detection, thus making it necessary to establish a partnership with health care services for best identification of suspected cases and dissemination of information to all involved in the service dealing with vCJD investigation.

  19. A survey of the transmission of infectious diseases/infections between wild and domestic ungulates in Europe

    Science.gov (United States)

    2011-01-01

    The domestic animals/wildlife interface is becoming a global issue of growing interest. However, despite studies on wildlife diseases being in expansion, the epidemiological role of wild animals in the transmission of infectious diseases remains unclear most of the time. Multiple diseases affecting livestock have already been identified in wildlife, especially in wild ungulates. The first objective of this paper was to establish a list of infections already reported in European wild ungulates. For each disease/infection, three additional materials develop examples already published, specifying the epidemiological role of the species as assigned by the authors. Furthermore, risk factors associated with interactions between wild and domestic animals and regarding emerging infectious diseases are summarized. Finally, the wildlife surveillance measures implemented in different European countries are presented. New research areas are proposed in order to provide efficient tools to prevent the transmission of diseases between wild ungulates and livestock. PMID:21635726

  20. The current screening programme for congenital transmission of Chagas disease in Catalonia, Spain.

    Science.gov (United States)

    Basile, L; Oliveira, I; Ciruela, P; Plasencia, A

    2011-09-22

    Due to considerable numbers of migrants from Chagas disease-endemic countries living in Catalonia, the Catalonian Health Department has recently implemented a screening programme for preventing congenital transmission, targeting Latin American pregnant women who attend antenatal consultations. Diagnosis of Trypanosoma cruzi infection in women is based on two positive serological tests. Screening of newborns from mothers with positive serology is based on a parasitological test during the first 48 hours of life and/or conventional serological analysis at the age of nine months. If either of these tests is positive, treatment with benznidazole is started following the World Health Organization's recommendations. The epidemiological surveillance of the programme is based on the Microbiological Reporting System of Catalonia, a well established network of laboratories. Once a positive case is reported, the responsible physician is asked to complete a structured epidemiological questionnaire. Clinical and demographic data are registered in the Voluntary Case Registry of Chagas Disease, a database administered by the Catalonian Health Department. It is expected that this programme will improve the understanding of the real burden of Chagas disease in the region. Furthermore, this initiative could encourage the implementation of similar programmes in other regions of Spain and even in other European countries.

  1. Pathogens and diseases of freshwater mussels in the United States: Studies on bacterial transmission and depuration

    Science.gov (United States)

    Starliper, Clifford E.; Cipriano, R.C.; Bruckner, A.W.; Shchelkunov, I.S.

    2011-01-01

    Unionid mussels are recognized as important contributors to healthy aquatic ecosystems, as well as bioindicators of environmental perturbations. Because they are sedentary, filter feeding animals and require hosts (i.e., fishes) to transform embryonic glochidia, mussels are susceptible to direct adverse environmental parameters, and indirect parameters that restrict the timely presence of the host(s). Their numbers have declined in recent decades to a point that this fauna is regarded as one of the most imperiled in North America. The most significant threat to populations of native unionids in recent years has been the introduction and spread of zebra mussels Dreissena polymorpha. Many federal and state agencies, and private interests are now engaged in mussel conservation efforts, including collecting selected imperiled species from impacted rivers and lakes and propagating them at refuges for future population augmentations. One essential consideration with mussel propagation and their intensive culture at refugia is the prevention of pathogen introductions and control of diseases. Currently, there are few reports of etiological agents causing diseases among freshwater mussels; however, because of increased observations of mussel die-offs in conjunction with transfers of live animals between natural waters and refugia, disease problems can be anticipated to emerge. This review summarizes research to develop bacterial isolation techniques, study pathogen transmission between fish and mussels, identify causes of seasonal mussel die-offs, and develop non-destructive methods for pathogen detection. These efforts were done to develop disease preventative techniques for use by resource managers to avoid potential large-scale disease problems in restoration and population augmentation efforts among imperiled populations.

  2. [Possible oral transmission of Chagas disease among hydrocarbons sector workers in Casanare, Colombia, 2014].

    Science.gov (United States)

    Zuleta-Dueñas, Liliana Patricia; López-Quiroga, Ángela Johana; Torres-Torres, Fernando; Castañeda-Porras, Oneida

    2017-06-01

    Trypanosoma cruzi, the etiological agent for Chagas disease, can be transmitted by oral intake of contaminated food or drinks. During epidemiological week 14 of 2014, two cases of acute Chagas disease were notified among hydrocarbons sector workers in Paz de Ariporo, Casanare. To characterize the affected population, to establish control and prevention measures and to confirm the outbreak. We conducted an outbreak investigation that included the following components: a) Search for symptomatic people compatible with Chagas disease according to the case definition for their referral to medical services; b) entomological survey (192/197 houses); c) sanitary inspection and microbiological analysis of food samples; and d) study of reservoirs. Data management and analysis were done with Epi-Info 7.1.5 using descriptive statistics. We also calculated intradomicile and peridomicile triatomine infestation indexes. We detected 552 exposed people; 40 had the disease (7.2%), of whom seven were women (17,5%) and 33, men (82.5%), i.e., a male-female ratio of 5:1. The mean age was 39.1 ± 10.8 years; the attack rate was 7.2% and lethality, 5% (2/40). Symptoms included fever (100% of cases), headache (80%), myalgia and arthralgia (65%), facial edema (55%), and abdominal pain (37.5%). The mean incubation time was 17 days (range: 3-21). Rhodnius prolixus domiciliary infestation index was 3.3 % and 2.2% in the peridomicile. In the five restaurants inspected sanitary conditions were deficient and food samples were microbiologically non-conforming. We found a dog and two opossums positive for IgG antibodies by ELISA. Environmental, sanitary and epidemiological conditions at the place confirmed an outbreak of Chagas diseases related to occupational exposure, possibly by oral transmission, which may be the largest to date in Colombia.

  3. Preventing Airborne Disease Transmission: Review of Methods for Ventilation Design in Health Care Facilities

    Science.gov (United States)

    Aliabadi, Amir A.; Rogak, Steven N.; Bartlett, Karen H.; Green, Sheldon I.

    2011-01-01

    Health care facility ventilation design greatly affects disease transmission by aerosols. The desire to control infection in hospitals and at the same time to reduce their carbon footprint motivates the use of unconventional solutions for building design and associated control measures. This paper considers indoor sources and types of infectious aerosols, and pathogen viability and infectivity behaviors in response to environmental conditions. Aerosol dispersion, heat and mass transfer, deposition in the respiratory tract, and infection mechanisms are discussed, with an emphasis on experimental and modeling approaches. Key building design parameters are described that include types of ventilation systems (mixing, displacement, natural and hybrid), air exchange rate, temperature and relative humidity, air flow distribution structure, occupancy, engineered disinfection of air (filtration and UV radiation), and architectural programming (source and activity management) for health care facilities. The paper describes major findings and suggests future research needs in methods for ventilation design of health care facilities to prevent airborne infection risk. PMID:22162813

  4. Dose-response relationships for environmentally mediated infectious disease transmission models.

    Directory of Open Access Journals (Sweden)

    Andrew F Brouwer

    2017-04-01

    Full Text Available Environmentally mediated infectious disease transmission models provide a mechanistic approach to examining environmental interventions for outbreaks, such as water treatment or surface decontamination. The shift from the classical SIR framework to one incorporating the environment requires codifying the relationship between exposure to environmental pathogens and infection, i.e. the dose-response relationship. Much of the work characterizing the functional forms of dose-response relationships has used statistical fit to experimental data. However, there has been little research examining the consequences of the choice of functional form in the context of transmission dynamics. To this end, we identify four properties of dose-response functions that should be considered when selecting a functional form: low-dose linearity, scalability, concavity, and whether it is a single-hit model. We find that i middle- and high-dose data do not constrain the low-dose response, and different dose-response forms that are equally plausible given the data can lead to significant differences in simulated outbreak dynamics; ii the choice of how to aggregate continuous exposure into discrete doses can impact the modeled force of infection; iii low-dose linear, concave functions allow the basic reproduction number to control global dynamics; and iv identifiability analysis offers a way to manage multiple sources of uncertainty and leverage environmental monitoring to make inference about infectivity. By applying an environmentally mediated infectious disease model to the 1993 Milwaukee Cryptosporidium outbreak, we demonstrate that environmental monitoring allows for inference regarding the infectivity of the pathogen and thus improves our ability to identify outbreak characteristics such as pathogen strain.

  5. Foot-and-mouth Disease Transmission in Africa: Implications for Control, a Review.

    Science.gov (United States)

    Tekleghiorghis, T; Moormann, R J M; Weerdmeester, K; Dekker, A

    2016-04-01

    In Africa, for the control of foot-and-mouth disease (FMD), more information is needed on the spread of the disease at local, regional and inter-regional level. The aim of this review is to identify the role that animal husbandry, trade and wildlife have on the transmission of FMD and to provide a scientific basis for different FMD control measures in Africa. Review of literature, published reports and databases shows that there is more long distance spread of FMD virus serotypes within North, West, Central and East Africa than in southern Africa. In North, West, Central and East Africa migratory animal husbandry systems often related with search for grazing and water as well as trade are practiced to a greater extent than in southern Africa. In southern Africa, the role of African buffalo (Syncerus caffer) is more extensively studied than in the other parts of Africa, but based on the densities of African buffalo in Central and East Africa, one would assume that buffalo should also play a role in the epidemiology of FMD in this part of Africa. More sampling of buffalo is necessary in West, Central and East Africa. The genetic analysis of virus strains has proven to be valuable to increase our understanding in the spread of FMD in Africa. This review shows that there is a difference in FMD occurrence between southern Africa and the rest of the continent; this distinction is most likely based on differences in animal husbandry and trade systems. Insufficient data on FMD in wildlife outside southern Africa is limiting our understanding on the role wildlife plays in the transmission of FMD in the other buffalo inhabited areas of Africa. © 2014 Blackwell Verlag GmbH.

  6. Unifying Viral Genetics and Human Transportation Data to Predict the Global Transmission Dynamics of Human Influenza H3N2

    NARCIS (Netherlands)

    P. Lemey (Philippe); A. Rambaut (Andrew); T. Bedford (Trevor); R. Faria (Rui); F. Bielejec (Filip); G. Baele (Guy); C.A. Russell (Colin); D.J. Smith (Derek James); O. Pybus (Oliver); K. Brockmann; M.A. Suchard (Marc)

    2014-01-01

    textabstractInformation on global human movement patterns is central to spatial epidemiological models used to predict the behavior of influenza and other infectious diseases. Yet it remains difficult to test which modes of dispersal drive pathogen spread at various geographic scales using standard

  7. Simian virus 40 infection in humans and association with human diseases: results and hypotheses

    International Nuclear Information System (INIS)

    Barbanti-Brodano, Giuseppe; Sabbioni, Silvia; Martini, Fernanda; Negrini, Massimo; Corallini, Alfredo; Tognon, Mauro

    2004-01-01

    Simian virus 40 (SV40) is a monkey virus that was introduced in the human population by contaminated poliovaccines, produced in SV40-infected monkey cells, between 1955 and 1963. Epidemiological evidence now suggests that SV40 may be contagiously transmitted in humans by horizontal infection, independent of the earlier administration of SV40-contaminated poliovaccines. This evidence includes detection of SV40 DNA sequences in human tissues and of SV40 antibodies in human sera, as well as rescue of infectious SV40 from a human tumor. Detection of SV40 DNA sequences in blood and sperm and of SV40 virions in sewage points to the hematic, sexual, and orofecal routes as means of virus transmission in humans. The site of latent infection in humans is not known, but the presence of SV40 in urine suggests the kidney as a possible site of latency, as it occurs in the natural monkey host. SV40 in humans is associated with inflammatory kidney diseases and with specific tumor types: mesothelioma, lymphoma, brain, and bone. These human tumors correspond to the neoplasms that are induced by SV40 experimental inoculation in rodents and by generation of transgenic mice with the SV40 early region gene directed by its own early promoter-enhancer. The mechanisms of SV40 tumorigenesis in humans are related to the properties of the two viral oncoproteins, the large T antigen (Tag) and the small t antigen (tag). Tag acts mainly by blocking the functions of p53 and RB tumor suppressor proteins, as well as by inducing chromosomal aberrations in the host cell. These chromosome alterations may hit genes important in oncogenesis and generate genetic instability in tumor cells. The clastogenic activity of Tag, which fixes the chromosome damage in the infected cells, may explain the low viral load in SV40-positive human tumors and the observation that Tag is expressed only in a fraction of tumor cells. 'Hit and run' seems the most plausible mechanism to support this situation. The small tag

  8. Familial transmission of chronic obstructive pulmonary disease in adoptees: a Swedish nationwide family study.

    Science.gov (United States)

    Zöller, Bengt; Li, Xinjun; Sundquist, Jan; Sundquist, Kristina

    2015-04-13

    Familial clustering of chronic obstructive pulmonary disease (COPD) is well established, but the familial risk of COPD has not been determined among adoptees. The aim was to determine whether the familial transmission of COPD is related to disease in biological and/or adoptive parents. Historic cohort study. 80,214 (50% females). The Swedish Multi-Generation Register was used to follow all Swedish-born adoptees born in 1932-2004 (n=80,214) between 1 January 1964 and 31 December 2010 for COPD (n=1978). The risk of COPD was estimated in adoptees with at least one biological parent with COPD but no adoptive parent with COPD (n=162) compared with adoptees without a biological or adoptive parent with COPD. The risk of COPD was also determined in adoptees with at least one adoptive parent but no biological parent with COPD (n=110), and in adoptees with both affected biological and adoptive parents (n=162). COPD in adoptees. Adoptees with COPD in at least one biological parent but no adoptive parent were more likely to have COPD than adoptees without a biological or adoptive parent with COPD (standardised incidence ratio, SIR=1.98 (95% CI 1.69 to 2.31)). The familial SIR for adoptees with both a biological parent and an adoptive parent with COPD was 1.68 (95% CI 1.39 to 2.00). Adoptees with at least one adoptive parent with COPD but no biological parent with COPD were not at an increased risk of COPD (SIR=1.12 (95% CI 0.92 to 1.35)). The findings of the study show that the familial transmission of COPD is associated with COPD in biological but not adoptive parents, suggesting that genetic or early life factors are important in the familial transmission of COPD. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  9. Distantiae transmission of Trypanosoma cruzi: a new epidemiological feature of acute Chagas disease in Brazil.

    Directory of Open Access Journals (Sweden)

    Samanta Cristina das Chagas Xavier

    2014-05-01

    Full Text Available BACKGROUND: The new epidemiological scenario of orally transmitted Chagas disease that has emerged in Brazil, and mainly in the Amazon region, needs to be addressed with a new and systematic focus. Belém, the capital of Pará state, reports the highest number of acute Chagas disease (ACD cases associated with the consumption of açaí juice. METHODOLOGY/PRINCIPAL FINDINGS: The wild and domestic enzootic transmission cycles of Trypanosoma cruzi were evaluated in the two locations (Jurunas and Val-de Cães that report the majority of the autochthonous cases of ACD in Belém city. Moreover, we evaluated the enzootic cycle on the three islands that provide most of the açaí fruit that is consumed in these localities. We employed parasitological and serological tests throughout to evaluate infectivity competence and exposure to T. cruzi. In Val-de-Cães, no wild mammal presented positive parasitological tests, and 56% seroprevalence was observed, with low serological titers. Three of 14 triatomines were found to be infected (TcI. This unexpected epidemiological picture does not explain the high number of autochthonous ACD cases. In Jurunas, the cases of ACD could not be autochthonous because of the absence of any enzootic cycle of T. cruzi. In contrast, in the 3 island areas from which the açaí fruit originates, 66.7% of wild mammals and two dogs displayed positive hemocultures, and 15.6% of triatomines were found to be infected by T. cruzi. Genotyping by mini-exon gene and PCR-RFLP (1f8/Akw21I targeting revealed that the mammals and triatomines from the islands harbored TcI and Trypanosoma rangeli in single and mixed infections. CONCLUSION/SIGNIFICANCE: These findings show that cases of Chagas disease in the urban area of Belém may be derived from infected triatomines coming together with the açaí fruits from distant islands. We term this new epidemiological feature of Chagas disease as "Distantiae transmission".

  10. Human Islet Amyloid Polypeptide Fibril Binding to Catalase: A Transmission Electron Microscopy and Microplate Study

    Directory of Open Access Journals (Sweden)

    Nathaniel G. N. Milton

    2010-01-01

    Full Text Available The diabetes-associated human islet amyloid polypeptide (IAPP is a 37-amino-acid peptide that forms fibrils in vitro and in vivo. Human IAPP fibrils are toxic in a similar manner to Alzheimer's amyloid-β (Aβ and prion protein (PrP fibrils. Previous studies have shown that catalase binds to Aβ fibrils and appears to recognize a region containing the Gly-Ala-Ile-Ile sequence that is similar to the Gly-Ala-Ile-Leu sequence found in human IAPP residues 24-27. This study presents a transmission electron microscopy (TEM—based analysis of fibril formation and the binding of human erythrocyte catalase to IAPP fibrils. The results show that human IAPP 1-37, 8-37, and 20-29 peptides form fibrils with diverse and polymorphic structures. All three forms of IAPP bound catalase, and complexes of IAPP 1-37 or 8-37 with catalase were identified by immunoassay. The binding of biotinylated IAPP to catalase was high affinity with a KD of 0.77nM, and could be inhibited by either human or rat IAPP 1-37 and 8-37 forms. Fibrils formed by the PrP 118-135 peptide with a Gly-Ala-Val-Val sequence also bound catalase. These results suggest that catalase recognizes a Gly-Ala-Ile-Leu—like sequence in amyloid fibril-forming peptides. For IAPP 1-37 and 8-37, the catalase binding was primarily directed towards fibrillar rather than ribbon-like structures, suggesting differences in the accessibility of the human IAPP 24-27 Gly-Ala-Ile-Leu region. This suggests that catalase may be able to discriminate between different structural forms of IAPP fibrils. The ability of catalase to bind IAPP, Aβ, and PrP fibrils demonstrates the presence of similar accessible structural motifs that may be targets for antiamyloid therapeutic development.

