WorldWideScience

Sample records for hiv population size

  1. Selection dramatically reduces effective population size in HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Mittler John E

    2008-05-01

    Full Text Available Abstract Background In HIV-1 evolution, a 100–100,000 fold discrepancy between census size and effective population size (Ne has been noted. Although it is well known that selection can reduce Ne, high in vivo mutation and recombination rates complicate attempts to quantify the effects of selection on HIV-1 effective size. Results We use the inbreeding coefficient and the variance in allele frequency at a linked neutral locus to estimate the reduction in Ne due to selection in the presence of mutation and recombination. With biologically realistic mutation rates, the reduction in Ne due to selection is determined by the strength of selection, i.e., the stronger the selection, the greater the reduction. However, the dependence of Ne on selection can break down if recombination rates are very high (e.g., r ≥ 0.1. With biologically likely recombination rates, our model suggests that recurrent selective sweeps similar to those observed in vivo can reduce within-host HIV-1 effective population sizes by a factor of 300 or more. Conclusion Although other factors, such as unequal viral reproduction rates and limited migration between tissue compartments contribute to reductions in Ne, our model suggests that recurrent selection plays a significant role in reducing HIV-1 effective population sizes in vivo.

  2. Study design and the estimation of the size of key populations at risk of HIV: lessons from Viet Nam.

    Science.gov (United States)

    Safarnejad, Ali; Groot, Wim; Pavlova, Milena

    2018-01-30

    Estimation of the size of populations at risk of HIV is a key activity in the surveillance of the HIV epidemic. The existing framework for considering future research needs may provide decision-makers with a basis for a fair process of deciding on the methods of the estimation of the size of key populations at risk of HIV. This study explores the extent to which stakeholders involved with population size estimation agree with this framework, and thus, the study updates the framework. We conducted 16 in-depth interviews with key informants from city and provincial governments, NGOs, research institutes, and the community of people at risk of HIV. Transcripts were analyzed and reviewed for significant statements pertaining to criteria. Variations and agreement around criteria were analyzed, and emerging criteria were validated against the existing framework. Eleven themes emerged which are relevant to the estimation of the size of populations at risk of HIV in Viet Nam. Findings on missing criteria, inclusive participation, community perspectives and conflicting weight and direction of criteria provide insights for an improved framework for the prioritization of population size estimation methods. The findings suggest that the exclusion of community members from decision-making on population size estimation methods in Viet Nam may affect the validity, use, and efficiency of the evidence generated. However, a wider group of decision-makers, including community members among others, may introduce diverse definitions, weight and direction of criteria. Although findings here may not apply to every country with a transitioning economy or to every emerging epidemic, the principles of fair decision-making, value of community participation in decision-making and the expected challenges faced, merit consideration in every situation.

  3. Size, Composition, and Evolution of HIV DNA Populations during Early Antiretroviral Therapy and Intensification with Maraviroc.

    Science.gov (United States)

    Chaillon, Antoine; Gianella, Sara; Lada, Steven M; Perez-Santiago, Josué; Jordan, Parris; Ignacio, Caroline; Karris, Maile; Richman, Douglas D; Mehta, Sanjay R; Little, Susan J; Wertheim, Joel O; Smith, Davey M

    2018-02-01

    Residual viremia is common during antiretroviral therapy (ART) and could be caused by ongoing low-level virus replication or by release of viral particles from infected cells. ART intensification should impact ongoing viral propagation but not virion release. Eighteen acutely infected men were enrolled in a randomized controlled trial and monitored for a median of 107 weeks. Participants started ART with ( n = 9) or without ( n = 9) intensification with maraviroc (MVC) within 90 days of infection. Levels of HIV DNA and cell-free RNA were quantified by droplet digital PCR. Deep sequencing of C2-V3 env , gag , and pol (454 Roche) was performed on longitudinally collected plasma and peripheral blood mononuclear cell (PBMC) samples while on ART. Sequence data were analyzed for evidence of evolution by (i) molecular diversity analysis, (ii) nonparametric test for panmixia, and (iii) tip date randomization within a Bayesian framework. There was a longitudinal decay of HIV DNA after initiation of ART with no difference between MVC intensification groups (-0.08 ± 0.01 versus -0.09 ± 0.01 log 10 copies/week in MVC + versus MVC - groups; P = 0.62). All participants had low-level residual viremia (median, 2.8 RNA copies/ml). Across participants, medians of 56 (interquartile range [IQR], 36 to 74), 29 (IQR, 25 to 35), and 40 (IQR, 31 to 54) haplotypes were generated for env , gag , and pol regions, respectively. There was no clear evidence of viral evolution during ART and no difference in viral diversity or population structure from individuals with or without MVC intensification. Further efforts focusing on elucidating the mechanism(s) of viral persistence in various compartments using recent sequencing technologies are still needed, and potential low-level viral replication should always be considered in cure strategies. IMPORTANCE Residual viremia is common among HIV-infected people on ART. It remains controversial if this viremia is a consequence of propagating

  4. Taking multiple infections of cells and recombination into account leads to small within-host effective-population-size estimates of HIV-1.

    Directory of Open Access Journals (Sweden)

    Rajesh Balagam

    2011-01-01

    Full Text Available Whether HIV-1 evolution in infected individuals is dominated by deterministic or stochastic effects remains unclear because current estimates of the effective population size of HIV-1 in vivo, N(e, are widely varying. Models assuming HIV-1 evolution to be neutral estimate N(e~10²-10⁴, smaller than the inverse mutation rate of HIV-1 (~10⁵, implying the predominance of stochastic forces. In contrast, a model that includes selection estimates N(e>10⁵, suggesting that deterministic forces would hold sway. The consequent uncertainty in the nature of HIV-1 evolution compromises our ability to describe disease progression and outcomes of therapy. We perform detailed bit-string simulations of viral evolution that consider large genome lengths and incorporate the key evolutionary processes underlying the genomic diversification of HIV-1 in infected individuals, namely, mutation, multiple infections of cells, recombination, selection, and epistatic interactions between multiple loci. Our simulations describe quantitatively the evolution of HIV-1 diversity and divergence in patients. From comparisons of our simulations with patient data, we estimate N(e~10³-10⁴, implying predominantly stochastic evolution. Interestingly, we find that N(e and the viral generation time are correlated with the disease progression time, presenting a route to a priori prediction of disease progression in patients. Further, we show that the previous estimate of N(e>10⁵ reduces as the frequencies of multiple infections of cells and recombination assumed increase. Our simulations with N(e~10³-10⁴ may be employed to estimate markers of disease progression and outcomes of therapy that depend on the evolution of viral diversity and divergence.

  5. A Method to Estimate the Size and Characteristics of HIV-positive Populations Using an Individual-based Stochastic Simulation Model

    DEFF Research Database (Denmark)

    Nakagawa, Fumiyo; van Sighem, Ard; Thiebaut, Rodolphe

    2016-01-01

    % plausibility range: 39,900-45,560) men who have sex with men were estimated to be living with HIV in the UK, of whom 10,400 (6,160-17,350) were undiagnosed. There were an estimated 3,210 (1,730-5,350) infections per year on average between 2010 and 2013. Sixty-two percent of the total HIV-positive population......It is important not only to collect epidemiologic data on HIV but to also fully utilize such information to understand the epidemic over time and to help inform and monitor the impact of policies and interventions. We describe and apply a novel method to estimate the size and characteristics of HIV-positive...... populations. The method was applied to data on men who have sex with men living in the UK and to a pseudo dataset to assess performance for different data availability. The individual-based simulation model was calibrated using an approximate Bayesian computation-based approach. In 2013, 48,310 (90...

  6. Risk behaviors, prevalence of HIV and hepatitis C virus infection and population size of current injection drug users in a China-Myanmar border city: results from a Respondent-Driven Sampling Survey in 2012.

    Science.gov (United States)

    Li, Lei; Assanangkornchai, Sawitri; Duo, Lin; McNeil, Edward; Li, Jianhua

    2014-01-01

    Injection drug use has been the major cause of HIV/AIDS in China in the past two decades. We measured the prevalences of HIV and hepatitis C virus (HCV) prevalence and their associated risk factors among current injection drug users (IDUs) in Ruili city, a border region connecting China with Myanmar that has been undergoing serious drug use and HIV spread problems. An estimate of the number of current IDUs is also presented. In 2012, Chinese IDUs who had injected within the past six months and aged ≥ 18 years were recruited using a respondent-driven sampling (RDS) technique. Participants underwent interviews and serological testing for HIV, HBV, HCV and syphilis. Logistic regression indentified factors associated with HIV and HCV infections. Multiplier method was used to obtain an estimate of the size of the current IDU population via combining available service data and findings from our survey. Among 370 IDUs recruited, the prevalence of HIV and HCV was 18.3% and 41.5%, respectively. 27.1% of participants had shared a needle/syringe in their lifetime. Consistent condom use rates were low among both regular (6.8%) and non-regular (30.4%) partners. Factors independently associated with being HIV positive included HCV infection, having a longer history of injection drug use and experience of needle/syringe sharing. Participants with HCV infection were more likely to be HIV positive, have injected more types of drugs, have shared other injection equipments and have unprotected sex with regular sex partners. The estimated number of current IDUs in Ruili city was 2,714 (95% CI: 1,617-5,846). IDUs may continue to be a critical subpopulation for transmission of HIV and other infections in this region because of the increasing population and persistent high risk of injection and sexual behaviours. Developing innovative strategies that can improve accessibility of current harm reduction services and incorporate more comprehensive contents is urgently needed.

  7. HIV testing in the Danish population

    DEFF Research Database (Denmark)

    Lemcke, Asja; Kjøller, Mette; Ekholm, Ola

    2007-01-01

    AIMS: To describe the accumulated prevalence of HIV testing in the Danish population until and including the year 2000. METHODS: The study was based on nationally representative data from the Danish Health Interview Survey 2000. Multiple logistic regression analysis investigated the association...... between HIV testing and background variables, such as gender, age, marital status, educational level, and sexual orientation. RESULTS: Overall 28.5% of the Danish population aged over 16 years have "ever been tested for HIV". More females (29.4%) than males (27.6%) were tested; 12.6% might not be aware...... of their blood being HIV tested when donating blood. More males (17.1%) than females (13.8%) had donated blood after 1985. Although males 30-39 years old were the most tested, males 50-59 years old had the highest odds of having donated blood after 1985. Concerning education, the less education one had, the less...

  8. Factors Associated with Variations in Population HIV Prevalence across West Africa: Findings from an Ecological Analysis

    Science.gov (United States)

    Prudden, Holly J.; Beattie, Tara S.; Bobrova, Natalia; Panovska-Griffiths, Jasmina; Mukandavire, Zindoga; Gorgens, Marelize; Wilson, David; Watts, Charlotte H.

    2015-01-01

    Background Population HIV prevalence across West Africa varies substantially. We assess the national epidemiological and behavioural factors associated with this. Methods National, urban and rural data on HIV prevalence, the percentage of younger (15–24) and older (25–49) women and men reporting multiple (2+) partners in the past year, HIV prevalence among female sex workers (FSWs), men who have bought sex in the past year (clients), and ART coverage, were compiled for 13 countries. An Ecological analysis using linear regression assessed which factors are associated with national variations in population female and male HIV prevalence, and with each other. Findings National population HIV prevalence varies between 0 4–2 9% for men and 0 4–5.6% for women. ART coverage ranges from 6–23%. National variations in HIV prevalence are not shown to be associated with variations in HIV prevalence among FSWs or clients. Instead they are associated with variations in the percentage of younger and older males and females reporting multiple partners. HIV prevalence is weakly negatively associated with ART coverage, implying it is not increased survival that is the cause of variations in HIV prevalence. FSWs and younger female HIV prevalence are associated with client population sizes, especially older men. Younger female HIV prevalence is strongly associated with older male and female HIV prevalence. Interpretation In West Africa, population HIV prevalence is not significantly higher in countries with high FSW HIV prevalence. Our analysis suggests, higher prevalence occurs where more men buy sex, and where a higher percentage of younger women, and older men and women have multiple partnerships. If a sexual network between clients and young females exists, clients may potentially bridge infection to younger females. HIV prevention should focus both on commercial sex and transmission between clients and younger females with multiple partners. PMID:26698854

  9. Factors Associated with Variations in Population HIV Prevalence across West Africa: Findings from an Ecological Analysis.

    Directory of Open Access Journals (Sweden)

    Holly J Prudden

    Full Text Available Population HIV prevalence across West Africa varies substantially. We assess the national epidemiological and behavioural factors associated with this.National, urban and rural data on HIV prevalence, the percentage of younger (15-24 and older (25-49 women and men reporting multiple (2+ partners in the past year, HIV prevalence among female sex workers (FSWs, men who have bought sex in the past year (clients, and ART coverage, were compiled for 13 countries. An Ecological analysis using linear regression assessed which factors are associated with national variations in population female and male HIV prevalence, and with each other.National population HIV prevalence varies between 0 4-2 9% for men and 0 4-5.6% for women. ART coverage ranges from 6-23%. National variations in HIV prevalence are not shown to be associated with variations in HIV prevalence among FSWs or clients. Instead they are associated with variations in the percentage of younger and older males and females reporting multiple partners. HIV prevalence is weakly negatively associated with ART coverage, implying it is not increased survival that is the cause of variations in HIV prevalence. FSWs and younger female HIV prevalence are associated with client population sizes, especially older men. Younger female HIV prevalence is strongly associated with older male and female HIV prevalence.In West Africa, population HIV prevalence is not significantly higher in countries with high FSW HIV prevalence. Our analysis suggests, higher prevalence occurs where more men buy sex, and where a higher percentage of younger women, and older men and women have multiple partnerships. If a sexual network between clients and young females exists, clients may potentially bridge infection to younger females. HIV prevention should focus both on commercial sex and transmission between clients and younger females with multiple partners.

  10. Anti-HIV Antibody Responses and the HIV Reservoir Size during Antiretroviral Therapy.

    Directory of Open Access Journals (Sweden)

    Sulggi A Lee

    Full Text Available A major challenge to HIV eradication strategies is the lack of an accurate measurement of the total burden of replication-competent HIV (the "reservoir". We assessed the association of anti-HIV antibody responses and the estimated size of the reservoir during antiretroviral therapy (ART.We evaluated anti-HIV antibody profiles using luciferase immunoprecipitation systems (LIPS assay in relation to several blood-based HIV reservoir measures: total and 2-LTR DNA (rtPCR or droplet digital PCR; integrated DNA (Alu PCR; unspliced RNA (rtPCR, multiply-spliced RNA (TILDA, residual plasma HIV RNA (single copy PCR, and replication-competent virus (outgrowth assay. We also assessed total HIV DNA and RNA in gut-associated lymphoid tissue (rtPCR. Spearman correlations and linear regressions were performed using log-transformed blood- or tissue-based reservoir measurements as predictors and log-transformed antibody levels as outcome variables.Among 51 chronically HIV-infected ART-suppressed participants (median age = 57, nadir CD4+ count = 196 cells/mm3, ART duration = 9 years, the most statistically significant associations were between antibody responses to integrase and HIV RNA in gut-associated lymphoid tissue (1.17 fold-increase per two-fold RNA increase, P = 0.004 and between antibody responses to matrix and integrated HIV DNA in resting CD4+ T cells (0.35 fold-decrease per two-fold DNA increase, P = 0.003. However, these associations were not statistically significant after a stringent Bonferroni-adjustment of P<0.00045. Multivariate models including age and duration of ART did not markedly alter results.Our findings suggest that anti-HIV antibody responses may reflect the size of the HIV reservoir during chronic treated HIV disease, possibly via antigen recognition in reservoir sites. Larger, prospective studies are needed to validate the utility of antibody levels as a measure of the total body burden of HIV during treatment.

  11. Determinants of HIV/AIDS in armed conflict populations.

    Science.gov (United States)

    Omare, Danvas; Kanekar, Amar

    2011-03-01

    More than 40 million people worldwide have been infected with human immunodeficiency virus (HIV) since it was first reported in 1981. Over 25 million of these have lost their lives to the disease. Most of the studies related to HIV/AIDS have been conducted in stable populations across the globe. Few of these studies have been devoted to displaced populations, particularly those in areas of conflict. Displaced populations that are forced to leave their homes in most cases find themselves in unfamiliar territories, often poor and hungry. Many of them become refugees and internally displaced people (IDPs). The objective of this review was to address a number of different social determinants of HIV/AIDS in displaced populations in areas of conflict. A comprehensive review of peer reviewed literature published in English between 1990 and 2010 obtained through an open search of PUBMED database using key words such as HIV and war , HIV/AIDS and conflict , AIDS and security was conducted. Twelve different studies that looked at the implications of HIV/AIDS in conflict or displaced populations were retrieved. The review revealed that there were various factors influencing conflict and HIV/AIDS such as forced population displacement, breakdown of traditional sexual norms, lack of health infrastructure, and poverty and powerlessness of women and children. Social determinants of increased HIV/AIDS prevalence in displaced populations are scarcity of food, poverty, insecurity of displaced populations and gender power differentials.

  12. Determinants of HIV/AIDS in armed conflict populations

    Directory of Open Access Journals (Sweden)

    Danvas Omare

    2011-02-01

    Full Text Available More than 40 million people worldwide have been infected with human immunodeficiency virus (HIV since it was first reported in 1981. Over 25 million of these have lost their lives to the disease. Most of the studies related to HIV/AIDS have been conducted in stable populations across the globe. Few of these studies have been devoted to displaced populations, particularly those in areas of conflict. Displaced populations that are forced to leave their homes in most cases find themselves in unfamiliar territories, often poor and hungry. Many of them become refugees and internally displaced people (IDPs. The objective of this review was to address a number of different social determinants of HIV/AIDS in displaced populations in areas of conflict. A comprehensive review of peer reviewed literature published in English between 1990 and 2010 obtained through an open search of PUBMED database using key words such as “HIV and war”, “HIV/AIDS and conflict”, “AIDS and security” was conducted. Twelve different studies that looked at the implications of HIV/AIDS in conflict or displaced populations were retrieved. The review revealed that there were various factors influencing conflict and HIV/AIDS such as forced population displacement, breakdown of traditional sexual norms, lack of health infrastructure, and poverty and powerlessness of women and children. Social determinants of increased HIV/AIDS prevalence in displaced populations are scarcity of food, poverty, insecurity of displaced populations and gender power differentials.

  13. Estimation of the size of the female sex worker population in Rwanda using three different methods.

    Science.gov (United States)

    Mutagoma, Mwumvaneza; Kayitesi, Catherine; Gwiza, Aimé; Ruton, Hinda; Koleros, Andrew; Gupta, Neil; Balisanga, Helene; Riedel, David J; Nsanzimana, Sabin

    2015-10-01

    HIV prevalence is disproportionately high among female sex workers compared to the general population. Many African countries lack useful data on the size of female sex worker populations to inform national HIV programmes. A female sex worker size estimation exercise using three different venue-based methodologies was conducted among female sex workers in all provinces of Rwanda in August 2010. The female sex worker national population size was estimated using capture-recapture and enumeration methods, and the multiplier method was used to estimate the size of the female sex worker population in Kigali. A structured questionnaire was also used to supplement the data. The estimated number of female sex workers by the capture-recapture method was 3205 (95% confidence interval: 2998-3412). The female sex worker size was estimated at 3348 using the enumeration method. In Kigali, the female sex worker size was estimated at 2253 (95% confidence interval: 1916-2524) using the multiplier method. Nearly 80% of all female sex workers in Rwanda were found to be based in the capital, Kigali. This study provided a first-time estimate of the female sex worker population size in Rwanda using capture-recapture, enumeration, and multiplier methods. The capture-recapture and enumeration methods provided similar estimates of female sex worker in Rwanda. Combination of such size estimation methods is feasible and productive in low-resource settings and should be considered vital to inform national HIV programmes. © The Author(s) 2015.

  14. A systematic review of measures of HIV/AIDS stigma in paediatric HIV-infected and HIV-affected populations

    Science.gov (United States)

    McAteer, Carole Ian; Truong, Nhan-Ai Thi; Aluoch, Josephine; Deathe, Andrew Roland; Nyandiko, Winstone M; Marete, Irene; Vreeman, Rachel Christine

    2016-01-01

    Introduction HIV-related stigma impacts the quality of life and care management of HIV-infected and HIV-affected individuals, but how we measure stigma and its impact on children and adolescents has less often been described. Methods We conducted a systematic review of studies that measured HIV-related stigma with a quantitative tool in paediatric HIV-infected and HIV-affected populations. Results and discussion Varying measures have been used to assess stigma in paediatric populations, with most studies utilizing the full or variant form of the HIV Stigma Scale that has been validated in adult populations and utilized with paediatric populations in Africa, Asia and the United States. Other common measures included the Perceived Public Stigma Against Children Affected by HIV, primarily utilized and validated in China. Few studies implored item validation techniques with the population of interest, although scales were used in a different cultural context from the origin of the scale. Conclusions Many stigma measures have been used to assess HIV stigma in paediatric populations, globally, but few have implored methods for cultural adaptation and content validity. PMID:27717409

  15. Introduction of HIV type 1 into an isolated population

    DEFF Research Database (Denmark)

    Madsen, Tina V; Leitner, Thomas; Lohse, Nicolai

    2007-01-01

    Introduction of HIV-1 into a population may not always give rise to a subsequent epidemic. Greenland is an isolated and sparsely populated island in The Danish Kingdom. We aimed to estimate the number of introductions of HIV-1 into Greenland, the number of subsequent epidemics, and the countries...... from which the virus was introduced. Phylogenetic analyses were performed on three regions of HIV-1 (gag, pol, and env) in samples from 70 Greenlandic patients. Furthermore, we included gene sequences from contemporary Danish HIV-1-infected patients and sequences from the Los Alamos HIV Sequence...... Database. All Greenlandic sequences were subtype B except one sequence found to be a recombinant (probably CRF13). Sequence clusters in the phylogenetic trees indicated that there had been at least nine introductions of HIV-1 into Greenland. One cluster, supported by bootstrap values of 81, 76, and 96...

  16. HIV-Related Stigma and Discriminatory Attitudes among a Semi-Urban Population.

    Science.gov (United States)

    Lugova, Halyna; Mon, Aye Aye; Daher, Aqil Mohammad; Suleiman, Adlina

    2015-09-01

    Stigma and discriminatory attitudes (SDAs) have a negative impact on human immunodeficiency virus (HIV) prevention, testing, and treatment as well as on family and social networks. There is a lack of understanding about HIV-related SDAs among people living outside large cities. This study is aimed to determine the level of HIV-related SDAs among a semi-urban population in Malaysia and to compare the SDA results among people with different sociodemographic characteristics. A sample of 106 respondents was generated by convenience sampling during the screening campaign in Alor Gajah, Malaysia. Data collection was carried out based on a pre-tested questionnaire via face-to-face interviews. More than half of the respondents (62.3%) thought that an HIV-positive teacher should not be allowed to continue teaching at school; 81.1% were unsure or were unwilling to care for their family member with AIDS at home; 81.2% thought children with HIV/AIDS should not continue to be raised in families; and 77.3% thought they would not reveal if a family member had HIV/AIDS. Priority should be given to evidence-based interventions to reduce HIV-related SDAs. This study did not reveal any significant relationship between sociodemographic profiles and HIV-related SDAs. Therefore, further research with a larger sample size is needed to investigate the underlying causes of HIV-related SDAs.

  17. Risk of Cardiovascular Disease in an Aging HIV Population

    DEFF Research Database (Denmark)

    Martin-Iguacel, R; Llibre, J M; Friis-Moller, N

    2015-01-01

    With more effective and widespread antiretroviral treatment, the overall incidence of AIDS- or HIV-related death has decreased dramatically. Consequently, as patients are aging, cardiovascular disease (CVD) has emerged as an important cause of morbidity and mortality in the HIV population....... The incidence of CVD overall in HIV is relatively low, but it is approximately 1.5-2-fold higher than that seen in age-matched HIV-uninfected individuals. Multiple factors are believed to explain this excess in risk such as overrepresentation of traditional cardiovascular risk factors (particularly smoking...

  18. HIV populations are large and accumulate high genetic diversity in a nonlinear fashion.

    Science.gov (United States)

    Maldarelli, Frank; Kearney, Mary; Palmer, Sarah; Stephens, Robert; Mican, JoAnn; Polis, Michael A; Davey, Richard T; Kovacs, Joseph; Shao, Wei; Rock-Kress, Diane; Metcalf, Julia A; Rehm, Catherine; Greer, Sarah E; Lucey, Daniel L; Danley, Kristen; Alter, Harvey; Mellors, John W; Coffin, John M

    2013-09-01

    HIV infection is characterized by rapid and error-prone viral replication resulting in genetically diverse virus populations. The rate of accumulation of diversity and the mechanisms involved are under intense study to provide useful information to understand immune evasion and the development of drug resistance. To characterize the development of viral diversity after infection, we carried out an in-depth analysis of single genome sequences of HIV pro-pol to assess diversity and divergence and to estimate replicating population sizes in a group of treatment-naive HIV-infected individuals sampled at single (n = 22) or multiple, longitudinal (n = 11) time points. Analysis of single genome sequences revealed nonlinear accumulation of sequence diversity during the course of infection. Diversity accumulated in recently infected individuals at rates 30-fold higher than in patients with chronic infection. Accumulation of synonymous changes accounted for most of the diversity during chronic infection. Accumulation of diversity resulted in population shifts, but the rates of change were low relative to estimated replication cycle times, consistent with relatively large population sizes. Analysis of changes in allele frequencies revealed effective population sizes that are substantially higher than previous estimates of approximately 1,000 infectious particles/infected individual. Taken together, these observations indicate that HIV populations are large, diverse, and slow to change in chronic infection and that the emergence of new mutations, including drug resistance mutations, is governed by both selection forces and drift.

