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Sample records for vector borne macroparasitic

  1. 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.

  2. 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.

  3. Vector borne diseases

    OpenAIRE

    Melillo Fenech, Tanya

    2010-01-01

    A vector-borne disease is one in which the pathogenic microorganism is transmitted from an infected individual to another individual by an arthropod or other agent. The transmission depends upon the attributes and requirements of at least three different Iiving organisms : the pathologic agent which is either a virus, protozoa, bacteria or helminth (worm); the vector, which is commonly an arthropod such as ticks or mosquitoes; and the human host.

  4. Vector-borne Infections

    Centers for Disease Control (CDC) Podcasts

    2011-04-18

    This podcast discusses emerging vector-borne pathogens, their role as prominent contributors to emerging infectious diseases, how they're spread, and the ineffectiveness of mosquito control methods.  Created: 4/18/2011 by National Center for Emerging Zoonotic and Infectious Diseases (NCEZID).   Date Released: 4/27/2011.

  5. Vector-borne diseases

    DEFF Research Database (Denmark)

    More, Simon J.; Bicout, Dominique; Bøtner, Anette

    2017-01-01

    After a request from the Europea n Commission, EFSA’s Panel on Animal Health and Welfaresummarised the main characteristics of 36 vector-borne disease s (VBDs) in 36 web-based storymaps.The risk of introduction in the EU through movement of livestock or pets was assessed for eac h of the36 VBDs......-agents for which the rate of introduction wasestimated to be very low, no further asse ssments were made. Due to the uncertainty related to someparameters used for the risk assessment or the instable or unpredictability disease situation in some ofthe source regions, it is recommended to update the assessment when...

  6. Emerging Vector-Borne Diseases.

    Science.gov (United States)

    Huntington, Mark K; Allison, Jay; Nair, Dilip

    2016-10-01

    Several mosquito-borne viral infections have recently emerged in North America; West Nile virus is the most common in the United States. Although West Nile virus generally causes a self-limited, flulike febrile illness, a serious neuroinvasive form may occur. Dengue is the most common vector-borne viral disease worldwide, and it has been a significant public health threat in the United States since 2009. Known as breakbone fever for its severe myalgias and arthralgias, dengue may cause a hemorrhagic syndrome. Chikungunya also causes flulike febrile illness and disabling arthralgias. Although meningoencephalitis may occur with chikungunya, bleeding is uncommon. Symptoms of Zika virus infection are similar to those of dengue, but milder. Zika virus increases the risk of fetal brain abnormalities, including microcephaly, if a pregnant woman is infected. Zika virus is spread through Aedes albopictus mosquito bites, is transmitted sexually, and may rarely spread nonsexually from person to person. Diagnosis of these vectorborne infections is clinical and serologic, and treatment is supportive. Other, well-established vector-borne diseases are also important. Ehrlichiosis is a tick-borne bacterial disease that presents as a nonspecific syndrome of fever, headache, malaise, and myalgias. It is diagnosed via blood smear testing, with confirmatory serology. Ehrlichiosis is treated with doxycycline. Rickettsial infections are transmitted by fleas, mites, and ticks, and severity ranges from mild to life threatening. Rocky Mountain spotted fever, the most significant rickettsial infection, is primarily a clinical diagnosis that presents as fever, headache, myalgias, petechial rash, and tick exposure. Doxycycline is effective for rickettsial infections if administered promptly. Vector avoidance strategies are critical to the prevention of all of these infections.

  7. [Climate- and vector-borne diseases

    DEFF Research Database (Denmark)

    Bygbjerg, I.C.; Schioler, K.L.; Konradsen, F.

    2009-01-01

    The predicted changes in climate have raised concerns that vector-borne diseases may emerge or expand in tempered regions. Malaria, leishmaniasis and tick-borne illnesses are discussed in terms of climate change and their endemic potential, especially in Denmark. While climate may play an important...

  8. Emerging vector borne diseases – incidence through vectors

    Directory of Open Access Journals (Sweden)

    Sara eSavic

    2014-12-01

    Full Text Available Vector borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowdays, in intercontinetal countries, there is a struggle with emerging diseases which have found their way to appear through vectors. Vector borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector borne infectious diseases and disease outbreaks. It could affect the range and popultion of pathogens, host and vectors, transmission season, etc. Reliable surveilance for diseases that are most likely to emerge is required. Canine vector borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, erlichiosis, leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fudamental role at primeraly prevention and then treatment of vector borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases.During a four year period, from 2009-2013, a total number of 551 dog samples were analysed for vector borne diseases (borreliosis, babesiosis, erlichiosis, anaplasmosis, dirofilariosis and leishmaniasis in routine laboratory work. The analysis were done by serological tests – ELISA for borreliosis, dirofilariosis and leishmaniasis, modified Knott test for dirofilariosis and blood smear for babesiosis, erlichiosis and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on avarege more then half of the samples

  9. Emerging Vector-Borne Diseases - Incidence through Vectors.

    Science.gov (United States)

    Savić, Sara; Vidić, Branka; Grgić, Zivoslav; Potkonjak, Aleksandar; Spasojevic, Ljubica

    2014-01-01

    Vector-borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowadays, in intercontinental countries, there is a struggle with emerging diseases, which have found their way to appear through vectors. Vector-borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens, and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector-borne infectious diseases and disease outbreaks. It could affect the range and population of pathogens, host and vectors, transmission season, etc. Reliable surveillance for diseases that are most likely to emerge is required. Canine vector-borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, ehrlichiosis, and leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fundamental role at primarily prevention and then treatment of vector-borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases. During a 4-year period, from 2009 to 2013, a total number of 551 dog samples were analyzed for vector-borne diseases (borreliosis, babesiosis, ehrlichiosis, anaplasmosis, dirofilariosis, and leishmaniasis) in routine laboratory work. The analysis was done by serological tests - ELISA for borreliosis, dirofilariosis, and leishmaniasis, modified Knott test for dirofilariosis, and blood smear for babesiosis, ehrlichiosis, and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on average more then half of the samples

  10. [Conflicts and vector-borne diseases

    DEFF Research Database (Denmark)

    Bygbjerg, Ib Christian

    2010-01-01

    Based on literature and personal experiences, vector-borne diseases and conflicts are reviewed. Simple rapid diagnostic tests for three important parasitoses are available. Resort is often made to case definitions and to presumptive treatment. Resistance is an emerging problem. Vaccines are still...... not available for most diseases. Promising preventive methods, including long-lasting impregnated bed-nets and tents, are available. War has been an impetus for disclosing life-cycles of vector-borne diseases and for control methods; peace, reconciliation and poverty reduction are required to achieve lasting...

  11. [Climate- and vector-borne diseases

    DEFF Research Database (Denmark)

    Bygbjerg, I.C.; Schioler, K.L.; Konradsen, F.

    2009-01-01

    The predicted changes in climate have raised concerns that vector-borne diseases may emerge or expand in tempered regions. Malaria, leishmaniasis and tick-borne illnesses are discussed in terms of climate change and their endemic potential, especially in Denmark. While climate may play an important...... role in disease patterns, it is evident that transmission potential is governed by a complex of factors, including socio-economy, health-care capacity and ecology. In Denmark, malaria and leishmaniasis are unlikely to become public health problems, whereas the potential for tick-borne illnesses may...

  12. [Conflicts and vector-borne diseases

    DEFF Research Database (Denmark)

    Bygbjerg, Ib Christian

    2010-01-01

    Based on literature and personal experiences, vector-borne diseases and conflicts are reviewed. Simple rapid diagnostic tests for three important parasitoses are available. Resort is often made to case definitions and to presumptive treatment. Resistance is an emerging problem. Vaccines are still...

  13. VECTOR BORNE TRANSMISSIBLE ZOONOSES IN MONTENEGRO

    Directory of Open Access Journals (Sweden)

    Gordana Mijovic

    2012-02-01

    Full Text Available Vector borne transmissible zoonoses are becoming more and more important in the group of emerging and re-emerging infections. We present the characteristics and actuality of this group of infectious diseases in Montenegro for the period 1998 - 2011. In examinations, standard epidemiological, clinical, serological, pathohistological diagnostic methods are employed. Natural conditions in Montenegro make it an important endemic area for more vector borne transmissible zoonoses. The changes of ecological characteristics, the vectors and infective agents, present the accidence for expansion and increasing importance of these infections in national pathology. According to the fact that it is an international port of nautical, continental and air traffic, Montenegro has responsibility for control and management of diseases belonging to the group of the travel and tropical diseases.

  14. Zoonotic aspects of vector-borne infections.

    Science.gov (United States)

    Failloux, A-B; Moutailler, S

    2015-04-01

    Vector-borne diseases are principally zoonotic diseases transmitted to humans by animals. Pathogens such as bacteria, parasites and viruses are primarily maintained within an enzootic cycle between populations of non-human primates or other mammals and largely non-anthropophilic vectors. This 'wild' cycle sometimes spills over in the form of occasional infections of humans and domestic animals. Lifestyle changes, incursions by humans into natural habitats and changes in agropastoral practices create opportunities that make the borders between wildlife and humans more permeable. Some vector-borne diseases have dispensed with the need for amplification in wild or domestic animals and they can now be directly transmitted to humans. This applies to some viruses (dengue and chikungunya) that have caused major epidemics. Bacteria of the genus Bartonella have reduced their transmission cycle to the minimum, with humans acting as reservoir, amplifier and disseminator. The design of control strategies for vector-borne diseases should be guided by research into emergence mechanisms in order to understand how a wild cycle can produce a pathogen that goes on to cause devastating urban epidemics.

  15. Canine vector-borne diseases in Brazil

    Science.gov (United States)

    Dantas-Torres, Filipe

    2008-01-01

    Canine vector-borne diseases (CVBDs) are highly prevalent in Brazil and represent a challenge to veterinarians and public health workers, since some diseases are of great zoonotic potential. Dogs are affected by many protozoa (e.g., Babesia vogeli, Leishmania infantum, and Trypanosoma cruzi), bacteria (e.g., Anaplasma platys and Ehrlichia canis), and helminths (e.g., Dirofilaria immitis and Dipylidium caninum) that are transmitted by a diverse range of arthropod vectors, including ticks, fleas, lice, triatomines, mosquitoes, tabanids, and phlebotomine sand flies. This article focuses on several aspects (etiology, transmission, distribution, prevalence, risk factors, diagnosis, control, prevention, and public health significance) of CVBDs in Brazil and discusses research gaps to be addressed in future studies. PMID:18691408

  16. Canine vector-borne diseases in Brazil

    Directory of Open Access Journals (Sweden)

    Dantas-Torres Filipe

    2008-08-01

    Full Text Available Abstract Canine vector-borne diseases (CVBDs are highly prevalent in Brazil and represent a challenge to veterinarians and public health workers, since some diseases are of great zoonotic potential. Dogs are affected by many protozoa (e.g., Babesia vogeli, Leishmania infantum, and Trypanosoma cruzi, bacteria (e.g., Anaplasma platys and Ehrlichia canis, and helminths (e.g., Dirofilaria immitis and Dipylidium caninum that are transmitted by a diverse range of arthropod vectors, including ticks, fleas, lice, triatomines, mosquitoes, tabanids, and phlebotomine sand flies. This article focuses on several aspects (etiology, transmission, distribution, prevalence, risk factors, diagnosis, control, prevention, and public health significance of CVBDs in Brazil and discusses research gaps to be addressed in future studies.

  17. Risk based surveillance for vector borne diseases

    DEFF Research Database (Denmark)

    Bødker, Rene

    of samples and hence early detection of outbreaks. Models for vector borne diseases in Denmark have demonstrated dramatic variation in outbreak risk during the season and between years. The Danish VetMap project aims to make these risk based surveillance estimates available on the veterinarians smart phones...... in Northern Europe. This model approach may be used as a basis for risk based surveillance. In risk based surveillance limited resources for surveillance are targeted at geographical areas most at risk and only when the risk is high. This makes risk based surveillance a cost effective alternative...... sample to a diagnostic laboratory. Risk based surveillance models may reduce this delay. An important feature of risk based surveillance models is their ability to continuously communicate the level of risk to veterinarians and hence increase awareness when risk is high. This is essential for submission...

  18. Survey of spatial distribution of vector-borne disease in ...

    African Journals Online (AJOL)

    Neighborhood dogs may act as reservoirs and disseminators of vector-borne diseases in urban areas. Accordingly, the aim of this study was to ascertain the health status and the vector-borne pathogens infecting dogs living in public areas with high levels of human movement in the city of Curitiba, southern Brazil.

  19. Vectors, viscin, and Viscaceae: mistletoes as parasites, mutualists, and resources.

    Science.gov (United States)

    Juliann E. Aukema

    2003-01-01

    Mistletoes are aerial, hemiparasitic plants found on trees throughout the world. They have unique ecological arrangements with the host plants they parasitize and the birds that disperse their seeds. Similar in many respects to vector-borne macroparasites, mistletoes are often detrimental to their hosts, and can even kill them. Coevolution has led to resistance...

  20. Air travel and vector-borne disease movement.

    Science.gov (United States)

    Tatem, A J; Huang, Z; Das, A; Qi, Q; Roth, J; Qiu, Y

    2012-12-01

    Recent decades have seen substantial expansions in the global air travel network and rapid increases in traffic volumes. The effects of this are well studied in terms of the spread of directly transmitted infections, but the role of air travel in the movement of vector-borne diseases is less well understood. Increasingly however, wider reaching surveillance for vector-borne diseases and our improving abilities to map the distributions of vectors and the diseases they carry, are providing opportunities to better our understanding of the impact of increasing air travel. Here we examine global trends in the continued expansion of air transport and its impact upon epidemiology. Novel malaria and chikungunya examples are presented, detailing how geospatial data in combination with information on air traffic can be used to predict the risks of vector-borne disease importation and establishment. Finally, we describe the development of an online tool, the Vector-Borne Disease Airline Importation Risk (VBD-Air) tool, which brings together spatial data on air traffic and vector-borne disease distributions to quantify the seasonally changing risks for importation to non-endemic regions. Such a framework provides the first steps towards an ultimate goal of adaptive management based on near real time flight data and vector-borne disease surveillance.

  1. Genetic manipulation of endosymbionts to control vector and vector borne diseases

    Directory of Open Access Journals (Sweden)

    Jay Prakash Gupta

    Full Text Available Vector borne diseases (VBD are on the rise because of failure of the existing methods of control of vector and vector borne diseases and the climate change. A steep rise of VBDs are due to several factors like selection of insecticide resistant vector population, drug resistant parasite population and lack of effective vaccines against the VBDs. Environmental pollution, public health hazard and insecticide resistant vector population indicate that the insecticides are no longer a sustainable control method of vector and vector-borne diseases. Amongst the various alternative control strategies, symbiont based approach utilizing endosymbionts of arthropod vectors could be explored to control the vector and vector borne diseases. The endosymbiont population of arthropod vectors could be exploited in different ways viz., as a chemotherapeutic target, vaccine target for the control of vectors. Expression of molecules with antiparasitic activity by genetically transformed symbiotic bacteria of disease-transmitting arthropods may serve as a powerful approach to control certain arthropod-borne diseases. Genetic transformation of symbiotic bacteria of the arthropod vector to alter the vector’s ability to transmit pathogen is an alternative means of blocking the transmission of VBDs. In Indian scenario, where dengue, chikungunya, malaria and filariosis are prevalent, paratransgenic based approach can be used effectively. [Vet World 2012; 5(9.000: 571-576

  2. Vector independent transmission of the vector-borne bluetongue virus.

    Science.gov (United States)

    van der Sluijs, Mirjam Tineke Willemijn; de Smit, Abraham J; Moormann, Rob J M

    2016-01-01

    Bluetongue is an economically important disease of ruminants. The causative agent, Bluetongue virus (BTV), is mainly transmitted by insect vectors. This review focuses on vector-free BTV transmission, and its epizootic and economic consequences. Vector-free transmission can either be vertical, from dam to fetus, or horizontal via direct contract. For several BTV-serotypes, vertical (transplacental) transmission has been described, resulting in severe congenital malformations. Transplacental transmission had been mainly associated with live vaccine strains. Yet, the European BTV-8 strain demonstrated a high incidence of transplacental transmission in natural circumstances. The relevance of transplacental transmission for the epizootiology is considered limited, especially in enzootic areas. However, transplacental transmission can have a substantial economic impact due to the loss of progeny. Inactivated vaccines have demonstrated to prevent transplacental transmission. Vector-free horizontal transmission has also been demonstrated. Since direct horizontal transmission requires close contact of animals, it is considered only relevant for within-farm spreading of BTV. The genetic determinants which enable vector-free transmission are present in virus strains circulating in the field. More research into the genetic changes which enable vector-free transmission is essential to better evaluate the risks associated with outbreaks of new BTV serotypes and to design more appropriate control measures.

  3. Effects of Climate and Climate Change on Vectors and Vector-Borne Diseases: Ticks Are Different.

    Science.gov (United States)

    Ogden, Nick H; Lindsay, L Robbin

    2016-08-01

    There has been considerable debate as to whether global risk from vector-borne diseases will be impacted by climate change. This has focussed on important mosquito-borne diseases that are transmitted by the vectors from infected to uninfected humans. However, this debate has mostly ignored the biological diversity of vectors and vector-borne diseases. Here, we review how climate and climate change may impact those most divergent of arthropod disease vector groups: multivoltine insects and hard-bodied (ixodid) ticks. We contrast features of the life cycles and behaviour of these arthropods, and how weather, climate, and climate change may have very different impacts on the spatiotemporal occurrence and abundance of vectors, and the pathogens they transmit. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  4. Rapid Identification of Vector-Borne Flaviviruses by Mass Spectrometry

    Science.gov (United States)

    2010-02-01

    Eastern, and Siberian subtypes [9]. Several tick-borne flaviviruses can also cause hemorrhagic disease. Important examples of these viruses include...assay. Identical base compositions within a column are the same color. Unique base compositions are shown with white backgrounds. (For interpretation...States, 1999e2005. Vector Borne Zoonotic Dis 2008;8:733e40. [18] Hofstadler SA, Sampath R, Blyn LB, Eshoo MW, Hall TA, Jiang Y, et al. TIGER : the

  5. Urbanization, land tenure security and vector-borne Chagas disease

    Science.gov (United States)

    Levy, Michael Z.; Barbu, Corentin M.; Castillo-Neyra, Ricardo; Quispe-Machaca, Victor R.; Ancca-Juarez, Jenny; Escalante-Mejia, Patricia; Borrini-Mayori, Katty; Niemierko, Malwina; Mabud, Tarub S.; Behrman, Jere R.; Naquira-Velarde, Cesar

    2014-01-01

    Modern cities represent one of the fastest growing ecosystems on the planet. Urbanization occurs in stages; each stage characterized by a distinct habitat that may be more or less susceptible to the establishment of disease vector populations and the transmission of vector-borne pathogens. We performed longitudinal entomological and epidemiological surveys in households along a 1900 × 125 m transect of Arequipa, Peru, a major city of nearly one million inhabitants, in which the transmission of Trypanosoma cruzi, the aetiological agent of Chagas disease, by the insect vector Triatoma infestans, is an ongoing problem. The transect spans a cline of urban development from established communities to land invasions. We find that the vector is tracking the development of the city, and the parasite, in turn, is tracking the dispersal of the vector. New urbanizations are free of vector infestation for decades. T. cruzi transmission is very recent and concentrated in more established communities. The increase in land tenure security during the course of urbanization, if not accompanied by reasonable and enforceable zoning codes, initiates an influx of construction materials, people and animals that creates fertile conditions for epidemics of some vector-borne diseases. PMID:24990681

  6. Major vectors and vector-borne diseases in small ruminants in Ethiopia: A systematic review.

    Science.gov (United States)

    Asmare, Kassahun; Abayneh, Takele; Sibhat, Berhanu; Shiferaw, Dessie; Szonyi, Barbara; Krontveit, Randi I; Skjerve, Eystein; Wieland, Barbara

    2017-06-01

    Vector-borne diseases are among major health constraints of small ruminant in Ethiopia. While various studies on single vector-borne diseases or presence of vectors have been conducted, no summarized evidence is available on the occurrence of these diseases and the related vectors. This systematic literature review provides a comprehensive summary on major vectors and vector-borne diseases in small ruminants in Ethiopia. Search for published and unpublished literature was conducted between 8th of January and 25th of June 2015. The search was both manual and electronic. The databases used in electronic search were PubMed, Web of Science, CAB Direct and AJOL. For most of the vector-borne diseases, the summary was limited to narrative synthesis due to lack of sufficient data. Meta-analysis was computed for trypanosomosis and dermatophilosis while meta-regression and sensitivity analysis was done only for trypanososmosis due to lack of sufficient reports on dermatophilosis. Owing emphasis to their vector role, ticks and flies were summarized narratively at genera/species level. In line with inclusion criteria, out of 106 initially identified research reports 43 peer-reviewed articles passed the quality assessment. Data on 7 vector-borne diseases were extracted at species and region level from each source. Accordingly, the pooled prevalence estimate of trypanosomosis was 3.7% with 95% confidence interval (CI) 2.8, 4.9), while that of dermatophilosis was 3.1% (95% CI: 1.6, 6.0). The in-between study variance noted for trypanosomosis was statistically significant (pparasitic presence in blood was documented for babesiosis (3.7% in goats); and anaplasmosis (3.9% in sheep). Serological evidence was retrieved for bluetongue ranging from 34.1% to 46.67% in sheep, and coxiellosis was 10.4% in goats. There was also molecular evidence on the presence of theileriosis in sheep (93%, n=160) and goats (1.9%, n=265). Regarding vectors of veterinary importance, 14 species of ticks in

  7. Reducing vector-borne disease by empowering farmers in integrated vector management

    NARCIS (Netherlands)

    Berg, van den H.; Hildebrand, von A.; Ragunathan, V.; Das, P.K.

    2007-01-01

    PROBLEM: Irrigated agriculture exposes rural people to health risks associated with vector-borne diseases and pesticides used in agriculture and for public health protection. Most developing countries lack collaboration between the agricultural and health sectors to jointly address these problems.

  8. Integrating Transgenic Vector Manipulation with Clinical Interventions to Manage Vector-Borne Diseases.

    Directory of Open Access Journals (Sweden)

    Kenichi W Okamoto

    2016-03-01

    Full Text Available Many vector-borne diseases lack effective vaccines and medications, and the limitations of traditional vector control have inspired novel approaches based on using genetic engineering to manipulate vector populations and thereby reduce transmission. Yet both the short- and long-term epidemiological effects of these transgenic strategies are highly uncertain. If neither vaccines, medications, nor transgenic strategies can by themselves suffice for managing vector-borne diseases, integrating these approaches becomes key. Here we develop a framework to evaluate how clinical interventions (i.e., vaccination and medication can be integrated with transgenic vector manipulation strategies to prevent disease invasion and reduce disease incidence. We show that the ability of clinical interventions to accelerate disease suppression can depend on the nature of the transgenic manipulation deployed (e.g., whether vector population reduction or replacement is attempted. We find that making a specific, individual strategy highly effective may not be necessary for attaining public-health objectives, provided suitable combinations can be adopted. However, we show how combining only partially effective antimicrobial drugs or vaccination with transgenic vector manipulations that merely temporarily lower vector competence can amplify disease resurgence following transient suppression. Thus, transgenic vector manipulation that cannot be sustained can have adverse consequences-consequences which ineffective clinical interventions can at best only mitigate, and at worst temporarily exacerbate. This result, which arises from differences between the time scale on which the interventions affect disease dynamics and the time scale of host population dynamics, highlights the importance of accounting for the potential delay in the effects of deploying public health strategies on long-term disease incidence. We find that for systems at the disease-endemic equilibrium, even

  9. Broad patterns in domestic vector-borne Trypanosoma cruzi transmission dynamics: synanthropic animals and vector control.

    Science.gov (United States)

    Peterson, Jennifer K; Bartsch, Sarah M; Lee, Bruce Y; Dobson, Andrew P

    2015-10-22

    Chagas disease (caused by Trypanosoma cruzi) is the most important neglected tropical disease (NTD) in Latin America, infecting an estimated 5.7 million people in the 21 countries where it is endemic. It is one of the NTDs targeted for control and elimination by the 2020 London Declaration goals, with the first goal being to interrupt intra-domiciliary vector-borne T. cruzi transmission. A key question in domestic T. cruzi transmission is the role that synanthropic animals play in T. cruzi transmission to humans. Here, we ask, (1) do synanthropic animals need to be targeted in Chagas disease prevention policies?, and (2) how does the presence of animals affect the efficacy of vector control? We developed a simple mathematical model to simulate domestic vector-borne T. cruzi transmission and to specifically examine the interaction between the presence of synanthropic animals and effects of vector control. We used the model to explore how the interactions between triatomine bugs, humans and animals impact the number and proportion of T. cruzi-infected bugs and humans. We then examined how T. cruzi dynamics change when control measures targeting vector abundance are introduced into the system. We found that the presence of synanthropic animals slows the speed of T. cruzi transmission to humans, and increases the sensitivity of T. cruzi transmission dynamics to vector control measures at comparable triatomine carrying capacities. However, T. cruzi transmission is amplified when triatomine carrying capacity increases with the abundance of syntathoropic hosts. Our results suggest that in domestic T. cruzi transmission scenarios where no vector control measures are in place, a reduction in synanthropic animals may slow T. cruzi transmission to humans, but it would not completely eliminate transmission. To reach the 2020 goal of interrupting intra-domiciliary T. cruzi transmission, it is critical to target vector populations. Additionally, where vector control measures

  10. Vector-borne diseases: the basic reproduction number R0 and risk maps

    NARCIS (Netherlands)

    Hartemink, N.A.|info:eu-repo/dai/nl/304836699

    2009-01-01

    This thesis deals with the derivation of the basic reproduction number (R0) for vector-borne diseases, in the context of studying the effect of climate change on the risk of emergence diseases. Vector-borne diseases are transmitted from an infected individual to another individual by vectors,

  11. Vector-borne disease risk indexes in spatially structured populations.

    Directory of Open Access Journals (Sweden)

    Jorge Velázquez-Castro

    2018-02-01

    Full Text Available There are economic and physical limitations when applying prevention and control strategies for urban vector borne diseases. Consequently, there are increasing concerns and interest in designing efficient strategies and regulations that health agencies can follow in order to reduce the imminent impact of viruses like Dengue, Zika and Chikungunya. That includes fumigation, abatization, reducing the hatcheries, picking up trash, information campaigns. A basic question that arise when designing control strategies is about which and where these ones should focus. In other words, one would like to know whether preventing the contagion or decrease vector population, and in which area of the city, is more efficient. In this work, we propose risk indexes based on the idea of secondary cases from patch to patch. Thus, they take into account human mobility and indicate which patch has more chance to be a corridor for the spread of the disease and which is more vulnerable, i.e. more likely to have cases?. They can also indicate the neighborhood where hatchery control will reduce more the number of potential cases. In order to illustrate the usefulness of these indexes, we run a set of numerical simulations in a mathematical model that takes into account the urban mobility and the differences in population density among the areas of a city. If we label by i a particular neighborhood, the transmission risk index (TRi measures the potential secondary cases caused by a host in that neighborhood. The vector transmission risk index (VTRi measures the potential secondary cases caused by a vector. Finally, the vulnerability risk index (VRi measures the potential secondary cases in the neighborhood. Transmission indexes can be used to give geographical priority to some neighborhoods when applying prevention and control measures. On the other hand, the vulnerability index can be useful to implement monitoring campaigns or public health investment.

  12. Assessment of Climate Change and Vector-borne Diseases in the United States

    Science.gov (United States)

    Monaghan, A. J.; Beard, C. B.; Eisen, R. J.; Barker, C. M.; Garofalo, J.; Hahn, M.; Hayden, M.; Ogden, N.; Schramm, P.

    2016-12-01

    Vector-borne diseases are illnesses that are transmitted by vectors, which include mosquitoes, ticks, and fleas. The seasonality, distribution, and prevalence of vector-borne diseases are influenced significantly by climate factors, primarily high and low temperature extremes and precipitation patterns. In this presentation we summarize key findings from Chapter 5 ("Vector-borne Diseases") of the recently published USGCRP Scientific Assessment of the Impacts of Climate Change on Human Health in the United States. Climate change is expected to alter geographic and seasonal distributions of vectors and vector-borne diseases, leading to earlier activity and northward range expansion of ticks capable of carrying the bacteria that cause Lyme disease and other pathogens, and influencing the distribution, abundance and prevalence of infection in mosquitoes that transmit West Nile virus and other pathogens. The emergence or reemergence of vector-borne pathogens is also likely.

  13. Geographic range of vector-borne infections and their vectors: the role of African wildlife.

    Science.gov (United States)

    van Vuuren, M; Penzhorn, B L

    2015-04-01

    The role of African wildlife in the occurrence of vector-borne infections in domestic animals has gained renewed interest as emerging and re-emerging infections occur worldwide at an increasing rate. In Africa, biodiversity conservation and the expansion of livestock production have increased the risk of transmitting vector-borne infections between wildlife and livestock. The indigenous African pathogens with transboundary potential, such as Rift Valley fever virus, African horse sickness virus, bluetongue virus, lumpy skin disease virus, African swine fever virus, and blood-borne parasites have received the most attention. There is no evidence for persistent vector-borne viral infections in African wildlife. For some viral infections, wildlife may act as a reservoir through the inter-epidemic circulation of viruses with mild or subclinical manifestations. Wildlife may also act as introductory or transporting hosts when moved to new regions, e.g. for lumpy skin disease virus, Rift Valley fever virus and West Nile virus. Wildlife may also act as amplifying hosts when exposed to viruses in the early part of the warm season when vectors are active, with spillover to domestic animals later in the season, e.g. with bluetongue and African horse sickness. Some tick species found on domestic animals are more abundant on wildlife hosts; some depend on wildlife hosts to complete their life cycle. Since the endemic stability of a disease depends on a sufficiently large tick population to ensure that domestic animals become infected at an early age, the presence of wildlife hosts that augment tick numbers may be beneficial. Many wild ungulate species are reservoirs of Anaplasma spp., while the role of wildlife in the epidemiology of heartwater (Ehrlichia ruminantium infection) has not been elucidated. Wild ungulates are not usually reservoirs of piroplasms that affect livestock; however, there are two exceptions: zebra, which are reservoirs of Babesia caballi and Theileria

  14. Borrelia miyamotoi, Other Vector-Borne Agents in Cat Blood and Ticks in Eastern Maryland.

    Science.gov (United States)

    Shannon, Avery B; Rucinsky, Renee; Gaff, Holly D; Brinkerhoff, R Jory

    2017-12-01

    We collected blood and tick samples in eastern Maryland to quantify vector-borne pathogen exposure and infection in healthy cats and to assess occupational disease risk to veterinary professionals and others who regularly interact with household pets. Thirty-six percent of healthy cats parasitized by ticks at time of examination (9/25) were exposed to, and 14% of bloods (7/49) tested PCR-positive for, at least one vector-borne pathogen including several bloods and ticks with Borrelia miyamotoi, a recently recognized tick-borne zoonotic bacterium. There was no indication that high tick burdens were associated with exposure to vector-borne pathogens. Our results underscore the potential importance of cats to human vector-borne disease risk.

  15. The standardised freight container: vector of vectors and vector-borne diseases.

    Science.gov (United States)

    Reiter, P

    2010-04-01

    The standardised freight container was one of the most important innovations of the 20th Century. Containerised cargoes travel from their point of origin to their destination by ship, road and rail as part of a single journey, without unpacking. This simple concept is the key element in cheap, rapid transport by land and sea, and has led to a phenomenal growth in global trade. Likewise, containerised air cargo has led to a remarkable increase in the inter-continental transportation of goods, particularly perishable items such as flowers, fresh vegetables and live animals. In both cases, containerisation offers great advantages in speed and security, but reduces the opportunity to inspect cargoes in transit. An inevitable consequence is the globalisation of undesirable species of animals, plants and pathogens. Moreover, cheap passenger flights offer worldwide travel for viral and parasitic pathogens in infected humans. The continued emergence of exotic pests, vectors and pathogens throughout the world is an unavoidable consequence of these advances in transportation technology.

  16. Vector-borne disease intelligence: strategies to deal with disease burden and threats

    Czech Academy of Sciences Publication Activity Database

    Braks, M.; Medlock, J. M.; Hubálek, Zdeněk; Hjertqvist, M.; Perrin, Y.; Lancelot, R.; Duchyene, E.; Hendrickx, G.; Stroo, A.; Heyman, P.; Sprong, H.

    2014-01-01

    Roč. 2, č. 280 (2014), s. 280 ISSN 2296-2565 Institutional support: RVO:68081766 Keywords : disease burden * emerging diseases * one health * surveillance * threat * vector-borne diseases Subject RIV: EE - Microbiology, Virology

  17. Ocular dirofilariasis: Ophthalmic implication of climate change on vector-borne parasites

    Directory of Open Access Journals (Sweden)

    Joseph D. Boss, M.D.

    2017-09-01

    Conclusions and importance: With increasing global temperatures, ocular dirofilariasis is being introduced in more northern climates and should be included in the differential diagnosis in areas previously isolated from these vector-borne parasites.

  18. Web-based GIS: the vector-borne disease airline importation risk (VBD-AIR) tool.

    Science.gov (United States)

    Huang, Zhuojie; Das, Anirrudha; Qiu, Youliang; Tatem, Andrew J

    2012-08-14

    Over the past century, the size and complexity of the air travel network has increased dramatically. Nowadays, there are 29.6 million scheduled flights per year and around 2.7 billion passengers are transported annually. The rapid expansion of the network increasingly connects regions of endemic vector-borne disease with the rest of the world, resulting in challenges to health systems worldwide in terms of vector-borne pathogen importation and disease vector invasion events. Here we describe the development of a user-friendly Web-based GIS tool: the Vector-Borne Disease Airline Importation Risk Tool (VBD-AIR), to help better define the roles of airports and airlines in the transmission and spread of vector-borne diseases. Spatial datasets on modeled global disease and vector distributions, as well as climatic and air network traffic data were assembled. These were combined to derive relative risk metrics via air travel for imported infections, imported vectors and onward transmission, and incorporated into a three-tier server architecture in a Model-View-Controller framework with distributed GIS components. A user-friendly web-portal was built that enables dynamic querying of the spatial databases to provide relevant information. The VBD-AIR tool constructed enables the user to explore the interrelationships among modeled global distributions of vector-borne infectious diseases (malaria. dengue, yellow fever and chikungunya) and international air service routes to quantify seasonally changing risks of vector and vector-borne disease importation and spread by air travel, forming an evidence base to help plan mitigation strategies. The VBD-AIR tool is available at http://www.vbd-air.com. VBD-AIR supports a data flow that generates analytical results from disparate but complementary datasets into an organized cartographical presentation on a web map for the assessment of vector-borne disease movements on the air travel network. The framework built provides a flexible

  19. Climate change and vector-borne diseases of public health significance.

    Science.gov (United States)

    Ogden, Nicholas H

    2017-10-16

    There has been much debate as to whether or not climate change will have, or has had, any significant effect on risk from vector-borne diseases. The debate on the former has focused on the degree to which occurrence and levels of risk of vector-borne diseases are determined by climate-dependent or independent factors, while the debate on the latter has focused on whether changes in disease incidence are due to climate at all, and/or are attributable to recent climate change. Here I review possible effects of climate change on vector-borne diseases, methods used to predict these effects and the evidence to date of changes in vector-borne disease risks that can be attributed to recent climate change. Predictions have both over- and underestimated the effects of climate change. Mostly under-estimations of effects are due to a focus only on direct effects of climate on disease ecology while more distal effects on society's capacity to control and prevent vector-borne disease are ignored. There is increasing evidence for possible impacts of recent climate change on some vector-borne diseases but for the most part, observed data series are too short (or non-existent), and impacts of climate-independent factors too great, to confidently attribute changing risk to climate change. © Crown copyright 2017.

  20. Major emerging vector-borne zoonotic diseases of public health importance in Canada.

    Science.gov (United States)

    Kulkarni, Manisha A; Berrang-Ford, Lea; Buck, Peter A; Drebot, Michael A; Lindsay, L Robbin; Ogden, Nicholas H

    2015-06-10

    In Canada, the emergence of vector-borne diseases may occur via international movement and subsequent establishment of vectors and pathogens, or via northward spread from endemic areas in the USA. Re-emergence of endemic vector-borne diseases may occur due to climate-driven changes to their geographic range and ecology. Lyme disease, West Nile virus (WNV), and other vector-borne diseases were identified as priority emerging non-enteric zoonoses in Canada in a prioritization exercise conducted by public health stakeholders in 2013. We review and present the state of knowledge on the public health importance of these high priority emerging vector-borne diseases in Canada. Lyme disease is emerging in Canada due to range expansion of the tick vector, which also signals concern for the emergence of human granulocytic anaplasmosis, babesiosis, and Powassan virus. WNV has been established in Canada since 2001, with epidemics of varying intensity in following years linked to climatic drivers. Eastern equine encephalitis virus, Jamestown Canyon virus, snowshoe hare virus, and Cache Valley virus are other mosquito-borne viruses endemic to Canada with the potential for human health impact. Increased surveillance for emerging pathogens and vectors and coordinated efforts among sectors and jurisdictions will aid in early detection and timely public health response.

  1. Neglected vector-borne zoonoses in Europe: Into the wild.

    NARCIS (Netherlands)

    Tomassone, Laura; Berriatua, Eduardo; De Sousa, Rita; Duscher, Gerhard Georg; Mihalca, Andrei Daniel; Silaghi, Cornelia; Sprong, Hein; Zintl, Annetta

    2018-01-01

    Wild vertebrates are involved in the transmission cycles of numerous pathogens. Additionally, they can affect the abundance of arthropod vectors. Urbanization, landscape and climate changes, and the adaptation of vectors and wildlife to human habitats represent complex and evolving scenarios, which

  2. Possible impact of rising sea levels on vector-borne infectious diseases

    Directory of Open Access Journals (Sweden)

    Surendran Sinnathamby N

    2011-01-01

    Full Text Available Abstract Background Vector-borne infectious diseases are a significant cause of human and animal mortality and morbidity. Modeling studies predict that changes in climate that accompany global warming will alter the transmission risk of many vector-borne infectious diseases in different parts of the world. Global warming will also raise sea levels, which will lead to an increase in saline and brackish water bodies in coastal areas. The potential impact of rising sea levels, as opposed to climate change, on the prevalence of vector-borne infectious diseases has hitherto been unrecognised. Presentation of the hypothesis Mosquito species possessing salinity-tolerant larvae and pupae, and capable of transmitting arboviruses and parasites are found in many parts of the world. An expansion of brackish and saline water bodies in coastal areas, associated with rising sea levels, can increase densities of salinity-tolerant vector mosquitoes and lead to the adaptation of freshwater vectors to breed in brackish and saline waters. The breeding of non-mosquito vectors may also be influenced by salinity changes in coastal habitats. Higher vector densities can increase transmission of vector-borne infectious diseases in coastal localities, which can then spread to other areas. Testing the hypothesis The demonstration of increases in vector populations and disease prevalence that is related to an expansion of brackish/saline water bodies in coastal areas will provide the necessary supportive evidence. However the implementation of specific vector and disease control measures to counter the threat will confound the expected findings. Implications of the hypothesis Rising sea levels can act synergistically with climate change and then interact in a complex manner with other environmental and socio-economic factors to generate a greater potential for the transmission of vector-borne infectious diseases. The resulting health impacts are likely to be particularly

  3. Surveillance of arthropod vector-borne infectious diseases using remote sensing techniques: a review.

    Directory of Open Access Journals (Sweden)

    Satya Kalluri

    2007-10-01

    Full Text Available Epidemiologists are adopting new remote sensing techniques to study a variety of vector-borne diseases. Associations between satellite-derived environmental variables such as temperature, humidity, and land cover type and vector density are used to identify and characterize vector habitats. The convergence of factors such as the availability of multi-temporal satellite data and georeferenced epidemiological data, collaboration between remote sensing scientists and biologists, and the availability of sophisticated, statistical geographic information system and image processing algorithms in a desktop environment creates a fertile research environment. The use of remote sensing techniques to map vector-borne diseases has evolved significantly over the past 25 years. In this paper, we review the status of remote sensing studies of arthropod vector-borne diseases due to mosquitoes, ticks, blackflies, tsetse flies, and sandflies, which are responsible for the majority of vector-borne diseases in the world. Examples of simple image classification techniques that associate land use and land cover types with vector habitats, as well as complex statistical models that link satellite-derived multi-temporal meteorological observations with vector biology and abundance, are discussed here. Future improvements in remote sensing applications in epidemiology are also discussed.

  4. Vector-borne disease intelligence: Strategies to deal with disease burden and threats

    Directory of Open Access Journals (Sweden)

    Marieta eBraks

    2014-12-01

    Full Text Available Owing to the complex nature of vector-borne diseases, whereby monitoring of human case patients does not suffice, public health authorities experience challenges in surveillance and control of vector-borne diseases. Knowledge on the presence and distribution of vectors and the pathogens they transmit is vital to a risk assessment process to permit effective early warning, surveillance and control of vector-borne diseases. Upon accepting this reality, public health authorities face the phenomenon of an exponential rise in the number of possible surveillance targets and how to decide which are essential. Here, . we propose a comprehensive approach that integrates three surveillance strategies: population-based surveillance, disease-based surveillance and context-based surveillance for EU member states to tailor the best surveillance strategy for control of vector-borne diseases in their geographic region. By classifying the surveillance structure into 5 different contexts, we hope to provide guidance in optimizing surveillance efforts. Contextual surveillance strategies for vector-borne diseases entail combining organization and data collection approaches that result in disease intelligence rather than a preset static structure.

  5. Drivers for the emergence and re-emergence of vector-borne protozoal and bacterial diseases.

    Science.gov (United States)

    Harrus, S; Baneth, G

    2005-10-01

    In recent years, vector-borne parasitic and bacterial diseases have emerged or re-emerged in many geographical regions causing global health and economic problems that involve humans, livestock, companion animals and wild life. The ecology and epidemiology of vector-borne diseases are affected by the interrelations between three major factors comprising the pathogen, the host (human, animal or vector) and the environment. Important drivers for the emergence and spread of vector-borne parasites include habitat changes, alterations in water storage and irrigation habits, atmospheric and climate changes, immunosuppression by HIV, pollution, development of insecticide and drug resistance, globalization and the significant increase in international trade, tourism and travel. War and civil unrest, and governmental or global management failure are also major contributors to the spread of infectious diseases. The improvement of epidemic understanding and planning together with the development of new diagnostic molecular techniques in the last few decades have allowed researchers to better diagnose and trace pathogens, their origin and routes of infection, and to develop preventive public health and intervention programs. Health care workers, physicians, veterinarians and biosecurity officers should play a key role in future prevention of vector-borne diseases. A coordinated global approach for the prevention of vector-borne diseases should be implemented by international organizations and governmental agencies in collaboration with research institutions.

  6. PCR evaluation of selected vector-borne pathogens in dogs with pericardial effusion.

    Science.gov (United States)

    Tabar, M-D; Movilla, R; Serrano, L; Altet, L; Francino, O; Roura, X

    2018-04-01

    To investigate evidence for selected vector-borne pathogen infections in dogs with pericardial effusion living in a Mediterranean area in which several canine vector-borne diseases are endemic. Archived EDTA blood (n=68) and pericardial fluid samples (n=58) from dogs with pericardial effusion (n=68) were included. Dogs without pericardial effusion examined for other reasons were included as controls (n=60). Pericardial effusion was classified as neoplastic in 40 dogs, idiopathic in 23 dogs and of unknown aetiology in 5 dogs. Real-time PCR was performed for Leishmania infantum, Ehrlichia/Anaplasma species, Hepatozoon canis, Babesia species, Rickettsia species and Bartonella species, and sequencing of PCR products from positive samples was used to confirm species specificity. Vector-borne pathogens were found in 18 dogs: 16 of 68 dogs with pericardial effusion (23·5%) and two of 60 control dogs (3·3%). Positive dogs demonstrated DNA of Leishmania infantum (n=7), Anaplasma platys (n=2, one dog coinfected with Leishmania infantum), Babesia canis (n=5), Babesia gibsoni (n=3) and Hepatozoon canis (n=2). Vector-borne pathogens were more commonly detected among dogs with pericardial effusion than controls (P=0·001). There was no relationship between aetiology of the pericardial effusion and evidence of vector-borne pathogens (P=0·932). Vector-borne pathogens are often detected in dogs with pericardial effusion and require further investigation, especially in dogs with idiopathic pericardial effusion. PCR can provide additional information about the potential role of vector-borne pathogens in dogs with pericardial effusion living in endemic areas. © 2018 British Small Animal Veterinary Association.

  7. Predators indirectly control vector-borne disease: linking predator-prey and host-pathogen models.

    Science.gov (United States)

    Moore, Sean M; Borer, Elizabeth T; Hosseini, Parviez R

    2010-01-06

    Pathogens transmitted by arthropod vectors are common in human populations, agricultural systems and natural communities. Transmission of these vector-borne pathogens depends on the population dynamics of the vector species as well as its interactions with other species within the community. In particular, predation may be sufficient to control pathogen prevalence indirectly via the vector. To examine the indirect effect of predators on vectored-pathogen dynamics, we developed a theoretical model that integrates predator-prey and host-pathogen theory. We used this model to determine whether predation can prevent pathogen persistence or alter the stability of host-pathogen dynamics. We found that, in the absence of predation, pathogen prevalence in the host increases with vector fecundity, whereas predation on the vector causes pathogen prevalence to decline, or even become extinct, with increasing vector fecundity. We also found that predation on a vector may drastically slow the initial spread of a pathogen. The predator can increase host abundance indirectly by reducing or eliminating infection in the host population. These results highlight the importance of studying interactions that, within the greater community, may alter our predictions when studying disease dynamics. From an applied perspective, these results also suggest situations where an introduced predator or the natural enemies of a vector may slow the rate of spread of an emerging vector-borne pathogen.

  8. Optimal vaccination scenarios against vector-borne diseases

    DEFF Research Database (Denmark)

    Græsbøll, Kaare; Enøe, Claes; Bødker, Rene

    that would increase distance between infectious and susceptible hosts. This can be done very efficiently on a regional scale if the incursion route is well specified. However as the long-range spread of midge borne disease is still poorly quantified, more robust national vaccination schemes seems preferable...

  9. Global climate change and vector-borne diseases

    Science.gov (United States)

    Ginsberg, H.S.

    2002-01-01

    Global warming will have different effects on different diseases because of the complex and idiosynchratic interactions between vectors, hosts, and pathogens that influence transmission dynamics of each pathogen. Human activities, including urbanization, rapid global travel, and vector management, have profound effects on disease transmission that can operate on more rapid time scales than does global climate change. The general concern about global warming encouraging the spread of tropical diseases is legitimate, but the effects vary among diseases, and the ecological implications are difficult to predict.

  10. Spatial analysis of vector-borne infectious diseases and ecological indicators using GIS and remote sensing

    Science.gov (United States)

    Anh, N. K.; Liou, Y. A.

    2017-12-01

    Ecological and climate indicators play a vital role in defining patterns of human activities and behaviors, such as seasonal features, migration, winter-summer lifestyles, which in turn might be associated with vector-borne disease habitats and transmission risks. Remote sensing has been instrumental in deriving environmental variables and indicators. GIS is shown to be a powerful tool in spatiotemporal visualization and distribution of vector-borne diseases and for analysis of associations between environmental conditions and characteristics of vector-borne habitats. Vietnam is in the sub-tropical climate zone with high humidity and abundant precipitation, while the distribution of precipitation is uneven leading to frequently annual occurrence of drought and flood disasters. Moreover, urban heat island effect is significantly enhanced in urbanized areas in recent years. The increase in the frequency and magnitude of severity of weather extremes that are potentially linked to climate change and anthropogenic processes have highlighted the demand of research into health risk assessment and adaptive capacity. This research focuses on the analysis of physical features of environmental indicators and its association with vector-borne diseases as well as adaptive capacity. The study illustrates how remotely sensed data has been utilized in geohealth applications, surveillance, and health risk mapping. In addition, promising possibilities of allowing disease early-warning systems with citizen participation platform will be proposed. Keywords: Vector-borne diseases; environmental indicators; remote sensing; GIS; Vietnam.

  11. Optimal vaccination strategies against vector-borne diseases

    DEFF Research Database (Denmark)

    Græsbøll, Kaare; Enøe, Claes; Bødker, Rene

    2014-01-01

    Using a process oriented semi-agent based model, we simulated the spread of Bluetongue virus by Culicoides, biting midges, between cattle in Denmark. We evaluated the minimum vaccination cover and minimum cost for eight different preventive vaccination strategies in Denmark. The simulation model ...... results when index cases were in the vaccinated areas. However, given that the long-range spread of midge borne disease is still poorly quantified, more robust national vaccination schemes seem preferable....

  12. Arthropod Innate Immune Systems and Vector-Borne Diseases

    OpenAIRE

    Baxter, Richard H. G.; Contet, Alicia; Krueger, Kathryn

    2017-01-01

    Arthropods, especially ticks and mosquitoes, are the vectors for a number of parasitic and viral human diseases, including malaria, sleeping sickness, Dengue, and Zika, yet arthropods show tremendous individual variation in their capacity to transmit disease. A key factor in this capacity is the group of genetically encoded immune factors that counteract infection by the pathogen. Arthropod-specific pattern recognition receptors and protease cascades detect and respond to infection. Proteins ...

  13. Canine and feline vector-borne diseases in Italy: current situation and perspectives

    Directory of Open Access Journals (Sweden)

    Dantas-Torres Filipe

    2010-01-01

    Full Text Available Abstract In Italy, dogs and cats are at risk of becoming infected by different vector-borne pathogens, including protozoa, bacteria, and helminths. Ticks, fleas, phlebotomine sand flies, and mosquitoes are recognized vectors of pathogens affecting cats and dogs, some of which (e.g., Anaplasma phagocytophilum, Borrelia burgdorferi, Dipylidium caninum, Leishmania infantum, Dirofilaria immitis, and Dirofilaria repens are of zoonotic concern. Recent studies have highlighted the potential of fleas as vectors of pathogens of zoonotic relevance (e.g., Rickettsia felis in this country. While some arthropod vectors (e.g., ticks and fleas are present in certain Italian regions throughout the year, others (e.g., phlebotomine sand flies are most active during the summer season. Accordingly, control strategies, such as those relying on the systematic use of acaricides and insecticides, should be planned on the basis of the ecology of both vectors and pathogens in different geographical areas in order to improve their effectiveness in reducing the risk of infection by vector-borne pathogens. This article reviews the current situation and perspectives of canine and feline vector-borne diseases in Italy.

  14. Modelling spread of Bluetongue and other vector borne diseases in Denmark and evaluation of intervention strategies

    DEFF Research Database (Denmark)

    Græsbøll, Kaare

    that describes spread of disease using vectors or hosts as agents of the spread. The model is run with bluetongue as the primary case study, and it is demonstrated how an epidemic outbreak of bluetongue 8 in Denmark is sensitive to the use of pasture, climate, vaccination, vector abundance, and flying parameters......The main outcome of this PhD project is a generic model for non-contagious infectious vector-borne disease spread by one vector species between up to two species of hosts distributed on farms and pasture. The model features a within-herd model of disease, combined with a triple movement kernel....... In constructing a more process oriented agent-based approach to spread modeling new parameters describing vector behavior were introduced. When these vector flying parameters have been quantified by experiments, this model can be implemented on areas naïve to the modeled disease with a high predictive power...

  15. Arthropod Innate Immune Systems and Vector-Borne Diseases.

    Science.gov (United States)

    Baxter, Richard H G; Contet, Alicia; Krueger, Kathryn

    2017-02-21

    Arthropods, especially ticks and mosquitoes, are the vectors for a number of parasitic and viral human diseases, including malaria, sleeping sickness, Dengue, and Zika, yet arthropods show tremendous individual variation in their capacity to transmit disease. A key factor in this capacity is the group of genetically encoded immune factors that counteract infection by the pathogen. Arthropod-specific pattern recognition receptors and protease cascades detect and respond to infection. Proteins such as antimicrobial peptides, thioester-containing proteins, and transglutaminases effect responses such as lysis, phagocytosis, melanization, and agglutination. Effector responses are initiated by damage signals such as reactive oxygen species signaling from epithelial cells and recognized by cell surface receptors on hemocytes. Antiviral immunity is primarily mediated by siRNA pathways but coupled with interferon-like signaling, antimicrobial peptides, and thioester-containing proteins. Molecular mechanisms of immunity are closely linked to related traits of longevity and fertility, and arthropods have the capacity for innate immunological memory. Advances in understanding vector immunity can be leveraged to develop novel control strategies for reducing the rate of transmission of both ancient and emerging threats to global health.

  16. Regulation of the Immune Response to α-Gal and Vector-borne Diseases.

    Science.gov (United States)

    Cabezas-Cruz, Alejandro; Mateos-Hernández, Lourdes; Pérez-Cruz, Magdiel; Valdés, James J; Mera, Isabel G Fernández de; Villar, Margarita; de la Fuente, José

    2015-10-01

    Vector-borne diseases (VBD) challenge our understanding of emerging diseases. Recently, arthropod vectors have been involved in emerging anaphylactic diseases. In particular, the immunoglobulin E (IgE) antibody response to the carbohydrate Galα1-3Galβ1-(3)4GlcNAc-R (α-gal) following a tick bite was associated with allergies to red meat, cetuximab, and gelatin. By contrast, an anti-α-gal IgM antibody response was shown to protect against mosquito-borne malaria. Herein, we highlight the interplay between the gut microbiota, vectors, transmitted pathogens, and the regulation of the immune response as a model to understand the protective or allergic effect of α-gal. Establishing the source of α-gal in arthropod vectors and the immune response to vector bites and transmitted pathogens will be essential for diagnosing, treating, and ultimately preventing these emerging anaphylactic and other vector-borne diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Integrated pest management and allocation of control efforts for vector-borne diseases

    Science.gov (United States)

    Ginsberg, H.S.

    2001-01-01

    Applications of various control methods were evaluated to determine how to integrate methods so as to minimize the number of human cases of vector-borne diseases. These diseases can be controlled by lowering the number of vector-human contacts (e.g., by pesticide applications or use of repellents), or by lowering the proportion of vectors infected with pathogens (e.g., by lowering or vaccinating reservoir host populations). Control methods should be combined in such a way as to most efficiently lower the probability of human encounter with an infected vector. Simulations using a simple probabilistic model of pathogen transmission suggest that the most efficient way to integrate different control methods is to combine methods that have the same effect (e.g., combine treatments that lower the vector population; or combine treatments that lower pathogen prevalence in vectors). Combining techniques that have different effects (e.g., a technique that lowers vector populations with a technique that lowers pathogen prevalence in vectors) will be less efficient than combining two techniques that both lower vector populations or combining two techniques that both lower pathogen prevalence, costs being the same. Costs of alternative control methods generally differ, so the efficiency of various combinations at lowering human contact with infected vectors should be estimated at available funding levels. Data should be collected from initial trials to improve the effects of subsequent interventions on the number of human cases.

  18. Legal aspects of public health: difficulties in controlling vector-borne and zoonotic diseases in Brazil.

    Science.gov (United States)

    Mendes, Marcílio S; de Moraes, Josué

    2014-11-01

    In recent years, vector-borne and zoonotic diseases have become a major challenge for public health. Dengue fever and leptospirosis are the most important communicable diseases in Brazil based on their prevalence and the healthy life years lost from disability. The primary strategy for preventing human exposure to these diseases is effective insect and rodent control in and around the home. However, health authorities have difficulties in controlling vector-borne and zoonotic diseases because residents often refuse access to their homes. This study discusses aspects related to the activities performed by Brazilian health authorities to combat vector-borne and zoonotic diseases, particularly difficulties in relation to the legal aspect, which often impede the quick and effective actions of these professionals. How might it be possible to reconcile the need to preserve public health and the rule on the inviolability of the home, especially in the case of abandoned properties or illegal residents and the refusal of residents to allow the health authority access? Do residents have the right to hinder the performance of health workers even in the face of a significant and visible focus of disease transmission? This paper argues that a comprehensive legal plan aimed at the control of invasive vector-borne and zoonotic diseases including synanthropic animals of public health importance should be considered. In addition, this paper aims to bridge the gap between lawyers and public health professionals and to facilitate communication between them. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Towards a resource-based habitat approach for spatial modelling of vector-borne disease risks

    NARCIS (Netherlands)

    Hartemink, N.; Vanwambeke, S.O.; Purse, B.V.; Gilbert, M.; Van Dyck, H.

    2015-01-01

    Given the veterinary and public health impact of vector-borne diseases, there is a clear need to assess the suitability of landscapes for the emergence and spread of these diseases. Current approaches for predicting disease risks neglect key features of the landscape as components of the functional

  20. Vector-Borne Infections in Tornado-Displaced and Owner-Relinquished Dogs in Oklahoma, USA.

    Science.gov (United States)

    Barrett, Anne W; Little, Susan E

    2016-06-01

    To determine the prevalence of infection with vector-borne agents in a cross-section of dogs from Oklahoma, where canine vector-borne diseases are common, blood samples were evaluated through serology and molecular analysis. Antibodies reactive to Ehrlichia spp., Rickettsia rickettsii, R. montanensis, and "R. amblyommii" were detected in 10.5% (11/105), 74.3% (78/105), 58.1% (61/105), and 55.2% (58/105) of dogs, respectively. Presence of spotted fever group Rickettsia spp. DNA was identified in 13.1% (8/61) of shelter dogs but not in any pet dogs (0/44). DNA of "R. amblyommii" was confirmed by sequencing, constituting the first report of this agent in a naturally infected dog. Antigen of Dirofilaria immitis was detected in 10.5% (11/105) and 16.2% (17/105) of samples before and after heat treatment, respectively. In total, 87.6% (92/105) of the dogs had evidence of infection with at least one vector-borne disease agent, confirming high risk of exposure to multiple vector-borne disease agents, several of which are zoonotic.

  1. Using the gravity model to estimate the spatial spread of vector-borne diseases

    NARCIS (Netherlands)

    Barrios, J.M.; Verstraeten, W.W.; Maes, P.; Aerts, J.; Farifteh, J.; Coppin, P.

    2012-01-01

    The gravity models are commonly used spatial interaction models. They have been widely applied in a large set of domains dealing with interactions amongst spatial entities. The spread of vector-borne diseases is also related to the intensity of interaction between spatial entities, namely, the

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

    Directory of Open Access Journals (Sweden)

    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.

  3. Using the Gravity Model to Estimate the Spatial Spread of Vector-Borne Diseases

    Directory of Open Access Journals (Sweden)

    Jean-Marie Aerts

    2012-11-01

    Full Text Available The gravity models are commonly used spatial interaction models. They have been widely applied in a large set of domains dealing with interactions amongst spatial entities. The spread of vector-borne diseases is also related to the intensity of interaction between spatial entities, namely, the physical habitat of pathogens’ vectors and/or hosts, and urban areas, thus humans. This study implements the concept behind gravity models in the spatial spread of two vector-borne diseases, nephropathia epidemica and Lyme borreliosis, based on current knowledge on the transmission mechanism of these diseases. Two sources of information on vegetated systems were tested: the CORINE land cover map and MODIS NDVI. The size of vegetated areas near urban centers and a local indicator of occupation-related exposure were found significant predictors of disease risk. Both the land cover map and the space-borne dataset were suited yet not equivalent input sources to locate and measure vegetated areas of importance for disease spread. The overall results point at the compatibility of the gravity model concept and the spatial spread of vector-borne diseases.

  4. Control of vector-borne infectious diseases by human immunity against α-Gal

    Czech Academy of Sciences Publication Activity Database

    Cabezas-Cruz, A.; Valdés, James J.; de la Fuente, J.

    2016-01-01

    Roč. 15, č. 8 (2016), s. 953-955 ISSN 1476-0584 EU Projects: European Commission(XE) 278976 - ANTIGONE Institutional support: RVO:60077344 Keywords : microbiota * probiotics * vaccine * α-Gal * vector-borne diseases Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 3.555, year: 2016

  5. [Important vector-borne infectious diseases among humans in Germany. Epidemiological aspects].

    Science.gov (United States)

    Frank, C; Faber, M; Hellenbrand, W; Wilking, H; Stark, K

    2014-05-01

    Vector-borne infections pathogenic to humans play an important role in Germany. The relevant zoonotic pathogens are either endemic throughout Germany (e.g. Borrelia burgdorferi sensu latu) or only in specific regions, e.g. tick-borne encephalitis (TBE) virus and hantavirus. They cause a substantial burden of disease. Prevention and control largely rely on public advice and the application of personal protective measures (e.g. TBE virus vaccination and protection against vectors). High quality surveillance and targeted epidemiological studies are fundamental for the evaluation of temporal and spatial risks of infection and the effectiveness of preventive measures. Aside from endemic pathogens, vector-borne infections acquired abroad, mostly transmitted by mosquitoes, have to be systematically and intensively monitored as well, to assess the risk of infection for German residents traveling abroad and to adequately evaluate the risk of autochthonous transmission. Related issues, such as invasive species of mosquitoes in Germany and climate change, have to be taken into consideration. Such pathogens include West Nile, dengue and chikungunya viruses, as well as malaria parasites (Plasmodium species). The article presents an overview of the epidemiological situation of selected relevant vector-borne infections in Germany.

  6. Vector-borne diseases and the basic reproduction number: a case study of African horse sickness

    NARCIS (Netherlands)

    Lord, C.C.; Woolhouse, M.E.J.; Heesterbeek, J.A.P.; Mellor, P.S.

    1996-01-01

    The basic reproduction number, R0, can be used to determine factors important in the ability of a disease to invade or persist. We show how this number can be derived or estimated for vector-borne diseases with different complicating factors. African horse sickness is a viral disease transmitted

  7. A surface hydrology model for regional vector borne disease models

    Science.gov (United States)

    Tompkins, Adrian; Asare, Ernest; Bomblies, Arne; Amekudzi, Leonard

    2016-04-01

    Small, sun-lit temporary pools that form during the rainy season are important breeding sites for many key mosquito vectors responsible for the transmission of malaria and other diseases. The representation of this surface hydrology in mathematical disease models is challenging, due to their small-scale, dependence on the terrain and the difficulty of setting soil parameters. Here we introduce a model that represents the temporal evolution of the aggregate statistics of breeding sites in a single pond fractional coverage parameter. The model is based on a simple, geometrical assumption concerning the terrain, and accounts for the processes of surface runoff, pond overflow, infiltration and evaporation. Soil moisture, soil properties and large-scale terrain slope are accounted for using a calibration parameter that sets the equivalent catchment fraction. The model is calibrated and then evaluated using in situ pond measurements in Ghana and ultra-high (10m) resolution explicit simulations for a village in Niger. Despite the model's simplicity, it is shown to reproduce the variability and mean of the pond aggregate water coverage well for both locations and validation techniques. Example malaria simulations for Uganda will be shown using this new scheme with a generic calibration setting, evaluated using district malaria case data. Possible methods for implementing regional calibration will be briefly discussed.

  8. 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.

  9. 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.

  10. 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

  11. Seasonal forcing in a host-macroparasite system.

    Science.gov (United States)

    Taylor, Rachel A; White, Andrew; Sherratt, Jonathan A

    2015-01-21

    Seasonal forcing represents a pervasive source of environmental variability in natural systems. Whilst it is reasonably well understood in interacting populations and host-microparasite systems, it has not been studied in detail for host-macroparasite systems. In this paper we analyse the effect of seasonal forcing in a general host-macroparasite system with explicit inclusion of the parasite larval stage and seasonal forcing applied to the birth rate of the host. We emphasise the importance of the period of the limit cycles in the unforced system on the resulting dynamics in the forced system. In particular, when subject to seasonal forcing host-macroparasite systems are capable of multi-year cycles, multiple solution behaviour, quasi-periodicity and chaos. The host-macroparasite systems show a larger potential for multiple solution behaviour and a wider range of periodic solutions compared to similar interacting population and microparasite systems. By examining the system for parameters that represent red grouse and the macroparasite nematode Trichostrongylus tenuis we highlight how seasonality could be an important factor in explaining the wide range of seemingly uncorrelated cycle periods observed in grouse abundance in England and Scotland. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Potential impact of climate change on emerging vector-borne and other infections in the UK.

