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  1. The evolutionary rate dynamically tracks changes in HIV-1 epidemics

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    Maljkovic-berry, Irina [Los Alamos National Laboratory; Athreya, Gayathri [Los Alamos National Laboratory; Daniels, Marcus [Los Alamos National Laboratory; Bruno, William [Los Alamos National Laboratory; Korber, Bette [Los Alamos National Laboratory; Kuiken, Carla [Los Alamos National Laboratory; Ribeiro, Ruy M [Los Alamos National Laboratory

    2009-01-01

    Large-sequence datasets provide an opportunity to investigate the dynamics of pathogen epidemics. Thus, a fast method to estimate the evolutionary rate from large and numerous phylogenetic trees becomes necessary. Based on minimizing tip height variances, we optimize the root in a given phylogenetic tree to estimate the most homogenous evolutionary rate between samples from at least two different time points. Simulations showed that the method had no bias in the estimation of evolutionary rates and that it was robust to tree rooting and topological errors. We show that the evolutionary rates of HIV-1 subtype B and C epidemics have changed over time, with the rate of evolution inversely correlated to the rate of virus spread. For subtype B, the evolutionary rate slowed down and tracked the start of the HAART era in 1996. Subtype C in Ethiopia showed an increase in the evolutionary rate when the prevalence increase markedly slowed down in 1995. Thus, we show that the evolutionary rate of HIV-1 on the population level dynamically tracks epidemic events.

  2. The role of recombination in the emergence of a complex and dynamic HIV epidemic

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    Morgenstern Burkhard

    2010-03-01

    Full Text Available Abstract Background Inter-subtype recombinants dominate the HIV epidemics in three geographical regions. To better understand the role of HIV recombinants in shaping the current HIV epidemic, we here present the results of a large-scale subtyping analysis of 9435 HIV-1 sequences that involve subtypes A, B, C, G, F and the epidemiologically important recombinants derived from three continents. Results The circulating recombinant form CRF02_AG, common in West Central Africa, appears to result from recombination events that occurred early in the divergence between subtypes A and G, followed by additional recent recombination events that contribute to the breakpoint pattern defining the current recombinant lineage. This finding also corrects a recent claim that G is a recombinant and a descendant of CRF02, which was suggested to be a pure subtype. The BC and BF recombinants in China and South America, respectively, are derived from recent recombination between contemporary parental lineages. Shared breakpoints in South America BF recombinants indicate that the HIV-1 epidemics in Argentina and Brazil are not independent. Therefore, the contemporary HIV-1 epidemic has recombinant lineages of both ancient and more recent origins. Conclusions Taken together, we show that these recombinant lineages, which are highly prevalent in the current HIV epidemic, are a mixture of ancient and recent recombination. The HIV pandemic is moving towards having increasing complexity and higher prevalence of recombinant forms, sometimes existing as "families" of related forms. We find that the classification of some CRF designations need to be revised as a consequence of (1 an estimated > 5% error in the original subtype assignments deposited in the Los Alamos sequence database; (2 an increasing number of CRFs are defined while they do not readily fit into groupings for molecular epidemiology and vaccine design; and (3 a dynamic HIV epidemic context.

  3. Global HIV/AIDS Epidemic

    Science.gov (United States)

    ... Policy The Global HIV/AIDS Epidemic The Global HIV/AIDS Epidemic Published: Nov 29, 2017 Facebook Twitter ... 2001-FY 2018 Request The Global Response to HIV/AIDS International efforts to combat HIV began in ...

  4. Gender inequality dynamics in the prevention of a heterosexual HIV epidemic in sub-Saharan Africa.

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    Wathuta, Jane

    2016-01-01

    This paper critiques the approach to the elimination of gender inequality as an HIV prevention strategy in the just ended era of the Millennium Development Goals, with the aim of contributing to the formulation of policy guidelines for sub-Saharan Africa in the Sustainable Development Goals. The aim is to underscore the mutual responsibility of women and men in achieving a sustainable HIV response and ending the epidemic. While taking into account the real vulnerability of women, prevention programmes can reflect gender dynamics more accurately so that attention is given to the role of both sexes in propagating - or stemming - a predominantly heterosexual HIV epidemic. More emphasis could be given to the harm caused to both men and women by certain norms related to masculinity and sexuality, and the subsequent need for combined efforts in reducing intimate partner violence and concurrency. The empowerment and engagement of both women and men as agents of change would need to be dealt with more creatively.

  5. Emergence of recombinant forms in geographic regions with co-circulating HIV subtypes in the dynamic HIV-1 epidemic

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    Zhang, Ming [Los Alamos National Laboratory; Letiner, Thomas K [Los Alamos National Laboratory; Korber, Bette T [Los Alamos National Laboratory; Foley, Brian [Los Alamos National Laboratory

    2009-01-01

    We have reexamined the subtype designations of {approx}10,000 subtype A, B, C, G, and AG, BC, BF recombinant sequences, and compared the results of the new analysis with their published designations. Intersubtype recombinants dominate HIV epidemics in three different geographical regions. The circulating recombinant from (CRF) CRF02-AG, common in West Central Africa, appears to result from a recombination event that occurred early in the divergence between subtypes A and G, although additional more recent recombination events may have contributed to the breakpoint pattern in this recombinant lineage as well. The Chinese recombinant epidemic strains CRF07 and CRF08, in contrast, result from recent recombinations between more contemporary strains. Nevertheless, CRF07 and CRF08 contributed to many subsequent recombination events. The BF recombinant epidemics in two HIV-1 epicenters in South America are not independent and BF epidemics in South America have an unusually high fraction of unique recombinant forms (URFs) that have each been found only once and carry distinctive breakpoints. Taken together, these analyses reveal a complex and dynamic picture of the current HIV-1 epidemic, and suggest a means of grouping and tracking relationships between viruses through preservation of shared breakpints.

  6. Phylodynamic analysis of HIV sub-epidemics in Mochudi, Botswana

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    Vlad Novitsky

    2015-12-01

    Real-time HIV genotyping and breaking down local HIV epidemics into phylogenetically distinct sub-epidemics may help to reveal the structure and dynamics of HIV transmission networks in communities, and aid in the design of targeted interventions for members of the acute sub-epidemics that likely fuel local HIV/AIDS epidemics.

  7. The dispersion of age differences between partners and the asymptotic dynamics of the HIV epidemic.

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    d'Albis, Hippolyte; Augeraud-Véron, Emmanuelle; Djemai, Elodie; Ducrot, Arnaud

    2012-01-01

    In this paper, the effect of a change in the distribution of age differences between sexual partners on the dynamics of the HIV epidemic is studied. In a gender- and age-structured compartmental model, it is shown that if the variance of the distribution is small enough, an increase in this variance strongly increases the basic reproduction number. Moreover, if the variance is large enough, the mean age difference barely affects the basic reproduction number. We, therefore, conclude that the local stability of the disease-free equilibrium relies more on the variance than on the mean.

  8. Phylogenetic studies of transmission dynamics in generalized HIV epidemics: An essential tool where the burden is greatest?

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    Dennis, Ann M.; Herbeck, Joshua T.; Brown, Andrew Leigh; Kellam, Paul; de Oliveira, Tulio; Pillay, Deenan; Fraser, Christophe; Cohen, Myron S.

    2014-01-01

    Efficient and effective HIV prevention measures for generalized epidemics in sub-Saharan Africa have not yet been validated at the population-level. Design and impact evaluation of such measures requires fine-scale understanding of local HIV transmission dynamics. The novel tools of HIV phylogenetics and molecular epidemiology may elucidate these transmission dynamics. Such methods have been incorporated into studies of concentrated HIV epidemics to identify proximate and determinant traits associated with ongoing transmission. However, applying similar phylogenetic analyses to generalized epidemics, including the design and evaluation of prevention trials, presents additional challenges. Here we review the scope of these methods and present examples of their use in concentrated epidemics in the context of prevention. Next, we describe the current uses for phylogenetics in generalized epidemics, and discuss their promise for elucidating transmission patterns and informing prevention trials. Finally, we review logistic and technical challenges inherent to large-scale molecular epidemiological studies of generalized epidemics, and suggest potential solutions. PMID:24977473

  9. Spatiotemporal dynamics of the HIV-1 subtype G epidemic in West and Central Africa.

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    Delatorre, Edson; Mir, Daiana; Bello, Gonzalo

    2014-01-01

    The human immunodeficiency virus type 1 (HIV-1) subtype G is the second most prevalent HIV-1 clade in West Africa, accounting for nearly 30% of infections in the region. There is no information about the spatiotemporal dynamics of dissemination of this HIV-1 clade in Africa. To this end, we analyzed a total of 305 HIV-1 subtype G pol sequences isolated from 11 different countries from West and Central Africa over a period of 20 years (1992 to 2011). Evolutionary, phylogeographic and demographic parameters were jointly estimated from sequence data using a Bayesian coalescent-based method. Our analyses indicate that subtype G most probably emerged in Central Africa in 1968 (1956-1976). From Central Africa, the virus was disseminated to West and West Central Africa at multiple times from the middle 1970s onwards. Two subtype G strains probably introduced into Nigeria and Togo between the middle and the late 1970s were disseminated locally and to neighboring countries, leading to the origin of two major western African clades (G WA-I and G WA-II). Subtype G clades circulating in western and central African regions displayed an initial phase of exponential growth followed by a decline in growth rate since the early/middle 1990 s; but the mean epidemic growth rate of G WA-I (0.75 year-1) and G WA-II (0.95 year-1) clades was about two times higher than that estimated for central African lineages (0.47 year-1). Notably, the overall evolutionary and demographic history of G WA-I and G WA-II clades was very similar to that estimated for the CRF06_cpx clade circulating in the same region. These results support the notion that the spatiotemporal dissemination dynamics of major HIV-1 clades circulating in western Africa have probably been shaped by the same ecological factors.

  10. Short-Term Dynamic and Local Epidemiological Trends in the South American HIV-1B Epidemic.

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    Dennis Maletich Junqueira

    Full Text Available The human displacement and sexual behavior are the main factors driving the HIV-1 pandemic to the current profile. The intrinsic structure of the HIV transmission among different individuals has valuable importance for the understanding of the epidemic and for the public health response. The aim of this study was to characterize the HIV-1 subtype B (HIV-1B epidemic in South America through the identification of transmission links and infer trends about geographical patterns and median time of transmission between individuals. Sequences of the protease and reverse transcriptase coding regions from 4,810 individuals were selected from GenBank. Maximum likelihood phylogenies were inferred and submitted to ClusterPicker to identify transmission links. Bayesian analyses were applied only for clusters including ≥5 dated samples in order to estimate the median maximum inter-transmission interval. This study analyzed sequences sampled from 12 South American countries, from individuals of different exposure categories, under different antiretroviral profiles, and from a wide period of time (1989-2013. Continentally, Brazil, Argentina and Venezuela were revealed important sites for the spread of HIV-1B among countries inside South America. Of note, from all the clusters identified about 70% of the HIV-1B infections are primarily occurring among individuals living in the same geographic region. In addition, these transmissions seem to occur early after the infection of an individual, taking in average 2.39 years (95% CI 1.48-3.30 to succeed. Homosexual/Bisexual individuals transmit the virus as quickly as almost half time of that estimated for the general population sampled here. Public health services can be broadly benefitted from this kind of information whether to focus on specific programs of response to the epidemic whether as guiding of prevention campaigns to specific risk groups.

  11. Short-Term Dynamic and Local Epidemiological Trends in the South American HIV-1B Epidemic.

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    Junqueira, Dennis Maletich; de Medeiros, Rubia Marília; Gräf, Tiago; Almeida, Sabrina Esteves de Matos

    2016-01-01

    The human displacement and sexual behavior are the main factors driving the HIV-1 pandemic to the current profile. The intrinsic structure of the HIV transmission among different individuals has valuable importance for the understanding of the epidemic and for the public health response. The aim of this study was to characterize the HIV-1 subtype B (HIV-1B) epidemic in South America through the identification of transmission links and infer trends about geographical patterns and median time of transmission between individuals. Sequences of the protease and reverse transcriptase coding regions from 4,810 individuals were selected from GenBank. Maximum likelihood phylogenies were inferred and submitted to ClusterPicker to identify transmission links. Bayesian analyses were applied only for clusters including ≥5 dated samples in order to estimate the median maximum inter-transmission interval. This study analyzed sequences sampled from 12 South American countries, from individuals of different exposure categories, under different antiretroviral profiles, and from a wide period of time (1989-2013). Continentally, Brazil, Argentina and Venezuela were revealed important sites for the spread of HIV-1B among countries inside South America. Of note, from all the clusters identified about 70% of the HIV-1B infections are primarily occurring among individuals living in the same geographic region. In addition, these transmissions seem to occur early after the infection of an individual, taking in average 2.39 years (95% CI 1.48-3.30) to succeed. Homosexual/Bisexual individuals transmit the virus as quickly as almost half time of that estimated for the general population sampled here. Public health services can be broadly benefitted from this kind of information whether to focus on specific programs of response to the epidemic whether as guiding of prevention campaigns to specific risk groups.

  12. Impact of the HIV epidemic on population and household structure: the dynamics and evidence to date.

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    Heuveline, Patrick

    2004-06-01

    HIV is contracted most frequently at birth and during early adulthood. The epidemic may thus impact the demographic structure and the household structure of affected populations. This paper reviews earlier evidence of such an impact, uses demographic theory to anticipate its changes over time, and reviews the most recent evidence for indications of these changes. Modest increases in the male : female ratio are beginning to show within certain age groups only (approximately 15% among 25-34 year olds). Similarly sized increases in the proportion of 15-29 year olds relative to 30-54 year olds are observed in some age pyramids. These 'youth bulges' are expected to fade out, whereas an aging effect phases in with the fertility impact of the epidemic. In the longer run, the size of all age groups will be reduced, but relatively less so for middle-aged adults. Proportions of orphans and widows have increased in the most affected countries. Fewer remarriage probabilities for widows were observed. Resulting increases in the proportion of female-headed households should only be temporary, as female mortality is catching up with male mortality. The number of double orphans is beginning to increase, but overall, orphans continue to live predominantly with a family member, most often the grandparents if not with the surviving parent. To date, the epidemic's impact on the population and household structure has been limited by demographic (aging) and social (adaptive movements of kin across households) processes that contribute to diffuse the epidemic throughout the entire population and all households.

  13. Concurrency can drive an HIV epidemic by moving R0 across the epidemic threshold

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    Leung, Ka Yin; Kretzschmar, Mirjam

    2015-01-01

    OBJECTIVE: The objective of this study is to investigate whether concurrency can drive an HIV epidemic by moving R0 across the epidemic threshold. DESIGN AND METHODS: We use a mathematical framework for a dynamic partnership network and the spread of a one-stage infection to study how concurrency is

  14. Population dynamics of HIV-2 in rural West Africa: comparison with HIV-1 and ongoing transmission at the heart of the epidemic

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    de Silva, Thushan I.; van Tienen, Carla; Onyango, Clayton; Jabang, Abdoulie; Vincent, Tim; Loeff, Maarten F. Schim van der; Coutinho, Roel A.; Jaye, Assan; Rowland-Jones, Sarah; Whittle, Hilton; Cotten, Matthew; Hué, Stéphane

    2013-01-01

    To compare the population dynamics of HIV-2 and HIV-1, and to characterize ongoing HIV-2 transmission in rural Guinea-Bissau. Phylogenetic and phylodynamic analyses using HIV-2 gag and env, and HIV-1 env sequences, combined with epidemiological data from a community cohort. Samples were obtained

  15. Phylogenetics of the Danish HIV epidemic

    DEFF Research Database (Denmark)

    Audelin, Anne Margrethe; Cowan, Susan A; Obel, Niels

    2013-01-01

    BACKGROUND:: In Denmark 300 new individuals are diagnosed with HIV every year, despite decades of public health campaigns aimed to raise awareness of potential risk behaviour for HIV transmission. It is important to identify the driving forces of the epidemic, to enable more targeted campaigns...

  16. Monitoring linked epidemics: the case of tuberculosis and HIV.

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    María S Sánchez

    Full Text Available BACKGROUND: The tight epidemiological coupling between HIV and its associated opportunistic infections leads to challenges and opportunities for disease surveillance. METHODOLOGY/PRINCIPAL FINDINGS: We review efforts of WHO and collaborating agencies to track and fight the TB/HIV co-epidemic, and discuss modeling--via mathematical, statistical, and computational approaches--as a means to identify disease indicators designed to integrate data from linked diseases in order to characterize how co-epidemics change in time and space. We present R(TB/HIV, an index comparing changes in TB incidence relative to HIV prevalence, and use it to identify those sub-Saharan African countries with outlier TB/HIV dynamics. R(TB/HIV can also be used to predict epidemiological trends, investigate the coherency of reported trends, and cross-check the anticipated impact of public health interventions. Identifying the cause(s responsible for anomalous R(TB/HIV values can reveal information crucial to the management of public health. CONCLUSIONS/SIGNIFICANCE: We frame our suggestions for integrating and analyzing co-epidemic data within the context of global disease monitoring. Used routinely, joint disease indicators such as R(TB/HIV could greatly enhance the monitoring and evaluation of public health programs.

  17. HIV epidemics in Shenzhen and Chongqing, China.

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    Shu Yang

    Full Text Available Men who have sex with men (MSM and heterosexuals are the populations with the fastest growing HIV infection rates in China. We characterize the epidemic growth and age patterns between these two routes from 2004 to 2015 in Chongqing and Shenzhen, China.Data were downloaded from the National HIV/ AIDS Comprehensive Response Information Management System. For the new HIV diagnoses of heterosexuals and MSM in both cities, we estimated the growth rates by fitting different sub-exponential models. Heat maps are used to show their age patterns. We used histograms to compare these patterns by birth cohort.The MSM epidemics grew significantly in both cities. Chongqing experienced quadratic growth in HIV reported cases with an estimated growth rate of 0.086 per week and a "deceleration rate" of 0.673. HIV reported cases of MSM in Shenzhen grew even more drastically with a growth rate of 0.033 per week and "deceleration rate" of 0.794. The new infections are mainly affecting the ages of 18 to 30 in Chongqing and ages of 20 to 35 in Shenzhen. They peaked in early 1990's and mid-1990's birth cohorts in Chongqing and Shenzhen respectively. The HIV epidemic among heterosexuals grew rapidly in both cities. The growth rates were estimated as 0.02 and 0.028 in Chongqing and Shenzhen respectively whereas the "deceleration rates" were 0.878 and 0.790 in these two places. It affected mostly aged 18 to 75 in males and 18 to 65 in females in Chongqing and aged 18 to 45 in males and 18 to 50 in females in Shenzhen in 2015. In Chongqing, the heterosexual female epidemics display two peaks in HIV diagnoses in the birth cohorts of early 1950's and early 1980's, with heterosexual male epidemics peaked in early 1940's and early 1960's. The heterosexual male and female epidemics display higher rates in the birth cohort 1940-1960, than the birth cohort 1960-1990. It peaked in birth cohorts of 1950's and 1980's in Shenzhen.We revealed striking differences in epidemic growth

  18. the south african hiv epidemic, reflected by nine provincial ...

    African Journals Online (AJOL)

    the distribution and trend of the HIV epidemic in each of the ... The exponential model significantly explains the HIV epidemics in the .... such a curve is considered to be made up of three. October 199 ..... Ut: Quantitative Forecasting Methods.

  19. HIV epidemic in South Africa: A comparison of HIV epidemic ...

    African Journals Online (AJOL)

    2014-08-26

    Aug 26, 2014 ... the Western Cape. HIV infection in this age group is associated with recent infection, thus .... lowest HIV prevalence in South Africa) using two different sources of data at two different time points in different age groups in order ...

  20. Building partnerships to address the HIV epidemic.

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    Chua, A C; Leo, Y S; Lee, C C

    2008-05-01

    Batam is one of the islands comprising the Riau Province in Indonesia, and is closest to Singapore. It is a popular destination of many Singaporeans. Surveillance reports among commercial sex workers conducted in Batam showed the prevalence rate of human immunodeficiency virus (HIV) is 16.2 percent. At the end of 2006, the total number of HIV-infected Singaporeans was 3,060, the majority being infected via heterosexual transmission. The aim of the Indonesian government is to rapidly scale up HIV treatment to those needing it. One of the factors critical to the rapid scale-up is healthcare worker training. An intersectoral collaboration addressing the issue of HIV care and treatment with a hospital in Batam was created. The first activity of the collaboration was a two-day HIV training course conducted in February 2007. The aim of the course was to provide a basic understanding of HIV, as well as knowledge on common opportunistic infections that may present to a general hospital or clinical setting. 34 doctors from 23 institutions in Batam and three doctors from two hospitals in the Riau Islands attended the two-day HIV training course. The participants found the training very useful and highly relevant. This first HIV training provided a foundation to build on further HIV education. It is our belief that through the HIV training programme, there will be more awareness of HIV among the various medical institutions in Batam. As the HIV epidemic knows no borders, working with neighbouring countries is one strategy that deserves attention.

  1. The origin and emergence of an HIV-1 epidemic:

    DEFF Research Database (Denmark)

    Bruhn, Christian Anders Wathne; Audelin, Anne M.; Helleberg, Marie

    2014-01-01

    To describe, at patient-level detail, the determining events and factors involved in the development of a country's HIV-1 epidemic.......To describe, at patient-level detail, the determining events and factors involved in the development of a country's HIV-1 epidemic....

  2. Abia State HIV epidemic and response: challenges and prospects.

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    Onyeonoro, Ugochukwu Uchenna; Emelumadu, Obiageli Fidelia; Nwamoh, Uche Ngozi; Ukegbu, Andrew Ugwunna; Okafor, Godwin Oc

    2014-11-13

    Since the first seroprevalence survey in 1999, the HIV prevalence in Abia State has increased from 1.8% to 7.3% in 2010. The state is currently experiencing a generalized epidemic, with most transmission occurring through heterosexual low-risk sex. Drivers of the epidemic include low knowledge of HIV prevention, low risk perception, predominantly male factor-driven risky sexual behavior, and low condom use. This study reviewed the state HIV epidemic trend in relation to response, sought to identify the gaps between the epidemic and response, and recommended measures to strengthen the state response.

  3. Untangling the Interplay between Epidemic Spread and Transmission Network Dynamics.

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    Christel Kamp

    Full Text Available The epidemic spread of infectious diseases is ubiquitous and often has a considerable impact on public health and economic wealth. The large variability in the spatio-temporal patterns of epidemics prohibits simple interventions and requires a detailed analysis of each epidemic with respect to its infectious agent and the corresponding routes of transmission. To facilitate this analysis, we introduce a mathematical framework which links epidemic patterns to the topology and dynamics of the underlying transmission network. The evolution, both in disease prevalence and transmission network topology, is derived from a closed set of partial differential equations for infections without allowing for recovery. The predictions are in excellent agreement with complementarily conducted agent-based simulations. The capacity of this new method is demonstrated in several case studies on HIV epidemics in synthetic populations: it allows us to monitor the evolution of contact behavior among healthy and infected individuals and the contributions of different disease stages to the spreading of the epidemic. This gives both direction to and a test bed for targeted intervention strategies for epidemic control. In conclusion, this mathematical framework provides a capable toolbox for the analysis of epidemics from first principles. This allows for fast, in silico modeling--and manipulation--of epidemics and is especially powerful if complemented with adequate empirical data for parameterization.

  4. Know your epidemic, know your response: targeting HIV in Asia

    DEFF Research Database (Denmark)

    Lazarus, Jeff; Curth, Nadja; Bridge, Jamie

    2010-01-01

    This article provides an overview of the HIV epidemic in Asia, the context within which the epidemic is evolving, and the key actions to address the challenges faced by countries and risk groups. HIV epidemics across Asia are predominantly concentrated among most-at-risk populations. Although...... prevention and treatment services. In order to reach the Millennium Development Goal of halting and reversing the spread of HIV by 2015 and to achieve universal access to HIV treatment, these barriers must be overcome across Asia. High-impact programs must be targeted at those in need, with continuous...

  5. HIV epidemiology. The early spread and epidemic ignition of HIV-1 in human populations.

    Science.gov (United States)

    Faria, Nuno R; Rambaut, Andrew; Suchard, Marc A; Baele, Guy; Bedford, Trevor; Ward, Melissa J; Tatem, Andrew J; Sousa, João D; Arinaminpathy, Nimalan; Pépin, Jacques; Posada, David; Peeters, Martine; Pybus, Oliver G; Lemey, Philippe

    2014-10-03

    Thirty years after the discovery of HIV-1, the early transmission, dissemination, and establishment of the virus in human populations remain unclear. Using statistical approaches applied to HIV-1 sequence data from central Africa, we show that from the 1920s Kinshasa (in what is now the Democratic Republic of Congo) was the focus of early transmission and the source of pre-1960 pandemic viruses elsewhere. Location and dating estimates were validated using the earliest HIV-1 archival sample, also from Kinshasa. The epidemic histories of HIV-1 group M and nonpandemic group O were similar until ~1960, after which group M underwent an epidemiological transition and outpaced regional population growth. Our results reconstruct the early dynamics of HIV-1 and emphasize the role of social changes and transport networks in the establishment of this virus in human populations. Copyright © 2014, American Association for the Advancement of Science.

  6. INTRODUCTION The global HIV epidemic continues to expand with ...

    African Journals Online (AJOL)

    maybe potentially dangerous in low resource settings.6. Women infected with ... The HIV epidemic in children parallels that among women on account of perinatal ... unknown.14, 15 Immune suppression resulting from general anaesthetics ...

  7. The global spread of HIV-1 subtype B epidemic

    NARCIS (Netherlands)

    Magiorkinis, Gkikas; Angelis, Konstantinos; Mamais, Ioannis; Katzourakis, Aris; Hatzakis, Angelos; Albert, Jan; Lawyer, Glenn; Hamouda, Osamah; Struck, Daniel; Vercauteren, Jurgen; Wensing, Annemarie; Alexiev, Ivailo; Åsjö, Birgitta; Balotta, Claudia; Gomes, Perpétua; Camacho, Ricardo J.; Coughlan, Suzie; Griskevicius, Algirdas; Grossman, Zehava; Horban, Anders; Kostrikis, Leondios G.; Lepej, Snjezana J.; Liitsola, Kirsi; Linka, Marek; Nielsen, Claus; Otelea, Dan; Paredes, Roger; Poljak, Mario; Puchhammer-Stöckl, Elizabeth; Schmit, Jean Claude; Sönnerborg, Anders; Staneková, Danica; Stanojevic, Maja; Stylianou, Dora C.; Boucher, Charles A B; Nikolopoulos, Georgios; Vasylyeva, Tetyana; Friedman, Samuel R.; van de Vijver, David; Angarano, Gioacchino; Chaix, Marie Laure; de Luca, Andrea; Korn, Klaus; Loveday, Clive; Soriano, Vincent; Yerly, Sabine; Zazzi, Mauricio; Vandamme, Anne Mieke; Paraskevis, Dimitrios

    2016-01-01

    Human immunodeficiency virus type 1 (HIV-1) was discovered in the early 1980s when the virus had already established a pandemic. For at least three decades the epidemic in the Western World has been dominated by subtype B infections, as part of a sub-epidemic that traveled from Africa through Haiti

  8. The global spread of HIV-1 subtype B epidemic

    NARCIS (Netherlands)

    G. Magiorkinis (Gkikas); K. Angelis (Konstantinos); I. Mamais (Ioannis); Katzourakis, A. (Aris); A. Hatzakis (Angelos); J. Albert (Jan); Lawyer, G. (Glenn); O. Hamouda (Osamah); D. Struck (Daniel); J. Vercauteren (Jurgen); A. Wensing (Amj); I. Alexiev (Ivailo); B. Åsjö (Birgitta); C. Balotta (Claudia); Gomes, P. (Perpétua); R.J. Camacho (Ricardo Jorge); S. Coughlan (Suzie); A. Griskevicius (Algirdas); Z. Grossman (Zehava); Horban, A. (Anders); L.G. Kostrikis (Leondios); Lepej, S.J. (Snjezana J.); K. Liitsola (Kirsi); M. Linka (Marek); C. Nielsen; D. Otelea (Dan); R. Paredes (Roger); M. Poljak (Mario); E. Puchhammer-Stöckl (Elisabeth); J.C. Schmit; A. Sonnerborg (Anders); D. Stanekova (Danica); M. Stanojevic (Maja); Stylianou, D.C. (Dora C.); C.A.B. Boucher (Charles); Nikolopoulos, G. (Georgios); Vasylyeva, T. (Tetyana); Friedman, S.R. (Samuel R.); D.A.M.C. van de Vijver (David); G. Angarano (Guiseppe); M.L. Chaix (Marie Laure); A. de Luca (Andrea); K. Korn (Klaus); Loveday, C. (Clive); V. Soriano (Virtudes); S. Yerly (Sabine); M. Zazzi; A.M. Vandamme (Anne Mieke); D. Paraskevis (Dimitrios)

    2016-01-01

    textabstractHuman immunodeficiency virus type 1 (HIV-1) was discovered in the early 1980s when the virus had already established a pandemic. For at least three decades the epidemic in the Western World has been dominated by subtype B infections, as part of a sub-epidemic that traveled from Africa

  9. HIV-1 epidemic in Warao Amerindians from Venezuela: spatial phylodynamics and epidemiological patterns.

    Science.gov (United States)

    Villalba, Julian A; Bello, Gonzalo; Maes, Mailis; Sulbaran, Yoneira F; Garzaro, Domingo; Loureiro, Carmen L; Rangel, Hector R; de Waard, Jacobus H; Pujol, Flor H

    2013-07-17

    We previously reported HIV-1 infection in Warao Amerindians from Venezuela. The aim of this study was to evaluate the extent and the dynamic of HIV-1 dissemination in eight Warao communities. HIV-1 infection was evaluated in 576 Warao Amerindians from the Orinoco Delta. Partial HIV-1 pol sequences were analyzed to reconstruct the spatiotemporal and demographic dynamics of the epidemic. HIV-1 antibodies were present in 9.55% of Warao Amerindians, ranging from 0 to 22%. A significantly higher prevalence was found in men (15.6%) compared with women (2.6%), reaching up to 35% in men from one community. All but one isolates were classified as subtype B. Warao's HIV-1 subtype-B epidemic resulted from a single viral introduction at around the early 2000s. After an initial phase of slow growth, the subtype B started to spread at a fast rate (0.8/year) following two major routes of migration within the communities. A dramatic high prevalence was documented in almost all the communities of Warao Amerindians from the Orinoco Delta tested for HIV-1 infection. This epidemic resulted from the dissemination of a single HIV-1 subtype B founder strain introduced about 10 years ago and its size is probably doubling every year, creating a situation that can be devastating for this vulnerable Amerindian group.

  10. A qualitative view of the HIV epidemic in coastal Ecuador.

    Science.gov (United States)

    Beckman, Adam L; Wilson, Magdalena M; Prabhu, Vishaal; Soekoe, Nicola; Mata, Humberto; Grau, Lauretta E

    2016-01-01

    In 2013 approximately 37,000 people were living with HIV in Ecuador (prevalence 0.4%), representing a generalized epidemic where most new infections arise from sexual interactions in the general population. Studies that examine attitudes towards people living with HIV (PLWH), individual risk perception of acquiring HIV amongst Ecuadorians, and the ways in which levels of risk perception may affect risk behaviors are lacking. This qualitative study aimed to fill this gap in the literature by investigating these issues in the rural, coastal community of Manglaralto, Ecuador, which has among the highest incidence of HIV in Ecuador. We conducted interviews with 15 patients at Manglaralto Hospital. Analysis of interview transcripts revealed widespread negative attitudes towards PLWH, prevalent risk behaviors such as multiple sex partners and lack of condom use, and low individual risk-perception of contracting HIV. These findings underscore the need for increased efforts to prevent further growth of the HIV epidemic in Ecuador.

  11. A qualitative view of the HIV epidemic in coastal Ecuador

    Directory of Open Access Journals (Sweden)

    Adam L. Beckman

    2016-11-01

    Full Text Available In 2013 approximately 37,000 people were living with HIV in Ecuador (prevalence 0.4%, representing a generalized epidemic where most new infections arise from sexual interactions in the general population. Studies that examine attitudes towards people living with HIV (PLWH, individual risk perception of acquiring HIV amongst Ecuadorians, and the ways in which levels of risk perception may affect risk behaviors are lacking. This qualitative study aimed to fill this gap in the literature by investigating these issues in the rural, coastal community of Manglaralto, Ecuador, which has among the highest incidence of HIV in Ecuador. We conducted interviews with 15 patients at Manglaralto Hospital. Analysis of interview transcripts revealed widespread negative attitudes towards PLWH, prevalent risk behaviors such as multiple sex partners and lack of condom use, and low individual risk-perception of contracting HIV. These findings underscore the need for increased efforts to prevent further growth of the HIV epidemic in Ecuador.

  12. The HIV/AIDS epidemic in Cuba: description and tentative explanation of its low HIV prevalence

    Directory of Open Access Journals (Sweden)

    Clémençon Stéphan

    2007-11-01

    Full Text Available Abstract Background The Cuban HIV/AIDS epidemic has the lowest prevalence rate of the Caribbean region. The objective of this paper is to give an overview of the HIV/AIDS epidemic in Cuba and to explore the reasons for this low prevalence. Methods Data were obtained from the Cuban HIV/AIDS programme established in 1983. This programme has an extensive adult HIV testing policy, including testing of all pregnant women. HIV and AIDS cases have been recorded since 1986. Persons found to be HIV-positive are interviewed on their sexual behaviour and partners. Tracing and voluntary testing of these partners are organised. Epidemiological description of this epidemic was obtained from analysis of this data set. Using elementary mathematical analyses, we estimated the coverage of the detection system (percentage of HIV-positive adults detected and the average period between HIV infection and detection. Estimated HIV prevalence rates were corrected to account for the coverage. Results HIV prevalence has increased since 1996. In 2005, the prevalence among pregnant women was 1.2 per 10,000 (16/137000. Estimated HIV prevalence among 15- to 49-year-olds was 8.1 per 10,000 (4913/6065000; 95%CI: 7.9 per 10,000 – 8.3 per 10,000. Most (77% of the HIV-positive adults were men, most (85.1% of the detected HIV-positive men were reported as having sex with men (MSM, and most of the HIV-positive women reported having had sex with MSM. The average period between HIV infection and detection was estimated to be 2.1 years (IQR = 1.7 – 2.2 years. We estimated that, for the year 2005, 79.6% (IQR: 77.3 – 81.4% of the HIV-positive persons were detected. Conclusion MSM drive the HIV epidemic in Cuba. The extensive HIV testing policy may be an important factor in explaining the low HIV prevalence. To reduce the HIV epidemic in Cuba, the epidemic among MSM should be addressed. To understand this epidemic further, data on sexual behaviour should be collected. Now that

  13. Cultural Practices and the HIV Epidemic in Swaziland: Student\\'s ...

    African Journals Online (AJOL)

    International Journal of Educational Research ... Cultural Practices and the HIV Epidemic in Swaziland: Student\\'s Perspectives and Challenges for School Counsellors ... Keywords: Cultural Practices, HIV Epidemic; Behaviour Change.

  14. HIV epidemic appraisals for assisting in the design of effective prevention programmes: shifting the paradigm back to basics.

    Directory of Open Access Journals (Sweden)

    Sharmistha Mishra

    Full Text Available To design HIV prevention programmes, it is critical to understand the temporal and geographic aspects of the local epidemic and to address the key behaviours that drive HIV transmission. Two methods have been developed to appraise HIV epidemics and guide prevention strategies. The numerical proxy method classifies epidemics based on current HIV prevalence thresholds. The Modes of Transmission (MOT model estimates the distribution of incidence over one year among risk-groups. Both methods focus on the current state of an epidemic and provide short-term metrics which may not capture the epidemiologic drivers. Through a detailed analysis of country and sub-national data, we explore the limitations of the two traditional methods and propose an alternative approach.We compared outputs of the traditional methods in five countries for which results were published, and applied the numeric and MOT model to India and six districts within India. We discovered three limitations of the current methods for epidemic appraisal: (1 their results failed to identify the key behaviours that drive the epidemic; (2 they were difficult to apply to local epidemics with heterogeneity across district-level administrative units; and (3 the MOT model was highly sensitive to input parameters, many of which required extraction from non-regional sources. We developed an alternative decision-tree framework for HIV epidemic appraisals, based on a qualitative understanding of epidemiologic drivers, and demonstrated its applicability in India. The alternative framework offered a logical algorithm to characterize epidemics; it required minimal but key data.Traditional appraisals that utilize the distribution of prevalent and incident HIV infections in the short-term could misguide prevention priorities and potentially impede efforts to halt the trajectory of the HIV epidemic. An approach that characterizes local transmission dynamics provides a potentially more effective tool with

  15. Understanding the epidemic of HIV in South Africa

    African Journals Online (AJOL)

    the worst HIV epidemics in Africa. The lack of ... The data collected by the Department of Health through their annual ... Epidemiology Research Unit, PO Box 30606, Braamfontein, 2017. Brian Williams. ... socio-economic conditions. In the Western Cape, ... differs significantly from the mean value, which is 12.0 months (11.3 ...

  16. Stochastic dynamics of dengue epidemics.

    Science.gov (United States)

    de Souza, David R; Tomé, Tânia; Pinho, Suani T R; Barreto, Florisneide R; de Oliveira, Mário J

    2013-01-01

    We use a stochastic Markovian dynamics approach to describe the spreading of vector-transmitted diseases, such as dengue, and the threshold of the disease. The coexistence space is composed of two structures representing the human and mosquito populations. The human population follows a susceptible-infected-recovered (SIR) type dynamics and the mosquito population follows a susceptible-infected-susceptible (SIS) type dynamics. The human infection is caused by infected mosquitoes and vice versa, so that the SIS and SIR dynamics are interconnected. We develop a truncation scheme to solve the evolution equations from which we get the threshold of the disease and the reproductive ratio. The threshold of the disease is also obtained by performing numerical simulations. We found that for certain values of the infection rates the spreading of the disease is impossible, for any death rate of infected mosquitoes.

  17. The global spread of HIV-1 subtype B epidemic.

    Science.gov (United States)

    Magiorkinis, Gkikas; Angelis, Konstantinos; Mamais, Ioannis; Katzourakis, Aris; Hatzakis, Angelos; Albert, Jan; Lawyer, Glenn; Hamouda, Osamah; Struck, Daniel; Vercauteren, Jurgen; Wensing, Annemarie; Alexiev, Ivailo; Åsjö, Birgitta; Balotta, Claudia; Gomes, Perpétua; Camacho, Ricardo J; Coughlan, Suzie; Griskevicius, Algirdas; Grossman, Zehava; Horban, Anders; Kostrikis, Leondios G; Lepej, Snjezana J; Liitsola, Kirsi; Linka, Marek; Nielsen, Claus; Otelea, Dan; Paredes, Roger; Poljak, Mario; Puchhammer-Stöckl, Elizabeth; Schmit, Jean Claude; Sönnerborg, Anders; Staneková, Danica; Stanojevic, Maja; Stylianou, Dora C; Boucher, Charles A B; Nikolopoulos, Georgios; Vasylyeva, Tetyana; Friedman, Samuel R; van de Vijver, David; Angarano, Gioacchino; Chaix, Marie-Laure; de Luca, Andrea; Korn, Klaus; Loveday, Clive; Soriano, Vincent; Yerly, Sabine; Zazzi, Mauricio; Vandamme, Anne-Mieke; Paraskevis, Dimitrios

    2016-12-01

    Human immunodeficiency virus type 1 (HIV-1) was discovered in the early 1980s when the virus had already established a pandemic. For at least three decades the epidemic in the Western World has been dominated by subtype B infections, as part of a sub-epidemic that traveled from Africa through Haiti to United States. However, the pattern of the subsequent spread still remains poorly understood. Here we analyze a large dataset of globally representative HIV-1 subtype B strains to map their spread around the world over the last 50years and describe significant spread patterns. We show that subtype B travelled from North America to Western Europe in different occasions, while Central/Eastern Europe remained isolated for the most part of the early epidemic. Looking with more detail in European countries we see that the United Kingdom, France and Switzerland exchanged viral isolates with non-European countries than with European ones. The observed pattern is likely to mirror geopolitical landmarks in the post-World War II era, namely the rise and the fall of the Iron Curtain and the European colonialism. In conclusion, HIV-1 spread through specific migration routes which are consistent with geopolitical factors that affected human activities during the last 50years, such as migration, tourism and trade. Our findings support the argument that epidemic control policies should be global and incorporate political and socioeconomic factors. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  18. The History of the HIV/AIDS Epidemic in Africa.

    Science.gov (United States)

    Kagaayi, Joseph; Serwadda, David

    2016-08-01

    HIV testing of African immigrants in Belgium showed that HIV existed among Africans by 1983. However, the epidemic was recognized much later in most parts of sub-Saharan Africa (SSA) due to stigma and perceived fear of possible negative consequences to the countries' economies. This delay had devastating mortality, morbidity, and social consequences. In countries where earlier recognition occurred, political leadership was vital in mounting a response. The response involved establishment of AIDS control programs and research on the HIV epidemiology and candidate preventive interventions. Over time, the number of effective interventions has grown; the game changer being triple antiretroviral therapy (ART). ART has led to a rapid decline in HIV-related morbidity and mortality in addition to prevention of onward HIV transmission. Other effective interventions include safe male circumcision, pre-exposure prophylaxis, and post-exposure prophylaxis. However, since none of these is sufficient by itself, delivering a combination package of these interventions is important for ending the HIV epidemic as a public health threat.

  19. Phylodynamics of the HIV-1 epidemic in Cuba.

    Science.gov (United States)

    Delatorre, Edson; Bello, Gonzalo

    2013-01-01

    Previous studies have shown that the HIV-1 epidemic in Cuba displayed a complex molecular epidemiologic profile with circulation of several subtypes and circulating recombinant forms (CRF); but the evolutionary and population history of those viral variants remains unknown. HIV-1 pol sequences of the most prevalent Cuban lineages (subtypes B, C and G, CRF18_cpx, CRF19_cpx, and CRFs20/23/24_BG) isolated between 1999 and 2011 were analyzed. Maximum-likelihood analyses revealed multiple introductions of subtype B (n≥66), subtype C (n≥10), subtype G (n≥8) and CRF18_cpx (n≥2) viruses in Cuba. The bulk of HIV-1 infections in this country, however, was caused by dissemination of a few founder strains probably introduced from North America/Europe (clades B(CU-I) and B(CU-II)), east Africa (clade C(CU-I)) and central Africa (clades G(CU), CRF18(CU) and CRF19(CU)), or locally generated (clades CRFs20/23/24_BG). Bayesian-coalescent analyses show that the major HIV-1 founder strains were introduced into Cuba during 1985-1995; whereas the CRFs_BG strains emerged in the second half of the 1990s. Most HIV-1 Cuban clades appear to have experienced an initial period of fast exponential spread during the 1990s and early 2000s, followed by a more recent decline in growth rate. The median initial growth rate of HIV-1 Cuban clades ranged from 0.4 year⁻¹ to 1.6 year⁻¹. Thus, the HIV-1 epidemic in Cuba has been a result of the successful introduction of a few viral strains that began to circulate at a rather late time of the AIDS pandemic, but then were rapidly disseminated through local transmission networks.

  20. Dynamics of epidemics outbreaks in heterogeneous populations

    Science.gov (United States)

    Brockmann, Dirk; Morales-Gallardo, Alejandro; Geisel, Theo

    2007-03-01

    The dynamics of epidemic outbreaks have been investigated in recent years within two alternative theoretical paradigms. The key parameter of mean field type of models such as the SIR model is the basic reproduction number R0, the average number of secondary infections caused by one infected individual. Recently, scale free network models have received much attention as they account for the high variability in the number of social contacts involved. These models predict an infinite basic reproduction number in some cases. We investigate the impact of heterogeneities of contact rates in a generic model for epidemic outbreaks. We present a system in which both the time periods of being infectious and the time periods between transmissions are Poissonian processes. The heterogeneities are introduced by means of strongly variable contact rates. In contrast to scale free network models we observe a finite basic reproduction number and, counterintuitively a smaller overall epidemic outbreak as compared to the homogeneous system. Our study thus reveals that heterogeneities in contact rates do not necessarily facilitate the spread to infectious disease but may well attenuate it.

  1. Data and methods to characterize the role of sex work and to inform sex work programs in generalized HIV epidemics: evidence to challenge assumptions.

    Science.gov (United States)

    Mishra, Sharmistha; Boily, Marie-Claude; Schwartz, Sheree; Beyrer, Chris; Blanchard, James F; Moses, Stephen; Castor, Delivette; Phaswana-Mafuya, Nancy; Vickerman, Peter; Drame, Fatou; Alary, Michel; Baral, Stefan D

    2016-08-01

    In the context of generalized human immunodeficiency virus (HIV) epidemics, there has been limited recent investment in HIV surveillance and prevention programming for key populations including female sex workers. Often implicit in the decision to limit investment in these epidemic settings are assumptions including that commercial sex is not significant to the sustained transmission of HIV, and HIV interventions designed to reach "all segments of society" will reach female sex workers and clients. Emerging empiric and model-based evidence is challenging these assumptions. This article highlights the frameworks and estimates used to characterize the role of sex work in HIV epidemics as well as the relevant empiric data landscape on sex work in generalized HIV epidemics and their strengths and limitations. Traditional approaches to estimate the contribution of sex work to HIV epidemics do not capture the potential for upstream and downstream sexual and vertical HIV transmission. Emerging approaches such as the transmission population attributable fraction from dynamic mathematical models can address this gap. To move forward, the HIV scientific community must begin by replacing assumptions about the epidemiology of generalized HIV epidemics with data and more appropriate methods of estimating the contribution of unprotected sex in the context of sex work. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Molecular phylodynamics of the heterosexual HIV epidemic in the United Kingdom.

    Directory of Open Access Journals (Sweden)

    Gareth J Hughes

    2009-09-01

    Full Text Available The heterosexual risk group has become the largest HIV infected group in the United Kingdom during the last 10 years, but little is known of the network structure and dynamics of viral transmission in this group. The overwhelming majority of UK heterosexual infections are of non-B HIV subtypes, indicating viruses originating among immigrants from sub-Saharan Africa. The high rate of HIV evolution, combined with the availability of a very high density sample of viral sequences from routine clinical care has allowed the phylodynamics of the epidemic to be investigated for the first time. Sequences of the viral protease and partial reverse transcriptase coding regions from 11,071 patients infected with HIV of non-B subtypes were studied. Of these, 2774 were closely linked to at least one other sequence by nucleotide distance. Including the closest sequences from the global HIV database identified 296 individuals that were in UK-based groups of 3 or more individuals. There were a total of 8 UK-based clusters of 10 or more, comprising 143/2774 (5% individuals, much lower than the figure of 25% obtained earlier for men who have sex with men (MSM. Sample dates were incorporated into relaxed clock phylogenetic analyses to estimate the dates of internal nodes. From the resulting time-resolved phylogenies, the internode lengths, used as estimates of maximum transmission intervals, had a median of 27 months overall, over twice as long as obtained for MSM (14 months, with only 2% of transmissions occurring in the first 6 months after infection. This phylodynamic analysis of non-B subtype HIV sequences representing over 40% of the estimated UK HIV-infected heterosexual population has revealed heterosexual HIV transmission in the UK is clustered, but on average in smaller groups and is transmitted with slower dynamics than among MSM. More effective intervention to restrict the epidemic may therefore be feasible, given effective diagnosis programmes.

  3. A hidden HIV epidemic among women in Vietnam

    Directory of Open Access Journals (Sweden)

    Tran Hien

    2008-01-01

    Full Text Available Abstract Background The HIV epidemic in Vietnam is still concentrated among high risk populations, including IDU and FSW. The response of the government has focused on the recognized high risk populations, mainly young male drug users. This concentration on one high risk population may leave other populations under-protected or unprepared for the risk and the consequences of HIV infection. In particular, attention to women's risks of exposure and needs for care may not receive sufficient attention as long as the perception persists that the epidemic is predominantly among young males. Without more knowledge of the epidemic among women, policy makers and planners cannot ensure that programs will also serve women's needs. Methods More than 300 documents appearing in the period 1990 to 2005 were gathered and reviewed to build an understanding of HIV infection and related risk behaviors among women and of the changes over time that may suggest needed policy changes. Results It appears that the risk of HIV transmission among women in Vietnam has been underestimated; the reported data may represent as little as 16% of the real number. Although modeling predicted that there would be 98,500 cases of HIV-infected women in 2005, only 15,633 were accounted for in reports from the health system. That could mean that in 2005, up to 83,000 women infected with HIV have not been detected by the health care system, for a number of possible reasons. For both detection and prevention, these women can be divided into sub-groups with different risk characteristics. They can be infected by sharing needles and syringes with IDU partners, or by having unsafe sex with clients, husbands or lovers. However, most new infections among women can be traced to sexual relations with young male injecting drug users engaged in extramarital sex. Each of these groups may need different interventions to increase the detection rate and thus ensure that the women receive the care they

  4. Epidemic Dynamics in Open Quantum Spin Systems

    Science.gov (United States)

    Pérez-Espigares, Carlos; Marcuzzi, Matteo; Gutiérrez, Ricardo; Lesanovsky, Igor

    2017-10-01

    We explore the nonequilibrium evolution and stationary states of an open many-body system that displays epidemic spreading dynamics in a classical and a quantum regime. Our study is motivated by recent experiments conducted in strongly interacting gases of highly excited Rydberg atoms where the facilitated excitation of Rydberg states competes with radiative decay. These systems approximately implement open quantum versions of models for population dynamics or disease spreading where species can be in a healthy, infected or immune state. We show that in a two-dimensional lattice, depending on the dominance of either classical or quantum effects, the system may display a different kind of nonequilibrium phase transition. We moreover discuss the observability of our findings in laser driven Rydberg gases with particular focus on the role of long-range interactions.

  5. Mandating the offer of HIV testing in New York: simulating the epidemic impact and resource needs.

    Science.gov (United States)

    Martin, Erika G; MacDonald, Roderick H; Smith, Lou C; Gordon, Daniel E; Tesoriero, James M; Laufer, Franklin N; Leung, Shu-Yin J; Rowe, Kirsten A; OʼConnell, Daniel A

    2015-01-01

    A 2010 New York law requires that patients aged 13-64 years be offered HIV testing in routine medical care settings. Past studies report the clinical outcomes, cost-effectiveness, and budget impact of expanded HIV testing nationally and within clinics but have not examined how state policies affect resource needs and epidemic outcomes. A system dynamics model of HIV testing and care was developed, where disease progression and transmission differ by awareness of HIV status, engagement in care, and disease stage. Data sources include HIV surveillance, Medicaid claims, and literature. The model projected how alternate implementation scenarios would change new infections, diagnoses, linkage to care, and living HIV cases over 10 years. Without the law, the model projects declining new infections, newly diagnosed cases, individuals newly linked to care, and fraction of undiagnosed cases (reductions of 62.8%, 59.7%, 54.1%, and 57.8%) and a slight increase in living diagnosed cases and individuals in care (2.2% and 6.1%). The law will further reduce new infections, diagnosed AIDS cases, and the fraction undiagnosed and initially increase and then decrease newly diagnosed cases. Outcomes were consistent across scenarios with different testing offer frequencies and implementation times but differed according to the level of implementation. A mandatory offer of HIV testing may increase diagnoses and avert infections but will not eliminate the epidemic. Despite declines in new infections, previously diagnosed cases will continue to need access to antiretroviral therapy, highlighting the importance of continued funding for HIV care.

  6. Early stages of the HIV epidemic among injecting drug users: Lessons to be learned

    Directory of Open Access Journals (Sweden)

    Tanvir Ahmed

    2014-09-01

    Full Text Available Injecting drug use driving the HIV epidemic is currently a major global public health concern. However, the early epidemic among injecting drug users (IDUs, more than three decades ago, was only concentrated in few places. The HIV epidemic among the IDUs in New York, USA; Edinburgh, Scotland, UK; and northern Italy provides examples of where the recorded prevalence exceeded 50% within a very short period of time. This brief review highlights historical perspectives of HIV transmission risk among IDUs during the early stages of the epidemic. Salient features and related experiences during this period might provide valuable insights for current HIV prevention. Our overview of the selected locations reemphasizes the importance of early prevention. The discussion also introduces to new researchers the early situation associated with the HIV epidemic in IDUs and highlights some crucial components need to be included during current HIV prevention activities.

  7. Epidemic dynamics and endemic states in complex networks

    Science.gov (United States)

    Pastor-Satorras, Romualdo; Vespignani, Alessandro

    2001-06-01

    We study by analytical methods and large scale simulations a dynamical model for the spreading of epidemics in complex networks. In networks with exponentially bounded connectivity we recover the usual epidemic behavior with a threshold defining a critical point below that the infection prevalence is null. On the contrary, on a wide range of scale-free networks we observe the absence of an epidemic threshold and its associated critical behavior. This implies that scale-free networks are prone to the spreading and the persistence of infections whatever spreading rate the epidemic agents might possess. These results can help understanding computer virus epidemics and other spreading phenomena on communication and social networks.

  8. Epidemic dynamics and endemic states in complex networks

    International Nuclear Information System (INIS)

    Pastor-Satorras, Romualdo; Vespignani, Alessandro

    2001-01-01

    We study by analytical methods and large scale simulations a dynamical model for the spreading of epidemics in complex networks. In networks with exponentially bounded connectivity we recover the usual epidemic behavior with a threshold defining a critical point below that the infection prevalence is null. On the contrary, on a wide range of scale-free networks we observe the absence of an epidemic threshold and its associated critical behavior. This implies that scale-free networks are prone to the spreading and the persistence of infections whatever spreading rate the epidemic agents might possess. These results can help understanding computer virus epidemics and other spreading phenomena on communication and social networks

  9. The HIV epidemic in Greenland - a slow spreading infection among adult heterosexual Greenlanders

    DEFF Research Database (Denmark)

    Bjørn-Mortensen, Karen; Ladefoged, Karin; Obel, Niels

    2013-01-01

    We aimed to characterise the HIV epidemic in Greenland and to determine incidence, prevalence, mortality rates (MR) and specific causes of deaths.......We aimed to characterise the HIV epidemic in Greenland and to determine incidence, prevalence, mortality rates (MR) and specific causes of deaths....

  10. Factors affecting the HIV/AIDS epidemic: An ecological analysis of ...

    African Journals Online (AJOL)

    Factors affecting the HIV/AIDS epidemic: An ecological analysis of global data. ... Backward multiple linear regression analysis identified the proportion of Muslims, physicians density, and adolescent fertility rate are as the three most prominent factors linked with the national HIV epidemic. Conclusions: The findings support ...

  11. Epidemic dynamics on a risk-based evolving social network

    Science.gov (United States)

    Antwi, Shadrack; Shaw, Leah

    2013-03-01

    Social network models have been used to study how behavior affects the dynamics of an infection in a population. Motivated by HIV, we consider how a trade-off between benefits and risks of sexual connections determine network structure and disease prevalence. We define a stochastic network model with formation and breaking of links as changes in sexual contacts. Each node has an intrinsic benefit its neighbors derive from connecting to it. Nodes' infection status is not apparent to others, but nodes with more connections (higher degree) are assumed more likely to be infected. The probability to form and break links is determined by a payoff computed from the benefit and degree-dependent risk. The disease is represented by a SI (susceptible-infected) model. We study network and epidemic evolution via Monte Carlo simulation and analytically predict the behavior with a heterogeneous mean field approach. The dependence of network connectivity and infection threshold on parameters is determined, and steady state degree distribution and epidemic levels are obtained. We also study a situation where system-wide infection levels alter perception of risk and cause nodes to adjust their behavior. This is a case of an adaptive network, where node status feeds back to change network geometry.

  12. [The HIV/AIDS epidemic and women in Mexico].

    Science.gov (United States)

    del Río-Zolezzi, A; Liguori, A L; Magis-Rodríguez, C; Valdespino-Gómez, J L; García-García, M de L; Sepúlveda-Amor, J

    1995-01-01

    This study presents an analysis of AIDS cases and seroprevalence of HIV infection among Mexican women, from the onset of the epidemic through June 1994, as well as the analysis of the social and cultural factors that put women in a powerless situation regarding the adoption of preventive measures. Since 1985, when the first AIDS cases among women were reported in Mexico and until June 1, 1994, a total of 2,767 cases have been reported, representing 14.8% of the total number of cases. The first cases of AIDS among women were associated to infected blood transfusions; however, in 1986, heterosexually transmitted cases began to appear. Currently, only 35% of newly reported AIDS cases are associated to blood transfusions while 64% of them are related to heterosexual transmission. In fact, two epidemics are evident: one transmitted through blood, showing a downward trend (duplication time 45 months), and a second one, heterosexually transmitted, increasing twice as fast (duplication time 27 months). The latter is expected to dominate AIDS epidemiology among women in the future. In general, women are more vulnerable to HIV/AIDS biologically, but also socially and culturally. Women's economic, social and cultural subordination to their sexual partners results in a situation that makes it difficult for them to assess their infection risk and even more, to negotiate taking preventive measures. This situation is even more disadvantageous to rural women and, together with the recent trend of the AIDS epidemic to ruralization and with internal and international migration (temporary work force migration to the USA), can result in deep demographic and social effects. We conclude that it is necessary to work on the design and assessment of preventive measures under women's control, that empower them to protect themselves even without their partner's awareness. Also, it is necessary to promote sexual education among young heterosexual couples on how to talk about sexual issues and

  13. Impact of HIV/aids epidemic on human capital development in West Africa.

    Science.gov (United States)

    Dauda, Rasaki Stephen

    2018-01-12

    West Africa occupies the third position with respect to the burden of human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) globally, after Southern and East Africa. About 5 million adults and children are infected with the disease in the subregion, while HIV prevalence in the general population hovers around 2% and 5%. This paper attempts to investigate the impact of HIV/AIDS epidemic on human capital development in 11 West African countries over the period 1990 to 2011. The study used a dynamic panel data modeling approach, using first difference, difference generalized methods of moment, and system generalized methods of moment estimating techniques. Four measures of HIV/AIDS and 2 human capital measures were used in the study. The findings revealed that HIV/AIDS pandemic had negative and significant impact on human capital in West Africa. However, the statistical significance was more pronounced on life expectancy (a measure of human capital), while the negative impact on school enrolment (another human capital measure) was not significant. It is therefore recommended that the spread of HIV/AIDS disease in West Africa should be effectively controlled, while the number of infected persons undergoing antiretroviral therapy in the subregion should be increased to a near 100% coverage. Copyright © 2018 John Wiley & Sons, Ltd.

  14. Dynamics of the HIV epidemic in southern China: sexual and drug-using behaviours among female sex workers and male clients in Yunnan.

    Science.gov (United States)

    Xu, J J; Smith, M K; Chu, J; Ding, G W; Chang, D F; Sharp, G B; Qian, H Z; Lu, L; Bi, A M; Wang, N

    2012-09-01

    To examine the HIV/sexually transmitted infection (STI)-related risk behaviours among community-based female sex workers (FSWs) and their clients in Yunnan Province, China, we performed a cross-sectional study of 705 FSWs and 100 male clients. We found that HIV seroprevalence among FSWs was 13.0% and the most prevalent STI was herpes simplex virus type 2 (HSV-2) (71.1%), followed by Chlamydia trachomatis (18.1%) and syphilis (8.8%). The 20% of FSWs who reported injection drug use also reported needle-sharing behaviours in the last three months. Drug-using FSWs had substantially higher HIV and HSV-2 prevalence, serviced more clients and had a longer history of sex work than non-using FSWs. In total, 57.0% of male clients did not consistently use condoms with FSWs, 2.0% reported illicit drug use and 17.0% had STI symptoms in the last year. The dual risk behaviours of drug-using FSWs and clients place them at greater risk of HIV infection. Intervention programmes must adopt comprehensive methods.

  15. Epidemic dynamics and endemic states in complex networks

    OpenAIRE

    Pastor-Satorras, Romualdo; Vespignani, Alessandro

    2001-01-01

    We study by analytical methods and large scale simulations a dynamical model for the spreading of epidemics in complex networks. In networks with exponentially bounded connectivity we recover the usual epidemic behavior with a threshold defining a critical point below which the infection prevalence is null. On the contrary, on a wide range of scale-free networks we observe the absence of an epidemic threshold and its associated critical behavior. This implies that scale-free networks are pron...

  16. HIV status awareness, partnership dissolution and HIV transmission in generalized epidemics.

    Science.gov (United States)

    Reniers, Georges; Armbruster, Benjamin

    2012-01-01

    HIV status aware couples with at least one HIV positive partner are characterized by high separation and divorce rates. This phenomenon is often described as a corollary of couples HIV Testing and Counseling (HTC) that ought to be minimized. In this contribution, we demonstrate the implications of partnership dissolution in serodiscordant couples for the propagation of HIV. We develop a compartmental model to study epidemic outcomes of elevated partnership dissolution rates in serodiscordant couples and parameterize it with estimates from population-based data (Rakai, Uganda). Via its effect on partnership dissolution, every percentage point increase in HIV status awareness reduces HIV incidence in monogamous populations by 0.27 percent for women and 0.63 percent for men. These effects are even larger when the assumption of monogamy can be relaxed, but are moderated by other behavior changes (e.g., increased condom use) in HIV status aware serodiscordant partnerships. When these behavior changes are taken into account, each percentage point increase in HIV status awareness reduces HIV incidence by 0.13 and 0.32 percent for women and men, respectively (assuming monogamy). The partnership dissolution effect exists because it decreases the fraction of serodiscordant couples in the population and prolongs the time that individuals spend outside partnerships. Our model predicts that elevated partnership dissolution rates in HIV status aware serodiscordant couples reduce the spread of HIV. As a consequence, the full impact of couples HTC for HIV prevention is probably larger than recognized to date. Particularly high partnership dissolution rates in female positive serodiscordant couples contribute to the gender imbalance in HIV infections.

  17. HIV status awareness, partnership dissolution and HIV transmission in generalized epidemics.

    Directory of Open Access Journals (Sweden)

    Georges Reniers

    Full Text Available HIV status aware couples with at least one HIV positive partner are characterized by high separation and divorce rates. This phenomenon is often described as a corollary of couples HIV Testing and Counseling (HTC that ought to be minimized. In this contribution, we demonstrate the implications of partnership dissolution in serodiscordant couples for the propagation of HIV.We develop a compartmental model to study epidemic outcomes of elevated partnership dissolution rates in serodiscordant couples and parameterize it with estimates from population-based data (Rakai, Uganda.Via its effect on partnership dissolution, every percentage point increase in HIV status awareness reduces HIV incidence in monogamous populations by 0.27 percent for women and 0.63 percent for men. These effects are even larger when the assumption of monogamy can be relaxed, but are moderated by other behavior changes (e.g., increased condom use in HIV status aware serodiscordant partnerships. When these behavior changes are taken into account, each percentage point increase in HIV status awareness reduces HIV incidence by 0.13 and 0.32 percent for women and men, respectively (assuming monogamy. The partnership dissolution effect exists because it decreases the fraction of serodiscordant couples in the population and prolongs the time that individuals spend outside partnerships.Our model predicts that elevated partnership dissolution rates in HIV status aware serodiscordant couples reduce the spread of HIV. As a consequence, the full impact of couples HTC for HIV prevention is probably larger than recognized to date. Particularly high partnership dissolution rates in female positive serodiscordant couples contribute to the gender imbalance in HIV infections.

  18. Concurrency-Induced Transitions in Epidemic Dynamics on Temporal Networks.

    Science.gov (United States)

    Onaga, Tomokatsu; Gleeson, James P; Masuda, Naoki

    2017-09-08

    Social contact networks underlying epidemic processes in humans and animals are highly dynamic. The spreading of infections on such temporal networks can differ dramatically from spreading on static networks. We theoretically investigate the effects of concurrency, the number of neighbors that a node has at a given time point, on the epidemic threshold in the stochastic susceptible-infected-susceptible dynamics on temporal network models. We show that network dynamics can suppress epidemics (i.e., yield a higher epidemic threshold) when the node's concurrency is low, but can also enhance epidemics when the concurrency is high. We analytically determine different phases of this concurrency-induced transition, and confirm our results with numerical simulations.

  19. Concurrency-Induced Transitions in Epidemic Dynamics on Temporal Networks

    Science.gov (United States)

    Onaga, Tomokatsu; Gleeson, James P.; Masuda, Naoki

    2017-09-01

    Social contact networks underlying epidemic processes in humans and animals are highly dynamic. The spreading of infections on such temporal networks can differ dramatically from spreading on static networks. We theoretically investigate the effects of concurrency, the number of neighbors that a node has at a given time point, on the epidemic threshold in the stochastic susceptible-infected-susceptible dynamics on temporal network models. We show that network dynamics can suppress epidemics (i.e., yield a higher epidemic threshold) when the node's concurrency is low, but can also enhance epidemics when the concurrency is high. We analytically determine different phases of this concurrency-induced transition, and confirm our results with numerical simulations.

  20. Dynamical processes and epidemic threshold on nonlinear coupled multiplex networks

    Science.gov (United States)

    Gao, Chao; Tang, Shaoting; Li, Weihua; Yang, Yaqian; Zheng, Zhiming

    2018-04-01

    Recently, the interplay between epidemic spreading and awareness diffusion has aroused the interest of many researchers, who have studied models mainly based on linear coupling relations between information and epidemic layers. However, in real-world networks the relation between two layers may be closely correlated with the property of individual nodes and exhibits nonlinear dynamical features. Here we propose a nonlinear coupled information-epidemic model (I-E model) and present a comprehensive analysis in a more generalized scenario where the upload rate differs from node to node, deletion rate varies between susceptible and infected states, and infection rate changes between unaware and aware states. In particular, we develop a theoretical framework of the intra- and inter-layer dynamical processes with a microscopic Markov chain approach (MMCA), and derive an analytic epidemic threshold. Our results suggest that the change of upload and deletion rate has little effect on the diffusion dynamics in the epidemic layer.

  1. Dynamical Interplay between Awareness and Epidemic Spreading in Multiplex Networks

    Science.gov (United States)

    Granell, Clara; Gómez, Sergio; Arenas, Alex

    2013-09-01

    We present the analysis of the interrelation between two processes accounting for the spreading of an epidemic, and the information awareness to prevent its infection, on top of multiplex networks. This scenario is representative of an epidemic process spreading on a network of persistent real contacts, and a cyclic information awareness process diffusing in the network of virtual social contacts between the same individuals. The topology corresponds to a multiplex network where two diffusive processes are interacting affecting each other. The analysis using a microscopic Markov chain approach reveals the phase diagram of the incidence of the epidemics and allows us to capture the evolution of the epidemic threshold depending on the topological structure of the multiplex and the interrelation with the awareness process. Interestingly, the critical point for the onset of the epidemics has a critical value (metacritical point) defined by the awareness dynamics and the topology of the virtual network, from which the onset increases and the epidemics incidence decreases.

  2. Dynamical interplay between awareness and epidemic spreading in multiplex networks.

    Science.gov (United States)

    Granell, Clara; Gómez, Sergio; Arenas, Alex

    2013-09-20

    We present the analysis of the interrelation between two processes accounting for the spreading of an epidemic, and the information awareness to prevent its infection, on top of multiplex networks. This scenario is representative of an epidemic process spreading on a network of persistent real contacts, and a cyclic information awareness process diffusing in the network of virtual social contacts between the same individuals. The topology corresponds to a multiplex network where two diffusive processes are interacting affecting each other. The analysis using a microscopic Markov chain approach reveals the phase diagram of the incidence of the epidemics and allows us to capture the evolution of the epidemic threshold depending on the topological structure of the multiplex and the interrelation with the awareness process. Interestingly, the critical point for the onset of the epidemics has a critical value (metacritical point) defined by the awareness dynamics and the topology of the virtual network, from which the onset increases and the epidemics incidence decreases.

  3. Stability analysis of an HIV/AIDS epidemic model with treatment

    Science.gov (United States)

    Cai, Liming; Li, Xuezhi; Ghosh, Mini; Guo, Baozhu

    2009-07-01

    An HIV/AIDS epidemic model with treatment is investigated. The model allows for some infected individuals to move from the symptomatic phase to the asymptomatic phase by all sorts of treatment methods. We first establish the ODE treatment model with two infective stages. Mathematical analyses establish that the global dynamics of the spread of the HIV infectious disease are completely determined by the basic reproduction number [real]0. If [real]01. Then, we introduce a discrete time delay to the model to describe the time from the start of treatment in the symptomatic stage until treatment effects become visible. The effect of the time delay on the stability of the endemically infected equilibrium is investigated. Moreover, the delay model exhibits Hopf bifurcations by using the delay as a bifurcation parameter. Finally, numerical simulations are presented to illustrate the results.

  4. Epidemic impacts of a community empowerment intervention for HIV prevention among female sex workers in generalized and concentrated epidemics.

    Science.gov (United States)

    Wirtz, Andrea L; Pretorius, Carel; Beyrer, Chris; Baral, Stefan; Decker, Michele R; Sherman, Susan G; Sweat, Michael; Poteat, Tonia; Butler, Jennifer; Oelrichs, Robert; Semini, Iris; Kerrigan, Deanna

    2014-01-01

    Sex workers have endured a high burden of HIV infection in and across HIV epidemics. A comprehensive, community empowerment-based HIV prevention intervention emphasizes sex worker organization and mobilization to address HIV risk and often includes community-led peer education, condom distribution, and other activities. Meta-analysis of such interventions suggests a potential 51% reduction in inconsistent condom use. Mathematical modeling exercises provide theoretical insight into potential impacts of the intervention on HIV incidence and burden in settings where interventions have not yet been implemented. We used a deterministic model, Goals, to project the impact on HIV infections when the community empowerment interventions were scaled up among female sex workers in Kenya, Thailand, Brazil, and Ukraine. Modeling scenarios included expansion of the comprehensive community empowerment-based HIV prevention intervention from baseline coverage over a 5-year period (5-65% in Kenya and Ukraine; 10-70% in Thailand and Brazil), while other interventions were held at baseline levels. A second exercise increased the intervention coverage simultaneously with equitable access to ART for sex workers. Impacts on HIV outcomes among sex workers and adults are observed from 2012-2016 and, compared to status quo when all interventions are held constant. Optimistic but feasible coverage (65%-70%) of the intervention demonstrated a range of impacts on HIV: 220 infections averted over 5 yrs. among sex workers in Thailand, 1,830 in Brazil, 2,220 in Ukraine, and 10,800 infections in Kenya. Impacts of the intervention for female sex workers extend to the adult population, cumulatively averting 730 infections in Thailand to 20,700 adult infections in Kenya. Impacts vary by country, influenced by HIV prevalence in risk groups, risk behaviors, intervention use, and population size. A community empowerment approach to HIV prevention and access to universal ART for female sex workers is a

  5. The Characteristics of TB Epidemic and TB/HIV Co-Infection Epidemic: A 2007-2013 Retrospective Study in Urumqi, Xinjiang Province, China.