  19. Theorizing the complexity of HIV disclosure in vulnerable populations

    DEFF Research Database (Denmark)

    Thapa, Subash; Hannes, Karin; Buve, Anne

    2018-01-01

    BACKGROUND: HIV disclosure is an important step in delivering the right care to people. However, many people with an HIV positive status choose not to disclose. This considerably complicates the delivery of adequate health care. METHODS: We conducted a grounded theory study to develop a theoretical...... in Achham, Nepal. Data were analysed using constant-comparative method, performing three levels of open, axial, and selective coding. RESULTS: Our theoretical model illustrates how two dominant systems to control HIV, namely a community self-coping and a public health system, independently or jointly, shape...... contexts, mechanisms and outcomes for HIV disclosure. CONCLUSION: This theoretical model can be used in understanding processes of HIV disclosure in a community where HIV is concentrated in vulnerable populations and is highly stigmatized, and in determining how public health approaches would lead...

  20. 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.

  1. Screening Yield of HIV Antigen/Antibody Combination and Pooled HIV RNA Testing for Acute HIV Infection in a High-Prevalence Population.

    Science.gov (United States)

    Peters, Philip J; Westheimer, Emily; Cohen, Stephanie; Hightow-Weidman, Lisa B; Moss, Nicholas; Tsoi, Benjamin; Hall, Laura; Fann, Charles; Daskalakis, Demetre C; Beagle, Steve; Patel, Pragna; Radix, Asa; Foust, Evelyn; Kohn, Robert P; Marmorino, Jenni; Pandori, Mark; Fu, Jie; Samandari, Taraz; Gay, Cynthia L

    2016-02-16

    established and acute HIV infections) by 10.4% (95% CI, 8.8%-12.2%) and pooled HIV RNA testing increased the relative HIV diagnostic yield by 12.4% (95% CI, 10.7%-14.3%). In a high-prevalence population, HIV screening using an HIV Ag/Ab combination assay following a negative rapid test detected 82% of acute HIV infections detectable by pooled HIV RNA testing, with a positive predictive value of 59%. Further research is needed to evaluate this strategy in lower-prevalence populations and in persons using preexposure prophylaxis for HIV prevention.

  2. Differences in labour participation between people living with HIV and the general population: Results from Spain along the business cycle.

    Science.gov (United States)

    Peña Longobardo, Luz María; Oliva-Moreno, Juan

    2018-01-01

    HIV/AIDS (Human immunodeficiency virus/Acquired immune deficiency syndrome) not only has a strong impact on the health of the worldwide population but also affects the labour status of HIV-positive people. The primary aim of this paper is to compare the labour participation of people living with HIV (PlwHIV) with the labour participation of the general population along the last business cycle in Spain. The data used are from the Hospital Survey on HIV-AIDS, with a total sample size of 4,651 PlwHIV and the Labour Force Survey from 2001 to 2010, with a total sample size of 660,674 individuals as general population. Propensity Score Matching method was used to analyse the differences between the labour participation of PlwHIV and the general population. Additionally, several specific models categorised into different subgroups (gender, education, source of infection and level of defences) were also performed. We identified a convergence in labour participation across the period in the two populations considered: PlwHIV was 23% less likely to have a job than the general population during 2001-2002 and 14% less likely during 2009-2010. This convergence is mainly explained by two facts: first, the positive evolution of people infected by sex; second, the change in the PlwHIV population composition with a decreasing weight of people infected by drug use throughout the decade. Thereby, at the end of period, there was no statistical difference in the employment rate between PlwHIV infected through sex and the general population but there was strongly difference in PlwHIV infected through drugs. Inmunological status, source of infection and level of education play a relevant role among the PlwHIV population when comparing their labour participation with the general population. In spite of this positive result, the likelihood of being employed in HIV-positive people continues to be different from that of non-carriers. Our study shows that institutional features of labour

  3. No evidence of association between HIV-1 and malaria in populations with low HIV-1 prevalence.

    Directory of Open Access Journals (Sweden)

    Diego F Cuadros

    Full Text Available The geographic overlap between HIV-1 and malaria has generated much interest in their potential interactions. A variety of studies have evidenced a complex HIV-malaria interaction within individuals and populations that may have dramatic effects, but the causes and implications of this co-infection at the population level are still unclear. In a previous publication, we showed that the prevalence of malaria caused by the parasite Plasmodium falciparum is associated with HIV infection in eastern sub-Saharan Africa. To complement our knowledge of the HIV-malaria co-infection, the objective of this work was to assess the relationship between malaria and HIV prevalence in the western region of sub-Saharan Africa.Population-based cross-sectional data were obtained from the HIV/AIDS Demographic and Health Surveys conducted in Burkina Faso, Ghana, Guinea, Mali, Liberia and Cameroon, and the malaria atlas project. Using generalized linear mixed models, we assessed the relationship between HIV-1 and Plasmodium falciparum parasite rate (PfPR adjusting for important socio-economic and biological cofactors. We found no evidence that individuals living in areas with stable malaria transmission (PfPR>0.46 have higher odds of being HIV-positive than individuals who live in areas with PfPR≤0.46 in western sub-Saharan Africa (estimated odds ratio 1.14, 95% confidence interval 0.86-1.50. In contrast, the results suggested that PfPR was associated with being infected with HIV in Cameroon (estimated odds ratio 1.56, 95% confidence interval 1.23-2.00.Contrary to our previous research on eastern sub-Saharan Africa, this study did not identify an association between PfPR and infection with HIV in western sub-Saharan Africa, which suggests that malaria might not play an important role in the spread of HIV in populations where the HIV prevalence is low. Our work highlights the importance of understanding the epidemiologic effect of co-infection and the relevant

  4. Does source population size affect performance in new environments?

    Science.gov (United States)

    Yates, Matthew C; Fraser, Dylan J

    2014-01-01

    Small populations are predicted to perform poorly relative to large populations when experiencing environmental change. To explore this prediction in nature, data from reciprocal transplant, common garden, and translocation studies were compared meta-analytically. We contrasted changes in performance resulting from transplantation to new environments among individuals originating from different sized source populations from plants and salmonids. We then evaluated the effect of source population size on performance in natural common garden environments and the relationship between population size and habitat quality. In ‘home-away’ contrasts, large populations exhibited reduced performance in new environments. In common gardens, the effect of source population size on performance was inconsistent across life-history stages (LHS) and environments. When transplanted to the same set of new environments, small populations either performed equally well or better than large populations, depending on life stage. Conversely, large populations outperformed small populations within native environments, but only at later life stages. Population size was not associated with habitat quality. Several factors might explain the negative association between source population size and performance in new environments: (i) stronger local adaptation in large populations and antagonistic pleiotropy, (ii) the maintenance of genetic variation in small populations, and (iii) potential environmental differences between large and small populations. PMID:25469166

  5. Effective population size and evolutionary dynamics in outbred ...

    Indian Academy of Sciences (India)

    populations of fruit flies is not primarily driven by new mutations, but rather by changes in the frequency of ..... Drift simulation: The sex ratio, total population size and ...... Gillespie J. H. 1994a Substitution processes in molecular evolution. II.

  6. Hepatitis B Virus Vaccination in HIV-1-Infected Young Adults: A Tool to Reduce the Size of HIV-1 Reservoirs?

    Science.gov (United States)

    Bekele, Yonas; Graham, Rebecka Lantto; Soeria-Atmadja, Sandra; Nasi, Aikaterini; Zazzi, Maurizio; Vicenti, Ilaria; Naver, Lars; Nilsson, Anna; Chiodi, Francesca

    2017-01-01

    During anti-retroviral therapy (ART) HIV-1 persists in cellular reservoirs, mostly represented by CD4+ memory T cells. Several approaches are currently being undertaken to develop a cure for HIV-1 infection through elimination (or reduction) of these reservoirs. Few studies have so far been conducted to assess the possibility of reducing the size of HIV-1 reservoirs through vaccination in virologically controlled HIV-1-infected children. We recently conducted a vaccination study with a combined hepatitis A virus (HAV) and hepatitis B virus (HBV) vaccine in 22 HIV-1-infected children. We assessed the size of the virus reservoir, measured as total HIV-1 DNA copies in blood cells, pre- and postvaccination. In addition, we investigated by immunostaining whether the frequencies of CD4+ and CD8+ T cells and parameters of immune activation and proliferation on these cells were modulated by vaccination. At 1 month from the last vaccination dose, we found that 20 out of 22 children mounted a serological response to HBV; a majority of children had antibodies against HAV at baseline. The number of HIV-1 DNA copies in blood at 1 month postvaccination was reduced in comparison to baseline although this reduction was not statistically significant. A significant reduction of HIV-1 DNA copies in blood following vaccination was found in 12 children. The frequencies of CD4+ (naïve, effector memory) and CD8+ (central memory) T-cell subpopulations changed following vaccinations and a reduction in the activation and proliferation pattern of these cells was also noticed. Multivariate linear regression analysis revealed that the frequency of CD8+ effector memory T cells prior to vaccination was strongly predictive of the reduction of HIV-1 DNA copies in blood following vaccination of the 22 HIV-1-infected children. The results of this study suggest a beneficial effect of vaccination to reduce the size of virus reservoir in HIV-1-infected children receiving ART. A reduced frequency of

  7. Hepatitis B Virus Vaccination in HIV-1-Infected Young Adults: A Tool to Reduce the Size of HIV-1 Reservoirs?

    Directory of Open Access Journals (Sweden)

    Yonas Bekele

    2018-01-01

    Full Text Available During anti-retroviral therapy (ART HIV-1 persists in cellular reservoirs, mostly represented by CD4+ memory T cells. Several approaches are currently being undertaken to develop a cure for HIV-1 infection through elimination (or reduction of these reservoirs. Few studies have so far been conducted to assess the possibility of reducing the size of HIV-1 reservoirs through vaccination in virologically controlled HIV-1-infected children. We recently conducted a vaccination study with a combined hepatitis A virus (HAV and hepatitis B virus (HBV vaccine in 22 HIV-1-infected children. We assessed the size of the virus reservoir, measured as total HIV-1 DNA copies in blood cells, pre- and postvaccination. In addition, we investigated by immunostaining whether the frequencies of CD4+ and CD8+ T cells and parameters of immune activation and proliferation on these cells were modulated by vaccination. At 1 month from the last vaccination dose, we found that 20 out of 22 children mounted a serological response to HBV; a majority of children had antibodies against HAV at baseline. The number of HIV-1 DNA copies in blood at 1 month postvaccination was reduced in comparison to baseline although this reduction was not statistically significant. A significant reduction of HIV-1 DNA copies in blood following vaccination was found in 12 children. The frequencies of CD4+ (naïve, effector memory and CD8+ (central memory T-cell subpopulations changed following vaccinations and a reduction in the activation and proliferation pattern of these cells was also noticed. Multivariate linear regression analysis revealed that the frequency of CD8+ effector memory T cells prior to vaccination was strongly predictive of the reduction of HIV-1 DNA copies in blood following vaccination of the 22 HIV-1-infected children. The results of this study suggest a beneficial effect of vaccination to reduce the size of virus reservoir in HIV-1-infected children receiving ART. A reduced

  8. Hepatitis B Virus Vaccination in HIV-1-Infected Young Adults: A Tool to Reduce the Size of HIV-1 Reservoirs?

    Science.gov (United States)

    Bekele, Yonas; Graham, Rebecka Lantto; Soeria-Atmadja, Sandra; Nasi, Aikaterini; Zazzi, Maurizio; Vicenti, Ilaria; Naver, Lars; Nilsson, Anna; Chiodi, Francesca

    2018-01-01

    During anti-retroviral therapy (ART) HIV-1 persists in cellular reservoirs, mostly represented by CD4+ memory T cells. Several approaches are currently being undertaken to develop a cure for HIV-1 infection through elimination (or reduction) of these reservoirs. Few studies have so far been conducted to assess the possibility of reducing the size of HIV-1 reservoirs through vaccination in virologically controlled HIV-1-infected children. We recently conducted a vaccination study with a combined hepatitis A virus (HAV) and hepatitis B virus (HBV) vaccine in 22 HIV-1-infected children. We assessed the size of the virus reservoir, measured as total HIV-1 DNA copies in blood cells, pre- and postvaccination. In addition, we investigated by immunostaining whether the frequencies of CD4+ and CD8+ T cells and parameters of immune activation and proliferation on these cells were modulated by vaccination. At 1 month from the last vaccination dose, we found that 20 out of 22 children mounted a serological response to HBV; a majority of children had antibodies against HAV at baseline. The number of HIV-1 DNA copies in blood at 1 month postvaccination was reduced in comparison to baseline although this reduction was not statistically significant. A significant reduction of HIV-1 DNA copies in blood following vaccination was found in 12 children. The frequencies of CD4+ (naïve, effector memory) and CD8+ (central memory) T-cell subpopulations changed following vaccinations and a reduction in the activation and proliferation pattern of these cells was also noticed. Multivariate linear regression analysis revealed that the frequency of CD8+ effector memory T cells prior to vaccination was strongly predictive of the reduction of HIV-1 DNA copies in blood following vaccination of the 22 HIV-1-infected children. The results of this study suggest a beneficial effect of vaccination to reduce the size of virus reservoir in HIV-1-infected children receiving ART. A reduced frequency of

  9. Evolutionary dynamics with fluctuating population sizes and strong mutualism

    Science.gov (United States)

    Chotibut, Thiparat; Nelson, David R.

    2015-08-01

    Game theory ideas provide a useful framework for studying evolutionary dynamics in a well-mixed environment. This approach, however, typically enforces a strictly fixed overall population size, deemphasizing natural growth processes. We study a competitive Lotka-Volterra model, with number fluctuations, that accounts for natural population growth and encompasses interaction scenarios typical of evolutionary games. We show that, in an appropriate limit, the model describes standard evolutionary games with both genetic drift and overall population size fluctuations. However, there are also regimes where a varying population size can strongly influence the evolutionary dynamics. We focus on the strong mutualism scenario and demonstrate that standard evolutionary game theory fails to describe our simulation results. We then analytically and numerically determine fixation probabilities as well as mean fixation times using matched asymptotic expansions, taking into account the population size degree of freedom. These results elucidate the interplay between population dynamics and evolutionary dynamics in well-mixed systems.

  10. Evolutionary dynamics with fluctuating population sizes and strong mutualism.

    Science.gov (United States)

    Chotibut, Thiparat; Nelson, David R

    2015-08-01

    Game theory ideas provide a useful framework for studying evolutionary dynamics in a well-mixed environment. This approach, however, typically enforces a strictly fixed overall population size, deemphasizing natural growth processes. We study a competitive Lotka-Volterra model, with number fluctuations, that accounts for natural population growth and encompasses interaction scenarios typical of evolutionary games. We show that, in an appropriate limit, the model describes standard evolutionary games with both genetic drift and overall population size fluctuations. However, there are also regimes where a varying population size can strongly influence the evolutionary dynamics. We focus on the strong mutualism scenario and demonstrate that standard evolutionary game theory fails to describe our simulation results. We then analytically and numerically determine fixation probabilities as well as mean fixation times using matched asymptotic expansions, taking into account the population size degree of freedom. These results elucidate the interplay between population dynamics and evolutionary dynamics in well-mixed systems.

  11. Loss and recovery of genetic diversity in adapting populations of HIV.

    Directory of Open Access Journals (Sweden)

    Pleuni S Pennings

    2014-01-01

    Full Text Available The evolution of drug resistance in HIV occurs by the fixation of specific, well-known, drug-resistance mutations, but the underlying population genetic processes are not well understood. By analyzing within-patient longitudinal sequence data, we make four observations that shed a light on the underlying processes and allow us to infer the short-term effective population size of the viral population in a patient. Our first observation is that the evolution of drug resistance usually occurs by the fixation of one drug-resistance mutation at a time, as opposed to several changes simultaneously. Second, we find that these fixation events are accompanied by a reduction in genetic diversity in the region surrounding the fixed drug-resistance mutation, due to the hitchhiking effect. Third, we observe that the fixation of drug-resistance mutations involves both hard and soft selective sweeps. In a hard sweep, a resistance mutation arises in a single viral particle and drives all linked mutations with it when it spreads in the viral population, which dramatically reduces genetic diversity. On the other hand, in a soft sweep, a resistance mutation occurs multiple times on different genetic backgrounds, and the reduction of diversity is weak. Using the frequency of occurrence of hard and soft sweeps we estimate the effective population size of HIV to be 1.5 x 10(5 (95% confidence interval [0.8 x 10(5,4.8 x 10(5]. This number is much lower than the actual number of infected cells, but much larger than previous population size estimates based on synonymous diversity. We propose several explanations for the observed discrepancies. Finally, our fourth observation is that genetic diversity at non-synonymous sites recovers to its pre-fixation value within 18 months, whereas diversity at synonymous sites remains depressed after this time period. These results improve our understanding of HIV evolution and have potential implications for treatment strategies.

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

    NARCIS (Netherlands)

    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

  13. On population size estimators in the Poisson mixture model.

    Science.gov (United States)

    Mao, Chang Xuan; Yang, Nan; Zhong, Jinhua

    2013-09-01

    Estimating population sizes via capture-recapture experiments has enormous applications. The Poisson mixture model can be adopted for those applications with a single list in which individuals appear one or more times. We compare several nonparametric estimators, including the Chao estimator, the Zelterman estimator, two jackknife estimators and the bootstrap estimator. The target parameter of the Chao estimator is a lower bound of the population size. Those of the other four estimators are not lower bounds, and they may produce lower confidence limits for the population size with poor coverage probabilities. A simulation study is reported and two examples are investigated. © 2013, The International Biometric Society.

  14. Engagement in the HIV Care Continuum among Key Populations in Tijuana, Mexico.

    Science.gov (United States)

    Smith, Laramie R; Patterson, Thomas L; Magis-Rodriguez, Carlos; Ojeda, Victoria D; Burgos, Jose Luis; Rojas, Sarah A; Zúñiga, María Luisa; Strathdee, Steffanie A

    2016-05-01

    In Tijuana, Mexico, HIV is concentrated in sub-epidemics of key populations: persons who inject drugs (PWID), sex workers (SW), and men who have sex with men (MSM). To date, data on engagement in the HIV care continuum among these key populations, particularly in resource-constrained settings, are sparse. We pooled available epidemiological data from six studies (N = 3368) to examine HIV testing and treatment uptake in these key populations; finding an overall HIV prevalence of 5.7 %. Of the 191 identified HIV-positive persons, only 11.5 % knew their HIV-positive status and 3.7 % were on ART. Observed differences between these HIV-positive key populations suggest PWID (vs. non-PWID) were least likely to have previously tested or initiate HIV care. MSM (vs. non-MSM) were more likely to have previously tested but not more likely to know their HIV-positive status. Of persons aware of their HIV-positive status, SW (vs. non-SW) were more likely to initiate HIV care. Findings suggest engagement of key populations in HIV treatment is far below estimates observed for similarly resource-constrained generalized epidemics in sub-Saharan Africa. These data provide one of the first empirical-snapshots highlighting the extent of HIV treatment disparities in key populations.

  15. Estimating spatio-temporal dynamics of size-structured populations

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Thygesen, Uffe Høgsbro; Andersen, Ken Haste

    2014-01-01

    with simple stock dynamics, to estimate simultaneously how size distributions and spatial distributions develop in time. We demonstrate the method for a cod population sampled by trawl surveys. Particular attention is paid to correlation between size classes within each trawl haul due to clustering...... of individuals with similar size. The model estimates growth, mortality and reproduction, after which any aspect of size-structure, spatio-temporal population dynamics, as well as the sampling process can be probed. This is illustrated by two applications: 1) tracking the spatial movements of a single cohort...

  16. Determination of the optimal sample size for a clinical trial accounting for the population size.

    Science.gov (United States)

    Stallard, Nigel; Miller, Frank; Day, Simon; Hee, Siew Wan; Madan, Jason; Zohar, Sarah; Posch, Martin

    2017-07-01

    The problem of choosing a sample size for a clinical trial is a very common one. In some settings, such as rare diseases or other small populations, the large sample sizes usually associated with the standard frequentist approach may be infeasible, suggesting that the sample size chosen should reflect the size of the population under consideration. Incorporation of the population size is possible in a decision-theoretic approach either explicitly by assuming that the population size is fixed and known, or implicitly through geometric discounting of the gain from future patients reflecting the expected population size. This paper develops such approaches. Building on previous work, an asymptotic expression is derived for the sample size for single and two-arm clinical trials in the general case of a clinical trial with a primary endpoint with a distribution of one parameter exponential family form that optimizes a utility function that quantifies the cost and gain per patient as a continuous function of this parameter. It is shown that as the size of the population, N, or expected size, N∗ in the case of geometric discounting, becomes large, the optimal trial size is O(N1/2) or O(N∗1/2). The sample size obtained from the asymptotic expression is also compared with the exact optimal sample size in examples with responses with Bernoulli and Poisson distributions, showing that the asymptotic approximations can also be reasonable in relatively small sample sizes. © 2016 The Author. Biometrical Journal published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Risk of cancer among HIV-infected individuals compared to the background population

    DEFF Research Database (Denmark)

    Helleberg, Marie; Gerstoft, Jan; Afzal, Shoaib

    2014-01-01

    BACKGROUND: The relative impact of immune deficiency and lifestyle-related factors on risk of cancer in the HIV-infected population is controversial. We aimed to estimate the population-attributable fractions (PAFs) associated with smoking, being HIV-infected and with immune deficiency. METHODS...... of cancer associated with smoking and with being HIV-infected were 27 and 49%, respectively. For cancers not strongly related to smoking or viral infections, the PAFs associated with being HIV-infected and with immune deficiency were 0%. CONCLUSION: The risk of cancer is increased in HIV patients compared......: In a Danish, nationwide, population-based cohort study (1995-2011), incidences of cancer were compared between an HIV-infected cohort and a population-based matched cohort in analyses stratified on cancer category, smoking status and for HIV patients: low CD4 cell count. RESULTS: We included 3503 HIV patients...

  18. Individual and Population Level Impact of Key HIV Risk Factors on HIV Incidence Rates in Durban, South Africa.

    Directory of Open Access Journals (Sweden)

    Gita Ramjee

    Full Text Available We aimed to estimate the individual and joint impact of age, marital status and diagnosis with sexually transmitted infections (STIs on HIV acquisition among young women at a population level in Durban, KwaZulu-Natal, South Africa. A total of 3,978 HIV seronegative women were recruited for four biomedical intervention trials from 2002-2009. Point and interval estimates of partial population attributable risk (PAR were used to quantify the proportion of HIV seroconversions which can be prevented if a combination of risk factors is eliminated from a target population. More than 70% of the observed HIV acquisitions were collectively attributed to the three risk factors: younger age (<25 years old, unmarried and not cohabiting with a stable/regular partner and diagnosis with STIs. Addressing these risks requires targeted structural, behavioural, biomedical and cultural interventions in order to impact on unacceptably high HIV incidence rates among young women and the population as a whole.

  19. Epidemiological and Immunological Characteristics at the Time of HIV Diagnosis for HIV/AIDS Cohort Registrants Representative of HIV-Infected Populations in Korea

    OpenAIRE

    Lee, Jin-Hee; Kim, Seung Hyun; Wang, Jin-Sook; Sung, Kyoung Mi; Kim, Sung Soon; Kee, Mee-Kyung

    2012-01-01

    Objectives The Korea HIV/AIDS cohort was constructed with 18 hospitals that care for HIV-infected individuals in 2006. We compared the epidemiological and immunological characteristics of the cohort registrants with those of the HIVinfected population at the time of HIV diagnosis. Methods This study was conducted on 5717 people living with HIV/AIDS from 1985 to 2009, of which 789 individuals registered with the Korea HIV/AIDS cohort study. Individuals who had data from initial CD4+ T-cell cou...

  20. Population profiling in China by gender and age: implication for HIV incidences.

    Science.gov (United States)

    Pan, Yuanyi; Wu, Jianhong

    2009-11-18

    With the world's largest population, HIV spread in China has been closely watched and widely studied by its government and the international community. One important factor that might contribute to the epidemic is China's numerous surplus of men, due to its imbalanced sex ratio in newborns. However, the sex ratio in the human population is often assumed to be 1:1 in most studies of sexually transmitted diseases (STDs). Here, a mathematical model is proposed to estimate the population size in each gender and within different stages of reproduction and sexual activities. This population profiling by age and gender will assist in more precise prediction of HIV incidences. The total population is divided into 6 subgroups by gender and age. A deterministic compartmental model is developed to describe birth, death, age and the interactions among different subgroups, with a focus on the preference for newborn boys and its impact for the sex ratios. Data from 2003 to 2007 is used to estimate model parameters, and simulations predict short-term and long-term population profiles. The population of China will go to a descending track around 2030. Despite the possible underestimated number of newborns in the last couple of years, model-based simulations show that there will be about 28 million male individuals in 2055 without female partners during their sexually active stages. The birth rate in China must be increased to keep the population viable. But increasing the birth rate without balancing the sex ratio in newborns is problematic, as this will generate a large number of surplus males. Besides other social, economic and psychological issues, the impact of this surplus of males on STD incidences, including HIV infections, must be dealt with as early as possible.

  1. Population profiling in China by gender and age: implication for HIV incidences

    Science.gov (United States)

    2009-01-01

    Background With the world's largest population, HIV spread in China has been closely watched and widely studied by its government and the international community. One important factor that might contribute to the epidemic is China's numerous surplus of men, due to its imbalanced sex ratio in newborns. However, the sex ratio in the human population is often assumed to be 1:1 in most studies of sexually transmitted diseases (STDs). Here, a mathematical model is proposed to estimate the population size in each gender and within different stages of reproduction and sexual activities. This population profiling by age and gender will assist in more precise prediction of HIV incidences. Method The total population is divided into 6 subgroups by gender and age. A deterministic compartmental model is developed to describe birth, death, age and the interactions among different subgroups, with a focus on the preference for newborn boys and its impact for the sex ratios. Data from 2003 to 2007 is used to estimate model parameters, and simulations predict short-term and long-term population profiles. Results The population of China will go to a descending track around 2030. Despite the possible underestimated number of newborns in the last couple of years, model-based simulations show that there will be about 28 million male individuals in 2055 without female partners during their sexually active stages. Conclusion The birth rate in China must be increased to keep the population viable. But increasing the birth rate without balancing the sex ratio in newborns is problematic, as this will generate a large number of surplus males. Besides other social, economic and psychological issues, the impact of this surplus of males on STD incidences, including HIV infections, must be dealt with as early as possible. PMID:19922693

  2. Sample size methods for estimating HIV incidence from cross-sectional surveys.

    Science.gov (United States)

    Konikoff, Jacob; Brookmeyer, Ron

    2015-12-01

    Understanding HIV incidence, the rate at which new infections occur in populations, is critical for tracking and surveillance of the epidemic. In this article, we derive methods for determining sample sizes for cross-sectional surveys to estimate incidence with sufficient precision. We further show how to specify sample sizes for two successive cross-sectional surveys to detect changes in incidence with adequate power. In these surveys biomarkers such as CD4 cell count, viral load, and recently developed serological assays are used to determine which individuals are in an early disease stage of infection. The total number of individuals in this stage, divided by the number of people who are uninfected, is used to approximate the incidence rate. Our methods account for uncertainty in the durations of time spent in the biomarker defined early disease stage. We find that failure to account for this uncertainty when designing surveys can lead to imprecise estimates of incidence and underpowered studies. We evaluated our sample size methods in simulations and found that they performed well in a variety of underlying epidemics. Code for implementing our methods in R is available with this article at the Biometrics website on Wiley Online Library. © 2015, The International Biometric Society.