    Science.gov (United States)

    Baylis, Matthew

    2017-12-05

    Climate is one of several causes of disease emergence. Although half or more of infectious diseases are affected by climate it appears to be a relatively infrequent cause of human disease emergence. Climate mostly affects diseases caused by pathogens that spend part of their lifecycle outside of the host, exposed to the environment. The most important routes of transmission of climate sensitive diseases are by arthropod (insect and tick) vectors, in water and in food. Given the sensitivity of many diseases to climate, it is very likely that at least some will respond to future climate change. In the case of vector-borne diseases this response will include spread to new areas. Several vector-borne diseases have emerged in Europe in recent years; these include vivax malaria, West Nile fever, dengue fever, Chikungunya fever, leishmaniasis, Lyme disease and tick-borne encephalitis. The vectors of these diseases are mosquitoes, sand flies and ticks. The UK has endemic mosquito species capable of transmitting malaria and probably other pathogens, and ticks that transmit Lyme disease. The UK is also threatened by invasive mosquito species known to be able to transmit West Nile, dengue, chikungunya and Zika, and sand flies that spread leishmaniasis. Warmer temperatures in the future will increase the suitability of the UK's climate for these invasive species, and increase the risk that they may spread disease. While much attention is on invasive species, it is important to recognize the threat presented by native species too. Proposed actions to reduce the future impact of emerging vector-borne diseases in the UK include insect control activity at points of entry of vehicles and certain goods, wider surveillance for mosquitoes and sand flies, research into the threat posed by native species, increased awareness of the medical profession of the threat posed by specific diseases, regular risk assessments, and increased preparedness for the occurrence of a disease emergency.

  13. Towards an integrated approach in surveillance of vector-borne diseases in Europe

    Science.gov (United States)

    2011-01-01

    Vector borne disease (VBD) emergence is a complex and dynamic process. Interactions between multiple disciplines and responsible health and environmental authorities are often needed for an effective early warning, surveillance and control of vectors and the diseases they transmit. To fully appreciate this complexity, integrated knowledge about the human and the vector population is desirable. In the current paper, important parameters and terms of both public health and medical entomology are defined in order to establish a common language that facilitates collaboration between the two disciplines. Special focus is put on the different VBD contexts with respect to the current presence or absence of the disease, the pathogen and the vector in a given location. Depending on the context, whether a VBD is endemic or not, surveillance activities are required to assess disease burden or threat, respectively. Following a decision for action, surveillance activities continue to assess trends. PMID:21967706

  14. Wildlife as reservoirs for vector borne diseases in a warmer Scandinavian climate

    DEFF Research Database (Denmark)

    Bødker, Rene; Kristensen, Birgit

    can be attributed global warming. Some of these new infections have important reservoirs in wild animals and this may affect prevention and control of outbreaks in humans and domestic animals. This may also put wild animals at risk of not just infections but also of control efforts targeted...... of the future risk of outbreaks in the Nordic countries. DTU Veterinary Institute is developing a system for continuous risk assessment of potential spread of exotic insect borne diseases of veterinary and human importance. Mathematical models for selected vector borne diseases are continuously updated...

  15. Spatially explicit multi-criteria decision analysis for managing vector-borne diseases

    Science.gov (United States)

    2011-01-01

    The complex epidemiology of vector-borne diseases creates significant challenges in the design and delivery of prevention and control strategies, especially in light of rapid social and environmental changes. Spatial models for predicting disease risk based on environmental factors such as climate and landscape have been developed for a number of important vector-borne diseases. The resulting risk maps have proven value for highlighting areas for targeting public health programs. However, these methods generally only offer technical information on the spatial distribution of disease risk itself, which may be incomplete for making decisions in a complex situation. In prioritizing surveillance and intervention strategies, decision-makers often also need to consider spatially explicit information on other important dimensions, such as the regional specificity of public acceptance, population vulnerability, resource availability, intervention effectiveness, and land use. There is a need for a unified strategy for supporting public health decision making that integrates available data for assessing spatially explicit disease risk, with other criteria, to implement effective prevention and control strategies. Multi-criteria decision analysis (MCDA) is a decision support tool that allows for the consideration of diverse quantitative and qualitative criteria using both data-driven and qualitative indicators for evaluating alternative strategies with transparency and stakeholder participation. Here we propose a MCDA-based approach to the development of geospatial models and spatially explicit decision support tools for the management of vector-borne diseases. We describe the conceptual framework that MCDA offers as well as technical considerations, approaches to implementation and expected outcomes. We conclude that MCDA is a powerful tool that offers tremendous potential for use in public health decision-making in general and vector-borne disease management in particular

  16. Spatially explicit multi-criteria decision analysis for managing vector-borne diseases

    Directory of Open Access Journals (Sweden)

    Hongoh Valerie

    2011-12-01

    Full Text Available Abstract The complex epidemiology of vector-borne diseases creates significant challenges in the design and delivery of prevention and control strategies, especially in light of rapid social and environmental changes. Spatial models for predicting disease risk based on environmental factors such as climate and landscape have been developed for a number of important vector-borne diseases. The resulting risk maps have proven value for highlighting areas for targeting public health programs. However, these methods generally only offer technical information on the spatial distribution of disease risk itself, which may be incomplete for making decisions in a complex situation. In prioritizing surveillance and intervention strategies, decision-makers often also need to consider spatially explicit information on other important dimensions, such as the regional specificity of public acceptance, population vulnerability, resource availability, intervention effectiveness, and land use. There is a need for a unified strategy for supporting public health decision making that integrates available data for assessing spatially explicit disease risk, with other criteria, to implement effective prevention and control strategies. Multi-criteria decision analysis (MCDA is a decision support tool that allows for the consideration of diverse quantitative and qualitative criteria using both data-driven and qualitative indicators for evaluating alternative strategies with transparency and stakeholder participation. Here we propose a MCDA-based approach to the development of geospatial models and spatially explicit decision support tools for the management of vector-borne diseases. We describe the conceptual framework that MCDA offers as well as technical considerations, approaches to implementation and expected outcomes. We conclude that MCDA is a powerful tool that offers tremendous potential for use in public health decision-making in general and vector-borne

  17. Molecular detection of vector-borne bacteria and protozoa in healthy hunting dogs from Central Italy

    Directory of Open Access Journals (Sweden)

    Valentina Virginia Ebani

    2015-02-01

    Conclusions:: The results demonstrated that several vector-borne pathogens were circulating in this region and dogs infected by these agents were usually asymptomatic. A relevant finding was the presence of DNA of C. burnetii, a severe zoonotic agent, in the 5.1% of tested dogs, which can be source of infection for their owners not only through tick bites, but also directly with urine, feces and birth products.

  18. Vector-borne transmission of Trypanosoma cruzi among captive Neotropical primates in a Brazilian zoo.

    Science.gov (United States)

    Minuzzi-Souza, Thaís Tâmara Castro; Nitz, Nadjar; Knox, Monique Britto; Reis, Filipe; Hagström, Luciana; Cuba, César A Cuba; Hecht, Mariana Machado; Gurgel-Gonçalves, Rodrigo

    2016-01-26

    Neotropical primates are important sylvatic hosts of Trypanosoma cruzi, the etiological agent of Chagas disease. Infection is often subclinical, but severe disease has been described in both free-ranging and captive primates. Panstrongylus megistus, a major T. cruzi vector, was found infesting a small-primate unit at Brasília zoo (ZooB), Brazil. ZooB lies close to a gallery-forest patch where T. cruzi circulates naturally. Here, we combine parasitological and molecular methods to investigate a focus of T. cruzi infection involving triatomine bugs and Neotropical primates at a zoo located in the Brazilian Savannah. We assessed T. cruzi infection in vectors using optical microscopy (n = 34) and nested PCR (n = 50). We used quantitative PCR (qPCR) to examine blood samples from 26 primates and necropsy samples from two primates that died during the study. We determined parasite lineages in five vectors and two primates by comparing glucose-6-phosphate isomerase (G6pi) gene sequences. Trypanosoma cruzi was found in 44 vectors and 17 primates (six genera and eight species); one Mico chrysoleucus and one Saguinus niger had high parasitaemias. Trypanosoma cruzi DNA was detected in three primates born to qPCR-negative mothers at ZooB and in the two dead specimens. One Callithrix geoffroyi became qPCR-positive over a two-year follow-up. All G6pi sequences matched T. cruzi lineage TcI. Our findings strongly suggest vector-borne T. cruzi transmission within a small-primate unit at ZooB - with vectors, and perhaps also parasites, presumably coming from nearby gallery forest. Periodic checks for vectors and parasites would help eliminate T. cruzi transmission foci in captive-animal facilities. This should be of special importance for captive-breeding programs involving endangered mammals, and would reduce the risk of accidental T. cruzi transmission to keepers and veterinarians.

  19. Natural Mosquito-Pathogen Hybrid IgG4 Antibodies in Vector Borne Diseases: A Hypothesis

    Directory of Open Access Journals (Sweden)

    Berlin L. Londono-Renteria

    2016-09-01

    Full Text Available Chronic exposure to antigens may favor the production of IgG4 antibodies over other antibody types. Recent studies have shown that up to a 30% of normal human IgG4 is bi-specific and is able to recognize two antigens of different nature. A requirement for this specificity is the presence of both eliciting antigens in the same time and at the same place where the immune response is induced. During transmission of most vector-borne diseases, the pathogen is delivered to the vertebrate host along with the arthropod saliva during blood feeding and previous studies have shown the existence of IgG4 antibodies against mosquito salivary allergens. However, there is very little ongoing research or information available regarding IgG4 bi-specificity with regards to infectious disease, particularly during immune responses to vector-borne diseases such as malaria, filariasis or dengue virus infection. Here, we provide background information and present our hypothesis that IgG4 may not only be a useful tool to measure exposure to infected mosquito bites, but that these bi-specific antibodies may also play an important role in modulation of the immune response against malaria and other vector-borne diseases in endemic settings.

  20. 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.

  1. Climate Change and Vector Borne Diseases on NASA Langley Research Center

    Science.gov (United States)

    Cole, Stuart K.; DeYoung, Russell J.; Shepanek, Marc A.; Kamel, Ahmed

    2014-01-01

    Increasing global temperature, weather patterns with above average storm intensities, and higher sea levels have been identified as phenomena associated with global climate change. As a causal system, climate change could contribute to vector borne diseases in humans. Vectors of concern originate from the vicinity of Langley Research Center include mosquitos and ticks that transmit disease that originate regionally, nationwide, or from outside the US. Recognizing changing conditions, vector borne diseases propagate under climate change conditions, and understanding the conditions in which they may exist or propagate, presents opportunities for monitoring their progress and mitigating their potential impacts through communication, continued monitoring, and adaptation. Personnel comprise a direct and fundamental support to NASA mission success, continuous and improved understanding of climatic conditions, and the resulting consequence of disease from these conditions, helps to reduce risk in terrestrial space technologies, ground operations, and space research. This research addresses conditions which are attributed to climatic conditions which promote environmental conditions conducive to the increase of disease vectors. This investigation includes evaluation of local mosquito population count and rainfall data for statistical correlation and identification of planning recommendations unique to LaRC, other NASA Centers to assess adaptation approaches, Center-level planning strategies.

  2. 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.

  3. Genetic shifting: a novel approach for controlling vector-borne diseases.

    Science.gov (United States)

    Powell, Jeffrey R; Tabachnick, Walter J

    2014-06-01

    Rendering populations of vectors of diseases incapable of transmitting pathogens through genetic methods has long been a goal of vector geneticists. We outline a method to achieve this goal that does not involve the introduction of any new genetic variants to the target population. Rather we propose that shifting the frequencies of naturally occurring alleles that confer refractoriness to transmission can reduce transmission below a sustainable level. The program employs methods successfully used in plant and animal breeding. Because no artificially constructed genetically modified organisms (GMOs) are introduced into the environment, the method is minimally controversial. We use Aedes aegypti and dengue virus (DENV) for illustrative purposes but point out that the proposed program is generally applicable to vector-borne disease control. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Modeling the spread of vector-borne diseases on bipartite networks.

    Directory of Open Access Journals (Sweden)

    Donal Bisanzio

    Full Text Available BACKGROUND: Vector-borne diseases for which transmission occurs exclusively between vectors and hosts can be modeled as spreading on a bipartite network. METHODOLOGY/PRINCIPAL FINDINGS: In such models the spreading of the disease strongly depends on the degree distribution of the two classes of nodes. It is sufficient for one of the classes to have a scale-free degree distribution with a slow enough decay for the network to have asymptotically vanishing epidemic threshold. Data on the distribution of Ixodes ricinus ticks on mice and lizards from two independent studies are well described by a scale-free distribution compatible with an asymptotically vanishing epidemic threshold. The commonly used negative binomial, instead, cannot describe the right tail of the empirical distribution. CONCLUSIONS/SIGNIFICANCE: The extreme aggregation of vectors on hosts, described by the power-law decay of the degree distribution, makes the epidemic threshold decrease with the size of the network and vanish asymptotically.

  5. [Climate change - a pioneer for the expansion of canine vector-borne diseases?].

    Science.gov (United States)

    Krämer, F; Mencke, N

    2011-01-01

    Vector-transmitted diseases are one of the major contributors to the global burden of disease in humans and animals. Climate change is consistently held responsible for the spread of parasitic acarid and insect vectors such as ticks, fleas, sand flies and mosquitoes, and their transmitted pathogens (in the case of the dog the so-called canine vector-borne diseases [CVBD]). Currently, there is only insufficient data available to prove whether climate change is a major driving force for vector and disease expansion, but the evidence is growing. Other reasons, such as ecological, demographic and socio-economic factors, e.g. pet travel into and pet import from endemic areas, also play a role in this development. Apart from all the controversial discussion of the factors leading to vector and disease expansion, preventative measures should include dog owners' education as they are responsible for individual parasite protection as well as for the minimisation of adverse risk behaviour, e.g. regarding pet travel. Broad-spectrum vector control should be practised by using parasiticides that repel and kill blood feeders in order to minimize the risk of CVBD-pathogen transmission.

  6. Mapping of courses on vector biology and vector-borne diseases systems: time for a worldwide effort

    Science.gov (United States)

    Casas, Jérôme; Lazzari, Claudio; Insausti, Teresita; Launois, Pascal; Fouque, Florence

    2016-01-01

    Major emergency efforts are being mounted for each vector-borne disease epidemiological crisis anew, while knowledge about the biology of arthropods vectors is dwindling slowly but continuously, as is the number of field entomologists. The discrepancy between the rates of production of knowledge and its use and need for solving crises is widening, in particular due to the highly differing time spans of the two concurrent processes. A worldwide web based search using multiple key words and search engines of onsite and online courses in English, Spanish, Portuguese, French, Italian and German concerned with the biology of vectors identified over 140 courses. They are geographically and thematically scattered, the vast majority of them are on-site, with very few courses using the latest massive open online course (MOOC) powerfulness. Over two third of them is given in English and Western Africa is particularity poorly represented. The taxonomic groups covered are highly unbalanced towards mosquitoes. A worldwide unique portal to guide students of all grades and levels of expertise, in particular those in remote locations, is badly needed. This is the objective a new activity supported by the Special Programme for Research and Training in Tropical Diseases (TDR). PMID:27759770

  7. Zoonotic intestinal parasites and vector-borne pathogens in Italian shelter and kennel dogs.

    Science.gov (United States)

    Traversa, Donato; Di Cesare, Angela; Simonato, Giulia; Cassini, Rudi; Merola, Carmine; Diakou, Anastasia; Halos, Lénaïg; Beugnet, Frederic; Frangipane di Regalbono, Antonio

    2017-04-01

    This study investigated the presence of zoonotic parasites and vector-borne pathogens in dogs housed in kennels and shelters from four sites of Italy. A total of 150 adoptable dogs was examined with different microscopic, serological and molecular methods. Overall 129 dogs (86%) were positive for one or more parasites and/or pathogens transmitted by ectoparasites. Forty-eight (32%) were positive for one infection, while 81 (54%) for more than one pathogen. The most common zoonotic helminths recorded were hookworms, roundworms and Capillaria aerophila, followed by mosquito-borne Dirofilaria spp. and Dipylidium caninum. One hundred and thirteen (77.9%), 6 (4.1%) and 2 (1.4%) dogs were positive for Rickettsia spp., Leishmania infantum and Anaplasma spp., respectively. The results show that dogs living in rescue facilities from the studied areas may be infected by many zoonotic internal parasites and vector-borne pathogens, and that control measures should be implemented. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. The impact of global environmental change on vector-borne disease risk: a modelling study

    Directory of Open Access Journals (Sweden)

    Rachel Lowe, PhD

    2018-05-01

    Full Text Available Background: Vector-borne diseases, such as dengue virus, Zika virus, and malaria, are highly sensitive to environmental changes, including variations in climate and land-surface characteristics. The emergence and spread of vector-borne diseases is also exacerbated by anthropogenic activities, such as deforestation, mining, urbanisation, and human mobility, which alter the natural habitats of vectors and increase vector–host interactions. Innovative epidemiological modelling tools can help to understand how environmental conditions interact with socioeconomic risk factors to predict the risk of disease transmission. In recent years, climate-health modelling has benefited from computational advances in fitting complex mathematical models; increasing availability of environmental, socioeconomic, and disease surveillance datasets; and improved ability to understand and model the climate system. Climate forecasts at seasonal time scales tend to improve in quality during El Niño-Southern Oscillation events in certain regions of the tropics. Thus, climate forecasts provide an opportunity to anticipate potential outbreaks of vector-borne diseases from several months to a year in advance. The aim of this study was to develop a framework to incorporate seasonal climate forecasts in predictive disease models to understand the future risk of vector-borne diseases, with a focus on dengue fever in Latin America. Methods: A Bayesian spatiotemporal model framework that quantifies the extent to which environmental and socioeconomic indicators can explain variations in disease risk was designed to disentangle the effects of climate from other risk factors using multi-source data and random effects, which account for unknown and unmeasured sources of spatial, seasonal, and inter-annual variation. The model was used to provide probabilistic predictions of monthly dengue incidence and the probability of exceeding outbreak thresholds, which were established in

  9. Fleas, hosts and habitat: What can we predict about the spread of vector-borne zoonotic diseases?

    Science.gov (United States)

    Megan M. Friggens

    2010-01-01

    Vector-borne diseases of humans and wildlife are experiencing resurgence across the globe. I examine the dynamics of flea borne diseases through a comparative analysis of flea literature and analyses of field data collected from three sites in New Mexico: The Sevilleta National Wildlife Refuge, the Sandia Mountains and the Valles Caldera National Preserve (VCNP). My...

  10. A PCR survey of vector-borne pathogens in different dog populations from Turkey.

    Science.gov (United States)

    Guo, Huanping; Sevinc, Ferda; Ceylan, Onur; Sevinc, Mutlu; Ince, Ege; Gao, Yang; Moumouni, Paul Franck Adjou; Liu, Mingming; Efstratiou, Artemis; Wang, Guanbo; Cao, Shinuo; Zhou, Mo; Jirapattharasate, Charoonluk; Ringo, Aaron Edmond; Zheng, Weiqing; Xuan, Xuenan

    2017-09-26

    In the present study, a total of 192 blood samples were collected from pet dogs, kennel dogs and shepherd dogs in Konya district, Turkey, and tested by specific PCR for the presence of vector-borne pathogens. Several pathogens were identified, most of which can cause substantial morbidity in dogs. PCR results revealed that 54 (28.1%) dogs were infected with one or more pathogens. Positive results were obtained for Babesia spp. in 4 dogs (2.1%), Hepatozoon spp. in 8 dogs (4.2%) and Mycoplasma spp. in 46 dogs (24%). Three dogs (1.6%) were infected with two or three pathogens. The sequence analysis of the positive DNA samples revealed the presence of Babesia canis vogeli, Hepatozoon canis, Hepatozoon sp. MF, Mycoplasma haemocanis and Candidatus Mycoplasma haematoparvum. Ehrlichia canis and Anaplasma platys were not detected. Regardless of ownership status, vector-borne diseases were common in these dog populations. There was significant difference of pathogen prevalence among the different dog populations. Mycoplasma spp. was more frequent in the kennel dogs (31.9%) than in the pet (21.4%) and shepherd dogs (13.8%). Additionally, the frequency of Babesia spp. and Hepatozoon spp. was higher in the shepherd dogs which account for three quarters and half of the total number of Babesia spp. and Hepatozoon spp., respectively. To our knowledge, this is the first report of Mycoplasma infection in dogs in Turkey. The results of the present study provide a foundation for understanding the epidemiology of canine vector-borne diseases (CVBDs), and for strategies to control these diseases in Turkey.

  11. An antivector vaccine protects against a lethal vector-borne pathogen.

    Directory of Open Access Journals (Sweden)

    Milan Labuda

    2006-04-01

    Full Text Available Vaccines that target blood-feeding disease vectors, such as mosquitoes and ticks, have the potential to protect against the many diseases caused by vector-borne pathogens. We tested the ability of an anti-tick vaccine derived from a tick cement protein (64TRP of Rhipicephalus appendiculatus to protect mice against tick-borne encephalitis virus (TBEV transmitted by infected Ixodes ricinus ticks. The vaccine has a "dual action" in immunized animals: when infested with ticks, the inflammatory and immune responses first disrupt the skin feeding site, resulting in impaired blood feeding, and then specific anti-64TRP antibodies cross-react with midgut antigenic epitopes, causing rupture of the tick midgut and death of engorged ticks. Three parameters were measured: "transmission," number of uninfected nymphal ticks that became infected when cofeeding with an infected adult female tick; "support," number of mice supporting virus transmission from the infected tick to cofeeding uninfected nymphs; and "survival," number of mice that survived infection by tick bite and subsequent challenge by intraperitoneal inoculation of a lethal dose of TBEV. We show that one dose of the 64TRP vaccine protects mice against lethal challenge by infected ticks; control animals developed a fatal viral encephalitis. The protective effect of the 64TRP vaccine was comparable to that of a single dose of a commercial TBEV vaccine, while the transmission-blocking effect of 64TRP was better than that of the antiviral vaccine in reducing the number of animals supporting virus transmission. By contrast, the commercial antitick vaccine (TickGARD that targets only the tick's midgut showed transmission-blocking activity but was not protective. The 64TRP vaccine demonstrates the potential to control vector-borne disease by interfering with pathogen transmission, apparently by mediating a local cutaneous inflammatory immune response at the tick-feeding site.

  12. R0 for vector-borne diseases: impact of the assumption for the duration of the extrinsic incubation period

    NARCIS (Netherlands)

    Hartemink, Nienke; Cianci, Daniela; Reiter, Paul

    2015-01-01

    Mathematical modeling and notably the basic reproduction number R0 have become popular tools for the description of vector-borne disease dynamics. We compare two widely used methods to calculate the probability of a vector to survive the extrinsic incubation period. The two methods are based on

  13. Wildlife reservoirs for vector-borne canine, feline and zoonotic infections in Austria

    Directory of Open Access Journals (Sweden)

    Georg G. Duscher

    2015-04-01

    The role of wild ungulates, especially ruminants, as reservoirs for zoonotic disease on the other hand seems to be negligible, although the deer filaroid Onchocerca jakutensis has been described to infect humans. Deer may also harbour certain Anaplasma phagocytophilum strains with so far unclear potential to infect humans. The major role of deer as reservoirs is for ticks, mainly adults, thus maintaining the life cycle of these vectors and their distribution. Wild boar seem to be an exception among the ungulates as, in their interaction with the fox, they can introduce food-borne zoonotic agents such as Trichinella britovi and Alaria alata into the human food chain.

  14. Schools as Potential Risk Sites for Vector-Borne Disease Transmission: Mosquito Vectors in Rural Schools in Two Municipalities in Colombia.

    Science.gov (United States)

    Olano, Víctor Alberto; Matiz, María Inés; Lenhart, Audrey; Cabezas, Laura; Vargas, Sandra Lucía; Jaramillo, Juan Felipe; Sarmiento, Diana; Alexander, Neal; Stenström, Thor Axel; Overgaard, Hans J

    2015-09-01

    Dengue and other vector-borne diseases are of great public health importance in Colombia. Vector surveillance and control activities are often focused at the household level. Little is known about the importance of nonhousehold sites, including schools, in maintaining vector-borne disease transmission. The objectives of this paper were to determine the mosquito species composition in rural schools in 2 municipalities in Colombia and to assess the potential risk of vector-borne disease transmission in school settings. Entomological surveys were carried out in rural schools during the dry and rainy seasons of 2011. A total of 12 mosquito species were found: Aedes aegypti, Anopheles pseudopunctipennis, Culex coronator, Cx. quinquefasciatus, and Limatus durhamii in both immature and adult forms; Ae. fluviatilis, Cx. nigripalpus, Cx. corniger, and Psorophora ferox in immature forms only; and Ae. angustivittatus, Haemagogus equinus, and Trichoprosopon lampropus in adult forms only. The most common mosquito species was Cx. quinquefasciatus. Classrooms contained the greatest abundance of adult female Ae. aegypti and Cx. quinquefasciatus. The most common Ae. aegypti breeding sites were containers classified as "others" (e.g., cans), followed by containers used for water storage. A high level of Ae. aegypti infestation was found during the wet season. Our results suggest that rural schools are potentially important foci for the transmission of dengue and other mosquito-borne diseases. We propose that public health programs should be implemented in rural schools to prevent vector-borne diseases.

  15. Towards a resource-based habitat approach for spatial modelling of vector-borne disease risks.

    Science.gov (United States)

    Hartemink, Nienke; Vanwambeke, Sophie O; Purse, Bethan V; Gilbert, Marius; Van Dyck, Hans

    2015-11-01

    Given the veterinary and public health impact of vector-borne diseases, there is a clear need to assess the suitability of landscapes for the emergence and spread of these diseases. Current approaches for predicting disease risks neglect key features of the landscape as components of the functional habitat of vectors or hosts, and hence of the pathogen. Empirical-statistical methods do not explicitly incorporate biological mechanisms, whereas current mechanistic models are rarely spatially explicit; both methods ignore the way animals use the landscape (i.e. movement ecology). We argue that applying a functional concept for habitat, i.e. the resource-based habitat concept (RBHC), can solve these issues. The RBHC offers a framework to identify systematically the different ecological resources that are necessary for the completion of the transmission cycle and to relate these resources to (combinations of) landscape features and other environmental factors. The potential of the RBHC as a framework for identifying suitable habitats for vector-borne pathogens is explored and illustrated with the case of bluetongue virus, a midge-transmitted virus affecting ruminants. The concept facilitates the study of functional habitats of the interacting species (vectors as well as hosts) and provides new insight into spatial and temporal variation in transmission opportunities and exposure that ultimately determine disease risks. It may help to identify knowledge gaps and control options arising from changes in the spatial configuration of key resources across the landscape. The RBHC framework may act as a bridge between existing mechanistic and statistical modelling approaches. © 2014 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.

  16. Challenges in predicting climate and environmental effects on vector-borne disease episystems in a changing world.

    Science.gov (United States)

    Tabachnick, W J

    2010-03-15

    Vector-borne pathogens cause enormous suffering to humans and animals. Many are expanding their range into new areas. Dengue, West Nile and Chikungunya have recently caused substantial human epidemics. Arthropod-borne animal diseases like Bluetongue, Rift Valley fever and African horse sickness pose substantial threats to livestock economies around the world. Climate change can impact the vector-borne disease epidemiology. Changes in climate will influence arthropod vectors, their life cycles and life histories, resulting in changes in both vector and pathogen distribution and changes in the ability of arthropods to transmit pathogens. Climate can affect the way pathogens interact with both the arthropod vector and the human or animal host. Predicting and mitigating the effects of future changes in the environment like climate change on the complex arthropod-pathogen-host epidemiological cycle requires understanding of a variety of complex mechanisms from the molecular to the population level. Although there has been substantial progress on many fronts the challenges to effectively understand and mitigate the impact of potential changes in the environment on vector-borne pathogens are formidable and at an early stage of development. The challenges will be explored using several arthropod-borne pathogen systems as illustration, and potential avenues to meet the challenges will be presented.

  17. Prevalence of selected zoonotic and vector-borne agents in dogs and cats in Costa Rica.

    Science.gov (United States)

    Scorza, Andrea V; Duncan, Colleen; Miles, Laura; Lappin, Michael R

    2011-12-29

    To estimate the prevalence of enteric parasites and selected vector-borne agents of dogs and cats in San Isidro de El General, Costa Rica, fecal and serum samples were collected from animals voluntarily undergoing sterilization. Each fecal sample was examined for parasites by microscopic examination after fecal flotation and for Giardia and Cryptosporidium using an immunofluorescence assay (IFA). Giardia and Cryptosporidium IFA positive samples were genotyped after PCR amplification of specific DNA if possible. The seroprevalence rates for the vector-borne agents (Dirofilaria immitis, Borrelia burgdorferi, Ehrlichia canis, and Anaplasma phagocytophilum) were estimated based on results from a commercially available ELISA. Enteric parasites were detected in samples from 75% of the dogs; Ancylostoma caninum, Trichuris vulpis, Giardia, and Toxocara canis were detected. Of the cats, 67.5% harbored Giardia spp., Cryptosporidium spp., Ancylostoma tubaeforme, or Toxocara cati. Both Cryptosporidium spp. isolates that could be sequenced were Cryptosporidium parvum (one dog isolate and one cat isolate). Of the Giardia spp. isolates that were successfully sequenced, the 2 cat isolates were assemblage A and the 2 dog isolates were assemblage D. D. immitis antigen and E. canis antibodies were identified in 2.3% and 3.5% of the serum samples, respectively. The prevalence of enteric zoonotic parasites in San Isidro de El General in Costa Rica is high in companion animals and this information should be used to mitigate public health risks. Copyright © 2011. Published by Elsevier B.V.

  18. Study of the climatic change impact on vector-borne diseases in West Africa: the case of tick-borne borreliosis and malaria

    International Nuclear Information System (INIS)

    Trape, J.F.

    2005-04-01

    Malaria and tick-borne borreliosis are the two first causes of morbidity due to vector-borne diseases in a large part of Sudan-sahelian West Africa. They are also the two tropical diseases which have been the most affected by climatic change in recent years. In the case of tick-borne borreliosis it has been shown in Senegal that the persistence of drought since the years 70 has been associated with a considerable extension of the geographic range of diseases and the vector tick A-sonrai, a species that was in the past limited to the Sahara and Sahel. In the case of malaria, drought has strongly reduced in these same regions of Africa the distribution, abundance and infection rate of Anopheline mosquitoes, but without any significant reduction of the burden of malaria for most populations concerned. The emergence and spread of Plasmodium falciparum resistance to antimalarial drugs only explain part of this phenomenon. (A.L.B.)

  19. Vector-borne disease surveillance in livestock populations: a critical review of literature recommendations and implemented surveillance (BTV-8) in five European countries

    DEFF Research Database (Denmark)

    Dórea, Fernanda C.; Elbers, Armin R.W.; Hendrikx, Pascal

    2016-01-01

    Preparedness against vector-borne threats depends on the existence of a long-term, sustainable surveillance of vector-borne disease and their relevant vectors. This work reviewed the availability of such surveillance systems in five European countries (Denmark, France, The Netherlands, Sweden and...

  20. Distribution and prevalence of vector-borne diseases in California chipmunks (Tamias spp..

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    Mary H Straub

    Full Text Available California, with 13 chipmunk (Tamias species, has more than any other state or country, occupying habitats ranging from chaparral to the high peaks of the Sierra Nevada. Chipmunks host zoonotic pathogens including Yersinia pestis, Anaplasma phagocytophilum, relapsing fever (RF Borrelia spp., Borrelia burgdorferi, and spotted fever group (SFG Rickettsia species. Chipmunk species are often not differentiated by public health workers, yet different species utilize different ecological niches and may have intrinsically different capacities for maintaining vector-borne pathogens and infecting vectors. We surveyed over 700 individuals from nine species of chipmunks throughout California for exposure to and infection by Y. pestis, A. phagocytophilum, RF Borrelia spp., Borrelia burgdorferi, and SFG Rickettsia species. DNA of all five pathogens was found and all chipmunks except Merriam's chipmunk (T. merriami were PCR-positive for at least one of the pathogens. Anaplasma phagocytophilum was most common (40.0%, 2/5 in Sonoma chipmunks (T. sonomae from Marin county and B. burgdorferi most common (37.5%, 27/72 in redwood chipmunks (T. ochrogenys from Mendocino county. RF Borrelia spp. was detected in 2% (6/297 of redwood chipmunks in Mendocino county and 10% (1/10 of both least (T. minimus and lodgepole (T. speciosus chipmunks in the western Sierra. Exposure to SFG Rickettsia spp. was found in the Northern Coastal region (Del Norte, Humboldt and Mendocino counties and in the northern and western Sierra in several species of chipmunks. Y. pestis infection was found only in the western Sierra-in a yellow-pine (T. amoenus and a long-eared (T. quadrimaculatus chipmunk. Though more data are needed to thoroughly understand the roles that different chipmunk species play in disease transmission, our findings suggest that some chipmunk species may be more important to the maintenance of vector-borne diseases than others within each geographic area.

  1. Continuous host-macroparasite models with application to aquaculture

    Directory of Open Access Journals (Sweden)

    Catherine Bouloux Marquet

    2004-11-01

    Full Text Available We study a continuous deterministic host-macroparasite system which involves populations of hosts, parasites, and larvae. This system leads to a countable number of partial differential equations that under certain hypotheses, is reduced to finitely many equations. Also we assume hypotheses to close the system and to define the global dynamics for the hosts. Then, we analyze the spatially homogeneous model without demography (aquaculture hypothesis, and show some preliminary results for the spatially structured model.

  2. Canine babesiosis in northern Portugal and molecular characterization of vector-borne co-infections

    Science.gov (United States)

    2010-01-01

    Background Protozoa and bacteria transmitted by arthropods, including ticks and phlebotomine sand flies, may cause a wide range of canine vector-borne diseases. Dogs can be simultaneously or sequentially infected with multiple pathogens. Canine babesiosis caused by Babesia canis canis and Babesia canis vogeli is known to occur in Portugal. This study assessed, by means of blood smear examination, PCR and DNA nucleotide sequencing, the presence of Babesia spp. and co-infecting agents Leishmania, Anaplasma/Ehrlichia and Hepatozoon in 45 dogs from northern Portugal clinically suspected of babesiosis. Results Forty-four dogs (98%) had infection with B. canis canis and one with B. canis vogeli. Co-infections were detected in nine animals (20%). Eight dogs were found infected with two vector-borne agents: six with B. canis canis and Leishmania infantum; one with B. canis canis and Ehrlichia canis; and one with B. canis canis and Hepatozoon canis. Another dog was infected with three vector-borne pathogens: B. canis vogeli, E. canis and L. infantum. Overall, L. infantum was found in seven (16%), E. canis in two (4%), and H. canis in one (2%) out of the 45 dogs with babesiosis. Almost 90% of the 45 cases of canine babesiosis were diagnosed in the colder months of October (18%), November (27%), December (20%), February (13%) and March (9%). Co-infections were detected in February, March, April, May, October and November. Twenty-two (50%) out of 44 dogs infected with B. canis were found infested by ticks including Dermacentor spp., Ixodes spp. and Rhipicephalus sanguineus. Mortality (9%) included two co-infected dogs that died spontaneously and two with single infections that were euthanized. Conclusions Babesia canis canis is the main etiological agent of canine babesiosis in northern Portugal. A higher sensitivity of Babesia spp. detection was obtained with PCR assays, compared to the observation of blood smears. Twenty percent of the dogs were co-infected with L. infantum

  3. Canine babesiosis in northern Portugal and molecular characterization of vector-borne co-infections

    Directory of Open Access Journals (Sweden)

    Machado João

    2010-04-01

    Full Text Available Abstract Background Protozoa and bacteria transmitted by arthropods, including ticks and phlebotomine sand flies, may cause a wide range of canine vector-borne diseases. Dogs can be simultaneously or sequentially infected with multiple pathogens. Canine babesiosis caused by Babesia canis canis and Babesia canis vogeli is known to occur in Portugal. This study assessed, by means of blood smear examination, PCR and DNA nucleotide sequencing, the presence of Babesia spp. and co-infecting agents Leishmania, Anaplasma/Ehrlichia and Hepatozoon in 45 dogs from northern Portugal clinically suspected of babesiosis. Results Forty-four dogs (98% had infection with B. canis canis and one with B. canis vogeli. Co-infections were detected in nine animals (20%. Eight dogs were found infected with two vector-borne agents: six with B. canis canis and Leishmania infantum; one with B. canis canis and Ehrlichia canis; and one with B. canis canis and Hepatozoon canis. Another dog was infected with three vector-borne pathogens: B. canis vogeli, E. canis and L. infantum. Overall, L. infantum was found in seven (16%, E. canis in two (4%, and H. canis in one (2% out of the 45 dogs with babesiosis. Almost 90% of the 45 cases of canine babesiosis were diagnosed in the colder months of October (18%, November (27%, December (20%, February (13% and March (9%. Co-infections were detected in February, March, April, May, October and November. Twenty-two (50% out of 44 dogs infected with B. canis were found infested by ticks including Dermacentor spp., Ixodes spp. and Rhipicephalus sanguineus. Mortality (9% included two co-infected dogs that died spontaneously and two with single infections that were euthanized. Conclusions Babesia canis canis is the main etiological agent of canine babesiosis in northern Portugal. A higher sensitivity of Babesia spp. detection was obtained with PCR assays, compared to the observation of blood smears. Twenty percent of the dogs were co

  4. A GEOSPATIAL ANALYSIS OF THE RELATIONSHIP BETWEEN ENVIRONMENTAL DRIVERS AND VECTOR-BORNE DISEASES

    Directory of Open Access Journals (Sweden)

    MARIA IOANA VLAD-ȘANDRU

    2015-10-01

    Full Text Available A Geospatial Analysis of the Relationship between Environmental Drivers and Vector-Borne Diseases. Human health is profoundly affected by weather and climate. Environmental health is becoming a major preoccupation on a world-wide scale; there is a close correlation between a population’s state of health and the quality of its environment, considering many infectious diseases are at least partly dependent on environmental factors. When we talk about the environment, we realize that it includes and affects fields of action from our daily life. Earth observation from space, with validation from in situ observations, provide a greater understanding of the environment and enable us to monitor and predict key environmental phenomena and events that can affect our livelihoods and health. Even thought, the use of Earth observation is growing in usefulness for a wide variety of uses, it is extremely unlikely that Earth Observation will be able to detect infectious diseases directly. Instead, Earth observation can be used to detect high NDVI index (and possibly attribute the high surface chlorophyll concentration to a particular disease, and help predict the movement of the agents carrying vector-borne disease. Many diseases need certain temperature and moisture conditions to breed. The primary objective of analyzing environmental health risk and vulnerabilities is to support the Development Regions to strengthen their capacity to assess, visualize and analyze health risks and incorporate the results of this analysis in a health risk map for disaster risk reduction, emergency preparedness and response plans. At the same time, such an analysis applied in health, allows starting the collection and homogenization of baseline data, information and maps to help health authorities and decision makers to take informed decisions in times of crises. Informational Health Platform would be used for the integration of data coming from different sources in order to

  5. Prevalence of select vector-borne disease agents in owned dogs of Ghana

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    Lorelei L. Clarke

    2014-09-01

    Full Text Available Ticks, sera and ethylenediaminetetraacetic acid (EDTA blood were collected from dogs evaluated at the Amakom Veterinary Clinic in Kumasi, Ghana. Sera were evaluated for Dirofilaria immitis antigen and antibodies against Borrelia burgdorferi, Anaplasma phagocytophilum and Ehrlichia canis. Conventional polymerase chain reaction assays designed to amplify the deoxyribonucleic acid (DNA ofEhrlichia spp. or Anaplasma spp. or Neorickettsia spp. or Wolbachia spp., Babesia spp., Rickettsia spp., Hepatozoon spp., Bartonella spp. and the haemoplasmas were performed on DNA extracted from EDTA blood and all positive amplicons were sequenced. This small survey shows that the following vector-borne pathogens are present in urban Ghanian dogs: Ehrlichia canis, Hepatozoon canis,Dirofilaria immitis and Anaplasma platys. Bartonella henselae was isolated from ticks but not from the dogs.

  6. Medical Entomology: A Reemerging Field of Research to Better Understand Vector-Borne Infectious Diseases.

    Science.gov (United States)

    Laroche, Maureen; Bérenger, Jean-Michel; Delaunay, Pascal; Charrel, Remi; Pradines, Bruno; Berger, Franck; Ranque, Stéphane; Bitam, Idir; Davoust, Bernard; Raoult, Didier; Parola, Philippe

    2017-08-15

    In the last decade, the Chikungunya and Zika virus outbreaks have turned public attention to the possibility of the expansion of vector-borne infectious diseases worldwide. Medical entomology is focused on the study of arthropods involved in human health. We review here some of the research approaches taken by the medical entomology team of the University Hospital Institute (UHI) Méditerranée Infection of Marseille, France, with the support of recent or representative studies. We propose our approaches to technical innovations in arthropod identification and the detection of microorganisms in arthropods, the use of arthropods as epidemiological or diagnostic tools, entomological investigations around clinical cases or within specific populations, and how we have developed experimental models to decipher the interactions between arthropods, microorganisms, and humans. © 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.

  7. Eurasian golden jackal as host of canine vector-borne protists.

    Science.gov (United States)

    Mitková, Barbora; Hrazdilová, Kristýna; D'Amico, Gianluca; Duscher, Georg Gerhard; Suchentrunk, Franz; Forejtek, Pavel; Gherman, Călin Mircea; Matei, Ioana Adriana; Ionică, Angela Monica; Daskalaki, Aikaterini Alexandra; Mihalca, Andrei Daniel; Votýpka, Jan; Hulva, Pavel; Modrý, David

    2017-04-14

    Jackals are medium-sized canids from the wolf-like clade, exhibiting a unique combination of ancestral morphotypes, broad trophic niches, and close phylogenetic relationships with the wolf and dog. Thus, they represent a potential host of several pathogens with diverse transmission routes. Recently, populations of the Eurasian golden jackal Canis aureus have expanded into the Western Palaearctic, including most of Europe. The aim of our study was to examine Eurasian golden jackals from Romania, Czech Republic and Austria for a wide spectrum of vector-borne protists and to evaluate the role of this species as a reservoir of disease for domestic dogs and/or humans. Diagnostic polymerase chain reaction (PCR) DNA amplifications revealed 70% of jackals to be positive for Hepatozoon, 12.5% positive for piroplasms, and one individual positive for Leishmania infantum. Phylogenetic analyses of partial 18S rDNA sequences invariably placed sequenced isolates of Hepatozoon into the H. canis clade. For piroplasms, both the 18S and cox1 sequences obtained confirmed the presence of Babesia canis and "Theileria annae" in 5 and 2 individuals, respectively, providing the first records of these two piroplasmids in Eurasian golden jackals. A single animal from Dolj County (Romania) was PCR-positive for L. infantum, as confirmed also by sequencing of ITS1-5.8S. Apparently, expanding populations of jackals can play a significant role in spreading and maintaining new Babesia canis foci in Central Europe. The role of jackals in the epidemiology of "Theileria annae" and H. canis is probably similar to that of red foxes and should be taken into account in further research on these parasites. Also the presence of L. infantum deserves attention. Our study confirms that once established, the populations of Eurasian golden jackals constitute natural reservoirs for many canine vector-borne diseases, analogous to the role of the coyotes in North America.

  8. Wildlife reservoirs for vector-borne canine, feline and zoonotic infections in Austria

    Science.gov (United States)

    Duscher, Georg G.; Leschnik, Michael; Fuehrer, Hans-Peter; Joachim, Anja

    2014-01-01

    Austria's mammalian wildlife comprises a large variety of species, acting and interacting in different ways as reservoir and intermediate and definitive hosts for different pathogens that can be transmitted to pets and/or humans. Foxes and other wild canids are responsible for maintaining zoonotic agents, e.g. Echinococcus multilocularis, as well as pet-relevant pathogens, e.g. Hepatozoon canis. Together with the canids, and less commonly felids, rodents play a major role as intermediate and paratenic hosts. They carry viruses such as tick-borne encephalitis virus (TBEV), bacteria including Borrelia spp., protozoa such as Toxoplasma gondii, and helminths such as Toxocara canis. The role of wild ungulates, especially ruminants, as reservoirs for zoonotic disease on the other hand seems to be negligible, although the deer filaroid Onchocerca jakutensis has been described to infect humans. Deer may also harbour certain Anaplasma phagocytophilum strains with so far unclear potential to infect humans. The major role of deer as reservoirs is for ticks, mainly adults, thus maintaining the life cycle of these vectors and their distribution. Wild boar seem to be an exception among the ungulates as, in their interaction with the fox, they can introduce food-borne zoonotic agents such as Trichinella britovi and Alaria alata into the human food chain. PMID:25830102

  9. Recent Weather Extremes and Impacts on Agricultural Production and Vector-Borne Disease Outbreak Patterns

    Science.gov (United States)

    Anyamba, Assaf; Small, Jennifer L.; Britch, Seth C.; Tucker, Compton J.; Pak, Edwin W.; Reynolds, Curt A.; Crutchfield, James; Linthicum, Kenneth J.

    2014-01-01

    We document significant worldwide weather anomalies that affected agriculture and vector-borne disease outbreaks during the 2010-2012 period. We utilized 2000-2012 vegetation index and land surface temperature data from NASA's satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS) to map the magnitude and extent of these anomalies for diverse regions including the continental United States, Russia, East Africa, Southern Africa, and Australia. We demonstrate that shifts in temperature and/or precipitation have significant impacts on vegetation patterns with attendant consequences for agriculture and public health. Weather extremes resulted in excessive rainfall and flooding as well as severe drought, which caused,10 to 80% variation in major agricultural commodity production (including wheat, corn, cotton, sorghum) and created exceptional conditions for extensive mosquito-borne disease outbreaks of dengue, Rift Valley fever, Murray Valley encephalitis, and West Nile virus disease. Analysis of MODIS data provided a standardized method for quantifying the extreme weather anomalies observed during this period. Assessments of land surface conditions from satellite-based systems such as MODIS can be a valuable tool in national, regional, and global weather impact determinations.

  10. Recent weather extremes and impacts on agricultural production and vector-borne disease outbreak patterns.

    Directory of Open Access Journals (Sweden)

    Assaf Anyamba

    Full Text Available We document significant worldwide weather anomalies that affected agriculture and vector-borne disease outbreaks during the 2010-2012 period. We utilized 2000-2012 vegetation index and land surface temperature data from NASA's satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS to map the magnitude and extent of these anomalies for diverse regions including the continental United States, Russia, East Africa, Southern Africa, and Australia. We demonstrate that shifts in temperature and/or precipitation have significant impacts on vegetation patterns with attendant consequences for agriculture and public health. Weather extremes resulted in excessive rainfall and flooding as well as severe drought, which caused ∼10 to 80% variation in major agricultural commodity production (including wheat, corn, cotton, sorghum and created exceptional conditions for extensive mosquito-borne disease outbreaks of dengue, Rift Valley fever, Murray Valley encephalitis, and West Nile virus disease. Analysis of MODIS data provided a standardized method for quantifying the extreme weather anomalies observed during this period. Assessments of land surface conditions from satellite-based systems such as MODIS can be a valuable tool in national, regional, and global weather impact determinations.

  11. Continental-scale, data-driven predictive assessment of eliminating the vector-borne disease, lymphatic filariasis, in sub-Saharan Africa by 2020.

    Science.gov (United States)

    Michael, Edwin; Singh, Brajendra K; Mayala, Benjamin K; Smith, Morgan E; Hampton, Scott; Nabrzyski, Jaroslaw

    2017-09-27

    There are growing demands for predicting the prospects of achieving the global elimination of neglected tropical diseases as a result of the institution of large-scale nation-wide intervention programs by the WHO-set target year of 2020. Such predictions will be uncertain due to the impacts that spatial heterogeneity and scaling effects will have on parasite transmission processes, which will introduce significant aggregation errors into any attempt aiming to predict the outcomes of interventions at the broader spatial levels relevant to policy making. We describe a modeling platform that addresses this problem of upscaling from local settings to facilitate predictions at regional levels by the discovery and use of locality-specific transmission models, and we illustrate the utility of using this approach to evaluate the prospects for eliminating the vector-borne disease, lymphatic filariasis (LF), in sub-Saharan Africa by the WHO target year of 2020 using currently applied or newly proposed intervention strategies. METHODS AND RESULTS: We show how a computational platform that couples site-specific data discovery with model fitting and calibration can allow both learning of local LF transmission models and simulations of the impact of interventions that take a fuller account of the fine-scale heterogeneous transmission of this parasitic disease within endemic countries. We highlight how such a spatially hierarchical modeling tool that incorporates actual data regarding the roll-out of national drug treatment programs and spatial variability in infection patterns into the modeling process can produce more realistic predictions of timelines to LF elimination at coarse spatial scales, ranging from district to country to continental levels. Our results show that when locally applicable extinction thresholds are used, only three countries are likely to meet the goal of LF elimination by 2020 using currently applied mass drug treatments, and that switching to more

  12. Network-level reproduction number and extinction threshold for vector-borne diseases.

    Science.gov (United States)

    Xue, Ling; Scoglio, Caterina

    2015-06-01

    The basic reproduction number of deterministic models is an essential quantity to predict whether an epidemic will spread or not. Thresholds for disease extinction contribute crucial knowledge of disease control, elimination, and mitigation of infectious diseases. Relationships between basic reproduction numbers of two deterministic network-based ordinary differential equation vector-host models, and extinction thresholds of corresponding stochastic continuous-time Markov chain models are derived under some assumptions. Numerical simulation results for malaria and Rift Valley fever transmission on heterogeneous networks are in agreement with analytical results without any assumptions, reinforcing that the relationships may always exist and proposing a mathematical problem for proving existence of the relationships in general. Moreover, numerical simulations show that the basic reproduction number does not monotonically increase or decrease with the extinction threshold. Consistent trends of extinction probability observed through numerical simulations provide novel insights into mitigation strategies to increase the disease extinction probability. Research findings may improve understandings of thresholds for disease persistence in order to control vector-borne diseases.

  13. Incidence of Vector-borne Disease and Climate Change: A Study in Semi-arid Algeria

    Science.gov (United States)

    Blakey, T.; Bounoua, L.

    2012-12-01

    Leishmaniases are among the most important emerging and resurging vector-borne diseases, second only to malaria in terms of the number of affected people. Leishmaniases are endemic in 88 countries worldwide and threaten about 350 million people (WHO, 2007). Since the first reported case of zoonotic cutaneous leishmaniasis (ZCL) in Saida, Algeria in 1991, 1,275 cases have been recorded (Makhlouf & Houti, 2010) with the vast majority of study-area cases (99%) reported between the years of 2000 and 2009. An investigation of potential climatic indicators for the apparent shift in disease prevalence was conducted by comparing anomalies in the climate data specific to the local pathogen cycle. It was determined that long term climate trends have resulted in conditions that promote the prevalence of ZCL. Increased precipitation have resulted in greater vegetation and promoted host and vector population growth through a trophic cascade. Increased minimum temperatures have lengthened the annual duration of sandfly activity. Short term variations in maximum temperatures, however show a correlation with disease suppression in the subsequent years. These findings indicate a potential to forecast the risk of ZCL infection through models of the trophic cascade and sandfly population growth.

  14. WNV infection - an emergent vector borne viral infection in Serbia: Current situation

    Directory of Open Access Journals (Sweden)

    Petrović Tamaš

    2015-01-01

    Full Text Available West Nile virus (WNV is a neurovirulent mosquito-borne Flavivirus with zoonotic potential. Virus is maintained in nature in an enzootic transmission cycle between avian hosts and mosquito vectors, but occasionally infects other vertebrates. The infection in horses and humans can be asymptomatic or it can have different clinical manifestations ranging from light febrile diseases to fatal meningoencephalitis. Recently, the number, frequency and severity of outbreaks with neurological consequences for birds, humans and horses have increased dramatically throughout central and south Europe, including Serbia, posing a serious veterinary and public health problem. The emergency of WNV infections in Serbia is described through the current epidemiology situation based on recent data on the incidence of WNV infection among virus natural hosts and vectors; sentinel (horses and other animal species, and in human population. The results of the WNV serology studies conducted on horse blood samples collected in different occasions during the last six years, and the results of the serology studies conducted among other animal species like pigs, wild boars, roe deer and dogs in Serbia are presented and discussed. Also, the results of the first studies on WNV presence in mosquito vectors and in wild birds as virus natural hosts in Serbia are presented and analyzed. In addition, the data on the WNV serology studies conducted in human population in Serbia in the last few years, and the existing data of WNV outbreaks in 2012 and 2013 are included. Regarding the existing knowledge on WNV epidemiology situation, the crucial role of veterinary service in early detection of WNV presence and ongoing national program of WNV surveillance in sentinel animals, mosquitoes and wild birds are discussed.

  15. Surveillance of vector-borne diseases in Germany: trends and challenges in the view of disease emergence and climate change.

    Science.gov (United States)

    Jansen, Andreas; Frank, Christina; Koch, Judith; Stark, Klaus

    2008-12-01

    The changing epidemiology of vector-borne diseases represents a growing threat to human health. Contemporary surveillance systems have to adapt to these changes. We describe temporal trends and geographic origins of vector-borne diseases in Germany with regard to strengths of existing disease surveillance and to areas marked for improvement. We focused on hantavirus infection (endemic in Germany), chikungunya fever (recently emerging in Europe) and dengue fever (imported from tropical regions), representing important subgroups of vector-borne infections. Routine surveillance data on demographics, origin of infection and the date of reporting were analysed. From 2001 through 2007, 3,005 symptomatic hantavirus infections, and 85 cases of chikungunya fever were reported, similarly 1,048 cases of dengue fever in 2002 through 2007. The geographic origin of hantavirus infection was reported for 95.5% of all cases (dengue virus, 98.4%; chikungunya virus, 100%). Hantavirus infections were acquired in Germany in 97.6% of cases (n = 2800). In 2007, there was a marked increase of hantavirus cases, mainly in areas known to be endemic for hantavirus. In 2006, imported cases of chikungunya fever primarily returned from several islands of the Indian Ocean, while the majority of imported cases in 2007 came from India. The reported number of dengue fever cases have increased since 2004. Thailand contributed the largest proportion of cases (17-43% in individual years), followed by India, Brazil and Indonesia. Surveillance of notifiable vector-borne diseases in Germany is able to timely detect spatial and temporal changes of autochthonous an imported infections. Geographic and temporal data obtained by routine surveillance served as a basis for public health recommendations. In addition to surveillance of vector-borne infections in humans, nationwide monitoring programs and inventory techniques for emerging and reemerging vectors and for wildlife disease are warranted.

  16. Mapping the basic reproduction number (Ro) for vector-borne diseases: A case study on bluetongue virus.

    NARCIS (Netherlands)

    Hartemink, N.; Purse, B.V.; Meiswinkel, R.; Brown, H.E.; Koeijer, de A.A.; Elbers, A.R.W.; Boender, G.J.; Rogers, D.J.; Heesterbeek, J.A.P.

    2009-01-01

    Geographical maps indicating the value of the basic reproduction number, R0, can be used to identify areas of higher risk for an outbreak after an introduction. We develop a methodology to create R0 maps for vector-borne diseases, using bluetongue virus as a case study. This method provides a tool

  17. Global trends in the production and use of DDT for control of malaria and other vector-borne diseases

    NARCIS (Netherlands)

    Berg, van den Henk; Manuweera, Gamini; Konradsen, Flemming

    2017-01-01

    Background: DDT was among the initial persistent organic pollutants listed under the Stockholm Convention and continues to be used for control of malaria and other vector-borne diseases in accordance with its provisions on acceptable purposes. Trends in the production and use of DDT were

  18. Risk based surveillance for vector-borne diseases in horses : combining multiple sources of evidence to improve decision making

    NARCIS (Netherlands)

    Faverjon, Céline

    2017-01-01

    Emerging vector-borne diseases are a growing concern, especially for horse populations, which are at particular risk for disease spread. In general, horses travel widely and frequently and, despite the health and economic impacts of equine diseases, effective health regulations and biosecurity

  19. R0-modeling as a tool for early warning and surveillance of exotic vector borne diseases in Denmark

    DEFF Research Database (Denmark)

    Bødker, Rene

    2011-01-01

    for predicting permanent establishment of presently exotic diseases, mean temperatures may not predict the true potential for local spread and limited outbreaks resulting from accidental introductions in years with temporary periods of warm weather. DTU-Veterinary Institute is developing a system for continuous...... a truly risk based surveillance system for insect borne diseases. R0 models for many vector borne diseases are simple and the available estimates of model parameters like vector densities and survival rates may be uncertain. The quantitative value of R0 estimated from such models is therefore likely......Modeling the potential transmission intensity of insect borne diseases with climate driven R0 process models is frequently used to assess the potential for veterinary and human infections to become established in non endemic areas. Models are often based on mean temperatures of an arbitrary time...

  20. Internet-based biosurveillance methods for vector-borne diseases: Are they novel public health tools or just novelties?

    Science.gov (United States)

    Pollett, Simon; Althouse, Benjamin M; Forshey, Brett; Rutherford, George W; Jarman, Richard G

    2017-11-01

    Internet-based surveillance methods for vector-borne diseases (VBDs) using "big data" sources such as Google, Twitter, and internet newswire scraping have recently been developed, yet reviews on such "digital disease detection" methods have focused on respiratory pathogens, particularly in high-income regions. Here, we present a narrative review of the literature that has examined the performance of internet-based biosurveillance for diseases caused by vector-borne viruses, parasites, and other pathogens, including Zika, dengue, other arthropod-borne viruses, malaria, leishmaniasis, and Lyme disease across a range of settings, including low- and middle-income countries. The fundamental features, advantages, and drawbacks of each internet big data source are presented for those with varying familiarity of "digital epidemiology." We conclude with some of the challenges and future directions in using internet-based biosurveillance for the surveillance and control of VBD.

  1. Internet-based biosurveillance methods for vector-borne diseases: Are they novel public health tools or just novelties?

    Directory of Open Access Journals (Sweden)

    Simon Pollett

    2017-11-01

    Full Text Available Internet-based surveillance methods for vector-borne diseases (VBDs using "big data" sources such as Google, Twitter, and internet newswire scraping have recently been developed, yet reviews on such "digital disease detection" methods have focused on respiratory pathogens, particularly in high-income regions. Here, we present a narrative review of the literature that has examined the performance of internet-based biosurveillance for diseases caused by vector-borne viruses, parasites, and other pathogens, including Zika, dengue, other arthropod-borne viruses, malaria, leishmaniasis, and Lyme disease across a range of settings, including low- and middle-income countries. The fundamental features, advantages, and drawbacks of each internet big data source are presented for those with varying familiarity of "digital epidemiology." We conclude with some of the challenges and future directions in using internet-based biosurveillance for the surveillance and control of VBD.

  2. International network for capacity building for the control of emerging viral vector-borne zoonotic diseases: ARBO-ZOONET.

    Science.gov (United States)

    Ahmed, J; Bouloy, M; Ergonul, O; Fooks, Ar; Paweska, J; Chevalier, V; Drosten, C; Moormann, R; Tordo, N; Vatansever, Z; Calistri, P; Estrada-Pena, A; Mirazimi, A; Unger, H; Yin, H; Seitzer, U

    2009-03-26

    Arboviruses are arthropod-borne viruses, which include West Nile fever virus (WNFV), a mosquito-borne virus, Rift Valley fever virus (RVFV), a mosquito-borne virus, and Crimean-Congo haemorrhagic fever virus (CCHFV), a tick-borne virus. These arthropod-borne viruses can cause disease in different domestic and wild animals and in humans, posing a threat to public health because of their epidemic and zoonotic potential. In recent decades, the geographical distribution of these diseases has expanded. Outbreaks of WNF have already occurred in Europe, especially in the Mediterranean basin. Moreover, CCHF is endemic in many European countries and serious outbreaks have occurred, particularly in the Balkans, Turkey and Southern Federal Districts of Russia. In 2000, RVF was reported for the first time outside the African continent, with cases being confirmed in Saudi Arabia and Yemen. This spread was probably caused by ruminant trade and highlights that there is a threat of expansion of the virus into other parts of Asia and Europe. In the light of global warming and globalisation of trade and travel, public interest in emerging zoonotic diseases has increased. This is especially evident regarding the geographical spread of vector-borne diseases. A multi-disciplinary approach is now imperative, and groups need to collaborate in an integrated manner that includes vector control, vaccination programmes, improved therapy strategies, diagnostic tools and surveillance, public awareness, capacity building and improvement of infrastructure in endemic regions.

  3. Surveillance of vector-borne pathogens under imperfect detection: lessons from Chagas disease risk (mis)measurement.

    Science.gov (United States)

    Minuzzi-Souza, Thaís Tâmara Castro; Nitz, Nadjar; Cuba, César Augusto Cuba; Hagström, Luciana; Hecht, Mariana Machado; Santana, Camila; Ribeiro, Marcelle; Vital, Tamires Emanuele; Santalucia, Marcelo; Knox, Monique; Obara, Marcos Takashi; Abad-Franch, Fernando; Gurgel-Gonçalves, Rodrigo

    2018-01-09

    Vector-borne pathogens threaten human health worldwide. Despite their critical role in disease prevention, routine surveillance systems often rely on low-complexity pathogen detection tests of uncertain accuracy. In Chagas disease surveillance, optical microscopy (OM) is routinely used for detecting Trypanosoma cruzi in its vectors. Here, we use replicate T. cruzi detection data and hierarchical site-occupancy models to assess the reliability of OM-based T. cruzi surveillance while explicitly accounting for false-negative and false-positive results. We investigated 841 triatomines with OM slides (1194 fresh, 1192 Giemsa-stained) plus conventional (cPCR, 841 assays) and quantitative PCR (qPCR, 1682 assays). Detections were considered unambiguous only when parasitologists unmistakably identified T. cruzi in Giemsa-stained slides. qPCR was >99% sensitive and specific, whereas cPCR was ~100% specific but only ~55% sensitive. In routine surveillance, examination of a single OM slide per vector missed ~50-75% of infections and wrongly scored as infected ~7% of the bugs. qPCR-based and model-based infection frequency estimates were nearly three times higher, on average, than OM-based indices. We conclude that the risk of vector-borne Chagas disease may be substantially higher than routine surveillance data suggest. The hierarchical modelling approach we illustrate can help enhance vector-borne disease surveillance systems when pathogen detection is imperfect.

  4. Protection of Military Personnel Against Vector-Borne Diseases: A Review of Collaborative Work of the Australian and US Military Over the Last 30 Years.

    Science.gov (United States)

    Frances, Stephen P; Edstein, Michael D; Debboun, Mustapha; Shanks, G Dennis

    2016-01-01

    Australian and US military medical services have collaborated since World War II to minimize vector-borne diseases such as malaria, dengue, and scrub typhus. In this review, collaboration over the last 30 years is discussed. The collaborative projects and exchange scientist programs have resulted in mutually beneficial outcomes in the fields of drug development and personal protection measures against vector-borne diseases.