  11. The impact of economic crises on communicable disease transmission and control: a systematic review of the evidence.

    Directory of Open Access Journals (Sweden)

    Marc Suhrcke

    Full Text Available There is concern among public health professionals that the current economic downturn, initiated by the financial crisis that started in 2007, could precipitate the transmission of infectious diseases while also limiting capacity for control. Although studies have reviewed the potential effects of economic downturns on overall health, to our knowledge such an analysis has yet to be done focusing on infectious diseases. We performed a systematic literature review of studies examining changes in infectious disease burden subsequent to periods of crisis. The review identified 230 studies of which 37 met our inclusion criteria. Of these, 30 found evidence of worse infectious disease outcomes during recession, often resulting from higher rates of infectious contact under poorer living circumstances, worsened access to therapy, or poorer retention in treatment. The remaining studies found either reductions in infectious disease or no significant effect. Using the paradigm of the "SIR" (susceptible-infected-recovered model of infectious disease transmission, we examined the implications of these findings for infectious disease transmission and control. Key susceptible groups include infants and the elderly. We identified certain high-risk groups, including migrants, homeless persons, and prison populations, as particularly vulnerable conduits of epidemics during situations of economic duress. We also observed that the long-term impacts of crises on infectious disease are not inevitable: considerable evidence suggests that the magnitude of effect depends critically on budgetary responses by governments. Like other emergencies and natural disasters, preparedness for financial crises should include consideration of consequences for communicable disease control.

  12. Chains of transmission and control of Ebola virus disease in Conakry, Guinea, in 2014: an observational study.

    Science.gov (United States)

    Faye, Ousmane; Boëlle, Pierre-Yves; Heleze, Emmanuel; Faye, Oumar; Loucoubar, Cheikh; Magassouba, N'Faly; Soropogui, Barré; Keita, Sakoba; Gakou, Tata; Bah, El Hadji Ibrahima; Koivogui, Lamine; Sall, Amadou Alpha; Cauchemez, Simon

    2015-03-01

    An epidemic of Ebola virus disease of unprecedented size continues in parts of west Africa. For the first time, large urban centres such as Conakry, the capital of Guinea, are affected. We did an observational study of patients with Ebola virus disease in three regions of Guinea, including Conakry, aiming to map the routes of transmission and assess the effect of interventions. Between Feb 10, 2014, and Aug 25, 2014, we obtained data from the linelist of all confirmed and probable cases in Guinea (as of Sept 16, 2014), a laboratory database of information about patients, and interviews with patients and their families and neighbours. With this information, we mapped chains of transmission, identified which setting infections most probably originated from (community, hospitals, or funerals), and computed the context-specific and overall reproduction numbers. Of 193 confirmed and probable cases of Ebola virus disease reported in Conakry, Boffa, and Télimélé, 152 (79%) were positioned in chains of transmission. Health-care workers contributed little to transmission. In March, 2014, individuals with Ebola virus disease who were not health-care workers infected a mean of 2·3 people (95% CI 1·6-3·2): 1·4 (0·9-2·2) in the community, 0·4 (0·1-0·9) in hospitals, and 0·5 (0·2-1·0) at funerals. After the implementation of infection control in April, the reproduction number in hospitals and at funerals reduced to lower than 0·1. In the community, the reproduction number dropped by 50% for patients that were admitted to hospital, but remained unchanged for those that were not. In March, hospital transmissions constituted 35% (seven of 20) of all transmissions and funeral transmissions constituted 15% (three); but from April to the end of the study period, they constituted only 9% (11 of 128) and 4% (five), respectively. 82% (119 of 145) of transmission occurred in the community and 72% (105) between family members. Our simulations show that a 10% increase in

  13. [Globalization, inequality, and transmission of tropical diseases in the Venezuelan Amazon].

    Science.gov (United States)

    Botto-Abella, Carlos; Graterol-Mendoza, Beatriz

    2007-01-01

    Economic globalization appears to be causing greater inequalities and increased vulnerability to tropical diseases around the world. The Venezuelan Amazon population, especially the rural indigenous population, displays among the worst health indicators in the Americas. High infant mortality rates in remote indigenous populations indicate that such communities have been affected by the globalization of disease, rather than favored by globalization of health. Globalization has also influenced public policies in the country, affecting the efficiency of control programs targeting tropical diseases. A new global pact for the sustainable development of the planet is needed, supported by the globalization of human values and rights. In Venezuela, new policies for the indigenous health sector, more resources, and greater autonomy could help reduce the inequities described here in the Venezuelan Amazon.

  14. Outbreak of Human Pneumonic Plague with Dog-to-Human and Possible Human-to-Human Transmission--Colorado, June-July 2014.

    Science.gov (United States)

    Runfola, Janine K; House, Jennifer; Miller, Lisa; Colton, Leah; Hite, Donna; Hawley, Alex; Mead, Paul; Schriefer, Martin; Petersen, Jeannine; Casaceli, Colleen; Erlandson, Kristine M; Foster, Clayton; Pabilonia, Kristy L; Mason, Gary; Douglas, John M

    2015-05-01

    On July 8, 2014, the Colorado Department of Public Health and Environment (CDPHE) laboratory identified Yersinia pestis, the bacterium that causes plague, in a blood specimen collected from a man (patient A) hospitalized with pneumonia. The organism had been previously misidentified as Pseudomonas luteola by an automated system in the hospital laboratory. An investigation led by Tri-County Health Department (TCHD) revealed that patient A's dog had died recently with hemoptysis. Three other persons who had contact with the dog, one of whom also had contact with patient A, were ill with fever and respiratory symptoms, including two with radiographic evidence of pneumonia. Specimens from the dog and all three human contacts yielded evidence of acute Y. pestis infection. One of the pneumonia cases might have resulted through human-to-human transmission from patient A, which would be the first such event reported in the United States since 1924. This outbreak highlights 1) the need to consider plague in the differential diagnosis of ill domestic animals, including dogs, in areas where plague is endemic; 2) the limitations of automated diagnostic systems for identifying rare bacteria such as Y. pestis; and 3) the potential for milder plague illness in patients taking antimicrobial agents. Hospital laboratorians should be aware of the limitations of automated identification systems, and clinicians should suspect plague in patients with clinically compatible symptoms from whom P. luteola is isolated.

  15. Role of Carbamylated Biomolecules in Human Diseases.

    Science.gov (United States)

    Badar, Asim; Arif, Zarina; Alam, Khursheed

    2018-04-01

    Carbamylation (or carbamoylation) is a non-enzymatic modification of biomolecules mediated by cyanate, a dissociation product of urea. Proteins are more sensitive to carbamylation. Two major sites of carbamylation reaction are: N α -amino moiety of a protein N-terminus and the N ɛ -amino moiety of proteins' lysine residues. In kidney diseases, urea accumulates and the burden of carbamylation increases. This may lead to alteration in the structure and function of many important proteins relevant in maintenance of homeostasis. Carbamylated proteins namely, carbamylated-haemoglobin and carbamylated-low density lipoprotein (LDL) have been implicated in hypoxia and atherosclerosis, respectively. Furthermore, carbamylation of insulin, oxytocin, and erythropoietin have caused changes in the action of these hormones vis-à-vis the metabolic pathways they control. In this short review, authors have compiled the data on role of carbamylated proteins, enzymes, hormones, LDL, and so on, in human diseases. © 2018 IUBMB Life, 70(4):267-275, 2018. © 2018 International Union of Biochemistry and Molecular Biology.

  16. Assembly of the Genome of the Disease Vector Aedes aegypti onto a Genetic Linkage Map Allows Mapping of Genes Affecting Disease Transmission

    KAUST Repository

    Juneja, Punita

    2014-01-30

    The mosquito Aedes aegypti transmits some of the most important human arboviruses, including dengue, yellow fever and chikungunya viruses. It has a large genome containing many repetitive sequences, which has resulted in the genome being poorly assembled - there are 4,758 scaffolds, few of which have been assigned to a chromosome. To allow the mapping of genes affecting disease transmission, we have improved the genome assembly by scoring a large number of SNPs in recombinant progeny from a cross between two strains of Ae. aegypti, and used these to generate a genetic map. This revealed a high rate of misassemblies in the current genome, where, for example, sequences from different chromosomes were found on the same scaffold. Once these were corrected, we were able to assign 60% of the genome sequence to chromosomes and approximately order the scaffolds along the chromosome. We found that there are very large regions of suppressed recombination around the centromeres, which can extend to as much as 47% of the chromosome. To illustrate the utility of this new genome assembly, we mapped a gene that makes Ae. aegypti resistant to the human parasite Brugia malayi, and generated a list of candidate genes that could be affecting the trait. © 2014 Juneja et al.

  17. Control of human parasitic diseases: Context and overview.

    Science.gov (United States)

    Molyneux, David H

    2006-01-01

    The control of parasitic diseases of humans has been undertaken since the aetiology and natural history of the infections was recognized and the deleterious effects on human health and well-being appreciated by policy makers, medical practitioners and public health specialists. However, while some parasitic infections such as malaria have proved difficult to control, as defined by a sustained reduction in incidence, others, particularly helminth infections can be effectively controlled. The different approaches to control from diagnosis, to treatment and cure of the clinically sick patient, to control the transmission within the community by preventative chemotherapy and vector control are outlined. The concepts of eradication, elimination and control are defined and examples of success summarized. Overviews of the health policy and financing environment in which programmes to control or eliminate parasitic diseases are positioned and the development of public-private partnerships as vehicles for product development or access to drugs for parasite disease control are discussed. Failure to sustain control of parasites may be due to development of drug resistance or the failure to implement proven strategies as a result of decreased resources within the health system, decentralization of health management through health-sector reform and the lack of financial and human resources in settings where per capita government expenditure on health may be less than $US 5 per year. However, success has been achieved in several large-scale programmes through sustained national government investment and/or committed donor support. It is also widely accepted that the level of investment in drug development for the parasitic diseases of poor populations is an unattractive option for pharmaceutical companies. The development of partnerships to specifically address this need provides some hope that the intractable problems of the treatment regimens for the trypanosomiases and

  18. Molecular Determinants of Human T-lymphotropic Virus Type 1 Transmission and Spread

    Directory of Open Access Journals (Sweden)

    Patrick L. Green

    2011-07-01

    Full Text Available Human T-lymphotrophic virus type-1 (HTLV-1 infects approximately 15 to 20 million people worldwide, with endemic areas in Japan, the Caribbean, and Africa. The virus is spread through contact with bodily fluids containing infected cells, most often from mother to child through breast milk or via blood transfusion. After prolonged latency periods, approximately 3 to 5% of HTLV-1 infected individuals will develop either adult T-cell leukemia/lymphoma (ATL, or other lymphocyte-mediated disorders such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP. The genome of this complex retrovirus contains typical gag, pol, and env genes, but also unique nonstructural proteins encoded from the pX region. These nonstructural genes encode the Tax and Rex regulatory proteins, as well as novel proteins essential for viral spread in vivo such as, p30, p12, p13 and the antisense encoded HBZ. While progress has been made in the understanding of viral determinants of cell transformation and host immune responses, host and viral determinants of HTLV-1 transmission and spread during the early phases of infection are unclear. Improvements in the molecular tools to test these viral determinants in cellular and animal models have provided new insights into the early events of HTLV-1 infection. This review will focus on studies that test HTLV-1 determinants in context to full length infectious clones of the virus providing insights into the mechanisms of transmission and spread of HTLV-1.

  19. Influence of breaking the symmetry between disease transmission and information propagation networks on stepwise decisions concerning vaccination

    International Nuclear Information System (INIS)

    Fukuda, Eriko; Tanimoto, Jun; Akimoto, Mitsuhiro

    2015-01-01

    Highlights: • We construct a model using epidemiological and vaccination dynamics. • We study effects of information propagation networks on disease propagation. • Information propagation networks affect the spatial structures of vaccinators. • Disease transmission network affects the information propagation network results. • Vaccination cost does not alter the effects of network-topology symmetry breaking. - Abstract: In previous epidemiological studies that address adaptive vaccination decisions, individuals generally act within a single network, which models the population structure. However, in reality, people are typically members of multiplex networks, which have various community structures. For example, a disease transmission network, which directly transmits infectious diseases, does not necessarily correspond with an information propagation network, in which individuals directly or indirectly exchange information concerning health conditions and vaccination strategies. The latter network may also be used for strategic interaction (strategy adaptation) concerning vaccination. Therefore, in order to reflect this feature, we consider the vaccination dynamics of structured populations whose members simultaneously belong to two types of networks: disease transmission and information propagation. Applying intensive numerical calculations, we determine that if the disease transmission network is modeled using a regular graph, such as a lattice population or random regular graph containing individuals of equivalent degrees, individuals should base their vaccination decisions on a different type of network. However, if the disease transmission network is a degree-heterogeneous graph, such as the Barabási–Albert scale-free network, which has a heterogeneous degree according to power low, then using the same network for information propagation more effectively prevents the spread of epidemics. Furthermore, our conclusions are unaffected by the relative

  20. The Sociospatial Network: Risk and the Role of Place in the Transmission of Infectious Diseases.

    Directory of Open Access Journals (Sweden)

    James J Logan

    Full Text Available Control of sexually transmitted infections and blood-borne pathogens is challenging due to their presence in groups exhibiting complex social interactions. In particular, sharing injection drug use equipment and selling sex (prostitution puts people at high risk. Previous work examining the involvement of risk behaviours in social networks has suggested that social and geographic distance of persons within a group contributes to these pathogens' endemicity. In this study, we examine the role of place in the connectedness of street people, selected by respondent driven sampling, in the transmission of blood-borne and sexually transmitted pathogens. A sample of 600 injection drug users, men who have sex with men, street youth and homeless people were recruited in Winnipeg, Canada from January to December, 2009. The residences of participants and those of their social connections were linked to each other and to locations where they engaged in risk activity. Survey responses identified 101 unique sites where respondents participated in injection drug use or sex transactions. Risk sites and respondents' residences were geocoded, with residence representing the individuals. The sociospatial network and estimations of geographic areas most likely to be frequented were mapped with network graphs and spatially using a Geographic Information System (GIS. The network with the most nodes connected 7.7% of respondents; consideration of the sociospatial network increased this to 49.7%. The mean distance between any two locations in the network was within 3.5 kilometres. Kernel density estimation revealed key activity spaces where the five largest networks overlapped. Here, the combination of spatial and social entities in network analysis defines the overlap of vulnerable populations in risk space, over and above the person to person links. Implications of this work are far reaching, not just for understanding transmission dynamics of sexually transmitted

  1. Vertically acquired hepatitis C virus infection: Correlates of transmission and disease progression.

    Science.gov (United States)

    Tovo, Pier-Angelo; Calitri, Carmelina; Scolfaro, Carlo; Gabiano, Clara; Garazzino, Silvia

    2016-01-28

    The worldwide prevalence of hepatitis C virus (HCV) infection in children is 0.05%-0.4% in developed countries and 2%-5% in resource-limited settings, where inadequately tested blood products or un-sterile medical injections still remain important routes of infection. After the screening of blood donors, mother-to-child transmission (MTCT) of HCV has become the leading cause of pediatric infection, at a rate of 5%. Maternal HIV co-infection is a significant risk factor for MTCT and anti-HIV therapy during pregnancy seemingly can reduce the transmission rate of both viruses. Conversely, a high maternal viral load is an important, but not preventable risk factor, because at present no anti-HCV treatment can be administered to pregnant women to block viral replication. Caution is needed in adopting obstetric procedures, such as amniocentesis or internal fetal monitoring, that can favor fetal exposure to HCV contaminated maternal blood, though evidence is lacking on the real risk of single obstetric practices. Mode of delivery and type of feeding do not represent significant risk factors for MTCT. Therefore, there is no reason to offer elective caesarean section or discourage breast-feeding to HCV infected parturients. Information on the natural history of vertical HCV infection is limited. The primary infection is asymptomatic in infants. At least one quarter of infected children shows a spontaneous viral clearance (SVC) that usually occurs within 6 years of life. IL-28B polymorphims and genotype 3 infection have been associated with greater chances of SVC. In general, HCV progression is mild or moderate in children with chronic infection who grow regularly, though cases with marked liver fibrosis or hepatic failure have been described. Non-organ specific autoantibodies and cryoglobulins are frequently found in children with chronic infection, but autoimmune diseases or HCV associated extrahepatic manifestations are rare.

  2. Maternal transmission of Alzheimer's disease: Prodromal metabolic phenotype and the search for genes

    Directory of Open Access Journals (Sweden)

    Mosconi Lisa

    2010-02-01

    Full Text Available Abstract After advanced age, having a parent affected with Alzheimer's disease (AD is the most significant risk factor for developing AD among cognitively normal (NL individuals. Although rare genetic mutations have been identified among the early-onset forms of familial AD (EOFAD, the genetics of the more common forms of late-onset AD (LOAD remain elusive. While some LOAD cases appear to be sporadic in nature, genetically mediated risk is evident from the familial aggregation of many LOAD cases. The patterns of transmission and biological mechanisms through which a family history of LOAD confers risk to the offspring are not known. Brain imaging studies using 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET have shown that NL individuals with a maternal history of LOAD, but not with a paternal family history, express a phenotype characterised by a pattern of progressive reductions of brain glucose metabolism, similar to that in AD patients. As maternally inherited AD may be associated with as many as 20 per cent of the total LOAD population, understanding the causes and mechanisms of expression of this form of AD is of great relevance. This paper reviews known genetic mutations implicated in EOFAD and their effects on brain chemistry, structure and function; epidemiology and clinical research findings in LOAD, including in vivo imaging findings showing selective patterns of hypometabolism in maternally inherited AD; possible genetic mechanisms involved in maternal transmission of AD, including chromosome X mutations, mitochondrial DNA and imprinting; and genetic mechanisms involved in other neurological disorders with known or suspected maternal inheritance. The review concludes with a discussion of the potential role of brain imaging for identifying endophenotypes in NL individuals at risk for AD, and for directing investigation of potential susceptibility genes for AD.

  3. Avian influenza shedding patterns in waterfowl: implications for surveillance, environmental transmission, and disease spread

    Science.gov (United States)

    Henaux, Viviane; Samuel, Michael D.