  3. Public goods games in populations with fluctuating size.

    Science.gov (United States)

    McAvoy, Alex; Fraiman, Nicolas; Hauert, Christoph; Wakeley, John; Nowak, Martin A

    2018-05-01

    Many mathematical frameworks of evolutionary game dynamics assume that the total population size is constant and that selection affects only the relative frequency of strategies. Here, we consider evolutionary game dynamics in an extended Wright-Fisher process with variable population size. In such a scenario, it is possible that the entire population becomes extinct. Survival of the population may depend on which strategy prevails in the game dynamics. Studying cooperative dilemmas, it is a natural feature of such a model that cooperators enable survival, while defectors drive extinction. Although defectors are favored for any mixed population, random drift could lead to their elimination and the resulting pure-cooperator population could survive. On the other hand, if the defectors remain, then the population will quickly go extinct because the frequency of cooperators steadily declines and defectors alone cannot survive. In a mutation-selection model, we find that (i) a steady supply of cooperators can enable long-term population survival, provided selection is sufficiently strong, and (ii) selection can increase the abundance of cooperators but reduce their relative frequency. Thus, evolutionary game dynamics in populations with variable size generate a multifaceted notion of what constitutes a trait's long-term success. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Reliability of different mark-recapture methods for population size estimation tested against reference population sizes constructed from field data.

    Directory of Open Access Journals (Sweden)

    Annegret Grimm

    Full Text Available Reliable estimates of population size are fundamental in many ecological studies and biodiversity conservation. Selecting appropriate methods to estimate abundance is often very difficult, especially if data are scarce. Most studies concerning the reliability of different estimators used simulation data based on assumptions about capture variability that do not necessarily reflect conditions in natural populations. Here, we used data from an intensively studied closed population of the arboreal gecko Gehyra variegata to construct reference population sizes for assessing twelve different population size estimators in terms of bias, precision, accuracy, and their 95%-confidence intervals. Two of the reference populations reflect natural biological entities, whereas the other reference populations reflect artificial subsets of the population. Since individual heterogeneity was assumed, we tested modifications of the Lincoln-Petersen estimator, a set of models in programs MARK and CARE-2, and a truncated geometric distribution. Ranking of methods was similar across criteria. Models accounting for individual heterogeneity performed best in all assessment criteria. For populations from heterogeneous habitats without obvious covariates explaining individual heterogeneity, we recommend using the moment estimator or the interpolated jackknife estimator (both implemented in CAPTURE/MARK. If data for capture frequencies are substantial, we recommend the sample coverage or the estimating equation (both models implemented in CARE-2. Depending on the distribution of catchabilities, our proposed multiple Lincoln-Petersen and a truncated geometric distribution obtained comparably good results. The former usually resulted in a minimum population size and the latter can be recommended when there is a long tail of low capture probabilities. Models with covariates and mixture models performed poorly. Our approach identified suitable methods and extended options to

  5. Estimation of effective population size in continuously distributed populations: There goes the neighborhood

    Science.gov (United States)

    M. C. Neel; K. McKelvey; N. Ryman; M. W. Lloyd; R. Short Bull; F. W. Allendorf; M. K. Schwartz; R. S. Waples

    2013-01-01

    Use of genetic methods to estimate effective population size (Ne) is rapidly increasing, but all approaches make simplifying assumptions unlikely to be met in real populations. In particular, all assume a single, unstructured population, and none has been evaluated for use with continuously distributed species. We simulated continuous populations with local mating...

  6. The critical domain size of stochastic population models.

    Science.gov (United States)

    Reimer, Jody R; Bonsall, Michael B; Maini, Philip K

    2017-02-01

    Identifying the critical domain size necessary for a population to persist is an important question in ecology. Both demographic and environmental stochasticity impact a population's ability to persist. Here we explore ways of including this variability. We study populations with distinct dispersal and sedentary stages, which have traditionally been modelled using a deterministic integrodifference equation (IDE) framework. Individual-based models (IBMs) are the most intuitive stochastic analogues to IDEs but yield few analytic insights. We explore two alternate approaches; one is a scaling up to the population level using the Central Limit Theorem, and the other a variation on both Galton-Watson branching processes and branching processes in random environments. These branching process models closely approximate the IBM and yield insight into the factors determining the critical domain size for a given population subject to stochasticity.

  7. Sex inequalities in HIV-related practices in the Brazilian population aged 15 to 64 years old, 2008

    Directory of Open Access Journals (Sweden)

    Ana Roberta Pati Pascom

    2011-01-01

    Full Text Available The objective of this study is to analyze gender differences in HIV-related practices in the Brazilian population. A national survey was carried out in 2008 with a sample size of 8,000 individuals aged 15-64 years old. The sampling was stratified by macro geographical region and urban/rural areas. Logistic regression models were used to investigate the main predictors of consistent condom use. The results showed that women have less sexy, start sexual life later than men, have fewer casual sexual partners, but use condom less frequently than men. On the other hand, the coverage of HIV testing is significantly greater among women. Significant differences by gender were seen in all HIV-related risky practices. The greater vulnerability was always associated with women, with exception of HIV testing. The low proportion of condom use in infidelity situations was a problem for box sexes and deserves special consideration when developing prevention strategies.

  8. HIV/AIDS Interventions in an Aging U.S. Population

    Science.gov (United States)

    Jacobson, Stephanie A.

    2011-01-01

    According to the Centers for Disease Control and Prevention (CDC), 25 percent of people living with HIV in the United States in 2006 were age 50 and older. HIV prevention for people over 50 is an important health concern, especially as the U.S. population grows older. Scholarly research has identified the need for HIV/AIDS interventions in the…

  9. HIV and STI epidemiology in high-risk populations in the Netherlands

    NARCIS (Netherlands)

    van Veen, M.G.

    2010-01-01

    Studies described in this thesis underline the need to enhance HIV testing in the Netherlands, since a large proportion of HIV-infected persons remain unaware of their infection. In particular HIV testing among ethnic minority populations and commercial sex workers should be scaled up, especially in

  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. Population estimates of extended family structure and size.

    Science.gov (United States)

    Garceau, Anne; Wideroff, Louise; McNeel, Timothy; Dunn, Marsha; Graubard, Barry I

    2008-01-01

    Population-based estimates of biological family size can be useful for planning genetic studies, assessing how distributions of relatives affect disease associations with family history and estimating prevalence of potential family support. Mean family size per person is estimated from a population-based telephone survey (n = 1,019). After multivariate adjustment for demographic variables, older and non-White respondents reported greater mean numbers of total, first- and second-degree relatives. Females reported more total and first-degree relatives, while less educated respondents reported more second-degree relatives. Demographic differences in family size have implications for genetic research. Therefore, periodic collection of family structure data in representative populations would be useful. Copyright 2008 S. Karger AG, Basel.

  12. The Relationship Between Population Size and Contracting Out Public Services

    DEFF Research Database (Denmark)

    Foged, Søren Kjær

    2015-01-01

    /contracting out relationship. Results show that the relationship differs across policy sectors: It is negative for services with high fixed costs, presumably due to scale economies, and is positive for services that are difficult to measure, probably due to more administrative and technical capacity in larger......What is the causal relationship between population size and the contracting out of public service delivery in local governments? The size of the population of a given municipality has long been thought to be an important driver of contracting out public service delivery, which theoretically...... streamlines public service production and saves taxpayers’ money. This article makes use of the 2007 Danish local government structural reform—when 239 municipalities were merged into 66 new entities while 29 municipalities remained untouched—as a quasi-experiment to explore the population size...

  13. Competition in size-structured populations: mechanisms inducing cohort formation and population cycles

    NARCIS (Netherlands)

    de Roos, A.M.; Persson, L.

    2003-01-01

    In this paper we investigate the consequences of size-dependent competition among the individuals of a consumer population by analyzing the dynamic properties of a physiologically structured population model. Only 2 size-classes of individuals are distinguished: juveniles and adults. Juveniles and

  14. Potential health impacts of heavy metals on HIV-infected population in USA.

    Directory of Open Access Journals (Sweden)

    Xiaohui Xu

    Full Text Available PURPOSE: Noninfectious comorbidities such as cardiovascular diseases have become increasingly prevalent and occur earlier in life in persons with HIV infection. Despite the emerging body of literature linking environmental exposures to chronic disease outcomes in the general population, the impacts of environmental exposures have received little attention in HIV-infected population. The aim of this study is to investigate whether individuals living with HIV have elevated prevalence of heavy metals compared to non-HIV infected individuals in United States. METHODS: We used the National Health and Nutrition Examination Survey (NHANES 2003-2010 to compare exposures to heavy metals including cadmium, lead, and total mercury in HIV infected and non-HIV infected subjects. RESULTS: In this cross-sectional study, we found that HIV-infected individuals had higher concentrations of all heavy metals than the non-HIV infected group. In a multivariate linear regression model, HIV status was significantly associated with increased blood cadmium (p=0.03 after adjusting for age, sex, race, education, poverty income ratio, and smoking. However, HIV status was not statistically associated with lead or mercury levels after adjusting for the same covariates. CONCLUSIONS: Our findings suggest that HIV-infected patients might be significantly more exposed to cadmium compared to non-HIV infected individuals which could contribute to higher prevalence of chronic diseases among HIV-infected subjects. Further research is warranted to identify sources of exposure and to understand more about specific health outcomes.

  15. A robust measure of HIV-1 population turnover within chronically infected individuals.

    Science.gov (United States)

    Achaz, G; Palmer, S; Kearney, M; Maldarelli, F; Mellors, J W; Coffin, J M; Wakeley, J

    2004-10-01

    A simple nonparameteric test for population structure was applied to temporally spaced samples of HIV-1 sequences from the gag-pol region within two chronically infected individuals. The results show that temporal structure can be detected for samples separated by about 22 months or more. The performance of the method, which was originally proposed to detect geographic structure, was tested for temporally spaced samples using neutral coalescent simulations. Simulations showed that the method is robust to variation in samples sizes and mutation rates, to the presence/absence of recombination, and that the power to detect temporal structure is high. By comparing levels of temporal structure in simulations to the levels observed in real data, we estimate the effective intra-individual population size of HIV-1 to be between 10(3) and 10(4) viruses, which is in agreement with some previous estimates. Using this estimate and a simple measure of sequence diversity, we estimate an effective neutral mutation rate of about 5 x 10(-6) per site per generation in the gag-pol region. The definition and interpretation of estimates of such "effective" population parameters are discussed.

  16. Generation time and effective population size in Polar Eskimos

    Science.gov (United States)

    Matsumura, Shuichi; Forster, Peter

    2008-01-01

    North Greenland Polar Eskimos are the only hunter–gatherer population, to our knowledge, who can offer precise genealogical records spanning several generations. This is the first report from Eskimos on two key parameters in population genetics, namely, generation time (T) and effective population size (Ne). The average mother–daughter and father–son intervals were 27 and 32 years, respectively, roughly similar to the previously published generation times obtained from recent agricultural societies across the world. To gain an insight for the generation time in our distant ancestors, we calculated maternal generation time for two wild chimpanzee populations. We also provide the first comparison among three distinct approaches (genealogy, variance and life table methods) for calculating Ne, which resulted in slightly differing values for the Eskimos. The ratio of the effective to the census population size is estimated as 0.6–0.7 for autosomal and X-chromosomal DNA, 0.7–0.9 for mitochondrial DNA and 0.5 for Y-chromosomal DNA. A simulation of alleles along the genealogy suggested that Y-chromosomal DNA may drift a little faster than mitochondrial DNA in this population, in contrast to agricultural Icelanders. Our values will be useful not only in prehistoric population inference but also in understanding the shaping of our genome today. PMID:18364314

  17. Adaptive evolution and effective population size in wild house mice

    Czech Academy of Sciences Publication Activity Database

    Phifer-Rixey, M.; Bonhomme, F.; Boursot, P.; Churchill, G. A.; Piálek, Jaroslav; Tucker, P.; Nachman, M.

    2012-01-01

    Roč. 29, č. 10 (2012), s. 2949-2955 ISSN 0737-4038 R&D Projects: GA ČR GA206/08/0640 Institutional support: RVO:68081766 Keywords : substitution * adaptation * evolution * effective population size * house mouse Subject RIV: EG - Zoology Impact factor: 10.353, year: 2012

  18. Effect of small mapping population sizes on reliability of quantitative ...

    African Journals Online (AJOL)

    A limitation of quantitative trait loci (QTL) mapping is that accuracy of determining QTL position and effects are largely determined by population size. Despite the importance of this concept, known as the "Beavis effect there has generally been a lack of understanding by molecular geneticists and breeders. One possible ...

  19. Estimating population size of Saddle-billed Storks Ephippiorhynchus ...

    African Journals Online (AJOL)

    The aim of this study was to estimate the population size within associated confidence limits using a modified mark–recapture field method. The vehicle survey, conducted shortly after rainfall in the area, did not produce results with known precision under these conditions. A repeat of this census in spring, after the peak ...

  20. Short communication Effective population size and inbreeding rate ...

    African Journals Online (AJOL)

    201010100

    2013-05-30

    May 30, 2013 ... Understanding and estimating effective population size for practical application in marine species management. Conservation Biology 25 (3), 438-449. Mapiye, C., Chimonyo, M., Muchenje, V., Dzama, K., Marufu, M.C. & Raats, J.G., 2007. Potential for value-addition of Nguni cattle products in the communal ...

  1. Effect of population size on prospect of species survival

    Czech Academy of Sciences Publication Activity Database

    Münzbergová, Zuzana

    2006-01-01

    Roč. 41, - (2006), s. 137-150 ISSN 1211-9520 R&D Projects: GA AV ČR KJB6111303 Institutional research plan: CEZ:AV0Z60050516 Keywords : population * size * survival Subject RIV: EF - Botanics Impact factor: 1.196, year: 2006

  2. Estimating the size of the homeless population in Budapest, Hungary

    NARCIS (Netherlands)

    David, B; Snijders, TAB

    In this study we try to estimate the size of the homeless population in Budapest by using two - non-standard - sampling methods: snowball sampling and capture-recapture method. Using two methods and three different data sets we are able to compare the methods as well as the results, and we also

  3. Sampling strategies for estimating brook trout effective population size

    Science.gov (United States)

    Andrew R. Whiteley; Jason A. Coombs; Mark Hudy; Zachary Robinson; Keith H. Nislow; Benjamin H. Letcher

    2012-01-01

    The influence of sampling strategy on estimates of effective population size (Ne) from single-sample genetic methods has not been rigorously examined, though these methods are increasingly used. For headwater salmonids, spatially close kin association among age-0 individuals suggests that sampling strategy (number of individuals and location from...

  4. Short communication: Effective population size and inbreeding rate ...

    African Journals Online (AJOL)

    Short communication: Effective population size and inbreeding rate of indigenous Nguni cattle under in situ conservation in the low-input communal production ... as not at risk of extinction, while the individual enterprises were classified as being endangered-maintained without the exchange of germ plasm among them.

  5. Family size and effective population size in a hatchery stock of coho salmon (Oncorhynchus kisutch)

    Science.gov (United States)

    Simon, R.C.; McIntyre, J.D.; Hemmingsen, A.R.

    1986-01-01

    Means and variances of family size measured in five year-classes of wire-tagged coho salmon (Oncorhynchus kisutch) were linearly related. Population effective size was calculated by using estimated means and variances of family size in a 25-yr data set. Although numbers of age 3 adults returning to the hatchery appeared to be large enough to avoid inbreeding problems (the 25-yr mean exceeded 4500), the numbers actually contributing to the hatchery production may be too low. Several strategies are proposed to correct the problem perceived. Argument is given to support the contention that the problem of effective size is fairly general and is not confined to the present study population.

  6. China's floating population and the potential for HIV transmission: a social-behavioural perspective.

    Science.gov (United States)

    Anderson, A F; Qingsi, Z; Hua, X; Jianfeng, B

    2003-04-01

    Historical, geo-economic and behavioural perspectives are used in an exploratory analysis of China's migrant or 'floating' population as a factor in the spread of HIV on the mainland. Participants in the interview format survey (N = 506) included in-transit individuals in Beijing, and peddlers, restaurant workers, and employment seekers in Shanghai. When viewed in light of various social dynamics, the convenience survey data suggest that elements within this migrant population, as well as their rurally located partners and spouses, may be at increased risk of acquiring the virus. Given the sheer size and broad movement of this population, it is contended that it may well be a 'tipping point' factor in AIDS prevention and control in China.

  7. Influences of population size and density on birthplace effects.

    Science.gov (United States)

    Hancock, David J; Coutinho, Patrícia; Côté, Jean; Mesquita, Isabel

    2018-01-01

    Contextual influences on talent development (e.g., birthplace effects) have become a topic of interest for sport scientists. Birthplace effects occur when being born in a certain city size leads to participation or performance advantages, typically for those born in smaller or mid-sized cities. The purpose of this study was to investigate birthplace effects in Portuguese volleyball players by analysing city size, as well as population density - an important but infrequently used variable. Participants included 4062 volleyball players (M age  = 33), 53.2% of whom were men. Using Portuguese national census data from 1981, we compared participants (within each sex) across five population categories. In addition, we used ANOVAs to study expertise and population density. Results indicated that men and women athletes born in districts of 200,000-399,999 were 2.4 times more likely to attain elite volleyball status, while all other districts decreased the odds of expert development. For men, being born in high-density areas resulted in less chance of achieving expertise, whereas there were no differences for women. The results suggest that athletes' infrastructure and social structure play an important role in talent development, and that these structures are influenced by total population and population density, respectively.

  8. Regional differences, socio-demographics, and hidden population of HIV/AIDS in India.

    Science.gov (United States)

    Kumar, Rajeev; Suar, Damodar; Singh, Sanjay Kumar

    2017-02-01

    This study examines the prevalence of HIV/AIDS in different regions of India, their socio-demographic indicators, and the presence of hidden population infected with HIV. Secondary data analyzed were obtained from national and international agencies. Considering the prevalence of HIV/AIDS in India, the low-prevalence regions in the last decade have shown a steady increase in recent years. Productive age, urbanization, male gender, lower level of education, minority religions, low income, and mobile occupations are associated with HIV pandemic. The hidden population vulnerable to HIV/AIDS are: street children, homeless population, and refugees. These observations can help map the high-risk behavior groups and formulate targeted strategies to curb the HIV menace.

  9. Structured population dynamics: continuous size and discontinuous stage structures.

    Science.gov (United States)

    Buffoni, Giuseppe; Pasquali, Sara

    2007-04-01

    A nonlinear stochastic model for the dynamics of a population with either a continuous size structure or a discontinuous stage structure is formulated in the Eulerian formalism. It takes into account dispersion effects due to stochastic variability of the development process of the individuals. The discrete equations of the numerical approximation are derived, and an analysis of the existence and stability of the equilibrium states is performed. An application to a copepod population is illustrated; numerical results of Eulerian and Lagrangian models are compared.

  10. Knowledge and Concern about STIs/HIV and Sociodemographic Variables Associated with Getting Tested for HIV Among the General Population in Spain.

    Science.gov (United States)

    Teva, Inmaculada; de Araújo, Ludgleydson Fernandes; de la Paz Bermúdez, María

    2018-07-04

    HIV testing is important in terms of prevention and treatment. However, HIV testing rates in the Spanish general population remains low. Therefore, HIV testing promotion constitutes a key issue. A high level of knowledge about HIV/AIDS is associated with having been tested for HIV. The general aim of this study was to determine the prevalence of people who had ever been tested for HIV in Spain. The sample consisted of 1,106 participants from the general population - 60.0% females and 40.0% males - aged between 17 and 55 years old. The assessment instruments were a questionnaire on sociodemographic data and HIV testing, a scale of knowledge about STIs and HIV/AIDS, and a scale of concern about STIs/HIV. Results showed that greater knowledge about STIs and HIV was associated with a greater likelihood of being tested for HIV (OR = .77; 95.0% CI = .73-.82; p concern about HIV/AIDS decreased the likelihood of not having been tested for HIV (OR = .87; 95.0% CI = .83-.92; p concern about STIs was, the lower their likelihood of not having been tested for HIV was (OR = .87; 95.0% CI = .83-.91; p < .05). It is necessary to promote HIV testing in the general population as well as to consider their socio-demographic and psychological characteristics.

  11. Critical mutation rate has an exponential dependence on population size in haploid and diploid populations.

    Directory of Open Access Journals (Sweden)

    Elizabeth Aston

    Full Text Available Understanding the effect of population size on the key parameters of evolution is particularly important for populations nearing extinction. There are evolutionary pressures to evolve sequences that are both fit and robust. At high mutation rates, individuals with greater mutational robustness can outcompete those with higher fitness. This is survival-of-the-flattest, and has been observed in digital organisms, theoretically, in simulated RNA evolution, and in RNA viruses. We introduce an algorithmic method capable of determining the relationship between population size, the critical mutation rate at which individuals with greater robustness to mutation are favoured over individuals with greater fitness, and the error threshold. Verification for this method is provided against analytical models for the error threshold. We show that the critical mutation rate for increasing haploid population sizes can be approximated by an exponential function, with much lower mutation rates tolerated by small populations. This is in contrast to previous studies which identified that critical mutation rate was independent of population size. The algorithm is extended to diploid populations in a system modelled on the biological process of meiosis. The results confirm that the relationship remains exponential, but show that both the critical mutation rate and error threshold are lower for diploids, rather than higher as might have been expected. Analyzing the transition from critical mutation rate to error threshold provides an improved definition of critical mutation rate. Natural populations with their numbers in decline can be expected to lose genetic material in line with the exponential model, accelerating and potentially irreversibly advancing their decline, and this could potentially affect extinction, recovery and population management strategy. The effect of population size is particularly strong in small populations with 100 individuals or less; the

  12. Matrimonial distance, inbreeding coefficient and population size: Dhangar data.

    Science.gov (United States)

    Majumder, P P; Malhotra, K C

    1979-01-01

    Data on the distance between the birthplaces of spouses (matrimonial distance) were collected from 2,260 married individuals belonging to 21 endogamous castes of the Dhangar (shepherd) cast-cluster of Maharashtra, India. The general form of the distribution of matrimonial distances is one which is extremely positively skewed and leptokurtic. The percentage of intra-village marriages generally decreases from the southern areas of Maharashtra to the northern areas of the state, as does the inbreeding coefficient. This situation is in conformity with the socio-cultural norms regulating matrimonial choice in south and north India. An attempt has been made to relate the degree of inbreeding to the mean matrimonial distance and population size. The mean matrimonial distance is more useful in predicting the degree of inbreeding than population size.

  13. 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

  14. 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

  15. Knowledge, attitudes and practices on HIV/AIDS and prevalence of HIV in the general population of Sucre, Bolivia.

    Science.gov (United States)

    Terán Calderón, Carolina; Gorena Urizar, Dorian; González Blázquez, Cristina; Alejos Ferreras, Belén; Ramírez Rubio, Oriana; Bolumar Montrull, Francisco; Ortiz Rivera, Marta; del Amo Valero, Julia

    2015-01-01

    To analyse knowledge, attitudes and sexual practices on HIV/AIDS, and estimate HIV prevalence among residents of Sucre (Bolivia). Population-based survey of residents aged 15-49 randomly selected during 2008/2009. Blood samples were collected on Whatman-filter paper and tested with enzyme-linked immunosorbent assay. Knowledge on HIV/AIDS, sexual risk practices and discriminatory attitudes against people living with HIV/AIDS (PLWHA) were modelled with multiple logistic regression. Of 1499 subjects, 59% were women. All subjects were HIV-negative. Inadequate knowledge of HIV/AIDS transmission and prevention was observed in 67% and risk factors varied by gender (interaction p-value<0.05). Discriminatory attitudes were displayed by 85% subjects; associated factors were: rural residence, low educational level and low income. Unsafe sex was reported by 10%; risk factors varied by residence area (interaction p-value<0.05). In urban areas, risk factors were male sex, younger age and being in common-law union. Prevalence of HIV infection is very low and unsafe sex is relatively uncommon. Inadequate knowledge on HIV/AIDS and discriminatory attitudes towards PLWHA are extremely high and are associated to gender, ethnic and economic inequalities. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.