  5. Identification of vector-borne pathogens in dogs and cats from Southern Brazil.

    Science.gov (United States)

    Malheiros, J; Costa, M M; do Amaral, R B; de Sousa, K C M; André, M R; Machado, R Z; Vieira, M I B

    2016-07-01

    Dogs and cats are often infected with vector-borne pathogens and play a crucial role as reservoirs and hosts in their life cycles. The aim of the present study was to investigate the occurrence of vector-borne pathogens among dogs and cats in the northwestern region of Rio Grande do Sul (RS) State, Brazil. One hundred and ten blood samples were collected from dogs (n=80) and cats (n=30). Laboratory analysis were carried out through stained blood smears, indirect enzyme-linked immunosorbent assay (ELISA) for Babesia vogeli and Ehrlichia canis (only for dogs) and polymerase chain reaction (PCR) aiming the detection of pathogens. The following pathogens were screened by PCR among dogs and cats: Babesia spp. and Hepatozoon spp. (18S rRNA gene), Anaplasma spp. (16S rRNA gene), and Ehrlichia spp. (dsb gene for dogs and 16S rRNA gene for cats) and Bartonella spp. (nuoG gene only for cats). Using blood smears structures morphologically compatible with piroplasms were found in 5.45% (6/110) of the samples. Anti-B. vogeli and anti-E. canis antibodies were detected in 91% (73/80) and 9% (7/80) of the dogs, respectively. All the seropositive dogs to E. canis were also to B. vogeli. Nineteen (17.3%) animals were positive to hemoparasites by PCR. After sequencing Rangelia vitalii 6/80 (7.5%), B. vogeli 3/80 (4%), Hepatozoon spp. 1/80 (1%), and Anaplasma spp. 1/80 (1%) were found in the dogs, and B. vogeli 2/30 (7%) and Bartonella spp. 6/30 (20%) were detected in the screened cats. No sample was positive for genes dsb and 16S rRNA of Ehrlichia spp. Only those animals which were positive for R. vitalii showed findings compatible with rangeliosis, such as anemia (100%), thrombocytopenia (67%), jaundice (50%), external bleeding (50%), and anorexia (50%). This is the first time that B. vogeli detected among cats in Southern Brazil. Copyright © 2016 Elsevier GmbH. All rights reserved.

  6. Multi-disease data management system platform for vector-borne diseases.

    Directory of Open Access Journals (Sweden)

    Lars Eisen

    2011-03-01

    Full Text Available Emerging information technologies present new opportunities to reduce the burden of malaria, dengue and other infectious diseases. For example, use of a data management system software package can help disease control programs to better manage and analyze their data, and thus enhances their ability to carry out continuous surveillance, monitor interventions and evaluate control program performance.We describe a novel multi-disease data management system platform (hereinafter referred to as the system with current capacity for dengue and malaria that supports data entry, storage and query. It also allows for production of maps and both standardized and customized reports. The system is comprised exclusively of software components that can be distributed without the user incurring licensing costs. It was designed to maximize the ability of the user to adapt the system to local conditions without involvement of software developers. Key points of system adaptability include 1 customizable functionality content by disease, 2 configurable roles and permissions, 3 customizable user interfaces and display labels and 4 configurable information trees including a geographical entity tree and a term tree. The system includes significant portions of functionality that is entirely or in large part re-used across diseases, which provides an economy of scope as new diseases downstream are added to the system at decreased cost.We have developed a system with great potential for aiding disease control programs in their task to reduce the burden of dengue and malaria, including the implementation of integrated vector management programs. Next steps include evaluations of operational implementations of the current system with capacity for dengue and malaria, and the inclusion in the system platform of other important vector-borne diseases.

  7. Prevalence and Geographic Distribution of Vector-Borne Pathogens in Apparently Healthy Dogs in Croatia.

    Science.gov (United States)

    Mrljak, Vladimir; Kuleš, Josipa; Mihaljević, Željko; Torti, Marin; Gotić, Jelena; Crnogaj, Martina; Živičnjak, Tatjana; Mayer, Iva; Šmit, Iva; Bhide, Mangesh; Barić Rafaj, Renata

    2017-06-01

    Vector-borne pathogens (VBPs) are a group of globally extended and quickly spreading pathogens that are transmitted by various arthropod vectors. The aim of the present study was to investigate the seroprevalence against Babesia canis, Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Leishmania infantum, Dirofilaria immitis, and Ehrlichia canis in dogs in Croatia. We investigated 435 randomly selected apparently healthy dogs in 13 different locations of Croatia for antibodies to B. canis by indirect immunofluorescence using a commercial IFA IgG Antibody Kit. All samples were also tested for qualitative detection of D. immitis antigen and for antibodies to A. phagocytophilum, B. burgdorferi sensu lato, L. infantum, and E. canis with two point-of-care assays. Overall, 112 dogs (25.74%, 95% confidence interval [CI] 21.70-30.12) were serologically positive for one or more of the pathogens. B. canis was the most prevalent pathogen (20.00%, 95% CI 16.34-24.07), followed by A. phagocytophilum (6.21%, 95% CI 4.12-8.90), L. infantum, (1.38%, 95% CI 0.51-2.97), and B. burgdorferi sensu lato (0.69%, 95% CI 0.01-2.00). The lowest seroprevalence was for D. immitis and E. canis (0.46%, 95% CI 0.01-1.65). Coinfection was determined in 12 dogs (2.76%, 95% CI 1.43-4.77), of which 10 were positive to two pathogens (7 with B. canis and A. phagocytophilum and 1 B. canis with B. burgdorferi sensu lato or L. infantum or E. canis). One dog was positive to three pathogens and another dog to four pathogens. Seroprevalence for babesia was age, breed, and lifestyle/use dependent. Purebred dogs had almost half the chance of developing disease than crossbred (OR = 0.58, p Croatia. Some of these VBPs are zoonotic and represent a potential risk to public health.

  8. A review of trends in the distribution of vector-borne diseases: is international trade contributing to their spread?

    Science.gov (United States)

    de La Rocque, S; Balenghien, T; Halos, L; Dietze, K; Claes, F; Ferrari, G; Guberti, V; Slingenbergh, J

    2011-04-01

    It is difficult to determine the part that international trade has played in the expansion of vector-borne diseases, because of the multitude of factors that affect the transformation of habitats and the interfaces between vectors and hosts. The introduction of pathogens through trade in live animals or products of animal origin, as well as the arrival of arthropod vectors, is probably quite frequent but the establishment of an efficient transmission system that develops into a disease outbreak remains the exception. In this paper, based on well-documented examples, the authors review the ecological and epidemiological characteristics of vector-borne diseases that may have been affected in their spread and change of distribution by international trade. In addition, they provide a detailed analysis of the risks associated with specific trade routes and recent expansions of vector populations. Finally, the authors highlight the importance, as well as the challenges, of preventive surveillance and regulation. The need for improved monitoring of vector populations and a readiness to face unpredictable epidemiological events are also emphasised, since this will require rapid reaction, not least in the regulatory context.

  9. The role of the ratio of vector and host densities in the evolution of transmission modes in vector-borne diseases. The example of sylvatic Trypanosoma cruzi.

    Science.gov (United States)

    Pelosse, Perrine; Kribs-Zaleta, Christopher M

    2012-11-07

    Pathogens may use different routes of transmission to maximize their spread among host populations. Theoretical and empirical work conducted on directly transmitted diseases suggest that horizontal (i.e., through host contacts) and vertical (i.e., from mother to offspring) transmission modes trade off, on the ground that highly virulent pathogens, which produce larger parasite loads, are more efficiently transmitted horizontally, and that less virulent pathogens, which impair host fitness less significantly, are better transmitted vertically. Other factors than virulence such as host density could also select for different transmission modes, but they have barely been studied. In vector-borne diseases, pathogen transmission rate is strongly affected by host-vector relative densities and by processes of saturation in contacts between hosts and vectors. The parasite Trypanosoma cruzi which is transmitted by triatomine bugs to several vertebrate hosts is responsible for Chagas' disease in Latin America. It is also widespread in sylvatic cycles in the southeastern U.S. in which it typically induces no mortality costs to its customary hosts. Besides classical transmission via vector bites, alternative ways to generate infections in hosts such as vertical and oral transmission (via the consumption of vectors by hosts) have been reported in these cycles. The two major T. cruzi strains occurring in the U.S. seem to exhibit differential efficiencies at vertical and classical horizontal transmissions. We investigated whether the vector-host ratio affects the outcome of the competition between the two parasite strains using an epidemiological two-strain model considering all possible transmission routes for sylvatic T. cruzi. We were able to show that the vector-host ratio influences the evolution of transmission modes providing that oral transmission is included in the model as a possible transmission mode, that oral and classical transmissions saturate at different vector

  10. Status of pesticide management in the practice of vector control: a global survey in countries at risk of malaria or other major vector-borne diseases

    Directory of Open Access Journals (Sweden)

    Tan Soo

    2011-05-01

    Full Text Available Abstract Background It is critical that vector control pesticides are used for their acceptable purpose without causing adverse effects on health and the environment. This paper provides a global overview of the current status of pesticides management in the practice of vector control. Methods A questionnaire was distributed to WHO member states and completed either by the director of the vector-borne disease control programme or by the national manager for vector control. In all, 113 countries responded to the questionnaire (80% response rate, representing 94% of the total population of the countries targeted. Results Major gaps were evident in countries in pesticide procurement practices, training on vector control decision making, certification and quality control of pesticide application, monitoring of worker safety, public awareness programmes, and safe disposal of pesticide-related waste. Nevertheless, basic conditions of policy and coordination have been established in many countries through which the management of vector control pesticides could potentially be improved. Most countries responded that they have adopted relevant recommendations by the WHO. Conclusions Given the deficiencies identified in this first global survey on public health pesticide management and the recent rise in pesticide use for malaria control, the effectiveness and safety of pesticide use are being compromised. This highlights the urgent need for countries to strengthen their capacity on pesticide management and evidence-based decision making within the context of an integrated vector management approach.

  11. Status of pesticide management in the practice of vector control: a global survey in countries at risk of malaria or other major vector-borne diseases.

    Science.gov (United States)

    van den Berg, Henk; Hii, Jeffrey; Soares, Agnes; Mnzava, Abraham; Ameneshewa, Birkinesh; Dash, Aditya P; Ejov, Mikhail; Tan, Soo Hian; Matthews, Graham; Yadav, Rajpal S; Zaim, Morteza

    2011-05-14

    It is critical that vector control pesticides are used for their acceptable purpose without causing adverse effects on health and the environment. This paper provides a global overview of the current status of pesticides management in the practice of vector control. A questionnaire was distributed to WHO member states and completed either by the director of the vector-borne disease control programme or by the national manager for vector control. In all, 113 countries responded to the questionnaire (80% response rate), representing 94% of the total population of the countries targeted. Major gaps were evident in countries in pesticide procurement practices, training on vector control decision making, certification and quality control of pesticide application, monitoring of worker safety, public awareness programmes, and safe disposal of pesticide-related waste. Nevertheless, basic conditions of policy and coordination have been established in many countries through which the management of vector control pesticides could potentially be improved. Most countries responded that they have adopted relevant recommendations by the WHO. Given the deficiencies identified in this first global survey on public health pesticide management and the recent rise in pesticide use for malaria control, the effectiveness and safety of pesticide use are being compromised. This highlights the urgent need for countries to strengthen their capacity on pesticide management and evidence-based decision making within the context of an integrated vector management approach.

  12. [Knowledge of vector-borne diseases (dengue, rickettsiosis and Chagas disease) in physicians].

    Science.gov (United States)

    Lugo-Caballero, César I; Dzul-Rosado, Karla; Dzul-Tut, Irving; Balam-May, Ángel; Zavala-Castro, Jorge

    2017-01-01

    The ecological conditions of Yucatan made it a suitable region for the acquisition of vector-borne diseases such as dengue, rickettsiosis, and Chagas disease. As the epidemiological burden of these diseases shows an alarming increase of severe cases, the early establishment of diagnosis and therapeutics by first-contact physicians is a critical step that is not being fulfilled due to several reasons, including poor knowledge. To determine the level of knowledge related to dengue, Chagas disease, and rickettsiosis among rural first-contact physicians of Yucatan. A survey was applied to 90 first-contact physicians from rural clinics of Yucatan, which included 32 items related to the diagnosis, treatment, and prevention of dengue, rickettsiosis, and Chagas disease. Answers were analyzed by central tendency statistics. Differences were observed among every category, however; diagnosis and therapeutics showed the lower values. Globally, 62.5% of respondents showed moderate knowledge, 37.5% poor knowledge, and 0% adequate knowledge. Results suggest that a strong campaign for a continuous diffusion of knowledge regarding these diseases is needed. In regions with high prevalence of these kinds of diseases, like Yucatan, the impact of these results on the epidemiological burden of these diseases must be evaluated.

  13. The Re-Emergence and Emergence of Vector-Borne Rickettsioses in Taiwan

    Directory of Open Access Journals (Sweden)

    Nicholas T. Minahan

    2017-12-01

    Full Text Available Rickettsial diseases, particularly vector-borne rickettsioses (VBR, have a long history in Taiwan, with studies on scrub typhus and murine typhus dating back over a century. The climatic and geographic diversity of Taiwan’s main island and its offshore islands provide many ecological niches for the diversification and maintenance of rickettsiae alike. In recent decades, scrub typhus has re-emerged as the most prevalent type of rickettsiosis in Taiwan, particularly in eastern Taiwan and its offshore islands. While murine typhus has also re-emerged on Taiwan’s western coast, it remains neglected. Perhaps more alarming than the re-emergence of these rickettsioses is the emergence of newly described VBR. The first case of human infection with Rickettsia felis was confirmed in 2005, and undetermined spotted fever group rickettsioses have recently been detected. Taiwan is at a unique advantage in terms of detecting and characterizing VBR, as it has universal health coverage and a national communicable disease surveillance system; however, these systems have not been fully utilized for this purpose. Here, we review the existing knowledge on the eco-epidemiology of VBR in Taiwan and recommend future courses of action.

  14. Zika virus infection: Past and present of another emerging vector-borne disease.

    Science.gov (United States)

    Sakkas, Hercules; Economou, Vangelis; Papadopoulou, Chrissanthy

    2016-01-01

    Zika virus infection is an emerging mosquito-borne disease, first identified in Uganda in 1947. It is caused by the Zika arbovirus, and transmitted by the bites of infected mosquitoes of the genus Aedes. For almost half a century, the Zika virus was reported as the causative agent of sporadic human infections. In 2007, the Zika virus emerged outside Asia and Africa causing an epidemic on the Island of Yap in Micronesia. The manifestation of the newly acquired human infection varies from asymptomatic to self-limiting acute febrile illness with symptoms and clinical features similar to those caused by the Dengue virus ('Dengue-like syndrome'). The real-time PCR and serological methods have been successfully applied for the diagnosis of the disease. The treatment is symptomatic, since there is no specific antiviral treatment or a vaccine. During the recent outbreaks in French Polynesia and Brazil, incidents of Guillain-Barrι syndrome and microcephaly were associated with Zika virus infection, giving rise to fears of further global spread of the virus. Prevention and vector control strategies have to be urgently implemented by national health authorities in order to contain future outbreaks in vulnerable populations. This review summarizes the existing information on Zika virus characteristics, pathogenesis and epidemiology, the available methods for the diagnosis of Zika virus infection and recent approaches for prevention and control.

  15. Gray wolf exposure to emerging vector-borne diseases in Wisconsin with comparison to domestic dogs and humans

    Science.gov (United States)

    Jara, Rocio F.; Wydeven, Adrian P.; Samuel, Michael D.

    2016-01-01

    World-wide concern over emerging vector-borne diseases has increased in recent years for both animal and human health. In the United Sates, concern about vector-borne diseases in canines has focused on Lyme disease, anaplasmosis, ehrlichiosis, and heartworm which infect domestic and wild canids. Of these diseases, Lyme and anaplasmosis are also frequently diagnosed in humans. Gray wolves (Canis lupus) recolonized Wisconsin in the 1970s, and we evaluated their temporal and geographic patterns of exposure to these four vector-borne diseases in Wisconsin as the population expanded between 1985 and 2011. A high proportion of the Wisconsin wolves were exposed to the agents that cause Lyme (65.6%) and anaplasma (47.7%), and a smaller proportion to ehrlichiosis (5.7%) and infected with heartworm (9.2%). Wolf exposure to tick borne diseases was consistently higher in older animals. Wolf exposure was markedly higher than domestic dog (Canis familiaris) exposure for all 4 disease agents during 2001–2013. We found a cluster of wolf exposure to Borrelia burgdorferi in northwestern Wisconsin, which overlaps human and domestic dog clusters for the same pathogen. In addition, wolf exposure to Lyme disease in Wisconsin has increased, corresponding with the increasing human incidence of Lyme disease in a similar time period. Despite generally high prevalence of exposure none of these diseases appear to have slowed the growth of the Wisconsin wolf population.

  16. Gray Wolf Exposure to Emerging Vector-Borne Diseases in Wisconsin with Comparison to Domestic Dogs and Humans.

    Directory of Open Access Journals (Sweden)

    Rocio F Jara

    Full Text Available World-wide concern over emerging vector-borne diseases has increased in recent years for both animal and human health. In the United Sates, concern about vector-borne diseases in canines has focused on Lyme disease, anaplasmosis, ehrlichiosis, and heartworm which infect domestic and wild canids. Of these diseases, Lyme and anaplasmosis are also frequently diagnosed in humans. Gray wolves (Canis lupus recolonized Wisconsin in the 1970s, and we evaluated their temporal and geographic patterns of exposure to these four vector-borne diseases in Wisconsin as the population expanded between 1985 and 2011. A high proportion of the Wisconsin wolves were exposed to the agents that cause Lyme (65.6% and anaplasma (47.7%, and a smaller proportion to ehrlichiosis (5.7% and infected with heartworm (9.2%. Wolf exposure to tick borne diseases was consistently higher in older animals. Wolf exposure was markedly higher than domestic dog (Canis familiaris exposure for all 4 disease agents during 2001-2013. We found a cluster of wolf exposure to Borrelia burgdorferi in northwestern Wisconsin, which overlaps human and domestic dog clusters for the same pathogen. In addition, wolf exposure to Lyme disease in Wisconsin has increased, corresponding with the increasing human incidence of Lyme disease in a similar time period. Despite generally high prevalence of exposure none of these diseases appear to have slowed the growth of the Wisconsin wolf population.

  17. Intestinal parasites and vector-borne pathogens in stray and free-roaming cats living in continental and insular Greece

    Science.gov (United States)

    Diakou, Anastasia; Di Cesare, Angela; Accettura, Paolo Matteo; Barros, Luciano; Iorio, Raffaella; Paoletti, Barbara; Frangipane di Regalbono, Antonio; Halos, Lénaïg; Beugnet, Frederic; Traversa, Donato

    2017-01-01

    This survey investigated the distribution of various intestinal parasites and vector-borne pathogens in stray and free-roaming cats living in four regions of Greece. A total number of one hundred and fifty cats living in three Islands (Crete, Mykonos and Skopelos) and in Athens municipality was established as a realistic aim to be accomplished in the study areas. All cats were examined with different microscopic, serological and molecular assays aiming at evaluating the occurrence of intestinal parasites, and exposure to or presence of vector-borne infections. A total of 135 cats (90%) was positive for one or more parasites and/or pathogens transmitted by ectoparasites. Forty-four (29.3%) cats were positive for one single infection, while 91 (60.7%) for more than one pathogen. A high number of (n. 53) multiple infections caused by feline intestinal and vector-borne agents including at least one zoonotic pathogen was detected. Among them, the most frequently recorded helminths were roundworms (Toxocara cati, 24%) and Dipylidium caninum (2%), while a high number of examined animals (58.8%) had seroreaction for Bartonella spp., followed by Rickettsia spp. (43.2%) and Leishmania infantum (6.1%). DNA-based assays revealed the zoonotic arthropod-borne organisms Bartonella henselae, Bartonella clarridgeiae, Rickettsia spp., and L. infantum. These results show that free-ranging cats living in areas of Greece under examination may be exposed to a plethora of internal parasites and vector-borne pathogens, some of them potentially able to infect humans. Therefore, epidemiological vigilance and appropriate control measures are crucial for the prevention and control of these infections and to minimize the risk of infection for people. PMID:28141857

  18. Intestinal parasites and vector-borne pathogens in stray and free-roaming cats living in continental and insular Greece.

    Directory of Open Access Journals (Sweden)

    Anastasia Diakou

    2017-01-01

    Full Text Available This survey investigated the distribution of various intestinal parasites and vector-borne pathogens in stray and free-roaming cats living in four regions of Greece. A total number of one hundred and fifty cats living in three Islands (Crete, Mykonos and Skopelos and in Athens municipality was established as a realistic aim to be accomplished in the study areas. All cats were examined with different microscopic, serological and molecular assays aiming at evaluating the occurrence of intestinal parasites, and exposure to or presence of vector-borne infections. A total of 135 cats (90% was positive for one or more parasites and/or pathogens transmitted by ectoparasites. Forty-four (29.3% cats were positive for one single infection, while 91 (60.7% for more than one pathogen. A high number of (n. 53 multiple infections caused by feline intestinal and vector-borne agents including at least one zoonotic pathogen was detected. Among them, the most frequently recorded helminths were roundworms (Toxocara cati, 24% and Dipylidium caninum (2%, while a high number of examined animals (58.8% had seroreaction for Bartonella spp., followed by Rickettsia spp. (43.2% and Leishmania infantum (6.1%. DNA-based assays revealed the zoonotic arthropod-borne organisms Bartonella henselae, Bartonella clarridgeiae, Rickettsia spp., and L. infantum. These results show that free-ranging cats living in areas of Greece under examination may be exposed to a plethora of internal parasites and vector-borne pathogens, some of them potentially able to infect humans. Therefore, epidemiological vigilance and appropriate control measures are crucial for the prevention and control of these infections and to minimize the risk of infection for people.

  19. Intestinal parasites and vector-borne pathogens in stray and free-roaming cats living in continental and insular Greece.

    Science.gov (United States)

    Diakou, Anastasia; Di Cesare, Angela; Accettura, Paolo Matteo; Barros, Luciano; Iorio, Raffaella; Paoletti, Barbara; Frangipane di Regalbono, Antonio; Halos, Lénaïg; Beugnet, Frederic; Traversa, Donato

    2017-01-01

    This survey investigated the distribution of various intestinal parasites and vector-borne pathogens in stray and free-roaming cats living in four regions of Greece. A total number of one hundred and fifty cats living in three Islands (Crete, Mykonos and Skopelos) and in Athens municipality was established as a realistic aim to be accomplished in the study areas. All cats were examined with different microscopic, serological and molecular assays aiming at evaluating the occurrence of intestinal parasites, and exposure to or presence of vector-borne infections. A total of 135 cats (90%) was positive for one or more parasites and/or pathogens transmitted by ectoparasites. Forty-four (29.3%) cats were positive for one single infection, while 91 (60.7%) for more than one pathogen. A high number of (n. 53) multiple infections caused by feline intestinal and vector-borne agents including at least one zoonotic pathogen was detected. Among them, the most frequently recorded helminths were roundworms (Toxocara cati, 24%) and Dipylidium caninum (2%), while a high number of examined animals (58.8%) had seroreaction for Bartonella spp., followed by Rickettsia spp. (43.2%) and Leishmania infantum (6.1%). DNA-based assays revealed the zoonotic arthropod-borne organisms Bartonella henselae, Bartonella clarridgeiae, Rickettsia spp., and L. infantum. These results show that free-ranging cats living in areas of Greece under examination may be exposed to a plethora of internal parasites and vector-borne pathogens, some of them potentially able to infect humans. Therefore, epidemiological vigilance and appropriate control measures are crucial for the prevention and control of these infections and to minimize the risk of infection for people.

  20. Canine vector-borne diseases in India: a review of the literature and identification of existing knowledge gaps

    Directory of Open Access Journals (Sweden)

    Coleman Glen T

    2010-04-01

    Full Text Available Abstract Despite the combination of favourable climate for parasites and vectors, and large populations of stray dogs, information concerning the epidemiology, diagnosis and management of canine vector-borne diseases in India is limited. However, with the country's expanding economy and adaptation to western culture, higher expectations and demands are being placed on veterinary surgeons for improved knowledge of diseases and control. This review aims to provide an overview of the current state of knowledge of these diseases in India and identify existing knowledge gaps in the literature which need to be addressed. The available literature on this subject, although limited, suggests that a number of canine vector-borne diseases such as filariasis, babesiosis and ehrlichiosis are endemic throughout India, as diagnosed mostly by morphological methods. Detailed investigations of the epidemiology and zoonotic potential of these pathogens has been neglected. Further study is essential to develop a better understanding of the diversity of canine vector-borne diseases in India, and their significance for veterinary and public health.

  1. Imported and travelling dogs as carriers of canine vector-borne pathogens in Germany

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    Lorentz Susanne

    2010-04-01

    Full Text Available Abstract Background With the import of pets and pets taken abroad, arthropod-borne diseases have increased in frequency in German veterinary practices. This is reflected by 4,681 dogs that have been either travelled to or relocated from endemic areas to Germany. The case history of these dogs and the laboratory findings have been compared with samples collected from 331 dogs living in an endemic area in Portugal. The various pathogens and the seroprevalences were examined to determine the occurrence of, and thus infection risk, for vector-borne pathogens in popular travel destinations. Results 4,681 dogs were examined serological for Leishmania infantum, Babesia canis and Ehrlichia canis. Buffy coats were detected for Hepatozoon canis and blood samples were examined for microfilariae via the Knott's test. The samples were sent in from animal welfare organizations or private persons via veterinary clinics. Upon individual requests, dogs were additionally examined serological for Anaplasma phagocytophilum, Borrelia burgdorferi and Rickettsia conorii. Overall B. canis was the most prevalent pathogen detected by antibody titers (23.4%, followed by L. infantum (12.2% and E. canis (10.1%. Microfilariae were detected in 7.7% and H. canis in 2.7% of the examined dogs. In 332/1862 dogs A. phagocytophilum, in 64/212 B. burgdorferi and in 20/58 R. conorii was detected. Of the 4,681 dogs, in total 4,226 were imported to Germany from endemic areas. Eighty seven dogs joined their owners for a vacation abroad. In comparison to the laboratory data from Germany, we examined 331 dogs from Portugal. The prevalence of antibodies/pathogens we detected was: 62.8% to R. conorii, 58% to B. canis, 30.5% to A. phagocytophilum, 24.8% to E. canis, 21.1% to H. canis (via PCR, 9.1% to L. infantum and 5.3% to microfilariae. Conclusions The examination of 4,681 dogs living in Germany showed pathogens like L. infantum that are non-endemic in Germany. Furthermore, the German

  2. Disease-modeling as a tool for surveillance, foresight and control of exotic vector borne diseases in the Nordic countries

    DEFF Research Database (Denmark)

    Bødker, Rene

    period e.g. a monthly temperature mean. Average monthly temperatures are likely to be suitable for predicting permanent establishment of presently exotic diseases. But mean temperatures may not predict the true potential for local spread or limited outbreaks resulting from accidental introductions...... for continuous risk assessment of the potential for local spread of exotic insect borne diseases of veterinary and human importance. In this system R0-models for various vector borne diseases are continuously updated with spatial temperature data to quantify the present risk of autochthonous cases (R0......>0) and the present risk of epidemics (R0>1) should an infected vector or host be introduced to the area. The continuously updated risk assessment maps function as an early warning system allowing authorities and industry to increase awareness and preventive measures when R0 raises above the level of ‗no possible...

  3. Vector-Borne Diseases - constant challenge for practicing veterinarians: recommendations from the CVBD World Forum

    Directory of Open Access Journals (Sweden)

    Baneth Gad

    2012-03-01

    Full Text Available Abstract The human-animal bond has been a fundamental feature of mankind's history for millennia. The first, and strongest of these, man's relationship with the dog, is believed to pre-date even agriculture, going back as far as 30,000 years. It remains at least as powerful today. Fed by the changing nature of the interactions between people and their dogs worldwide and the increasing tendency towards close domesticity, the health of dogs has never played a more important role in family life. Thanks to developments in scientific understanding and diagnostic techniques, as well as changing priorities of pet owners, veterinarians are now able, and indeed expected, to play a fundamental role in the prevention and treatment of canine disease, including canine vector-borne diseases (CVBDs. The CVBDs represent a varied and complex group of diseases, including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, ehrlichiosis, leishmaniosis, rickettsiosis and thelaziosis, with new syndromes being uncovered every year. Many of these diseases can cause serious, even life-threatening clinical conditions in dogs, with a number having zoonotic potential, affecting the human population. Today, CVBDs pose a growing global threat as they continue their spread far from their traditional geographical and temporal restraints as a result of changes in both climatic conditions and pet dog travel patterns, exposing new populations to previously unknown infectious agents and posing unprecedented challenges to veterinarians. In response to this growing threat, the CVBD World Forum, a multidisciplinary group of experts in CVBDs from around the world which meets on an annual basis, gathered in Nice (France in 2011 to share the latest research on CVBDs and discuss the best approaches to managing these diseases around the world. As a result of these discussions, we, the members of the CVBD Forum have developed the following recommendations to veterinarians

  4. Molecular detection of vector-borne pathogens in dogs and cats from Qatar.

    Science.gov (United States)

    Alho, Ana Margarida; Lima, Clara; Latrofa, Maria Stefania; Colella, Vito; Ravagnan, Silvia; Capelli, Gioia; Madeira de Carvalho, Luís; Cardoso, Luís; Otranto, Domenico

    2017-06-20

    Vector-borne diseases (VBDs) have been increasingly reported in dogs and cats worldwide. However, no data are currently available regarding canine and feline VBDs in Qatar and limited information is available from other Persian Gulf countries. Blood samples from 98 client-owned animals (i.e. 64 dogs and 34 cats) living in Doha (Qatar) were collected and the presence of genomic DNA of Anaplasma spp., Babesia spp., Dirofilaria spp., Ehrlichia spp., Hepatozoon spp., Mycoplasma spp. and Rickettsia spp. was assessed by polymerase chain reaction (PCR), real time-PCR (rt-PCR) and sequence analysis. Of the 64 dogs, 12 (18.8%) were infected with at least one pathogen (i.e. 7.8% with Mycoplasma spp., 4.7% with Babesia vogeli, 3.1% with Ehrlichia canis, and 1.6% with Anaplasma platys, Babesia gibsoni and Hepatozoon canis, each). One of the 12 dogs was co-infected with B. vogeli and E. canis. Of the 34 cats, seven (20.6%) animals were infected with at least one pathogen (i.e. 5.9% were positive for Mycoplasma spp., and 2.9% for Babesia felis, B. vogeli, E. canis, "Candidatus Mycoplasma haemominutum" and Mycoplasma haemofelis, each). No dogs or cats were positive for Dirofilaria spp. or Rickettsia spp. Although the sample sizes of dogs and cats herein analysed was moderately small, data from this study report the occurrence of A. platys, B. vogeli, B. gibsoni, E. canis, H. canis and Mycoplasma spp. in domestic dogs and of B. felis, B. vogeli, "Candidatus M. haemominutum", E. canis and M. haemofelis in domestic cats from Qatar. Further investigations along with prophylactic measures are strongly recommended in order to reduce the risk of dogs and cats acquiring VBDs in Qatar.

  5. Understanding uncertainty in temperature effects on vector-borne disease: a Bayesian approach

    Science.gov (United States)

    Johnson, Leah R.; Ben-Horin, Tal; Lafferty, Kevin D.; McNally, Amy; Mordecai, Erin A.; Paaijmans, Krijn P.; Pawar, Samraat; Ryan, Sadie J.

    2015-01-01

    Extrinsic environmental factors influence the distribution and population dynamics of many organisms, including insects that are of concern for human health and agriculture. This is particularly true for vector-borne infectious diseases like malaria, which is a major source of morbidity and mortality in humans. Understanding the mechanistic links between environment and population processes for these diseases is key to predicting the consequences of climate change on transmission and for developing effective interventions. An important measure of the intensity of disease transmission is the reproductive number R0. However, understanding the mechanisms linking R0 and temperature, an environmental factor driving disease risk, can be challenging because the data available for parameterization are often poor. To address this, we show how a Bayesian approach can help identify critical uncertainties in components of R0 and how this uncertainty is propagated into the estimate of R0. Most notably, we find that different parameters dominate the uncertainty at different temperature regimes: bite rate from 15°C to 25°C; fecundity across all temperatures, but especially ~25–32°C; mortality from 20°C to 30°C; parasite development rate at ~15–16°C and again at ~33–35°C. Focusing empirical studies on these parameters and corresponding temperature ranges would be the most efficient way to improve estimates of R0. While we focus on malaria, our methods apply to improving process-based models more generally, including epidemiological, physiological niche, and species distribution models.

  6. Response to an emerging vector-borne disease: surveillance and preparedness for Schmallenberg virus.

    Science.gov (United States)

    Roberts, H C; Elbers, A R W; Conraths, F J; Holsteg, M; Hoereth-Boentgen, D; Gethmann, J; van Schaik, G

    2014-10-15

    Surveillance for new emerging animal diseases from a European perspective is complicated by the non-harmonised approach across Member States for data capture, recording livestock populations and case definitions. In the summer of 2011, a new vector-borne Orthobunyavirus emerged in Northern Europe and for the first time, a coordinated approach to horizon scanning, risk communication, data and diagnostic test sharing allowed EU Member States to develop early predictions of the disease, its impact and risk management options. There are many different systems in place across the EU for syndromic and scanning surveillance and the differences in these systems have presented epidemiologists and risk assessors with concerns about their combined use in early identification of an emerging disease. The emergence of a new disease always will raise challenging issues around lack of capability and lack of knowledge; however, Schmallenberg virus (SBV) gave veterinary authorities an additional complex problem: the infection caused few clinical signs in adult animals, with no indication of the possible source and little evidence about its spread or means of transmission. This paper documents the different systems in place in some of the countries (Germany and the Netherlands) which detected disease initially and predicted its spread (to the UK) and how information sharing helped to inform early warning and risk assessment for Member States. Microarray technology was used to identify SBV as a new pathogen and data from the automated cattle milking systems coupled with farmer-derived data on reporting non-specific clinical signs gave the first indications of a widespread issue while the UK used meteorological modelling to map disease incursion. The coordinating role of both EFSA and the European Commission were vital as are the opportunities presented by web-based publishing for disseminating information to industry and the public. The future of detecting emerging disease looks more

  7. Climate change and vector-borne diseases: what are the implications for public health research and policy?

    OpenAIRE

    Campbell-Lendrum, Diarmid; Manga, Lucien; Bagayoko, Magaran; Sommerfeld, Johannes

    2015-01-01

    Vector-borne diseases continue to contribute significantly to the global burden of disease, and cause epidemics that disrupt health security and cause wider socioeconomic impacts around the world. All are sensitive in different ways to weather and climate conditions, so that the ongoing trends of increasing temperature and more variable weather threaten to undermine recent global progress against these diseases. Here, we review the current state of the global public health effort to address t...

  8. R0-modeling as a tool for early warning and surveillance of exotic vector borne diseases in Denmark

    DEFF Research Database (Denmark)

    Bødker, Rene; Kristensen, Birgit; Græsbøll, Kaare

    2011-01-01

    local spread of exotic insect borne diseases of veterinary and human importance. R0 models for various vector borne diseases are continuously updated with spatial temperature data to quantify the present risk of autochthonous cases (R0>0) and the present risk of epidemics (R0>1) in case an infected...... surveillance to these limited periods of potential risk, thus dramatically reducing the number of samples collected and analysed. The risk estimated from the R0 modelling may be combined with the risk of introduction from neighbouring countries and trading partners to generate a truly risk based surveillance......Modelling the potential transmission intensity of insect borne diseases with climate driven R0 process models is frequently used to assess the potential for veterinary and human infections to become established in non endemic areas. Models are often based on mean temperatures of an arbitrary time...

  9. Zoonotic and vector borne agents causing disease in adult patients hospitalized due to fever of unknown origin in Thailand

    Directory of Open Access Journals (Sweden)

    Soawapak Hinjoy

    2017-10-01

    Full Text Available Objective: To determine the etiologic agents of fever of unknown origin among populations in agricultural communities and to assess the possible risk factors for zoonotic infections. Methods: Hospitalized patients with fever of unknown origin under physician care were asked to participate and provide blood samples for laboratory tests and screening for endemic diseases at the hospitals. Samples were stored at –80 °C until they were tested at Chulalongkorn University to identify additional pathogens. Results: We were able to identify the etiologic agents in 24.6% of the 463 enrolled patients. Zoonotic and vector borne agents were confirmed in 59 cases (12.7%. Dengue virus (7.3% was the most frequently detected disease followed by scrub typhus (3.2%. There were two cases of comorbidities of scrub typhus and dengue fever. The other six cases of zoonoses were leptospirosis, melioidosis, and Streptococcus suis infections. Patients with zoonotic/vector borne agents noticed rats in their houses and reported having contact with livestock feces more frequently than those patients without zoonotic/vector borne agents. Conclusions: Dengue virus and scrub typhus were mostly detected in the rainy season. During this specific season, clinicians should raise awareness of those diseases when any patients are admitted to the hospital with fever of an unidentified source.

  10. Reflections on the Anopheles gambiae genome sequence, transgenic mosquitoes and the prospect for controlling malaria and other vector borne diseases.

    Science.gov (United States)

    Tabachnick, Walter J

    2003-09-01

    The completion of the Anopheles gambiae Giles genome sequencing project is a milestone toward developing more effective strategies in reducing the impact of malaria and other vector borne diseases. The successes in developing transgenic approaches using mosquitoes have provided another essential new tool for further progress in basic vector genetics and the goal of disease control. The use of transgenic approaches to develop refractory mosquitoes is also possible. The ability to use genome sequence to identify genes, and transgenic approaches to construct refractory mosquitoes, has provided the opportunity that with the future development of an appropriate genetic drive system, refractory transgenes can be released into vector populations leading to nontransmitting mosquitoes. An. gambiae populations incapable of transmitting malaria. This compelling strategy will be very difficult to achieve and will require a broad substantial research program for success. The fundamental information that is required on genome structure, gene function and environmental effects on genetic expression are largely unknown. The ability to predict gene effects on phenotype is rudimentary, particularly in natural populations. As a result, the release of a refractory transgene into natural mosquito populations is imprecise and there is little ability to predict unintended consequences. The new genetic tools at hand provide opportunities to address an array of important issues, many of which can have immediate impact on the effectiveness of a host of strategies to control vector borne disease. Transgenic release approaches represent only one strategy that should be pursued. A balanced research program is required.

  11. Insecticide control of vector-borne diseases: when is insecticide resistance a problem?

    Directory of Open Access Journals (Sweden)

    Ana Rivero

    Full Text Available Many of the most dangerous human diseases are transmitted by insect vectors. After decades of repeated insecticide use, all of these vector species have demonstrated the capacity to evolve resistance to insecticides. Insecticide resistance is generally considered to undermine control of vector-transmitted diseases because it increases the number of vectors that survive the insecticide treatment. Disease control failure, however, need not follow from vector control failure. Here, we review evidence that insecticide resistance may have an impact on the quality of vectors and, specifically, on three key determinants of parasite transmission: vector longevity, competence, and behaviour. We argue that, in some instances, insecticide resistance is likely to result in a decrease in vector longevity, a decrease in infectiousness, or in a change in behaviour, all of which will reduce the vectorial capacity of the insect. If this effect is sufficiently large, the impact of insecticide resistance on disease management may not be as detrimental as previously thought. In other instances, however, insecticide resistance may have the opposite effect, increasing the insect's vectorial capacity, which may lead to a dramatic increase in the transmission of the disease and even to a higher prevalence than in the absence of insecticides. Either way-and there may be no simple generality-the consequence of the evolution of insecticide resistance for disease ecology deserves additional attention.

  12. Study on coinfecting vector-borne pathogens in dogs and ticks in Rio Grande do Norte, Brazil

    Directory of Open Access Journals (Sweden)

    Luiz Ricardo Gonçalves

    Full Text Available Since dogs presenting several vector borne diseases can show none or nonspecific clinical signs depending on the phase of infection, the assessment of the particular agents involved is mandatory. The present study aimed to investigate the presence of Babesia spp., Ehrlichia spp., Anaplasma spp., Hepatozoon spp. and Leishmania spp. in blood samples and ticks, collected from two dogs from Rio Grande do Norte showing suggestive tick-borne disease by using molecular techniques. DNA of E. canis, H. canis and L. infantum were detected in blood samples and R. sanguineus ticks collected from dogs. Among all samples analyzed, two showed the presence of multiple infections with E. canis, H. canis and L. infantum chagasi. Here we highlighted the need for molecular differential diagnosis in dogs showing nonspecific clinical signs.

  13. Engaging scientists: An online survey exploring the experience of innovative biotechnological approaches to controlling vector-borne diseases.

    Science.gov (United States)

    Boëte, Christophe; Beisel, Uli; Reis Castro, Luísa; Césard, Nicolas; Reeves, R Guy

    2015-08-10

    Pioneering technologies (e.g., nanotechnology, synthetic biology or climate engineering) are often associated with potential new risks and uncertainties that can become sources of controversy. The communication of information during their development and open exchanges between stakeholders is generally considered a key issue in their acceptance. While the attitudes of the public to novel technologies have been widely considered there has been relatively little investigation of the perceptions and awareness of scientists working on human or animal diseases transmitted by arthropods. Consequently, we conducted a global survey on 1889 scientists working on aspects of vector-borne diseases, exploring, under the light of a variety of demographic and professional factors, their knowledge and awareness of an emerging biotechnology that has the potential to revolutionize the control of pest insect populations. Despite extensive media coverage of key developments (including releases of manipulated mosquitoes into human communities) this has in only one instance resulted in scientist awareness exceeding 50% on a national or regional scale. We document that awareness of pioneering releases significantly relied on private communication sources that were not equally accessible to scientists from countries with endemic vector-borne diseases (dengue and malaria). In addition, we provide quantitative analysis of the perceptions and knowledge of specific biotechnological approaches to controlling vector-borne disease, which are likely to impact the way in which scientists around the world engage in the debate about their value. Our results indicate that there is scope to strengthen already effective methods of communication, in addition to a strong demand by scientists (expressed by 79.9% of respondents) to develop new, creative modes of public engagement.

  14. Vector-borne pathogens in dogs and red foxes from the federal state of Brandenburg, Germany.

    Science.gov (United States)

    Liesner, Jana M; Krücken, Jürgen; Schaper, Roland; Pachnicke, Stefan; Kohn, Barbara; Müller, Elisabeth; Schulze, Christoph; von Samson-Himmelstjerna, Georg

    2016-07-15

    Dirofilaria repens is endemic in eastern and southern European regions but was recently found in Germany in dogs, mosquitoes and one human patient. Since some of the positive dog and mosquito samples were collected in Brandenburg, it was aimed to systematically assess the prevalence of D. repens and other canine vector-borne pathogens in Brandenburg. Dog owners also received a questionnaire and were asked to provide more information about the dogs including travel history. In total, 1023 dog blood samples as well as 195 fox spleen and 179 fox blood samples were collected. DNA was analysed by PCR for the presence of filariae, piroplasms, anaplasmataceae and Rickettsia spp. Filariae were detected in six dogs (0.6%), two were positive for DNA from D. repens, two from Dirofilaria immitis and two from Acanthocheilonema reconditum. One of the D. repens positive dogs originated from an animal shelter in Brandenburg, but the origin of the other one remained unknown. Interestingly, both D. repens ITS-1 sequences showed 100% identity to a D. repens sample obtained from a Japanese woman that travelled in Europe and were 97% identical to a newly proposed species Dirofilaria sp. 'hongkongensis' described from Hong Kong. However, identity to other D. repens sequences from Thailand was considerably lower (81%). Identity of 12S rRNA and cytochrome oxidase I to D. repens samples from southern Europe was 99%. Due to the low number of Dirofilaria spp. positive dogs and since the origin of these was unknown, endemic occurrence of Dirofilaria in Brandenburg could not be confirmed. Anaplasma phagocytophilum was found in 15 dogs (1.5%), Candidatus Neoehrlichia mikurensis in three dogs (0.3%) and E. canis in one dog (0.1%), which was co-infected with D. repens. Rickettsia spp. were detected in 8 dogs (0.8%), seven were Rickettsia raoultii and one was Rickettsia felis. To the author's knowledge, R. raoultii DNA was detected for the first time in dogs in Germany in this study and Candidatus

  15. Priorities and needs for research on urban interventions targeting vector-borne diseases: rapid review of scoping and systematic reviews.

    Science.gov (United States)

    Bermudez-Tamayo, Clara; Mukamana, Olive; Carabali, Mabel; Osorio, Lyda; Fournet, Florence; Dabiré, Kounbobr Roch; Turchi Marteli, Celina; Contreras, Adolfo; Ridde, Valéry

    2016-12-01

    This paper highlights the critical importance of evidence on vector-borne diseases (VBD) prevention and control interventions in urban settings when assessing current and future needs, with a view to setting policy priorities that promote inclusive and equitable urban health services. Research should produce knowledge about policies and interventions that are intended to control and prevent VBDs at the population level and to reduce inequities. Such interventions include policy, program, and resource distribution approaches that address the social determinants of health and exert influence at organizational and system levels.

  16. Criteria for the prioritization of public health interventions for climate-sensitive vector-borne diseases in Quebec.

    Directory of Open Access Journals (Sweden)

    Valerie Hongoh

    Full Text Available Prioritizing resources for optimal responses to an ever growing list of existing and emerging infectious diseases represents an important challenge to public health. In the context of climate change, there is increasing anticipated variability in the occurrence of infectious diseases, notably climate-sensitive vector-borne diseases. An essential step in prioritizing efforts is to identify what considerations and concerns to take into account to guide decisions and thus set disease priorities. This study was designed to perform a comprehensive review of criteria for vector-borne disease prioritization, assess their applicability in a context of climate change with a diverse cross-section of stakeholders in order to produce a baseline list of considerations to use in this decision-making context. Differences in stakeholder choices were examined with regards to prioritization of these criteria for research, surveillance and disease prevention and control objectives. A preliminary list of criteria was identified following a review of the literature. Discussions with stakeholders were held to consolidate and validate this list of criteria and examine their effects on disease prioritization. After this validation phase, a total of 21 criteria were retained. A pilot vector-borne disease prioritization exercise was conducted using PROMETHEE to examine the effects of the retained criteria on prioritization in different intervention domains. Overall, concerns expressed by stakeholders for prioritization were well aligned with categories of criteria identified in previous prioritization studies. Weighting by category was consistent between stakeholders overall, though some significant differences were found between public health and non-public health stakeholders. From this exercise, a general model for climate-sensitive vector-borne disease prioritization has been developed that can be used as a starting point for further public health prioritization

  17. Criteria for the prioritization of public health interventions for climate-sensitive vector-borne diseases in Quebec.

    Science.gov (United States)

    Hongoh, Valerie; Gosselin, Pierre; Michel, Pascal; Ravel, André; Waaub, Jean-Philippe; Campagna, Céline; Samoura, Karim

    2017-01-01

    Prioritizing resources for optimal responses to an ever growing list of existing and emerging infectious diseases represents an important challenge to public health. In the context of climate change, there is increasing anticipated variability in the occurrence of infectious diseases, notably climate-sensitive vector-borne diseases. An essential step in prioritizing efforts is to identify what considerations and concerns to take into account to guide decisions and thus set disease priorities. This study was designed to perform a comprehensive review of criteria for vector-borne disease prioritization, assess their applicability in a context of climate change with a diverse cross-section of stakeholders in order to produce a baseline list of considerations to use in this decision-making context. Differences in stakeholder choices were examined with regards to prioritization of these criteria for research, surveillance and disease prevention and control objectives. A preliminary list of criteria was identified following a review of the literature. Discussions with stakeholders were held to consolidate and validate this list of criteria and examine their effects on disease prioritization. After this validation phase, a total of 21 criteria were retained. A pilot vector-borne disease prioritization exercise was conducted using PROMETHEE to examine the effects of the retained criteria on prioritization in different intervention domains. Overall, concerns expressed by stakeholders for prioritization were well aligned with categories of criteria identified in previous prioritization studies. Weighting by category was consistent between stakeholders overall, though some significant differences were found between public health and non-public health stakeholders. From this exercise, a general model for climate-sensitive vector-borne disease prioritization has been developed that can be used as a starting point for further public health prioritization exercises relating to

  18. Advanced megaesophagus (Group III secondary to vector-borne Chagas disease in a 20-month-old infant

    Directory of Open Access Journals (Sweden)

    Anis Rassi

    2012-04-01

    Full Text Available The authors report the case of a female infant with Group III (or Grade III megaesophagus secondary to vector-borne Chagas disease, resulting in severe malnutrition that reversed after surgery (Heller technique. The infant was then treated with the antiparasitic drug benznidazole, and the infection was cured, as demonstrated serologically and parasitologically. After follow-up of several years without evidence of disease, with satisfactory weight and height development, the patient had her first child at age 23, in whom serological tests for Chagas disease yielded negative results. Thirty years after the initial examination, the patient's electrocardiogram, echocardiogram, and chest radiography remained normal.

  19. Climate Change and Spatiotemporal Distributions of Vector-Borne Diseases in Nepal--A Systematic Synthesis of Literature.

    Directory of Open Access Journals (Sweden)

    Meghnath Dhimal

    Full Text Available Despite its largely mountainous terrain for which this Himalayan country is a popular tourist destination, Nepal is now endemic for five major vector-borne diseases (VBDs, namely malaria, lymphatic filariasis, Japanese encephalitis, visceral leishmaniasis and dengue fever. There is increasing evidence about the impacts of climate change on VBDs especially in tropical highlands and temperate regions. Our aim is to explore whether the observed spatiotemporal distributions of VBDs in Nepal can be related to climate change.A systematic literature search was performed and summarized information on climate change and the spatiotemporal distribution of VBDs in Nepal from the published literature until December 2014 following providing items for systematic review and meta-analysis (PRISMA guidelines.We found 12 studies that analysed the trend of climatic data and are relevant for the study of VBDs, 38 studies that dealt with the spatial and temporal distribution of disease vectors and disease transmission. Among 38 studies, only eight studies assessed the association of VBDs with climatic variables. Our review highlights a pronounced warming in the mountains and an expansion of autochthonous cases of VBDs to non-endemic areas including mountain regions (i.e., at least 2,000 m above sea level. Furthermore, significant relationships between climatic variables and VBDs and their vectors are found in short-term studies.Taking into account the weak health care systems and difficult geographic terrain of Nepal, increasing trade and movements of people, a lack of vector control interventions, observed relationships between climatic variables and VBDs and their vectors and the establishment of relevant disease vectors already at least 2,000 m above sea level, we conclude that climate change can intensify the risk of VBD epidemics in the mountain regions of Nepal if other non-climatic drivers of VBDs remain constant.

  20. Genetic shifting: a novel approach for controlling vector-borne diseases

    OpenAIRE

    Powell, Jeffrey R.; Tabachnick, Walter J.

    2014-01-01

    Rendering populations of vectors of diseases incapable of transmitting pathogens through genetic methods has long been a goal of vector geneticists. We outline a method to achieve this goal that does not involve introduction of any new genetic variants to the target population. Rather we propose that shifting the frequencies of naturally occurring alleles that confer refractoriness to transmission can reduce transmission below a sustainable level. The program employs methods successfully used...

  1. Pre-travel advice concerning vector-borne diseases received by travelers prior to visiting Cuzco, Peru.

    Science.gov (United States)

    Mejia, Christian R; Centeno, Emperatriz; Cruz, Briggitte; Cvetkovic-Vega, Aleksandar; Delgado, Edison; Rodriguez-Morales, Alfonso J

    2016-01-01

    Peru is an increasingly popular tourist destination that poses a risk to travelers due to endemic vector-borne diseases (VBDs). The objective of our study was to determine which factors are associated with receiving pre-travel advice (PTA) for VBDs among travelers visiting Cuzco, Peru. A cross-sectional secondary analysis based on data from a survey among travelers departing Cuzco at Alejandro Velazco Astete International Airport during the period January-March 2012 was conducted. From the 1819 travelers included in the original study, 1717 were included in secondary data analysis. Of these participants, 42.2% received PTA and 2.9% were informed about vector-borne diseases, including yellow fever (1.8%), malaria (1.6%) and dengue fever (0.1%). Receiving information on VBDs was associated with visiting areas endemic to yellow fever and dengue fever in Peru. The only disease travelers received specific recommendations for before visiting an endemic area for was yellow fever. Only 1 in 30 tourists received information on VBD prevention; few of those who traveled to an endemic area were warned about specific risks for infectious diseases prior to their trip. These important findings show that most tourists who travel to Peru do not receive PTA for the prevention of infectious and VBD, which can affect not only the travelers but their countries of origin as well. Copyright © 2015 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

  2. The structuring process of the macroparasite community of an experimental population of cichlasoma urophthalmus through time

    Science.gov (United States)

    Vidal-Martinez; Kennedy; Aguirre-Macedo

    1998-09-01

    The structuring process of the macroparasite community of caged Cichlasoma urophthalmus was studied over time using sentinel fish. Three thousand uninfected cichlids were stocked in floating cages introduced into a quarry in which a wild population of the same species was present. Caged and wild cichlids were sampled monthly over 6 and 7 months, respectively. Seventeen macroparasite species were found in the wild C. urophthalmus population, ten of which were detected in the caged population after 6 months. Early infections were by those species that were more frequent and abundant in the wild population, while helminths with a low prevalence and abundance in the wild appeared later in the caged fish population. The results suggested that the structuring process of the macroparasite community of caged C. urophthalmus followed a predictable pattern, in which those species that were most frequent and abundant in the wild were the first to establish in sentinel fish.

  3. Assessing the impact of climate change on vector-borne viruses in the EU through the elicitation of expert opinion.

    Science.gov (United States)

    Gale, P; Brouwer, A; Ramnial, V; Kelly, L; Kosmider, R; Fooks, A R; Snary, E L

    2010-02-01

    Expert opinion was elicited to undertake a qualitative risk assessment to estimate the current and future risks to the European Union (EU) from five vector-borne viruses listed by the World Organization for Animal Health. It was predicted that climate change will increase the risk of incursions of African horse sickness virus (AHSV), Crimean-Congo haemorrhagic fever virus (CCHFV) and Rift Valley fever virus (RVFV) into the EU from other parts of the world, with African swine fever virus (ASFV) and West Nile virus (WNV) being less affected. Currently the predicted risks of incursion were lowest for RVFV and highest for ASFV. Risks of incursion were considered for six routes of entry (namely vectors, livestock, meat products, wildlife, pets and people). Climate change was predicted to increase the risk of incursion from entry of vectors for all five viruses to some degree, the strongest effects being predicted for AHSV, CCHFV and WNV. This work will facilitate identification of appropriate risk management options in relation to adaptations to climate change.

  4. Inter-model comparison of the landscape determinants of vector-borne disease: implications for epidemiological and entomological risk modeling.

    Science.gov (United States)

    Lorenz, Alyson; Dhingra, Radhika; Chang, Howard H; Bisanzio, Donal; Liu, Yang; Remais, Justin V

    2014-01-01

    Extrapolating landscape regression models for use in assessing vector-borne disease risk and other applications requires thoughtful evaluation of fundamental model choice issues. To examine implications of such choices, an analysis was conducted to explore the extent to which disparate landscape models agree in their epidemiological and entomological risk predictions when extrapolated to new regions. Agreement between six literature-drawn landscape models was examined by comparing predicted county-level distributions of either Lyme disease or Ixodes scapularis vector using Spearman ranked correlation. AUC analyses and multinomial logistic regression were used to assess the ability of these extrapolated landscape models to predict observed national data. Three models based on measures of vegetation, habitat patch characteristics, and herbaceous landcover emerged as effective predictors of observed disease and vector distribution. An ensemble model containing these three models improved precision and predictive ability over individual models. A priori assessment of qualitative model characteristics effectively identified models that subsequently emerged as better predictors in quantitative analysis. Both a methodology for quantitative model comparison and a checklist for qualitative assessment of candidate models for extrapolation are provided; both tools aim to improve collaboration between those producing models and those interested in applying them to new areas and research questions.

  5. Inter-model comparison of the landscape determinants of vector-borne disease: implications for epidemiological and entomological risk modeling.

    Directory of Open Access Journals (Sweden)

    Alyson Lorenz

    Full Text Available Extrapolating landscape regression models for use in assessing vector-borne disease risk and other applications requires thoughtful evaluation of fundamental model choice issues. To examine implications of such choices, an analysis was conducted to explore the extent to which disparate landscape models agree in their epidemiological and entomological risk predictions when extrapolated to new regions. Agreement between six literature-drawn landscape models was examined by comparing predicted county-level distributions of either Lyme disease or Ixodes scapularis vector using Spearman ranked correlation. AUC analyses and multinomial logistic regression were used to assess the ability of these extrapolated landscape models to predict observed national data. Three models based on measures of vegetation, habitat patch characteristics, and herbaceous landcover emerged as effective predictors of observed disease and vector distribution. An ensemble model containing these three models improved precision and predictive ability over individual models. A priori assessment of qualitative model characteristics effectively identified models that subsequently emerged as better predictors in quantitative analysis. Both a methodology for quantitative model comparison and a checklist for qualitative assessment of candidate models for extrapolation are provided; both tools aim to improve collaboration between those producing models and those interested in applying them to new areas and research questions.

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

    Science.gov (United States)

    Padilla, Julio César; Lizarazo, Fredy Eberto; Murillo, Olga Lucía; Mendigaña, Fernando Antonio; Pachón, Edwin; Vera, Mauricio Javier

    2017-03-29

    Introducción. Las enfermedades transmitidas por vectores representan más de 17 % de todas las enfermedades infecciosas y causan anualmente un millón de defunciones a nivel mundial. En Colombia, la malaria, el dengue, la enfermedad de Chagas y las leishmaniasis son condiciones endemoepidémicas persistentes.Objetivo. Determinar el comportamiento epidemiológico de las enfermedades transmitidas por vectores en zonas urbanas y rurales de Colombia entre 1990 y 2016.Materiales y métodos. Se hizo un estudio descriptivo del comportamiento epidemiológico de las principales enfermedades transmitidas por vectores en zonas urbanas y rurales de Colombia entre 1990 y 2016, con la información proveniente de fuentes oficiales secundarias.Resultados. En el periodo estudiado se registraron 5'360.134 casos de enfermedades transmitidas por vectores, de los cuales 54,7 % fueron de malaria y 24,9 % de dengue. Estos casos concentraron el 80 % de la carga acumulada de casos de enfermedades transmitidas por vectores. Las medianas de las tasas de incidencia fueron 1.371 y 188 por 100.00 habitantes para malaria y dengue, respectivamente. Además, los casos de chikungunya fueron 774.831 desde su introducción en el 2014 y, los de Zika, 117.674 desde su aparición en 2015. En las zonas rurales predominaron las enfermedades parasitarias transmitidas por vectores como la malaria, las leishmaniasis y la enfermedad de Chagas. A nivel urbano, predominaron el dengue, el chikungunya y el Zika.Conclusiones. La transmisión en Colombia de estas enfermedades es persistente en las zonas urbanas y en las rurales, y de tipo endemoepidémico en los casos de malaria, dengue, leishmaniasis y enfermedad de Chagas. Dicha transmisión se ha dado de manera focalizada y con patrones variables de intensidad. Asimismo, se mantienen las condiciones que han favorecido la transmisión emergente de nuevas arbovirosis.

  7. Characterization and Detection of Vector-borne Diseases in Endemic Transmission Areas

    Science.gov (United States)

    2016-01-18

    Achee NL, Gould F, Perkins TA, Reiner RC, Jr., Morrison AC, et al . 2015. A critical assessment of vector control for dengue prevention. PLoS Negl Trop...Beier JC, Perkins PV, Onyango F, et al . 1988 . Identification of malaria species by ELISA in sporozoite and oocyst infected Anopheles from western...for the detection of low-level parasitemias of a single malaria parasite species, Demas et al . demonstrated that alternative gene targets may be more

  8. Mosquito Vector Diversity across Habitats in Central Thailand Endemic for Dengue and Other Arthropod-Borne Diseases

    Science.gov (United States)

    Thongsripong, Panpim; Green, Amy; Kittayapong, Pattamaporn; Kapan, Durrell; Wilcox, Bruce; Bennett, Shannon

    2013-01-01

    Recent years have seen the greatest ecological disturbances of our times, with global human expansion, species and habitat loss, climate change, and the emergence of new and previously-known infectious diseases. Biodiversity loss affects infectious disease risk by disrupting normal relationships between hosts and pathogens. Mosquito-borne pathogens respond to changing dynamics on multiple transmission levels and appear to increase in disturbed systems, yet current knowledge of mosquito diversity and the relative abundance of vectors as a function of habitat change is limited. We characterize mosquito communities across habitats with differing levels of anthropogenic ecological disturbance in central Thailand. During the 2008 rainy season, adult mosquito collections from 24 sites, representing 6 habitat types ranging from forest to urban, yielded 62,126 intact female mosquitoes (83,325 total mosquitoes) that were assigned to 109 taxa. Female mosquito abundance was highest in rice fields and lowest in forests. Diversity indices and rarefied species richness estimates indicate the mosquito fauna was more diverse in rural and less diverse in rice field habitats, while extrapolated estimates of true richness (Chao1 and ACE) indicated higher diversity in the forest and fragmented forest habitats and lower diversity in the urban. Culex sp. (Vishnui subgroup) was the most common taxon found overall and the most frequent in fragmented forest, rice field, rural, and suburban habitats. The distributions of species of medical importance differed significantly across habitat types and were always lowest in the intact, forest habitat. The relative abundance of key vector species, Aedes aegypti and Culex quinquefasciatus, was negatively correlated with diversity, suggesting that direct species interactions and/or habitat-mediated factors differentially affecting invasive disease vectors may be important mechanisms linking biodiversity loss to human health. Our results are an

  9. Implementing Cargo Movement into Climate Based Risk Assessment of Vector-Borne Diseases

    Directory of Open Access Journals (Sweden)

    Stephanie Margarete Thomas

    2014-03-01

    Full Text Available During the last decades the disease vector Aedes albopictus (Asian tiger mosquito has rapidly spread around the globe. Global shipment of goods contributes to its permanent introduction. Invaded regions are facing novel and serious public health concerns, especially regarding the transmission of formerly non-endemic arboviruses such as dengue and chikungunya. The further development and potential spread to other regions depends largely on their climatic suitability. Here, we have developed a tool for identifying and prioritizing European areas at risk for the establishment of Aedes albopictus by taking into account, for the first time, the freight imports from this mosquito’s endemic countries and the climate suitability at harbors and their surrounding regions. In a second step we consider the further transport of containers by train and inland waterways because these types of transport can be well controlled. We identify European regions at risk, where a huge amount of transported goods meet climatically suitable conditions for the disease vector. The current and future suitability of the climate for Aedes albopictus was modeled by a correlative niche model approach and the Regional Climate Model COSMO-CLM. This risk assessment combines impacts of globalization and global warming to improve effective and proactive interventions in disease vector surveillance and control actions.

  10. Emerging vector-borne diseases in dromedaries in Tunisia: West Nile, bluetongue, epizootic haemorrhagic disease and Rift Valley fever.

    Science.gov (United States)

    Hassine, Thameur B; Amdouni, Jihane; Monaco, Federica; Savini, Giovanni; Sghaier, Soufien; Selimen, Imed B; Chandoul, Walid; Hamida, Khaled B; Hammami, Salah

    2017-03-31

    A total of 118 sera were collected during 2016 from two groups of dromedaries from Kebili and Medenine governorates in the south of Tunisia. The aim of this study was to provide the first serological investigation of four emerging vector-borne diseases in two groups of dromedaries in Tunisia. Sera were tested by ELISA and serum neutralisation test to identify West Nile virus (WNV), bluetongue virus (BTV), epizootic haemorrhagic disease virus (EHDV) and Rift Valley fever virus (RVFV). In the first group, the seroprevalence for BTV was 4.6%, while in the second group, it was 25.8% for WNV and 9.7% for BTV. Only serotype 1 was detected for BTV in the two groups. No evidence for circulation of RVF and EHD viruses was revealed. Results indicated that dromedaries can be infected with BTV and WNV, suggesting that this species might play a significant role in the epizootiology of these viral diseases in Tunisia and neighbouring countries.