    2011-01-01

    Despite the recognized importance of fecal/oral transmission of low pathogenic avian influenza (LPAI) via contaminated wetlands, little is known about the length, quantity, or route of AI virus shed by wild waterfowl. We used published laboratory challenge studies to evaluate the length and quantity of low pathogenic (LP) and highly pathogenic (HP) virus shed via oral and cloacal routes by AI-infected ducks and geese, and how these factors might influence AI epidemiology and virus detection. We used survival analysis to estimate the duration of infection (from virus inoculation to the last day virus was shed) and nonlinear models to evaluate temporal patterns in virus shedding. We found higher mean virus titer and longer median infectious period for LPAI-infected ducks (10–11.5 days in oral and cloacal swabs) than HPAI-infected ducks (5 days) and geese (7.5 days). Based on the median bird infectious dose, we found that environmental contamination is two times higher for LPAI- than HPAI-infectious ducks, which implies that susceptible birds may have a higher probability of infection during LPAI than HPAI outbreaks. Less environmental contamination during the course of infection and previously documented shorter environmental persistence for HPAI than LPAI suggest that the environment is a less favorable reservoir for HPAI. The longer infectious period, higher virus titers, and subclinical infections with LPAI viruses favor the spread of these viruses by migratory birds in comparison to HPAI. Given the lack of detection of HPAI viruses through worldwide surveillance, we suggest monitoring for AI should aim at improving our understanding of AI dynamics (in particular, the role of the environment and immunity) using long-term comprehensive live bird, serologic, and environmental sampling at targeted areas. Our findings on LPAI and HPAI shedding patterns over time provide essential information to parameterize environmental transmission and virus spread in predictive

  4. The Sociospatial Network: Risk and the Role of Place in the Transmission of Infectious Diseases.

    Science.gov (United States)

    Logan, James J; Jolly, Ann M; Blanford, Justine I

    2016-01-01

    Control of sexually transmitted infections and blood-borne pathogens is challenging due to their presence in groups exhibiting complex social interactions. In particular, sharing injection drug use equipment and selling sex (prostitution) puts people at high risk. Previous work examining the involvement of risk behaviours in social networks has suggested that social and geographic distance of persons within a group contributes to these pathogens' endemicity. In this study, we examine the role of place in the connectedness of street people, selected by respondent driven sampling, in the transmission of blood-borne and sexually transmitted pathogens. A sample of 600 injection drug users, men who have sex with men, street youth and homeless people were recruited in Winnipeg, Canada from January to December, 2009. The residences of participants and those of their social connections were linked to each other and to locations where they engaged in risk activity. Survey responses identified 101 unique sites where respondents participated in injection drug use or sex transactions. Risk sites and respondents' residences were geocoded, with residence representing the individuals. The sociospatial network and estimations of geographic areas most likely to be frequented were mapped with network graphs and spatially using a Geographic Information System (GIS). The network with the most nodes connected 7.7% of respondents; consideration of the sociospatial network increased this to 49.7%. The mean distance between any two locations in the network was within 3.5 kilometres. Kernel density estimation revealed key activity spaces where the five largest networks overlapped. Here, the combination of spatial and social entities in network analysis defines the overlap of vulnerable populations in risk space, over and above the person to person links. Implications of this work are far reaching, not just for understanding transmission dynamics of sexually transmitted infections by

  5. Planning for Rift Valley fever virus: use of geographical information systems to estimate the human health threat of white-tailed deer (Odocoileus virginianus-related transmission

    Directory of Open Access Journals (Sweden)

    Sravan Kakani

    2010-11-01

    Full Text Available Rift Valley fever (RVF virus is a mosquito-borne phlebovirus of the Bunyaviridae family that causes frequent outbreaks of severe animal and human disease in sub-Saharan Africa, Egypt and the Arabian Peninsula. Based on its many known competent vectors, its potential for transmission via aerosolization, and its progressive spread from East Africa to neighbouring regions, RVF is considered a high-priority, emerging health threat for humans, livestock and wildlife in all parts of the world. Introduction of West Nile virus to North America has shown the potential for “exotic” viral pathogens to become embedded in local ecological systems. While RVF is known to infect and amplify within domestic livestock, such as taurine cattle, sheep and goats, if RVF virus is accidentally or intentionally introduced into North America, an important unknown factor will be the role of local wildlife in the maintenance or propagation of virus transmission. We examined the potential impact of RVF transmission via white-tailed deer (Odocoileus virginianus in a typical north-eastern United States urban-suburban landscape, where livestock are rare but where these potentially susceptible, ungulate wildlife are highly abundant. Model results, based on overlap of mosquito, human and projected deer densities, indicate that a significant proportion (497/1186 km2, i.e. 42% of the urban and peri-urban landscape could be affected by RVF transmission during the late summer months. Deer population losses, either by intervention for herd reduction or by RVF-related mortality, would substantially reduce these likely transmission zones to 53.1 km2, i.e. by 89%.

  6. Investigation of airborne foot-and-mouth disease virus transmission during low-wind conditions in the early phase of the UK 2001 epidemic

    Science.gov (United States)

    Mikkelsen, T.; Alexandersen, S.; Astrup, P.; Champion, H. J.; Donaldson, A. I.; Dunkerley, F. N.; Gloster, J.; Sørensen, J. H.; Thykier-Nielsen, S.

    2003-11-01

    Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed domesticated and wild animals. The highly contagious nature of FMD is a reflection of the wide range of host species, the enormous quantities of virus liberated by infected animals, the range of excretions and secretions which can be infectious, the stability of the virus in the environment, the multiplicity of routes of infection and the very small doses of the virus that can initiate infection. One of the mechanisms of spread is the carriage of droplets and droplet nuclei exhaled in the breath of infected animals. Such spread can be rapid and extensive, and it is known in certain circumstances to have transmitted disease over a distance of several hundred kilometres. During the 2001 FMD epidemic in the United Kingdom (UK), atmospheric dispersion models were applied in real time in order to assess the potential for atmospheric dispersion of the disease. The operational value of such modelling is primarily to identify premises which may have been exposed so that the human resources for surveillance and disease control purposes are employed most effectively. The paper describes the combined modelling techniques and presents the results obtained of detailed analyses performed during the early stages of the UK 2001 epidemic. This paper investigates the potential for disease spread in relation to two outbreaks (Burnside Farm, Heddon-on-the-Wall and Prestwick Hall Farm, Ponteland, Northumberland). A separate paper (Gloster et al., 2002) provides a more detailed analysis of the airborne disease transmission in the vicinity of Burnside Farm. The combined results are consistent with airborne transmission of disease to livestock in the Heddon-on-the-Wall area. Local topography may have played a significant role in influencing the pattern of disease spread.

  7. HLA-G and vertical mother-to-child transmission of human papillomavirus infection.

    Science.gov (United States)

    Louvanto, Karolina; Roger, Michel; Faucher, Marie-Claude; Syrjänen, Kari; Grenman, Seija; Syrjänen, Stina

    2018-06-01

    Role of host factors in transmission of human papillomavirus (HPV)-infection from mother to her offspring is not known. Our aim was to study whether human leukocyte antigen (HLA)-G allele concordance among the mother-child pairs could facilitate vertical transmission of HPV, because HLA-G may contribute to immune tolerance in pregnancy. Altogether, 310 mother-child pairs were included from the Finnish Family HPV study. Overall, nine different HLA-G alleles were identified. The HLA-G genotype concordance of G ∗ 01:01:01/01:04:01 increased the risk of high risk (HR)-HPV genotype positivity in cord blood and infant's oral mucosa. The mother-child concordance of G ∗ 01:01:02/01:01:02 increased the risk of oral HPV positivity with HR-HPV genotypes both in the mother and offspring; OR 2.45 (95%CI 1.24-4.85). Discordant HLA-G allele for G ∗ 01:04:01 and for G ∗ 01:06 was significantly associated with infant's oral low risk (LR)-HPV at birth, OR 3.07 (95%CI 1.01-9.36) and OR 5.19 (95%CI 1.22-22.03), respectively. HLA-G had no association with HPV genotype-specific concordance between the mother and child at birth nor influence on perinatal HPV status of the child. Taken together, our results show that HLA-G molecules have a role in predicting the newborn's likelihood for oral HPV infection at birth. Copyright © 2018 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.

  8. High Leptospira Diversity in Animals and Humans Complicates the Search for Common Reservoirs of Human Disease in Rural Ecuador.

    Science.gov (United States)

    Barragan, Veronica; Chiriboga, Jorge; Miller, Erin; Olivas, Sonora; Birdsell, Dawn; Hepp, Crystal; Hornstra, Heidie; Schupp, James M; Morales, Melba; Gonzalez, Manuel; Reyes, Soraya; de la Cruz, Carmen; Keim, Paul; Hartskeerl, Rudy; Trueba, Gabriel; Pearson, Talima

    2016-09-01

    Leptospirosis is a zoonotic disease responsible for high morbidity around the world, especially in tropical and low income countries. Rats are thought to be the main vector of human leptospirosis in urban settings. However, differences between urban and low-income rural communities provide additional insights into the epidemiology of the disease. Our study was conducted in two low-income rural communities near the coast of Ecuador. We detected and characterized infectious leptospira DNA in a wide variety of samples using new real time quantitative PCR assays and amplicon sequencing. We detected infectious leptospira in a high percentage of febrile patients (14.7%). In contrast to previous studies on leptospirosis risk factors, higher positivity was not found in rats (3.0%) but rather in cows (35.8%) and pigs (21.1%). Six leptospira species were identified (L. borgpetersenii, L kirschnerii, L santarosai, L. interrogans, L noguchii, and an intermediate species within the L. licerasiae and L. wolffii clade) and no significant differences in the species of leptospira present in each animal species was detected (χ2 = 9.89, adj.p-value = 0.27). A large portion of the world's human population lives in low-income, rural communities, however, there is limited information about leptospirosis transmission dynamics in these settings. In these areas, exposure to peridomestic livestock is particularly common and high prevalence of infectious leptospira in cows and pigs suggest that they may be the most important reservoir for human transmission. Genotyping clinical samples show that multiple species of leptospira are involved in human disease. As these genotypes were also detected in samples from a variety of animals, genotype data must be used in conjunction with epidemiological data to provide evidence of transmission and the importance of different potential leptospirosis reservoirs.

  9. Poultry food products--a source of avian influenza virus transmission to humans?

    Science.gov (United States)

    Harder, T C; Buda, S; Hengel, H; Beer, M; Mettenleiter, T C

    2016-02-01

    Global human mobility and intercontinental connectivity, expansion of livestock production and encroachment of wildlife habitats by invasive agricultural land use contribute to shape the complexity of influenza epidemiology. The OneHealth approach integrates these and further elements into considerations to improve disease control and prevention. Food of animal origin for human consumption is another integral aspect; if produced from infected livestock such items may act as vehicles of spread of animal pathogens, and, in case of zoonotic agents, as a potential human health hazard. Notifiable zoonotic avian influenza viruses (AIV) have become entrenched in poultry populations in several Asian and northern African countries since 2003. Highly pathogenic (HP) AIV (e.g. H5N1) cause extensive poultry mortality and severe economic losses. HPAIV and low pathogenic AIV (e.g. H7N9) with zoonotic propensities pose risks for human health. More than 1500 human cases of AIV infection have been reported, mainly from regions with endemically infected poultry. Intense human exposure to AIV-infected poultry, e.g. during rearing, slaughtering or processing of poultry, is a major risk factor for acquiring AIV infection. In contrast, human infections through consumption of AIV-contaminated food have not been substantiated. Heating poultry products according to kitchen standards (core temperatures ≥70°C, ≥10 s) rapidly inactivates AIV infectivity and renders fully cooked products safe. Nevertheless, concerted efforts must ensure that poultry products potentially contaminated with zoonotic AIV do not reach the food chain. Stringent and sustained OneHealth measures are required to better control and eventually eradicate, HPAIV from endemic regions. Copyright © 2015 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  10. Health Care Workers and Researchers Traveling to Developing-World Clinical Settings: Disease Transmission Risk and Mitigation

    Science.gov (United States)

    2010-01-01

    INVITED ARTICLE James M. Hughes and Mary E. Wilson, Section Editors Health Care Workers and Researchers Traveling to Developing-World Clinical...for risk mitigation. Few data on the epidemiology of infectious diseases occurring among traveling health care workers (HCWs) exist. Surveillance... Health Care Workers and Researchers Traveling to Developing-World Clinical Settings: Disease Transmission Risk and Mitigation 5a. CONTRACT NUMBER 5b

  11. Analogs of human genetic skin disease in domesticated animals

    Directory of Open Access Journals (Sweden)

    Justin Finch, MD

    2017-09-01

    The genetic skin diseases we will review are pigmentary mosaicism, piebaldism, albinism, Griscelli syndrome, ectodermal dysplasias, Waardenburg syndrome, and mucinosis in both humans and domesticated animals.

  12. Mannose-binding Lectin and the Risk of HIV Transmission and Disease Progression in Children A Systematic Review

    NARCIS (Netherlands)

    Israëls, Joël; Scherpbier, Henriette J.; Frakking, Florine N. J.; van de Wetering, Marianne D.; Kremer, Leontien C. M.; Kuijpers, Taco W.

    2012-01-01

    Background: Mannose-binding lectin (MBL) can activate the complement system by binding to carbohydrates, such as those presented on the HIV virion surface. It is unclear whether genetically determined MBL deficiency is related to vertical HIV transmission and disease progression in HIV-infected

  13. Glia and extracellular matrix changes affect extracellular diffusion and volume transmission in the brain in health and disease

    Czech Academy of Sciences Publication Activity Database

    Vargová, Lýdia; Syková, Eva

    2011-01-01

    Roč. 59, S1 (2011), S38 ISSN 0894-1491. [European meeting on Glia l Cells in Health and Disease /10./. 13.09.2011-17.09.2011, Prague] Institutional research plan: CEZ:AV0Z50390512; CEZ:AV0Z50390703 Keywords : diffusion * extracellular matrix * extrasynaptic transmission Subject RIV: FH - Neurology

  14. Quantification of foot and mouth disease virus excretion and transmission within groups of lambs with and without vaccination

    NARCIS (Netherlands)

    Orsel, K.; Dekker, A.; Bouma, A.; Stegeman, J.A.; Jong, de M.C.M.

    2007-01-01

    Sheep are well known to be susceptible for foot and mouth disease virus (FMDV), but it is unknown whether the infection can spread and persist in a sheep population. We therefore quantified virus transmission by performing experiments with FMD virus strain O/NET/2001 in groups of lambs. We used six

  15. Nosocomial transmission of sporadic Creutzfeldt-Jakob disease: results from a risk-based assessment of surgical interventions

    DEFF Research Database (Denmark)

    de Pedro-Cuesta, Jesús; Mahillo-Fernández, Ignacio; Rábano, Alberto

    2011-01-01

    Evidence of surgical transmission of sporadic Creutzfeldt-Jakob disease (sCJD) remains debatable in part due to misclassification of exposure levels. In a registry-based case-control study, the authors applied a risk-based classification of surgical interventions to determine the association...

  16. Partial Failure of Milk Pasteurization as a Risk for the Transmission of Campylobacter From Cattle to Humans.

    Science.gov (United States)

    Fernandes, Anand M; Balasegaram, Sooria; Willis, Caroline; Wimalarathna, Helen M L; Maiden, Martin C; McCarthy, Noel D

    2015-09-15

    Cattle are the second most common source of human campylobacteriosis. However, routes to account for this scale of transmission have not been identified. In contrast to chicken, red meat is not heavily contaminated at point of sale. Although effective pasteurization prevents milk-borne infection, apparently sporadic infections may include undetected outbreaks from raw or perhaps incompletely pasteurized milk. A rise in Campylobacter gastroenteritis in an isolated population was investigated using whole-genome sequencing (WGS), an epidemiological study, and environmental investigations. A single strain was identified in 20 cases, clearly distinguishable from other local strains and a reference population by WGS. A case-case analysis showed association of infection with the outbreak strain and milk from a single dairy (odds ratio, 8; Fisher exact test P value = .023). Despite temperature records indicating effective pasteurization, mechanical faults likely to lead to incomplete pasteurization of part of the milk were identified by further testing and examination of internal components of dairy equipment. Here, milk distribution concentrated on a small area, including school-aged children with low background incidence of campylobacteriosis, facilitated outbreak identification. Low-level contamination of widely distributed milk would not produce as detectable an outbreak signal. Such hidden outbreaks may contribute to the substantial burden of apparently sporadic Campylobacter from cattle where transmission routes are not certain. The effective discrimination of outbreak isolates from a reference population using WGS shows that integrating these data and approaches into surveillance could support the detection as well as investigation of such outbreaks. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.

  17. Human infectious disease burdens decrease with urbanization but not with biodiversity.

    Science.gov (United States)

    Wood, Chelsea L; McInturff, Alex; Young, Hillary S; Kim, DoHyung; Lafferty, Kevin D

    2017-06-05

    Infectious disease burdens vary from country to country and year to year due to ecological and economic drivers. Recently, Murray et al. (Murray CJ et al 2012 Lancet 380 , 2197-2223. (doi:10.1016/S0140-6736(12)61689-4)) estimated country-level morbidity and mortality associated with a variety of factors, including infectious diseases, for the years 1990 and 2010. Unlike other databases that report disease prevalence or count outbreaks per country, Murray et al. report health impacts in per-person disability-adjusted life years (DALYs), allowing comparison across diseases with lethal and sublethal health effects. We investigated the spatial and temporal relationships between DALYs lost to infectious disease and potential demographic, economic, environmental and biotic drivers, for the 60 intermediate-sized countries where data were available and comparable. Most drivers had unique associations with each disease. For example, temperature was positively associated with some diseases and negatively associated with others, perhaps due to differences in disease agent thermal optima, transmission modes and host species identities. Biodiverse countries tended to have high disease burdens, consistent with the expectation that high diversity of potential hosts should support high disease transmission. Contrary to the dilution effect hypothesis, increases in biodiversity over time were not correlated with improvements in human health, and increases in forestation over time were actually associated with increased disease burden. Urbanization and wealth were associated with lower burdens for many diseases, a pattern that could arise from increased access to sanitation and healthcare in cities and increased investment in healthcare. The importance of urbanization and wealth helps to explain why most infectious diseases have become less burdensome over the past three decades, and points to possible levers for further progress in improving global public health.This article is part

  18. Estefanofilariose em humanos: ocorrência e mecanismos de transmissão Stephanofilariasis in humans: occurrence and transmission mechanisms

    Directory of Open Access Journals (Sweden)

    Antonio Pereira de Novaes

    2007-04-01

    Full Text Available Descreve-se aqui o encontro do helminto Stephanofilaria spp., em dermatite nodular ulcerativa em seres humanos, sendo as ulceras pesquisadas de dimensões variadas e com alguns anos de existência. Acredita-se que, a presença desse parasita, que afeta diversas espécies de animais domésticos e silvestres, possa agravar o quadro com as lesões produzidas nos vasos venosos e linfáticos, reduzindo a circulação, retardando a cicatrização. O ciclo deste parasita no ser humano, também é descrito.This work describes the occurrence of the helminth Stephanofilaria spp in ulcerative nodular dermatitis in humans. The ulcers observed presented a variety of sizes and some years of existence. It is believed that the presence of this parasite, which affects several domestic and wild animal species, may harm human health through lesions produced in venous and lymphatic vessels that reduce blood circulation and retard the healing process. The cycle of this parasite in humans is also described.