  16. Weaker HLA Footprints on HIV in the Unique and Highly Genetically Admixed Host Population of Mexico.

    Science.gov (United States)

    Soto-Nava, Maribel; Avila-Ríos, Santiago; Valenzuela-Ponce, Humberto; García-Morales, Claudia; Carlson, Jonathan M; Tapia-Trejo, Daniela; Garrido-Rodriguez, Daniela; Alva-Hernández, Selma N; García-Tellez, Thalía A; Murakami-Ogasawara, Akio; Mallal, Simon A; John, Mina; Brockman, Mark A; Brumme, Chanson J; Brumme, Zabrina L; Reyes-Teran, Gustavo

    2018-01-15

    HIV circumvents HLA class I-restricted CD8 + T-cell responses through selection of escape mutations that leave characteristic mutational "footprints," also known as HLA-associated polymorphisms (HAPs), on HIV sequences at the population level. While many HLA footprints are universal across HIV subtypes and human populations, others can be region specific as a result of the unique immunogenetic background of each host population. Using a published probabilistic phylogenetically informed model, we compared HAPs in HIV Gag and Pol (PR-RT) in 1,612 subtype B-infected, antiretroviral treatment-naive individuals from Mexico and 1,641 individuals from Canada/United States. A total of 252 HLA class I allele subtypes were represented, including 140 observed in both cohorts, 67 unique to Mexico, and 45 unique to Canada/United States. At the predefined statistical threshold of a q value of HIV in Mexico were not only fewer but also, on average, significantly weaker than those in Canada/United States, although some exceptions were noted. Moreover, exploratory analyses suggested that the weaker HLA footprint on HIV in Mexico may be due, at least in part, to weaker and/or less reproducible HLA-mediated immune pressures on HIV in this population. The implications of these differences for natural and vaccine-induced anti-HIV immunity merit further investigation. IMPORTANCE HLA footprints on HIV identify viral regions under intense and consistent pressure by HLA-restricted immune responses and the common mutational pathways that HIV uses to evade them. In particular, HLA footprints can identify novel immunogenic regions and/or epitopes targeted by understudied HLA alleles; moreover, comparative analyses across immunogenetically distinct populations can illuminate the extent to which HIV immunogenic regions and escape pathways are shared versus population-specific pathways, information which can in turn inform the design of universal or geographically tailored HIV vaccines. We

  17. Population size of Aegla paulensis (Decapoda: Anomura: Aeglidae

    Directory of Open Access Journals (Sweden)

    Felipe P.A Cohen

    2013-09-01

    Full Text Available We used the Schumacher-Eschmeyer method for closed populations to estimate and compare the population size of adults of Aeglapaulensis, from Jaraguá State Park (São Paulo, Brazil, in two periods of the year with contrasting climatic conditions (late winter and late summer. The calculated density of adult individuals was considerably higher in the summer (11.5 ind m-2 than in the winter (6.7 ind m-2. This density difference of adult individuals was attributed to variation in the population structure of coexisting cohorts of adults at each sampling season of the year, due to dissimilarities in the cumulative abundance of recruits that effectively become adults after puberty molt, and difference in longevity between sexes.

  18. 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.

  19. Genotypic Resistance Tests Sequences Reveal the Role of Marginalized Populations in HIV-1 Transmission in Switzerland.

    Science.gov (United States)

    Shilaih, Mohaned; Marzel, Alex; Yang, Wan Lin; Scherrer, Alexandra U; Schüpbach, Jörg; Böni, Jürg; Yerly, Sabine; Hirsch, Hans H; Aubert, Vincent; Cavassini, Matthias; Klimkait, Thomas; Vernazza, Pietro L; Bernasconi, Enos; Furrer, Hansjakob; Günthard, Huldrych F; Kouyos, Roger

    2016-06-14

    Targeting hard-to-reach/marginalized populations is essential for preventing HIV-transmission. A unique opportunity to identify such populations in Switzerland is provided by a database of all genotypic-resistance-tests from Switzerland, including both sequences from the Swiss HIV Cohort Study (SHCS) and non-cohort sequences. A phylogenetic tree was built using 11,127 SHCS and 2,875 Swiss non-SHCS sequences. Demographics were imputed for non-SHCS patients using a phylogenetic proximity approach. Factors associated with non-cohort outbreaks were determined using logistic regression. Non-B subtype (univariable odds-ratio (OR): 1.9; 95% confidence interval (CI): 1.8-2.1), female gender (OR: 1.6; 95% CI: 1.4-1.7), black ethnicity (OR: 1.9; 95% CI: 1.7-2.1) and heterosexual transmission group (OR:1.8; 95% CI: 1.6-2.0), were all associated with underrepresentation in the SHCS. We found 344 purely non-SHCS transmission clusters, however, these outbreaks were small (median 2, maximum 7 patients) with a strong overlap with the SHCS'. 65% of non-SHCS sequences were part of clusters composed of >= 50% SHCS sequences. Our data suggests that marginalized-populations are underrepresented in the SHCS. However, the limited size of outbreaks among non-SHCS patients in-care implies that no major HIV outbreak in Switzerland was missed by the SHCS surveillance. This study demonstrates the potential of sequence data to assess and extend the scope of infectious-disease surveillance.

  20. Coexistence of structured populations with size-based prey selection

    DEFF Research Database (Denmark)

    Hartvig, Martin; Andersen, Ken Haste

    2013-01-01

    Abstract Species with a large adult-offspring size ratio and a preferred predator–prey mass ratio undergo ontogenetic trophic niche shift(s) throughout life. Trophic interactions between such species vary throughout life, resulting in different species-level interaction motifs depending on the ma......Abstract Species with a large adult-offspring size ratio and a preferred predator–prey mass ratio undergo ontogenetic trophic niche shift(s) throughout life. Trophic interactions between such species vary throughout life, resulting in different species-level interaction motifs depending...... on the maximum adult sizes and population size distributions. We explore the assembly and potential for coexistence of small communities where all species experience ontogenetic trophic niche shifts. The life-history of each species is described by a physiologically structured model and species identity...... there is a large scope for coexistence of two species, the scope for coexistence of three species is limited and we conclude that further trait differentiation is required for coexistence of more species-rich size-structured communities....

  1. HIV Prevention Among Transgender Populations: Knowledge Gaps and Evidence for Action.

    Science.gov (United States)

    Poteat, Tonia; Malik, Mannat; Scheim, Ayden; Elliott, Ayana

    2017-08-01

    The purpose of this review is to summarize the available evidence-based HIV prevention interventions tailored for transgender people. A limited number of evidence-based HIV prevention interventions have been tested with transgender populations. Most existing interventions target behavior change among transgender women, with only one HIV prevention program evaluated for transgender men. Studies addressing biomedical interventions for transgender women are ongoing. Few interventions address social and structural barriers to HIV prevention, such as stigma, discrimination, and poverty. Evidence-based multi-level interventions that address the structural, biomedical, and behavioral risks for HIV among transgender populations, including transgender men, are needed to address disparities in HIV prevalence. Future research should address not only pre-exposure prophylaxis uptake and condom use but also structural barriers that limit access to these prevention strategies.

  2. Fogging the issue of HIV - barriers for HIV testing in a migrated population from Ethiopia and Eritrea.

    Science.gov (United States)

    Lindkvist, Pille; Johansson, Eva; Hylander, Ingrid

    2015-02-05

    The outcome of HIV treatment has dramatically improved since the introduction of antiretroviral therapy. Studies confirm that if treatment of HIV is initiated when the immune system is not severely affected by the virus the prognosis for the outcome is significantly better. There is also evidence that many immigrants come late for their first HIV test. If found to be HIV positive, and if the immune system is already significantly affected, this will compromise the treatment outcome. This study was performed in an attempt to understand the barriers for early HIV testing in a migrant population from Ethiopia and Eritrea in Stockholm, Sweden. Participants were theoretically sampled and consisted of individuals who had immigrated from Ethiopia and Eritrea. Data were collected using 14 focus group discussions and seven semi-structured interviews. The analysis was performed according to a Grounded Theory approach using the paradigm model. Denial and fear of knowing one's HIV status dominated all aspects of behavior in relation to HIV. The main strategy was a "fogging" of the issue of HIV. People were said to not want to know because this would bring social isolation and exclusion, and it was often believed that treatment did not help. This attitude had strong roots in their culture and past experiences that were brought along to the new country and maintained within the immigrant community. The length of time spent in Sweden seemed to be an important factor affecting the "fogging of the HIV issue". In bridging the gap between the two cultures, Swedish authorities need to find ways to meet the needs of both earlier and newly arrived immigrants as well as the second generation of immigrants. This will require adjusting and updating the information that is given to these different sub-groups of Ethiopian and Eritrean immigrants. Appropriate access to healthcare for a diverse population obviously requires more than simply providing the healthcare services.

  3. Population size estimation of men who have sex with men through the network scale-up method in Japan.

    Directory of Open Access Journals (Sweden)

    Satoshi Ezoe

    Full Text Available BACKGROUND: Men who have sex with men (MSM are one of the groups most at risk for HIV infection in Japan. However, size estimates of MSM populations have not been conducted with sufficient frequency and rigor because of the difficulty, high cost and stigma associated with reaching such populations. This study examined an innovative and simple method for estimating the size of the MSM population in Japan. We combined an internet survey with the network scale-up method, a social network method for estimating the size of hard-to-reach populations, for the first time in Japan. METHODS AND FINDINGS: An internet survey was conducted among 1,500 internet users who registered with a nationwide internet-research agency. The survey participants were asked how many members of particular groups with known population sizes (firepersons, police officers, and military personnel they knew as acquaintances. The participants were also asked to identify the number of their acquaintances whom they understood to be MSM. Using these survey results with the network scale-up method, the personal network size and MSM population size were estimated. The personal network size was estimated to be 363.5 regardless of the sex of the acquaintances and 174.0 for only male acquaintances. The estimated MSM prevalence among the total male population in Japan was 0.0402% without adjustment, and 2.87% after adjusting for the transmission error of MSM. CONCLUSIONS: The estimated personal network size and MSM prevalence seen in this study were comparable to those from previous survey results based on the direct-estimation method. Estimating population sizes through combining an internet survey with the network scale-up method appeared to be an effective method from the perspectives of rapidity, simplicity, and low cost as compared with more-conventional methods.

  4. Key populations and human rights in the context of HIV services rendition in Ghana.

    Science.gov (United States)

    Laar, Amos; DeBruin, Debra

    2017-08-02

    In line with its half century old penal code, Ghana currently criminalizes and penalizes behaviors of some key populations - populations deemed to be at higher risk of acquiring or transmitting Human Immunodeficiency Virus (HIV). Men who have sex with men (MSM), and sex workers (SWs) fit into this categorization. This paper provides an analysis of how enactment and implementation of rights-limiting laws not only limit rights, but also amplify risk and vulnerability to HIV in key and general populations. The paper derives from a project that assessed the ethics sensitivity of key documents guiding Ghana's response to its HIV epidemic. Assessment was guided by leading frameworks from public health ethics, and relevant articles from the international bill of rights. Ghana's response to her HIV epidemic does not adequately address the rights and needs of key populations. Even though the national response has achieved some public health successes, palpable efforts to address rights issues remain nascent. Ghana's guiding documents for HIV response include no advocacy for decriminalization, depenalization or harm reduction approaches for these key populations. The impact of rights-restricting codes on the nation's HIV epidemic is real: criminalization impedes key populations' access to HIV prevention and treatment services. Given that they are bridging populations, whatever affects the Ghanaian key populations directly, affects the general population indirectly. The right to the highest attainable standard of health, without qualification, is generally acknowledged as a fundamental human right. Unfortunately, this right currently eludes the Ghanaian SW and MSM. The paper endorses decriminalization as a means of promoting this right. In the face of opposition to decriminalization, the paper proposes specific harm reduction strategies as approaches to promote health and uplift the diminished rights of key populations. Thus the authors call on Ghana to remove impediments to

  5. Harvesting Renewable Resources of Population with Size Structure and Diffusion

    Directory of Open Access Journals (Sweden)

    Qiang-Jun Xie

    2014-01-01

    Full Text Available The aim of this work is to explore the optimal exploitation way for a biological resources model incorporating individual’s size difference and spatial effects. The existence of a unique nonnegative solution to the state system is shown by means of Banach’s fixed point theorem, and the continuous dependence of the population density with the harvesting effort is given. The optimal harvesting strategy is established via normal cone and adjoint system technique. Some conditions are found to assure that there is only one optimal policy.

  6. Population size does not explain past changes in cultural complexity.

    Science.gov (United States)

    Vaesen, Krist; Collard, Mark; Cosgrove, Richard; Roebroeks, Wil

    2016-04-19

    Demography is increasingly being invoked to account for features of the archaeological record, such as the technological conservatism of the Lower and Middle Pleistocene, the Middle to Upper Paleolithic transition, and cultural loss in Holocene Tasmania. Such explanations are commonly justified in relation to population dynamic models developed by Henrich [Henrich J (2004)Am Antiq69:197-214] and Powell et al. [Powell A, et al. (2009)Science324(5932):1298-1301], which appear to demonstrate that population size is the crucial determinant of cultural complexity. Here, we show that these models fail in two important respects. First, they only support a relationship between demography and culture in implausible conditions. Second, their predictions conflict with the available archaeological and ethnographic evidence. We conclude that new theoretical and empirical research is required to identify the factors that drove the changes in cultural complexity that are documented by the archaeological record.

  7. The dynamics of endemic malaria in populations of varying size

    International Nuclear Information System (INIS)

    Ngwa, G.A.

    2001-10-01

    A mathematical model for endemic malaria involving variable human and mosquito populations is analysed. A threshold parameter R 0 exists and the disease can persist if and only if R 0 exceeds 1. R 0 is seen to be a generalisation of the basic reproduction ratio associated with the Ross-Macdonald model for malaria transmission. The disease free equilibrium always exist and is globally stable when R 0 is below 1. A perturbation analysis is used to approximate the endemic equilibrium in the important case where the disease related death rate is nonzero. A diffusion approximation is used to approximate the quasi-stationary distribution of the associated stochastic model. Numerical simulations show that when R 0 is distinctly greater than 1, the endemic deterministic equilibrium is globally stable. Furthermore, in quasi-stationarity, the stochastic process undergoes oscillations about a mean population whose size can be approximated by the stable endemic deterministic equilibrium. (author)

  8. Sample size for monitoring sirex populations and their natural enemies

    Directory of Open Access Journals (Sweden)

    Susete do Rocio Chiarello Penteado

    2016-09-01

    Full Text Available The woodwasp Sirex noctilio Fabricius (Hymenoptera: Siricidae was introduced in Brazil in 1988 and became the main pest in pine plantations. It has spread to about 1.000.000 ha, at different population levels, in the states of Rio Grande do Sul, Santa Catarina, Paraná, São Paulo and Minas Gerais. Control is done mainly by using a nematode, Deladenus siricidicola Bedding (Nematoda: Neothylenchidae. The evaluation of the efficiency of natural enemies has been difficult because there are no appropriate sampling systems. This study tested a hierarchical sampling system to define the sample size to monitor the S. noctilio population and the efficiency of their natural enemies, which was found to be perfectly adequate.

  9. Mental distress in the general population in Zambia: Impact of HIV and social factors

    Directory of Open Access Journals (Sweden)

    Chipimo Peter J

    2009-08-01

    Full Text Available Abstract Background Population level data on mental health from Africa are limited, but available data indicate mental problems to represent a substantial public health problem. The negative impact of HIV on mental health suggests that this could particularly be the case in high prevalence populations. We examined the prevalence of mental distress, distribution patterns and the ways HIV might influence mental health among men and women in a general population. Methods The relationship between HIV infection and mental distress was explored using a sample of 4466 participants in a population-based HIV survey conducted in selected rural and urban communities in Zambia in 2003. The Self-reporting questionnaire-10 (SRQ-10 was used to assess global mental distress. Weights were assigned to the SRQ-10 responses based on DSM IV criteria for depression and a cut off point set at 7/20 for probable cases of mental distress. A structural equation modeling (SEM was established to assess the structural relationship between HIV infection and mental distress in the model, with maximum likelihood ratio as the method of estimation. Results The HIV prevalence was 13.6% vs. 18% in the rural and urban populations, respectively. The prevalence of mental distress was substantially higher among women than men and among groups with low educational attainment vs. high. The results of the SEM showed a close fit with the data. The final model revealed that self-rated health and self perceived HIV risk and worry of being HIV infected were important mediators between underlying factors, HIV infection and mental distress. The effect of HIV infection on mental distress was both direct and indirect, but was particularly strong through the indirect effects of health ratings and self perceived risk and worry of HIV infection. Conclusion These findings suggest a strong effect of HIV infection on mental distress. In this population where few knew their HIV status, this effect was

  10. Future challenges for clinical care of an ageing population infected with HIV: a modelling study

    NARCIS (Netherlands)

    Smit, Mikaela; Brinkman, Kees; Geerlings, Suzanne; Smit, Colette; Thyagarajan, Kalyani; Sighem, Ard van; de Wolf, Frank; Hallett, Timothy B.

    2015-01-01

    The population infected with HIV is getting older and these people will increasingly develop age-related non-communicable diseases (NCDs). We aimed to quantify the scale of the change and the implications for HIV care in the Netherlands in the future. We constructed an individual-based model of the

  11. Economic consequences of population size, structure and growth.

    Science.gov (United States)

    Lee, R

    1983-01-01

    There seems to be 4 major approaches to conceptualizing and modeling demographic influences on economic and social welfare. These approaches are combined in various ways to construct richer and more comprehensive models. The basic approaches are: demographic influences on household or family behavior; population growth and reproducible capital; population size and fixed factors; and population and advantages of scale. These 4 models emphasize the supply side effects of population. A few of the ways in which these theories have been combined are sketched. Neoclassical growth models often have been combined with age distributed populations of individuals (or households), assumed to pursue optimal life cycle consumption and saving. In some well known development models, neoclassical growth models for the modern sector are linked by labor markets and migration to fixed factor (land) models of the traditional (agricultural) sector. A whole series of macro simulation models for developed and developing countries was based on single sector neoclassical growth models with age distributed populations. Yet, typically the household level foundations of assumed age distribution effects were not worked out. Simon's (1977) simulation models are in a class by themselves, for they are the only models that attempt to incorporate all the kinds of effects discussed. The economic demography of the individual and family cycle, as it is affected by regimes of fertility, mortality, and nuptiality, taken as given, are considered. The examination touches on many of the purported consequences of aggregate population growth and age composition, since so many of these are based implicitly or explicitly on assertions about micro level behavior. Demographic influences on saving and consumption, on general labor supply and female labor supply, and on problems of youth and old age dependency frequently fall in this category. Finally, attention is focused specifically on macro economic issues in

  12. Measuring Sexual Behavior Stigma to Inform Effective HIV Prevention and Treatment Programs for Key Populations

    Science.gov (United States)

    Hargreaves, James R; Sprague, Laurel; Stangl, Anne L; Baral, Stefan D

    2017-01-01

    Background The levels of coverage of human immunodeficiency virus (HIV) treatment and prevention services needed to change the trajectory of the HIV epidemic among key populations, including gay men and other men who have sex with men (MSM) and sex workers, have consistently been shown to be limited by stigma. Objective The aim of this study was to propose an agenda for the goals and approaches of a sexual behavior stigma surveillance effort for key populations, with a focus on collecting surveillance data from 4 groups: (1) members of key population groups themselves (regardless of HIV status), (2) people living with HIV (PLHIV) who are also members of key populations, (3) members of nonkey populations, and (4) health workers. Methods We discuss strengths and weaknesses of measuring multiple different types of stigma including perceived, anticipated, experienced, perpetrated, internalized, and intersecting stigma as measured among key populations themselves, as well as attitudes or beliefs about key populations as measured among other groups. Results With the increasing recognition of the importance of stigma, consistent and validated stigma metrics for key populations are needed to monitor trends and guide immediate action. Evidence-based stigma interventions may ultimately be the key to overcoming the barriers to coverage and retention in life-saving antiretroviral-based HIV prevention and treatment programs for key populations. Conclusions Moving forward necessitates the integration of validated stigma scales in routine HIV surveillance efforts, as well as HIV epidemiologic and intervention studies focused on key populations, as a means of tracking progress toward a more efficient and impactful HIV response. PMID:28446420

  13. HIV incidence from the first population-based cohort study in India.

    Science.gov (United States)

    Dandona, Lalit; Kumar, G Anil; Lakshmi, Vemu; Ahmed, G Md Mushtaq; Akbar, Mohammed; Ramgopal, Sri P; Sudha, Talasila; Alary, Michel; Dandona, Rakhi

    2013-07-17

    Understanding about who acquires new HIV infection and the determinants of why some persons get infected and others do not is fundamental to controlling HIV in the population. We assess HIV incidence and its associations in the population of a high HIV burden district in Andhra Pradesh state in southern India by a population-based longitudinal cohort study. We re-surveyed a population-based cohort of 12,617 adults in Guntur district of Andhra Pradesh for which we had reported a baseline HIV prevalence of 1.72% (rural 1.64%, urban 1.89%) among the 15-49 years age group in 2004-2005. We conducted interviews to assess risk behaviour and performed HIV testing again in 2010-2011. We assessed the rate of new HIV infection and its associations using multiple logistic regression. The participation rate in the follow-up was 74.9% and 63.9% of the baseline rural and urban samples, respectively. Over a mean follow-up of 5.63 years, the incidence of HIV was 1.26 per 1000 person-years (95% CI 0.83-1.69), after adjusting for slight compositional bias in the follow-up sample. The incidence per 1000 person-years was higher among rural men (1.68) than urban men (0.85), and among rural women (1.28) than urban women (0.54). The strongest association with incidence was a HIV positive spouse in the baseline for both men (odds ratio 266, 95% CI 62-1137) and women (odds ratio 28, 95% CI 9-88). Among men the other significant associations with HIV incidence were frequent use of condom for sex over the past 6 months, non-circumcision, more than one lifetime woman sex partner or ever visited sex worker, and transport-related occupation; for women the other significant associations were having had HIV testing other than antenatal check-up, previously married but currently not, and tobacco use. These first population-based cohort incidence data from India suggest that rural areas of high HIV burden states would need more attention to prevent new HIV infections, and that spouses of HIV

  14. Mobile populations and HIV/AIDS in Central America and Mexico: research for action.

    Science.gov (United States)

    Bronfman, Mario N; Leyva, Rene; Negroni, Mirka J; Rueda, Celina M

    2002-12-01

    To present a multi-centre study that analyses the socioeconomic, cultural and political contexts that give rise to population mobility, and its relationship to vulnerability to sexually transmitted infections (STI)/HIV/AIDS, in order to provide information that can be used to design appropriate and focused interventions. In each of 11 transit stations (border towns, port cities, areas where mobile populations congregate) in Central America and Mexico, a household survey of the local population was conducted to analyse demographic, socioeconomic characteristics, and information known and opinions held about HIV/AIDS and mobile populations. In-depth interviews with key informants, community members and mobile populations were held to ascertain knowledge about prevention and transmission of STI/HIV/AIDS. Likewise, an ethnographic study was undertaken to identify interactions between local and mobile populations. The transit stations share low educational levels among the local population, few public services, repeated human rights violations, violence, poverty and corrupt authorities. Within this social context, transactional sex, sex for survival, rape and non-professional commercial sex happen in conditions that increase the risk of the transmission of STI/HIV, such as infrequent condom use. Migrant women and sex workers are particularly vulnerable in this context. A wide gap exists between information about STI/HIV transmission and reported prevention practices. Given the conditions that exist in these transit stations, interventions should be multisectoral, sustainable, and should defend the human rights of various groups, including women and people living with HIV/AIDS.

  15. Selection for altruism through random drift in variable size populations

    Directory of Open Access Journals (Sweden)

    Houchmandzadeh Bahram

    2012-05-01

    Full Text Available Abstract Background Altruistic behavior is defined as helping others at a cost to oneself and a lowered fitness. The lower fitness implies that altruists should be selected against, which is in contradiction with their widespread presence is nature. Present models of selection for altruism (kin or multilevel show that altruistic behaviors can have ‘hidden’ advantages if the ‘common good’ produced by altruists is restricted to some related or unrelated groups. These models are mostly deterministic, or assume a frequency dependent fitness. Results Evolutionary dynamics is a competition between deterministic selection pressure and stochastic events due to random sampling from one generation to the next. We show here that an altruistic allele extending the carrying capacity of the habitat can win by increasing the random drift of “selfish” alleles. In other terms, the fixation probability of altruistic genes can be higher than those of a selfish ones, even though altruists have a smaller fitness. Moreover when populations are geographically structured, the altruists advantage can be highly amplified and the fixation probability of selfish genes can tend toward zero. The above results are obtained both by numerical and analytical calculations. Analytical results are obtained in the limit of large populations. Conclusions The theory we present does not involve kin or multilevel selection, but is based on the existence of random drift in variable size populations. The model is a generalization of the original Fisher-Wright and Moran models where the carrying capacity depends on the number of altruists.

  16. Psychiatric symptoms among an HIV positive Urban Population in ...

    African Journals Online (AJOL)

    RICHY

    frequently psychiatric symptoms in an HIV positive adult ... affect the outcome of HIV disease. Firstly ... ignoring the serious consequences and impact the have on ... separated. 10. 5.4 divorced. 19. 10.3 widowed. 48. 26.0. Educational level.

  17. Scaling-up HIV responses with key populations in West Africa.

    Science.gov (United States)

    Wheeler, Tisha; Wolf, R Cameron; Kapesa, Laurent; Cheng Surdo, Alison; Dallabetta, Gina

    2015-03-01

    Despite decades of HIV responses in pockets of West and Central Africa (WCA), the HIV response with key populations remains an understudied area. Recently, there has been a proliferation of studies highlighting epidemiologic and behavioral data that challenge attitudes of complacency among donors and country governments uncomfortable in addressing key populations. The articles in this series highlight new studies that provide a better understanding of the epidemiologic and structural burden facing key populations in the WCA region and how to improve responses through more effective targeting. Key populations face pervasive structural barriers including institutional and sexual violence and an intersection of stigma, criminalization, and marginalization as sexual minorities. Despite decades of smaller interventions that have shown the importance of integrated services for key populations, there remains incongruent provision of outreach or testing or family planning pointing to sustained risk. There remains an incongruent resource provision for key populations where they shoulder the burden of HIV and their access to services alone could turn around HIV epidemics within the region. These proximal and distal determinants must be addressed in regional efforts, led by the community, and resourced for scale, targeting those most at risk for the acquisition and transmission of HIV. This special issue builds the knowledge base for the region focusing on interventions that remove barriers to service access including treatment uptake for those living with HIV. Better analysis and use of data for strategic planning are shown to lead to more effective targeting of prevention, care, and HIV treatment programs with key populations. These articles further demonstrate the immediate need for comprehensive action to address HIV among key populations throughout the WCA region.