  11. Cross-sectional survey of health management and prevalence of vector-borne diseases, endoparasites and ectoparasites in Samoan dogs.

    Science.gov (United States)

    Carslake, R J; Hill, K E; Sjölander, K; Hii, S F; Prattley, D; Acke, E

    2017-12-01

    To determine the prevalence of selected canine vector-borne diseases (Leishmania infantum, Anaplasma spp., Ehrlichia canis, Borrelia burgdorferi and Dirofilaria immitis) and endo- and ectoparasites in Samoan dogs presenting for surgical sterilisation and to report on the general health management of the dogs. This study was a prospective serological cross-sectional survey. Management data were obtained for 242 dogs by interview with their owners. Blood samples were collected from 237 dogs and screened for the canine vector-borne diseases using point-of-care qualitative ELISA assays. Anaplasma spp. positive samples were screened by PCR and sequenced for species identification. Rectal faecal samples were collected from 204 dogs for faecal flotation and immunofluorescent antibody tests were performed for Giardia and Cryptosporidium spp. on a subset of 93 faecal samples. The skin and coat of 221 dogs were examined for presence of ectoparasites. The D. immitis antigen was detected in 46.8% (111/237) of dogs. Seroprevalence of Anaplasma spp. was 8.4% (20/237); A. platys was confirmed by PCR. Prevalence of hookworm was 92.6% (185/205) and Giardia was 29.0% (27/93). Ectoparasites were detected on 210/221 (95.0%) of dogs examined and 228/242 dogs (94.2%) had previously never received any preventative medication. There was a very high prevalence of D. immitis, hookworm and external parasites in Samoan dogs, and prophylactic medication is rarely administered. This is the first report confirming A. platys in Samoa and the South Pacific islands. The public health implications of poor management of the dogs should be considered and investigated further. © 2017 Australian Veterinary Association.

  12. Bacterial and protozoal agents of feline vector-borne diseases in domestic and stray cats from southern Portugal

    Science.gov (United States)

    2014-01-01

    Background Feline vector-borne diseases (FVBD) have emerged in recent years, showing a wider geographic distribution and increased global prevalence. In addition to their veterinary importance, domestic cats play a central role in the transmission cycles of some FVBD agents by acting as reservoirs and sentinels, a circumstance that requires a One Health approach. The aim of the present work was to molecularly detect feline vector-borne bacteria and protozoa with veterinary and zoonotic importance, and to assess associated risk factors in cats from southern Portugal. Methods Six hundred and forty-nine cats (320 domestic and 329 stray), from veterinary medical centres and animal shelters in southern Portugal, were studied. Anaplasma spp./Ehrlichia spp., Babesia spp., Bartonella spp., Borrelia burgdorferi sensu lato, Hepatozoon spp. and Leishmania spp. infections were evaluated by polymerase chain reaction (PCR) in blood samples. Results One hundred and ninety-four (29.9%) cats were PCR-positive to at least one of the tested genera or complex of FVBD agents. Sixty-four (9.9%) cats were positive to Leishmania spp., 56 (8.6%) to Hepatozoon spp., 43 (6.6%) to Babesia spp., 35 (5.4%) to Anaplasma spp./Ehrlichia spp., 19 (2.9%) to Bartonella spp. and 14 (2.2%) to B. burgdorferi s.l. Thirty-three (5.1%) cats were positive to two (n = 29) or three (n = 4) genera/complex. Babesia vogeli, Bartonella clarridgeiae, Bartonella henselae, Ehrlichia canis, Hepatozoon felis and Leishmania infantum were identified by DNA sequencing. Conclusions The occurrence of FVBD agents in southern Portugal, some of them with zoonotic character, emphasizes the need to alert the veterinary community, owners and public health authorities for the risk of infection. Control measures should be implemented to prevent the infection of cats, other vertebrate hosts and people. PMID:24655431

  13. Interactions between macroparasites and microparasites drive infection patterns in free-ranging African buffalo

    NARCIS (Netherlands)

    Jolles, Anna E.; Ezenwa, Vanessa O.; Etienne, Rampal S.; Turner, Wendy C.; Olff, Han; Antolin, M.F.

    Epidemiological studies typically focus on single-parasite systems, although most hosts harbor multiple parasite species; thus, the potential impacts of co-infection on disease dynamics are only beginning to be recognized. Interactions between macroparasites, such as gastrointestinal nematodes, and

  14. Interactions between macroparasites and microparasites drive infection patterns in free-ranging African buffalo

    NARCIS (Netherlands)

    Jolles, A.E.; Ezenwa, V.O.; Etienne, R.S.

    2008-01-01

    Epidemiological studies typically focus on single-parasite systems, although most hosts harbor multiple parasite species; thus, the potential impacts of co-infection on disease dynamics are only beginning to be recognized. Interactions between macroparasites, such as gastrointestinal nematodes, and

  15. International Network for Capacity Building for the Control of Emerging Viral Vector-Borne Zoonotic Diseases: Arbo-Zoonet

    NARCIS (Netherlands)

    Ahmed, J.; Bouloy, M.; Ergonul, O.; Fooks, A.R.; Paweska, J.; Chevalier, V.; Drosten, C.; Moormann, R.J.M.; Tordo, N.; Vatansever, Z.; Calistri, P.; Estrada-Pena, A.; Mirazimi, A.; Unger, H.; Yin, H.; Seitzer, U.

    2009-01-01

    Arboviruses are arthropod-borne viruses, which include West Nile fever virus (WNFV), a mosquito-borne virus, Rift Valley fever virus (RVFV), a mosquito-borne virus, and Crimean-Congo haemorrhagic fever virus (CCHFV), a tick-borne virus. These arthropod-borne viruses can cause disease in different

  16. 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.

  17. Impacts of Climate Change on Vector Borne Diseases in the Mediterranean Basin - Implications for Preparedness and Adaptation Policy.

    Science.gov (United States)

    Negev, Maya; Paz, Shlomit; Clermont, Alexandra; Pri-Or, Noemie Groag; Shalom, Uri; Yeger, Tamar; Green, Manfred S

    2015-06-15

    The Mediterranean region is vulnerable to climatic changes. A warming trend exists in the basin with changes in rainfall patterns. It is expected that vector-borne diseases (VBD) in the region will be influenced by climate change since weather conditions influence their emergence. For some diseases (i.e., West Nile virus) the linkage between emergence andclimate change was recently proved; for others (such as dengue) the risk for local transmission is real. Consequently, adaptation and preparation for changing patterns of VBD distribution is crucial in the Mediterranean basin. We analyzed six representative Mediterranean countries and found that they have started to prepare for this threat, but the preparation levels among them differ, and policy mechanisms are limited and basic. Furthermore, cross-border cooperation is not stable and depends on international frameworks. The Mediterranean countries should improve their adaptation plans, and develop more cross-sectoral, multidisciplinary and participatory approaches. In addition, based on experience from existing local networks in advancing national legislation and trans-border cooperation, we outline recommendations for a regional cooperation framework. We suggest that a stable and neutral framework is required, and that it should address the characteristics and needs of African, Asian and European countries around the Mediterranean in order to ensure participation. Such a regional framework is essential to reduce the risk of VBD transmission, since the vectors of infectious diseases know no political borders.

  18. RNA Interference: A Promising Tool in the Control of Important Vector Born Diseases Zika, Dengue Fever, and Malaria

    Directory of Open Access Journals (Sweden)

    Jalil Nejati

    2017-05-01

    Full Text Available Background and Objectives: RNA interference is a process, in which a molecule of double-stranded RNA prevents the expression of a particular gene and leads to its silencing. Application of this technology in the control of disease-carrying insects is rising in agriculture and medical sciences. Also, its application in control of insect-borne diseases could be considered as a new, important, and effective approach. In this article, it was attempted to study the mechanisms of RNA interference, routs of its delivery to insects, as well as its application in genetic control of disease vector insects. Methods: In this study, 71 indexed articles in databases, such as Pubmed, SID, Scopus, Science direct, and Google scholar, were used. Results: dsRNA could be delivered to insect body through three routes of oral, injection, and Impregnation. The mechanism of dsRNA entrance into the cells has considerable effect on the success and applicability of this technique. Identification of host-parasite relationship in the insect body is one of the important applications of RNAi in medical entomology. Conclusion: Although, there is a considerable number of researches on RNAi in the agricultural pests field, studies on insect vectors of human diseases have been mostly in-vivo. However, application of RNAi is suggested as a new, safe and applicable approach, alone or along with other methods. Certainly, further researches in this field can pave the way for enforcement measures in the control of disease vectors, especially Zika, dengue fever, and malaria in the not so distant future.

  19. Integrated mapping of establishment risk for emerging vector-borne infections: a case study of canine leishmaniasis in southwest France.

    Directory of Open Access Journals (Sweden)

    Nienke Hartemink

    Full Text Available BACKGROUND: Zoonotic visceral leishmaniasis is endemic in the Mediterranean Basin, where the dog is the main reservoir host. The disease's causative agent, Leishmania infantum, is transmitted by blood-feeding female sandflies. This paper reports an integrative study of canine leishmaniasis in a region of France spanning the southwest Massif Central and the northeast Pyrenees, where the vectors are the sandflies Phlebotomus ariasi and P. perniciosus. METHODS: Sandflies were sampled in 2005 using sticky traps placed uniformly over an area of approximately 100 by 150 km. High- and low-resolution satellite data for the area were combined to construct a model of the sandfly data, which was then used to predict sandfly abundance throughout the area on a pixel by pixel basis (resolution of c. 1 km. Using literature- and expert-derived estimates of other variables and parameters, a spatially explicit R(0 map for leishmaniasis was constructed within a Geographical Information System. R(0 is a measure of the risk of establishment of a disease in an area, and it also correlates with the amount of control needed to stop transmission. CONCLUSIONS: To our knowledge, this is the first analysis that combines a vector abundance prediction model, based on remotely-sensed variables measured at different levels of spatial resolution, with a fully mechanistic process-based temperature-dependent R(0 model. The resulting maps should be considered as proofs-of-principle rather than as ready-to-use risk maps, since validation is currently not possible. The described approach, based on integrating several modeling methods, provides a useful new set of tools for the study of the risk of outbreaks of vector-borne diseases.

  20. Benefit of insecticide-treated nets, curtains and screening on vector borne diseases, excluding malaria: a systematic review and meta-analysis

    NARCIS (Netherlands)

    Wilson, A.L.; Dhiman, R.C.; Kitron, U.; Scott, T.W.; Berg, van den H.; Lindsay, S.W.

    2014-01-01

    Introduction Insecticide-treated nets (ITNs) are one of the main interventions used for malaria control. However, these nets may also be effective against other vector borne diseases (VBDs). We conducted a systematic review and meta-analysis to estimate the efficacy of ITNs, insecticide-treated

  1. Emerging vector-borne zoonoses: eco-epidemiology and public health implications in India.

    Science.gov (United States)

    Dhiman, Ramesh C

    2014-01-01

    The diseases originating from animals or associated with man and animals are remerging and have resulted in considerable morbidity and mortality. The present review highlights the re-emergence of emerging mainly zoonotic diseases like chikungunya, scrub typhus, and extension of spatial distribution of cutaneous leishmaniasis from western Rajasthan to Himachal Pradesh, Kerala, and Haryana states; West Nile virus to Assam, and non-endemic areas of Japanese encephalitis (JE) like Maharashtra and JE to Delhi; Crimean-Congo hemorrhagic fever making inroads in Ahmedabad; and reporting fifth parasite of human malaria with possibility of zoonosis have been highlighted, which necessitates further studies for prevention and control. Emphasis has been given on understanding the ecology of reservoir hosts of pathogen, micro niche of vector species, climatic, socioeconomic risk factors, etc. Development of facilities for diagnosis of virus from insects, reservoirs, and human beings (like BSL4, which has been established in NIV, Pune), awareness about symptoms of new emerging viral and other zoonotic diseases, differential diagnosis, risk factors (climatic, ecological, and socioeconomic) and mapping of disease-specific vulnerable areas, and mathematical modeling for projecting epidemiological scenario is needed for preparedness of public health institutes. It is high time to understand the ecological link of zoonotic or anthroponotic diseases for updated risk maps and epidemiological knowledge for effective preventive and control measures. The public health stakeholders in India as well as in Southeast Asia should emphasize on understanding the eco-epidemiology of the discussed zoonotic diseases for taking preventive actions.

  2. Emerging Vector borne zoonoses: eco-­epidemiology and public health implications in India

    Directory of Open Access Journals (Sweden)

    Ramesh C Dhiman

    2014-09-01

    Full Text Available The diseases originating from animals or associated with man and animals are remerging and have resulted in considerable morbidity and mortality. The present review highlights the re-emergence of emerging mainly zoonotic diseases like chikungunya, scrub typhus, extension of spatial distribution of cutaneous leishmaniasis from Western Rajasthan to Himachal Pradesh, Kerala, and Haryana states; West Nile virus to Assam, and non- endemic areas of JE like Maharashtra and JE to Delhi; Crimean Congo Hemorrhagic Fever making inroads in Ahmedabad; reporting fifth parasite of human malaria with possibility of zoonosis have been highlighted which necessitates further studies for prevention and control. Emphasis has been given on understanding the ecology of reservoir hosts of pathogen, micro niche of vector species, climatic, socioeconomic risk factors etc. Development of facilities for diagnosis of virus from insects, reservoirs and human beings (like BSL4 which has been established in NIV, Pune, awareness about symptoms of new emerging viral and other zoonotic diseases, differential diagnosis, risk factors (Climatic, ecological and socioeconomic and mapping of disease specific vulnerable areas, mathematical modeling for projecting epidemiological scenario, are needed for preparedness of public health institutes. It is high time to understand the ecological link of zoonotic or anthroponotic diseases for updated risk maps and epidemiological knowledge for effective preventive and control measures. The public health stakeholders in India as well as in south East Asia should emphasize on understanding the eco-epidemiology of the discussed zoonotic diseases for taking preventive actions.

  3. Temporal and spatial scaling of the genetic structure of a vector-borne plant pathogen.

    Science.gov (United States)

    Coletta-Filho, Helvécio D; Francisco, Carolina S; Almeida, Rodrigo P P

    2014-02-01

    The ecology of plant pathogens of perennial crops is affected by the long-lived nature of their immobile hosts. In addition, changes to the genetic structure of pathogen populations may affect disease epidemiology and management practices; examples include local adaptation of more fit genotypes or introduction of novel genotypes from geographically distant areas via human movement of infected plant material or insect vectors. We studied the genetic structure of Xylella fastidiosa populations causing disease in sweet orange plants in Brazil at multiple scales using fast-evolving molecular markers (simple-sequence DNA repeats). Results show that populations of X. fastidiosa were regionally isolated, and that isolation was maintained for populations analyzed a decade apart from each other. However, despite such geographic isolation, local populations present in year 2000 were largely replaced by novel genotypes in 2009 but not as a result of migration. At a smaller spatial scale (individual trees), results suggest that isolates within plants originated from a shared common ancestor. In summary, new insights on the ecology of this economically important plant pathogen were obtained by sampling populations at different spatial scales and two different time points.

  4. Prevalence of Selected Zoonotic and Vector-Borne Agents in Dogs and Cats on the Pine Ridge Reservation

    Directory of Open Access Journals (Sweden)

    A. Valeria Scorza

    2017-09-01

    Full Text Available The prevalence of intestinal parasites and vector-borne agents of dogs and cats in the Pine Ridge Reservation, South Dakota were determined. Fecal samples (84 dogs, 9 cats were examined by centrifugal floatation and by immunofluorescence assay (FA for Giardia and Cryptosporidium. PCR was performed on Giardia [beta-giardin (bg, triose phosphate isomerase (tpi, glutamate dehydrogenase genes (gdh] and Cryptosporidium [heat shock protein-70 gene (hsp] FA positive samples. Cat sera (n = 32 were tested for antibodies against Bartonella spp., Toxoplasma gondii, and FIV, and antigens of FeLV and Dirofilaria immitis. Dog sera (n = 82 were tested for antibodies against T. gondii, Borrelia burgdorferi, Ehrlichia canis, and Anaplasma phagocytophilum and D. immitis antigen. Blood samples (92 dogs, 39 cats were assessed by PCR for amplification of DNA of Bartonella spp., Ehrlichia spp., Anaplasma spp., haemoplasmas, and Babesia spp. (dogs only. The most significant results were Giardia spp. (32% by FA, Taenia spp. (17.8% and Cryptosporidium spp. (7.1%. The Giardia isolates typed as the dog-specific assemblages C or D and four Cryptosporidium isolates typed as C. canis. Antibodies against T. gondii were detected in 15% of the dogs. Antibodies against Bartonella spp. and against T. gondii were detected in 37.5% and 6% of the cats respectively. FeLV antigen was detected in 10% of the cats.

  5. Climate and Population Health Vulnerabilities to Vector-Borne Diseases: Increasing Resilience Under Climate Change Conditions in Africa

    Science.gov (United States)

    Ceccato, P.; McDonald, K. C.; Podest, E.; De La Torre Juarez, M.; Kruczkiewicz, A.; Lessel, J.; Jensen, K.; Thomson, M. C.

    2014-12-01

    The International Research Institute for Climate and Society (IRI), the City University of New York (CUNY) and NASA Jet Propulsion Laboratory (JPL) in collaboration with NASA SERVIR are developing tools to monitor climate variables (precipitation, temperature, vegetation, water bodies, inundation) that help projects in Africa to increase resilience to climate change for vector-borne diseases (i.e. malaria, trypanosomiasis, leishmaniasis, and schistosomiasis). Through the development of new products to monitor precipitation, water bodies and inundation, IRI, CUNY and JPL provide tools and capacity building to research communities, ministries of health and World Health Organization in Africa to: 1) Develop research teams' ability to appropriately use climate data as part of their research 2) Enable research teams and ministries to integrate climate information into social and economic drivers of vulnerability and opportunities for adaptation to climate change 3) Inform better policies and programs for climate change adaptation. This oral presentation will demonstrate how IRI, CUNY, and JPL developed new products, tools and capacity building to achieve the three objectives mentioned above.

  6. Emerging vector-borne diseases in dromedaries in Tunisia: West Nile, bluetongue, epizootic haemorrhagic disease and Rift Valley fever

    Directory of Open Access Journals (Sweden)

    Thameur B. Hassine

    2017-03-01

    Full Text Available A total of 118 sera were collected during 2016 from two groups of dromedaries from Kebili and Medenine governorates in the south of Tunisia. The aim of this study was to provide the first serological investigation of four emerging vector-borne diseases in two groups of dromedaries in Tunisia. Sera were tested by ELISA and serum neutralisation test to identify West Nile virus (WNV, bluetongue virus (BTV, epizootic haemorrhagic disease virus (EHDV and Rift Valley fever virus (RVFV. In the first group, the seroprevalence for BTV was 4.6%, while in the second group, it was 25.8% for WNV and 9.7% for BTV. Only serotype 1 was detected for BTV in the two groups. No evidence for circulation of RVF and EHD viruses was revealed. Results indicated that dromedaries can be infected with BTV and WNV, suggesting that this species might play a significant role in the epizootiology of these viral diseases in Tunisia and neighbouring countries.

  7. Climate and Health Vulnerability to Vector-Borne Diseases: Increasing Resilience under Climate Change Conditions in Africa

    Science.gov (United States)

    Ceccato, P.

    2015-12-01

    The International Research Institute for Climate and Society (IRI), the City University of New York (CUNY) and NASA Jet Propulsion Laboratory (JPL) in collaboration with NASA SERVIR are developing tools to monitor climate variables (precipitation, temperature, vegetation, water bodies, inundation) that help projects in Africa to increase resilience to climate change for vector-borne diseases ( malaria, trypanosomiasis, leishmaniasis, and schistosomiasis). Through the development of new products to monitor precipitation, water bodies and inundation, IRI, CUNY and JPL provide tools and capacity building to research communities; ministries of health; the WMO Global Framework for Climate and Services; and World Health Organization in Africa to: 1) Develop research teams' ability to appropriately use climate data as part of their research 2) Enable research teams and ministries to integrate climate information into social and economic drivers of vulnerability and opportunities for adaptation to climate change 3) Inform better policies and programs for climate change adaptation. This oral presentation will demonstrate how IRI, CUNY, and JPL developed new products, tools and capacity building to achieve the three objectives mentioned above with examples in South Africa, Zimbabwe, Tanzania and Malawi.

  8. 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

  9. Genetic diversity and potential vectors and reservoirs of Cucurbit aphid-borne yellows virus in southeastern Spain.

    Science.gov (United States)

    Kassem, Mona A; Juarez, Miguel; Gómez, Pedro; Mengual, Carmen M; Sempere, Raquel N; Plaza, María; Elena, Santiago F; Moreno, Aranzazu; Fereres, Alberto; Aranda, Miguel A

    2013-11-01

    The genetic variability of a Cucurbit aphid-borne yellows virus (CABYV) (genus Polerovirus, family Luteoviridae) population was evaluated by determining the nucleotide sequences of two genomic regions of CABYV isolates collected in open-field melon and squash crops during three consecutive years in Murcia (southeastern Spain). A phylogenetic analysis showed the existence of two major clades. The sequences did not cluster according to host, year, or locality of collection, and nucleotide similarities among isolates were 97 to 100 and 94 to 97% within and between clades, respectively. The ratio of nonsynonymous to synonymous nucleotide substitutions reflected that all open reading frames have been under purifying selection. Estimates of the population's genetic diversity were of the same magnitude as those previously reported for other plant virus populations sampled at larger spatial and temporal scales, suggesting either the presence of CABYV in the surveyed area long before it was first described, multiple introductions, or a particularly rapid diversification. We also determined the full-length sequences of three isolates, identifying the occurrence and location of recombination events along the CABYV genome. Furthermore, our field surveys indicated that Aphis gossypii was the major vector species of CABYV and the most abundant aphid species colonizing melon fields in the Murcia (Spain) region. Our surveys also suggested the importance of the weed species Ecballium elaterium as an alternative host and potential virus reservoir.

  10. How will climate change pathways and mitigation options alter incidence of vector-borne diseases? A framework for leishmaniasis in South and Meso-America.

    Directory of Open Access Journals (Sweden)

    Bethan V Purse

    Full Text Available The enormous global burden of vector-borne diseases disproportionately affects poor people in tropical, developing countries. Changes in vector-borne disease impacts are often linked to human modification of ecosystems as well as climate change. For tropical ecosystems, the health impacts of future environmental and developmental policy depend on how vector-borne disease risks trade off against other ecosystem services across heterogeneous landscapes. By linking future socio-economic and climate change pathways to dynamic land use models, this study is amongst the first to analyse and project impacts of both land use and climate change on continental-scale patterns in vector-borne diseases. Models were developed for cutaneous and visceral leishmaniasis in the Americas-ecologically complex sand fly borne infections linked to tropical forests and diverse wild and domestic mammal hosts. Both diseases were hypothesised to increase with available interface habitat between forest and agricultural or domestic habitats and with mammal biodiversity. However, landscape edge metrics were not important as predictors of leishmaniasis. Models including mammal richness were similar in accuracy and predicted disease extent to models containing only climate and land use predictors. Overall, climatic factors explained 80% and land use factors only 20% of the variance in past disease patterns. Both diseases, but especially cutaneous leishmaniasis, were associated with low seasonality in temperature and precipitation. Since such seasonality increases under future climate change, particularly under strong climate forcing, both diseases were predicted to contract in geographical extent to 2050, with cutaneous leishmaniasis contracting by between 35% and 50%. Whilst visceral leishmaniasis contracted slightly more under strong than weak management for carbon, biodiversity and ecosystem services, future cutaneous leishmaniasis extent was relatively insensitive to future

  11. Vectors

    DEFF Research Database (Denmark)

    Boeriis, Morten; van Leeuwen, Theo

    2017-01-01

    should be taken into account in discussing ‘reactions’, which Kress and van Leeuwen link only to eyeline vectors. Finally, the question can be raised as to whether actions are always realized by vectors. Drawing on a re-reading of Rudolf Arnheim’s account of vectors, these issues are outlined......This article revisits the concept of vectors, which, in Kress and van Leeuwen’s Reading Images (2006), plays a crucial role in distinguishing between ‘narrative’, action-oriented processes and ‘conceptual’, state-oriented processes. The use of this concept in image analysis has usually focused...

  12. Zoonotic and Vector-Borne Infections Among Urban Homeless and Marginalized People in the United States and Europe, 1990-2014.

    Science.gov (United States)

    Leibler, Jessica H; Zakhour, Christine M; Gadhoke, Preety; Gaeta, Jessie M

    2016-07-01

    In high-income countries, homeless individuals in urban areas often live in crowded conditions with limited sanitation and personal hygiene. The environment of homelessness in high-income countries may result in intensified exposure to ectoparasites and urban wildlife, which can transmit infections. To date, there have been no systematic evaluations of the published literature to assess vector-borne and zoonotic disease risk to these populations. The primary objectives of this study were to identify diversity, prevalence, and risk factors for vector-borne and zoonotic infections among people experiencing homelessness and extreme poverty in urban areas of high-income countries. We conducted a systematic review and narrative synthesis of published epidemiologic studies of zoonotic and vector-borne infections among urban homeless and very poor people in the United States and Europe from 1990 to 2014. Thirty-one observational studies and 14 case studies were identified (n = 45). Seroprevalence to the human louse-borne pathogen Bartonella quintana (seroprevalence range: 0-37.5%) was identified most frequently, with clinical disease specifically observed among HIV-positive individuals. Seropositivity to Bartonella henselae (range: 0-10.3%) and Rickettsia akari (range: 0-16.2%) was noted in multiple studies. Serological evidence of exposure to Rickettsia typhi, Rickettsia prowazekii, Bartonella elizabethae, West Nile virus, Borellia recurrentis, lymphocytic choriomeningitis virus, Wohlfartiimonas chitiniclastica, Seoul hantavirus (SEOV), and Leptospira species was also identified in published studies, with SEOV associated with chronic renal disease later in life. HIV infection, injection drug use, and heavy drinking were noted across multiple studies as risk factors for infection with vector-borne and zoonotic pathogens. B. quintana was the most frequently reported vector-borne infection identified in our article. Delousing efforts and active surveillance among HIV

  13. MosquitoMap and the Mal-area calculator: new web tools to relate mosquito species distribution with vector borne disease.

    Science.gov (United States)

    Foley, Desmond H; Wilkerson, Richard C; Birney, Ian; Harrison, Stanley; Christensen, Jamie; Rueda, Leopoldo M

    2010-02-18

    Mosquitoes are important vectors of diseases but, in spite of various mosquito faunistic surveys globally, there is a need for a spatial online database of mosquito collection data and distribution summaries. Such a resource could provide entomologists with the results of previous mosquito surveys, and vector disease control workers, preventative medicine practitioners, and health planners with information relating mosquito distribution to vector-borne disease risk. A web application called MosquitoMap was constructed comprising mosquito collection point data stored in an ArcGIS 9.3 Server/SQL geodatabase that includes administrative area and vector species x country lookup tables. In addition to the layer containing mosquito collection points, other map layers were made available including environmental, and vector and pathogen/disease distribution layers. An application within MosquitoMap called the Mal-area calculator (MAC) was constructed to quantify the area of overlap, for any area of interest, of vector, human, and disease distribution models. Data standards for mosquito records were developed for MosquitoMap. MosquitoMap is a public domain web resource that maps and compares georeferenced mosquito collection points to other spatial information, in a geographical information system setting. The MAC quantifies the Mal-area, i.e. the area where it is theoretically possible for vector-borne disease transmission to occur, thus providing a useful decision tool where other disease information is limited. The Mal-area approach emphasizes the independent but cumulative contribution to disease risk of the vector species predicted present. MosquitoMap adds value to, and makes accessible, the results of past collecting efforts, as well as providing a template for other arthropod spatial databases.

  14. Climate change and vector-borne diseases: what are the implications for public health research and policy?

    Science.gov (United States)

    Campbell-Lendrum, Diarmid; Manga, Lucien; Bagayoko, Magaran; Sommerfeld, Johannes

    2015-01-01

    Vector-borne diseases continue to contribute significantly to the global burden of disease, and cause epidemics that disrupt health security and cause wider socioeconomic impacts around the world. All are sensitive in different ways to weather and climate conditions, so that the ongoing trends of increasing temperature and more variable weather threaten to undermine recent global progress against these diseases. Here, we review the current state of the global public health effort to address this challenge, and outline related initiatives by the World Health Organization (WHO) and its partners. Much of the debate to date has centred on attribution of past changes in disease rates to climate change, and the use of scenario-based models to project future changes in risk for specific diseases. While these can give useful indications, the unavoidable uncertainty in such analyses, and contingency on other socioeconomic and public health determinants in the past or future, limit their utility as decision-support tools. For operational health agencies, the most pressing need is the strengthening of current disease control efforts to bring down current disease rates and manage short-term climate risks, which will, in turn, increase resilience to long-term climate change. The WHO and partner agencies are working through a range of programmes to (i) ensure political support and financial investment in preventive and curative interventions to bring down current disease burdens; (ii) promote a comprehensive approach to climate risk management; (iii) support applied research, through definition of global and regional research agendas, and targeted research initiatives on priority diseases and population groups. PMID:25688013

  15. Climate change and vector-borne diseases: what are the implications for public health research and policy?

    Science.gov (United States)

    Campbell-Lendrum, Diarmid; Manga, Lucien; Bagayoko, Magaran; Sommerfeld, Johannes

    2015-04-05

    Vector-borne diseases continue to contribute significantly to the global burden of disease, and cause epidemics that disrupt health security and cause wider socioeconomic impacts around the world. All are sensitive in different ways to weather and climate conditions, so that the ongoing trends of increasing temperature and more variable weather threaten to undermine recent global progress against these diseases. Here, we review the current state of the global public health effort to address this challenge, and outline related initiatives by the World Health Organization (WHO) and its partners. Much of the debate to date has centred on attribution of past changes in disease rates to climate change, and the use of scenario-based models to project future changes in risk for specific diseases. While these can give useful indications, the unavoidable uncertainty in such analyses, and contingency on other socioeconomic and public health determinants in the past or future, limit their utility as decision-support tools. For operational health agencies, the most pressing need is the strengthening of current disease control efforts to bring down current disease rates and manage short-term climate risks, which will, in turn, increase resilience to long-term climate change. The WHO and partner agencies are working through a range of programmes to (i) ensure political support and financial investment in preventive and curative interventions to bring down current disease burdens; (ii) promote a comprehensive approach to climate risk management; (iii) support applied research, through definition of global and regional research agendas, and targeted research initiatives on priority diseases and population groups. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  16. Malaria and Other Vector-Borne Infection Surveillance in the U.S. Department of Defense Armed Forces Health Surveillance Center-Global Program: Review of 2009 Accomplishments

    Science.gov (United States)

    2011-03-04

    Vector borne infections (VBIs) such as malaria, dengue fever, yellow fever, scrub typhus , and plague comprise a significant proportion of the global...a VBI: scrub typhus (19), murine typhus (three), Japanese encephalitis (JE) (two), primary dengue infection (12), secondary dengue infection (nine...prioritized by GSRI, half are VBIs (malaria, dengue fever, Rift Valley fever, Chikungunya, CCHF, sandfly fever, O’nyong-nyong, Sindbis virus, scrub typhus

  17. Status of pesticide management in the practice of vector control: a global survey in countries at risk of malaria or other major vector-borne diseases

    NARCIS (Netherlands)

    Berg, van den H.; Hii, J.; Soares, A.; Mnzava, A.; Ameneshewa, B.; Dash, A.P.; Ejov, M.; Tan, S.H.; Matthews, G.; Yadav, R.S.; Zaim, M.

    2011-01-01

    Background: It is critical that vector control pesticides are used for their acceptable purpose without causing adverse effects on health and the environment. This paper provides a global overview of the current status of pesticides management in the practice of vector control. Methods: A

  18. Molecular detection of vector-borne pathogens in blood and splenic samples from dogs with splenic disease.

    Science.gov (United States)

    Movilla, Rebeca; Altet, Laura; Serrano, Lorena; Tabar, María-Dolores; Roura, Xavier

    2017-03-13

    The spleen is a highly perfused organ involved in the immunological control and elimination of vector-borne pathogens (VBP), which could have a fundamental role in the pathogenesis of splenic disease. This study aimed to evaluate certain VBP in samples from dogs with splenic lesions. Seventy-seven EDTA-blood and 64 splenic tissue samples were collected from 78 dogs with splenic disease in a Mediterranean area. Babesia spp., Bartonella spp., Ehrlichia/Anaplasma spp., Hepatozoon canis, Leishmania infantum, hemotropic Mycoplasma spp. and Rickettsia spp. were targeted using PCR assays. Sixty EDTA-blood samples from dogs without evidence of splenic lesions were included as a control group. More than half (51.56%) of the biopsies (33/64) were consistent with benign lesions and 48.43% (31/64) with malignancy, mostly hemangiosarcoma (25/31). PCR yielded positive results in 13 dogs with spleen alterations (16.67%), for Babesia canis (n = 3), Babesia gibsoni (n = 2), hemotropic Mycoplasma spp. (n = 2), Rickettsia massiliae (n = 1) and "Babesia vulpes" (n = 1), in blood; and for B. canis, B. gibsoni, Ehrlichia canis and L. infantum (n = 1 each), in spleen. Two control dogs (3.3%) were positive for B. gibsoni and H. canis (n = 1 each). Benign lesions were detected in the 61.54% of infected dogs (8/13); the remaining 38.46% were diagnosed with malignancies (5/13). Infection was significantly associated to the presence of splenic disease (P = 0.013). There was no difference in the prevalence of infection between dogs with benign and malignant splenic lesions (P = 0.69); however B. canis was more prevalent in dogs with hemangiosarcoma (P = 0.006). VBP infection could be involved in the pathogenesis of splenic disease. The immunological role of the spleen could predispose to alterations of this organ in infected dogs. Interestingly, all dogs with B. canis infection were diagnosed with hemangiosarcoma in the present survey. As previously

  19. Vector-borne diseases of small companion animals in Namibia: Literature review, knowledge gaps and opportunity for a One Health approach

    Directory of Open Access Journals (Sweden)

    Bruce H. Noden

    2015-11-01

    Full Text Available Namibia has a rich history in veterinary health but little is known about the vector-borne diseases that affect companion dogs and cats. The aim of this review is to summarise the existing published and available unpublished literature, put it into a wider geographical context, and explore some significant knowledge gaps. To date, only two filarial pathogens (Dirofilaria repens and Acanthocheilonema dracunculoides and three tick-borne pathogens (Babesia canis vogeli, Hepatozoon canis and Ehrlichia canis have been reported. Most studies have focused solely on dogs and cats in the urban Windhoek and surrounding areas, with almost nothing reported in rural farming areas, in either the populous northern regions or the low-income urban areas where animal owners have limited access to veterinary services. With the development of several biomedical training programmes in the country, there is now an excellent opportunity to address zoonotic vector-borne diseases through a One Health approach so as to assess the risks to small companion animals as well as diseases of public health importance.

  20. Multi-agent systems in epidemiology: a first step for computational biology in the study of vector-borne disease transmission

    Directory of Open Access Journals (Sweden)

    Guégan Jean-François

    2008-10-01

    Full Text Available Abstract Background Computational biology is often associated with genetic or genomic studies only. However, thanks to the increase of computational resources, computational models are appreciated as useful tools in many other scientific fields. Such modeling systems are particularly relevant for the study of complex systems, like the epidemiology of emerging infectious diseases. So far, mathematical models remain the main tool for the epidemiological and ecological analysis of infectious diseases, with SIR models could be seen as an implicit standard in epidemiology. Unfortunately, these models are based on differential equations and, therefore, can become very rapidly unmanageable due to the too many parameters which need to be taken into consideration. For instance, in the case of zoonotic and vector-borne diseases in wildlife many different potential host species could be involved in the life-cycle of disease transmission, and SIR models might not be the most suitable tool to truly capture the overall disease circulation within that environment. This limitation underlines the necessity to develop a standard spatial model that can cope with the transmission of disease in realistic ecosystems. Results Computational biology may prove to be flexible enough to take into account the natural complexity observed in both natural and man-made ecosystems. In this paper, we propose a new computational model to study the transmission of infectious diseases in a spatially explicit context. We developed a multi-agent system model for vector-borne disease transmission in a realistic spatial environment. Conclusion Here we describe in detail the general behavior of this model that we hope will become a standard reference for the study of vector-borne disease transmission in wildlife. To conclude, we show how this simple model could be easily adapted and modified to be used as a common framework for further research developments in this field.

  1. Knowledge, Attitude and Practices of Vector-Borne Disease Prevention during the Emergence of a New Arbovirus: Implications for the Control of Chikungunya Virus in French Guiana.

    Directory of Open Access Journals (Sweden)

    Camille Fritzell

    2016-11-01

    Full Text Available During the last decade, French Guiana has been affected by major dengue fever outbreaks. Although this arbovirus has been a focus of many awareness campaigns, very little information is available about beliefs, attitudes and behaviors regarding vector-borne diseases among the population of French Guiana. During the first outbreak of the chikungunya virus, a quantitative survey was conducted among high school students to study experiences, practices and perceptions related to mosquito-borne diseases and to identify socio-demographic, cognitive and environmental factors that could be associated with the engagement in protective behaviors.A cross-sectional survey was administered in May 2014, with a total of 1462 students interviewed. Classrooms were randomly selected using a two-stage selection procedure with cluster samples. A multiple correspondence analysis (MCA associated with a hierarchical cluster analysis and with an ordinal logistic regression was performed. Chikungunya was less understood and perceived as a more dreadful disease than dengue fever. The analysis identified three groups of individual protection levels against mosquito-borne diseases: "low" (30%, "moderate" (42% and "high" (28%". Protective health behaviors were found to be performed more frequently among students who were female, had a parent with a higher educational status, lived in an individual house, and had a better understanding of the disease.This study allowed us to estimate the level of protective practices against vector-borne diseases among students after the emergence of a new arbovirus. These results revealed that the adoption of protective behaviors is a multi-factorial process that depends on both sociocultural and cognitive factors. These findings may help public health authorities to strengthen communication and outreach strategies, thereby increasing the adoption of protective health behaviors, particularly in high-risk populations.

  2. Clinical and molecular investigation of a canine distemper outbreak and vector-borne infections in a group of rescue dogs imported from Hungary to Switzerland.

    Science.gov (United States)

    Willi, Barbara; Spiri, Andrea M; Meli, Marina L; Grimm, Felix; Beatrice, Laura; Riond, Barbara; Bley, Tim; Jordi, Rolf; Dennler, Matthias; Hofmann-Lehmann, Regina

    2015-07-16

    Canine distemper virus (CDV) is a major pathogen of dogs and wild carnivores worldwide. In Switzerland, distemper in domestic dogs is rarely reported. In recent years, the import of dogs from Eastern Europe to Switzerland has steadily increased. In the present study, we describe a distemper outbreak in 15 rescue dogs that were imported from Hungary to Switzerland by an animal welfare organisation. The data on vaccination and medical history were recorded (14 dogs), and the samples were collected to investigate CDV and vector-borne infections (13 dogs) and canine parvovirus infection (12 dogs). The dogs were monitored for six months. One dog was euthanised directly after import. Thirteen dogs showed clinical signs after arrival, i.e., diarrhoea (57 %), coughing (43 %) and nasal and/or ocular discharge (21 %); radiographic findings that were compatible with bronchopneumonia were present in four dogs. CDV infection was diagnosed in 11 dogs (85 %); 10 dogs (91 %) tested PCR-positive in conjunctival swabs. Vector-borne infections (Babesia spp., Leishmania infantum, Dirofilaria immitis) were found in 4 dogs (31 %). Three dogs were hospitalized, and six dogs received ambulatory therapy for up to two months until recovery. None of the dogs developed neurological disease. CDV shedding was detected for a period of up to four months. Because dogs were put under strict quarantine until CDV shedding ceased, CDV did not spread to any other dogs. The CDV isolates showed 99 % sequence identity in the HA gene among each other and belonged to the Arctic-like lineage of CDV. The present study highlights the imminent risks of spreading contagious viral and vector-borne infections through the non-selective import of sick dogs and dogs with incomplete vaccination from Eastern Europe. CDV shedding was detected for several months after the cessation of clinical signs, which emphasised the roles of asymptomatic carriers in CDV epidemiology. A long-term follow-up using sensitive PCR and

  3. Climate variability and change in the United States: potential impacts on vector- and rodent-borne diseases.

    OpenAIRE

    Gubler, D J; Reiter, P; Ebi, K L; Yap, W; Nasci, R; Patz, J A

    2001-01-01

    Diseases such as plague, typhus, malaria, yellow fever, and dengue fever, transmitted between humans by blood-feeding arthropods, were once common in the United States. Many of these diseases are no longer present, mainly because of changes in land use, agricultural methods, residential patterns, human behavior, and vector control. However, diseases that may be transmitted to humans from wild birds or mammals (zoonoses) continue to circulate in nature in many parts of the country. Most vector...

  4. Investigating the use of support vector machine classification on structural brain images of preterm-born teenagers as a biological marker.

    Directory of Open Access Journals (Sweden)

    Carlton Chu

    Full Text Available Preterm birth has been shown to induce an altered developmental trajectory of brain structure and function. With the aid support vector machine (SVM classification methods we aimed to investigate whether MRI data, collected in adolescence, could be used to predict whether an individual had been born preterm or at term. To this end we collected T1-weighted anatomical MRI data from 143 individuals (69 controls, mean age 14.6y. The inclusion criteria for those born preterm were birth weight ≤ 1500g and gestational age < 37w. A linear SVM was trained on the grey matter segment of MR images in two different ways. First, all the individuals were used for training and classification was performed by the leave-one-out method, yielding 93% correct classification (sensitivity = 0.905, specificity = 0.942. Separately, a random half of the available data were used for training twice and each time the other, unseen, half of the data was classified, resulting 86% and 91% accurate classifications. Both gestational age (R = -0.24, p<0.04 and birth weight (R = -0.51, p < 0.001 correlated with the distance to decision boundary within the group of individuals born preterm. Statistically significant correlations were also found between IQ (R = -0.30, p < 0.001 and the distance to decision boundary. Those born small for gestational age did not form a separate subgroup in these analyses. The high rate of correct classification by the SVM motivates further investigation. The long-term goal is to automatically and non-invasively predict the outcome of preterm-born individuals on an individual basis using as early a scan as possible.

  5. Evaluation of a continuous indicator for syndromic surveillance through simulation. application to vector borne disease emergence detection in cattle using milk yield.

    Directory of Open Access Journals (Sweden)

    Aurélien Madouasse

    Full Text Available Two vector borne diseases, caused by the Bluetongue and Schmallenberg viruses respectively, have emerged in the European ruminant populations since 2006. Several diseases are transmitted by the same vectors and could emerge in the future. Syndromic surveillance, which consists in the routine monitoring of indicators for the detection of adverse health events, may allow an early detection. Milk yield is routinely measured in a large proportion of dairy herds and could be incorporated as an indicator in a surveillance system. However, few studies have evaluated continuous indicators for syndromic surveillance. The aim of this study was to develop a framework for the quantification of both disease characteristics and model predictive abilities that are important for a continuous indicator to be sensitive, timely and specific for the detection of a vector-borne disease emergence. Emergences with a range of spread characteristics and effects on milk production were simulated. Milk yields collected monthly in 48 713 French dairy herds were used to simulate 576 disease emergence scenarios. First, the effect of disease characteristics on the sensitivity and timeliness of detection were assessed: Spatio-temporal clusters of low milk production were detected with a scan statistic using the difference between observed and simulated milk yields as input. In a second step, the system specificity was evaluated by running the scan statistic on the difference between observed and predicted milk yields, in the absence of simulated emergence. The timeliness of detection depended mostly on how easily the disease spread between and within herds. The time and location of the emergence or adding random noise to the simulated effects had a limited impact on the timeliness of detection. The main limitation of the system was the low specificity i.e. the high number of clusters detected from the difference between observed and predicted productions, in the absence of

  6. A reduce and replace strategy for suppressing vector-borne diseases: insights from a stochastic, spatial model.

    Directory of Open Access Journals (Sweden)

    Kenichi W Okamoto

    Full Text Available Two basic strategies have been proposed for using transgenic Aedes aegypti mosquitoes to decrease dengue virus transmission: population reduction and population replacement. Here we model releases of a strain of Ae. aegypti carrying both a gene causing conditional adult female mortality and a gene blocking virus transmission into a wild population to assess whether such releases could reduce the number of competent vectors. We find this "reduce and replace" strategy can decrease the frequency of competent vectors below 50% two years after releases end. Therefore, this combined approach appears preferable to releasing a strain carrying only a female-killing gene, which is likely to merely result in temporary population suppression. However, the fixation of anti-pathogen genes in the population is unlikely. Genetic drift at small population sizes and the spatially heterogeneous nature of the population recovery after releases end prevent complete replacement of the competent vector population. Furthermore, releasing more individuals can be counter-productive in the face of immigration by wild-type mosquitoes, as greater population reduction amplifies the impact wild-type migrants have on the long-term frequency of the anti-pathogen gene. We expect the results presented here to give pause to expectations for driving an anti-pathogen construct to fixation by relying on releasing individuals carrying this two-gene construct. Nevertheless, in some dengue-endemic environments, a spatially heterogeneous decrease in competent vectors may still facilitate decreasing disease incidence.

  7. Torradoviruses are transmitted in a semi-persistent and stylet-borne manner by three whitefly vectors

    NARCIS (Netherlands)

    Verbeek, M.; Bekkum, van P.J.; Dullemans, A.M.; Vlugt, van der R.A.A.

    2014-01-01

    Members of the genus Torradovirus (family Secoviridae, type species Tomato torrado virus, ToTV) are spherical plant viruses transmitted by the whitefly species Trialeurodes vaporariorum and Bemisia tabaci. Knowledge on the mode of vector transmission is lacking for torradoviruses. Here, the mode of

  8. The emergence and maintenance of vector-borne diseases in the Khyber Pakhtunkhwa Province (KPK and the Federally Administered Tribal Areas (FATA of Pakistan

    Directory of Open Access Journals (Sweden)

    Nathan Christopher Nieto

    2012-07-01

    Full Text Available Human populations throughout much of the world are experiencing unprecedented changes in their relationship to the environment and their interactions with the animals with which so many humans are intimately dependent upon. These changes result not only from human induced changes in the climate, but also from population demographic changes due to wars, social unrest, behavioral changes resulting from cultural mixing, and large changes in land-use practices. Each of these social shifts can affect the maintenance and emergence of arthropod vectors disease or the pathogenic organisms themselves. A good example is the country of Pakistan, with a large rural population and developing urban economy, it also maintains a wide diversity of entomological disease vectors, including biting flies, mosquitoes, and ticks. Pathogens endemic to the region include the agents of piroplasmosis, rickettsiosis, spirocheteosis, and viral hemorrhagic fevers and encephalitis. The northwestern region of the country, including the Khyber Pakhtunkhwa Province (KPK, formerly the North-West Frontier Provence (NWFP, and the Federally Administered Tribal Areas (FATA are mountainous regions with a high degree of habitat diversity that has recently undergone a massive increase in human population density due to an immigrating refugee population from neighboring war-torn Afghanistan. Vector-borne diseases in people and livestock are common in KPK and FATA regions due to the limited use of vector control measures and access to livestock vaccines. The vast majority of people in this region live in abject poverty with >70% of the population living directly from production gained in animal husbandry. In many instances whole families live directly alongside their animal counterparts. In addition, there is little to no awareness of the threat posed by ticks and transmission of either zoonotic or veterinary pathogens. Recent emergence of Crimean-Congo hemorrhagic fever virus in rural

  9. Elucidating transmission dynamics and host-parasite-vector relationships for rodent-borne Bartonella spp. in Madagascar

    Directory of Open Access Journals (Sweden)

    Cara E. Brook

    2017-09-01

    Full Text Available Bartonella spp. are erythrocytic bacteria transmitted via arthropod vectors, which infect a broad range of vertebrate hosts, including humans. We investigated transmission dynamics and host-parasite-vector relationships for potentially zoonotic Bartonella spp. in invasive Rattus rattus hosts and associated arthropod ectoparasites in Madagascar. We identified five distinct species of Bartonella (B. elizabethae 1, B. elizabethae 2, B. phoceensis 1, B. rattimassiliensis 1, and B. tribocorum 1 infecting R. rattus rodents and their ectoparasites. We fit standard epidemiological models to species-specific age-prevalence data for the four Bartonella spp. with sufficient data, thus quantifying age-structured force of infection. Known zoonotic agents, B. elizabethae 1 and 2, were best described by models exhibiting high forces of infection in early age class individuals and allowing for recovery from infection, while B. phoceensis 1 and B. rattimassiliensis 1 were best fit by models of lifelong infection without recovery and substantially lower forces of infection. Nested sequences of B. elizabethae 1 and 2 were recovered from rodent hosts and their Synopsyllus fonquerniei and Xenopsylla cheopsis fleas, with a particularly high prevalence in the outdoor-dwelling, highland-endemic S. fonquerniei. These findings expand on force of infection analyses to elucidate the ecological niche of the zoonotic Bartonella elizabethae complex in Madagascar, hinting at a potential vector role for S. fonquerniei. Our analyses underscore the uniqueness of such ecologies for Bartonella species, which pose a variable range of potential zoonotic threats.

  10. A checklist of macroparasites of Liza haematocheila (Temminck & Schlegel) (Teleostei: Mugilidae).

    Science.gov (United States)

    Kostadinova, Aneta

    2008-12-31

    The mugilid fish Liza haematocheila (syn. Mugil soiuy), native to the Western North Pacific, provides opportunities to examine the changes of its parasite fauna after its translocation to the Sea of Azov and subsequent establishment in the Black Sea. However, the information on macroparasites of this host in both ranges of its current distribution comes from isolated studies published in difficult-to-access literature sources. Data from 53 publications, predominantly in Chinese, Russian and Ukrainian, were compiled from an extensive search of the literature and the Host-Parasite Database maintained up to 2005 at the Natural History Museum, London. The complete checklist of the metazoan parasites of L. haematocheila throughout its distributional range comprises summarised information for 69 nominal species of helminth and ectoparasitic crustacean parasites, from 45 genera and 27 families (370 host-parasite records in total) and includes the name of the parasite species, the area/locality of the host capture, and the author and date of the published record. The taxonomy is updated and the validity of the records and synonymies are critically evaluated. A comparison of the parasite faunas based on the records in the native and introduced/invasive range of L. haematocheila suggests that a large number of parasite species was 'lost' in the new distributional range whereas an even greater number was 'gained'. Although the present checklist provides information that will facilitate future studies, the interesting question of macroparasite faunal diversity in L. haematocheila in its natural and introduced/invasive ranges cannot be dealt with the current data because of unreliability associated with the large number of non-documented and questionable records. This stresses the importance of data quality analysis in using host-parasite database and checklist data.

  11. A checklist of macroparasites of Liza haematocheila (Temminck & Schlegel (Teleostei: Mugilidae

    Directory of Open Access Journals (Sweden)

    Kostadinova Aneta

    2008-12-01

    Full Text Available Abstract Background The mugilid fish Liza haematocheila (syn. Mugil soiuy, native to the Western North Pacific, provides opportunities to examine the changes of its parasite fauna after its translocation to the Sea of Azov and subsequent establishment in the Black Sea. However, the information on macroparasites of this host in both ranges of its current distribution comes from isolated studies published in difficult-to-access literature sources. Materials and methods Data from 53 publications, predominantly in Chinese, Russian and Ukrainian, were compiled from an extensive search of the literature and the Host-Parasite Database maintained up to 2005 at the Natural History Museum, London. Results The complete checklist of the metazoan parasites of L. haematocheila throughout its distributional range comprises summarised information for 69 nominal species of helminth and ectoparasitic crustacean parasites, from 45 genera and 27 families (370 host-parasite records in total and includes the name of the parasite species, the area/locality of the host capture, and the author and date of the published record. The taxonomy is updated and the validity of the records and synonymies are critically evaluated. A comparison of the parasite faunas based on the records in the native and introduced/invasive range of L. haematocheila suggests that a large number of parasite species was 'lost' in the new distributional range whereas an even greater number was 'gained'. Conclusion Although the present checklist provides information that will facilitate future studies, the interesting question of macroparasite faunal diversity in L. haematocheila in its natural and introduced/invasive ranges cannot be dealt with the current data because of unreliability associated with the large number of non-documented and questionable records. This stresses the importance of data quality analysis in using host-parasite database and checklist data.

  12. [The influence of weather conditions on the epidemiology of vector-borne diseases by the example of West Nile fever in Russia].

    Science.gov (United States)

    Platonov, A E

    2006-01-01

    Climate changes must influence the incidence of vector-borne infections, but their effects cannot be revealed due to lack of long-term observations. The impact of short-term weather changes may be used as a model. In Russia the biggest numbers of clinical cases of mosquito-borne West Nile infection were registered in 1999 in Volgograd and Astrakhan regions. The analysis of climatic dataset since 1900 shows that 1999 was the hottest year in Volgograd in the 20th century due to a very mild winter (December-March) and a rather hot summer (June-September). The author of the article puts forward a hypothesis that high winter temperatures favored the survival of over-wintering mosquito vectors, and high summer temperature facilitated the growth of the virus in the mosquitoes, as well as propagation of the mosquitoes themselves. The author assumes that conventional threshold temperatures for "beneficial for WNF conditions" in Russia are > or = 3 degrees C in winter, and > or = 22 degrees C in summer. These conditions coincided only in 1948 and 1999. In Astrakhan the "beneficial for WNF conditions" were registered in 30 out of 147 years of observation, and in 12 years between 1964 and 2003. This is not surprising that Astrakhan region is endemic for WNF in accordance with clinical and epidemiological data collected since the sixties. These findings give some hints on the WNF predisposing factors, as well as possibility of weather surveillance and prediction of WNF outbreaks in temperate climatic zones such as Southern Russia.

  13. Use of Google Earth to strengthen public health capacity and facilitate management of vector-borne diseases in resource-poor environments.

    Science.gov (United States)

    Lozano-Fuentes, Saul; Elizondo-Quiroga, Darwin; Farfan-Ale, Jose Arturo; Loroño-Pino, Maria Alba; Garcia-Rejon, Julian; Gomez-Carro, Salvador; Lira-Zumbardo, Victor; Najera-Vazquez, Rosario; Fernandez-Salas, Ildefonso; Calderon-Martinez, Joaquin; Dominguez-Galera, Marco; Mis-Avila, Pedro; Morris, Natashia; Coleman, Michael; Moore, Chester G; Beaty, Barry J; Eisen, Lars

    2008-09-01

    Novel, inexpensive solutions are needed for improved management of vector-borne and other diseases in resource-poor environments. Emerging free software providing access to satellite imagery and simple editing tools (e.g. Google Earth) complement existing geographic information system (GIS) software and provide new opportunities for: (i) strengthening overall public health capacity through development of information for city infrastructures; and (ii) display of public health data directly on an image of the physical environment. We used freely accessible satellite imagery and a set of feature-making tools included in the software (allowing for production of polygons, lines and points) to generate information for city infrastructure and to display disease data in a dengue decision support system (DDSS) framework. Two cities in Mexico (Chetumal and Merida) were used to demonstrate that a basic representation of city infrastructure useful as a spatial backbone in a DDSS can be rapidly developed at minimal cost. Data layers generated included labelled polygons representing city blocks, lines representing streets, and points showing the locations of schools and health clinics. City blocks were colour-coded to show presence of dengue cases. The data layers were successfully imported in a format known as shapefile into a GIS software. The combination of Google Earth and free GIS software (e.g. HealthMapper, developed by WHO, and SIGEpi, developed by PAHO) has tremendous potential to strengthen overall public health capacity and facilitate decision support system approaches to prevention and control of vector-borne diseases in resource-poor environments.

  14. Survey of vector-borne agents in feral cats and first report of Babesia gibsoni in cats on St Kitts, West Indies.

    Science.gov (United States)

    Kelly, Patrick John; Köster, Liza; Li, Jing; Zhang, Jilei; Huang, Ke; Branford, Gillian Carmichael; Marchi, Silvia; Vandenplas, Michel; Wang, Chengming

    2017-11-13

    As there is little data on vector-borne diseases of cats in the Caribbean region and even around the world, we tested feral cats from St Kitts by PCR to detect infections with Babesia, Ehrlichia and spotted fever group Rickettsia (SFGR) and surveyed them for antibodies to Rickettsia rickettsii and Ehrlichia canis. Whole blood was collected from apparently healthy feral cats during spay/ neuter campaigns on St Kitts in 2011 (N = 68) and 2014 (N = 52). Sera from the 52 cats from 2014 were used to detect antibodies to Ehrlichia canis and Rickettsia rickettsii using indirect fluorescent antibody tests and DNA extracted from whole blood of a total of 119 cats (68 from 2011, and 51 from 2014) was used for PCRs for Babesia, Ehrlichia and Rickettsia. We could not amplify DNA of SFG Rickettsia in any of the samples but found DNA of E. canis in 5% (6/119), Babesia vogeli in 13% (15/119), Babesia gibsoni in 4% (5/119), mixed infections with B. gibsoni and B. vogeli in 3% (3/119), and a poorly characterized Babesia sp. in 1% (1/119). Overall, 10% of the 52 cats we tested by IFA for E. canis were positive while 42% we tested by indirect fluorescent antibody (IFA) for R. rickettsii antigens were positive. Our study provides the first evidence that cats can be infected with B. gibsoni and also indicates that cats in the Caribbean may be commonly exposed to other vector-borne agents including SFGR, E. canis and B. vogeli. Animal health workers should be alerted to the possibility of clinical infections in their patients while public health workers should be alerted to the possibility that zoonotic SFGR are likely circulating in the region.

  15. Support for research towards understanding the population health vulnerabilities to vector-borne diseases: increasing resilience under climate change conditions in Africa.

    Science.gov (United States)

    Ramirez, Bernadette

    2017-12-12

    Diseases transmitted to humans by vectors account for 17% of all infectious diseases and remain significant public health problems. Through the years, great strides have been taken towards combatting vector-borne diseases (VBDs), most notably through large scale and coordinated control programmes, which have contributed to the decline of the global mortality attributed to VBDs. However, with environmental changes, including climate change, the impact on VBDs is anticipated to be significant, in terms of VBD-related hazards, vulnerabilities and exposure. While there is growing awareness on the vulnerability of the African continent to VBDs in the context of climate change, there is still a paucity of research being undertaken in this area, and impeding the formulation of evidence-based health policy change. One way in which the gap in knowledge and evidence can be filled is for donor institutions to support research in this area. The collaboration between the WHO Special Programme for Research and Training in Tropical Diseases (TDR) and the International Centre for Research and Development (IDRC) builds on more than 10 years of partnership in research capacity-building in the field of tropical diseases. From this partnership was born yet another research initiative on VBDs and the impact of climate change in the Sahel and sub-Saharan Africa. This paper lists the projects supported under this research initiative and provides a brief on some of the policy and good practice recommendations emerging from the ongoing implementation of the research projects. Data generated from the research initiative are expected to be uptaken by stakeholders (including communities, policy makers, public health practitioners and other relevant partners) to contribute to a better understanding of the impacts of social, environmental and climate change on VBDs(i.e. the nature of the hazard, vulnerabilities, exposure), and improve the ability of African countries to adapt to and reduce the

  16. Assessing bat droppings and predatory bird pellets for vector-borne bacteria: molecular evidence of bat-associated Neorickettsia sp. in Europe.

    Science.gov (United States)

    Hornok, Sándor; Szőke, Krisztina; Estók, Péter; Krawczyk, Aleksandra; Haarsma, Anne-Jifke; Kováts, Dávid; Boldogh, Sándor A; Morandini, Pál; Szekeres, Sándor; Takács, Nóra; Kontschán, Jenő; Meli, Marina L; Fernández de Mera, Isabel G; de la Fuente, José; Gyuranecz, Miklós; Sulyok, Kinga M; Weibel, Beatrice; Gönczi, Enikő; de Bruin, Arnout; Sprong, Hein; Hofmann-Lehmann, Regina

    2018-02-28

    In Europe, several species of bats, owls and kestrels exemplify highly urbanised, flying vertebrates, which may get close to humans or domestic animals. Bat droppings and bird pellets may have epidemiological, as well as diagnostic significance from the point of view of pathogens. In this work 221 bat faecal and 118 bird pellet samples were screened for a broad range of vector-borne bacteria using PCR-based methods. Rickettsia DNA was detected in 13 bat faecal DNA extracts, including the sequence of a rickettsial insect endosymbiont, a novel Rickettsia genotype and Rickettsia helvetica. Faecal samples of the pond bat (Myotis dasycneme) were positive for a Neorickettsia sp. and for haemoplasmas of the haemofelis group. In addition, two bird pellets (collected from a Long-eared Owl, Asio otus, and from a Common Kestrel, Falco tinnunculus) contained the DNA of a Rickettsia sp. and Anaplasma phagocytophilum, respectively. In both of these bird pellets the bones of Microtus arvalis were identified. All samples were negative for Borrelia burgdorferi s.l., Francisella tularensis, Coxiella burnetii and Chlamydiales. In conclusion, bats were shown to pass rickettsia and haemoplasma DNA in their faeces. Molecular evidence is provided for the presence of Neorickettsia sp. in bat faeces in Europe. In the evaluated regions bat faeces and owl/kestrel pellets do not appear to pose epidemiological risk from the point of view of F. tularensis, C. burnetii and Chlamydiales. Testing of bird pellets may provide an alternative approach to trapping for assessing the local occurrence of vector-borne bacteria in small mammals.

  17. Climate change and the spread of vector-borne diseases: using approximate Bayesian computation to compare invasion scenarios for the bluetongue virus vector Culicoides imicola in Italy.

    Science.gov (United States)

    Mardulyn, Patrick; Goffredo, Maria; Conte, Annamaria; Hendrickx, Guy; Meiswinkel, Rudolf; Balenghien, Thomas; Sghaier, Soufien; Lohr, Youssef; Gilbert, Marius

    2013-05-01

    Bluetongue (BT) is a commonly cited example of a disease with a distribution believed to have recently expanded in response to global warming. The BT virus is transmitted to ruminants by biting midges of the genus Culicoides, and it has been hypothesized that the emergence of BT in Mediterranean Europe during the last two decades is a consequence of the recent colonization of the region by Culicoides imicola and linked to climate change. To better understand the mechanism responsible for the northward spread of BT, we tested the hypothesis of a recent colonization of Italy by C. imicola, by obtaining samples from more than 60 localities across Italy, Corsica, Southern France, and Northern Africa (the hypothesized source point for the recent invasion of C. imicola), and by genotyping them with 10 newly identified microsatellite loci. The patterns of genetic variation within and among the sampled populations were characterized and used in a rigorous approximate Bayesian computation framework to compare three competing historical hypotheses related to the arrival and establishment of C. imicola in Italy. The hypothesis of an ancient presence of the insect vector was strongly favoured by this analysis, with an associated P ≥ 99%, suggesting that causes other than the northward range expansion of C. imicola may have supported the emergence of BT in southern Europe. Overall, this study illustrates the potential of molecular genetic markers for exploring the assumed link between climate change and the spread of diseases. © 2013 Blackwell Publishing Ltd.

  18. Canine vector-borne co-infections: Ehrlichia canis and Hepatozoon canis in the same host monocytes.

    Science.gov (United States)

    Baneth, Gad; Harrus, Shimon; Gal, Arnon; Aroch, Itamar

    2015-02-28

    The protozoon Hepatozoon canis and the rickettsia Ehrlichia canis are tick-borne pathogens, transmitted by Rhipicephalus sanguineus, which cause canine hepatozoonosis and canine monocytic ehrlichiosis, respectively. Co-infection of the same host monocytes with H. canis and E. canis confirmed by molecular characterization of the infecting agents and quantitative assessment of co-infected cells is described for the first time in three naturally-infected dogs. Blood smear evaluation indicated that at least 50% of the leukocytes infected with H. canis gamonts contained E. canis morulae. Co-infection of the same host cell demonstrated in this report suggests that infection with one pathogen may permit or enhance invasion or prolonged cellular survival of the other. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. The emergence and maintenance of vector-borne diseases in the khyber pakhtunkhwa province, and the federally administered tribal areas of pakistan.