    Directory of Open Access Journals (Sweden)

    Wang Wei

    Full Text Available This study was aimed to find out epidemiologic characteristic of tuberculosis (TB cases, and Human Immunodeficiency Virus (HIV positive cases among TB patients (TB/HIV co-infection through demographic, temporal, and spatial study in Urumqi.Descriptive statistics and multivariate logistic regression were applied to identify the epidemiologic characteristics and risk factors of TB epidemic and TB/HIV co-infection epidemic. All addresses of each TB case, TB/HIV co-infection case, and administrative street were transformed into geographical coordinate. Subsequently, the geocoded address for 82 streets was transformed into a dot map used as the basis of spatial datasets. In addition, the paper also used quantile map and the spatial scan statistic in order to identify the spatial distribution and spatial clusters of TB epidemic and TB/HIV co-infection epidemic.There was a declining trend of the notification rates of TB epidemic from 2007 to 2009, as well as a rising trend from 2010 to 2013. However, the notification rates of TB/HIV co-infection epidemic showed a rising trend from 2007 to 2010, and a declining trend from 2011 to 2013. Moreover, a significant share of TB epidemic and TB/HIV co-infection epidemic happened between the age of 15 to 45 years old, indicating an increase in risk of TB and TB/HIV infection. It is worth noting that the risk of HIV infection for male TB patients was 2.947 times (95% CI [2.178, 3.988] than that of female patients. Han ethnicity and Uygur ethnicity in urban region accounted for a large proportion of total TB and TB/HIV co-infection cases. Most of the TB cases of minorities in Urumqi showed a statistically significant increase in risk of HIV infection than Han ethnicity in Urumqi. In addition, the spatial distribution of TB epidemic and TB/HIV co-infection epidemic was highly skewed. Most of the local clusters were located in urban area and rural-urban continuum where showed an increase in risk of TB and TB/HIV

  6. The Impact of HIV/AIDS Epidemic on the Choice of Specialties ...

    African Journals Online (AJOL)

    The Impact of HIV/AIDS Epidemic on the Choice of Specialties among Medical ... satisfaction and favourable work schedule respectively. ... We recommend improvements in the work environment and adherence to universal precautions to

  7. Vaccination intervention on epidemic dynamics in networks

    Science.gov (United States)

    Peng, Xiao-Long; Xu, Xin-Jian; Fu, Xinchu; Zhou, Tao

    2013-02-01

    Vaccination is an important measure available for preventing or reducing the spread of infectious diseases. In this paper, an epidemic model including susceptible, infected, and imperfectly vaccinated compartments is studied on Watts-Strogatz small-world, Barabási-Albert scale-free, and random scale-free networks. The epidemic threshold and prevalence are analyzed. For small-world networks, the effective vaccination intervention is suggested and its influence on the threshold and prevalence is analyzed. For scale-free networks, the threshold is found to be strongly dependent both on the effective vaccination rate and on the connectivity distribution. Moreover, so long as vaccination is effective, it can linearly decrease the epidemic prevalence in small-world networks, whereas for scale-free networks it acts exponentially. These results can help in adopting pragmatic treatment upon diseases in structured populations.

  8. Bayesian projection of life expectancy accounting for the HIV/AIDS epidemic

    Directory of Open Access Journals (Sweden)

    Jessica Godwin

    2017-11-01

    Full Text Available Background: While probabilistic projection methods for projecting life expectancy exist, few account for covariates related to life expectancy. Generalized HIV/AIDS epidemics have a large, immediate negative impact on the life expectancy in a country, but this impact can be mitigated by widespread use of antiretroviral therapy (ART. Thus, projection methods for countries with generalized HIV/AIDS epidemics could be improved by accounting for HIV prevalence, the future course of the epidemic, and ART coverage. Methods: We extend the current Bayesian probabilistic life expectancy projection methods of Raftery et al. (2013 to account for HIV prevalence and adult ART coverage in countries with generalized HIV/AIDS epidemics. Results: We evaluate our method using out-of-sample validation. We find that the proposed method performs better than the method that does not account for HIV prevalence or ART coverage for projections of life expectancy in countries with a generalized epidemic, while projections for countries without an epidemic remain essentially unchanged. Conclusions: In general, our projections show rapid recovery to pre-epidemic life expectancy levels in the presence of widespread ART coverage. After the initial life expectancy recovery, we project a steady rise in life expectancy until the end of the century. Contribution: We develop a simple Bayesian hierarchical model for long-term projections of life expectancy while accounting for HIV/AIDS prevalence and coverage of ART. The method produces well-calibrated projections for countries with generalized HIV/AIDS epidemics up to 2100 while having limited data demands.

  9. Culture, myths and panic: Three decades and beyond with an HIV/AIDS epidemic in Zimbabwe.

    Science.gov (United States)

    Chingwaru, Walter; Vidmar, Jerneja

    2018-02-01

    Zimbabwe is going through a generalised acquired immunodeficiency syndrome (AIDS) epidemic. The first five years of the epidemic (1985-1990) were characterised by lack of medicines against human immunodeficiency virus (HIV), and an exponential increase in prevalence (65-fold) and incidence (13-fold), which were fuelled by high-risk sexual behaviour. The high HIV prevalence, mortality and stigma yielded great fear and panic in the population, which are thought to have led to confusion and hopelessness, and, in turn, increased risky sexual behaviour. The country's government and civil society embarked on HIV awareness campaigns that are claimed to have played a central role in slowing down the epidemic since the mid-2000s. HIV-related mortality then fell by 70% between 2003 and 2013, which is attributed to high uptake of antiretroviral therapy (ART) and prevention of mother-to-child transmission (95%) prophylaxis. However, the epidemic has been characterised by a low paediatric ART coverage (35% in 2011 to 46.12% in 2013). Year 2014 saw an increase in adolescent and young adult HIV prevalence, which may be signalling a rebound of the epidemic. A more holistic approach which deals with the epidemic in its socio-political context is required to effectively lower the country's HIV burden.

  10. Dynamics of epidemic diseases on a growing adaptive network.

    Science.gov (United States)

    Demirel, Güven; Barter, Edmund; Gross, Thilo

    2017-02-10

    The study of epidemics on static networks has revealed important effects on disease prevalence of network topological features such as the variance of the degree distribution, i.e. the distribution of the number of neighbors of nodes, and the maximum degree. Here, we analyze an adaptive network where the degree distribution is not independent of epidemics but is shaped through disease-induced dynamics and mortality in a complex interplay. We study the dynamics of a network that grows according to a preferential attachment rule, while nodes are simultaneously removed from the network due to disease-induced mortality. We investigate the prevalence of the disease using individual-based simulations and a heterogeneous node approximation. Our results suggest that in this system in the thermodynamic limit no epidemic thresholds exist, while the interplay between network growth and epidemic spreading leads to exponential networks for any finite rate of infectiousness when the disease persists.

  11. The spread of HIV in Pakistan: bridging of the epidemic between populations.

    Directory of Open Access Journals (Sweden)

    Muhammad R Khanani

    Full Text Available In the last two decades, 'concentrated epidemics' of human immunodeficiency virus (HIV have established in several high risk groups in Pakistan, including Injecting Drug Users (IDUs and among men who have sex with men (MSM. To explore the transmission patterns of HIV infection in these major high-risk groups of Pakistan, 76 HIV samples were analyzed from MSM, their female spouses and children, along with 26 samples from a previously studied cohort of IDUs. Phylogenetic analysis of HIV gag gene sequences obtained from these samples indicated a substantial degree of intermixing between the IDU and MSM populations, suggesting a bridging of HIV infection from IDUs, via MSM, to the MSM spouses and children. HIV epidemic in Pakistan is now spreading to the female spouses and offspring of bisexual MSM. HIV control and awareness programs must be refocused to include IDUs, MSM, as well as bisexual MSM, and their spouses and children.

  12. Dynamic characteristic analysis of mother to child transmission of HIV in India

    Directory of Open Access Journals (Sweden)

    A. S. Kadi

    2014-01-01

    Full Text Available In this study, a mathematical model of HIV/AIDS mother to child transmission to analyze the effectiveness of prevention of HIV mother to child transmission programmes has been presented. The result reveals that prevention of HIV mother to child transmission programmes focusing only on biological transmission cannot control the increase of the HIV mother to child transmission in India. Hence, to control the HIV MTCT epidemic in India, in spite of strengthening the PMTCT programmes to reduce transmission rates, effective measures should be taken to prevent HIV infection in women of reproductive ages. Since the overall HIV MTCT epidemic is dependent on the HIV incidence in women of reproductive age group, the integration of pediatric HIV model with a detailed model of adult HIV would be investigated in future studies in order to model these dynamics more accurately.

  13. Factors associated with high media coverage of the HIV epidemic in ...

    African Journals Online (AJOL)

    Moreover, journalists and editors are often consciously exploiting the mass media's potential agendasetting function in order to raise attention to HIV and AIDS. Although covering the HIV epidemic has become significantly easier in Lesotho because of government efforts, government and public officials are simultaneously ...

  14. HIV epidemics and prevention responses in Asia and Eastern Europe: lessons to be learned?

    DEFF Research Database (Denmark)

    Bridge, Jamie; Lazarus, Jeff; Atun, Rifat

    2010-01-01

    This paper describes characteristics of the HIV epidemics in Eastern Europe and Central Asia (EECA) and Asia and Central Asia, and draws comparisons between these regions. It focuses on the role that key populations continue to play in HIV transmission in both regions, the challenges that this po...

  15. Has the HIV/AIDS epidemic changed sexual behaviour of high risk ...

    African Journals Online (AJOL)

    Background: Uganda, was the first country in sub-Saharan Africa to reverse its HIV/AIDS epidemic. Long distance drivers, prostitutes and barmaids have been identified as the groups that engage in risky sex, which promotes HIV transmission in Uganda and other countries across the continent. This paper investigates ...

  16. Addressing men and gender diversity in education: a promising solution to the HIV/AIDS epidemic.

    Science.gov (United States)

    Ghajarieh, Amir Biglar Beigi; Kow, Karen Yip Cheng

    2011-04-01

    To date, researchers investigating gender in relation to social issues underscore women and appear to sideline men. Focusing on women in studies concerning sociogender issues may exclude not only men from mainstream research, but also those who do not fit into the binary gender system, including gay, lesbian, bisexual, and transgender (GLBT) people. One area closely related to gender issues is the HIV epidemic. Mainstream discussions of men and other versions of masculinity and femininity including GLBT people in the gender-related studies of the HIV epidemic can decrease the vulnerability of individuals against HIV infections regardless of their biological sex.

  17. Predicting Subnational Ebola Virus Disease Epidemic Dynamics from Sociodemographic Indicators.

    Directory of Open Access Journals (Sweden)

    Linda Valeri

    Full Text Available The recent Ebola virus disease (EVD outbreak in West Africa has spread wider than any previous human EVD epidemic. While individual-level risk factors that contribute to the spread of EVD have been studied, the population-level attributes of subnational regions associated with outbreak severity have not yet been considered.To investigate the area-level predictors of EVD dynamics, we integrated time series data on cumulative reported cases of EVD from the World Health Organization and covariate data from the Demographic and Health Surveys. We first estimated the early growth rates of epidemics in each second-level administrative district (ADM2 in Guinea, Sierra Leone and Liberia using exponential, logistic and polynomial growth models. We then evaluated how these growth rates, as well as epidemic size within ADM2s, were ecologically associated with several demographic and socio-economic characteristics of the ADM2, using bivariate correlations and multivariable regression models.The polynomial growth model appeared to best fit the ADM2 epidemic curves, displaying the lowest residual standard error. Each outcome was associated with various regional characteristics in bivariate models, however in stepwise multivariable models only mean education levels were consistently associated with a worse local epidemic.By combining two common methods-estimation of epidemic parameters using mathematical models, and estimation of associations using ecological regression models-we identified some factors predicting rapid and severe EVD epidemics in West African subnational regions. While care should be taken interpreting such results as anything more than correlational, we suggest that our approach of using data sources that were publicly available in advance of the epidemic or in real-time provides an analytic framework that may assist countries in understanding the dynamics of future outbreaks as they occur.

  18. Review: [corrected] The changing face of the HIV epidemic in sub-Saharan Africa.

    Science.gov (United States)

    Mutevedzi, Portia C; Newell, Marie-Louise

    2014-09-01

    The widespread roll-out of antiretroviral therapy (ART) has substantially changed the face of human immunodeficiency virus (HIV). Timely initiation of ART in HIV-infected individuals dramatically reduces mortality and improves employment rates to levels prior to HIV infection. Recent findings from several studies have shown that ART reduces HIV transmission risk even with modest ART coverage of the HIV-infected population and imperfect ART adherence. While condoms are highly effective in the prevention of HIV acquisition, they are compromised by low and inconsistent usage; male medical circumcision substantially reduces HIV transmission but uptake remains relatively low; ART during pregnancy, delivery and breastfeeding can virtually eliminate mother-to-child transmission but implementation is challenging, especially in resource-limited settings. The current HIV prevention recommendations focus on a combination of preventions approach, including ART as treatment or pre- or post-exposure prophylaxis together with condoms, circumcision and sexual behaviour modification. Improved survival in HIV-infected individuals and reduced HIV transmission risk is beginning to result in limited HIV incidence decline at population level and substantial increases in HIV prevalence. However, achievements in HIV treatment and prevention are threatened by the challenges of lifelong adherence to preventive and therapeutic methods and by the ageing of the HIV-infected cohorts potentially complicating HIV management. Although current thinking suggests prevention of HIV transmission through early detection of infection immediately followed by ART could eventually result in elimination of the HIV epidemic, controversies remain as to whether we can treat our way out of the HIV epidemic. © 2014 John Wiley & Sons Ltd.

  19. Modelling the dynamics of nonendemic epidemics

    International Nuclear Information System (INIS)

    Ramani, A.; Grammaticos, B.; Satsuma, J.

    2009-01-01

    We present two models for an epidemic where the individuals are infective over a fixed period of time and which never becomes endemic i.e., no infective individuals remain after the epidemic has run its course. The first model is based on a delay-difference scheme. We show that, as a function of the delay (which corresponds to the period of infectiveness) the percentage of non-infected population varies over a wide range. We present also a variant of our model where the recovery rate follows a Poisson law and obtain a discrete version of the SIR model. We estimate the percentage of non-infected population in the two models, show that they lead to almost the same values and present an explanation of this fact. The second model is based on the assumption that the infection is spread by carriers. Under the hypothesis that the carriers are relatively long-lived, and that the number of the infected ones is a relatively small fraction of the total population of potential carriers, we show that the model reduces to the same version of the discrete SIR obtained by our first model.

  20. Heterogeneity of the HIV epidemic in the general population of Karnataka state, south India

    Directory of Open Access Journals (Sweden)

    Banandur Pradeep

    2011-12-01

    Full Text Available Abstract Background In the context of AVAHAN, the India AIDS Initiative of the Bill & Melinda Gates Foundation, general population surveys (GPS were carried out between 2006 and 2008 in Belgaum (northern, Bellary (mid-state and Mysore (southern districts of Karnataka state, south India. Data from these three surveys were analysed to understand heterogeneity in HIV risk. Methods Outcome variables were the prevalence of HIV and sexually transmitted infections (STIs. Independent variables included age, district, place of residence, along with socio-demographic, medical and behavioural characteristics. Multivariate logistic regression was undertaken to identify characteristics associated with HIV and differences between districts, incorporating survey statistics to consider weights and cluster effects. Results The participation rate was 79.0% for the interview and 72.5% for providing a blood or urine sample that was tested for HIV. Belgaum had the highest overall HIV (1.43% and Herpes simplex type-2 (HSV-2 (16.93% prevalence, and the lowest prevalence of curable STIs. In Belgaum, the HIV epidemic is predominantly rural, and among women. In Bellary, the epidemic is predominantly in urban areas and among men, and HIV prevalence was 1.18%. Mysore had the lowest prevalence of HIV (0.80% and HSV-2 (10.89% and the highest prevalence of curable STIs. Higher HIV prevalence among men was associated with increasing age (p25-29years=11.22,95%CI:1.42-88.74, AOR30-34years=13.13,95%CI:1.67-103.19 and AOR35-39years=11.33,95%CI:1.32-96.83, having more than one lifetime sexual partner (AOR=4.61,95%CI:1.26-16.91 and having ever used a condom (AOR=3.32,95%CI:1.38-7.99. Having a dissolved marriage (being widowed/divorced/separated was the strongest predictor (AOR=10.98,95%CI: 5.35-22.57 of HIV among women. Being a muslim woman was associated with lower HIV prevalence (AOR=0.27,95%CI:0.08-0.87. Conclusion The HIV epidemic in Karnataka shows considerable heterogeneity

  1. Genetic and phylogenetic evolution of HIV-1 in a low subtype heterogeneity epidemic: the Italian example

    Directory of Open Access Journals (Sweden)

    Tornesello Maria

    2007-05-01

    Full Text Available Abstract The Human Immunodeficiency Virus type 1 (HIV-1 is classified into genetic groups, subtypes and sub-subtypes which show a specific geographic distribution pattern. The HIV-1 epidemic in Italy, as in most of the Western Countries, has traditionally affected the Intra-venous drug user (IDU and Homosexual (Homo risk groups and has been sustained by the genetic B subtype. In the last years, however, the HIV-1 transmission rate among heterosexuals has dramatically increased, becoming the prevalent transmission route. In fact, while the traditional risk groups have high levels of knowledge and avoid high-risk practices, the heterosexuals do not sufficiently perceive the risk of HIV-1 infection. This misperception, linked to the growing number of immigrants from non-Western Countries, where non-B clades and circulating recombinant forms (CRFs are prevalent, is progressively introducing HIV-1 variants of non-B subtype in the Italian epidemic. This is in agreement with reports from other Western European Countries. In this context, the Italian HIV-1 epidemic is still characterized by low subtype heterogeneity and represents a paradigmatic example of the European situation. The continuous molecular evolution of the B subtype HIV-1 isolates, characteristic of a long-lasting epidemic, together with the introduction of new subtypes as well as recombinant forms may have significant implications for diagnostic, treatment, and vaccine development. The study and monitoring of the genetic evolution of the HIV-1 represent, therefore, an essential strategy for controlling the local as well as global HIV-1 epidemic and for developing efficient preventive and therapeutic strategies.

  2. Hybrid epidemic spreading - from Internet worms to HIV infection

    OpenAIRE

    Zhang, C.

    2015-01-01

    Epidemic phenomena are ubiquitous, ranging from infectious diseases, computer viruses, to information dissemination. Epidemics have traditionally been studied as a single spreading process, either in a fully mixed population or on a network. Many epidemics, however, are hybrid, employing more than one spreading mechanism. For example, the Internet worm Conficker spreads locally targeting neighbouring computers in local networks as well as globally by randomly probing any computer on the Inter...

  3. The contributing role of tourism in the HIV/AIDS epidemic in the Caribbean.

    Science.gov (United States)

    Orisatoki, R O; Oguntibeju, O O; Truter, E J

    2009-01-01

    The first confirmed case of HIV/AIDS in the Caribbean was reported in 1982, however a recent report by UNAIDS shows that the epidemic has risen to over 250,000 persons living with the virus with the highest prevalence rates shown to be in the Dominican Republic and Haiti. Various factors ranging from commercial sex trading to unsafe injection employed for drug abuse have been identified to play a contributing role in this increase. Also, the role and impact of tourism on the spread of HIV infection has been reported. Due to concerns shown by countries and territories who are dependent on tourism and that they rank amongst the most highly affected by HIV/AIDS in the region, this paper endeavours to examine the impact of HIV/AIDS and the contributing role of tourism to HIV/AIDS epidemic in the Caribbean.

  4. Adding fuel to the fire: alcohol's effect on the HIV epidemic in Sub-Saharan Africa.

    Science.gov (United States)

    Hahn, Judith A; Woolf-King, Sarah E; Muyindike, Winnie

    2011-09-01

    Alcohol consumption adds fuel to the HIV epidemic in sub-Saharan Africa (SSA). SSA has the highest prevalence of HIV infection and heavy episodic drinking in the world. Alcohol consumption is associated with behaviors such as unprotected sex and poor medication adherence, and biological factors such as increased susceptibility to infection, comorbid conditions, and infectiousness, which may synergistically increase HIV acquisition and onward transmission. Few interventions to decrease alcohol consumption and alcohol-related sexual risk behaviors have been developed or implemented in SSA, and few HIV or health policies or services in SSA address alcohol consumption. Structural interventions, such as regulating the availability, price, and advertising of alcohol, are challenging to implement due to the preponderance of homemade alcohol and beverage industry resistance. This article reviews the current knowledge on how alcohol impacts the HIV epidemic in SSA, summarizes current interventions and policies, and identifies areas for increased research and development.

  5. HIV Among Indigenous peoples: A Review of the Literature on HIV-Related Behaviour Since the Beginning of the Epidemic.

    Science.gov (United States)

    Negin, Joel; Aspin, Clive; Gadsden, Thomas; Reading, Charlotte

    2015-09-01

    From the early days of the HIV epidemic, Indigenous peoples were identified as a population group that experiences social and economic determinants-including colonialism and racism-that increase exposure to HIV. There are now substantial disparities in HIV rates between Indigenous and non-Indigenous peoples in some countries. We conducted a comprehensive literature review to assess the evidence on HIV-related behaviors and determinants in four countries-Australia, Canada, New Zealand and the United States-in which Indigenous peoples share important features of colonization and marginalization. We identified 107 articles over more than 20 years. The review highlights the determinants of HIV-related behaviors including domestic violence, stigma and discrimination, and injecting drug use. Many of the factors associated with HIV risk also contribute to mistrust of health services, which in turn contributes to poor HIV and health outcomes among Indigenous peoples.

  6. HIV type 2 epidemic in Spain: challenges and missing opportunities.

    Science.gov (United States)

    de Mendoza, Carmen; Cabezas, Teresa; Caballero, Estrella; Requena, Silvia; Amengual, María J; Peñaranda, María; Sáez, Ana; Tellez, Raquel; Lozano, Ana B; Treviño, Ana; Ramos, José M; Pérez, José L; Barreiro, Pablo; Soriano, Vicente

    2017-06-19

    : HIV type 2 (HIV-2) is a neglected virus despite estimates of 1-2 million people infected worldwide. HIV-2 is less efficiently transmitted than HIV-1 by sex and from mother to child. Although AIDS may develop in HIV-2 carriers, it takes longer than in HIV-1-infected patients. In contrast with HIV-1 infection, there is no global pandemic caused by HIV-2, as the virus is largely confined to West Africa. In a less extent and due to socioeconomic ties and wars, HIV-2 is prevalent in Portugal and its former colonies in Brazil, India, Mozambique and Angola. Globally, HIV-2 infections are steadily declining over time. A total of 338 cases of HIV-2 infection had been reported at the Spanish HIV-2 registry until December 2016, of whom 63% were men. Overall 72% were sub-Saharan Africans, whereas 16% were native Spaniards. Dual HIV-1 and HIV-2 coinfection was found in 9% of patients. Heterosexual contact was the most likely route of HIV-2 acquisition in more than 90% of cases. Roughly one-third presented with CD4 cell counts less than 200 cells/μl and/or AIDS clinical events. Plasma HIV-2 RNA was undetectable at baseline in 40% of patients. To date, one-third of HIV-2 carriers have received antiretroviral therapy, using integrase inhibitors 32 individuals. New diagnoses of HIV-2 in Spain have remained stable since 2010 with an average of 15 cases yearly. Illegal immigration from Northwestern African borders accounts for over 75% of new HIV-2 diagnoses. Given the relatively large community of West Africans already living in Spain and the continuous flux of immigration from endemic regions, HIV-2 infection either alone or as coinfection with HIV-1 should be excluded once in all HIV-seroreactive persons, especially when showing atypical HIV serological profiles, immunovirological disconnect (CD4 cell count loss despite undetectable HIV-1 viremia) and/or high epidemiological risks (birth in or sex partners from endemic regions).

  7. HIV-1 CRF_BC recombinants infection in China: molecular epidemic and characterizations.

    Science.gov (United States)

    Ouyang, Yabo; Shao, Yiming; Ma, Liying

    2012-03-01

    CRF_BC recombinant strains were first identified in China and are one of the most prevalent and characteristically unique HIV-1 subtypes across China. Here we aim to review the published data about HIV-1 CRF_BC recombinant strains epidemic in China and to characterize the genetics, biology and drug resistance of this virus. This study may help to better understand the current situation of HIV-1 CRF_BC prevalence and facilitate the development of vaccines and more efficient anti-HIV-1 regimens in China.

  8. Agent-based and phylogenetic analyses reveal how HIV-1 moves between risk groups: injecting drug users sustain the heterosexual epidemic in Latvia

    Science.gov (United States)

    Graw, Frederik; Leitner, Thomas; Ribeiro, Ruy M.

    2012-01-01

    Injecting drug users (IDU) are a driving force for the spread of HIV-1 in Latvia and other Baltic States, accounting for a majority of cases. However, in recent years, heterosexual cases have increased disproportionately. It is unclear how the changes in incidence patterns in Latvia can be explained, and how important IDU are for the heterosexual sub-epidemic. We introduce a novel epidemic model and use phylogenetic analyses in parallel to examine the spread of HIV-1 in Latvia between 1987 and 2010. Using a hybrid framework with a mean-field description for the susceptible population and an agent-based model for the infecteds, we track infected individuals and follow transmission histories dynamically formed during the simulation. The agent-based simulations and the phylogenetic analysis show that more than half of the heterosexual transmissions in Latvia were caused by IDU, which sustain the heterosexual epidemic. Indeed, we find that heterosexual clusters are characterized by short transmission chains with up to 63% of the chains dying out after the first introduction. In the simulations, the distribution of transmission chain sizes follows a power law distribution, which is confirmed by the phylogenetic data. Our models indicate that frequent introductions reduced the extinction probability of an autonomously spreading heterosexual HIV-1 epidemic, which now has the potential to dominate the spread of the overall epidemic in the future. Furthermore, our model shows that social heterogeneity of the susceptible population can explain the shift in HIV-1 incidence in Latvia over the course of the epidemic. Thus, the decrease in IDU incidence may be due to local heterogeneities in transmission, rather than the implementation of control measures. Increases in susceptibles, through social or geographic movement of IDU, could lead to a boost in HIV-1 infections in this risk group. Targeting individuals that bridge social groups would help prevent further spread of the

  9. The hepatitis C epidemic among HIV-positive MSM

    DEFF Research Database (Denmark)

    van der Helm, Jannie J; Prins, Maria; del Amo, Julia

    2011-01-01

    Outbreaks of acute hepatitis C virus (HCV) infection among HIV-infected MSM have been described since 2000. However, phylogenetic analysis suggests that the spread of HCV started around 1996. We estimated the incidence of HCV in HIV-infected MSM with well estimated dates of HIV seroconversion from...

  10. Women with HIV in Indonesia: are they bridging a concentrated epidemic to the wider community?

    Science.gov (United States)

    Rahmalia, Annisa; Wisaksana, Rudi; Meijerink, Hinta; Indrati, Agnes R; Alisjahbana, Bachti; Roeleveld, Nel; van der Ven, Andre J A M; Laga, Marie; van Crevel, Reinout

    2015-12-09

    Male injecting drug users drove the onset of the HIV epidemic in Indonesia but over time more women have been diagnosed. We examined the relative proportion of female patients in an HIV cohort and characterized their probable transmission route and reproductive profile. Prospective cohort study in a referral hospital in West Java. Interviews with standardized questionnaires, physical and laboratory examinations were done for 2622 individuals enrolled in HIV care between 2007 and 2012. The proportion of women in this cohort was compared with national estimates. The general characteristics of HIV-infected women and men as well as the sexual and reproductive health of HIV-infected women were described. The proportion of female patients enrolled in HIV care increased from 22.2 % in 2007 to 38.3 % in 2012, in line with national estimates. Women were younger than men, fewer reported a history of IDU (16.1 vs. 73.8 %, p women were in their reproductive age, had children, and were not using contraceptives at the time of enrolment. HIV-infected women in Indonesia have specific characteristics that differ them from women in the general population. Further research to elucidate the characteristics of women exposed to HIV, their access to testing and care and sexual and reproductive needs can help reduce transmission to women and children in the context of concentrated HIV epidemic in Indonesia.

  11. The Genetic Diversity and Evolution of HIV-1 Subtype B Epidemic in Puerto Rico

    Directory of Open Access Journals (Sweden)

    Pablo López

    2015-12-01

    Full Text Available HIV-1 epidemics in Caribbean countries, including Puerto Rico, have been reported to be almost exclusively associated with the subtype B virus (HIV-1B. However, while HIV infections associated with other clades have been only sporadically reported, no organized data exist to accurately assess the prevalence of non-subtype B HIV-1 infection. We analyzed the nucleotide sequence data of the HIV pol gene associated with HIV isolates from Puerto Rican patients. The sequences (n = 945 were obtained from our “HIV Genotyping” test file, which has been generated over a period of 14 years (2001–2014. REGA subtyping tool found the following subtypes: B (90%, B-like (3%, B/D recombinant (6%, and D/B recombinant (0.6%. Though there were fewer cases, the following subtypes were also found (in the given proportions: A1B (0.3%, BF1 (0.2%, subtype A (01-AE (0.1%, subtype A (A2 (0.1%, subtype F (12BF (0.1%, CRF-39 BF-like (0.1%, and others (0.1%. Some of the recombinants were identified as early as 2001. Although the HIV epidemic in Puerto Rico is primarily associated with HIV-1B virus, our analysis uncovered the presence of other subtypes. There was no indication of subtype C, which has been predominantly associated with heterosexual transmission in other parts of the world.

  12. The Genetic Diversity and Evolution of HIV-1 Subtype B Epidemic in Puerto Rico.

    Science.gov (United States)

    López, Pablo; Rivera-Amill, Vanessa; Rodríguez, Nayra; Vargas, Freddie; Yamamura, Yasuhiro

    2015-12-23

    HIV-1 epidemics in Caribbean countries, including Puerto Rico, have been reported to be almost exclusively associated with the subtype B virus (HIV-1B). However, while HIV infections associated with other clades have been only sporadically reported, no organized data exist to accurately assess the prevalence of non-subtype B HIV-1 infection. We analyzed the nucleotide sequence data of the HIV pol gene associated with HIV isolates from Puerto Rican patients. The sequences (n = 945) were obtained from our "HIV Genotyping" test file, which has been generated over a period of 14 years (2001-2014). REGA subtyping tool found the following subtypes: B (90%), B-like (3%), B/D recombinant (6%), and D/B recombinant (0.6%). Though there were fewer cases, the following subtypes were also found (in the given proportions): A1B (0.3%), BF1 (0.2%), subtype A (01-AE) (0.1%), subtype A (A2) (0.1%), subtype F (12BF) (0.1%), CRF-39 BF-like (0.1%), and others (0.1%). Some of the recombinants were identified as early as 2001. Although the HIV epidemic in Puerto Rico is primarily associated with HIV-1B virus, our analysis uncovered the presence of other subtypes. There was no indication of subtype C, which has been predominantly associated with heterosexual transmission in other parts of the world.

  13. History of the HIV epidemic and response in Swaziland

    African Journals Online (AJOL)

    that self-stigma, multiple concurrent partnerships and short-term relationships, decision on condom use and ... This prevents MSM from seeking health services. To .... 90-90-90: An ambitious treatment target to help end the AIDS epidemic.

  14. A simple model of HIV epidemic in Italy: The role of the antiretroviral treatment.

    Science.gov (United States)

    Papa, Federico; Binda, Francesca; Felici, Giovanni; Franzetti, Marco; Gandolfi, Alberto; Sinisgalli, Carmela; Balotta, Claudia

    2018-02-01

    In the present paper we propose a simple time-varying ODE model to describe the evolution of HIV epidemic in Italy. The model considers a single population of susceptibles, without distinction of high-risk groups within the general population, and accounts for the presence of immigration and emigration, modelling their effects on both the general demography and the dynamics of the infected subpopulations. To represent the intra-host disease progression, the untreated infected population is distributed over four compartments in cascade according to the CD4 counts. A further compartment is added to represent infected people under antiretroviral therapy. The per capita exit rate from treatment, due to voluntary interruption or failure of therapy, is assumed variable with time. The values of the model parameters not reported in the literature are assessed by fitting available epidemiological data over the decade 2003÷2012. Predictions until year 2025 are computed, enlightening the impact on the public health of the early initiation of the antiretroviral therapy. The benefits of this change in the treatment eligibility consist in reducing the HIV incidence rate, the rate of new AIDS cases, and the rate of death from AIDS. Analytical results about properties of the model in its time-invariant form are provided, in particular the global stability of the equilibrium points is established either in the absence and in the presence of infected among immigrants.

  15. Sudden transitions in coupled opinion and epidemic dynamics with vaccination

    Science.gov (United States)

    Pires, Marcelo A.; Oestereich, André L.; Crokidakis, Nuno

    2018-05-01

    This work consists of an epidemic model with vaccination coupled with an opinion dynamics. Our objective was to study how disease risk perception can influence opinions about vaccination and therefore the spreading of the disease. Differently from previous works we have considered continuous opinions. The epidemic spreading is governed by an SIS-like model with an extra vaccinated state. In our model individuals vaccinate with a probability proportional to their opinions. The opinions change due to peer influence in pairwise interactions. The epidemic feedback to the opinion dynamics acts as an external field increasing the vaccination probability. We performed Monte Carlo simulations in fully-connected populations. Interestingly we observed the emergence of a first-order phase transition, besides the usual active-absorbing phase transition presented in the SIS model. Our simulations also show that with a certain combination of parameters, an increment in the initial fraction of the population that is pro-vaccine has a twofold effect: it can lead to smaller epidemic outbreaks in the short term, but it also contributes to the survival of the chain of infections in the long term. Our results also suggest that it is possible that more effective vaccines can decrease the long-term vaccine coverage. This is a counterintuitive outcome, but it is in line with empirical observations that vaccines can become a victim of their own success.

  16. Dynamics of cholera epidemics with impulsive vaccination and disinfection.

    Science.gov (United States)

    Sisodiya, Omprakash Singh; Misra, O P; Dhar, Joydip

    2018-04-01

    Waterborne diseases have a tremendous influence on human life. The contaminated drinking water causes water-borne disease like cholera. Pulse vaccination is an important and effective strategy for the elimination of infectious diseases. A waterborne disease like cholera can also be controlled by using impulse technique. In this paper, we have proposed a delayed SEIRB epidemic model with impulsive vaccination and disinfection. We have studied the pulse vaccination strategy and sanitation to control the cholera disease. The existence and stability of the disease-free and endemic periodic solution are investigated both analytically and numerically. It is shown that there exists an infection-free periodic solution, using the impulsive dynamical system defined by the stroboscopic map. It is observed that the infection-free periodic solution is globally attractive when the impulse period is less than some critical value. From the analysis of the model, we have obtained a sufficient condition for the permanence of the epidemic with pulse vaccination. The main highlight of this paper is to introduce impulse technique along with latent period into the SEIRB epidemic model to investigate the role of pulse vaccination and disinfection on the dynamics of the cholera epidemics. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. CROI 2018: Epidemic Trends and Advances in HIV Prevention.

    Science.gov (United States)

    Buchbinder, Susan P; Liu, Albert Y

    2018-05-01

    At the 2018 Conference on Retroviruses and Opportunistic Infections, trends in and risk factors for in HIV infection were highlighted. In the United States, new HIV diagnoses are highest in the South and among African Americans and are increasing in rural areas. Youth remain highly vulnerable to HIV infection globally. The epidemiology of HIV infections among people who inject drugs is changing, with overdose deaths, a major public health concern. Phylogenetics are being used to identify HIV transmission clusters and hotspots, which can inform prevention efforts. Vaginal microbial dysbiosis and proteomic alterations are associated with increased risk of HIV acquisition, as are the pregnancy and postpartum periods. HIV testing is a central first step for the HIV care and treatment continua, and several innovative strategies to expand HIV testing coverage and frequency show promise. Preexposure prophylaxis (PrEP) uptake is rapidly increasing in some cities, with reductions of new infections at the population level, but use is lower among African Americans and Latinos, youth, cis- and transgender women, and people who inject drugs. PrEP continuation remains a challenge. Two open-label extension studies of the dapivirine vaginal ring demonstrated high uptake, adherence, and reduced HIV infections. Several novel systemic and topical prevention agents show promise in non-human primates.

  18. Five Myths about the HIV Epidemic in Asia

    OpenAIRE

    Godwin, Peter; O'Farrell, Nigel; Fylkesnes, Knut; Misra, Sujaya

    2006-01-01

    It is widely recognised that the huge population sizes of many Asian countries mean that although national HIV prevalence levels are still very low, very large absolute numbers of people are being infected each year with HIV [1]. Urgent responses are required; the effective responses by countries such as Thailand and Cambodia have shown how much can be done. As implementers who have worked with HIV/AIDS programmes in several countries in the region, we recognise the public health and welf...

  19. Modeling age-specific mortality for countries with generalized HIV epidemics.

    Directory of Open Access Journals (Sweden)

    David J Sharrow

    Full Text Available In a given population the age pattern of mortality is an important determinant of total number of deaths, age structure, and through effects on age structure, the number of births and thereby growth. Good mortality models exist for most populations except those experiencing generalized HIV epidemics and some developing country populations. The large number of deaths concentrated at very young and adult ages in HIV-affected populations produce a unique 'humped' age pattern of mortality that is not reproduced by any existing mortality models. Both burden of disease reporting and population projection methods require age-specific mortality rates to estimate numbers of deaths and produce plausible age structures. For countries with generalized HIV epidemics these estimates should take into account the future trajectory of HIV prevalence and its effects on age-specific mortality. In this paper we present a parsimonious model of age-specific mortality for countries with generalized HIV/AIDS epidemics.The model represents a vector of age-specific mortality rates as the weighted sum of three independent age-varying components. We derive the age-varying components from a Singular Value Decomposition of the matrix of age-specific mortality rate schedules. The weights are modeled as a function of HIV prevalence and one of three possible sets of inputs: life expectancy at birth, a measure of child mortality, or child mortality with a measure of adult mortality. We calibrate the model with 320 five-year life tables for each sex from the World Population Prospects 2010 revision that come from the 40 countries of the world that have and are experiencing a generalized HIV epidemic. Cross validation shows that the model is able to outperform several existing model life table systems.We present a flexible, parsimonious model of age-specific mortality for countries with generalized HIV epidemics. Combined with the outputs of existing epidemiological and

  20. Expanding HIV testing efforts in concentrated epidemic settings: a population-based survey from rural Vietnam.

    Directory of Open Access Journals (Sweden)

    Anastasia Pharris

    Full Text Available BACKGROUND: To improve HIV prevention and care programs, it is important to understand the uptake of HIV testing and to identify population segments in need of increased HIV testing. This is particularly crucial in countries with concentrated HIV epidemics, where HIV prevalence continues to rise in the general population. This study analyzes determinants of HIV testing in a rural Vietnamese population in order to identify potential access barriers and areas for promoting HIV testing services. METHODS: A population-based cross-sectional survey of 1874 randomly sampled adults was linked to pregnancy, migration and economic cohort data from a demographic surveillance site (DSS. Multivariate logistic regression analysis was used to determine which factors were associated with having tested for HIV. RESULTS: The age-adjusted prevalence of ever-testing for HIV was 7.6%; however 79% of those who reported feeling at-risk of contracting HIV had never tested. In multivariate analysis, younger age (aOR 1.85, 95% CI 1.14-3.01, higher economic status (aOR 3.4, 95% CI 2.21-5.22, and semi-urban residence (aOR 2.37, 95% CI 1.53-3.66 were associated with having been tested for HIV. HIV testing rates did not differ between women of reproductive age who had recently been pregnant and those who had not. CONCLUSIONS: We found low testing uptake (6% among pregnant women despite an existing prevention of mother-to-child HIV testing policy, and lower-than-expected testing among persons who felt that they were at-risk of HIV. Poverty and residence in a more geographically remote location were associated with less HIV testing. In addition to current HIV testing strategies focusing on high-risk groups, we recommend targeting HIV testing in concentrated HIV epidemic settings to focus on a scaled-up provision of antenatal testing. Additional recommendations include removing financial and geographic access barriers to client-initiated testing, and encouraging provider

  1. Expanding HIV testing efforts in concentrated epidemic settings: a population-based survey from rural Vietnam.

    Science.gov (United States)

    Pharris, Anastasia; Nguyen, Thi Kim Chuc; Tishelman, Carol; Brugha, Ruairí; Nguyen, Phuong Hoa; Thorson, Anna

    2011-01-11

    To improve HIV prevention and care programs, it is important to understand the uptake of HIV testing and to identify population segments in need of increased HIV testing. This is particularly crucial in countries with concentrated HIV epidemics, where HIV prevalence continues to rise in the general population. This study analyzes determinants of HIV testing in a rural Vietnamese population in order to identify potential access barriers and areas for promoting HIV testing services. A population-based cross-sectional survey of 1874 randomly sampled adults was linked to pregnancy, migration and economic cohort data from a demographic surveillance site (DSS). Multivariate logistic regression analysis was used to determine which factors were associated with having tested for HIV. The age-adjusted prevalence of ever-testing for HIV was 7.6%; however 79% of those who reported feeling at-risk of contracting HIV had never tested. In multivariate analysis, younger age (aOR 1.85, 95% CI 1.14-3.01), higher economic status (aOR 3.4, 95% CI 2.21-5.22), and semi-urban residence (aOR 2.37, 95% CI 1.53-3.66) were associated with having been tested for HIV. HIV testing rates did not differ between women of reproductive age who had recently been pregnant and those who had not. We found low testing uptake (6%) among pregnant women despite an existing prevention of mother-to-child HIV testing policy, and lower-than-expected testing among persons who felt that they were at-risk of HIV. Poverty and residence in a more geographically remote location were associated with less HIV testing. In addition to current HIV testing strategies focusing on high-risk groups, we recommend targeting HIV testing in concentrated HIV epidemic settings to focus on a scaled-up provision of antenatal testing. Additional recommendations include removing financial and geographic access barriers to client-initiated testing, and encouraging provider-initiated testing of those who believe that they are at-risk of

  2. Evolving uses of oral reverse transcriptase inhibitors in the HIV-1 epidemic: From treatment to prevention

    NARCIS (Netherlands)

    R.K. Gupta (Ravindra); D.A.M.C. van de Vijver (David); S. Manicklal (Sheetal); M.A. Wainberg (Mark)

    2013-01-01

    textabstractThe HIV epidemic continues unabated, with no highly effective vaccine and no cure. Each new infection has significant economic, social and human costs and prevention efforts are now as great a priority as global antiretroviral therapy (ART) scale up. Reverse transcriptase inhibitors, the

  3. Complex agent networks explaining the HIV epidemic among homosexual men in Amsterdam

    NARCIS (Netherlands)

    Mei, S.; Sloot, P.M.A.; Quax, R.; Zhu, Y.; Wang, W.

    2010-01-01

    Simulating the spreading of the human immunodeficiency virus (HIV) epidemic requires a detailed description of the population network, especially for small populations in which individuals can be represented in detail and accuracy. In this paper, we introduce the concept of a complex agent network

  4. Estimating incidence from prevalence in generalised HIV epidemics: methods and validation.

    Directory of Open Access Journals (Sweden)

    Timothy B Hallett

    2008-04-01

    Full Text Available HIV surveillance of generalised epidemics in Africa primarily relies on prevalence at antenatal clinics, but estimates of incidence in the general population would be more useful. Repeated cross-sectional measures of HIV prevalence are now becoming available for general populations in many countries, and we aim to develop and validate methods that use these data to estimate HIV incidence.Two methods were developed that decompose observed changes in prevalence between two serosurveys into the contributions of new infections and mortality. Method 1 uses cohort mortality rates, and method 2 uses information on survival after infection. The performance of these two methods was assessed using simulated data from a mathematical model and actual data from three community-based cohort studies in Africa. Comparison with simulated data indicated that these methods can accurately estimates incidence rates and changes in incidence in a variety of epidemic conditions. Method 1 is simple to implement but relies on locally appropriate mortality data, whilst method 2 can make use of the same survival distribution in a wide range of scenarios. The estimates from both methods are within the 95% confidence intervals of almost all actual measurements of HIV incidence in adults and young people, and the patterns of incidence over age are correctly captured.It is possible to estimate incidence from cross-sectional prevalence data with sufficient accuracy to monitor the HIV epidemic. Although these methods will theoretically work in any context, we have able to test them only in southern and eastern Africa, where HIV epidemics are mature and generalised. The choice of method will depend on the local availability of HIV mortality data.

  5. Nonlinear dynamics of avian influenza epidemic models.

    Science.gov (United States)

    Liu, Sanhong; Ruan, Shigui; Zhang, Xinan

    2017-01-01

    Avian influenza is a zoonotic disease caused by the transmission of the avian influenza A virus, such as H5N1 and H7N9, from birds to humans. The avian influenza A H5N1 virus has caused more than 500 human infections worldwide with nearly a 60% death rate since it was first reported in Hong Kong in 1997. The four outbreaks of the avian influenza A H7N9 in China from March 2013 to June 2016 have resulted in 580 human cases including 202 deaths with a death rate of nearly 35%. In this paper, we construct two avian influenza bird-to-human transmission models with different growth laws of the avian population, one with logistic growth and the other with Allee effect, and analyze their dynamical behavior. We obtain a threshold value for the prevalence of avian influenza and investigate the local or global asymptotical stability of each equilibrium of these systems by using linear analysis technique or combining Liapunov function method and LaSalle's invariance principle, respectively. Moreover, we give necessary and sufficient conditions for the occurrence of periodic solutions in the avian influenza system with Allee effect of the avian population. Numerical simulations are also presented to illustrate the theoretical results. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Phylodynamic and Phylogeographic Patterns of the HIV Type 1 Subtype F1 Parenteral Epidemic in Romania

    Science.gov (United States)

    Hué, Stéphane; Buckton, Andrew J.; Myers, Richard E.; Duiculescu, Dan; Ene, Luminita; Oprea, Cristiana; Tardei, Gratiela; Rugina, Sorin; Mardarescu, Mariana; Floch, Corinne; Notheis, Gundula; Zöhrer, Bettina; Cane, Patricia A.; Pillay, Deenan

    2012-01-01

    Abstract In the late 1980s an HIV-1 epidemic emerged in Romania that was dominated by subtype F1. The main route of infection is believed to be parenteral transmission in children. We sequenced partial pol coding regions of 70 subtype F1 samples from children and adolescents from the PENTA-EPPICC network of which 67 were from Romania. Phylogenetic reconstruction using the sequences and other publically available global subtype F sequences showed that 79% of Romanian F1 sequences formed a statistically robust monophyletic cluster. The monophyletic cluster was epidemiologically linked to parenteral transmission in children. Coalescent-based analysis dated the origins of the parenteral epidemic to 1983 [1981–1987; 95% HPD]. The analysis also shows that the epidemic's effective population size has remained fairly constant since the early 1990s suggesting limited onward spread of the virus within the population. Furthermore, phylogeographic analysis suggests that the root location of the parenteral epidemic was Bucharest. PMID:22251065

  7. Rape and HIV post-exposure prophylaxis: addressing the dual epidemics in South Africa.

    Science.gov (United States)

    Kim, Julia C; Martin, Lorna J; Denny, Lynette

    2003-11-01

    In South Africa, a country notable for both a rapidly escalating AIDS epidemic and high levels of sexual violence, the issue of HIV post-exposure prophylaxis (PEP) following rape has recently come to the fore, and a policy supporting provision of PEP has been approved by the national government. This paper compares the conditions for providing PEP in Europe and North America with the conditions faced by two initiatives in South Africa, one serving a primarily rural base, and one urban. It is based on a review of the literature on sexual violence in South Africa and use of PEP following occupational and non-occupational exposure. It incorporates perspectives from in-depth interviews in 2000 with 18 key informants, including survivors of sexual violence, gender and HIV activists, domestic violence NGOs, rape crisis centres, physicians, lawyers, researchers and HIV/AIDS advisors in the Department of Health. The paper argues that given the scientific evidence for PEP, and the nature of the dual epidemics of HIV and sexual violence in South Africa, the public health and social justice rationale for implementing PEP equals and indeed exceeds that put forward in industrialised countries. However, delays in accessing PEP caused by the public justice system and lack of training for service providers constitute significant obstacles to effective implementation. In this respect, provision of PEP presents an opportunity to reform and strengthen existing services for post-rape care and to link attention to the epidemic of sexual violence to HIV/AIDS prevention.

  8. The HIV/AIDS Epidemic in the Dominican Republic: Key Contributing Factors.

    Science.gov (United States)

    Rojas, Patria; Malow, Robert; Ruffin, Beverly; Rothe, Eugenio M; Rosenberg, Rhonda

    2011-01-01

    This article reviews HIV/AIDS epidemiological data and recent research conducted in the Dominican Republic, with a focus on explaining the variability in estimated seroincidence and prevalence within the country. HIV seroprevalence estimates range from 1.0% (in the general population) to 11.0% among men who have sex with men (MSM). Some have indicated that the highest HIV seroprevalence occurs in Haitian enclaves called bateyes (US Agency for International Development [USAID], 2008), which are migrant worker shantytowns primarily serving the sugar industry in the Dominican Republic. Others report higher or comparable rates to the bateyes in areas related to the tourism and sex industries. As in other Caribbean and Latin American countries, reported HIV transmission in the Dominican Republic is predominantly due to unprotected heterosexual sex and the infection rate has been increasing disproportionally among women. The Dominican Republic represents two thirds of the Hispaniola island; the western one third is occupied by Haiti, the nation with the highest HIV prevalence in the western hemisphere. Although data is limited, it shows important differences in seroprevalence and incidence between these two countries, but commonalities such as poverty, gender inequalities, and stigma appear to be pivotal factors driving the epidemic. This article will discuss these and other factors that may contribute to the HIV epidemic in the Dominican Republic, as well as highlight the gaps in the literature and provide recommendations to guide further work in this area, particularly in the role of governance in sustainable HIV prevention.

  9. Timing of the HIV-1 subtype C epidemic in Ethiopia based on early virus strains and subsequent virus diversification

    NARCIS (Netherlands)

    Abebe, A.; Lukashov, V. V.; Pollakis, G.; Kliphuis, A.; Fontanet, A. L.; Goudsmit, J.; Rinke de Wit, T. F.

    2001-01-01

    OBJECTIVE: To trace the introduction of HIV-1 subtype C into Ethiopia based on virus diversification during the epidemic. DESIGN: A set of 474 serum samples obtained in Ethiopia in 1982-1985 was tested for HIV-1. HIV-1 env gp120 V3 and gag or pol regions were sequenced and analysed together with

  10. Monitoring HIV Epidemic in Pregnant Women: Are the Current Measures Enough?

    Science.gov (United States)

    Sarkate, Purva; Paranjpe, Supriya; Ingole, Nayana; Mehta, Preeti

    2015-01-01

    Introduction. Burden of HIV in pregnant women follows overall epidemic in India. Hence, it is imperative that prevalence calculations in this group be accurate. The present study was carried out to determine prevalence of HIV in pregnant women attending our hospital, to determine trend of HIV infection and to compare our results with reported prevalence. Methods. All pregnant women are routinely counselled for HIV testing using opt-out strategy. Year-wise positivity and trend were determined in these patients over a period of five years. The positivity in different age groups was determined. Results. 31,609 women were tested of which 279 (0.88%) were positive. Positivity showed a declining trend over study period and significant quadratic trend (biphasic, P program data is critical for HIV programming and resource allocation.

  11. Dynamic malware containment under an epidemic model with alert

    Science.gov (United States)

    Zhang, Tianrui; Yang, Lu-Xing; Yang, Xiaofan; Wu, Yingbo; Tang, Yuan Yan

    2017-03-01

    Alerting at the early stage of malware invasion turns out to be an important complement to malware detection and elimination. This paper addresses the issue of how to dynamically contain the prevalence of malware at a lower cost, provided alerting is feasible. A controlled epidemic model with alert is established, and an optimal control problem based on the epidemic model is formulated. The optimality system for the optimal control problem is derived. The structure of an optimal control for the proposed optimal control problem is characterized under some conditions. Numerical examples show that the cost-efficiency of an optimal control strategy can be enhanced by adjusting the upper and lower bounds on admissible controls.

  12. Population mobility and the changing epidemics of HIV-2 in Portugal

    DEFF Research Database (Denmark)

    Carvalho, A C; Valadas, E; França, L

    2012-01-01

    Portugal is the European country with the highest frequency of HIV-2 infection, which is mainly concentrated in West Africa. The cumulative number of notified HIV-2 infections in Portugal was 1813 by the end of December 2008. To better characterize the dynamics of HIV-2 infection in the country a...... and to obtain data that may be of use in the prevention of the spread of HIV-2, we evaluated a large pooled sample of patients....

  13. Shifting Patterns of the HIV Epidemic in Southwest China: A Case Study Based on Sentinel Surveillance, 1995-2012.

    Science.gov (United States)

    Chow, Eric P F; Gao, Liangmin; Chen, Liang; Jing, Jun; Zhang, Lei

    2015-06-01

    The HIV epidemic is experiencing a rapid shift in transmission profile in China. This study aims to examine the changes in magnitude, transmission pattern, and trend of the HIV epidemic in a typical Southwest Chinese prefecture over the period of 1995-2012. HIV surveillance data from the web-based reporting system were analyzed during this period. We investigated the temporal trends in the changing characteristics of HIV transmission, the HIV disease burden in key affected populations, and assessed the impacts on HIV disease progression due to scale-up of antiretroviral treatment. A total of 3556 HIV/AIDS cases were reported in Yuxi prefecture, Yunnan, over the study period. The number of HIV tests conducted has dramatically increased from 1041 in 1995 to 247,859 in 2012, resulting in a substantial increase in HIV diagnoses from 11 cases to 327 cases over the same period. Since 2005, cumulatively 1250 eligible people living with HIV (PLHIV) have received combination antiretroviral therapy which reduced AIDS disease progression from 9.0% (95% CI: 6.7-11.4%) in 1995 to 0.1% (0-0.3%) in 2012 (ptrend=0.0002). The primary mode of HIV transmission has been shifted from injection sharing (71.9% diagnoses in 1995-2004) to unsafe sexual contacts (82.6% diagnoses in 2012). Yuxi prefecture is experiencing a concentrated but shifting HIV epidemic. Scale-up of HIV testing is essential to effective sentinel surveillance and enhancing early diagnosis and treatment in PLHIV.

  14. Controlling HIV Epidemics among Injection Drug Users: Eight Years of Cross-Border HIV Prevention Interventions in Vietnam and China

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    Hammett, Theodore M.; Des Jarlais, Don C.; Kling, Ryan; Kieu, Binh Thanh; McNicholl, Janet M.; Wasinrapee, Punneeporn; McDougal, J. Stephen; Liu, Wei; Chen, Yi; Meng, Donghua; Huu Nguyen, Tho; Ngoc Hoang, Quyen; Van Hoang, Tren

    2012-01-01

    Introduction HIV in Vietnam and Southern China is driven by injection drug use. We have implemented HIV prevention interventions for IDUs since 2002–2003 in Lang Son and Ha Giang Provinces, Vietnam and Ning Ming County (Guangxi), China. Methods Interventions provide peer education and needle/syringe distribution. Evaluation employed serial cross-sectional surveys of IDUs 26 waves from 2002 to 2011, including interviews and HIV testing. Outcomes were HIV risk behaviors, HIV prevalence and incidence. HIV incidence estimation used two methods: 1) among new injectors from prevalence data; and 2) a capture enzyme immunoassay (BED testing) on all HIV+ samples. Results We found significant declines in drug-related risk behaviors and sharp reductions in HIV prevalence among IDUs (Lang Son from 46% to 23% [pHIV incidence to low levels among new injectors through 36–48 months, then some rebound, particularly in Ning Ming, but BED-based estimates revealed significant reductions in incidence through 96 months. Discussion This is one of the longest studies of HIV prevention among IDUs in Asia. The rebound in incidence among new injectors may reflect sexual transmission. BED-based estimates may overstate incidence (because of false-recent results in patients with long-term infection or on ARV treatment) but adjustment for false-recent results and survey responses on duration of infection generally confirm BED-based incidence trends. Combined trends from the two estimation methods show sharp declines in incidence to low levels. The significant downward trends in all primary outcome measures indicate that the Cross-Border interventions played an important role in bringing HIV epidemics among IDUs under control. The Cross-Border project offers a model of HIV prevention for IDUs that should be considered for large-scale replication. PMID:22952640

  15. Planning horizon affects prophylactic decision-making and epidemic dynamics.

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    Nardin, Luis G; Miller, Craig R; Ridenhour, Benjamin J; Krone, Stephen M; Joyce, Paul; Baumgaertner, Bert O

    2016-01-01

    The spread of infectious diseases can be impacted by human behavior, and behavioral decisions often depend implicitly on a planning horizon-the time in the future over which options are weighed. We investigate the effects of planning horizons on epidemic dynamics. We developed an epidemiological agent-based model (along with an ODE analog) to explore the decision-making of self-interested individuals on adopting prophylactic behavior. The decision-making process incorporates prophylaxis efficacy and disease prevalence with the individuals' payoffs and planning horizon. Our results show that for short and long planning horizons individuals do not consider engaging in prophylactic behavior. In contrast, individuals adopt prophylactic behavior when considering intermediate planning horizons. Such adoption, however, is not always monotonically associated with the prevalence of the disease, depending on the perceived protection efficacy and the disease parameters. Adoption of prophylactic behavior reduces the epidemic peak size while prolonging the epidemic and potentially generates secondary waves of infection. These effects can be made stronger by increasing the behavioral decision frequency or distorting an individual's perceived risk of infection.

  16. Halting HIV/AIDS with avatars and havatars: a virtual world approach to modelling epidemics

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    Smith? Robert J

    2009-11-01

    Full Text Available Abstract Background A major deficit of all approaches to epidemic modelling to date has been the need to approximate or guess at human behaviour in disease-transmission-related contexts. Avatars are generally human-like figures in virtual computer worlds controlled by human individuals. Methods We introduce the concept of a "havatar", which is a (human, avatar pairing. Evidence is mounting that this pairing behaves in virtual contexts much like the human in the pairing might behave in analogous real-world contexts. Results We propose that studies of havatars, in a virtual world, may give a realistic approximation of human behaviour in real-world contexts. If the virtual world approximates the real world in relevant details (geography, transportation, etc., virtual epidemics in that world could accurately simulate real-world epidemics. Havatar modelling of epidemics therefore offers a complementary tool for tackling how best to halt epidemics, including perhaps HIV/AIDS, since sexual behaviour is a significant component of some virtual worlds, such as Second Life. Conclusion Havatars place the control parameters of an epidemic in the hands of each individual. By providing tools that everyone can understand and use, we could democratise epidemiology.

  17. Dynamic properties of epidemic spreading on finite size complex networks

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    Li, Ying; Liu, Yang; Shan, Xiu-Ming; Ren, Yong; Jiao, Jian; Qiu, Ben

    2005-11-01

    The Internet presents a complex topological structure, on which computer viruses can easily spread. By using theoretical analysis and computer simulation methods, the dynamic process of disease spreading on finite size networks with complex topological structure is investigated. On the finite size networks, the spreading process of SIS (susceptible-infected-susceptible) model is a finite Markov chain with an absorbing state. Two parameters, the survival probability and the conditional infecting probability, are introduced to describe the dynamic properties of disease spreading on finite size networks. Our results can help understanding computer virus epidemics and other spreading phenomena on communication and social networks. Also, knowledge about the dynamic character of virus spreading is helpful for adopting immunity policy.

  18. The Epidemic History of HIV-1 CRF07_BC in Hetian Prefecture and the Role of It on HIV Spreading in China.

    Science.gov (United States)

    Wu, Jianjun; Guo, Hongxiong; Zhang, Jing; Liu, Xiaoming; Ayoupu, Aideaierli; Shen, Yuelan; Miao, Lifeng; Tang, Jihai; Lei, Yanhua; Su, Bin

    2017-04-01

    CRF07_BC is one of the most prevalent HIV-1 strains in China, and Xinjiang Uygur Autonomous Region has ever been considered to be a second epidemic center after Yunnan Province in previous studies. Here we use HIV-1 pol gene sequences identified from Hetian Prefecture located in Xinjiang Autonomous Region to reconstruct the epidemic history of HIV CRF07_BC strain circulating in this region. We found that CRF07_BC is the predominant HIV-1 form in Hetian Prefecture, and the estimated tMRCA analysis shows that there is no enough evidence supporting Xinjiang Autonomous Region as a second epidemic center of spreading HIV-1. It may imply that every city may be only a point among the HIV spreading network because of the frequent migration of population in the whole country nowadays.

  19. Adolescent girls and young women: key populations for HIV epidemic control.

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    Dellar, Rachael C; Dlamini, Sarah; Karim, Quarraisha Abdool

    2015-01-01

    At the epicentre of the HIV epidemic in southern Africa, adolescent girls and young women aged 15-24 contribute a disproportionate ~30% of all new infections and seroconvert 5-7 years earlier than their male peers. This age-sex disparity in HIV acquisition continues to sustain unprecedentedly high incidence rates, and preventing HIV infection in this age group is a pre-requisite for achieving an AIDS-free generation and attaining epidemic control. Adolescent girls and young women in southern Africa are uniquely vulnerable to HIV and have up to eight times more infection than their male peers. While the cause of this vulnerability has not been fully elucidated, it is compounded by structural, social and biological factors. These factors include but are not limited to: engagement in age-disparate and/or transactional relationships, few years of schooling, experience of food insecurity, experience of gender-based violence, increased genital inflammation, and amplification of effects of transmission co-factors. Despite the large and immediate HIV prevention need of adolescent girls and young women, there is a dearth of evidence-based interventions to reduce their risk. The exclusion of adolescents in biomedical research is a huge barrier. School and community-based education programmes are commonplace in many settings, yet few have been evaluated and none have demonstrated efficacy in preventing HIV infection. Promising data are emerging on prophylactic use of anti-retrovirals and conditional cash transfers for HIV prevention in these populations. There is an urgent need to meet the HIV prevention needs of adolescent girls and young women, particularly those who are unable to negotiate monogamy, condom use and/or male circumcision. Concerted efforts to expand the prevention options available to these young women in terms of the development of novel HIV-specific biomedical, structural and behavioural interventions are urgently needed for epidemic control. In the interim

  20. Interplay Between Hiv/aids Epidemics and Demographic Structures Based on Sexual Contact Networks

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    Bai, Wen-Jie; Zhou, Tao; Wang, Bing-Hong

    In this article, we propose a network spreading model for HIV epidemics, wherein each individual is represented by a node of the transmission network and the edges are the connections between individuals along which the infection may spread. The sexual activity of each individual, measured by its degree, is not homogeneous but obeys a power-law distribution. Due to the heterogeneity of activity, the infection can persistently exist at a very low prevalence, which has been observed in the real data but cannot be illuminated by previous models with homogeneous mixing hypothesis. The model displays a clear picture of hierarchical spread: In the early stage the infection is adhered to these high-risk persons, and then, diffuses toward low-risk population. Furthermore, we find that to reduce the risky behaviors is much more effective in the fight against HIV/AIDS rather than the antiretroviral drug therapies. The prediction results show that the development of epidemics can be roughly categorized into three patterns for different countries, and the pattern of a given country is mainly determined by the average sex-activity and transmission probability per sexual partner. In most cases, the effect of HIV epidemics on demographic structure is very small. However, for some extremely countries, like Botswana, the number of sex-active people can be depressed to nearly a half by AIDS.

  1. Dynamical Analysis of SIR Epidemic Models with Distributed Delay

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    Wencai Zhao

    2013-01-01

    Full Text Available SIR epidemic models with distributed delay are proposed. Firstly, the dynamical behaviors of the model without vaccination are studied. Using the Jacobian matrix, the stability of the equilibrium points of the system without vaccination is analyzed. The basic reproduction number R is got. In order to study the important role of vaccination to prevent diseases, the model with distributed delay under impulsive vaccination is formulated. And the sufficient conditions of globally asymptotic stability of “infection-free” periodic solution and the permanence of the model are obtained by using Floquet’s theorem, small-amplitude perturbation skills, and comparison theorem. Lastly, numerical simulation is presented to illustrate our main conclusions that vaccination has significant effects on the dynamical behaviors of the model. The results can provide effective tactic basis for the practical infectious disease prevention.

  2. The HIV epidemic and sexual and reproductive health policy integration: views of South African policymakers.

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    Cooper, Diane; Mantell, Joanne E; Moodley, Jennifer; Mall, Sumaya

    2015-03-04

    Integration of sexual and reproductive health (SRH) and HIV policies and services delivered by the same provider is prioritised worldwide, especially in sub-Saharan Africa where HIV prevalence is highest. South Africa has the largest antiretroviral treatment (ART) programme in the world, with an estimated 2.7 million people on ART, elevating South Africa's prominence as a global leader in HIV treatment. In 2011, the Southern African HIV Clinicians Society published safer conception guidelines for people living with HIV (PLWH) and in 2013, the South African government published contraceptive guidelines highlighting the importance of SRH and fertility planning services for people living with HIV. Addressing unintended pregnancies, safer conception and maternal health issues is crucial for improving PLWH's SRH and combatting the global HIV epidemic. This paper explores South African policymakers' perspectives on public sector SRH-HIV policy integration, with a special focus on the need for national and regional policies on safer conception for PLWH and contraceptive guidelines implementation. It draws on 42 in-depth interviews with national, provincial and civil society policymakers conducted between 2008-2009 and 2011-2012, as the number of people on ART escalated. Interviews focused on three key domains: opinions on PLWH's childbearing; the status of SRH-HIV integration policies and services; and thoughts and suggestions on SRH-HIV integration within the restructuring of South African primary care services. Data were coded and analysed according to themes. Participants supported SRH-HIV integrated policy and services. However, integration challenges identified included a lack of policy and guidelines, inadequately trained providers, vertical programming, provider work overload, and a weak health system. Participants acknowledged that SRH-HIV integration policies, particularly for safer conception, contraception and cervical cancer, had been neglected. Policymakers

  3. Shift in HIV/AIDS Epidemic in Southeastern China: A Longitudinal Study from 1987 to 2015.

    Science.gov (United States)

    Yan, Yansheng; Wu, Shouli; Chen, Liang; Yan, Pingping; Qiu, Yuefeng; Xie, Meirong; Wang, Zhenghua; Lin, Xun

    2016-08-06

    study period, and CRF01-AE and CRF07-BC intersubtype recombinant forms were predominant; however, a declining trend in the proportion of HIV-1 CRF01-AE recombinant virus and a significant rise in the proportion of HIV-1 CRF07-BC recombinant virus were observed. Over 90% HIV inhibition was found in all cases receiving antiretroviral therapy during the period from 2011 to 2015, indicating a low prevalence of HIV drug resistance. An increasing trend is still observed in the HIV/AIDS epidemics in Fujian Province, southeastern China. However, the epidemiological pattern of HIV/AIDS has recently changed in the province, and effective control interventions targeting the shift in the epidemiological features of HIV/AIDS should therefore be implemented to control the spread of the epidemic.

  4. When Statistical Literacy Really Matters: Understanding Published Information about the HIV/AIDS Epidemic in South Africa

    Science.gov (United States)

    Hobden, Sally

    2014-01-01

    Information on the HIV/AIDS epidemic in Southern Africa is often interpreted through a veil of secrecy and shame and, I argue, with flawed understanding of basic statistics. This research determined the levels of statistical literacy evident in 316 future Mathematical Literacy teachers' explanations of the median in the context of HIV/AIDS…

  5. Testing the hypothesis that treatment can eliminate HIV: a nationwide, population-based study of the Danish HIV epidemic in men who have sex with men.

    Science.gov (United States)

    Okano, Justin T; Robbins, Danielle; Palk, Laurence; Gerstoft, Jan; Obel, Niels; Blower, Sally

    2016-07-01

    Worldwide, approximately 35 million individuals are infected with HIV; about 25 million of these live in sub-Saharan Africa. WHO proposes using treatment as prevention (TasP) to eliminate HIV. Treatment suppresses viral load, decreasing the probability an individual transmits HIV. The elimination threshold is one new HIV infection per 1000 individuals. Here, we test the hypothesis that TasP can substantially reduce epidemics and eliminate HIV. We estimate the impact of TasP, between 1996 and 2013, on the Danish HIV epidemic in men who have sex with men (MSM), an epidemic UNAIDS has identified as a priority for elimination. We use a CD4-staged Bayesian back-calculation approach to estimate incidence, and the hidden epidemic (the number of HIV-infected undiagnosed MSM). To develop the back-calculation model, we use data from an ongoing nationwide population-based study: the Danish HIV Cohort Study. Incidence, and the hidden epidemic, decreased substantially after treatment was introduced in 1996. By 2013, incidence was close to the elimination threshold: 1·4 (median, 95% Bayesian credible interval [BCI] 0·4-2·1) new HIV infections per 1000 MSM and there were only 617 (264-858) undiagnosed MSM. Decreasing incidence and increasing treatment coverage were highly correlated; a treatment threshold effect was apparent. Our study is the first to show that TasP can substantially reduce a country's HIV epidemic, and bring it close to elimination. However, we have shown the effectiveness of TasP under optimal conditions: very high treatment coverage, and exceptionally high (98%) viral suppression rate. Unless these extremely challenging conditions can be met in sub-Saharan Africa, the WHO's global elimination strategy is unlikely to succeed. National Institute of Allergy and Infectious Diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Effectiveness and cost effectiveness of expanding harm reduction and antiretroviral therapy in a mixed HIV epidemic: a modeling analysis for Ukraine.

    Directory of Open Access Journals (Sweden)

    Sabina S Alistar

    2011-03-01

    Full Text Available Injection drug use (IDU and heterosexual virus transmission both contribute to the growing mixed HIV epidemics in Eastern Europe and Central Asia. In Ukraine-chosen in this study as a representative country-IDU-related risk behaviors cause half of new infections, but few injection drug users (IDUs receive methadone substitution therapy. Only 10% of eligible individuals receive antiretroviral therapy (ART. The appropriate resource allocation between these programs has not been studied. We estimated the effectiveness and cost-effectiveness of strategies for expanding methadone substitution therapy programs and ART in mixed HIV epidemics, using Ukraine as a case study.We developed a dynamic compartmental model of the HIV epidemic in a population of non-IDUs, IDUs using opiates, and IDUs on methadone substitution therapy, stratified by HIV status, and populated it with data from the Ukraine. We considered interventions expanding methadone substitution therapy, increasing access to ART, or both. We measured health care costs, quality-adjusted life years (QALYs, HIV prevalence, infections averted, and incremental cost-effectiveness. Without incremental interventions, HIV prevalence reached 67.2% (IDUs and 0.88% (non-IDUs after 20 years. Offering methadone substitution therapy to 25% of IDUs reduced prevalence most effectively (to 53.1% IDUs, 0.80% non-IDUs, and was most cost-effective, averting 4,700 infections and adding 76,000 QALYs compared with no intervention at US$530/QALY gained. Expanding both ART (80% coverage of those eligible for ART according to WHO criteria and methadone substitution therapy (25% coverage was the next most cost-effective strategy, adding 105,000 QALYs at US$1,120/QALY gained versus the methadone substitution therapy-only strategy and averting 8,300 infections versus no intervention. Expanding only ART (80% coverage added 38,000 QALYs at US$2,240/QALY gained versus the methadone substitution therapy-only strategy, and

  7. Research Notes ~ Combating HIV/AIDS Epidemic in Nigeria: Responses from National Open University of Nigeria (NOUN

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    Terhemba Nom Ambe-Uva

    2007-11-01

    Full Text Available Universities have come under serious attack because of their lackluster response to HIV/AIDS. This article examines the response of National Open University of Nigeria (NOUN and its strategic responses in combating HIV/AIDS epidemic. This is achieved by examining NOUN’s basic structures that position the University to respond to the epidemic; and second, by assessing HIV/AIDS strategies and policy framework the University has put in place. An interpretative epistemological stance was used for this study, and a qualitative research involving focus group discussion (FGD and analysis of secondary data was carried out. Results showed that NOUN has identified the impact the epidemic has on the university, although it has yet to institutionalize an HIV/AIDS policy. NOUN’s Draft Service Charter, however, has identified the fight against HIV/AIDS as a core mandate of the University, and the introduction of HIV/AIDS certification programs can be viewed as proactive policies in response to the epidemic. Results of this study are discussed in terms of their relevance to future research and the impact such policy frameworks may have on combating the epidemic, both within the University and the wider community.