  18. THE MASSIVE SATELLITE POPULATION OF MILKY-WAY-SIZED GALAXIES

    International Nuclear Information System (INIS)

    Rodríguez-Puebla, Aldo; Avila-Reese, Vladimir; Drory, Niv

    2013-01-01

    for the ΛCDM cosmology. However, we confirm that the maximum circular velocity, v max , of the subhalos of satellites smaller than m * ∼ 10 8 M ☉ is systematically larger than the v max inferred from current observational studies of the MW bright dwarf satellites; different from previous works, this conclusion is based on an analysis of the overall population of MW-sized galaxies. Some pieces of evidence suggest that the issue could refer only to satellite dwarfs but not to central dwarfs, then environmental processes associated with dwarfs inside host halos combined with supernova-driven core expansion should be on the basis of the lowering of v max

  19. HIV decline associated with changes in risk behaviours among young key populations in Nepal: analysis of population-based HIV prevalence surveys between 2001 and 2012.

    Science.gov (United States)

    Deuba, Keshab; Ekström, Anna Mia; Tomson, Göran; Shrestha, Rachana; Marrone, Gaetano

    2017-08-01

    We assessed changes in HIV prevalence and risk behaviours among young key populations in Nepal. A total of 7505 participants (aged 16-24 years) from key populations who were at increased risk of HIV infection (2767 people who inject drugs (PWID); 852 men who have sex with men/transgender (MSM/TG); 2851 female sex workers (FSW) and 1035 male labour migrants) were recruited randomly over a 12-year period, 2001-2012. Local epidemic zones of Nepal (Kathmandu valley, Pokhara valley, Terai Highway and West to Far West hills) were analysed separately. We found a very strong and consistent decline in HIV prevalence over the past decade in different epidemic zones among PWID and MSM/TG in Kathmandu, the capital city, most likely due to a parallel increase in safe needle and syringe use and increased condom use. A decrease in HIV prevalence in 22 Terai highway districts, sharing an open border with India, was also consistent with increased condom use among FSW. Among male labour migrants, HIV prevalence was low throughout the period in the West to Far West hilly regions. Condom use by migrant workers involved with FSW abroad increased while their condom use with Nepalese FSW declined. Other risk determinants such as mean age at starting first injection, injection frequency, place of commercial sex solicitation, their mean age when leaving to work abroad did not change consistently across epidemic zones among the young key populations under study. In Nepal, the decline in HIV prevalence over the past decade was remarkably significant and consistent with an increase in condom use and safer use of clean needles and syringes. However, diverging trends in risk behaviours across local epidemic zones of Nepal suggest a varying degree of implementation of national HIV prevention policies. This calls for continued preventive efforts as well as surveillance to sustain the observed downward trend.

  20. Size estimation, HIV prevalence and risk behaviours of female sex workers in Pakistan

    International Nuclear Information System (INIS)

    Altaf, A.; Aga, A.; McKinizie, M.H.; Abbas, Q.; Jafri, S.B.

    2012-01-01

    Objective: To provide size estimation and to determine risky behaviours and HIV prevalence among female sex workers in Pakistan, which has progressed from a low to concentrated level of HIV epidemic. Methods: A cross-sectional study (geographic mapping and integrated behavioural and biological survey-IBBS) was conducted between August 2005 to January 2006 in Karachi, Hyderabad and Sukkur. A detailed questionnaire and dry blood spot (DBS) specimen for HIV testing were collected by trained interviewers after informed consent. The study was ethically approved by review boards in Canada and Pakistan. Results: About 14,900 female sex workers were estimated to be functional in Sindh. A total of 1158 of them were interviewed for the study. Average age of sex workers was 27.4+- 6.7 years, and the majority 787 (67.9%) were married, and uneducated 764 (65.9%). Sindhi (26.4%) was the predominant ethnicity. Mean number of paid clients was 2.1+-1.2. Three workers were confirmed HIV positive (0.75%, 95 percent CI 0.2-2.2%) from Karachi. Condom use at last sexual act was highest (68%) among brothel-based workers from Karachi, and the lowest in Sukkur where only 1.3% street-based workers reported using a condom at last sexual act. Overall use of illicit drugs through injections was negligible. Conclusion: HIV prevalence among female sex workers in Sindh, Pakistan is low but risky behaviours are present. Well organised service delivery programmes can help promoting safer practices. (author)

  1. Sizing the star cluster population of the Large Magellanic Cloud

    Science.gov (United States)

    Piatti, Andrés E.

    2018-04-01

    The number of star clusters that populate the Large Magellanic Cloud (LMC) at deprojected distances knowledge of the LMC cluster formation and dissolution histories, we closely revisited such a compilation of objects and found that only ˜35 per cent of the previously known catalogued clusters have been included. The remaining entries are likely related to stellar overdensities of the LMC composite star field, because there is a remarkable enhancement of objects with assigned ages older than log(t yr-1) ˜ 9.4, which contrasts with the existence of the LMC cluster age gap; the assumption of a cluster formation rate similar to that of the LMC star field does not help to conciliate so large amount of clusters either; and nearly 50 per cent of them come from cluster search procedures known to produce more than 90 per cent of false detections. The lack of further analyses to confirm the physical reality as genuine star clusters of the identified overdensities also glooms those results. We support that the actual size of the LMC main body cluster population is close to that previously known.

  2. The HIV Care Continuum among Female Sex Workers: A Key Population in Lilongwe, Malawi.

    Directory of Open Access Journals (Sweden)

    Kathryn Elizabeth Lancaster

    Full Text Available The HIV care continuum among female sex workers (FSW, a key population, has not been well characterized, especially within the generalized epidemics of sub-Saharan Africa. This was the first study to characterize the HIV care continuum among FSW in Lilongwe, Malawi.From July through September 2014, we used venue-based sampling to enroll 200 adult FSW in Lilongwe, Malawi into a cross-sectional evaluation assessing HIV care continuum outcomes. Seropositive FSW, identified using HIV rapid testing, received rapid CD4 counts in addition to viral loads using dried blood spots. We calculated proportions of HIV-infected FSW who had history of care, were on ART, and had suppressed viral load and we used Poisson regression to estimate the associations of demographic characteristics and transmission risk behaviors with each outcome.HIV seroprevalence was 69% (n = 138. Among all FSW the median age was 24 years (IQR: 22-28. Among the 20% who were newly diagnosed and reported previously testing negative, the median time since last HIV test was 11 months (interquartile range: 3-17. The majority (69% of HIV-infected FSW had a history of HIV care, 52% reported current ART use, and 45% were virally suppressed. Of the FSW who reported current ART use, 86% were virally suppressed. Transmission risk behaviors were not associated with continuum outcomes.FSW in Lilongwe were predominately young and have a high HIV prevalence. Only half of HIV-infected FSW reported current ART use, but the majority of those on ART were virally suppressed. To reduce ongoing transmission and improve health outcomes, increased HIV testing, care engagement, and ART coverage is urgently needed among FSW. Universal testing and treatment strategies for all FSW in Malawi must be strongly considered.

  3. Population genomics of eusocial insects: the costs of a vertebrate-like effective population size.

    Science.gov (United States)

    Romiguier, J; Lourenco, J; Gayral, P; Faivre, N; Weinert, L A; Ravel, S; Ballenghien, M; Cahais, V; Bernard, A; Loire, E; Keller, L; Galtier, N

    2014-03-01

    The evolution of reproductive division of labour and social life in social insects has lead to the emergence of several life-history traits and adaptations typical of larger organisms: social insect colonies can reach masses of several kilograms, they start reproducing only when they are several years old, and can live for decades. These features and the monopolization of reproduction by only one or few individuals in a colony should affect molecular evolution by reducing the effective population size. We tested this prediction by analysing genome-wide patterns of coding sequence polymorphism and divergence in eusocial vs. noneusocial insects based on newly generated RNA-seq data. We report very low amounts of genetic polymorphism and an elevated ratio of nonsynonymous to synonymous changes – a marker of the effective population size – in four distinct species of eusocial insects, which were more similar to vertebrates than to solitary insects regarding molecular evolutionary processes. Moreover, the ratio of nonsynonymous to synonymous substitutions was positively correlated with the level of social complexity across ant species. These results are fully consistent with the hypothesis of a reduced effective population size and an increased genetic load in eusocial insects, indicating that the evolution of social life has important consequences at both the genomic and population levels. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  4. HIV/AIDS Related Stigma and Discrimination against PLWHA in Nigerian Population.

    Science.gov (United States)

    Dahlui, Maznah; Azahar, Nazar; Bulgiba, Awang; Zaki, Rafdzah; Oche, Oche Mansur; Adekunjo, Felix Oluyemi; Chinna, Karuthan

    2015-01-01

    HIV/AIDS remain a major public health concern in Nigeria. People living with HIV/AIDS (PLWHA) face not only personal medical problems but also social problems associated with the disease such as stigma and discriminatory attitudes. This study provides an insight into HIV/AIDS related stigma and discrimination against PLWHA in Nigeria. The data for this study was extracted from the 2013 Nigeria Demographic and Health Survey conducted by the National Population Commission. All men and women aged 15-49 years, permanent residents and visitors of the households were eligible for the interview. Several questionnaires were used in the survey, some covering questions on HIV/AIDS. A total of 56 307 men and women aged 15-49 years participated in this national survey. About half of the population in Nigeria have HIV stigma. Younger persons, men, those without formal education and those within poor wealth index are more likely to have stigma towards PLWHA. In addition, married people are more likely to have stigma on PLWHA and are more likely to blame PLWHA for bringing the disease to the community. Also about half of the population discriminates against PLWHA. However, those with higher levels of education and those from higher wealth index seem to be more compassionate towards PLWHA. About 70% in the population are willing to care for relative with AIDS, even more so among those with higher level of education. There is a high level of HIV stigma and discrimination against PLWHA in the Nigerian population. Education seems to play a major role in the society with respect to HIV stigma and discrimination against PLWHA. Educating the population with factual information on HIV/AIDS is needed to reduce stigma and discrimination towards PLWHA in the community.

  5. HIV/AIDS Related Stigma and Discrimination against PLWHA in Nigerian Population

    Science.gov (United States)

    Bulgiba, Awang; Oche, Oche Mansur; Adekunjo, Felix Oluyemi

    2015-01-01

    Background HIV/AIDS remain a major public health concern in Nigeria. People living with HIV/AIDS (PLWHA) face not only personal medical problems but also social problems associated with the disease such as stigma and discriminatory attitudes. This study provides an insight into HIV/AIDS related stigma and discrimination against PLWHA in Nigeria. Methods The data for this study was extracted from the 2013 Nigeria Demographic and Health Survey conducted by the National Population Commission. All men and women aged 15–49 years, permanent residents and visitors of the households were eligible for the interview. Several questionnaires were used in the survey, some covering questions on HIV/AIDS. Results A total of 56 307 men and women aged 15–49 years participated in this national survey. About half of the population in Nigeria have HIV stigma. Younger persons, men, those without formal education and those within poor wealth index are more likely to have stigma towards PLWHA. In addition, married people are more likely to have stigma on PLWHA and are more likely to blame PLWHA for bringing the disease to the community. Also about half of the population discriminates against PLWHA. However, those with higher levels of education and those from higher wealth index seem to be more compassionate towards PLWHA. About 70% in the population are willing to care for relative with AIDS, even more so among those with higher level of education. Conclusion There is a high level of HIV stigma and discrimination against PLWHA in the Nigerian population. Education seems to play a major role in the society with respect to HIV stigma and discrimination against PLWHA. Educating the population with factual information on HIV/AIDS is needed to reduce stigma and discrimination towards PLWHA in the community. PMID:26658767

  6. Oncogenic HPV among HIV infected female population in West Bengal, India

    Directory of Open Access Journals (Sweden)

    Sengupta Sharmila

    2011-03-01

    Full Text Available Abstract Background Prevalence of both cervical cancer and Human Immunodeficiency Virus (HIV infection are very high in India. Natural history of Human Papilloma Virus (HPV infection is known to be altered in HIV positive women and there is an increased possibility of persistence of HPV infections in this population. Therefore, this study was conducted to understand the epidemiology and circulating genotypes of oncogenic HPV among HIV positive and negative female population in West Bengal, India. Methods In this hospital-based cross-sectional study, 93 known HIV positive females attending a pre-ART registration clinic and 1106 HIV negative females attending a Reproductive and Child Health Care Clinic were subjected to study. Cervical cell samples collected from the study population were tested for the presence of HPV 16, 18 using specific primers. Roche PCR assay was used to detect other specific HPV genotypes in the cervical cells specimens of HIV positive cases only. Results Prevalence of HPV 16, 18 among HIV positive females (32.2%; n = 30 was higher than HIV negative females (9.1%; n = 101. About 53% (23/43 of cases with oncogenic HPV were infected with genotypes other than 16, 18 either as single/multiple infections. HPV 18 and HPV 16 were the predominant genotypes among HIV positive and HIV negative subjects respectively. Oncogenic HPV was not found to be associated with age and duration of sexual exposure. But the presence of HIV was found to a statistically significant predictor oncogenic HPV. Conclusion The currently available HPV vaccines offer protection only against HPV 16 and 18 and some cross- protection to few associated genotypes. These vaccines are therefore less likely to offer protection against cervical cancer in HIV positive women a high percentage of who were infected with non-16 and non-18 oncogenic HPV genotypes. Additionally, there is a lack of sufficient evidence of immunogenicity in HIV infected individuals. Therefore

  7. Sensitivity analysis of effective population size to demographic parameters in house sparrow populations.

    Science.gov (United States)

    Stubberud, Marlene Waege; Myhre, Ane Marlene; Holand, Håkon; Kvalnes, Thomas; Ringsby, Thor Harald; Saether, Bernt-Erik; Jensen, Henrik

    2017-05-01

    The ratio between the effective and the census population size, Ne/N, is an important measure of the long-term viability and sustainability of a population. Understanding which demographic processes that affect Ne/N most will improve our understanding of how genetic drift and the probability of fixation of alleles is affected by demography. This knowledge may also be of vital importance in management of endangered populations and species. Here, we use data from 13 natural populations of house sparrow (Passer domesticus) in Norway to calculate the demographic parameters that determine Ne/N. Using the global variance-based Sobol' method for the sensitivity analyses, we found that Ne/N was most sensitive to demographic variance, especially among older individuals. Furthermore, the individual reproductive values (that determine the demographic variance) were most sensitive to variation in fecundity. Our results draw attention to the applicability of sensitivity analyses in population management and conservation. For population management aiming to reduce the loss of genetic variation, a sensitivity analysis may indicate the demographic parameters towards which resources should be focused. The result of such an analysis may depend on the life history and mating system of the population or species under consideration, because the vital rates and sex-age classes that Ne/N is most sensitive to may change accordingly. © 2017 John Wiley & Sons Ltd.

  8. The role of HIV/AIDS committees in effective workplace governance of HIV/AIDS in South African small and medium-sized enterprises (SMEs).

    Science.gov (United States)

    Vaas, Jocelyn R

    2008-04-01

    The primary purpose of this study was to assess the role, status and scope of workplace HIV/AIDS committees as a means of effective workplace governance of the HIV/AIDS impact, and their role in extending social protective HIV/AIDS-related rights to employees. In-depth qualitative case studies were conducted in five South African small and medium-sized enterprises (SMEs) that were actively implementing HIV/AIDS policies and programmes. Companies commonly implemented HIV/AIDS policies and programmes through a workplace committee dedicated to HIV/AIDS or a generic committee dealing with issues other than HIV/ AIDS. Management, through the human resources department and the occupational health practitioner often drove initial policy formulation, and had virtually sole control of the HIV/AIDS budget. Employee members of committees were mostly volunteers, and were often production or blue collar employees, while there was a notable lack of participation by white-collar employees, line management and trade unions. While the powers of workplace committees were largely consultative, employee committee members often managed in an indirect manner to secure and extend social protective rights on HIV/AIDS to employees, and monitor their effective implementation in practice. In the interim, workplace committees represented one of the best means to facilitate more effective workplace HIV/AIDS governance. However, the increased demands on collective bargaining as a result of an anticipated rises in AIDS-related morbidity and mortality might prove to be beyond the scope of such voluntary committees in the longer term.

  9. 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

  10. Application of Network Scale Up Method in the Estimation of Population Size for Men Who Have Sex with Men in Shanghai, China.

    Directory of Open Access Journals (Sweden)

    Jun Wang

    Full Text Available Men who have sex with men (MSM are at high risk of HIV infection. For developing proper interventions, it is important to know the size of MSM population. However, size estimation of MSM populations is still a significant public health challenge due to high cost, hard to reach and stigma associated with the population.We aimed to estimate the social network size (c value in general population and the size of MSM population in Shanghai, China by using the net work scale-up method.A multistage random sampling was used to recruit participants aged from 18 to 60 years who had lived in Shanghai for at least 6 months. The "known population method" with adjustment of backward estimation and regression model was applied to estimate the c value. And the MSM population size was further estimated using an adjusted c value taking into account for the transmission effect through social respect level towards MSM.A total of 4017 participants were contacted for an interview, and 3907 participants met the inclusion criterion. The social network size (c value of participants was 236 after adjustment. The estimated size of MSM was 36354 (95% CI: 28489-44219 for the male Shanghaies aged 18 to 60 years, and the proportion of MSM among the total male population aged 18 to 60 years in Shanghai was 0.28%.We employed the network scale-up method and used a wide range of data sources to estimate the size of MSM population in Shanghai, which is useful for HIV prevention and intervention among the target population.

  11. Access to HIV community services by vulnerable populations: evidence from an enhanced HIV/AIDS surveillance system.

    Science.gov (United States)

    Madden, H C E; Phillips-Howard, P A; Hargreaves, S C; Downing, J; Bellis, M A; Vivancos, R; Morley, C; Syed, Q; Cook, P A

    2011-05-01

    HIV disproportionately affects vulnerable populations such as black and minority ethnic groups, men who have sex with men (MSM) and migrants, in many countries including those in the UK. Community organisations in the UK are charitable non-governmental organisations with a proportion of the workforce who volunteer, and provide invaluable additional support for people living with HIV (PLWHIV). Information on their contribution to HIV care in vulnerable groups is relatively sparse. Data generated from an enhanced HIV surveillance system in North West England, UK, was utilised for this study. We aimed to determine the characteristics of individuals who chose to access community services in addition to clinical services (1375 out of 4195 records of PLWHIV in clinical services). Demographic information, risk factors including residency status, uniquely gathered in this region, and deprivation scores were examined. Multivariate logistic regression modelling was conducted to predict the relative effect of patient characteristics on attendance at community services. Attendance at community services was highest in those living in the most, compared with least, deprived areas (p<0.001), and was most evident in MSM and heterosexuals. Compared to white UK nationals attendance was significantly higher in non-UK nationals of uncertain residency status (Adjusted odds ratio [AOR] = 21.91, 95% confidence interval [CI] 10.48-45.83; p<0.001), refugees (AOR = 5.75, 95% CI 3.3-10.03; p<0.001), migrant workers (AOR = 5.48, 95% CI 2.22-13.51; p<0.001) and temporary visitors (AOR = 3.44, 95% CI 1.68-7.05; p<0.001). Community services, initially established predominantly to support MSM, have responded to the changing demography of HIV and reach the most vulnerable members of society. Consequent to their support of migrant populations, community services are vital for the management of HIV in black and minority groups. Paradoxically, this coincides with increasing funding pressures on these

  12. Monitoring the HIV continuum of care in key populations across Europe and Central Asia.

    Science.gov (United States)

    Brown, A E; Attawell, K; Hales, D; Rice, B D; Pharris, A; Supervie, V; Van Beckhoven, D; Delpech, V C; An der Heiden, M; Marcus, U; Maly, M; Noori, T

    2018-05-08

    The aim of the study was to measure and compare national continuum of HIV care estimates in Europe and Central Asia in three key subpopulations: men who have sex with men (MSM), people who inject drugs (PWID) and migrants. Responses to a 2016 European Centre for Disease Prevention and Control (ECDC) survey of 55 European and Central Asian countries were used to describe continuums of HIV care for the subpopulations. Data were analysed using three frameworks: Joint United Nations Programme on HIV/AIDS (UNAIDS) 90-90-90 targets; breakpoint analysis identifying reductions between adjacent continuum stages; quadrant analysis categorizing countries using 90% cut-offs for continuum stages. Overall, 29 of 48 countries reported national data for all HIV continuum stages (numbers living with HIV, diagnosed, receiving treatment and virally suppressed). Six countries reported all stages for MSM, seven for PWID and two for migrants. Thirty-one countries did not report data for MSM (34 for PWID and 41 for migrants). In countries that provided key-population data, overall, 63%, 40% and 41% of MSM, PWID and migrants living with HIV were virally suppressed, respectively (compared with 68%, 65% and 68% nationally, for countries reporting key-population data). Variation was observed between countries, with higher outcomes in subpopulations in Western Europe compared with Eastern Europe and Central Asia. Few reporting countries can produce the continuum of HIV care for the three key populations. Where data are available, differences exist in outcomes between the general and key populations. While MSM broadly mirror national outcomes (in the West), PWID and migrants experience poorer treatment and viral suppression. Countries must develop continuum measures for key populations to identify and address inequalities. © 2018 British HIV Association.

  13. Adverse childhood experiences, gender, and HIV risk behaviors: Results from a population-based sample

    Directory of Open Access Journals (Sweden)

    Lin Fang

    2016-12-01

    Full Text Available Recent HIV research suggested assessing adverse childhood experiences (ACEs as contributing factors of HIV risk behaviors. However, studies often focused on a single type of adverse experience and very few utilized population-based data. This population study examined the associations between ACE (individual and cumulative ACE score and HIV risk behaviors. We analyzed the 2012 Behavioral Risk Factor Surveillance Survey (BRFSS from 5 states. The sample consisted of 39,434 adults. Eight types of ACEs that included different types of child abuse and household dysfunctions before the age of 18 were measured. A cumulative score of ACEs was also computed. Logistic regression estimated of the association between ACEs and HIV risk behaviors using odds ratio (OR with 95% confidence intervals (CIs for males and females separately. We found that ACEs were positively associated with HIV risk behaviors overall, but the associations differed between males and females in a few instances. While the cumulative ACE score was associated with HIV risk behaviors in a stepwise manner, the pattern varied by gender. For males, the odds of HIV risk increased at a significant level as long as they experienced one ACE, whereas for females, the odds did not increase until they experienced three or more ACEs. Future research should further investigate the gender-specific associations between ACEs and HIV risk behaviors. As childhood adversities are prevalent among general population, and such experiences are associated with increased risk behaviors for HIV transmission, service providers can benefit from the principles of trauma-informed practice.

  14. Estimation of the effective population size (Ne) and its application in the management of small populations

    DEFF Research Database (Denmark)

    Jimenez Mena, Belen

    2016-01-01

    Effective population size (Ne) is an important concept to understand the evolution of a population. In conservation, Ne is used to assess the threat status of a population, evaluate its genetic viability in the future and set conservation priorities. An accurate estimation of Ne is thus essential....... The main objective of this thesis was to better understand how the estimation of Ne using molecular markers can be improved for use in conservation genetics. As a first step, we undertook a simulation study where three different methods to estimate Ne were investigated. We explored how well these three...... methods performed under different scenarios. This study showed that all three methods performed better when the number of unlinked loci used to make the estimation increased and the minimum number of loci need for an accurate estimation of Ne was 100 SNPs. A general assumption in the estimation of Ne...

  15. Implementing and expanding HIV testing in immigrant populations in Europe: Comparing guideline's recommendations and expert's opinions.

    Science.gov (United States)

    Álvarez-Del Arco, Débora; Monge, Susana; Rivero-Montesdeoca, Yaiza; Burns, Fiona; Noori, Teymur; Del Amo, Julia

    2017-01-01

    Immigrant populations, especially those from endemic countries, living in the European Union (EU) suffer a disproportionate burden of HIV, delayed diagnosis and poorer access to antiretroviral treatment. While International Organisations are developing recommendations aimed at increasing the uptake of HIV testing, the feasibility and real outcomes of these measures remain unexplored. The aim of this review was, firstly to identify the recommendations of the main International Organisations (IO) on HIV testing in immigrants. Secondly, to describe the challenges for implementing and expanding HIV testing and counselling interventions targeting immigrants by interviewing key informants. The importance of HIV testing in immigrants is discussed, along with the appropriateness of universal HIV testing approaches vs most at risk targeted approaches. Also addressed is, pre- and post-HIV test counselling characteristics and community initiatives suitable to reach this population and, finally the legal issues regarding access to treatment for illegal immigrants. Copyright © 2015 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  16. Tuberculosis testing among populations with high HIV risk in Tijuana, Baja California, Mexico.

    Science.gov (United States)

    Velasquez, Michele G; Laniado-Laborin, Rafael; Rodwell, Timothy C; Cerecer, Paris; Lozada, Remedios; Cuevas-Mota, Jazmine; Burgos, Jose Luis; Garfein, Richard S

    2012-07-01

    To assess the prevalence of prior tuberculin skin testing (TST) among populations at risk for HIV infection in Tijuana, Mexico, and to identify factors associated with TST. Sex workers, injection drug users, noninjecting drug users, and homeless persons > 18 years old were recruited by using targeted sampling for risk assessment interviews and serologic testing for HIV and Mycobacterium tuberculosis infection. Univariate and multivariate logistic regression were used to identify correlates of self-reported TST history. Of 502 participants, 38.0% reported prior TST, which was associated with previous incarceration in the United States of America [odds ratio (OR) = 13.38; 95% confidence interval (CI) = 7.37-24.33] and injection drug use (OR = 1.99; 95% CI = 1.27- 3.11). Positive results on serologic tests for M. tuberculosis infection (57%) and HIV (4.2%) were not associated with a prior TST. A history of TST was lower in HIV-positive participants even though TST is indicated for persons with HIV in Mexico. Fewer than half the individuals at high risk for HIV in this study had a history of TST; however, TST was fairly common among those individuals with a prior history of incarceration. Increased tuberculosis screening is needed for populations at risk of contracting HIV in Tijuana, particularly those outside of criminal justice settings.