    Science.gov (United States)

    Nieto, Nathan C; Khan, Khalid; Uhllah, Ghufran; Teglas, Mike B

    2012-01-01

    Human populations throughout much of the world are experiencing unprecedented changes in their relationship to the environment and their interactions with the animals with which so many humans are intimately dependent upon. These changes result not only from human induced changes in the climate, but also from population demographic changes due to wars, social unrest, behavioral changes resulting from cultural mixing, and large changes in land-use practices. Each of these social shifts can affect the maintenance and emergence of arthropod vectors disease or the pathogenic organisms themselves. A good example is the country of Pakistan, with a large rural population and developing urban economy, it also maintains a wide diversity of entomological disease vectors, including biting flies, mosquitoes, and ticks. Pathogens endemic to the region include the agents of piroplasmosis, rickettsiosis, spirochetosis, and viral hemorrhagic fevers and encephalitis. The northwestern region of the country, including the Khyber Pakhtunkhwa Province (KPK), formerly the North-West Frontier Provence (NWFP), and the Federally Administered Tribal Areas (FATA) are mountainous regions with a high degree of habitat diversity that has recently undergone a massive increase in human population density due to an immigrating refugee population from neighboring war-torn Afghanistan. Vector-borne diseases in people and livestock are common in KPK and FATA regions due to the limited use of vector control measures and access to livestock vaccines. The vast majority of people in this region live in abject poverty with >70% of the population living directly from production gained in animal husbandry. In many instances whole families live directly alongside their animal counterparts. In addition, there is little to no awareness of the threat posed by ticks and transmission of either zoonotic or veterinary pathogens. Recent emergence of Crimean-Congo hemorrhagic fever virus in rural populations

  20. Improving vector-borne pathogen surveillance: A laboratory-based study exploring the potential to detect dengue virus and malaria parasites in mosquito saliva.

    Science.gov (United States)

    Melanson, Vanessa R; Jochim, Ryan; Yarnell, Michael; Ferlez, Karen Bingham; Shashikumar, Soumya; Richardson, Jason H

    2017-01-01

    Vector-borne pathogen surveillance programmes typically rely on the collection of large numbers of potential vectors followed by screening protocols focused on detecting pathogens in the arthropods. These processes are laborious, time consuming, expensive, and require screening of large numbers of samples. To streamline the surveillance process, increase sample throughput, and improve cost-effectiveness, a method to detect dengue virus and malaria parasites (Plasmodium falciparum) by leveraging the sugar-feeding behaviour of mosquitoes and their habit of expectorating infectious agents in their saliva during feeding was investigated in this study. Dengue virus 2 (DENV-2) infected female Aedes aegypti mosquitoes and P. falciparum infected female Anopheles stephensi mosquitoes were allowed to feed on honey coated Flinders Technical Associates -FTA® cards dyed with blue food colouring. The feeding resulted in deposition of saliva containing either DENV-2 particles or P. falciparum sporozoites onto the FTA card. Nucleic acid was extracted from each card and the appropriate real-time PCR (qPCR) assay was run to detect the pathogen of interest. As little as one plaque forming unit (PFU) of DENV-2 and as few as 60 P. falciparum parasites deposited on FTA cards from infected mosquitoes were detected via qPCR. Hence, their use to collect mosquito saliva for pathogen detection is a relevant technique for vector surveillance. This study provides laboratory confirmation that FTA cards can be used to capture and stabilize expectorated DENV-2 particles and P. falciparum sporozoites from infectious, sugar-feeding mosquitoes in very low numbers. Thus, the FTA card-based mosquito saliva capture method offers promise to overcome current limitations and revolutionize traditional mosquito-based pathogen surveillance programmes. Field testing and further method development are required to optimize this strategy.

  1. Use of Remote Sensing Surveillance to Monitor Environmental Parameters Associated with Mosquito Abundance and Vector-borne Diseases

    Science.gov (United States)

    1996-01-01

    Lymphatic filariasis persists as a major cause of clinical morbidity and a significant impediment to socioeconomic development in various parts of the world including Egypt. In Egypt, filariasis has been endemic since time immemorial. Early epidemiologic studies identified Culex pipiens L. as the main vector of the disease and also showed that the geographic distribution of the disease is highly focal and concentrated in lower Egypt. Between 1950 and 1965, a large scale filariasis control program was carried out by the Egyptian Ministry of Health (EMOH) in the endemic areas. Control efforts led to a steady decrease of the disease in areas of the country previously identified as endemic. However, spot surveys conducted in various parts of the Nile Delta during the 1970's and 1980's revealed that the downward trend of the disease had stopped and that the prevalence and intensity of microfilaraemia had increased.

  2. Climate change and the emergence of vector-borne diseases in Europe: case study of dengue fever.

    Science.gov (United States)

    Bouzid, Maha; Colón-González, Felipe J; Lung, Tobias; Lake, Iain R; Hunter, Paul R

    2014-08-22

    Dengue fever is the most prevalent mosquito-borne viral disease worldwide. Dengue transmission is critically dependent on climatic factors and there is much concern as to whether climate change would spread the disease to areas currently unaffected. The occurrence of autochthonous infections in Croatia and France in 2010 has raised concerns about a potential re-emergence of dengue in Europe. The objective of this study is to estimate dengue risk in Europe under climate change scenarios. We used a Generalized Additive Model (GAM) to estimate dengue fever risk as a function of climatic variables (maximum temperature, minimum temperature, precipitation, humidity) and socioeconomic factors (population density, urbanisation, GDP per capita and population size), under contemporary conditions (1985-2007) in Mexico. We then used our model estimates to project dengue incidence under baseline conditions (1961-1990) and three climate change scenarios: short-term 2011-2040, medium-term 2041-2070 and long-term 2071-2100 across Europe. The model was used to calculate average number of yearly dengue cases at a spatial resolution of 10 × 10 km grid covering all land surface of the currently 27 EU member states. To our knowledge, this is the first attempt to model dengue fever risk in Europe in terms of disease occurrence rather than mosquito presence. The results were presented using Geographical Information System (GIS) and allowed identification of areas at high risk. Dengue fever hot spots were clustered around the coastal areas of the Mediterranean and Adriatic seas and the Po Valley in northern Italy. This risk assessment study is likely to be a valuable tool assisting effective and targeted adaptation responses to reduce the likely increased burden of dengue fever in a warmer world.

  3. Virtual globes and geospatial health: the potential of new tools in the management and control of vector-borne diseases

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    Anna-Sofie Stensgaard

    2009-05-01

    Full Text Available The rapidly growing field of three-dimensional software modeling of the Earth holds promise for applications in the geospatial health sciences. Easy-to-use, intuitive virtual globe technologies such as Google Earth™ enable scientists around the world to share their data and research results in a visually attractive and readily understandable fashion without the need for highly sophisticated geographical information systems (GIS or much technical assistance. This paper discusses the utility of the rapid and simultaneous visualization of how the agents of parasitic diseases are distributed, as well as that of their vectors and/or intermediate hosts together with other spatially-explicit information. The resulting better understanding of the epidemiology of infectious diseases, and the multidimensional environment in which they occur, are highlighted. In particular, the value of Google Earth™, and its web-based pendant Google Maps™, are reviewed from a public health view point, combining results from literature searches and experiences gained thus far from a multidisciplinary project aimed at optimizing schistosomiasis control and transmission surveillance in sub-Saharan Africa. Although the basic analytical capabilities of virtual globe applications are limited, we conclude that they have considerable potential in the support and promotion of the geospatial health sciences as a userfriendly, straightforward GIS tool for the improvement of data collation, visualization and exploration. The potential of these systems for data sharing and broad dissemination of scientific research and results is emphasized.

  4. Projected economic losses due to vector and vector-borne parasitic diseases in livestock of India and its significance in implementing the concept of integrated practices for vector management

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    B. W. Narladkar

    2018-02-01

    Full Text Available Broadly, species of arthropods infesting livestock are grouped into flies (biting and non-biting, fleas, lice (biting and sucking, ticks (soft and hard, and mites (burrowing, non-burrowing, and follicular. Among which, biting and non-biting flies and ticks are the potent vectors for many bacterial, viral, rickettsial, and protozoan diseases. Vectors of livestock are having economic significance on three points (1 direct losses from their bite and annoyance, worries, and psychological disturbances produced during the act of biting and feeding, (2 diseases they transmit, and (3 expenditure incurred for their control. Flies such as Culicoides spp. and Musca spp. and various species of hard ticks play important role in disease transmission in addition to their direct effects. For control of vectors, recent concept of integrated pest management (IPM provides the best solution and also addresses the problems related to acaricide resistance and environmental protection from hazardous chemicals. However, to successfully implement the concept of IPM, for each vector species, estimation of two monitory benchmarks, i.e., economic injury level (EIL and economic threshold level (ETL is essential prerequisite. For many vector species and under several circumstances, estimation of EIL and ETL appears to be difficult. Under such scenario, although may not be exact, an approximate estimate can be accrued by taking into account several criteria such as percent prevalence of vectors in a geographical area, percent losses produced, total livestock population, and current prices of livestock products such as milk, meat, and wool. Method for approximate estimation is first time described and elaborated in the present review article.

  5. Projected economic losses due to vector and vector-borne parasitic diseases in livestock of India and its significance in implementing the concept of integrated practices for vector management

    Science.gov (United States)

    Narladkar, B. W.

    2018-01-01

    Broadly, species of arthropods infesting livestock are grouped into flies (biting and non-biting), fleas, lice (biting and sucking), ticks (soft and hard), and mites (burrowing, non-burrowing, and follicular). Among which, biting and non-biting flies and ticks are the potent vectors for many bacterial, viral, rickettsial, and protozoan diseases. Vectors of livestock are having economic significance on three points (1) direct losses from their bite and annoyance, worries, and psychological disturbances produced during the act of biting and feeding, (2) diseases they transmit, and (3) expenditure incurred for their control. Flies such as Culicoides spp. and Musca spp. and various species of hard ticks play important role in disease transmission in addition to their direct effects. For control of vectors, recent concept of integrated pest management (IPM) provides the best solution and also addresses the problems related to acaricide resistance and environmental protection from hazardous chemicals. However, to successfully implement the concept of IPM, for each vector species, estimation of two monitory benchmarks, i.e., economic injury level (EIL) and economic threshold level (ETL) is essential prerequisite. For many vector species and under several circumstances, estimation of EIL and ETL appears to be difficult. Under such scenario, although may not be exact, an approximate estimate can be accrued by taking into account several criteria such as percent prevalence of vectors in a geographical area, percent losses produced, total livestock population, and current prices of livestock products such as milk, meat, and wool. Method for approximate estimation is first time described and elaborated in the present review article. PMID:29657396

  6. Potential Role of Diploscapter sp. Strain LKC25, a Bacterivorous Nematode from Soil, as a Vector of Food-Borne Pathogenic Bacteria to Preharvest Fruits and Vegetables

    Science.gov (United States)

    Gibbs, Daunte S.; Anderson, Gary L.; Beuchat, Larry R.; Carta, Lynn K.; Williams, Phillip L.

    2005-01-01

    Diploscapter, a thermotolerant, free-living soil bacterial-feeding nematode commonly found in compost, sewage, and agricultural soil in the United States, was studied to determine its potential role as a vehicle of Salmonella enterica serotype Poona, enterohemorrhagic Escherichia coli O157:H7, and Listeria monocytogenes in contaminating preharvest fruits and vegetables. The ability of Diploscapter sp. strain LKC25 to survive on agar media, in cow manure, and in composted turkey manure and to be attracted to, ingest, and disperse food-borne pathogens inoculated into soil or a mixture of soil and composted turkey manure was investigated. Diploscapter sp. strain LKC25 survived and reproduced in lawns of S. enterica serotype Poona, E. coli O157:H7, and L. monocytogenes on agar media and in cow manure and composted turkey manure. Attraction of Diploscapter sp. strain LKC25 to colonies of pathogenic bacteria on tryptic soy agar within 10, 20, 30, and 60 min and 24 h was determined. At least 85% of the worms initially placed 0.5 to 1 cm away from bacterial colonies migrated to the colonies within 1 h. Within 24 h, ≥90% of the worms were embedded in colonies. The potential of Diploscapter sp. strain LKC25 to shed pathogenic bacteria after exposure to bacteria inoculated into soil or a mixture of soil and composted turkey manure was investigated. Results indicate that Diploscapter sp. strain LKC25 can shed pathogenic bacteria after exposure to pathogens in these milieus. They also demonstrate its potential to serve as a vector of food-borne pathogenic bacteria in soil, with or without amendment with compost, to the surface of preharvest fruits and vegetables in contact with soil. PMID:15870330

  7. Study of the climatic change impact on vector-borne diseases in West Africa: the case of tick-borne borreliosis and malaria; Etude de l'impact du changement climatique sur les maladies a transmission vectorielle en Afrique de l'Ouest: le cas de la borreliose a tiques et du paludisme

    Energy Technology Data Exchange (ETDEWEB)

    Trape, J.F

    2005-04-15

    Malaria and tick-borne borreliosis are the two first causes of morbidity due to vector-borne diseases in a large part of Sudan-sahelian West Africa. They are also the two tropical diseases which have been the most affected by climatic change in recent years. In the case of tick-borne borreliosis it has been shown in Senegal that the persistence of drought since the years 70 has been associated with a considerable extension of the geographic range of diseases and the vector tick A-sonrai, a species that was in the past limited to the Sahara and Sahel. In the case of malaria, drought has strongly reduced in these same regions of Africa the distribution, abundance and infection rate of Anopheline mosquitoes, but without any significant reduction of the burden of malaria for most populations concerned. The emergence and spread of Plasmodium falciparum resistance to antimalarial drugs only explain part of this phenomenon. (A.L.B.)

  8. Aquatic Insect from Iran for Possible Use of Biological Control of Main Vector-Borne Disease of Malaria and Water Indicator of Contamination

    Directory of Open Access Journals (Sweden)

    Zahra Saeidi

    2018-03-01

    Full Text Available Iran has a wide variety of zoogeographical regions and different seasons. Here are some important mosquito-borne diseases. Mosquitoes normally live in waters. Its aquatic insect fauna is highly unexplored. To being resolved this faunal gap, a variety of literature records from previous century in different parts of Iran was reviewed. In some southern and southeastern foci in Iran, Malaria is still a main endemic disease which is unstable with two seasonal spring and autumn peaks even though Iran is lunching Malaria elimination. This review article showed the wide variety of aquatic insects throughout the country. Researchers can discuss water pollutant and its quality by using aquatic insect fauna as well as biological control for vectors. Types of aquatic in­sects and macroinvertebrates sampling can be useful for water quality monitoring as indicators. Looking at aquatic insects’ life in water could be one of the most cost-effective and the easiest method to assess the water contaminations by different pollutants and will provide a guideline for scientific communities and environmental agencies for decision making.

  9. Critical analysis of vector-borne infections in dogs: Babesia vogeli, Babesia gibsoni, Ehrlichia canis and Hepatozoon canis in Punjab, India.

    Science.gov (United States)

    Singla, Lachhman Das; Sumbria, Deepak; Mandhotra, Ajay; Bal, M S; Kaur, Paramjit

    2016-12-01

    There are few published studies on various vector borne diseases of dogs in India and most depict clinical infection in dogs, diagnosed by observation of the haemopathogens in stained blood smears. This study provides the first report regarding molecular confirmation and ancestral relationship analysis of blood smears positive cases of assorted haemopathogens in Punjab province of India. On blood smear examination, haemopathogens were observed in 124 out of 778 (15.95%, 95% CI: 13.53- 18.68) blood smears. Further polymerase chain reactions (PCR) was used on bloods smear positive cases to validate the results. Out of 778 blood samples, Babesia gibsoni was most common parasite infecting dogs (15.04%, 95% CI: 12.7-17.72), followed by Ehrlichia canis (0.39%, 95% CI: 0.0-1.13), infection of Babesia vogeli and Hepatozoon canis was same (0.26%, 95% CI: 0.0-0.9). Among various risk factors studied (age, sex, season), prevalence of infection was non-significantly higher in 1-2 year of age group (19.88%, 95% CI: 14.45-26.71), regarding sex same prevalence was recorded (15.94%), and chances of infection was highest in pre-monsoon i.e. summer (18.26%, 95% CI: 14.49-22.76). Phylogenetic analysis revealed ancestral background of Ludhiana isolates of B. vogeli, B. gibsoni, H. canis, and E. canis with the isolates of Philippines, Mongolia and Tunisia.

  10. Divergent Macroparasite Infections in Parapatric Swiss Lake-Stream Pairs of Threespine Stickleback (Gasterosteus aculeatus.

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    Anssi Karvonen

    Full Text Available Spatial heterogeneity in diversity and intensity of parasitism is a typical feature of most host-parasite interactions, but understanding of the evolutionary implications of such variation is limited. One possible outcome of infection heterogeneities is parasite-mediated divergent selection between host populations, ecotypes or species which may facilitate the process of ecological speciation. However, very few studies have described infections in population-pairs along the speciation continuum from low to moderate or high degree of genetic differentiation that would address the possibility of parasite-mediated divergent selection in the early stages of the speciation process. Here we provide an example of divergent parasitism in freshwater fish ecotypes by examining macroparasite infections in threespine stickleback (Gasterosteus aculeatus of four Swiss lake systems each harbouring parapatric lake-stream ecotype pairs. We demonstrate significant differences in infections within and between the pairs that are driven particularly by the parasite taxa transmitted to fish from benthic invertebrates. The magnitude of the differences tended to correlate positively with the extent of neutral genetic differentiation between the parapatric lake and stream populations of stickleback, whereas no such correlation was found among allopatric populations from similar or contrasting habitats. This suggests that genetic differentiation is unrelated to the magnitude of parasite infection contrasts when gene flow is constrained by geographical barriers while in the absence of physical barriers, genetic differentiation and the magnitude of differences in infections tend to be positively correlated.

  11. Divergent Macroparasite Infections in Parapatric Swiss Lake-Stream Pairs of Threespine Stickleback (Gasterosteus aculeatus).

    Science.gov (United States)

    Karvonen, Anssi; Lucek, Kay; Marques, David A; Seehausen, Ole

    2015-01-01

    Spatial heterogeneity in diversity and intensity of parasitism is a typical feature of most host-parasite interactions, but understanding of the evolutionary implications of such variation is limited. One possible outcome of infection heterogeneities is parasite-mediated divergent selection between host populations, ecotypes or species which may facilitate the process of ecological speciation. However, very few studies have described infections in population-pairs along the speciation continuum from low to moderate or high degree of genetic differentiation that would address the possibility of parasite-mediated divergent selection in the early stages of the speciation process. Here we provide an example of divergent parasitism in freshwater fish ecotypes by examining macroparasite infections in threespine stickleback (Gasterosteus aculeatus) of four Swiss lake systems each harbouring parapatric lake-stream ecotype pairs. We demonstrate significant differences in infections within and between the pairs that are driven particularly by the parasite taxa transmitted to fish from benthic invertebrates. The magnitude of the differences tended to correlate positively with the extent of neutral genetic differentiation between the parapatric lake and stream populations of stickleback, whereas no such correlation was found among allopatric populations from similar or contrasting habitats. This suggests that genetic differentiation is unrelated to the magnitude of parasite infection contrasts when gene flow is constrained by geographical barriers while in the absence of physical barriers, genetic differentiation and the magnitude of differences in infections tend to be positively correlated.

  12. Plastination of macroparasites: An eco-friendly method of long-term preservation.

    Science.gov (United States)

    Kumar, Niranjan; Das, Bhupamani; Solanki, Jayesh B; Jadav, Mehul M; Menaka, Ramasamy

    2017-11-01

    Preservation of macroparasites by infiltrating the polymer in the tissues can defy the inherited shortcoming of classical wet preservation method. Preservation was done by infiltrating the melamine alone or with xylene (MX)/chloroform (MC)/turpentine oil (MT) in 1:1 and hardener (MH) in 9:1 ratio in the tissues of the gross specimen of the animal parasites. The plastinated models withstand the process of microbial decomposition, and remain intact in the environmental conditions. The polymer mixture resists the entry of the water molecule, and model dried just after taking out it from the water tank. Overall, the plastinated parasites were dry, non-sticky, glossy, odorless, chemical free, and harmless, to some extent flexible, with detectable morphological structure, and retain their natural form but lost their natural color. Full marks were assigned to the degree of dryness, non-stickiness, and odorlessness to the model plastinated in different solutions on a five-point scale. For flexibility, the score was 1.2, 2.2, and 2.4 for the plastinated model in melamine/MH, MX/MC, and MT solutions, respectively. The average score of glossiness was 4.6 and 5 for the specimen plastinated in melamine/MH and MX/MC/MT solutions, respectively. The degree of dryness, glossiness, stickiness, and flexibility varies non-significantly, with the polymer mixtures used. The prepared model can be used to educate the students/general mass population.

  13. Plastination of macroparasites: An eco-friendly method of long-term preservation

    Directory of Open Access Journals (Sweden)

    Niranjan Kumar

    2017-11-01

    Full Text Available Aim: Preservation of macroparasites by infiltrating the polymer in the tissues can defy the inherited shortcoming of classical wet preservation method. Materials and Methods: Preservation was done by infiltrating the melamine alone or with xylene (MX/chloroform (MC/turpentine oil (MT in 1:1 and hardener (MH in 9:1 ratio in the tissues of the gross specimen of the animal parasites. Results: The plastinated models withstand the process of microbial decomposition, and remain intact in the environmental conditions. The polymer mixture resists the entry of the water molecule, and model dried just after taking out it from the water tank. Overall, the plastinated parasites were dry, non-sticky, glossy, odorless, chemical free, and harmless, to some extent flexible, with detectable morphological structure, and retain their natural form but lost their natural color. Full marks were assigned to the degree of dryness, non-stickiness, and odorlessness to the model plastinated in different solutions on a five-point scale. For flexibility, the score was 1.2, 2.2, and 2.4 for the plastinated model in melamine/MH, MX/MC, and MT solutions, respectively. The average score of glossiness was 4.6 and 5 for the specimen plastinated in melamine/MH and MX/MC/MT solutions, respectively. The degree of dryness, glossiness, stickiness, and flexibility varies non-significantly, with the polymer mixtures used. Conclusion: The prepared model can be used to educate the students/general mass population.

  14. [Tick-borne diseases].

    Science.gov (United States)

    Tissot Dupont, H; Raoult, D

    1993-05-01

    Due to their worldwide distribution, from hottest to coldest climates, and due to their behaviour, ticks are capable of transmitting numerous human and animal bacterial viral or parasitous diseases. Depending on the disease, they play the role of biological vector or intermediate host. In France, six tick borne diseases are of epidemiologic importance. Q fever (not often tick-borne), Mediterranean Spotted Fever, Lyme disease, Turalemia (human and animal), Babesiosis and Tick-borne Viral Encephalitis.

  15. Combining dispersion modelling with synoptic patterns to understand the wind-borne transport into the UK of the bluetongue disease vector.

    Science.gov (United States)

    Burgin, Laura; Ekström, Marie; Dessai, Suraje

    2017-07-01

    Bluetongue, an economically important animal disease, can be spread over long distances by carriage of insect vectors (Culicoides biting midges) on the wind. The weather conditions which influence the midge's flight are controlled by synoptic scale atmospheric circulations. A method is proposed that links wind-borne dispersion of the insects to synoptic circulation through the use of a dispersion model in combination with principal component analysis (PCA) and cluster analysis. We illustrate how to identify the main synoptic situations present during times of midge incursions into the UK from the European continent. A PCA was conducted on high-pass-filtered mean sea-level pressure data for a domain centred over north-west Europe from 2005 to 2007. A clustering algorithm applied to the PCA scores indicated the data should be divided into five classes for which averages were calculated, providing a classification of the main synoptic types present. Midge incursion events were found to mainly occur in two synoptic categories; 64.8% were associated with a pattern displaying a pressure gradient over the North Atlantic leading to moderate south-westerly flow over the UK and 17.9% of the events occurred when high pressure dominated the region leading to south-easterly or easterly winds. The winds indicated by the pressure maps generally compared well against observations from a surface station and analysis charts. This technique could be used to assess frequency and timings of incursions of virus into new areas on seasonal and decadal timescales, currently not possible with other dispersion or biological modelling methods.

  16. Acquired and introduced macroparasites of the invasive Cuban treefrog, Osteopilus septentrionalis

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    Nicole Ortega

    2015-12-01

    Full Text Available Because shifts in host–parasite relationships can alter host populations, attention should be given to the parasites that introduced species take with them or acquire in their introduced range. The Cuban treefrog, Osteopilus septentrionalis, is a successful invasive species in Florida with its parasites in the native range being well-documented, but there is a void in the literature regarding what parasites were lost or introduced in its expansion. We necropsied 330 O. septentrionalis from Tampa, FL and compared their macroparasites to those of O. septentrionalis in their native range and to the parasites of anurans native to the Tampa, FL area to determine the species O. septentrionalis likely introduced or acquired in Florida. At least nine parasite species (Aplectana sp., Oswaldocruzia lenteixeirai, Cylindrotaenia americana, Physaloptera sp., Rhabdias sp., Centrorhynchus sp., unidentified trematode metacercariae, unidentified larval acuariids, and unidentified pentastomids were isolated. We found no differences in parasite communities of adult male and female frogs, which averaged 19.36 parasite individuals and 1.39 parasite species per adult frog, and had an overall prevalence of 77.52%. Acuariid larvae were likely acquired by O. septentrionalis in FL because they are not found in their native range. O. lenteixeirai was likely introduced because it is commonly reported in O. septentrionalis' native range but has never been reported in FL-native anurans. Aplectana sp. is also likely introduced because it has been reported in several anurans in Cuba but only reported once in Florida. O. septentrionalis tended to harbor fewer of its native parasites in the introduced range, which is consistent with the enemy release hypothesis and potentially creates an immunological advantage for this invasive host. Because native populations can be threatened by introduced parasites, there is a need to further explore the frequency and rate at which

  17. Support for research towards understanding the population health vulnerabilities to vector-borne diseases: increasing resilience under climate change conditions in Africa

    Institute of Scientific and Technical Information of China (English)

    Bernadette Ramirez

    2017-01-01

    Background:Diseases transmitted to humans by vectors account for 17% of all infectious diseases and remain significant public health problems.Through the years,great strides have been taken towards combatting vectorborne diseases (VBDs),most notably through large scale and coordinated control programmes,which have contributed to the decline of the global mortality attributed to VBDs.However,with environmental changes,including climate change,the impact on VBDs is anticipated to be significant,in terms of VBD-related hazards,vulnerabilities and exposure.While there is growing awareness on the vulnerability of the African continent to VBDs in the context of climate change,there is still a paucity of research being undertaken in this area,and impeding the formulation of evidence-based health policy change.Main body:One way in which the gap in knowledge and evidence can be filled is for donor institutions to support research in this area.The collaboration between the WHO Special Programme for Research and Training in Tropical Diseases (TDR) and the International Centre for Research and Development (IDRC) builds on more than 10 years of partnership in research capacity-building in the field of tropical diseases.From this partnership was born yet another research initiative on VBDs and the impact of climate change in the Sahel and sub-Saharan Africa.This paper lists the projects supported under this research initiative and provides a brief on some of the policy and good practice recommendations emerging from the ongoing implementation of the research projects.Conclusion:Data generated from the research initiative are expected to be uptaken by stakeholders (including communities,policy makers,public health practitioners and other relevant partners) to contribute to a better understanding of the impacts of social,environmental and climate change on VBDs(i.e.the nature of the hazard,vulnerabilities,exposure),and improve the ability of African countries to adapt to and

  18. Vector-borne pathogens in dogs from Costa Rica: first molecular description of Babesia vogeli and Hepatozoon canis infections with a high prevalence of monocytic ehrlichiosis and the manifestations of co-infection.

    Science.gov (United States)

    Rojas, Alicia; Rojas, Diana; Montenegro, Víctor; Gutiérrez, Ricardo; Yasur-Landau, Daniel; Baneth, Gad

    2014-01-31

    Infection with canine vector-borne pathogens was evaluated in dogs from four different regions of Costa Rica by PCR. Demographic data, clinical signs, packed cell volume values, and the presence of tick infestation were recorded for each dog. Forty seven percent (69/146) of the dogs were infected with at least one pathogen and 12% were co-infected with two pathogens. Ehrlichia canis was detected in 34%, Anaplasma platys in 10%, Babesia vogeli in 8%, and Hepatozoon canis in 7.5% of the blood samples. No infection was detected with Leishmania spp. in blood, skin scrapings or conjunctival swabs. Thirty percent of the dogs presented at least one clinical sign compatible with vector-borne disease, and of those, 66% were infected with a pathogen. Subclinical infections were determined in 58% of the infected dogs including 82% (9/11), 58% (29/50), 42% (5/12) and 36% (5/14) of the dogs with H. canis, E. canis, B. vogeli and A. platys infections, respectively. A distinct relationship was found between infection and anemia. The mean PCV values were 34.4% in dogs with no infection, 31.5% in those who had a single infection and 23% in those with co-infection. Co-infected dogs had significantly lower PCV values compared to non-infected and single-infected dogs (pcanis were significantly associated with R. sanguineus s.l. infestation (pcanis in Costa Rica as well as in Central America. The results of this study indicate that multiple vector-borne pathogens responsible for severe diseases infect dogs in Costa Rica and therefore, increased owner and veterinarian awareness are needed. Moreover, prevention of tick infestation is recommended to decrease the threat of these diseases to the canine population. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Neem by-products in the fight against mosquito-borne diseases: Biotoxicity of neem cake fractions towards the rural malaria vector Anopheles culicifacies (Diptera: Culicidae

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    Balamurugan Chandramohan

    2016-06-01

    Conclusions: Overall, this study suggests that the methanolic fractions of neem cake may be considered as a new and cheap source of highly effective compounds against the rural malaria vector An. culicifacies.

  20. The wild life of tick-borne pathogens

    NARCIS (Netherlands)

    Hofmeester, Tim R.

    2016-01-01

    Diseases that are transmitted by arthropod vectors from animal hosts to humans – so called zoonotic vector-borne diseases – have increased in incidence in the last decades. In North America and Europe, tick-borne pathogens cause the majority of vector-borne diseases, including Lyme borreliosis

  1. The wild life of tick-borne pathogens

    OpenAIRE

    Hofmeester, Tim R.

    2016-01-01

    Diseases that are transmitted by arthropod vectors from animal hosts to humans – so called zoonotic vector-borne diseases – have increased in incidence in the last decades. In North America and Europe, tick-borne pathogens cause the majority of vector-borne diseases, including Lyme borreliosis and tick-borne encephalitis. The pathogens causing these diseases are transmitted by tick species within the Ixodes ricinus complex. These are generalist ticks that have a multi-year lifecycle with thre...

  2. The risk of vector-borne infections in sled dogs associated with existing and new endemic areas in Poland. Part 2: Occurrence and control of babesiosis in a sled dog kennel during a 13-year-long period.

    Science.gov (United States)

    Bajer, Anna; Mierzejewska, Ewa J; Rodo, Anna; Welc-Falęciak, Renata

    2014-05-28

    The achievements of sled dogs in competitions depend both on their training and on their health. Vector-borne infections may lead to anemia, affect joints or heart muscles or even cause death. Canine babesiosis is an emerging, quickly spreading tick-borne disease in Central Europe. Over a 13-year period (2000-2012) the occurrence of babesiosis cases was analyzed in one sled dog kennel situated in Kury, a village near Tłuszcz (N 52°24'56.78″, E 21°30'37.55″) in Central Poland. Twenty cases/episodes of babesiosis were noted among the 10-12 dogs living in the kennel. In 2000-2004, no cases of babesiosis were noted; the first two cases were noted in April 2005. Since that time, only one dog remained uninfected; 6 dogs were infected once, 3 dogs demonstrated symptoms of babesiosis twice, one dog was infected three times and one dog had it five times. Babesiosis appeared in Spring and Autumn, despite the application of anti-tick treatment. No fatal cases were recorded, but in one case a splenectomy was performed due to splenomegaly and spleen rupture. Additionally, the abundance of the main Babesia canis vector, the Dermacentor reticulatus tick, was estimated and monitored during a 4-year period (2008-2012) close to the dog kennel. The abundance of questing ticks was high in 2008 and 2009, but dropped by 10-fold between 2010 and 2012, when the abandoned meadow was cut and used as horse pasture by the local farmer. The regular occurrence, typical seasonal pattern and identification of B. canis DNA in questing tick from this locality confirmed the establishment of a new hyper enzootic region for canine babesiosis. The effectiveness and schedule of applied preventive measures were discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Vector-borne parasitic infections in dogs in the Baltic and Nordic countries: A questionnaire study to veterinarians on canine babesiosis and infections with Dirofilaria immitis and Dirofilaria repens.

    Science.gov (United States)

    Tiškina, Valentina; Jokelainen, Pikka

    2017-09-15

    Canine vector-borne diseases have been spreading northwards in Europe, and canine babesiosis and infections with Dirofilaria immitis (heartworm) and Dirofilaria repens have been diagnosed also in the Baltic and the Nordic countries. We used an online questionnaire to survey how large a proportion of veterinarians in the Baltic (Estonia, Latvia, and Lithuania) and the Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden) saw canine babesiosis cases and dogs infected with D. immitis and D. repens in 2016. In addition, questions regarding transmission, zoonotic potential, clinical signs, and treatment of the infections were asked. The questionnaire was completed by 122 veterinarians. In 2016, 23% of them had seen at least one case of canine babesiosis, 15% at least one dog with D. immitis infection, and 9% at least one dog with D. repens infection. A veterinarian working in the Baltic countries had 12.2 times higher odds to have seen a canine babesiosis case and 9.3 times higher odds to have seen a dog with D. repens infection than a veterinarian working in the Nordic countries did. While 48% of the veterinarians knew that canine babesiosis is not considered a zoonosis, 26% knew that D. immitis is zoonotic and 34% knew that D. repens is zoonotic. The results suggested that autochthonous cases of the three vector-borne parasitic infections were seen by veterinarians in the Baltic countries, whereas most cases seen by veterinarians in the Nordic countries appeared to be imported. A substantial proportion of the veterinarians did not know whether the parasites are zoonotic. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Sociocultural factors influencing control and prevention of vector-borne diseases: The case of zika in Santa Marta (Colombia, 2015-2016.

    Directory of Open Access Journals (Sweden)

    Astrid Lorena Perafán Ledezma

    2017-03-01

    Full Text Available Durante el año 2016, el grupo de Investigación en Diversidad Humana (IDHUM de la Universidad del Magdalena inició un proceso de investigación sobre conocimientos, percepciones y prácticas en torno al Zika y su vector en la ciudad de Santa Marta. Dado lo relevante del tema para la salud pública, consideramos pertinente comunicar a través de este medio algunos de nuestros hallazgos antes de terminar la investigación y que esta se publique en su totalidad.

  5. Seasonal patterns of hormones, macroparasites, and microparasites in wild African ungulates: the interplay among stress, reproduction, and disease.

    Science.gov (United States)

    Cizauskas, Carrie A; Turner, Wendy C; Pitts, Neville; Getz, Wayne M

    2015-01-01

    Sex hormones, reproductive status, and pathogen load all affect stress. Together with stress, these factors can modulate the immune system and affect disease incidence. Thus, it is important to concurrently measure these factors, along with their seasonal fluctuations, to better understand their complex interactions. Using steroid hormone metabolites from fecal samples, we examined seasonal correlations among zebra and springbok stress, reproduction, gastrointestinal (GI) parasite infections, and anthrax infection signatures in zebra and springbok in Etosha National Park (ENP), Namibia, and found strong seasonal effects. Infection intensities of all three GI macroparasites examined (strongyle helminths, Strongyloides helminths, and Eimeria coccidia) were highest in the wet season, concurrent with the timing of anthrax outbreaks. Parasites also declined with increased acquired immune responses. We found hormonal evidence that both mares and ewes are overwhelmingly seasonal breeders in ENP, and that reproductive hormones are correlated with immunosuppression and higher susceptibility to GI parasite infections. Stress hormones largely peak in the dry season, particularly in zebra, when parasite infection intensities are lowest, and are most strongly correlated with host mid-gestation rather than with parasite infection intensity. Given the evidence that GI parasites can cause host pathology, immunomodulation, and immunosuppression, their persistence in ENP hosts without inducing chronic stress responses supports the hypothesis that hosts are tolerant of their parasites. Such tolerance would help to explain the ubiquity of these organisms in ENP herbivores, even in the face of their potential immunomodulatory trade-offs with anti-anthrax immunity.

  6. Seasonal patterns of hormones, macroparasites, and microparasites in wild African ungulates: the interplay among stress, reproduction, and disease.

    Directory of Open Access Journals (Sweden)

    Carrie A Cizauskas

    Full Text Available Sex hormones, reproductive status, and pathogen load all affect stress. Together with stress, these factors can modulate the immune system and affect disease incidence. Thus, it is important to concurrently measure these factors, along with their seasonal fluctuations, to better understand their complex interactions. Using steroid hormone metabolites from fecal samples, we examined seasonal correlations among zebra and springbok stress, reproduction, gastrointestinal (GI parasite infections, and anthrax infection signatures in zebra and springbok in Etosha National Park (ENP, Namibia, and found strong seasonal effects. Infection intensities of all three GI macroparasites examined (strongyle helminths, Strongyloides helminths, and Eimeria coccidia were highest in the wet season, concurrent with the timing of anthrax outbreaks. Parasites also declined with increased acquired immune responses. We found hormonal evidence that both mares and ewes are overwhelmingly seasonal breeders in ENP, and that reproductive hormones are correlated with immunosuppression and higher susceptibility to GI parasite infections. Stress hormones largely peak in the dry season, particularly in zebra, when parasite infection intensities are lowest, and are most strongly correlated with host mid-gestation rather than with parasite infection intensity. Given the evidence that GI parasites can cause host pathology, immunomodulation, and immunosuppression, their persistence in ENP hosts without inducing chronic stress responses supports the hypothesis that hosts are tolerant of their parasites. Such tolerance would help to explain the ubiquity of these organisms in ENP herbivores, even in the face of their potential immunomodulatory trade-offs with anti-anthrax immunity.

  7. Spatial Analysis of West Nile Virus: Predictive Risk Modeling of a Vector-borne Infectious Disease in Illinois by Means of NASA Earth Observation Systems

    Science.gov (United States)

    Renneboog, Nathan; Gathings, David; Hemmings, Sarah; Makasa, Emmanuel; Omer, Wigdan; Tipre, Meghan; Wright, Catherine; McAllister, Marilyn; Luvall, Jeffrey C.

    2009-01-01

    West Nile Virus is a mosquito-borne virus of the family Flaviviridae. It infects birds and various mammals, including humans, and can cause encephalitis that may prove fatal, notably among vulnerable populations. Since its identification in New York City in 1999, WNV has become established in a broad range of ecological settings throughout North America, infecting more than 25,300 people and killing 1133 as of 2008 (CDC,2009). WNV is transmitted by mosquitoes that feed on infected birds. As a result, the degree of human infection depends on local ecology and human exposure. This study hypothesizes that remote sensing and GIS can be used to analyze environmental determinants of WNV transmission, such as climate, elevation, land cover, and vegetation densities, to map areas of WNV risk for surveillance and intervention.

  8. Dynamic properties of the Sulfolobus CRISPR/Cas and CRISPR/Cmr systems when challenged with vector-borne viral and plasmid genes and protospacers

    DEFF Research Database (Denmark)

    Guðbergsdóttir, Sóley Ruth; Deng, Ling; Chen, Zhengjun

    2011-01-01

    The adaptive immune CRISPR/Cas and CRISPR/Cmr systems of the crenarchaeal thermoacidophile Sulfolobus were challenged by a variety of viral and plasmid genes, and protospacers preceded by different dinucleotide motifs. The genes and protospacers were constructed to carry sequences matching...... individual spacers of CRISPR loci, and a range of mismatches were introduced. Constructs were cloned into vectors carrying pyrE/pyrF genes and transformed into uracil auxotrophic hosts derived from Sulfolobus solfataricus P2 or Sulfolobus islandicus REY15A. Most constructs, including those carrying different...... protospacer mismatches, yielded few viable transformants. These were shown to carry either partial deletions of CRISPR loci, covering a broad spectrum of sizes and including the matching spacer, or deletions of whole CRISPR/Cas modules. The deletions occurred independently of whether genes or protospacers...

  9. Regional Warming and Emerging Vector-Borne Zoonotic Dirofilariosis in the Russian Federation, Ukraine, and Other Post-Soviet States from 1981 to 2011 and Projection by 2030

    Directory of Open Access Journals (Sweden)

    Vladimir Kartashev

    2014-01-01

    Full Text Available We analyze through a climatic model the influence of regional warming on the geographical spreading and potential risk of infection of human dirofilariosis in Russia, Ukraine, and other post-Soviet states from 1981 to 2011 and estimate the situation by 2030. The model correctly predicts the spatiotemporal location of 97.10% of 2154 clinical cases reported in the area during the studied period, identified by a retrospective review of the literature. There exists also a significant correlation between annual predicted Dirofilaria generations and calculated morbidity. The model states the progressive increase of 14.8% in the potential transmission area, up to latitude 64°N, and 14.7% in population exposure. By 2030 an increase of 18.5% in transmission area and 10.8% in population exposure is expected. These findings strongly suggest the influence of global warming in both geographical spreading and increase in the number of Dirofilaria generations. The results should alert about the epidemiological behavior of dirofilariosis and other mosquito-borne diseases in these and other countries with similar climatic characteristics.

  10. Regional warming and emerging vector-borne zoonotic dirofilariosis in the Russian Federation, Ukraine, and other post-Soviet states from 1981 to 2011 and projection by 2030.

    Science.gov (United States)

    Kartashev, Vladimir; Afonin, Alexandr; González-Miguel, Javier; Sepúlveda, Rosa; Simón, Luis; Morchón, Rodrigo; Simón, Fernando

    2014-01-01

    We analyze through a climatic model the influence of regional warming on the geographical spreading and potential risk of infection of human dirofilariosis in Russia, Ukraine, and other post-Soviet states from 1981 to 2011 and estimate the situation by 2030. The model correctly predicts the spatiotemporal location of 97.10% of 2154 clinical cases reported in the area during the studied period, identified by a retrospective review of the literature. There exists also a significant correlation between annual predicted Dirofilaria generations and calculated morbidity. The model states the progressive increase of 14.8% in the potential transmission area, up to latitude 64 °N, and 14.7% in population exposure. By 2030 an increase of 18.5% in transmission area and 10.8% in population exposure is expected. These findings strongly suggest the influence of global warming in both geographical spreading and increase in the number of Dirofilaria generations. The results should alert about the epidemiological behavior of dirofilariosis and other mosquito-borne diseases in these and other countries with similar climatic characteristics.

  11. Species composition and fauna distribution of mosquitoes (Diptera: Culicidae and its importance for vector-borne diseases in a rural area of Central Western - Mato Grosso, Brazil

    Directory of Open Access Journals (Sweden)

    Fábio Alexandre Leal-Santos

    2017-08-01

    Full Text Available Abstract. This study describes ecological data obtained in a rural area in the State of Mato Grosso, including the insects belonging to the family Culicidae, especially those framed as potential vectors of tropical diseases. In 2015, we collected adult mosquitoes in fragments of forest in a rural area located in Mato Grosso Central West of Brazil. We captured 18,256 mosquitoes of the sub-families Culicinae and Anophelinae and have identified 34 species belonging to 12 genera: Aedes (1 species, Anopheles (8 species, Coquillettidia (1 species, Haemagogus (1 species, Culex (5 species, Psorophora  (5 species, Ochlerotatus (4 species, Deinocerites (1 species,  Mansonia (4 species, Sabethes (2 species, Limatus (1 species, Wyeomyia (1 species. The family Culicidae presented high richness and abundance, established by diversity indexes (Margalef α =3.26; Shannon H' = 2.09; Simpson D = 0.19 with dominance of the species Anopheles (Nyssorhyncus darlingi Root (89.8%. This species has considerable epidemiological value, considered the main vector of malaria in Mato Grosso. Many species of mosquitoes are vectors of pathogens that cause disease in humans and domestic animals, transmitting pathogens including viruses (arboviruses, filaria worms (helminths and protozoa. Composição de espécies e distribuição da fauna de mosquitos (Diptera: Culicidae e sua importância para doenças transmitidas por vetores em uma área rural do centro-ocidental - Mato Grosso, Brasil Resumo. Este estudo descreve dados ecológicos de uma área rural do Estado de Mato Grosso e dos insetos da família Culicidae especialmente aqueles enquadrados como vetores potenciais de doenças tropicais. Em 2015, coletamos mosquitos adultos em fragmentos de floresta em localidades de áreas rurais no Mato Grosso região Centro Oeste do Brasil. Foram capturados 18.256 exemplares alados de mosquitos das subfamílias Culicinae e Anophelinae e identificadas 34 espécies pertencentes a 12 g

  12. Tick-borne disease.

    Science.gov (United States)

    Bratton, Robert L; Corey, Ralph

    2005-06-15

    Tick-borne diseases in the United States include Rocky Mountain spotted fever, Lyme disease, ehrlichiosis, tularemia, babesiosis, Colorado tick fever, and relapsing fever. It is important for family physicians to consider these illnesses when patients present with influenza-like symptoms. A petechial rash initially affecting the palms and soles of the feet is associated with Rocky Mountain spotted fever, whereas erythema migrans (annular macule with central clearing) is associated with Lyme disease. Various other rashes or skin lesions accompanied by fever and influenza-like illness also may signal the presence of a tick-borne disease. Early, accurate diagnosis allows treatment that may help prevent significant morbidity and possible mortality. Because 24 to 48 hours of attachment to the host are required for infection to occur, early removal can help prevent disease. Treatment with doxycycline or tetracycline is indicated for Rocky Mountain spotted fever, Lyme disease, ehrlichiosis, and relapsing fever. In patients with clinical findings suggestive of tick-borne disease, treatment should not be delayed for laboratory confirmation. If no symptoms follow exposure to tick bites, empiric treatment is not indicated. The same tick may harbor different infectious pathogens and transmit several with one bite. Advising patients about prevention of tick bites, especially in the summer months, may help prevent exposure to dangerous vector-borne diseases.

  13. Vectors of rickettsiae in Africa.

    Science.gov (United States)

    Bitam, Idir

    2012-12-01

    Vector-borne diseases are caused by parasites, bacteria, or viruses transmitted by the bites of hematophagous arthropods. In Africa, there has been a recent emergence of new diseases and the re-emergence of existing diseases, usually with changes in disease epidemiology (e.g., geographical distribution, prevalence, and pathogenicity). In Africa, rickettsioses are recognized as important emerging vector-borne infections in humans. Rickettsial diseases are transmitted by different types of arthropods, ticks, fleas, lice, and mites. This review will examine the roles of these different arthropod vectors and their geographical distributions. Copyright © 2012 Elsevier GmbH. All rights reserved.

  14. Environmental statistical modelling of mosquito vectors at different geographical scales

    NARCIS (Netherlands)

    Cianci, D.

    2015-01-01

    Vector-borne diseases are infections transmitted by the bite of infected arthropod vectors, such as mosquitoes, ticks, fleas, midges and flies. Vector-borne diseases pose an increasingly wider threat to global public health, both in terms of people affected and their geographical spread. Mosquitoes

  15. Imported Asian swamp eels (Synbranchidae: Monopterus) in North American live food markets: Potential vectors of non-native parasites

    Science.gov (United States)

    Nico, Leo G.; Sharp, Paul; Collins, Timothy M.

    2011-01-01

    Since the 1990s, possibly earlier, large numbers of Asian swamp eels (Synbranchidae: Monopterus spp.), some wild-caught, have been imported live from various countries in Asia and sold in ethnic food markets in cities throughout the USA and parts of Canada. Such markets are the likely introduction pathway of some, perhaps most, of the five known wild populations of Asian swamp eels present in the continental United States. This paper presents results of a pilot study intended to gather baseline data on the occurrence and abundance of internal macroparasites infecting swamp eels imported from Asia to North American retail food markets. These data are important in assessing the potential role that imported swamp eels may play as possible vectors of non-native parasites. Examination of the gastrointestinal tracts and associated tissues of 19 adult-sized swamp eels—identified as M. albus "Clade C"—imported from Vietnam and present in a U.S. retail food market revealed that 18 (95%) contained macroparasites. The 394 individual parasites recovered included a mix of nematodes, acanthocephalans, cestodes, digeneans, and pentastomes. The findings raise concern because of the likelihood that some parasites infecting market swamp eels imported from Asia are themselves Asian taxa, some possibly new to North America. The ecological risk is exacerbated because swamp eels sold in food markets are occasionally retained live by customers and a few reportedly released into the wild. For comparative purposes, M. albus "Clade C" swamp eels from a non-native population in Florida (USA) were also examined and most (84%) were found to be infected with internal macroparasites. The current level of analysis does not allow us to confirm whether these are non-native parasites.

  16. Tick-borne encephalitis.

    Science.gov (United States)

    Dumpis, U; Crook, D; Oksi, J

    1999-04-01

    Tick-borne encephalitis (TBE) is a zoonotic arbovirus infection endemic to Russia and Eastern and Central Europe. Despite being a common and serious life-threatening disease for which a mass vaccination program was implemented in Austria, there is only limited reference to this disease in the English-language literature. TBE is transmitted to humans usually by the bite of a tick (either Ixodes persulcatus or Ixodes ricinus); occasionally, cases occur following consumption of infected unpasteurized milk. Transmission is seasonal and occurs in spring and summer, particularly in rural areas favored by the vector. TBE is a serious cause of acute central nervous system disease, which may result in death or long-term neurological sequelae. Effective vaccines are available in a few countries. The risk for travelers of acquiring TBE is increasing with the recent rise in tourism to areas of endemicity during spring and summer.

  17. Dual symmetry in Born-Infeld theory

    International Nuclear Information System (INIS)

    Khademi, S; Ayoubi, A

    2008-01-01

    Born-Infeld theory is a non-linear formalism which has many applications in string and electromagnetic theories. Although, the existence of magnetic monopoles and dyons are suggested by Born-Infeld theory, but this theory is not invariant under the dual transformations. In this theory electric fields for point charged particles are not singular at origin (r = 0), but magnetic fields and vector potentials are still singular. In this paper we show that the vanishing of dual symmetry is responsible for these singularities. Furthermore, we present the dual symmetric Born-Infeld theory, by a symmetric definition of electromagnetic fields in terms of new scalar and vector potentials, as well as the ordinary ones. All singularities of vector potential and magnetic field are removed as an immediate consequence of this symmetry.

  18. Mosquito-borne viruses in Europe

    Czech Academy of Sciences Publication Activity Database

    Hubálek, Zdeněk

    2008-01-01

    Roč. 103, Suppl. 1 (2008), S29-S43 ISSN 0932-0113. [Vector-borne diseases: impact of climate change on vectors and rodent reservoirs. Berlin, 27.09.2007-28.09.2007] R&D Projects: GA AV ČR IAA600930611 Institutional research plan: CEZ:AV0Z60930519 Keywords : moboviruses * epidemiology Subject RIV: EE - Microbiology, Virology Impact factor: 1.473, year: 2008

  19. Beyond the vector | IDRC - International Development Research ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2011-05-30

    May 30, 2011 ... IDRC's Ecosystems and Human Health Program - Ecohealth - works with ... to find solutions to human health problems rooted in ecosystem conditions. ... Vector-borne diseases are a significant public health concern in Latin ...

  20. Vector analysis

    CERN Document Server

    Newell, Homer E

    2006-01-01

    When employed with skill and understanding, vector analysis can be a practical and powerful tool. This text develops the algebra and calculus of vectors in a manner useful to physicists and engineers. Numerous exercises (with answers) not only provide practice in manipulation but also help establish students' physical and geometric intuition in regard to vectors and vector concepts.Part I, the basic portion of the text, consists of a thorough treatment of vector algebra and the vector calculus. Part II presents the illustrative matter, demonstrating applications to kinematics, mechanics, and e

  1. About vectors

    CERN Document Server

    Hoffmann, Banesh

    1975-01-01

    From his unusual beginning in ""Defining a vector"" to his final comments on ""What then is a vector?"" author Banesh Hoffmann has written a book that is provocative and unconventional. In his emphasis on the unresolved issue of defining a vector, Hoffmann mixes pure and applied mathematics without using calculus. The result is a treatment that can serve as a supplement and corrective to textbooks, as well as collateral reading in all courses that deal with vectors. Major topics include vectors and the parallelogram law; algebraic notation and basic ideas; vector algebra; scalars and scalar p

  2. Integration of a Tick-Borne Encephalitis Virus and Borrelia burgdorferi sensu lato into Mountain Ecosystems, Following a Shift in the Altitudinal Limit of Distribution of Their Vector, Ixodes ricinus (Krkonoše Mountains, Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Danielová, V.; Daniel, M.; Schwarzová, L.; Materna, J.; Rudenko, Natalia; Golovchenko, Maryna; Holubová, J.; Grubhoffer, Libor; Kilian, P.

    2010-01-01

    Roč. 10, č. 3 (2010), s. 223-230 ISSN 1530-3667 Grant - others:GA ČR(CZ) GA310/06/1546 Institutional research plan: CEZ:AV0Z60220518 Keywords : Borrelia burgdorferi genospecies * Climate * Ixodes ricinus tick * Mountain ecosystems * Tick-borne encephalitis virus Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 2.733, year: 2010

  3. Declining Prevalence of Disease Vectors Under Climate Change

    DEFF Research Database (Denmark)

    Escobar, Luis E.; Romero-Alvarez, Daniel; Leon, Renato

    2016-01-01

    More than half of the world population is at risk of vector-borne diseases including dengue fever, chikungunya, zika, yellow fever, leishmaniasis, chagas disease, and malaria, with highest incidences in tropical regions. In Ecuador, vector-borne diseases are present from coastal and Amazonian...

  4. 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

  5. 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

  6. Elementary vectors

    CERN Document Server

    Wolstenholme, E Œ

    1978-01-01

    Elementary Vectors, Third Edition serves as an introductory course in vector analysis and is intended to present the theoretical and application aspects of vectors. The book covers topics that rigorously explain and provide definitions, principles, equations, and methods in vector analysis. Applications of vector methods to simple kinematical and dynamical problems; central forces and orbits; and solutions to geometrical problems are discussed as well. This edition of the text also provides an appendix, intended for students, which the author hopes to bridge the gap between theory and appl

  7. Nanoparticles in the fight against mosquito-borne diseases: bioactivity of Bruguiera cylindrica-synthesized nanoparticles against dengue virus DEN-2 (in vitro) and its mosquito vector Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Murugan, Kadarkarai; Dinesh, Devakumar; Paulpandi, Manickam; Althbyani, Abdulaziz Dakhellah Meqbel; Subramaniam, Jayapal; Madhiyazhagan, Pari; Wang, Lan; Suresh, Udaiyan; Kumar, Palanisamy Mahesh; Mohan, Jagathish; Rajaganesh, Rajapandian; Wei, Hui; Kalimuthu, Kandasamy; Parajulee, Megha N; Mehlhorn, Heinz; Benelli, Giovanni

    2015-12-01

    Mosquitoes are blood-feeding insects serving as the most important vectors for spreading human pathogens and parasites. Dengue is a viral disease mainly vectored through the bite of Aedes mosquitoes. Its transmission has recently increased in urban and semi-urban areas of tropical and subtropical regions worldwide, becoming a major international public health concern. There is no specific treatment for dengue. Its prevention and control solely depend on effective vector control measures. Mangrove plants have been used in Indian traditional medicine for a wide array of purposes. In this research, we proposed a method for biosynthesis of antiviral and mosquitocidal silver nanoparticles (AgNP) using the aqueous extract of Bruguiera cylindrica leaves. AgNP were characterized using a variety of biophysical analyses, including UV-visible spectrophotometry, Fourier-transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Bruguiera cilyndrica aqueous extract and green-synthesized AgNP were tested against the primary dengue vector Aedes aegypti. AgNP were the most effective. LC50 values ranged from 8.93 ppm (larva I) to 30.69 ppm (pupa). In vitro experiments showed that 30 μg/ml of AgNP significantly inhibited the production of dengue viral envelope (E) protein in vero cells and downregulated the expression of dengue viral E gene. Concerning nontarget effects, we observed that the predation efficiency of Carassius auratus against A. aegypti was not affected by exposure at sublethal doses of AgNP. Predation in the control was 71.81 % (larva II) and 50.43 % (larva III), while in an AgNP-treated environment, predation was boosted to 90.25 and 76.81 %, respectively. Overall, this study highlights the concrete potential of green-synthesized AgNP in the fight against dengue virus. Furthermore, B. cylindrica-synthesized AgNP can be employed at low doses to reduce larval and pupal population of A. aegypti, without detrimental

  8. Vector analysis

    CERN Document Server

    Brand, Louis

    2006-01-01

    The use of vectors not only simplifies treatments of differential geometry, mechanics, hydrodynamics, and electrodynamics, but also makes mathematical and physical concepts more tangible and easy to grasp. This text for undergraduates was designed as a short introductory course to give students the tools of vector algebra and calculus, as well as a brief glimpse into these subjects' manifold applications. The applications are developed to the extent that the uses of the potential function, both scalar and vector, are fully illustrated. Moreover, the basic postulates of vector analysis are brou

  9. Declining Prevalence of Disease Vectors Under Climate Change

    Science.gov (United States)

    Escobar, Luis E.; Romero-Alvarez, Daniel; Leon, Renato; Lepe-Lopez, Manuel A.; Craft, Meggan E.; Borbor-Cordova, Mercy J.; Svenning, Jens-Christian

    2016-12-01

    More than half of the world population is at risk of vector-borne diseases including dengue fever, chikungunya, zika, yellow fever, leishmaniasis, chagas disease, and malaria, with highest incidences in tropical regions. In Ecuador, vector-borne diseases are present from coastal and Amazonian regions to the Andes Mountains; however, a detailed characterization of the distribution of their vectors has never been carried out. We estimate the distribution of 14 vectors of the above vector-borne diseases under present-day and future climates. Our results consistently suggest that climate warming is likely threatening some vector species with extinction, locally or completely. These results suggest that climate change could reduce the burden of specific vector species. Other vector species are likely to shift and constrain their geographic range to the highlands in Ecuador potentially affecting novel areas and populations. These forecasts show the need for development of early prevention strategies for vector species currently absent in areas projected as suitable under future climate conditions. Informed interventions could reduce the risk of human exposure to vector species with distributional shifts, in response to current and future climate changes. Based on the mixed effects of future climate on human exposure to disease vectors, we argue that research on vector-borne diseases should be cross-scale and include climatic, demographic, and landscape factors, as well as forces facilitating disease transmission at fine scales.

  10. Vector velocimeter

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention relates to a compact, reliable and low-cost vector velocimeter for example for determining velocities of particles suspended in a gas or fluid flow, or for determining velocity, displacement, rotation, or vibration of a solid surface, the vector velocimeter comprising a laser...

  11. Emerging arthropod-borne diseases of companion animals in Europe.

    Science.gov (United States)

    Beugnet, Frederic; Marié, Jean-Lou

    2009-08-26

    Vector-borne diseases are caused by parasites, bacteria or viruses transmitted by the bite of hematophagous arthropods (mainly ticks and mosquitoes). The past few years have seen the emergence of new diseases, or re-emergence of existing ones, usually with changes in their epidemiology (i.e. geographical distribution, prevalence, and pathogenicity). The frequency of some vector-borne diseases of pets is increasing in Europe, i.e. canine babesiosis, granulocytic anaplasmosis, canine monocytic ehrlichiosis, thrombocytic anaplasmosis, and leishmaniosis. Except for the last, these diseases are transmitted by ticks. Both the distribution and abundance of the three main tick species, Rhipicephalus sanguineus, Dermacentor reticulatus and Ixodes ricinus are changing. The conditions for such changes involve primarily human factors, such as travel with pets, changes in human habitats, social and leisure activities, but climate changes also have a direct impact on arthropod vectors (abundance, geographical distribution, and vectorial capacity). Besides the most known diseases, attention should be kept on tick-borne encephalitis, which seems to be increasing in western Europe, as well as flea-borne diseases like the flea-transmitted rickettsiosis. Here, after consideration of the main reasons for changes in tick vector ecology, an overview of each "emerging" vector-borne diseases of pets is presented.

  12. Cloning vector

    Science.gov (United States)

    Guilfoyle, Richard A.; Smith, Lloyd M.

    1994-01-01

    A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site.

  13. Cloning vector

    Science.gov (United States)

    Guilfoyle, R.A.; Smith, L.M.

    1994-12-27

    A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site. 2 figures.

  14. Equivalent Vectors

    Science.gov (United States)

    Levine, Robert

    2004-01-01

    The cross-product is a mathematical operation that is performed between two 3-dimensional vectors. The result is a vector that is orthogonal or perpendicular to both of them. Learning about this for the first time while taking Calculus-III, the class was taught that if AxB = AxC, it does not necessarily follow that B = C. This seemed baffling. The…

  15. Chikungunya Virus–Vector Interactions

    Directory of Open Access Journals (Sweden)

    Lark L. Coffey

    2014-11-01

    Full Text Available Chikungunya virus (CHIKV is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed.

  16. How effective is integrated vector management against malaria and lymphatic filariasis where the diseases are transmitted by the same vector?

    OpenAIRE

    Stone, C.; Lindsay, S.W.; Chitnis, N.

    2014-01-01

    Background: The opportunity to integrate vector management across multiple vector-borne diseases is particularly plausible for malaria and lymphatic filariasis (LF) control where both diseases are transmitted by the same vector. To date most examples of integrated control targeting these diseases have been unanticipated consequences of malaria vector control, rather than planned strategies that aim to maximize the efficacy and take the complex ecological and biological interactions between th...

  17. Vector geometry

    CERN Document Server

    Robinson, Gilbert de B

    2011-01-01

    This brief undergraduate-level text by a prominent Cambridge-educated mathematician explores the relationship between algebra and geometry. An elementary course in plane geometry is the sole requirement for Gilbert de B. Robinson's text, which is the result of several years of teaching and learning the most effective methods from discussions with students. Topics include lines and planes, determinants and linear equations, matrices, groups and linear transformations, and vectors and vector spaces. Additional subjects range from conics and quadrics to homogeneous coordinates and projective geom

  18. Innovative Born Globals

    DEFF Research Database (Denmark)

    Kraus, Sascha; Brem, Alexander; Muench, Miriam

    2017-01-01

    Internationalization is a hot topic in innovation management, whereby the phenomenon of “Born Globals” is still limited to research in the domains of Entrepreneurship and International Management. As business model design plays a key role for Born Globals, we link these two concepts. For this, we...... propose hypotheses about the influence of efficiency-centered and novelty-entered business model design on international firm performance. To test these hypotheses, we performed a quantitative survey with 252 founders of international companies in Germany, Switzerland and Liechtenstein. Additionally, we...... gained further insights through a case study analysis of 11 Born Globals. The results show that business model design matters to international firm performance and the business model design of Born Globals tends to be more efficiency-centered. Based on a multiple case study, we analyzed business models...

  19. A born dreamer

    Indian Academy of Sciences (India)

    Lawrence

    encouraged me to believe that education was the only way to fulfil one's dreams ... liant student, financial constraints prevented him from pursuing. A born ... higher education. .... to fulfil one's dream despite difficulties, which women face. How-.

  20. VECTOR INTEGRATION

    NARCIS (Netherlands)

    Thomas, E. G. F.