  8. [Facing the HIV/AIDS epidemic in Mexico: the response of the health sector].

    Science.gov (United States)

    Gutiérrez, Juan Pablo; López-Zaragoza, José Luis; Valencia-Mendoza, Atanacio; Pesqueira, Eduardo; Ponce-de-León, Samuel; Bertozzi, Stefano M

    2004-01-01

    To analyze the challenges and accomplishments of the Mexican health system as it faced the HIV/AIDS epidemic over the 20 years since discovery of the virus. A review of the relevant literature was done. The topics revised were: HIV/AIDS epidemiology, the early response of the health system and civil society, prevention and risk behaviors, care and treatment, and financing and resources allocation. In Mexico a rapid initial public response surely contributed to containing any early spread of the epidemic to select populations; whether that spread will continue to be contained is an open question. Sexual risk practices remain high not only among traditional risk populations but also among youth. Even though the epidemic remains concentrated in Mexico, principally among MSM and IDU, only 13% of public HIV prevention funds are directed to key populations at especially high risk of becoming infected or infecting others. In recent years antiretroviral coverage has increased rapidly with funding increasing from 30 to 367 million pesos from 2001 to 2003 and coverage now approaching 100%. Of all health spending on HIV/AIDS in the public sector, 82.4% is spent by the social security institutes and 17.6% by the Ministry of Health. The former provides medical care to about half of PLHA while the latter, in addition to caring for the other half, supports the large majority of prevention expenses. One of the challenges faced by the health system which has largely achieved universal antiretroviral coverage is how to provide quality care with appropriate monitoring, promotion of adherence and recognition and treatment of resistance and adverse effects--without dramatically increasing costs.

  9. Threshold-based epidemic dynamics in systems with memory

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    Bodych, Marcin; Ganguly, Niloy; Krueger, Tyll; Mukherjee, Animesh; Siegmund-Schultze, Rainer; Sikdar, Sandipan

    2016-11-01

    In this article we analyze an epidemic dynamics model (SI) where we assume that there are k susceptible states, that is a node would require multiple (k) contacts before it gets infected. In specific, we provide a theoretical framework for studying diffusion rate in complete graphs and d-regular trees with extensions to dense random graphs. We observe that irrespective of the topology, the diffusion process could be divided into two distinct phases: i) the initial phase, where the diffusion process is slow, followed by ii) the residual phase where the diffusion rate increases manifold. In fact, the initial phase acts as an indicator for the total diffusion time in dense graphs. The most remarkable lesson from this investigation is that such a diffusion process could be controlled and even contained if acted upon within its initial phase.

  10. Women's rights and women's health during HIV/AIDS epidemics: the experience of women in sub-Saharan Africa.

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    Dugassa, Begna F

    2009-08-01

    Twenty-five years have passed since HIV/AIDS was recognized as a major public health problem. Although billions of dollars are spent in research and development, we still have no medical cure or vaccination. In the early days of the epidemic, public health slogans suggested that HIV/AIDS does not discriminate. Now it is becoming clear that HIV/AIDS spreads most rapidly among poor, marginalized, women, colonized, and disempowered groups of people more than others. The HIV/AIDS epidemic is exacerbated by the social, economic, political, and cultural conditions of societies such as gender, racial, class, and other forms of inequalities. Sub-Saharan African countries are severely hit by HIV/AIDS. For these countries the pandemic of HIV/AIDS demands the need to travel extra miles. My objective in this article is to promote the need to go beyond the biomedical model of "technical fixes" and the traditional public health education tools, and come up with innovative ideas and strategic thinking to contain the epidemic. In this article, I argue that containing the HIV/AIDS epidemic and improving family and community health requires giving appropriate attention to the social illnesses that are responsible for exacerbating biological disorders.

  11. Increasing rates of obesity among HIV-infected persons during the HIV epidemic.

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    Nancy Crum-Cianflone

    2010-04-01

    Full Text Available The prevalence and factors associated with overweight/obesity among human immunodeficiency virus (HIV-infected persons are unknown.We evaluated prospective data from a U.S. Military HIV Natural History Study (1985-2004 consisting of early diagnosed patients. Statistics included multivariate linear regression and longitudinal linear mixed effects models.Of 1682 patients, 2% were underweight, 37% were overweight, and 9% were obese at HIV diagnosis. Multivariate predictors of a higher body mass index (BMI at diagnosis included more recent year of HIV diagnosis, older age, African American race, and earlier HIV stage (all p<0.05. The majority of patients (62% gained weight during HIV infection. Multivariate factors associated with a greater increase in BMI during HIV infection included more recent year of diagnosis, lower BMI at diagnosis, higher CD4 count, lower HIV RNA level, lack of AIDS diagnosis, and longer HIV duration (all p<0.05. Nucleoside agents were associated with less weight gain; other drug classes had no significant impact on weight change in the HAART era.HIV-infected patients are increasingly overweight/obese at diagnosis and during HIV infection. Weight gain appears to reflect improved health status and mirror trends in the general population. Weight management programs may be important components of HIV care.

  12. Increasing survival time decreases the cost-effectiveness of using "test & treat'' to eliminate HIV epidemics.

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    Wagner, Bradley G; Coburn, Brian J; Blower, Sally

    2013-01-01

    Treating HIV-infected individuals reduces their viral load, consequently increasing their survival time and decreasing their infectivity. It has been proposed that universal testing and treatment (i.e., universal "test & treat'') could lead to HIV elimination and would be extremely cost-effective. It is now being debated whether to use a universal "test & treat'' approach in the "real-world'' as a prevention strategy to control HIV epidemics. However current modeling predictions of the impact, and cost-effectiveness, of universal `"est & treat'' strategies are based on an unrealistically short survival time for treated individuals. Here we use mathematical modeling and a longer, more realistic, survival time. We model the potential impact of a universal "test & treat'' strategy in South Africa. Our results show that increasing the length of the survival time on treatment, although beneficial to individuals, reduces the probability of eliminating HIV and decreases the cost-effectiveness of using universal "test & treat'' strategies. Therefore our results show that individual-level benefits and public health benefits will conflict when using "test &treat'' strategies to reduce HIV transmission.

  13. A Decade of Monitoring HIV Epidemics in Nigeria: Positioning for Post-2015 Agenda.

    Science.gov (United States)

    Akinwande, Oluyemisi; Bashorun, Adebobola; Azeez, Aderemi; Agbo, Francis; Dakum, Patrick; Abimiku, Alashle; Bilali, Camara; Idoko, John; Ogungbemi, Kayode

    2017-07-01

    Nigeria accounts for 9% of the global HIV burden and is a signatory to Millennium Development Goals as well as the post-2015 Sustainable Development Goals. This paper reviews maturation of her HIV M&E system and preparedness for monitoring of the post-2015 agenda. Using the UNAIDS criteria for assessing a functional M&E system, a mixed-methods approach of desk review and expert consultations, was employed. Following adoption of a multi-sectoral M&E system, Nigeria experienced improved HIV coordination at the National and State levels, capacity building for epidemic appraisals, spectrum estimation and routine data quality assessments. National data and systems audit processes were instituted which informed harmonization of tools and indicators. The M&E achievements of the HIV response enhanced performance of the National Health Management Information System (NHMIS) using DHIS2 platform following its re-introduction by the Federal Ministry of Health, and also enabled decentralization of data management to the periphery. A decade of implementing National HIV M&E framework in Nigeria and the recent adoption of the DHIS2 provides a strong base for monitoring the Post 2015 agenda. There is however a need to strengthen inter-sectoral data linkages and reduce the rising burden of data collection at the global level.

  14. Legislative epidemics: the role of model law in the transnational trend to criminalise HIV transmission.

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    Grace, Daniel

    2013-12-01

    HIV-related state laws are being created transnationally though the use of omnibus model laws. In 2004, the US Agency for International Development (USAID) funded the creation of one such guidance text known as the USAID/Action for West Africa Region Model Law, or N'Djamena Model Law, which led to the rapid spread of HIV/AIDS laws, including the criminalisation of HIV transmission, across much of West and Central Africa (2005-2010). In this article, I explicate how an epidemic of highly problematic legislation spread across the region as a result of a text-mediated work process enabled through model laws. I theorise the textual genre of model laws arguing that these texts are best understood as 'preoperative documents' which, when activated, can lead to swift legislative reform in and beyond the field of HIV/AIDS governance. The legislative process being investigated was made visible through participant observation, archival research, textual analysis and informant interviews with national and international stakeholders (n=32). This involved ethnographic research in Canada, the USA, Switzerland, Austria, South Africa and Senegal (2010-2011). The untold policy processes and narratives explored in this article make evident how the work of contesting problematic HIV/AIDS model laws and newly drafted state laws involves both creating new texts and contesting the legitimacy and efficacy of others.

  15. Orphans of the HIV epidemic: the challenges from toddlerhood to adolescence and beyond.

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    Lala, Mamatha M

    2014-01-01

    This presentation focuses on the challenges and practical issues faced each day by orphans of the HIV epidemic and the holistic care that can be provided, as they continue to grow from toddlerhood to adolescence and beyond. An HIV Research Trust Scholarship enabled me to spend quality time in a sub-Saharan African province worst hit by the HIV epidemic and to interact with local experts and learn from mutual clinical experience. It was an immensely useful exercise as the clinical spectra of the diseases are very similar to ours and they have ongoing active research programs very relevant to our setting. India is arguably home to the largest number of orphans of the HIV epidemic. The responsibility of caring for orphaned children overwhelms and pushes many extended families beyond their ability to cope. Many countries are experiencing large increases in the number of families headed by women and grandparents, or even young children. These households are often unable to meet basic needs, and so the number of children living on the streets is rising. Orphaned children are disadvantaged in many devastating ways. In addition to the trauma of witnessing the sickness and death of one or both parents and perhaps siblings, they lack the necessary parental guidance through crucial life-stages of identity formation and transition into adulthood. They are more likely to suffer damage to their cognitive and emotional development and be subjected to; exploitation in terms of labour, social exclusion, extreme economic uncertainty, physical and sexual abuse, illiteracy, malnutrition and illness. Education remains a distant dream. With stigma and discrimination, they lack legal protection, lose inheritance rights, access to essential services available to other community members and professional help from doctors, teachers and lawyers. The implications for these unfortunate children are extraordinarily grave but governments, international agencies, non-governmental organizations

  16. Impact of long-term civil disorders and wars on the trajectory of HIV epidemics in sub-Saharan Africa.

    Science.gov (United States)

    Gisselquist, David

    2004-08-01

    From the mid-1970s, seven countries in sub-Saharan Africa have experienced civil disorders and wars lasting for at least 10 years. In two-- Sierra Leone during 1991-2002, and Somalia from 1988 and continuing--adult HIV prevalence remained below 1%. In the Democratic Republic of the Congo, HIV prevalence appears to have stabilised during post-1991 civil disorder and war. Limited information from Angola (civil war 1975 -2002) and Liberia (civil disorder and war from 1989 and continuing) suggests low HIV prevalence. Mozambique's HIV prevalence was near 1% after its 1975 - 1992 civil war, but increased dramatically in the first post-war decade. Across African countries with long-term wars, HIV seems to have spread more slowly than in most neighbouring countries at peace. This evidence contributes to the ongoing debate about the factors that explain differential epidemic trajectories, a debate which is crucial to the design of HIV prevention programmes. One possible explanation for slow epidemic growth in wartime is that unsterile health care accounts for an important proportion of HIV transmission during peacetime, but much less when wars disrupt health services. However, other explanations are also possible. The roles of sex and blood exposures in HIV epidemics in war and peace await empirical determination.

  17. Effectiveness and cost effectiveness of oral pre-exposure prophylaxis in a portfolio of prevention programs for injection drug users in mixed HIV epidemics.

    Directory of Open Access Journals (Sweden)

    Sabina S Alistar

    Full Text Available BACKGROUND: Pre-exposure prophylaxis with oral antiretroviral treatment (oral PrEP for HIV-uninfected injection drug users (IDUs is potentially useful in controlling HIV epidemics with a significant injection drug use component. We estimated the effectiveness and cost effectiveness of strategies for using oral PrEP in various combinations with methadone maintenance treatment (MMT and antiretroviral treatment (ART in Ukraine, a representative case for mixed HIV epidemics. METHODS AND FINDINGS: We developed a dynamic compartmental model of the HIV epidemic in a population of non-IDUs, IDUs who inject opiates, and IDUs in MMT, adding an oral PrEP program (tenofovir/emtricitabine, 49% susceptibility reduction for uninfected IDUs. We analyzed intervention portfolios consisting of oral PrEP (25% or 50% of uninfected IDUs, MMT (25% of IDUs, and ART (80% of all eligible patients. We measured health care costs, quality-adjusted life years (QALYs, HIV prevalence, HIV infections averted, and incremental cost effectiveness. A combination of PrEP for 50% of IDUs and MMT lowered HIV prevalence the most in both IDUs and the general population. ART combined with MMT and PrEP (50% access averted the most infections (14,267. For a PrEP cost of $950, the most cost-effective strategy was MMT, at $520/QALY gained versus no intervention. The next most cost-effective strategy consisted of MMT and ART, costing $1,000/QALY gained compared to MMT alone. Further adding PrEP (25% access was also cost effective by World Health Organization standards, at $1,700/QALY gained. PrEP alone became as cost effective as MMT at a cost of $650, and cost saving at $370 or less. CONCLUSIONS: Oral PrEP for IDUs can be part of an effective and cost-effective strategy to control HIV in regions where injection drug use is a significant driver of the epidemic. Where budgets are limited, focusing on MMT and ART access should be the priority, unless PrEP has low cost.

  18. Effectiveness and Cost Effectiveness of Oral Pre-Exposure Prophylaxis in a Portfolio of Prevention Programs for Injection Drug Users in Mixed HIV Epidemics

    Science.gov (United States)

    Alistar, Sabina S.; Owens, Douglas K.; Brandeau, Margaret L.

    2014-01-01

    Background Pre-exposure prophylaxis with oral antiretroviral treatment (oral PrEP) for HIV-uninfected injection drug users (IDUs) is potentially useful in controlling HIV epidemics with a significant injection drug use component. We estimated the effectiveness and cost effectiveness of strategies for using oral PrEP in various combinations with methadone maintenance treatment (MMT) and antiretroviral treatment (ART) in Ukraine, a representative case for mixed HIV epidemics. Methods and Findings We developed a dynamic compartmental model of the HIV epidemic in a population of non-IDUs, IDUs who inject opiates, and IDUs in MMT, adding an oral PrEP program (tenofovir/emtricitabine, 49% susceptibility reduction) for uninfected IDUs. We analyzed intervention portfolios consisting of oral PrEP (25% or 50% of uninfected IDUs), MMT (25% of IDUs), and ART (80% of all eligible patients). We measured health care costs, quality-adjusted life years (QALYs), HIV prevalence, HIV infections averted, and incremental cost effectiveness. A combination of PrEP for 50% of IDUs and MMT lowered HIV prevalence the most in both IDUs and the general population. ART combined with MMT and PrEP (50% access) averted the most infections (14,267). For a PrEP cost of $950, the most cost-effective strategy was MMT, at $520/QALY gained versus no intervention. The next most cost-effective strategy consisted of MMT and ART, costing $1,000/QALY gained compared to MMT alone. Further adding PrEP (25% access) was also cost effective by World Health Organization standards, at $1,700/QALY gained. PrEP alone became as cost effective as MMT at a cost of $650, and cost saving at $370 or less. Conclusions Oral PrEP for IDUs can be part of an effective and cost-effective strategy to control HIV in regions where injection drug use is a significant driver of the epidemic. Where budgets are limited, focusing on MMT and ART access should be the priority, unless PrEP has low cost. PMID:24489747

  19. A statistical network analysis of the HIV/AIDS epidemics in Cuba

    OpenAIRE

    Clémençon, Stéphan; De Arazoza, Hector; Rossi, Fabrice; Tran, Viet Chi

    2014-01-01

    International audience; The Cuban contact-tracing detection system set up in 1986 allowed the reconstruction and analysis of the sexual network underlying the epidemic (5,389 vertices and 4,073 edges, giant component of 2,386 nodes and 3,168 edges), shedding light onto the spread of HIV and the role of contact-tracing. Clustering based on modularity optimization provides a better visualization and understanding of the network, in combination with the study of covariates. The graph has a globa...

  20. Male Circumcision and the Epidemic Emergence of HIV-2 in West Africa

    Science.gov (United States)

    Hewlett, Barry Stephen; Camacho, Ricardo Jorge

    2016-01-01

    Background Epidemic HIV-2 (groups A and B) emerged in humans circa 1930–40. Its closest ancestors are SIVsmm infecting sooty mangabeys from southwestern Côte d'Ivoire. The earliest large-scale serological surveys of HIV-2 in West Africa (1985–91) show a patchy spread. Côte d'Ivoire and Guinea-Bissau had the highest prevalence rates by then, and phylogeographical analysis suggests they were the earliest epicenters. Wars and parenteral transmission have been hypothesized to have promoted HIV-2 spread. Male circumcision (MC) is known to correlate negatively with HIV-1 prevalence in Africa, but studies examining this issue for HIV-2 are lacking. Methods We reviewed published HIV-2 serosurveys for 30 cities of all West African countries and obtained credible estimates of real prevalence through Bayesian estimation. We estimated past MC rates of 218 West African ethnic groups, based on ethnographic literature and fieldwork. We collected demographic tables specifying the ethnic partition in cities. Uncertainty was incorporated by defining plausible ranges of parameters (e.g. timing of introduction, proportion circumcised). We generated 1,000 sets of past MC rates per city using Latin Hypercube Sampling with different parameter combinations, and explored the correlation between HIV-2 prevalence and estimated MC rate (both logit-transformed) in the 1,000 replicates. Results and Conclusions Our survey reveals that, in the early 20th century, MC was far less common and geographically more variable than nowadays. HIV-2 prevalence in 1985–91 and MC rates in 1950 were negatively correlated (Spearman rho = -0.546, IQR: -0.553–-0.546, p≤0.0021). Guinea-Bissau and Côte d'Ivoire cities had markedly lower MC rates. In addition, MC was uncommon in rural southwestern Côte d'Ivoire in 1930.The differential HIV-2 spread in West Africa correlates with different historical MC rates. We suggest HIV-2 only formed early substantial foci in cities with substantial uncircumcised

  1. Impact and Cost-Effectiveness of Point-Of-Care CD4 Testing on the HIV Epidemic in South Africa.

    Directory of Open Access Journals (Sweden)

    Alastair Heffernan

    Full Text Available Rapid diagnostic tools have been shown to improve linkage of patients to care. In the context of infectious diseases, assessing the impact and cost-effectiveness of such tools at the population level, accounting for both direct and indirect effects, is key to informing adoption of these tools. Point-of-care (POC CD4 testing has been shown to be highly effective in increasing the proportion of HIV positive patients who initiate ART. We assess the impact and cost-effectiveness of introducing POC CD4 testing at the population level in South Africa in a range of care contexts, using a dynamic compartmental model of HIV transmission, calibrated to the South African HIV epidemic. We performed a meta-analysis to quantify the differences between POC and laboratory CD4 testing on the proportion linking to care following CD4 testing. Cumulative infections averted and incremental cost-effectiveness ratios (ICERs were estimated over one and three years. We estimated that POC CD4 testing introduced in the current South African care context can prevent 1.7% (95% CI: 0.4% - 4.3% of new HIV infections over 1 year. In that context, POC CD4 testing was cost-effective 99.8% of the time after 1 year with a median estimated ICER of US$4,468/DALY averted. In healthcare contexts with expanded HIV testing and improved retention in care, POC CD4 testing only became cost-effective after 3 years. The results were similar when, in addition, ART was offered irrespective of CD4 count, and CD4 testing was used for clinical assessment. Our findings suggest that even if ART is expanded to all HIV positive individuals and HIV testing efforts are increased in the near future, POC CD4 testing is a cost-effective tool, even within a short time horizon. Our study also illustrates the importance of evaluating the potential impact of such diagnostic technologies at the population level, so that indirect benefits and costs can be incorporated into estimations of cost-effectiveness.

  2. Religious and cultural traits in HIV/AIDS epidemics in sub-Saharan Africa.

    Science.gov (United States)

    Velayati, Ali-Akbar; Bakayev, Valerii; Bahadori, Moslem; Tabatabaei, Seyed-Javad; Alaei, Arash; Farahbood, Amir; Masjedi, Mohammad-Reza

    2007-10-01

    The pandemic of HIV/AIDS in sub-Saharan Africa and the rise of epidemics in Asia to the previously unforeseen level are likely to have global social, economic, and political impacts. In this emergency, it is vital to reappraise the weight of powerful religious and cultural factors in spreading the disease. The role of Islam in shaping values, norms, and public policies in North African states is to be appreciated for the lowest HIV prevalence in their populations. Yet, the place of religion in prevention of the disease diffusion is not fully understood nor worldwide acknowledged by the primary decision makers. Another topic, which has received little attention to date, despite the abundance of literature concerning the unfortunate Africa's anti-AIDS campaign, is an issue of colonial past. To better comprehend the share of both traits in diverse spread of HIV in sub-Saharan Africa, we studied the correlation between Muslim and Christian proportions in the state's population and HIV rate. By this method, Muslim percentage came out as a potential predictor of HIV prevalence in a given state. In another approach, most subcontinental countries were clustered by colocalization and similarity in their leading religion, colonial past, and HIV seroprevalence starting from barely noticeable (0.6 - 1.2%, for Mauritania, Senegal, Somalia, and Niger) and low levels (1.9 - 4.8%, for Mali, Eritrea, Djibouti, Guinea, Guinea-Bissau, Burkina-Faso, and Chad) for Muslim populated past possessions of France and Italy, in the northern part of the subcontinent. Former territories of France, Belgium, Portugal, and the UK formed two other groups of the countries nearing the equator with Catholic prevailing (Democratic Republic of Congo, Republic of Congo, Rwanda, Gabon, and Burundi) or mixed populations comprising Christian, Muslim, and indigenous believers (Benin, Ghana, Uganda, Togo, Angola, Nigeria, Liberia, Kenya, Cameroon, Côte d'Ivoire, and Sierra-Leone), which covered the HIV

  3. Rural black women's agency within intimate partnerships amid the South African HIV epidemic.

    Science.gov (United States)

    Thege, Britta

    2009-12-01

    In a particular way, the HIV pandemic exposes the prevailing gender relations and the definitions of male and female gender roles, both in intimate relationships and in the wider society. The HIV pandemic reveals the contradictions between women's legal rights and the persistence of women's cultural and sexual subordination. It reflects the impact of poverty, gender roles, culture and religion. Although HIV and AIDS cuts across class, South African rural black women's infection risk seems particularly high since they suffer notably from subordination and socio-economic hardships. Negotiating safer sex in marriage or intimate partnerships is very difficult for them in view of the traditional spaces in which they find themselves, where patriarchal structures are pervasive. Based on data obtained from a case study, this paper examines socio-cultural constraints to rural women's sexual agency in a patriarchal social order. These rules are based on a patriarchal code of respect, which is still pervasive in many aspects of the community under investigation. In terms of gender relations, the patriarchal code of respect is founded on an assumed 'naturalisation' of the two genders and the natural superiority of the male over the female. In terms of sexuality it is translated into male sex-right. The fear of HIV infection is omnipresent and results in unmarried women engaging in the negotiation of their wants and needs. Owing to the patriarchal code of respect, married women are perceived as having no choice in negotiating safer sex and are forced to put their lives at risk in contracting HIV. Unmarried women have greater although not endless choices in this regard. Although the study participants unexpectedly displayed a rather negative perception of other women, in order to strengthen women in their proximal environment the HIV epidemic may be seen as a vehicle for building solidarity among women in the community.

  4. Trends in three decades of HIV/AIDS epidemic in Thailand by nonparametric backcalculation method.

    Science.gov (United States)

    Punyacharoensin, Narat; Viwatwongkasem, Chukiat

    2009-06-01

    To reconstruct the past HIV incidence and prevalence in Thailand from 1980 to 2008 and predict the country's AIDS incidence from 2009 to 2011. Nonparametric backcalculation was adopted utilizing 100 quarterly observed new AIDS counts excluding pediatric cases. The accuracy of data was enhanced through a series of data adjustments using the weight method to account for several surveillance reporting issues. The mixture of time-dependent distributions allowed the effects of age at seroconversion and antiretroviral therapy to be incorporated simultaneously. Sensitivity analyses were conducted to assess model variations that were subject to major uncertainties. Future AIDS incidence was projected for various predetermined HIV incidence patterns. HIV incidence in Thailand reached its peak in 1992 with approximately 115,000 cases. A steep decline thereafter discontinued in 1997 and was followed by another strike of 42,000 cases in 1999. The second surge, which happened concurrently with the major economic crisis, brought on 60,000 new infections. As of December 2008, more than 1 million individuals had been infected and around 430,000 adults were living with HIV corresponding to a prevalence rate of 1.2%. The incidence rate had become less than 0.1% since 2002. The backcalculated estimates were dominated by postulated median AIDS progression time and adjustments to surveillance data. Our analysis indicated that, thus far, the 1990s was the most severe era of HIV/AIDS epidemic in Thailand with two HIV incidence peaks. A drop in new infections led to a decrease in recent AIDS incidence, and this tendency is likely to remain unchanged until 2011, if not further.

  5. Epidemiological bridging by injection drug use drives an early HIV epidemic

    Directory of Open Access Journals (Sweden)

    Erik Volz

    2010-09-01

    Full Text Available The risk of acquiring sexually transmitted infections (STIs depends on individual behavior and the network of risky partnerships in which an individual participates. STI epidemics often spread rapidly and primarily among individuals central to transmission networks; and thus they often defy the mass-action principle since incidence is not proportional to the infectious fraction of the population. Here, we estimate the contact network structure for an Atlanta, Georgia community with heterogeneous sexual and drug-related risk behaviors and build a detailed transmission model for HIV through this population. We show that accurate estimation of epidemic incidence requires careful measurement and inclusion of diverse factors including concurrency (having multiple partners, the duration of partnerships, serosorting (preference for partners with matching disease state, and heterogeneity in the number and kinds of partners. In the focal population, we find that injection drug users (IDUs do not directly cause many secondary infections; yet they bridge the heterosexual and men-who-have-sex-with-men (MSM populations and are thereby indirectly responsible for extensive transmission. Keywords: HIV, Networks, Serosorting, Concurrency

  6. Characterizing the reproduction number of epidemics with early subexponential growth dynamics.

    Science.gov (United States)

    Chowell, Gerardo; Viboud, Cécile; Simonsen, Lone; Moghadas, Seyed M

    2016-10-01

    Early estimates of the transmission potential of emerging and re-emerging infections are increasingly used to inform public health authorities on the level of risk posed by outbreaks. Existing methods to estimate the reproduction number generally assume exponential growth in case incidence in the first few disease generations, before susceptible depletion sets in. In reality, outbreaks can display subexponential (i.e. polynomial) growth in the first few disease generations, owing to clustering in contact patterns, spatial effects, inhomogeneous mixing, reactive behaviour changes or other mechanisms. Here, we introduce the generalized growth model to characterize the early growth profile of outbreaks and estimate the effective reproduction number, with no need for explicit assumptions about the shape of epidemic growth. We demonstrate this phenomenological approach using analytical results and simulations from mechanistic models, and provide validation against a range of empirical disease datasets. Our results suggest that subexponential growth in the early phase of an epidemic is the rule rather the exception. Mechanistic simulations show that slight modifications to the classical susceptible-infectious-removed model result in subexponential growth, and in turn a rapid decline in the reproduction number within three to five disease generations. For empirical outbreaks, the generalized-growth model consistently outperforms the exponential model for a variety of directly and indirectly transmitted diseases datasets (pandemic influenza, measles, smallpox, bubonic plague, cholera, foot-and-mouth disease, HIV/AIDS and Ebola) with model estimates supporting subexponential growth dynamics. The rapid decline in effective reproduction number predicted by analytical results and observed in real and synthetic datasets within three to five disease generations contrasts with the expectation of invariant reproduction number in epidemics obeying exponential growth. The

  7. Characterizing the reproduction number of epidemics with early subexponential growth dynamics

    Science.gov (United States)

    Viboud, Cécile; Simonsen, Lone; Moghadas, Seyed M.

    2016-01-01

    Early estimates of the transmission potential of emerging and re-emerging infections are increasingly used to inform public health authorities on the level of risk posed by outbreaks. Existing methods to estimate the reproduction number generally assume exponential growth in case incidence in the first few disease generations, before susceptible depletion sets in. In reality, outbreaks can display subexponential (i.e. polynomial) growth in the first few disease generations, owing to clustering in contact patterns, spatial effects, inhomogeneous mixing, reactive behaviour changes or other mechanisms. Here, we introduce the generalized growth model to characterize the early growth profile of outbreaks and estimate the effective reproduction number, with no need for explicit assumptions about the shape of epidemic growth. We demonstrate this phenomenological approach using analytical results and simulations from mechanistic models, and provide validation against a range of empirical disease datasets. Our results suggest that subexponential growth in the early phase of an epidemic is the rule rather the exception. Mechanistic simulations show that slight modifications to the classical susceptible–infectious–removed model result in subexponential growth, and in turn a rapid decline in the reproduction number within three to five disease generations. For empirical outbreaks, the generalized-growth model consistently outperforms the exponential model for a variety of directly and indirectly transmitted diseases datasets (pandemic influenza, measles, smallpox, bubonic plague, cholera, foot-and-mouth disease, HIV/AIDS and Ebola) with model estimates supporting subexponential growth dynamics. The rapid decline in effective reproduction number predicted by analytical results and observed in real and synthetic datasets within three to five disease generations contrasts with the expectation of invariant reproduction number in epidemics obeying exponential growth. The

  8. Accelerating harm reduction interventions to confront the HIV epidemic in the Western Pacific and Asia: the role of WHO (WPRO

    Directory of Open Access Journals (Sweden)

    Yifei Hu

    2008-08-01

    Full Text Available Abstract The epidemic of HIV/AIDS linked to injecting drug usage is one of the most explosive in recent years. After a historical epicentre in Europe, South and North America, at present it is clearly the main cause of dissemination of the epidemic in Eastern Europe and some key Asian countries. Recently, 10 African countries reported the spread of HIV through people who inject drugs (PWID, breaking one of the final geographical barriers to the globalization of the epidemic of HIV among and from PWID. Several countries of the Asia and Pacific Region have HIV epidemics that are driven by injecting drug usage. Harm reduction interventions have been implemented in many countries and potential barriers to implementation are being overcome. Harm reduction is no longer a marginal approach in the Region; instead, it is the core tool for responding to the HIV/AIDS epidemic among PWID. The development of a comprehensive response in the Region has been remarkable, including scaling up of needle and syringe programmes (NSPs, methadone maintenance treatment (MMT, and care, support and treatment for PWID. This development is being followed up by strong ongoing changes in policies and legislations. The main issue now is to enhance interventions to a level that can impact the epidemic. The World Health Organization (WHO is one of the leading UN agencies promoting harm reduction. Since the establishment of the Global Programme on AIDS, WHO has been working towards an effective response to the HIV epidemic among PWID. WHO's work is organized into a number of components: establishing an evidence base; advocacy; development of normative standards, tools and guidelines; providing technical support to countries; ensuring access to essential medicines, diagnostics and commodities; and mobilizing resources. In this paper, we trace the course of development of the HIV/AIDS epidemic among and from PWID in the Western Pacific and Asia Region (WPRO as well as WHO's role

  9. Dynamical interplay between awareness and epidemic spreading in multiplex networks

    OpenAIRE

    Granell, Clara; Gomez, Sergio; Arenas, Alex

    2013-01-01

    We present the analysis of the interrelation between two processes accounting for the spreading of an epidemics, and the information awareness to prevent its infection, on top of multiplex networks. This scenario is representative of an epidemic process spreading on a network of persistent real contacts, and a cyclic information awareness process diffusing in the network of virtual social contacts between the same individuals. The topology corresponds to a multiplex network where two diffusiv...

  10. HIV epidemic and human rights among men who have sex with men in sub-Saharan Africa: Implications for HIV prevention, care, and surveillance.

    Science.gov (United States)

    Abara, Winston E; Garba, Ibrahim

    2017-04-01

    Recent research has presented evidence that men who have sex with men (MSM) bear a disproportionate burden of HIV and are at increased risk for HIV in sub-Saharan Africa (SSA). However, many countries in SSA have failed to address the needs of MSM in national HIV/AIDS programmes. Furthermore, many MSM face structural barriers to HIV prevention and care, the most significant of which include laws that criminalise male-to-male sexual contact and facilitate stigma and discrimination. This in turn increases the vulnerability of MSM to acquiring HIV and presents barriers to HIV prevention, care, and surveillance. This relationship illustrates the link between human rights, social justice, and health outcomes and presents considerable challenges to addressing the HIV epidemic among MSM in SSA. The response to the HIV epidemic in SSA requires a non-discriminatory human rights approach to all at-risk groups, including MSM. Existing international human rights treaties, to which many SSA countries are signatories, and a 'health in all policies' approach provides a strong basis to reduce structural barriers to HIV prevention, care, surveillance, and research, and to ensure that all populations in SSA, including MSM, have access to the full range of rights that help ensure equal opportunities for health and wellness.

  11. Living and dying to be counted: What we know about the epidemiology of the global adolescent HIV epidemic.

    Science.gov (United States)

    Slogrove, Amy L; Mahy, Mary; Armstrong, Alice; Davies, Mary-Ann

    2017-05-16

    With increasing survival of vertically HIV-infected children and ongoing new horizontal HIV infections, the population of adolescents (age 10-19 years) living with HIV is increasing. This review aims to describe the epidemiology of the adolescent HIV epidemic and the ability of national monitoring systems to measure outcomes in HIV-infected adolescents through the adolescent transition to adulthood. Differences in global trends between younger (age 10-14 years) and older (age 15-19 years) adolescents in key epidemic indicators are interrogated using 2016 UNAIDS estimates. National population-based survey data in the 15 highest adolescent HIV burden countries are evaluated and examples of national case-based surveillance systems described. Finally, we consider the potential impact of adolescent-specific recommendations in the 2016 WHO Consolidated Guidelines on the Use of Antiretroviral Drugs for Treating and Preventing HIV Infection. UNAIDS estimates indicate the population of adolescents living with HIV is increasing, new HIV infections in older adolescents are declining, and while AIDS-related deaths are beginning to decline in younger adolescents, they are still increasing in older adolescents. National population-based surveys provide valuable estimates of HIV prevalence in older adolescents and recent surveys include data on younger adolescents. Only a few countries have nationwide electronic case-based HIV surveillance, with the ability to provide population-level data on key HIV outcomes in the diagnosed population living with HIV. However, in the 15 highest adolescent HIV burden countries, there are no systems tracking adolescent transition to adulthood or healthcare transition. The strength of the 2016 WHO adolescent-specific recommendations on antiretroviral therapy and provision of HIV services to adolescents was hampered by the lack of evidence specific to this age group. Progress is being made in national surveillance and global monitoring systems

  12. Voices from the Frontlines: The Epidemics of HIV/AIDS and Violence among Women and Girls

    Science.gov (United States)

    TEITELMAN, ANNE M.; SELOILWE, ESTHER S.; CAMPBELL, JACQUELYN C.

    2011-01-01

    The papers in this special issue focus on the topic of violence against women. This group of scholarly works explores theoretical issues, context and health care interventions pertaining to violence in women’s lives. In conjunction with this special issue, this editorial provides a synopsis of presentations and discussions about the topic of the intersections of gender-based violence, HIV and the girl child that took place in July 2008 as part of the 17th conference of International Council of Women’s Health Issues (ICOWHI) held in Gaborone, Botswana, focusing on the Girl Child. ICOWHI, in conjunction with the University of Botswana, Centre for the Study of HIV and AIDS (CSHA) sponsored a one day preconference on “Gender-based violence and HIV Risk among Adolescent Girls.” A diverse interdisciplinary group of scholars from around the world closely examined these interconnected epidemics in a rich day long discussion. The aim of the preconference as well as the articles in this special issue is to build scholarship and inform practice of cultural and contextual factors as they pertain to violence in the lives of women and girls in order to promote their health, safety and well-being globally. PMID:19191112

  13. "The need for circumcised men" : the quest for transformed masculinities in African Christianity in the context of the HIV epidemic

    NARCIS (Netherlands)

    van Klinken, A.S.

    2011-01-01

    In sub-Saharan Africa, among others as a result of the HIV epidemic hegemonic forms of masculinity are contested and the need to change men and to transform masculinities is widely acknowledged. This thesis investigates this development in the context of African Christianity, making use of

  14. Genotypic and Functional Impact of HIV-1 Adaptation to Its Host Population during the North American Epidemic

    Science.gov (United States)

    Carlson, Jonathan M.; Chan, Benjamin; Chopera, Denis R.; Brumme, Chanson J.; Markle, Tristan J.; Martin, Eric; Shahid, Aniqa; Anmole, Gursev; Mwimanzi, Philip; Nassab, Pauline; Penney, Kali A.; Rahman, Manal A.; Milloy, M.-J.; Schechter, Martin T.; Markowitz, Martin; Carrington, Mary; Walker, Bruce D.; Wagner, Theresa; Buchbinder, Susan; Fuchs, Jonathan; Koblin, Beryl; Mayer, Kenneth H.; Harrigan, P. Richard; Brockman, Mark A.; Poon, Art F. Y.; Brumme, Zabrina L.

    2014-01-01

    HLA-restricted immune escape mutations that persist following HIV transmission could gradually spread through the viral population, thereby compromising host antiviral immunity as the epidemic progresses. To assess the extent and phenotypic impact of this phenomenon in an immunogenetically diverse population, we genotypically and functionally compared linked HLA and HIV (Gag/Nef) sequences from 358 historic (1979–1989) and 382 modern (2000–2011) specimens from four key cities in the North American epidemic (New York, Boston, San Francisco, Vancouver). Inferred HIV phylogenies were star-like, with approximately two-fold greater mean pairwise distances in modern versus historic sequences. The reconstructed epidemic ancestral (founder) HIV sequence was essentially identical to the North American subtype B consensus. Consistent with gradual diversification of a “consensus-like” founder virus, the median “background” frequencies of individual HLA-associated polymorphisms in HIV (in individuals lacking the restricting HLA[s]) were ∼2-fold higher in modern versus historic HIV sequences, though these remained notably low overall (e.g. in Gag, medians were 3.7% in the 2000s versus 2.0% in the 1980s). HIV polymorphisms exhibiting the greatest relative spread were those restricted by protective HLAs. Despite these increases, when HIV sequences were analyzed as a whole, their total average burden of polymorphisms that were “pre-adapted” to the average host HLA profile was only ∼2% greater in modern versus historic eras. Furthermore, HLA-associated polymorphisms identified in historic HIV sequences were consistent with those detectable today, with none identified that could explain the few HIV codons where the inferred epidemic ancestor differed from the modern consensus. Results are therefore consistent with slow HIV adaptation to HLA, but at a rate unlikely to yield imminent negative implications for cellular immunity, at least in North America

  15. Ending the HIV/AIDS epidemic in low- and middle-income countries by 2030: is it possible? [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Anthony D. Harries

    2016-09-01

    Full Text Available The international community has committed to ending the epidemics of HIV/AIDS, tuberculosis, malaria, and neglected tropical infections by 2030, and this bold stance deserves universal support. In this paper, we discuss whether this ambitious goal is achievable for HIV/AIDS and what is needed to further accelerate progress. The joint United Nations Program on HIV/AIDS (UNAIDS 90-90-90 targets and the related strategy are built upon currently available health technologies that can diagnose HIV infection and suppress viral replication in all people with HIV. Nonetheless, there is much work to be done in ensuring equitable access to these HIV services for key populations and those who remain outside the rims of the traditional health services. Identifying a cure and a preventive vaccine would further help accelerate progress in ending the epidemic. Other disease control programmes could learn from the response to the HIV/AIDS epidemic.

  16. Modified social ecological model: a tool to guide the assessment of the risks and risk contexts of HIV epidemics.

    Science.gov (United States)

    Baral, Stefan; Logie, Carmen H; Grosso, Ashley; Wirtz, Andrea L; Beyrer, Chris

    2013-05-17

    Social and structural factors are now well accepted as determinants of HIV vulnerabilities. These factors are representative of social, economic, organizational and political inequities. Associated with an improved understanding of multiple levels of HIV risk has been the recognition of the need to implement multi-level HIV prevention strategies. Prevention sciences research and programming aiming to decrease HIV incidence requires epidemiologic studies to collect data on multiple levels of risk to inform combination HIV prevention packages. Proximal individual-level risks, such as sharing injection devices and unprotected penile-vaginal or penile-anal sex, are necessary in mediating HIV acquisition and transmission. However, higher order social and structural-level risks can facilitate or reduce HIV transmission on population levels. Data characterizing these risks is often far more actionable than characterizing individual-level risks. We propose a modified social ecological model (MSEM) to help visualize multi-level domains of HIV infection risks and guide the development of epidemiologic HIV studies. Such a model may inform research in epidemiology and prevention sciences, particularly for key populations including men who have sex with men (MSM), people who inject drugs (PID), and sex workers. The MSEM builds on existing frameworks by examining multi-level risk contexts for HIV infection and situating individual HIV infection risks within wider network, community, and public policy contexts as well as epidemic stage. The utility of the MSEM is demonstrated with case studies of HIV risk among PID and MSM. The MSEM is a flexible model for guiding epidemiologic studies among key populations at risk for HIV in diverse sociocultural contexts. Successful HIV prevention strategies for key populations require effective integration of evidence-based biomedical, behavioral, and structural interventions. While the focus of epidemiologic studies has traditionally been on

  17. Heterosexual male and female disparities in HIV infection at the end of an epidemic: HIV infection among persons who inject drugs in New York City, 2001-2005 and 2011-2015.

    Science.gov (United States)

    Des Jarlais, Don C; McKnight, Courtney; Feelemyer, Jonathan; Arasteh, Kamyar; Tross, Susan; Campbell, Aimee N C; Cooper, Hannah L F; Perlman, David C

    2018-04-01

    We examined whether sex disparities (heterosexual male:female) in HIV infection continue to persist at the "end of the HIV epidemic" among persons who inject drugs (PWID) in New York City (NYC). An "end of the epidemic" was operationally defined as 1) prevalence of untreated HIV infection <5%, and 2) estimated HIV incidence <0.5/100 person-years. PWID were recruited from persons entering substance use treatment programs at Mount Sinai Beth Israel in 2001-2005 and 2011-2015. A structured interview was administered, and HIV and HSV-2 testing was conducted. Incidence was estimated using newly diagnosed cases of HIV. Disparity analyses compared prevalence of HIV, of untreated HIV, HIV risk behaviors, and estimated HIV incidence. By 2011-2015, both heterosexual male and female PWID met the two criteria for an "end of the epidemic," and there were no significant differences in the prevalence of untreated HIV infection. A large sex difference remained in estimated HIV incidence. In 2013-2015, estimated HIV incidence was 2.8/10,000 PY for males and 7.1/10,000 PY for females. Females had greater risk for HIV on several factors. While NYC has reached an "end of the epidemic" for both heterosexual male and female PWID, sex disparities persist, particularly differences in HIV incidence. Eliminating the sex disparities may require a greater focus on factors associated with sexual transmission. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Rationale for an HIV / AIDS prevention and mitigation strategy for Africa: combatting the multisectoral impact of the epidemic.

    Science.gov (United States)

    Lyerly, W H

    1996-01-01

    Unlike most infectious diseases in Africa, HIV/AIDS affects the urban elite as well as the rural poor, and generally during their most economically productive years. An increase in deaths among young adults of the magnitude predicted is likely to have substantial adverse effects on economic, political, and military/security stability throughout Africa. AIDS is causing increased stress on fragile African economic infrastructures as labor productivity declines, particularly in agricultural, labor-dependent economies. AIDS is causing obstacles to trade, foreign investment and tourism. Health systems and social coping mechanisms already are overburdened. High rates of HIV infection among police and military personnel threaten internal security. Furthermore, the demobilization of military forces in Africa may exacerbate the epidemic when HIV-infected soldiers return home and spread the virus. This presentation will illustrate why African AIDS Programs must be expanded to mitigate the multisectoral impact of the epidemic while preserving its spread.

  19. Dynamics analysis of SIR epidemic model with correlation coefficients and clustering coefficient in networks.

    Science.gov (United States)

    Zhang, Juping; Yang, Chan; Jin, Zhen; Li, Jia

    2018-07-14

    In this paper, the correlation coefficients between nodes in states are used as dynamic variables, and we construct SIR epidemic dynamic models with correlation coefficients by using the pair approximation method in static networks and dynamic networks, respectively. Considering the clustering coefficient of the network, we analytically investigate the existence and the local asymptotic stability of each equilibrium of these models and derive threshold values for the prevalence of diseases. Additionally, we obtain two equivalent epidemic thresholds in dynamic networks, which are compared with the results of the mean field equations. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Origin and dynamics of HIV-1 subtype C infection in India.

    Directory of Open Access Journals (Sweden)

    Chengli Shen

    Full Text Available To investigate the geographical origin and evolution dynamics of HIV-1 subtype C infection in India.Ninety HIV-1 subtype C env gp120 subtype C sequences from India were compared with 312 env gp120 reference subtype C sequences from 27 different countries obtained from Los Alamos HIV database. All the HIV-1 subtype C env gp120 sequences from India were used for the geographical origin analysis and 61 subtype C env gp120 sequences with known sampling year (from 1991 to 2008 were employed to determine the origin of HIV infection in India.Phylogenetic analysis of HIV-1 env sequences was used to investigate the geographical origin and tMRCA of Indian HIV-1 subtype C. Evolutionary parameters including origin date and demographic growth patterns of Indian subtype C were estimated using a Bayesian coalescent-based approach under relaxed molecular clock models.The majority of the analyzed Indian and South African HIV-1 subtype C sequences formed a single monophyletic cluster. The most recent common ancestor date was calculated to be 1975.56 (95% HPD, 1968.78-1981.52. Reconstruction of the effective population size revealed three phases of epidemic growth: an initial slow growth, followed by exponential growth, and then a plateau phase approaching present time. Stabilization of the epidemic growth phase correlated with the foundation of National AIDS Control Organization in India.Indian subtype C originated from a single South African lineage in the middle of 1970s. The current study emphasizes not only the utility of HIV-1 sequence data for epidemiological studies but more notably highlights the effectiveness of community or government intervention strategies in controlling the trend of the epidemic.

  1. Stochastic inequalities and applications to dynamics analysis of a novel SIVS epidemic model with jumps

    Directory of Open Access Journals (Sweden)

    Xiaona Leng

    2017-06-01

    Full Text Available Abstract This paper proposes a new nonlinear stochastic SIVS epidemic model with double epidemic hypothesis and Lévy jumps. The main purpose of this paper is to investigate the threshold dynamics of the stochastic SIVS epidemic model. By using the technique of a series of stochastic inequalities, we obtain sufficient conditions for the persistence in mean and extinction of the stochastic system and the threshold which governs the extinction and the spread of the epidemic diseases. Finally, this paper describes the results of numerical simulations investigating the dynamical effects of stochastic disturbance. Our results significantly improve and generalize the corresponding results in recent literatures. The developed theoretical methods and stochastic inequalities technique can be used to investigate the high-dimensional nonlinear stochastic differential systems.

  2. Confronting the HIV epidemic in Asia and the Pacific: developing successful strategies to minimize the spread of HIV infection.

    Science.gov (United States)

    Moodie, R; Aboagye-Kwarteng, T

    1993-12-01

    In Asia, the cumulative total of HIV-infected adults will reach 1.22 million by 1995, and, by 2000, the number is estimated to reach 11-45 million. The modes of transmission vary from country to country and include injecting drug users, commercial sex workers and their clients, commercial blood donors, hemophiliacs, and homosexuals. Social, cultural, and health factors also affect transmission, such as rites of passage to adulthood, lack of female autonomy, multiple sex partners, wars and civil unrest, and availability of drugs. The HIV epidemic has economic ramifications and causes, e.g., migrant worker camps, the sex industry, and rapid urbanization luring Burmese girls to Thailand. Governments must create an environment for behavior-change through financial, political, and legislative measures. Community organizations also play a role in prevention, as in programs initiated by a squatter settlement in Bangkok, where 36% of IV drug users were found to be HIV-positive. In Maharashtra State, India, peer-based prevention programs were developed for sex workers. Successful behavior change of individuals is based on redefinition of peer norms, understanding the danger and vulnerability to infection, and building confidence to change behavior. Successful programs require placing priority on HIV issues on the political agenda, negotiation and consensus-building skills, and competent program management. For instance, in Zimbabwe a project enlisted 380,000 people in 4500 education sessions within 2 years, and distributed 2.5 million condoms. Among sex workers, condom use increased from 5% to 50%. Implementation strategies include the provision of information and interpersonal education. In Zaire, mass media and social marketing efforts boosted condom sales from less than half a million in 1987 to over 20 million in 1991. The means to change behavior requires the availability of good quality condoms, disinfectants, and syringes. Furthermore, clinical management of

  3. The Interaction of Risk Network Structures and Virus Natural History in the Non-spreading of HIV Among People Who Inject Drugs in the Early Stages of the Epidemic.

    Science.gov (United States)

    Dombrowski, Kirk; Khan, Bilal; Habecker, Patrick; Hagan, Holly; Friedman, Samuel R; Saad, Mohamed

    2017-04-01

    This article explores how social network dynamics may have reduced the spread of HIV-1 infection among people who inject drugs during the early years of the epidemic. Stochastic, discrete event, agent-based simulations are used to test whether a "firewall effect" can arise out of self-organizing processes at the actor level, and whether such an effect can account for stable HIV prevalence rates below population saturation. Repeated simulation experiments show that, in the presence of recurring, acute, and highly infectious outbreaks, micro-network structures combine with the HIV virus's natural history to reduce the spread of the disease. These results indicate that network factors likely played a significant role in the prevention of HIV infection within injection risk networks during periods of peak prevalence. They also suggest that social forces that disturb network connections may diminish the natural firewall effect and result in higher rates of HIV.

  4. HIV among gay and other men who have sex with men in Latin America and the Caribbean: a hidden epidemic?

    Science.gov (United States)

    Cáceres, Carlos F

    2002-12-01

    To assess the epidemiological and social/cultural context of, and the social response to, the HIV epidemic among gay and other men who have sex with men (MSM) in Latin America and the Caribbean. A review of epidemiological surveillance reports to the Pan American Health Organization/UNAIDS; published studies on HIV prevalence/incidence among MSM in the region; social/cultural studies on homosexuality; documents analysing risk and vulnerability among MSM and publications documenting the social response to the MSM epidemic. The regional HIV epidemic is concentrated in MSM populations in most urban centres (HIV prevalence 5-20%). Incidence rates (1.5-3.3 in Brazil and Peru) are still moderately high, and call for continued programmatic action. Transmission from bisexual men to women is increasingly observed, demonstrating that the neglect of intervention will fuel co-existent epidemics. MSM in the region are culturally diverse, with mediation of social class, sex, and ethnicity. Around core gay subcultures, non-gay identified MSM interact with them and frequently exchange sex for goods. Examples are shown of sexual meanings affecting prevention messages focused on individual risk, as well as of the role of structural vulnerability on potential exposure to infection, calling for programmes beyond individual rational decision-making. The social response to the AIDS epidemic has, in most countries, included programmes oriented to MSM, usually from civil society organizations, and has strengthened gay organizing. Renewed, imaginative efforts are needed from governments and community organizations to strengthen culturally sensitive prevention work, and integrate it into community empowerment and the promotion of sexual rights.

  5. [HIV/AIDS in South Africa and Haiti: the failure of epidemic governance and achievement of the MDGs].

    Science.gov (United States)

    Thelot, Fils-Lien Ely

    2009-01-01

    Since their adoption in 2000 by the United Nations, the Millennium Development Goals set for 2015 appear to have become a part of the policy agenda of all of the member states. Three of these eight objectives deal with health issues. "Combat HIV/AIDS, malaria and other diseases": this is the formulation of the sixth MDG. Observing that in many countries strongly affected by poverty and inequalities, the epidemic continues to spread, without really reversing at all, and that access to antiretrovirals is possible for only a small proportion of the patient who need them, we consider the problems of global governance in the field of health. Our intention is to explain that the failure to deal with the HIV/AIDS epidemic may constitute an obstacle to the achievement of the MDGs by 2015. Proposing a comprehensive sociology of HIV/AIDS, this article pays special attention to the dimension of the meaning of the disease, simultaneously as a policy issue, a social construction, and an object of study in the social sciences. Looking at the two countries most affected by the epidemic in Africa and in the Caribbean, we examine the different aspects that have determined the failure of governance and the effects of this failure on the populations concerned. The excessive conflictuality in South Africa and the biopolitics of "let them die" and the fragmentation of the networks involved in the combat in Haiti are considered to have contributed to a crisis in the epidemic's governance. In both cases, the consequences have been expressed by a reduced life expectancy, insufficient access to antiretroviral drugs, reinforcement of the socioeconomic inequalities of health, the production of new pockets of poverty, more fragile household and national economies, an increase in maternal and child mortality ... The failure of the governance of the HIV/AIDS epidemic in countries such as Haiti and South Africa appears to foretell the impossibility of achieving the MDGs by 2015.

  6. Suppressing epidemic spreading by risk-averse migration in dynamical networks

    Science.gov (United States)

    Yang, Han-Xin; Tang, Ming; Wang, Zhen

    2018-01-01

    In this paper, we study the interplay between individual behaviors and epidemic spreading in a dynamical network. We distribute agents on a square-shaped region with periodic boundary conditions. Every agent is regarded as a node of the network and a wireless link is established between two agents if their geographical distance is less than a certain radius. At each time, every agent assesses the epidemic situation and make decisions on whether it should stay in or leave its current place. An agent will leave its current place with a speed if the number of infected neighbors reaches or exceeds a critical value E. Owing to the movement of agents, the network's structure is dynamical. Interestingly, we find that there exists an optimal value of E leading to the maximum epidemic threshold. This means that epidemic spreading can be effectively controlled by risk-averse migration. Besides, we find that the epidemic threshold increases as the recovering rate increases, decreases as the contact radius increases, and is maximized by an optimal moving speed. Our findings offer a deeper understanding of epidemic spreading in dynamical networks.

  7. Increasing Rates of Obesity Among HIV-Infected Persons During the HIV Epidemic

    Science.gov (United States)

    2010-04-01

    Sabin CA, Youle M, Madge S, Tyrer M, et al. (1999) Changes in AIDS-defining illnesses in a London clinic, 1987–1998. J Acquir Immune Defic Syndr 21...from the DAD study. AIDS 17: 1179–93. 31. Friis-Møller N, Sabin CA, Weber R, Reiss P, El-Sadr WM, et al. (2003) Data Collection on Adverse Events of Anti...weight. N Engl J Med 341: 427–34. 37. Duran AC, Almeida LB, Segurado AA, Jaime PC (2008) Diet quality of persons living with HIV/AIDS on highly active

  8. Epidemic spreading on dynamical networks with temporary hubs and stable scale-free degree distribution

    International Nuclear Information System (INIS)

    Wu, An-Cai

    2014-01-01

    Recent empirical analyses of some realistic dynamical networks have demonstrated that their degree distributions are stable scale-free (SF), but the instantaneous well-connected hubs at one point of time can quickly become weakly connected. Motivated by these empirical results, we propose a simple toy dynamical agent-to-agent contact network model, in which each agent stays at one node of a static underlay network and the nearest neighbors swap their positions with each other. Although the degree distribution of the dynamical network model at any one time is equal to that in the static underlay network, the numbers and identities of each agent’s contacts will change over time. It is found that the dynamic interaction tends to suppress epidemic spreading in terms of larger epidemic threshold, smaller prevalence (the fraction of infected individuals) and smaller velocity of epidemic outbreak. Furthermore, the dynamic interaction results in the prevalence to undergo a phase transition at a finite threshold of the epidemic spread rate in the thermodynamic limit, which is in contradiction to the absence of an epidemic threshold in static SF networks. Some of these findings obtained from heterogeneous mean-field theory are in good agreement with numerical simulations. (paper)

  9. The impact of multiple information on coupled awareness-epidemic dynamics in multiplex networks

    Science.gov (United States)

    Pan, Yaohui; Yan, Zhijun

    2018-02-01

    Growing interest has emerged in the study of the interplay between awareness and epidemics in multiplex networks. However, previous studies on this issue usually assume that all aware individuals take the same level of precautions, ignoring individual heterogeneity. In this paper, we investigate the coupled awareness-epidemic dynamics in multiplex networks considering individual heterogeneity. Here, the precaution levels are heterogeneous and depend on three types of information: contact information and local and global prevalence information. The results show that contact-based precautions can decrease the epidemic prevalence and augment the epidemic threshold, but prevalence-based precautions, regardless of local or global information, can only decrease the epidemic prevalence. Moreover, unlike previous studies in single-layer networks, we do not find a greater impact of local prevalence information on the epidemic prevalence compared to global prevalence information. In addition, we find that the altruistic behaviors of infected individuals can effectively suppress epidemic spreading, especially when the level of contact-based precaution is high.

  10. A decade of investments in monitoring the HIV epidemic: how far have we come? A descriptive analysis.

    Science.gov (United States)

    Alfven, Tobias; McDougal, Lotus; Frescura, Luisa; Aran, Christian; Amler, Paul; Gill, Wayne

    2014-10-16

    The 2001 Declaration of Commitment (DoC) adopted by the General Assembly Special Session on HIV/AIDS (UNGASS) included a call to monitor national responses to the HIV epidemic. Since the DoC, efforts and investments have been made globally to strengthen countries' HIV monitoring and evaluation (M&E) capacity. This analysis aims to quantify HIV M&E investments, commitments, capacity, and performance during the last decade in order to assess the success and challenges of national and global HIV M&E systems. M&E spending and performance was assessed using data from UNGASS country progress reports. The National Composite Policy Index (NCPI) was used to measure government commitment, government engagement, partner/civil society engagement, and data generation, as well as to generate a composite HIV M&E System Capacity Index (MESCI) score. Analyses were restricted to low and middle income countries (LMICs) who submitted NCPI reports in 2006, 2008, and 2010 (n = 78). Government commitment to HIV M&E increased considerably between 2006 and 2008 but decreased between 2008 and 2010. The percentage of total AIDS spending allocated to HIV M&E increased from 1.1% to 1.4%, between 2007 and 2010, in high-burden LMICs. Partner/civil society engagement and data generation capacity improved between 2006 and 2010 in the high-burden countries. The HIV MESCI increased from 2006 to 2008 in high-burden countries (78% to 94%), as well as in other LMICs (70% to 77%), and remained relatively stable in 2010 (91% in high-burden countries, 79% in other LMICs). Among high-burden countries, M&E system performance increased from 52% in 2006 to 89% in 2010. The last decade has seen increased commitments and spending on HIV M&E, as well as improved M&E capacity and more available data on the HIV epidemic in both high-burden and other LMICs. However, challenges remain in the global M&E of the AIDS epidemic as we approach the 2015 Millennium Development Goal targets.

  11. Racial/Ethnic Disparities at the End of an HIV Epidemic: Persons Who Inject Drugs in New York City, 2011-2015.

    Science.gov (United States)

    Des Jarlais, Don C; Arasteh, Kamyar; McKnight, Courtney; Feelemyer, Jonathan; Tross, Susan; Perlman, David; Friedman, Samuel; Campbell, Aimee

    2017-07-01

    To examine whether racial/ethnic disparities persist at the "end of the HIV epidemic" (prevalence of untreated HIV infection New York City. We recruited 2404 PWID entering New York City substance use treatment in 2001 to 2005 and 2011 to 2015. We conducted a structured interview, and testing for HIV and herpes simplex virus 2 (HSV-2; a biomarker for high sexual risk). We estimated incidence by using newly diagnosed cases of HIV. Disparity analyses compared HIV, untreated HIV, HIV-HSV-2 coinfection, HIV monoinfection, and estimated HIV incidence among Whites, African Americans, and Latinos. By 2011 to 2015, Whites, African Americans, and Latino/as met both criteria of our operational "end-of-the-epidemic" definition. All comparisons that included HIV-HSV-2-coinfected persons had statistically significant higher rates of HIV among racial/ethnic minorities. No comparisons limited to HIV monoinfected persons were significant. "End-of-the-epidemic" criteria were met among White, African American, and Latino/a PWID in New York City, but elimination of disparities may require a greater focus on PWID with high sexual risk.

  12. PREDICTION OF DENGUE FEVER EPIDEMIC SPREADING USING DYNAMICS TRANSMISSION VECTOR MODEL

    Directory of Open Access Journals (Sweden)

    Retno Widyaningrum

    2014-05-01

    Full Text Available Increasing number of dengue cases in Surabaya shows that its city has high potential of dengue fever epidemic. Although some policies were designed by Surabaya Health Department, such as fogging and mosquito’s nest eradication, but these efforts still out of target because of inaccurate predictions. Ineffectiveness eradication of dengue fever epidemic is caused by lack of information and knowledge on environmental conditions in Surabaya. Developing spread and prediction system to minimize dengue fever epidemic is necessary to be conducted immediately. Spread and prediction system can improve eradication and prevention accuracy. The transmission dynamics vector simulation will be used as an approach to draw a complex system ofmosquito life cycle in which involve a lot offactors. Dynamics transmission model used to build model in mosquito model (oviposition rate and pre adult mosquito, infected and death cases in dengue fever. The model of mosquito and infected population can represent system. The output of this research is website of spread and prediction system of dengue fever epidemics to predict growth rate of Aedes Aegypti mosquito, infected, and death population because of dengue fever epidemics. The deviation of infected population is 0,519. The model of death cases in dengue fever is less precision with the deviation 1,229. Death cases model need improvement by adding some variables that influence to dengue fever death cases. Spread ofdengue fever prediction will help the government, health department to decide the best policies in minimizing the spread ofdengue fever epidemics.

  13. 'Taking care' in the age of AIDS: older rural South Africans' strategies for surviving the HIV epidemic.

    Science.gov (United States)

    Angotti, Nicole; Mojola, Sanyu A; Schatz, Enid; Williams, Jill R; Gómez-Olivé, F Xavier

    2018-03-01

    Older adults have been largely overlooked in community studies of HIV in highly endemic African countries. In our rural study site in Mpumalanga Province, South Africa, HIV prevalence among those aged 50 and older is 16.5%, suggesting that older adults are at risk of both acquiring and transmitting HIV. This paper utilises community-based focus-group interviews with older rural South African men and women to better understand the normative environment in which they come to understand and make decisions about their health as they age in an HIV endemic setting. We analyse the dimensions of an inductively emerging theme: ku ti hlayisa (to take care of yourself). For older adults, 'taking care' in an age of AIDS represented: (1) an individualised pathway to achieving old-age respectability through the taking up of responsibilities and behaviours that characterise being an older person, (2) a set of gendered norms and strategies for reducing one's HIV risk, and (3) a shared responsibility for attenuating the impact of the HIV epidemic in the local community. Findings reflect the individual, interdependent and communal ways in which older rural South Africans understand HIV risk and prevention, ways that also map onto current epidemiological thinking for improving HIV-related outcomes in high-prevalence settings.

  14. Sexual learning among East African adolescents in the context of generalized HIV epidemics: A systematic qualitative meta-synthesis.

    Directory of Open Access Journals (Sweden)

    Amelia S Knopf

    Full Text Available AIDS-related illness is the leading cause of mortality for adolescents in sub-Saharan Africa. Together, Kenya, Tanzania, and Uganda account for 21% of HIV-infected adolescents in sub-Saharan Africa. The United Nations framework for addressing the epidemic among adolescents calls for comprehensive sexual and reproductive health education. These HIV prevention efforts could be informed by a synthesis of existing research about the formal and informal sexual education of adolescents in countries experiencing generalized epidemics. The purpose of this study was to describe the process of sexual learning among East African adolescents living in the context of generalized HIV epidemics.Qualitative metasynthesis, a systematic procedure for integrating the results of multiple qualitative studies addressing a similar phenomenon, was used. Thirty-two research reports met study inclusion criteria. The reports were assessed in a four-step analytic process: appraisal, classification of findings, synthesis of findings, and construction of a framework depicting the process of sexual learning in this population.The framework includes three phases of sexual learning: 1 being primed for sex, 2 making sense of sex, and 3 having sexual experiences. Adolescents were primed for sex through gender norms, cultural practices, and economic structures as well as through conversations and formal instruction. They made sense of sex by acquiring information about sexual intercourse, reproduction and pregnancy, sexually transmitted infections, and relationships and by developing a variety of beliefs and attitudes about these topics. Some adolescents described having sexual experiences that met wants or needs, but many experienced sex that was coerced or violent. Whether sex was wanted, coerced, or violent, adolescents experienced worry about sexually transmitted infections or premarital pregnancy.The three phases of sexual learning interact to shape adolescents' sexual lives

  15. Dynamics of tax evasion through an epidemic-like model

    Science.gov (United States)

    Brum, Rafael M.; Crokidakis, Nuno

    In this work, we study a model of tax evasion. We considered a fixed population divided in three compartments, namely honest tax payers, tax evaders and a third class between the mentioned two, which we call susceptibles to become evaders. The transitions among those compartments are ruled by probabilities, similarly to a model of epidemic spreading. These probabilities model social interactions among the individuals, as well as the government’s fiscalization. We simulate the model on fully-connected graphs, as well as on scale-free and random complex networks. For the fully-connected and random graph cases, we observe that the emergence of tax evaders in the population is associated with an active-absorbing nonequilibrium phase transition, that is absent in scale-free networks.

  16. Global dynamics of a dengue epidemic mathematical model

    Energy Technology Data Exchange (ETDEWEB)

    Cai Liming [Department of Mathematics, Xinyang Normal University, Xinyang 464000 (China); Academy of Mathematics and Systems Science, Academia Sinica, Beijing 100080 (China)], E-mail: lmcai06@yahoo.com.cn; Guo Shumin [Beijing Institute of Information Control, Beijing 100037 (China); Li, XueZhi [Department of Mathematics, Xinyang Normal University, Xinyang 464000 (China); Ghosh, Mini [School of Mathematics and Computer Application, Thapar University, Patiala 147004 (India)

    2009-11-30

    The paper investigates the global stability of a dengue epidemic model with saturation and bilinear incidence. The constant human recruitment rate and exponential natural death, as well as vector population with asymptotically constant population, are incorporated into the model. The model exhibits two equilibria, namely, the disease-free equilibrium and the endemic equilibrium. The stability of these two equilibria is controlled by the threshold number R{sub 0}. It is shown that if R{sub 0} is less than one, the disease-free equilibrium is globally asymptotically stable and in such a case the endemic equilibrium does not exist; if R{sub 0} is greater than one, then the disease persists and the unique endemic equilibrium is globally asymptotically stable.

  17. Global dynamics of a dengue epidemic mathematical model

    International Nuclear Information System (INIS)

    Cai Liming; Guo Shumin; Li, XueZhi; Ghosh, Mini

    2009-01-01

    The paper investigates the global stability of a dengue epidemic model with saturation and bilinear incidence. The constant human recruitment rate and exponential natural death, as well as vector population with asymptotically constant population, are incorporated into the model. The model exhibits two equilibria, namely, the disease-free equilibrium and the endemic equilibrium. The stability of these two equilibria is controlled by the threshold number R 0 . It is shown that if R 0 is less than one, the disease-free equilibrium is globally asymptotically stable and in such a case the endemic equilibrium does not exist; if R 0 is greater than one, then the disease persists and the unique endemic equilibrium is globally asymptotically stable.

  18. PROVIDING WOMEN, KEPT MEN: Doing Masculinity in the wake of the African HIV/AIDS epidemic.

    Science.gov (United States)

    Mojola, Sanyu A

    2014-01-01

    This paper draws on ethnographic and interview based fieldwork to explore accounts of intimate relationships between widowed women and poor young men that emerged in the wake of economic crisis and a devastating HIV epidemic among the Luo ethnic group in Western Kenya. I show how the cooptation of widow inheritance practices in the wake of an overwhelming number of widows as well as economic crisis resulted in widows becoming providing women and poor young men becoming kept men. I illustrate how widows in this setting, by performing a set of practices central to what it meant to be a man in this society - pursuing and providing for their partners - were effectively doing masculinity. I will also show how young men, rather than being feminized by being kept, deployed other sets of practices to prove their masculinity and live in a manner congruent with cultural ideals. I argue that ultimately, women's practice of masculinity in large part seemed to serve patriarchal ends. It not only facilitated the fulfillment of patriarchal expectations of femininity - to being inherited - but also served, in the end, to provide a material base for young men's deployment of legitimizing and culturally valued sets of masculine practice.

  19. IMPACT OF MIGRATION ON TUBERCULOSIS AND HIV EPIDEMIC SITUATION IN RUSSIA

    Directory of Open Access Journals (Sweden)

    O. B. Nechaeva

    2015-01-01

    Full Text Available The growing changes in migration and mobility of the population in Russia require additional study of the epidemic situation related to infectious diseases and evaluation of preparedness of specialized medical services and existing resources of the health care system. Assessment of the incidence rates shows the higher figures among foreign citizens compared to native population as regards tuberculosis (2013: 163.2 versus 61.6 per 100,000 population and lower figures for HIV-infection (107.5 versus 315.1 respectively.The study of behavioral risks of acquiring infectious diseases (HIV-infection, sexually transmitted diseases, tuberculosis and socio-economic living conditions and factors influencing on the self-referral to the Russian medical units conducted among labor migrants in St. Petersburg, showed fairly low level of awareness of socially important diseases and protection from infections in migrants. Due to the fear of deportation in case of detection of infectious diseases, high price of medical services and lack of motivation of the employer to pay for medical insurance, migrants often practice self-treatment. Very few migrants (10% present themselves for mandatory annual fluorography screening.A significant flow of refugees from Ukraine especially from the regions with high risk of infectious diseases require special attention from the Russian Ministry of Health and the relevant financial support.There is also a lack of cooperation between bodies of Rospotrebnadzor and medical units submitting data on notifications of HIV-infection and tuberculosis in foreign citizens. Coordination mechanisms have to be improved to overcome the found deficiencies. 

  20. Dynamic Variation in Sexual Contact Rates in a Cohort of HIV-Negative Gay Men.

    Science.gov (United States)

    Romero-Severson, E O; Volz, E; Koopman, J S; Leitner, T; Ionides, E L

    2015-08-01

    Human immunodeficiency virus (HIV) transmission models that include variability in sexual behavior over time have shown increased incidence, prevalence, and acute-state transmission rates for a given population risk profile. This raises the question of whether dynamic variation in individual sexual behavior is a real phenomenon that can be observed and measured. To study this dynamic variation, we developed a model incorporating heterogeneity in both between-person and within-person sexual contact patterns. Using novel methodology that we call iterated filtering for longitudinal data, we fitted this model by maximum likelihood to longitudinal survey data from the Centers for Disease Control and Prevention's Collaborative HIV Seroincidence Study (1992-1995). We found evidence for individual heterogeneity in sexual behavior over time. We simulated an epidemic process and found that inclusion of empirically measured levels of dynamic variation in individual-level sexual behavior brought the theoretical predictions of HIV incidence into closer alignment with reality given the measured per-act probabilities of transmission. The methods developed here provide a framework for quantifying variation in sexual behaviors that helps in understanding the HIV epidemic among gay men. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  1. Who is epidemiologically fathomable in the HIV/AIDS epidemic? Gender, sexuality, and intersectionality in public health

    Science.gov (United States)

    Dworkin, Shari L.