  17. Brief Report: Anal Cancer in the HIV-Positive Population: Slowly Declining Incidence After a Decade of cART

    NARCIS (Netherlands)

    Richel, Olivier; van der Zee, Ramon P.; Smit, Colette; de Vries, Henry J. C.; Prins, Jan M.

    2015-01-01

    We surveyed trends in incidence (1995-2012) and risk factors for anal cancer in the Dutch HIV-positive population. After an initial increase with a peak incidence in 2005-2006 of 114 [95% confidence interval (CI): 74 to 169] in all HIV+ patients and 168 (95% CI: 103 to 259) in HIV+ men who have sex

  18. Increased risk of dialysis and end-stage renal disease among HIV patients in Denmark compared with the background population

    DEFF Research Database (Denmark)

    Rasch, Magnus G; Helleberg, Marie; Feldt-Rasmussen, Bo

    2014-01-01

    BACKGROUND: HIV patients have increased risk of impaired renal function. We aimed to estimate the incidence of any renal replacement therapy (aRRT) and start of chronic renal replacement therapy (cRRT) among HIV patients compared with population controls. METHODS: In a nationwide, population......-based cohort study we analysed incidence rates (IR), incidence rate ratios (IRR) and risk factors for aRRT and cRRT among HIV patients compared with an age- and gender-matched population control cohort using Poisson regression. RESULTS: We identified 5300 HIV patients and 53 000 population controls. The IRs...

  19. Schistosoma mansoni and HIV infection in a Ugandan population with high HIV and helminth prevalence.

    Science.gov (United States)

    Sanya, Richard E; Muhangi, Lawrence; Nampijja, Margaret; Nannozi, Victoria; Nakawungu, Prossy Kabuubi; Abayo, Elson; Webb, Emily L; Elliott, Alison M

    2015-09-01

    Recent reports suggest that Schistosoma infection may increase the risk of acquiring human immunodeficiency virus (HIV). We used data from a large cross-sectional study to investigate whether Schistosoma mansoni infection is associated with increased HIV prevalence. We conducted a household survey of residents in island fishing communities in Mukono district, Uganda, between October 2012 and July 2013. HIV status was assessed using rapid test kits. Kato-Katz (KK) stool tests and urine-circulating cathodic antigen (CCA) were used to test for Schistosoma infection. Multivariable logistic regression, allowing for the survey design, was used to investigate the association between S. mansoni infection and HIV infection. Data from 1412 participants aged 13 years and older were analysed (mean age 30.3 years, 45% female). The prevalence of HIV was 17.3%. Using the stool Kato-Katz technique on a single sample, S. mansoni infection was detected in 57.2% (719/1257) of participants; urine CCA was positive in 73.8% (478/650) of those tested. S. mansoni infection was not associated with HIV infection. [KK (aOR = 1.04; 95% CI: 0.74-1.47, P = 0.81), CCA (aOR = 1.53; 95% CI: 0.78-3.00, P = 0.19)]. The median S. mansoni egg count per gram was lower in the HIV-positive participants (P = 0.005). These results add to the evidence that S. mansoni has little effect on HIV transmission, but may influence egg excretion. © 2015 The Authors. Tropical Medicine & International Health Published by John Wiley & Sons Ltd.

  20. Change in genetic size of small-closed populations: lessons from a domestic mammal population

    Directory of Open Access Journals (Sweden)

    Farhad Ghafouri-Kesbi

    2010-01-01

    Full Text Available The aim of this study was to monitor changes in genetic size of a small-closed population of Iranian Zandi sheep, by using pedigree information from animals born between 1991 and 2005. The genetic size was assessed by using measures based on the probability of identity-by-descend of genes (coancestry, f, and effective population size, Ne, as well as measures based on probability of gene origin (effective number of founders, f e, effective number of founder genomes, f g, and effective number of non-founder genomes, f ne. Average coancestry, or the degree of genetic similarity of individuals, increased from 0.81% to 1.44% during the period 1993 to 2005, at the same time that Ne decreased from 263 to 93. The observed trend for f e was irregular throughout the experiment in a way that f e was 68, 87, 77, 92, and 80 in 1993, 1996, 1999, 2002, and 2005, respectively. Simultaneously, f g, the most informative effective number, decreased from 61 to 35. The index of genetic diversity (GD which was obtained from estimates of f g,decreased about 2% throughout the period studied. In addition, a noticeable reduction was observed in the estimates of f ne from 595 in 1993 to 61 in 2005. The higher than 1 ratio of f e to f g indicated the presence of bottlenecks and genetic drift in the development of this population of Zandi sheep. From 1993 to 1999, f ne was much higher than f e, thereby indicating that with respect to loss of genetic diversity, the unequal contribution of founders was more important than the random genetic drift in non-founder generations. Subsequently, random genetic drift in non-founder generations was the major reason for f e> f ne. The minimization of average coancestry in new reproductive individuals was recommended as a means of preserving the population against a further loss in genetic diversity.

  1. Competition in size-structured populations: mechanisms inducing cohort formation and population cycles.

    Science.gov (United States)

    de Roos, André M; Persson, Lennart

    2003-02-01

    In this paper we investigate the consequences of size-dependent competition among the individuals of a consumer population by analyzing the dynamic properties of a physiologically structured population model. Only 2 size-classes of individuals are distinguished: juveniles and adults. Juveniles and adults both feed on one and the same resource and hence interact by means of exploitative competition. Juvenile individuals allocate all assimilated energy into development and mature on reaching a fixed developmental threshold. The combination of this fixed threshold and the resource-dependent developmental rate, implies that the juvenile delay between birth and the onset of reproduction may vary in time. Adult individuals allocate all assimilated energy to reproduction. Mortality of both juveniles and adults is assumed to be inversely proportional to the amount of energy assimilated. In this setting we study how the dynamics of the population are influenced by the relative foraging capabilities of juveniles and adults. In line with results that we previously obtained in size-structured consumer-resource models with pulsed reproduction, population cycles primarily occur when either juveniles or adults have a distinct competitive advantage. When adults have a larger per capita feeding rate and are hence competitively superior to juveniles, population oscillations occur that are primarily induced by the fact that the duration of the juvenile period changes with changing food conditions. These cycles do not occur when the juvenile delay is a fixed parameter. When juveniles are competitively superior, two different types of population fluctuations can occur: (1) rapid, low-amplitude fluctuations having a period of half the juvenile delay and (2) slow, large-amplitude fluctuations characterized by a period, which is roughly equal to the juvenile delay. The analysis of simplified versions of the structured model indicates that these two types of oscillations also occur if

  2. Population and antenatal-based HIV prevalence estimates in a high contracepting female population in rural South Africa

    Directory of Open Access Journals (Sweden)

    Barnighausen Till

    2007-07-01

    Full Text Available Abstract Background To present and compare population-based and antenatal-care (ANC sentinel surveillance HIV prevalence estimates among women in a rural South African population where both provision of ANC services and family planning is prevalent and fertility is declining. With a need, in such settings, to understand how to appropriately adjust ANC sentinel surveillance estimates to represent HIV prevalence in general populations, and with evidence of possible biases inherent to both surveillance systems, we explore differences between the two systems. There is particular emphasis on unrepresentative selection of ANC clinics and unrepresentative testing in the population. Methods HIV sero-prevalence amongst blood samples collected from women consenting to test during the 2005 annual longitudinal population-based serological survey was compared to anonymous unlinked HIV sero-prevalence amongst women attending antenatal care (ANC first visits in six clinics (January to May 2005. Both surveillance systems were conducted as part of the Africa Centre Demographic Information System. Results Population-based HIV prevalence estimates for all women (25.2% and pregnant women (23.7% were significantly lower than that for ANC attendees (37.7%. A large proportion of women attending urban or peri-urban clinics would be predicted to be resident within rural areas. Although overall estimates remained significantly different, presenting and standardising estimates by age and location (clinic for ANC-based estimates and individual-residence for population-based estimates made some group-specific estimates from the two surveillance systems more predictive of one another. Conclusion It is likely that where ANC coverage and contraceptive use is widespread and fertility is low, population-based surveillance under-estimates HIV prevalence due to unrepresentative testing by age, residence and also probably by HIV status, and that ANC sentinel surveillance over

  3. HIV rapid diagnostic testing by lay providers in a key population-led health service programme in Thailand.

    Science.gov (United States)

    Wongkanya, Rapeeporn; Pankam, Tippawan; Wolf, Shauna; Pattanachaiwit, Supanit; Jantarapakde, Jureeporn; Pengnongyang, Supabhorn; Thapwong, Prasopsuk; Udomjirasirichot, Apichat; Churattanakraisri, Yutthana; Prawepray, Nanthika; Paksornsit, Apiluk; Sitthipau, Thidadaow; Petchaithong, Sarayut; Jitsakulchaidejt, Raruay; Nookhai, Somboon; Lertpiriyasuwat, Cheewanan; Ongwandee, Sumet; Phanuphak, Praphan; Phanuphak, Nittaya

    2018-01-01

    Introduction:  Rapid diagnostic testing (RDT) for HIV has a quick turn-around time, which increases the proportion of people testing who receive their result. HIV RDT in Thailand has traditionally been performed only by medical technologists (MTs), which is a barrier to its being scaled up. We evaluated the performance of HIV RDT conducted by trained lay providers who were members of, or worked closely with, a group of men who have sex with men (MSM) and with transgender women (TG) communities, and compared it to tests conducted by MTs. Methods:  Lay providers received a 3-day intensive training course on how to perform a finger-prick blood collection and an HIV RDT as part of the Key Population-led Health Services (KPLHS) programme among MSM and TG. All the samples were tested by lay providers using Alere Determine HIV 1/2. HIV-reactive samples were confirmed by DoubleCheckGold Ultra HIV 1&2 and SD Bioline HIV 1/2. All HIV-positive and 10% of HIV-negative samples were re-tested by MTs using Serodia HIV 1/2. Results:  Of 1680 finger-prick blood samples collected and tested using HIV RDT by lay providers in six drop-in centres in Bangkok, Chiang Mai, Chonburi and Songkhla, 252 (15%) were HIV-positive. MTs re-tested these HIV-positive samples and 143 randomly selected HIV-negative samples with 100% concordant test results. Conclusion:  Lay providers in Thailand can be trained and empowered to perform HIV RDT as they were found to achieve comparable results in sample testing with MTs. Based on the task-shifting concept, this rapid HIV testing performed by lay providers as part of the KPLHS programme has great potential to enhance HIV prevention and treatment programmes among key at-risk populations.

  4. Ischemic heart disease in HIV-infected and HIV-uninfected individuals: a population-based cohort study

    DEFF Research Database (Denmark)

    Obel, N; Thomsen, Henrik F.; Kronborg, G

    2007-01-01

    BACKGROUND: There are concerns about highly active antiretroviral therapy (HAART) causing a progressive increase in the risk of ischemic heart disease. We examined this issue in a nationwide cohort study of patients with human immunodeficiency virus (HIV) infection and a population-based control...... group. METHODS: We determined the rate of first hospitalization for ischemic heart disease in all Danish patients with HIV infection (3953 patients) from 1 January 1995 through 31 December 2004 and compared this rate with that for 373,856 subjects in a population-based control group. Data on first...... hospitalization for ischemic heart disease and comorbidity were obtained from the Danish National Hospital Registry for all study participants. We used Cox's regression to compute the hospitalization rate ratio as an estimate of relative risk, adjusting for comorbidity. RESULTS: Although the difference...

  5. Oral yeast carriage in HIV-infected and non-infected populations in Rosario, Argentina.

    Science.gov (United States)

    Luque, A G; Biasoli, M S; Tosello, M E; Binolfi, A; Lupo, S; Magaró, H M

    2009-01-01

    The objectives of the present study were: (i) to assess the frequency of oral colonisation by Candida species in HIV-positive patients and to compare it with a population of HIV-negative individuals, (ii) to determine the prevalence of C. dubliniensis in both populations and (iii) to determine the susceptibility of C. dubliniensis and other Candida species isolated from HIV-positive patients to the most commonly used antifungal agents. Oral samples were obtained from 101 HIV-positive and 108 HIV-negative subjects. For yeast identification, we used morphology in cornmeal agar, the API 20C Aux, growth at 45 degrees C, d-xylose assimilation, morphology in sunflower seed agar and PCR. The frequency of isolation of Candida in HIV-positive patients was: C. albicans, 60.7%; C. dubliniensis, 20.2%; C. glabrata, 5.6%; C. krusei, 5.6%; C. tropicalis, 4.5%; others, <5%. The frequency of isolation of Candida in HIV-negative patients was: C. albicans, 73.9%; C. tropicalis, 15.5%; C. dubliniensis, 2.1%; C. glabrata, 2.1%; C. parapsilosis, 2.1%; others, <5%. The oral colonisation by yeast in the HIV-positive patients was higher than that in the HIV-negative subjects. The susceptibilities of 42 Candida isolates to three antifungal agents were determined. All isolates of C. dubliniensis were susceptible to fluconazole, although several individuals had been previously treated with this drug. Out of the 42 Candida isolates, 10 presented resistance to fluconazole and 10 to itraconazole. The presence of Candida species, resistant to commonly used antifungal agents, represents a potential risk in immunocompromised patients.

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

    Science.gov (United States)

    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.

  7. Projected demographic composition of the United States population of people living with diagnosed HIV.

    Science.gov (United States)

    Hood, Julia E; Golden, Matthew R; Hughes, James P; Goodreau, Steven M; Siddiqi, Azfar-E-Alam; Buskin, Susan E; Hawes, Stephen E

    2017-12-01

    The transformation of HIV from a fatal disease to lifelong disease has resulted in an HIV-infected population that is growing and aging, placing new and increasing demands on public programs and health services. We used National HIV Surveillance System and US census data to project the demographic composition of the population of people living with diagnosed HIV (PLWDH) in the United States through 2045. The input parameters for the projections include: (1) census projections, (2) number of people with an existing HIV diagnosis in 2013, (3) number of new HIV diagnoses in 2013, and (4) death rate within the PLWDH population in 2013. Sex-, risk group-, and race-specific projections were estimated through an adapted Leslie Matrix Model for age-structured populations. Projections for 2013-2045 suggest that the number of PLWDH in the U.S. will consistently grow, from 917,294 to 1,232,054, though the annual growth rate will slow from 1.8% to 0.8%. The number of PLWDH aged 55 years and older will increase from 232,113 to 470,221. The number of non-Hispanic (NH) African Americans/Blacks and Hispanics is projected to consistently grow, shifting the racial/ethnic composition of the US PLWDH population from 32 to 23% NH-White, 42 to 38% NH-Black, and 20-32% Hispanic between 2013 and 2045. Given current trends, the composition of the PLWDH population is projected to change considerably. Public health practitioners should anticipate large shifts in the age and racial/ethnic structure of the PLWDH population in the United States.

  8. HIV / AIDS in China: migrant population, drug injection responsible for increased transmission.

    Science.gov (United States)

    Thomas, J

    1998-01-01

    By 2000, China will have 1.2 million people infected with HIV and 33,000 people with AIDS. While HIV infection has been reported from almost all provinces and occupational groups in the country, HIV prevalence is highest among IV drug users in Yunnan province. The major source of infection elsewhere in China is through the receipt of tainted blood products and heterosexual intercourse. A National AIDS Committee was formed in October 1986 to advise the government on AIDS policy, and since 1990 to coordinate all AIDS prevention activities. The National Strategies Plan for AIDS/STD Prevention in China during 1996-2000 was prepared in 1995. China's in-country migrant labor population may become the most vulnerable to HIV infection. There are currently about 120 million migrant workers in China, of whom about half are registered, nonpermanent residents working in the fastest developing regions. The open nature of China's economy relative to recent past decades has made it difficult to monitor and control internal migration. Floating populations are the most difficult to reach with preventive health education and they tend to be deprived of access of health care. 61.4% of the migrant population is male and 40% are aged 20-24 years. China's traditional trade routes may be a factor in HIV infection. HIV/AIDS epidemiology, the synergy of STDs and AIDS in China, the international partnership in HIV/AIDS prevention in China, the role of international nongovernmental organizations in China, Hong Kong's contribution to AIDS prevention in China, awareness of the problems associated with HIV infection in China, and the challenges for AIDS-related work in China are discussed.

  9. Evidence of at Least Two Introductions of HIV-1 in the Amerindian Warao Population from Venezuela

    Science.gov (United States)

    Rangel, Héctor R.; Maes, Mailis; Villalba, Julian; Sulbarán, Yoneira; de Waard, Jacobus H.; Bello, Gonzalo; Pujol, Flor H.

    2012-01-01

    Background The Venezuelan Amerindians were, until recently, free of human immunodeficiency virus (HIV) infection. However, in 2007, HIV-1 infection was detected for the first time in the Warao Amerindian population living in the Eastern part of Venezuela, in the delta of the Orinoco river. The aim of this study was to analyze the genetic diversity of the HIV-1 circulating in this population. Methodology/Principal Findings The pol genomic region was sequenced for 16 HIV-1 isolates and for some of them, sequences from env, vif and nef genomic regions were obtained. All HIV-1 isolates were classified as subtype B, with exception of one that was classified as subtype C. The 15 subtype B isolates exhibited a high degree of genetic similarity and formed a highly supported monophyletic cluster in each genomic region analyzed. Evolutionary analyses of the pol genomic region indicated that the date of the most recent common ancestor of the Waraos subtype B clade dates back to the late 1990s. Conclusions/Significance At least two independent introductions of HIV-1 have occurred in the Warao Amerindians from Venezuela. The HIV-1 subtype B was successfully established and got disseminated in the community, while no evidence of local dissemination of the HIV-1 subtype C was detected in this study. These results warrant further surveys to evaluate the burden of this disease, which can be particularly devastating in this Amerindian population, with a high prevalence of tuberculosis, hepatitis B, among other infectious diseases, and with limited access to primary health care. PMID:22808212

  10. The Genomic Signature of Population Reconnection Following Isolation: From Theory to HIV

    Directory of Open Access Journals (Sweden)

    Nicolas Alcala

    2016-01-01

    Full Text Available Ease of worldwide travel provides increased opportunities for organisms not only to colonize new environments but also to encounter related but diverged populations. Such events of reconnection and secondary contact of previously isolated populations are widely observed at different time scales. For example, during the quaternary glaciation, sea water level fluctuations caused temporal isolation of populations, often to be followed by secondary contact. At shorter time scales, population isolation and reconnection of viruses are commonly observed, and such events are often associated with epidemics and pandemics. Here, using coalescent theory and simulations, we describe the temporal impact of population reconnection after isolation on nucleotide differences and the site frequency spectrum, as well as common summary statistics of DNA variation. We identify robust genomic signatures of population reconnection after isolation. We utilize our development to infer the recent evolutionary history of human immunodeficiency virus 1 (HIV-1 in Asia and South America, successfully retrieving the successive HIV subtype colonization events in these regions. Our analysis reveals that divergent HIV-1 subtype populations are currently admixing in these regions, suggesting that HIV-1 may be undergoing a process of homogenization, contrary to popular belief.

  11. Local extinction and recolonization, species effective population size, and modern human origins.

    Science.gov (United States)

    Eller, Elise; Hawks, John; Relethford, John H

    2004-10-01

    A primary objection from a population genetics perspective to a multiregional model of modern human origins is that the model posits a large census size, whereas genetic data suggest a small effective population size. The relationship between census size and effective size is complex, but arguments based on an island model of migration show that if the effective population size reflects the number of breeding individuals and the effects of population subdivision, then an effective population size of 10,000 is inconsistent with the census size of 500,000 to 1,000,000 that has been suggested by archeological evidence. However, these models have ignored the effects of population extinction and recolonization, which increase the expected variance among demes and reduce the inbreeding effective population size. Using models developed for population extinction and recolonization, we show that a large census size consistent with the multiregional model can be reconciled with an effective population size of 10,000, but genetic variation among demes must be high, reflecting low interdeme migration rates and a colonization process that involves a small number of colonists or kin-structured colonization. Ethnographic and archeological evidence is insufficient to determine whether such demographic conditions existed among Pleistocene human populations, and further work needs to be done. More realistic models that incorporate isolation by distance and heterogeneity in extinction rates and effective deme sizes also need to be developed. However, if true, a process of population extinction and recolonization has interesting implications for human demographic history.

  12. Estimating the HIV undiagnosed population in Catalonia, Spain: descriptive and comparative data analysis to identify differences in MSM stratified by migrant and Spanish-born population

    Science.gov (United States)

    Campbell, Colin N J; Vives, Núria; Esteve, Anna; Ambrosioni, Juan; Tural, Cristina; Ferrer, Elena; Navarro, Gemma; Force, Lluis; García, Isabel; Masabeu, Àngels; Vilaró, Josep M; García de Olalla, Patricia; Caylà, Joan Artur; Miró, Josep M; Casabona, Jordi

    2018-01-01

    Objective Undiagnosed HIV continues to be a hindrance to efforts aimed at reducing incidence of HIV. The objective of this study was to provide an estimate of the HIV undiagnosed population in Catalonia and compare the HIV care cascade with this step included between high-risk populations. Methods To estimate HIV incidence, time between infection and diagnosis and the undiagnosed population stratified by CD4 count, we used the ECDC HIV Modelling Tool V.1.2.2. This model uses data on new HIV and AIDS diagnoses from the Catalan HIV/AIDS surveillance system from 2001 to 2013. Data used to estimate the proportion of people enrolled, on ART and virally suppressed in the HIV care cascade were derived from the PISCIS cohort. Results The total number of people living with HIV (PLHIV) in Catalonia in 2013 was 34 729 (32 740 to 36 827), with 12.3% (11.8 to 18.1) of whom were undiagnosed. By 2013, there were 8458 (8101 to 9079) Spanish-born men who have sex with men (MSM) and 2538 (2334 to 2918) migrant MSM living with HIV in Catalonia. A greater proportion of migrant MSM than local MSM was undiagnosed (32% vs 22%). In the subsequent steps of the HIV care cascade, migrants MSM experience greater losses than the Spanish-born MSM: in retention in care (74% vs 55%), in the proportion on combination antiretroviral treatment (70% vs 50%) and virally suppressed (65% vs 46%). Conclusions By the end of 2013, there were an estimated 34 729 PLHIV in Catalonia, of whom 4271 were still undiagnosed. This study shows that the Catalan epidemic of HIV has continued to expand with the key group sustaining HIV transmission being MSM living with undiagnosed HIV. PMID:29490955

  13. Estimating the HIV undiagnosed population in Catalonia, Spain: descriptive and comparative data analysis to identify differences in MSM stratified by migrant and Spanish-born population.

    Science.gov (United States)

    Reyes-Urueña, Juliana Maria; Campbell, Colin N J; Vives, Núria; Esteve, Anna; Ambrosioni, Juan; Tural, Cristina; Ferrer, Elena; Navarro, Gemma; Force, Lluis; García, Isabel; Masabeu, Àngels; Vilaró, Josep M; García de Olalla, Patricia; Caylà, Joan Artur; Miró, Josep M; Casabona, Jordi

    2018-02-28

    Undiagnosed HIV continues to be a hindrance to efforts aimed at reducing incidence of HIV. The objective of this study was to provide an estimate of the HIV undiagnosed population in Catalonia and compare the HIV care cascade with this step included between high-risk populations. To estimate HIV incidence, time between infection and diagnosis and the undiagnosed population stratified by CD4 count, we used the ECDC HIV Modelling Tool V.1.2.2. This model uses data on new HIV and AIDS diagnoses from the Catalan HIV/AIDS surveillance system from 2001 to 2013. Data used to estimate the proportion of people enrolled, on ART and virally suppressed in the HIV care cascade were derived from the PISCIS cohort. The total number of people living with HIV (PLHIV) in Catalonia in 2013 was 34 729 (32 740 to 36 827), with 12.3% (11.8 to 18.1) of whom were undiagnosed. By 2013, there were 8458 (8101 to 9079) Spanish-born men who have sex with men (MSM) and 2538 (2334 to 2918) migrant MSM living with HIV in Catalonia. A greater proportion of migrant MSM than local MSM was undiagnosed (32% vs 22%). In the subsequent steps of the HIV care cascade, migrants MSM experience greater losses than the Spanish-born MSM: in retention in care (74% vs 55%), in the proportion on combination antiretroviral treatment (70% vs 50%) and virally suppressed (65% vs 46%). By the end of 2013, there were an estimated 34 729 PLHIV in Catalonia, of whom 4271 were still undiagnosed. This study shows that the Catalan epidemic of HIV has continued to expand with the key group sustaining HIV transmission being MSM living with undiagnosed HIV. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  14. Population genetic structure, linkage disequilibrium and effective population size of conserved and extensively raised village chicken populations of Southern Africa

    Directory of Open Access Journals (Sweden)

    Khulekhani Sedwell Khanyile

    2015-02-01

    Full Text Available Extensively raised village chickens are considered a valuable source of biodiversity, with genetic variability developed over thousands of years that ought to be characterised and utilized. Surveys that can reveal a population’s genetic structure and provide an insight into its demographic history will give valuable information to manage and conserve important indigenous animal genetic resources. This study reports population diversity and structure, linkage disequilibrium and effective population sizes of Southern African village chickens and conservation flocks from South Africa. DNA samples from 312 chickens from South African village and conservation flocks (n =146, Malawi (n =30 and Zimbabwe (n =136 were genotyped using the Illumina iSelect chicken SNP60K BeadChip. Population genetic structure analysis distinguished the four conservation flocks from the village chicken populations. Of the four flocks, the Ovambo clustered closer to the village chickens particularly those sampled from South Africa. Clustering of the village chickens followed a geographic gradient whereby South African chickens were closer to those from Zimbabwe than to chickens from Malawi. Different conservation flocks seemed to have maintained different components of the ancestral genomes with a higher proportion of village chicken diversity found in the Ovambo population. Overall population LD averaged over chromosomes ranged from 0.03 ± 0.07 to 0.58 ± 0.41 and averaged 0.15 ± 0.16. Higher LD, ranging from 0.29-0.36, was observed between SNP markers that were less than 10kb apart in the conservation flocks. LD in the conservation flocks steadily decreased to 0.15 (PK and 0.24 (VD at SNP marker interval of 500kb. Genomewide LD decay in the village chickens from Malawi, Zimbabwe and South Africa followed a similar trend as the conservation flocks although the mean LD values for the investigated SNP intervals were lower. The results suggest low effective population

  15. The Network for Analysing Longitudinal Population-based HIV/AIDS data on Africa (ALPHA): Data on mortality, by HIV status and stage on the HIV care continuum, among the general population in seven longitudinal studies between 1989 and 2014.