    2012-01-01

    This paper deals with the theory of integration of scalar functions with respect to a measure with values in a, not necessarily locally convex, topological vector space. It focuses on the extension of such integrals from bounded measurable functions to the class of integrable functions, proving

  1. Architecture and Vector Control

    DEFF Research Database (Denmark)

    von Seidlein, Lorenz; Knols, Bart GJ; Kirby, Matthew

    2012-01-01

    , closing of eaves and insecticide treated bednets. All of these interventions have an effect on the indoor climate. Temperature, humidity and airflow are critical for a comfortable climate. Air-conditioning and fans allow us to control indoor climate, but many people in Africa and Asia who carry the brunt...... of vector-borne diseases have no access to electricity. Many houses in the hot, humid regions of Asia have adapted to the environment, they are built of porous materials and are elevated on stilts features which allow a comfortable climate even in the presence of bednets and screens. In contrast, many...... buildings in Africa and Asia in respect to their indoor climate characteristics and finally, show how state-of-the-art 3D modelling can predict climate characteristics and help to optimize buildings....

  2. An introduction to vectors, vector operators and vector analysis

    CERN Document Server

    Joag, Pramod S

    2016-01-01

    Ideal for undergraduate and graduate students of science and engineering, this book covers fundamental concepts of vectors and their applications in a single volume. The first unit deals with basic formulation, both conceptual and theoretical. It discusses applications of algebraic operations, Levi-Civita notation, and curvilinear coordinate systems like spherical polar and parabolic systems and structures, and analytical geometry of curves and surfaces. The second unit delves into the algebra of operators and their types and also explains the equivalence between the algebra of vector operators and the algebra of matrices. Formulation of eigen vectors and eigen values of a linear vector operator are elaborated using vector algebra. The third unit deals with vector analysis, discussing vector valued functions of a scalar variable and functions of vector argument (both scalar valued and vector valued), thus covering both the scalar vector fields and vector integration.

  3. A Nod to disease vectors: mitigation of pathogen sensing by arthropod saliva

    Czech Academy of Sciences Publication Activity Database

    Sakhon, O. S.; Severo, M. S.; Kotsyfakis, Michalis; Pedra, J. H. F.

    2013-01-01

    Roč. 4, OCT 2013 (2013), a308 ISSN 1664-302X Institutional support: RVO:60077344 Keywords : nod-like receptors * inflammasome * vector-borne pathogens * vector-borne diseases * arthropod saliva * salivary proteins Subject RIV: EC - Immunology Impact factor: 3.941, year: 2013

  4. [Tick borne diseases].

    Science.gov (United States)

    Holzer, B R

    2005-11-01

    It is known for many years that tick-borne diseases have worldwide a high economical impact on farming industry and veterinary medicine. But only in the last twenty years the importance of such diseases were notified in human medicine by the medical community and the public with emerging of the tick borne encephalitis virus and the description of Borrelia burgdorferi. It is often forgotten that many other infectious agents as bacteria, virus, Rickettsia or protozoa can be transmitted by ticks. Such diseases are rarely diagnosed in Europe either they are overlooked and misdiagnosed or they are connected with special professional activities. The development of new regions for tourism with different out door activities (adventure trips, trekking, hunting) leads to an exposure to different tick borne diseases, which are often misdiagnosed.

  5. Population Health Vulnerabilities to Vector-borne Diseases ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Damming, irrigation and other forms of water management are also creating new habitats ... adaptation, particularly to improve the resilience of vulnerable populations. ... Linking research to urban planning at the ICLEI World Congress 2018.

  6. Taking the Bite Out of Vector-Borne Diseases

    Science.gov (United States)

    ... with implications for how diseases spread. Disease Control Elephantiasis caused by parasitic worms (top) affects more than ... inflammatory responses that lead to river blindness and elephantiasis. In an ironic twist, researchers are actually using ...

  7. Venezuela and its rising vector-borne neglected diseases

    OpenAIRE

    Hotez, Peter J.; Bas??ez, Mar?a-Gloria; Acosta-Serrano, Alvaro; Grillet, Maria Eugenia

    2017-01-01

    Poverty remains the overriding social determinant for the neglected tropical diseases (NTDs), but over the last several decades, we have also seen how political destabilization or even outright conflict can hasten economic declines and promote a substantial uptick in NTD incidence and prevalence [1]. Recent examples include the emergence of Ebola virus infection in West Africa [2], visceral leishmaniasis and other NTDs in East Africa [3, 4], and cutaneous leishmaniasis in the Middle East and ...

  8. The quest for a non-vector psyllid: Natural variation in acquisition and transmission of the huanglongbing pathogen 'Candidatus Liberibacter asiaticus' by Asian citrus psyllid isofemale lines

    Science.gov (United States)

    Genetic variability in insect vectors is valuable to study vector competence determinants and to select non-vector populations that may help reduce the spread of vector-borne pathogens. We collected and tested vector competency of 15 isofemale lines of Asian citrus psyllid (ACP) Diaphorina citri, v...

  9. Occurrence of antibodies to Anaplasma phagocytophilum in patients with suspected tick-borne encephalitis

    Directory of Open Access Journals (Sweden)

    Zuzana Kalinová

    2015-09-01

    None of the examined patients with suspected TBE had the disease confirmed. Hoever, as shown by the results, the relative risk of occurrence of anaplasmosis is higher in people examined for some another vector-borne disease (in this case TBE. Therefore, the performance of screening examinations in patients suspected of having any tick-borne disease is very important.

  10. Two-host, two-vector basic reproduction ratio (R(0 for bluetongue.

    Directory of Open Access Journals (Sweden)

    Joanne Turner

    Full Text Available Mathematical formulations for the basic reproduction ratio (R(0 exist for several vector-borne diseases. Generally, these are based on models of one-host, one-vector systems or two-host, one-vector systems. For many vector borne diseases, however, two or more vector species often co-occur and, therefore, there is a need for more complex formulations. Here we derive a two-host, two-vector formulation for the R(0 of bluetongue, a vector-borne infection of ruminants that can have serious economic consequences; since 1998 for example, it has led to the deaths of well over 1 million sheep in Europe alone. We illustrate our results by considering the situation in South Africa, where there are two major hosts (sheep, cattle and two vector species with differing ecologies and competencies as vectors, for which good data exist. We investigate the effects on R(0 of differences in vector abundance, vector competence and vector host preference between vector species. Our results indicate that R(0 can be underestimated if we assume that there is only one vector transmitting the infection (when there are in fact two or more and/or vector host preferences are overlooked (unless the preferred host is less beneficial or more abundant. The two-host, one-vector formula provides a good approximation when the level of cross-infection between vector species is very small. As this approaches the level of intraspecies infection, a combination of the two-host, one-vector R(0 for each vector species becomes a better estimate. Otherwise, particularly when the level of cross-infection is high, the two-host, two-vector formula is required for accurate estimation of R(0. Our results are equally relevant to Europe, where at least two vector species, which co-occur in parts of the south, have been implicated in the recent epizootic of bluetongue.

  11. Tick-Borne Encephalitis (TBE)

    Science.gov (United States)

    ... virus, Siberian tick-borne encephalitis virus, and Far eastern Tick-borne encephalitis virus (formerly known as Russian ... viruses are closely related to TBEV and Far-eastern TBE, and include Omsk hemorrhagic fever virus in ...

  12. Where was Joseph Babinski born?

    Directory of Open Access Journals (Sweden)

    H A G Teive

    2011-01-01

    Full Text Available There is controversy in the neurological literature about where Joseph Babinski was born, including a myth propounded by various important authors that he was born in Lima, Peru. However, according to the most consistent biographical data, he was in fact born in Paris, France, and became a medical celebrity there and in Poland as well as around the world.

  13. Generalized Born-Infeld actions and projective cubic curves

    Energy Technology Data Exchange (ETDEWEB)

    Ferrara, S. [Department of Physics, CERN Theory Division, CH - 1211 Geneva 23 (Switzerland); INFN - Laboratori Nazionali di Frascati, Via Enrico Fermi 40, I-00044, Frascati (Italy); Porrati, M. [CCPP, Department of Physics, NYU, 4 Washington Pl., New York, NY, 10003 (United States); Sagnotti, A. [Department of Physics, CERN Theory Division, CH - 1211 Geneva 23 (Switzerland); Stora, R. [Department of Physics, CERN Theory Division, CH - 1211 Geneva 23 (Switzerland); Laboratoire d' Annecy-le-Vieux de Physique Theorique (LAPTH), F-74941, Annecy-le-Vieux, Cedex (France); Yeranyan, A. [INFN - Laboratori Nazionali di Frascati, Via Enrico Fermi 40, I-00044, Frascati (Italy); Centro Studi e Ricerche Enrico Fermi, Via Panisperna 89A, 00184, Roma (Italy)

    2015-04-01

    We investigate U(1){sup n} supersymmetric Born-Infeld Lagrangians with a second non-linearly realized supersymmetry. The resulting non-linear structure is more complex than the square root present in the standard Born-Infeld action, and nonetheless the quadratic constraints determining these models can be solved exactly in all cases containing three vector multiplets. The corresponding models are classified by cubic holomorphic prepotentials. Their symmetry structures are associated to projective cubic varieties. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Transgenesis and paratransgenesis to control insect-borne diseases: Current status and future challenges

    Science.gov (United States)

    Coutinho-Abreu, Iliano V.; Zhu, Kun Yan; Ramalho-Ortigao, Marcelo

    2009-01-01

    Insect-borne diseases cause significant human morbidity and mortality. Current control and preventive methods against vector-borne diseases rely mainly on insecticides. The emergence of insecticide resistance in many disease vectors highlights the necessity to develop new strategies to control these insects. Vector transgenesis and paratransgenesis are novel strategies that aim at reducing insect vectorial capacity, or seek to eliminate transmission of pathogens such as Plasmodium sp., Trypanosoma sp., and Dengue virus currently being developed. Vector transgenesis relies on direct genetic manipulation of disease vectors making them incapable of functioning as vectors of a given pathogen. Paratransgenesis focuses on utilizing genetically modified insect symbionts to express molecules within the vector that are deleterious to pathogens they transmit. Despite the many successes achieved in developing such techniques in the last several years, many significant barriers remain and need to be overcome prior to any of these approaches become a reality. Here, we highlight the current status of these strategies, pointing out advantages and constraints, and also explore issues that need to be resolved before the establishment of transgenesis and paratransgenesis as tools to prevent vector-borne diseases. PMID:19819346

  15. Raster images vectorization system

    OpenAIRE

    Genytė, Jurgita

    2006-01-01

    The problem of raster images vectorization was analyzed and researched in this work. Existing vectorization systems are quite expensive, the results are inaccurate, and the manual vectorization of a large number of drafts is impossible. That‘s why our goal was to design and develop a new raster images vectorization system using our suggested automatic vectorization algorithm and the way to record results in a new universal vectorial file format. The work consists of these main parts: analysis...

  16. Kochen-Specker vectors

    International Nuclear Information System (INIS)

    Pavicic, Mladen; Merlet, Jean-Pierre; McKay, Brendan; Megill, Norman D

    2005-01-01

    We give a constructive and exhaustive definition of Kochen-Specker (KS) vectors in a Hilbert space of any dimension as well as of all the remaining vectors of the space. KS vectors are elements of any set of orthonormal states, i.e., vectors in an n-dimensional Hilbert space, H n , n≥3, to which it is impossible to assign 1s and 0s in such a way that no two mutually orthogonal vectors from the set are both assigned 1 and that not all mutually orthogonal vectors are assigned 0. Our constructive definition of such KS vectors is based on algorithms that generate MMP diagrams corresponding to blocks of orthogonal vectors in R n , on algorithms that single out those diagrams on which algebraic (0)-(1) states cannot be defined, and on algorithms that solve nonlinear equations describing the orthogonalities of the vectors by means of statistically polynomially complex interval analysis and self-teaching programs. The algorithms are limited neither by the number of dimensions nor by the number of vectors. To demonstrate the power of the algorithms, all four-dimensional KS vector systems containing up to 24 vectors were generated and described, all three-dimensional vector systems containing up to 30 vectors were scanned, and several general properties of KS vectors were found

  17. Some Models for Epidemics of Vector-Transmitted Diseases

    OpenAIRE

    Brauer, Fred; Castillo-Chavez, Carlos; Mubayi, Anuj; Towers, Sherry

    2016-01-01

    Vector-transmitted diseases such as dengue fever and chikungunya have been spreading rapidly in many parts of the world. The Zika virus has been known since 1947 and invaded South America in 2013. It can be transmitted not only by (mosquito) vectors but also directly through sexual contact. Zika has developed into a serious global health problem because, while most cases are asymptomatic or very light, babies born to Zika - infected mothers may develop microcephaly and other very serious birt...

  18. Vector regression introduced

    Directory of Open Access Journals (Sweden)

    Mok Tik

    2014-06-01

    Full Text Available This study formulates regression of vector data that will enable statistical analysis of various geodetic phenomena such as, polar motion, ocean currents, typhoon/hurricane tracking, crustal deformations, and precursory earthquake signals. The observed vector variable of an event (dependent vector variable is expressed as a function of a number of hypothesized phenomena realized also as vector variables (independent vector variables and/or scalar variables that are likely to impact the dependent vector variable. The proposed representation has the unique property of solving the coefficients of independent vector variables (explanatory variables also as vectors, hence it supersedes multivariate multiple regression models, in which the unknown coefficients are scalar quantities. For the solution, complex numbers are used to rep- resent vector information, and the method of least squares is deployed to estimate the vector model parameters after transforming the complex vector regression model into a real vector regression model through isomorphism. Various operational statistics for testing the predictive significance of the estimated vector parameter coefficients are also derived. A simple numerical example demonstrates the use of the proposed vector regression analysis in modeling typhoon paths.

  19. Early Recollections of First-Borns.

    Science.gov (United States)

    Fakouri, M. Ebrahim; Hafner, James L.

    1984-01-01

    Compared the early recollections of 50 first-borns and 98 later-borns. The first-borns mentioned significantly more nonfamily members, illness/injury, hospital/doctor's office. Later-borns mentioned significantly more siblings than did first-borns. Findings were discussed in the context of Adler's personality theory. (JAC)

  20. Molecular entomology: analyzing tiny molecules to answer big questions about disease vectors and their biology

    Science.gov (United States)

    The entomologists at the Arthropod-Borne Animal Diseases Research Unit at USDA-Agricultural Research Service are tasked with protecting the nation’s livestock from domestic, foreign and emerging vector-borne diseases. To accomplish this task, a vast array of molecular techniques are being used in pr...

  1. Born : vastutustundlikud tulevikus edukad / Kerstin Born ; interv. Kristo Kiviorg

    Index Scriptorium Estoniae

    Born, Kerstin

    2007-01-01

    Vastutustundliku ettevõtluse Euroopa organisatsiooni CSR Europe'i juht Kerstin Born vastab küsimustele ettevõtete vastutustundlikkuse kohta ühiskonnas. Vt. samas: Käivitus vastutustundliku ettevõtluse indeks

  2. VectorBase

    Data.gov (United States)

    U.S. Department of Health & Human Services — VectorBase is a Bioinformatics Resource Center for invertebrate vectors. It is one of four Bioinformatics Resource Centers funded by NIAID to provide web-based...

  3. Generalization of concurrence vectors

    International Nuclear Information System (INIS)

    Yu Changshui; Song Heshan

    2004-01-01

    In this Letter, based on the generalization of concurrence vectors for bipartite pure state with respect to employing tensor product of generators of the corresponding rotation groups, we generalize concurrence vectors to the case of mixed states; a new criterion of separability of multipartite pure states is given out, for which we define a concurrence vector; we generalize the vector to the case of multipartite mixed state and give out a good measure of free entanglement

  4. Vector Network Coding

    OpenAIRE

    Ebrahimi, Javad; Fragouli, Christina

    2010-01-01

    We develop new algebraic algorithms for scalar and vector network coding. In vector network coding, the source multicasts information by transmitting vectors of length L, while intermediate nodes process and combine their incoming packets by multiplying them with L X L coding matrices that play a similar role as coding coefficients in scalar coding. Our algorithms for scalar network jointly optimize the employed field size while selecting the coding coefficients. Similarly, for vector co...

  5. Vector Network Coding Algorithms

    OpenAIRE

    Ebrahimi, Javad; Fragouli, Christina

    2010-01-01

    We develop new algebraic algorithms for scalar and vector network coding. In vector network coding, the source multicasts information by transmitting vectors of length L, while intermediate nodes process and combine their incoming packets by multiplying them with L x L coding matrices that play a similar role as coding c in scalar coding. Our algorithms for scalar network jointly optimize the employed field size while selecting the coding coefficients. Similarly, for vector coding, our algori...

  6. Can Horton hear the whos? The importance of scale in mosquito-borne disease.

    Science.gov (United States)

    Lord, C C; Alto, B W; Anderson, S L; Connelly, C R; Day, J F; Richards, S L; Smartt, C T; Tabachnick, W J

    2014-03-01

    The epidemiology of vector-borne pathogens is determined by mechanisms and interactions at different scales of biological organization, from individual-level cellular processes to community interactions between species and with the environment. Most research, however, focuses on one scale or level with little integration between scales or levels within scales. Understanding the interactions between levels and how they influence our perception of vector-borne pathogens is critical. Here two examples of biological scales (pathogen transmission and mosquito mortality) are presented to illustrate some of the issues of scale and to explore how processes on different levels may interact to influence mosquito-borne pathogen transmission cycles. Individual variation in survival, vector competence, and other traits affect population abundance, transmission potential, and community structure. Community structure affects interactions between individuals such as competition and predation, and thus influences the individual-level dynamics and transmission potential. Modeling is a valuable tool to assess interactions between scales and how processes at different levels can affect transmission dynamics. We expand an existing model to illustrate the types of studies needed, showing that individual-level variation in viral dose acquired or needed for infection can influence the number of infectious vectors. It is critical that interactions within and among biological scales and levels of biological organization are understood for greater understanding of pathogen transmission with the ultimate goal of improving control of vector-borne pathogens.

  7. Convexity and Marginal Vectors

    NARCIS (Netherlands)

    van Velzen, S.; Hamers, H.J.M.; Norde, H.W.

    2002-01-01

    In this paper we construct sets of marginal vectors of a TU game with the property that if the marginal vectors from these sets are core elements, then the game is convex.This approach leads to new upperbounds on the number of marginal vectors needed to characterize convexity.An other result is that

  8. Custodial vector model

    DEFF Research Database (Denmark)

    Becciolini, Diego; Franzosi, Diogo Buarque; Foadi, Roshan

    2015-01-01

    We analyze the Large Hadron Collider (LHC) phenomenology of heavy vector resonances with a $SU(2)_L\\times SU(2)_R$ spectral global symmetry. This symmetry partially protects the electroweak S-parameter from large contributions of the vector resonances. The resulting custodial vector model spectrum...

  9. Rift Valley fever potential mosquito vectors and their infection status ...

    African Journals Online (AJOL)

    Background: Rift Valley fever (RVF) is a mosquito-borne viral zoonotic disease. Rift Valley fever virus (RVFV) has been isolated from more than 40 species of mosquitoes from eight genera. This study was conducted to determine the abundance of potential mosquito vectors and their RVFV infection status in Ngorongoro ...

  10. Born-Infeld Nonlinear Electrodynamics

    International Nuclear Information System (INIS)

    Bialynicki-Birula, I.

    1999-01-01

    This is only a summary of a lecture delivered at the Infeld Centennial Meeting. In the lecture the history of the Born-Infeld nonlinear electrodynamics was presented and some general features of the theory were discussed. (author)

  11. Simulating spread of Bluetongue Virus by flying vectors between hosts on pasture

    DEFF Research Database (Denmark)

    Græsbøll, Kaare; Bødker, Rene; Enøe, Claes

    2012-01-01

    Bluetongue is a disease of ruminants which reached Denmark in 2007. We present a process-based stochastic simulation model of vector-borne diseases, where host animals are not confined to a central geographic farm coordinate, but can be distributed onto pasture areas. Furthermore vectors fly freely...

  12. Rotations with Rodrigues' vector

    International Nuclear Information System (INIS)

    Pina, E

    2011-01-01

    The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears to be a fundamental matrix that is used to express the components of the angular velocity, the rotation matrix and the angular momentum vector. The Hamiltonian formalism of rotational dynamics in terms of this vector uses the same matrix. The quantization of the rotational dynamics is performed with simple rules if one uses Rodrigues' vector and similar formal expressions for the quantum operators that mimic the Hamiltonian classical dynamics.

  13. Tick-borne infections in human and animal population worldwide

    Directory of Open Access Journals (Sweden)

    José Brites-Neto

    2015-03-01

    Full Text Available The abundance and activity of ectoparasites and its hosts are affected by various abiotic factors, such as climate and other organisms (predators, pathogens and competitors presenting thus multiples forms of association (obligate to facultative, permanent to intermittent and superficial to subcutaneous developed during long co-evolving processes. Ticks are ectoparasites widespread globally and its eco epidemiology are closely related to the environmental conditions. They are obligatory hematophagous ectoparasites and responsible as vectors or reservoirs at the transmission of pathogenic fungi, protozoa, viruses, rickettsia and others bacteria during their feeding process on the hosts. Ticks constitute the second vector group that transmit the major number of pathogens to humans and play a role primary for animals in the process of diseases transmission. Many studies on bioecology of ticks, considering the information related to their population dynamics, to the host and the environment, comes possible the application and efficiency of tick control measures in the prevention programs of vector-borne diseases. In this review were considered some taxonomic, morphological, epidemiological and clinical fundamental aspects related to the tick-borne infections that affect human and animal populations.

  14. Impact of climate trends on tick-borne pathogen transmission

    Directory of Open Access Journals (Sweden)

    Agustin eEstrada-Pena

    2012-03-01

    Full Text Available Recent advances in climate research together with a better understanding of tick-pathogen interactions, the distribution of ticks and the diagnosis of tick-borne pathogens raise questions about the impact of environmental factors on tick abundance and spread and the prevalence and transmission of tick-borne pathogens. While undoubtedly climate plays a role in the changes in distribution and seasonal abundance of ticks, it is always difficult to disentangle factors impacting on the abundance of tick hosts from those exerted by human habits. All together, climate, host abundance and social factors may explain the upsurge of epidemics transmitted by ticks to humans. Herein we focused on tick-borne pathogens that affect humans with pandemic potential. Borrelia burgdorferi s.l. (Lyme disease, Anaplasma phagocytophilum (human granulocytic anaplasmosis and tick-borne encephalitis virus (tick-borne encephalitis are transmitted by Ixodes spp. Crimean-Congo hemorrhagic fever virus (Crimean-Congo hemorrhagic fever is transmitted by Hyalomma spp. In this review, we discussed how vector tick species occupy the habitat as a function of different climatic factors, and how these factors impact on tick survival and seasonality. How molecular events at the tick-pathogen interface impact on pathogen transmission is also discussed. Results from statistically and biologically derived models are compared to show that while statistical models are able to outline basic information about tick distributions, biologically derived models are necessary to evaluate pathogen transmission rates and understand the effect of climatic variables and host abundance patterns on pathogen transmission. The results of these studies could be used to build early alert systems able to identify the main factors driving the subtle changes in tick distribution and seasonality and the prevalence of tick-borne pathogens.

  15. Supergravity inspired vector curvaton

    International Nuclear Information System (INIS)

    Dimopoulos, Konstantinos

    2007-01-01

    It is investigated whether a massive Abelian vector field, whose gauge kinetic function is growing during inflation, can be responsible for the generation of the curvature perturbation in the Universe. Particle production is studied and it is shown that the vector field can obtain a scale-invariant superhorizon spectrum of perturbations with a reasonable choice of kinetic function. After inflation the vector field begins coherent oscillations, during which it corresponds to pressureless isotropic matter. When the vector field dominates the Universe, its perturbations give rise to the observed curvature perturbation following the curvaton scenario. It is found that this is possible if, after the end of inflation, the mass of the vector field increases at a phase transition at temperature of order 1 TeV or lower. Inhomogeneous reheating, whereby the vector field modulates the decay rate of the inflaton, is also studied

  16. Custodial vector model

    Science.gov (United States)

    Becciolini, Diego; Franzosi, Diogo Buarque; Foadi, Roshan; Frandsen, Mads T.; Hapola, Tuomas; Sannino, Francesco

    2015-07-01

    We analyze the Large Hadron Collider (LHC) phenomenology of heavy vector resonances with a S U (2 )L×S U (2 )R spectral global symmetry. This symmetry partially protects the electroweak S parameter from large contributions of the vector resonances. The resulting custodial vector model spectrum and interactions with the standard model fields lead to distinct signatures at the LHC in the diboson, dilepton, and associated Higgs channels.

  17. Vector Differential Calculus

    OpenAIRE

    HITZER, Eckhard MS

    2002-01-01

    This paper treats the fundamentals of the vector differential calculus part of universal geometric calculus. Geometric calculus simplifies and unifies the structure and notation of mathematics for all of science and engineering, and for technological applications. In order to make the treatment self-contained, I first compile all important geometric algebra relationships,which are necesssary for vector differential calculus. Then differentiation by vectors is introduced and a host of major ve...

  18. Implicit Real Vector Automata

    Directory of Open Access Journals (Sweden)

    Jean-François Degbomont

    2010-10-01

    Full Text Available This paper addresses the symbolic representation of non-convex real polyhedra, i.e., sets of real vectors satisfying arbitrary Boolean combinations of linear constraints. We develop an original data structure for representing such sets, based on an implicit and concise encoding of a known structure, the Real Vector Automaton. The resulting formalism provides a canonical representation of polyhedra, is closed under Boolean operators, and admits an efficient decision procedure for testing the membership of a vector.

  19. Viral Interference and Persistence in Mosquito-Borne Flaviviruses

    Directory of Open Access Journals (Sweden)

    Juan Santiago Salas-Benito

    2015-01-01

    Full Text Available Mosquito-borne flaviviruses are important pathogens for humans, and the detection of two or more flaviviruses cocirculating in the same geographic area has often been reported. However, the epidemiological impact remains to be determined. Mosquito-borne flaviviruses are primarily transmitted through Aedes and Culex mosquitoes; these viruses establish a life-long or persistent infection without apparent pathological effects. This establishment requires a balance between virus replication and the antiviral host response. Viral interference is a phenomenon whereby one virus inhibits the replication of other viruses, and this condition is frequently associated with persistent infections. Viral interference and persistent infection are determined by several factors, such as defective interfering particles, competition for cellular factors required for translation/replication, and the host antiviral response. The interaction between two flaviviruses typically results in viral interference, indicating that these viruses share common features during the replicative cycle in the vector. The potential mechanisms involved in these processes are reviewed here.

  20. Massive Born--Infeld and Other Dual Pairs

    CERN Document Server

    Ferrara, S

    2015-01-01

    We consider massive dual pairs of p-forms and (D-p-1)-forms described by non-linear Lagrangians, where non-linear curvature terms in one theory translate into non-linear mass-like terms in the dual theory. In particular, for D=2p and p even the two non-linear structures coincide when the non-linear massless theory is self-dual. This state of affairs finds a natural realization in the four-dimensional massive N=1 supersymmetric Born-Infeld action, which describes either a massive vector multiplet or a massive linear (tensor) multiplet with a Born-Infeld mass-like term. These systems should play a role for the massive gravitino multiplet obtained from a partial super-Higgs in N=2 Supergravity.

  1. Vectorized Monte Carlo

    International Nuclear Information System (INIS)

    Brown, F.B.

    1981-01-01

    Examination of the global algorithms and local kernels of conventional general-purpose Monte Carlo codes shows that multigroup Monte Carlo methods have sufficient structure to permit efficient vectorization. A structured multigroup Monte Carlo algorithm for vector computers is developed in which many particle events are treated at once on a cell-by-cell basis. Vectorization of kernels for tracking and variance reduction is described, and a new method for discrete sampling is developed to facilitate the vectorization of collision analysis. To demonstrate the potential of the new method, a vectorized Monte Carlo code for multigroup radiation transport analysis was developed. This code incorporates many features of conventional general-purpose production codes, including general geometry, splitting and Russian roulette, survival biasing, variance estimation via batching, a number of cutoffs, and generalized tallies of collision, tracklength, and surface crossing estimators with response functions. Predictions of vectorized performance characteristics for the CYBER-205 were made using emulated coding and a dynamic model of vector instruction timing. Computation rates were examined for a variety of test problems to determine sensitivities to batch size and vector lengths. Significant speedups are predicted for even a few hundred particles per batch, and asymptotic speedups by about 40 over equivalent Amdahl 470V/8 scalar codes arepredicted for a few thousand particles per batch. The principal conclusion is that vectorization of a general-purpose multigroup Monte Carlo code is well worth the significant effort required for stylized coding and major algorithmic changes

  2. Vectors and their applications

    CERN Document Server

    Pettofrezzo, Anthony J

    2005-01-01

    Geared toward undergraduate students, this text illustrates the use of vectors as a mathematical tool in plane synthetic geometry, plane and spherical trigonometry, and analytic geometry of two- and three-dimensional space. Its rigorous development includes a complete treatment of the algebra of vectors in the first two chapters.Among the text's outstanding features are numbered definitions and theorems in the development of vector algebra, which appear in italics for easy reference. Most of the theorems include proofs, and coordinate position vectors receive an in-depth treatment. Key concept

  3. Symbolic computer vector analysis

    Science.gov (United States)

    Stoutemyer, D. R.

    1977-01-01

    A MACSYMA program is described which performs symbolic vector algebra and vector calculus. The program can combine and simplify symbolic expressions including dot products and cross products, together with the gradient, divergence, curl, and Laplacian operators. The distribution of these operators over sums or products is under user control, as are various other expansions, including expansion into components in any specific orthogonal coordinate system. There is also a capability for deriving the scalar or vector potential of a vector field. Examples include derivation of the partial differential equations describing fluid flow and magnetohydrodynamics, for 12 different classic orthogonal curvilinear coordinate systems.

  4. An Overview of Animal Models for Arthropod-Borne Viruses.

    Science.gov (United States)

    Reynolds, Erin S; Hart, Charles E; Hermance, Meghan E; Brining, Douglas L; Thangamani, Saravanan

    2017-06-01

    Arthropod-borne viruses (arboviruses) have continued to emerge in recent years, posing a significant health threat to millions of people worldwide. The majority of arboviruses that are pathogenic to humans are transmitted by mosquitoes and ticks, but other types of arthropod vectors can also be involved in the transmission of these viruses. To alleviate the health burdens associated with arbovirus infections, it is necessary to focus today's research on disease control and therapeutic strategies. Animal models for arboviruses are valuable experimental tools that can shed light on the pathophysiology of infection and will enable the evaluation of future treatments and vaccine candidates. Ideally an animal model will closely mimic the disease manifestations observed in humans. In this review, we outline the currently available animal models for several viruses vectored by mosquitoes, ticks, and midges, for which there are no standardly available vaccines or therapeutics.

  5. Black hole superradiance signatures of ultralight vectors

    Science.gov (United States)

    Baryakhtar, Masha; Lasenby, Robert; Teo, Mae

    2017-08-01

    The process of superradiance can extract angular momentum and energy from astrophysical black holes (BHs) to populate gravitationally bound states with an exponentially large number of light bosons. We analytically calculate superradiant growth rates for vectors around rotating BHs in the regime where the vector Compton wavelength is much larger than the BH size. Spin-1 bound states have superradiance times as short as a second around stellar BHs, growing up to a thousand times faster than their spin-0 counterparts. The fast rates allow us to use measurements of rapidly spinning BHs in x-ray binaries to exclude a wide range of masses for weakly coupled spin-1 particles, 5 ×10-14-2 ×10-11 eV ; lighter masses in the range 6 ×10-20-2 ×10-17 eV start to be constrained by supermassive BH spin measurements at a lower level of confidence. We also explore routes to detection of new vector particles possible with the advent of gravitational wave (GW) astronomy. The LIGO-Virgo Collaboration could discover hints of a new light vector particle in statistical analyses of masses and spins of merging BHs. Vector annihilations source continuous monochromatic gravitational radiation which could be observed by current GW observatories. At design sensitivity, Advanced LIGO may measure up to thousands of annihilation signals from within the Milky Way, while hundreds of BHs born in binary mergers across the observable Universe may superradiate vector bound states and become new beacons of monochromatic gravitational waves.

  6. Vector-Vector Scattering on the Lattice

    Science.gov (United States)

    Romero-López, Fernando; Urbach, Carsten; Rusetsky, Akaki

    2018-03-01

    In this work we present an extension of the LüScher formalism to include the interaction of particles with spin, focusing on the scattering of two vector particles. The derived formalism will be applied to Scalar QED in the Higgs Phase, where the U(1) gauge boson acquires mass.

  7. Selection vector filter framework

    Science.gov (United States)

    Lukac, Rastislav; Plataniotis, Konstantinos N.; Smolka, Bogdan; Venetsanopoulos, Anastasios N.

    2003-10-01

    We provide a unified framework of nonlinear vector techniques outputting the lowest ranked vector. The proposed framework constitutes a generalized filter class for multichannel signal processing. A new class of nonlinear selection filters are based on the robust order-statistic theory and the minimization of the weighted distance function to other input samples. The proposed method can be designed to perform a variety of filtering operations including previously developed filtering techniques such as vector median, basic vector directional filter, directional distance filter, weighted vector median filters and weighted directional filters. A wide range of filtering operations is guaranteed by the filter structure with two independent weight vectors for angular and distance domains of the vector space. In order to adapt the filter parameters to varying signal and noise statistics, we provide also the generalized optimization algorithms taking the advantage of the weighted median filters and the relationship between standard median filter and vector median filter. Thus, we can deal with both statistical and deterministic aspects of the filter design process. It will be shown that the proposed method holds the required properties such as the capability of modelling the underlying system in the application at hand, the robustness with respect to errors in the model of underlying system, the availability of the training procedure and finally, the simplicity of filter representation, analysis, design and implementation. Simulation studies also indicate that the new filters are computationally attractive and have excellent performance in environments corrupted by bit errors and impulsive noise.

  8. Brane vector phenomenology

    International Nuclear Information System (INIS)

    Clark, T.E.; Love, S.T.; Nitta, Muneto; Veldhuis, T. ter; Xiong, C.

    2009-01-01

    Local oscillations of the brane world are manifested as massive vector fields. Their coupling to the Standard Model can be obtained using the method of nonlinear realizations of the spontaneously broken higher-dimensional space-time symmetries, and to an extent, are model independent. Phenomenological limits on these vector field parameters are obtained using LEP collider data and dark matter constraints

  9. Complex Polynomial Vector Fields

    DEFF Research Database (Denmark)

    The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions...... or meromorphic (allowing poles as singularities) functions. There already exists a well-developed theory for iterative holomorphic dynamical systems, and successful relations found between iteration theory and flows of vector fields have been one of the main motivations for the recent interest in holomorphic...... vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...

  10. Complex Polynomial Vector Fields

    DEFF Research Database (Denmark)

    Dias, Kealey

    vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...... of parameter spaces into structurally stable domains, and a description of the bifurcations. For this reason, the talk will focus on these questions for complex polynomial vector fields.......The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions...

  11. Fractal vector optical fields.

    Science.gov (United States)

    Pan, Yue; Gao, Xu-Zhen; Cai, Meng-Qiang; Zhang, Guan-Lin; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

    2016-07-15

    We introduce the concept of a fractal, which provides an alternative approach for flexibly engineering the optical fields and their focal fields. We propose, design, and create a new family of optical fields-fractal vector optical fields, which build a bridge between the fractal and vector optical fields. The fractal vector optical fields have polarization states exhibiting fractal geometry, and may also involve the phase and/or amplitude simultaneously. The results reveal that the focal fields exhibit self-similarity, and the hierarchy of the fractal has the "weeding" role. The fractal can be used to engineer the focal field.

  12. Bacterial food-borne zoonoses.

    Science.gov (United States)

    Thorns, C J

    2000-04-01

    In many countries of the world, bacterial food-borne zoonotic infections are the most common cause of human intestinal disease. Salmonella and Campylobacter account for over 90% of all reported cases of bacteria-related food poisoning world-wide. Poultry and poultry products have been incriminated in the majority of traceable food-borne illnesses caused by these bacteria, although all domestic livestock are reservoirs of infection. In contrast to the enzootic nature of most Salmonella and Campylobacter infections, Salmonella Enteritidis caused a pandemic in both poultry and humans during the latter half of the 20th Century. Salmonella Typhimurium and Campylobacter appear to be more ubiquitous in the environment, colonising a greater variety of hosts and environmental niches. Verocytotoxin-producing Escherichia coli O157 (VTEC O157) also emerged as a major food-borne zoonotic pathogen in the 1980s and 1990s. Although infection is relatively rare in humans, clinical disease is often severe, with a significant mortality rate among the young and elderly. The epidemiology of VTEC O157 is poorly understood, although ruminants, especially cattle and sheep, appear to be the major source of infection. The dissemination of S. Enteritidis along the food chain is fairly well understood, and control programmes have been developed to target key areas of poultry meat and egg production. Recent evidence indicates that these control programmes have been associated with an overall reduction of S. Enteritidis along the food chain. Unfortunately, existing controls do not appear to reduce the levels of Campylobacter and VTEC O157 infections. Future control strategies need to consider variations in the epidemiologies of food-borne zoonotic infections, and apply a quantitative risk analysis approach to ensure that the most cost-effective programmes are developed.

  13. Integrated vector management for malaria control

    Directory of Open Access Journals (Sweden)

    Impoinvil Daniel E

    2008-12-01

    Full Text Available Abstract Integrated vector management (IVM is defined as "a rational decision-making process for the optimal use of resources for vector control" and includes five key elements: 1 evidence-based decision-making, 2 integrated approaches 3, collaboration within the health sector and with other sectors, 4 advocacy, social mobilization, and legislation, and 5 capacity-building. In 2004, the WHO adopted IVM globally for the control of all vector-borne diseases. Important recent progress has been made in developing and promoting IVM for national malaria control programmes in Africa at a time when successful malaria control programmes are scaling-up with insecticide-treated nets (ITN and/or indoor residual spraying (IRS coverage. While interventions using only ITNs and/or IRS successfully reduce transmission intensity and the burden of malaria in many situations, it is not clear if these interventions alone will achieve those critical low levels that result in malaria elimination. Despite the successful employment of comprehensive integrated malaria control programmes, further strengthening of vector control components through IVM is relevant, especially during the "end-game" where control is successful and further efforts are required to go from low transmission situations to sustained local and country-wide malaria elimination. To meet this need and to ensure sustainability of control efforts, malaria control programmes should strengthen their capacity to use data for decision-making with respect to evaluation of current vector control programmes, employment of additional vector control tools in conjunction with ITN/IRS tactics, case-detection and treatment strategies, and determine how much and what types of vector control and interdisciplinary input are required to achieve malaria elimination. Similarly, on a global scale, there is a need for continued research to identify and evaluate new tools for vector control that can be integrated with

  14. Noncausal Bayesian Vector Autoregression

    DEFF Research Database (Denmark)

    Lanne, Markku; Luoto, Jani

    We propose a Bayesian inferential procedure for the noncausal vector autoregressive (VAR) model that is capable of capturing nonlinearities and incorporating effects of missing variables. In particular, we devise a fast and reliable posterior simulator that yields the predictive distribution...

  15. Understanding Vector Fields.

    Science.gov (United States)

    Curjel, C. R.

    1990-01-01

    Presented are activities that help students understand the idea of a vector field. Included are definitions, flow lines, tangential and normal components along curves, flux and work, field conservation, and differential equations. (KR)

  16. GAP Land Cover - Vector

    Data.gov (United States)

    Minnesota Department of Natural Resources — This vector dataset is a detailed (1-acre minimum), hierarchically organized vegetation cover map produced by computer classification of combined two-season pairs of...

  17. Sesquilinear uniform vector integral

    Indian Academy of Sciences (India)

    theory, together with his integral, dominate contemporary mathematics. ... directions belonging to Bartle and Dinculeanu (see [1], [6], [7] and [2]). ... in this manner, namely he integrated vector functions with respect to measures of bounded.

  18. Tagged Vector Contour (TVC)

    Data.gov (United States)

    Kansas Data Access and Support Center — The Kansas Tagged Vector Contour (TVC) dataset consists of digitized contours from the 7.5 minute topographic quadrangle maps. Coverage for the state is incomplete....

  19. Vector hysteresis models

    Czech Academy of Sciences Publication Activity Database

    Krejčí, Pavel

    1991-01-01

    Roč. 2, - (1991), s. 281-292 ISSN 0956-7925 Keywords : vector hysteresis operator * hysteresis potential * differential inequality Subject RIV: BA - General Mathematics http://www.math.cas.cz/~krejci/b15p.pdf

  20. Support vector machines applications

    CERN Document Server

    Guo, Guodong

    2014-01-01

    Support vector machines (SVM) have both a solid mathematical background and good performance in practical applications. This book focuses on the recent advances and applications of the SVM in different areas, such as image processing, medical practice, computer vision, pattern recognition, machine learning, applied statistics, business intelligence, and artificial intelligence. The aim of this book is to create a comprehensive source on support vector machine applications, especially some recent advances.

  1. Exotic composite vector boson

    International Nuclear Information System (INIS)

    Akama, K.; Hattori, T.; Yasue, M.

    1991-01-01

    An exotic composite vector boson V is introduced in two dynamical models of composite quarks, leptons, W, and Z. One is based on four-Fermi interactions, in which composite vector bosons are regarded as fermion-antifermion bound states and the other is based on the confining SU(2) L gauge model, in which they are given by scalar-antiscalar bound states. Both approaches describe the same effective interactions for the sector of composite quarks, leptons, W, Z, γ, and V

  2. Vector financial rogue waves

    International Nuclear Information System (INIS)

    Yan, Zhenya

    2011-01-01

    The coupled nonlinear volatility and option pricing model presented recently by Ivancevic is investigated, which generates a leverage effect, i.e., stock volatility is (negatively) correlated to stock returns, and can be regarded as a coupled nonlinear wave alternative of the Black–Scholes option pricing model. In this Letter, we analytically propose vector financial rogue waves of the coupled nonlinear volatility and option pricing model without an embedded w-learning. Moreover, we exhibit their dynamical behaviors for chosen different parameters. The vector financial rogue wave (rogon) solutions may be used to describe the possible physical mechanisms for the rogue wave phenomena and to further excite the possibility of relative researches and potential applications of vector rogue waves in the financial markets and other related fields. -- Highlights: ► We investigate the coupled nonlinear volatility and option pricing model. ► We analytically present vector financial rogue waves. ► The vector financial rogue waves may be used to describe the extreme events in financial markets. ► This results may excite the relative researches and potential applications of vector rogue waves.

  3. An attempt of rationalization of tick-borne disease prevention using a multifunctional container for Tick Twister ®

    Directory of Open Access Journals (Sweden)

    Barbara Oczko-Grzesik

    2013-12-01

    Full Text Available Ticks are reservoir and transmission vectors of many bacteria, viruses and parasites, which are pathogenic for humans. Early and correct tick removal is crucial as prevention of tick-borne diseases. The aim of the study is an attempt at rationalization of tick-borne disease prevention using a multifunctional container for Tick Twister®. In practice, it should enable people to use Tick Twister® in all circumstances contributing to the improvement of efficiency in tick-borne diseases prevention, and as a result, to a decrease in their frequency and after effects.

  4. Vectorization in quantum chemistry

    International Nuclear Information System (INIS)

    Saunders, V.R.

    1987-01-01

    It is argued that the optimal vectorization algorithm for many steps (and sub-steps) in a typical ab initio calculation of molecular electronic structure is quite strongly dependent on the target vector machine. Details such as the availability (or lack) of a given vector construct in the hardware, vector startup times and asymptotic rates must all be considered when selecting the optimal algorithm. Illustrations are drawn from: gaussian integral evaluation, fock matrix construction, 4-index transformation of molecular integrals, direct-CI methods, the matrix multiply operation. A cross comparison of practical implementations on the CDC Cyber 205, the Cray-IS and Cray-XMP machines is presented. To achieve portability while remaining optimal on a wide range of machines it is necessary to code all available algorithms in a machine independent manner, and to select the appropriate algorithm using a procedure which is based on machine dependent parameters. Most such parameters concern the timing of certain vector loop kernals, which can usually be derived from a 'bench-marking' routine executed prior to the calculation proper

  5. Vector Fields on Product Manifolds

    OpenAIRE

    Kurz, Stefan

    2011-01-01

    This short report establishes some basic properties of smooth vector fields on product manifolds. The main results are: (i) On a product manifold there always exists a direct sum decomposition into horizontal and vertical vector fields. (ii) Horizontal and vertical vector fields are naturally isomorphic to smooth families of vector fields defined on the factors. Vector fields are regarded as derivations of the algebra of smooth functions.

  6. We have "born digital" - now what about "born semantic"?

    Science.gov (United States)

    Leadbetter, Adam; Fredericks, Janet

    2014-05-01

    The phrase "born-digital" refers to those materials which originate in a digital form. In Earth and Space Sciences, this is now very much the norm for data: analogue to digital converters sit on instrument boards and produce a digital record of the observed environment. While much effort has been put in to creating and curating these digital data, there has been little work on using semantic mark up of data from the point of collection - what we term 'born semantic'. In this presentation we report on two efforts to expand this area: Qartod-to-OGC (Q2O) and SenseOCEAN. These projects have taken a common approach to 'born semantic': create or reuse appropriate controlled vocabularies, published to World Wide Web Commission (W3C) standards use standards from the Open Geospatial Consortium's Sensor Web Enablement (SWE) initiative to describe instrument setup, deployment and/or outputs using terms from those controlled vocabularies embed URLs from the controlled vocabularies within the SWE documents in a "Linked Data" conformant approach Q2O developed best practices examples of SensorML descriptions of Original Equipment Manufacturers' metadata (model characteristics, capabilities, manufacturer contact, etc ...) set-up and deployment SensorML files; and data centre process-lineage using registered vocabularies to describe terms (including input, output, processes, parameters, quality control flags) One Q2O use case, the Martha's Vineyard Coastal Observatory ADCP Waves instance, uses SensorML and registered vocabularies to fully describe the process of computing wave parameters from sensed properties, including quality control tests and associated results. The European Commission Framework Programme 7 project SenseOCEAN draws together world leading marine sensor developers to create a highly integrated multifunction and cost-effective in situ marine biogeochemical sensor system. This project will provide a quantum leap in the ability to measure crucial biogeochemical

  7. Surgical experts: born or made?

    Science.gov (United States)

    Sadideen, Hazim; Alvand, Abtin; Saadeddin, Munir; Kneebone, Roger

    2013-01-01

    The concept of surgical expertise and the processes involved in its development are topical, and there is a constant drive to identify reliable measures of expert performance in surgery. This review explores the notion of whether surgical experts are "born" or "made", with reference to educational theory and pertinent literature. Peer-reviewed publications, books, and online resources on surgical education, expertise and training were reviewed. Important themes and aspects of expertise acquisition were identified in order to better understand the concept of a surgical expert. The definition of surgical expertise and several important aspects of its development are highlighted. Innate talent plays an important role, but is insufficient on its own to produce a surgical expert. Multiple theories that explore motor skill acquisition and memory are relevant, and Ericsson's theory of the development of competence followed by deliberate self-practice has been especially influential. Psychomotor and non-technical skills are necessary for progression in the current climate in light of our training curricula; surgical experts are adaptive experts who excel in these. The literature suggests that surgical expertise is reached through practice; surgical experts are made, not born. A deeper understanding of the nature of expert performance and its development will ensure that surgical education training programmes are of the highest possible quality. Surgical educators should aim to develop an expertise-based approach, with expert performance as the benchmark. Copyright © 2013 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  8. Launching the first postgraduate diploma in medical entomology and disease vector control in Pakistan.

    Science.gov (United States)

    Rathor, H R; Mnzava, A; Bile, K M; Hafeez, A; Zaman, S

    2010-01-01

    The Health Services Academy has launched a 12-month postgraduate diploma course in medical entomology and disease vector control. The objective is to create a core of experts trained to prevent and control vector-borne diseases. The course is a response to the serious health and socioeconomic burden caused by a number of vector-borne diseases in Pakistan. The persistence, emergence and re-emergence of these diseases is mainly attributed to the scarcity of trained vector-control experts. The training course attempts to fill the gap in trained manpower and thus reduce the morbidity and mortality due to these diseases, resulting in incremental gains to public health. This paper aims to outline the steps taken to establish the course and the perceived challenges to be addressed in order to sustain its future implementation.

  9. Bunyavirus-Vector Interactions

    Directory of Open Access Journals (Sweden)

    Kate McElroy Horne

    2014-11-01

    Full Text Available The Bunyaviridae family is comprised of more than 350 viruses, of which many within the Hantavirus, Orthobunyavirus, Nairovirus, Tospovirus, and Phlebovirus genera are significant human or agricultural pathogens. The viruses within the Orthobunyavirus, Nairovirus, and Phlebovirus genera are transmitted by hematophagous arthropods, such as mosquitoes, midges, flies, and ticks, and their associated arthropods not only serve as vectors but also as virus reservoirs in many cases. This review presents an overview of several important emerging or re-emerging bunyaviruses and describes what is known about bunyavirus-vector interactions based on epidemiological, ultrastructural, and genetic studies of members of this virus family.

  10. Sums and Gaussian vectors

    CERN Document Server

    Yurinsky, Vadim Vladimirovich

    1995-01-01

    Surveys the methods currently applied to study sums of infinite-dimensional independent random vectors in situations where their distributions resemble Gaussian laws. Covers probabilities of large deviations, Chebyshev-type inequalities for seminorms of sums, a method of constructing Edgeworth-type expansions, estimates of characteristic functions for random vectors obtained by smooth mappings of infinite-dimensional sums to Euclidean spaces. A self-contained exposition of the modern research apparatus around CLT, the book is accessible to new graduate students, and can be a useful reference for researchers and teachers of the subject.

  11. Duality in vector optimization

    CERN Document Server

    Bot, Radu Ioan

    2009-01-01

    This book presents fundamentals and comprehensive results regarding duality for scalar, vector and set-valued optimization problems in a general setting. After a preliminary chapter dedicated to convex analysis and minimality notions of sets with respect to partial orderings induced by convex cones a chapter on scalar conjugate duality follows. Then investigations on vector duality based on scalar conjugacy are made. Weak, strong and converse duality statements are delivered and connections to classical results from the literature are emphasized. One chapter is exclusively consecrated to the s

  12. Multithreading in vector processors

    Science.gov (United States)

    Evangelinos, Constantinos; Kim, Changhoan; Nair, Ravi

    2018-01-16

    In one embodiment, a system includes a processor having a vector processing mode and a multithreading mode. The processor is configured to operate on one thread per cycle in the multithreading mode. The processor includes a program counter register having a plurality of program counters, and the program counter register is vectorized. Each program counter in the program counter register represents a distinct corresponding thread of a plurality of threads. The processor is configured to execute the plurality of threads by activating the plurality of program counters in a round robin cycle.

  13. Matrix vector analysis

    CERN Document Server

    Eisenman, Richard L

    2005-01-01

    This outstanding text and reference applies matrix ideas to vector methods, using physical ideas to illustrate and motivate mathematical concepts but employing a mathematical continuity of development rather than a physical approach. The author, who taught at the U.S. Air Force Academy, dispenses with the artificial barrier between vectors and matrices--and more generally, between pure and applied mathematics.Motivated examples introduce each idea, with interpretations of physical, algebraic, and geometric contexts, in addition to generalizations to theorems that reflect the essential structur

  14. Free topological vector spaces

    OpenAIRE

    Gabriyelyan, Saak S.; Morris, Sidney A.

    2016-01-01

    We define and study the free topological vector space $\\mathbb{V}(X)$ over a Tychonoff space $X$. We prove that $\\mathbb{V}(X)$ is a $k_\\omega$-space if and only if $X$ is a $k_\\omega$-space. If $X$ is infinite, then $\\mathbb{V}(X)$ contains a closed vector subspace which is topologically isomorphic to $\\mathbb{V}(\\mathbb{N})$. It is proved that if $X$ is a $k$-space, then $\\mathbb{V}(X)$ is locally convex if and only if $X$ is discrete and countable. If $X$ is a metrizable space it is shown ...

  15. Scalar-vector bootstrap

    Energy Technology Data Exchange (ETDEWEB)

    Rejon-Barrera, Fernando [Institute for Theoretical Physics, University of Amsterdam,Science Park 904, Postbus 94485, 1090 GL, Amsterdam (Netherlands); Robbins, Daniel [Department of Physics, Texas A& M University,TAMU 4242, College Station, TX 77843 (United States)

    2016-01-22

    We work out all of the details required for implementation of the conformal bootstrap program applied to the four-point function of two scalars and two vectors in an abstract conformal field theory in arbitrary dimension. This includes a review of which tensor structures make appearances, a construction of the projectors onto the required mixed symmetry representations, and a computation of the conformal blocks for all possible operators which can be exchanged. These blocks are presented as differential operators acting upon the previously known scalar conformal blocks. Finally, we set up the bootstrap equations which implement crossing symmetry. Special attention is given to the case of conserved vectors, where several simplifications occur.

  16. The Insect Microbiome Modulates Vector Competence for Arboviruses

    Directory of Open Access Journals (Sweden)

    Natapong Jupatanakul

    2014-11-01

    Full Text Available Diseases caused by arthropod-borne viruses (arboviruses, such as Dengue, West Nile, and Chikungunya, constitute a major global health burden and are increasing in incidence and geographic range. The natural microbiota of insect vectors influences various aspects of host biology, such as nutrition, reproduction, metabolism, and immunity, and recent studies have highlighted the ability of insect-associated bacteria to reduce vector competence for arboviruses and other pathogens. This reduction can occur through mechanisms, such as immune response activation, resource competition, or the production of anti-viral molecules. Studying the interactions between insect vectors and their microbiota is an important step toward developing alternative strategies for arbovirus transmission control.

  17. Vaccination strategies for SIR vector-transmitted diseases.

    Science.gov (United States)

    Cruz-Pacheco, Gustavo; Esteva, Lourdes; Vargas, Cristobal

    2014-08-01

    Vector-borne diseases are one of the major public health problems in the world with the fastest spreading rate. Control measures have been focused on vector control, with poor results in most cases. Vaccines should help to reduce the diseases incidence, but vaccination strategies should also be defined. In this work, we propose a vector-transmitted SIR disease model with age-structured population subject to a vaccination program. We find an expression for the age-dependent basic reproductive number R(0), and we show that the disease-free equilibrium is locally stable for R(0) ≤ 1, and a unique endemic equilibrium exists for R(0) > 1. We apply the theoretical results to public data to evaluate vaccination strategies, immunization levels, and optimal age of vaccination for dengue disease.

  18. [Vector transmitted diseases and climate changes in Europe].

    Science.gov (United States)

    Rossati, Antonella; Bargiacchi, Olivia; Kroumova, Vesselina; Garavelli, Pietro Luigi

    2014-09-01

    The increase in temperatures recorded since the mid-nineteenth century is unprecedented in the history of mankind. The consequences of climate changes are numerous and can affect human health through direct (extreme events, natural disasters) or indirect (alteration of the ecosystem) mechanisms. Climate changes have repercussions on ecosystems, agriculture, social conditions, migration, conflicts and the transmission mode of infectious diseases. Vector-borne diseases are infections transmitted by the bite of infected arthropods such as mosquitoes, ticks, triatomines, sand flies and flies. Epidemiological cornerstones of vector-borne diseases are: the ecology and behaviour of the host, the ecology and behaviour of the vector, and the population's degree of immunity. Mosquito vectors related to human diseases mainly belong to the genus Culex, Aedes and Mansonia. Climate changes in Europe have increased the spread of new vectors, such as Aedes albopictus, and in some situations have made it possible to sustain the autochthonous transmission of some diseases (outbreak of Chukungunya virus in northern Italy in 2007, cases of dengue in the South of France and in Croatia). Despite the eradication of malaria from Europe, anopheline carriers are still present, and they may allow the transmission of the disease if the climatic conditions favour the development of the vectors and their contacts with plasmodium carriers. The tick Ixodes ricinus is a vector whose expansion has been documented both in latitude and in altitude in relation to the temperature increase; at the same time the related main viral and bacterial infections have increased. In northern Italy and Germany, the appearance of Leishmaniasis has been associated to climatic conditions that favour the development of the vector Phlebotomus papatasi and the maturation of the parasite within the vector, although the increase of cases of visceral leishmaniasis is also related to host immune factors, particularly

  19. Estimation of vector velocity

    DEFF Research Database (Denmark)

    2000-01-01

    Using a pulsed ultrasound field, the two-dimensional velocity vector can be determined with the invention. The method uses a transversally modulated ultrasound field for probing the moving medium under investigation. A modified autocorrelation approach is used in the velocity estimation. The new...

  20. Production of lentiviral vectors

    Directory of Open Access Journals (Sweden)

    Otto-Wilhelm Merten

    2016-01-01

    Full Text Available Lentiviral vectors (LV have seen considerably increase in use as gene therapy vectors for the treatment of acquired and inherited diseases. This review presents the state of the art of the production of these vectors with particular emphasis on their large-scale production for clinical purposes. In contrast to oncoretroviral vectors, which are produced using stable producer cell lines, clinical-grade LV are in most of the cases produced by transient transfection of 293 or 293T cells grown in cell factories. However, more recent developments, also, tend to use hollow fiber reactor, suspension culture processes, and the implementation of stable producer cell lines. As is customary for the biotech industry, rather sophisticated downstream processing protocols have been established to remove any undesirable process-derived contaminant, such as plasmid or host cell DNA or host cell proteins. This review compares published large-scale production and purification processes of LV and presents their process performances. Furthermore, developments in the domain of stable cell lines and their way to the use of production vehicles of clinical material will be presented.

  1. Orthogonalisation of Vectors

    Indian Academy of Sciences (India)

    The Gram-Schmidt process is one of the first things one learns in a course ... We might want to stay as close to the experimental data as possible when converting these vectors to orthonormal ones demanded by the model. The process of finding the closest or- thonormal .... is obtained by writing the matrix A = [aI, an], then.

  2. From vectors to mnesors

    OpenAIRE

    Champenois, Gilles

    2007-01-01

    The mnesor theory is the adaptation of vectors to artificial intelligence. The scalar field is replaced by a lattice. Addition becomes idempotent and multiplication is interpreted as a selection operation. We also show that mnesors can be the foundation for a linear calculus.

  3. Calculus with vectors

    CERN Document Server

    Treiman, Jay S

    2014-01-01

    Calculus with Vectors grew out of a strong need for a beginning calculus textbook for undergraduates who intend to pursue careers in STEM. fields. The approach introduces vector-valued functions from the start, emphasizing the connections between one-variable and multi-variable calculus. The text includes early vectors and early transcendentals and includes a rigorous but informal approach to vectors. Examples and focused applications are well presented along with an abundance of motivating exercises. All three-dimensional graphs have rotatable versions included as extra source materials and may be freely downloaded and manipulated with Maple Player; a free Maple Player App is available for the iPad on iTunes. The approaches taken to topics such as the derivation of the derivatives of sine and cosine, the approach to limits, and the use of "tables" of integration have been modified from the standards seen in other textbooks in order to maximize the ease with which students may comprehend the material. Additio...

  4. On vector equilibrium problem

    Indian Academy of Sciences (India)

    [G] Giannessi F, Theorems of alternative, quadratic programs and complementarity problems, in: Variational Inequalities and Complementarity Problems (eds) R W Cottle, F Giannessi and J L Lions (New York: Wiley) (1980) pp. 151±186. [K1] Kazmi K R, Existence of solutions for vector optimization, Appl. Math. Lett. 9 (1996).

  5. Conceptualizing Innovation in Born Global Firms

    DEFF Research Database (Denmark)

    Zijdemans, Erik; Tanev, Stoyan

    2014-01-01

    This research provides insights from recent literature on innovativeness in the environment of born globals. This article will be relevant to researchers interested in born globals and their business environments and, more specifically, the role that innovation plays in their foundation and devel...... of knowledge acquisition, networking capabilities and the lean startup approach in born global innovation. Finally, the article addresses the issue of quantifying and measuring innovativeness....

  6. Ixodes ricinus ticks are reservoir hosts for Rickettsia helvetica and potentially carry flea-borne Rickettsia species.

    NARCIS (Netherlands)

    Sprong, H.; Wielinga, P.R.; Fonville, M.; Reusken, C.; Brandenburg, A.H.; Borgsteede, F.H.M.

    2009-01-01

    Background - Hard ticks have been identified as important vectors of rickettsiae causing the spotted fever syndrome. Tick-borne rickettsiae are considered to be emerging, but only limited data are available about their presence in Western Europe, their natural life cycle and their reservoir hosts.

  7. Current vector control challenges in the fight against malaria.

    Science.gov (United States)

    Benelli, Giovanni; Beier, John C

    2017-10-01

    The effective and eco-friendly control of Anopheles vectors plays a key role in any malaria management program. Integrated Vector Management (IVM) suggests making use of the full range of vector control tools available. The strategies for IVM require novel technologies to control outdoor transmission of malaria. Despite the wide number of promising control tools tested against mosquitoes, current strategies for malaria vector control used in most African countries are not sufficient to achieve successful malaria control. The majority of National Malaria Control Programs in Africa still rely on indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs). These methods reduce malaria incidence but generally have little impact on malaria prevalence. In addition to outdoor transmission, growing levels of insecticide resistance in targeted vectors threaten the efficacy of LLINs and IRS. Larvicidal treatments can be useful, but are not recommended for rural areas. The research needed to improve the quality and delivery of mosquito vector control should focus on (i) optimization of processes and methods for vector control delivery; (ii) monitoring of vector populations and biting activity with reliable techniques; (iii) the development of effective and eco-friendly tools to reduce the burden or locally eliminate malaria and other mosquito-borne diseases; (iv) the careful evaluation of field suitability and efficacy of new mosquito control tools to prove their epidemiological impact; (v) the continuous monitoring of environmental changes which potentially affect malaria vector populations; (vi) the cooperation among different disciplines, with main emphasis on parasitology, tropical medicine, ecology, entomology, and ecotoxicology. A better understanding of behavioral ecology of malaria vectors is required. Key ecological obstacles that limit the effectiveness of vector control include the variation in mosquito behavior, development of insecticide resistance

  8. VECTORS OF MALARIA AND FILARIASIS IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Hoedojo Hoedojo

    2012-09-01

    Full Text Available Malaria at present is still one of the important mosquito-borne diseases in Indonesia. The disease is widespread all over the country and involves nearly all islands. Sixteen Anopheles species have been reconfirmed as malaria vectors. They were distributed geographi­cally as follows: Coastal areas and lagoons ------------------------------------- An sundaicus and An.subpictus Cultivated ricefields and swampy areas -------------------- An.aconitus, An.barbirostris, An.nigerrimus and An.sinensis Forest inland areas in shaded temporary pools, muddy animal wallows and hoof-prints -------------------------------------------------------- An.balabacensis, An.bancrofti, An.farauti, An.koliensis and An.punctulatus Swamp forest edge in ditches with vegeta- ---------------- An.letifer and An.ludlowae don Hilly areas in seepages, streams and clear moving water ---------------------------------------------- Anflavirostris, An.maculatus and Anminimus.   The species (of most general importance is An.sundaicus, which is restricted by its preference for brackish water and is prevalent in coastal areas of Java. Their types in behaviour of An.sundaicus appear as follows : 1. An.sundaicus in South Coast of Java in general. This species is essentially anthropophilic, exophagic and rests outdoor. It shows susceptible to DDT. 2. An.sundaicus in Cilacap, Central Java. This mosquito is a pure anthropophilic form. It bites man in houses and outdoors, rests indoors and is known resistant to DDT. 3. An.sundaicus in Yogyakarta and Purworejo, Central Java. This mosquito is a strong zoophilic species. It rests and prefers to bite outdoors and shows tolerance to DDT. Human filariasis in Indonesia is the result of infection by three endemic species, namely, Wuchereria bancrofti, Brugia malayi, and Brugia timori.W.bancrofti infection is found in both urban and rural areas. Twenty species of mosquitoes are confirmed as filariasis vectors. The urban type bancroftian filariasis

  9. Insecticide resistance in disease vectors from Mayotte: an opportunity for integrated vector management.

    Science.gov (United States)

    Pocquet, Nicolas; Darriet, Frédéric; Zumbo, Betty; Milesi, Pascal; Thiria, Julien; Bernard, Vincent; Toty, Céline; Labbé, Pierrick; Chandre, Fabrice

    2014-07-01

    Mayotte, a small island in the Indian Ocean, has been affected for many years by vector-borne diseases. Malaria, Bancroftian filariasis, dengue, chikungunya and Rift Valley fever have circulated or still circulate on the island. They are all transmitted by Culicidae mosquitoes. To limit the impact of these diseases on human health, vector control has been implemented for more than 60 years on Mayotte. In this study, we assessed the resistance levels of four major vector species (Anopheles gambiae, Culex pipiens quinquefasciatus, Aedes aegypti and Aedes albopictus) to two types of insecticides: i) the locally currently-used insecticides (organophosphates, pyrethroids) and ii) alternative molecules that are promising for vector control and come from different insecticide families (bacterial toxins or insect growth regulators). When some resistance was found to one of these insecticides, we characterized the mechanisms involved. Larval and adult bioassays were used to evaluate the level of resistance. When resistance was found, we tested for the presence of metabolic resistance through detoxifying enzyme activity assays, or for target-site mutations through molecular identification of known resistance alleles. Resistance to currently-used insecticides varied greatly between the four vector species. While no resistance to any insecticides was found in the two Aedes species, bioassays confirmed multiple resistance in Cx. p. quinquefasciatus (temephos: ~ 20 fold and deltamethrin: only 10% mortality after 24 hours). In An. gambiae, resistance was scarce: only a moderate resistance to temephos was found (~5 fold). This resistance appears to be due only to carboxyl-esterase overexpression and not to target modification. Finally, and comfortingly, none of the four species showed resistance to any of the new insecticides. The low resistance observed in Mayotte's main disease vectors is particularly interesting, because it leaves a range of tools useable by vector control

  10. Animal Models of Tick-Borne Hemorrhagic Fever Viruses

    Directory of Open Access Journals (Sweden)

    Heinz Feldmann

    2013-05-01

    Full Text Available Tick-borne hemorrhagic fever viruses (TBHFV are detected throughout the African and Eurasian continents and are an emerging or re-emerging threat to many nations. Due to the largely sporadic incidences of these severe diseases, information on human cases and research activities in general have been limited. In the past decade, however, novel TBHFVs have emerged and areas of endemicity have expanded. Therefore, the development of countermeasures is of utmost importance in combating TBHFV as elimination of vectors and interrupting enzootic cycles is all but impossible and ecologically questionable. As in vivo models are the only way to test efficacy and safety of countermeasures, understanding of the available animal models and the development and refinement of animal models is critical in negating the detrimental impact of TBHFVs on public and animal health.