    2014-01-01

    This paper examines the shifting nature of contemporary epidemiological classifications in the HIV/ AIDS epidemic. It first looks at assumptions that guide a discourse of vulnerability and circulate around risk categories. It then examines the underlying emphasis in public health on the popular frame of “vulnerable women” who acquire HIV through heterosexual transmission. Drawing on work on gender, sexuality, and intersectionality, the paper asks why a discourse of vulnerability is infused into discussions of heterosexually-active women's HIV risks but not those pertaining to heterosexually-active men's. The paper then moves to current surveillance categories that are hierarchically and differentially applied to women's and men's risks in the HIV epidemic. Here, the focus is on the way in which contemporary classifications allow for the emergence of the vulnerable heterosexually-active woman while simultaneously constituting lack of fathomability concerning bisexual and lesbian transmission risk. Lastly, theories of intersectionality, are used to examine current research on woman-to-woman transmission, and to suggest future more productive options. PMID:16864226

  2. Dynamic behavior of the interaction between epidemics and cascades on heterogeneous networks

    Science.gov (United States)

    Jiang, Lurong; Jin, Xinyu; Xia, Yongxiang; Ouyang, Bo; Wu, Duanpo

    2014-12-01

    Epidemic spreading and cascading failure are two important dynamical processes on complex networks. They have been investigated separately for a long time. But in the real world, these two dynamics sometimes may interact with each other. In this paper, we explore a model combined with the SIR epidemic spreading model and a local load sharing cascading failure model. There exists a critical value of the tolerance parameter for which the epidemic with high infection probability can spread out and infect a fraction of the network in this model. When the tolerance parameter is smaller than the critical value, the cascading failure cuts off the abundance of paths and blocks the spreading of the epidemic locally. While the tolerance parameter is larger than the critical value, the epidemic spreads out and infects a fraction of the network. A method for estimating the critical value is proposed. In simulations, we verify the effectiveness of this method in the uncorrelated configuration model (UCM) scale-free networks.

  3. Geographic variation in sexual behavior can explain geospatial heterogeneity in the severity of the HIV epidemic in Malawi.

    Science.gov (United States)

    Palk, Laurence; Blower, Sally

    2018-02-09

    In sub-Saharan Africa, where ~ 25 million individuals are infected with HIV and transmission is predominantly heterosexual, there is substantial geographic variation in the severity of epidemics. This variation has yet to be explained. Here, we propose that it is due to geographic variation in the size of the high-risk group (HRG): the group with a high number of sex partners. We test our hypothesis by conducting a geospatial analysis of data from Malawi, where ~ 13% of women and ~ 8% of men are infected with HIV. We used georeferenced HIV testing and behavioral data from ~ 14,000 participants of a nationally representative population-level survey: the 2010 Malawi Demographic and Health Survey (MDHS). We constructed gender-stratified epidemic surface prevalence (ESP) maps by spatially smoothing and interpolating the HIV testing data. We used the behavioral data to construct gender-stratified risk maps that reveal geographic variation in the size of the HRG. We tested our hypothesis by fitting gender-stratified spatial error regression (SER) models to the MDHS data. The ESP maps show considerable geographic variation in prevalence: 1-29% (women), 1-20% (men). Risk maps reveal substantial geographic variation in the size of the HRG: 0-40% (women), 16-58% (men). Prevalence and the size of the HRG are highest in urban centers. However, the majority of HIV-infected individuals (~75% of women, ~ 80% of men) live in rural areas, as does most of the HRG (~ 80% of women, ~ 85% of men). We identify a significant (P national average in districts where > 20% of women are in the HRG. Most importantly, the SER models show that geographic variation in the size of the HRG can explain a substantial proportion (73% for women, 67% for men) of the geographic variation in epidemic severity. Taken together, our results provide substantial support for our hypothesis. They provide a potential mechanistic explanation for the geographic variation in the severity

  4. Neoliberal Governance in the HIV and AIDS Epidemic Among Mexican Women in Mexico: the Effects of the Paradigm of Vulnerability

    Directory of Open Access Journals (Sweden)

    Ana Amuchástegui

    2017-05-01

    Full Text Available The response to the HIV epidemics in Mexico is supported by the neoliberal governance paradigm of vulnerability, in such a way that a government organization of suffering distributes resources among “key populations”. This article discusses the way in which this strategy, oriented by the moral regulation of sexuality, works simultaneously as raison d’etre and straitjacket for feminist and women with HIV organizations, making difficult alliances between them. This discussion is carried out through an analysis of ethnographic material and an intervention-research with and for women affected by HIV. Their biographies show multiple forms of resistance, suggesting the necessity of questioning their self-representation as impotent subjects, and of problematizing, as a task of feminism, the dichotomy vulnerability-resistance.

  5. Dynamics of epidemic spreading with vaccination: Impact of social pressure and engagement

    Science.gov (United States)

    Pires, Marcelo A.; Crokidakis, Nuno

    2017-02-01

    In this work we consider a model of epidemic spreading coupled with an opinion dynamics in a fully-connected population. Regarding the opinion dynamics, the individuals may be in two distinct states, namely in favor or against a vaccination campaign. Individuals against the vaccination follow a standard SIS model, whereas the pro-vaccine individuals can also be in a third compartment, namely Vaccinated. In addition, the opinions change according to the majority-rule dynamics in groups with three individuals. We also consider that the vaccine can give permanent or temporary immunization to the individuals. By means of analytical calculations and computer simulations, we show that the opinion dynamics can drastically affect the disease propagation, and that the engagement of the pro-vaccine individuals can be crucial for stopping the epidemic spreading. The full numerical code for simulating the model is available from the authors' webpage.

  6. Dynamic complexities in a seasonal prevention epidemic model with birth pulses

    International Nuclear Information System (INIS)

    Gao Shujing; Chen Lansun; Sun Lihua

    2005-01-01

    In most of population dynamics, increases in population due to birth are assumed to be time-dependent, but many species reproduce only during a single period of the year. In this paper, we propose an epidemic model with density-dependent birth pulses and seasonal prevention. Using the discrete dynamical system determined by stroboscopic map, we obtain the local or global stability, numerical simulation shows there is a characteristic sequence of bifurcations, leading to chaotic dynamics, which implies that the dynamical behaviors of the epidemic model with birth pulses and seasonal prevention are very complex, including small amplitude oscillations, large-amplitude multi-annual cycles and chaos. This suggests that birth pulse, in effect, provides a natural period or cyclicity that may lead a period-doubling route to chaos

  7. Sexual risk factors for HIV infection in early and advanced HIV epidemics in sub-Saharan Africa: systematic overview of 68 epidemiological studies.

    Directory of Open Access Journals (Sweden)

    Li Chen

    2007-10-01

    Full Text Available It is commonly assumed that sexual risk factors for heterosexual HIV transmission in sub-Saharan Africa, such as multi-partner sex, paid sex and co-infections, become less important as HIV epidemics mature and prevalence increases.We conducted a systematic review of 68 African epidemiological studies from 1986 to 2006 involving 17,000 HIV positive adults and 73,000 controls. We used random-effects methods and stratified results by gender, time, background HIV prevalence rates and other variables. The number of sex partners, history of paid sex, and infection with herpes simplex virus (HSV-2 or other sexually-transmitted infections (STIs each showed significant associations with HIV infection. Among the general population, the odds ratio (OR of HIV infection for women reporting 3+ sex partners versus 0-2 was 3.64 (95%CI [2.87-4.62], with similar risks for men. About 9% of infected women reported ever having been paid for sex, versus 4% of control women (OR = 2.29, [1.45-3.62]. About 31% of infected men reported ever paying for sex versus 18% of uninfected men (OR = 1.75, [1.30-2.36]. HSV-2 infection carried the largest risk of HIV infection: OR = 4.62, [2.85-7.47] in women, and OR = 6.97, [4.68-10.38] in men. These risks changed little over time and stratification by lower and higher HIV background prevalence showed that risk ratios for most variables were larger in high prevalence settings. Among uninfected controls, the male-female differences in the number of sex partners and in paid sex were more extreme in the higher HIV prevalence settings than in the lower prevalence settings.Multi-partner sex, paid sex, STIs and HSV-2 infection are as important to HIV transmission in advanced as in early HIV epidemics. Even in high prevalence settings, prevention among people with high rates of partner change, such as female sex workers and their male clients, is likely to reduce transmission overall.

  8. Effects of human dynamics on epidemic spreading in Côte d'Ivoire

    Science.gov (United States)

    Li, Ruiqi; Wang, Wenxu; Di, Zengru

    2017-02-01

    Understanding and predicting outbreaks of contagious diseases are crucial to the development of society and public health, especially for underdeveloped countries. However, challenging problems are encountered because of complex epidemic spreading dynamics influenced by spatial structure and human dynamics (including both human mobility and human interaction intensity). We propose a systematical model to depict nationwide epidemic spreading in Côte d'Ivoire, which integrates multiple factors, such as human mobility, human interaction intensity, and demographic features. We provide insights to aid in modeling and predicting the epidemic spreading process by data-driven simulation and theoretical analysis, which is otherwise beyond the scope of local evaluation and geometrical views. We show that the requirement that the average local basic reproductive number to be greater than unity is not necessary for outbreaks of epidemics. The observed spreading phenomenon can be roughly explained as a heterogeneous diffusion-reaction process by redefining mobility distance according to the human mobility volume between nodes, which is beyond the geometrical viewpoint. However, the heterogeneity of human dynamics still poses challenges to precise prediction.

  9. Theorizing "Big Events" as a potential risk environment for drug use, drug-related harm and HIV epidemic outbreaks.

    Science.gov (United States)

    Friedman, Samuel R; Rossi, Diana; Braine, Naomi

    2009-05-01

    Political-economic transitions in the Soviet Union, Indonesia, and China, but not the Philippines, were followed by HIV epidemics among drug users. Wars also may sometimes increase HIV risk. Based on similarities in some of the causal pathways through which wars and transitions can affect HIV risk, we use the term "Big Events" to include both. We first critique several prior epidemiological models of Big Events as inadequately incorporating social agency and as somewhat imprecise and over-generalizing in their sociology. We then suggest a model using the following concepts: first, event-specific HIV transmission probabilities are functions of (a) the probability that partners are infection-discordant; (b) the infection-susceptibility of the uninfected partner; (c) the infectivity of the infected--as well as (d) the behaviours engaged in. These probabilities depend on the distributions of HIV and other variables in populations. Sexual or injection events incorporate risk behaviours and are embedded in sexual and injection partnership patterns and community networks, which in turn are shaped by the content of normative regulation in communities. Wars and transitions can change socio-economic variables that can sometimes precipitate increases in the numbers of people who engage in high-risk drug and sexual networks and behaviours and in the riskiness of what they do. These variables that Big Events affect may include population displacement; economic difficulties and policies; police corruption, repressiveness, and failure to preserve order; health services; migration; social movements; gender roles; and inter-communal violence--which, in turn, affect normative regulation, youth alienation, networks and behaviours. As part of these pathways, autonomous action by neighbourhood residents, teenagers, drug users and sex workers to maintain their economic welfare, health or happiness may affect many of these variables or otherwise mediate whether HIV epidemics follow

  10. On the oscillatory dynamical behaviour of epidemic spreading in fractal media

    International Nuclear Information System (INIS)

    Bab, M A; Albano, E V

    2008-01-01

    We present numerical evidence that dynamical physical processes that develop a time-dependent characteristic length, and take place in fractal media exhibiting spatial discrete scale invariance (DSI) with fundamental scaling ratio b, may become coupled to the topology of the fractal leading to the observation of time DSI. The hallmark of time DSI is the observation of a log-periodic modulation of the dynamic or kinetic observables, which is characterized by a well-defined fundamental time scaling ratio (τ). Both fundamental scaling ratios are linked according to b = τ 1/z , where z is the dynamic exponent characteristic of the physical process. Specifically, we have studied the epidemic behaviour of the contact process (CP) in Sierpinski Carpets. The CP exhibits second-order irreversible phase transitions between an active regime and an absorbing state where the system is trapped without any escape possibility. We observed that relevant dynamic observables, such as the number of active sites, the survival probability of the epidemics and the mean square displacement of the epidemic from the origin (R 2 (t)), exhibit log-periodic modulations. By fitting the data we evaluate the fundamental time scaling ratio for various fractals and the corresponding dynamic exponents. Since, at criticality, one has that R 2 (t) ∼ t 2/z , an independent estimation of the dynamic exponent can be performed, in excellent agreement with results obtained by using the conjectured relationship for the fundamental scaling ratios b and τ

  11. On the oscillatory dynamical behaviour of epidemic spreading in fractal media

    Energy Technology Data Exchange (ETDEWEB)

    Bab, M A; Albano, E V [Instituto de Investigaciones FisicoquImicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, UNLP, CONICET, Casilla de Correo 16, Sucursal 4 (1900) La Plata (Argentina)

    2008-02-01

    We present numerical evidence that dynamical physical processes that develop a time-dependent characteristic length, and take place in fractal media exhibiting spatial discrete scale invariance (DSI) with fundamental scaling ratio b, may become coupled to the topology of the fractal leading to the observation of time DSI. The hallmark of time DSI is the observation of a log-periodic modulation of the dynamic or kinetic observables, which is characterized by a well-defined fundamental time scaling ratio ({tau}). Both fundamental scaling ratios are linked according to b = {tau}{sup 1/z}, where z is the dynamic exponent characteristic of the physical process. Specifically, we have studied the epidemic behaviour of the contact process (CP) in Sierpinski Carpets. The CP exhibits second-order irreversible phase transitions between an active regime and an absorbing state where the system is trapped without any escape possibility. We observed that relevant dynamic observables, such as the number of active sites, the survival probability of the epidemics and the mean square displacement of the epidemic from the origin (R{sup 2}(t)), exhibit log-periodic modulations. By fitting the data we evaluate the fundamental time scaling ratio for various fractals and the corresponding dynamic exponents. Since, at criticality, one has that R{sup 2}(t) {approx} t{sup 2/z}, an independent estimation of the dynamic exponent can be performed, in excellent agreement with results obtained by using the conjectured relationship for the fundamental scaling ratios b and {tau}.

  12. Review on the epidemiology and dynamics of BSE epidemics.

    Science.gov (United States)

    Ducrot, Christian; Arnold, Mark; de Koeijer, Aline; Heim, Dagmar; Calavas, Didier

    2008-01-01

    The paper describes how the comprehensive surveillance of bovine spongiform encephalopathy (BSE) and studies carried out on these data has enhanced our knowledge of the epidemiology of BSE. Around 7, 000 BSE cases were detected through the screening of about 50 million cattle with rapid tests in Europe. It confirmed that the clinical surveillance had a poor capacity to detect cases, and also showed the discrepancy of this passive surveillance efficiency between regions and production types (dairy/beef). Other risk factors for BSE were being in a dairy herd (three times more than beef), having a young age at first calving (for dairy cattle), being autumn-born (dairy and beef), and being in a herd with a very high milk yield. These findings focus the risk on the feeding regimen of calves/heifers. Several epidemiological studies across countries suggest that the feedborne source related to meat and bone meal (MBM) is the only substantiated route of infection - even after the feed ban -, while it is not possible to exclude maternal transmission or milk replacers as a source of some infections. In most European countries, the average age of the cases is increasing over time and the prevalence decreasing, which reflects the effectiveness of control measures. Consistent results on the trend of the epidemic were obtained using back-calculation modelling, the R(0) approach and Age-Period-Cohort models. Furthermore, active surveillance also resulted in the finding of atypical cases. These are distinct from previously found BSE and classified in two different forms based on biochemical characteristics; their prevalence is very low (36 cases up to 1st September 2007), affected animals were old and some of them displayed clinical signs. The origin and possibility of natural transmission is unknown.

  13. HIV INFECTION AMONG FEMALE SEX WORKERS IN CONCENTRATED AND HIGH PREVALENCE EPIDEMICS: WHY A STRUCTURAL DETERMINANTS FRAMEWORK IS NEEDED

    Science.gov (United States)

    Shannon, Kate; Goldenberg, Shira M.; Deering, Kathleen N.; Strathdee, Steffanie A.

    2014-01-01

    Purpose of review This article reviews the current state of the epidemiological literature on female sex work and HIV from the past 18 months. We offer a conceptual framework for structural HIV determinants and sex work that unpacks intersecting structural, interpersonal, and individual biological and behavioural factors. Recent findings Our review suggests that despite the heavy HIV burden among female sex workers (FSWs) globally, data on the structural determinants shaping HIV transmission dynamics have only begun to emerge. Emerging research suggests that factors operating at macrostructural (e.g., migration, stigma, criminalized laws), community organization (e.g., empowerment) and work environment levels (e.g., violence, policing, access to condoms HIV testing, HAART) act dynamically with interpersonal (e.g., dyad factors, sexual networks) and individual biological and behavioural factors to confer risks or protections for HIV transmission in female sex work. Summary Future research should be guided by a Structural HIV Determinants Framework to better elucidate the complex and iterative effects of structural determinants with interpersonal and individual biological and behavioural factors on HIV transmission pathways among FSWs, and meet critical gaps in optimal access to HIV prevention, treatment, and care for FSWs globally. PMID:24464089

  14. What drives the US and Peruvian HIV epidemics in men who have sex with men (MSM?

    Directory of Open Access Journals (Sweden)

    Steven M Goodreau

    Full Text Available In this work, we estimate the proportions of transmissions occurring in main vs. casual partnerships, and by the sexual role, infection stage, and testing and treatment history of the infected partner, for men who have sex with men (MSM in the US and Peru. We use dynamic, stochastic models based in exponential random graph models (ERGMs, obtaining inputs from multiple large-scale MSM surveys. Parallel main partnership and casual sexual networks are simulated. Each man is characterized by age, race, circumcision status, sexual role behavior, and propensity for unprotected anal intercourse (UAI; his history is modeled from entry into the adult population, with potential transitions including HIV infection, detection, treatment, AIDS diagnosis, and death. We implemented two model variants differing in assumptions about acute infectiousness, and assessed sensitivity to other key inputs. Our two models suggested that only 4-5% (Model 1 or 22-29% (Model 2 of HIV transmission results from contacts with acute-stage partners; the plurality (80-81% and 49%, respectively stem from chronic-stage partners and the remainder (14-16% and 27-35%, respectively from AIDS-stage partners. Similar proportions of infections stem from partners whose infection is undiagnosed (24-31%, diagnosed but untreated (36-46%, and currently being treated (30-36%. Roughly one-third of infections (32-39% occur within main partnerships. Results by country were qualitatively similar, despite key behavioral differences; one exception was that transmission from the receptive to insertive partner appears more important in Peru (34% than the US (21%. The broad balance in transmission contexts suggests that education about risk, careful assessment, pre-exposure prophylaxis, more frequent testing, earlier treatment, and risk-reduction, disclosure, and adherence counseling may all contribute substantially to reducing the HIV incidence among MSM in the US and Peru.

  15. The EuroSIDA study: Regional differences in the HIV-1 epidemic and treatment response to antiretroviral therapy among HIV-infected patients across Europe--a review of published results

    DEFF Research Database (Denmark)

    Podlekareva, Daria; Bannister, Wendy; Mocroft, Amanda

    2008-01-01

    EuroSIDA is a pan-European observational study that follows 14,265 HIV-infected patients from 31 European countries, Israel and Argentina, of which 2,560 are patients from eastern Europe (EE). The study group has performed several analyses addressing regional differences in the HIV-epidemic across...

  16. What do young adults know about the HIV/AIDS epidemic? Findings from a population based study in Karachi, Pakistan.

    Science.gov (United States)

    Farid-ul-Hasnain, Syed; Johansson, Eva; Krantz, Gunilla

    2009-03-26

    HIVAIDS is spreading globally, hitting the younger generations. In Pakistan, the prevalence of HIV in high-risk subpopulations is five per cent or higher. This poses a serious threat of a generalised epidemic especially among the younger population. In the wake of HIVAIDS epidemic this is worrying as a well informed younger generation is crucial in restricting the spread of this epidemic. This study investigated Pakistani young adults' (male and female) knowledge and awareness of the HIV/AIDS disease. A population-based, cross-sectional study of 1,650 male and female adults aged 17-21 years living in Karachi was conducted using a structured questionnaire. A multi-stage cluster sampling design was used to collect data representative of the general population in an urban area. Bivariate and multivariate analyses were performed separately for males and females. Of 1,650 subjects, 24 per cent (n = 390) reported that they had not heard of HIV/AIDS. Among the males, those with a poor knowledge were younger (AOR = 2.20; 95 per cent CI, 1.38, 3.49), with less than six years of schooling (AOR = 2.46; 1.29 4.68) and no computer at home (AOR = 1.88; 1.06 3.34). Among the females, the risk factors for poor knowledge were young age (AOR = 1.74; 1.22, 2.50), low socio-economic status (AOR = 1.54; 1.06, 2.22), lack of enrolment at school/college (AOR = 1.61; 1.09, 2.39) and being unmarried (AOR = 1.85; 1.05, 3.26). Alarming gaps in knowledge relating to HIV/AIDS were detected. The study emphasises the need to educate young adults and equip them with the appropriate information and skills to enable them to protect themselves from HIV/AIDS. However, taboos surrounding public discussions of sexuality remain a key constraint to preventive activities.

  17. What do young adults know about the HIV/AIDS epidemic? Findings from a population based study in Karachi, Pakistan

    Directory of Open Access Journals (Sweden)

    Johansson Eva

    2009-03-01

    Full Text Available Abstract Background HIVAIDS is spreading globally, hitting the younger generations. In Pakistan, the prevalence of HIV in high-risk subpopulations is five per cent or higher. This poses a serious threat of a generalised epidemic especially among the younger population. In the wake of HIVAIDS epidemic this is worrying as a well informed younger generation is crucial in restricting the spread of this epidemic. This study investigated Pakistani young adults' (male and female knowledge and awareness of the HIV/AIDS disease. Methods A population-based, cross-sectional study of 1,650 male and female adults aged 17–21 years living in Karachi was conducted using a structured questionnaire. A multi-stage cluster sampling design was used to collect data representative of the general population in an urban area. Bivariate and multivariate analyses were performed separately for males and females. Results Of 1,650 subjects, 24 per cent (n = 390 reported that they had not heard of HIV/AIDS. Among the males, those with a poor knowledge were younger (AOR = 2.20; 95 per cent CI, 1.38, 3.49, with less than six years of schooling (AOR = 2.46; 1.29 4.68 and no computer at home (AOR = 1.88; 1.06 3.34. Among the females, the risk factors for poor knowledge were young age (AOR = 1.74; 1.22, 2.50, low socio-economic status (AOR = 1.54; 1.06, 2.22, lack of enrolment at school/college (AOR = 1.61; 1.09, 2.39 and being unmarried (AOR = 1.85; 1.05, 3.26. Conclusion Alarming gaps in knowledge relating to HIV/AIDS were detected. The study emphasises the need to educate young adults and equip them with the appropriate information and skills to enable them to protect themselves from HIV/AIDS. However, taboos surrounding public discussions of sexuality remain a key constraint to preventive activities.

  18. Complex dynamics of an SEIR epidemic model with saturated incidence rate and treatment

    Science.gov (United States)

    Khan, Muhammad Altaf; Khan, Yasir; Islam, Saeed

    2018-03-01

    In this paper, we describe the dynamics of an SEIR epidemic model with saturated incidence, treatment function, and optimal control. Rigorous mathematical results have been established for the model. The stability analysis of the model is investigated and found that the model is locally asymptotically stable when R0 1. The proposed model may possess a backward bifurcation. The optimal control problem is designed and obtained their necessary results. Numerical results have been presented for justification of theoretical results.

  19. Global Dynamics of Avian Influenza Epidemic Models with Psychological Effect

    Directory of Open Access Journals (Sweden)

    Sanhong Liu

    2015-01-01

    Full Text Available Cross-sectional surveys conducted in Thailand and China after the outbreaks of the avian influenza A H5N1 and H7N9 viruses show a high degree of awareness of human avian influenza in both urban and rural populations, a higher level of proper hygienic practice among urban residents, and in particular a dramatically reduced number of visits to live markets in urban population after the influenza A H7N9 outbreak in China in 2013. In this paper, taking into account the psychological effect toward avian influenza in the human population, a bird-to-human transmission model in which the avian population exhibits saturation effect is constructed. The dynamical behavior of the model is studied by using the basic reproduction number. The results demonstrate that the saturation effect within avian population and the psychological effect in human population cannot change the stability of equilibria but can affect the number of infected humans if the disease is prevalent. Numerical simulations are given to support the theoretical results and sensitivity analyses of the basic reproduction number in terms of model parameters that are performed to seek for effective control measures for avian influenza.

  20. Global dynamics of avian influenza epidemic models with psychological effect.

    Science.gov (United States)

    Liu, Sanhong; Pang, Liuyong; Ruan, Shigui; Zhang, Xinan

    2015-01-01

    Cross-sectional surveys conducted in Thailand and China after the outbreaks of the avian influenza A H5N1 and H7N9 viruses show a high degree of awareness of human avian influenza in both urban and rural populations, a higher level of proper hygienic practice among urban residents, and in particular a dramatically reduced number of visits to live markets in urban population after the influenza A H7N9 outbreak in China in 2013. In this paper, taking into account the psychological effect toward avian influenza in the human population, a bird-to-human transmission model in which the avian population exhibits saturation effect is constructed. The dynamical behavior of the model is studied by using the basic reproduction number. The results demonstrate that the saturation effect within avian population and the psychological effect in human population cannot change the stability of equilibria but can affect the number of infected humans if the disease is prevalent. Numerical simulations are given to support the theoretical results and sensitivity analyses of the basic reproduction number in terms of model parameters that are performed to seek for effective control measures for avian influenza.

  1. Mixed results: the protective role of schooling in the HIV epidemic in ...

    African Journals Online (AJOL)

    It is recognised that young women, especially adolescents, are particularly vulnerable to HIV infection and bear a disproportionate burden of HIV incidence. The HIV data from Swaziland show the ... although there are challenges. Keywords: dropouts, education, orphans and vulnerable children, repeaters, young women ...

  2. HIV Prevalence Trends, Risky Behaviours, and Governmental and Community Responses to the Epidemic among Men Who Have Sex with Men in China

    Directory of Open Access Journals (Sweden)

    Eric P. F. Chow

    2014-01-01

    Full Text Available Purpose of Review. Numerous studies reported the rapid spread of HIV/AIDS epidemic among men who have sex with men (MSM in China. This paper aims to investigate the overall epidemic trend and associated high-risk behaviours among Chinese MSM and to explore the governmental and community responses to the epidemic. Recent Findings. HIV prevalence among Chinese MSM increased rapidly in all Chinese regions in the past decade and disproportionally affected the Southwest China. In addition to the high-risk homosexual behaviours, overlapping bisexual, commercial, and drug use behaviours are commonly observed among Chinese MSM. The Chinese government has significantly expanded the surveillance efforts among MSM over the past decade. Community responses against HIV have been substantially strengthened with the support of international aid. However, lack of enabling legal and financial environment undermines the role of community-based organisations (CBOs in HIV surveillance and prevention. Conclusion. HIV continues to spread rapidly among MSM in China. The hidden nature of MSM and the overlapping homosexual, bisexual, and commercial behaviours remain a challenge for HIV prevention among MSM. Strong collaboration between the government and CBOs and innovative intervention approaches are essential for effective HIV surveillance and prevention among MSM in China.

  3. Corporate social responsibility in public health: A case-study on HIV/AIDS epidemic by Johnson & Johnson company in Africa

    OpenAIRE

    Chattu, Vijay Kumar

    2015-01-01

    HIV/AIDS has claimed millions of lives in the global workforce and continues to remain a threat to many businesses. An estimated 36.5 million of working people are living with HIV; the global workforce has lost 28 million people from AIDS since the beginning of the epidemic. In the absence of access to treatment, this number could grow to 74 million by 2015. The epidemic continues to affect the working population through absenteeism, sickness and death. Corporate Social Responsibility (CSR) i...

  4. The dynamics of HIV transmission in out of school young heterosexual men in South Africa: a systematic scoping review protocol.

    Science.gov (United States)

    Ntombela, Nonzwakazi; Mashamba-Thompson, Tivani P; Mtshali, Andile; Voce, Anna; Kharsany, Ayesha B M

    2017-01-17

    In South Africa, gender inequality dominated by males and heterosexual HIV epidemic are associated with high HIV infection. Underlying epidemiological and social determinants driving HIV acquisition and transmission are critical to understand the extent and complexity of sexual networks as primary mechanisms through which HIV is likely to spread. The aim of the study is to provide an overview of empiric evidence that links the complex interaction of risk of HIV infection in men. We will conduct a systematic scoping review to identify, describe, and map literature on the dynamics of HIV infection in men, and we will determine the quality of the studies reporting on the dynamics of HIV infections in men. Primary research articles, published in peer-reviewed journals, review articles, and gray literature that address the research question, will be included. We will search PubMed, Web of Knowledge, Science Direct, EBSCOhost, Google Scholar, World Health Organization library, and UNAIDS database. Reference lists and existing networks such as government organizations and conferences will also be included to source relevant literature. Two independent reviewers will extract data in parallel from all relevant search engines, using specific inclusion and exclusion criteria. A thematic content analysis will be used to present the narrative account of the reviews, using NVivo version 10. We anticipate finding relevant literature on the dynamics of HIV transmission in South African men. Once summarized, data will be useful to guide future research. PROSPERO CRD42016039489.

  5. Multidrug-resistant and extensively drug-resistant tuberculosis: implications for the HIV epidemic and antiretroviral therapy rollout in South Africa.

    Science.gov (United States)

    Andrews, Jason R; Shah, N Sarita; Gandhi, Neel; Moll, Tony; Friedland, Gerald

    2007-12-01

    Drug-resistant tuberculosis (TB) is emerging as a major clinical and public health challenge in areas of sub-Saharan Africa where there is a high prevalence of human immunodeficiency virus (HIV) infection. TB drug-resistance surveillance in this region has been limited by laboratory capacity and the public health infrastructure; however, with the maturation of the HIV epidemic, the burden of drug-resistant TB is increasing rapidly. The recent discovery of large numbers of cases of multidrug-resistant (MDR) TB and extensively drug-resistant (XDR) TB in South Africa likely represents an unrecognized and evolving epidemic rather than sporadic, localized outbreaks. The combination of a large population of HIV-infected susceptible hosts with poor TB treatment success rates, a lack of airborne infection control, limited drug-resistance testing, and an overburdened MDR-TB treatment program provides ideal conditions for an MDR-TB and XDR-TB epidemic of unparalleled magnitude. In the present article, we review the history of drug-resistant TB in South Africa, describe its interaction with the HIV epidemic and the resultant consequences, and suggest measures necessary for controlling MDR-TB and XDR-TB in this context. A successful response to the emergence of MDR-TB and XDR-TB will necessitate increased resources for and collaboration between TB and HIV programs.

  6. ¿Hacia dónde se encamina la epidemia de infección por VIH y sida? HIV and AIDS: where is the epidemic going?

    Directory of Open Access Journals (Sweden)

    T. E. Mertens

    1997-03-01

    pregnant women in southern Zaire and parts of Uganda, among military recruits aged 21 in Thailand, and in some populations of northern Europe and the USA. While these changes may take place as part of the intrinsic dynamic of the epidemic, there is some evidence that declines in HIV prevalence are related to declines in HIV incidence which are, at least partly, due to prevention efforts. The challenge of surveillance and evaluation methods is now to identify the ingredients of success which may reveal a glimmer of hope.

  7. Brief behavioural surveys in routine HIV sentinel surveillance: a new tool for monitoring the HIV epidemic in Viet Nam

    Directory of Open Access Journals (Sweden)

    Duong Cong Thanh

    2015-01-01

    Full Text Available In this report we describe a new approach in HIV sentinel surveillance that was piloted in Viet Nam in 2009 and is currently being rolled out in all provinces. It comprises a brief behavioural questionnaire added to the HIV sentinel surveillance surveys conducted routinely among people who inject drugs, female sex workers and men who have sex with men. Timely reporting of data from this system has resulted in improvements to HIV prevention efforts for most at-risk populations.

  8. Brief behavioural surveys in routine HIV sentinel surveillance: a new tool for monitoring the HIV epidemic in Viet Nam.

    Science.gov (United States)

    Thanh, Duong Cong; Hien, Nguyen Tran; Tuan, Nguyen Anh; Ha, Hoang Thi Thanh; Thang, Pham Hong; Ha, Nguyen Thi Thanh; Tuan, Le Anh; Quang, Tran Dai; Tram, Tran Hong; Le Hai, Nguyen; Huong, Phan Thi Thu; Son, Vo Hai; Duc, Bui Hoang; Nga, Nguyen Thien; Jacka, David; Sabin, Keith

    2015-01-01

    In this report we describe a new approach in HIV sentinel surveillance that was piloted in Viet Nam in 2009 and is currently being rolled out in all provinces. It comprises a brief behavioural questionnaire added to the HIV sentinel surveillance surveys conducted routinely among people who inject drugs, female sex workers and men who have sex with men. Timely reporting of data from this system has resulted in improvements to HIV prevention efforts for most at-risk populations.

  9. Bursty communication patterns facilitate spreading in a threshold-based epidemic dynamics.

    Science.gov (United States)

    Takaguchi, Taro; Masuda, Naoki; Holme, Petter

    2013-01-01

    Records of social interactions provide us with new sources of data for understanding how interaction patterns affect collective dynamics. Such human activity patterns are often bursty, i.e., they consist of short periods of intense activity followed by long periods of silence. This burstiness has been shown to affect spreading phenomena; it accelerates epidemic spreading in some cases and slows it down in other cases. We investigate a model of history-dependent contagion. In our model, repeated interactions between susceptible and infected individuals in a short period of time is needed for a susceptible individual to contract infection. We carry out numerical simulations on real temporal network data to find that bursty activity patterns facilitate epidemic spreading in our model.

  10. Dynamics of epidemic spreading model with drug-resistant variation on scale-free networks

    Science.gov (United States)

    Wan, Chen; Li, Tao; Zhang, Wu; Dong, Jing

    2018-03-01

    Considering the influence of the virus' drug-resistant variation, a novel SIVRS (susceptible-infected-variant-recovered-susceptible) epidemic spreading model with variation characteristic on scale-free networks is proposed in this paper. By using the mean-field theory, the spreading dynamics of the model is analyzed in detail. Then, the basic reproductive number R0 and equilibriums are derived. Studies show that the existence of disease-free equilibrium is determined by the basic reproductive number R0. The relationships between the basic reproductive number R0, the variation characteristic and the topology of the underlying networks are studied in detail. Furthermore, our studies prove the global stability of the disease-free equilibrium, the permanence of epidemic and the global attractivity of endemic equilibrium. Numerical simulations are performed to confirm the analytical results.

  11. Bursty communication patterns facilitate spreading in a threshold-based epidemic dynamics.

    Directory of Open Access Journals (Sweden)

    Taro Takaguchi

    Full Text Available Records of social interactions provide us with new sources of data for understanding how interaction patterns affect collective dynamics. Such human activity patterns are often bursty, i.e., they consist of short periods of intense activity followed by long periods of silence. This burstiness has been shown to affect spreading phenomena; it accelerates epidemic spreading in some cases and slows it down in other cases. We investigate a model of history-dependent contagion. In our model, repeated interactions between susceptible and infected individuals in a short period of time is needed for a susceptible individual to contract infection. We carry out numerical simulations on real temporal network data to find that bursty activity patterns facilitate epidemic spreading in our model.

  12. HIV/AIDS among inmates of and releasees from US correctional facilities, 2006: declining share of epidemic but persistent public health opportunity.

    Directory of Open Access Journals (Sweden)

    Anne C Spaulding

    2009-11-01

    Full Text Available Because certain groups at high risk for HIV/AIDS (human immunodeficiency virus/acquired immunodeficiency syndrome come together in correctional facilities, seroprevalence was high early in the epidemic. The share of the HIV/AIDS epidemic borne by inmates of and persons released from jails and prisons in the United States (US in 1997 was estimated in a previous paper. While the number of inmates and releasees has risen, their HIV seroprevalence rates have fallen. We sought to determine if the share of HIV/AIDS borne by inmates and releasees in the US decreased between 1997 and 2006. We created a new model of population flow in and out of correctional facilities to estimate the number of persons released in 1997 and 2006. In 1997, approximately one in five of all HIV-infected Americans was among the 7.3 million who left a correctional facility that year. Nine years later, only one in seven (14% of infected Americans was among the 9.1 million leaving, a 29.3% decline in the share. For black and Hispanic males, two demographic groups with heightened incarceration rates, recently released inmates comprise roughly one in five of those groups' total HIV-infected persons, a figure similar to the proportion borne by the correctional population as a whole in 1997. Decreasing HIV seroprevalence among those admitted to jails and prisons, prolonged survival and aging of the US population with HIV/AIDS beyond the crime-prone years, and success with discharge planning programs targeting HIV-infected prisoners could explain the declining concentration of the epidemic among correctional populations. Meanwhile, the number of persons with HIV/AIDS leaving correctional facilities remains virtually identical. Jails and prisons continue to be potent targets for public health interventions. The fluid nature of incarcerated populations ensures that effective interventions will be felt not only in correctional facilities but also in communities to which releasees return.

  13. HIV/AIDS among inmates of and releasees from US correctional facilities, 2006: declining share of epidemic but persistent public health opportunity.

    Science.gov (United States)

    Spaulding, Anne C; Seals, Ryan M; Page, Matthew J; Brzozowski, Amanda K; Rhodes, William; Hammett, Theodore M

    2009-11-11

    Because certain groups at high risk for HIV/AIDS (human immunodeficiency virus/acquired immunodeficiency syndrome) come together in correctional facilities, seroprevalence was high early in the epidemic. The share of the HIV/AIDS epidemic borne by inmates of and persons released from jails and prisons in the United States (US) in 1997 was estimated in a previous paper. While the number of inmates and releasees has risen, their HIV seroprevalence rates have fallen. We sought to determine if the share of HIV/AIDS borne by inmates and releasees in the US decreased between 1997 and 2006. We created a new model of population flow in and out of correctional facilities to estimate the number of persons released in 1997 and 2006. In 1997, approximately one in five of all HIV-infected Americans was among the 7.3 million who left a correctional facility that year. Nine years later, only one in seven (14%) of infected Americans was among the 9.1 million leaving, a 29.3% decline in the share. For black and Hispanic males, two demographic groups with heightened incarceration rates, recently released inmates comprise roughly one in five of those groups' total HIV-infected persons, a figure similar to the proportion borne by the correctional population as a whole in 1997. Decreasing HIV seroprevalence among those admitted to jails and prisons, prolonged survival and aging of the US population with HIV/AIDS beyond the crime-prone years, and success with discharge planning programs targeting HIV-infected prisoners could explain the declining concentration of the epidemic among correctional populations. Meanwhile, the number of persons with HIV/AIDS leaving correctional facilities remains virtually identical. Jails and prisons continue to be potent targets for public health interventions. The fluid nature of incarcerated populations ensures that effective interventions will be felt not only in correctional facilities but also in communities to which releasees return.

  14. Assessing the HIV-1 Epidemic in Brazilian Drug Users: A Molecular Epidemiology Approach.

    Directory of Open Access Journals (Sweden)

    Monick Lindenmeyer Guimarães

    Full Text Available Person who inject illicit substances have an important role in HIV-1 blood and sexual transmission and together with person who uses heavy non-injecting drugs may have less than optimal adherence to anti-retroviral treatment and eventually could transmit resistant HIV variants. Unfortunately, molecular biology data on such key population remain fragmentary in most low and middle-income countries. The aim of the present study was to assess HIV infection rates, evaluate HIV-1 genetic diversity, drug resistance, and to identify HIV transmission clusters in heavy drug users (DUs. For this purpose, DUs were recruited in the context of a Respondent-Driven Sampling (RDS study in different Brazilian cities during 2009. Overall, 2,812 individuals were tested for HIV, and 168 (6% of them were positive, of which 19 (11.3% were classified as recent seroconverters, corresponding to an estimated incidence rate of 1.58%/year (95% CI 0.92-2.43%. Neighbor joining phylogenetic trees from env and pol regions and bootscan analyses were employed to subtype the virus from132 HIV-1-infected individuals. HIV-1 subtype B was prevalent in most of the cities under analysis, followed by BF recombinants (9%-35%. HIV-1 subtype C was the most prevalent in Curitiba (46% and Itajaí (86% and was also detected in Brasília (9% and Campo Grande (20%. Pure HIV-1F infections were detected in Rio de Janeiro (9%, Recife (6%, Salvador (6% and Brasília (9%. Clusters of HIV transmission were assessed by Maximum likelihood analyses and were cross-compared with the RDS network structure. Drug resistance mutations were verified in 12.2% of DUs. Our findings reinforce the importance of the permanent HIV-1 surveillance in distinct Brazilian cities due to viral resistance and increasing subtype heterogeneity all over Brazil, with relevant implications in terms of treatment monitoring, prophylaxis and vaccine development.

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

    Science.gov (United States)

    Eggo, Rosalind M; Lenczner, Michael

    2015-01-01

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

  16. The Prevalence of HIV/AIDS Epidemic in Anambra State, Nigeria ...

    African Journals Online (AJOL)

    In 2012 AVERT'S HIV/AIDS statistics records Nigeria as the second largest number ... state, Nigeria with 8.7% above the national prevalence average rate of 4.5 per cent. ... Results revealed among others that: biological issues, poverty, female ... false religious assurances against HIV/AIDS, and traditional birth practices are ...

  17. HIV epidemic drivers in South Africa: A model-based evaluation of ...

    African Journals Online (AJOL)

    Background: HIV prevalence differs substantially between South Africa's provinces, but the factors accounting for this difference are poorly understood. Objectives: To estimate HIV prevalence and incidence trends by province, and to identify the epidemiological factors that account for most of the variation between provinces ...

  18. Agent-based financial dynamics model from stochastic interacting epidemic system and complexity analysis

    International Nuclear Information System (INIS)

    Lu, Yunfan; Wang, Jun; Niu, Hongli

    2015-01-01

    An agent-based financial stock price model is developed and investigated by a stochastic interacting epidemic system, which is one of the statistical physics systems and has been used to model the spread of an epidemic or a forest fire. Numerical and statistical analysis are performed on the simulated returns of the proposed financial model. Complexity properties of the financial time series are explored by calculating the correlation dimension and using the modified multiscale entropy method. In order to verify the rationality of the financial model, the real stock market indexes, Shanghai Composite Index and Shenzhen Component Index, are studied in comparison with the simulation data of the proposed model for the different infectiousness parameters. The empirical research reveals that this financial model can reproduce some important features of the real stock markets. - Highlights: • A new agent-based financial price model is developed by stochastic interacting epidemic system. • The structure of the proposed model allows to simulate the financial dynamics. • Correlation dimension and MMSE are applied to complexity analysis of financial time series. • Empirical results show the rationality of the proposed financial model

  19. Agent-based financial dynamics model from stochastic interacting epidemic system and complexity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yunfan, E-mail: yunfanlu@yeah.net; Wang, Jun; Niu, Hongli

    2015-06-12

    An agent-based financial stock price model is developed and investigated by a stochastic interacting epidemic system, which is one of the statistical physics systems and has been used to model the spread of an epidemic or a forest fire. Numerical and statistical analysis are performed on the simulated returns of the proposed financial model. Complexity properties of the financial time series are explored by calculating the correlation dimension and using the modified multiscale entropy method. In order to verify the rationality of the financial model, the real stock market indexes, Shanghai Composite Index and Shenzhen Component Index, are studied in comparison with the simulation data of the proposed model for the different infectiousness parameters. The empirical research reveals that this financial model can reproduce some important features of the real stock markets. - Highlights: • A new agent-based financial price model is developed by stochastic interacting epidemic system. • The structure of the proposed model allows to simulate the financial dynamics. • Correlation dimension and MMSE are applied to complexity analysis of financial time series. • Empirical results show the rationality of the proposed financial model.

  20. Modelling HIV/AIDS Epidemic among Men Who Have Sex with Men in China

    Directory of Open Access Journals (Sweden)

    Xiaodan Sun

    2013-01-01

    a higher transmission rate and a lower diagnose rate among MSM than those for another high-risk population. We compared the current treatment policy and immediate therapy once people are diagnosed with HIV, and numerical studies indicated that immediate antiviral therapy would lead to few HIV new infections conditional upon relatively low infectiousness; otherwise the current treatment policy would result in low HIV new infection. Further, increasing treatment coverage rate may lead to decline in HIV new infections and be beneficial to disease control, depending on the infectiousness of the infected individuals with antiviral therapy. The finding suggested that treatment efficacy (directly affecting infectiousness, behavior changes, and interventions greatly affect HIV new infection; strengthening intensity will contribute to the disease control.

  1. Dynamics of a stochastic delayed SIR epidemic model with vaccination and double diseases driven by Lévy jumps

    Science.gov (United States)

    Liu, Qun; Jiang, Daqing; Shi, Ningzhong; Hayat, Tasawar

    2018-02-01

    In this paper, we study the dynamics of a stochastic delayed SIR epidemic model with vaccination and double diseases which make the research more complex. The environment variability in this paper is characterized by white noise and Lévy noise. We establish sufficient conditions for extinction and persistence in the mean of the two epidemic diseases. It is shown that: (i) time delay and Lévy noise have important effects on the persistence and extinction of epidemic diseases; (ii) two diseases can coexist under certain conditions.

  2. HIV Infection in Migrant Populations in the European Union and European Economic Area in 2007-2012: An Epidemic on the Move.

    Science.gov (United States)

    Hernando, Victoria; Alvárez-del Arco, Débora; Alejos, Belén; Monge, Susana; Amato-Gauci, Andrew J; Noori, Teymur; Pharris, Anastasia; del Amo, Julia

    2015-10-01

    Migrants are considered a key group at risk for HIV infection. This study describes the epidemiology of HIV and the distribution of late HIV presentation among migrants within the European Union/European Economic Area during 2007-2012. HIV cases reported to European Surveillance System (TESSy) were analyzed. Migrants were defined as people whose geographical origin was different than the reporting country. Multiple logistic regression was used to model late HIV presentation. Overall, 156,817 HIV cases were reported, of which 60,446 (38%) were migrants. Of these, 53% were from Sub-Saharan Africa, 12% from Latin America, 9% from Western Europe, 7% from Central Europe, 5% from South and Southeast Asia, 4% from East Europe, 4% from Caribbean, and 3% from North Africa and Middle East. Male and female migrants from Sub-Saharan Africa and Latin America had higher odds of late HIV presentation than native men and women. Migrants accounted for 40% of all HIV notifications in 2007 versus 35% in 2012. HIV cases in women from Sub-Saharan Africa decreased from 3725 in 2007 to 2354 in 2012. The number of HIV cases from Latin America peaked in 2010 to decrease thereafter. HIV diagnoses in migrant men who have sex with men increased from 1927 in 2007 to 2459 in 2012. Migrants represent two-fifths of the HIV cases reported and had higher late HIV presentation. HIV epidemic in migrant populations in European Union/European Economic Area member states is changing, probably reflecting the global changes in the HIV pandemic, the impact of large-scale ART implementation, and migration fluctuations secondary to the economic crisis in Europe.

  3. Religion, spirituality, and older adults with HIV: critical personal and social resources for an aging epidemic

    Directory of Open Access Journals (Sweden)

    Vance D

    2011-05-01

    Full Text Available David E Vance1, Mark Brennan2, Comfort Enah1, Glenda L Smith1, Jaspreet Kaur31School of Nursing, University of Alabama at Birmingham (UAB, Birmingham, AL, USA; 2New York University College of Nursing, AIDS Community Research Initiative of America, New York, NY, USA; 3Department of Psychology and Edward R. Roybal Center for Translational Research in Aging and Mobility, University of Alabama at Birmingham (UAB, Birmingham, AL, USAAbstract: By 2015, approximately half of adults with HIV in the United States will be 50 and older. The demographic changes in this population due to successful treatment represent a unique challenge, not only in assisting these individuals to cope with their illness, but also in helping them to age successfully with this disease. Religious involvement and spirituality have been observed to promote successful aging in the general population and help those with HIV cope with their disease, yet little is known about how these resources may affect aging with HIV. Also, inherent barriers such as HIV stigma and ageism may prevent people from benefitting from religious and spiritual sources of solace as they age with HIV. In this paper, we present a model of barriers to successful aging with HIV, along with a discussion of how spirituality and religiousness may help people overcome these barriers. From this synthesis, implications for practice and research to improve the quality of life of this aging population are provided.Keywords: HIV, aging, spirituality, religion, stigma, coping, successful aging

  4. The role of international migration in infectious diseases: the HIV epidemic and its trends in Japan.

    Science.gov (United States)

    Komatsu, Ryuichi; Sawada, Takashi

    2007-01-01

    Globalization and its associated international migrations facilitate the spread of infectious diseases. This article reports trends in and discusses the relation between international migration and HIV infection in Japan. The authors analyze relevant literature, drawing on government and other sources. Among foreigners in Japan, there were 27.0 reported HIV and 9.3 reported AIDS cases per million in 1990, and 52.9 HIV and 38.8 AIDS cases per million in 2000. These rates were initially 45 to 90 times the population prevalence of HIV and AIDS among Japanese, but are now only 10 to 20 times the prevalence among Japanese, as HIV becomes an increasing problem for the Japanese population. HIV-infected foreigners who are uninsured are at a disadvantage for diagnosis, counseling, and treatment compared with insured persons, and at a significantly higher risk for low CD4 counts. For all sections of Japan's population, counseling and testing are inadequate, and surveillance of behavioral risk, infection, and disease is limited. International migrants are at increased risk for HIV transmission and at a disadvantage for care and treatment. Japan needs both to develop policies that assist migrants and to respond to the growing threat among its nonmigrant population.

  5. The importance of including dynamic social networks when modeling epidemics of airborne infections: does increasing complexity increase accuracy?

    OpenAIRE

    Blower, Sally; Go, Myong-Hyun

    2011-01-01

    Abstract Mathematical models are useful tools for understanding and predicting epidemics. A recent innovative modeling study by Stehle and colleagues addressed the issue of how complex models need to be to ensure accuracy. The authors collected data on face-to-face contacts during a two-day conference. They then constructed a series of dynamic social contact networks, each of which was used to model an epidemic generated by a fast-spreading airborne pathogen. Intriguingly, Stehle and colleagu...

  6. Trends in risk behaviors among female sex workers in south India: priorities for sustaining the reversal of HIV epidemic.

    Science.gov (United States)

    Charles, Bimal; Jeyaseelan, Lakshmanan; Edwin Sam, Asirvatham; Kumar Pandian, Arvind; Thenmozhi, Mani; Jeyaseelan, Visalakshi

    2013-01-01

    HIV epidemic in India is predominantly concentrated in subgroups of population, such as female sex workers (FSWs) and their clients, whose behavior exposes them to a higher risk of acquiring HIV infection. This paper aims to present the changing patterns of socio-demographic characteristics, behaviors, reported sexually transmitted infections (STIs), and associated factors among FSWs over 11 years. Multistage cluster sampling with probability-proportional-to-size (PPS) method was used in the surveys. A sample of 400 FSWs was studied every year. The mean age and literacy at the baseline level increased significantly over the years. House-based sex increased by 40% from 43.3% in 1997 to 83% in 2008 (p<0.001). Condom use at last sex with one-time clients; consistent condom use (CCU) with one-time and regular clients indicated increasing trends. FSWs reported low levels of condom use at last sex (14.5% in 1997 to 5% in 2008; p<0.001) and CCU (12.6% in 2004 to 3.6% in 2008; p<0.01) with regular partners. FSWs who used condom with one-time clients at last sex reported significantly less STI symptoms. A two-third reduction in genital ulcers was found from 13.1% in 1997 to 4.5% in 2008 (p<0.001). Nonliterate and hotel-based sex workers were 1.6 (1.0-2.5; 95% CI) and 2.2(1.3-3.7; 95% CI) times more likely to have reported STI symptoms. The percentage of FSWs who underwent HIV testing increased (p<0.001); similarly, a 20% increase was found in FSWs who availed counseling services from 65.2% in 1997 to 85.4% in 2008 (p<0.001). Poor, illiterate, and marginalized were more likely to get involved in risky behaviors which suggest the need for structural interventions as part of HIV prevention strategy.

  7. Public health triangulation: approach and application to synthesizing data to understand national and local HIV epidemics

    Directory of Open Access Journals (Sweden)

    Aberle-Grasse John

    2010-07-01

    Full Text Available Abstract Background Public health triangulation is a process for reviewing, synthesising and interpreting secondary data from multiple sources that bear on the same question to make public health decisions. It can be used to understand the dynamics of HIV transmission and to measure the impact of public health programs. While traditional intervention research and metaanalysis would be ideal sources of information for public health decision making, they are infrequently available, and often decisions can be based only on surveillance and survey data. Methods The process involves examination of a wide variety of data sources and both biological, behavioral and program data and seeks input from stakeholders to formulate meaningful public health questions. Finally and most importantly, it uses the results to inform public health decision-making. There are 12 discrete steps in the triangulation process, which included identification and assessment of key questions, identification of data sources, refining questions, gathering data and reports, assessing the quality of those data and reports, formulating hypotheses to explain trends in the data, corroborating or refining working hypotheses, drawing conclusions, communicating results and recommendations and taking public health action. Results Triangulation can be limited by the quality of the original data, the potentials for ecological fallacy and "data dredging" and reproducibility of results. Conclusions Nonetheless, we believe that public health triangulation allows for the interpretation of data sets that cannot be analyzed using meta-analysis and can be a helpful adjunct to surveillance, to formal public health intervention research and to monitoring and evaluation, which in turn lead to improved national strategic planning and resource allocation.

  8. What's to be done? Report on a bosberaad to discuss the HIV epidemic in South Africa

    CSIR Research Space (South Africa)

    Williams, BG

    2000-06-01

    Full Text Available Demographic forecasting models of the South African population, incorporating geographical distribution and age prevalence data on HIV infection, have been used to predict future mortality due to AIDS. In year 2010, approximately 500 000 AIDS...

  9. Has the HIV epidemic in rural Mwanza, Tanzania reached a plateau?

    African Journals Online (AJOL)

    migration of HIV positive people out of the communities or when ... rural Mwanza may be responsible for changes in risky sexual behaviour and have successfully impeded the spread ... 20 clusters and cluster sampling was used to select 7-9.

  10. the protective role of schooling in the HIV epidemic in Swaziland

    African Journals Online (AJOL)

    While HIV prevalence rises rapidly among young women in Swaziland, as is the case across most of ... was available, this was the “best practice” for collecting .... Empowerment is critical for reducing all forms of GBV. ... enter the workforce.

  11. Engineering behaviour change in an epidemic: the epistemology of NIH-funded HIV prevention science.

    Science.gov (United States)

    Green, Adam; Kolar, Kat

    2015-05-01

    Social scientific and public health literature on National Institutes of Health-funded HIV behavioural prevention science often assumes that this body of work has a strong biomedical epistemological orientation. We explore this assumption by conducting a systematic content analysis of all NIH-funded HIV behavioural prevention grants for men who have sex with men between 1989 and 2012. We find that while intervention research strongly favours a biomedical orientation, research into the antecedents of HIV risk practices favours a sociological, interpretive and structural orientation. Thus, with respect to NIH-funded HIV prevention science, there exists a major disjunct in the guiding epistemological orientations of how scientists understand HIV risk, on the one hand, and how they engineer behaviour change in behavioural interventions, on the other. Building on the extant literature, we suggest that the cause of this disjunct is probably attributable not to an NIH-wide positivist orientation, but to the specific standards of evidence used to adjudicate HIV intervention grant awards, including randomised controlled trials and other quantitative measures of intervention efficacy. © 2015 The Authors. Sociology of Health & Illness © 2015 Foundation for the Sociology of Health & Illness/John Wiley & Sons Ltd.

  12. Profile of the HIV epidemic in Cape Verde: molecular epidemiology and drug resistance mutations among HIV-1 and HIV-2 infected patients from distinct islands of the archipelago.

    Science.gov (United States)

    de Pina-Araujo, Isabel Inês M; Guimarães, Monick L; Bello, Gonzalo; Vicente, Ana Carolina P; Morgado, Mariza G

    2014-01-01

    HIV-1 and HIV-2 have been detected in Cape Verde since 1987, but little is known regarding the genetic diversity of these viruses in this archipelago, located near the West African coast. In this study, we characterized the molecular epidemiology of HIV-1 and HIV-2 and described the occurrence of drug resistance mutations (DRM) among antiretroviral therapy naïve (ARTn) patients and patients under treatment (ARTexp) from different Cape Verde islands. Blood samples, socio-demographic and clinical-laboratory data were obtained from 221 HIV-positive individuals during 2010-2011. Phylogenetic and bootscan analyses of the pol region (1300 bp) were performed for viral subtyping. HIV-1 and HIV-2 DRM were evaluated for ARTn and ARTexp patients using the Stanford HIV Database and HIV-GRADE e.V. Algorithm Homepage, respectively. Among the 221 patients (169 [76.5%] HIV-1, 43 [19.5%] HIV-2 and 9 [4.1%] HIV-1/HIV-2 co-infections), 67% were female. The median ages were 34 (IQR = 1-75) and 47 (IQR = 12-84) for HIV-1 and HIV-2, respectively. HIV-1 infections were due to subtypes G (36.6%), CRF02_AG (30.6%), F1 (9.7%), URFs (10.4%), B (5.2%), CRF05_DF (3.0%), C (2.2%), CRF06_cpx (0.7%), CRF25_cpx (0.7%) and CRF49_cpx (0.7%), whereas all HIV-2 infections belonged to group A. Transmitted DRM (TDRM) was observed in 3.4% (2/58) of ARTn HIV-1-infected patients (1.7% NRTI, 1.7% NNRTI), but not among those with HIV-2. Among ARTexp patients, DRM was observed in 47.8% (33/69) of HIV-1 (37.7% NRTI, 37.7% NNRTI, 7.4% PI, 33.3% for two classes) and 17.6% (3/17) of HIV-2-infections (17.6% NRTI, 11.8% PI, 11.8% both). This study indicates that Cape Verde has a complex and unique HIV-1 molecular epidemiological scenario dominated by HIV-1 subtypes G, CRF02_AG and F1 and HIV-2 subtype A. The occurrence of TDRM and the relatively high level of DRM among treated patients are of concern. Continuous monitoring of patients on ART, including genotyping, are public policies to be implemented.

  13. Looking upstream to prevent HIV transmission: can interventions with sex workers alter the course of HIV epidemics in Africa as they did in Asia?

    NARCIS (Netherlands)

    Steen, R. van der; Hontelez, J.A.; Veraart, A.; White, R.G.; Vlas, S.J. de

    2014-01-01

    BACKGROUND: High rates of partner change in 'upstream' sex work networks have long been recognized to drive 'downstream' transmission of sexually transmitted infections (STIs). We used a stochastic microsimulation model (STDSIM) to explore such transmission dynamics in a generalized African HIV

  14. Effect of vaccination strategies on the dynamic behavior of epidemic spreading and vaccine coverage

    International Nuclear Information System (INIS)

    Cai, Chao-Ran; Wu, Zhi-Xi; Guan, Jian-Yue

    2014-01-01

    The transmission of infectious, yet vaccine-preventable, diseases is a typical complex social phenomenon, where the increasing level of vaccine update in the population helps to inhibit the epidemic spreading, which in turn, however, discourages more people to participate in vaccination campaigns, due to the “externality effect” raised by vaccination. We herein study the impact of vaccination strategies, pure, continuous (rather than adopt vaccination definitely, the individuals choose to taking vaccine with some probabilities), or continuous with randomly mutation, on the vaccination dynamics with a spatial susceptible-vaccinated-infected-recovered (SVIR) epidemiological model. By means of extensive Monte-Carlo simulations, we show that there is a crossover behavior of the final vaccine coverage between the pure-strategy case and the continuous-strategy case, and remarkably, both the final vaccination level and epidemic size in the continuous-strategy case are less than them in the pure-strategy case when vaccination is cheap. We explain this phenomenon by analyzing the organization process of the individuals in the continuous-strategy case in the equilibrium. Our results are robust to the SVIR dynamics defined on other spatial networks, like the Erdős–Rényi and Barabási–Albert networks

  15. Time Prediction Models for Echinococcosis Based on Gray System Theory and Epidemic Dynamics.

    Science.gov (United States)

    Zhang, Liping; Wang, Li; Zheng, Yanling; Wang, Kai; Zhang, Xueliang; Zheng, Yujian

    2017-03-04

    Echinococcosis, which can seriously harm human health and animal husbandry production, has become an endemic in the Xinjiang Uygur Autonomous Region of China. In order to explore an effective human Echinococcosis forecasting model in Xinjiang, three grey models, namely, the traditional grey GM(1,1) model, the Grey-Periodic Extensional Combinatorial Model (PECGM(1,1)), and the Modified Grey Model using Fourier Series (FGM(1,1)), in addition to a multiplicative seasonal ARIMA(1,0,1)(1,1,0)₄ model, are applied in this study for short-term predictions. The accuracy of the different grey models is also investigated. The simulation results show that the FGM(1,1) model has a higher performance ability, not only for model fitting, but also for forecasting. Furthermore, considering the stability and the modeling precision in the long run, a dynamic epidemic prediction model based on the transmission mechanism of Echinococcosis is also established for long-term predictions. Results demonstrate that the dynamic epidemic prediction model is capable of identifying the future tendency. The number of human Echinococcosis cases will increase steadily over the next 25 years, reaching a peak of about 1250 cases, before eventually witnessing a slow decline, until it finally ends.

  16. Time Prediction Models for Echinococcosis Based on Gray System Theory and Epidemic Dynamics

    Directory of Open Access Journals (Sweden)

    Liping Zhang

    2017-03-01

    Full Text Available Echinococcosis, which can seriously harm human health and animal husbandry production, has become an endemic in the Xinjiang Uygur Autonomous Region of China. In order to explore an effective human Echinococcosis forecasting model in Xinjiang, three grey models, namely, the traditional grey GM(1,1 model, the Grey-Periodic Extensional Combinatorial Model (PECGM(1,1, and the Modified Grey Model using Fourier Series (FGM(1,1, in addition to a multiplicative seasonal ARIMA(1,0,1(1,1,04 model, are applied in this study for short-term predictions. The accuracy of the different grey models is also investigated. The simulation results show that the FGM(1,1 model has a higher performance ability, not only for model fitting, but also for forecasting. Furthermore, considering the stability and the modeling precision in the long run, a dynamic epidemic prediction model based on the transmission mechanism of Echinococcosis is also established for long-term predictions. Results demonstrate that the dynamic epidemic prediction model is capable of identifying the future tendency. The number of human Echinococcosis cases will increase steadily over the next 25 years, reaching a peak of about 1250 cases, before eventually witnessing a slow decline, until it finally ends.

  17. HIV incidence in Asia: a review of available data and assessment of the epidemic.

    Science.gov (United States)

    Dokubo, E Kainne; Kim, Andrea A; Le, Linh-Vi; Nadol, Patrick J; Prybylski, Dimitri; Wolfe, Mitchell I

    2013-01-01

    Rates of new HIV infections in Asia are poorly characterized, likely resulting in knowledge gaps about infection trends and the most important areas to target for interventions. We conducted a systematic review of peer-reviewed English language publications and conference abstracts on HIV incidence in thirteen countries - Bangladesh, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, Taiwan, Thailand, and Vietnam. We obtained data on HIV incidence rate, incidence estimation method, population, and risk factors for incident infection. Our search yielded 338 unique incidence estimates from 70 published articles and 41 conference abstracts for eight countries. A total of 138 (41%) were obtained from prospective cohort studies and 106 (31%) were from antibody-based tests for recent infection. High HIV incidence rates were observed among commercial sex workers (0.4-27.8 per 100 person-years), people who inject drugs (0.0-43.6 per 100 person-years) and men who have sex with men (0.7-15.0 per 100 person-years). Risk factors for incident HIV infection include brothel-based sex work and cervicitis among commercial sex workers; young age, frequent injection use and sharing needles or syringes among people who inject drugs; multiple male sexual partners, receptive anal intercourse and syphilis infection among men who have sex with men. In the countries with available data, incidence rates were highest in key populations and varied widely by incidence estimation method. Established surveillance systems that routinely monitor trends in HIV incidence are needed to inform prevention planning, prioritize resources, measure impact, and improve the HIV response in Asia.

  18. Re-thinking global health sector efforts for HIV and tuberculosis epidemic control: promoting integration of programme activities within a strengthened health system.

    Science.gov (United States)

    Maher, Dermot

    2010-07-05

    The global financial crisis threatens global health, particularly exacerbating diseases of inequality, e.g. HIV/AIDS, and diseases of poverty, e.g. tuberculosis. The aim of this paper is to reconsider established practices and policies for HIV and tuberculosis epidemic control, aiming at delivering better results and value for money. This may be achieved by promoting greater integration of HIV and tuberculosis control programme activities within a strengthened health system. HIV and tuberculosis share many similarities in terms of their disease burden and the recommended stratagems for their control. HIV and tuberculosis programmes implement similar sorts of control activities, e.g. case finding and treatment, which depend for success on generic health system issues, including vital registration, drug procurement and supply, laboratory network, human resources, and financing. However, the current health system approach to HIV and tuberculosis control often involves separate specialised services. Despite some recent progress, collaboration between the programmes remains inadequate, progress in obtaining synergies has been slow, and results remain far below those needed to achieve universal access to key interventions. A fundamental re-think of the current strategic approach involves promoting integrated delivery of HIV and tuberculosis programme activities as part of strengthened general health services: epidemiological surveillance, programme monitoring and evaluation, community awareness of health-seeking behavior, risk behaviour modification, infection control, treatment scale-up (first-line treatment regimens), drug-resistance surveillance, containing and countering drug-resistance (second-line treatment regimens), research and development, global advocacy and global partnership. Health agencies should review policies and progress in HIV and tuberculosis epidemic control, learn mutual lessons for policy development and scaling up interventions, and identify ways

  19. Re-thinking global health sector efforts for HIV and tuberculosis epidemic control: promoting integration of programme activities within a strengthened health system

    Directory of Open Access Journals (Sweden)

    Maher Dermot

    2010-07-01

    Full Text Available Abstract Background The global financial crisis threatens global health, particularly exacerbating diseases of inequality, e.g. HIV/AIDS, and diseases of poverty, e.g. tuberculosis. The aim of this paper is to reconsider established practices and policies for HIV and tuberculosis epidemic control, aiming at delivering better results and value for money. This may be achieved by promoting greater integration of HIV and tuberculosis control programme activities within a strengthened health system. Discussion HIV and tuberculosis share many similarities in terms of their disease burden and the recommended stratagems for their control. HIV and tuberculosis programmes implement similar sorts of control activities, e.g. case finding and treatment, which depend for success on generic health system issues, including vital registration, drug procurement and supply, laboratory network, human resources, and financing. However, the current health system approach to HIV and tuberculosis control often involves separate specialised services. Despite some recent progress, collaboration between the programmes remains inadequate, progress in obtaining synergies has been slow, and results remain far below those needed to achieve universal access to key interventions. A fundamental re-think of the current strategic approach involves promoting integrated delivery of HIV and tuberculosis programme activities as part of strengthened general health services: epidemiological surveillance, programme monitoring and evaluation, community awareness of health-seeking behavior, risk behaviour modification, infection control, treatment scale-up (first-line treatment regimens, drug-resistance surveillance, containing and countering drug-resistance (second-line treatment regimens, research and development, global advocacy and global partnership. Health agencies should review policies and progress in HIV and tuberculosis epidemic control, learn mutual lessons for policy

  20. Threshold dynamics and ergodicity of an SIRS epidemic model with Markovian switching

    Science.gov (United States)

    Li, Dan; Liu, Shengqiang; Cui, Jing'an

    2017-12-01

    This paper studies the spread dynamics of a stochastic SIRS epidemic model with nonlinear incidence and varying population size, which is formulated as a piecewise deterministic Markov process. A threshold dynamic determined by the basic reproduction number R0 is established: the disease can be eradicated almost surely if R0 disease persists almost surely if R0 > 1. The existing method for analyzing ergodic behavior of population systems has been generalized. The modified method weakens the required conditions and has no limitations for both the number of environmental regimes and the dimension of the considered system. When R0 > 1, the existence of a stationary probability measure is obtained. Furthermore, with the modified method, the global attractivity of the Ω-limit set of the system and the convergence in total variation to the stationary measure are both demonstrated under a mild extra condition.

  1. HIV/AIDS prevention, faith, and spirituality among black/African American and Latino communities in the United States: strengthening scientific faith-based efforts to shift the course of the epidemic and reduce HIV-related health disparities.

    Science.gov (United States)

    Sutton, Madeline Y; Parks, Carolyn P

    2013-06-01

    Black/African American and Latino communities are disproportionately affected by the domestic HIV/AIDS epidemic. Blacks/African Americans and Latinos are also more likely to report a formal, religious, or faith affiliation when compared with non-Hispanic whites. As such, faith leaders and their institutions have been identified in the National HIV/AIDS Strategy as having a vital role to serve in reducing: (1) HIV-related health disparities and (2) the number of new HIV infections by promoting non-judgmental support for persons living with and at risk for HIV/AIDS and by serving as trusted information resources for their congregants and communities. We describe faith doctrines and faith-science partnerships that are increasing in support of faith-based HIV prevention and service delivery activities and discuss the vital role of these faith-based efforts in highly affected black/African American and Latino communities.

  2. Diverse HIV epidemics among people who inject drugs in Thailand: evidence from respondent-driven sampling surveys in Bangkok and Chiang Mai.

    Science.gov (United States)

    Prybylski, Dimitri; Manopaiboon, Chomnad; Visavakum, Prin; Yongvanitjit, Kovit; Aramrattana, Apinun; Manomaipiboon, Parnrudee; Tanpradech, Suvimon; Suksripanich, Orapin; Pattanasin, Sarika; Wolfe, Mitchell; Whitehead, Sara J

    2015-03-01

    Thailand's long-standing HIV sero-sentinel surveillance system for people who inject drugs (PWID) is confined to those in methadone-based drug treatment clinics and representative data are scarce, especially outside of Bangkok. We conducted probability-based respondent-driven sampling (RDS) surveys in Bangkok (n=738) and Chiang Mai (n=309) to increase understanding of local HIV epidemics and to better inform the planning of evidence-based interventions. PWID had different epidemiological profiles in these two cities. Overall HIV prevalence was higher in Bangkok (23.6% vs. 10.9%, pChiang Mai, HIV infections appear to be more recently acquired and PWID were younger and had higher levels of recent injecting and sexual risk behaviors with lower levels of intervention exposure. Methamphetamine was the predominant drug injected in both sites and polydrug use was common although levels and patterns of the specific drugs injected varied significantly between the sites. In multivariate analysis, recent midazolam injection was significantly associated with HIV infection in Chiang Mai (adjusted odds ratio=8.1; 95% confidence interval: 1.2-54.5) whereas in Bangkok HIV status was not associated with recent risk behaviors as infections had likely been acquired in the past. PWID epidemics in Thailand are heterogeneous and driven by local factors. There is a need to customize intervention strategies for PWID in different settings and to integrate population-based survey methods such as RDS into routine surveillance to monitor the national response. Published by Elsevier Ireland Ltd.

  3. Estimating the impact of state budget cuts and redirection of prevention resources on the HIV epidemic in 59 California local health departments.