    Science.gov (United States)

    Slaymaker, Emma; McLean, Estelle; Wringe, Alison; Calvert, Clara; Marston, Milly; Reniers, Georges; Kabudula, Chodziwadziwa Whiteson; Crampin, Amelia; Price, Alison; Michael, Denna; Urassa, Mark; Kwaro, Daniel; Sewe, Maquins; Eaton, Jeffrey W; Rhead, Rebecca; Nakiyingi-Miiro, Jessica; Lutalo, Tom; Nabukalu, Dorean; Herbst, Kobus; Hosegood, Victoria; Zaba, Basia

    2017-11-06

    Timely progression of people living with HIV (PLHIV) from the point of infection through the pathway from diagnosis to treatment is important in ensuring effective care and treatment of HIV and preventing HIV-related deaths and onwards transmission of infection.  Reliable, population-based estimates of new infections are difficult to obtain for the generalised epidemics in sub-Saharan Africa.  Mortality data indicate disease burden and, if disaggregated along the continuum from diagnosis to treatment, can also reflect the coverage and quality of different HIV services.  Neither routine statistics nor observational clinical studies can estimate mortality prior to linkage to care nor following disengagement from care.  For this, population-based data are required. The Network for Analysing Longitudinal Population-based HIV/AIDS data on Africa brings together studies in Kenya, Malawi, South Africa, Tanzania, Uganda, and Zimbabwe.  Eight studies have the necessary data to estimate mortality by HIV status, and seven can estimate mortality at different stages of the HIV care continuum.  This data note describes a harmonised dataset containing anonymised individual-level information on survival by HIV status for adults aged 15 and above. Among PLHIV, the dataset provides information on survival during different periods: prior to diagnosis of infection; following diagnosis but before linkage to care; in pre-antiretroviral treatment (ART) care; in the first six months after ART initiation; among people continuously on ART for 6+ months; and among people who have ever interrupted ART.

  16. HIV-infected mental health patients: characteristics and comparison with HIV-infected patients from the general population and non-infected mental health patients

    Directory of Open Access Journals (Sweden)

    Schadé Annemiek

    2013-01-01

    Full Text Available Abstract Objectives HIV-infected patients are at increased risk of developing mental health symptoms, which negatively influence the treatment of the HIV-infection. Mental health problems in HIV-infected patients may affect public health. Psychopathology, including depression and substance abuse, can increase hazardous sexual behaviour and, with it, the chance of spreading HIV. Therefore, it is important to develop an optimal treatment plan for HIV-infected patients with mental health problems. The majority of HIV-infected patients in the Netherlands (almost 60% are homosexual men. The main objectives of this study were to describe the clinical and demographic characteristics of patients with HIV who seek treatment for their mental health symptoms in the Netherlands. Secondly, we tested whether HIV infected and non-infected homosexual patients with a lifetime depressive disorder differed on several mental health symptoms. Methods We compared a cohort of 196 patients who visited the outpatient clinic for HIV and Mental Health with HIV-infected patients in the general population in Amsterdam (ATHENA-study and with non-HIV infected mental health patients (NESDA-study. DSM-IV diagnoses were determined, and several self-report questionnaires were used to assess mental health symptoms. Results Depressive disorders were the most commonly occurring diagnoses in the cohort and frequent drug use was common. HIV-infected homosexual men with a depressive disorder showed no difference in depressive symptoms or sleep disturbance, compared with non-infected depressive men. However, HIV-positive patients did express more symptoms like fear, anger and guilt. Although they showed significantly more suicidal ideation, suicide attempts were not more prevalent among HIV-infected patients. Finally, the HIV-infected depressive patients displayed a considerably higher level of drug use than the HIV-negative group. Conclusion Habitual drug use is a risk factor for

  17. Body size distributions of the pale grass blue butterfly in Japan: Size rules and the status of the Fukushima population

    Science.gov (United States)

    Taira, Wataru; Iwasaki, Mayo; Otaki, Joji M.

    2015-01-01

    The body size of the pale grass blue butterfly, Zizeeria maha, has been used as an environmental indicator of radioactive pollution caused by the Fukushima nuclear accident. However, geographical and temporal size distributions in Japan and temperature effects on size have not been established in this species. Here, we examined the geographical, temporal, and temperature-dependent changes of the forewing size of Z. maha argia in Japan. Butterflies collected in 2012 and 2013 from multiple prefectures throughout Japan demonstrated an inverse relationship of latitude and forewing size, which is the reverse of Bergmann’s cline. The Fukushima population was significantly larger than the Aomori and Miyagi populations and exhibited no difference from most of the other prefectural populations. When monitored at a single geographic locality every other month, forewing sizes were the largest in April and the smallest in August. Rearing larvae at a constant temperature demonstrated that forewing size followed the temperature-size rule. Therefore, the converse Bergmann’s rule and the temperature-size rule coexist in this multivoltine species. Our study establishes this species as a useful environmental indicator and supports the idea that the size reduction observed only in Fukushima Prefecture in 2011 was caused by the environmental stress of radioactive pollution. PMID:26197998

  18. Both population size and patch quality affect local extinctions and colonizations

    OpenAIRE

    Franzén, Markus; Nilsson, Sven G.

    2009-01-01

    Currently, the habitat of many species is fragmented, resulting in small local populations with individuals occasionally dispersing between the remaining habitat patches. In a solitary bee metapopulation, extinction probability was related to both local bee population sizes and pollen resources measured as host plant population size. Patch size, on the other hand, had no additional predictive power. The turnover rate of local bee populations in 63 habitat patches over 4 years was high, with 7...

  19. Sexual Behaviors and HIV Status: A Population-Based Study Among Older Adults in Rural South Africa

    Science.gov (United States)

    Gómez-Olivé, Francesc X.; Rohr, Julia K.; Houle, Brian C.; Kabudula, Chodziwadziwa W.; Wagner, Ryan G.; Salomon, Joshua A.; Kahn, Kathleen; Berkman, Lisa F.; Tollman, Stephen M.; Bärnighausen, Till

    2017-01-01

    Objective: To identify the unmet needs for HIV prevention among older adults in rural South Africa. Methods: We analyzed data from a population-based sample of 5059 men and women aged 40 years and older from the study Health and Aging in Africa: Longitudinal Studies of INDEPTH Communities (HAALSI), which was carried out in the Agincourt health and sociodemographic surveillance system in the Mpumalanga province of South Africa. We estimated the prevalence of HIV (laboratory-confirmed and self-reported) and key sexual behaviors by age and sex. We compared sexual behavior profiles across HIV status categories with and without age–sex standardization. Results: HIV prevalence was very high among HAALSI participants (23%, 95% confidence interval [CI]: 21 to 24), with no sex differences. Recent sexual activity was common (56%, 95% CI: 55 to 58) across all HIV status categories. Condom use was low among HIV-negative adults (15%, 95% CI: 14 to 17), higher among HIV-positive adults who were unaware of their HIV status (27%, 95% CI: 22 to 33), and dramatically higher among HIV-positive adults who were aware of their status (75%, 95% CI: 70 to 80). Casual sex and multiple partnerships were reported at moderate levels, with slightly higher estimates among HIV-positive compared to HIV-negative adults. Differences by HIV status remained after age–sex standardization. Conclusions: Older HIV-positive adults in an HIV hyperendemic community of rural South Africa report sexual behaviors consistent with high HIV transmission risk. Older HIV-negative adults report sexual behaviors consistent with high HIV acquisition risk. Prevention initiatives tailored to the particular prevention needs of older adults are urgently needed to reduce HIV risk in this and similar communities in sub-Saharan Africa. PMID:27926667

  20. Sexual Behaviors and HIV Status: A Population-Based Study Among Older Adults in Rural South Africa.

    Science.gov (United States)

    Rosenberg, Molly S; Gómez-Olivé, Francesc X; Rohr, Julia K; Houle, Brian C; Kabudula, Chodziwadziwa W; Wagner, Ryan G; Salomon, Joshua A; Kahn, Kathleen; Berkman, Lisa F; Tollman, Stephen M; Bärnighausen, Till

    2017-01-01

    To identify the unmet needs for HIV prevention among older adults in rural South Africa. We analyzed data from a population-based sample of 5059 men and women aged 40 years and older from the study Health and Aging in Africa: Longitudinal Studies of INDEPTH Communities (HAALSI), which was carried out in the Agincourt health and sociodemographic surveillance system in the Mpumalanga province of South Africa. We estimated the prevalence of HIV (laboratory-confirmed and self-reported) and key sexual behaviors by age and sex. We compared sexual behavior profiles across HIV status categories with and without age-sex standardization. HIV prevalence was very high among HAALSI participants (23%, 95% confidence interval [CI]: 21 to 24), with no sex differences. Recent sexual activity was common (56%, 95% CI: 55 to 58) across all HIV status categories. Condom use was low among HIV-negative adults (15%, 95% CI: 14 to 17), higher among HIV-positive adults who were unaware of their HIV status (27%, 95% CI: 22 to 33), and dramatically higher among HIV-positive adults who were aware of their status (75%, 95% CI: 70 to 80). Casual sex and multiple partnerships were reported at moderate levels, with slightly higher estimates among HIV-positive compared to HIV-negative adults. Differences by HIV status remained after age-sex standardization. Older HIV-positive adults in an HIV hyperendemic community of rural South Africa report sexual behaviors consistent with high HIV transmission risk. Older HIV-negative adults report sexual behaviors consistent with high HIV acquisition risk. Prevention initiatives tailored to the particular prevention needs of older adults are urgently needed to reduce HIV risk in this and similar communities in sub-Saharan Africa.

  1. Founding population size of an aquatic invasive species

    Science.gov (United States)

    Kalinowski, Steven T.; Muhlfeld, Clint C.; Guy, Christopher S.; Benjamin Cox,

    2010-01-01

    Non-native species of fish threaten native fishes throughout North America, and in the Rocky Mountains, introduced populations of lake trout threaten native populations of bull trout. Effective management of lake trout and other exotic species require understanding the dynamics of invasion in order to either suppress non-native populations or to prevent their spread. In this study, we used microsatellite genetic data to estimate the number of lake trout that invaded a population of bull trout in Swan Lake, MT. Examination of genetic diversity and allele frequencies within the Swan Lake populations showed that most of the genes in the lake trout population are descended from two founders. This emphasizes the importance of preventing even a few lake trout from colonizing new territory.

  2. Change in genetic size of small-closed populations: Lessons from a domestic mammal population.

    Science.gov (United States)

    Ghafouri-Kesbi, Farhad

    2010-10-01

    The aim of this study was to monitor changes in genetic size of a small-closed population of Iranian Zandi sheep, by using pedigree information from animals born between 1991 and 2005. The genetic size was assessed by using measures based on the probability of identity-by-descend of genes (coancestry, f, and effective population size, N(e) ), as well as measures based on probability of gene origin (effective number of founders, f(e) , effective number of founder genomes, f(g) , and effective number of non-founder genomes, f(ne) ). Average coancestry, or the degree of genetic similarity of individuals, increased from 0.81% to 1.44% during the period 1993 to 2005, at the same time that N(e) decreased from 263 to 93. The observed trend for f(e) was irregular throughout the experiment in a way that f(e) was 68, 87, 77, 92, and 80 in 1993, 1996, 1999, 2002, and 2005, respectively. Simultaneously, f(g) , the most informative effective number, decreased from 61 to 35. The index of genetic diversity (GD) which was obtained from estimates of f(g) , decreased about 2% throughout the period studied. In addition, a noticeable reduction was observed in the estimates of f(ne) from 595 in 1993 to 61 in 2005. The higher than 1 ratio of f(e) to f(g) indicated the presence of bottlenecks and genetic drift in the development of this population of Zandi sheep. From 1993 to 1999, f(ne) was much higher than f(e) , thereby indicating that with respect to loss of genetic diversity, the unequal contribution of founders was more important than the random genetic drift in non-founder generations. Subsequently, random genetic drift in non-founder generations was the major reason for f(e) > f(ne) . The minimization of average coancestry in new reproductive individuals was recommended as a means of preserving the population against a further loss in genetic diversity.

  3. One size does not fit all: HIV testing preferences differ among high-risk groups in Northern Tanzania.

    Science.gov (United States)

    Ostermann, Jan; Njau, Bernard; Mtuy, Tara; Brown, Derek S; Mühlbacher, Axel; Thielman, Nathan

    2015-01-01

    In order to maximize the effectiveness of "Seek, Test, and Treat" strategies for curbing the HIV epidemic, new approaches are needed to increase the uptake of HIV testing services, particularly among high-risk groups. Low HIV testing rates among such groups suggest that current testing services may not align well with the testing preferences of these populations. Female bar workers and male mountain porters have been identified as two important high-risk groups in the Kilimanjaro Region of Tanzania. We used conventional survey methods and a discrete choice experiment (DCE), a preference elicitation method increasingly applied by economists and policy-makers to inform health policy and services, to analyze trade-offs made by individuals and quantify preferences for HIV testing services. Bivariate descriptive statistics were used to analyze differences in survey responses across groups. Compared to 486 randomly selected community members, 162 female bar workers and 194 male Kilimanjaro porters reported 2-3 times as many lifetime sexual partners (p porters preferred testing in venues where antiretroviral therapy was readily available. Both high-risk groups were less averse to traveling longer distances to test compared to their community counterparts. These results expose systematic differences in HIV testing preferences across high-risk populations compared to their community peers. Tailoring testing options to the preferences of high-risk populations should be evaluated as a means of improving uptake of testing in these populations.

  4. Monitoring HIV Prevention Programme Outcomes among Key Populations in Kenya: Findings from a National Survey.

    Directory of Open Access Journals (Sweden)

    Parinita Bhattacharjee

    Full Text Available In preparation for the implementation of the Kenya AIDS Strategic Framework 2014/15-2018/19, the Kenya National AIDS and STI Control Programme facilitated a national polling booth survey as part of a baseline assessment of HIV-related risk behaviours among FSWs, MSM, and PWID, and their utilization of existing preventive interventions, as well as structural factors that may influence KPs' vulnerability to HIV. The survey was conducted among "key populations" (female sex workers, men who have sex with men, and people who inject drugs to understand current HIV risk and prevention behaviours, utilization of existing programmes and services, and experiences of violence. In total, 3,448 female sex workers, 1,308 men who have sex with men, and 690 people who inject drugs were randomly selected to participate in polling booth survey sessions from seven priority sites. Survey responses were aggregated and descriptive statistics derived. In general, reported condom use among all key populations was quite high with paying clients, and lower with regular, non-paying partners. Many participants reported unavailability of condoms or clean injecting equipment within the past month. Exposure to, and utilization of, existing HIV prevention services varied significantly among the groups, and was reported least commonly by female sex workers. Encouragingly, approximately three-quarters of all key population members reported receiving an HIV test in the past three months. All key population groups reported experiencing high levels of physical and sexual violence from partners/clients, and/or arrest and violence by law enforcement officials. Although some of the findings are encouraging, there is room for improvement in HIV prevention programmes and services for key populations across Kenya.

  5. Masculine sex ratios, population age structure and the potential spread of HIV in China

    Directory of Open Access Journals (Sweden)

    M. Giovanna Merli

    2010-01-01

    Full Text Available There is much speculation regarding the contribution of China's changing demography to the spread of HIV/AIDS. We employ a bio-behavioral macrosimulation model of the heterosexual spread of HIV/AIDS to evaluate the roles that China's unique demographic conditions -- (1 masculine sex ratios at birth and (2 a population age structure that reflects rapid fertility decline since the 1970's -- play in altering the market for sexual partners, thereby potentially fueling an increase in behaviors associated with greater risk of HIV infection. We first simulate the relative contributions of the sex ratio at birth and the population age structure to the oversupply of males in the market for sexual partners and show that the sex ratio at birth only aggravates the severe oversupply of males which is primarily a consequence of the population age structure. We then examine the potential consequences of this demographic distortion for the spread of HIV infection and show that, to the extent that males adapt to the dearth of suitable female partners by seeking unprotected sexual contacts with female sex workers, the impact of the oversupply of males in the sexual partnership market on the spread of HIV will be severe.

  6. Evaluating HIV prevention strategies for populations in key affected groups: The example of Cabo Verde

    Science.gov (United States)

    Monteiro, João Filipe G.; Galea, Sandro; Flanigan, Timothy; Monteiro, Maria de Lourdes; Friedman, Samuel R.; Marshall, Brandon DL

    2015-01-01

    Objectives We used an individual-based model to evaluate the effects of hypothetical prevention interventions on HIV incidence trajectories in a concentrated, mixed epidemic setting from 2011 to 2021, and using Cabo Verde as an example. Methods Simulations were conducted to evaluate the extent to which early HIV treatment and optimization of care, HIV testing, condom distribution, and substance abuse treatment could eliminate new infections (i.e., reduce incidence to less than 10 cases per 10,000 person-years) among non-drug users, female sex workers (FSW), and people who use drugs (PWUD). Results Scaling up all four interventions resulted in the largest decreases in HIV, with estimates ranging from 1.4 (95%CI:1.36–1.44) per 10,000 person-years among non-drug users to 8.2 (95%CI:7.8–8.6) per 10,000 person-years among PWUD in 2021. Intervention scenarios targeting FWS and PWUD also resulted in HIV incidence estimates at or below 10 per 10,000 person-years by 2021 for all population sub-groups. Conclusions Our results suggest that scaling up multiple interventions among entire population is necessary to achieve elimination. However, prioritizing key populations with this combination prevention strategy may also result in a substantial decrease in total incidence. PMID:25838121

  7. Evaluating HIV prevention strategies for populations in key affected groups: the example of Cabo Verde.

    Science.gov (United States)

    Monteiro, João Filipe G; Galea, Sandro; Flanigan, Timothy; Monteiro, Maria de Lourdes; Friedman, Samuel R; Marshall, Brandon D L

    2015-05-01

    We used an individual-based model to evaluate the effects of hypothetical prevention interventions on HIV incidence trajectories in a concentrated, mixed epidemic setting from 2011 to 2021, and using Cabo Verde as an example. Simulations were conducted to evaluate the extent to which early HIV treatment and optimization of care, HIV testing, condom distribution, and substance abuse treatment could eliminate new infections (i.e., reduce incidence to less than 10 cases per 10,000 person-years) among non-drug users, female sex workers (FSW), and people who use drugs (PWUD). Scaling up all four interventions resulted in the largest decreases in HIV, with estimates ranging from 1.4 (95 % CI 1.36-1.44) per 10,000 person-years among non-drug users to 8.2 (95 % CI 7.8-8.6) per 10,000 person-years among PWUD in 2021. Intervention scenarios prioritizing FWS and PWUD also resulted in HIV incidence estimates at or below 10 per 10,000 person-years by 2021 for all population sub-groups. Our results suggest that scaling up multiple interventions among entire population is necessary to achieve elimination. However, prioritizing key populations with this combination prevention strategy may also result in a substantial decrease in total incidence.

  8. Stability patterns for a size-structured population model and its stage-structured counterpart

    DEFF Research Database (Denmark)

    Zhang, Lai; Pedersen, Michael; Lin, Zhigui

    2015-01-01

    In this paper we compare a general size-structured population model, where a size-structured consumer feeds upon an unstructured resource, to its simplified stage-structured counterpart in terms of equilibrium stability. Stability of the size-structured model is understood in terms of an equivale...... to the population level....

  9. Improving ethical and participatory practice for marginalized populations in biomedical HIV prevention trials: lessons from Thailand.

    Directory of Open Access Journals (Sweden)

    Dan Allman

    Full Text Available BACKGROUND: This paper presents findings from a qualitative investigation of ethical and participatory issues related to the conduct of biomedical HIV prevention trials among marginalized populations in Thailand. This research was deemed important to conduct, as several large-scale biomedical HIV prevention trials among marginalized populations had closed prematurely in other countries, and a better understanding of how to prevent similar trial closures from occurring in the future was desired. METHODS: In-depth key informant interviews were held in Bangkok and Chiang Mai, Thailand. Interviews were audio recorded, transcribed, translated and thematically analyzed. The Good Participatory Practice Guidelines for Biomedical HIV Prevention Trials (GPP guided this work. RESULTS: Fourteen interviews were conducted: 10 with policymakers, academic and community-based researchers and trial staff and four with representatives of non-governmental organizations (NGOs. Suggested ways to improve ethical and participatory practice centered on standards of HIV prevention, informed consent, communication and human rights. In particular, the need to overcome language and literacy differences was identified. Key informants felt communication was the basis of ethical understanding and trust within biomedical HIV prevention trial contexts, and thus fundamental to trial participants' ability to exercise free will. DISCUSSION: Biomedical HIV prevention trials present opportunities for inclusive and productive ethical and participatory practice. Key informants suggested that efforts to improve practice could result in better relationships between research stakeholders and research investigative teams and by extension, better, more ethical participatory trials. This research took place in Thailand and its findings apply primarily to Thailand. However, given the universality of many ethical considerations, the results of this study can inform the improvement of ethical

  10. Improving ethical and participatory practice for marginalized populations in biomedical HIV prevention trials: lessons from Thailand.

    Science.gov (United States)

    Allman, Dan; Ditmore, Melissa Hope; Kaplan, Karyn

    2014-01-01

    This paper presents findings from a qualitative investigation of ethical and participatory issues related to the conduct of biomedical HIV prevention trials among marginalized populations in Thailand. This research was deemed important to conduct, as several large-scale biomedical HIV prevention trials among marginalized populations had closed prematurely in other countries, and a better understanding of how to prevent similar trial closures from occurring in the future was desired. In-depth key informant interviews were held in Bangkok and Chiang Mai, Thailand. Interviews were audio recorded, transcribed, translated and thematically analyzed. The Good Participatory Practice Guidelines for Biomedical HIV Prevention Trials (GPP) guided this work. Fourteen interviews were conducted: 10 with policymakers, academic and community-based researchers and trial staff and four with representatives of non-governmental organizations (NGOs). Suggested ways to improve ethical and participatory practice centered on standards of HIV prevention, informed consent, communication and human rights. In particular, the need to overcome language and literacy differences was identified. Key informants felt communication was the basis of ethical understanding and trust within biomedical HIV prevention trial contexts, and thus fundamental to trial participants' ability to exercise free will. Biomedical HIV prevention trials present opportunities for inclusive and productive ethical and participatory practice. Key informants suggested that efforts to improve practice could result in better relationships between research stakeholders and research investigative teams and by extension, better, more ethical participatory trials. This research took place in Thailand and its findings apply primarily to Thailand. However, given the universality of many ethical considerations, the results of this study can inform the improvement of ethical and participatory practice in other parts of the world where

  11. The changing HIV-1 genetic characteristics and transmitted drug resistance among recently infected population in Yunnan, China.

    Science.gov (United States)

    Chen, M; Jia, M H; Ma, Y L; Luo, H B; Chen, H C; Yang, C J; Dai, J; Yang, L; Dong, L J; Lu, R; Song, L J; Han, Y; Lu, J Y; Cheung, A K L; Chen, Z W; Lu, L

    2018-04-01

    Multiple human immunodeficiency virus (HIV)-1 genotypes in China were first discovered in Yunnan Province before disseminating throughout the country. As the HIV-1 epidemic continues to expand in Yunnan, genetic characteristics and transmitted drug resistance (TDR) should be further investigated among the recently infected population. Among 2828 HIV-positive samples newly reported in the first quarter of 2014, 347 were identified as recent infections with BED-captured enzyme immunoassay (CEIA). Of them, 291 were successfully genotyped and identified as circulating recombinant form (CRF)08_BC (47.4%), unique recombinant forms (URFs) (18.2%), CRF01_AE (15.8%), CRF07_BC (14.4%), subtype C (2.7%), CRF55_01B (0.7%), subtype B (0.3%) and CRF64_BC (0.3%). CRF08_BC and CRF01_AE were the predominant genotypes among heterosexual and homosexual infections, respectively. CRF08_BC, URFs, CRF01_AE and CRF07_BC expanded with higher prevalence in central and eastern Yunnan. The recent common ancestor of CRF01_AE, CRF07_BC and CRF08_BC dated back to 1983.1, 1992.1 and 1989.5, respectively. The effective population sizes (EPS) for CRF01_AE and CRF07_BC increased exponentially during 1991-1999 and 1994-1999, respectively. The EPS for CRF08_BC underwent two exponential growth phases in 1994-1998 and 2001-2002. Lastly, TDR-associated mutations were identified in 1.8% of individuals. These findings not only enhance our understanding of HIV-1 evolution in Yunnan but also have implications for vaccine design and patient management strategies.

  12. Considerations for a Human Rights Impact Assessment of a Population Wide Treatment for HIV Prevention Intervention.

    Science.gov (United States)

    Hanefeld, Johanna; Bond, Virginia; Seeley, Janet; Lees, Shelley; Desmond, Nicola

    2015-12-01

    Increasing attention is being paid to the potential of anti-retroviral treatment (ART) for HIV prevention. The possibility of eliminating HIV from a population through a universal test and treat intervention, where all people within a population are tested for HIV and all positive people immediately initiated on ART, as part of a wider prevention intervention, was first proposed in 2009. Several clinical trials testing this idea are now in inception phase. An intervention which relies on universally testing the entire population for HIV will pose challenges to human rights, including obtaining genuine consent to testing and treatment. It also requires a context in which people can live free from fear of stigma, discrimination and violence, and can access services they require. These challenges are distinct from the field of medical ethics which has traditionally governed clinical trials and focuses primarily on patient researcher relationship. This paper sets out the potential impact of a population wide treatment as prevention intervention on human rights. It identifies five human right principles of particular relevance: participation, accountability, the right to health, non-discrimination and equality, and consent and confidentiality. The paper proposes that explicit attention to human rights can strengthen a treatment as prevention intervention, contribute to mediating likely health systems challenges and offer insights on how to reach all sections of the population. © 2013 John Wiley & Sons Ltd.