  11. Vector grammars and PN machines

    Institute of Scientific and Technical Information of China (English)

    蒋昌俊

    1996-01-01

    The concept of vector grammars under the string semantic is introduced.The dass of vector grammars is given,which is similar to the dass of Chomsky grammars.The regular vector grammar is divided further.The strong and weak relation between the vector grammar and scalar grammar is discussed,so the spectrum system graph of scalar and vector grammars is made.The equivalent relation between the regular vector grammar and Petri nets (also called PN machine) is pointed.The hybrid PN machine is introduced,and its language is proved equivalent to the language of the context-free vector grammar.So the perfect relation structure between vector grammars and PN machines is formed.

  12. Epidemiology and control of malaria and other arthropod born diseases

    Directory of Open Access Journals (Sweden)

    F. J. López-Antuñano

    1992-01-01

    Full Text Available Malaria and other arthropod born diseases remain a serious public health problem affecting the lives and health of certain social groups when the two basic strategies to control fail due to : (1 the lack of effective chemoprophylaxis/chemotherapy or the rapid development of drug resistance of the infectious agents and (2 the ineffectiveness of pesticides or the arthropod vectors develop resistance to them. These situations enhances the need for the design and implementation of other alternatives for sustainable health programmes. The application of the epidemiological methods is essential not only for analyzing the relevant data for the understanding of the biological characteristics of the infectious agents, their reservoirs and vectors and the methods for their control, but also for the assessment of the human behaviour, the environmental, social and economic factors involved in disease transmission and the capacity of the health systems to implement interventions for both changes in human behaviour and environmental management to purpose guaranteed prevention and control of malaria and other arthropod born diseases with efficiency, efficacy and equity. This paper discuss the evolution of the malaria arthropod diseases programmes in the American Region and the perspectives for their integration into health promotion programs and emphasis is made in the need to establish solid basis in the decision-making process for the selection of intervention strategies to remove the risk factors determining the probability to get sick or die from ABDs. The implications of the general planning and the polices to be adopted in an area should be analyzed in the light of programme feasibility at the local level, in the multisectoral context specific social groups and taking in consideration the principles of stratification and equity

  13. Arthropod-Borne Diseases: The Camper's Uninvited Guests.

    Science.gov (United States)

    Juckett, Gregory

    2015-08-01

    Arthropod-borne diseases are a major problem whenever outdoor activities bring arthropods and people into contact. The arthropods discussed here include arachnids (ticks) and insects. Most arthropod bites and stings are minor, with the notable exception being bee-sting anaphylaxis. Ticks cause the most disease transmission. Key hard tick vectors include black-legged (Ixodes), dog (Dermacentor), and lone star (Amblyomma) ticks, which transmit Lyme and various rickettsial diseases. Insect repellents, permethrin sprays, and proper tick inspection reduce this risk significantly. Lyme disease and the milder southern-tick-associated rash illness (STARI) are characterized by the erythema migrans rash followed, in the case of Lyme disease, by early, disseminated, and late systemic symptoms. Treatment is with doxycycline or ceftriaxone. Indefinite treatment of "chronic Lyme disease" based on subjective symptoms is not beneficial. Rickettsial diseases include ehrlichiosis, anaplasmosis, and Rocky Mountain spotted fever, which are characterized by fever, headache, and possible rash and should be empirically treated with doxycycline while awaiting laboratory confirmation. Tularemia is a bacterial disease (Francisella) spread by ticks and rabbits and characterized by fever and adenopathy. Treatment is with gentamicin or streptomycin. Babesiosis is a protozoal disease, mimicking malaria, that causes a self-limited flu-like disease in healthy hosts but can be life threatening with immune compromise. Treatment is with atovaquone and azithromycin. Other tick-related conditions include viral diseases (Powassan, Colorado tick fever, heartland virus), tick-borne relapsing fever (Borrelia), and tick paralysis (toxin). Mosquitoes, lice, fleas, and mites are notable for their annoying bites but are increasingly significant disease vectors even in the United States.

  14. Quantifying and resolving multiple vector transformants in S. cerevisiae plasmid libraries.

    Science.gov (United States)

    Scanlon, Thomas C; Gray, Elizabeth C; Griswold, Karl E

    2009-11-20

    In addition to providing the molecular machinery for transcription and translation, recombinant microbial expression hosts maintain the critical genotype-phenotype link that is essential for high throughput screening and recovery of proteins encoded by plasmid libraries. It is known that Escherichia coli cells can be simultaneously transformed with multiple unique plasmids and thusly complicate recombinant library screening experiments. As a result of their potential to yield misleading results, bacterial multiple vector transformants have been thoroughly characterized in previous model studies. In contrast to bacterial systems, there is little quantitative information available regarding multiple vector transformants in yeast. Saccharomyces cerevisiae is the most widely used eukaryotic platform for cell surface display, combinatorial protein engineering, and other recombinant library screens. In order to characterize the extent and nature of multiple vector transformants in this important host, plasmid-born gene libraries constructed by yeast homologous recombination were analyzed by DNA sequencing. It was found that up to 90% of clones in yeast homologous recombination libraries may be multiple vector transformants, that on average these clones bear four or more unique mutant genes, and that these multiple vector cells persist as a significant proportion of library populations for greater than 24 hours during liquid outgrowth. Both vector concentration and vector to insert ratio influenced the library proportion of multiple vector transformants, but their population frequency was independent of transformation efficiency. Interestingly, the average number of plasmids born by multiple vector transformants did not vary with their library population proportion. These results highlight the potential for multiple vector transformants to dominate yeast libraries constructed by homologous recombination. The previously unrecognized prevalence and persistence of multiply

  15. Quantifying and resolving multiple vector transformants in S. cerevisiae plasmid libraries

    Directory of Open Access Journals (Sweden)

    Gray Elizabeth C

    2009-11-01

    Full Text Available Abstract Background In addition to providing the molecular machinery for transcription and translation, recombinant microbial expression hosts maintain the critical genotype-phenotype link that is essential for high throughput screening and recovery of proteins encoded by plasmid libraries. It is known that Escherichia coli cells can be simultaneously transformed with multiple unique plasmids and thusly complicate recombinant library screening experiments. As a result of their potential to yield misleading results, bacterial multiple vector transformants have been thoroughly characterized in previous model studies. In contrast to bacterial systems, there is little quantitative information available regarding multiple vector transformants in yeast. Saccharomyces cerevisiae is the most widely used eukaryotic platform for cell surface display, combinatorial protein engineering, and other recombinant library screens. In order to characterize the extent and nature of multiple vector transformants in this important host, plasmid-born gene libraries constructed by yeast homologous recombination were analyzed by DNA sequencing. Results It was found that up to 90% of clones in yeast homologous recombination libraries may be multiple vector transformants, that on average these clones bear four or more unique mutant genes, and that these multiple vector cells persist as a significant proportion of library populations for greater than 24 hours during liquid outgrowth. Both vector concentration and vector to insert ratio influenced the library proportion of multiple vector transformants, but their population frequency was independent of transformation efficiency. Interestingly, the average number of plasmids born by multiple vector transformants did not vary with their library population proportion. Conclusion These results highlight the potential for multiple vector transformants to dominate yeast libraries constructed by homologous recombination. The

  16. Vehicle Based Vector Sensor

    Science.gov (United States)

    2015-09-28

    buoyant underwater vehicle with an interior space in which a length of said underwater vehicle is equal to one tenth of the acoustic wavelength...underwater vehicle with an interior space in which a length of said underwater vehicle is equal to one tenth of the acoustic wavelength; an...unmanned underwater vehicle that can function as an acoustic vector sensor. (2) Description of the Prior Art [0004] It is known that a propagating

  17. Reciprocity in Vector Acoustics

    Science.gov (United States)

    2017-03-01

    Green’s Theorem to the left hand side of Equation (3.2) converts it to a surface integral that vanishes for the impedance boundary conditions one...There are situations where this assumption does not hold, such as at boundaries between layers or in an inhomogeneous layer , because the density gradient...instead of requiring one model run for each source location. Application of the vector-scalar reciprocity principle is demonstrated with analytic

  18. Non-abelian Born-Infeld revisited

    NARCIS (Netherlands)

    Roo, M. de

    2002-01-01

    We discuss the non-abelian Born-Infeld action, including fermions, as a series in α'. We review recent work establishing the complete result to α'2, and its impact on our earlier attempts to derive the Born-Infeld action using κ-symmetry.

  19. Tensor Calculus: Unlearning Vector Calculus

    Science.gov (United States)

    Lee, Wha-Suck; Engelbrecht, Johann; Moller, Rita

    2018-01-01

    Tensor calculus is critical in the study of the vector calculus of the surface of a body. Indeed, tensor calculus is a natural step-up for vector calculus. This paper presents some pitfalls of a traditional course in vector calculus in transitioning to tensor calculus. We show how a deeper emphasis on traditional topics such as the Jacobian can…

  20. Tick-borne encephalitis: a disease neglected by travel medicine.

    Science.gov (United States)

    Haditsch, Martin; Kunze, Ursula

    2013-01-01

    Tick-borne encephalitis (TBE) is a vector-borne disease that is primarily transmitted to humans by infected ticks and causes infection of the central nervous system. Clinical presentations range from meningitis to encephalitis with or without myelitis, and infection may result in death or long-term neurological sequelae. TBE is endemic in regions of at least 27 European as well as in some Asian countries. Infection and disease, however, can be averted successfully by tick-bite prevention and active vaccination. The risk of infection has shifted from daily life and occupational exposure to leisure-time activities, including travelling. Outdoor activities during the tick season with contact with nature increase the risk of tick bites. Although the number of travel-associated cases is unknown, it is certainly under-estimated because there is hardly any awareness of TBE in non-endemic countries. Therefore, the majority of cases remain undiagnosed, also because of the lack of diagnostic serology, as there is no routine screening for TBE in non-endemic regions. Because of the increasing number of travellers from TBE non-endemic to endemic regions, and in view of the fact that TBE was included in the list of notifiable diseases in the European Union in September 2012, this disease needs to become an important issue in travel medicine. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Quantification of vector and host competence for Japanese encephalitis virus: a systematic review of the literature

    Science.gov (United States)

    Japanese encephalitis virus (JEV) is a virus of the Flavivirus genus that may result in encephalitis in human hosts. This vector-borne zoonosis occurs in Eastern and Southeastern Asia and an intentional or inadvertent introduction into the United States (US) will have major public health and economi...

  2. Laboratory containment practices for arthropod vectors of human and animal pathogens.

    Science.gov (United States)

    Tabachnick, Walter J

    2006-03-01

    Arthropod-borne pathogens have an impact on the health and well-being of humans and animals throughout the world. Research involving arthropod vectors of disease is often dependent on the ability to maintain the specific arthropod species in laboratory colonies. The author reviews current arthropod containment practices and discusses their importance from public health and ecological perspectives.

  3. Optimization of formulation and delivery technology of entomopathogenic fungi for malaria vector control

    NARCIS (Netherlands)

    Mnyone, L.L.

    2010-01-01

    Vector control is one of the most effective means of controlling mosquito-borne diseases such as malaria. The broad goal of this strategy is to protect individuals against infective mosquito bites and, at the community level, to reduce the intensity of disease transmission. With the deployment of

  4. Mosquitoes and Culicoides biting midges: vector range and the influence of climate change

    NARCIS (Netherlands)

    Elbers, A.R.W.; Koenraadt, C.J.M.; Meiswinkel, R.

    2015-01-01

    Vector-borne animal diseases pose a continuous and substantial threat to livestock economies around the globe. Increasing international travel, the globalisation of trade, and climate change are likely to play a progressively more important role in the introduction, establishment and spread of

  5. A gravity model for the spread of a pollinator-borne plant pathogen.

    Science.gov (United States)

    Ferrari, Matthew J; Bjørnstad, Ottar N; Partain, Jessica L; Antonovics, Janis

    2006-09-01

    Many pathogens of plants are transmitted by arthropod vectors whose movement between individual hosts is influenced by foraging behavior. Insect foraging has been shown to depend on both the quality of hosts and the distances between hosts. Given the spatial distribution of host plants and individual variation in quality, vector foraging patterns may therefore produce predictable variation in exposure to pathogens. We develop a "gravity" model to describe the spatial spread of a vector-borne plant pathogen from underlying models of insect foraging in response to host quality using the pollinator-borne smut fungus Microbotryum violaceum as a case study. We fit the model to spatially explicit time series of M. violaceum transmission in replicate experimental plots of the white campion Silene latifolia. The gravity model provides a better fit than a mean field model or a model with only distance-dependent transmission. The results highlight the importance of active vector foraging in generating spatial patterns of disease incidence and for pathogen-mediated selection for floral traits.

  6. A Performance Management Initiative for Local Health Department Vector Control Programs.

    Science.gov (United States)

    Gerding, Justin; Kirshy, Micaela; Moran, John W; Bialek, Ron; Lamers, Vanessa; Sarisky, John

    2016-01-01

    Local health department (LHD) vector control programs have experienced reductions in funding and capacity. Acknowledging this situation and its potential effect on the ability to respond to vector-borne diseases, the U.S. Centers for Disease Control and Prevention and the Public Health Foundation partnered on a performance management initiative for LHD vector control programs. The initiative involved 14 programs that conducted a performance assessment using the Environmental Public Health Performance Standards. The programs, assisted by quality improvement (QI) experts, used the assessment results to prioritize improvement areas that were addressed with QI projects intended to increase effectiveness and efficiency in the delivery of services such as responding to mosquito complaints and educating the public about vector-borne disease prevention. This article describes the initiative as a process LHD vector control programs may adapt to meet their performance management needs. This study also reviews aggregate performance assessment results and QI projects, which may reveal common aspects of LHD vector control program performance and priority improvement areas. LHD vector control programs interested in performance assessment and improvement may benefit from engaging in an approach similar to this performance management initiative.

  7. Hierarchal scalar and vector tetrahedra

    International Nuclear Information System (INIS)

    Webb, J.P.; Forghani, B.

    1993-01-01

    A new set of scalar and vector tetrahedral finite elements are presented. The elements are hierarchal, allowing mixing of polynomial orders; scalar orders up to 3 and vector orders up to 2 are defined. The vector elements impose tangential continuity on the field but not normal continuity, making them suitable for representing the vector electric or magnetic field. Further, the scalar and vector elements are such that they can easily be used in the same mesh, a requirement of many quasi-static formulations. Results are presented for two 50 Hz problems: the Bath Cube, and TEAM Problem 7

  8. Leishmaniasis vector behaviour in Kenya

    International Nuclear Information System (INIS)

    Mutinga, M.J.

    1980-01-01

    Leishmaniasis in Kenya exists in two forms: cutaneous and visceral. The vectors of visceral leishmaniasis have been the subject of investigation by various researchers since World War II, when the outbreak of the disease was first noticed. The vectors of cutaneous leishmaniasis were first worked on only a decade ago after the discovery of the disease focus in Mt. Elgon. The vector behaviour of these diseases, namely Phlebotomus pedifer, the vector of cutaneous leishmaniasis, and Phlebotomus martini, the vector of visceral leishmaniasis, are discussed in detail. P. pedifer has been found to breed and bite inside caves, whereas P. martini mainly bites inside houses. (author)

  9. Comparative genomics shows that viral integrations are abundant and express piRNAs in the arboviral vectors Aedes aegypti and Aedes albopictus

    NARCIS (Netherlands)

    Palatini, U.; Miesen, P.; Carballar-Lejarazu, R.; Ometto, L.; Rizzo, E.; Tu, Z.; Rij, R.P. van; Bonizzoni, M.

    2017-01-01

    BACKGROUND: Arthropod-borne viruses (arboviruses) transmitted by mosquito vectors cause many important emerging or resurging infectious diseases in humans including dengue, chikungunya and Zika. Understanding the co-evolutionary processes among viruses and vectors is essential for the development of

  10. Towards the genetic manipulation of mosquito disease vectors

    International Nuclear Information System (INIS)

    Crampton, J.M.; Lycett, G.J.; Warren, A.

    1998-01-01

    Our research is aimed at developing the technologies necessary to undertake the genetic manipulation of insect vector genomes. In the longer term, we wish to explore the potential that this technology may have for developing novel strategies for the control of vector-borne diseases. The focus of our current research has been to: i) identify and characterise endogenous transposable elements in the genomes of mosquito vectors -research has focussed on identifying both Class I and Class 11 elements and determining their structure and distribution within mosquito genomes; ii) develop and use transfection systems for mosquito cells in culture as a test bed for transformation vectors and promoters - transfection techniques, vector constructs and different promoters driving reporter genes have been utilised to optimise the transformation of both Aedes aegypti and Anopheles gambiae cells in culture; iii) identify putative promoter sequences which are induced in the female mosquito midgut when it takes a blood meal - the Anopheles gambiae trypsin gene locus has been cloned and sequenced and the intergenic regions assessed for their ability to induce reporter gene expression in mosquito gut cells. The progress we have made in each of these areas will be described and discussed in the context of our longer term aim which is to introduce genes coding for antiparasitic agents into mosquito genomes in such a way that they are expressed in the mosquito midgut and disrupt transmission of the malaria parasite. (author)

  11. Towards the genetic manipulation of mosquito disease vectors

    Energy Technology Data Exchange (ETDEWEB)

    Crampton, J M; Lycett, G J; Warren, A [Division of Molecular Biology and Immunology, Liverpool School of Tropical Medicine, Liverpool (United Kingdom)

    1998-01-01

    Our research is aimed at developing the technologies necessary to undertake the genetic manipulation of insect vector genomes. In the longer term, we wish to explore the potential that this technology may have for developing novel strategies for the control of vector-borne diseases. The focus of our current research has been to: i) identify and characterise endogenous transposable elements in the genomes of mosquito vectors -research has focussed on identifying both Class I and Class 11 elements and determining their structure and distribution within mosquito genomes; ii) develop and use transfection systems for mosquito cells in culture as a test bed for transformation vectors and promoters - transfection techniques, vector constructs and different promoters driving reporter genes have been utilised to optimise the transformation of both Aedes aegypti and Anopheles gambiae cells in culture; iii) identify putative promoter sequences which are induced in the female mosquito midgut when it takes a blood meal - the Anopheles gambiae trypsin gene locus has been cloned and sequenced and the intergenic regions assessed for their ability to induce reporter gene expression in mosquito gut cells. The progress we have made in each of these areas will be described and discussed in the context of our longer term aim which is to introduce genes coding for antiparasitic agents into mosquito genomes in such a way that they are expressed in the mosquito midgut and disrupt transmission of the malaria parasite. (author). 41 refs, 2 figs.

  12. Insect vectors of Leishmania: distribution, physiology and their control.

    Science.gov (United States)

    Sharma, Umakant; Singh, Sarman

    2008-12-01

    Leishmaniasis is a deadly vector-borne disease that causes significant morbidity and mortality in Africa, Asia, Latin America and Mediterranean regions. The causative agent of leishmaniasis is transmitted from man to man by a tiny insect called sandfly. Approximately, 600 species of sandflies are known but only 10% of these act as disease vectors. Further, only 30 species of these are important from public health point. Fauna of Indian sub-zone is represented by 46 species, of these, 11 belong to Phlebotomine species and 35 to Sergentomyia species. Phlebotomus argentipes is the proven vector of kala-azar or visceral leishmaniasis in India. This review gives an insight into the insect vectors of human leishmaniasis, their geographical distribution, recent taxonomic classification, habitat, and different control measures including indoor residual spraying (IRS), insecticide-treated bednets (ITNs), environmental management, biological control, and emerging resistance to DDT. Role of satellite remote sensing for early prediction of the disease by identifying the sandflygenic conditions cannot be undermined. The article also underlines the importance of synthetic pheromones which can be used in near future for the control of these vectors.

  13. Validation of Born Traveltime Kernels

    Science.gov (United States)

    Baig, A. M.; Dahlen, F. A.; Hung, S.

    2001-12-01

    Most inversions for Earth structure using seismic traveltimes rely on linear ray theory to translate observed traveltime anomalies into seismic velocity anomalies distributed throughout the mantle. However, ray theory is not an appropriate tool to use when velocity anomalies have scale lengths less than the width of the Fresnel zone. In the presence of these structures, we need to turn to a scattering theory in order to adequately describe all of the features observed in the waveform. By coupling the Born approximation to ray theory, the first order dependence of heterogeneity on the cross-correlated traveltimes (described by the Fréchet derivative or, more colourfully, the banana-doughnut kernel) may be determined. To determine for what range of parameters these banana-doughnut kernels outperform linear ray theory, we generate several random media specified by their statistical properties, namely the RMS slowness perturbation and the scale length of the heterogeneity. Acoustic waves are numerically generated from a point source using a 3-D pseudo-spectral wave propagation code. These waves are then recorded at a variety of propagation distances from the source introducing a third parameter to the problem: the number of wavelengths traversed by the wave. When all of the heterogeneity has scale lengths larger than the width of the Fresnel zone, ray theory does as good a job at predicting the cross-correlated traveltime as the banana-doughnut kernels do. Below this limit, wavefront healing becomes a significant effect and ray theory ceases to be effective even though the kernels remain relatively accurate provided the heterogeneity is weak. The study of wave propagation in random media is of a more general interest and we will also show our measurements of the velocity shift and the variance of traveltime compare to various theoretical predictions in a given regime.

  14. Vector population growth and condition-dependent movement drive the spread of plant pathogens.

    Science.gov (United States)

    Shaw, Allison K; Peace, Angela; Power, Alison G; Bosque-Pérez, Nilsa A

    2017-08-01

    Plant viruses, often spread by arthropod vectors, impact natural and agricultural ecosystems worldwide. Intuitively, the movement behavior and life history of vectors influence pathogen spread, but the relative contribution of each factor has not been examined. Recent research has highlighted the influence of host infection status on vector behavior and life history. Here, we developed a model to explore how vector traits influence the spread of vector-borne plant viruses. We allowed vector life history (growth rate, carrying capacity) and movement behavior (departure and settlement rates) parameters to be conditional on whether the plant host is infected or healthy and whether the vector is viruliferous (carrying the virus) or not. We ran simulations under a wide range of parameter combinations and quantified the fraction of hosts infected over time. We also ran case studies of the model for Barley yellow dwarf virus, a persistently transmitted virus, and for Potato virus Y, a non-persistently transmitted virus. We quantified the relative importance of each parameter on pathogen spread using Latin hypercube sampling with the statistical partial rank correlation coefficient technique. We found two general types of mechanisms in our model that increased the rate of pathogen spread. First, increasing factors such as vector intrinsic growth rate, carrying capacity, and departure rate from hosts (independent of whether these factors were condition-dependent) led to more vectors moving between hosts, which increased pathogen spread. Second, changing condition-dependent factors such as a vector's preference for settling on a host with a different infection status than itself, and vector tendency to leave a host of the same infection status, led to increased contact between hosts and vectors with different infection statuses, which also increased pathogen spread. Overall, our findings suggest that vector population growth rates had the greatest influence on rates of virus

  15. Prevention of vector transmitted diseases with clove oil insect repellent.

    Science.gov (United States)

    Shapiro, Rochel

    2012-08-01

    Vector repellent is one element in the prevention of vector-borne diseases. Families that neglect protecting their children against vectors risk their children contracting illnesses such as West Nile virus, eastern equine encephalitis, Lyme disease, malaria, dengue hemorrhagic fever, yellow fever, babesiosis, Crimean-Congo hemorrhagic fever, Rocky Mountain spotted fever, Southern tick-associated rash illness, ehrlichiosis, tick-borne relapsing fever, tularemia, and other insect and arthropod related diseases (CDC, 2011). Identification of families at risk includes screening of the underlying basis for reluctance to apply insect repellent. Nurses and physicians can participate in a positive role by assisting families to determine the proper prophylaxis by recommending insect repellent choices that are economical, safe, and easy to use. A holistic alternative might include the suggestion of clove oil in cases where families might have trepidations regarding the use of DEET on children. This article will explore the safety and effectiveness of clove oil and its use as an insect repellent. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Physical Fitness in Young Adults Born Preterm.

    Science.gov (United States)

    Tikanmäki, Marjaana; Tammelin, Tuija; Sipola-Leppänen, Marika; Kaseva, Nina; Matinolli, Hanna-Maria; Miettola, Satu; Eriksson, Johan G; Järvelin, Marjo-Riitta; Vääräsmäki, Marja; Kajantie, Eero

    2016-01-01

    Young adults born preterm have higher levels of cardiometabolic risk factors than their term-born peers. Muscular and cardiorespiratory fitness have important cardiometabolic and other health benefits. We assessed muscular, cardiorespiratory, and self-rated fitness in preterm-born young adults. We studied unimpaired participants of the ESTER (Ennenaikainen syntymä ja aikuisiän terveys [Preterm Birth and Early-Life Programming of Adult Health and Disease]) birth cohort study at age 23.3 (SD: 1.2) years: 139 born early preterm (EPT; Young adults born EPT (-0.8; 95% confidence interval: -1.5 to -0.1; adjusted for gender, age, and source cohort) and LPT (-0.8; -1.4 to -0.3) performed fewer modified push-ups than controls. Handgrip strength was 23.8 (0.9-46.8) N lower in EPT participants. Cardiorespiratory fitness, measured by submaximal step test, was similar. On a self-rated fitness scale (1-5), the EPT adults reported 0.2 (0.0-0.4) lower scores than controls. After adjustment for early-life confounders, the results remained. They attenuated after further adjustment for mediating factors. Young adults born EPT and LPT had lower muscular fitness than controls, which may predispose them to cardiometabolic and other chronic diseases. Adults born EPT also perceived themselves as less fit than controls. Copyright © 2016 by the American Academy of Pediatrics.

  17. Scalar and vector Galileons

    International Nuclear Information System (INIS)

    Rodríguez, Yeinzon; Navarro, Andrés A.

    2017-01-01

    An alternative for the construction of fundamental theories is the introduction of Galileons. These are fields whose action leads to non higher than second-order equations of motion. As this is a necessary but not sufficient condition to make the Hamiltonian bounded from below, as long as the action is not degenerate, the Galileon construction is a way to avoid pathologies both at the classical and quantum levels. Galileon actions are, therefore, of great interest in many branches of physics, specially in high energy physics and cosmology. This proceedings contribution presents the generalities of the construction of both scalar and vector Galileons following two different but complimentary routes. (paper)

  18. Vectors to success

    International Nuclear Information System (INIS)

    Otsason, J.

    1998-01-01

    The Vector Pipeline project linking the Chicago supply hub to markets in eastern Canada, the northeastern U.S. and the Mid-Atlantic states, is described. Subsidiary objectives of the promoters are to match market timing to upstream pipelines and market requirements, and to provide low cost expandability to complement upstream expandability. The presentation includes description of the project, costs, leased facilities, rates and tariffs, right of way considerations, storage facilities and a project schedule. Construction is to begin in March 1999 and the line should be in service in November 1999

  19. Analytic calculation of finite-population reproductive numbers for direct- and vector-transmitted diseases with homogeneous mixing.

    Science.gov (United States)

    Keegan, Lindsay; Dushoff, Jonathan

    2014-05-01

    The basic reproductive number, R0, provides a foundation for evaluating how various factors affect the incidence of infectious diseases. Recently, it has been suggested that, particularly for vector-transmitted diseases, R0 should be modified to account for the effects of finite host population within a single disease transmission generation. Here, we use a transmission factor approach to calculate such "finite-population reproductive numbers," under the assumption of homogeneous mixing, for both vector-borne and directly transmitted diseases. In the case of vector-borne diseases, we estimate finite-population reproductive numbers for both host-to-host and vector-to-vector generations, assuming that the vector population is effectively infinite. We find simple, interpretable formulas for all three of these quantities. In the direct case, we find that finite-population reproductive numbers diverge from R0 before R0 reaches half of the population size. In the vector-transmitted case, we find that the host-to-host number diverges at even lower values of R0, while the vector-to-vector number diverges very little over realistic parameter ranges.

  20. Bioelectrical impedance vector distribution in the first year of life.

    Science.gov (United States)

    Savino, Francesco; Grasso, Giulia; Cresi, Francesco; Oggero, Roberto; Silvestro, Leandra

    2003-06-01

    We assessed the bioelectrical impedance vector distribution in a sample of healthy infants in the first year of life, which is not available in literature. The study was conducted as a cross-sectional study in 153 healthy Caucasian infants (90 male and 63 female) younger than 1 y, born at full term, adequate for gestational age, free from chronic diseases or growth problems, and not feverish. Z scores for weight, length, cranial circumference, and body mass index for the study population were within the range of +/-1.5 standard deviations according to the Euro-Growth Study references. Concurrent anthropometrics (weight, length, and cranial circumference), body mass index, and bioelectrical impedance (resistance and reactance) measurements were made by the same operator. Whole-body (hand to foot) tetrapolar measurements were performed with a single-frequency (50 kHz), phase-sensitive impedance analyzer. The study population was subdivided into three classes of age for statistical analysis: 0 to 3.99 mo, 4 to 7.99 mo, and 8 to 11.99 mo. Using the bivariate normal distribution of resistance and reactance components standardized by the infant's length, the bivariate 95% confidence limits for the mean impedance vector separated by sex and age groups were calculated and plotted. Further, the bivariate 95%, 75%, and 50% tolerance intervals for individual vector measurements in the first year of life were plotted. Resistance and reactance values often fluctuated during the first year of life, particularly as raw measurements (without normalization by subject's length). However, 95% confidence ellipses of mean vectors from the three age groups overlapped each other, as did confidence ellipses by sex for each age class, indicating no significant vector migration during the first year of life. We obtained an estimate of mean impedance vector in a sample of healthy infants in the first year of life and calculated the bivariate values for an individual vector (95%, 75%, and 50

  1. Vector-vector production in photon-photon interactions

    International Nuclear Information System (INIS)

    Ronan, M.T.

    1988-01-01

    Measurements of exclusive untagged /rho/ 0 /rho/ 0 , /rho//phi/, K/sup *//bar K//sup */, and /rho/ω production and tagged /rho/ 0 /rho/ 0 production in photon-photon interactions by the TPC/Two-Gamma experiment are reviewed. Comparisons to the results of other experiments and to models of vector-vector production are made. Fits to the data following a four quark model prescription for vector meson pair production are also presented. 10 refs., 9 figs

  2. Vertical vector face lift.

    Science.gov (United States)

    Somoano, Brian; Chan, Joanna; Morganroth, Greg

    2011-01-01

    Facial rejuvenation using local anesthesia has evolved in the past decade as a safer option for patients seeking fewer complications and minimal downtime. Mini- and short-scar face lifts using more conservative incision lengths and extent of undermining can be effective in the younger patient with lower face laxity and minimal loose, elastotic neck skin. By incorporating both an anterior and posterior approach and using an incision length between the mini and more traditional face lift, the Vertical Vector Face Lift can achieve longer-lasting and natural results with lesser cost and risk. Submentoplasty and liposuction of the neck and jawline, fundamental components of the vertical vector face lift, act synergistically with superficial musculoaponeurotic system plication to reestablish a more youthful, sculpted cervicomental angle, even in patients with prominent jowls. Dramatic results can be achieved in the right patient by combining with other procedures such as injectable fillers, chin implants, laser resurfacing, or upper and lower blepharoplasties. © 2011 Wiley Periodicals, Inc.

  3. Vector control in leishmaniasis.

    Science.gov (United States)

    Kishore, K; Kumar, V; Kesari, S; Dinesh, D S; Kumar, A J; Das, P; Bhattacharya, S K

    2006-03-01

    Indoor residual spraying is a simple and cost effective method of controlling endophilic vectors and DDT remains the insecticide of choice for the control of leishmaniasis. However resistance to insecticide is likely to become more widespread in the population especially in those areas in which insecticide has been used for years. In this context use of slow release emulsified suspension (SRES) may be the best substitute. In this review spraying frequencies of DDT and new schedule of spray have been discussed. Role of biological control and environment management in the control of leishmaniasis has been emphasized. Allethrin (coil) 0.1 and 1.6 per cent prallethrin (liquid) have been found to be effective repellents against Phlebotomus argentipes, the vector of Indian kalaazar. Insecticide impregnated bednets is another area which requires further research on priority basis for the control of leishmaniasis. Role of satellite remote sensing for early prediction of disease by identifying the sandflygenic conditions cannot be undermined. In future synthetic pheromons can be exploited in the control of leishmaniasis.

  4. Advancing vector biology research: a community survey for future directions, research applications and infrastructure requirements

    Science.gov (United States)

    Kohl, Alain; Pondeville, Emilie; Schnettler, Esther; Crisanti, Andrea; Supparo, Clelia; Christophides, George K.; Kersey, Paul J.; Maslen, Gareth L.; Takken, Willem; Koenraadt, Constantianus J. M.; Oliva, Clelia F.; Busquets, Núria; Abad, F. Xavier; Failloux, Anna-Bella; Levashina, Elena A.; Wilson, Anthony J.; Veronesi, Eva; Pichard, Maëlle; Arnaud Marsh, Sarah; Simard, Frédéric; Vernick, Kenneth D.

    2016-01-01

    Vector-borne pathogens impact public health, animal production, and animal welfare. Research on arthropod vectors such as mosquitoes, ticks, sandflies, and midges which transmit pathogens to humans and economically important animals is crucial for development of new control measures that target transmission by the vector. While insecticides are an important part of this arsenal, appearance of resistance mechanisms is increasingly common. Novel tools for genetic manipulation of vectors, use of Wolbachia endosymbiotic bacteria, and other biological control mechanisms to prevent pathogen transmission have led to promising new intervention strategies, adding to strong interest in vector biology and genetics as well as vector–pathogen interactions. Vector research is therefore at a crucial juncture, and strategic decisions on future research directions and research infrastructure investment should be informed by the research community. A survey initiated by the European Horizon 2020 INFRAVEC-2 consortium set out to canvass priorities in the vector biology research community and to determine key activities that are needed for researchers to efficiently study vectors, vector-pathogen interactions, as well as access the structures and services that allow such activities to be carried out. We summarize the most important findings of the survey which in particular reflect the priorities of researchers in European countries, and which will be of use to stakeholders that include researchers, government, and research organizations. PMID:27677378

  5. Experimental demonstration of vector E x vector B plasma divertor

    International Nuclear Information System (INIS)

    Strait, E.J.; Kerst, D.W.; Sprott, J.C.

    1977-01-01

    The vector E x vector B drift due to an applied radial electric field in a tokamak with poloidal divertor can speed the flow of plasma out of the scrape-off region, and provide a means of externally controlling the flow rate and thus the width of the density fall-off. An experiment in the Wisconsin levitated toroidal octupole, using vector E x vector B drifts alone, demonstrates divertor-like behavior, including 70% reduction of plasma density near the wall and 40% reduction of plasma flux to the wall, with no adverse effects on confinement of the main plasma

  6. How effective is integrated vector management against malaria and lymphatic filariasis where the diseases are transmitted by the same vector?

    Directory of Open Access Journals (Sweden)

    Christopher M Stone

    2014-12-01

    Full Text Available The opportunity to integrate vector management across multiple vector-borne diseases is particularly plausible for malaria and lymphatic filariasis (LF control where both diseases are transmitted by the same vector. To date most examples of integrated control targeting these diseases have been unanticipated consequences of malaria vector control, rather than planned strategies that aim to maximize the efficacy and take the complex ecological and biological interactions between the two diseases into account.We developed a general model of malaria and LF transmission and derived expressions for the basic reproductive number (R0 for each disease. Transmission of both diseases was most sensitive to vector mortality and biting rate. Simulating different levels of coverage of long lasting-insecticidal nets (LLINs and larval control confirms the effectiveness of these interventions for the control of both diseases. When LF was maintained near the critical density of mosquitoes, minor levels of vector control (8% coverage of LLINs or treatment of 20% of larval sites were sufficient to eliminate the disease. Malaria had a far greater R0 and required a 90% population coverage of LLINs in order to eliminate it. When the mosquito density was doubled, 36% and 58% coverage of LLINs and larval control, respectively, were required for LF elimination; and malaria elimination was possible with a combined coverage of 78% of LLINs and larval control.Despite the low level of vector control required to eliminate LF, simulations suggest that prevalence of LF will decrease at a slower rate than malaria, even at high levels of coverage. If representative of field situations, integrated management should take into account not only how malaria control can facilitate filariasis elimination, but strike a balance between the high levels of coverage of (multiple interventions required for malaria with the long duration predicted to be required for filariasis elimination.

  7. How effective is integrated vector management against malaria and lymphatic filariasis where the diseases are transmitted by the same vector?

    Science.gov (United States)

    Stone, Christopher M; Lindsay, Steve W; Chitnis, Nakul

    2014-12-01

    The opportunity to integrate vector management across multiple vector-borne diseases is particularly plausible for malaria and lymphatic filariasis (LF) control where both diseases are transmitted by the same vector. To date most examples of integrated control targeting these diseases have been unanticipated consequences of malaria vector control, rather than planned strategies that aim to maximize the efficacy and take the complex ecological and biological interactions between the two diseases into account. We developed a general model of malaria and LF transmission and derived expressions for the basic reproductive number (R0) for each disease. Transmission of both diseases was most sensitive to vector mortality and biting rate. Simulating different levels of coverage of long lasting-insecticidal nets (LLINs) and larval control confirms the effectiveness of these interventions for the control of both diseases. When LF was maintained near the critical density of mosquitoes, minor levels of vector control (8% coverage of LLINs or treatment of 20% of larval sites) were sufficient to eliminate the disease. Malaria had a far greater R0 and required a 90% population coverage of LLINs in order to eliminate it. When the mosquito density was doubled, 36% and 58% coverage of LLINs and larval control, respectively, were required for LF elimination; and malaria elimination was possible with a combined coverage of 78% of LLINs and larval control. Despite the low level of vector control required to eliminate LF, simulations suggest that prevalence of LF will decrease at a slower rate than malaria, even at high levels of coverage. If representative of field situations, integrated management should take into account not only how malaria control can facilitate filariasis elimination, but strike a balance between the high levels of coverage of (multiple) interventions required for malaria with the long duration predicted to be required for filariasis elimination.

  8. Structure-borne noise at hotels

    Science.gov (United States)

    Wilson, George Paul; Jue, Deborah A.

    2002-11-01

    Hotels present a challenging environment for building designers to provide suitable noise and vibration isolation between very incompatible uses. While many are familiar with ways to reduce traditional sources of airborne noise and vibration, structure-borne noise and vibration are often overlooked, often with costly repercussions. Structure-borne noise can be very difficult to pinpoint, and troubleshooting the sources of the vibration can be a tedious process. Therefore, the best approach is to avoid the problem altogether during design, with attention to the building construction, potential vibration sources, building uses and equipment locations. In this paper, the relationship between structure-borne vibration and noise are reviewed, typical vibration sources discussed (e.g., aerobic rooms, laundry rooms, mechanical equipment/building services, and subway rail transit), and key details and design guidance to minimize structure-borne noise provided.

  9. On Born approximation in black hole scattering

    Science.gov (United States)

    Batic, D.; Kelkar, N. G.; Nowakowski, M.

    2011-12-01

    A massless field propagating on spherically symmetric black hole metrics such as the Schwarzschild, Reissner-Nordström and Reissner-Nordström-de Sitter backgrounds is considered. In particular, explicit formulae in terms of transcendental functions for the scattering of massless scalar particles off black holes are derived within a Born approximation. It is shown that the conditions on the existence of the Born integral forbid a straightforward extraction of the quasi normal modes using the Born approximation for the scattering amplitude. Such a method has been used in literature. We suggest a novel, well defined method, to extract the large imaginary part of quasinormal modes via the Coulomb-like phase shift. Furthermore, we compare the numerically evaluated exact scattering amplitude with the Born one to find that the approximation is not very useful for the scattering of massless scalar, electromagnetic as well as gravitational waves from black holes.

  10. Video Vectorization via Tetrahedral Remeshing.

    Science.gov (United States)

    Wang, Chuan; Zhu, Jie; Guo, Yanwen; Wang, Wenping

    2017-02-09

    We present a video vectorization method that generates a video in vector representation from an input video in raster representation. A vector-based video representation offers the benefits of vector graphics, such as compactness and scalability. The vector video we generate is represented by a simplified tetrahedral control mesh over the spatial-temporal video volume, with color attributes defined at the mesh vertices. We present novel techniques for simplification and subdivision of a tetrahedral mesh to achieve high simplification ratio while preserving features and ensuring color fidelity. From an input raster video, our method is capable of generating a compact video in vector representation that allows a faithful reconstruction with low reconstruction errors.

  11. Hyperbolic-symmetry vector fields.

    Science.gov (United States)

    Gao, Xu-Zhen; Pan, Yue; Cai, Meng-Qiang; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

    2015-12-14

    We present and construct a new kind of orthogonal coordinate system, hyperbolic coordinate system. We present and design a new kind of local linearly polarized vector fields, which is defined as the hyperbolic-symmetry vector fields because the points with the same polarization form a series of hyperbolae. We experimentally demonstrate the generation of such a kind of hyperbolic-symmetry vector optical fields. In particular, we also study the modified hyperbolic-symmetry vector optical fields with the twofold and fourfold symmetric states of polarization when introducing the mirror symmetry. The tight focusing behaviors of these vector fields are also investigated. In addition, we also fabricate micro-structures on the K9 glass surfaces by several tightly focused (modified) hyperbolic-symmetry vector fields patterns, which demonstrate that the simulated tightly focused fields are in good agreement with the fabricated micro-structures.

  12. Extended vector-tensor theories

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Rampei; Naruko, Atsushi; Yoshida, Daisuke, E-mail: rampei@th.phys.titech.ac.jp, E-mail: naruko@th.phys.titech.ac.jp, E-mail: yoshida@th.phys.titech.ac.jp [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

    2017-01-01

    Recently, several extensions of massive vector theory in curved space-time have been proposed in many literatures. In this paper, we consider the most general vector-tensor theories that contain up to two derivatives with respect to metric and vector field. By imposing a degeneracy condition of the Lagrangian in the context of ADM decomposition of space-time to eliminate an unwanted mode, we construct a new class of massive vector theories where five degrees of freedom can propagate, corresponding to three for massive vector modes and two for massless tensor modes. We find that the generalized Proca and the beyond generalized Proca theories up to the quartic Lagrangian, which should be included in this formulation, are degenerate theories even in curved space-time. Finally, introducing new metric and vector field transformations, we investigate the properties of thus obtained theories under such transformations.

  13. Pap Tests and Foreign-Born Women

    Centers for Disease Control (CDC) Podcasts

    Foreign-born women living in the U.S. are less likely to have Pap tests to detect cervical cancer than women born in this country. The problem is worse for women from certain countries or regions. Find out why this is a disturbing trend, who these women are and why they are less likely to get a Pap test, and what CDC is doing about it.

  14. Optimality Conditions in Vector Optimization

    CERN Document Server

    Jiménez, Manuel Arana; Lizana, Antonio Rufián

    2011-01-01

    Vector optimization is continuously needed in several science fields, particularly in economy, business, engineering, physics and mathematics. The evolution of these fields depends, in part, on the improvements in vector optimization in mathematical programming. The aim of this Ebook is to present the latest developments in vector optimization. The contributions have been written by some of the most eminent researchers in this field of mathematical programming. The Ebook is considered essential for researchers and students in this field.

  15. Symmetric vectors and algebraic classification

    International Nuclear Information System (INIS)

    Leibowitz, E.

    1980-01-01

    The concept of symmetric vector field in Riemannian manifolds, which arises in the study of relativistic cosmological models, is analyzed. Symmetric vectors are tied up with the algebraic properties of the manifold curvature. A procedure for generating a congruence of symmetric fields out of a given pair is outlined. The case of a three-dimensional manifold of constant curvature (''isotropic universe'') is studied in detail, with all its symmetric vector fields being explicitly constructed

  16. Foreign-born Peers and Academic Performance.

    Science.gov (United States)

    Conger, Dylan

    2015-04-01

    The academic performance of foreign-born youth in the United States is well studied, yet little is known about whether and how foreign-born students influence their classmates. In this article, I develop a set of expectations regarding the potential consequences of immigrant integration across schools, with a distinction between the effects of sharing schools with immigrants who are designated as English language learners (ELL) and those who are not. I then use administrative data on multiple cohorts of Florida public high school students to estimate the effect of immigrant shares on immigrant and native-born students' academic performance. The identification strategy pays careful attention to the selection problem by estimating the effect of foreign-born peers from deviations in the share foreign-born across cohorts of students attending the same school in different years. The assumption underlying this approach is that students choose schools based on the composition of the entire school, not on the composition of each entering cohort. The results of the analysis, which hold under several robustness checks, indicate that foreign-born peers (both those who are ELL and those who are non-ELL) have no effect on their high school classmates' academic performance.

  17. Vector continued fractions using a generalized inverse

    International Nuclear Information System (INIS)

    Haydock, Roger; Nex, C M M; Wexler, Geoffrey

    2004-01-01

    A real vector space combined with an inverse (involution) for vectors is sufficient to define a vector continued fraction whose parameters consist of vector shifts and changes of scale. The choice of sign for different components of the vector inverse permits construction of vector analogues of the Jacobi continued fraction. These vector Jacobi fractions are related to vector and scalar-valued polynomial functions of the vectors, which satisfy recurrence relations similar to those of orthogonal polynomials. The vector Jacobi fraction has strong convergence properties which are demonstrated analytically, and illustrated numerically

  18. Climate Change and Vector-borne Diseases: An Economic Impact Analysis of Malaria in Africa

    Directory of Open Access Journals (Sweden)

    Ximing Wu

    2011-03-01

    Full Text Available A semi-parametric econometric model is used to study the relationship between malaria cases and climatic factors in 25 African countries. Results show that a marginal change in temperature and precipitation levels would lead to a significant change in the number of malaria cases for most countries by the end of the century. Consistent with the existing biophysical malaria model results, the projected effects of climate change are mixed. Our model projects that some countries will see an increase in malaria cases but others will see a decrease. We estimate projected malaria inpatient and outpatient treatment costs as a proportion of annual 2000 health expenditures per 1,000 people. We found that even under minimal climate change scenario, some countries may see their inpatient treatment cost of malaria increase more than 20%.

  19. Operational Mosquito and Vector-Borne Diseases Surveillance at Incirlik Air Base, Turkey

    Science.gov (United States)

    2017-05-23

    of Biological Diversity , Columbus, OH, or the - cies and tested for arboviruses. Pools ranged from 1-25 mosquitoes depending on submission numbers...Rickettsia felis (Rickett- - phonaptera: Pulicidae) in the Philippines . J Ento- mol Sci. 2012;47:95-96. Mosquito surveillance data from Incirlik Air Base...Taylor SJ, Durden LA, Foley EH, Reeves WK. The bat tick Carios azteci (Acari: Argasidae) from Be- lize, with an endosymbiotic Coxiellaceae. Speleo

  20. Microclimatic temperatures increase the potential for vector-borne disease transmission in the Scandinavian climate

    DEFF Research Database (Denmark)

    Haider, Najmul; Kirkeby, Carsten Thure; Kristensen, Birgit

    2017-01-01

    We quantified the difference between the meteorological temperature recorded by the Danish Meteorological Institute (DMI) weather stations and the actual microclimatic temperatures at two or three different heights at six potential insect habitats. We then compared the impact of the hourly temper...

  1. Social exclusion modifies climate and deforestation impacts on a vector-borne disease.

    Science.gov (United States)

    Chaves, Luis Fernando; Cohen, Justin M; Pascual, Mercedes; Wilson, Mark L

    2008-02-06

    The emergence of American Cutaneous Leishmaniasis (ACL) has been associated with changes in the relationship between people and forests, leading to the view that forest ecosystems increase infection risk and subsequent proposal that deforestation could reduce re-emergence of this disease. We analyzed county-level incidence rates of ACL in Costa Rica (1996-2000) as a function of social and environmental variables relevant to transmission ecology with statistical models that incorporate breakpoints. Once social marginality was taken into account, the effect of living close to a forest on infection risk was small, and diminished exponentially above a breakpoint. Forest cover was associated with the modulation of temporal effects of El Niño Southern Oscillation (ENSO) at small spatial scales, revealing an additional complex interplay of environmental forces and disease patterns. Social factors, which previously have not been evaluated rigorously together with environmental and climatic factors, appear to play a critical role that may ultimately determine disease risk.

  2. Strain improvement of fungal insecticides for controlling insect pests and vector-borne diseases.

    Science.gov (United States)

    Fang, Weiguo; Azimzadeh, Philippe; St Leger, Raymond J

    2012-06-01

    Insect pathogenic fungi play an important natural role in controlling insect pests. However, few have been successfully commercialized due to low virulence and sensitivity to abiotic stresses that produce inconsistent results in field applications. These limitations are inherent in most naturally occurring biological control agents but development of recombinant DNA techniques has made it possible to significantly improve the insecticidal efficacy of fungi and their tolerance to adverse conditions, including UV. These advances have been achieved by combining new knowledge derived from basic studies of the molecular biology of these pathogens, technical developments that enable very precise regulation of gene expression, and genes encoding insecticidal proteins from other organisms, particularly spiders and scorpions. Recent coverage of genomes is helping determine the identity, origin, and evolution of traits needed for diverse lifestyles and host switching. In future, such knowledge combined with the precision and malleability of molecular techniques will allow design of multiple pathogens with different strategies and host ranges to be used for different ecosystems, and that will avoid the possibility of the host developing resistance. With increasing public concern over the continued use of synthetic chemical insecticides, these new types of biological insecticides offer a range of environmental-friendly options for cost-effective control of insect pests. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Eurasian golden jackal as host of canine vector-borne protists

    Czech Academy of Sciences Publication Activity Database

    Mitková, B.; Hrazdilová, K.; D'Amico, G.; Duscher, G. G.; Suchentrunk, F.; Forejtek, P.; Gherman, C.M.; Matei, I.A.; Ionică, A.M.; Daskalaki, A.A.; Mihalca, A. D.; Votýpka, Jan; Hulva, P.; Modrý, David

    2017-01-01

    Roč. 10, APR 14 (2017), č. článku 183. ISSN 1756-3305 Institutional support: RVO:60077344 Keywords : Eurasian golden jackal * Babesia * Hepatozoon * Theileria annae * Leishmania Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine OBOR OECD: Veterinary science Impact factor: 3.080, year: 2016

  4. Tick-Pathogen Interactions and Vector Competence: Identification of Molecular Drivers for Tick-Borne Diseases

    Czech Academy of Sciences Publication Activity Database

    de la Fuente, J.; Antunes, S.; Bonnet, S.; Cabezas Cruz, Alejandro; Domingos, A.G.; Estrada-Peňa, A.; Johnson, N.; Kocan, K.M.; Mansfield, K. L.; Nijhof, A.M.; Papa, A.; Rudenko, Natalia; Villar, M.; Alberdi, P.; Torina, A.; Ayllón, N.; Vancová, Marie; Golovchenko, Maryna; Grubhoffer, Libor; Caracappa, S.; Fooks, A. R.; Gortazar, C.; Rego, Ryan O. M.

    2017-01-01

    Roč. 7, APR 7 (2017), č. článku 114. ISSN 2235-2988 EU Projects: European Commission(XE) 278976 - ANTIGONE Institutional support: RVO:60077344 Keywords : tick * Anaplasma * flavivirus * Babesia * Borrelia * Microbiome * immunology * vaccine Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Biochemistry and molecular biology Impact factor: 4.300, year: 2016

  5. Regulation of the Immune Response to alpha-Gal and Vector-borne Diseases

    Czech Academy of Sciences Publication Activity Database

    Cabezas-Cruz, A.; Mateos-Hernández, L.; Pérez-Cruz, M.; Valdés, James J.; Fernández de Mera, I.G.; Villar, M.; de la Fuente, J.

    2015-01-01

    Roč. 31, č. 10 (2015), s. 470-476 ISSN 1471-4922 R&D Projects: GA MŠk(CZ) EE2.3.30.0032 EU Projects: European Commission(XE) 278976 Institutional support: RVO:60077344 Keywords : red meat allergy * host defenses * tick bites Subject RIV: EI - Biotechnology ; Bionics Impact factor: 7.295, year: 2015

  6. Recent Weather Extremes and Impacts on Agricultural Production and Vector-Borne Disease Outbreak Patterns

    Science.gov (United States)

    2014-03-21

    extracted from the USDA Production, Supply, and Distribution Online (PSD) electronic database (http://www.fas.usda.gov/psdonline/) for the focal regions...Precipitation Climatology Project [31] (Table 1). Various publicly-available databases were surveyed to develop maps of outbreak locations of dengue, Rift...rates of leaf photosynthesis and severely reduced the development of floral buds thus reducing yields [33]. Direct losses from the drought approached $10

  7. A Comparison of Dynamics in Two Models for the Spread of a Vector-Borne Disease

    DEFF Research Database (Denmark)

    Græsbøll, Kaare; Sumner, T.; Enøe, Claes

    2016-01-01

    In 2007, bluetongue virus (BTV) was introduced to both Denmark (DK) and the United Kingdom (UK). For this reason, simulation models were built to predict scenarios for future incursions. The DK and UK models have a common description of within-herd dynamics, but differ greatly in their descriptio...... sensitivity to the level of vaccine uptake and has lower variability compared with a kernel-based model. However, a model using a transmission kernel requires less detailed data and is often faster....

  8. [Health care reform, decentralization, prevention and control of vector-borne diseases].

    Science.gov (United States)

    Schmunis, G A; Dias, J C

    2000-01-01

    Economic policies are changing Latin American health programs, particularly promoting decentralization. Numerous difficulties thus arise for the control of endemic diseases, since such activities traditionally depend on vertical, and centralized structures. Theoretical arguments in favor of decentralization notwithstanding, no such tradition exists at the county level. The lack of program expertise at peripheral levels, intensive staff turnover, and even corruption are additional difficulties. Hence, the simple bureaucratic transfer of activities from the Federal to county level is often irresponsible. The loss of priority for control of endemic diseases in Latin America may mean the inexorable extinction of traditional control services. Malaria, dengue fever, and Chagas disease programs are examples of the loss of expertise and effectiveness in Latin America. A better strategy for responsible decentralization is required. In particular, a shared transition involving all governmental levels is desirable to effectively modernize programs. Maintenance of regional reference centers to ensure supervision, surveillance, and training is suggested.

  9. Impact of Global Climate on Rift Valley Fever and other Vector-borne Disease Outbreaks

    Science.gov (United States)

    Linthicum, K. J.

    2017-12-01

    Rift Valley fever is a viral disease of animals and humans in Africa and the Middle East that is transmitted by mosquitoes. Since the virus was first isolated in Kenya in 1930 it has caused significant impact to animal and human health and national economies, and it is of concern to the international agricultural and public health community. In this presentation we will describe the (1) ecology of disease transmission as it relates to climate, (2) the impact of climate and other environmental conditions on outbreaks, (3) the ability to use global climate information to predict outbreaks, (4) effective response activities, and (4) the potential to mitigate globalization.

  10. Chameleon vector bosons

    International Nuclear Information System (INIS)

    Nelson, Ann E.; Walsh, Jonathan

    2008-01-01

    We show that for a force mediated by a vector particle coupled to a conserved U(1) charge, the apparent range and strength can depend on the size and density of the source, and the proximity to other sources. This chameleon effect is due to screening from a light charged scalar. Such screening can weaken astrophysical constraints on new gauge bosons. As an example we consider the constraints on chameleonic gauged B-L. We show that although Casimir measurements greatly constrain any B-L force much stronger than gravity with range longer than 0.1 μm, there remains an experimental window for a long-range chameleonic B-L force. Such a force could be much stronger than gravity, and long or infinite range in vacuum, but have an effective range near the surface of the earth which is less than a micron.

  11. Covariant Lyapunov vectors

    International Nuclear Information System (INIS)

    Ginelli, Francesco; Politi, Antonio; Chaté, Hugues; Livi, Roberto

    2013-01-01

    Recent years have witnessed a growing interest in covariant Lyapunov vectors (CLVs) which span local intrinsic directions in the phase space of chaotic systems. Here, we review the basic results of ergodic theory, with a specific reference to the implications of Oseledets’ theorem for the properties of the CLVs. We then present a detailed description of a ‘dynamical’ algorithm to compute the CLVs and show that it generically converges exponentially in time. We also discuss its numerical performance and compare it with other algorithms presented in the literature. We finally illustrate how CLVs can be used to quantify deviations from hyperbolicity with reference to a dissipative system (a chain of Hénon maps) and a Hamiltonian model (a Fermi–Pasta–Ulam chain). This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Lyapunov analysis: from dynamical systems theory to applications’. (paper)

  12. Smuggling across the border: how arthropod-borne pathogens evade and exploit the host defense system of the skin.

    Science.gov (United States)

    Bernard, Quentin; Jaulhac, Benoit; Boulanger, Nathalie

    2014-05-01

    The skin is a critical barrier between hosts and pathogens in arthropod-borne diseases. It harbors many resident cells and specific immune cells to arrest or limit infections by secreting inflammatory molecules or by directly killing pathogens. However, some pathogens are able to use specific skin cells and arthropod saliva for their initial development, to hide from the host immune system, and to establish persistent infection in the vertebrate host. A better understanding of the initial mechanisms taking place in the skin should allow the development of new strategies to fight these vector-borne pathogens that are spread worldwide and are of major medical importance.

  13. Effectiveness of Large-Scale Chagas Disease Vector Control Program in Nicaragua by Residual Insecticide Spraying Against Triatoma dimidiata.

    Science.gov (United States)

    Yoshioka, Kota; Nakamura, Jiro; Pérez, Byron; Tercero, Doribel; Pérez, Lenin; Tabaru, Yuichiro

    2015-12-01

    Chagas disease is one of the most serious health problems in Latin America. Because the disease is transmitted mainly by triatomine vectors, a three-phase vector control strategy was used to reduce its vector-borne transmission. In Nicaragua, we implemented an indoor insecticide spraying program in five northern departments to reduce house infestation by Triatoma dimidiata. The spraying program was performed in two rounds. After each round, we conducted entomological evaluation to compare the vector infestation level before and after spraying. A total of 66,200 and 44,683 houses were sprayed in the first and second spraying rounds, respectively. The entomological evaluation showed that the proportion of houses infested by T. dimidiata was reduced from 17.0% to 3.0% after the first spraying, which was statistically significant (P vector control strategies, and implementation of sustainable vector surveillance. © The American Society of Tropical Medicine and Hygiene.

  14. Insecticide Resistance in the Dengue Vector Aedes aegypti from Martinique: Distribution, Mechanisms and Relations with Environmental Factors

    OpenAIRE

    Marcombe , Sébastien; Blanc Mathieu , Romain; Pocquet , Nicolas; Riaz , Muhammad-Asam; Poupardin , Rodolphe; Sélior , Serge; Darriet , Frédéric; Reynaud , Stéphane; Yebakima , André; Corbel , Vincent; David , Jean-Philippe; Chandre , Fabrice

    2012-01-01

    International audience; Dengue is an important mosquito borne viral disease in Martinique Island (French West Indies). The viruses responsible for dengue are transmitted by Aedes aegypti, an indoor day-biting mosquito. The most effective proven method for disease prevention has been by vector control by various chemical or biological means. Unfortunately insecticide resistance has already been observed on the Island and recently showed to significantly reduce the efficacy of vector control in...

  15. The 7Li(d-vector,n0)8Be and 7Li(d-vector,n1)8Be reactions below 160 keV

    International Nuclear Information System (INIS)

    Sabourov, A.; Ahmed, M. W.; Blackston, M. A.; Crowell, A. S.; Howell, C. R.; Joshi, K.; Nelson, S. O.; Perdue, B. A.; Sabourov, K.; Tonchev, A.; Weller, H. R.; Prior, R. M.; Spraker, M. C.; Braizinha, B.; Kalantar-Nayestanaki, N.

    2006-01-01

    The polarization observables have been determined for the 7 Li(d-vector,n 0 ) 8 Be and 7 Li(d-vector ,n 1 ) 8 Be reactions at beam energies between 80 and 160 keV. A Transition Matrix Element (TME) analysis revealed unique, dominant p-wave solutions for both neutron channels. The polarization observables were compared with distorted wave Born approximation (DWBA) and coupled reaction channels (CRC) calculations. The general features of the data can be reproduced by the CRC calculations when a large target spin-orbit interaction is included. However, serious discrepancies are observed when the TMEs of the theory and experiment are compared

  16. Interplays between soil-borne plant viruses and RNA silencing-mediated antiviral defense in roots

    Directory of Open Access Journals (Sweden)

    Ida Bagus Andika

    2016-09-01

    Full Text Available Although the majority of plant viruses are transmitted by arthropod vectors and invade the host plants through the aerial parts, there is a considerable number of plant viruses that infect roots via soil-inhabiting vectors such as plasmodiophorids, chytrids, and nematodes. These soil-borne viruses belong to diverse families, and many of them cause serious diseases in major crop plants. Thus, roots are important organs for the life cycle of many viruses. Compared to shoots, roots have a distinct metabolism and particular physiological characteristics due to the differences in development, cell composition, gene expression patterns, and surrounding environmental conditions. RNA silencing is an important innate defense mechanism to combat virus infection in plants, but the specific information on the activities and molecular mechanism of RNA silencing-mediated viral defense in root tissue is still limited. In this review, we summarize and discuss the current knowledge regarding RNA silencing aspects of the interactions between soil-borne viruses and host plants. Overall, research evidence suggests that soil-borne viruses have evolved to adapt to the distinct mechanism of antiviral RNA silencing in roots.