  19. Transmission of sporadic Creutzfeldt-Jakob disease by blood transfusion: risk factor or possible biases.

    Science.gov (United States)

    Puopolo, Maria; Ladogana, Anna; Vetrugno, Vito; Pocchiari, Maurizio

    2011-07-01

    The occurrence of transfusion transmissions of variant Creutzfeldt-Jakob disease (CJD) cases has reawakened attention to the possible similar risk posed by other forms of CJD. CJD with a definite or probable diagnosis (sporadic CJD, n = 741; genetic CJD, n = 175) and no-CJD patients with definite alternative diagnosis (n = 482) with available blood transfusion history were included in the study. The risk of exposure to blood transfusion occurring more than 10 years before disease onset and for some possible confounding factors was evaluated by calculating crude odds ratios (ORs). Variables with significant ORs in univariate analyses were included in multivariate logistic regression analyses. In the univariate model, blood transfusion occurring more than 10 years before clinical onset is 4.1-fold more frequent in sporadic CJD than in other neurologic disorders. This significance is lost when the 10-year lag time was not considered. Multivariate analyses show that the risk of developing sporadic CJD after transfusion increases (OR, 5.05) after adjusting for possible confounding factors. Analysis conducted on patients with genetic CJD did not reveal any significant risk factor associated with transfusion. This is the first case-control study showing a significant risk of transfusion occurring more than 10 years before clinical onset in sporadic CJD patients. It remains questionable whether the significance of these data is biologically plausible or the consequence of biases in the design of the study, but they counterbalance previous epidemiologic negative reports that might have overestimated the assessment of blood safety in sporadic CJD. © 2010 American Association of Blood Banks.

  20. Factors determining the potential for onward transmission of variant Creutzfeldt–Jakob disease via surgical instruments

    Science.gov (United States)

    Garske, Tini; Ward, Hester J.T; Clarke, Paul; Will, Robert G; Ghani, Azra C

    2006-01-01

    While the number of variant Creutzfeldt–Jakob disease (vCJD) cases continues to decline, concern has been raised that transmission could occur directly from one person to another through routes including the transfer of blood and shared use of surgical instruments. Here we firstly present data on the surgical procedures undertaken on vCJD patients prior to onset of clinical symptoms, which supports the hypothesis that cases via this route are possible. We then apply a mathematical framework to assess the potential for self-sustaining epidemics via surgical procedures. Data from hospital episode statistics on the rates of high- and medium-risk procedures in the UK were used to estimate model parameters, and sensitivity to other unknown parameters about surgically transmitted vCJD was assessed. Our results demonstrate that a key uncertainty determining the scale of an epidemic and whether it is self-sustaining is the number of times a single instrument is re-used, alongside the infectivity of contaminated instruments and the effectiveness of cleaning. A survey into the frequency of re-use of surgical instruments would help reduce these uncertainties. PMID:17015298

  1. Transmission and adaptation of chronic wasting disease to hamsters and transgenic mice: evidence for strains.

    Science.gov (United States)

    Raymond, Gregory J; Raymond, Lynne D; Meade-White, Kimberly D; Hughson, Andrew G; Favara, Cynthia; Gardner, Donald; Williams, Elizabeth S; Miller, Michael W; Race, Richard E; Caughey, Byron

    2007-04-01

    In vitro screening using the cell-free prion protein conversion system indicated that certain rodents may be susceptible to chronic wasting disease (CWD). Therefore, CWD isolates from mule deer, white-tailed deer, and elk were inoculated intracerebrally into various rodent species to assess the rodents' susceptibility and to develop new rodent models of CWD. The species inoculated were Syrian golden, Djungarian, Chinese, Siberian, and Armenian hamsters, transgenic mice expressing the Syrian golden hamster prion protein, and RML Swiss and C57BL10 wild-type mice. The transgenic mice and the Syrian golden, Chinese, Siberian, and Armenian hamsters had limited susceptibility to certain of the CWD inocula, as evidenced by incomplete attack rates and long incubation periods. For serial passages of CWD isolates in Syrian golden hamsters, incubation periods rapidly stabilized, with isolates having either short (85 to 89 days) or long (408 to 544 days) mean incubation periods and distinct neuropathological patterns. In contrast, wild-type mouse strains and Djungarian hamsters were not susceptible to CWD. These results show that CWD can be transmitted and adapted to some species of rodents and suggest that the cervid-derived CWD inocula may have contained or diverged into at least two distinct transmissible spongiform encephalopathy strains.

  2. A proposal to reduce the risk of transmission of human papilloma virus via transvaginal ultrasound.

    Science.gov (United States)

    Combs, C Andrew; Fishman, Alan

    2016-07-01

    Three steps must be followed to prevent the transmission of infection via a contaminated transvaginal ultrasound probe: cleaning the probe after every use, high-level disinfection, and covering the probe with a single-use barrier during the examination. There may be critical flaws in at least 2 of these steps as they are currently practiced. First, 2 widely used disinfectants, glutaraldehyde and orthophthalaldehyde, have recently been found to be ineffective at neutralizing human papilloma virus type 16 and type 18. Second, commercial ultrasound probe covers have an unacceptable rate of leakage (8-81%) compared to condoms (0.9-2%). We recommend the use of a sonicated hydrogen peroxide disinfectant system rather than aldehyde-type disinfectants. We recommend that the probe be covered with a condom rather than a commercial probe cover during transvaginal ultrasound examination. Combined with probe cleaning, these 2 steps are estimated to result in an 800 million- to 250 billion-fold reduction in human papilloma virus viral load, which should translate to greatly enhanced patient safety. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Airborne Transmission of Melioidosis to Humans from Environmental Aerosols Contaminated with B. pseudomallei.

    Science.gov (United States)

    Chen, Pei-Shih; Chen, Yao-Shen; Lin, Hsi-Hsun; Liu, Pei-Ju; Ni, Wei-Fan; Hsueh, Pei-Tan; Liang, Shih-Hsiung; Chen, Chialin; Chen, Ya-Lei

    2015-06-01

    Melioidosis results from an infection with the soil-borne pathogen Burkholderia pseudomallei, and cases of melioidosis usually cluster after rains or a typhoon. In an endemic area of Taiwan, B. pseudomallei is primarily geographically distributed in cropped fields in the northwest of this area, whereas melioidosis cases are distributed in a densely populated district in the southeast. We hypothesized that contaminated cropped fields generated aerosols contaminated with B. pseudomallei, which were carried by a northwesterly wind to the densely populated southeastern district. We collected soil and aerosol samples from a 72 km2 area of land, including the melioidosis-clustered area and its surroundings. Aerosols that contained B. pseudomallei-specific TTSS (type III secretion system) ORF2 DNA were well distributed in the endemic area but were rare in the surrounding areas during the rainy season. The concentration of this specific DNA in aerosols was positively correlated with the incidence of melioidosis and the appearance of a northwesterly wind. Moreover, the isolation rate in the superficial layers of the contaminated cropped field in the northwest was correlated with PCR positivity for aerosols collected from the southeast over a 2-year period. According to pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) analyses, PFGE Type Ia (ST58) was the predominant pattern linking the molecular association among soil, aerosol and human isolates. Thus, the airborne transmission of melioidosis moves from the contaminated soil to aerosols and/or to humans in this endemic area.

  4. Consumption of Big Game Remains by Scavengers: A Potential Risk as Regards Disease Transmission in Central Spain

    Directory of Open Access Journals (Sweden)

    Ricardo Carrasco-Garcia

    2018-03-01

    Full Text Available Understanding the role that facultative scavenger species may play in spreading infectious pathogens, and even becoming reservoirs for humans, domestic and wild ungulates or, on the contrary, preventing the spread of disease, requires a prior understanding of the pattern of carrion scavenging in specific scenarios. The objectives of this paper are (i to describe the guild of vertebrate scavengers and (ii to study the species-specific, habitat, and management-related factors involved in the usage of gut piles in South Central Spain (SCS, a tuberculosis (TB endemic area. We used camera trapping at 18 hunting piles on seven hunting estates. A total of eight bird and five mammal taxa were detected at the remains of hunting piles. The most frequently detected species in terms of number of gut piles visited (78% and scavenged (61% was the red fox Vulpes vulpes, followed by the griffon vulture Gyps fulvus (56% as regards both presence and scavenging and the raven Corvus corax (61 and 39% as regards presence and scavenging, respectively. We evidenced that griffon vultures accounted for most of the scavenging activity in open habitats, while facultative mammal scavengers, red fox, and wild boar Sus scrofa made the highest contribution to scavenging in vegetation-covered habitats. In the case of wild boar, the gut piles deposited during the evening and night favored higher rates of scavenging, while the opposite pattern was observed for griffons. Overall, our findings suggest that when disposing of hunting remains in areas of risk as regards disease transmission it is particularly important to consider the access that facultative mammals, and especially wild boar, have to material, while the presence of the resource needs to be safeguarded to protect specialist scavengers of conservation value. These results are of particular relevance in the case of wild boar in the current context of re-emerging TB and emerging African swine fever (ASF in Europe.

  5. Transmission patterns of human enterovirus 71 to, from and among European countries, 2003 to 2013.

    Science.gov (United States)

    Hassel, Chervin; Mirand, Audrey; Lukashev, Alexander; TerletskaiaLadwig, Elena; Farkas, Agnes; Schuffenecker, Isabelle; Diedrich, Sabine; Huemer, Hartwig P; Archimbaud, Christine; Peigue-Lafeuille, Hélène; Henquell, Cécile; Bailly, Jean-Luc

    2015-01-01

    Enterovirus 71 (EV-71) is involved in epidemics of hand, foot, and mouth disease (HFMD) and has been reported to occur with severe neurological complications in eastern and south-east Asia. In other geographical areas, the transmission of this virus is poorly understood. We used large sequence datasets (of the gene encoding the viral protein 1, VP1) and a Bayesian phylogenetic approach to compare the molecular epidemiology and geographical spread patterns of EV-71 subgenogroups B4, B5, C1, C2, and C4 in Europe relative to other parts of the world. For the study, European countries considered were European Union (EU) Member States and Iceland, Norway and Switzerland. Viruses of the B4, B5, and C4 subgenogroups circulate mainly in eastern and south-east Asia. In Europe sporadic introductions of these subgenogroups are observed, however C1 and C2 viruses predominate. The phylogenies showed evidence of multiple events of spread involving C1 and C2 viruses within Europe since the mid-1990s. Two waves of sporadic C2 infections also occurred in 2010 and 2013. The 2007 Dutch outbreak caused by C2 and the occurrence of B5 and C4 infections in the EU between 2004 and 2013 arose while the circulation of C1 viruses was low. A transmission chain involving a C4 virus was traced from Japan to the EU and then further to Canada between 2001 and 2006. Recent events whereby spread of viruses have occurred from, to, and within Europe appear to be involved in the long term survival of EV-71, highlighting the need for enhanced surveillance of this virus.

  6. Systematic review of brucellosis in Kenya: disease frequency in humans and animals and risk factors for human infection

    Directory of Open Access Journals (Sweden)

    J. Njeru

    2016-08-01

    disease underreporting. We found no studies of disease incidence estimates or disease control efforts. Conclusion The risk for re-emergence and transmission of brucellosis is evident as a result of the co-existence of animal husbandry activities and social-cultural activities that promote brucellosis transmission. Well-designed countrywide, evidence-based, and multidisciplinary studies of brucellosis at the human/livestock/wildlife interface are needed. These could help to generate reliable frequency and potential impact estimates, to identify Brucella reservoirs, and to propose control strategies of proven efficacy.

  7. Systematic review of brucellosis in Kenya: disease frequency in humans and animals and risk factors for human infection.

    Science.gov (United States)

    Njeru, J; Wareth, G; Melzer, F; Henning, K; Pletz, M W; Heller, R; Neubauer, H

    2016-08-22

    incidence estimates or disease control efforts. The risk for re-emergence and transmission of brucellosis is evident as a result of the co-existence of animal husbandry activities and social-cultural activities that promote brucellosis transmission. Well-designed countrywide, evidence-based, and multidisciplinary studies of brucellosis at the human/livestock/wildlife interface are needed. These could help to generate reliable frequency and potential impact estimates, to identify Brucella reservoirs, and to propose control strategies of proven efficacy.

  8. A quantitative exposure model simulating human norovirus transmission during preparation of deli sandwiches.

    Science.gov (United States)

    Stals, Ambroos; Jacxsens, Liesbeth; Baert, Leen; Van Coillie, Els; Uyttendaele, Mieke

    2015-03-02

    Human noroviruses (HuNoVs) are a major cause of food borne gastroenteritis worldwide. They are often transmitted via infected and shedding food handlers manipulating foods such as deli sandwiches. The presented study aimed to simulate HuNoV transmission during the preparation of deli sandwiches in a sandwich bar. A quantitative exposure model was developed by combining the GoldSim® and @Risk® software packages. Input data were collected from scientific literature and from a two week observational study performed at two sandwich bars. The model included three food handlers working during a three hour shift on a shared working surface where deli sandwiches are prepared. The model consisted of three components. The first component simulated the preparation of the deli sandwiches and contained the HuNoV reservoirs, locations within the model allowing the accumulation of NoV and the working of intervention measures. The second component covered the contamination sources being (1) the initial HuNoV contaminated lettuce used on the sandwiches and (2) HuNoV originating from a shedding food handler. The third component included four possible intervention measures to reduce HuNoV transmission: hand and surface disinfection during preparation of the sandwiches, hand gloving and hand washing after a restroom visit. A single HuNoV shedding food handler could cause mean levels of 43±18, 81±37 and 18±7 HuNoV particles present on the deli sandwiches, hands and working surfaces, respectively. Introduction of contaminated lettuce as the only source of HuNoV resulted in the presence of 6.4±0.8 and 4.3±0.4 HuNoV on the food and hand reservoirs. The inclusion of hand and surface disinfection and hand gloving as a single intervention measure was not effective in the model as only marginal reductions of HuNoV levels were noticeable in the different reservoirs. High compliance of hand washing after a restroom visit did reduce HuNoV presence substantially on all reservoirs. The

  9. A Rare Case of Transfusion Transmission of Hepatitis A Virus to Two Patients with Haematological Disease.

    Science.gov (United States)

    da Silva, Suely Gonçalves Cordeiro; Leon, Luciane Almeida Amado; Alves, Gilda; Brito, Selma Magalhães; Sandes, Valcieny de Souza; Lima, Magda Maria Adorno Ferreira; Nogueira, Marta Colares; Tavares, Rita de Cássia Barbosa da Silva; Dobbin, Jane; Apa, Alexandre; de Paula, Vanessa Salete; Oliveira, Jaqueline Mendes de Oliveira; Pinto, Marcelo Alves; Ferreira, Orlando da Costa; Motta, Iara de Jesus Ferreira

    2016-03-01

    This paper describes the transmission of hepatitis A virus (HAV) to two blood recipients from a healthy donor that later presented to the blood bank with jaundice. The RNA of HAV was detected by qualitative nested reverse transcription polymerase chain reaction (nested RT-PCR) and quantified by real-time RT-PCR. HAV RNA samples were genotyped by direct sequencing of PCR products. A sequence from a fragment of 168 bp from the VP1/2A HAV region was used to construct a phylogenetic tree. A 31-year-old male donor accepted for donation of a whole blood unit returned to the blood bank with clinical jaundice 20 days after donation. His serological and NAT tests were negative for HBV and HCV. Serological tests for HAV IgM and IgG were negative on donation sample but positive on follow-up sample, confirming donor's HAV acute infection. Both recipients of red blood cells (R1) and platelet concentrate (R2) from the same implicated donation were HAV IgM-negative and IgG-positive. Qualitative PCR was positive on samples from all three individuals and phylogenetic analysis of viruses proved HAV transmission to the two recipients of blood products. HAV viral load on donor follow-up sample and the platelet recipient was 1.3 and 1.5 × 10(3) IU/ml, respectively. The RBC recipient, also infected by HCV, was undergoing bone marrow transplantation and died from fulminant hepatitis, 26 days after the implicated HAV transfusion. The blood donor, a garbage collector, spontaneously returned to the blood bank when developing jaundice. This highlights the importance of donor education to immediately report to blood banks of any signs and symptoms related to infectious disease developed after blood donation. The fact that one immunocompromised patient with HCV infection died from fulminant hepatitis after receiving a HAV-contaminated platelet transfusion underpins the importance of a HAV vaccination program for these group of patients.