    Science.gov (United States)

    Lin, Feng; Lasry, Arielle; Sansom, Stephanie L; Wolitski, Richard J

    2013-01-01

    In the wake of a national economic downturn, the state of California, in 2009-2010, implemented budget cuts that eliminated state funding of HIV prevention and testing. To mitigate the effect of these cuts remaining federal funds were redirected. This analysis estimates the impact of these budget cuts and reallocation of resources on HIV transmission and associated HIV treatment costs. We estimated the effect of the budget cuts and reallocation for California county health departments (excluding Los Angeles and San Francisco) on the number of individuals living with or at-risk for HIV who received HIV prevention services. We used a Bernoulli model to estimate the number of new infections that would occur each year as a result of the changes, and assigned lifetime treatment costs to those new infections. We explored the effect of redirecting federal funds to more cost-effective programs, as well as the potential effect of allocating funds proportionately by transmission category. We estimated that cutting HIV prevention resulted in 55 new infections that were associated with $20 million in lifetime treatment costs. The redirection of federal funds to more cost-effective programs averted 15 HIV infections. If HIV prevention funding were allocated proportionately to transmission categories, we estimated that HIV infections could be reduced below the number that occurred annually before the state budget cuts. Reducing funding for HIV prevention may result in short-term savings at the expense of additional HIV infections and increased HIV treatment costs. Existing HIV prevention funds would likely have a greater impact on the epidemic if they were allocated to the more cost-effective programs and the populations most likely to acquire and transmit the infection.

  4. Addressing the dual health epidemics of HIV and sexual abuse among children and adolescents in Kenya: uptake of HIV counseling and post-exposure prophylaxis

    Directory of Open Access Journals (Sweden)

    Ajema C

    2017-12-01

    prevention.Conclusion: Existing post-rape care services are not adequately structured to facilitate delivery of quality HIV-related services to child survivors. Health provider capacity in the management of children remains weak due to lack of skill-based training on the dynamics of responding to the needs of child survivors. There is a need for standard operating procedures and training modules on the prevention of HIV in the context of child sexual abuse. Keywords: child sexual abuse, post-rape care, sexual violence, HIV, PEP, children in Kenya

  5. Controlling the HIV/AIDS epidemic: current status and global challenges

    Directory of Open Access Journals (Sweden)

    Thorsten eDemberg

    2012-08-01

    Full Text Available This review provides an overview of the current status of the global HIV pandemic and strategies to bring it under control. It updates numerous preventive approaches including behavioral interventions, male circumcision, pre- and post-exposure prophylaxis, vaccines, and microbicides. The manuscript summarizes current anti-retroviral treatment options, their impact in the western world, and difficulties faced by emerging and resource-limited nations in providing and maintaining appropriate treatment regimens. Current clinical and pre-clinical approaches towards a cure for HIV are described, including new drug compounds that target viral reservoirs and gene therapy approaches aimed at altering susceptibility to HIV infection. Recent progress in vaccine development is summarized, including novel approaches and new discoveries.

  6. Female spouses of injection drug users in Pakistan: a bridge population of the HIV epidemic?

    Science.gov (United States)

    Ahmad, S; Mehmood, J; Awan, A B; Zafar, S T; Khoshnood, K; Khan, A A

    2011-04-01

    An estimated 21% of injection drug users (IDUs) in Pakistan are HIV-positive and data suggest that the spouses of IDUs may be a critical component of the HIV transmission chain. This study interviewed 101 spouses of male IDUs about their sexual practices and drug use. We found that 43% had been sexually active with their partners in the past month but only 4% reported selling sex. Almost a quarter (23%) used drugs and 19% injected drugs, usually a combination of diazepam and pheniramine. Although sex work was infrequent among spouses of IDUs, their risk of contracting HIV and transmitting it to others was high because they received injection drugs, sometimes along with their IDU husbands, from the same health centres that provided therapeutic injections to the rest of the community. IDU spouses may thus serve as a bridge group via therapeutic injections, rather than via sex work.

  7. Structural and Behavioral Correlates of HIV Infection among Pregnant Women in a Country with a Highly Generalized HIV Epidemic: A Cross-Sectional Study with a Probability Sample of Antenatal Care Facilities in Swaziland.

    Science.gov (United States)

    Lukhele, Bhekumusa Wellington; Techasrivichien, Teeranee; Suguimoto, S Pilar; Musumari, Patou Masika; El-Saaidi, Christina; Haumba, Samson; Tagutanazvo, Oslinah Buru; Ono-Kihara, Masako; Kihara, Masahiro

    2016-01-01

    HIV disproportionately affects women in Sub-Saharan Africa. Swaziland bears the highest HIV prevalence of 41% among pregnant women in this region. This heightened HIV-epidemic reflects the importance of context-specific interventions. Apart from routine HIV surveillance, studies that examine structural and behavioral factors associated with HIV infection among women may facilitate the revitalization of existing programs and provide insights to inform context-specific HIV prevention interventions. This cross-sectional study employed a two-stage random cluster sampling in ten antenatal health care facilities in the Hhohho region of Swaziland in August and September 2015. Participants were eligible for the study if they were 18 years or older and had tested for HIV. Self-administered tablet-based questionnaires were used to assess HIV risk factors. Of all eligible pregnant women, 827 (92.4%) participated, out of which 297 (35.9%) were self-reportedly HIV positive. Among structural factors, family function was not significantly associated with self-reported HIV positive status, while lower than high school educational attainment (AOR, 1.65; CI, 1.14-3.38; P = 0.008), and income below minimum wage (AOR, 1.81; CI, 1.09-3.01; P = 0.021) were significantly associated with self-reported HIV positive status. Behavioral factors significantly associated with reporting a positive HIV status included; ≥2 lifetime sexual partners (AOR, 3.16; CI, 2.00-5.00; PHIV/AIDS-related knowledge level was high but not associated to self-reported HIV status (P = 0.319). Structural and behavioral factors showed significant association with self-reported HIV infection among pregnant women in Swaziland while HIV/AIDS-related knowledge and family function did not. This suggests that HIV interventions should be reinforced taking into consideration these findings. The findings also suggest the importance of future research sensitive to the Swazi and African sociocultural contexts, especially

  8. Optimal control of HIV/AIDS dynamic: Education and treatment

    Science.gov (United States)

    Sule, Amiru; Abdullah, Farah Aini

    2014-07-01

    A mathematical model which describes the transmission dynamics of HIV/AIDS is developed. The optimal control representing education and treatment for this model is explored. The existence of optimal Control is established analytically by the use of optimal control theory. Numerical simulations suggest that education and treatment for the infected has a positive impact on HIV/AIDS control.

  9. THE CHURCH'S RESPONSE TO THE HIV/AIDS EPIDEMIC IN INDIA

    African Journals Online (AJOL)

    2009-12-01

    Dec 1, 2009 ... A student recounted to me what had happened in his family. ... Having approached this context through a case study which .... studies have reported that the HIV infection rates are increasing .... and medical care, and the provision of national and international .... different states or even foreign countries.

  10. Estimating the size of the HIV epidemic among injecting drug users in Amsterdam

    NARCIS (Netherlands)

    van Haastrecht, H. J.; Bindels, P. J.; van den Hoek, A. A.; Coutinho, R. A.

    1997-01-01

    Aim of this study was to assess the cumulative incidence of HIV-infection, AIDS and pre-AIDS death in the population of injecting drug users (IDU) in Amsterdam. By assuming equivalence, between a cohort of IDU and the IDU population, of the ratios of incidences of AIDS and pre-AIDS death to the

  11. THE CHURCH'S RESPONSE TO THE HIV/AIDS EPIDEMIC IN INDIA

    African Journals Online (AJOL)

    2009-12-01

    Dec 1, 2009 ... Having approached this context through a case study which enables us to delve into the ... and private hospital-based or independent clinical laboratories. Their .... run to cover 152 stations in 22 states it offered HIV testing, treatment .... produced on a large scale in India due to patent issues that control drug.

  12. Deciphering Dynamics of Recent Epidemic Spread and Outbreak in West Africa: The Case of Ebola Virus

    Science.gov (United States)

    Upadhyay, Ranjit Kumar; Roy, Parimita

    Recently, the 2014 Ebola virus (EBOV) outbreak in West Africa was the largest outbreak to date. In this paper, an attempt has been made for modeling the virus dynamics using an SEIR model to better understand and characterize the transmission trajectories of the Ebola outbreak. We compare the simulated results with the most recent reported data of Ebola infected cases in the three most affected countries Guinea, Liberia and Sierra Leone. The epidemic model exhibits two equilibria, namely, the disease-free and unique endemic equilibria. Existence and local stability of these equilibria are explored. Using central manifold theory, it is established that the transcritical bifurcation occurs when basic reproduction number passes through unity. The proposed Ebola epidemic model provides an estimate to the potential number of future cases. The model indicates that the disease will decline after peaking if multisectorial and multinational efforts to control the spread of infection are maintained. Possible implication of the results for disease eradication and its control are discussed which suggests that proper control strategies like: (i) transmission precautions, (ii) isolation and care of infectious Ebola patients, (iii) safe burial, (iv) contact tracing with follow-up and quarantine, and (v) early diagnosis are needed to stop the recurrent outbreak.

  13. Non-stationary dynamics of climate variability in synchronous influenza epidemics in Japan

    Science.gov (United States)

    Onozuka, Daisuke; Hagihara, Akihito

    2015-09-01

    Seasonal variation in the incidence of influenza is widely assumed. However, few studies have examined non-stationary relationships between global climate factors and influenza epidemics. We examined the monthly incidence of influenza in Fukuoka, Japan, from 2000 to 2012 using cross-wavelet coherency analysis to assess the patterns of associations between indices for the Indian Ocean Dipole (IOD) and El Niño Southern Oscillation (ENSO). The monthly incidence of influenza showed cycles of 1 year with the IOD and 2 years with ENSO indices (Multivariate, Niño 4, and Niño 3.4). These associations were non-stationary and appeared to have major influences on the synchrony of influenza epidemics. Our study provides quantitative evidence that non-stationary associations have major influences on synchrony between the monthly incidence of influenza and the dynamics of the IOD and ENSO. Our results call for the consideration of non-stationary patterns of association between influenza cases and climatic factors in early warning systems.

  14. Multiple Introduction and Naturally Occuring Drug Resistance of HCV among HIV-Infected Intravenous Drug Users in Yunnan: An Origin of China's HIV/HCV Epidemics.

    Directory of Open Access Journals (Sweden)

    Min Chen

    Full Text Available The human immunodeficiency virus 1 (HIV-1 epidemic in China historically stemmed from intravenous drug users (IDUs in Yunnan. Due to a shared transmission route, hepatitis C virus (HCV/HIV-1 co-infection is common. Here, we investigated HCV genetic characteristics and baseline drug resistance among HIV-infected IDUs in Yunnan.Blood samples of 432 HIV-1/HCV co-infected IDUs were collected from January to June 2014 in six prefectures of Yunnan Province. Partial E1E2 and NS5B genes were sequenced. Phylogenetic, evolutionary and genotypic drug resistance analyses were performed.Among the 293 specimens successfully genotyped, seven subtypes were identified, including subtypes 3b (37.9%, 111/293, 3a (21.8%, 64/293, 6n (14.0%, 41/293, 1b (10.6%, 31/293, 1a (8.2%, 24/293, 6a (5.1%, 15/293 and 6u (2.4%, 7/293. The distribution of HCV subtypes was mostly related to geographic location. Subtypes 3b, 3a, and 6n were detected in all six prefectures, however, the other four subtypes were detected only in parts of the six prefectures. Phylogeographic analyses indicated that 6n, 1a and 6u originated in the western prefecture (Dehong and spread eastward and showed genetic relatedness with those detected in Burmese. However, 6a originated in the southeast prefectures (Honghe and Wenshan bordering Vietnam and was transmitted westward. These subtypes exhibited different evolutionary rates (between 4.35×10-4 and 2.38×10-3 substitutions site-1 year-1 and times of most recent common ancestor (tMRCA, between 1790.3 and 1994.6, suggesting that HCV was multiply introduced into Yunnan. Naturally occurring resistance-associated mutations (C316N, A421V, C445F, I482L, V494A, and V499A to NS5B polymerase inhibitors were detected in direct-acting antivirals (DAAs-naïve IDUs.This work reveals the temporal-spatial distribution of HCV subtypes and baseline HCV drug resistance among HIV-infected IDUs in Yunnan. The findings enhance our understanding of the characteristics and

  15. Mean-field modeling approach for understanding epidemic dynamics in interconnected networks

    International Nuclear Information System (INIS)

    Zhu, Guanghu; Fu, Xinchu; Tang, Qinggan; Li, Kezan

    2015-01-01

    Modern systems (e.g., social, communicant, biological networks) are increasingly interconnected each other formed as ‘networks of networks’. Such complex systems usually possess inconsistent topologies and permit agents distributed in different subnetworks to interact directly/indirectly. Corresponding dynamics phenomena, such as the transmission of information, power, computer virus and disease, would exhibit complicated and heterogeneous tempo-spatial patterns. In this paper, we focus on the scenario of epidemic spreading in interconnected networks. We intend to provide a typical mean-field modeling framework to describe the time-evolution dynamics, and offer some mathematical skills to study the spreading threshold and the global stability of the model. Integrating the research with numerical analysis, we are able to quantify the effects of networks structure and epidemiology parameters on the transmission dynamics. Interestingly, we find that the diffusion transition in the whole network is governed by a unique threshold, which mainly depends on the most heterogenous connection patterns of network substructures. Further, the dynamics is highly sensitive to the critical values of cross infectivity with switchable phases.

  16. Dispersion of the HIV-1 Epidemic in Men Who Have Sex with Men in the Netherlands: A Combined Mathematical Model and Phylogenetic Analysis.

    Directory of Open Access Journals (Sweden)

    Daniela Bezemer

    2015-11-01

    Full Text Available The HIV-1 subtype B epidemic amongst men who have sex with men (MSM is resurgent in many countries despite the widespread use of effective combination antiretroviral therapy (cART. In this combined mathematical and phylogenetic study of observational data, we aimed to find out the extent to which the resurgent epidemic is the result of newly introduced strains or of growth of already circulating strains.As of November 2011, the ATHENA observational HIV cohort of all patients in care in the Netherlands since 1996 included HIV-1 subtype B polymerase sequences from 5,852 patients. Patients who were diagnosed between 1981 and 1995 were included in the cohort if they were still alive in 1996. The ten most similar sequences to each ATHENA sequence were selected from the Los Alamos HIV Sequence Database, and a phylogenetic tree was created of a total of 8,320 sequences. Large transmission clusters that included ≥10 ATHENA sequences were selected, with a local support value ≥ 0.9 and median pairwise patristic distance below the fifth percentile of distances in the whole tree. Time-varying reproduction numbers of the large MSM-majority clusters were estimated through mathematical modeling. We identified 106 large transmission clusters, including 3,061 (52% ATHENA and 652 Los Alamos sequences. Half of the HIV sequences from MSM registered in the cohort in the Netherlands (2,128 of 4,288 were included in 91 large MSM-majority clusters. Strikingly, at least 54 (59% of these 91 MSM-majority clusters were already circulating before 1996, when cART was introduced, and have persisted to the present. Overall, 1,226 (35% of the 3,460 diagnoses among MSM since 1996 were found in these 54 long-standing clusters. The reproduction numbers of all large MSM-majority clusters were around the epidemic threshold value of one over the whole study period. A tendency towards higher numbers was visible in recent years, especially in the more recently introduced clusters

  17. Threshold Dynamics in Stochastic SIRS Epidemic Models with Nonlinear Incidence and Vaccination

    Directory of Open Access Journals (Sweden)

    Lei Wang

    2017-01-01

    Full Text Available In this paper, the dynamical behaviors for a stochastic SIRS epidemic model with nonlinear incidence and vaccination are investigated. In the models, the disease transmission coefficient and the removal rates are all affected by noise. Some new basic properties of the models are found. Applying these properties, we establish a series of new threshold conditions on the stochastically exponential extinction, stochastic persistence, and permanence in the mean of the disease with probability one for the models. Furthermore, we obtain a sufficient condition on the existence of unique stationary distribution for the model. Finally, a series of numerical examples are introduced to illustrate our main theoretical results and some conjectures are further proposed.

  18. The global dynamics for a stochastic SIS epidemic model with isolation

    Science.gov (United States)

    Chen, Yiliang; Wen, Buyu; Teng, Zhidong

    2018-02-01

    In this paper, we investigate the dynamical behavior for a stochastic SIS epidemic model with isolation which is as an important strategy for the elimination of infectious diseases. It is assumed that the stochastic effects manifest themselves mainly as fluctuation in the transmission coefficient, the death rate and the proportional coefficient of the isolation of infective. It is shown that the extinction and persistence in the mean of the model are determined by a threshold value R0S . That is, if R0S 1, then the disease is stochastic persistent in the means with probability one. Furthermore, the existence of a unique stationary distribution is discussed, and the sufficient conditions are established by using the Lyapunov function method. Finally, some numerical examples are carried out to confirm the analytical results.

  19. Nonlinear multi-analysis of agent-based financial market dynamics by epidemic system

    Science.gov (United States)

    Lu, Yunfan; Wang, Jun; Niu, Hongli

    2015-10-01

    Based on the epidemic dynamical system, we construct a new agent-based financial time series model. In order to check and testify its rationality, we compare the statistical properties of the time series model with the real stock market indices, Shanghai Stock Exchange Composite Index and Shenzhen Stock Exchange Component Index. For analyzing the statistical properties, we combine the multi-parameter analysis with the tail distribution analysis, the modified rescaled range analysis, and the multifractal detrended fluctuation analysis. For a better perspective, the three-dimensional diagrams are used to present the analysis results. The empirical research in this paper indicates that the long-range dependence property and the multifractal phenomenon exist in the real returns and the proposed model. Therefore, the new agent-based financial model can recurrence some important features of real stock markets.

  20. The Dynamics of an HIV/AIDS Model with Screened Disease Carriers

    Directory of Open Access Journals (Sweden)

    S. D. Hove-Musekwa

    2009-01-01

    Full Text Available The presence of carriers usually complicates the dynamics and prevention of a disease. They are not recognized as disease cases themselves unless they are screened and they usually spread the infection without them being aware. We argue that this has been one of the major causes of the spread of human immunodeficiency virus (HIV. We propose, in this paper, a model for the heterogeneous transmission of HIV/acquired immunodeficiency syndrome in the presence of disease carriers. The model allows us to assess the role of screening, as an intervention program that can slow the epidemic. A threshold value ψ*, for the screening rate is obtained. It is shown numerically that if 80% or more of the carrier population is screened, the epidemic can be contained. The qualitative analysis is done in terms of the model reproduction number R. The model has two equilibria, the disease free equilibrium and a unique endemic equilibrium. The disease free equilibrium is globally stable of R  1. A detailed discussion of the model reproduction number is given and numerical simulations are done to show the role of some of the important model parameters.

  1. Status of HIV Epidemic Control Among Adolescent Girls and Young Women Aged 15-24 Years - Seven African Countries, 2015-2017.

    Science.gov (United States)

    Brown, Kristin; Williams, Daniel B; Kinchen, Steve; Saito, Suzue; Radin, Elizabeth; Patel, Hetal; Low, Andrea; Delgado, Stephen; Mugurungi, Owen; Musuka, Godfrey; Tippett Barr, Beth A; Nwankwo-Igomu, E Amaka; Ruangtragool, Leala; Hakim, Avi J; Kalua, Thokozani; Nyirenda, Rose; Chipungu, Gertrude; Auld, Andrew; Kim, Evelyn; Payne, Danielle; Wadonda-Kabondo, Nellie; West, Christine; Brennan, Elizabeth; Deutsch, Beth; Worku, Anteneh; Jonnalagadda, Sasi; Mulenga, Lloyd B; Dzekedzeke, Kumbutso; Barradas, Danielle T; Cai, Haotian; Gupta, Sundeep; Kamocha, Stanley; Riggs, Margaret A; Sachathep, Karampreet; Kirungi, Wilford; Musinguzi, Joshua; Opio, Alex; Biraro, Sam; Bancroft, Elizabeth; Galbraith, Jennifer; Kiyingi, Herbert; Farahani, Mansoor; Hladik, Wolfgang; Nyangoma, Edith; Ginindza, Choice; Masangane, Zandile; Mhlanga, Fortune; Mnisi, Zandile; Munyaradzi, Pasipamire; Zwane, Amos; Burke, Sean; Kayigamba, Felix B; Nuwagaba-Biribonwoha, Harriet; Sahabo, Ruben; Ao, Trong T; Draghi, Chiara; Ryan, Caroline; Philip, Neena M; Mosha, Fausta; Mulokozi, Aroldia; Ntigiti, Phausta; Ramadhani, Angela A; Somi, Geoffrey R; Makafu, Cecilia; Mugisha, Veronicah; Zelothe, Julius; Lavilla, Kayla; Lowrance, David W; Mdodo, Rennatus; Gummerson, Elizabeth; Stupp, Paul; Thin, Kyaw; Frederix, Koen; Davia, Stefania; Schwitters, Amee M; McCracken, Stephen D; Duong, Yen T; Hoos, David; Parekh, Bharat; Justman, Jessica E; Voetsch, Andrew C

    2018-01-12

    In 2016, an estimated 1.5 million females aged 15-24 years were living with human immunodeficiency virus (HIV) infection in Eastern and Southern Africa, where the prevalence of HIV infection among adolescent girls and young women (3.4%) is more than double that for males in the same age range (1.6%) (1). Progress was assessed toward the Joint United Nations Programme on HIV/AIDS (UNAIDS) 2020 targets for adolescent girls and young women in sub-Saharan Africa (90% of those with HIV infection aware of their status, 90% of HIV-infected persons aware of their status on antiretroviral treatment [ART], and 90% of those on treatment virally suppressed [HIV viral load girls and young women aged 15-24 years, the percentage who were aware of their status, and among those persons who were aware, the percentage who had achieved viral suppression were calculated. The target for viral suppression among all persons with HIV infection is 73% (the product of 90% x 90% x 90%). Among all seven countries, the prevalence of HIV infection among adolescent girls and young women was 3.6%; among those in this group, 46.3% reported being aware of their HIV-positive status, and 45.0% were virally suppressed. Sustained efforts by national HIV and public health programs to diagnose HIV infection in adolescent girls and young women as early as possible to ensure rapid initiation of ART should help achieve epidemic control among adolescent girls and young women.

  2. Are HIV epidemics among men who have sex with men emerging in the Middle East and North Africa?: a systematic review and data synthesis.

    Directory of Open Access Journals (Sweden)

    Ghina Mumtaz

    2010-08-01

    Full Text Available BACKGROUND: Men who have sex with men (MSM bear a disproportionately higher burden of HIV infection than the general population. MSM in the Middle East and North Africa (MENA are a largely hidden population because of a prevailing stigma towards this type of sexual behavior, thereby limiting the ability to assess infection transmission patterns among them. It is widely perceived that data are virtually nonexistent on MSM and HIV in this region. The objective of this review was to delineate, for the first time, the evidence on the epidemiology of HIV among MSM in MENA. METHODS AND FINDINGS: This was a systematic review of all biological, behavioral, and other related data on HIV and MSM in MENA. Sources of data included PubMed (Medline, international organizations' reports and databases, country-level reports and databases including governmental and nongovernmental organization publications, and various other institutional documents. This review showed that onsiderable data are available on MSM and HIV in MENA. While HIV prevalence continues at low levels among different MSM groups, HIV epidemics appear to be emerging in at least few countries, with a prevalence reaching up to 28% among certain MSM groups. By 2008, the contribution of MSM transmission to the total HIV notified cases increased and exceeded 25% in several countries. The high levels of risk behavior (4-14 partners on average in the last six months among different MSM populations and of biomarkers of risks (such as herpes simplex virus type 2 at 3%-54%, the overall low rate of consistent condom use (generally below 25%, the relative frequency of male sex work (20%-76%, and the substantial overlap with heterosexual risk behavior and injecting drug use suggest potential for further spread. CONCLUSIONS: This systematic review and data synthesis indicate that HIV epidemics appear to be emerging among MSM in at least a few MENA countries and could already be in a concentrated state among

  3. The Artificial Hamiltonian, First Integrals, and Closed-Form Solutions of Dynamical Systems for Epidemics

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    Naz, Rehana; Naeem, Imran

    2018-03-01

    The non-standard Hamiltonian system, also referred to as a partial Hamiltonian system in the literature, of the form {\\dot q^i} = {partial H}/{partial {p_i}},\\dot p^i = - {partial H}/{partial {q_i}} + {Γ ^i}(t,{q^i},{p_i}) appears widely in economics, physics, mechanics, and other fields. The non-standard (partial) Hamiltonian systems arise from physical Hamiltonian structures as well as from artificial Hamiltonian structures. We introduce the term `artificial Hamiltonian' for the Hamiltonian of a model having no physical structure. We provide here explicitly the notion of an artificial Hamiltonian for dynamical systems of ordinary differential equations (ODEs). Also, we show that every system of second-order ODEs can be expressed as a non-standard (partial) Hamiltonian system of first-order ODEs by introducing an artificial Hamiltonian. This notion of an artificial Hamiltonian gives a new way to solve dynamical systems of first-order ODEs and systems of second-order ODEs that can be expressed as a non-standard (partial) Hamiltonian system by using the known techniques applicable to the non-standard Hamiltonian systems. We employ the proposed notion to solve dynamical systems of first-order ODEs arising in epidemics.

  4. Simulation modelling of population dynamics of mosquito vectors for rift valley Fever virus in a disease epidemic setting.

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    Clement N Mweya

    Full Text Available Rift Valley Fever (RVF is weather dependent arboviral infection of livestock and humans. Population dynamics of mosquito vectors is associated with disease epidemics. In our study, we use daily temperature and rainfall as model inputs to simulate dynamics of mosquito vectors population in relation to disease epidemics.Time-varying distributed delays (TVDD and multi-way functional response equations were implemented to simulate mosquito vectors and hosts developmental stages and to establish interactions between stages and phases of mosquito vectors in relation to vertebrate hosts for infection introduction in compartmental phases. An open-source modelling platforms, Universal Simulator and Qt integrated development environment were used to develop models in C++ programming language. Developed models include source codes for mosquito fecundity, host fecundity, water level, mosquito infection, host infection, interactions, and egg time. Extensible Markup Language (XML files were used as recipes to integrate source codes in Qt creator with Universal Simulator plug-in. We observed that Floodwater Aedines and Culicine population continued to fluctuate with temperature and water level over simulation period while controlled by availability of host for blood feeding. Infection in the system was introduced by floodwater Aedines. Culicines pick infection from infected host once to amplify disease epidemic. Simulated mosquito population show sudden unusual increase between December 1997 and January 1998 a similar period when RVF outbreak occurred in Ngorongoro district.Findings presented here provide new opportunities for weather-driven RVF epidemic simulation modelling. This is an ideal approach for understanding disease transmission dynamics towards epidemics prediction, prevention and control. This approach can be used as an alternative source for generation of calibrated RVF epidemics data in different settings.

  5. Simulation modelling of population dynamics of mosquito vectors for rift valley Fever virus in a disease epidemic setting.

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    Mweya, Clement N; Holst, Niels; Mboera, Leonard E G; Kimera, Sharadhuli I

    2014-01-01

    Rift Valley Fever (RVF) is weather dependent arboviral infection of livestock and humans. Population dynamics of mosquito vectors is associated with disease epidemics. In our study, we use daily temperature and rainfall as model inputs to simulate dynamics of mosquito vectors population in relation to disease epidemics. Time-varying distributed delays (TVDD) and multi-way functional response equations were implemented to simulate mosquito vectors and hosts developmental stages and to establish interactions between stages and phases of mosquito vectors in relation to vertebrate hosts for infection introduction in compartmental phases. An open-source modelling platforms, Universal Simulator and Qt integrated development environment were used to develop models in C++ programming language. Developed models include source codes for mosquito fecundity, host fecundity, water level, mosquito infection, host infection, interactions, and egg time. Extensible Markup Language (XML) files were used as recipes to integrate source codes in Qt creator with Universal Simulator plug-in. We observed that Floodwater Aedines and Culicine population continued to fluctuate with temperature and water level over simulation period while controlled by availability of host for blood feeding. Infection in the system was introduced by floodwater Aedines. Culicines pick infection from infected host once to amplify disease epidemic. Simulated mosquito population show sudden unusual increase between December 1997 and January 1998 a similar period when RVF outbreak occurred in Ngorongoro district. Findings presented here provide new opportunities for weather-driven RVF epidemic simulation modelling. This is an ideal approach for understanding disease transmission dynamics towards epidemics prediction, prevention and control. This approach can be used as an alternative source for generation of calibrated RVF epidemics data in different settings.

  6. Enhancement of epidemic spread by noise and stochastic resonance in spatial network models with viral dynamics.

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    Tuckwell, H C; Toubiana, L; Vibert, J F

    2000-05-01

    We extend a previous dynamical viral network model to include stochastic effects. The dynamical equations for the viral and immune effector densities within a host population of size n are bilinear, and the noise is white, additive, and Gaussian. The individuals are connected with an n x n transmission matrix, with terms which decay exponentially with distance. In a single individual, for the range of noise parameters considered, it is found that increasing the amplitude of the noise tends to decrease the maximum mean virion level, and slightly accelerate its attainment. Two different spatial dynamical models are employed to ascertain the effects of environmental stochasticity on viral spread. In the first model transmission is unrestricted and there is no threshold within individuals. This model has the advantage that it can be analyzed using a Fokker-Planck approach. The noise is found both to synchronize and uniformize the trajectories of the viral levels across the population of infected individuals, and thus to promote the epidemic spread of the virus. Quantitative measures of the speed of spread and overall amplitude of the epidemic are obtained as functions of the noise and virulence parameters. The mean amplitude increases steadily without threshold effects for a fixed value of the virulence as the noise amplitude sigma is increased, and there is no evidence of a stochastic resonance. However, the speed of transmission, both with respect to its mean and variance, undergoes rapid increases as sigma changes by relatively small amounts. In the second, more realistic, model, there is a threshold for infection and an upper limit to the transmission rate. There may be no spread of infection at all in the absence of noise. With increasing noise level and a low threshold, the mean maximum virion level grows quickly and shows a broad-based stochastic resonance effect. When the threshold within individuals is increased, the mean population virion level increases only

  7. Multi-Sector Participation In The National Response To Prevent And Address The Hiv/Aids Epidemic In The Republic Of Cuba, 2007-2008

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    Isora Ramos Valle

    2010-12-01

    Full Text Available The development of a strong national response involving multiple sectors—including civil society—is an essential aspect of the social management of the HIV/AIDS epidemic. The goals of this response are to control the epidemic and improve the quality of life for people living with HIV/AIDS; this includes combating stigma and discrimination, as well as ensuring due compliance with the law. Cuba has a national program to prevent and control HIV/AIDS. Since 2003 Cuba’s national program has received material and financial support from the Global Fund to Fight AIDS, Tuberculosis and Malaria. Program evaluation is carried out by an independent team at ENSAP (National School of Public Health. This paper reports on results of one part of that evaluation: an assessment of the agencies and sectors who made up the organized social and national response to the HIV/AIDS epidemic. The evaluation primarily used qualitative analyses of the activities and tasks proposed by sectors in their 2006-2008 work plans. Visits were made to the provinces of Ciudad de la Habana, Matanzas, and Holguín. Qualitative techniques included in-depth interviews, semi-structured interviews, observation, and review of documentary evidence of all kinds (videos, reports, minutes, protocols, results of social research, and radio broadcast messages and varied depending on the particular features of each sector. We noted improvements in multi-sector participation in the prevention and response to the national HIV/AIDS epidemic. Conscious of their role, sectors generally carried out their programmed activities and had improved their organization, planning, and systematization; integration among the sectors was also better. These local initiatives provided evidence of a multi-sector response characterized by autonomy, emotional involvement, and an identification with the goals of the project; this went beyond simply meeting targets. Cross-sector work showed a marked increase and a

  8. Diverse HIV epidemics among people who inject drugs in Thailand: Evidence from respondent-driven sampling surveys in Bangkok and Chiang Mai☆

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    Prybylski, Dimitri; Manopaiboon, Chomnad; Visavakum, Prin; Yongvanitjit, Kovit; Aramrattana, Apinun; Manomaipiboon, Parnrudee; Tanpradech, Suvimon; Suksripanich, Orapin; Pattanasin, Sarika; Wolfe, Mitchell; Whitehead, Sara J.

    2016-01-01

    Background Thailand’s long-standing HIV sero-sentinel surveillance system for people who inject drugs (PWID) is confined to those in methadone-based drug treatment clinics and representative data are scarce, especially outside of Bangkok. Methods We conducted probability-based respondent-driven sampling (RDS) surveys in Bangkok (n = 738) and Chiang Mai (n = 309) to increase understanding of local HIV epidemics and to better inform the planning of evidence-based interventions. Results PWID had different epidemiological profiles in these two cities. Overall HIV prevalence was higher in Bangkok (23.6% vs. 10.9%, p Chiang Mai, HIV infections appear to be more recently acquired and PWID were younger and had higher levels of recent injecting and sexual risk behaviors with lower levels of intervention exposure. Methamphetamine was the predominant drug injected in both sites and polydrug use was common although levels and patterns of the specific drugs injected varied significantly between the sites. In multivariate analysis, recent midazolam injection was significantly associated with HIV infection in Chiang Mai (adjusted odds ratio = 8.1; 95% confidence interval: 1.2–54.5) whereas in Bangkok HIV status was not associated with recent risk behaviors as infections had likely been acquired in the past. Conclusion PWID epidemics in Thailand are heterogeneous and driven by local factors. There is a need to customize intervention strategies for PWID in different settings and to integrate population-based survey methods such as RDS into routine surveillance to monitor the national response. PMID:25640153

  9. Corporate social responsibility in public health: A case-study on HIV/AIDS epidemic by Johnson & Johnson company in Africa.

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    Chattu, Vijay Kumar

    2015-01-01

    HIV/AIDS has claimed millions of lives in the global workforce and continues to remain a threat to many businesses. An estimated 36.5 million of working people are living with HIV; the global workforce has lost 28 million people from AIDS since the beginning of the epidemic. In the absence of access to treatment, this number could grow to 74 million by 2015. The epidemic continues to affect the working population through absenteeism, sickness and death. Corporate Social Responsibility (CSR) is an obligation that corporates have toward their employees, community and society. A review and documentation of one such CSR by Johnson & Johnson (a multinational company) for HIV/AIDS in Africa is presented here. Johnson & Johnson Company is involved in numerous projects around the world to combat the HIV/AIDS epidemic. The company is working to fight the spread of the disease and improve the quality of life for those living with the illness through various donations of its products and sponsorship of local programs. This case study also highlights different categories of CSR activities such as Cause Promotion, Cause related Marketing, Corporate Philanthropy, Corporate Social Marketing, Corporate Volunteering and Socially responsible business practices, which are discussed with specific examples from different countries in Africa. CSR of any business encompasses the economic, legal, ethical & discretionary expectation placed on the organization by society at a given point of time. CSR is therefore the obligation that corporations have toward their stakeholders and society in general which horizons beyond what is prescribed by law or union contracts. Johnson & Johnson has a proved history of being committed to caring for people and a good example of a company with a long history of citizenship and sustainability.

  10. Corporate social responsibility in public health: A case-study on HIV/AIDS epidemic by Johnson & Johnson company in Africa

    Science.gov (United States)

    Chattu, Vijay Kumar

    2015-01-01

    HIV/AIDS has claimed millions of lives in the global workforce and continues to remain a threat to many businesses. An estimated 36.5 million of working people are living with HIV; the global workforce has lost 28 million people from AIDS since the beginning of the epidemic. In the absence of access to treatment, this number could grow to 74 million by 2015. The epidemic continues to affect the working population through absenteeism, sickness and death. Corporate Social Responsibility (CSR) is an obligation that corporates have toward their employees, community and society. A review and documentation of one such CSR by Johnson & Johnson (a multinational company) for HIV/AIDS in Africa is presented here. Johnson & Johnson Company is involved in numerous projects around the world to combat the HIV/AIDS epidemic. The company is working to fight the spread of the disease and improve the quality of life for those living with the illness through various donations of its products and sponsorship of local programs. This case study also highlights different categories of CSR activities such as Cause Promotion, Cause related Marketing, Corporate Philanthropy, Corporate Social Marketing, Corporate Volunteering and Socially responsible business practices, which are discussed with specific examples from different countries in Africa. Conclusions: CSR of any business encompasses the economic, legal, ethical & discretionary expectation placed on the organization by society at a given point of time. CSR is therefore the obligation that corporations have toward their stakeholders and society in general which horizons beyond what is prescribed by law or union contracts. Johnson & Johnson has a proved history of being committed to caring for people and a good example of a company with a long history of citizenship and sustainability. PMID:25810667

  11. Temporo-spatial dynamics and behavioural patterns of 2012 cholera epidemic in the African mega-city of Conakry, Guinea.

    Science.gov (United States)

    Blake, Alexandre; Keita, Veronique Sarr; Sauvageot, Delphine; Saliou, Mamadou; Njanpop, Berthe Marie; Sory, Fode; Sudre, Bertrand; Lamine, Koivogui; Mengel, Martin; Gessner, Bradford D; Sakoba, Keita

    2018-02-15

    Cholera is endemic in Guinea, having suffered consecutive outbreaks from 2004 to 2008 followed by a lull until the 2012 epidemic. Here we describe the temporal-spatial and behavioural characteristics of cholera cases in Conakry during a three-year period, including the large-scale 2012 epidemic. We used the national and African Cholera Surveillance Network (Africhol) surveillance data collected from every cholera treatment centre in Conakry city from August 2011 to December 2013. The prevalence of suspect and confirmed cholera cases, the case fatality ratio (CFR), and the factors associated with suspected cholera were described according to three periods: pre-epidemic (A), epidemic 2012 (B) and post epidemic (C). Weekly attack rates and temporal-spatial clustering were calculated at municipality level for period B. Cholera was confirmed by culture at the cholera national reference laboratory. A total of 4559 suspect cases were reported: 66, 4437, and 66 suspect cases in periods A, B and C, respectively. Among the 204 suspect cases with culture results available, 6%, 60%, and 70% were confirmed in periods A, B, and C, respectively. With 0.3%, the CFR was significantly lower in period B than in periods A (7.6%) and C (7.1%). The overall attack rate was 0.28% in period B, ranging from 0.17% to 0.31% across municipalities. Concomitantly, a cluster of cases was identified in two districts in the northern part of Conakry. At 14%, rice water stools were less frequent in period A than in period B and C (78% and 84%). Dehydration (31% vs 94% and 89%) and coma (0.4% vs 3.1% and 2.9%) were lower during period B than in periods A and C. The treatment of drinking water was less frequent in period A, while there were more reports of recent travel in period C. The epidemic dynamic and the sociological description of suspect cases before, during, and after the large-scale epidemic revealed that the Vibrio cholerae was already present before the epidemic. However, it appeared that

  12. Direct and dynamic detection of HIV-1 in living cells.

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    Jonas Helma

    Full Text Available In basic and applied HIV research, reliable detection of viral components is crucial to monitor progression of infection. While it is routine to detect structural viral proteins in vitro for diagnostic purposes, it previously remained impossible to directly and dynamically visualize HIV in living cells without genetic modification of the virus. Here, we describe a novel fluorescent biosensor to dynamically trace HIV-1 morphogenesis in living cells. We generated a camelid single domain antibody that specifically binds the HIV-1 capsid protein (CA at subnanomolar affinity and fused it to fluorescent proteins. The resulting fluorescent chromobody specifically recognizes the CA-harbouring HIV-1 Gag precursor protein in living cells and is applicable in various advanced light microscopy systems. Confocal live cell microscopy and super-resolution microscopy allowed detection and dynamic tracing of individual virion assemblies at the plasma membrane. The analysis of subcellular binding kinetics showed cytoplasmic antigen recognition and incorporation into virion assembly sites. Finally, we demonstrate the use of this new reporter in automated image analysis, providing a robust tool for cell-based HIV research.

  13. Effects of behavioral response and vaccination policy on epidemic spreading--an approach based on evolutionary-game dynamics.

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    Zhang, Hai-Feng; Wu, Zhi-Xi; Tang, Ming; Lai, Ying-Cheng

    2014-07-11

    How effective are governmental incentives to achieve widespread vaccination coverage so as to prevent epidemic outbreak? The answer largely depends on the complex interplay among the type of incentive, individual behavioral responses, and the intrinsic epidemic dynamics. By incorporating evolutionary games into epidemic dynamics, we investigate the effects of two types of incentives strategies: partial-subsidy policy in which certain fraction of the cost of vaccination is offset, and free-subsidy policy in which donees are randomly selected and vaccinated at no cost. Through mean-field analysis and computations, we find that, under the partial-subsidy policy, the vaccination coverage depends monotonically on the sensitivity of individuals to payoff difference, but the dependence is non-monotonous for the free-subsidy policy. Due to the role models of the donees for relatively irrational individuals and the unchanged strategies of the donees for rational individuals, the free-subsidy policy can in general lead to higher vaccination coverage. Our findings indicate that any disease-control policy should be exercised with extreme care: its success depends on the complex interplay among the intrinsic mathematical rules of epidemic spreading, governmental policies, and behavioral responses of individuals.

  14. Word-of-mouth dynamics with information seeking: Information is not (only) epidemics

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    Thiriot, Samuel

    2018-02-01

    Word-of-mouth is known to determine the success or failure of innovations (Rogers, 2003) and facilitate the diffusion of products (Katz and Lazarsfeld, 1955). Word-of-mouth is made of both individuals seeking out information and/or pro-actively spreading information (Gilly et al., 1998; Rogers, 2003). Information seeking is considered as a step mandatory for individuals to retrieve the expert knowledge necessary for them to understand the benefits of an innovation or decide to buy a product (Arndt, 1967; Rogers, 2003). Yet the role of information seeking in the word-of-mouth dynamics was not investigated in computational models. Here we study in which conditions word-of-mouth enables the population to retrieve the initial expertise scattered in the population. We design a computational model in which awareness and expert knowledge are both represented, and study the joint dynamics of information seeking and proactive transmission of information. Simulation experiments highlight the apparition of cascades of awareness, cascades of expertise and chains of information retrieval. We find that different strategies should be used depending on the initial proportion of expertise (disruptive innovations, incremental innovations or products belonging to well-known categories). Surprisingly, when there is too much expertise in the population prior the advertisement campaign, word-of-mouth is less efficient in the retrieval of this expertise than when less expertise is initially present. Our results suggest that information seeking plays a key role in the dynamics of word-of-mouth, which can therefore not be reduced solely to the epidemic aspect.

  15. Psychological well-being of people living with HIV/AIDS under the new epidemic characteristics in China and the risk factors: a population-based study.

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    Sun, Wei; Wu, Ming; Qu, Peng; Lu, Chunming; Wang, Lie

    2014-11-01

    The HIV/AIDS epidemic in China is growing and the main transmission mode has changed from contaminated blood products to sexual contact. The aim of this study was to evaluate the levels of anxiety (SAS; Zung Self-Rating Anxiety Scale) and depression (CES-D; Center for Epidemiologic Studies Depression Scale) among people living with HIV/AIDS (PLWHA) under the new epidemic characteristics and to examine associated factors. The sample size (N=800) was calculated on the basis of the lowest prevalence of psychological disorders among PLWHA and was enlarged taking into consideration a loss of response. Participants were sampled randomly among all PLWHA registered in Liaoning Province. Questionnaires pertaining to the SAS, CES-D, and related factors were distributed between December 2010 and April 2011; 772 effective responses were received. The prevalence of anxiety (SAS ≥40) and depression (CES-D ≥16) were 49.0% and 73.1%, respectively. Multivariate logistic regression analysis revealed that SAS was associated with self-rated health, condom use at the last sexual contact, perceived social support, alcohol consumption, and transmission; CES-D was associated with self-rated health, perceived social support, job, and sex. PLWHA under the new epidemic characteristics in China suffer from serious psychological problems. To improve their psychological well-being, efforts should be focused on improving perceptions of their health condition and increasing perceived social support.

  16. Structural and Behavioral Correlates of HIV Infection among Pregnant Women in a Country with a Highly Generalized HIV Epidemic: A Cross-Sectional Study with a Probability Sample of Antenatal Care Facilities in Swaziland.

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    Bhekumusa Wellington Lukhele

    Full Text Available HIV disproportionately affects women in Sub-Saharan Africa. Swaziland bears the highest HIV prevalence of 41% among pregnant women in this region. This heightened HIV-epidemic reflects the importance of context-specific interventions. Apart from routine HIV surveillance, studies that examine structural and behavioral factors associated with HIV infection among women may facilitate the revitalization of existing programs and provide insights to inform context-specific HIV prevention interventions.This cross-sectional study employed a two-stage random cluster sampling in ten antenatal health care facilities in the Hhohho region of Swaziland in August and September 2015. Participants were eligible for the study if they were 18 years or older and had tested for HIV. Self-administered tablet-based questionnaires were used to assess HIV risk factors. Of all eligible pregnant women, 827 (92.4% participated, out of which 297 (35.9% were self-reportedly HIV positive. Among structural factors, family function was not significantly associated with self-reported HIV positive status, while lower than high school educational attainment (AOR, 1.65; CI, 1.14-3.38; P = 0.008, and income below minimum wage (AOR, 1.81; CI, 1.09-3.01; P = 0.021 were significantly associated with self-reported HIV positive status. Behavioral factors significantly associated with reporting a positive HIV status included; ≥2 lifetime sexual partners (AOR, 3.16; CI, 2.00-5.00; P<0.001, and ever cohabited (AOR, 2.39; CI, 1.66-3.43; P = 0.00. The most cited reason for having multiple sexual partners was financial gain. HIV/AIDS-related knowledge level was high but not associated to self-reported HIV status (P = 0.319.Structural and behavioral factors showed significant association with self-reported HIV infection among pregnant women in Swaziland while HIV/AIDS-related knowledge and family function did not. This suggests that HIV interventions should be reinforced taking into

  17. Poisonous milk and sinful mothers: the changing meaning of breastfeeding in the wake of the HIV epidemic in Addis Ababa, Ethiopia

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    Blystad Astrid

    2010-10-01

    Full Text Available Abstract Background Breastfeeding remains normative and vital for child survival in the developing world. However, knowledge of the risk of Human Immunodeficiency Virus (HIV transmission through breastfeeding has brought to attention the controversy of whether breastfeeding can be safely practiced by HIV positive mothers. Prevention of mother to child transmission (PMTCT programs provide prevention services to HIV positive mothers including infant feeding counseling based on international guidelines. This study aimed at exploring infant feeding choices and how breastfeeding and the risk of HIV transmission through breastfeeding was interpreted among HIV positive mothers and their counselors in PMTCT programs in Addis Ababa, Ethiopia. Methods The study was conducted in the PMTCT clinics in two governmental hospitals in Addis Ababa, Ethiopia, using qualitative interviews and participant observation. Twenty two HIV positive mothers and ten health professionals working in PMTCT clinics were interviewed. Results The study revealed that HIV positive mothers have developed an immense fear of breast milk which is out of proportion compared to the evidence of risk of transmission documented. The fear is expressed through avoidance of breastfeeding or, if no other choice is available, through an intense unease with the breastfeeding situation, and through expressions of sin, guilt, blame and regret. Health professionals working in the PMTCT programs seemed to largely share the fear of HIV positive mother's breast milk, and their anxiety was reflected in the counseling services they provided. Formula feeding was the preferred infant feeding method, and was chosen also by HIV positive women who had to beg in the streets for survival. Conclusions The fear of breast milk that seems to have developed among counselors and HIV positive mothers in the wake of the HIV epidemic may challenge a well established breastfeeding culture and calls for public health

  18. Empirical evidence of the effect of school gathering on the dynamics of dengue epidemics

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    Carlos M. Hernández-Suárez

    2016-01-01

    Full Text Available Introduction: Dengue fever is an important vector-transmitted disease that affects more than 100 countries worldwide. Locations where individuals tend to gather may play an important role in disease transmission in the presence of the vector. By controlling mosquitoes’ breeding places, this study aims to analyze the effect of reducing transmission in elementary schools (grades 1–9 on the dynamics of the epidemic at a regional level. Materials and methods: In 2007, we implemented a massive campaign in a region of México (Colima state, 5,191 km2, population 568,000 focused on training janitors to locate and avoid mosquitoes’ breeding places, the objective being to maintain elementary schools free of mosquitoes. Results: We observed 45% reduction in dengue incidence compared to the previous year. In contrast, the rest of Mexico observed an 81% increase in incidence on average. Discussion: Costs associated with campaigns focusing on cleaning schools are very low and results seem to be promising. Nevertheless, more controlled studies are needed.

  19. 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.

  20. Demographic buffering: titrating the effects of birth rate and imperfect immunity on epidemic dynamics.

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    Morris, Sinead E; Pitzer, Virginia E; Viboud, Cécile; Metcalf, C Jessica E; Bjørnstad, Ottar N; Grenfell, Bryan T

    2015-03-06

    Host demography can alter the dynamics of infectious disease. In the case of perfectly immunizing infections, observations of strong sensitivity to demographic variation have been mechanistically explained through analysis of the susceptible-infected-recovered (SIR) model that assumes lifelong immunity following recovery from infection. When imperfect immunity is incorporated into this framework via the susceptible-infected-recovered-susceptible (SIRS) model, with individuals regaining full susceptibility following recovery, we show that rapid loss of immunity is predicted to buffer populations against the effects of demographic change. However, this buffering is contrary to the dependence on demography recently observed for partially immunizing infections such as rotavirus and respiratory syncytial virus. We show that this discrepancy arises from a key simplification embedded in the SIR(S) framework, namely that the potential for differential immune responses to repeat exposures is ignored. We explore the minimum additional immunological information that must be included to reflect the range of observed dependencies on demography. We show that including partial protection and lower transmission following primary infection is sufficient to capture more realistic reduced levels of buffering, in addition to changes in epidemic timing, across a range of partially and fully immunizing infections. Furthermore, our results identify key variables in this relationship, including R0.

  1. Dominance of HIV-1 subtype CRF01_AE in sexually acquired cases leads to a new epidemic in Yunnan province of China.

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    Yong Zhang

    2006-11-01

    Full Text Available Dating back to the first epidemic among injection drug users in 1989, the Yunnan province has had the highest number of human immunodeficiency virus type 1 (HIV-1 infections in China. However, the molecular epidemiology of HIV-1 in Yunnan has not been fully characterized.Using immunoassays, we identified 103,015 accumulated cases of HIV-1 infections in Yunnan between 1989 and 2004. We studied 321 patients representing Yunnan's 16 prefectures from four risk groups, 11 ethnic populations, and ten occupations. We identified three major circulating subtypes: C/CRF07_BC/CRF08_BC (53%, CRF01_AE (40.5%, and B (6.5% by analyzing the sequence of p17, which is part of the gag gene. For patients with known risk factors, 90.9% of injection drug users had C/CRF07_BC/CRF08_BC viruses, whereas 85.4% of CRF01_AE infections were acquired through sexual transmission. No distinct segregation of CRF01_AE viruses was found among the Dai ethnic group. Geographically, C/CRF07_BC/CRF08_BC was found throughout the province, while CRF01_AE was largely confined to the prefectures bordering Myanmar. Furthermore, C/CRF07_BC/CRF08_BC viruses were found to consist of a group of viruses, including C, CRF08_BC, CRF07_BC, and new BC recombinants, based on the characterization of their reverse transcriptase genes.This is the first report of a province-wide HIV-1 molecular epidemiological study in Yunnan. While C/CRF07_BC/CRF08_BC and CRF01_AE are codominant, the discovery of many sexually transmitted CRF01_AE cases is new and suggests that this subtype may lead to a new epidemic in the general Chinese population. We discuss implications of our results for understanding the evolution of the HIV-1 pandemic and for vaccine development.

  2. No More Broken Promises: Challenges and Opportunities for Key Populations in Demanding More Transparency, Accountability, and Participation in the Global Response Against the HIV and AIDS Epidemic.

    Science.gov (United States)

    Chang Pico, Tomás A; Kohler, Jillian Clare; Hoffmann, Julia; Mungala, Lucy

    2017-12-01

    The global fight against HIV/AIDS continues to pose challenges: infection rates are on the rise in many settings, stigma and discrimination remain rampant, and the global response is under increasing financial pressure. There is a high risk of losing what has been achieved so far in the fight against HIV and AIDS, but also the momentum to meet the so-called Fast Track targets for 2030. In light of these trends, it is fundamental to focus on the human rights of key populations (KPs)-especially to health, non-discrimination, access to information, and to equal and meaningful participation in political and public affairs-by placing them at the center of the global HIV response. Such rights, and the demand for more transparency, accountability, and participation (TAP), have been recognized as both a necessary social justice imperative, and as a way to build more responsive, inclusive, and sustainable health systems. This article will argue that embracing TAP as key guiding principles of the global HIV response (especially in low- and middle-income countries) could have the potential to create the conditions for KPs to have their human rights fulfilled, and to expand their participation in the decision-making processes that guide the efforts against the epidemic. It will then propose a number of avenues for further engagement between different communities of practice in terms of research, agendas, and policy and practices that could be beneficial in maximizing the impact of the global efforts to end HIV/AIDS.

  3. The epidemiology of HIV infection in Morocco: systematic review and data synthesis

    Science.gov (United States)

    Kouyoumjian, S P; Mumtaz, G R; Hilmi, N; Zidouh, A; El Rhilani, H; Alami, K; Bennani, A; Gouws, E; Ghys, P D; Abu-Raddad, L J

    2013-01-01

    Summary Morocco has made significant strides in building its HIV research capacity. Based on a wealth of empirical data, the objective of this study was to conduct a comprehensive and systematic literature review and analytical synthesis of HIV epidemiological evidence in this country. Data were retrieved using three major sources of literature and data. HIV transmission dynamics were found to be focused in high-risk populations, with female sex workers (FSWs) and clients contributing the largest share of new HIV infections. There is a pattern of emerging epidemics among some high-risk populations, and some epidemics, particularly among FSWs, appear to be established and stable. The scale of the local HIV epidemics and populations affected show highly heterogeneous geographical distribution. To optimize the national HIV response, surveillance and prevention efforts need to be expanded among high-risk populations and in geographic settings where low intensity and possibly concentrated HIV epidemics are emerging or are already endemic. PMID:23970764

  4. Delbruck Prize Award: Insights into HIV Dynamics and Cure

    Science.gov (United States)

    Perelson, Alan S.

    A large effort is being made to find a means to cure HIV infection. I will present a dynamical model of a phenomenon called post-treatment control (PTC) or functional cure of HIV-infection in which some patients treated with suppressive antiviral therapy have been taken off of therapy and then spontaneously control HIV infection. The model relies on an immune response and bistability to explain PTC. I will then generalize the model to explicitly include immunotherapy with monoclonal antibodies approved for use in cancer to show that one can induce PTC with a limited number of antibody infusions and compare model predictions with experiments in SIV infected macaques given immunotherapy. Lastly, I will argue that quantitative insights derived from models of HIV infection have and will continue to play an important role in medicine.

  5. Proportion of long-term injection drug users as an indicator to characterize the state and prognosis of HIV-epidemic within a certain territory

    Directory of Open Access Journals (Sweden)

    Andreeva, Tatiana

    2012-07-01

    Full Text Available BACKGROUND: Epidemics of drug use and thus the spread of HIV have different duration in different regions, and, therefore, the prognosis of these epidemics may differ. We aimed to assess indicators measuring the peculiarities of injection drug use epidemics by region, informative for prevention activities among vulnerable to HIV groups. METHODS: Data from cross-sectional survey of 4026 injection drug users (IDUs conducted in 2007 in Ukraine were analyzed. The outcome measure was a binary variable depicting whether a respondent injects drugs for 20 years and over. Binary Logistic Regression in SPSS software was used to test associations with socio-demographic characteristics. RESULTS: More respondents from Odessa, Mykolayiv, Dnipropetrovsk, Cherkassy, Poltava, and Crimea regions inject over 20 years. Older respondents were more likely to belong to the group of long-term users. Men were more likely to inject over 20 years than women. Those respondents who were married, but did not live with their spouse or other sexual partner were more likely to inject longer than 20 years compared to those single or in a stable marriage. Those respondents who use opiates or combine them with stimulants were more likely to inject over 20 years and those who use only stimulants were more likely to inject less than 20 years. CONCLUSION: Injection drug use in Ukraine started earlier among men, on certain territories and was associated with opiate use. Percentage of IDUs who inject for more than 20 years was found to be a good indicator to distinguish territories with long-lasting epidemics.

  6. Stability analysis of host dynamics for hiv

    Science.gov (United States)

    Geetha, V.; Balamuralitharan, S.

    2018-04-01

    The phenomenon of disease modeling can be easily accomplished through mathematical framework. In this paper the transmission of disease in human is represented mathematically as a nonlinear system. We think about the components of the Human Immunodeficiency Virus (HIV) among the beginning periods of illness. Throughout this paper we have determined those logical representation of a three-compartmental HIV demonstrate for their stability evaluation. We tend to likewise explore the stimulating behavior of the model and acquire those Steady states for the disease-free and the endemic agreement. The framework can be evaluated by reproduction number R0. We additionally clarify the numerical recreation and their outcomes.

  7. Different Epidemic Models on Complex Networks

    International Nuclear Information System (INIS)

    Zhang Haifeng; Small, Michael; Fu Xinchu

    2009-01-01

    Models for diseases spreading are not just limited to SIS or SIR. For instance, for the spreading of AIDS/HIV, the susceptible individuals can be classified into different cases according to their immunity, and similarly, the infected individuals can be sorted into different classes according to their infectivity. Moreover, some diseases may develop through several stages. Many authors have shown that the individuals' relation can be viewed as a complex network. So in this paper, in order to better explain the dynamical behavior of epidemics, we consider different epidemic models on complex networks, and obtain the epidemic threshold for each case. Finally, we present numerical simulations for each case to verify our results.

  8. Utilization of dental health care services in context of the HIV epidemic- a cross-sectional study of dental patients in the Sudan.

    Science.gov (United States)

    Nasir, Elwalid Fadul; Astrøm, Anne Nordrehaug; David, Jamil; Ali, Raouf Wahab

    2009-11-16

    HIV infected patients should be expected in the Sudanese dental health care services with an increasing frequency. Dental care utilization in the context of the HIV epidemic is generally poorly understood. Focusing on Sudanese dental patients with reported unknown HIV status, this study assessed the extent to which Andersen's model in terms of predisposing (socio-demographics), enabling (knowledge, attitudes and perceived risk related to HIV) and need related factors (oral health status) predict dental care utilization. It was hypothesized that enabling factors would add to the explanation of dental care utilization beyond that of predisposing and need related factors. Dental patients were recruited from Khartoum Dental Teaching Hospital (KDTH) and University of Science and Technology (UST) during March-July 2008. A total of 1262 patients (mean age 30.7, 56.5% females and 61% from KDTH) were examined clinically (DMFT) and participated in an interview. A total of 53.9% confirmed having attended a dental clinic for treatment at least once in the past 2 years. Logistic regression analysis revealed that predisposing factors; travelling inside Sudan (OR = 0.5) were associated with lower odds and females were associated with higher odds (OR = 2.0) for dental service utilization. Enabling factors; higher knowledge of HIV transmission (OR = 0.6) and higher HIV related experience (OR = 0.7) were associated with lower odds, whereas positive attitudes towards infected people and high perceived risk of contagion (OR = 1.3) were associated with higher odds for dental care utilization. Among need related factors dental caries experience was strongly associated with dental care utilization (OR = 4.8). Disparity in the history of dental care utilization goes beyond socio-demographic position and need for dental care. Public awareness of HIV infection control and confidence on the competence of dentists should be improved to minimize avoidance behaviour and help establish dental

  9. Epidemiological study of phylogenetic transmission clusters in a local HIV-1 epidemic reveals distinct differences between subtype B and non-B infections.

    Science.gov (United States)

    Chalmet, Kristen; Staelens, Delfien; Blot, Stijn; Dinakis, Sylvie; Pelgrom, Jolanda; Plum, Jean; Vogelaers, Dirk; Vandekerckhove, Linos; Verhofstede, Chris

    2010-09-07

    The number of HIV-1 infected individuals in the Western world continues to rise. More in-depth understanding of regional HIV-1 epidemics is necessary for the optimal design and adequate use of future prevention strategies. The use of a combination of phylogenetic analysis of HIV sequences, with data on patients' demographics, infection route, clinical information and laboratory results, will allow a better characterization of individuals responsible for local transmission. Baseline HIV-1 pol sequences, obtained through routine drug-resistance testing, from 506 patients, newly diagnosed between 2001 and 2009, were used to construct phylogenetic trees and identify transmission-clusters. Patients' demographics, laboratory and clinical data, were retrieved anonymously. Statistical analysis was performed to identify subtype-specific and transmission-cluster-specific characteristics. Multivariate analysis showed significant differences between the 59.7% of individuals with subtype B infection and the 40.3% non-B infected individuals, with regard to route of transmission, origin, infection with Chlamydia (p = 0.01) and infection with Hepatitis C virus (p = 0.017). More and larger transmission-clusters were identified among the subtype B infections (p HIV (p = 0.017). Combination of phylogenetics with demographic information, laboratory and clinical data, revealed that HIV-1 subtype B infected Caucasian men-who-have-sex-with-men with high prevalence of sexually transmitted diseases, account for the majority of local HIV-transmissions. This finding elucidates observed epidemiological trends through molecular analysis, and justifies sustained focus in prevention on this high risk group.

  10. The effect of HIV, behavioural change, and STD syndromic management on STD epidemiology in sub-Saharan Africa: simulations of Uganda

    NARCIS (Netherlands)

    E.L. Korenromp (Eline); R. Bakker (Roel); R. Gray; M.J. Wawer; D. Serwadda; J.D.F. Habbema (Dik)

    2002-01-01

    textabstractAn assessment was made of how the HIV epidemic may have influenced sexually transmitted disease (STD) epidemiology in Uganda, and how HIV would affect the effectiveness of syndromic STD treatment programmes during different stages of the epidemic. The dynamic

  11. Limited overlap between phylogenetic HIV and hepatitis C virus clusters illustrates the dynamic sexual network structure of Dutch HIV-infected MSM.

    Science.gov (United States)

    Vanhommerig, Joost W; Bezemer, Daniela; Molenkamp, Richard; Van Sighem, Ard I; Smit, Colette; Arends, Joop E; Lauw, Fanny N; Brinkman, Kees; Rijnders, Bart J; Newsum, Astrid M; Bruisten, Sylvia M; Prins, Maria; Van Der Meer, Jan T; Van De Laar, Thijs J; Schinkel, Janke

    2017-09-24

    MSM are at increased risk for infection with HIV-1 and hepatitis C virus (HCV). Is HIV/HCV coinfection confined to specific HIV transmission networks? A HIV phylogenetic tree was constructed for 5038 HIV-1 subtype B polymerase (pol) sequences obtained from MSM in the AIDS therapy evaluation in the Netherlands cohort. We investigated the existence of HIV clusters with increased HCV prevalence, the HIV phylogenetic density (i.e. the number of potential HIV transmission partners) of HIV/HCV-coinfected MSM compared with HIV-infected MSM without HCV, and the overlap in HIV and HCV phylogenies using HCV nonstructural protein 5B sequences from 183 HIV-infected MSM with acute HCV infection. Five hundred and sixty-three of 5038 (11.2%) HIV-infected MSM tested HCV positive. Phylogenetic analysis revealed 93 large HIV clusters (≥10 MSM), 370 small HIV clusters (2-9 MSM), and 867 singletons with a median HCV prevalence of 11.5, 11.6, and 9.3%, respectively. We identified six large HIV clusters with elevated HCV prevalence (range 23.5-46.2%). Median HIV phylogenetic densities for MSM with HCV (3, interquartile range 1-7) and without HCV (3, interquartile range 1-8) were similar. HCV phylogeny showed 12 MSM-specific HCV clusters (clustersize: 2-39 HCV sequences); 12.7% of HCV infections were part of the same HIV and HCV cluster. We observed few HIV clusters with elevated HCV prevalence, no increase in the HIV phylogenetic density of HIV/HCV-coinfected MSM compared to HIV-infected MSM without HCV, and limited overlap between HIV and HCV phylogenies among HIV/HCV-coinfected MSM. Our data do not support the existence of MSM-specific sexual networks that fuel both the HIV and HCV epidemic.

  12. Dynamics of Ebola epidemics in West Africa 2014 [v2; ref status: indexed, http://f1000r.es/5fh

    Directory of Open Access Journals (Sweden)

    Robin J. Evans

    2015-05-01

    Full Text Available This paper investigates the dynamics of Ebola virus transmission in West Africa during 2014. The reproduction numbers for the total period of epidemic and for different consequent time intervals are estimated based on a simple linear model. It contains one major parameter - the average infectious period that defines the dynamics of epidemics. Numerical implementations are carried out on data collected from three countries Guinea, Sierra Leone and Liberia as well as the total data collected worldwide. Predictions are provided by considering different scenarios involving the average times of infectiousness for the next few months and the end of the current epidemic is estimated according to each scenario.

  13. The importance of including dynamic social networks when modeling epidemics of airborne infections: does increasing complexity increase accuracy?

    Directory of Open Access Journals (Sweden)

    Go Myong-Hyun

    2011-07-01

    Full Text Available Abstract Mathematical models are useful tools for understanding and predicting epidemics. A recent innovative modeling study by Stehle and colleagues addressed the issue of how complex models need to be to ensure accuracy. The authors collected data on face-to-face contacts during a two-day conference. They then constructed a series of dynamic social contact networks, each of which was used to model an epidemic generated by a fast-spreading airborne pathogen. Intriguingly, Stehle and colleagues found that increasing model complexity did not always increase accuracy. Specifically, the most detailed contact network and a simplified version of this network generated very similar results. These results are extremely interesting and require further exploration to determine their generalizability. Please see related article BMC Medicine, 2011, 9:87

  14. The importance of including dynamic social networks when modeling epidemics of airborne infections: does increasing complexity increase accuracy?

    Science.gov (United States)

    Blower, Sally; Go, Myong-Hyun

    2011-07-19

    Mathematical models are useful tools for understanding and predicting epidemics. A recent innovative modeling study by Stehle and colleagues addressed the issue of how complex models need to be to ensure accuracy. The authors collected data on face-to-face contacts during a two-day conference. They then constructed a series of dynamic social contact networks, each of which was used to model an epidemic generated by a fast-spreading airborne pathogen. Intriguingly, Stehle and colleagues found that increasing model complexity did not always increase accuracy. Specifically, the most detailed contact network and a simplified version of this network generated very similar results. These results are extremely interesting and require further exploration to determine their generalizability.

  15. HIV/AIDS epidemic in French Guiana: 1979-1997. Groupe d'Etude Clinique de l'Infection VIH en Guyane Française.

    Science.gov (United States)

    Sobesky, M; Dabis, F; Le Beux, P

    2000-06-01

    The incidence of AIDS in French Guiana remains one of the highest in Latin America and the Caribbean. The annual AIDS incidence rate increased continually from the start of the epidemic until 1995, when it reached 59.3/100,000 population declining thereafter to 26.6 in 1997. The prevalence of HIV in pregnant women was 0.9% in 1993, increasing to 1.3% in 1995, and that in individuals attending sexually transmitted disease (STD) clinics was 2.1% in 1996. We included 224 patients in a study of survival after AIDS diagnosis. The principal AIDS-defining diagnosis was tuberculosis in 20.5% of reported cases. The median duration of survival was 10.2 months. Multivariate analysis showed that, patients > or = 45 years at entry progressed more rapidly to AIDS than younger patients. HIV prevention and access to health care should be developed in the various ethnic communities and adapted to cultural status. The progressive implementation of multiple antiretroviral therapies since 1996 may further reduce progression of the disease but early HIV diagnosis is required to improve the overall prognosis of HIV-infected patients.

  16. Molecular epidemiology is becoming complex under the dynamic HIV prevalence: The perspective from Harbin, China.

    Science.gov (United States)

    Shao, Bing; Song, Bo; Cao, Lijun; Du, Juan; Sun, Dongying; Lin, Yuanlong; Wang, Binyou; Wang, Fuxiang; Wang, Sunran

    2016-05-01

    Unlike most areas of China, HIV transmission via men who have sex with men (MSM) is increasing rapidly, and has become the main route of HIV transmission in Harbin city. The purpose of the current study was to elaborate the molecular epidemiologic characteristics of the new HIV epidemic. Eighty-one HIV-1 gag gene sequences (HXB2:806-1861) from local HIV infections were isolated; CRF01_AE predominated among HIV infections (71.6%), followed by subtype B (16.5%), CRF07_BC (6.2%), and unique recombinant strains (URFs; 6.2%). URFs were most often identified in the MSM population, which consisted of a recombination of CRF01_AE with subtype B or CRF07_BC. Six clusters were formed in this analysis; clusters I and II mainly circulated in southwest China. Clusters III and IV mainly circulated in southwest, southeast, and central China. Clusters V and VI mainly circulated in north and northeast China. Clusters III and IV may facilitate the transmission of the CRF01_AE strain from the southwest to the north and northeast regions of China. HIV subtypes are becoming diverse with the persistent epidemic in this geographic region. In brief, our results indicate that the molecular epidemiology of HIV is trending to be more complex. Thus, timely molecular epidemiologic supervision of HIV is necessary, especially for the MSM population. © 2015 Wiley Periodicals, Inc.

  17. Potential geographic "hotspots" for drug-injection related transmission of HIV and HCV and for initiation into injecting drug use in New York City, 2011-2015, with implications for the current opioid epidemic in the US.

    Science.gov (United States)

    Des Jarlais, D C; Cooper, H L F; Arasteh, K; Feelemyer, J; McKnight, C; Ross, Z

    2018-01-01

    We identified potential geographic "hotspots" for drug-injecting transmission of HIV and hepatitis C virus (HCV) among persons who inject drugs (PWID) in New York City. The HIV epidemic among PWID is currently in an "end of the epidemic" stage, while HCV is in a continuing, high prevalence (> 50%) stage. We recruited 910 PWID entering Mount Sinai Beth Israel substance use treatment programs from 2011-2015. Structured interviews and HIV/ HCV testing were conducted. Residential ZIP codes were used as geographic units of analysis. Potential "hotspots" for HIV and HCV transmission were defined as 1) having relatively large numbers of PWID 2) having 2 or more HIV (or HCV) seropositive PWID reporting transmission risk-passing on used syringes to others, and 3) having 2 or more HIV (or HCV) seronegative PWID reporting acquisition risk-injecting with previously used needles/syringes. Hotspots for injecting drug use initiation were defined as ZIP codes with 5 or more persons who began injecting within the previous 6 years. Among PWID, 96% injected heroin, 81% male, 34% White, 15% African-American, 47% Latinx, mean age 40 (SD = 10), 7% HIV seropositive, 62% HCV seropositive. Participants resided in 234 ZIP codes. No ZIP codes were identified as potential hotspots due to small numbers of HIV seropositive PWID reporting transmission risk. Four ZIP codes were identified as potential hotspots for HCV transmission. 12 ZIP codes identified as hotspots for injecting drug use initiation. For HIV, the lack of potential hotspots is further validation of widespread effectiveness of efforts to reduce injecting-related HIV transmission. Injecting-related HIV transmission is likely to be a rare, random event. HCV prevention efforts should include focus on potential hotspots for transmission and on hotspots for initiation into injecting drug use. We consider application of methods for the current opioid epidemic in the US.

  18. A tale of two epidemics: gender differences in socio-demographic characteristics and sexual behaviors among HIV positive individuals in Mexico City.