  17. Molecular investigation of tick-borne pathogens in dogs from Luanda, Angola.

    Science.gov (United States)

    Cardoso, Luís; Oliveira, Ana Cristina; Granada, Sara; Nachum-Biala, Yaarit; Gilad, Matan; Lopes, Ana Patrícia; Sousa, Sérgio Ramalho; Vilhena, Hugo; Baneth, Gad

    2016-05-10

    No molecular data have been available on tick-borne pathogens that infect dogs from Angola. The occurrence of agents from the genera Anaplasma, Babesia, Ehrlichia and Hepatozoon was assessed in 103 domestic dogs from Luanda, by means of the polymerase chain reaction (PCR) and DNA sequence analysis. Forty-six dogs (44.7 %) were positive for at least one pathogen. Twenty-one animals (20.4 %) were found infected with Anaplasma platys, 18 (17.5 %) with Hepatozoon canis, six (5.8 %) with Ehrlichia canis, six (5.8 %) with Babesia vogeli, one (1.0 %) with Babesia gibsoni and one (1.0 %) with an unnamed Babesia sp. The molecular frequency of single infections taken together was 37.9 % and that of co-infections with several combinations of two pathogens accounted for 6.8 % of the animals. This is the first report of A. platys, B. vogeli, B. gibsoni, E. canis and H. canis infections diagnosed by PCR in domestic dogs from Angola. The present study provides evidence that dogs in Luanda are widely exposed to, and at risk of becoming infected with, tick-borne pathogens. Further investigation is needed, including a larger number of animals, canine populations from other cities and provinces of the country, as well as potential vector ticks, aiming at better characterizing and controlling canine vector-borne diseases in Angola.

  18. Surveillance of Mosquitoes and Selected Arthropod-Borne Viruses in the Context of Milan EXPO 2015

    Directory of Open Access Journals (Sweden)

    Mario Chiari

    2016-07-01

    Full Text Available From 1 May 2015 to 31 October 2015 over 20 million visitors from all over the world visited the Universal Exhibition (EXPO hosted by Milan (Lombardy region, Italy, raising concerns about the possible introduction of mosquito-borne diseases from endemic countries. The entomological surveillance protocol performed in Lombardy over the last three years was implemented in the EXPO area and in the two major regional airports using both Center for Disease Control CO2 and Biogents Sentinel traps. This surveillance aimed to estimate the presence and densities of putative vectors, and also to support investigations, including the vector species involved and area of diffusion, on the local spread of Chikungunya, Dengue and West Nile viruses (WNV by competent vectors. From 3544 mosquitoes belonging to five different species, 28 pools of Culex spp. and 45 pools of Aedes spp. were screened for the presence of WNV, and for both Chikungunya and flaviviruses, respectively. The entomological surveillance highlighted a low density of potential vectors in the surveyed areas and did not reveal the presence of Chikungunya or Dengue viruses in the local competent vectors inside the EXPO area or in the two airports. In addition, the surveillance reported a low density of Culex spp. mosquitoes, which all tested negative for WNV.

  19. The extinction of dengue through natural vulnerability of its vectors.

    Directory of Open Access Journals (Sweden)

    Craig R Williams

    Full Text Available BACKGROUND: Dengue is the world's most important mosquito-borne viral illness. Successful future management of this disease requires an understanding of the population dynamics of the vector, especially in the context of changing climates. Our capacity to predict future dynamics is reflected in our ability to explain the significant historical changes in the distribution and abundance of the disease and its vector. METHODOLOGY/PRINCIPAL FINDINGS: Here we combine daily weather records with simulation modelling techniques to explain vector (Aedes aegypti (L. persistence within its current and historic ranges in Australia. We show that, in regions where dengue presently occurs in Australia (the Wet Tropics region of Far North Queensland, conditions are persistently suitable for year-round adult Ae. aegypti activity and oviposition. In the historic range, however, the vector is vulnerable to periodic extinction due to the combined influence of adult activity constraints and stochastic loss of suitable oviposition sites. CONCLUSIONS/SIGNIFICANCE: These results, together with changes in water-storage behaviour by humans, can explain the observed historical range contraction of the disease vector. For these reasons, future eradication of dengue in wet tropical regions will be extremely difficult through classical mosquito control methods alone. However, control of Ae. aegypti in sub-tropical and temperate regions will be greatly facilitated by government policy regulating domestic water-storage. Exploitation of the natural vulnerabilities of dengue vectors (e.g., habitat specificity, climatic limitations should be integrated with the emerging novel transgenic and symbiotic bacterial control techniques to develop future control and elimination strategies.

  20. Some models for epidemics of vector-transmitted diseases

    Directory of Open Access Journals (Sweden)

    Fred Brauer

    2016-10-01

    Full Text Available Vector-transmitted diseases such as dengue fever and chikungunya have been spreading rapidly in many parts of the world. The Zika virus has been known since 1947 and invaded South America in 2013. It can be transmitted not only by (mosquito vectors but also directly through sexual contact. Zika has developed into a serious global health problem because, while most cases are asymptomatic or very light, babies born to Zika - infected mothers may develop microcephaly and other very serious birth defects.We formulate and analyze two epidemic models for vector-transmitted diseases, one appropriate for dengue and chikungunya fever outbreaks and one that includes direct transmission appropriate for Zika virus outbreaks. This is especially important because the Zika virus is the first example of a disease that can be spread both indirectly through a vector and directly (through sexual contact. In both cases, we obtain expressions for the basic reproduction number and show how to use the initial exponential growth rate to estimate the basic reproduction number. However, for the model that includes direct transmission some additional data would be needed to identify the fraction of cases transmitted directly. Data for the 2015 Zika virus outbreak in Barranquilla, Colombia has been used to fit parameters to the model developed here and to estimate the basic reproduction number.

  1. Simplified Representation of Vector Fields

    NARCIS (Netherlands)

    Telea, Alexandru; Wijk, Jarke J. van

    1999-01-01

    Vector field visualization remains a difficult task. Although many local and global visualization methods for vector fields such as flow data exist, they usually require extensive user experience on setting the visualization parameters in order to produce images communicating the desired insight. We

  2. Estimation of Motion Vector Fields

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    1993-01-01

    This paper presents an approach to the estimation of 2-D motion vector fields from time varying image sequences. We use a piecewise smooth model based on coupled vector/binary Markov random fields. We find the maximum a posteriori solution by simulated annealing. The algorithm generate sample...... fields by means of stochastic relaxation implemented via the Gibbs sampler....

  3. GPU Accelerated Vector Median Filter

    Science.gov (United States)

    Aras, Rifat; Shen, Yuzhong

    2011-01-01

    Noise reduction is an important step for most image processing tasks. For three channel color images, a widely used technique is vector median filter in which color values of pixels are treated as 3-component vectors. Vector median filters are computationally expensive; for a window size of n x n, each of the n(sup 2) vectors has to be compared with other n(sup 2) - 1 vectors in distances. General purpose computation on graphics processing units (GPUs) is the paradigm of utilizing high-performance many-core GPU architectures for computation tasks that are normally handled by CPUs. In this work. NVIDIA's Compute Unified Device Architecture (CUDA) paradigm is used to accelerate vector median filtering. which has to the best of our knowledge never been done before. The performance of GPU accelerated vector median filter is compared to that of the CPU and MPI-based versions for different image and window sizes, Initial findings of the study showed 100x improvement of performance of vector median filter implementation on GPUs over CPU implementations and further speed-up is expected after more extensive optimizations of the GPU algorithm .

  4. Archimedeanization of ordered vector spaces

    OpenAIRE

    Emelyanov, Eduard Yu.

    2014-01-01

    In the case of an ordered vector space with an order unit, the Archimedeanization method has been developed recently by V.I Paulsen and M. Tomforde. We present a general version of the Archimedeanization which covers arbitrary ordered vector spaces.

  5. Vector superconductivity in cosmic strings

    International Nuclear Information System (INIS)

    Dvali, G.R.; Mahajan, S.M.

    1992-03-01

    We argue that in most realistic cases, the usual Witten-type bosonic superconductivity of the cosmic string is automatically (independent of the existence of superconducting currents) accompanied by the condensation of charged gauge vector bosons in the core giving rise to a new vector type superconductivity. The value of the charged vector condensate is related with the charged scalar expectation value, and vanishes only if the latter goes to zero. The mechanism for the proposed vector superconductivity, differing fundamentally from those in the literature, is delineated using the simplest realistic example of the two Higgs doublet standard model interacting with the extra cosmic string. It is shown that for a wide range of parameters, for which the string becomes scalarly superconducting, W boson condensates (the sources of vector superconductivity) are necessarily excited. (author). 14 refs

  6. Wavefield separation by energy norm Born scattering

    KAUST Repository

    Sun, Bingbing

    2017-08-17

    In Reflection Based Waveform Inversion, the gradient is computed by cross-correlating the direct and Born scattered wavefield with their adjoints applied to the data residuals. In this case, the transmitted part of the Born scattered wavefield produces high wavenumber artifacts, which would harm the convergence of the inversion process. We propose an efficient Energy Norm Born Scattering (ENBS) to attenuate the transmission components of the Born modeling, and allow it to produce only reflections. ENBS is derived from the adjoint of the Energy Norm (inverse scattering) imaging condition and in order to get deeper insights of how this method works, we show analytically that given an image, in which reflectivity is represented by a Dirac delta function, ENBS attenuates transmission energy perfectly. We use numerical examples to demonstrate that ENBS works in both the time and the frequency domain. We also show that in reflection waveform inversion (RWI) the wave path constructed by ENBS would be cleaner and free of high wavenumber artifacts associated with conventional Born scattering.

  7. Wavefield separation by energy norm Born scattering

    KAUST Repository

    Sun, Bingbing; Alkhalifah, Tariq Ali

    2017-01-01

    In Reflection Based Waveform Inversion, the gradient is computed by cross-correlating the direct and Born scattered wavefield with their adjoints applied to the data residuals. In this case, the transmitted part of the Born scattered wavefield produces high wavenumber artifacts, which would harm the convergence of the inversion process. We propose an efficient Energy Norm Born Scattering (ENBS) to attenuate the transmission components of the Born modeling, and allow it to produce only reflections. ENBS is derived from the adjoint of the Energy Norm (inverse scattering) imaging condition and in order to get deeper insights of how this method works, we show analytically that given an image, in which reflectivity is represented by a Dirac delta function, ENBS attenuates transmission energy perfectly. We use numerical examples to demonstrate that ENBS works in both the time and the frequency domain. We also show that in reflection waveform inversion (RWI) the wave path constructed by ENBS would be cleaner and free of high wavenumber artifacts associated with conventional Born scattering.

  8. Autophagy pathway induced by a plant virus facilitates viral spread and transmission by its insect vector.

    Directory of Open Access Journals (Sweden)

    Yong Chen

    2017-11-01

    Full Text Available Many viral pathogens are persistently transmitted by insect vectors and cause agricultural or health problems. Generally, an insect vector can use autophagy as an intrinsic antiviral defense mechanism against viral infection. Whether viruses can evolve to exploit autophagy to promote their transmission by insect vectors is still unknown. Here, we show that the autophagic process is triggered by the persistent replication of a plant reovirus, rice gall dwarf virus (RGDV in cultured leafhopper vector cells and in intact insects, as demonstrated by the appearance of obvious virus-containing double-membrane autophagosomes, conversion of ATG8-I to ATG8-II and increased level of autophagic flux. Such virus-containing autophagosomes seem able to mediate nonlytic viral release from cultured cells or facilitate viral spread in the leafhopper intestine. Applying the autophagy inhibitor 3-methyladenine or silencing the expression of Atg5 significantly decrease viral spread in vitro and in vivo, whereas applying the autophagy inducer rapamycin or silencing the expression of Torc1 facilitate such viral spread. Furthermore, we find that activation of autophagy facilitates efficient viral transmission, whereas inhibiting autophagy blocks viral transmission by its insect vector. Together, these results indicate a plant virus can induce the formation of autophagosomes for carrying virions, thus facilitating viral spread and transmission by its insect vector. We believe that such a role for virus-induced autophagy is common for vector-borne persistent viruses during their transmission by insect vectors.

  9. Economic downturn results in tick-borne disease upsurge

    Directory of Open Access Journals (Sweden)

    Randolph Sarah E

    2011-03-01

    Full Text Available Abstract Background The emergence of zoonoses is due both to changes in human activities and to changes in their natural wildlife cycles. One of the most significant vector-borne zoonoses in Europe, tick-borne encephalitis (TBE, doubled in incidence in 1993, largely as a consequence of the socio-economic transition from communism to capitalism and associated environmental changes. Methods To test the effect of the current economic recession, unemployment in 2009 and various socio-economic indices were compared to weather indices (derived from principal component analyses as predictors for the change in TBE case numbers in 2009 relative to 2004-08, for 14 European countries. Results Greatest increases in TBE incidence occurred in Latvia, Lithuania and Poland (91, 79 and 45%, respectively. The weather was rejected as an explanatory variable. Indicators of high background levels of poverty, e.g. percent of household expenditure on food, were significant predictors. The increase in unemployment in 2009 relative to 2008 together with 'in-work risk of poverty' is the only case in which a multivariate model has a second significant term. Conclusion Background socio-economic conditions determine susceptibility to risk of TBE, while increased unemployment triggered a sudden increase in risk. Mechanisms behind this result may include reduced resistance to infection through stress; reduced uptake of costly vaccination; and more exposure of people to infected ticks in their forest habitat as they make greater use of wild forest foods, especially in those countries, Lithuania and Poland, with major marketing opportunities in such products. Recognition of these risk factors could allow more effective protection through education and a vaccination programme targeted at the economically most vulnerable.

  10. Economic downturn results in tick-borne disease upsurge.

    Science.gov (United States)

    Godfrey, Elinor R; Randolph, Sarah E

    2011-03-15

    The emergence of zoonoses is due both to changes in human activities and to changes in their natural wildlife cycles. One of the most significant vector-borne zoonoses in Europe, tick-borne encephalitis (TBE), doubled in incidence in 1993, largely as a consequence of the socio-economic transition from communism to capitalism and associated environmental changes. To test the effect of the current economic recession, unemployment in 2009 and various socio-economic indices were compared to weather indices (derived from principal component analyses) as predictors for the change in TBE case numbers in 2009 relative to 2004-08, for 14 European countries. Greatest increases in TBE incidence occurred in Latvia, Lithuania and Poland (91, 79 and 45%, respectively). The weather was rejected as an explanatory variable. Indicators of high background levels of poverty, e.g. percent of household expenditure on food, were significant predictors. The increase in unemployment in 2009 relative to 2008 together with 'in-work risk of poverty' is the only case in which a multivariate model has a second significant term. Background socio-economic conditions determine susceptibility to risk of TBE, while increased unemployment triggered a sudden increase in risk. Mechanisms behind this result may include reduced resistance to infection through stress; reduced uptake of costly vaccination; and more exposure of people to infected ticks in their forest habitat as they make greater use of wild forest foods, especially in those countries, Lithuania and Poland, with major marketing opportunities in such products. Recognition of these risk factors could allow more effective protection through education and a vaccination programme targeted at the economically most vulnerable.

  11. Soil borne gungi associated with different vegetable crop in sindh, pakistan

    International Nuclear Information System (INIS)

    Usman, F.; Abid, M.; Hussain, F.

    2014-01-01

    Different soil-borne fungi are responsible for reducing the yield of vegetables throughout the world including Pakistan. There are several soil borne fungal pathogens which aggressively infect vegetable crops. Surveys conducted during September 2010 to October 2011, demonstrated that a great diversity of soil borne plant pathogens associated with different vegetables prevail in vegetable growing areas of Sindh such as Tando Allahayar, Mirpurkhas, Ghotaki, Khairpur, Kunri, Umerkot and Karachi, etc. Our study noted in total thirteen different genera of fungi isolated from vegetable crops (cabbage, brinjal, tomato, radish and spinach). Isolated fungi identified included Alternaria solani, Aspergillus flavus, A. fumigatus, A. niger, A. oryzae, A. terrus, Aeromonium fusidiocles, Cladosporium sp., Drechselra hawaiiensis, Eurotium berbanbrum, Fusarium oxysporum, Macrophomina phaseolina, Penicillium commune, Rhizoctonia solani, Trichoderma harzianum, Ulocladium sp., and unidentified black mycelium from the soil and roots of vegetable crops. In addition, it was found that soil is commonly infected by soil-borne fungi and eventually results in heavy losses of vegetable yield in the vegetable growing areas of Sindh province. The infection rapidly increased due to many factors such as, presence of moisture, excess of water and infection may be caused by winds, gales and dust storms as well as by mechanical vectors. (author)

  12. 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.

  13. Tornado-borne missile speeds. Final report

    International Nuclear Information System (INIS)

    Simiu, E.; Cordes, M.

    1976-04-01

    An investigation of the question of tornado-borne missile speeds was carried out, with a view to identify pertinent areas of uncertainty and to estimate credible tornado-borne missile speeds - within the limitations inherent in the present state of the art. The investigation consists of two parts: (1) a study in which a rational model for the missile motion is proposed, and numerical experiments are carried out corresponding to various assumptions on the initial conditions of the missile motion, the structure of the tornado flow, and the aerodynamic properties of the missile; (2) a theoretical and experimental study of tornado-borne missile aerodynamics, conducted by Colorado State Univ. (CSU) to be covered in a separate report by CSU. In the present report, the factors affecting missile motion and their influence upon such motion are examined

  14. On transparent potentials: a Born approximation study

    International Nuclear Information System (INIS)

    Coudray, C.

    1980-01-01

    In the frame of the scattering inverse problem at fixed energy, a class of potentials transparent in Born approximation is obtained. All these potentials are spherically symmetric and are oscillating functions of the reduced radial variable. Amongst them, the Born approximation of the transparent potential of the Newton-Sabatier method is found. In the same class, quasi-transparent potentials are exhibited. Very general features of potentials transparent in Born approximation are then stated. And bounds are given for the exact scattering amplitudes corresponding to most of the potentials previously exhibited. These bounds, obtained at fixed energy, and for large values of the angular momentum, are found to be independent on the energy

  15. The Polerovirus Minor Capsid Protein Determines Vector Specificity and Intestinal Tropism in the Aphid

    Science.gov (United States)

    Brault, Véronique; Périgon, Sophie; Reinbold, Catherine; Erdinger, Monique; Scheidecker, Danièle; Herrbach, Etienne; Richards, Ken; Ziegler-Graff, Véronique

    2005-01-01

    Aphid transmission of poleroviruses is highly specific, but the viral determinants governing this specificity are unknown. We used a gene exchange strategy between two poleroviruses with different vectors, Beet western yellows virus (BWYV) and Cucurbit aphid-borne yellows virus (CABYV), to analyze the role of the major and minor capsid proteins in vector specificity. Virus recombinants obtained by exchanging the sequence of the readthrough domain (RTD) between the two viruses replicated in plant protoplasts and in whole plants. The hybrid readthrough protein of chimeric viruses was incorporated into virions. Aphid transmission experiments using infected plants or purified virions revealed that vector specificity is driven by the nature of the RTD. BWYV and CABYV have specific intestinal sites in the vectors for endocytosis: the midgut for BWYV and both midgut and hindgut for CABYV. Localization of hybrid virions in aphids by transmission electron microscopy revealed that gut tropism is also determined by the viral origin of the RTD. PMID:16014930

  16. [Public health pests. Arthropods and rodents as causative disease agents as well as reservoirs and vectors of pathogens].

    Science.gov (United States)

    Faulde, M; Freise, J

    2014-05-01

    Globally, infectious diseases pose the most important cause of death. Among known human pathogenic diseases, approximately 50 % are zoonoses. When considering emerging infectious diseases separately 73 % currently belong to the group of zoonoses. In Central Europe, hard ticks show by far the biggest potential as vectors of agents of human disease. Lyme borreliosis, showing an estimated annual incidence between 60,000 and 214,000 cases is by far the most frequent tick-borne disease in Germany. Continually, formerly unknown disease agents could be discovered in endemic vector species. Additionally, introduction of new arthropod vectors and/or agents of disease occur constantly. Recently, five mosquito species of the genus Aedes have been newly introduced to Europe where they are currently spreading in different regions. Uncommon autochthonous transmission of dengue and chikungunya fever viruses in Southern Europe could be directly linked to these vector species and of these Ae. albopictus and Ae. japonicus are currently reported to occur in Germany. The German Protection against Infection Act only covers the control of public health pests which are either active hematophagous vectors or mechanical transmitters of agents of diseases. Use of officially recommended biocidal products aiming to interrupt transmission cycles of vector-borne diseases, is confined to infested buildings only, including sewage systems in the case of Norway rat control. Outdoor vectors, such as hard ticks and mosquitoes, are currently not taken into consideration. Additionally, adjustments of national public health regulations, detailed arthropod vector and rodent reservoir mapping, including surveillance of vector-borne disease agents, are necessary in order to mitigate future disease risks.

  17. Detection and molecular characterization of the mosquito-borne filarial nematode Setaria tundra in Danish roe deer (Capreolus capreolus)

    DEFF Research Database (Denmark)

    Enemark, Heidi Larsen; Oksanen, Antti; Chriél, Mariann

    2017-01-01

    Setaria tundra is a mosquito-borne filarial nematode of cervids in Europe. It has recently been associated with an emerging epidemic disease causing severe morbidity and mortality in reindeer and moose in Finland. Here, we present the first report of S. tundra in six roe deer (Capreolus capreolus...... Europe. Roe deer are generally considered as asymptomatic carriers and their numbers in Denmark have increased significantly in recent decades. In light of climatic changes which result in warmer, more humid weather in Scandinavia greater numbers of mosquitoes and, especially, improved conditions...... for development of parasite larvae in the mosquito vectors are expected, which may lead to increasing prevalence of S. tundra. Monitoring of this vector-borne parasite may thus be needed in order to enhance the knowledge of factors promoting its expansion and prevalence as well as predicting disease outbreaks. (C...

  18. Molecular survey of arthropod-borne pathogens in sheep keds (Melophagus ovinus), Central Europe.

    Science.gov (United States)

    Rudolf, Ivo; Betášová, Lenka; Bischof, Vlastimil; Venclíková, Kristýna; Blažejová, Hana; Mendel, Jan; Hubálek, Zdeněk; Kosoy, Michael

    2016-10-01

    In the study, we screened a total of 399 adult sheep keds (Melophagus ovinus) for the presence of RNA and DNA specific for arboviral, bacterial, and protozoan vector-borne pathogens. All investigated keds were negative for flaviviruses, phleboviruses, bunyaviruses, Borrelia burgdorferi, Rickettsia spp., Anaplasma phagocytophilum, "Candidatus Neoehrlichia mikurensis," and Babesia spp. All ked pools were positive for Bartonella DNA. The sequencing of the amplified fragments of the gltA and 16S-23S rRNA demonstrated a 100 % homology with Bartonella melophagi previously isolated from a sheep ked and from human blood in the USA. The identification of B. melophagi in sheep keds in Central Europe highlights needs extending a list of hematophagous arthropods beyond ticks and mosquitoes for a search of emerging arthropod-borne pathogens.

  19. Pap Tests and Foreign-Born Women

    Centers for Disease Control (CDC) Podcasts

    2007-11-26

    Foreign-born women living in the U.S. are less likely to have Pap tests to detect cervical cancer than women born in this country. The problem is worse for women from certain countries or regions. Find out why this is a disturbing trend, who these women are and why they are less likely to get a Pap test, and what CDC is doing about it.  Created: 11/26/2007 by National Breast and Cervical Cancer Early Detection Program.   Date Released: 12/7/2007.

  20. Probabilities from entanglement, Born's rule from envariance

    International Nuclear Information System (INIS)

    Zurek, W.

    2005-01-01

    Full text: I shall discuss consequences of envariance (environment - assisted invariance) symmetry exhibited by entangled quantum states. I shall focus on the implications of envariance for the understanding of the origins and nature of ignorance, and, hence, for the origin of probabilities in physics. While the derivation of the Born's rule for probabilities (pk IykI2) is the principal accomplishment of this research, I shall explore the possibility that several other symptoms of the quantum - classical transition that are a consequence of decoherence can be justified directly by envariance -- i.e., without invoking Born's rule. (author)

  1. Born's reciprocity principle in stochastic phase space

    International Nuclear Information System (INIS)

    Prugovecki, E.

    1981-01-01

    It is shown that the application of Born's reciprocity principle to relativistic quantum mechanics in stochastic phase space (by the requirement that the proper wave functions of extended particles satisfy the Born-Lande as well as the Klein-Gordon equation) leads to the unique determination of these functions for any given value of their rms radius. The resulting particle propagators display not only Lorentz but also reciprocal invariance. This feature remains true even in the case of mass-zero particles, such as photons, when their localization is achieved by means of extended test particles whose proper wave functions obey the reciprocity principle. (author)

  2. A survey of canine tick-borne diseases in India

    Directory of Open Access Journals (Sweden)

    Coleman Glen T

    2011-07-01

    Full Text Available Abstract Background There are few published reports on canine Babesia, Ehrlichia, Anaplasma, Hepatozoon and haemotropic Mycoplasma infections in India and most describe clinical disease in individual dogs, diagnosed by morphological observation of the microorganisms in stained blood smears. This study investigated the occurrence and distribution of canine tick-borne disease (TBD pathogens using a combination of conventional and molecular diagnostic techniques in four cities in India. Results On microscopy examination, only Hepatozoon gamonts were observed in twelve out of 525 (2.3%; 95% CI: 1.2, 4 blood smears. Using polymerase chain reaction (PCR, a total of 261 from 525 dogs (49.7%; 95% CI: 45.4, 54.1 in this study were infected with one or more canine tick-borne pathogen. Hepatozoon canis (30%; 95% CI: 26.0, 34.0 was the most common TBD pathogen found infecting dogs in India followed by Ehrlichia canis (20.6%; 95% CI: 17.2, 24.3, Mycoplasma haemocanis (12.2%; 95% CI: 9.5, 15.3, Anaplasma platys (6.5%; 95% CI: 4.5, 8.9, Babesia vogeli (5.5%, 95% CI: 3.7, 7.8 and Babesia gibsoni (0.2%, 95% CI: 0.01, 1.06. Concurrent infection with more than one TBD pathogen occurred in 39% of cases. Potential tick vectors, Rhipicephalus (most commonly and/or Haemaphysalis ticks were found on 278 (53% of dogs examined. Conclusions At least 6 species of canine tick-borne pathogens are present in India. Hepatozoon canis was the most common pathogen and ticks belonging to the genus Rhipicephalus were encountered most frequently. Polymerase chain reaction was more sensitive in detecting circulating pathogens compared with peripheral blood smear examination. As co-infections with canine TBD pathogens were common, Indian veterinary practitioners should be cognisant that the discovery of one such pathogen raises the potential for multiple infections which may warrant different clinical management strategies.

  3. Enhancing poxvirus vectors vaccine immunogenicity.

    Science.gov (United States)

    García-Arriaza, Juan; Esteban, Mariano

    2014-01-01

    Attenuated recombinant poxvirus vectors expressing heterologous antigens from pathogens are currently at various stages in clinical trials with the aim to establish their efficacy. This is because these vectors have shown excellent safety profiles, significant immunogenicity against foreign expressed antigens and are able to induce protective immune responses. In view of the limited efficacy triggered by some poxvirus strains used in clinical trials (i.e, ALVAC in the RV144 phase III clinical trial for HIV), and of the restrictive replication capacity of the highly attenuated vectors like MVA and NYVAC, there is a consensus that further improvements of these vectors should be pursuit. In this review we considered several strategies that are currently being implemented, as well as new approaches, to improve the immunogenicity of the poxvirus vectors. This includes heterologous prime/boost protocols, use of co-stimulatory molecules, deletion of viral immunomodulatory genes still present in the poxvirus genome, enhancing virus promoter strength, enhancing vector replication capacity, optimizing expression of foreign heterologous sequences, and the combined use of adjuvants. An optimized poxvirus vector triggering long-lasting immunity with a high protective efficacy against a selective disease should be sought.

  4. Stable piecewise polynomial vector fields

    Directory of Open Access Journals (Sweden)

    Claudio Pessoa

    2012-09-01

    Full Text Available Let $N={y>0}$ and $S={y<0}$ be the semi-planes of $mathbb{R}^2$ having as common boundary the line $D={y=0}$. Let $X$ and $Y$ be polynomial vector fields defined in $N$ and $S$, respectively, leading to a discontinuous piecewise polynomial vector field $Z=(X,Y$. This work pursues the stability and the transition analysis of solutions of $Z$ between $N$ and $S$, started by Filippov (1988 and Kozlova (1984 and reformulated by Sotomayor-Teixeira (1995 in terms of the regularization method. This method consists in analyzing a one parameter family of continuous vector fields $Z_{epsilon}$, defined by averaging $X$ and $Y$. This family approaches $Z$ when the parameter goes to zero. The results of Sotomayor-Teixeira and Sotomayor-Machado (2002 providing conditions on $(X,Y$ for the regularized vector fields to be structurally stable on planar compact connected regions are extended to discontinuous piecewise polynomial vector fields on $mathbb{R}^2$. Pertinent genericity results for vector fields satisfying the above stability conditions are also extended to the present case. A procedure for the study of discontinuous piecewise vector fields at infinity through a compactification is proposed here.

  5. Peridomestic Aedes malayensis and Aedes albopictus are capable vectors of arboviruses in cities.

    Science.gov (United States)

    Mendenhall, Ian H; Manuel, Menchie; Moorthy, Mahesh; Lee, Theodore T M; Low, Dolyce H W; Missé, Dorothée; Gubler, Duane J; Ellis, Brett R; Ooi, Eng Eong; Pompon, Julien

    2017-06-01

    Dengue and chikungunya are global re-emerging mosquito-borne diseases. In Singapore, sustained vector control coupled with household improvements reduced domestic mosquito populations for the past 45 years, particularly the primary vector Aedes aegypti. However, while disease incidence was low for the first 30 years following vector control implementation, outbreaks have re-emerged in the past 15 years. Epidemiological observations point to the importance of peridomestic infection in areas not targeted by control programs. We investigated the role of vectors in peri-domestic areas. We carried out entomological surveys to identify the Aedes species present in vegetated sites in highly populated areas and determine whether mosquitoes were present in open-air areas frequented by people. We compared vector competence of Aedes albopictus and Aedes malayensis with Ae. aegypti after oral infection with sympatric dengue serotype 2 and chikungunya viruses. Mosquito saliva was tested for the presence of infectious virus particles as a surrogate for transmission following oral infection. We identified Aedes albopictus and Aedes malayensis throughout Singapore and quantified their presence in forested and opened grassy areas. Both Ae. albopictus and Ae. malayensis can occupy sylvatic niches and were highly susceptible to both arboviruses. A majority of saliva of infected Ae. malayensis contained infectious particles for both viruses. Our study reveals the prevalence of competent vectors in peri-domestic areas, including Ae. malayensis for which we established the vector status. Epidemics can be driven by infection foci, which are epidemiologically enhanced in the context of low herd immunity, selective pressure on arbovirus transmission and the presence of infectious asymptomatic persons, all these conditions being present in Singapore. Learning from Singapore's vector control success that reduced domestic vector populations, but has not sustainably reduced arboviral incidence

  6. Molecular Detection and Characterization of Tick-borne Pathogens in Dogs and Ticks from Nigeria

    Science.gov (United States)

    Kamani, Joshua; Baneth, Gad; Mumcuoglu, Kosta Y.; Waziri, Ndadilnasiya E.; Eyal, Osnat; Guthmann, Yifat; Harrus, Shimon

    2013-01-01

    Background Only limited information is currently available on the prevalence of vector borne and zoonotic pathogens in dogs and ticks in Nigeria. The aim of this study was to use molecular techniques to detect and characterize vector borne pathogens in dogs and ticks from Nigeria. Methodology/Principal Findings Blood samples and ticks (Rhipicephalus sanguineus, Rhipicephalus turanicus and Heamaphysalis leachi) collected from 181 dogs from Nigeria were molecularly screened for human and animal vector-borne pathogens by PCR and sequencing. DNA of Hepatozoon canis (41.4%), Ehrlichia canis (12.7%), Rickettsia spp. (8.8%), Babesia rossi (6.6%), Anaplasma platys (6.6%), Babesia vogeli (0.6%) and Theileria sp. (0.6%) was detected in the blood samples. DNA of E. canis (23.7%), H. canis (21.1%), Rickettsia spp. (10.5%), Candidatus Neoehrlichia mikurensis (5.3%) and A. platys (1.9%) was detected in 258 ticks collected from 42 of the 181 dogs. Co- infections with two pathogens were present in 37% of the dogs examined and one dog was co-infected with 3 pathogens. DNA of Rickettsia conorii israelensis was detected in one dog and Rhipicephalus sanguineus tick. DNA of another human pathogen, Candidatus N. mikurensis was detected in Rhipicephalus sanguineus and Heamaphysalis leachi ticks, and is the first description of Candidatus N. mikurensis in Africa. The Theileria sp. DNA detected in a local dog in this study had 98% sequence identity to Theileria ovis from sheep. Conclusions/Significance The results of this study indicate that human and animal pathogens are abundant in dogs and their ticks in Nigeria and portray the potential high risk of human exposure to infection with these agents. PMID:23505591

  7. Molecular detection and characterization of tick-borne pathogens in dogs and ticks from Nigeria.

    Directory of Open Access Journals (Sweden)

    Joshua Kamani

    Full Text Available BACKGROUND: Only limited information is currently available on the prevalence of vector borne and zoonotic pathogens in dogs and ticks in Nigeria. The aim of this study was to use molecular techniques to detect and characterize vector borne pathogens in dogs and ticks from Nigeria. METHODOLOGY/PRINCIPAL FINDINGS: Blood samples and ticks (Rhipicephalus sanguineus, Rhipicephalus turanicus and Heamaphysalis leachi collected from 181 dogs from Nigeria were molecularly screened for human and animal vector-borne pathogens by PCR and sequencing. DNA of Hepatozoon canis (41.4%, Ehrlichia canis (12.7%, Rickettsia spp. (8.8%, Babesia rossi (6.6%, Anaplasma platys (6.6%, Babesia vogeli (0.6% and Theileria sp. (0.6% was detected in the blood samples. DNA of E. canis (23.7%, H. canis (21.1%, Rickettsia spp. (10.5%, Candidatus Neoehrlichia mikurensis (5.3% and A. platys (1.9% was detected in 258 ticks collected from 42 of the 181 dogs. Co- infections with two pathogens were present in 37% of the dogs examined and one dog was co-infected with 3 pathogens. DNA of Rickettsia conorii israelensis was detected in one dog and Rhipicephalus sanguineus tick. DNA of another human pathogen, Candidatus N. mikurensis was detected in Rhipicephalus sanguineus and Heamaphysalis leachi ticks, and is the first description of Candidatus N. mikurensis in Africa. The Theileria sp. DNA detected in a local dog in this study had 98% sequence identity to Theileria ovis from sheep. CONCLUSIONS/SIGNIFICANCE: The results of this study indicate that human and animal pathogens are abundant in dogs and their ticks in Nigeria and portray the potential high risk of human exposure to infection with these agents.

  8. Landscape variation influences trophic cascades in dengue vector food webs.

    Science.gov (United States)

    Weterings, Robbie; Umponstira, Chanin; Buckley, Hannah L

    2018-02-01

    The epidemiology of vector-borne diseases is governed by a structured array of correlative and causative factors, including landscape (for example, rural versus urban), abiotic (for example, weather), and biotic (for example, food web) factors. Studies of mosquito-borne diseases rarely address these multiple factors at large spatial scales, which limits insights into how human alterations of landscapes and food webs alter mosquito abundance. We used structural equation modeling to identify the relative magnitude and direction of landscape, abiotic, and food web factors on Aedes larvae and adults across 70 sites in northern Thailand. Food web factors were modeled as mosquito-predator trophic cascades. Landscape context affected mosquito-predator communities in aquatic and terrestrial environments via cascading food web interactions. Several mosquito predators within these food webs showed potential as biocontrol agents in mosquito population control, but their potentials for control were landscape-dependent. In terrestrial food webs, the habitat-sensitive tokay gecko structured mosquito-predator communities, indicating that a conservation approach to vector control could be a useful addition to existing control efforts.

  9. Violation of vector dominance in the vector manifestation

    International Nuclear Information System (INIS)

    Sasaki, Chihiro

    2003-01-01

    The vector manifestation (VM) is a new pattern for realizing the chiral symmetry in QCD. In the VM, the massless vector meson becomes the chiral partner of pion at the critical point, in contrast with the restoration based on the linear sigma model. Including the intrinsic temperature dependences of the parameters of the hidden local symmetry (HLS) Lagrangian determined from the underlying QCD through the Wilsonian matching together with the hadronic thermal corrections, we present a new prediction of the VM on the direct photon-π-π coupling which measures the validity of the vector dominance (VD) of the electromagnetic form factor of the pion. We find that the VD is largely violated at the critical temperature, which indicates that the assumption of the VD made in several analysis on the dilepton spectra in hot matter may need to be weakened for consistently including the effect of the dropping mass of the vector meson. (author)

  10. Estimating the temporal and spatial risk of bluetongue related to the incursion of infected vectors into Switzerland

    Directory of Open Access Journals (Sweden)

    Griot C

    2008-10-01

    Full Text Available Abstract Background The design of veterinary and public health surveillance systems has been improved by the ability to combine Geographical Information Systems (GIS, mathematical models and up to date epidemiological knowledge. In Switzerland, an early warning system was developed for detecting the incursion of the bluetongue disease virus (BT and to monitor the frequency of its vectors. Based on data generated by this surveillance system, GIS and transmission models were used in order to determine suitable seasonal vector habitat locations and risk periods for a larger and more targeted surveillance program. Results Combined thematic maps of temperature, humidity and altitude were created to visualize the association with Culicoides vector habitat locations. Additional monthly maps of estimated basic reproduction number transmission rates (R0 were created in order to highlight areas of Switzerland prone to higher BT outbreaks in relation to both vector activity and transmission levels. The maps revealed several foci of higher risk areas, especially in northern parts of Switzerland, suitable for both vector presence and vector activity for 2006. Results showed a variation of R0 values comparing 2005 and 2006 yet suggested that Switzerland was at risk of an outbreak of BT, especially if the incursion arrived in a suitable vector activity period. Since the time of conducting these analyses, this suitability has proved to be the case with the recent outbreaks of BT in northern Switzerland. Conclusion Our results stress the importance of environmental factors and their effect on the dynamics of a vector-borne disease. In this case, results of this model were used as input parameters for creating a national targeted surveillance program tailored to both the spatial and the temporal aspect of the disease and its vectors. In this manner, financial and logistic resources can be used in an optimal way through seasonally and geographically adjusted

  11. On the Witt vector Frobenius

    DEFF Research Database (Denmark)

    Davis, Christopher James; Kedlaya, Kiran

    2014-01-01

    We study the kernel and cokernel of the Frobenius map on the p-typical Witt vectors of a commutative ring, not necessarily of characteristic p. We give many equivalent conditions to surjectivity of the Frobenius map on both finite and infinite length Witt vectors. In particular, surjectivity...... on finite Witt vectors turns out to be stable under certain integral extensions; this provides a clean formulation of a strong generalization of Faltings’s almost purity theorem from p-adic Hodge theory, incorporating recent improvements by Kedlaya–Liu and by Scholze....

  12. Vector boson scattering at CLIC

    Energy Technology Data Exchange (ETDEWEB)

    Kilian, Wolfgang; Fleper, Christian [Department Physik, Universitaet Siegen, 57068 Siegen (Germany); Reuter, Juergen [DESY Theory Group, 22603 Hamburg (Germany); Sekulla, Marco [Institut fuer Theoretische Physik, Karlsruher Institut fuer Technologie, 76131 Karlsruhe (Germany)

    2016-07-01

    Linear colliders operating in a range of multiple TeV are able to investigate the details of vector boson scattering and electroweak symmetry breaking. We calculate cross sections with the Monte Carlo generator WHIZARD for vector boson scattering processes at the future linear e{sup +} e{sup -} collider CLIC. By finding suitable cuts, the vector boson scattering signal processes are isolated from the background. Finally, we are able to determine exclusion sensitivities on the non-Standard Model parameters of the relevant dimension eight operators.

  13. Vector control of induction machines

    CERN Document Server

    Robyns, Benoit

    2012-01-01

    After a brief introduction to the main law of physics and fundamental concepts inherent in electromechanical conversion, ""Vector Control of Induction Machines"" introduces the standard mathematical models for induction machines - whichever rotor technology is used - as well as several squirrel-cage induction machine vector-control strategies. The use of causal ordering graphs allows systematization of the design stage, as well as standardization of the structure of control devices. ""Vector Control of Induction Machines"" suggests a unique approach aimed at reducing parameter sensitivity for

  14. Recommendation on vectors and vector-transmitted diseases

    OpenAIRE

    Netherlands Food and Consumer Product Safety Authority

    2009-01-01

    In view of their increasing risk of introduction and their possible implications in causing major disease outbreaks, vectors, as well as vector-transmitted diseases like dengue, West Nile disease, Lyme disease and bluetongue need to be recognised as a threat to public and animal health and to the economy, also in the Netherlands. There has been an increase in the incidence of these diseases in the past two to three decades. Climate changes and changes in the use of land, water managemen...

  15. Vector manifestation and violation of vector dominance in hot matter

    International Nuclear Information System (INIS)

    Harada, Masayasu; Sasaki, Chihiro

    2004-01-01

    We show the details of the calculation of the hadronic thermal corrections to the two-point functions in the effective field theory of QCD for pions and vector mesons based on the hidden local symmetry (HLS) in hot matter using the background field gauge. We study the temperature dependence of the pion velocity in the low-temperature region determined from the hadronic thermal corrections, and show that, due to the presence of the dynamical vector meson, the pion velocity is smaller than the speed of the light already at one-loop level, in contrast to the result obtained in the ordinary chiral perturbation theory including only the pion at one-loop. Including the intrinsic temperature dependences of the parameters of the HLS Lagrangian determined from the underlying QCD through the Wilsonian matching, we show how the vector manifestation (VM), in which the massless vector meson becomes the chiral partner of pion, is realized at the critical temperature. We present a new prediction of the VM on the direct photon-π-π coupling which measures the validity of the vector dominance (VD) of the electromagnetic form factor of the pion: we find that the VD is largely violated at the critical temperature, which indicates that the assumption of the VD made in several analyses on the dilepton spectra in hot matter may need to be weakened for consistently including the effect of the dropping mass of the vector meson

  16. Plant-mediated synthesis of nanoparticles: A newer and safer tool against mosquito-borne diseases?

    Directory of Open Access Journals (Sweden)

    Giovanni Benelli

    2016-04-01

    Full Text Available Prevention and control of mosquito-borne diseases is a key challenge of huge public health importance. Plant-mediated synthesis of nanoparticles has recently gained attention as a cheap, rapid and eco-friendly method to control mosquito vector populations, with special reference to young instars. Furthermore, plant-fabricated nanoparticles have been successfully employed as dengue virus growth inhibitors. In this Editorial, parasitologists, entomologists and researchers in drug nanosynthesis are encouraged to deal with a number of crucial challenges of public health importance.

  17. Acquisition of Xyllela fastidiosa causes changes to the inoculation behavior (EPG X wave) of an efficient sharpshooter vector

    Science.gov (United States)

    Xylella fastidiosa (Xf) is a foregut-borne bacterium that is inoculated into xylem cells of a healthy plant during feeding by sharpshooter vectors. Inoculation occurs during salivation and egestion behaviors that are likely represented by the sharpshooter X wave. The objective of this study was to t...

  18. Quantification of vector and host competence and abundance for Japanese Encephalitis Virus: a systematic review of the literature.

    Science.gov (United States)

    Japanese encephalitis (JE) is a vector-borne disease caused by the Japanese encephalitis virus (JEV) that affects humans in Eastern and Southeastern Asia. Although it could be prevented by a vaccine, JE has no treatment and the inadvertent introduction of the virus into JEV-free countries, such as t...

  19. Vectorization at the KENO-IV code

    International Nuclear Information System (INIS)

    Asai, K.; Higuchi, K.; Katakura, J.

    1986-01-01

    The multigroup criticality safety code KENO-IV has been vectorized and tested on the FACOM VP-100 vector processor. At first, the vectorized KENO-IV on a scalar processor was slower than the original one by a factor of 1.4 because of the overhead introduced by vectorization. Making modifications of algorithms and techniques for vectorization, the vectorized version has become faster than the original one by a factor of 1.4 on the vector processor. For further speedup of the code, some improvements on compiler and hardware, especially on addition of Monte Carlo pipelines to the vector processor, are discussed

  20. Amblyomma cajennense is an intrastadial biological vector of Theileria equi.

    Science.gov (United States)

    Scoles, Glen A; Ueti, Massaro W

    2013-10-23

    The apicomplexan hemoprotozoan parasite Theileria equi is one of the etiologic agents causing equine piroplasmosis, a disease of equines that is endemic throughout large parts of the world. Before 2009 the United States had been considered to be free of this parasite. Occasional cases had occurred but there was no evidence for endemic vector-borne transmission in the U.S. until a 2009 outbreak in Texas in which Dermacentor variabilis and Amblyomma cajennense were implicated as vectors. Although D. variabilis has previously been shown to be a competent laboratory vector, studies suggested A. cajennense was not a competent transstadial vector, even though the presence of this tick species on horses in South American is epidemiologicaly correlated with higher a prevalence of infection. In this study we tested the transstadial and intrastadial vector competence of D. variabilis and A. cajennense for T. equi. A tick passaged T. equi strain from the Texas outbreak and ticks colonized from engorged females collected off horses on the outbreak ranch in Texas were used for these studies. Nymph or adult ticks were fed on infected horses and transmission fed on naïve horses. Infections were tracked with PCR and serology, dissected tick tissues were tested with PCR. A. cajennense transmitted T. equi intrastadially when adult ticks acquired infection by feeding on an infected horse, and transmitted to a naïve host on subsequent reattachment and feeding. D. variabilis failed to transmit in the same experiment. Transstadial transmission was not successful for either tick species. PCR on DNA isolated from eggs of females that had fed on an infected horse suggests that there is no transovarial passage of this parasite by either tick species. This work confirms that ticks from the Texas population of A. cajennense are competent intrastadial vectors of T. equi. We propose that the most likely natural mode of transmission for this parasite/vector combination in the Texas outbreak

  1. Scientific Discoveries the Year I Was Born

    Science.gov (United States)

    Cherif, Abour

    2012-01-01

    The author has successfully used a learning activity titled "The Year I Was Born" to motivate students to conduct historical research and present key scientific discoveries from their birth year. The activity promotes writing, helps students enhance their scientific literacy, and also improves their attitude toward the learning of science. As one…

  2. Testing Born-Infeld Electrodynamics in Waveguides

    International Nuclear Information System (INIS)

    Ferraro, Rafael

    2007-01-01

    Waveguides can be employed to test nonlinear effects in electrodynamics. We solve Born-Infeld equations for TE waves in a rectangular waveguide. We show that the energy velocity acquires a dependence on the amplitude, and harmonic components appear as a consequence of the nonlinear behavior

  3. Born with Protection against Whooping Cough

    Centers for Disease Control (CDC) Podcasts

    This podcast provides information about whooping cough, a disease that can be deadly for babies, and CDC’s recommendation that all women receive the Tdap vaccine during the third trimester of every pregnancy so their babies can be born with protection from this serious disease.

  4. Fortran code for generating random probability vectors, unitaries, and quantum states

    Directory of Open Access Journals (Sweden)

    Jonas eMaziero

    2016-03-01

    Full Text Available The usefulness of generating random configurations is recognized in many areas of knowledge. Fortran was born for scientific computing and has been one of the main programming languages in this area since then. And several ongoing projects targeting towards its betterment indicate that it will keep this status in the decades to come. In this article, we describe Fortran codes produced, or organized, for the generation of the following random objects: numbers, probability vectors, unitary matrices, and quantum state vectors and density matrices. Some matrix functions are also included and may be of independent interest.

  5. Introduction to matrices and vectors

    CERN Document Server

    Schwartz, Jacob T

    2001-01-01

    In this concise undergraduate text, the first three chapters present the basics of matrices - in later chapters the author shows how to use vectors and matrices to solve systems of linear equations. 1961 edition.

  6. GRE Enzymes for Vector Analysis

    Data.gov (United States)

    U.S. Environmental Protection Agency — Microbial enzyme data that were collected during the 2004-2006 EMAP-GRE program. These data were then used by Moorhead et al (2016) in their ecoenzyme vector...

  7. Scanning vector Hall probe microscopy

    International Nuclear Information System (INIS)

    Cambel, V.; Gregusova, D.; Fedor, J.; Kudela, R.; Bending, S.J.

    2004-01-01

    We have developed a scanning vector Hall probe microscope for mapping magnetic field vector over magnetic samples. The microscope is based on a micromachined Hall sensor and the cryostat with scanning system. The vector Hall sensor active area is ∼5x5 μm 2 . It is realized by patterning three Hall probes on the tilted faces of GaAs pyramids. Data from these 'tilted' Hall probes are used to reconstruct the full magnetic field vector. The scanning area of the microscope is 5x5 mm 2 , space resolution 2.5 μm, field resolution ∼1 μT Hz -1/2 at temperatures 10-300 K

  8. 3D vector flow imaging

    DEFF Research Database (Denmark)

    Pihl, Michael Johannes

    The main purpose of this PhD project is to develop an ultrasonic method for 3D vector flow imaging. The motivation is to advance the field of velocity estimation in ultrasound, which plays an important role in the clinic. The velocity of blood has components in all three spatial dimensions, yet...... are (vx, vy, vz) = (-0.03, 95, 1.0) ± (9, 6, 1) cm/s compared with the expected (0, 96, 0) cm/s. Afterwards, 3D vector flow images from a cross-sectional plane of the vessel are presented. The out of plane velocities exhibit the expected 2D circular-symmetric parabolic shape. The experimental results...... verify that the 3D TO method estimates the complete 3D velocity vectors, and that the method is suitable for 3D vector flow imaging....

  9. 3-D Vector Flow Imaging

    DEFF Research Database (Denmark)

    Holbek, Simon

    , if this significant reduction in the element count can still provide precise and robust 3-D vector flow estimates in a plane. The study concludes that the RC array is capable of estimating precise 3-D vector flow both in a plane and in a volume, despite the low channel count. However, some inherent new challenges...... ultrasonic vector flow estimation and bring it a step closer to a clinical application. A method for high frame rate 3-D vector flow estimation in a plane using the transverse oscillation method combined with a 1024 channel 2-D matrix array is presented. The proposed method is validated both through phantom...... hampers the task of real-time processing. In a second study, some of the issue with the 2-D matrix array are solved by introducing a 2-D row-column (RC) addressing array with only 62 + 62 elements. It is investigated both through simulations and via experimental setups in various flow conditions...

  10. Transcriptional Silencing of Retroviral Vectors

    DEFF Research Database (Denmark)

    Lund, Anders Henrik; Duch, M.; Pedersen, F.S.

    1996-01-01

    . Extinction of long-term vector expression has been observed after implantation of transduced hematopoietic cells as well as fibroblasts, myoblasts and hepatocytes. Here we review the influence of vector structure, integration site and cell type on transcriptional silencing. While down-regulation of proviral...... transcription is known from a number of cellular and animal models, major insight has been gained from studies in the germ line and embryonal cells of the mouse. Key elements for the transfer and expression of retroviral vectors, such as the viral transcriptional enhancer and the binding site for the t......RNA primer for reverse transcription may have a major influence on transcriptional silencing. Alterations of these elements of the vector backbone as well as the use of internal promoter elements from housekeeping genes may contribute to reduce transcriptional silencing. The use of cell culture and animal...

  11. High Accuracy Vector Helium Magnetometer

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed HAVHM instrument is a laser-pumped helium magnetometer with both triaxial vector and omnidirectional scalar measurement capabilities in a single...

  12. The importance of being urgent: The impact of surveillance target and scale on mosquito-borne disease control

    Directory of Open Access Journals (Sweden)

    Samantha R. Schwab

    2018-06-01

    Full Text Available With the emergence or re-emergence of numerous mosquito-borne diseases in recent years, effective methods for emergency vector control responses are necessary to reduce human infections. Current vector control practices often vary significantly between different jurisdictions, and are executed independently and at different spatial scales. Various types of surveillance information (e.g. number of human infections or adult mosquitoes trigger the implementation of control measures, though the target and scale of surveillance vary locally. This patchy implementation of control measures likely alters the efficacy of control.We modeled six different scenarios, with larval mosquito control occurring in response to surveillance data of different types and at different scales (e.g. across the landscape or in each patch. Our results indicate that: earlier application of larvicide after an escalation of disease risk achieves much greater reductions in human infections than later control implementation; uniform control across the landscape provides better outbreak mitigation than patchy control application; and different types of surveillance data require different levels of sensitivity in their collection to effectively inform control measures. Our simulations also demonstrate a potential logical fallacy of reactive, surveillance-driven vector control: measures stop being implemented as soon as they are deemed effective. This false sense of security leads to patchier control efforts that will do little to curb the size of future vector-borne disease outbreaks. More investment should be placed in collecting high quality information that can trigger early and uniform implementation, while researchers work to discover more informative metrics of human risk to trigger more effective control. Keywords: Zika control, Epidemiological surveillance, Disease surveillance, Mosquito control, Vector-borne disease control, Epidemiological modeling

  13. An exotic composite vector boson

    International Nuclear Information System (INIS)

    Akama, Keiichi; Hattori, Takashi; Yasue, Masaki.

    1990-08-01

    An exotic composite vector boson, V, is introduced in two dynamical models of composite quarks, leptons, W and Z. One is based on four Fermi interactions, in which composite vector bosons are regarded as fermion-antifermion bound states and the other is based on the confining SU(2) L gauge model, in which they are given by scalar-antiscalar bound states. Both approaches describe the same effective interactions for the sector of composite quarks, leptons, W, Z, γ and V. (author)

  14. A Roadmap for Tick-Borne Flavivirus Research in the “Omics” Era

    Directory of Open Access Journals (Sweden)

    Jeffrey M. Grabowski

    2017-12-01

    Full Text Available Tick-borne flaviviruses (TBFs affect human health globally. Human vaccines provide protection against some TBFs, and antivirals are available, yet TBF-specific control strategies are limited. Advances in genomics offer hope to understand the viral complement transmitted by ticks, and to develop disruptive, data-driven technologies for virus detection, treatment, and control. The genome assemblies of Ixodes scapularis, the North American tick vector of the TBF, Powassan virus, and other tick vectors, are providing insights into tick biology and pathogen transmission and serve as nucleation points for expanded genomic research. Systems biology has yielded insights to the response of tick cells to viral infection at the transcript and protein level, and new protein targets for vaccines to limit virus transmission. Reverse vaccinology approaches have moved candidate tick antigenic epitopes into vaccine development pipelines. Traditional drug and in silico screening have identified candidate antivirals, and target-based approaches have been developed to identify novel acaricides. Yet, additional genomic resources are required to expand TBF research. Priorities include genome assemblies for tick vectors, “omic” studies involving high consequence pathogens and vectors, and emphasizing viral metagenomics, tick-virus metabolomics, and structural genomics of TBF and tick proteins. Also required are resources for forward genetics, including the development of tick strains with quantifiable traits, genetic markers and linkage maps. Here we review the current state of genomic research on ticks and tick-borne viruses with an emphasis on TBFs. We outline an ambitious 10-year roadmap for research in the “omics era,” and explore key milestones needed to accomplish the goal of delivering three new vaccines, antivirals and acaricides for TBF control by 2030.

  15. Palatini approach to Born-Infeld-Einstein theory and a geometric description of electrodynamics

    International Nuclear Information System (INIS)

    Vollick, Dan N.

    2004-01-01

    The field equations associated with the Born-Infeld-Einstein action are derived using the Palatini variational technique. In this approach the metric and connection are varied independently and the Ricci tensor is generally not symmetric. For sufficiently small curvatures the resulting field equations can be divided into two sets. One set, involving the antisymmetric part of the Ricci tensor R or μν , consists of the field equation for a massive vector field. The other set consists of the Einstein field equations with an energy momentum tensor for the vector field plus additional corrections. In a vacuum with R or μν =0 the field equations are shown to be the usual Einstein vacuum equations. This extends the universality of the vacuum Einstein equations, discussed by Ferraris et al., to the Born-Infeld-Einstein action. In the simplest version of the theory there is a single coupling constant and by requiring that the Einstein field equations hold to a good approximation in neutron stars it is shown that mass of the vector field exceeds the lower bound on the mass of the photon. Thus, in this case the vector field cannot represent the electromagnetic field and would describe a new geometrical field. In a more general version in which the symmetric and antisymmetric parts of the Ricci tensor have different coupling constants it is possible to satisfy all of the observational constraints if the antisymmetric coupling is much larger than the symmetric coupling. In this case the antisymmetric part of the Ricci tensor can describe the electromagnetic field

  16. Joint Laxity in Preschool Children Born Preterm.

    Science.gov (United States)

    Romeo, Domenico M; Velli, Chiara; Lucibello, Simona; Ferrantini, Gloria; Leo, Giuseppina; Brogna, Claudia; Cota, Francesco; Ricci, Daniela; Gallini, Francesca; Romagnoli, Costantino; Vento, Giovanni; Mercuri, Eugenio

    2018-06-01

    To evaluate the prevalence of joint laxity in children born preterm assessed in the first 2 years, the relationship between joint laxity and motor performance at preschool age, and possible changes over time in a subgroup of children followed longitudinally. The revised scale of Beighton Score was used to evaluate joint laxity in a population of 132 preschool children born preterm between 24 and 32 weeks of gestational age. All were assessed for joint laxity between 12 and 24 months of age. Children also performed the Movement Assessment Battery for Children-Second Edition between the age of 3 years and 6 months and 4 years; the age at onset of independent walking also was recorded. The total Beighton Score ranged between 0 and 8. Twenty percent of the cohort showed joint laxity. No differences related to sex or gestational age were observed. Children born preterm with joint laxity achieved later independent walking and achieved lower scores on Movement Assessment Battery for Children-Second Edition than those without joint laxity. In 76 children born preterm, an assessment for joint laxity was repeated once between 25 and 36 months and again after >36 months. No statistically significant difference was observed between the 3 assessments. The Beighton Score can be used to assess generalized joint laxity in children born preterm. As the presence of joint laxity influenced motor competences, the possibility to early identify these infants in the first 2 years is of interest to benefit from early intervention and potentially improve gross motor skills and coordination. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. An economic evaluation of vector control in the age of a dengue vaccine.

    Science.gov (United States)

    Fitzpatrick, Christopher; Haines, Alexander; Bangert, Mathieu; Farlow, Andrew; Hemingway, Janet; Velayudhan, Raman

    2017-08-01

    Dengue is a rapidly emerging vector-borne Neglected Tropical Disease, with a 30-fold increase in the number of cases reported since 1960. The economic cost of the illness is measured in the billions of dollars annually. Environmental change and unplanned urbanization are conspiring to raise the health and economic cost even further beyond the reach of health systems and households. The health-sector response has depended in large part on control of the Aedes aegypti and Ae. albopictus (mosquito) vectors. The cost-effectiveness of the first-ever dengue vaccine remains to be evaluated in the field. In this paper, we examine how it might affect the cost-effectiveness of sustained vector control. We employ a dynamic Markov model of the effects of vector control on dengue in both vectors and humans over a 15-year period, in six countries: Brazil, Columbia, Malaysia, Mexico, the Philippines, and Thailand. We evaluate the cost (direct medical costs and control programme costs) and cost-effectiveness of sustained vector control, outbreak response and/or medical case management, in the presence of a (hypothetical) highly targeted and low cost immunization strategy using a (non-hypothetical) medium-efficacy vaccine. Sustained vector control using existing technologies would cost little more than outbreak response, given the associated costs of medical case management. If sustained use of existing or upcoming technologies (of similar price) reduce vector populations by 70-90%, the cost per disability-adjusted life year averted is 2013 US$ 679-1331 (best estimates) relative to no intervention. Sustained vector control could be highly cost-effective even with less effective technologies (50-70% reduction in vector populations) and in the presence of a highly targeted and low cost immunization strategy using a medium-efficacy vaccine. Economic evaluation of the first-ever dengue vaccine is ongoing. However, even under very optimistic assumptions about a highly targeted and low

  18. An economic evaluation of vector control in the age of a dengue vaccine.

    Directory of Open Access Journals (Sweden)

    Christopher Fitzpatrick

    2017-08-01

    Full Text Available Dengue is a rapidly emerging vector-borne Neglected Tropical Disease, with a 30-fold increase in the number of cases reported since 1960. The economic cost of the illness is measured in the billions of dollars annually. Environmental change and unplanned urbanization are conspiring to raise the health and economic cost even further beyond the reach of health systems and households. The health-sector response has depended in large part on control of the Aedes aegypti and Ae. albopictus (mosquito vectors. The cost-effectiveness of the first-ever dengue vaccine remains to be evaluated in the field. In this paper, we examine how it might affect the cost-effectiveness of sustained vector control.We employ a dynamic Markov model of the effects of vector control on dengue in both vectors and humans over a 15-year period, in six countries: Brazil, Columbia, Malaysia, Mexico, the Philippines, and Thailand. We evaluate the cost (direct medical costs and control programme costs and cost-effectiveness of sustained vector control, outbreak response and/or medical case management, in the presence of a (hypothetical highly targeted and low cost immunization strategy using a (non-hypothetical medium-efficacy vaccine.Sustained vector control using existing technologies would cost little more than outbreak response, given the associated costs of medical case management. If sustained use of existing or upcoming technologies (of similar price reduce vector populations by 70-90%, the cost per disability-adjusted life year averted is 2013 US$ 679-1331 (best estimates relative to no intervention. Sustained vector control could be highly cost-effective even with less effective technologies (50-70% reduction in vector populations and in the presence of a highly targeted and low cost immunization strategy using a medium-efficacy vaccine.Economic evaluation of the first-ever dengue vaccine is ongoing. However, even under very optimistic assumptions about a highly targeted

  19. Vectoring of parallel synthetic jets

    Science.gov (United States)

    Berk, Tim; Ganapathisubramani, Bharathram; Gomit, Guillaume

    2015-11-01

    A pair of parallel synthetic jets can be vectored by applying a phase difference between the two driving signals. The resulting jet can be merged or bifurcated and either vectored towards the actuator leading in phase or the actuator lagging in phase. In the present study, the influence of phase difference and Strouhal number on the vectoring behaviour is examined experimentally. Phase-locked vorticity fields, measured using Particle Image Velocimetry (PIV), are used to track vortex pairs. The physical mechanisms that explain the diversity in vectoring behaviour are observed based on the vortex trajectories. For a fixed phase difference, the vectoring behaviour is shown to be primarily influenced by pinch-off time of vortex rings generated by the synthetic jets. Beyond a certain formation number, the pinch-off timescale becomes invariant. In this region, the vectoring behaviour is determined by the distance between subsequent vortex rings. We acknowledge the financial support from the European Research Council (ERC grant agreement no. 277472).

  20. Versatile generation of optical vector fields and vector beams using a non-interferometric approach.

    Science.gov (United States)

    Tripathi, Santosh; Toussaint, Kimani C

    2012-05-07

    We present a versatile, non-interferometric method for generating vector fields and vector beams which can produce all the states of polarization represented on a higher-order Poincaré sphere. The versatility and non-interferometric nature of this method is expected to enable exploration of various exotic properties of vector fields and vector beams. To illustrate this, we study the propagation properties of some vector fields and find that, in general, propagation alters both their intensity and polarization distribution, and more interestingly, converts some vector fields into vector beams. In the article, we also suggest a modified Jones vector formalism to represent vector fields and vector beams.