  10. Puffy Skin Disease Is an Emerging Transmissible Condition in Rainbow Trout Oncorhynchus mykiss Walbaum.

    Science.gov (United States)

    Cano, Irene; Verner-Jeffreys, David W; van Aerle, Ronny; Paley, Richard K; Peeler, Edmund J; Green, Matthew; Rimmer, Georgina S E; Savage, Jacqueline; Joiner, Claire L; Bayley, Amanda E; Mewett, Jason; Hulland, Jonathan; Feist, Stephen W

    2016-01-01

    The transmission of puffy skin disease (PSD) to rainbow trout Oncorhynchus mykiss Walbaum was tested in the laboratory by conducting co-habitation challenges with puffy skin (PS)-affected fish (Trojans) collected from the field. Two separate challenges were conducted using Trojans sourced from two different sites and diploid (first trial) or triploid (second trial) naïve fish. PSD-specific clinical signs were observed in both groups of naïve fish, with 66% of the fish sampled during the challenges showing signs of varying severity. The first clinical features of PSD were presented as white oval skin patches on one or both flanks 15-21 days post-challenge (dpc). The extent of the lesions ranged from 10 to 90% of the body surface, depending on the severity of the lesion. Both the severity and number of affected fish increased during the challenge. Macroscopically, oedema of the skin and multifocal petechial haemorrhaging were observed towards the end of the trials. Abnormal fish behaviour consisting of "flashing" and excessive mucous production was noted from 15 dpc onwards. Fish with severe PSD lesions also displayed inappetence and associated emaciation. Rodlet cells were observed in 41% of the fresh skin scrapes analysed from the second trial. Histologically epidermal oedema was observed in 31% of the naive fish showing gross pathology, with additional 12% displaying epidermal hyperplasia, mostly observed at the end of the challenge. Other concomitant features of the PSD lesions in challenged fish were epithelial erosion and sloughing, and occasionally mild or focal inflammation. No consistent pathology of internal organs was observed. The parasites Ichthyophthirius multifiliis and Ichthyobodo necator were observed in skin samples of a proportion of naïve challenged fish and in Trojans but not in control fish. The presence of these and other known fish pathogens in the skin of PSD-fish was confirmed by high-throughput sequencing analysis. In summary, we have

  11. Safety evaluation of a recombinant myxoma-RHDV virus inducing horizontal transmissible protection against myxomatosis and rabbit haemorrhagic disease.

    Science.gov (United States)

    Torres, J M; Ramírez, M A; Morales, M; Bárcena, J; Vázquez, B; Espuña, E; Pagès-Manté, A; Sánchez-Vizcaíno, J M

    2000-09-15

    We have recently developed a transmissible vaccine to immunize rabbits against myxomatosis and rabbit haemorrhagic disease based on a recombinant myxoma virus (MV) expressing the rabbit haemorrhagic disease virus (RHDV) capsid protein [Bárcena et al. Horizontal transmissible protection against myxomatosis and rabbit haemorragic disease using a recombinant myxoma virus. J. Virol. 2000;74:1114-23]. Administration of the recombinant virus protects rabbits against lethal RHDV and MV challenges. Furthermore, the recombinant virus is capable of horizontal spreading promoting protection of contact animals, thus providing the opportunity to immunize wild rabbit populations. However, potential risks must be extensively evaluated before considering its field use. In this study several safety issues concerning the proposed vaccine have been evaluated under laboratory conditions. Results indicated that vaccine administration is safe even at a 100-fold overdose. No undesirable effects were detected upon administration to immunosuppressed or pregnant rabbits. The recombinant virus maintained its attenuated phenotype after 10 passages in vivo.

  12. Place-based social contact and mixing: a typology of generic meeting places of relevance for infectious disease transmission.

    Science.gov (United States)

    Strömgren, M; Holm, E; Dahlström, Ö; Ekberg, J; Eriksson, H; Spreco, A; Timpka, T

    2017-09-01

    This study aims to develop a typology of generic meeting places based on social contact and mixing of relevance for infectious disease transmission. Data were collected by means of a contact diary survey conducted on a representative sample of the Swedish population. The typology is derived from a cluster analysis accounting for four dimensions associated with transmission risk: visit propensity and its characteristics in terms of duration, number of other persons present and likelihood of physical contact. In the analysis, we also study demographic, socio-economic and geographical differences in the propensity of visiting meeting places. The typology identifies the family venue, the fixed activity site, the family vehicle, the trading plaza and the social network hub as generic meeting places. The meeting place typology represents a spatially explicit account of social contact and mixing relevant to infectious disease modelling, where the social context of the outbreak can be highlighted in light of the actual infectious disease.

  13. Zoonotic disease transmission associated with feral cats in a metropolitan area: A geospatial analysis.

    Science.gov (United States)

    Taetzsch, S J; Bertke, A S; Gruszynski, K R

    2018-06-01

    Feral cats raise public health concerns due to their large population numbers and ability to harbour pathogens that cause disease in people, pets, and wildlife. Information regarding the potential for feral cats to intersect with areas frequented by humans is lacking. This study examined the potential for feral cats and human territories to overlap in the Richmond metropolitan area of Central Virginia. Feral cats (n = 275) were trapped for monthly trap-neuter-release (TNR) clinics from July to November 2016. A geographic information system (GIS) was used to map feral cat trapping locations, elementary and preschools, public parks, and community gardens, and to evaluate the potential for cat interaction with these areas, presuming a maximum habitat radius of 0.44 miles. We found that 8.0% of feral cats in the Richmond metropolitan area had potential to range onto public elementary or preschool property, and 81.5% of feral cats trapped in Richmond City had potential to roam into one or more places of interest, including elementary and preschool grounds, public parks, and community gardens. This provides public health, veterinary, and human health professionals with important information that can be used to focus resources in an effort to reduce zoonosis associated with feral cat populations. © 2018 Blackwell Verlag GmbH.

  14. The Role of the Home Environment in the Transmission of Infectious Diseases.

    Science.gov (United States)

    Kagan, Lori J.; Aiello, Allison E.; Larson, Elaine

    2002-01-01

    Examines current health care literature on the microbiology of the home environment, summarizing evidence of transmission within the home and assessing the effectiveness of cleaning practices and products. The article focuses on the kitchen, bathroom, and laundry room, then looks at routes of transmission of infection within the home and discusses…

  15. Human papillomavirus 13 in a Mexican Mayan community with multifocal epithelial hyperplasia: could saliva be involved in household transmission?

    Science.gov (United States)

    Lopez-Villanueva, Maria Eugenia; Conde-Ferráez, Laura; Ayora-Talavera, Guadalupe; Cerón-Espinosa, Jose D; González-Losa, Maria del Refugio

    2011-01-01

    Multifocal epithelial hyperplasia (MEH) is a disease of the oral mucosa. Human papillomaviruses 13 and 32 have been detected in these lesions. We describe the epidemiology and clinical characteristics of patients with MEH in a rural community in the Mayan area of Mexico with 53 cases and 54 controls. Clinical and epidemiological data were collected through a direct interview. Oral cell samples were collected with a cytobrush. Subjects collected their own saliva sample in a sterile bottle. All samples were tested for HPV 13 and 32 by polymerase chain reaction using specific primers. Of the 53 patients and 54 healthy subjects, 56% were < 12 years old, 25% were males and 75% females. Evolution of the lesions was between two months and 17 years. The lesions affected lips, jugal mucosa, and tongue, 96% had multiple lesions. From 53 patients, fifty samples of oral cells and 31 samples of saliva were analyzed. HPV 13 was detected in 100% oral cell and 100% saliva samples studied. 16 healthy subjects were HVP 13 positive. A highly significant association of HPV 13 infection and MEH was found, as determined by chi square test (p = 0.00) Household transmission of HPV 13 may happen through saliva and the shared use of contaminated objects.

  16. Quantifying Transmission.

    Science.gov (United States)

    Woolhouse, Mark

    2017-07-01

    Transmissibility is the defining characteristic of infectious diseases. Quantifying transmission matters for understanding infectious disease epidemiology and designing evidence-based disease control programs. Tracing individual transmission events can be achieved by epidemiological investigation coupled with pathogen typing or genome sequencing. Individual infectiousness can be estimated by measuring pathogen loads, but few studies have directly estimated the ability of infected hosts to transmit to uninfected hosts. Individuals' opportunities to transmit infection are dependent on behavioral and other risk factors relevant given the transmission route of the pathogen concerned. Transmission at the population level can be quantified through knowledge of risk factors in the population or phylogeographic analysis of pathogen sequence data. Mathematical model-based approaches require estimation of the per capita transmission rate and basic reproduction number, obtained by fitting models to case data and/or analysis of pathogen sequence data. Heterogeneities in infectiousness, contact behavior, and susceptibility can have substantial effects on the epidemiology of an infectious disease, so estimates of only mean values may be insufficient. For some pathogens, super-shedders (infected individuals who are highly infectious) and super-spreaders (individuals with more opportunities to transmit infection) may be important. Future work on quantifying transmission should involve integrated analyses of multiple data sources.

  17. Transmission and immunopathology of the avian influenza virus A/Anhui/1/2013 (H7N9) human isolate in three commonly commercialized avian species.

    Science.gov (United States)

    Vidaña, B; Dolz, R; Busquets, N; Ramis, A; Sánchez, R; Rivas, R; Valle, R; Cordón, I; Solanes, D; Martínez, J; Majó, N

    2018-05-01

    H7N9 virus infection is a global concern, given that it can cause severe infection and mortality in humans. However, the understanding of H7N9 epidemiology, animal reservoir species and zoonotic risk remains limited. This work evaluates the pathogenicity, transmissibility and local innate immune response of three avian species harbouring different respiratory distribution of α2,6 and α2,3 SA receptors. Muscovy ducks, European quails and SPF chickens were intranasally inoculated with 10 5 embryo infectious dose (EID) 50 of the human H7N9 (A/Anhui/1/2013) influenza isolate. None of the avian species showed clinical signs or macroscopic lesions, and only mild microscopic lesions were observed in the upper respiratory tract of quail and chickens. Quail presented more severe histopathologic lesions and avian influenza virus (AIV) positivity by immunohistochemistry (IHC), which correlated with higher IL-6 responses. In contrast, Muscovy ducks were resistant to disease and presented higher IFNα and TLR7 response. In all species, viral shedding was higher in the respiratory than in the digestive tract. Higher viral shedding was observed in quail, followed by chicken and ducks, which presented similar viral titres. Efficient transmission was observed in all contact quail and half of the Muscovy ducks, while no transmission was observed between chicken. All avian species showed viral shedding in drinking water throughout infection. © 2017 Blackwell Verlag GmbH.

  18. Founder virus population related to route of virus transmission: a determinant of intrahost human immunodeficiency virus type 1 evolution?

    NARCIS (Netherlands)

    Lukashov, V. V.; Goudsmit, J.

    1997-01-01

    We and others have shown that in individual human immunodeficiency virus type 1 (HIV-1) infection, the adaptive evolution of HIV-1 is influenced by host immune competence. In this study, we tested the hypothesis that in addition to selective forces operating within the host, transmission bottlenecks

  19. Corticomuscular transmission of tremor signals by propriospinal neurons in Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Manzhao Hao

    Full Text Available Cortical oscillatory signals of single and double tremor frequencies act together to cause tremor in the peripheral limbs of patients with Parkinson's disease (PD. But the corticospinal pathway that transmits the tremor signals has not been clarified, and how alternating bursts of antagonistic muscle activations are generated from the cortical oscillatory signals is not well understood. This paper investigates the plausible role of propriospinal neurons (PN in C3-C4 in transmitting the cortical oscillatory signals to peripheral muscles. Kinematics data and surface electromyogram (EMG of tremor in forearm were collected from PD patients. A PN network model was constructed based on known neurophysiological connections of PN. The cortical efferent signal of double tremor frequencies were integrated at the PN network, whose outputs drove the muscles of a virtual arm (VA model to simulate tremor behaviors. The cortical efferent signal of single tremor frequency actuated muscle spindles. By comparing tremor data of PD patients and the results of model simulation, we examined two hypotheses regarding the corticospinal transmission of oscillatory signals in Parkinsonian tremor. Hypothesis I stated that the oscillatory cortical signals were transmitted via the mono-synaptic corticospinal pathways bypassing the PN network. The alternative hypothesis II stated that they were transmitted by way of PN multi-synaptic corticospinal pathway. Simulations indicated that without the PN network, the alternating burst patterns of antagonistic muscle EMGs could not be reliably generated, rejecting the first hypothesis. However, with the PN network, the alternating burst patterns of antagonist EMGs were naturally reproduced under all conditions of cortical oscillations. The results suggest that cortical commands of single and double tremor frequencies are further processed at PN to compute the alternating burst patterns in flexor and extensor muscles, and the

  20. Corticomuscular transmission of tremor signals by propriospinal neurons in Parkinson's disease.

    Science.gov (United States)

    Hao, Manzhao; He, Xin; Xiao, Qin; Alstermark, Bror; Lan, Ning

    2013-01-01

    Cortical oscillatory signals of single and double tremor frequencies act together to cause tremor in the peripheral limbs of patients with Parkinson's disease (PD). But the corticospinal pathway that transmits the tremor signals has not been clarified, and how alternating bursts of antagonistic muscle activations are generated from the cortical oscillatory signals is not well understood. This paper investigates the plausible role of propriospinal neurons (PN) in C3-C4 in transmitting the cortical oscillatory signals to peripheral muscles. Kinematics data and surface electromyogram (EMG) of tremor in forearm were collected from PD patients. A PN network model was constructed based on known neurophysiological connections of PN. The cortical efferent signal of double tremor frequencies were integrated at the PN network, whose outputs drove the muscles of a virtual arm (VA) model to simulate tremor behaviors. The cortical efferent signal of single tremor frequency actuated muscle spindles. By comparing tremor data of PD patients and the results of model simulation, we examined two hypotheses regarding the corticospinal transmission of oscillatory signals in Parkinsonian tremor. Hypothesis I stated that the oscillatory cortical signals were transmitted via the mono-synaptic corticospinal pathways bypassing the PN network. The alternative hypothesis II stated that they were transmitted by way of PN multi-synaptic corticospinal pathway. Simulations indicated that without the PN network, the alternating burst patterns of antagonistic muscle EMGs could not be reliably generated, rejecting the first hypothesis. However, with the PN network, the alternating burst patterns of antagonist EMGs were naturally reproduced under all conditions of cortical oscillations. The results suggest that cortical commands of single and double tremor frequencies are further processed at PN to compute the alternating burst patterns in flexor and extensor muscles, and the neuromuscular dynamics

  1. Generation of a non-transmissive Borna disease virus vector lacking both matrix and glycoprotein genes.

    Science.gov (United States)

    Fujino, Kan; Yamamoto, Yusuke; Daito, Takuji; Makino, Akiko; Honda, Tomoyuki; Tomonaga, Keizo

    2017-09-01

    Borna disease virus (BoDV), a prototype of mammalian bornavirus, is a non-segmented, negative strand RNA virus that often causes severe neurological disorders in infected animals, including horses and sheep. Unique among animal RNA viruses, BoDV transcribes and replicates non-cytopathically in the cell nucleus, leading to establishment of long-lasting persistent infection. This striking feature of BoDV indicates its potential as an RNA virus vector system. It has previously been demonstrated by our team that recombinant BoDV (rBoDV) lacking an envelope glycoprotein (G) gene develops persistent infections in transduced cells without loss of the viral genome. In this study, a novel non-transmissive rBoDV, rBoDV ΔMG, which lacks both matrix (M) and G genes in the genome, is reported. rBoDV-ΔMG expressing green fluorescence protein (GFP), rBoDV ΔMG-GFP, was efficiently generated in Vero/MG cells stably expressing both BoDV M and G proteins. Infection with rBoDV ΔMG-GFP was persistently maintained in the parent Vero cells without propagation within cell culture. The optimal ratio of M and G for efficient viral particle production by transient transfection of M and G expression plasmids into cells persistently infected with rBoDV ΔMG-GFP was also demonstrated. These findings indicate that the rBoDV ΔMG-based BoDV vector may provide an extremely safe virus vector system and could be a novel strategy for investigating the function of M and G proteins and the host range of bornaviruses. © 2017 The Societies and John Wiley & Sons Australia, Ltd.

  2. Entomologic index for human risk of Lyme disease.

    Science.gov (United States)

    Mather, T N; Nicholson, M C; Donnelly, E F; Matyas, B T

    1996-12-01

    An entomologic index based on density estimates of Lyme disease spirochete-infected nymphal deer ticks (lxodes scapularis) was developed to assess human risk of Lyme disease. The authors used a standardized protocol to determine tick density and infection in numerous forested sites in six Rhode Island towns. An entomologic risk index calculated for each town was compared with the number of human Lyme disease cases reported to the Rhode Island State Health Department for the same year. A strong positive relation between entomologic risk index and the Lyme disease case rate for each town suggested that the entomologic index was predictive of Lyme disease risk.

  3. Multi-criteria decision analysis and spatial statistic: an approach to determining human vulnerability to vector transmission of Trypanosoma cruzi

    Directory of Open Access Journals (Sweden)

    Diego Montenegro

    Full Text Available BACKGROUND Chagas disease (CD, caused by the protozoan Trypanosoma cruzi, is a neglected human disease. It is endemic to the Americas and is estimated to have an economic impact, including lost productivity and disability, of 7 billion dollars per year on average. OBJECTIVES To assess vulnerability to vector-borne transmission of T. cruzi in domiciliary environments within an area undergoing domiciliary vector interruption of T. cruzi in Colombia. METHODS Multi-criteria decision analysis [preference ranking method for enrichment evaluation (PROMETHEE and geometrical analysis for interactive assistance (GAIA methods] and spatial statistics were performed on data from a socio-environmental questionnaire and an entomological survey. In the construction of multi-criteria descriptors, decision-making processes and indicators of five determinants of the CD vector pathway were summarily defined, including: (1 house indicator (HI; (2 triatominae indicator (TI; (3 host/reservoir indicator (Ho/RoI; (4 ecotope indicator (EI; and (5 socio-cultural indicator (S-CI. FINDINGS Determination of vulnerability to CD is mostly influenced by TI, with 44.96% of the total weight in the model, while the lowest contribution was from S-CI, with 7.15%. The five indicators comprise 17 indices, and include 78 of the original 104 priority criteria and variables. The PROMETHEE and GAIA methods proved very efficient for prioritisation and quantitative categorisation of socio-environmental determinants and for better determining which criteria should be considered for interrupting the man-T. cruzi-vector relationship in endemic areas of the Americas. Through the analysis of spatial autocorrelation it is clear that there is a spatial dependence in establishing categories of vulnerability, therefore, the effect of neighbors’ setting (border areas on local values should be incorporated into disease management for establishing programs of surveillance and control of CD via vector

  4. Multi-criteria decision analysis and spatial statistic: an approach to determining human vulnerability to vector transmission of Trypanosoma cruzi.