    Science.gov (United States)

    Bautista-Arredondo, Sergio; Servan-Mori, Edson; Beynon, Fenella; González, Andrea; Volkow, Patricia

    2015-12-16

    To date, the HIV epidemic in Mexico has been concentrated mainly among men who have sex with men, butheterosexual transmission, particularly to women, is increasingly important. This study examine gender differences in socio-demographic characteristics and risk behaviors of HIV positive individuals in Mexico City. We analyzed data from a cross-sectional survey of 1,490 clinic patients (male:female ratio 8:1) with HIV inMexico City in 2010. We examined socio-demographic characteristics, risk behavior, and history of HIV infection.From multivariate non-linear probability (probit) models we calculated predicted probabilities by sex of several outcomes: marginalization, demographic and sexual risk behaviors. Significant differences were found between men and women. Multivariate models suggest that women had lower schooling levels; were less likely to have been employed in the past month and earn more than the minimal wage; more likely to have children, to have been sexually abused, to never have used condoms and to report having been infected by a stable partner. Additionally, women were less likely to report having a partner with a history of migration to the USA and to have engaged in transactional sex. Significant differences exist between men and women with HIV in Mexico City in terms of their socioeconomicand behavioral profiles, which translate into differences in terms of exposure to HIV infection. Women face social and economic vulnerability while men tend to have riskier sexual behavior. Gender issues must be approached in prevention and treatment efforts, using diverse methods to target those most vulnerable and at risk.

  19. The 2001-03 Famine and the Dynamics of HIV in Malawi: A Natural Experiment.

    Science.gov (United States)

    Loevinsohn, Michael

    2015-01-01

    survey confirmed that there was a surge of rural-to-urban migration during the famine, particularly by women under 25 years. Migration to less affected rural areas also increased. The Malawi famine appears to have had a substantial effect on HIV's dynamics and demography. Poverty and inequality, commonly considered structural determinants of HIV epidemics, can change rapidly, apparently transmitting their effects with little lag. Epidemic patterns risk being misread if such social and economic change is ignored. Many studies examining HIV prevalence declines have implicated sexual behaviour change but do not appear to have adequately considered the contribution of rural-urban migration. The evidence from Malawi, which links actions that undermined people's food security to changes in the prevalence and distribution of HIV infections, suggests new opportunities for prevention.

  20. The 2001-03 Famine and the Dynamics of HIV in Malawi: A Natural Experiment.

    Directory of Open Access Journals (Sweden)

    Michael Loevinsohn

    household survey confirmed that there was a surge of rural-to-urban migration during the famine, particularly by women under 25 years. Migration to less affected rural areas also increased.The Malawi famine appears to have had a substantial effect on HIV's dynamics and demography. Poverty and inequality, commonly considered structural determinants of HIV epidemics, can change rapidly, apparently transmitting their effects with little lag. Epidemic patterns risk being misread if such social and economic change is ignored. Many studies examining HIV prevalence declines have implicated sexual behaviour change but do not appear to have adequately considered the contribution of rural-urban migration. The evidence from Malawi, which links actions that undermined people's food security to changes in the prevalence and distribution of HIV infections, suggests new opportunities for prevention.

  1. Impacto da terapia anti-retroviral na magnitude da epidemia do HIV/AIDS no Brasil: diversos cenários Impact of antiretroviral therapy on the magnitude of the HIV/AIDS epidemic in Brazil: various scenarios

    Directory of Open Access Journals (Sweden)

    Maria Tereza S. Barbosa

    2003-04-01

    Full Text Available Neste trabalho, utilizaram-se os algoritmos EM e EMS aplicados ao método do Cálculo Retroativo para estimar a magnitude da epidemia do HIV no Brasil. Fazendo-se suposições a respeito do comportamento dos infectados, em relação à utilização da terapia combinada das drogas anti-retrovirais, construíram-se cinco cenários para a epidemia brasileira. O objetivo foi o de ilustrar os impactos que a utilização da terapia combinada das drogas anti-retrovirais possam estar tendo ou possam vir a ter na incubação do vírus e, por conseguinte, nas avaliações da epidemia realizadas a partir dos casos de Aids notificados.We applied the back-calculation method to estimate the magnitude of the HIV epidemic in Brazil, using the EM and EMS algorithms. Under certain assumptions regarding the behavior of infected patients towards combined antiretroviral therapy, we discuss five different scenarios applied to the Brazilian epidemic. Our objective was to illustrate the impact of combined antiretroviral treatment on the incubation period and thus on estimates of the size of the HIV-infected population, based on reported AIDS cases.

  2. Dynamics of the serologic response in vaccinated and unvaccinated mumps cases during an epidemic.

    Science.gov (United States)

    Kaaijk, Patricia; Gouma, Sigrid; Hulscher, Hinke I; Han, Wanda G; Kleijne, Deborah E; van Binnendijk, Rob S; van Els, Cécile A

    2015-01-01

    In the last decade, several mumps outbreaks were reported in various countries despite high vaccination coverage. In most cases, young adults were affected who have acquired immunity against mumps solely by vaccination and not by previous wild-type mumps virus infection. To investigate mumps-specific antibody levels, functionality and dynamics during a mumps epidemic, blood samples were obtained longitudinally from 23 clinical mumps cases, with or without a prior history of vaccination, and from 20 healthy persons with no serological evidence of recent mumps virus infection. Blood samples from mumps cases were taken 1-2 months and 7-10 months after onset of disease. Both vaccinated and unvaccinated mumps cases had significantly higher geomean concentrations of mumps-specific IgG (resp. 13,617 RU/ml (95% CI of 9,574-19,367 RU/ml) vs. 1,552 (445-5412) RU/ml at 1-2 months; and 6,514 (5,247-8,088) RU/ml vs. 1,143 (480-2,725) RU/ml at 7-10 months) than healthy controls (169 (135-210) RU/ml) (p = 0.001). Patterns in virus-neutralizing (VN) antibody responses against the mumps vaccine virus were similar, vaccinated and unvaccinated mumps cases had significantly higher ND50 values at both time points of sampling (resp 4,695 (3,779-5,832) RU/ml vs. 1,533 (832-2,825) RU/ml at 1-2 months; 2,478 (1,968-3,122) RU/ml vs. 1,221 (1,029-1,449) RU/ml at 7-10 months) compared with (previously vaccinated) healthy controls (122 (196-76)) RU/ml) (p = 0.001) The unvaccinated mumps cases had significantly lower mumps-specific IgG and VN antibody concentrations at both sampling points compared with previously vaccinated cases, but their antibody concentrations did not differ significantly at the 2 time points. In contrast, the mumps-specific IgG and VN antibody concentrations of the previously vaccinated mumps cases were significantly higher within the first 2 months after onset of mumps and declined thereafter, characteristic for a secondary response. A moderate correlation was found

  3. Intersecting epidemics of HIV, HCV, and syphilis among soon-to-be released prisoners in Kyrgyzstan: Implications for prevention and treatment.

    Science.gov (United States)

    Azbel, Lyuba; Polonsky, Maxim; Wegman, Martin; Shumskaya, Natalya; Kurmanalieva, Ainura; Asanov, Akylbek; Wickersham, Jeffrey A; Dvoriak, Sergii; Altice, Frederick L

    2016-11-01

    correlated with syphilis infection. Drug injection, syphilis co-infection, and exposure to increased risk during incarceration are likely to be important contributors to HIV transmission among prisoners in Kyrgyzstan. Compared to the community, HIV is concentrated 34-fold higher in prisoners. A high proportion of undiagnosed syphilis and HIV infections presents a significant gap in the HIV care continuum. Findings highlight the critical importance of evidence-based responses within prison, including enhanced testing for HIV and sexually transmitted infections, to stem the evolving HIV epidemic in the region. Copyright © 2016. Published by Elsevier B.V.

  4. Recurrent dynamics in an epidemic model due to stimulated bifurcation crossovers

    International Nuclear Information System (INIS)

    Juanico, Drandreb Earl

    2015-01-01

    Epidemics are known to persist in the form of recurrence cycles. Despite intervention efforts through vaccination and targeted social distancing, peaks of activity for infectious diseases like influenza reappear over time. Analysis of a stochastic model is here undertaken to explore a proposed cycle-generating mechanism – the bifurcation crossover. Time series from simulations of the model exhibit oscillations similar to the temporal signature of influenza activity. Power-spectral density indicates a resonant frequency, which corresponds to the annual seasonality of influenza in temperate zones. The study finds that intervention actions influence the extinguishability of epidemic activity. Asymptotic solution to a backward Kolmogorov equation corresponds to a mean extinction time that is a function of both intervention efficacy and population size. Intervention efficacy must be greater than a certain threshold to increase the chances of extinguishing the epidemic. Agreement of the model with several phenomenological features of epidemic cycles lends to it a tractability that may serve as early warning of imminent outbreaks

  5. Recurrent dynamics in an epidemic model due to stimulated bifurcation crossovers

    Energy Technology Data Exchange (ETDEWEB)

    Juanico, Drandreb Earl [Department of Mathematics, Ateneo de Manila University, Loyola Heights, Quezon City, Philippines 1108 (Philippines); National Institute of Physics, University of the Philippines, Diliman, Quezon City, Philippines 1101 (Philippines)

    2015-05-15

    Epidemics are known to persist in the form of recurrence cycles. Despite intervention efforts through vaccination and targeted social distancing, peaks of activity for infectious diseases like influenza reappear over time. Analysis of a stochastic model is here undertaken to explore a proposed cycle-generating mechanism – the bifurcation crossover. Time series from simulations of the model exhibit oscillations similar to the temporal signature of influenza activity. Power-spectral density indicates a resonant frequency, which corresponds to the annual seasonality of influenza in temperate zones. The study finds that intervention actions influence the extinguishability of epidemic activity. Asymptotic solution to a backward Kolmogorov equation corresponds to a mean extinction time that is a function of both intervention efficacy and population size. Intervention efficacy must be greater than a certain threshold to increase the chances of extinguishing the epidemic. Agreement of the model with several phenomenological features of epidemic cycles lends to it a tractability that may serve as early warning of imminent outbreaks.

  6. Quality of life of people living with HIV/AIDS under the new epidemic characteristics in China and the associated factors.

    Directory of Open Access Journals (Sweden)

    Wei Sun

    Full Text Available BACKGROUND: Improvement of quality of life has been one of goals in health care for people living with HIV/AIDS (PLWHA. In China, the epidemic characteristics have changed and transmission is now most commonly sexual contact. However, the assessment of quality of life of PLWHA under new characteristics has limited reporting. This study was designed to assess the quality of life among PLWHA who contracted disease mainly via sexual contact and to clarify the associated factors. METHODS: A cross-sectional study was performed in Liaoning Province. Sample size (800 was calculated based on the fatality rate and enlarged with consideration on the loss of response. Participants were sampled by tables of random numbers among all registered PLWHA. Questionnaires pertaining to quality of life (SF-36 and related factors (demographic characteristics, social support and network, HIV/AIDS awareness, and behavior factors were distributed during December 2010-April 2011. 783 effective responses were obtained. RESULTS: The average scores of physical component summary (PCS, mental component summary (MCS, and total score (TS were 66.8±21.9 (Mean±SD, 62.2±20.9, and 64.5±20.2. General linear model analysis revealed that, in standardized estimate (β sequence, PCS was significantly associated with monthly income, perceived social support, antiretroviral therapy, transmission, and ethnicity; MCS was associated with perceived social support, antiretroviral therapy, condom use, monthly income, transmission, ethnicity, and alcohol consumption; whereas TS was associated with perceived social support, antiretroviral therapy, monthly income, transmission, condom use, and ethnicity. CONCLUSIONS: Quality of life for PLWHA who contracted HIV mainly via sexual contact was worse and both physical conditions and social integration were impacted. Under current epidemic characteristics, efforts to increase social support and enhance the implementation of supporting policy are

  7. Spatiotemporal dynamics of HIV-1 transmission in France (1999-2014) and impact of targeted prevention strategies.

    Science.gov (United States)

    Chaillon, Antoine; Essat, Asma; Frange, Pierre; Smith, Davey M; Delaugerre, Constance; Barin, Francis; Ghosn, Jade; Pialoux, Gilles; Robineau, Olivier; Rouzioux, Christine; Goujard, Cécile; Meyer, Laurence; Chaix, Marie-Laure

    2017-02-21

    Characterizing HIV-1 transmission networks can be important in understanding the evolutionary patterns and geospatial spread of the epidemic. We reconstructed the broad molecular epidemiology of HIV from individuals with primary HIV-1 infection (PHI) enrolled in France in the ANRS PRIMO C06 cohort over 15 years. Sociodemographic, geographic, clinical, biological and pol sequence data from 1356 patients were collected between 1999 and 2014. Network analysis was performed to infer genetic relationships, i.e. clusters of transmission, between HIV-1 sequences. Bayesian coalescent-based methods were used to examine the temporal and spatial dynamics of identified clusters from different regions in France. We also evaluated the use of network information to target prevention efforts. Participants were mostly Caucasian (85.9%) and men (86.7%) who reported sex with men (MSM, 71.4%). Overall, 387 individuals (28.5%) were involved in clusters: 156 patients (11.5%) in 78 dyads and 231 participants (17%) in 42 larger clusters (median size: 4, range 3-41). Compared to individuals with single PHI (n = 969), those in clusters were more frequently men (95.9 vs 83%, p turnaround time for sample processing, targeting prevention efforts based on phylogenetic monitoring may be an efficient way to deliver prevention interventions but would require near real time targeted interventions on the identified index cases and their partners.

  8. Common roots: a contextual review of HIV epidemics in black men who have sex with men across the African diaspora.

    Science.gov (United States)

    Millett, Gregorio A; Jeffries, William L; Peterson, John L; Malebranche, David J; Lane, Tim; Flores, Stephen A; Fenton, Kevin A; Wilson, Patrick A; Steiner, Riley; Heilig, Charles M

    2012-07-28

    Pooled estimates from across the African diaspora show that black men who have sex with men (MSM) are 15 times more likely to be HIV positive compared with general populations and 8·5 times more likely compared with black populations. Disparities in the prevalence of HIV infection are greater in African and Caribbean countries that criminalise homosexual activity than in those that do not criminalise such behaviour. With the exception of US and African epidemiological studies, most studies of black MSM mainly focus on outcomes associated with HIV behavioural risk rather than on prevalence, incidence, or undiagnosed infection. Nevertheless, black MSM across the African diaspora share common experiences such as discrimination, cultural norms valuing masculinity, concerns about confidentiality during HIV testing or treatment, low access to HIV drugs, threats of violence or incarceration, and few targeted HIV prevention resources. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. The epidemiology of HIV among young people in sub-Saharan Africa: know your local epidemic and its implications for prevention.

    Science.gov (United States)

    Napierala Mavedzenge, Sue; Olson, Rick; Doyle, Aoife M; Changalucha, John; Ross, David A

    2011-12-01

    Broad patterns of HIV epidemiology are frequently used to design generic HIV programs in sub-Saharan Africa. We reviewed the epidemiology of HIV among young people in sub-Saharan Africa, and explored the unique dynamics of infection in its different regions. In 2009, HIV prevalence among youth in sub-Saharan Africa was an estimated 1.4% in males and 3.4% in females, but these values mask wide variation at regional and national levels. Within countries there are further major differences in HIV prevalence, such as by sex, urban/rural location, economic status, education, or ethnic group. Within this highly nuanced context, HIV prevention programs targeting youth must consider both where new infections are occurring and where they are coming from. Given the epidemiology, one-size-fits-all HIV prevention programs are usually inappropriate at regional and national levels. Consideration of local context and risk associated with life transitions, such as leaving school or getting married, is imperative to successful programming for young people. Copyright © 2011 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  10. Phylogenetic Inference of HIV Transmission Clusters

    Directory of Open Access Journals (Sweden)

    Vlad Novitsky

    2017-10-01

    Full Text Available Better understanding the structure and dynamics of HIV transmission networks is essential for designing the most efficient interventions to prevent new HIV transmissions, and ultimately for gaining control of the HIV epidemic. The inference of phylogenetic relationships and the interpretation of results rely on the definition of the HIV transmission cluster. The definition of the HIV cluster is complex and dependent on multiple factors, including the design of sampling, accuracy of sequencing, precision of sequence alignment, evolutionary models, the phylogenetic method of inference, and specified thresholds for cluster support. While the majority of studies focus on clusters, non-clustered cases could also be highly informative. A new dimension in the analysis of the global and local HIV epidemics is the concept of phylogenetically distinct HIV sub-epidemics. The identification of active HIV sub-epidemics reveals spreading viral lineages and may help in the design of targeted interventions.HIVclustering can also be affected by sampling density. Obtaining a proper sampling density may increase statistical power and reduce sampling bias, so sampling density should be taken into account in study design and in interpretation of phylogenetic results. Finally, recent advances in long-range genotyping may enable more accurate inference of HIV transmission networks. If performed in real time, it could both inform public-health strategies and be clinically relevant (e.g., drug-resistance testing.

  11. Using Participatory System Dynamics Modeling to Examine the Local HIV Test and Treatment Care Continuum in Order to Reduce Community Viral Load.

    Science.gov (United States)

    Weeks, Margaret R; Li, Jianghong; Lounsbury, David; Green, Helena Danielle; Abbott, Maryann; Berman, Marcie; Rohena, Lucy; Gonzalez, Rosely; Lang, Shawn; Mosher, Heather

    2017-12-01

    Achieving community-level goals to eliminate the HIV epidemic requires coordinated efforts through community consortia with a common purpose to examine and critique their own HIV testing and treatment (T&T) care system and build effective tools to guide their efforts to improve it. Participatory system dynamics (SD) modeling offers conceptual, methodological, and analytical tools to engage diverse stakeholders in systems conceptualization and visual mapping of dynamics that undermine community-level health outcomes and identify those that can be leveraged for systems improvement. We recruited and engaged a 25-member multi-stakeholder Task Force, whose members provide or utilize HIV-related services, to participate in SD modeling to examine and address problems of their local HIV T&T service system. Findings from the iterative model building sessions indicated Task Force members' increasingly complex understanding of the local HIV care system and demonstrated their improved capacity to visualize and critique multiple models of the HIV T&T service system and identify areas of potential leverage. Findings also showed members' enhanced communication and consensus in seeking deeper systems understanding and options for solutions. We discuss implications of using these visual SD models for subsequent simulation modeling of the T&T system and for other community applications to improve system effectiveness. © Society for Community Research and Action 2017.

  12. Developing a Dynamic Pharmacophore Model for HIV-1 Integrase

    International Nuclear Information System (INIS)

    Carlson, Heather A.; Masukawa, Keven M.; Rubins, Kathleen; Bushman, Frederic; Jorgensen, William L.; Lins, Roberto; Briggs, James; Mccammon, Andy

    2000-01-01

    We present the first receptor-based pharmacophore model for HIV-1 integrase. The development of ''dynamic'' pharmacophore models is a new method that accounts for the inherent flexibility of the active site and aims to reduce the entropic penalties associated with binding a ligand. Furthermore, this new drug discovery method overcomes the limitation of an incomplete crystal structure of the target protein. A molecular dynamics (MD) simulation describes the flexibility of the uncomplexed protein. Many conformational models of the protein are saved from the MD simulations and used in a series of multi-unit search for interacting conformers (MUSIC) simulations. MUSIC is a multiple-copy minimization method, available in the BOSS program; it is used to determine binding regions for probe molecules containing functional groups that complement the active site. All protein conformations from the MD are overlaid, and conserved binding regions for the probe molecules are identified. Those conserved binding regions define the dynamic pharmacophore model. Here, the dynamic model is compared to known inhibitors of the integrase as well as a three-point, ligand-based pharmacophore model from the literature. Also, a ''static'' pharmacophore model was determined in the standard fashion, using a single crystal structure. Inhibitors thought to bind in the active site of HIV-1 integrase fit the dynamic model but not the static model. Finally, we have identified a set of compounds from the Available Chemicals Directory that fit the dynamic pharmacophore model, and experimental testing of the compounds has confirmed several new inhibitors

  13. The impact of pre-exposure prophylaxis (PrEP) on HIV epidemics in Africa and India: A simulation study

    NARCIS (Netherlands)

    D.C.J. Vissers (Debby); H.A.C.M. Voeten (Hélène); N.J.D. Nagelkerke (Nico); J.D.F. Habbema (Dik); S.J. de Vlas (Sake)

    2008-01-01

    textabstractBackground: Pre-exposure prophylaxis (PrEP) is a promising new HIV prevention method, especially for women. An urgent demand for implementation of PrEP is expected at the moment efficacy has been demonstrated in clinical trials. We explored the long-term impact of PrEP on HIV

  14. Where are we heading with HIV / AIDS in sub-Saharan Africa? The status and trends of HIV / AIDS / STD epidemics.

    Science.gov (United States)

    Kerkhoven, R

    1998-02-01

    By the end of 1997, an estimated 20.8 million people in sub-Saharan Africa were infected with HIV, 68% of all HIV infections. At the Tenth Annual International Conference on STDs and AIDS in Africa held in Abidjan in 1997, the MAP network continued its series of pre-conference symposia on the shape and status of HIV/AIDS in the various continents. The outcome of the Abidjan symposium was then published in a provisional report made available to the main conference's participants. The main conclusions of the symposium with regard to the following areas and subjects are presented: West Africa, Central Africa, the Horn of Africa, Eastern Africa, Southern Africa, life expectancy, HIV/AIDS and STDs, data, determinants of the spread of HIV, the relative importance of determinants, poverty, understanding determinants, the national response, children and the spread of HIV, and the future.

  15. An age-structured model for the coupled dynamics of HIV and HSV-2.

    Science.gov (United States)

    Kapitanov, Georgi; Alvey, Christina; Vogt-Geisse, Katia; Feng, Zhilan

    2015-08-01

    Evidence suggests a strong correlation between the prevalence of HSV-2 (genital herpes) and the perseverance of the HIV epidemic. HSV-2 is an incurable viral infection, characterized by periodic reactivation. We construct a model of the co-infection dynamics between the two diseases by incorporating a time-since-infection variable to track the alternating periods of infectiousness of HSV-2. The model considers only heterosexual relationships and distinguishes three population groups: males, general population females, and female sex workers. We calculate the basic reproduction numbers for each disease that provide threshold conditions, which determine whether a disease dies out or becomes endemic in the absence of the other disease. We also derive the invasion reproduction numbers that determine whether or not a disease can invade into a population in which the other disease is endemic. The calculations of the invasion reproduction numbers suggest a new aspect in their interpretation - the class from which the initial disease carrier arises is important for understanding the invasion dynamics and biological interpretation of the expressions of the reproduction numbers. Sensitivity analysis is conducted to examine the role of model parameters in influencing the model outcomes. The results are discussed in the last section.

  16. Impact of male circumcision on the HIV epidemic in Papua New Guinea: a country with extensive foreskin cutting practices.

    Directory of Open Access Journals (Sweden)

    Richard T Gray

    Full Text Available The degree to which adult medical male circumcision (MC programs can reduce new HIV infections in a moderate HIV prevalence country like Papua New Guinea (PNG are uncertain especially given the widespread prevalence of longitudinal foreskin cuts among adult males. We estimated the likely impact of a medical MC intervention in PNG using a mathematical model of HIV transmission. The model was age-structured and incorporated separate components for sex, rural/urban, men who have sex with men and female sex workers. Country-specific data of the prevalence of foreskin cuts, sexually transmitted infections, condom usage, and the acceptability of MC were obtained by our group through related studies. If longitudinal foreskin cutting has a protective efficacy of 20% compared to 60% for MC, then providing MC to 20% of uncut males from 2012 would require 376,000 procedures, avert 7,900 HIV infections by 2032, and require 143 MC per averted infection. Targeting uncut urban youths would achieve the most cost effective returns of 54 MC per HIV infection averted. These numbers of MC required to avert an HIV infection change little even with coverage up to 80% of men. The greater the protective efficacy of longitudinal foreskin cuts against HIV acquisition, the less impact MC interventions will have. Dependent on this efficacy, increasing condom use could have a much greater impact with a 10 percentage point increase averting 18,400 infections over this same period. MC programs could be effective in reducing HIV infections in PNG, particularly in high prevalence populations. However the overall impact is highly dependent on the protective efficacy of existing longitudinal foreskin cutting in preventing HIV.

  17. Predictors of Bisexual Behaviour among MSM Attending Intervention Sites May Help in Prevention Interventions for This Bridge to the Heterosexual Epidemic in India: Data from HIV Sentinel Surveillance

    Science.gov (United States)

    Godbole, Sheela; Sane, Suvarna; Kamble, Pranil; Raj, Yujwal; Dulhani, Nisha; Venkatesh, Srinivasan; Reddy, D. C. S.; Chavan, Laxmikant; Bhattacharya, Madhulekha; Bindoria, Suchitra; Kadam, Dilip; Thakur, Savita; Narwani, Prakash; Pereira, Elmira; Paranjape, Ramesh; Risbud, Arun

    2014-01-01

    Background Indian cultural tradition demanding marriage, many MSM howsoever they self-identify are likely to be married or have sex with women. To consolidate India's HIV prevention gains, it is important to understand and address the interaction between the MSM and heterosexual epidemics in India and create specific interventions for bisexual MSM. The challenge is to identify and intervene this hard to reach population. Data from HIV Sentinel Surveillance 2011 among MSM in four Indian states were analyzed to assess predictors and prevalence of bisexual behaviour in MSM. Methods Between March-May 2011, 4682 men (15–49 years) who had anal/oral sex with a male partner in the past month, attending intervention sites and consenting for an un-linked anonymous survey answered an 11- item questionnaire and provided blood for HIV test by finger stick at 19 designated surveillance sites. Results Of 4682 MSM tested overall, 5% were illiterate, 51% reported only receptive anal intercourse, 21% only penetrative and 28% both. 36% MSM had ever received money for sex. Overall 6.8% were HIV infected. 44% MSM were bisexual in the last six months. On multivariate analysis, ‘being bisexual’ was found to be independently associated with ‘older age’: 26–30 years [AOR = 3.1, 95% CI(2.7, 3.7)], >30 years [AOR = 6.5, 95% CI(5.5, 7.7)]; ‘reporting penetrative behaviour alone’ with other men [AOR = 5.8, 95% CI(4.8, 7.0), pbehaviour’ [AOR = 2.7, 95% CI(2.3, 3.1) pbehaviour with other men, could help in reaching this population. PMID:25211511

  18. Analysis of the epidemiological dynamics during the 1982-1983 epidemic of foot-and-mouth disease in Denmark based on molecular high-resolution strain identification

    DEFF Research Database (Denmark)

    Christensen, Laurids Siig; Normann, Preben; Thykier-Nielsen, Søren

    2005-01-01

    An epidemic of foot-and-mouth disease (FMD) causing a total of 23 cases in 1982-1983, primarily on the island of Funen, Denmark, was subjected to molecular epidemiological investigations. In an attempt to exploit the quasi-species nature of foot-and-mouth disease virus strains for molecular high......-resolution strain identification in order to analyse the dynamics of this epidemic, full-length VP1 coding regions were sequenced for 17 isolates collected at different farms during the epidemic. The sequence information together with epidemiological information gathered during the epidemic suggests......, and the prerequisite of co- or superinfection of animals with variant strains in turn implies that they have a common source or epidemiologically related sources originating from an area with endemic FMD....

  19. An estimate of the magnitude and trend of HIV/AIDS epidemic using data from the routine VCT services as an alternative data source to ANC sentinel surveillance in Addis Ababa, Ethiopia.

    Science.gov (United States)

    Getachew, Yehenew; Gotu, Butte; Enquselassie, Fikre

    2010-10-01

    Since early 1980s when AIDS was first recognized, there has been uncertainty about the future trend and the ultimate dimensions of the pandemic. This uncertainty persists because of difficulties in measuring HIV incidence and prevalence with a substantial degree of precision in a given population. One of the many factors for the lack of precision is the problem of obtaining representative data sources that can be extrapolated to the general population. National and regional HIV estimates for Ethiopia are derived from ANC based HIV surveillance data. Alternative data sources have not been exhaustively explored as potential tools to monitor the trend of HIV/ AIDS epidemic in the country. To estimate the magnitude and trend of HIV/AIDS epidemic using data from the routine VCT services as an alternative data source to ANC sentinel surveillance data. The study used secondary data sources from all government, private and NGO VCT centers, of the period of 2003-2005 in Addis Ababa. For the purpose of making comparative analysis of the VCT based estimations and projections, records of all five sentinel sites in Addis Ababa for the period 1983-2003 were reviewed. Both ANC and VCT data sources showed similar and regular trends from the beginning of the HIV epidemic till the year 1995 where the ANC showed a relatively higher prevalence rates than VCT data, with a maximum difference in HIV prevalence of 1.06% in 1993. However, a higher HIV prevalence was noted for the VCT than the ANC data source for the period of 1996-2002, with a maximum difference of 1.4% in 1998, the year when both the ANC and VCT modeled HIV prevalence reached the highest peak in Addis Ababa. On the contrary, the ANC based prevalence was higher than the VCT data for the period 2004-2010, with a maximum difference of 2.2%. This study suggests that VCT based HIV prevalence data closely approximates the ANC based data. Therefore VCT data source can be valuable to complement the ANC data in monitoring the HIV

  20. Heterogeneity of the HIV epidemic in agrarian, trading, and fishing communities in Rakai, Uganda: an observational epidemiological study.

    Science.gov (United States)

    Chang, Larry W; Grabowski, Mary K; Ssekubugu, Robert; Nalugoda, Fred; Kigozi, Godfrey; Nantume, Betty; Lessler, Justin; Moore, Sean M; Quinn, Thomas C; Reynolds, Steven J; Gray, Ronald H; Serwadda, David; Wawer, Maria J

    2016-08-01

    Understanding the extent to which HIV burden differs across communities and the drivers of local disparities is crucial for an effective and targeted HIV response. We assessed community-level variations in HIV prevalence, risk factors, and treatment and prevention service uptake in Rakai, Uganda. The Rakai Community Cohort Study (RCCS) is an open, population-based cohort of people aged 15-49 years in 40 communities. Participants are HIV tested and interviewed to obtain sociodemographic, behavioural, and health information. RCCS data from Aug 10, 2011, to May 30, 2013, were used to classify communities as agrarian (n=27), trading (n=9), or lakeside fishing sites (n=4). We mapped HIV prevalence with Bayesian methods, and characterised variability across and within community classifications. We also assessed differences in HIV risk factors and uptake of antiretroviral therapy and male circumcision between community types. 17 119 individuals were included, 9215 (54%) of whom were female. 9931 participants resided in agrarian, 3318 in trading, and 3870 in fishing communities. Median HIV prevalence was higher in fishing communities (42%, range 38-43) than in trading (17%, 11-21) and agrarian communities (14%, 9-26). Antiretroviral therapy use was significantly lower in both men and women in fishing communities than in trading (age-adjusted prevalence risk ratio in men 0·64, 95% CI 0·44-0·97; women 0·53, 0·42-0·66) and agrarian communities (men 0·55, 0·42-0·72; women 0·65, 0·54-0·79), as was circumcision coverage among men (vs trading 0·48, 0·42-0·55; vs agrarian 0·64, 0·56-0·72). Self-reported risk behaviours were significantly higher in men than in women and in fishing communities than in other community types. Substantial heterogeneity in HIV prevalence, risk factors, and service uptake in Rakai, Uganda, emphasises the need for local surveillance and the design of targeted HIV responses. High HIV burden, risk behaviours, and low use of combination

  1. Characterizing the reproduction number of epidemics with early subexponential growth dynamics

    DEFF Research Database (Denmark)

    Chowell, Gerardo; Viboud, Cécile; Simonsen, Lone

    2016-01-01

    in the first few disease generations, before susceptible depletion sets in. In reality, outbreaks can display subexponential (i.e. polynomial) growth in the first few disease generations, owing to clustering in contact patterns, spatial effects, inhomogeneous mixing, reactive behaviour changes or other...... and simulations from mechanistic models, and provide validation against a range of empirical disease datasets. Our results suggest that subexponential growth in the early phase of an epidemic is the rule rather the exception. Mechanistic simulations show that slight modifications to the classical susceptible...

  2. Strengthening Routine Data Systems to Track the HIV Epidemic and Guide the Response in Sub-Saharan Africa.

    Science.gov (United States)

    Rice, Brian; Boulle, Andrew; Baral, Stefan; Egger, Matthias; Mee, Paul; Fearon, Elizabeth; Reniers, Georges; Todd, Jim; Schwarcz, Sandra; Weir, Sharon; Rutherford, George; Hargreaves, James

    2018-04-03

    The global HIV response has entered a new phase with the recommendation of treating all persons living with HIV with antiretroviral therapy, and with the goals of reducing new infections and AIDS-related deaths to fewer than 500,000 by 2020. This new phase has intensive data requirements that will need to utilize routine data collected through service delivery platforms to monitor progress toward these goals. With a focus on sub-Saharan African, we present the following priorities to improve the demand, supply, and use of routine HIV data: (1) strengthening patient-level HIV data systems that support continuity of clinical care and document sentinel events; (2) leveraging data from HIV testing programs; (3) using targeting data collection in communities and among clients; and (4) building capacity and promoting a culture of HIV data quality assessment and use. When fully leveraged, routine data can efficiently provide timely information at a local level to inform action, as well as provide information at scale with wide geographic coverage to strengthen estimation efforts. ©Brian Rice, Andrew Boulle, Stefan Baral, Matthias Egger, Paul Mee, Elizabeth Fearon, Georges Reniers, Jim Todd, Sandra Schwarcz, Sharon Weir, George Rutherford, James Hargreaves. Originally published in JMIR Public Health and Surveillance (http://publichealth.jmir.org), 03.04.2018.

  3. Dynamic of HIV-testing after arrival in France for migrants from sub-Saharan Africa: The role of both health and social care systems.

    Science.gov (United States)

    Limousi, Frédérike; Lert, France; Desgrées du Loû, Annabel; Dray-Spira, Rosemary; Lydié, Nathalie

    2017-01-01

    HIV testing is an important tool in the management of the HIV epidemic among key populations. We aimed to explore the dynamic of first-time HIV testing in France for sub-Saharan migrants after their arrival. ANRS-Parcours is a retrospective life-event survey conducted from 2012 to 2013 in healthcare facilities in the Paris region, among 926 sub-Saharan HIV-infected migrants and 763 non-infected migrants. After describing the time to first HIV test in France and associated circumstances, we performed a discrete-time logistic regression to analyze the influence of socioeconomic position, contact with the healthcare system and sexual behaviors, on first-time HIV testing in France in migrants who arrived after 2000. Median first-time HIV testing occurred during the second year spent in France for non-infected men and women in both groups, and during the first year for men of the HIV group. The probability of testing increased with hospitalization and pregnancy for women of both groups. For non-infected men unemployment and absence of a residence permit were associated with an increased probability of HIV testing [respectively, OR = 2.2 (1.2-4.1) and OR = 2.0 (1.1-3.5)]. Unemployment was also associated with an increased probability of first-time HIV-testing for women of the HIV group [OR: 1.7 (1.0-2.7)]. Occasional and multiple sexual relationships were associated with an increased probability of first-time testing only for HIV-infected women [OR: 2.2 (1.2-4.0) and OR = 2.4 (1.3-4.6)]. Access to first HIV testing in France is promoted by contact with the health care system and is facilitated for unemployed and undocumented migrants after arrival.However, testing should be offered more systematically and repeated in order to reduce time between HIV infection and diagnosis, especially for deprived people which are particularly vulnerable regarding HIV infection.

  4. Accumulation of MxB/Mx2-resistant HIV-1 Capsid Variants During Expansion of the HIV-1 Epidemic in Human Populations.

    Science.gov (United States)

    Wei, Wei; Guo, Haoran; Ma, Min; Markham, Richard; Yu, Xiao-Fang

    2016-06-01

    Recent studies have identified human myxovirus resistance protein 2 (MxB or Mx2) as an interferon induced inhibitor of HIV-1 replication. However, whether HIV-1 can overcome MxB restriction without compromise of viral fitness has been undefined. Here, we have discovered that naturally occurring capsid (CA) variants can render HIV-1 resistant to the activity of MxB without losing viral infectivity or the ability to escape from interferon induction. Moreover, these MxB resistant HIV-1 variants do not lose MxB recognition. Surprisingly, MxB resistant CA variants are most commonly found in the Clade C HIV-1 that is the most rapidly expanding Clade throughout the world. Accumulation of MxB resistant mutations is also observed during HIV-1 spreading in human populations. These findings support a potential role for MxB as a selective force during HIV-1 transmission and evolution. Copyright © 2016. Published by Elsevier B.V.

  5. Dynamics of an epidemic model with quarantine on scale-free networks

    Science.gov (United States)

    Kang, Huiyan; Liu, Kaihui; Fu, Xinchu

    2017-12-01

    Quarantine strategies are frequently used to control or reduce the transmission risks of epidemic diseases such as SARS, tuberculosis and cholera. In this paper, we formulate a susceptible-exposed-infected-quarantined-recovered model on a scale-free network incorporating the births and deaths of individuals. Considering that the infectivity is related to the degrees of infectious nodes, we introduce quarantined rate as a function of degree into the model, and quantify the basic reproduction number, which is shown to be dependent on some parameters, such as quarantined rate, infectivity and network structures. A theoretical result further indicates the heterogeneity of networks and higher infectivity will raise the disease transmission risk while quarantine measure will contribute to the prevention of epidemic spreading. Meanwhile, the contact assumption between susceptibles and infectives may impact the disease transmission. Furthermore, we prove that the basic reproduction number serves as a threshold value for the global stability of the disease-free and endemic equilibria and the uniform persistence of the disease on the network by constructing appropriate Lyapunov functions. Finally, some numerical simulations are illustrated to perform and complement our analytical results.

  6. Structural bridging network position is associated with HIV status in a younger Black men who have sex with men epidemic.

    Science.gov (United States)

    Shah, Nirav S; Iveniuk, James; Muth, Stephen Q; Michaels, Stuart; Jose, Jo-Anne; Laumann, Edward O; Schneider, John A

    2014-02-01

    Younger Black men who have sex with men (BMSM) ages 16-29 have the highest rates of HIV in the United States. Despite increased attention to social and sexual networks as a framework for biomedical intervention, the role of measured network positions, such as bridging and their relationship to HIV risk has received limited attention. A network sample (N = 620) of BMSM respondents (N = 154) and their MSM and transgendered person network members (N = 466) was generated through respondent driven sampling of BMSM and elicitation of their personal networks. Bridging status of each network member was determined by a constraint measure and was used to assess the relationship between this bridging and unprotected anal intercourse (UAI), sex-drug use (SDU), group sex (GS) and HIV status within the network in South Chicago. Low, moderate and high bridging was observed in 411 (66.8 %), 81 (13.2 %) and 123 (20.0 %) of the network. In addition to age and having sex with men only, moderate and high levels of bridging were associated with HIV status (aOR 3.19; 95 % CI 1.58-6.45 and aOR 3.83; 95 % CI 1.23-11.95, respectively). Risk behaviors observed including UAS, GS, and SDU were not associated with HIV status, however, they clustered together in their associations with one another. Bridging network position but not risk behavior was associated with HIV status in this network sample of younger BMSM. Socio-structural features such as position within the network may be important when implementing effective HIV prevention interventions in younger BMSM populations.

  7. Phylogenetic investigation of a statewide HIV-1 epidemic reveals ongoing and active transmission networks among men who have sex with men

    Science.gov (United States)

    Chan, Philip A.; Hogan, Joseph W.; Huang, Austin; DeLong, Allison; Salemi, Marco; Mayer, Kenneth H.; Kantor, Rami

    2015-01-01

    Background Molecular epidemiologic evaluation of HIV-1 transmission networks can elucidate behavioral components of transmission that can be targets for intervention. Methods We combined phylogenetic and statistical approaches using pol sequences from patients diagnosed 2004-2011 at a large HIV center in Rhode Island, following 75% of the state’s HIV population. Phylogenetic trees were constructed using maximum likelihood and putative transmission clusters were evaluated using latent class analyses (LCA) to determine association of cluster size with underlying demographic/behavioral characteristics. A logistic growth model was used to assess intra-cluster dynamics over time and predict “active” clusters that were more likely to harbor undiagnosed infections. Results Of 1,166 HIV-1 subtype B sequences, 31% were distributed among 114 statistically-supported, monophyletic clusters (range: 2-15 sequences/cluster). Sequences from men who have sex with men (MSM) formed 52% of clusters. LCA demonstrated that sequences from recently diagnosed (2008-2011) MSM with primary HIV infection (PHI) and other sexually transmitted infections (STIs) were more likely to form larger clusters (Odds Ratio 1.62-11.25, ppornographic stores. Four large clusters with 38 sequences (100% male, 89% MSM) had a high-probability of harboring undiagnosed infections and included younger MSM with PHI and STIs. Conclusions In this first large-scale molecular epidemiologic investigation of HIV-1 transmission in New England, sexual networks among recently diagnosed MSM with PHI and concomitant STIs contributed to ongoing transmission. Characterization of transmission dynamics revealed actively growing clusters which may be targets for intervention. PMID:26258569

  8. Dynamics and optimal control of a non-linear epidemic model with relapse and cure

    Science.gov (United States)

    Lahrouz, A.; El Mahjour, H.; Settati, A.; Bernoussi, A.

    2018-04-01

    In this work, we introduce the basic reproduction number R0 for a general epidemic model with graded cure, relapse and nonlinear incidence rate in a non-constant population size. We established that the disease free-equilibrium state Ef is globally asymptotically exponentially stable if R0 1, we proved that the system model has at least one endemic state Ee. Then, by means of an appropriate Lyapunov function, we showed that Ee is unique and globally asymptotically stable under some acceptable biological conditions. On the other hand, we use two types of control to reduce the number of infectious individuals. The optimality system is formulated and solved numerically using a Gauss-Seidel-like implicit finite-difference method.

  9. Network Firewall Dynamics and the Subsaturation Stabilization of HIV.

    Science.gov (United States)

    Khan, Bilal; Dombrowski, Kirk; Saad, Mohamed; McLean, Katherine; Friedman, Samuel

    2013-01-01

    In 2001, Friedman et al. conjectured the existence of a "firewall effect" in which individuals who are infected with HIV, but remain in a state of low infectiousness, serve to prevent the virus from spreading. To evaluate this historical conjecture, we develop a new graph-theoretic measure that quantifies the extent to which Friedman's firewall hypothesis(FH)holds in a risk network. We compute this new measure across simulated trajectories of a stochastic discrete dynamical system that models a social network of 25,000 individuals engaging in risk acts over a period of 15 years. The model's parameters are based on analyses of data collected in prior studies of the real-world risk networks of people who inject drugs (PWID) in New York City. Analysis of system trajectories reveals the structural mechanisms by which individuals with mature HIV infections tend to partition the network into homogeneous clusters (with respect to infection status) and how uninfected clusters remain relatively stable (with respect to infection status) over long stretches of time. We confirm the spontaneous emergence of network firewalls in the system and reveal their structural role in the nonspreading of HIV.

  10. Critical bioethics in the time of epidemic: The case of the criminalization of HIV/AIDS nondisclosure in Canada

    Directory of Open Access Journals (Sweden)

    Jennifer M. Kilty

    2017-01-01

    Full Text Available This article highlights the ethically uncertain and emotionally charged climate that governs the criminalization of HIV nondisclosure in Canada. Focusing on AIDS Service Organizations (ASO, we suggest that interlocutors perform critical work that helps people living with HIV/AIDS make sense of their rights and responsibilities. Semi-structured interviews with 62 ASO staff across Canada revealed this shifting landscape of HIV advocacy in the age of criminalizing HIV nondisclosure. Drawing on a critical bioethics approach that is informed by considering the role of emotion in decision-making, this article critiques the liberal model of the rational actor that is central to traditional discussions of bioethics and law. Our findings suggest that ASO workers have varying degrees of knowledge about the intricacies of legal duties of disclosure, which affect how they balance their own emotions and thoughts about nondisclosure with their professional duties to provide support and counselling. Ultimately, we argue that critical bioethics in the context of criminalization commands us to appreciate the inherently affective nature of the environment in which bioethical decisions are made.

  11. Implications of differentiated care for successful ART scale-up in a concentrated HIV epidemic in Yangon, Myanmar.

    Science.gov (United States)

    Mesic, Anita; Fontaine, Julie; Aye, Theingy; Greig, Jane; Thwe, Thin Thin; Moretó-Planas, Laura; Kliesckova, Jarmila; Khin, Khin; Zarkua, Nana; Gonzalez, Lucia; Guillergan, Erwin Lloyd; O'Brien, Daniel P

    2017-07-21

    National AIDS Programme in Myanmar has made significant progress in scaling up antiretroviral treatment (ART) services and recognizes the importance of differentiated care for people living with HIV. Indeed, long centred around the hospital and reliant on physicians, the country's HIV response is undergoing a process of successful decentralization with HIV care increasingly being integrated into other health services as part of a systematic effort to expand access to HIV treatment. This study describes implementation of differentiated care in Médecins Sans Frontières (MSF)-supported programmes and reports its outcomes. A descriptive cohort analysis of adult patients on antiretroviral treatment was performed. We assessed stability of patients as of 31 December 2014 and introduced an intervention of reduced frequency of physicians' consultations for stable patients, and fast tract ART refills. We measured a number of saved physician's visits as the result of this intervention. Main outcomes, remained under care, death, lost to follow up, treatment failure, were assessed on 31 December 2015 and reported as rates for different stable groups. On 31 December 2014, our programme counted 16, 272 adult patients enrolled in HIV care, of whom 80.34% were stable. The model allowed for an increase in the average number of patients one medical team could care for - from 745 patients in 2011 to 1, 627 in 2014 - and, thus, a reduction in the number of teams needed. An assessment of stable patients enrolled on ART one year after the implementation of the new model revealed excellent outcomes, aggregated for stable patients as 98.7% remaining in care, 0.4% dead, 0.8% lost to follow-up, 0.8% clinical treatment failure and 5.8% with immunological treatment failure. Implementation of a differentiated model reduced the number of visits between stable clients and physicians, reduced the medical resources required for treatment and enabled integrated treatment of the main co

  12. The HIV-1 epidemic in Bolivia is dominated by subtype B and CRF12_BF "family" strains.

    Science.gov (United States)

    Guimarães, Monick L; Velarde-Dunois, Ketty G; Segurondo, David; Morgado, Mariza G

    2012-01-16

    Molecular epidemiological studies of HIV-1 in South America have revealed the occurrence of subtypes B, F1 and BF1 recombinants. Even so, little information concerning the HIV-1 molecular epidemiology in Bolivia is available. In this study we performed phylogenetic analyses from samples collected in Bolivia at two different points in time over a 10 year span. We analyzed these samples to estimate the trends in the HIV subtype and recombinant forms over time. Fifty one HIV-1 positive samples were collected in Bolivia over two distinct periods (1996 and 2005). These samples were genetically characterized based on partial pol protease/reverse transcriptase (pr/rt) and env regions. Alignment and neighbor-joining (NJ) phylogenetic analyses were established from partial env (n = 37) and all pol sequences using Mega 4. The remaining 14 env sequences from 1996 were previously characterized based on HMA-env (Heteroduplex mobility assay). The Simplot v.3.5.1 program was used to verify intragenic recombination, and SplitsTree 4.0 was employed to confirm the phylogenetic relationship of the BF1 recombinant samples. Phylogenetic analysis of both env and pol regions confirmed the predominance of "pure" subtype B (72.5%) samples circulating in Bolivia and revealed a high prevalence of BF1 genotypes (27.5%). Eleven out of 14 BF1 recombinants displayed a mosaic structure identical or similar to that described for the CRF12_BF variant, one sample was classified as CRF17_BF, and two others were F1pol/Benv. No "pure" HIV-1 subtype F1 or B" variant of subtype B was detected in the present study. Of note, samples characterized as CRF12_BF-related were depicted only in 2005. HIV-1 genetic diversity in Bolivia is mostly driven by subtype B followed by BF1 recombinant strains from the CRF12_BF "family". No significant temporal changes were detected between the mid-1990s and the mid-2000s for subtype B (76.2% vs 70.0%) or BF1 recombinant (23.8% vs 30.0%) samples from Bolivia.

  13. The HIV-1 epidemic in Bolivia is dominated by subtype B and CRF12_BF "family" strains

    Directory of Open Access Journals (Sweden)

    Guimarães Monick L

    2012-01-01

    Full Text Available Abstract Background Molecular epidemiological studies of HIV-1 in South America have revealed the occurrence of subtypes B, F1 and BF1 recombinants. Even so, little information concerning the HIV-1 molecular epidemiology in Bolivia is available. In this study we performed phylogenetic analyses from samples collected in Bolivia at two different points in time over a 10 year span. We analyzed these samples to estimate the trends in the HIV subtype and recombinant forms over time. Materials and methods Fifty one HIV-1 positive samples were collected in Bolivia over two distinct periods (1996 and 2005. These samples were genetically characterized based on partial pol protease/reverse transcriptase (pr/rt and env regions. Alignment and neighbor-joining (NJ phylogenetic analyses were established from partial env (n = 37 and all pol sequences using Mega 4. The remaining 14 env sequences from 1996 were previously characterized based on HMA-env (Heteroduplex mobility assay. The Simplot v.3.5.1 program was used to verify intragenic recombination, and SplitsTree 4.0 was employed to confirm the phylogenetic relationship of the BF1 recombinant samples. Results Phylogenetic analysis of both env and pol regions confirmed the predominance of "pure" subtype B (72.5% samples circulating in Bolivia and revealed a high prevalence of BF1 genotypes (27.5%. Eleven out of 14 BF1 recombinants displayed a mosaic structure identical or similar to that described for the CRF12_BF variant, one sample was classified as CRF17_BF, and two others were F1pol/Benv. No "pure" HIV-1 subtype F1 or B" variant of subtype B was detected in the present study. Of note, samples characterized as CRF12_BF-related were depicted only in 2005. Conclusion HIV-1 genetic diversity in Bolivia is mostly driven by subtype B followed by BF1 recombinant strains from the CRF12_BF "family". No significant temporal changes were detected between the mid-1990s and the mid-2000s for subtype B (76.2% vs 70

  14. Porcine Epidemic Diarrhea in Europe: In-Detail Analyses of Disease Dynamics and Molecular Epidemiology.

    Science.gov (United States)

    Hanke, Dennis; Pohlmann, Anne; Sauter-Louis, Carola; Höper, Dirk; Stadler, Julia; Ritzmann, Mathias; Steinrigl, Adi; Schwarz, Bernd-Andreas; Akimkin, Valerij; Fux, Robert; Blome, Sandra; Beer, Martin

    2017-07-06

    Porcine epidemic diarrhea (PED) is an acute and highly contagious enteric disease of swine caused by the eponymous virus (PEDV) which belongs to the genus Alphacoronavirus within the Coronaviridae virus family. Following the disastrous outbreaks in Asia and the United States, PEDV has been detected also in Europe. In order to better understand the overall situation, the molecular epidemiology, and factors that might influence the most variable disease impact; 40 samples from swine feces were collected from different PED outbreaks in Germany and other European countries and sequenced by shot-gun next-generation sequencing. A total of 38 new PEDV complete coding sequences were generated. When compared on a global scale, all investigated sequences from Central and South-Eastern Europe formed a rather homogeneous PEDV S INDEL cluster, suggesting a recent re-introduction. However, in-detail analyses revealed two new clusters and putative ancestor strains. Based on the available background data, correlations between clusters and location, farm type or clinical presentation could not be established. Additionally, the impact of secondary infections was explored using the metagenomic data sets. While several coinfections were observed, no correlation was found with disease courses. However, in addition to the PEDV genomes, ten complete viral coding sequences from nine different data sets were reconstructed each representing new virus strains. In detail, three pasivirus A strains, two astroviruses, a porcine sapelovirus, a kobuvirus, a porcine torovirus, a posavirus, and an enterobacteria phage were almost fully sequenced.

  15. Porcine Epidemic Diarrhea in Europe: In-Detail Analyses of Disease Dynamics and Molecular Epidemiology

    Directory of Open Access Journals (Sweden)

    Dennis Hanke

    2017-07-01

    Full Text Available Porcine epidemic diarrhea (PED is an acute and highly contagious enteric disease of swine caused by the eponymous virus (PEDV which belongs to the genus Alphacoronavirus within the Coronaviridae virus family. Following the disastrous outbreaks in Asia and the United States, PEDV has been detected also in Europe. In order to better understand the overall situation, the molecular epidemiology, and factors that might influence the most variable disease impact; 40 samples from swine feces were collected from different PED outbreaks in Germany and other European countries and sequenced by shot-gun next-generation sequencing. A total of 38 new PEDV complete coding sequences were generated. When compared on a global scale, all investigated sequences from Central and South-Eastern Europe formed a rather homogeneous PEDV S INDEL cluster, suggesting a recent re-introduction. However, in-detail analyses revealed two new clusters and putative ancestor strains. Based on the available background data, correlations between clusters and location, farm type or clinical presentation could not be established. Additionally, the impact of secondary infections was explored using the metagenomic data sets. While several coinfections were observed, no correlation was found with disease courses. However, in addition to the PEDV genomes, ten complete viral coding sequences from nine different data sets were reconstructed each representing new virus strains. In detail, three pasivirus A strains, two astroviruses, a porcine sapelovirus, a kobuvirus, a porcine torovirus, a posavirus, and an enterobacteria phage were almost fully sequenced.

  16. The choice of baby feeding mode within the reality of the HIV/AIDS epidemic: health education implications.

    Science.gov (United States)

    Minnie, C S; Greeff, M

    2006-11-01

    Avoidance of breast-feeding rules out the risk of HIV-transmission, but is not the best choice for all women. Pregnant women can be empowered by health education to make an informed decision. The aims of this study were to explore and describe the factors that should be considered in health education on HIV and baby feeding as well as the perceptions and knowledge-levels of midwives and pregnant women regarding these factors. The final aim was to compile guidelines for health education to pregnant women. A quantitative survey design utilizing structured questionnaires was used. An all-inclusive sample of 17 midwives working in antenatal clinics in the Potchefstroom district in South Africa and an availability sample of 93 pregnant women visiting these clinics participated. It was found that, although the midwives have a basic knowledge of HIV and baby feeding, there are specific knowledge-gaps related to the latest trends and research. The existing knowledge of the midwives was not efficiently conveyed to the pregnant women and they were not sufficiently empowered to make an informed decision. Recommendations were formulated for nursing education and research with the focus on recommendations for practice. These guidelines include factors conducive to a positive milieu, as well as the presentation and content of health education.

  17. Assessment of epidemic projections using recent HIV survey data in South Africa: a validation analysis of ten mathematical models of HIV epidemiology in the antiretroviral therapy era

    NARCIS (Netherlands)

    Eaton, J.W.; Bacaer, N.; Bershteyn, A.; Cambiano, V.; Cori, A.; Dorrington, R.E.; Fraser, C.; Gopalappa, C.; Hontelez, J.A.; Johnson, L.F.; Klein, D.J.; Phillips, A.N.; Pretorius, C.; Stover, J.; Rehle, T.M.; Hallett, T.B.

    2015-01-01

    BACKGROUND: Mathematical models are widely used to simulate the effects of interventions to control HIV and to project future epidemiological trends and resource needs. We aimed to validate past model projections against data from a large household survey done in South Africa in 2012. METHODS: We

  18. Stochastic modeling for dynamics of HIV-1 infection using cellular automata: A review.

    Science.gov (United States)

    Precharattana, Monamorn

    2016-02-01

    Recently, the description of immune response by discrete models has emerged to play an important role to study the problems in the area of human immunodeficiency virus type 1 (HIV-1) infection, leading to AIDS. As infection of target immune cells by HIV-1 mainly takes place in the lymphoid tissue, cellular automata (CA) models thus represent a significant step in understanding when the infected population is dispersed. Motivated by these, the studies of the dynamics of HIV-1 infection using CA in memory have been presented to recognize how CA have been developed for HIV-1 dynamics, which issues have been studied already and which issues still are objectives in future studies.

  19. Gender and sexuality: emerging perspectives from the heterosexual epidemic in South Africa and implications for HIV risk and prevention

    Science.gov (United States)

    2010-01-01

    Research shows that gender power inequity in relationships and intimate partner violence places women at enhanced risk of HIV infection. Men who have been violent towards their partners are more likely to have HIV. Men's behaviours show a clustering of violent and risky sexual practices, suggesting important connections. This paper draws on Raewyn Connell's notion of hegemonic masculinity and reflections on emphasized femininities to argue that these sexual, and male violent, practices are rooted in and flow from cultural ideals of gender identities. The latter enables us to understand why men and women behave as they do, and the emotional and material context within which sexual behaviours are enacted. In South Africa, while gender identities show diversity, the dominant ideal of black African manhood emphasizes toughness, strength and expression of prodigious sexual success. It is a masculinity women desire; yet it is sexually risky and a barrier to men engaging with HIV treatment. Hegemonically masculine men are expected to be in control of women, and violence may be used to establish this control. Instead of resisting this, the dominant ideal of femininity embraces compliance and tolerance of violent and hurtful behaviour, including infidelity. The women partners of hegemonically masculine men are at risk of HIV because they lack control of the circumstances of sex during particularly risky encounters. They often present their acquiescence to their partners' behaviour as a trade off made to secure social or material rewards, for this ideal of femininity is upheld, not by violence per se, by a cultural system of sanctions and rewards. Thus, men and women who adopt these gender identities are following ideals with deep roots in social and cultural processes, and thus, they are models of behaviour that may be hard for individuals to critique and in which to exercise choice. Women who are materially and emotionally vulnerable are least able to risk experiencing

  20. Unveiling HIV dynamics among transgender women: a respondent driven sampling study in Rio de Janeiro, Brazil

    Science.gov (United States)

    Grinsztejn, Beatriz; Jalil, Emilia Moreira; Monteiro, Laylla; Velasque, Luciane; Moreira, Ronaldo I.; Garcia, Ana Cristina F.; Castro, Cristiane V.; Krüger, Alícia; Luz, Paula M.; Liu, Albert Y.; Farland, Willi Mc; Buchbinder, Susan; Veloso, Valdilea G.; Wilson, Erin C.

    2017-01-01

    Background The burden of HIV in transgender women (transwomen) in Brazil remains unknown. We aimed to estimate HIV prevalence among transwomen, and identify the factors associated with newly diagnosed HIV infections. Methods “Transcender” was a respondent driven sampling study of transwomen in Rio de Janeiro, Brazil, conducted from August 2015 to January 2016. Twelve seeds were recruited from social movements and formative phase. Eligibility criteria were: self-identification as transwomen, being 18 years of age or older, living in Rio de Janeiro or metropolitan area, and having a valid peer recruitment coupon. Participants were categorized as HIV-negative, known HIV infected, or newly diagnosed as HIV infected. Predictors of newly diagnosed HIV infections were assessed by comparing the newly diagnosed with the HIV-negative. Population estimates were adjusted using the RDSII estimator. Findings In total, 345 eligible transwomen were enrolled. The study sample was young and diverse on gender identity. Population estimates of no prior HIV testing, HIV-infection and newly diagnosed as HIV-infected were 29·1%, 32·1% and 7·0%, respectively (based on n=60 with no prior testing, n=141 HIV-infected, n=40 newly diagnosed). Syphilis, rectal chlamydia and gonorrhea infection were diagnosed in 28·9%, 14·6%, and 13·5%, respectively. Newly diagnosed HIV infections were associated with black race (22·8; 95%CI 2·9–178·9), travesti (34·1; 95%CI 5·8–200·2) or transsexual woman (41·3; 95%CI 6·3–271·2) gender identity, history of sex work (30·7; 95%CI 3·5–267·3), and history of sniffing cocaine (4·4; 95%CI 1·4–14·1). Interpretation Our results suggest that transwomen bear the largest burden of HIV among any population at risk in Brazil. The high proportion of HIV diagnosis among young participants points to the need for tailored long-term health care and prevention services in order to curb the HIV epidemic and improve the quality-of-life of

  1. Characterizing HIV epidemiology in stable couples in Cambodia, the Dominican Republic, Haiti, and India.

    Science.gov (United States)

    Chemaitelly, H; Abu-Raddad, L J

    2016-01-01

    Using a set of statistical methods and HIV mathematical models applied on nationally representative Demographic and Health Survey data, we characterized HIV serodiscordancy patterns and HIV transmission dynamics in stable couples (SCs) in four countries: Cambodia, the Dominican Republic, Haiti, and India. The majority of SCs affected by HIV were serodiscordant, and about a third of HIV-infected persons had uninfected partners. Overall, nearly two-thirds of HIV infections occurred in individuals in SCs, but only about half of these infections were due to transmissions within serodiscordant couples. The majority of HIV incidence in the population occurred through extra-partner encounters in SCs. There is similarity in HIV epidemiology in SCs between these countries and countries in sub-Saharan Africa, despite the difference in scale of epidemics. It appears that HIV epidemiology in SCs may share similar patterns globally, possibly because it is a natural 'spillover' effect of HIV dynamics in high-risk populations.

  2. Hand, Foot, and Mouth Disease in China: Modeling Epidemic Dynamics of Enterovirus Serotypes and Implications for Vaccination.

    Science.gov (United States)

    Takahashi, Saki; Liao, Qiaohong; Van Boeckel, Thomas P; Xing, Weijia; Sun, Junling; Hsiao, Victor Y; Metcalf, C Jessica E; Chang, Zhaorui; Liu, Fengfeng; Zhang, Jing; Wu, Joseph T; Cowling, Benjamin J; Leung, Gabriel M; Farrar, Jeremy J; van Doorn, H Rogier; Grenfell, Bryan T; Yu, Hongjie

    2016-02-01

    -vaccination period remained either comparable to or only slightly increased from levels prior to vaccination. The duration and strength of cross-protection following infection with EV-A71 or CV-A16 was estimated to be 9.95 wk (95% confidence interval [CI]: 3.31, 23.40) in 68% of the population (95% CI: 37%, 96%). Our predictions are limited by the necessarily short and under-sampled time series and the possible circulation of unidentified serotypes, but, nonetheless, sensitivity analyses indicate that our results are robust in predicting that the vaccine should drastically reduce incidence of EV-A71 without a substantial competitive release of CV-A16. The ability of our models to capture the observed epidemic cycles suggests that herd immunity is driving the epidemic dynamics caused by the multiple serotypes of enterovirus. Our results predict that the EV-A71 and CV-A16 serotypes provide a temporary immunizing effect against each other. Achieving high coverage rates of EV-A71 vaccination would be necessary to eliminate the ongoing transmission of EV-A71, but serotype replacement by CV-A16 following EV-A71 vaccination is likely to be transient and minor compared to the corresponding reduction in the burden of EV-A71-associated HFMD. Therefore, a mass EV-A71 vaccination program of infants and young children should provide significant benefits in terms of a reduction in overall HFMD burden.

  3. Hand, Foot, and Mouth Disease in China: Modeling Epidemic Dynamics of Enterovirus Serotypes and Implications for Vaccination.

    Directory of Open Access Journals (Sweden)

    Saki Takahashi

    2016-02-01

    post-EV-A71-vaccination period remained either comparable to or only slightly increased from levels prior to vaccination. The duration and strength of cross-protection following infection with EV-A71 or CV-A16 was estimated to be 9.95 wk (95% confidence interval [CI]: 3.31, 23.40 in 68% of the population (95% CI: 37%, 96%. Our predictions are limited by the necessarily short and under-sampled time series and the possible circulation of unidentified serotypes, but, nonetheless, sensitivity analyses indicate that our results are robust in predicting that the vaccine should drastically reduce incidence of EV-A71 without a substantial competitive release of CV-A16.The ability of our models to capture the observed epidemic cycles suggests that herd immunity is driving the epidemic dynamics caused by the multiple serotypes of enterovirus. Our results predict that the EV-A71 and CV-A16 serotypes provide a temporary immunizing effect against each other. Achieving high coverage rates of EV-A71 vaccination would be necessary to eliminate the ongoing transmission of EV-A71, but serotype replacement by CV-A16 following EV-A71 vaccination is likely to be transient and minor compared to the corresponding reduction in the burden of EV-A71-associated HFMD. Therefore, a mass EV-A71 vaccination program of infants and young children should provide significant benefits in terms of a reduction in overall HFMD burden.

  4. Analysis of recruitment and industrial human resources management for optimal productivity in the presence of the HIV/AIDS epidemic.

    Science.gov (United States)

    Okosun, Kazeem O; Makinde, Oluwole D; Takaidza, Isaac

    2013-01-01

    The aim of this paper is to analyze the recruitment effects of susceptible and infected individuals in order to assess the productivity of an organizational labor force in the presence of HIV/AIDS with preventive and HAART treatment measures in enhancing the workforce output. We consider constant controls as well as time-dependent controls. In the constant control case, we calculate the basic reproduction number and investigate the existence and stability of equilibria. The model is found to exhibit backward and Hopf bifurcations, implying that for the disease to be eradicated, the basic reproductive number must be below a critical value of less than one. We also investigate, by calculating sensitivity indices, the sensitivity of the basic reproductive number to the model's parameters. In the time-dependent control case, we use Pontryagin's maximum principle to derive necessary conditions for the optimal control of the disease. Finally, numerical simulations are performed to illustrate the analytical results. The cost-effectiveness analysis results show that optimal efforts on recruitment (HIV screening of applicants, etc.) is not the most cost-effective strategy to enhance productivity in the organizational labor force. Hence, to enhance employees' productivity, effective education programs and strict adherence to preventive measures should be promoted.

  5. HIV Transmission Dynamics Among Foreign-Born Persons in the United States.

    Science.gov (United States)

    Valverde, Eduardo E; Oster, Alexandra M; Xu, Songli; Wertheim, Joel O; Hernandez, Angela L

    2017-12-15

    In the United States (US), foreign-born persons are disproportionately affected by HIV and differ epidemiologically from US-born persons with diagnosed HIV infection. Understanding HIV transmission dynamics among foreign-born persons is important to guide HIV prevention efforts for these populations. We conducted molecular transmission network analysis to describe HIV transmission dynamics among foreign-born persons with diagnosed HIV. Using HIV-1 polymerase nucleotide sequences reported to the US National HIV Surveillance System for persons with diagnosed HIV infection during 2001-2013, we constructed a genetic distance-based transmission network using HIV-TRACE and examined the birth region of potential transmission partners in this network. Of 77,686 people, 12,064 (16%) were foreign born. Overall, 28% of foreign-born persons linked to at least one other person in the transmission network. Of potential transmission partners, 62% were born in the United States, 31% were born in the same region as the foreign-born person, and 7% were born in another region of the world. Most transmission partners of male foreign-born persons (63%) were born in the United States, whereas most transmission partners of female foreign-borns (57%) were born in their same world region. These finding suggests that a majority of HIV infections among foreign-born persons in our network occurred after immigrating to the United States. Efforts to prevent HIV infection among foreign-born persons in the United States should include information of the transmission networks in which these individuals acquire or transmit HIV to develop more targeted HIV prevention interventions.

  6. The hidden epidemic: confronting sexually transmitted diseases

    National Research Council Canada - National Science Library

    Eng, Thomas R; Butler, William T

    .... In addition, STDs increase the risk of HIV transmission. The Hidden Epidemic examines the scope of sexually transmitted infections in the United States and provides a critical assessment of the nation's response to this public health crisis...

  7. the effect of cd4 count level on the middle ear dynamics of hiv

    African Journals Online (AJOL)

    2014-01-01

    Jan 1, 2014 ... THE EFFECT OF CD4 COUNT LEVEL ON THE MIDDLE EAR DYNAMICS OF HIV INFECTED PATIENTS .... compliance and pressure values were the ones causing ... of sound wave than in the control group (non-HIV infected ...

  8. T-cell dynamics in healthy and HIV-infected individuals

    NARCIS (Netherlands)

    Vrisekoop, N.

    2007-01-01

    This thesis focuses on T-cell dynamics in healthy and both treated and untreated HIV-infected individuals. Although the progressive decline in CD4+ T-cell numbers is the hallmark of HIV infection, the mechanisms behind this depletion remain controversial. Currently the most prevailing ideas include

  9. Retention in medication-assisted treatment programs in Ukraine-Identifying factors contributing to a continuing HIV epidemic.

    Science.gov (United States)

    Dumchev, Kostyantyn; Dvoryak, Sergii; Chernova, Olena; Morozova, Olga; Altice, Frederick L

    2017-10-01

    Opioid agonist treatments (OAT) are widely-used, evidence-based strategies for treating opioid dependence and reducing HIV transmission. The positive benefits of OAT are strongly correlated with time spent in treatment, making retention a key indicator for program quality. This study assessed patient retention and associated factors in Ukraine, where OAT was first introduced in 2004. Data from clinical records of 2916 patients enrolled in OAT at thirteen sites from 2005 to 2012 were entered into an electronic monitoring system. Survival analysis methods were used to determine the probability of retention and its correlates. Twelve-month retention was 65.8%, improving from 27.7% in 2005, to 70.9% in 2011. In multivariable analyses, the correlates of retention were receiving medium and high doses of medication (compared to low doses, dropout aHR=0.57 for both medium and high doses), having not been tested for HIV and tuberculosis (compared to not being tested, dropout aHR=4.44 and 3.34, respectively), and among those who were tested-a negative TB test result (compared to receiving a positive test result, dropout aHR=0.67). Retention in Ukrainian OAT programs, especially in recent years, is comparable to other countries. The results confirm the importance of adequate OAT dosing (≥60mg of methadone, ≥8mg of buprenorphine). Higher dosing, however, will require interventions that address negative attitudes toward OAT by patients and providers. Interruption of OAT, in the case developing tuberculosis, should incorporate continuity of OAT for TB patients through integrated care delivery systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Configuring the autism epidemic

    DEFF Research Database (Denmark)

    Seeberg, Jens; Christensen, Fie Lund Lindegaard

    2017-01-01

    Autism has been described as an epidemic, but this claim is contested and may point to an awareness epidemic, i.e. changes in the definition of what autism is and more attention being invested in diagnosis leading to a rise in registered cases. The sex ratio of children diagnosed with autism...... is skewed in favour of boys, and girls with autism tend to be diagnosed much later than boys. Building and further developing the notion of ‘configuration’ of epidemics, this article explores the configuration of autism in Denmark, with a particular focus on the health system and social support to families...... with children diagnosed with autism, seen from a parental perspective. The article points to diagnostic dynamics that contribute to explaining why girls with autism are not diagnosed as easily as boys. We unfold these dynamics through the analysis of a case of a Danish family with autism....

  11. Dynamics of HIV-1 RNA Near the Plasma Membrane during Virus Assembly.

    Science.gov (United States)

    Sardo, Luca; Hatch, Steven C; Chen, Jianbo; Nikolaitchik, Olga; Burdick, Ryan C; Chen, De; Westlake, Christopher J; Lockett, Stephen; Pathak, Vinay K; Hu, Wei-Shau

    2015-11-01

    To increase our understanding of the events that lead to HIV-1 genome packaging, we examined the dynamics of viral RNA and Gag-RNA interactions near the plasma membrane by using total internal reflection fluorescence microscopy. We labeled HIV-1 RNA with a photoconvertible Eos protein via an RNA-binding protein that recognizes stem-loop sequences engineered into the viral genome. Near-UV light exposure causes an irreversible structural change in Eos and alters its emitted fluorescence from green to red. We studied the dynamics of HIV-1 RNA by photoconverting Eos near the plasma membrane, and we monitored the population of photoconverted red-Eos-labeled RNA signals over time. We found that in the absence of Gag, most of the HIV-1 RNAs stayed near the plasma membrane transiently, for a few minutes. The presence of Gag significantly increased the time that RNAs stayed near the plasma membrane: most of the RNAs were still detected after 30 min. We then quantified the proportion of HIV-1 RNAs near the plasma membrane that were packaged into assembling viral complexes. By tagging Gag with blue fluorescent protein, we observed that only a portion, ∼13 to 34%, of the HIV-1 RNAs that reached the membrane were recruited into assembling particles in an hour, and the frequency of HIV-1 RNA packaging varied with the Gag expression level. Our studies reveal the HIV-1 RNA dynamics on the plasma membrane and the efficiency of RNA recruitment and provide insights into the events leading to the generation of infectious HIV-1 virions. Nascent HIV-1 particles assemble on plasma membranes. During the assembly process, HIV-1 RNA genomes must be encapsidated into viral complexes to generate infectious particles. To gain insights into the RNA packaging and virus assembly mechanisms, we labeled and monitored the HIV-1 RNA signals near the plasma membrane. Our results showed that most of the HIV-1 RNAs stayed near the plasma membrane for only a few minutes in the absence of Gag, whereas

  12. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... causes (AIDS) are often linked and referred to as "HIV/AIDS." HIV can be transferred between people ... years, HIV is no longer a death sentence, as it was when the epidemic began. This is ...