    Science.gov (United States)

    Montenegro, Diego; Cunha, Ana Paula da; Ladeia-Andrade, Simone; Vera, Mauricio; Pedroso, Marcel; Junqueira, Angela

    2017-10-01

    Chagas disease (CD), caused by the protozoan Trypanosoma cruzi, is a neglected human disease. It is endemic to the Americas and is estimated to have an economic impact, including lost productivity and disability, of 7 billion dollars per year on average. To assess vulnerability to vector-borne transmission of T. cruzi in domiciliary environments within an area undergoing domiciliary vector interruption of T. cruzi in Colombia. Multi-criteria decision analysis [preference ranking method for enrichment evaluation (PROMETHEE) and geometrical analysis for interactive assistance (GAIA) methods] and spatial statistics were performed on data from a socio-environmental questionnaire and an entomological survey. In the construction of multi-criteria descriptors, decision-making processes and indicators of five determinants of the CD vector pathway were summarily defined, including: (1) house indicator (HI); (2) triatominae indicator (TI); (3) host/reservoir indicator (Ho/RoI); (4) ecotope indicator (EI); and (5) socio-cultural indicator (S-CI). Determination of vulnerability to CD is mostly influenced by TI, with 44.96% of the total weight in the model, while the lowest contribution was from S-CI, with 7.15%. The five indicators comprise 17 indices, and include 78 of the original 104 priority criteria and variables. The PROMETHEE and GAIA methods proved very efficient for prioritisation and quantitative categorisation of socio-environmental determinants and for better determining which criteria should be considered for interrupting the man-T. cruzi-vector relationship in endemic areas of the Americas. Through the analysis of spatial autocorrelation it is clear that there is a spatial dependence in establishing categories of vulnerability, therefore, the effect of neighbors' setting (border areas) on local values should be incorporated into disease management for establishing programs of surveillance and control of CD via vector. The study model proposed here is flexible and

  5. Comparative Analysis of Immune Checkpoint Molecules and Their Potential Role in the Transmissible Tasmanian Devil Facial Tumor Disease

    Directory of Open Access Journals (Sweden)

    Andrew S. Flies

    2017-05-01

    Full Text Available Immune checkpoint molecules function as a system of checks and balances that enhance or inhibit immune responses to infectious agents, foreign tissues, and cancerous cells. Immunotherapies that target immune checkpoint molecules, particularly the inhibitory molecules programmed cell death 1 and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4, have revolutionized human oncology in recent years, yet little is known about these key immune signaling molecules in species other than primates and rodents. The Tasmanian devil facial tumor disease is caused by transmissible cancers that have resulted in a massive decline in the wild Tasmanian devil population. We have recently demonstrated that the inhibitory checkpoint molecule PD-L1 is upregulated on Tasmanian devil (Sarcophilus harrisii facial tumor cells in response to the interferon-gamma cytokine. As this could play a role in immune evasion by tumor cells, we performed a thorough comparative analysis of checkpoint molecule protein sequences among Tasmanian devils and eight other species. We report that many of the key signaling motifs and ligand-binding sites in the checkpoint molecules are highly conserved across the estimated 162 million years of evolution since the last common ancestor of placental and non-placental mammals. Specifically, we discovered that the CTLA-4 (MYPPPY ligand-binding motif and the CTLA-4 (GVYVKM inhibitory domain are completely conserved across all nine species used in our comparative analysis, suggesting that the function of CTLA-4 is likely conserved in these species. We also found that cysteine residues for intra- and intermolecular disulfide bonds were also highly conserved. For instance, all 20 cysteine residues involved in disulfide bonds in the human 4-1BB molecule were also present in devil 4-1BB. Although many key sequences were conserved, we have also identified immunoreceptor tyrosine-based inhibitory motifs (ITIMs and immunoreceptor tyrosine-based switch

  6. Impact of rapid urbanization on mosquitoes and their disease transmission potential in Accra and Tema, Ghana.

    Science.gov (United States)

    Chinery, W A

    1995-06-01

    The total of 75 mosquito species recorded in Accra have declined to 28 species. Contributing factors to this decline and the reduction in prevalence of malaria and bancroftian filariasis in Accra presently include extensive water pollution and a fairly high daily mosquito mortality due to several factors including loss of natural adult resting places, use of mosquito repellents and the probable increase of Anopheles arabiensis population. Presently low yellow fever incidence is due inter alia to loss of its feral vectors and reduced intradomiciliary breeding of Aedes aegypti (L) although more common species like A. gambiae s.l., A. aegypti and C. p. quinquefasciatus could between them transmit many other arboviruses. However because of ready availability of human blood, spill-over of viruses from reservoir hosts to man will be rare. Ipso factor, malaria is the most common mosquito-borne disease with centripetal distribution of prevalence.

  7. Risk of transmission of Creutzfeldt-Jakob disease via blood and blood products. The French risk-analysis over the last 15 years.

    Science.gov (United States)

    Martin, M; Trouvin, J-H

    2013-09-01

    Risk of transmission of Creutzfeldt-Jakob disease (infectious agent, responsible of spongiform encephalopathy) via blood and blood components (including the plasma-derived medicinal products such as coagulation factors and immunoglobulins) have been a subject of concern for Health authorities since the early 1980s, with a regain of interest in the 1990s, with the bovine spongiform encephalopathy outbreak followed few years after with the notification of the first cases of variant Creutzfeldt-Jakob disease in humans. The risk-analysis and measures taken by the French authorities in the period 1990-2010 will be described with the various assumptions and working hypothesis used and revisited as new findings become available. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  8. Methods for estimating disease transmission rates: Evaluating the precision of Poisson regression and two novel methods

    DEFF Research Database (Denmark)

    Kirkeby, Carsten Thure; Hisham Beshara Halasa, Tariq; Gussmann, Maya Katrin

    2017-01-01

    the transmission rate. We use data from the two simulation models and vary the sampling intervals and the size of the population sampled. We devise two new methods to determine transmission rate, and compare these to the frequently used Poisson regression method in both epidemic and endemic situations. For most...... tested scenarios these new methods perform similar or better than Poisson regression, especially in the case of long sampling intervals. We conclude that transmission rate estimates are easily biased, which is important to take into account when using these rates in simulation models....

  9. Distinct transmissibility features of TSE sources derived from ruminant prion diseases by the oral route in a transgenic mouse model (TgOvPrP4 overexpressing the ovine prion protein.

    Directory of Open Access Journals (Sweden)

    Jean-Noël Arsac

    Full Text Available Transmissible spongiform encephalopathies (TSEs are a group of fatal neurodegenerative diseases associated with a misfolded form of host-encoded prion protein (PrP. Some of them, such as classical bovine spongiform encephalopathy in cattle (BSE, transmissible mink encephalopathy (TME, kuru and variant Creutzfeldt-Jakob disease in humans, are acquired by the oral route exposure to infected tissues. We investigated the possible transmission by the oral route of a panel of strains derived from ruminant prion diseases in a transgenic mouse model (TgOvPrP4 overexpressing the ovine prion protein (A136R154Q171 under the control of the neuron-specific enolase promoter. Sources derived from Nor98, CH1641 or 87V scrapie sources, as well as sources derived from L-type BSE or cattle-passaged TME, failed to transmit by the oral route, whereas those derived from classical BSE and classical scrapie were successfully transmitted. Apart from a possible effect of passage history of the TSE agent in the inocula, this implied the occurrence of subtle molecular changes in the protease-resistant prion protein (PrPres following oral transmission that can raises concerns about our ability to correctly identify sheep that might be orally infected by the BSE agent in the field. Our results provide proof of principle that transgenic mouse models can be used to examine the transmissibility of TSE agents by the oral route, providing novel insights regarding the pathogenesis of prion diseases.

  10. Nutrition, epigenetic mechanisms, and human disease

    National Research Council Canada - National Science Library

    Maulik, Nilanjana; Maulik, Gautam

    2011-01-01

    .... The text discusses the basics of nutrigenomics and epigenetic regulation, types of nutrition influencing genetic imprinting, and the role of nutrition in modulating an individual's predisposition to disease...

  11. The Transmission Chain Analysis of 2014–2015 Ebola Virus Disease Outbreak in Koinadugu District, Sierra Leone: An Observational Study

    Directory of Open Access Journals (Sweden)

    Ifeanyi-Stanley Muoghalu

    2017-07-01

    Full Text Available IntroductionSierra Leone experienced an unprecedented Ebola virus disease (EVD outbreak in all its districts. Koinadugu District was the last to report an EVD case. Several outbreak response strategies were implemented. As part of lessons learnt, we conducted an observational study to describe the transmission chain in the district and the impact of the control measures implemented to contain the outbreak.MethodsWe reconstructed the transmission chain, positioning both confirmed and probable cases, described the distribution of the EVD confirmed cases in the context of the routes of transmission (Community, Funeral or Health facility setting and assessed the impact of control measures using the surveillance data collected during the outbreak.ResultsAll 142 confirmed and probable EVD cases registered were fully resolved in the transmission chain. 72.5% of all the EVD cases in the district were exposed in the community, 26.1% exposed during funerals, and 1.4% exposed in the health facility setting. Health-care workers contributed little to the EVD outbreak. 71.1% of EVD transmission occurred among family members. Female EVD cases generated more secondary cases than their male counterparts (P = 0.03. With removal of EVD cases from the community and admission to the community care center (CCC, the EVD transmission in the community decreased to substantially lower rates. In addition, transmission due to exposure in health facilities was further reduced with the implementation of full infection and prevention controls.ConclusionThis study details the transmission chain of EVD in a rural district setting and the public health interventions implemented to successfully limit the outbreak to just one of 11 chiefdoms. Heightened community-based surveillance for early case detection, swift isolation of suspect cases, efficient contact tracing and monitoring, and good infection prevention and control measures in health facilities were highly effective in

  12. DNA multigene characterization of Fasciola hepatica and Lymnaea neotropica and its fascioliasis transmission capacity in Uruguay, with historical correlation, human report review and infection risk analysis

    Science.gov (United States)

    Gayo, Valeria; Sanchis, Jaime; Artigas, Patricio; Khoubbane, Messaoud; Birriel, Soledad; Mas-Coma, Santiago

    2017-01-01

    Background Fascioliasis is a pathogenic disease transmitted by lymnaeid snails and recently emerging in humans, in part due to effects of climate changes, anthropogenic environment modifications, import/export and movements of livestock. South America is the continent presenting more human fascioliasis hyperendemic areas and the highest prevalences and intensities known. These scenarios appear mainly linked to altitude areas in Andean countries, whereas lowland areas of non-Andean countries, such as Uruguay, only show sporadic human cases or outbreaks. A study including DNA marker sequencing of fasciolids and lymnaeids, an experimental study of the life cycle in Uruguay, and a review of human fascioliasis in Uruguay, are performed. Methodology/Principal findings The characterization of Fasciola hepatica from cattle and horses of Uruguay included the complete sequences of the ribosomal DNA ITS-2 and ITS-1 and mitochondrial DNA cox1 and nad1. ITS-2, ITS-1, partial cox1 and rDNA 16S gene of mtDNA were used for lymnaeids. Results indicated that vectors belong to Lymnaea neotropica instead of to Lymnaea viator, as always reported from Uruguay. The life cycle and transmission features of F. hepatica by L. neotropica of Uruguay were studied under standardized experimental conditions to enable a comparison with the transmission capacity of F. hepatica by Galba truncatula at very high altitude in Bolivia. On this baseline, we reviewed the 95 human fascioliasis cases reported in Uruguay and analyzed the risk of human infection in front of future climate change estimations. Conclusions/Significance The correlation of fasciolid and lymnaeid haplotypes with historical data on the introduction and spread of livestock into Uruguay allowed to understand the molecular diversity detected. Although Uruguayan L. neotropica is a highly efficient vector, its transmission capacity is markedly lower than that of Bolivian G. truncatula. This allows to understand the transmission and

  13. The utility of the new generation of humanized mice to study HIV-1 infection: transmission, prevention, pathogenesis, and treatment

    Directory of Open Access Journals (Sweden)

    Rowan Mark R

    2011-08-01

    Full Text Available Abstract Substantial improvements have been made in recent years in the ability to engraft human cells and tissues into immunodeficient mice. The use of human hematopoietic stem cells (HSCs leads to multi-lineage human hematopoiesis accompanied by production of a variety of human immune cell types. Population of murine primary and secondary lymphoid organs with human cells occurs, and long-term engraftment has been achieved. Engrafted cells are capable of producing human innate and adaptive immune responses, making these models the most physiologically relevant humanized animal models to date. New models have been successfully infected by a variety of strains of Human Immunodeficiency Virus Type 1 (HIV-1, accompanied by virus replication in lymphoid and non-lymphoid organs, including the gut-associated lymphoid tissue, the male and female reproductive tracts, and the brain. Multiple forms of virus-induced pathogenesis are present, and human T cell and antibody responses to HIV-1 are detected. These humanized mice are susceptible to a high rate of rectal and vaginal transmission of HIV-1 across an intact epithelium, indicating the potential to study vaccines and microbicides. Antiviral drugs, siRNAs, and hematopoietic stem cell gene therapy strategies have all been shown to be effective at reducing viral load and preventing or reversing helper T cell loss in humanized mice, indicating that they will serve as an important preclinical model to study new therapeutic modalities. HIV-1 has also been shown to evolve in response to selective pressures in humanized mice, thus showing that the model will be useful to study and/or predict viral evolution in response to drug or immune pressures. The purpose of this review is to summarize the findings reported to date on all new humanized mouse models (those transplanted with human HSCs in regards to HIV-1 sexual transmission, pathogenesis, anti-HIV-1 immune responses, viral evolution, pre- and post

  14. Fecal transmission of AA amyloidosis in the cheetah contributes to high incidence of disease

    Science.gov (United States)

    Zhang, Beiru; Une, Yumi; Fu, Xiaoying; Yan, Jingmin; Ge, FengXia; Yao, Junjie; Sawashita, Jinko; Mori, Masayuki; Tomozawa, Hiroshi; Kametani, Fuyuki; Higuchi, Keiichi

    2008-01-01

    AA amyloidosis is one of the principal causes of morbidity and mortality in captive cheetahs (Acinonyx jubatus), which are in danger of extinction, but little is known about the underlying mechanisms. Given the transmissible characteristics of AA amyloidosis, transmission between captive cheetahs may be a possible mechanism involved in the high incidence of AA amyloidosis. In this study of animals with AA amyloidosis, we found that cheetah feces contained AA amyloid fibrils that were different from those of the liver with regard to molecular weight and shape and had greater transmissibility. The infectious activity of fecal AA amyloid fibrils was reduced or abolished by the protein denaturants 6 M guanidine·HCl and formic acid or by AA immunodepletion. Thus, we propose that feces are a vehicle of transmission that may accelerate AA amyloidosis in captive cheetah populations. These results provide a pathogenesis for AA amyloidosis and suggest possible measures for rescuing cheetahs from extinction. PMID:18474855

  15. Identification of Risk Factors Associated with Transmission of Plague Disease in Eastern Zambia.

    Science.gov (United States)

    Nyirenda, Stanley S; Hang'ombe, Bernard M; Machang'u, Robert; Mwanza, Jackson; Kilonzo, Bukheti S

    2017-09-01

    Plague is a fatal, primarily rodent-flea-borne zoonotic disease caused by Yersinia pestis . The identification of risk factors of plague was investigated through questionnaire interview and conducting focus group discussion (FGD) in Sinda and Nyimba districts of eastern Zambia. A total of 104 questionnaires were administered to individual respondents and 20 groups consisting of 181 discussants, which comprised FGD team in this study. The study revealed that trapping, transportation, and preparation of rodents for food exposed the community to rodent and their fleas suggesting that plague may have occurred primarily by either flea bites or contact with infected wild rodents. The study also revealed that most people in communities consumed rodents as part of their regular diet; therefore, contact with small wild mammals was a common practice. The mode of transportation of freshly trapped rodents, in particular, carcasses risked human to flea bites. Questionnaire respondents (75%) and FGD discussants (55%) indicated that trappers preferred to carry rodent carcasses in small bags, whereas 55.8% and 20% respectively, reported hunters carrying carcasses in their pockets. Carrying of carcass skewers on trappers' shoulders was reported by 38.4% and 20% of individual respondents and FGD, respectively. All these activities were exposing humans to rodents and their fleas, the natural reservoirs and vectors of plague, respectively. This study also showed that there is a statistically significant (χ 2 = 4.6878, P < 0.05), between digging of rodents from their burrows and the presence of fleas on the hunter's bodies or clothes, which exposes humans to potentially flea bites in an enzootic cycle.

  16. Syphilis Networks in Louisiana: An Analysis of Network Configuration and Disease Transmission

    Science.gov (United States)

    Desmarais, Catherine Theresa

    Background: In 2009, Louisiana had the highest rate of primary and secondary syphilis in the country. Recent partner notification approaches have been insufficient in addressing Louisiana's deeply entrenched areas of syphilis infection. Prior researchers have suggested that surveillance systems may benefit from utilizing social and spatial network analysis in syphilis control efforts. Objective: To expand the understanding of the spread of syphilis in Louisiana, and to add new tools to the state's case finding resources through the description of the characteristics of cases of early syphilis and their partners in Louisiana, the socio-sexual networks of these cases, and the geospatial clustering of cases and partners. Methods: Utilizing state surveillance data, all cases of primary, secondary, and early latent syphilis that were diagnosed in 2009 and data on their sexual or needle sharing partners were analyzed using a combination of descriptive, network, and geospatial measures. Results: In 2009, Louisiana experienced a high rate of heterosexual syphilis transmission. Within syphilis transmission networks, 50.8% of all cases were female and 84.2% of all cases were black. The average and median ages of males with reactive syphilis tests were higher than that of females in Louisiana, and in 88.9% of regions, older individuals were more likely to have a syphilis test than no test. A greater proportion of males (11.4%) refused to discuss partners than females (7.4%) and a greater proportion of males (5.5%) refused testing and prophylactic treatment than females (2.8%). No distinct patterns were seen in disease prevalence between regions based upon demographic data. Classic summary network measures such as density, degree, centrality, and betweenness provided little information on similarities and differences between the different regions in Louisiana. All measures indicated low density and extreme fragmentation of networks in Louisiana. The majority of network

  17. Evaluation of Potential Infectivity of Alzheimer and Parkinson Disease Proteins in Recipients of Cadaver-Derived Human Growth Hormone

    Science.gov (United States)

    Irwin, David J.; Abrams, Joseph Y.; Schonberger, Lawrence B.; Leschek, Ellen Werber; Mills, James L.; Lee, Virginia M.-Y.; Trojanowski, John Q.