  13. Dynamic sex roles among men who have sex with men and transmissions from primary HIV infection.

    Science.gov (United States)

    Alam, Shah Jamal; Romero-Severson, Ethan; Kim, Jong-Hoon; Emond, Gilbert; Koopman, James S

    2010-09-01

    Previous studies estimating the fraction of transmissions from persons with primary HIV have not focused on the effects of switching sex role in male homosexual populations. Such behavioral fluctuations can increase the contribution of primary HIV in the overall population. We modeled HIV transmission with 8 compartments defined by 4 behavioral groups, with different anal-insertive and anal-receptive combinations, and 2 stages of infection. We explored the effects of fluctuating behavioral categories on endemic prevalence and the fraction of transmissions from primary HIV. We varied transition rates to develop the theory on how behavioral fluctuation affects infection patterns, and we used the transition rates in a Netherlands cohort to assess overall effects in a real setting. The dynamics of change in behavior-group status over time observed in the Netherlands cohort amplifies the prevalence of infection and the fraction of transmissions from primary HIV, resulting in the highest proportions of transmissions being from people with primary HIV. Fluctuation between dual- or receptive-role periods and no-anal-sex periods mainly determines this amplification. In terms of the total transmissions, the dual-role risk group is dominant. Fluctuation between insertive and receptive roles decreases the fraction of transmissions from primary HIV, but such fluctuation is infrequently observed. The fraction of transmissions from primary HIV is considerably raised by fluctuations in insertive and receptive anal sex behaviors. This increase occurs even when primary HIV or later infection status does not influence risk behavior. Thus, it is not simply biology but also behavior patterns and social contexts that determine the fraction of transmissions from primary HIV. Moreover, each primary HIV transmission has a larger population effect than each later infection transmission because the men to whom one transmits from primary HIV carry on more chains of transmissions than the men

  14. An integrated approach to care attracts people living with HIV who use illicit drugs in an urban centre with a concentrated HIV epidemic

    Directory of Open Access Journals (Sweden)

    S. Fernando

    2016-11-01

    Full Text Available Abstract Background People living with HIV (PLHIV who are also marginalized by social and structural inequities often face barriers to accessing and adhering to HIV treatment and care. The Dr. Peter Centre (DPC is a non-profit integrated care facility with a supervised injection room that serves PLHIV experiencing multiple barriers to social and health services in Vancouver, Canada. This study examines whether the DPC is successful in drawing in PLHIV with complex health issues, including addiction. Methods Using data collected by the Longitudinal Investigations into Supportive and Ancillary health services (LISA study from July 2007 to January 2010, linked with clinical variables available through the British Columbia Centre for Excellence in HIV/AIDS Drug Treatment Program, we identified DPC and non-DPC clients with a history of injection drug use. Bivariable and multivariable logistic regression analyses compared socio-demographic and clinical characteristics of DPC clients (n = 76 and non-DPC clients (n = 482 with a history of injection drug use. Results Of the 917 LISA participants included within this analysis, 100 (10.9% reported being a DPC client, of which 76 reported a history of injection drug use. Adjusted results found that compared to non-DPC clients with a history of injection drug use, DPC-clients were more likely to be male (AOR: 4.18, 95% CI = 2.09–8.37; use supportive services daily vs. less than daily (AOR: 3.16, 95% CI = 1.79–5.61; to have been diagnosed with a mental health disorder (AOR: 2.11; 95% CI: 1.12–3.99; to have a history of interpersonal violence (AOR: 2.76; 95% CI: 1.23–6.19; and to have ever experienced ART interruption longer than 1 year (AOR: 2.39; 95% CI: 1.38–4.15. Conclusions Our analyses suggest that the DPC operating care model engages PLHIV with complex care needs, highlighting that integrated care facilities are needed to support the multiple intersecting vulnerabilities faced

  15. HIV-1 A1 Subtype Epidemic in Italy Originated from Africa and Eastern Europe and Shows a High Frequency of Transmission Chains Involving Intravenous Drug Users.

    Directory of Open Access Journals (Sweden)

    Alessia Lai

    Full Text Available Subtype A accounts for only 12% of HIV-1 infections worldwide but predominates in Russia and Former Soviet Union countries of Eastern Europe. After an early propagation via heterosexual contacts, this variant spread explosively among intravenous drug users. A distinct A1 variant predominates in Greece and Albania, which penetrated directly from Africa. Clade A1 accounts for 12.5% of non-B subtypes in Italy, being the most frequent after F1 subtype.Aim of this study was to investigate the circulation of A1 subtype in Italy and trace its origin and diffusion through phylogenetic and phylodynamic approaches.The phylogenetic analysis of 113 A1 pol sequences included in the Italian ARCA database, indicated that 71 patients (62.8% clustered within 5 clades. A higher probability to be detected in clusters was found for patients from Eastern Europe and Italy (88.9% and 60.4%, respectively compared to those from Africa (20% (p < .001. Higher proportions of clustering sequences were found in intravenous drug users with respect to heterosexuals (85.7% vs. 59.3%, p = .056 and in women with respect to men (81.4% vs. 53.2%, p < .006. Subtype A1 dated phylogeny indicated an East African origin around 1961. Phylogeographical reconstruction highlighted 3 significant groups. One involved East European and some Italian variants, the second encompassed some Italian and African strains, the latter included the majority of viruses carried by African and Italian subjects and all viral sequences from Albania and Greece.Subtype A1 originated in Central Africa and spread among East European countries in 1982. It entered Italy through three introduction events: directly from East Africa, from Albania and Greece, and from the area encompassing Moldavia and Ukraine. As in previously documented A1 epidemics of East European countries, HIV-1 A1 subtype spread in Italy in part through intravenous drug users. However, Eastern European women contributed to the penetration of

  16. Dynamics of breast milk HIV-1 RNA with unilateral mastitis or abscess.

    Science.gov (United States)

    Semrau, Katherine; Kuhn, Louise; Brooks, Daniel R; Cabral, Howard; Sinkala, Moses; Kankasa, Chipepo; Thea, Donald M; Aldrovandi, Grace M

    2013-03-01

    Mastitis and abscess in HIV-infected women increase the risk of breastfeeding transmission of HIV. Guidelines encourage women to stop breastfeeding on the affected breast and feed on the contralateral breast. However, impact of breast pathology on breast milk HIV dynamics is unknown. HIV RNA was quantified in 211 breast milk samples collected before, during, and after a clinical mastitis or an abscess diagnosis from 38 HIV-infected women participating in a Zambian breastfeeding study. HIV RNA quantity was compared between affected and unaffected breasts over time using generalized estimating equation models. A sample of 115 women without breast pathology was selected as a control group. In the affected breast, breast milk HIV RNA quantity increased from the pre- to during-pathology period by log(10) 0.45 copies per milliliter [95% confidence interval (CI): 0.16 to 0.74], and after symptom resolution, HIV RNA levels were no different from prepathology levels (log10 -0.04 copies per milliliter 95% CI: -0.33 to 0.25). In the contralateral, unaffected breast, HIV RNA quantity did not significantly increase (log(10) 0.15 copies per milliliter, 95% CI: -0.41 to 0.10). Increase was more marked in women with abscess or with a greater number of mastitis symptoms. HIV RNA was not significantly different between affected and unaffected women, except at the time of diagnosis. Breast milk HIV RNA increased modestly in the affected breast with unilateral mastitis or abscess and returned to prepathology levels with symptom resolution. Contralateral HIV RNA was not affected. Results support guidelines encouraging feeding from the contralateral breast to minimize the risk of HIV transmission associated with unilateral breast pathology.

  17. Reducing HIV infection in people who inject drugs is impossible without targeting recently-infected subjects

    OpenAIRE

    Vasylyeva, Tetyana I.; Friedman, Samuel R.; Lourenco, Jose; Gupta, Sunetra; Hatzakis, Angelos; Pybus, Oliver G.; Katzourakis, Aris; Smyrnov, Pavlo; Karamitros, Timokratis; Paraskevis, Dimitrios; Magiorkinis, Gkikas

    2016-01-01

    Objective Although our understanding of viral transmission among people who inject drugs (PWID) has improved, we still know little about when and how many times each injector transmits HIV throughout the duration of infection. We describe HIV dynamics in PWID to evaluate which preventive strategies can be efficient. Design Due to the notably scarce interventions, HIV-1 spread explosively in Russia and Ukraine in 1990s. By studying this epidemic between 1995 and 2005, we characterized...

  18. Reducing HIV infection in people who inject drugs is impossible without targeting recently-infected subjects

    OpenAIRE

    Vasylyeva, TI; Friedman, SR; Lourenco, J; Gupta, S; Hatzakis, A; Pybus, OG; Katzourakis, A; Smyrnov, P; Karamitros, T; Paraskevis, D; Magiorkinis, G

    2016-01-01

    Objective: Although our understanding on viral transmission among People Who Inject Drugs (PWID) has improved, we still know little about when and how many times each injector transmits HIV throughout the duration of infection. We describe HIV dynamics in PWID to evaluate which preventive strategies can be efficient. Design: Due to the notably scarce interventions HIV-1 spread explosively in Russia and Ukraine in 1990s. By studying this epidemic between 1995 and 2005 we characterised natu...

  19. Dynamic features of apo and bound HIV-Nef protein reveal the anti-HIV dimerization inhibition mechanism.

    Science.gov (United States)

    Moonsamy, Suri; Bhakat, Soumendranath; Soliman, Mahmoud E S

    2015-01-01

    The first account on the dynamic features of Nef or negative factor, a small myristoylated protein located in the cytoplasm believes to increase HIV-1 viral titer level, is reported herein. Due to its major role in HIV-1 pathogenicity, Nef protein is considered an emerging target in anti-HIV drug design and discovery process. In this study, comparative long-range all-atom molecular dynamics simulations were employed for apo and bound protein to unveil molecular mechanism of HIV-Nef dimerization and inhibition. Results clearly revealed that B9, a newly discovered Nef inhibitor, binds at the dimeric interface of Nef protein and caused significant separation between orthogonally opposed residues, namely Asp108, Leu112 and Gln104. Large differences in magnitudes were observed in the radius of gyration (∼1.5 Å), per-residue fluctuation (∼2 Å), C-alpha deviations (∼2 Å) which confirm a comparatively more flexible nature of apo conformation due to rapid dimeric association. Compared to the bound conformer, a more globally correlated motion in case of apo structure of HIV-Nef confirms the process of dimeric association. This clearly highlights the process of inhibition as a result of ligand binding. The difference in principal component analysis (PCA) scatter plot and per-residue mobility plot across first two normal modes further justifies the same findings. The in-depth dynamic analyses of Nef protein presented in this report would serve crucial in understanding its function and inhibition mechanisms. Information on inhibitor binding mode would also assist in designing of potential inhibitors against this important HIV target.

  20. Understanding the HIV coreceptor switch from a dynamical perspective

    Directory of Open Access Journals (Sweden)

    Kamp Christel

    2009-11-01

    Full Text Available Abstract Background The entry of HIV into its target cells is facilitated by the prior binding to the cell surface molecule CD4 and a secondary coreceptor, mostly the chemokine receptors CCR5 or CXCR4. In early infection CCR5-using viruses (R5 viruses are mostly dominant while a receptor switch towards CXCR4 occurs in about 50% of the infected individuals (X4 viruses which is associated with a progression of the disease. There are many hypotheses regarding the underlying dynamics without yet a conclusive understanding. Results While it is difficult to isolate key factors in vivo we have developed a minimal in silico model based on the approaches of Nowak and May to investigate the conditions under which the receptor switch occurs. The model allows to investigate the evolution of viral strains within a probabilistic framework along the three stages of disease from primary and latent infection to the onset of AIDS with a a sudden increase in viral load which goes along with the impairment of the immune response. The model is specifically applied to investigate the evolution of the viral quasispecies in terms of R5 and X4 viruses which directly translates into the composition of viral load and consequently the question of the coreceptor switch. Conclusion The model can explain the coreceptor switch as a result of a dynamical change in the underlying environmental conditions in the host. The emergence of X4 strains does not necessarily result in the dominance of X4 viruses in viral load which is more likely to occur in the model after some time of chronic infection. A better understanding of the conditions leading to the coreceptor switch is especially of interest as CCR5 blockers have recently been licensed as drugs which suppress R5 viruses but do not seem to necessarily induce a coreceptor switch.

  1. The global transmission network of HIV-1.

    Science.gov (United States)

    Wertheim, Joel O; Leigh Brown, Andrew J; Hepler, N Lance; Mehta, Sanjay R; Richman, Douglas D; Smith, Davey M; Kosakovsky Pond, Sergei L

    2014-01-15

    Human immunodeficiency virus type 1 (HIV-1) is pandemic, but its contemporary global transmission network has not been characterized. A better understanding of the properties and dynamics of this network is essential for surveillance, prevention, and eventual eradication of HIV. Here, we apply a simple and computationally efficient network-based approach to all publicly available HIV polymerase sequences in the global database, revealing a contemporary picture of the spread of HIV-1 within and between countries. This approach automatically recovered well-characterized transmission clusters and extended other clusters thought to be contained within a single country across international borders. In addition, previously undescribed transmission clusters were discovered. Together, these clusters represent all known modes of HIV transmission. The extent of international linkage revealed by our comprehensive approach demonstrates the need to consider the global diversity of HIV, even when describing local epidemics. Finally, the speed of this method allows for near-real-time surveillance of the pandemic's progression.

  2. O papel da mídia na prevenção do HIV/Aids e a representação da mulher no contexto da epidemia The paper of the media in the prevention of HIV/AIDS and the woman's representation in the context of the epidemic

    Directory of Open Access Journals (Sweden)

    Erli Helena Gonçalves

    2005-03-01

    Full Text Available O presente artigo questiona o papel da mídia diante da epidemia do HIV/Aids. Toda a discussão é travada à luz da bioética, tentando sempre apreender os dilemas morais subjacentes nas mensagens de prevenção do HIV/Aids. Pautar se a mídia considerou os rumos da epidemia na medida em que essa ia se modificando; refletir se as campanhas educativas do HIV/Aids ponderavam as assimetrias de gênero, a sexualidade e os processos de socialização.The present article tries to question the mission of the media before the epidemic of HIV/AIDS. The whole discussion is supposed, in the light of the bioethics, to try to apprehend the tenor of the messages transmitted in the context of the disease. To discuss if the media had considered the different ways of the epidemic while they were being modified; to think if the HIV/AIDS educative campaigns had considered the gender differences, the sexuality and the socialization process.

  3. The shape of the HIV/AIDS epidemic in Puerto Rico El estado de la epidemia de VIH/SIDA en Puerto Rico

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    Maria A. Gomez

    2000-06-01

    Full Text Available This study presents information on AIDS patients in Puerto Rico, including their general sociodemographic profile, some risk-related parameters, characteristics of vulnerable groups, and elements of the clinical spectrum of the disease. Data were analyzed from the Puerto Rico AIDS Surveillance Program and available studies about the HIV/AIDS epidemic in Puerto Rico. A total of 23 089 AIDS cases was reported to the Puerto Rico AIDS Surveillance Program from January 1981 through February 1999. The HIV/AIDS epidemic has affected mostly males and females between the ages of 30 and 49, though cases have also been reported for other age groups. The cumulative proportion of persons with AIDS who are women has increased tremendously, from 11.4% for the 1981-1986 period to 21.6% for the entire 1981-1999 period. In Puerto Rico the category of injecting drug users (IDUs accounts for the majority of the AIDS cases (52%, followed by heterosexual contact (22%, and men who have sex with men (17%. The three main diagnoses for AIDS on the island are wasting syndrome (30.7%; esophageal, bronchial, and lung candidiasis (29.4%; and Pneumocystis carinii pneumonia (26.8%. According to 1994 vital statistics for Puerto Rico, AIDS was the fourth-leading cause of death. The overall reported AIDS mortality rate was 42.0 per 100 000 persons, with the rate for males, 67.8, much higher than it was for females, 17.4. AIDS is the first cause of death among persons between 30 and 39 years old. Intense efforts are needed to better understand the epidemic in Puerto Rico and its biology, social and family impacts, and financial costs.Este estudio presenta información sobre los pacientes con sida en Puerto Rico, como su perfil sociodemográfico general, los factores de riesgo, las características de los grupos vulnerables y los elementos del espectro clínico de la enfermedad. Los datos analizados procedían del Programa de Vigilancia del sida en Puerto Rico y de estudios sobre

  4. Epidemic typhus.

    Science.gov (United States)

    Bechah, Yassina; Capo, Christian; Mege, Jean-Louis; Raoult, Didier

    2008-07-01

    Epidemic typhus is transmitted to human beings by the body louse Pediculus humanus corporis. The disease is still considered a major threat by public-health authorities, despite the efficacy of antibiotics, because poor sanitary conditions are conducive to louse proliferation. Until recently, Rickettsia prowazekii, the causal agent, was thought to be confined to human beings and their body lice. Since 1975, R prowazekii infection in human beings has been related to contact with the flying squirrel Glaucomys volans in the USA. Moreover, Brill-Zinsser disease, a relapsed form of epidemic typhus that appears as sporadic cases many years after the initial infection, is unrelated to louse infestation. Stress or a waning immune system are likely to reactivate this earlier persistent infection, which could be the source of new epidemics when conditions facilitate louse infestation. Finally, R prowazekii is a potential category B bioterrorism agent, because it is stable in dried louse faeces and can be transmitted through aerosols. An increased understanding of the pathogenesis of epidemic typhus may be useful for protection against this bacterial threat.

  5. The relationship between health policy and public health interventions: a case study of the DRIVE project to "end" the HIV epidemic among people who inject drugs in Haiphong, Vietnam.

    Science.gov (United States)

    Hammett, Theodore M; Trang, Nguyen Thu; Oanh, Khuat Thi Hai; Huong, Nguyen Thi; Giang, Le Minh; Huong, Duong Thi; Nagot, Nicolas; Des Jarlais, Don C

    2018-03-12

    We present a case study of the effects of health policies on the implementation and potential outcomes of a public health intervention, using the DRIVE project, that aims to 'end' the HIV epidemic among people who inject drugs in Haiphong, Vietnam. DRIVE's success depends on two policy transitions: (1) integration of donor-funded HIV outpatient clinics into public health clinics and expansion of social health insurance; (2) implementation of a "Renovation Plan" for substance use treatment. Interviews and focus group discussions with key informants and review of policy documents and clinic data reveal that both policy transitions are underway but face challenges. DRIVE promises to show how evolving policy affects health interventions and how advocacy based on project data can improve policy. Broad lessons include the importance of clear and consistent policies, vigorous enforcement, and adequate funding of promulgated policies.

  6. Male Partner Risk Behaviors Are Associated With Reactive Rapid HIV Antibody Tests Among Pregnant Mexican Women: Implications for Prevention of Vertical and Sexual HIV Transmission in Concentrated HIV Epidemics.

    Science.gov (United States)

    Rivero, Estela; Kendall, Tamil

    2015-01-01

    Mexico's policies on antenatal HIV testing are contradictory, and little is known about social and behavioral characteristics that increase pregnant Mexican women's risks of acquiring HIV. We analyzed the association between risk behaviors reported by pregnant women for themselves and their male partners, and women's rapid HIV antibody test results from a large national sample. Three quarters of pregnant women with a reactive test did not report risk behaviors for themselves and one third did not report risk behaviors for themselves or their male partners. In the retrospective case-control analysis, other than reporting multiple sexual partners, reactive pregnant women reported risk behaviors did not differ from nonreactive women's behaviors. However, reactive pregnant women were significantly more likely to have reported risk behaviors for male partners. Our findings support universal offer of antenatal HIV testing and suggest that HIV prevention for women should focus on reducing risk of HIV acquisition within stable relationships. Copyright © 2015 Association of Nurses in AIDS Care. Published by Elsevier Inc. All rights reserved.

  7. Epidemic modeling in complex realities.

    Science.gov (United States)

    Colizza, Vittoria; Barthélemy, Marc; Barrat, Alain; Vespignani, Alessandro

    2007-04-01

    In our global world, the increasing complexity of social relations and transport infrastructures are key factors in the spread of epidemics. In recent years, the increasing availability of computer power has enabled both to obtain reliable data allowing one to quantify the complexity of the networks on which epidemics may propagate and to envision computational tools able to tackle the analysis of such propagation phenomena. These advances have put in evidence the limits of homogeneous assumptions and simple spatial diffusion approaches, and stimulated the inclusion of complex features and heterogeneities relevant in the description of epidemic diffusion. In this paper, we review recent progresses that integrate complex systems and networks analysis with epidemic modelling and focus on the impact of the various complex features of real systems on the dynamics of epidemic spreading.

  8. HIV-1 resistance dynamics in patients failing dolutegravir maintenance monotherapy.

    Science.gov (United States)

    Wijting, Ingeborg E A; Lungu, Cynthia; Rijnders, Bart J A; van der Ende, Marchina E; Pham, Hanh T; Mesplede, Thibault; Pas, Suzan D; Voermans, Jolanda J C; Schuurman, Rob; van de Vijver, David A M C; Boers, Patrick H M; Gruters, Rob A; Boucher, Charles A B; van Kampen, Jeroen J A

    2018-03-29

    A high genetic resistance barrier to the integrase-strand-transfer-inhibitor (INSTI) dolutegravir has been reported in vitro and in vivo. We describe the dynamics of INSTI-resistance-associated-mutations (INSTI-RAMs) and mutations in the 3'-polypurine tract (3'-PPT) in relation to virological failure (VF) observed in the randomized dolutegravir maintenance monotherapy study (DOMONO, NCT02401828). From ten patients with VF plasma samples prior to start cART and during VF were used to generate Sanger sequences of integrase, the 5' terminal bases of the 3'- LTR, and the 3'-PPT. Median HIV-RNA (IQR) at VF was 3,490 (1,440-4,990) c/mL. INSTI-RAMs were detected in 4/10 patients (S230R, R263K, N155H, E92Q+N155H) and in 4/10 patients no INSTI-RAMs were detected (2/10 patients integrase sequencing was unsuccessful). The time-to-VF ranged from 4 weeks to 72 weeks. In one patient, mutations developed in the highly conserved 3'-PPT. No changes in the terminal bases of the 3'-LTR were observed. The genetic barrier to resistance is too low to justify dolutegravir maintenance monotherapy as single INSTI-RAMs are sufficient to cause VF. The large variation in time-to-VF suggests that stochastic reactivation of a pre-existing provirus containing a single INSTI-RAM is the mechanism for failure. Changes in the 3'-PPT point to a new dolutegravir resistance mechanism in vivo.

  9. The dynamics of T and B cells in lymph node during chronic HIV infection: TFH and HIV, unhappy dance partners?

    Directory of Open Access Journals (Sweden)

    Jung Joo Hong

    2016-11-01

    Full Text Available Although the dynamics of germinal center (GC formation, TFH cell recruitment to B cell follicles within lymphoid organs and changes of lymphoid tissue architecture in HIV/SIV infection have been documented, the underlying immunopathology remains unclear. Here, we summarize what is known regarding the kinetics of TFH cells and GC B cells during the course of infection as well as the potential immunopathological features associated with structural changes in the lymphoid compartment. This review also explores the implications cell dynamics in the formation and maintenance of viral reservoirs in hyperplastic follicles of secondary lymphoid organs before and after viral suppressive antiretroviral therapy.

  10. Epidemic cholera spreads like wildfire

    Science.gov (United States)

    Roy, Manojit; Zinck, Richard D.; Bouma, Menno J.; Pascual, Mercedes

    2014-01-01

    Cholera is on the rise globally, especially epidemic cholera which is characterized by intermittent and unpredictable outbreaks that punctuate periods of regional disease fade-out. These epidemic dynamics remain however poorly understood. Here we examine records for epidemic cholera over both contemporary and historical timelines, from Africa (1990-2006) and former British India (1882-1939). We find that the frequency distribution of outbreak size is fat-tailed, scaling approximately as a power-law. This pattern which shows strong parallels with wildfires is incompatible with existing cholera models developed for endemic regions, as it implies a fundamental role for stochastic transmission and local depletion of susceptible hosts. Application of a recently developed forest-fire model indicates that epidemic cholera dynamics are located above a critical phase transition and propagate in similar ways to aggressive wildfires. These findings have implications for the effectiveness of control measures and the mechanisms that ultimately limit the size of outbreaks.

  11. Beyond HIV-serodiscordance: Partnership communication dynamics that affect engagement in safer conception care.

    Directory of Open Access Journals (Sweden)

    Lynn T Matthews

    miscommunication introduced constraints to autonomous reproductive decision-making, particularly for women. Such miscommunication was common, as only 2 of 20 partnerships in our sample were mutually-disclosed with agreement across all four communication themes.Enthusiasm for safer conception programming is growing. Our findings highlight the importance of addressing gendered partnership communication regarding HIV disclosure, reproductive goals, acceptable HIV risk, and commitment, alongside technical safer conception advice. Failing to consider partnership dynamics across these domains risks limiting reach, uptake, adherence to, and retention in safer conception programming.

  12. Dynamics of Preferential Substrate Recognition in HIV-1 Protease: Redefining the Substrate Envelope

    Science.gov (United States)

    Özen, Ayşegül; Haliloğlu, Türkan; Schiffer, Celia A.

    2011-01-01

    HIV-1 protease (PR) permits viral maturation by processing the Gag and Gag-Pro-Pol polyproteins. Though HIV-1 PR inhibitors (PIs) are used in combination antiviral therapy, the emergence of drug resistance has limited their efficacy. The rapid evolution of HIV-1 necessitates the consideration of drug resistance in novel drug-design strategies. Drug-resistant HIV-1 PR variants, while no longer efficiently inhibited, continue to efficiently hydrolyze the natural viral substrates. Though highly diverse in sequence, the HIV-1 PR substrates bind in a conserved three-dimensional shape we defined as the “substrate envelope”. We previously showed that resistance mutations arise where PIs protrude beyond the substrate envelope, as these regions are crucial for drug binding but not for substrate recognition. Here, we extend this model by considering the role of protein dynamics in the interaction of HIV-1 PR with its substrates. Seven molecular dynamics simulations of PR-substrate complexes were performed to estimate the conformational flexibility of substrates in their complexes. Interdependency of the substrate-protease interactions may compensate for the variations in cleavage-site sequences, and explain how a diverse set of sequences can be recognized as substrates by the same enzyme. This diversity may be essential for regulating sequential processing of substrates. We also define a dynamic substrate envelope as a more accurate representation of PR-substrate interactions. This dynamic substrate envelope, described by a probability distribution function, is a powerful tool for drug design efforts targeting ensembles of resistant HIV-1 PR variants with the aim of developing drugs that are less susceptible to resistance. PMID:21762811

  13. The social dynamics of consent and refusal in HIV surveillance in rural South Africa.

    Science.gov (United States)

    Reynolds, Lindsey; Cousins, Thomas; Newell, Marie-Louise; Imrie, John

    2013-01-01

    In the context of low rates of participation in a prospective, population-based HIV surveillance programme, researchers at a surveillance site in rural KwaZulu-Natal, South Africa, conducted an operational study from January 2009 to February 2010, with the aim of improving participation rates, particularly in the provision of dried blood spots for the surveillance. Findings suggest, firstly, that consent to participation in the HIV surveillance is informed by the dynamics of relationality in the HIV surveillance "consent encounter." Secondly, it emerged that both fieldworkers and participants found it difficult to differentiate between HIV surveillance and HIV testing in the surveillance procedure, and tended to understand and explain giving blood under the aegis of the surveillance as an HIV test. The conflation of surveillance and testing, we argue, is not merely a semantic confusion, but reveals an important tension inherent to global health research between individual risks and benefits and collective good, or between private morality and public good. Because of these structural tensions, we suggest, the HIV surveillance consent encounter activates multiple gift economies in the collection of blood samples. Thinking beyond the complex ethical dimensions provoked by new forms of long-term surveillance and health research, we therefore suggest that deepening relations between scientists, fieldworkers, and study participants in locality deserve more careful methodological consideration and descriptive attention. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. The chemical bases of the various AIDS epidemics: recreational ...

    Indian Academy of Sciences (India)

    Why did AIDS not rise and then decline exponentially owing to antiviral immunity like all other viral epidemics? Why is AIDS not contagious? Why would only HIV carriers get AIDS who use either recreational or anti-HIV drugs or are subject to malnutrition? Why is the mortality of HIV-antibody-positives treated with anti-HIV ...

  15. Viral dynamics in primary HIV-1 infection. Karolinska Institutet Primary HIV Infection Study Group.

    Science.gov (United States)

    Lindbäck, S; Karlsson, A C; Mittler, J; Blaxhult, A; Carlsson, M; Briheim, G; Sönnerborg, A; Gaines, H

    2000-10-20

    To study the natural course of viremia during primary HIV infection (PHI). Eight patients were followed from a median of 5 days from the onset of PHI illness. Plasma HIV-1 RNA levels were measured frequently and the results were fitted to mathematical models. HIV-1 RNA levels were also monitored in nine patients given two reverse transcriptase inhibitors and a protease inhibitor after a median of 7 days from the onset of PHI illness. HIV-1 RNA appeared in the blood during the week preceding onset of PHI illness and increased rapidly during the first viremic phase, reaching a peak at a mean of 7 days after onset of illness. This was followed by a phase of rapidly decreasing levels of HIV-1 RNA to an average of 21 days after onset. Viral density continued to decline thereafter but at a 5- to 50-fold lower rate; a steady-state level was reached at a median of 2 months after onset of PHI. Peak viral density levels correlated significantly with levels measured between days 50 and 600. Initiation of antiretroviral treatment during PHI resulted in rapidly declining levels to below 50 copies/mL. This study demonstrates the kinetic phases of viremia during PHI and indicates two new contributions to the natural history of HIV-1 infection: PHI peak levels correlate with steady-state levels and HIV-1 RNA declines biphasically; an initial rapid decay is usually followed by a slow decay, which is similar to the initial changes seen with antiviral treatment.

  16. HIV sexual risk behavior and family dynamics in a Dominican tourism town.

    Science.gov (United States)

    Guilamo-Ramos, Vincent; Padilla, Mark; Cedar, Anna Lindberg; Lee, Jane; Robles, Gabriel

    2013-10-01

    Expansion of the tourism industry in the Dominican Republic has had far-reaching health consequences for the local population. Research suggests families with one or more members living in tourism areas experience heightened vulnerability to HIV/STIs due to exposure to tourism environments, which can promote behaviors such as commercial and transactional sex and elevated alcohol use. Nevertheless, little is known about how tourism contexts influence family dynamics, which, in turn, shape HIV risk. This qualitative study examined family relationships through in-depth interviews with 32 adults residing in Sosúa, an internationally known destination for sex tourism. Interviewees situated HIV risk within a context of limited employment opportunities, high rates of migration, heavy alcohol use, and separation from family. This study has implications for effective design of health interventions that make use of the role of the family to prevent HIV transmission in tourism environments.

  17. HIV Sexual Risk Behavior and Family Dynamics in a Dominican Tourism Town

    Science.gov (United States)

    Guilamo-Ramos, Vincent; Padilla, Mark; Cedar, Anna Lindberg; Lee, Jane; Robles, Gabriel

    2013-01-01

    Expansion of the tourism industry in the Dominican Republic has had far-reaching health consequences for the local population. Research suggests families with one or more members living in tourism areas experience heightened vulnerability to HIV/STIs due to exposure to tourism environments, which can promote behaviors such as commercial and transactional sex and elevated alcohol use. Nevertheless, little is known about how tourism contexts influence family dynamics, which, in turn, shape HIV risk. This qualitative study examined family relationships through in-depth interviews with 32 adults residing in Sosúa, an internationally known destination for sex tourism. Interviewees situated HIV risk within a context of limited employment opportunities, high rates of migration, heavy alcohol use, and separation from family. This study has implications for effective design of health interventions that make use of the role of the family to prevent HIV transmission in tourism environments. PMID:23436038

  18. Network Firewall Dynamics and the Subsaturation Stabilization of HIV

    Directory of Open Access Journals (Sweden)

    Bilal Khan

    2013-01-01

    individuals engaging in risk acts over a period of 15 years. The model’s parameters are based on analyses of data collected in prior studies of the real-world risk networks of people who inject drugs (PWID in New York City. Analysis of system trajectories reveals the structural mechanisms by which individuals with mature HIV infections tend to partition the network into homogeneous clusters (with respect to infection status and how uninfected clusters remain relatively stable (with respect to infection status over long stretches of time. We confirm the spontaneous emergence of network firewalls in the system and reveal their structural role in the nonspreading of HIV.

  19. The Role of Relationship Dynamics and Gender Inequalities As Barriers to HIV-Serostatus Disclosure: Qualitative Study among Women and Men Living with HIV in Durban, South Africa

    Directory of Open Access Journals (Sweden)

    Divya S. Bhatia

    2017-07-01

    Full Text Available BackgroundThis qualitative study investigated gender power inequalities as they contribute to relationship dynamics and HIV-serostatus disclosure among men and women living with HIV in Durban, South Africa. HIV serodiscordance among men and women within stable partnerships contributes to high HIV incidence in southern Africa, yet disclosure rates remain low. Given the emphasis on prevention for HIV-serodiscordant couples, this research supports the urgent need to explore how best to support couples to recognize that they are part of this priority population and to access appropriate prevention and treatment.MethodsThirty-five in-depth individual interviews were conducted with 15 HIV-positive men and 20 HIV-positive women (not couples receiving care at public-sector clinics near Durban. A structured coding scheme was developed to investigate men’s and women’s attitudes toward HIV-serostatus disclosure and behaviors of sharing (or not sharing HIV serostatus with a partner. Narratives were analyzed for barriers and facilitators of disclosure through the lens of sociocultural gender inequality, focusing on reasons for non-disclosure.ResultsAmong 35 participants: median age was 33 years (men and 30 years (women; average years since HIV diagnosis was 1 (men and 1.5 (women. Four themes related to gender inequality and HIV-serostatus disclosure emerged: (1 Men and women fear disclosing to partners due to concerns about stigma and relationship dissolution, (2 suspicions and mistrust between partners underlies decisions for non-disclosure, (3 unequal, gendered power in relationships causes differential likelihood and safety of disclosure among men and women, and (4 incomplete or implicit disclosure are strategies to navigate disclosure challenges. Findings illustrate HIV-serostatus disclosure as a complex process evolving over time, rather than a one-time event.ConclusionPartner communication about HIV serostatus is infrequent and complicated

  20. Beyond HIV-serodiscordance: Partnership communication dynamics that affect engagement in safer conception care.

    Science.gov (United States)

    Matthews, Lynn T; Burns, Bridget F; Bajunirwe, Francis; Kabakyenga, Jerome; Bwana, Mwebesa; Ng, Courtney; Kastner, Jasmine; Kembabazi, Annet; Sanyu, Naomi; Kusasira, Adrine; Haberer, Jessica E; Bangsberg, David R; Kaida, Angela

    2017-01-01

    We explored acceptability and feasibility of safer conception methods among HIV-affected couples in Uganda. We recruited HIV-positive men and women on antiretroviral therapy (ART) ('index') from the Uganda Antiretroviral Rural Treatment Outcomes cohort who reported an HIV-negative or unknown-serostatus partner ('partner'), HIV-serostatus disclosure to partner, and personal or partner desire for a child within two years. We conducted in-depth interviews with 40 individuals from 20 couples, using a narrative approach with tailored images to assess acceptability of five safer conception strategies: ART for the infected partner, pre-exposure prophylaxis (PrEP) for the uninfected partner, condomless sex timed to peak fertility, manual insemination, and male circumcision. Translated and transcribed data were analyzed using thematic analysis. 11/20 index participants were women, median age of 32.5 years, median of 2 living children, and 80% had HIV-RNA perception: Participants had disparate understandings of HIV transmission and disagreed on the acceptable level of HIV risk to meet reproductive goals. (4) Partnership commitment: Participants revealed significant discord in perceptions of partnership commitment. All four types of partnership miscommunication introduced constraints to autonomous reproductive decision-making, particularly for women. Such miscommunication was common, as only 2 of 20 partnerships in our sample were mutually-disclosed with agreement across all four communication themes. Enthusiasm for safer conception programming is growing. Our findings highlight the importance of addressing gendered partnership communication regarding HIV disclosure, reproductive goals, acceptable HIV risk, and commitment, alongside technical safer conception advice. Failing to consider partnership dynamics across these domains risks limiting reach, uptake, adherence to, and retention in safer conception programming.

  1. A Human-Centered Platform for HIV Infection Reduction in New York: Development and Usage Analysis of the Ending the Epidemic (ETE) Dashboard.

    Science.gov (United States)

    Joshi, Ashish; Amadi, Chioma; Katz, Benjamin; Kulkarni, Sarah; Nash, Denis

    2017-12-11

    Dashboards have been increasingly used in clinic-based interventions, such as clinical performance improvement and monitoring risk of hospital readmissions, and are now gaining traction in population-based interventions, especially in disease assessment. We describe the design, development, and usage analysis of a geovisualization dashboard, the Ending the Epidemic (ETE) Dashboard. The ETE dashboard is a tool developed to track New York's progress towards achieving the goal of its ETE Initiative, to reduce new HIV infections from 3000 per year to 750 per year by the end of 2020. The ETE dashboard was adapted from an existing human-centered geovisualization platform, SanaViz, an Internet-enabled, interactive app incorporating principles of human-centered design and cognitive fit theory to enhance visual exploration of population health data. Usage evaluation of the ETE geovisualization dashboard was conducted using Google Analytics over a 4-week period from March 19 to April 18, 2016. The aim was to monitor user activity and analyze traffic on the ETE dashboard using evidence-based metrics that can provide adequate feedback to enhance its utilization. Usage was characterized based on three metrics: (1) number of unique visits to each page, (2) average time on each page in seconds, and (3) page bounce rate (ie, percentage of visits where user left the site immediately after viewing just a single page). Further analysis was also conducted by cross-tabulating specific usage metrics. Of 860 sessions, 324 sessions were initiated by unique users (37.7%). The most common acquisition channels included direct source (353/860, 41.0%); followed by referral traffic (340/860, 39.5%) and organic search (134/860, 15.5%). Usage statistics indicate that for the 860 sessions initiated by both new and returning users, the average viewing time was 8 minutes, 51 seconds, and the bounce rate was 46%. These statistics reflect positive results given that prior literature estimates an

  2. A Human-Centered Platform for HIV Infection Reduction in New York: Development and Usage Analysis of the Ending the Epidemic (ETE) Dashboard

    Science.gov (United States)

    Amadi, Chioma; Katz, Benjamin; Kulkarni, Sarah; Nash, Denis

    2017-01-01

    Background Dashboards have been increasingly used in clinic-based interventions, such as clinical performance improvement and monitoring risk of hospital readmissions, and are now gaining traction in population-based interventions, especially in disease assessment. Objective We describe the design, development, and usage analysis of a geovisualization dashboard, the Ending the Epidemic (ETE) Dashboard. The ETE dashboard is a tool developed to track New York’s progress towards achieving the goal of its ETE Initiative, to reduce new HIV infections from 3000 per year to 750 per year by the end of 2020. Methods The ETE dashboard was adapted from an existing human-centered geovisualization platform, SanaViz, an Internet-enabled, interactive app incorporating principles of human-centered design and cognitive fit theory to enhance visual exploration of population health data. Usage evaluation of the ETE geovisualization dashboard was conducted using Google Analytics over a 4-week period from March 19 to April 18, 2016. The aim was to monitor user activity and analyze traffic on the ETE dashboard using evidence-based metrics that can provide adequate feedback to enhance its utilization. Usage was characterized based on three metrics: (1) number of unique visits to each page, (2) average time on each page in seconds, and (3) page bounce rate (ie, percentage of visits where user left the site immediately after viewing just a single page). Further analysis was also conducted by cross-tabulating specific usage metrics. Results Of 860 sessions, 324 sessions were initiated by unique users (37.7%). The most common acquisition channels included direct source (353/860, 41.0%); followed by referral traffic (340/860, 39.5%) and organic search (134/860, 15.5%). Usage statistics indicate that for the 860 sessions initiated by both new and returning users, the average viewing time was 8 minutes, 51 seconds, and the bounce rate was 46%. These statistics reflect positive results given

  3. Creating a National HIV Curriculum.

    Science.gov (United States)

    Spach, David H; Wood, Brian R; Karpenko, Andrew; Unruh, Kenton T; Kinney, Rebecca G; Roscoe, Clay; Nelson, John

    2016-01-01

    In recent years, the HIV care provider workforce has not kept pace with an expanding HIV epidemic. To effectively address this HIV workforce shortage, a multipronged approach is needed that includes high-quality, easily accessible, up-to-date HIV education for trainees and practicing providers. Toward this objective, the University of Washington, in collaboration with the AIDS Education and Training Center National Coordinating Resource Center, is developing a modular, dynamic curriculum that addresses the entire spectrum of the HIV care continuum. Herein, we outline the general principles, content, organization, and features of this federally funded National HIV Curriculum, which allows for longitudinal, active, self-directed learning, as well as real-time evaluation, tracking, and feedback at the individual and group level. The online curriculum, which is in development, will provide a free, comprehensive, interactive HIV training and resource tool that can support national efforts to expand and strengthen the United States HIV clinical care workforce. Copyright © 2016 Association of Nurses in AIDS Care. Published by Elsevier Inc. All rights reserved.

  4. Inferring epidemic contact structure from phylogenetic trees.

    Directory of Open Access Journals (Sweden)

    Gabriel E Leventhal

    Full Text Available Contact structure is believed to have a large impact on epidemic spreading and consequently using networks to model such contact structure continues to gain interest in epidemiology. However, detailed knowledge of the exact contact structure underlying real epidemics is limited. Here we address the question whether the structure of the contact network leaves a detectable genetic fingerprint in the pathogen population. To this end we compare phylogenies generated by disease outbreaks in simulated populations with different types of contact networks. We find that the shape of these phylogenies strongly depends on contact structure. In particular, measures of tree imbalance allow us to quantify to what extent the contact structure underlying an epidemic deviates from a null model contact network and illustrate this in the case of random mixing. Using a phylogeny from the Swiss HIV epidemic, we show that this epidemic has a significantly more unbalanced tree than would be expected from random mixing.

  5. Impulsive vaccination and dispersal on dynamics of an SIR epidemic model with restricting infected individuals boarding transports

    Science.gov (United States)

    Jiao, Jianjun; Cai, Shaohong; Li, Limei

    2016-05-01

    To understand the effect of impulsive vaccination and restricting infected individuals boarding transports on disease spread, we establish an SIR model with impulsive vaccination, impulsive dispersal and restricting infected individuals boarding transports. This SIR epidemic model for two regions, which are connected by transportation of non-infected individuals, portrays the evolvement of diseases. We prove that all solutions of the investigated system are uniformly ultimately bounded. We also prove that there exists globally asymptotically stable infection-free boundary periodic solution. The condition for permanence is discussed. It is concluded that the approach of impulsive vaccination and restricting infected individuals boarding transports provides reliable tactic basis for preventing disease spread.

  6. FRED (a Framework for Reconstructing Epidemic Dynamics): an open-source software system for modeling infectious diseases and control strategies using census-based populations.

    Science.gov (United States)

    Grefenstette, John J; Brown, Shawn T; Rosenfeld, Roni; DePasse, Jay; Stone, Nathan T B; Cooley, Phillip C; Wheaton, William D; Fyshe, Alona; Galloway, David D; Sriram, Anuroop; Guclu, Hasan; Abraham, Thomas; Burke, Donald S

    2013-10-08

    Mathematical and computational models provide valuable tools that help public health planners to evaluate competing health interventions, especially for novel circumstances that cannot be examined through observational or controlled studies, such as pandemic influenza. The spread of diseases like influenza depends on the mixing patterns within the population, and these mixing patterns depend in part on local factors including the spatial distribution and age structure of the population, the distribution of size and composition of households, employment status and commuting patterns of adults, and the size and age structure of schools. Finally, public health planners must take into account the health behavior patterns of the population, patterns that often vary according to socioeconomic factors such as race, household income, and education levels. FRED (a Framework for Reconstructing Epidemic Dynamics) is a freely available open-source agent-based modeling system based closely on models used in previously published studies of pandemic influenza. This version of FRED uses open-access census-based synthetic populations that capture the demographic and geographic heterogeneities of the population, including realistic household, school, and workplace social networks. FRED epidemic models are currently available for every state and county in the United States, and for selected international locations. State and county public health planners can use FRED to explore the effects of possible influenza epidemics in specific geographic regions of interest and to help evaluate the effect of interventions such as vaccination programs and school closure policies. FRED is available under a free open source license in order to contribute to the development of better modeling tools and to encourage open discussion of modeling tools being used to evaluate public health policies. We also welcome participation by other researchers in the further development of FRED.

  7. The HIV-poverty thesis re-examined: poverty, wealth or inequality as a social determinant of HIV infection in sub-Saharan Africa?

    Science.gov (United States)

    Fox, Ashley M

    2012-07-01

    Although health is generally believed to improve with higher wealth, research on HIV in sub-Saharan Africa has shown otherwise. Whereas researchers and advocates have frequently advanced poverty as a social determinant that can help to explain sub-Saharan Africa's disproportionate burden of HIV infection, recent evidence from population surveys suggests that HIV infection is higher among wealthier individuals. Furthermore, wealthier countries in Africa have experienced the fastest growing epidemics. Some researchers have theorized that inequality in wealth may be more important than absolute wealth in explaining why some countries have higher rates of infection and rapidly increasing epidemics. Studies taking a longitudinal approach have further suggested a dynamic process whereby wealth initially increases risk for HIV acquisition and later becomes protective. Prior studies, conducted exclusively at either the individual or the country level, have neither attempted to disentangle the effects of absolute and relative wealth on HIV infection nor to look simultaneously at different levels of analysis within countries at different stages in their epidemics. The current study used micro-, meso- and macro-level data from Demographic and Health Surveys (DHS) across 170 regions within sixteen countries in sub-Saharan Africa to test the hypothesis that socioeconomic inequality, adjusted for absolute wealth, is associated with greater risk of HIV infection. These analyses reveal that inequality trumps wealth: living in a region with greater inequality in wealth was significantly associated with increased individual risk of HIV infection, net of absolute wealth. The findings also reveal a paradox that supports a dynamic interpretation of epidemic trends: in wealthier regions/countries, individuals with less wealth were more likely to be infected with HIV, whereas in poorer regions/countries, individuals with more wealth were more likely to be infected with HIV. These

  8. How to analytically characterize the epidemic threshold within the coupled disease-behavior systems?. Comment on "Coupled disease-behavior dynamics on complex networks: A review" by Z. Wang et al.

    Science.gov (United States)

    Xia, Cheng-Yi; Ding, Shuai; Sun, Shi-Wen; Wang, Li; Gao, Zhong-Ke; Wang, Juan

    2015-12-01

    As is well known, outbreak of epidemics may drive the human population to take some necessary measures to protect themselves from not being infected by infective ones, these precautions in turn will also keep from the further spreading of infectious diseases among the population. Thus, to fully comprehend the epidemic spreading behavior within real-world systems, the interplay between disease dynamics and human behavioral and social dynamics needs to be considered simultaneously, such that some effective containment-measures can be successfully developed [1-3].

  9. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... depict the devastating consequences of compromised judgment and critical thinking that can result from drug use. Young ... HIV epidemic. As we learn more about the critical connection between drug misuse and HIV/AIDS and ...

  10. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... between drug misuse and HIV/AIDS. In the early years of the HIV epidemic, it became clear ... Children, Youth and Families The American Academy of Child & Adolescent Psychiatry (AACAP) The United Negro College Fund, ...

  11. Statistical behavior of time dynamics evolution of HIV infection

    Science.gov (United States)

    González, Ramón E. R.; Santos, Iury A. X.; Nunes, Marcos G. P.; de Oliveira, Viviane M.; Barbosa, Anderson L. R.

    2017-09-01

    We use the tools of the random matrix theory (RMT) to investigate the statistical behavior of the evolution of human immunodeficiency virus (HIV) infection. By means of the nearest-neighbor spacing distribution we have identified four distinct regimes of the evolution of HIV infection. We verified that at the beginning of the so-called clinical latency phase the concentration of infected cells grows slowly and evolves in a correlated way. This regime is followed by another one in which the correlation is lost and that in turn leads the system to a regime in which the increase of infected cells is faster and correlated. In the final phase, the one in which acquired immunodeficiency syndrome (AIDS) is stablished, the system presents maximum correlation as demonstrated by GOE distribution.

  12. Unveiling of HIV dynamics among transgender women: a respondent-driven sampling study in Rio de Janeiro, Brazil.

    Science.gov (United States)

    Grinsztejn, Beatriz; Jalil, Emilia M; Monteiro, Laylla; Velasque, Luciane; Moreira, Ronaldo I; Garcia, Ana Cristina F; Castro, Cristiane V; Krüger, Alícia; Luz, Paula M; Liu, Albert Y; McFarland, Willi; Buchbinder, Susan; Veloso, Valdilea G; Wilson, Erin C

    2017-04-01

    -care and prevention services to curb the HIV epidemic and improve the quality of life of transwomen in Brazil. Brazilian Research Council, National Institute of Allergy and Infectious Diseases, Brazilian Sexually Transmitted Disease/AIDS, and Viral Hepatitis Department of the Brazilian Ministry of Health. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. The HIV Epidemic in Sub-Saharan Africa is Aging: Evidence from the Demographic and Health Surveys in Sub-Saharan Africa.

    Science.gov (United States)

    Vollmer, Sebastian; Harttgen, Kenneth; Alfven, Tobias; Padayachy, Jude; Ghys, Peter; Bärnighausen, Till

    2017-07-01

    We use the individual-level data from all available Demographic and Health Surveys (DHS) from 27 sub-Saharan African countries conducted between 2003 and 2012 (40 population-based and nationally representative surveys in total) to calculate HIV testing consent rates and HIV prevalence for each country separately, as well as for the pooled sample. The pooled sample comprised of 427,130 individuals. In most countries HIV prevalence in adults aged 45 years and above is higher than in the total population. We further show that over the past decade HIV prevalence has increased in older age groups, while it has decreased in younger ones. While the age patterns of HIV consent rates vary across the 27 countries included in our sample, analysis of the pooled sample across all countries reveals a u-shaped relationship with lowest consent rates around age 35 years and higher consent rates among younger and older people. We argue that future DHS and other population-based HIV surveys should offer HIV testing to all adults without age limits.

  14. Substance Abuse and HIV/AIDS in the Caribbean.

    Science.gov (United States)

    Angulo-Arreola, Iliana Alexandra; Bastos, Francisco I; Strathdee, Steffanie A

    The Caribbean and Central America represent a formidable challenge for researchers and policy makers in the HIV field, due to their pronounced heterogeneity in terms of social, economic, and cultural contexts and the different courses the HIV epidemic has followed in the region. Such contrasting contexts and epidemics can be exemplified by 2 countries that share the island of Hispaniola, the French Creole-speaking Haiti, and the Spanish-speaking Dominican Republic. Haiti has experienced the worst epidemics outside of sub-Saharan Africa. Following a protracted economic and social crisis, recently aggravated by a devastating earthquake, the local HIV epidemic could experience resurgence. The region, strategically located on the way between coca-producing countries and the profitable North American markets, has been a transshipment area for years. Notwithstanding, the impact of such routes on local drug scenes has been very heterogeneous and dynamic, depending on a combination of local mores, drug enforcement activities, and the broad social and political context. Injecting drug use remains rare in the region, but local drug scenes are dynamic under the influence of increasing mobility of people and goods to and from North and South America, growing tourism and commerce, and prostitution. The multiple impacts of the recent economic and social crisis, as well as the influence of drug-trafficking routes across the Caribbean and other Latin American countries require a sustained effort to track changes in the HIV risk environment to inform sound drug policies and initiatives to minimize drug-related harms in the region.

  15. Can churches play a role in combating the HIV/AIDS epidemic? A study of the attitudes of christian religious leaders in Madagascar.

    Directory of Open Access Journals (Sweden)

    Jerry S Rakotoniana

    Full Text Available INTRODUCTION: Churches occupy an important social and cultural position in Madagascar. The sexual transmission of HIV raises controversies about the role that Churches can play in preventing HIV/AIDS. This cross-sectional survey investigated recommendations by religious leaders for condom use and other preventive strategies in the context of international guidelines. METHODS: A questionnaire was self-administered to a random sample of religious leaders. The questions related to preventive methods against HIV/AIDS such as: condom use, marital fidelity, sexual abstinence before marriage, and HIV-testing. Associations with recommendations for condom use were evaluated using univariate and multivariate logistic regression analyses. RESULTS: Of 231 religious leaders, 215 (93.1% were willing to share their knowledge of HIV/AIDS with their congregations. The majority received their information from the media (N=136, 58.9%, a minority from their church (N=9, 3.9%, and 38 (16.4% had received prior training on HIV. Nearly all (N=212, 91.8% knew that HIV could be sexually transmitted though only a few (N=39, 16.9% were aware of mother-to-child transmission or unsafe injections (N=56, 24.2%. A total of 91 (39.4% were willing to, or had recommended (N=64, 27.7%, condom use, while 50 (21.6% had undergone HIV testing. Only nine (3.9% had ever cared for a person living with HIV/AIDS (PLHIV. Multivariable logistic regression shows that condom use recommendations by religious leaders were negatively associated with tertiary level education (OR: 0.3, 95% CI 0.1-0.7, and positively associated with knowing a person at risk (OR: 16.2, 95% CI 3.2-80.2, knowing of an ART center (OR: 2.6, 95% CI 1.4-4.8, and receiving information about HIV at school (OR: 2.6, 95% CI 1.2-5.6. CONCLUSIONS: Malagasy church leaders could potentially become key players in HIV/AIDS prevention if they improved their knowledge of the illness, their commitment to international recommendations

  16. HIV/AIDS

    Science.gov (United States)

    ... Key populations are groups who are at increased risk of HIV irrespective of epidemic type or local context. They include: men who have sex with men, ... HIV testing and counselling; HIV treatment and care; risk-reduction ... management of STIs, tuberculosis and viral hepatitis. Elimination of ...

  17. Beyond Risk Compensation: Clusters of Antiretroviral Treatment (ART) Users in Sexual Networks Can Modify the Impact of ART on HIV Incidence.

    Science.gov (United States)

    Delva, Wim; Helleringer, Stéphane

    Concerns about risk compensation-increased risk behaviours in response to a perception of reduced HIV transmission risk-after the initiation of ART have largely been dispelled in empirical studies, but other changes in sexual networking patterns may still modify the effects of ART on HIV incidence. We developed an exploratory mathematical model of HIV transmission that incorporates the possibility of ART clusters, i.e. subsets of the sexual network in which the density of ART patients is much higher than in the rest of the network. Such clusters may emerge as a result of ART homophily-a tendency for ART patients to preferentially form and maintain relationships with other ART patients. We assessed whether ART clusters may affect the impact of ART on HIV incidence, and how the influence of this effect-modifying variable depends on contextual variables such as HIV prevalence, HIV serosorting, coverage of HIV testing and ART, and adherence to ART. ART homophily can modify the impact of ART on HIV incidence in both directions. In concentrated epidemics and generalized epidemics with moderate HIV prevalence (≈ 10%), ART clusters can enhance the impact of ART on HIV incidence, especially when adherence to ART is poor. In hyperendemic settings (≈ 35% HIV prevalence), ART clusters can reduce the impact of ART on HIV incidence when adherence to ART is high but few people living with HIV (PLWH) have been diagnosed. In all contexts, the effects of ART clusters on HIV epidemic dynamics are distinct from those of HIV serosorting. Depending on the programmatic and epidemiological context, ART clusters may enhance or reduce the impact of ART on HIV incidence, in contrast to serosorting, which always leads to a lower impact of ART on HIV incidence. ART homophily and the emergence of ART clusters should be measured empirically and incorporated into more refined models used to plan and evaluate ART programmes.

  18. Beyond Risk Compensation: Clusters of Antiretroviral Treatment (ART Users in Sexual Networks Can Modify the Impact of ART on HIV Incidence.

    Directory of Open Access Journals (Sweden)

    Wim Delva

    Full Text Available Concerns about risk compensation-increased risk behaviours in response to a perception of reduced HIV transmission risk-after the initiation of ART have largely been dispelled in empirical studies, but other changes in sexual networking patterns may still modify the effects of ART on HIV incidence.We developed an exploratory mathematical model of HIV transmission that incorporates the possibility of ART clusters, i.e. subsets of the sexual network in which the density of ART patients is much higher than in the rest of the network. Such clusters may emerge as a result of ART homophily-a tendency for ART patients to preferentially form and maintain relationships with other ART patients. We assessed whether ART clusters may affect the impact of ART on HIV incidence, and how the influence of this effect-modifying variable depends on contextual variables such as HIV prevalence, HIV serosorting, coverage of HIV testing and ART, and adherence to ART.ART homophily can modify the impact of ART on HIV incidence in both directions. In concentrated epidemics and generalized epidemics with moderate HIV prevalence (≈ 10%, ART clusters can enhance the impact of ART on HIV incidence, especially when adherence to ART is poor. In hyperendemic settings (≈ 35% HIV prevalence, ART clusters can reduce the impact of ART on HIV incidence when adherence to ART is high but few people living with HIV (PLWH have been diagnosed. In all contexts, the effects of ART clusters on HIV epidemic dynamics are distinct from those of HIV serosorting.Depending on the programmatic and epidemiological context, ART clusters may enhance or reduce the impact of ART on HIV incidence, in contrast to serosorting, which always leads to a lower impact of ART on HIV incidence. ART homophily and the emergence of ART clusters should be measured empirically and incorporated into more refined models used to plan and evaluate ART programmes.

  19. Beyond Risk Compensation: Clusters of Antiretroviral Treatment (ART) Users in Sexual Networks Can Modify the Impact of ART on HIV Incidence

    Science.gov (United States)

    Delva, Wim; Helleringer, Stéphane

    2016-01-01

    Introduction Concerns about risk compensation—increased risk behaviours in response to a perception of reduced HIV transmission risk—after the initiation of ART have largely been dispelled in empirical studies, but other changes in sexual networking patterns may still modify the effects of ART on HIV incidence. Methods We developed an exploratory mathematical model of HIV transmission that incorporates the possibility of ART clusters, i.e. subsets of the sexual network in which the density of ART patients is much higher than in the rest of the network. Such clusters may emerge as a result of ART homophily—a tendency for ART patients to preferentially form and maintain relationships with other ART patients. We assessed whether ART clusters may affect the impact of ART on HIV incidence, and how the influence of this effect-modifying variable depends on contextual variables such as HIV prevalence, HIV serosorting, coverage of HIV testing and ART, and adherence to ART. Results ART homophily can modify the impact of ART on HIV incidence in both directions. In concentrated epidemics and generalized epidemics with moderate HIV prevalence (≈ 10%), ART clusters can enhance the impact of ART on HIV incidence, especially when adherence to ART is poor. In hyperendemic settings (≈ 35% HIV prevalence), ART clusters can reduce the impact of ART on HIV incidence when adherence to ART is high but few people living with HIV (PLWH) have been diagnosed. In all contexts, the effects of ART clusters on HIV epidemic dynamics are distinct from those of HIV serosorting. Conclusions Depending on the programmatic and epidemiological context, ART clusters may enhance or reduce the impact of ART on HIV incidence, in contrast to serosorting, which always leads to a lower impact of ART on HIV incidence. ART homophily and the emergence of ART clusters should be measured empirically and incorporated into more refined models used to plan and evaluate ART programmes. PMID:27657492

  20. Dynamics of HIV-containing compartments in macrophages reveal sequestration of virions and transient surface connections.

    Directory of Open Access Journals (Sweden)

    Raphaël Gaudin

    Full Text Available During HIV pathogenesis, infected macrophages behave as "viral reservoirs" that accumulate and retain virions within dedicated internal Virus-Containing Compartments (VCCs. The nature of VCCs remains ill characterized and controversial. Using wild-type HIV-1 and a replication-competent HIV-1 carrying GFP internal to the Gag precursor, we analyzed the biogenesis and evolution of VCCs in primary human macrophages. VCCs appear roughly 14 hours after viral protein synthesis is detected, initially contain few motile viral particles, and then mature to fill up with virions that become packed and immobile. The amount of intracellular Gag, the proportion of dense VCCs, and the density of viral particles in their lumen increased with time post-infection. In contrast, the secretion of virions, their infectivity and their transmission to T cells decreased overtime, suggesting that HIV-infected macrophages tend to pack and retain newly formed virions into dense compartments. A minor proportion of VCCs remains connected to the plasma membrane overtime. Surprisingly, live cell imaging combined with correlative light and electron microscopy revealed that such connections can be transient, highlighting their dynamic nature. Together, our results shed light on the late phases of the HIV-1 cycle and reveal some of its macrophage specific features.

  1. Phylodynamics of HIV-1 subtype B among the men-having-sex-with-men (MSM population in Hong Kong.

    Directory of Open Access Journals (Sweden)

    Jonathan Hon-Kwan Chen

    Full Text Available The men-having-sex-with-men (MSM population has become one of the major risk groups for HIV-1 infection in the Asia Pacific countries. Hong Kong is located in the centre of Asia and the transmission history of HIV-1 subtype B transmission among MSM remained unclear. The aim of this study was to investigate the transmission dynamics of HIV-1 subtype B virus in the Hong Kong MSM population. Samples of 125 HIV-1 subtype B infected MSM patients were recruited in this study. Through this study, the subtype B epidemic in the Hong Kong MSM population was identified spreading mainly among local Chinese who caught infection locally. On the other hand, HIV-1 subtype B infected Caucasian MSM caught infection mainly outside Hong Kong. The Bayesian phylogenetic analysis also indicated that 3 separate subtype B epidemics with divergence dates in the 1990s had occurred. The first and latest epidemics were comparatively small-scaled; spreading among the local Chinese MSM while sauna-visiting was found to be the major sex partner sourcing reservoir for the first subtype B epidemic. However, the second epidemic was spread in a large-scale among local Chinese MSM with a number of them having sourced their sex partners through the internet. The epidemic virus was estimated to have a divergence date in 1987 and the infected population in Hong Kong had a logistic growth throughout the past 20 years. Our study elucidated the evolutionary and demographic history of HIV-1 subtype B virus in Hong Kong MSM population. The understanding of transmission and growth model of the subtype B epidemic provides more information on the HIV-1 transmission among MSM population in other Asia Pacific high-income countries.

  2. Epidemics of HIV, HCV and syphilis infection among synthetic drugs only users, heroin-only users and poly-drug users in Southwest China.

    Science.gov (United States)

    Su, Shu; Mao, Limin; Zhao, Jinxian; Chen, Liang; Jing, Jun; Cheng, Feng; Zhang, Lei

    2018-04-26

    The number of poly-drug users who mix use heroin and synthetic drugs (SD) is increasing worldwide. The objective of this study is to measure the risk factors for being infected with hepatitis C (HCV), human immunodeficiency virus (HIV) and syphilis among SD-only users, heroin-only users and poly-drug users. A cross-sectional study was conducted in 2015 from a national HIV surveillance site in Southwest China, 447 poly-drug, 526 SD-only and 318 heroin-only users were recruited. Poly-drug users have higher drug-use frequency, higher rates of drug-sharing and unsafe sexual acts than other users (p users experienced sexual arousal due to drug effects, which is higher than the rate among other drug users. Poly-drug users had the highest prevalence of HIV (10.5%) and syphilis (3.6%), but heroin-only users had the highest prevalence of HCV (66.0%) (all p users, having sex following drug consumption and using drugs ≥1/day were the major risk factors for both HIV (Adjusted odds ratio (AOR) = 2.4, 95% CI [1.8-3.4]; 2.3, [1.6-3.1]) and syphilis infection (AOR = 4.1, [2.1-6.9]; 3.9, [1.8-5.4]). Elevated risk of both HIV and syphilis infection have been established among poly-drug users.

  3. ESTIMATION OF CONSTANT AND TIME-VARYING DYNAMIC PARAMETERS OF HIV INFECTION IN A NONLINEAR DIFFERENTIAL EQUATION MODEL.

    Science.gov (United States)

    Liang, Hua; Miao, Hongyu; Wu, Hulin

    2010-03-01

    Modeling viral dynamics in HIV/AIDS studies has resulted in deep understanding of pathogenesis of HIV infection from which novel antiviral treatment guidance and strategies have been derived. Viral dynamics models based on nonlinear differential equations have been proposed and well developed over the past few decades. However, it is quite challenging to use experimental or clinical data to estimate the unknown parameters (both constant and time-varying parameters) in complex nonlinear differential equation models. Therefore, investigators usually fix some parameter values, from the literature or by experience, to obtain only parameter estimates of interest from clinical or experimental data. However, when such prior information is not available, it is desirable to determine all the parameter estimates from data. In this paper, we intend to combine the newly developed approaches, a multi-stage smoothing-based (MSSB) method and the spline-enhanced nonlinear least squares (SNLS) approach, to estimate all HIV viral dynamic parameters in a nonlinear differential equation model. In particular, to the best of our knowledge, this is the first attempt to propose a comparatively thorough procedure, accounting for both efficiency and accuracy, to rigorously estimate all key kinetic parameters in a nonlinear differential equation model of HIV dynamics from clinical data. These parameters include the proliferation rate and death rate of uninfected HIV-targeted cells, the average number of virions produced by an infected cell, and the infection rate which is related to the antiviral treatment effect and is time-varying. To validate the estimation methods, we verified the identifiability of the HIV viral dynamic model and performed simulation studies. We applied the proposed techniques to estimate the key HIV viral dynamic parameters for two individual AIDS patients treated with antiretroviral therapies. We demonstrate that HIV viral dynamics can be well characterized and

  4. On the dynamics of HIV-AIDS and cryptosporidiosis

    Science.gov (United States)

    Okosun, K. O.; Khan, M. A.; Bonyah, E.; Ogunlade, S. T.

    2017-08-01

    This paper seeks to examine a mathematical model for cryptosporidiosis-HIV co-infection, in order to explore their synergistic relationship in the presence of prevention and treatment. Firstly, we investigate the sub-models and their steady states properties. They are found to be locally and globally stable. Thereafter, the steady states of the co-infected model waswere studied and itthey proved to exhibit backward bifurcation phenomena. Furthermore, we incorporate time-dependent controls in the model and apply Pontryagin's maximum principle, so that we can determine the best optimal strategy to control the co-infected diseases. Finally, we present the numerical results, which show that the best strategy to control co-infection is to combine all the five controls at the same time.

  5. HIV Prevalence and Risk Behaviors in Male to Female (MTF) Transgender Persons in Tijuana, Mexico.

    Science.gov (United States)

    Salas-Espinoza, Kristian Jesús; Menchaca-Diaz, Rufino; Patterson, Thomas L; Urada, Lianne A; Smith, Davey; Strathdee, Steffanie A; Pitpitan, Eileen V

    2017-12-01

    Compared to HIV research on men who have sex with men, less is known about the risks and vulnerabilities for HIV among Male to Female (MTF) transgender persons, particularly in different geographic regions like Mexico. In Tijuana, Mexico, a border city experiencing a dynamic HIV epidemic, no precedent data exists on the MTF transgender population. Our aims were to estimate HIV prevalence and examine the behaviors and characteristics of the population. We conducted a cross-sectional study of 100 MTF transgender persons recruited through time location sampling in 2012. Participants underwent interviewer-administered (paper and pen) surveys and rapid tests for HIV. Descriptive univariate analyses were conducted on various factors, including sociodemographics, substance use, accessing social services (requested vs. received), stigma, and sex behaviors. A total of 22% tested positive for HIV, a prevalence higher than other key populations at risk for HIV in Tijuana.

  6. Reliance on condoms for contraceptive protection among HIV care and treatment clients: a mixed methods study on contraceptive choice and motivation within a generalised epidemic

    Science.gov (United States)

    Church, Kathryn; Wringe, Alison; Fakudze, Phelele; Kikuvi, Joshua; Nhlabatsi, Zelda; Masuku, Rachel; Initiative, Integra; Mayhew, Susannah H

    2014-01-01

    Objectives To (i) describe the contraceptive practices of HIV care and treatment (HCTx) clients in Manzini, Swaziland, including their unmet needs for family planning (FP), and compare these with population-level estimates; and (ii) qualitatively explore the causal factors influencing contraceptive choice and use. Methods Mixed quantitative and qualitative methods were used. A cross-sectional survey conducted among HCTx clients (N=611) investigated FP and condom use patterns. Using descriptive statistics, findings were compared with population-level estimates derived from Swaziland Demographic and Health Survey data, weighted for clustering. In-depth interviews were conducted with HCTx providers (n=16) and clients (n=22) and analysed thematically. Results 64% of HCTx clients reported current contraceptive use; most relied on condoms alone, few practiced dual method use. Rates of condom use for FP among female HCTx clients (77%, 95% CI 71% to 82%) were higher than population-level estimates in the study region (50% HIV-positive, 95% CI 43% to 57%; 37% HIV-negative, 95% CI 31% to 43%); rates of unmet FP needs were similar when condom use consistency was accounted for (32% HCTx, 95% CI 26% to 37%; vs 35% HIV-positive, 95% CI 28% to 43%; 29% HIV-negative, 95% CI 24% to 35%). Qualitative analysis identified motivational factors influencing FP choice: fears of reinfection; a programmatic focus on condoms for people living with HIV; changing sexual behaviours before and after antiretroviral therapy (ART) initiation; failure to disclose to partners; and contraceptive side effect fears. Conclusions Fears of reinfection prevailed over consideration of pregnancy risk. Given current evidence on reinfection, HCTx services must move beyond a narrow focus on condom promotion, particularly for those in seroconcordant relationships, and consider diverse strategies to meet reproductive needs. PMID:24695990

  7. Reliance on condoms for contraceptive protection among HIV care and treatment clients: a mixed methods study on contraceptive choice and motivation within a generalised epidemic.

    Science.gov (United States)

    Church, Kathryn; Wringe, Alison; Fakudze, Phelele; Kikuvi, Joshua; Nhlabatsi, Zelda; Masuku, Rachel; Mayhew, Susannah H

    2014-08-01

    To (i) describe the contraceptive practices of HIV care and treatment (HCTx) clients in Manzini, Swaziland, including their unmet needs for family planning (FP), and compare these with population-level estimates; and (ii) qualitatively explore the causal factors influencing contraceptive choice and use. Mixed quantitative and qualitative methods were used. A cross-sectional survey conducted among HCTx clients (N=611) investigated FP and condom use patterns. Using descriptive statistics, findings were compared with population-level estimates derived from Swaziland Demographic and Health Survey data, weighted for clustering. In-depth interviews were conducted with HCTx providers (n=16) and clients (n=22) and analysed thematically. 64% of HCTx clients reported current contraceptive use; most relied on condoms alone, few practiced dual method use. Rates of condom use for FP among female HCTx clients (77%, 95% CI 71% to 82%) were higher than population-level estimates in the study region (50% HIV-positive, 95% CI 43% to 57%; 37% HIV-negative, 95% CI 31% to 43%); rates of unmet FP needs were similar when condom use consistency was accounted for (32% HCTx, 95% CI 26% to 37%; vs 35% HIV-positive, 95% CI 28% to 43%; 29% HIV-negative, 95% CI 24% to 35%). Qualitative analysis identified motivational factors influencing FP choice: fears of reinfection; a programmatic focus on condoms for people living with HIV; changing sexual behaviours before and after antiretroviral therapy (ART) initiation; failure to disclose to partners; and contraceptive side effect fears. Fears of reinfection prevailed over consideration of pregnancy risk. Given current evidence on reinfection, HCTx services must move beyond a narrow focus on condom promotion, particularly for those in seroconcordant relationships, and consider diverse strategies to meet reproductive needs. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  8. Reducing HIV infection in people who inject drugs is impossible without targeting recently-infected subjects.

    Science.gov (United States)

    Vasylyeva, Tetyana I; Friedman, Samuel R; Lourenco, Jose; Gupta, Sunetra; Hatzakis, Angelos; Pybus, Oliver G; Katzourakis, Aris; Smyrnov, Pavlo; Karamitros, Timokratis; Paraskevis, Dimitrios; Magiorkinis, Gkikas

    2016-11-28

    Although our understanding of viral transmission among people who inject drugs (PWID) has improved, we still know little about when and how many times each injector transmits HIV throughout the duration of infection. We describe HIV dynamics in PWID to evaluate which preventive strategies can be efficient. Due to the notably scarce interventions, HIV-1 spread explosively in Russia and Ukraine in 1990s. By studying this epidemic between 1995 and 2005, we characterized naturally occurring transmission dynamics of HIV among PWID. We combined publicly available HIV pol and env sequences with prevalence estimates from Russia and Ukraine under an evolutionary epidemiology framework to characterize HIV transmissibility between PWID. We then constructed compartmental models to simulate HIV spread among PWID. In the absence of interventions, each injector transmits on average to 10 others. Half of the transmissions take place within 1 month after primary infection, suggesting that the epidemic will expand even after blocking all the post-first month transmissions. Primary prevention can realistically target the first month of infection, and we show that it is very efficient to control the spread of HIV-1 in PWID. Treating acutely infected on top of primary prevention is notably effective. As a large proportion of transmissions among PWID occur within 1 month after infection, reducing and delaying transmissions through scale-up of harm reduction programmes should always form the backbone of HIV control strategies in PWID. Growing PWID populations in the developing world, where primary prevention is scarce, constitutes a public health time bomb.

  9. Recombination of HIV type 1C (C'/C") in Ethiopia: possible link of EthHIV-1C' to subtype C sequences from the high-prevalence epidemics in India and Southern Africa

    NARCIS (Netherlands)

    Pollakis, Georgios; Abebe, Almaz; Kliphuis, Aletta; Rinke de Wit, Tobias F.; Fisseha, Bitew; Tegbaru, Belete; Tesfaye, Girma; Negassa, Hailu; Mengistu, Yohannes; Fontanet, Arnaud L.; Cornelissen, Marion; Goudsmit, Jaap

    2003-01-01

    The magnitude and complexity of the HIV-1 genetic diversity are major challenges for vaccine development. Investigation of the genotypes circulating in areas of high incidence, as well as their interactions, will be a milestone in the development of an efficacious vaccine. Because HIV-1 subtype C

  10. A dynamic case definition is warranted for adequate notification in an extended epidemic setting: the Dutch Q fever outbreak 2007-2009 as exemplar.

    Science.gov (United States)

    Jaramillo-Gutierrez, G; Wegdam-Blans, M C; ter Schegget, R; Korbeeck, J M; van Aken, R; Bijlmer, H A; Tjhie, J H; Koopmans, M P

    2013-10-10

    Q fever is a notifiable disease in the Netherlands:laboratories are obliged to notify possible cases to the Municipal Health Services. These services then try to reconfirm cases with additional clinical and epidemiological data and provide anonymised reports to the national case register of notifiable diseases. Since the start of the 2007–2009 Dutch Q fever outbreak,notification rules remained unchanged, despite new laboratory insights and altered epidemiology. In this study, we retrospectively analysed how these changes influenced the proportion of laboratory-defined acute Q fever cases (confirmed, probable and possible)that were included in the national case register, during(2009) and after the outbreak (2010 and 2011).The number of laboratory-defined cases notified to the Municipal Health Services was 377 in 2009, 96 in 2010 and 50 in 2011. Of these, 186 (49.3%) in 2009, 12(12.5%) in 2010 and 9 (18.0%) in 2011 were confirmed as acute infection by laboratory interpretation. The proportion of laboratory-defined acute Q fever cases that was reconfirmed by the Municipal Health Services and that were included in the national case register decreased from 90% in 2009, to 22% and 24% in 2010 and 2011, respectively. The decrease was observed in all categories of cases, including those considered to be confirmed by laboratory criteria. Continued use ofa pre-outbreak case definition led to over-reporting of cases to the Municipal Health Services in the post-epidemic years. Therefore we recommend dynamic laboratory notification rules, by reviewing case definitions periodically in an ongoing epidemic, as in the Dutch Q fever outbreak.

  11. Dynamics of a Fractional Order HIV Infection Model with Specific Functional Response and Cure Rate

    Directory of Open Access Journals (Sweden)

    Adnane Boukhouima

    2017-01-01

    Full Text Available We propose a fractional order model in this paper to describe the dynamics of human immunodeficiency virus (HIV infection. In the model, the infection transmission process is modeled by a specific functional response. First, we show that the model is mathematically and biologically well posed. Second, the local and global stabilities of the equilibria are investigated. Finally, some numerical simulations are presented in order to illustrate our theoretical results.

  12. The dynamics of injection drug users' personal networks and HIV risk behaviors.

    Science.gov (United States)

    Costenbader, Elizabeth C; Astone, Nan M; Latkin, Carl A

    2006-07-01

    While studies of the social networks of injection drug users (IDUs) have provided insight into how the structures of interpersonal relationships among IDUs affect HIV risk behaviors, the majority of these studies have been cross-sectional. The present study examined the dynamics of IDUs' social networks and HIV risk behaviors over time. Using data from a longitudinal HIV-intervention study conducted in Baltimore, MD, this study assessed changes in the composition of the personal networks of 409 IDUs. We used a multi-nomial logistic regression analysis to assess the association between changes in network composition and simultaneous changes in levels of injection HIV risk behaviors. Using the regression parameters generated by the multi-nomial model, we estimated the predicted probability of being in each of four HIV risk behavior change groups. Compared to the base case, individuals who reported an entirely new set of drug-using network contacts at follow-up were more than three times as likely to be in the increasing risk group. In contrast, reporting all new non-drug-using contacts at follow-up increased the likelihood of being in the stable low-risk group by almost 50% and decreased the probability of being in the consistently high-risk group by more than 70%. The findings from this study show that, over and above IDUs' baseline characteristics, changes in their personal networks are associated with changes in individuals' risky injection behaviors. They also suggest that interventions aimed at reducing HIV risk among IDUs might benefit from increasing IDUs' social contacts with individuals who are not drug users.

  13. The HIV, syphilis, and HCV epidemics among female sex workers in china: results from a serial cross-sectional study between 2008 and 2012.

    Science.gov (United States)

    Wang, Lu; Tang, Weiming; Wang, Lan; Qian, Shasha; Li, Yin-Ge; Xing, Jiannan; Li, Dongmin; Ding, Zhengwei; Babu, Giridhara R; Wang, Ning

    2014-07-01

    Studies on the transmission of human immunodeficiency virus (HIV) and sexually transmitted diseases in female sex workers (FSWs) have been limited primarily to inferences drawn by focusing on defined geographical areas. This serial cross-sectional study was conducted in mainland China from 2008 through 2012. Data for 827 079 participants was analyzed. We classified venues such as karaoke bars and hotels as high tier and venues such as hair salons and barbershops, massage parlors, and other public outdoor venues as low tier based on the participants' socioeconomic status. FSWs who worked at the venues and those who were present on the days of the survey were recruited. The prevalence of HIV decreased from 0.6% in 2008 to 0.3% in 2012, the syphilis prevalence ranged from 2.4% to 3.2% between 2008 and 2012, and hepatitis C virus (HCV) prevalence decreased from 0.9% in 2008 to 0.8% in 2012. Further, we found that HIV, syphilis, and HCV prevalence proportions were high in FSWs from low tiers. HIV, syphilis, and HCV prevalence among FSWs in our study decreased during the study period. Comprehensive intervention strategies, particularly those that focus on low-tier and older FSWs, are needed in order to decrease the disease burden in this population. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  14. Trends in overall opportunistic illnesses, Pneumocystis carinii pneumonia, cerebral toxoplasmosis and Mycobacterium avium complex incidence rates over the 30 years of the HIV epidemic: a systematic review

    Directory of Open Access Journals (Sweden)

    Lara Coelho

    2014-03-01

    Conclusions: Opportunistic illnesses remain an important public health problem. To better guide health policies in low/middle-income settings, multicenter cohort studies should be encouraged. Studies from Brazil are urgently needed to assess the current burden of opportunistic illnesses in our population and to support the planning of HIV/AIDS health care services organization.

  15. Concurrent sexual partnerships and associated factors: a cross-sectional population-based survey in a rural community in Africa with a generalised HIV epidemic

    Directory of Open Access Journals (Sweden)

    Karabarinde Alex

    2011-08-01

    Full Text Available Abstract Background Although concurrent sexual partnerships may play an important role in HIV transmission in Africa, the lack of an agreed definition of concurrency and of standard methodological approaches has hindered studies. In a long-standing general population cohort in rural Uganda we assessed the prevalence of concurrency and investigated its association with sociodemographic and behavioural factors and with HIV prevalence, using the new recommended standard definition and methodological approaches. Methods As part of the 2010 annual cohort HIV serosurvey among adults, we used a structured questionnaire to collect information on sociodemographic and behavioural factors and to measure standard indicators of concurrency using the recommended method of obtaining sexual-partner histories. We used logistic regression to build a multivariable model of factors independently associated with concurrency. Results Among those eligible, 3,291 (66% males and 4,052 (72% females participated in the survey. Among currently married participants, 11% of men and 25% of women reported being in a polygynous union. Among those with a sexual partner in the past year, the proportion reporting at least one concurrent partnership was 17% in males and 0.5% in females. Polygyny accounted for a third of concurrency in men and was not associated with increased HIV risk. Among men there was no evidence of an association between concurrency and HIV prevalence (but too few women reported concurrency to assess this after adjusting for confounding. Regarding sociodemographic factors associated with concurrency, females were significantly more likely to be younger, unmarried, and of lower socioeconomic status than males. Behavioural factors associated with concurrency were young age at first sex, increasing lifetime partners, and a casual partner in the past year (among men and women and problem drinking (only men. Conclusions Our findings based on the new standard

  16. A stochastic spatial model of HIV dynamics with an asymmetric battle between the virus and the immune system

    International Nuclear Information System (INIS)

    Lin Hai; Shuai, J W

    2010-01-01

    A stochastic spatial model based on the Monte Carlo approach is developed to study the dynamics of human immunodeficiency virus (HIV) infection. We aim to propose a more detailed and realistic simulation frame by incorporating many important features of HIV dynamics, which include infections, replications and mutations of viruses, antigen recognitions, activations and proliferations of lymphocytes, and diffusions, encounters and interactions of virions and lymphocytes. Our model successfully reproduces the three-phase pattern observed in HIV infection, and the simulation results for the time distribution from infection to AIDS onset are also in good agreement with the clinical data. The interactions of viruses and the immune system in all the three phases are investigated. We assess the relative importance of various immune system components in the acute phase. The dynamics of how the two important factors, namely the viral diversity and the asymmetric battle between HIV and the immune system, result in AIDS are investigated in detail with the model.

  17. Traditional healers, HIV/AIDS and company programmes in South ...

    African Journals Online (AJOL)

    Traditional healers' diverse and fluid beliefs about HIV and AIDS are ... healing practices could be promoted in workplace responses to HIV/AIDS. ... as help coordinate a wider and more effective response to the HIV epidemic in South Africa.

  18. Networked SIS Epidemics With Awareness

    KAUST Repository

    Paarporn, Keith

    2017-07-20

    We study a susceptible-infected-susceptible epidemic process over a static contact network where the nodes have partial information about the epidemic state. They react by limiting their interactions with their neighbors when they believe the epidemic is currently prevalent. A node\\'s awareness is weighted by the fraction of infected neighbors in their social network, and a global broadcast of the fraction of infected nodes in the entire network. The dynamics of the benchmark (no awareness) and awareness models are described by discrete-time Markov chains, from which mean-field approximations (MFAs) are derived. The states of the MFA are interpreted as the nodes\\' probabilities of being infected. We show a sufficient condition for the existence of a

  19. HIV-1 subtype A gag variability and epitope evolution.

    Science.gov (United States)

    Abidi, Syed Hani; Kalish, Marcia L; Abbas, Farhat; Rowland-Jones, Sarah; Ali, Syed

    2014-01-01

    The aim of this study was to examine the course of time-dependent evolution of HIV-1 subtype A on a global level, especially with respect to the dynamics of immunogenic HIV gag epitopes. We used a total of 1,893 HIV-1 subtype A gag sequences representing a timeline from 1985 through 2010, and 19 different countries in Africa, Europe and Asia. The phylogenetic relationship of subtype A gag and its epidemic dynamics was analysed through a Maximum Likelihood tree and Bayesian Skyline plot, genomic variability was measured in terms of G → A substitutions and Shannon entropy, and the time-dependent evolution of HIV subtype A gag epitopes was examined. Finally, to confirm observations on globally reported HIV subtype A sequences, we analysed the gag epitope data from our Kenyan, Pakistani, and Afghan cohorts, where both cohort-specific gene epitope variability and HLA restriction profiles of gag epitopes were examined. The most recent common ancestor of the HIV subtype A epidemic was estimated to be 1956 ± 1. A period of exponential growth began about 1980 and lasted for approximately 7 years, stabilized for 15 years, declined for 2-3 years, then stabilized again from about 2004. During the course of evolution, a gradual increase in genomic variability was observed that peaked in 2005-2010. We observed that the number of point mutations and novel epitopes in gag also peaked concurrently during 2005-2010. It appears that as the HIV subtype A epidemic spread globally, changing population immunogenetic pressures may have played a role in steering immune-evolution of this subtype in new directions. This trend is apparent in the genomic variability and epitope diversity of HIV-1 subtype A gag sequences.

  20. HIV-1 subtype A gag variability and epitope evolution.

    Directory of Open Access Journals (Sweden)

    Syed Hani Abidi

    Full Text Available OBJECTIVE: The aim of this study was to examine the course of time-dependent evolution of HIV-1 subtype A on a global level, especially with respect to the dynamics of immunogenic HIV gag epitopes. METHODS: We used a total of 1,893 HIV-1 subtype A gag sequences representing a timeline from 1985 through 2010, and 19 different countries in Africa, Europe and Asia. The phylogenetic relationship of subtype A gag and its epidemic dynamics was analysed through a Maximum Likelihood tree and Bayesian Skyline plot, genomic variability was measured in terms of G → A substitutions and Shannon entropy, and the time-dependent evolution of HIV subtype A gag epitopes was examined. Finally, to confirm observations on globally reported HIV subtype A sequences, we analysed the gag epitope data from our Kenyan, Pakistani, and Afghan cohorts, where both cohort-specific gene epitope variability and HLA restriction profiles of gag epitopes were examined. RESULTS: The most recent common ancestor of the HIV subtype A epidemic was estimated to be 1956 ± 1. A period of exponential growth began about 1980 and lasted for approximately 7 years, stabilized for 15 years, declined for 2-3 years, then stabilized again from about 2004. During the course of evolution, a gradual increase in genomic variability was observed that peaked in 2005-2010. We observed that the number of point mutations and novel epitopes in gag also peaked concurrently during 2005-2010. CONCLUSION: It appears that as the HIV subtype A epidemic spread globally, changing population immunogenetic pressures may have played a role in steering immune-evolution of this subtype in new directions. This trend is apparent in the genomic variability and epitope diversity of HIV-1 subtype A gag sequences.

  1. Epidemic processes in complex networks

    Science.gov (United States)

    Pastor-Satorras, Romualdo; Castellano, Claudio; Van Mieghem, Piet; Vespignani, Alessandro

    2015-07-01

    In recent years the research community has accumulated overwhelming evidence for the emergence of complex and heterogeneous connectivity patterns in a wide range of biological and sociotechnical systems. The complex properties of real-world networks have a profound impact on the behavior of equilibrium and nonequilibrium phenomena occurring in various systems, and the study of epidemic spreading is central to our understanding of the unfolding of dynamical processes in complex networks. The theoretical analysis of epidemic spreading in heterogeneous networks requires the development of novel analytical frameworks, and it has produced results of conceptual and practical relevance. A coherent and comprehensive review of the vast research activity concerning epidemic processes is presented, detailing the successful theoretical approaches as well as making their limits and assumptions clear. Physicists, mathematicians, epidemiologists, computer, and social scientists share a common interest in studying epidemic spreading and rely on similar models for the description of the diffusion of pathogens, knowledge, and innovation. For this reason, while focusing on the main results and the paradigmatic models in infectious disease modeling, the major results concerning generalized social contagion processes are also presented. Finally, the research activity at the forefront in the study of epidemic spreading in coevolving, coupled, and time-varying networks is reported.

  2. Toward a generalized theory of epidemic awareness in social networks

    Science.gov (United States)

    Wu, Qingchu; Zhu, Wenfang

    We discuss the dynamics of a susceptible-infected-susceptible (SIS) model with local awareness in networks. Individual awareness to the infectious disease is characterized by a general function of epidemic information in its neighborhood. We build a high-accuracy approximate equation governing the spreading dynamics and derive an approximate epidemic threshold above which the epidemic spreads over the whole network. Our results extend the previous work and show that the epidemic threshold is dependent on the awareness function in terms of one infectious neighbor. Interestingly, when a pow-law awareness function is chosen, the epidemic threshold can emerge in infinite networks.

  3. Modeling viral coevolution: HIV multi-clonal persistence and competition dynamics

    Science.gov (United States)

    Bagnoli, F.; Liò, P.; Sguanci, L.

    2006-07-01

    The coexistence of different viral strains (quasispecies) within the same host are nowadays observed for a growing number of viruses, most notably HIV, Marburg and Ebola, but the conditions for the formation and survival of new strains have not yet been understood. We present a model of HIV quasispecies competition, which describes the conditions of viral quasispecies coexistence under different immune system conditions. Our model incorporates both T and B cells responses, and we show that the role of B cells is important and additive to that of T cells. Simulations of coinfection (simultaneous infection) and superinfection (delayed secondary infection) scenarios in the early stages (days) and in the late stages of the infection (years) are in agreement with emerging molecular biology findings. The immune response induces a competition among similar phenotypes, leading to differentiation (quasispeciation), escape dynamics and complex oscillations of viral strain abundance. We found that the quasispecies dynamics after superinfection or coinfection has time scales of several months and becomes even slower when the immune system response is weak. Our model represents a general framework to study the speed and distribution of HIV quasispecies during disease progression, vaccination and therapy.

  4. Global Dynamics of HIV Infection of CD4+ T Cells and Macrophages

    Directory of Open Access Journals (Sweden)

    A. M. Elaiw

    2013-01-01

    Full Text Available We study the global dynamics of an HIV infection model describing the interaction of the HIV with CD4+ T cells and macrophages. The incidence rate of virus infection and the growth rate of the uninfected CD4+ T cells and macrophages are given by general functions. We have incorporated two types of distributed delays into the model to account for the time delay between the time the uninfected cells are contacted by the virus particle and the time for the emission of infectious (matures virus particles. We have established a set of conditions which are sufficient for the global stability of the steady states of the model. Using Lyapunov functionals and LaSalle's invariant principle, we have proven that if the basic reproduction number R0 is less than or equal to unity, then the uninfected steady state is globally asymptotically stable (GAS, and if the infected steady state exists, then it is GAS.

  5. Prevalence of HIV at the Kokoyo informal gold mining site: what lies behind the glitter of gold with regard to HIV epidemics in Mali? A community-based approach (the ANRS-12339 Sanu Gundo cross-sectional survey).

    Science.gov (United States)

    Sagaon-Teyssier, Luis; Balique, Hubert; Diallo, Fodié; Kalampalikis, Nikos; Mora, Marion; Bourrelly, Michel; Suzan-Monti, Marie; Spire, Bruno; Dembélé Keita, Bintou

    2017-08-03

    The aim of this article was to estimate HIV prevalence and the factors associated with HIV seropositivity in the population living and working at the informal artisanal small-scale gold mining (IASGM) site of Kokoyo in Mali, using data from the Sanu Gundo survey. Our main hypothesis was that HIV prevalence is higher in the context of IASGM than in the country as a whole. The ANRS-12339 Sanu Gundo was a cross-sectional survey conducted in December 2015. The quantitative survey consisted of face-to-face administration of questionnaires. Five focus groups were conducted for the qualitative survey. HIV prevalence was calculated for the sample, and according to the type of activity performed in IASGM. The IASGM site of Kokoyo, one of the largest sites in Mali (between 6000 and 1000 people). 224 respondents: 37.5% were gold-diggers, 33% retail traders, 6.7% tombolomas (ie, traditional guards) and 9% female sex workers. The remaining 13.8% reported another activity (mainly street vending). HIV prevalence and HIV prevalence according to subgroup, as defined by their activity at the Kokoyo IASGM. A probit logistic regression was implemented to estimate the characteristics associated with HIV seropositivity. HIV prevalence for the total sample was 8% (95% CI 7.7% to 8.3%), which is much higher than the 2015 national prevalence of 1.3%Joint United Nations Programme on HIV/AIDS (UNAIDS). The probability of HIV seropositivity was 7.8% (p=0.037) higher for female non-sex workers than for any other category, and this probability increased significantly with age. Qualitative data revealed the non-systematic use of condoms with sex workers; and long distance from health services was the main barrier to accessing care. Integrated policymaking should pay special attention to infectious diseases among populations in IASGM zones. Bringing information/prevention activities closer to people working in gold mining zones is an urgent public health action. © Article author(s) (or their

  6. Molecular epidemiology of HIV-1 in Iceland: Early introductions, transmission dynamics and recent outbreaks among injection drug users.

    Science.gov (United States)

    Sallam, Malik; Esbjörnsson, Joakim; Baldvinsdóttir, Guðrún; Indriðason, Hlynur; Björnsdóttir, Thora Björg; Widell, Anders; Gottfreðsson, Magnús; Löve, Arthur; Medstrand, Patrik

    2017-04-01

    The molecular epidemiology of HIV-1 in Iceland has not been described so far. Detailed analyses of the dynamics of HIV-1 can give insights for prevention of virus spread. The objective of the current study was to characterize the genetic diversity and transmission dynamics of HIV-1 in Iceland. Partial HIV-1 pol (1020bp) sequences were generated from 230 Icelandic samples, representing 77% of all HIV-1 infected individuals reported in the country 1985-2012. Maximum likelihood phylogenies were reconstructed for subtype/CRF assignment and determination of transmission clusters. Timing and demographic growth patterns were determined in BEAST. HIV-1 infection in Iceland was dominated by subtype B (63%, n=145) followed by subtype C (10%, n=23), CRF01_AE (10%, n=22), sub-subtype A1 (7%, n=15) and CRF02_AG (7%, n=15). Trend analysis showed an increase in non-B subtypes/CRFs in Iceland over the study period (p=0.003). The highest proportion of phylogenetic clustering was found among injection drug users (IDUs; 89%), followed by heterosexuals (70%) and men who have sex with men (35%). The time to the most recent common ancestor of the oldest subtype B cluster dated back to 1978 (median estimate, 95% highest posterior density interval: 1974-1981) suggesting an early introduction of HIV-1 into Iceland. A previously reported increase in HIV-1 incidence among IDUs 2009-2011 was revealed to be due to two separate outbreaks. Our study showed that a variety of HIV-1 subtypes and CRFs were prevalent in Iceland 1985-2012, with subtype B being the dominant form both in terms of prevalence and domestic spread. The rapid increase of HIV-1 infections among IDUs following a major economic crisis in Iceland raises questions about casual associations between economic factors, drug use and public health. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Progress in Reversing the HIV Epidemic through Intensified Access to Antiretroviral Therapy: Results from a Nationally Representative Population-Based Survey in Kenya, 2012

    Science.gov (United States)

    Kim, Andrea A.; Mukui, Irene; N’gan’ga, Lucy; Katana, Abraham; Koros, Dan; Wamicwe, Joyce; De Cock, Kevin M.

    2016-01-01

    Background In 2014, the Joint United Nations Programme on HIV/AIDS (UNAIDS) called for 90% of persons living with HIV (PLHIV) to know their status, 90% of these to be on antiretroviral therapy (ART), and 90% of these to be virally suppressed by 2020 (90-90-90). It is not clear whether planned ART scale-up in countries whose eligibility criteria for ART initiation are based on recommendations from the 2013 World Health Organization treatment guidelines will be sufficient to meet UNAIDS' new global targets. Materials and Methods Using data from a nationally representative population-based household survey of persons in Kenya we compared coverage and unmet need associated with HIV diagnosis, ART, and viral suppression among PLHIV aged 15–64 years in 2012 based on criteria outlined in the 2014 national ART guidelines and UNAIDS’ 90-90-90 goals. Estimates were weighted to account for sampling probability and nonresponse. Results Eight in ten PLHIV aged 15–64 years needed ART based on treatment eligibility. Need for treatment based on the national treatment policy was 97.4% of treatment need based on UNAIDS’ 90-90-90 goals, requiring an excess of 24,000 PLHIV to access treatment beyond those eligible for ART to achieve UNAIDS’ 90-90-90 treatment target. The gap in treatment coverage was high, ranging from 43.1% nationally to 52.3% in Nyanza among treatment-eligible PLHIV and 44.6% nationally to 52.4% in Nyanza among all PLHIV. Conclusion Maintaining the current pace of ART scale-up in Kenya will result in thousands of PLHIV unreached, many with high viral load and at-risk of transmitting infection to others. Careful strategies for reaching 90-90-90 will be instrumental in determining whether intensified access to treatment can be achieved to reach all who require ART. PMID:26930291

  8. Rethinking the Poverty-disease Nexus: the Case of HIV/AIDS in South Africa.

    Science.gov (United States)

    Pienaar, Kiran

    2017-09-01

    While it is well-established that poverty and disease are intimately connected, the nature of this connection and the role of poverty in disease causation remains contested in scientific and social studies of disease. Using the case of HIV/AIDS in South Africa and drawing on a theoretically grounded analysis, this paper reconceptualises disease and poverty as ontologically entangled. In the context of the South African HIV epidemic, this rethinking of the poverty-disease dynamic enables an account of how social forces such as poverty become embodied in the very substance of disease to produce ontologies of HIV/AIDS unique to South Africa.

  9. Comparative Analysis of Gender Differences in the HIV-1 Infection Dynamics

    Science.gov (United States)

    Ballesteros, P.; Estrada, J. L.; Barriga, G.; Molinar, F.; Hernández, M. C.; Huerta, L.; Cocho, G.; Villarreal, C.

    2006-09-01

    We have performed a retrospective study of the HIV-1 viral load and CD4 T-cell counts in blood plasma of more than 3000 Mexican patients. We found that women had consistently lower viral loads than men for CD4 T-cell counts higher than 50 cells/μL and higher viral loads when CD4 T-cell counts were at most 50 cells/μL. Our results show the same pattern as the one reported in studies performed in European and North American populations. We present theoretical predictions of viral load dynamics during highly active antiretroviral therapy taking into account gender differences.

  10. Addressing gender dynamics and engaging men in HIV programs: lessons learned from Horizons research.

    Science.gov (United States)

    Pulerwitz, Julie; Michaelis, Annie; Verma, Ravi; Weiss, Ellen

    2010-01-01

    In the field of human immunodeficiency virus (HIV) prevention, there has been increasing interest in the role that gender plays in HIV and violence risk, and in successfully engaging men in the response. This article highlights findings from more than 10 studies in Asia, Africa, and Latin America--conducted from 1997 through 2007 as part of the Horizons program--that have contributed to understanding the relationship between gender and men's behaviors, developing useful measurement tools for gender norms, and designing and evaluating the impact of gender-focused program strategies. Studies showed significant associations between support for inequitable norms and risk, such as more partner violence and less condom use. Programmatic lessons learned ranged from insights into appropriate media messages, to strategies to engage men in critically reflecting upon gender inequality, to the qualities of successful program facilitators. The portfolio of work reveals the potential and importance of directly addressing gender dynamics in HIV- and violence-prevention programs for both men and women.

  11. Application of optimal control strategies to HIV-malaria co-infection dynamics

    Science.gov (United States)

    Fatmawati; Windarto; Hanif, Lathifah

    2018-03-01

    This paper presents a mathematical model of HIV and malaria co-infection transmission dynamics. Optimal control strategies such as malaria preventive, anti-malaria and antiretroviral (ARV) treatments are considered into the model to reduce the co-infection. First, we studied the existence and stability of equilibria of the presented model without control variables. The model has four equilibria, namely the disease-free equilibrium, the HIV endemic equilibrium, the malaria endemic equilibrium, and the co-infection equilibrium. We also obtain two basic reproduction ratios corresponding to the diseases. It was found that the disease-free equilibrium is locally asymptotically stable whenever their respective basic reproduction numbers are less than one. We also conducted a sensitivity analysis to determine the dominant factor controlling the transmission. sic reproduction numbers are less than one. We also conducted a sensitivity analysis to determine the dominant factor controlling the transmission. Then, the optimal control theory for the model was derived analytically by using Pontryagin Maximum Principle. Numerical simulations of the optimal control strategies are also performed to illustrate the results. From the numerical results, we conclude that the best strategy is to combine the malaria prevention and ARV treatments in order to reduce malaria and HIV co-infection populations.

  12. Rare HIV-1 Subtype J Genomes and a New H/U/CRF02_AG Recombinant Genome Suggests an Ancient Origin of HIV-1 in Angola.

    Science.gov (United States)

    Bártolo, Inês; Calado, Rita; Borrego, Pedro; Leitner, Thomas; Taveira, Nuno

    2016-08-01

    Angola has an extremely diverse HIV-1 epidemic fueled in part by the frequent interchange of people with the Democratic Republic of Congo (DRC) and Republic of Congo (RC). Characterization of HIV-1 strains circulating in Angola should help to better understand the origin of HIV-1 subtypes and recombinant forms and their transmission dynamics. In this study we characterize the first near full-length HIV-1 genomic sequences from HIV-1 infected individuals from Angola. Samples were obtained in 1993 from three HIV-1 infected patients living in Cabinda, Angola. Near full-length genomic sequences were obtained from virus isolates. Maximum likelihood phylogenetic tree inference and analyses of potential recombination patterns were performed to evaluate the sequence classifications and origins. Phylogenetic and recombination analyses revealed that one virus was a pure subtype J, another mostly subtype J with a small uncertain region, and the final virus was classified as a H/U/CRF02_AG recombinant. Consistent with their epidemiological data, the subtype J sequences were more closely related to each other than to other J sequences previously published. Based on the env gene, taxa from Angola occur throughout the global subtype J phylogeny. HIV-1 subtypes J and H are present in Angola at low levels since at least 1993. Low transmission efficiency and/or high recombination potential may explain their limited epidemic success in Angola and worldwide. The high diversity of rare subtypes in Angola suggests that Angola was part of the early establishment of the HIV-1 pandemic.

  13. Epidemic processes in complex networks

    OpenAIRE

    Pastor Satorras, Romualdo; Castellano, Claudio; Van Mieghem, Piet; Vespignani, Alessandro

    2015-01-01

    In recent years the research community has accumulated overwhelming evidence for the emergence of complex and heterogeneous connectivity patterns in a wide range of biological and sociotechnical systems. The complex properties of real-world networks have a profound impact on the behavior of equilibrium and nonequilibrium phenomena occurring in various systems, and the study of epidemic spreading is central to our understanding of the unfolding of dynamical processes in complex networks. The t...

  14. Methodological challenges in collecting social and behavioural data regarding the HIV epidemic among gay and other men who have sex with men in Australia.

    Directory of Open Access Journals (Sweden)

    Iryna B Zablotska

    Full Text Available BACKGROUND: Behavioural surveillance and research among gay and other men who have sex with men (GMSM commonly relies on non-random recruitment approaches. Methodological challenges limit their ability to accurately represent the population of adult GMSM. We compared the social and behavioural profiles of GMSM recruited via venue-based, online, and respondent-driven sampling (RDS and discussed their utility for behavioural surveillance. METHODS: Data from four studies were selected to reflect each recruitment method. We compared demographic characteristics and the prevalence of key indicators including sexual and HIV testing practices obtained from samples recruited through different methods, and population estimates from respondent-driven sampling partition analysis. RESULTS: Overall, the socio-demographic profile of GMSM was similar across samples, with some differences observed in age and sexual identification. Men recruited through time-location sampling appeared more connected to the gay community, reported a greater number of sexual partners, but engaged in less unprotected anal intercourse with regular (UAIR or casual partners (UAIC. The RDS sample overestimated the proportion of HIV-positive men and appeared to recruit men with an overall higher number of sexual partners. A single-website survey recruited a sample with characteristics which differed considerably from the population estimates with regards to age, ethnically diversity and behaviour. Data acquired through time-location sampling underestimated the rates of UAIR and UAIC, while RDS and online sampling both generated samples that underestimated UAIR. Simulated composite samples combining recruits from time-location and multi-website online sampling may produce characteristics more consistent with the population estimates, particularly with regards to sexual practices. CONCLUSION: Respondent-driven sampling produced the sample that was most consistent to population estimates

  15. Methodological challenges in collecting social and behavioural data regarding the HIV epidemic among gay and other men who have sex with men in Australia.

    Science.gov (United States)

    Zablotska, Iryna B; Frankland, Andrew; Holt, Martin; de Wit, John; Brown, Graham; Maycock, Bruce; Fairley, Christopher; Prestage, Garrett

    2014-01-01

    Behavioural surveillance and research among gay and other men who have sex with men (GMSM) commonly relies on non-random recruitment approaches. Methodological challenges limit their ability to accurately represent the population of adult GMSM. We compared the social and behavioural profiles of GMSM recruited via venue-based, online, and respondent-driven sampling (RDS) and discussed their utility for behavioural surveillance. Data from four studies were selected to reflect each recruitment method. We compared demographic characteristics and the prevalence of key indicators including sexual and HIV testing practices obtained from samples recruited through different methods, and population estimates from respondent-driven sampling partition analysis. Overall, the socio-demographic profile of GMSM was similar across samples, with some differences observed in age and sexual identification. Men recruited through time-location sampling appeared more connected to the gay community, reported a greater number of sexual partners, but engaged in less unprotected anal intercourse with regular (UAIR) or casual partners (UAIC). The RDS sample overestimated the proportion of HIV-positive men and appeared to recruit men with an overall higher number of sexual partners. A single-website survey recruited a sample with characteristics which differed considerably from the population estimates with regards to age, ethnically diversity and behaviour. Data acquired through time-location sampling underestimated the rates of UAIR and UAIC, while RDS and online sampling both generated samples that underestimated UAIR. Simulated composite samples combining recruits from time-location and multi-website online sampling may produce characteristics more consistent with the population estimates, particularly with regards to sexual practices. Respondent-driven sampling produced the sample that was most consistent to population estimates, but this methodology is complex and logistically demanding

  16. Percolation and epidemics in random clustered networks

    Science.gov (United States)

    Miller, Joel C.

    2009-08-01

    The social networks that infectious diseases spread along are typically clustered. Because of the close relation between percolation and epidemic spread, the behavior of percolation in such networks gives insight into infectious disease dynamics. A number of authors have studied percolation or epidemics in clustered networks, but the networks often contain preferential contacts in high degree nodes. We introduce a class of random clustered networks and a class of random unclustered networks with the same preferential mixing. Percolation in the clustered networks reduces the component sizes and increases the epidemic threshold compared to the unclustered networks.

  17. Modeling Epidemics Spreading on Social Contact Networks.

    Science.gov (United States)

    Zhang, Zhaoyang; Wang, Honggang; Wang, Chonggang; Fang, Hua

    2015-09-01

    Social contact networks and the way people interact with each other are the key factors that impact on epidemics spreading. However, it is challenging to model the behavior of epidemics based on social contact networks due to their high dynamics. Traditional models such as susceptible-infected-recovered (SIR) model ignore the crowding or protection effect and thus has some unrealistic assumption. In this paper, we consider the crowding or protection effect and develop a novel model called improved SIR model. Then, we use both deterministic and stochastic models to characterize the dynamics of epidemics on social contact networks. The results from both simulations and real data set conclude that the epidemics are more likely to outbreak on social contact networks with higher average degree. We also present some potential immunization strategies, such as random set immunization, dominating set immunization, and high degree set immunization to further prove the conclusion.

  18. Outpatient HIV care in the Netherlands

    NARCIS (Netherlands)

    Engelhard, E.A.N.

    2017-01-01

    HIV is now, as a result of cART, a treatable condition. Sadly, as reflected by the large number of annual HIV-related deaths and new infections, managing HIV infection and curbing the epidemic has proven extremely challenging. To achieve world without HIV and AIDS, we need to ensure that all

  19. Dynamic of CSF and serum biomarkers in HIV-1 subtype C encephalitis with CNS genetic compartmentalization-case study.

    Science.gov (United States)

    de Almeida, Sergio M; Rotta, Indianara; Ribeiro, Clea E; Oliveira, Michelli F; Chaillon, Antoine; de Pereira, Ana Paula; Cunha, Ana Paula; Zonta, Marise; Bents, Joao França; Raboni, Sonia M; Smith, Davey; Letendre, Scott; Ellis, Ronald J

    2017-06-01

    Despite the effective suppression of viremia with antiretroviral therapy, HIV can still replicate in the central nervous system (CNS). This was a longitudinal study of the cerebrospinal fluid (CSF) and serum dynamics of several biomarkers related to inflammation, the blood-brain barrier, neuronal injury, and IgG intrathecal synthesis in serial samples of CSF and serum from a patient infected with HIV-1 subtype C with CNS compartmentalization.The phylogenetic analyses of plasma and CSF samples in an acute phase using next-generation sequencing and F-statistics analysis of C2-V3 haplotypes revealed distinct compartmentalized CSF viruses in paired CSF and peripheral blood mononuclear cell samples. The CSF biomarker analysis in this patient showed that symptomatic CSF escape is accompanied by CNS inflammation, high levels of cell and humoral immune biomarkers, CNS barrier dysfunction, and an increase in neuronal injury biomarkers with demyelization. Independent and isolated HIV replication can occur in the CNS, even in HIV-1 subtype C, leading to compartmentalization and development of quasispecies distinct from the peripheral plasma. These immunological aspects of the HIV CNS escape have not been described previously. To our knowledge, this is the first report of CNS HIV escape and compartmentalization in HIV-1 subtype C.

  20. 'The epidemic in this country has the face of a woman' 1 : Gender ...

    African Journals Online (AJOL)

    'The epidemic in this country has the face of a woman' 1 : Gender and HIV/AIDS in South Africa 2. ... Abstract. Epidemiological data clearly show that the highest levels of HIV prevalence occur in sub-Saharan Africa. ... Keywords: gender inequality, HIV prevention, socio-cultural and material aspects, women. African Journal ...

  1. HIV Model Parameter Estimates from Interruption Trial Data including Drug Efficacy and Reservoir Dynamics

    Science.gov (United States)

    Luo, Rutao; Piovoso, Michael J.; Martinez-Picado, Javier; Zurakowski, Ryan

    2012-01-01

    Mathematical models based on ordinary differential equations (ODE) have had significant impact on understanding HIV disease dynamics and optimizing patient treatment. A model that characterizes the essential disease dynamics can be used for prediction only if the model parameters are identifiable from clinical data. Most previous parameter identification studies for HIV have used sparsely sampled data from the decay phase following the introduction of therapy. In this paper, model parameters are identified from frequently sampled viral-load data taken from ten patients enrolled in the previously published AutoVac HAART interruption study, providing between 69 and 114 viral load measurements from 3–5 phases of viral decay and rebound for each patient. This dataset is considerably larger than those used in previously published parameter estimation studies. Furthermore, the measurements come from two separate experimental conditions, which allows for the direct estimation of drug efficacy and reservoir contribution rates, two parameters that cannot be identified from decay-phase data alone. A Markov-Chain Monte-Carlo method is used to estimate the model parameter values, with initial estimates obtained using nonlinear least-squares methods. The posterior distributions of the parameter estimates are reported and compared for all patients. PMID:22815727

  2. Spatial Epidemiology of HIV among Injection Drug Users in Tijuana, Mexico.

    Science.gov (United States)

    Brouwer, Kimberly C; Rusch, Melanie L; Weeks, John R; Lozada, Remedios; Vera, Alicia; Magis-Rodríguez, Carlos; Strathdee, Steffanie A

    2012-01-01

    The northwest border city of Tijuana is Mexico's fifth largest and is experiencing burgeoning drug use and human immunodeficiency virus (HIV) epidemics. Since local geography influences disease risk, we explored the spatial distribution of HIV among injection drug users (IDUs). From 2006-2007, 1056 IDUs were recruited using respondent-driven sampling, and then followed for eighteen months. Participants underwent semi-annual surveys, mapping, and testing for HIV, tuberculosis, and syphilis. Using Average Nearest Neighbor and Getis-Ord Gi* statistics, locations where participants lived, worked, bought and injected drugs were compared with HIV status and environmental and behavioral factors. Median age was thirty-seven years; 85 percent were male. Females had higher HIV prevalence than males (10.2 percent vs. 3.4 percent; p =0.001). HIV cases at baseline ( n =47) most strongly clustered by drug injection sites ( Z -Score -6.173; p light district. Spatial correlates of HIV included syphilis infection, female gender, younger age, increased hours on the street per day, and higher number of injection partners. Almost all HIV seroconverters injected within a 2.5 block radius of each other immediately prior to seroconversion. Only history of syphilis infection and female gender were strongly associated with HIV in the area where incident cases injected. Directional trends suggested a largely static epidemic until July-December 2008, when HIV spread to the southeast, possibly related to intensified violence and policing that spiked in the latter half of 2008. While clustering allows for targeting interventions, the dynamic nature of epidemics suggests the importance of mobile treatment and harm reduction programs.

  3. Spatial Epidemiology of HIV among Injection Drug Users in Tijuana, Mexico

    Science.gov (United States)

    Brouwer, Kimberly C.; Rusch, Melanie L.; Weeks, John R.; Lozada, Remedios; Vera, Alicia; Magis-Rodríguez, Carlos; Strathdee, Steffanie A.

    2012-01-01

    The northwest border city of Tijuana is Mexico’s fifth largest and is experiencing burgeoning drug use and human immunodeficiency virus (HIV) epidemics. Since local geography influences disease risk, we explored the spatial distribution of HIV among injection drug users (IDUs). From 2006–2007, 1056 IDUs were recruited using respondent-driven sampling, and then followed for eighteen months. Participants underwent semi-annual surveys, mapping, and testing for HIV, tuberculosis, and syphilis. Using Average Nearest Neighbor and Getis-Ord Gi* statistics, locations where participants lived, worked, bought and injected drugs were compared with HIV status and environmental and behavioral factors. Median age was thirty-seven years; 85 percent were male. Females had higher HIV prevalence than males (10.2 percent vs. 3.4 percent; p=0.001). HIV cases at baseline (n=47) most strongly clustered by drug injection sites (Z-Score −6.173; p < 0.001), with a 16 km2 hotspot near the Mexico/U.S. border, encompassing the red-light district. Spatial correlates of HIV included syphilis infection, female gender, younger age, increased hours on the street per day, and higher number of injection partners. Almost all HIV seroconverters injected within a 2.5 block radius of each other immediately prior to seroconversion. Only history of syphilis infection and female gender were strongly associated with HIV in the area where incident cases injected. Directional trends suggested a largely static epidemic until July–December 2008, when HIV spread to the southeast, possibly related to intensified violence and policing that spiked in the latter half of 2008. While clustering allows for targeting interventions, the dynamic nature of epidemics suggests the importance of mobile treatment and harm reduction programs. PMID:23606753

  4. Negotiating sexual safety in the era of biomedical HIV prevention: relationship dynamics among male couples using pre-exposure prophylaxis.

    Science.gov (United States)

    Malone, Jowanna; Syvertsen, Jennifer L; Johnson, Blake E; Mimiaga, Matthew J; Mayer, Kenneth H; Bazzi, Angela R

    2018-06-01

    Up to two-thirds of new cases of HIV transmission between gay, bisexual and other men who have sex with men in the USA are attributed to primary relationships. Understanding the relationship dynamics and sexual agreements of male-male couples can provide insight into HIV transmission patterns and prevention needs in this population. The daily use of antiretroviral pre-exposure prophylaxis (PrEP) is highly effective in preventing HIV, but its negotiation and use within social and intimate relationship contexts remain understudied. We conducted semi-structured qualitative interviews with 20 male couples (n = 40 men) in which at least one partner was either using or in the process of initiating PrEP. Congruent with a theoretical focus on social theories of relationships and negotiated risk, couples were interviewed about relationship dynamics, trust, communication and sexual health practices, including their perception and use of PrEP. Overall, we found that couples showed heightened trust and communication when establishing open, sexual agreements and demonstrated high awareness of sexual risks and health practices in the context of PrEP use. This study demonstrates how understanding relationship dynamics can better inform HIV prevention and sexual health promotion efforts for male couples at risk of HIV.

  5. Dynamics of regulatory T-cells during pregnancy: effect of HIV infection and correlations with other immune parameters.

    Directory of Open Access Journals (Sweden)

    Kelly Richardson

    Full Text Available Regulatory T cells (Treg increase in the context of HIV infection and pregnancy. We studied Treg subpopulations in HIV-infected and uninfected women during pregnancy and their relationship with inflammation, activation and cell-mediated immunity (CMI.Blood obtained from 20 HIV-infected and 18 uninfected women during early and late gestation was used to measure Treg and activated T cells (Tact by flow cytometry; plasma cytokines and inflammatory markers by ELISA and chemoluminescence; and CMI against varicella-zoster virus (VZV by lymphocyte proliferation.Compared with uninfected women, HIV-infected participants had higher frequencies of Treg subpopulations in early pregnancy, including CD4+CD25+FoxP3+%, CD8+CD25+FoxP3+%, CD4+TGFβ+% and CD4+IL10+%. In contrast, Treg frequencies were lower during late pregnancy in HIV-infected compared with uninfected women, including CD8+TGFβ+%, CD4+CTLA4+% and CD8+CTLA4+%. VZV-CMI, which was lower in HIV-infected compared with uninfected pregnant women, was inversely correlated with CD4+FoxP3+%, CD8+FoxP3+% and CD8+TGFβ+% in HIV-infected, but not in uninfected pregnant women. β₂-microglobulin, neopterin, IL1, IL4, IL8, IL10, IFNγ and TNFα plasma concentrations as well as Tact were higher in HIV-infected compared with uninfected women throughout pregnancy. In HIV-infected, but not in uninfected women, inflammatory, Th1, Th2 and regulatory cytokines increased with higher Treg%, suggesting that inflammation and regulation have a common pathophysiologic origin in the context of HIV infection. In HIV-infected and more commonly in uninfected pregnant women, higher Treg% correlated with lower Tact%. We conclude that Treg have different dynamics during pregnancy in HIV-infected and uninfected women. Higher levels of inflammatory cytokines and lower Treg% during late pregnancy in HIV-infected women may contribute to their increased incidence of maternal-fetal morbidity.

  6. Effects of contact structure on the transient evolution of HIV virulence.

    Directory of Open Access Journals (Sweden)

    Sang Woo Park

    2017-03-01

    Full Text Available Early in an epidemic, high densities of susceptible hosts select for relatively high parasite virulence; later in the epidemic, lower susceptible densities select for lower virulence. Thus over the course of a typical epidemic the average virulence of parasite strains increases initially, peaks partway through the epidemic, then declines again. However, precise quantitative outcomes, such as the peak virulence reached and its timing, may depend sensitively on epidemiological details. Fraser et al. proposed a model for the eco-evolutionary dynamics of HIV that incorporates the tradeoffs between transmission and virulence (mediated by set-point viral load, SPVL and their heritability between hosts. Their model used implicit equations to capture the effects of partnership dynamics that are at the core of epidemics of sexually transmitted diseases. Our models combine HIV virulence tradeoffs with a range of contact models, explicitly modeling partnership formation and dissolution and allowing for individuals to transmit disease outside of partnerships. We assess summary statistics such as the peak virulence (corresponding to the maximum value of population mean log10 SPVL achieved throughout the epidemic across models for a range of parameters applicable to the HIV epidemic in sub-Saharan Africa. Although virulence trajectories are broadly similar across models, the timing and magnitude of the virulence peak vary considerably. Previously developed implicit models predicted lower virulence and slower progression at the peak (a maximum of 3.5 log10 SPVL compared both to more realistic models and to simple random-mixing models with no partnership structure at all (both with a maximum of ≈ 4.7 log10 SPVL. In this range of models, the simplest random-mixing structure best approximates the most realistic model; this surprising outcome occurs because the dominance of extra-pair contact in the realistic model swamps the effects of partnership structure.

  7. The relational dynamics of hegemonic masculinity among South African men and women in the context of HIV.

    Science.gov (United States)

    Stern, Erin; Buikema, Rosemarie

    2013-01-01

    In South Africa, the frequent positioning of men's sexual behaviours as a prime driver of the HIV epidemic has generated much interest in men's sexuality. However, the relational nature of dominant male norms that exacerbate the risk of HIV transmission is inadequately understood. This study used sexual biographies to explore how men and women negotiate gendered norms and how this affects their sexual and reproductive health (SRH). A total of 50 sexual-history interviews and 10 focus group discussions were conducted with men, and 25 sexual-history interviews with women, with participants sampled from three age categories (ages 18-24, 25-55 and 55+years), a range of cultural and racial backgrounds and urban and rural sites across five provinces in South Africa. The narratives illustrate that men and women's SRH is largely dependent on the type and quality of their relationships. Men's sexuality was regularly depicted as being detached from intimacy and uncontrollable, which was premised as being opposite from and/or superior to women's sexuality and could justify men's high-risk sexual behaviours. Yet many participants also supported gender equitable relationships and endorsed accountable and healthy SRH behaviours. The narratives reveal that HIV-risky dominant male norms should be addressed relationally for the sake of better SRH outcomes.

  8. Internalized stigma and HIV status disclosure among HIV-positive black men who have sex with men

    OpenAIRE

    Overstreet, Nicole M.; Earnshaw, Valerie A.; Kalichman, Seth C.; Quinn, Diane M.

    2012-01-01

    Black men who have sex with men (BMSM) are severely affected by the HIV epidemic, yet research on the relationship between HIV stigma and status disclosure is relatively limited among this population. Within this epidemic, internalized HIV stigma, the extent to which people living with HIV/AIDS (PLWHA) endorse the negative beliefs associated with HIV as true of themselves, can negatively shape interpersonal outcomes and have important implications for psychological and physical health. In a s...

  9. Modeling Epidemic Network Failures

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Fagertun, Anna Manolova

    2013-01-01

    This paper presents the implementation of a failure propagation model for transport networks when multiple failures occur resulting in an epidemic. We model the Susceptible Infected Disabled (SID) epidemic model and validate it by comparing it to analytical solutions. Furthermore, we evaluate...... the SID model’s behavior and impact on the network performance, as well as the severity of the infection spreading. The simulations are carried out in OPNET Modeler. The model provides an important input to epidemic connection recovery mechanisms, and can due to its flexibility and versatility be used...... to evaluate multiple epidemic scenarios in various network types....

  10. Epidemic Spreading with Heterogeneous Awareness on Human Networks

    Directory of Open Access Journals (Sweden)

    Yanling Lu

    2017-01-01

    Full Text Available The spontaneous awareness behavioral responses of individuals have a significant impact on epidemic spreading. In this paper, a modified Susceptible-Alert-Infected-Susceptible (SAIS epidemic model with heterogeneous awareness is presented to study epidemic spreading in human networks and the impact of heterogeneous awareness on epidemic dynamics. In this model, when susceptible individuals receive awareness information about the presence of epidemic from their infected neighbor nodes, they will become alert individuals with heterogeneous awareness rate. Theoretical analysis and numerical simulations show that heterogeneous awareness can enhance the epidemic threshold with certain conditions and reduce the scale of virus outbreaks compared with no awareness. What is more, for the same awareness parameter, it also shows that heterogeneous awareness can slow effectively the spreading size and does not delay the arrival time of epidemic spreading peak compared with homogeneous awareness.

  11. HIV Programs for Sex Workers: Lessons and Challenges for Developing and Delivering Programs.

    Directory of Open Access Journals (Sweden)

    David Wilson

    2015-06-01

    Full Text Available There is evidence that HIV prevention programs for sex workers, especially female sex workers, are cost-effective in several contexts, including many western countries, Thailand, India, the Democratic Republic of Congo, Kenya, and Zimbabwe. The evidence that sex worker HIV prevention programs work must not inspire complacency but rather a renewed effort to expand, intensify, and maximize their impact. The PLOS Collection "Focus on Delivery and Scale: Achieving HIV Impact with Sex Workers" highlights major challenges to scaling-up sex worker HIV prevention programs, noting the following: sex worker HIV prevention programs are insufficiently guided by understanding of epidemic transmission dynamics, situation analyses, and programmatic mapping; sex worker HIV and sexually transmitted infection services receive limited domestic financing in many countries; many sex worker HIV prevention programs are inadequately codified to ensure consistency and quality; and many sex worker HIV prevention programs have not evolved adequately to address informal sex workers, male and transgender sex workers, and mobile- and internet-based sex workers. Based on the wider collection of papers, this article presents three major clusters of recommendations: (i HIV programs focused on sex workers should be prioritized, developed, and implemented based on robust evidence; (ii national political will and increased funding are needed to increase coverage of effective sex worker HIV prevention programs in low and middle income countries; and (iii comprehensive, integrated, and rapidly evolving HIV programs are needed to ensure equitable access to health services for individuals involved in all forms of sex work.

  12. Social Media Monitoring of Discrimination and HIV Testing in Brazil, 2014-2015.

    Science.gov (United States)

    Nielsen, René Clausen; Luengo-Oroz, Miguel; Mello, Maeve B; Paz, Josi; Pantin, Colin; Erkkola, Taavi

    2017-07-01

    Big data can be used to assess perceptions about public health issues. This study assessed social media data from Twitter to inform communication campaigns to promote HIV testing and reduce discrimination related to HIV/AIDS or towards key populations to the HIV epidemic, and its potential utility to evaluate such campaigns through HIV testing uptake. Tweets from Brazil were collected from January 2014 to March 2015 and filtered by four categories of keywords including discrimination, HIV prevention, HIV testing, and HIV campaigns. In total over 100,000 geo-located tweets were extracted and analyzed. A dynamic online dashboard updated daily allowed mapping trends, anomalies and influencers, and enabled its use for feedback to campaigns, including correcting misconceptions. These results encourage the use of social networking data for improved messaging in campaigns. Clinical HIV test data was collected monthly from the city of Curitiba and compared to the number of tweets mapped to the city showing a moderate positive correlation (r = 0.39). Results are limited due to the availability of the HIV testing data. The potential of social media as a proxy for HIV testing uptake needs further validation, which can only be done with higher frequency and higher spatial granularity of service delivery data, enabling comparisons with the social media data. Such timely information could empower early response immediate media messaging to support programmatic efforts, such as HIV prevention, testing, and treatment scale up.

  13. HIV Programs for Sex Workers: Lessons and Challenges for Developing and Delivering Programs.

    Science.gov (United States)

    Wilson, David

    2015-06-01

    There is evidence that HIV prevention programs for sex workers, especially female sex workers, are cost-effective in several contexts, including many western countries, Thailand, India, the Democratic Republic of Congo, Kenya, and Zimbabwe. The evidence that sex worker HIV prevention programs work must not inspire complacency but rather a renewed effort to expand, intensify, and maximize their impact. The PLOS Collection "Focus on Delivery and Scale: Achieving HIV Impact with Sex Workers" highlights major challenges to scaling-up sex worker HIV prevention programs, noting the following: sex worker HIV prevention programs are insufficiently guided by understanding of epidemic transmission dynamics, situation analyses, and programmatic mapping; sex worker HIV and sexually transmitted infection services receive limited domestic financing in many countries; many sex worker HIV prevention programs are inadequately codified to ensure consistency and quality; and many sex worker HIV prevention programs have not evolved adequately to address informal sex workers, male and transgender sex workers, and mobile- and internet-based sex workers. Based on the wider collection of papers, this article presents three major clusters of recommendations: (i) HIV programs focused on sex workers should be prioritized, developed, and implemented based on robust evidence; (ii) national political will and increased funding are needed to increase coverage of effective sex worker HIV prevention programs in low and middle income countries; and (iii) comprehensive, integrated, and rapidly evolving HIV programs are needed to ensure equitable access to health services for individuals involved in all forms of sex work.

  14. Russia is on brink of AIDS epidemic.

    Science.gov (United States)

    Ingram, M

    1996-08-03

    Russia, and in particular Moscow, is on the brink of an AIDS epidemic, the president of the Russian Medical Academy told doctors gathered in Moscow for a national AIDS seminar. Although Russia has officially registered only 1269 cases of HIV infection, a quarter of them in Moscow, and 193 deaths since the first case appeared in Russia in 1987, health officials are alarmed by the recent rise in the rate of infection. In 1995, 200 new cases were registered, but 205 cases had already been registered in the first 6 months of 1996. The rapid spread of intravenous drug use is the main factor contributing to the rise in HIV infection. According to the head of the Russian AIDS Center, the real number of people infected with HIV in Russia is 3-4 times higher than official numbers, while AIDS activists believe that the real figure is 10-20 times higher. Russia has traditionally blamed its AIDS problem on foreigners and introduced an obligatory HIV test as a visa requirement for long-term visitors. Now neighboring Ukraine and Belarus are being blamed for the latest crisis. Of 1000 known intravenous drug users tested in Svetlogorsk, Belarus, 158 are HIV positive, with 20 results still outstanding. Previously, only 130 people in Belarus were known to be infected with HIV. In the Ukraine, where HIV testing has shown that over 5000 people are HIV positive and where a further 20,000 are estimated to be infected, a special subtype of HIV-1 has been discovered. In 1995 there were 1021 new cases of HIV infection, but in the first 4 months of this year there were 1805 new cases. Although the chief AIDS specialist at Russia's health ministry agrees that health education is more important than scare tactics against foreigners, in 1995 the health ministry received only 49% of the funds allocated for national AIDS education.

  15. Everyday social dynamics and cultural drivers of women's experiences with HIV/AIDS : voices from Buhaya, Tanzania

    NARCIS (Netherlands)

    Foster Githinji, V.E.

    2015-01-01

    Everyday social dynamics and cultural drivers of women’s experiences with HIV/AIDS: voices from Buhaya, Tanzania is based on ethnographic research conducted in the village of Nsisha in northwestern Tanzania. Like most households in this region, Nsisha has been indirectly or

  16. Applying the Dynamic Social Systems Model to HIV Prevention in a Rural African Context: The Maasai and the "Esoto" Dance

    Science.gov (United States)

    Siegler, Aaron J.; Mbwambo, Jessie K.; DiClemente, Ralph J.

    2013-01-01

    This study applied the Dynamic Social Systems Model (DSSM) to the issue of HIV risk among the Maasai tribe of Tanzania, using data from a cross-sectional, cluster survey among 370 randomly selected participants from Ngorongoro and Siha Districts. A culturally appropriate survey instrument was developed to explore traditions reportedly coadunate…

  17. Epidemiology of HIV among female sex workers, their clients, men who have sex with men and people who inject drugs in West and Central Africa

    Science.gov (United States)

    Papworth, Erin; Ceesay, Nuha; An, Louis; Thiam-Niangoin, Marguerite; Ky-Zerbo, Odette; Holland, Claire; Dramé, Fatou Maria; Grosso, Ashley; Diouf, Daouda; Baral, Stefan D

    2013-01-01

    Introduction The West and Central Africa (WCA) sub-region is the most populous region of sub-Saharan Africa (SSA), with an estimated population of 356 million living in 24 countries. The HIV epidemic in WCA appears to have distinct dynamics compared to the rest of SSA, being more concentrated among key populations such as female sex workers (FSWs), men who have sex with men (MSM), people who inject drugs (PWID) and clients of FSWs. To explore the epidemiology of HIV in the region, a systematic review of HIV literature among key populations in WCA was conducted since the onset of the HIV epidemic. Methods We searched the databases PubMed, CINAHL and others for peer-reviewed articles regarding FSWs, MSM and PWID in 24 countries with no date restriction. Inclusion criteria were sensitive and focused on inclusion of any HIV prevalence data among key populations. HIV prevalence was pooled, and in each country key themes were extracted from the literature. Results The search generated 885 titles, 214 abstracts and 122 full articles, of which 76 met inclusion and exclusion criteria providing HIV prevalence data. There were 60 articles characterizing the burden of disease among FSWs, eight for their clients, one for both, six for MSM and one for PWID. The pooled HIV prevalence among FSWs was 34.9% (n=14,388/41,270), among their clients was 7.3% (n=435/5986), among MSM was 17.7% (n=656/3714) and among PWID from one study in Nigeria was 3.8% (n=56/1459). Conclusions The disproportionate burden of HIV among FSWs appears to be consistent from the beginning of the HIV epidemic in WCA. While there are less data for other key populations such as clients of FSWs and MSM, the prevalence of HIV is higher among these men compared to other men in the region. There have been sporadic reports among PWID, but limited research on the burden of HIV among these men and women. These data affirm that the HIV epidemic in WCA appears to be far more concentrated among key populations than the

  18. Viral persistence, latent reservoir, and blips: a review on HIV-1 dynamics and modeling during HAART and related treatment implications

    Energy Technology Data Exchange (ETDEWEB)

    Rong, Libin [Los Alamos National Laboratory; Perelson, Alan [Los Alamos National Laboratory

    2008-01-01

    HIV-1 eradication from infected individuals has not been achieved with the use of highly active antiretroviral therapy (HAART) for a prolonged period of time. The cellular reservoir for HIV-1 in resting memory CD4{sup +} T cells remains a major obstacle to viral elimination. The reservoir does not decay significantly over long periods of time as is able to release replication competent HIV-1 upon cell activation. Residual ongoing viral replication may likely occur in many patients because low levels of virus can be detected in plasma by sensitive assays and transient episodes of viremia, or HIV-1 blips, are often observed in patients even with successful viral suppression for many years. Here we review our current knowledge of the factors contributing to viral persistence, the latent reservoir, and blips, and mathematical models developed to explore them and their relationships. We show how mathematical modeling can help improve our understanding of HIV-1 dynamics in patients on HAART and the quantitative events underlying HIV-1 latency, reservoir stability, low-level viremic persistence, and emergence of intermittent viral blips. We also discuss treatment implications related to these studies.

  19. University students and HIV in Namibia: an HIV prevalence survey and a knowledge and attitude survey

    NARCIS (Netherlands)

    de Beer, Ingrid H.; Gelderblom, Huub C.; Schellekens, Onno; Gaeb, Esegiel; van Rooy, Gert; McNally, Alta; Wit, Ferdinand W.; Rinke de Wit, Tobias F.

    2012-01-01

    Background: With an overall adult HIV prevalence of 15.3%, Namibia is facing one of the largest HIV epidemics in Africa. Young people aged 20 to 34 years constitute one of the groups at highest risk of HIV infection in Namibia. However, little is known about the impact of HIV on this group and its

  20. HIV Risk Behavior and Access to Services: What Predicts HIV Testing among Heterosexually Active Homeless Men?

    Science.gov (United States)

    Wenzel, Suzanne L.; Rhoades, Harmony; Tucker, Joan S.; Golinelli, Daniela; Kennedy, David P.; Zhou, Annie; Ewing, Brett

    2012-01-01

    HIV is a serious epidemic among homeless persons, where rates of infection are estimated to be three times higher than in the general population. HIV testing is an effective tool for reducing HIV transmission and for combating poor HIV/AIDS health outcomes that disproportionately affect homeless persons, however, little is known about the HIV…

  1. Situating experiences of HIV-related stigma in Swaziland.

    Science.gov (United States)

    Root, R

    2010-01-01

    With the world's highest antenatal HIV prevalence rate (39.2%), Swaziland has also been described as among the most stigmatising. Yet, only recently was an anti-HIV stigma and discrimination (S&D) platform included in the government's National Multisectoral HIV and AIDS Policy. This study draws on a medical anthropological project in rural Swaziland to examine experiences of stigma among people living with HIV/AIDS (PLWH). Qualitative methods included a semi-structured questionnaire and interviews (n=40) to identify patterns of stigma across three domains: verbal, physical and social. Key informant interviews (n=5) were conducted with health personnel and support group leaders. Descriptive statistics were situated within a thematic analysis of open-ended content. Among the findings, participants reported extensive HIV-related rumouring (36.4%) and pejorative name-calling (37.5%). Nearly one in five (18.2%) could no longer partake of family meals. Homesteads, which are an organising principle of Swazi life, were often markedly stigmatising environments. In contrast to documented discrimination in health care settings, the health centre emerged as a space where PLWH could share information and support. Given the UNAIDS call for national partners to 'know your epidemic' by tracking the prevalence of HIV-related S&D, results from this study suggested that unless 'knowing your epidemic' includes the lived experiences of HIV stigma that blister into discernible patterns, effectiveness of national initiatives is likely to be limited. Multidisciplinary and locale-specific studies are especially well suited in examining the cultural dynamics of HIV stigma and in providing grounded data that deepen the impact of comprehensive HIV/AIDS policies and programming.

  2. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... in recent years, HIV is no longer a death sentence, as it was when the epidemic began. ... also be spread this way. Hepatitis C can cause liver disease and permanent liver damage. Poor judgment ...

  3. Visualization of early events in acetic acid denaturation of HIV-1 protease: a molecular dynamics study.

    Directory of Open Access Journals (Sweden)

    Aditi Narendra Borkar

    Full Text Available Protein denaturation plays a crucial role in cellular processes. In this study, denaturation of HIV-1 Protease (PR was investigated by all-atom MD simulations in explicit solvent. The PR dimer and monomer were simulated separately in 9 M acetic acid (9 M AcOH solution and water to study the denaturation process of PR in acetic acid environment. Direct visualization of the denaturation dynamics that is readily available from such simulations has been presented. Our simulations in 9 M AcOH reveal that the PR denaturation begins by separation of dimer into intact monomers and it is only after this separation that the monomer units start denaturing. The denaturation of the monomers is flagged off by the loss of crucial interactions between the α-helix at C-terminal and surrounding β-strands. This causes the structure to transit from the equilibrium dynamics to random non-equilibrating dynamics. Residence time calculations indicate that denaturation occurs via direct interaction of the acetic acid molecules with certain regions of the protein in 9 M AcOH. All these observations have helped to decipher a picture of the early events in acetic acid denaturation of PR and have illustrated that the α-helix and the β-sheet at the C-terminus of a native and functional PR dimer should maintain both the stability and the function of the enzyme and thus present newer targets for blocking PR function.

  4. Large Variations in HIV-1 Viral Load Explained by Shifting-Mosaic Metapopulation Dynamics

    Science.gov (United States)

    Lythgoe, Katrina A.; Blanquart, François

    2016-01-01

    The viral population of HIV-1, like many pathogens that cause systemic infection, is structured and differentiated within the body. The dynamics of cellular immune trafficking through the blood and within compartments of the body has also received wide attention. Despite these advances, mathematical models, which are widely used to interpret and predict viral and immune dynamics in infection, typically treat the infected host as a well-mixed homogeneous environment. Here, we present mathematical, analytical, and computational results that demonstrate that consideration of the spatial structure of the viral population within the host radically alters predictions of previous models. We study the dynamics of virus replication and cytotoxic T lymphocytes (CTLs) within a metapopulation of spatially segregated patches, representing T cell areas connected by circulating blood and lymph. The dynamics of the system depend critically on the interaction between CTLs and infected cells at the within-patch level. We show that for a wide range of parameters, the system admits an unexpected outcome called the shifting-mosaic steady state. In this state, the whole body’s viral population is stable over time, but the equilibrium results from an underlying, highly dynamic process of local infection and clearance within T-cell centers. Notably, and in contrast to previous models, this new model can explain the large differences in set-point viral load (SPVL) observed between patients and their distribution, as well as the relatively low proportion of cells infected at any one time, and alters the predicted determinants of viral load variation. PMID:27706164

  5. Molecular dynamics simulations of conformation changes of HIV-1 regulatory protein on graphene

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Daohui; Li, Libo; He, Daohang; Zhou, Jian, E-mail: jianzhou@scut.edu.cn

    2016-07-30

    Graphical abstract: Preferential adsorption of Vpr13-33 on graphene accompanied by early conformational change from α-helix to β-sheet structures was observed by molecular simulations. This work presents the molecular mechanism of graphene-induced peptide conformational alteration and sheds light on developing graphene-based materials to inhibit HIV. - Highlights: • Graphene induced early structural transition of Vpr13-33 is studied by MD simulations. • Both π-π stacking and hydrophobic interactions orchestrate the peptide adsorption. • Vpr has an increased propensity of β-sheet content on graphene surface. • To develop graphene-based materials to inhibit HIV is possible. - Abstract: The fragment of viral protein R (Vpr), Vpr13-33, plays an important role in regulating nuclear importing of HIV genes through channel formation in which it adopts a leucine-zipper-like alpha-helical conformation. A recent experimental study reported that helical Vpr13-33 would transform to β-sheet or random coil structures and aggregate on the surface of graphene or graphene oxide through hydrophobic interactions. Due to experimental limitations, however, there is still a considerable lack of understanding on the adsorption dynamics at the early stage of the conformational transition at water-graphene interface and the underlying driving force at molecular level. In this study, atomistic molecular dynamics simulations were used to explore the conformation transition phenomena. Vpr13-33 kept α-helical structure in solution, but changed to β-sheet structure when strongly adsorbed onto graphene. Preferential adsorption of Vpr13-33 on graphene is dominated by hydrophobic interactions. The cluster analysis identified the most significant populated conformation and the early stage of structure conversion from α-helical to β-sheet was found, but the full β-sheet propagation was not observed. Free energy landscape analysis further complemented the transformation analysis of

  6. Molecular dynamics simulations of conformation changes of HIV-1 regulatory protein on graphene

    International Nuclear Information System (INIS)

    Zhao, Daohui; Li, Libo; He, Daohang; Zhou, Jian

    2016-01-01

    Graphical abstract: Preferential adsorption of Vpr13-33 on graphene accompanied by early conformational change from α-helix to β-sheet structures was observed by molecular simulations. This work presents the molecular mechanism of graphene-induced peptide conformational alteration and sheds light on developing graphene-based materials to inhibit HIV. - Highlights: • Graphene induced early structural transition of Vpr13-33 is studied by MD simulations. • Both π-π stacking and hydrophobic interactions orchestrate the peptide adsorption. • Vpr has an increased propensity of β-sheet content on graphene surface. • To develop graphene-based materials to inhibit HIV is possible. - Abstract: The fragment of viral protein R (Vpr), Vpr13-33, plays an important role in regulating nuclear importing of HIV genes through channel formation in which it adopts a leucine-zipper-like alpha-helical conformation. A recent experimental study reported that helical Vpr13-33 would transform to β-sheet or random coil structures and aggregate on the surface of graphene or graphene oxide through hydrophobic int