    2013-01-01

    Importance Growing evidence of cell-to-cell transmission of neurodegenerative disease (ND)–associated proteins (NDAPs) (ie, tau, Aβ, and α-synuclein) suggests possible similarities in the infectious prion protein (PrPsc) in spongiform encephalopathies. There are limited data on the potential human-to-human transmission of NDAPs associated with Alzheimer disease (AD) and other non-PrPsc ND. Objective To examine evidence for human-to-human transmission of AD, Parkinson disease (PD), and related NDAPs in cadaveric human growth hormone (c-hGH) recipients. Design We conducted a detailed immunohistochemical analysis of pathological NDAPs other than PrPsc in human pituitary glands. We also searched for ND in recipients of pituitary-derived c-hGH by reviewing the National Hormone and Pituitary Program (NHPP) cohort database and medical literature. Setting University-based academic center and agencies of the US Department of Health and Human Services. Participants Thirty-four routine autopsy subjects (10 non-ND controls and 24 patients with ND) and a US cohort of c-hGH recipients in the NHPP. Main Outcome Measures Detectable NDAPs in human pituitary sections and death certificate reports of non-PrPsc ND in the NHPP database. Results We found mild amounts of pathological tau, Aβ, and α-synuclein deposits in the adeno/neurohypophysis of patients with ND and control patients. No cases of AD or PD were identified, and 3 deaths attributed to amyotrophic lateral sclerosis (ALS) were found among US NHPP c-hGH recipients, including 2 of the 796 decedents in the originally confirmed NHPP c-hGH cohort database. Conclusions and Relevance Despite the likely frequent exposure of c-hGH recipients to NDAPs, and their markedly elevated risk of PrPsc-related disease, this population of NHPP c-hGH recipients does not appear to be at increased risk of AD or PD. We discovered 3 ALS cases of unclear significance among US c-hGH recipients despite the absence of pathological deposits of ALS

  18. The genus Malassezia and human disease

    Directory of Open Access Journals (Sweden)

    Inamadar A

    2003-07-01

    Full Text Available Sabouraud's Pityrosporum is now recognized as Malassezia. With taxonomic revision of the genus, newer species have been included. The role of this member of the normal human skin flora in different cutaneous and systemic disorders is becoming clearer. The immunological responses it induces in the human body are conflicting and their relevance to clinical features is yet to be explored.

  19. Using Human Induced Pluripotent Stem Cells to Model Skeletal Diseases.

    Science.gov (United States)

    Barruet, Emilie; Hsiao, Edward C

    2016-01-01

    Musculoskeletal disorders affecting the bones and joints are major health problems among children and adults. Major challenges such as the genetic origins or poor diagnostics of severe skeletal disease hinder our understanding of human skeletal diseases. The recent advent of human induced pluripotent stem cells (human iPS cells) provides an unparalleled opportunity to create human-specific models of human skeletal diseases. iPS cells have the ability to self-renew, allowing us to obtain large amounts of starting material, and have the potential to differentiate into any cell types in the body. In addition, they can carry one or more mutations responsible for the disease of interest or be genetically corrected to create isogenic controls. Our work has focused on modeling rare musculoskeletal disorders including fibrodysplasia ossificans progressive (FOP), a congenital disease of increased heterotopic ossification. In this review, we will discuss our experiences and protocols differentiating human iPS cells toward the osteogenic lineage and their application to model skeletal diseases. A number of critical challenges and exciting new approaches are also discussed, which will allow the skeletal biology field to harness the potential of human iPS cells as a critical model system for understanding diseases of abnormal skeletal formation and bone regeneration.

  20. Modeling human gastrointestinal inflammatory diseases using microphysiological culture systems.

    Science.gov (United States)

    Hartman, Kira G; Bortner, James D; Falk, Gary W; Ginsberg, Gregory G; Jhala, Nirag; Yu, Jian; Martín, Martín G; Rustgi, Anil K; Lynch, John P

    2014-09-01

    Gastrointestinal illnesses are a significant health burden for the US population, with 40 million office visits each year for gastrointestinal complaints and nearly 250,000 deaths. Acute and chronic inflammations are a common element of many gastrointestinal diseases. Inflammatory processes may be initiated by a chemical injury (acid reflux in the esophagus), an infectious agent (Helicobacter pylori infection in the stomach), autoimmune processes (graft versus host disease after bone marrow transplantation), or idiopathic (as in the case of inflammatory bowel diseases). Inflammation in these settings can contribute to acute complaints (pain, bleeding, obstruction, and diarrhea) as well as chronic sequelae including strictures and cancer. Research into the pathophysiology of these conditions has been limited by the availability of primary human tissues or appropriate animal models that attempt to physiologically model the human disease. With the many recent advances in tissue engineering and primary human cell culture systems, it is conceivable that these approaches can be adapted to develop novel human ex vivo systems that incorporate many human cell types to recapitulate in vivo growth and differentiation in inflammatory microphysiological environments. Such an advance in technology would improve our understanding of human disease progression and enhance our ability to test for disease prevention strategies and novel therapeutics. We will review current models for the inflammatory and immunological aspects of Barrett's esophagus, acute graft versus host disease, and inflammatory bowel disease and explore recent advances in culture methodologies that make these novel microphysiological research systems possible. © 2014 by the Society for Experimental Biology and Medicine.

  1. Genetic human prion disease modelled in PrP transgenic Drosophila.

    Science.gov (United States)

    Thackray, Alana M; Cardova, Alzbeta; Wolf, Hanna; Pradl, Lydia; Vorberg, Ina; Jackson, Walker S; Bujdoso, Raymond

    2017-09-20

    Inherited human prion diseases, such as fatal familial insomnia (FFI) and familial Creutzfeldt-Jakob disease (fCJD), are associated with autosomal dominant mutations in the human prion protein gene PRNP and accumulation of PrP Sc , an abnormal isomer of the normal host protein PrP C , in the brain of affected individuals. PrP Sc is the principal component of the transmissible neurotoxic prion agent. It is important to identify molecular pathways and cellular processes that regulate prion formation and prion-induced neurotoxicity. This will allow identification of possible therapeutic interventions for individuals with, or at risk from, genetic human prion disease. Increasingly, Drosophila has been used to model human neurodegenerative disease. An important unanswered question is whether genetic prion disease with concomitant spontaneous prion formation can be modelled in Drosophila We have used pUAST/PhiC31-mediated site-directed mutagenesis to generate Drosophila transgenic for murine or hamster PrP (prion protein) that carry single-codon mutations associated with genetic human prion disease. Mouse or hamster PrP harbouring an FFI (D178N) or fCJD (E200K) mutation showed mild Proteinase K resistance when expressed in Drosophila Adult Drosophila transgenic for FFI or fCJD variants of mouse or hamster PrP displayed a spontaneous decline in locomotor ability that increased in severity as the flies aged. Significantly, this mutant PrP-mediated neurotoxic fly phenotype was transferable to recipient Drosophila that expressed the wild-type form of the transgene. Collectively, our novel data are indicative of the spontaneous formation of a PrP-dependent neurotoxic phenotype in FFI- or CJD-PrP transgenic Drosophila and show that inherited human prion disease can be modelled in this invertebrate host. © 2017 The Author(s).

  2. Chronic Inflammatory Periodontal Disease in Patients with Human Immunodeficiency Virus.

    OpenAIRE

    Vania López Rodríguez; Emilio Carpio Muñoz; Vicente Fardales Macías; Iralys Benítez Guzmán

    2009-01-01

    Background: The Chronic Inflammatory Periodontal Disease is related with multiple risk factors. Those patients with human immunodeficiency virus have higher risk of presenting this disease and it is usually more serious in these cases. Objective: To describe the prevalence of Chronic Inflammatory Periodontal Disease in patients with HIV. Methods: Descriptive, observational, cross-sectional study including patients with HIV in Sancti Spiritus province. The occurrence of the disease was determi...

  3. Extracellular RNAs: development as biomarkers of human disease

    Directory of Open Access Journals (Sweden)

    Joseph F. Quinn

    2015-08-01

    Full Text Available Ten ongoing studies designed to test the possibility that extracellular RNAs may serve as biomarkers in human disease are described. These studies, funded by the NIH Common Fund Extracellular RNA Communication Program, examine diverse extracellular body fluids, including plasma, serum, urine and cerebrospinal fluid. The disorders studied include hepatic and gastric cancer, cardiovascular disease, chronic kidney disease, neurodegenerative disease, brain tumours, intracranial haemorrhage, multiple sclerosis and placental disorders. Progress to date and the plans for future studies are outlined.

  4. Epidemiological and genetic data supporting the transmission of Ancylostoma ceylanicum among human and domestic animals.

    Directory of Open Access Journals (Sweden)

    Romano Ngui

    Full Text Available BACKGROUND: Currently, information on species-specific hookworm infection is unavailable in Malaysia and is restricted worldwide due to limited application of molecular diagnostic tools. Given the importance of accurate identification of hookworms, this study was conducted as part of an ongoing molecular epidemiological investigation aimed at providing the first documented data on species-specific hookworm infection, associated risk factors and the role of domestic animals as reservoirs for hookworm infections in endemic communities of Malaysia. METHODS/FINDINGS: A total of 634 human and 105 domestic canine and feline fecal samples were randomly collected. The overall prevalence of hookworm in humans and animals determined via microscopy was 9.1% (95% CI = 7.0-11.7% and 61.9% (95% CI = 51.2-71.2%, respectively. Multivariate analysis indicated that participants without the provision of proper latrine systems (OR = 3.5; 95% CI = 1.53-8.00; p = 0.003, walking barefooted (OR = 5.6; 95% CI = 2.91-10.73; p<0.001 and in close contact with pets or livestock (OR = 2.9; 95% CI = 1.19-7.15; p = 0.009 were more likely to be infected with hookworms. Molecular analysis revealed that while most hookworm-positive individuals were infected with Necator americanus, Ancylostoma ceylanicum constituted 12.8% of single infections and 10.6% mixed infections with N. americanus. As for cats and dogs, 52.0% were positive for A. ceylanicum, 46.0% for Ancylostoma caninum and 2.0% for Ancylostoma braziliense and all were single infections. CONCLUSION: This present study provided evidence based on the combination of epidemiological, conventional diagnostic and molecular tools that A. ceylanicum infection is common and that its transmission dynamic in endemic areas in Malaysia is heightened by the close contact of human and domestic animal (i.e., dogs and cats populations.

  5. The drug sensitivity and transmission dynamics of human malaria on Nias Island, North Sumatra, Indonesia.

    Science.gov (United States)

    Fryauff, D J; Leksana, B; Masbar, S; Wiady, I; Sismadi, P; Susanti, A I; Nagesha, H S; Syafruddin; Atmosoedjono, S; Bangs, M J; Baird, J K

    2002-07-01

    Nias Island, off the north-western coast of Sumatra, Indonesia, was one of the first locations in which chloroquine-resistant Plasmodium vivax malaria was reported. This resistance is of particular concern because its ancient megalithic culture and the outstanding surfing conditions make the island a popular tourist destination. International travel to and from the island could rapidly spread chloroquine-resistant strains of P. vivax across the planet. The threat posed by such strains, locally and internationally, has led to the routine and periodic re-assessment of the efficacy of antimalarial drugs and transmission potential on the island. Active case detection identified malaria in 124 (17%) of 710 local residents whereas passive case detection, at the central health clinic, confirmed malaria in 77 (44%) of 173 cases of presumed 'clinical malaria'. Informed consenting volunteers who had malarial parasitaemias were treated, according to the Indonesian Ministry of Health's recommendations, with sulfadoxine-pyrimethamine (SP) on day 0 (for P. falciparum) or with chloroquine (CQ) on days 0, 1 and 2 (for P. vivax). Each volunteer was then monitored for clinical and parasite response until day 28. Recurrent parasitaemia by day 28 treatment was seen in 29 (83%) of the 35 P. falciparum cases given SP (14, 11 and four cases showing RI, RII and RIII resistance, respectively). Recurrent parasitaemia was also observed, between day 11 and day 21, in six (21%) of the 28 P. vivax cases given CQ. Although the results of quantitative analysis confirmed only low prevalences of CQ-resistant P. vivax malaria, the prevalence of SP resistance among the P. falciparum cases was among the highest seen in Indonesia. When the parasites present in the volunteers with P. falciparum infections were genotyped, mutations associated with pyrimethamine resistance were found at high frequency in the dhfr gene but there was no evidence of selection for sulfadoxine resistance in the dhps gene

  6. Disease emergence and resurgence—the wildlife-human connection

    Science.gov (United States)

    Friend, Milton; Hurley, James W.; Nol, Pauline; Wesenberg, Katherine

    2006-01-01

    In 2000, the Global Outbreak Alert and Response Network (GOARN) was organized as a global disease watchdog group to coordinate disease outbreak information and health crisis response. The World Health Organization (WHO) is the headquarters for this network. Understandably, the primary focus for WHO is human health. However, diseases such as the H5N1 avian influenza epizootic in Asian bird populations demonstrate the need for integrating knowledge about disease emergence in animals and in humans.Aside from human disease concerns, H5N1 avian influenza has major economic consequences for the poultry industry worldwide. Many other emerging diseases, such as severe acute respiratory syndrome (SARS), monkeypox, Ebola fever, and West Nile fever, also have an important wildlife component. Despite these wildlife associations, the true integration of the wildlife component in approaches towards disease emergence remains elusive. This separation between wildlife and other species’ interests is counterproductive because the emergence of zoonotic viruses and other pathogens maintained by wildlife reservoir hosts is poorly understood.This book is about the wildlife component of emerging diseases. It is intended to enhance the reader’s awareness of the role of wildlife in disease emergence. By doing so, perhaps a more holistic approach to disease prevention and control will emerge for the benefit of human, domestic animal, and free-ranging wildlife populations alike. The perspectives offered are influenced by more than four decades of my experiences as a wildlife disease practitioner. Although wildlife are victims to many of the same disease agents affecting humans and domestic animals, many aspects of disease in free-ranging wildlife require different approaches than those commonly applied to address disease in humans or domestic animals. Nevertheless, the broader community of disease investigators and health care professionals has largely pursued a separatist approach for

  7. Modelling multi-site transmission of the human papillomavirus and its impact on vaccination effectiveness

    Directory of Open Access Journals (Sweden)

    P. Lemieux-Mellouki

    2017-12-01

    Conclusions: Modelling genital-site only transmission may overestimate vaccination impact if extragenital infections contribute to systemic natural immunity or underestimate vaccination impact if a high proportion of genital infections originate from extragenital infections. Under current understanding of heterosexual HPV transmission and immunity, a substantial bias from using uni-site models in predicting vaccination effectiveness against genital HPV infection is unlikely to occur.

  8. A controlled human malaria infection model enabling evaluation of transmission-blocking interventions

    NARCIS (Netherlands)

    Collins, K.A.; Wang, C.Y.; Adams, M.; Mitchell, H.; Rampton, M.; Elliott, S.; Reuling, I.J.; Bousema, T.; Sauerwein, R.; Chalon, S.; Mohrle, J.J.; McCarthy, J.S.

    2018-01-01

    BACKGROUND: Drugs and vaccines that can interrupt the transmission of Plasmodium falciparum will be important for malaria control and elimination. However, models for early clinical evaluation of candidate transmission-blocking interventions are currently unavailable. Here, we describe a new model

  9. Low seroprevalence of human Lyme disease near a focus of high entomologic risk.

    Science.gov (United States)

    Rand, P W; Lacombe, E H; Smith, R P; Gensheimer, K; Dennis, D T

    1996-08-01

    To investigate a low rate of reported human Lyme disease adjacent to an area where the vector tick had become well established, we performed human and canine serosurveys and gathered data on environmental factors related to the risk of transmission. In March 1993, we obtained serum samples and conducted questionnaires that included information on outdoor activities, lot size, and frequency of deer sightings from 272 individuals living within a 5-km strip extending 12 km inland from a study site in south coastal Maine where collections revealed an abundant population of deer ticks. Serologic analysis was done using a flagellin-based enzyme-linked immunosorbent assay (ELISA) followed by Western immunoblot of positive and equivocal samples. Sera from 71 unvaccinated dogs within the study area were also analyzed for anti-Borrelia antibodies by ELISA. Human seropositivity was limited to two individuals living within 1.2 km of the coast. The frequency of daily deer sightings decreased sharply outside this area. Canine seropositivity, 100% within the first 0.8 km, decreased to 2% beyond 1.5 km. Canine serology appears to correlate with the entomologic indicators of the risk of Lyme disease transmission. Possible explanations for the low human seroprevalence are offered.

  10. Enhanced Human-Type Receptor Binding by Ferret-Transmissible H5N1 with a K193T Mutation.

    Science.gov (United States)

    Peng, Wenjie; Bouwman, Kim M; McBride, Ryan; Grant, Oliver C; Woods, Robert J; Verheije, Monique H; Paulson, James C; de Vries, Robert P

    2018-05-15

    All human influenza pandemics have originated from avian influenza viruses. Although multiple changes are needed for an avian virus to be able to transmit between humans, binding to human-type receptors is essential. Several research groups have reported mutations in H5N1 viruses that exhibit specificity for human-type receptors and promote respiratory droplet transmission between ferrets. Upon detailed analysis, we have found that these mutants exhibit significant differences in fine receptor specificity compared to human H1N1 and H3N2 and retain avian-type receptor binding. We have recently shown that human influenza viruses preferentially bind to α2-6-sialylated branched N-linked glycans, where the sialic acids on each branch can bind to receptor sites on two protomers of the same hemagglutinin (HA) trimer. In this binding mode, the glycan projects over the 190 helix at the top of the receptor-binding pocket, which in H5N1 would create a stearic clash with lysine at position 193. Thus, we hypothesized that a K193T mutation would improve binding to branched N-linked receptors. Indeed, the addition of the K193T mutation to the H5 HA of a respiratory-droplet-transmissible virus dramatically improves both binding to human trachea epithelial cells and specificity for extended α2-6-sialylated N-linked glycans recognized by human influenza viruses. IMPORTANCE Infections by avian H5N1 viruses are associated with a high mortality rate in several species, including humans. Fortunately, H5N1 viruses do not transmit between humans because they do not bind to human-type receptors. In 2012, three seminal papers have shown how these viruses can be engineered to transmit between ferrets, the human model for influenza virus infection. Receptor binding, among others, was changed, and the viruses now bind to human-type receptors. Receptor specificity was still markedly different compared to that of human influenza viruses. Here we report an additional mutation in ferret-transmissible

  11. Indigenous Australian household structure: a simple data collection tool and implications for close contact transmission of communicable diseases.

    Science.gov (United States)

    Vino, Thiripura; Singh, Gurmeet R; Davison, Belinda; Campbell, Patricia T; Lydeamore, Michael J; Robinson, Andrew; McVernon, Jodie; Tong, Steven Y C; Geard, Nicholas

    2017-01-01

    Households are an important location for the transmission of communicable diseases. Social contact between household members is typically more frequent, of greater intensity, and is more likely to involve people of different age groups than contact occurring in the general community. Understanding household structure in different populations is therefore fundamental to explaining patterns of disease transmission in these populations. Indigenous populations in Australia tend to live in larger households than non-Indigenous populations, but limited data are available on the structure of these households, and how they differ between remote and urban communities. We have developed a novel approach to the collection of household structure data, suitable for use in a variety of contexts, which provides a detailed view of age, gender, and room occupancy patterns in remote and urban Australian Indigenous households. Here we report analysis of data collected using this tool, which quantifies the extent of crowding in Indigenous households, particularly in remote areas. We use these data to generate matrices of age-specific contact rates, as used by mathematical models of infectious disease transmission. To demonstrate the impact of household structure, we use a mathematical model to simulate an influenza-like illness in different populations. Our simulations suggest that outbreaks in remote populations are likely to spread more rapidly and to a greater extent than outbreaks in non-Indigenous populations.

  12. Indigenous Australian household structure: a simple data collection tool and implications for close contact transmission of communicable diseases

    Directory of Open Access Journals (Sweden)

    Thiripura Vino

    2017-10-01

    Full Text Available Households are an important location for the transmission of communicable diseases. Social contact between household members is typically more frequent, of greater intensity, and is more likely to involve people of different age groups than contact occurring in the general community. Understanding household structure in different populations is therefore fundamental to explaining patterns of disease transmission in these populations. Indigenous populations in Australia tend to live in larger households than non-Indigenous populations, but limited data are available on the structure of these households, and how they differ between remote and urban communities. We have developed a novel approach to the collection of household structure data, suitable for use in a variety of contexts, which provides a detailed view of age, gender, and room occupancy patterns in remote and urban Australian Indigenous households. Here we report analysis of data collected using this tool, which quantifies the extent of crowding in Indigenous households, particularly in remote areas. We use these data to generate matrices of age-specific contact rates, as used by mathematical models of infectious disease transmission. To demonstrate the impact of household structure, we use a mathematical model to simulate an influenza-like illness in different populations. Our simulations suggest that outbreaks in remote populations are likely to spread more rapidly and to a greater extent than outbreaks in non-Indigenous populations.

  13. The transmission of vertical vibration through seats: Influence of the characteristics of the human body

    Science.gov (United States)

    Toward, Martin G. R.; Griffin, Michael J.

    2011-12-01

    The transmission of vibration through a seat depends on the impedance of the seat and the apparent mass of the seat occupant. This study was designed to determine how factors affecting the apparent mass of the body (age, gender, physical characteristics, backrest contact, and magnitude of vibration) affect seat transmissibility. The transmission of vertical vibration through a car seat was measured with 80 adults (41 males and 39 females aged 18-65) at frequencies between 0.6 and 20 Hz with two backrest conditions (no backrest and backrest), and with three magnitudes of random vibration (0.5, 1.0, and 1.5 m s -2 rms). Linear regression models were used to study the effects of subject physical characteristics (age, gender, and anthropometry) and features of their apparent mass (resonance frequency, apparent mass at resonance and at 12 Hz) on the measured seat transmissibility. The strongest predictor of both the frequency of the principal resonance in seat transmissibility and the seat transmissibility at resonance was subject age, with other factors having only marginal effects. The transmissibility of the seat at 12 Hz depended on subject age, body mass index, and gender. Although subject weight was strongly associated with apparent mass, weight was not strongly associated with seat transmissibility. The resonance frequency of the seat decreased with increases in the magnitude of the vibration excitation and increased when subjects made contact with the backrest. Inter-subject variability in the resonance frequency and transmissibility at resonance was less with greater vibration excitation, but was largely unaffected by backrest contact. A lumped parameter seat-person model showed that changes in seat transmissibility with age can be predicted from changes in apparent mass with age, and that the dynamic stiffness of the seat appeared to increase with increased loading so as to compensate for increases in subject apparent mass associated with increased sitting

  14. Disease Human - MDC_CardiovascularMortality2006

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Polygon feature class based on Zip Code boundaries showing the rate of deaths due to major cardiovascular diseases per 1000 residents of Miami-Dade County in 2006.

  15. Disease Human - MDC_CLRDMortality2006

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Polygon feature class based on Zip Code boundaries showing the rate of deaths per 100,000 residents due to Chronic Lower Respiratory Disease (CLRD) in Miami-Dade...

  16. The role of remote sensing and GIS for spatial prediction of vector-borne diseases transmission: a systematic review.

    Science.gov (United States)

    Palaniyandi, M

    2012-12-01

    There have been several attempts made to the appreciation of remote sensing and GIS for the study of vectors, biodiversity, vector presence, vector abundance and the vector-borne diseases with respect to space and time. This study was made for reviewing and appraising the potential use of remote sensing and GIS applications for spatial prediction of vector-borne diseases transmission. The nature of the presence and the abundance of vectors and vector-borne diseases, disease infection and the disease transmission are not ubiquitous and are confined with geographical, environmental and climatic factors, and are localized. The presence of vectors and vector-borne diseases is most complex in nature, however, it is confined and fueled by the geographical, climatic and environmental factors including man-made factors. The usefulness of the present day availability of the information derived from the satellite data including vegetation indices of canopy cover and its density, soil types, soil moisture, soil texture, soil depth, etc. is integrating the information in the expert GIS engine for the spatial analysis of other geoclimatic and geoenvironmental variables. The present study gives the detailed information on the classical studies of the past and present, and the future role of remote sensing and GIS for the vector-borne diseases control. The ecological modeling directly gives us the relevant information to understand the spatial variation of the vector biodiversity, vector presence, vector abundance and the vector-borne diseases in association with geoclimatic and the environmental variables. The probability map of the geographical distribution and seasonal variations of horizontal and vertical distribution of vector abundance and its association with vector -borne diseases can be obtained with low cost remote sensing and GIS tool with reliable data and speed.

  17. The impact of climate change on infectious disease transmission: perceptions of CDC health professionals in Shanxi Province, China.

    Science.gov (United States)

    Wei, Junni; Hansen, Alana; Zhang, Ying; Li, Hong; Liu, Qiyong; Sun, Yehuan; Xue, Shulian; Zhao, Shufang; Bi, Peng

    2014-01-01

    There have been increasing concerns about the challenge of emerging and re-emerging infectious diseases due to climate change, especially in developing countries including China. Health professionals play a significant role in the battle to control and prevent infectious diseases. This study therefore aims to investigate the perceptions and attitudes of health professionals at the Centers for Disease Control and Prevention (CDC) in different levels in China, and to consider adaptation measures to deal with the challenge of climate change. In 2013, a cross-sectional questionnaire survey was undertaken among 314 staff in CDCs in Shanxi Province, China, whose routine work involves disease control and prevention. Data were analyzed using descriptive methods and logistic regression. A majority of the CDC staff were aware of the health risks from climate change, especially its impacts on infectious disease transmission in their jurisdictions, and believed climate change might bring about both temporal and spatial change in transmission patterns. It was thought that adaptation measures should be established including: strengthening/improving currently existing disease surveillance systems and vector monitoring; building CDC capacity in terms of infrastructure and in-house health professional training; development and refinement of relevant legislation, policies and guidelines; better coordination among various government departments; the involvement of the community in infectious disease interventions; and collaborative research with other institutions. This study provides a snapshot of the understanding of CDC staff regarding climate change risks relevant to infectious diseases and adaptation in China. Results may help inform future efforts to develop adaptation measures to minimize infectious disease risks due to climate change.

  18. The impact of climate change on infectious disease transmission: perceptions of CDC health professionals in Shanxi Province, China.

    Directory of Open Access Journals (Sweden)

    Junni Wei

    Full Text Available There have been increasing concerns about the challenge of emerging and re-emerging infectious diseases due to climate change, especially in developing countries including China. Health professionals play a significant role in the battle to control and prevent infectious diseases. This study therefore aims to investigate the perceptions and attitudes of health professionals at the Centers for Disease Control and Prevention (CDC in different levels in China, and to consider adaptation measures to deal with the challenge of climate change. In 2013, a cross-sectional questionnaire survey was undertaken among 314 staff in CDCs in Shanxi Province, China, whose routine work involves disease control and prevention. Data were analyzed using descriptive methods and logistic regression. A majority of the CDC staff were aware of the health risks from climate change, especially its impacts on infectious disease transmission in their jurisdictions, and believed climate change might bring about both temporal and spatial change in transmission patterns. It was thought that adaptation measures should be established including: strengthening/improving currently existing disease surveillance systems and vector monitoring; building CDC capacity in terms of infrastructure and in-house health professional training; development and refinement of relevant legislation, policies and guidelines; better coordination among various government departments; the involvement of the community in infectious disease interventions; and collaborative research with other institutions. This study provides a snapshot of the understanding of CDC staff regarding climate change risks relevant to infectious diseases and adaptation in China. Results may help inform future efforts to develop adaptation measures to minimize infectious disease risks due to climate change.

  19. Borna disease virus and its role in the pathology of animals and humans

    Directory of Open Access Journals (Sweden)

    A. O. Mikheev

    2017-12-01

    shows the important role of the Borna disease virus in a variety of mental and behavioural changes in animals, both wild and domestic. However, the large amount of contradictory data and studies cannot yet provide a clear picture of the role of this virus in human pathology. On the one hand, there are clear data of the presence of RNA of the Bourna disease virus and antibodies to it in patients with psychoneurotic changes. On the other, there is no clear understanding of the infectivity of the virus in humans and its transmission from animals to humans and from person to person. These questions require further research and comprehensive study, particularly on the territory of Ukraine.

  20. Analyzing the Health Risks Resulting from Extending the 400kV High Voltage Transmission Lines on the Human

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    Mohammed Hassan Dervish

    2018-01-01

    Full Text Available Although it is difficult to imagine life without electricity, there are compiling confirmations show thatexposure to magnetic fields correlated electricity and radio frequencies pose magnificent hazards to human health. The most economist method to transfer electricity from power generation stations to users is by measures of high power transmission lines, buoyed by big transmission towers. The cables laced between the towers radiate magnetic and electric fields. In this research study, the magnetic field at ground level under 400 kV network lines extended in residential places have been conducted in two ways, mathematical calculation and practical measurement then the obtained results analyzed and compared with the international standards reference values. the reason of chose this type of transmission line is frequently using. The results indicate that they fall within the safe limiter commended by the WorldHealth Organization. the strength of radiation increasing with high of sea level and moisture ratiobecause of air ionization.

  1. HTLV-3/4 and simian foamy retroviruses in humans: discovery, epidemiology, cross-species transmission and molecular virology.

    Science.gov (United States)

    Gessain, Antoine; Rua, Réjane; Betsem, Edouard; Turpin, Jocelyn; Mahieux, Renaud

    2013-01-05

    Non-human primates are considered to be likely sources of viruses that can infect humans and thus pose a significant threat to human population. This is well illustrated by some retroviruses, as the simian immunodeficiency viruses and the simian T lymphotropic viruses, which have the ability to cross-species, adapt to a new host and sometimes spread. This leads to a pandemic situation for HIV-1 or an endemic one for HTLV-1. Here, we present the available data on the discovery, epidemiology, cross-species transmission and molecular virology of the recently discovered HTLV-3 and HTLV-4 deltaretroviruses, as well as the simian foamy retroviruses present in different human populations at risk, especially in central African hunters. We discuss also the natural history in humans of these retroviruses of zoonotic origin (magnitude and geographical distribution, possible inter-human transmission). In Central Africa, the increase of the bushmeat trade during the last decades has opened new possibilities for retroviral emergence in humans, especially in immuno-compromised persons. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. A cluster-randomised intervention trial against Schistosoma japonicum in the Peoples' Republic of China: bovine and human transmission.

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    Darren J Gray

    2009-06-01

    Full Text Available Zoonotic schistosomiasis japonica is a major public health problem in China. Bovines, particularly water buffaloes, are thought to play a major role in the transmission of schistosomiasis to humans in China. Preliminary results (1998-2003 of a praziquantel (PZQ-based pilot intervention study we undertook provided proof of principle that water buffaloes are major reservoir hosts for S. japonicum in the Poyang Lake region, Jiangxi Province.Here we present the results of a cluster-randomised intervention trial (2004-2007 undertaken in Hunan and Jiangxi Provinces, with increased power and more general applicability to the lake and marshlands regions of southern China. The trial involved four matched pairs of villages with one village within each pair randomly selected as a control (human PZQ treatment only, leaving the other as the intervention (human and bovine PZQ treatment. A sentinel cohort of people to be monitored for new infections for the duration of the study was selected from each village. Results showed that combined human and bovine chemotherapy with PZQ had a greater effect on human incidence than human PZQ treatment alone.The results from this study, supported by previous experimental evidence, confirms that bovines are the major reservoir host of human schistosomiasis in the lake and marshland regions of southern China, and reinforce the rationale for the development and deployment of a transmission blocking anti-S. japonicum vaccine targeting bovines.Australian New Zealand Clinical Trials Registry ACTRN12609000263291.

  3. A wireless transmission neural interface system for unconstrained non-human primates.

    Science.gov (United States)

    Fernandez-Leon, Jose A; Parajuli, Arun; Franklin, Robert; Sorenson, Michael; Felleman, Daniel J; Hansen, Bryan J; Hu, Ming; Dragoi, Valentin

    2015-10-01

    Studying the brain in large animal models in a restrained laboratory rig severely limits our capacity to examine brain circuits in experimental and clinical applications. To overcome these limitations, we developed a high-fidelity 96-channel wireless system to record extracellular spikes and local field potentials from the neocortex. A removable, external case of the wireless device is attached to a titanium pedestal placed in the animal skull. Broadband neural signals are amplified, multiplexed, and continuously transmitted as TCP/IP data at a sustained rate of 24 Mbps. A Xilinx Spartan 6 FPGA assembles the digital signals into serial data frames for transmission at 20 kHz though an 802.11n wireless data link on a frequency-shift key-modulated signal at 5.7-5.8 GHz to a receiver up to 10 m away. The system is powered by two CR123A, 3 V batteries for 2 h of operation. We implanted a multi-electrode array in visual area V4 of one anesthetized monkey (Macaca fascicularis) and in the dorsolateral prefrontal cortex (dlPFC) of a freely moving monkey (Macaca mulatta). The implanted recording arrays were electrically stable and delivered broadband neural data over a year of testing. For the first time, we compared dlPFC neuronal responses to the same set of stimuli (food reward) in restrained and freely moving conditions. Although we did not find differences in neuronal responses as a function of reward type in the restrained and unrestrained conditions, there were significant differences in correlated activity. This demonstrates that measuring neural responses in freely moving animals can capture phenomena that are absent in the traditional head-fixed paradigm. We implemented a wireless neural interface for multi-electrode recordings in freely moving non-human primates, which can potentially move systems neuroscience to a new direction by allowing one to record neural signals while animals interact with their environment.

  4. A wireless transmission neural interface system for unconstrained non-human primates

    Science.gov (United States)

    Fernandez-Leon, Jose A.; Parajuli, Arun; Franklin, Robert; Sorenson, Michael; Felleman, Daniel J.; Hansen, Bryan J.; Hu, Ming; Dragoi, Valentin

    2015-10-01

    Objective. Studying the brain in large animal models in a restrained laboratory rig severely limits our capacity to examine brain circuits in experimental and clinical applications. Approach. To overcome these limitations, we developed a high-fidelity 96-channel wireless system to record extracellular spikes and local field potentials from the neocortex. A removable, external case of the wireless device is attached to a titanium pedestal placed in the animal skull. Broadband neural signals are amplified, multiplexed, and continuously transmitted as TCP/IP data at a sustained rate of 24 Mbps. A Xilinx Spartan 6 FPGA assembles the digital signals into serial data frames for transmission at 20 kHz though an 802.11n wireless data link on a frequency-shift key-modulated signal at 5.7-5.8 GHz to a receiver up to 10 m away. The system is powered by two CR123A, 3 V batteries for 2 h of operation. Main results. We implanted a multi-electrode array in visual area V4 of one anesthetized monkey (Macaca fascicularis) and in the dorsolateral prefrontal cortex (dlPFC) of a freely moving monkey (Macaca mulatta). The implanted recording arrays were electrically stable and delivered broadband neural data over a year of testing. For the first time, we compared dlPFC neuronal responses to the same set of stimuli (food reward) in restrained and freely moving conditions. Although we did not find differences in neuronal responses as a function of reward type in the restrained and unrestrained conditions, there were significant differences in correlated activity. This demonstrates that measuring neural responses in freely moving animals can capture phenomena that are absent in the traditional head-fixed paradigm. Significance. We implemented a wireless neural interface for multi-electrode recordings in freely moving non-human primates, which can potentially move systems neuroscience to a new direction by allowing one to record neural signals while animals interact with their environment.

  5. Systemic administration of antiretrovirals prior to exposure prevents rectal and intravenous HIV-1 transmission in humanized BLT mice.

    Directory of Open Access Journals (Sweden)

    Paul W Denton

    2010-01-01

    Full Text Available Successful antiretroviral pre-exposure prophylaxis (PrEP for mucosal and intravenous HIV-1 transmission could reduce new infections among targeted high-risk populations including discordant couples, injection drug users, high-risk women and men who have sex with men. Targeted antiretroviral PrEP could be particularly effective at slowing the spread of HIV-1 if a single antiretroviral combination were found to be b