  13. Documenting and explaining the HIV decline in east Zimbabwe: the Manicaland General Population Cohort.

    Science.gov (United States)

    Gregson, Simon; Mugurungi, Owen; Eaton, Jeffrey; Takaruza, Albert; Rhead, Rebecca; Maswera, Rufurwokuda; Mutsvangwa, Junior; Mayini, Justin; Skovdal, Morten; Schaefer, Robin; Hallett, Timothy; Sherr, Lorraine; Munyati, Shungu; Mason, Peter; Campbell, Catherine; Garnett, Geoffrey P; Nyamukapa, Constance Anesu

    2017-10-06

    The Manicaland cohort was established to provide robust scientific data on HIV prevalence and incidence, patterns of sexual risk behaviour and the demographic impact of HIV in a sub-Saharan African population subject to a generalised HIV epidemic. The aims were later broadened to include provision of data on the coverage and effectiveness of national HIV control programmes including antiretroviral therapy (ART). General population open cohort located in 12 sites in Manicaland, east Zimbabwe, representing 4 major socioeconomic strata (small towns, agricultural estates, roadside settlements and subsistence farming areas). 9,109 of 11,453 (79.5%) eligible adults (men 17-54 years; women 15-44 years) were recruited in a phased household census between July 1998 and January 2000. Five rounds of follow-up of the prospective household census and the open cohort were conducted at 2-year or 3-year intervals between July 2001 and November 2013. Follow-up rates among surviving residents ranged between 77.0% (over 3 years) and 96.4% (2 years). HIV prevalence was 25.1% at baseline and had a substantial demographic impact with 10-fold higher mortality in HIV-infected adults than in uninfected adults and a reduction in the growth rate in the worst affected areas (towns) from 2.9% to 1.0%pa. HIV infection rates have been highest in young adults with earlier commencement of sexual activity and in those with older sexual partners and larger numbers of lifetime partners. HIV prevalence has since fallen to 15.8% and HIV incidence has also declined from 2.1% (1998-2003) to 0.63% (2009-2013) largely due to reduced sexual risk behaviour. HIV-associated mortality fell substantially after 2009 with increased availability of ART. We plan to extend the cohort to measure the effects on the epidemic of current and future HIV prevention and treatment programmes. Proposals for access to these data and for collaboration are welcome. © Article author(s) (or their employer(s) unless otherwise

  14. Drug resistance pattern of mycobacterial isolates in HIV and non-HIV population in South India

    Directory of Open Access Journals (Sweden)

    Umamaheshwari Shivaswamy

    2016-01-01

    Full Text Available Background: Emergence of drug resistance has complicated the treatment of tuberculosis (TB. WHO reports India to be one among 27 “high burden” multidrug-resistant (MDR TB countries. Objective: To diagnose TB and detect drug resistance of mycobacterial isolates in acid-fast bacilli (AFB smear negative HIV reactive patients (Group A and compare them with HIV seropositive AFB smear positive (Group B and HIV-seronegative AFB positive cases (Group C. Materials and Methods: Clinical specimens collected in all groups were processed as per the standard protocol except blood, which was processed by lysis centrifugation technique. They were then inoculated with Lowenstein-Jensen media and the isolates obtained were subjected to drug susceptibility test (DST by proportion method and genotype MTBDR plus assay. Results: In Group A, 162 patients were included. Of the 443 clinical samples collected, 76 mycobacterial strains were obtained from 67 (41% patients. Of these, 50 (65.8% were sensitive to all drugs and 26 (34.2% resistant to one or more anti-tubercular drugs. Antibiogram of Group A when compared with Group B and C showed that the MDR rate 6.6%, 6.7% and 8% respectively did not differ much; but resistance to at least single drug was (26 [34.2%], 3 [10%], and 8 [16%], respectively. Conclusion: Our study suggests that HIV has no influence on the anti-tubercular resistance pattern, but increased MDR rate along with HIV in high TB burden setting stresses the need for early diagnosis and DST in providing proper regimens and improve prognosis.

  15. From HIV infection to therapeutic response: a population-based longitudinal HIV cascade-of-care study in KwaZulu-Natal, South Africa.

    Science.gov (United States)

    Haber, Noah; Tanser, Frank; Bor, Jacob; Naidu, Kevindra; Mutevedzi, Tinofa; Herbst, Kobus; Porter, Kholoud; Pillay, Deenan; Bärnighausen, Till

    2017-05-01

    Standard approaches to estimation of losses in the HIV cascade of care are typically cross-sectional and do not include the population stages before linkage to clinical care. We used indiviual-level longitudinal cascade data, transition by transition, including population stages, both to identify the health-system losses in the cascade and to show the differences in inference between standard methods and the longitudinal approach. We used non-parametric survival analysis to estimate a longitudinal HIV care cascade for a large population of people with HIV residing in rural KwaZulu-Natal, South Africa. We linked data from a longitudinal population health surveillance (which is maintained by the Africa Health Research Institute) with patient records from the local public-sector HIV treatment programme (contained in an electronic clinical HIV treatment and care database, ARTemis). We followed up all people who had been newly detected as having HIV between Jan 1, 2006, and Dec 31, 2011, across six cascade stages: three population stages (first positive HIV test, HIV status knowledge, and linkage to care) and three clinical stages (eligibility for antiretroviral therapy [ART], initiation of ART, and therapeutic response). We compared our estimates to cross-sectional cascades in the same population. We estimated the cumulative incidence of reaching a particular cascade stage at a specific time with Kaplan-Meier survival analysis. Our population consisted of 5205 individuals with HIV who were followed up for 24 031 person-years. We recorded 598 deaths. 4539 individuals gained knowledge of their positive HIV status, 2818 were linked to care, 2151 became eligible for ART, 1839 began ART, and 1456 had successful responses to therapy. We used Kaplan-Meier survival analysis to adjust for censorship due to the end of data collection, and found that 8 years after testing positive in the population health surveillance, 16% had died. Among living patients, 82% knew their HIV

  16. Association of knowledge of HIV and other factors with individuals' attitudes toward HIV infection: a national cross-sectional survey among the Japanese non-medical working population.

    Directory of Open Access Journals (Sweden)

    Guoqin Wang

    Full Text Available BACKGROUND: The stigma of and discrimination because of HIV has been described as the most important obstacle to prevention and treatment efforts. The purpose of this study was to investigate negative attitudes and prejudice toward HIV among the Japanese non-medical working population and to explore contributing factors. METHODS: An online anonymous nationwide survey involving approximately 3,000 individuals was conducted in Japan. Questions ranged from background information and HIV knowledge to individuals' attitudes towards HIV infection in the workplace. Descriptive statistics and logistic regression were applied for analysis. RESULTS: Thirty-three percent of participants feared transmission of HIV from infected colleagues, 34% tended to avoid contact with them and 40% had prejudiced opinions about HIV infection. Despite a relatively high level of knowledge of HIV/AIDS overall (11.9 ± 3.3 from 15 points, only 50% of individuals were aware of some issues. Greater knowledge was associated with less negative attitudes towards HIV infection (OR 0.39, 95% CI 0.31-0.48 for prejudiced opinion, high compared with low level of knowledge, whereas greater health consciousness was inversely related to attitude (OR 1.97, 95% CI 1.50-2.58 for prejudiced opinion, high compared with low health consciousness. CONCLUSION: Knowledge neutralizes peoples' negative attitudes towards HIV infection, whereas greater health consciousness may worsen them. Educational programs should balance knowledge with health consciousness to improve the efficacy of HIV interventions.

  17. Migration and risk of HIV acquisition in Rakai, Uganda: a population-based cohort study.

    Science.gov (United States)

    Olawore, Oluwasolape; Tobian, Aaron A R; Kagaayi, Joseph; Bazaale, Jeremiah M; Nantume, Betty; Kigozi, Grace; Nankinga, Justine; Nalugoda, Fred; Nakigozi, Gertrude; Kigozi, Godfrey; Gray, Ronald H; Wawer, Maria J; Ssekubugu, Robert; Santelli, John S; Reynolds, Steven J; Chang, Larry W; Serwadda, David; Grabowski, Mary K

    2018-04-01

    In sub-Saharan Africa, migrants typically have higher HIV prevalence than non-migrants; however, whether HIV acquisition typically precedes or follows migration is unknown. We aimed to investigate the risk of HIV after migration in Rakai District, Uganda. In a prospective population-based cohort of HIV-negative participants aged 15-49 years in Rakai, Uganda, between April 6, 1999, and Jan 30, 2015, we assessed the association between migration and HIV acquisition. Individuals were classified as recent in-migrants (≤2 years in community), non-recent in-migrants (>2 years in community), or permanent residents with no migration history. The primary outcome was incident HIV infection. We used Poisson regression to estimate incidence rate ratios (IRRs) of HIV associated with residence status with adjustment for demographics, sexual behaviours, and time. Data were also stratified and analysed within three periods (1999-2004, 2005-11, and 2011-15) in relation to the introduction of combination HIV prevention (CHP; pre-CHP, early CHP, and late CHP). Among 26 995 HIV-negative people who participated in the Rakai Community Cohort Study survey, 15 187 (56%) contributed one or more follow-up visits (89 292 person-years of follow-up) and were included in our final analysis. 4451 (29%) were ever in-migrants and 10 736 (71%) were permanent residents. 841 incident HIV events occurred, including 243 (29%) among in-migrants. HIV incidence per 100 person-years was significantly increased among recent in-migrants compared with permanent residents, for both women (1·92, 95% CI 1·52-2·43 vs 0·93, 0·84-1·04; IRR adjusted for demographics 1·75, 95% CI 1·33-2·33) and men (1·52, 0·99-2·33 vs 0·84, 0·74-0·94; 1·74, 1·12-2·71), but not among non-recent in-migrants (IRR adjusted for demographics 0·94, 95% CI 0·74-1·19 for women and 1·28, 0·94-1·74 for men). Between the pre-CHP and late-CHP periods, HIV incidence declined among permanent resident men (p

  18. Host-specific adaptation of HIV-1 subtype B in the Japanese population.

    Science.gov (United States)

    Chikata, Takayuki; Carlson, Jonathan M; Tamura, Yoshiko; Borghan, Mohamed Ali; Naruto, Takuya; Hashimoto, Masao; Murakoshi, Hayato; Le, Anh Q; Mallal, Simon; John, Mina; Gatanaga, Hiroyuki; Oka, Shinichi; Brumme, Zabrina L; Takiguchi, Masafumi

    2014-05-01

    The extent to which HIV-1 clade B strains exhibit population-specific adaptations to host HLA alleles remains incompletely known, in part due to incomplete characterization of HLA-associated HIV-1 polymorphisms (HLA-APs) in different global populations. Moreover, it remains unknown to what extent the same HLA alleles may drive significantly different escape pathways across populations. As the Japanese population exhibits distinctive HLA class I allele distributions, comparative analysis of HLA-APs between HIV-1 clade B-infected Japanese and non-Asian cohorts could shed light on these questions. However, HLA-APs remain incompletely mapped in Japan. In a cohort of 430 treatment-naive Japanese with chronic HIV-1 clade B infection, we identified 284 HLA-APs in Gag, Pol, and Nef using phylogenetically corrected methods. The number of HLA-associated substitutions in Pol, notably those restricted by HLA-B*52:01, was weakly inversely correlated with the plasma viral load (pVL), suggesting that the transmission and persistence of B*52:01-driven Pol mutations could modulate the pVL. Differential selection of HLA-APs between HLA subtype members, including those differing only with respect to substitutions outside the peptide-binding groove, was observed, meriting further investigation as to their mechanisms of selection. Notably, two-thirds of HLA-APs identified in Japan had not been reported in previous studies of predominantly Caucasian cohorts and were attributable to HLA alleles unique to, or enriched in, Japan. We also identified 71 cases where the same HLA allele drove significantly different escape pathways in Japan versus predominantly Caucasian cohorts. Our results underscore the distinct global evolution of HIV-1 clade B as a result of host population-specific cellular immune pressures. Cytotoxic T lymphocyte (CTL) escape mutations in HIV-1 are broadly predictable based on the HLA class I alleles expressed by the host. Because HLA allele distributions differ among

  19. Estimating population sizes for elusive animals: the forest elephants of Kakum National Park, Ghana.

    Science.gov (United States)

    Eggert, L S; Eggert, J A; Woodruff, D S

    2003-06-01

    African forest elephants are difficult to observe in the dense vegetation, and previous studies have relied upon indirect methods to estimate population sizes. Using multilocus genotyping of noninvasively collected samples, we performed a genetic survey of the forest elephant population at Kakum National Park, Ghana. We estimated population size, sex ratio and genetic variability from our data, then combined this information with field observations to divide the population into age groups. Our population size estimate was very close to that obtained using dung counts, the most commonly used indirect method of estimating the population sizes of forest elephant populations. As their habitat is fragmented by expanding human populations, management will be increasingly important to the persistence of forest elephant populations. The data that can be obtained from noninvasively collected samples will help managers plan for the conservation of this keystone species.

  20. Both population size and patch quality affect local extinctions and colonizations.

    Science.gov (United States)

    Franzén, Markus; Nilsson, Sven G

    2010-01-07

    Currently, the habitat of many species is fragmented, resulting in small local populations with individuals occasionally dispersing between the remaining habitat patches. In a solitary bee metapopulation, extinction probability was related to both local bee population sizes and pollen resources measured as host plant population size. Patch size, on the other hand, had no additional predictive power. The turnover rate of local bee populations in 63 habitat patches over 4 years was high, with 72 extinction events and 31 colonization events, but the pollen plant population was stable with no extinctions or colonizations. Both pollen resources and bee populations had strong and independent effects on extinction probability, but connectivity was not of importance. Colonizations occurred more frequently within larger host plant populations. For metapopulation survival of the bee, large pollen plant populations are essential, independent of current bee population size.

  1. Cardiovascular risk in an HIV-infected population in India.

    Science.gov (United States)

    Marbaniang, Ivan P; Kadam, Dileep; Suman, Rohan; Gupte, Nikhil; Salvi, Sonali; Patil, Sandesh; Shere, Dhananjay; Deshpande, Prasad; Kulkarni, Vandana; Deluca, Andrea; Gupta, Amita; Mave, Vidya

    2017-01-01

    To characterise prevalence of traditional cardiovascular disease (CVD) risk factors, assess CVD risk and examine the effect of simulated interventions on CVD risk among HIV-infected Asian Indians. Cross-sectional data between September 2015 and July 2016 wer used to describe the prevalence of CVD risk factors. Five risk scores (Framingham, Data Collection on Adverse Effects of Anti-HIV Drugs Study (D:A:D), Atherosclerotic Cardiovascular, QRISK2 and Ramathibodi-Electricity Generating Authority of Thailand were used to estimate CVD risk. The effect of seven sensitivity analyses: smoking prevention; diabetes prevention; optimal blood pressure and dyslipidaemia control (total cholesterol, high-density lipoprotein (HDL)); CD4 augmentation and a combination of the scenarios on the median cumulative D:A:D CVD scores were assessed. Of 402 enrolled, 56% were women, median age was 40 years (IQR: 35-45 years) and median time-updated CD4 counts were 378 cells/μL (IQR: 246-622). Fifty-five and 28% had ever been screened for hypertension and diabetes, respectively prior to enrolment. The prevalence of diabetes, hypertension, hypercholesterolaemia, low HDL, previous and current smokers were 9%, 22%, 20%, 39%, 14% and 4%, respectively. Thirty-six per cent had intermediate-to-high 5-year CVD risk by D:A:D estimates. Thirty-two per cent were eligible for statin therapy by American College of Cardiology/American Heart Association guidelines; 2% were currently on statins. In sensitivity analyses, diabetes prevention was associated with the highest reduction of CVD risk. CVD at younger ages among Asian Indian people living with HIV appear to be an imminent risk for morbidity. Stepping up of preventive services including screening services and prescription of statins are important strategies that must be considered.

  2. Population size, survival, growth, and movements of Rana sierrae

    Science.gov (United States)

    Fellers, Gary M.; Kleeman, Patrick M.; Miller, David A. W.; Halstead, Brian J.; Link, William

    2013-01-01

    Based on 2431 captures of 757 individual frogs over a 9-yr period, we found that the population of R. sierrae in one meadow–stream complex in Yosemite National Park ranged from an estimated 45 to 115 adult frogs. Rana sierrae at our relatively low elevation site (2200 m) grew at a fast rate (K = 0.73–0.78), had high overwintering survival rates (44.6–95%), lived a long time (up to 16 yr), and tended to be fairly sedentary during the summer (100% minimum convex polygon annual home ranges of 139 m2) but had low year-to-year site fidelity. Even though the amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) has been present in the population for at least 13 yr, there was no clear downward trend as might be expected from reports of R. sierrae population declines associated with Bd or from reports of widespread population decline of R. sierrae throughout its range.

  3. Sample Size Calculations for Population Size Estimation Studies Using Multiplier Methods With Respondent-Driven Sampling Surveys.

    Science.gov (United States)

    Fearon, Elizabeth; Chabata, Sungai T; Thompson, Jennifer A; Cowan, Frances M; Hargreaves, James R

    2017-09-14

    While guidance exists for obtaining population size estimates using multiplier methods with respondent-driven sampling surveys, we lack specific guidance for making sample size decisions. To guide the design of multiplier method population size estimation studies using respondent-driven sampling surveys to reduce the random error around the estimate obtained. The population size estimate is obtained by dividing the number of individuals receiving a service or the number of unique objects distributed (M) by the proportion of individuals in a representative survey who report receipt of the service or object (P). We have developed an approach to sample size calculation, interpreting methods to estimate the variance around estimates obtained using multiplier methods in conjunction with research into design effects and respondent-driven sampling. We describe an application to estimate the number of female sex workers in Harare, Zimbabwe. There is high variance in estimates. Random error around the size estimate reflects uncertainty from M and P, particularly when the estimate of P in the respondent-driven sampling survey is low. As expected, sample size requirements are higher when the design effect of the survey is assumed to be greater. We suggest a method for investigating the effects of sample size on the precision of a population size estimate obtained using multipler methods and respondent-driven sampling. Uncertainty in the size estimate is high, particularly when P is small, so balancing against other potential sources of bias, we advise researchers to consider longer service attendance reference periods and to distribute more unique objects, which is likely to result in a higher estimate of P in the respondent-driven sampling survey. ©Elizabeth Fearon, Sungai T Chabata, Jennifer A Thompson, Frances M Cowan, James R Hargreaves. Originally published in JMIR Public Health and Surveillance (http://publichealth.jmir.org), 14.09.2017.

  4. Clinical and immunological status of a newly diagnosed HIV positive population, in Marrakech, Morocco.

    Science.gov (United States)

    Admou, B; Elharti, E; Oumzil, H; Addebbous, A; Amine, M; Zahlane, K; Soraa, N; Zougaghi, L; Haouach, K; Tassi, N; Aajly, L; Chabaa, L; El Aouad, R

    2010-12-01

    To evaluate the clinical and the immune status of newly HIV diagnosed patients, in Marrakech city and its neighboring area, in Morocco. We performed a retrospective study on 235 patients who have been previously confirmed for HIV infection, and underwent a CD4 T cells using flow cytometry (FacsCount, Becton Dickinson®). The mean age of patients was 34,3 ± 8,4 years (range: 14-55), with a male predominance (sex-ratio M/F=1.4). On basis of clinical data of the patients, 62% (n=146) of them were categorized as "category C", 18.4% (n=43) as "category B", and 19.6% (n=46) as "category A" according to CDC (Center for Disease Control) HIV classification. Among all of them, 60.4% (n=142) had less than 200 CD4T cells, 26% (n=61) had between 200 and 499 CD4T cells, and only 13.6% (n=32) showed a number of CD4T cells less or equal to 500/mm(3). The results of this study reflect a significant delay in the diagnosis of HIV infected patients. Therefore, this delay may compromise timely management of HIV infected individuals and enhances propagation of the epidemic in our country. These data confirm the need for intensifying prevention efforts among high-risk population. Moreover, continuing education in HIV/AIDS among healthcare providers should be reinforced.

  5. Remodelling core group theory: the role of sustaining populations in HIV transmission.

    Science.gov (United States)

    Watts, Charlotte; Zimmerman, Cathy; Foss, Anna M; Hossain, Mazeda; Cox, Andrew; Vickerman, Peter

    2010-12-01

    Core group theory describes the central role of groups with high rates of sexual partner change in HIV transmission. Research illustrates the heterogeneous and dynamic nature of commercial sex, and that some men involved in the organisation or policing of sex work regularly have sex with sex workers. These findings are used to explore gaps in core group theory. Evidence from developing countries on the duration that women sell and men buy sex was reviewed. Simple compartmental dynamic models were used to derive analytical expressions for the relative HIV equilibrium levels among sex workers and partners, incorporating partner change rates and duration in commercial sex settings. Simulations explored the degree to which HIV infection can be attributable to men with low partner change rates who remain in sex work settings for long periods, and their influence on the impact of HIV intervention. Partner change rates and duration of time in a setting determine equilibrium HIV levels. Modelling projections suggest that men with low mobility can substantially contribute to HIV prevalence among sex workers, especially in settings with prevalences group theory. Men who control the sex industry and regular clients may form an important 'sustaining population' that increases infection and undermines the impact of intervention. Intervention activities should include these groups, and examine the social organisation of sex work that underpins many of these relationships.

  6. Personal Risk Perception, HIV Knowledge and Risk Avoidance Behavior, and Their Relationships to Actual HIV Serostatus in an Urban African Obstetric Population

    Science.gov (United States)

    Stringer, Elizabeth M.; Sinkala, Moses; Kumwenda, Rosemary; Chapman, Victoria; Mwale, Alexandrina; Vermund, Sten H.; Goldenberg, Robert L.; Stringer, Jeffrey S.A.

    2009-01-01

    One quarter of pregnant women in Zambia are infected with HIV. Understanding how knowledge of HIV relates to personal risk perception and avoidance of risky behaviors is critical to devising effective HIV prevention strategies. In conjunction with a large clinical trial in Lusaka, Zambia, we surveyed postpartum women who had been tested for HIV but did not know their status before undergoing the questionnaire. Of 858 women for whom complete data were available, 248 (29%) were HIV infected. Women 22 years of age or older (adjusted odds ratio [AOR], 1.7; 95% confidence interval [CI], 1.1–2.5), women reporting ≥2 sexual partners in their lifetime (AOR, 1.8; 95% CI, 1.3–2.5), and women reporting a history of a sexually transmitted infection (AOR, 2.7; 95% CI, 1.7–4.3) were more likely to be HIV infected. Having had ≥2 lifetime sexual partners was a marker for perception of high personnel risk for HIV infection (AOR, 1.5; 95% CI, 1.1–2.1). However, there was no relationship between perceived risk of HIV infection and actual HIV status. In fact, 127 (52%) of 245 women who stated that they were at no or low risk for HIV infection were HIV infected. Living in an area of high HIV seroprevalence like Zambia seems to be the greatest risk factor for infection in unselected pregnant women. Before significant inroads can be made in decreasing the incidence of HIV infection among pregnant women, population-based strategies that involve men must be implemented. PMID:14707794

  7. Epidemiological Profile and Risk Factors for Acquiring HBV and/or HCV in HIV-Infected Population Groups in Nepal.

    Science.gov (United States)

    Bhattarai, Manjula; Baniya, Jagat Bahadur; Aryal, Nirmal; Shrestha, Bimal; Rauniyar, Ramanuj; Adhikari, Anurag; Koirala, Pratik; Oli, Pardip Kumar; Pandit, Ram Deo; Stein, David A; Gupta, Birendra Prasad

    2018-01-01

    HBV and HCV infections are widespread among the HIV-infected individuals in Nepal. The goals of this study were to investigate the epidemiological profile and risk factors for acquiring HBV and/or HCV coinfection in disadvantaged HIV-positive population groups in Nepal. We conducted a retrospective study on blood samples from HIV-positive patients from the National Public Health Laboratory at Kathmandu to assay for HBsAg, HBeAg, and anti-HCV antibodies, HIV viral load, and CD4+ T cell count. Among 579 subjects, the prevalence of HIV-HBV, HIV-HCV, and HIV-HBV-HCV coinfections was 3.62%, 2.93%, and 0.34%, respectively. Multivariate regression analysis indicated that spouses of HIV-positive migrant labourers were at significant risk for coinfection with HBV infection, and an age of >40 years in HIV-infected individuals was identified as a significant risk factor for HCV coinfection. Overall our study indicates that disadvantaged population groups such as intravenous drug users, migrant workers and their spouses, female sex workers, and men who have sex with HIV-infected men are at a high and persistent risk of acquiring viral hepatitis. We conclude that Nepalese HIV patients should receive HBV and HCV diagnostic screening on a regular basis.

  8. Prevalence and risk of hepatitis e virus infection in the HIV population of Nepal

    NARCIS (Netherlands)

    Shrestha, A. (Ananta); Adhikari, A. (Anurag); Bhattarai, M. (Manjula); Rauniyar, R. (Ramanuj); J.D. Debes; P.A. Boonstra (André); Lama, T.K. (Thupten K.); Al Mahtab, M. (Mamun); Butt, A.S. (Amna Subhan); Akbar, S.M.F. (Sheikh Mohammad Fazle); Aryal, N. (Nirmal); Karn, S. (Sapana); Manandhar, K.D. (Krishna Das); Gupta, B.P. (Birendra Prasad)

    2017-01-01

    textabstractBackground: Infection with the hepatitis E virus (HEV) can cause acute hepatitis in endemic areas in immune-competent hosts, as well as chronic infection in immune-compromised subjects in non-endemic areas. Most studies assessing HEV infection in HIV-infected populations have been

  9. Mortality by causes in HIV-infected adults: comparison with the general population

    Directory of Open Access Journals (Sweden)

    Floristan Yugo

    2011-05-01

    Full Text Available Abstract Background We compared mortality by cause of death in HIV-infected adults in the era of combined antiretroviral therapy with mortality in the general population in the same age and sex groups. Methods Mortality by cause of death was analyzed for the period 1999-2006 in the cohort of persons aged 20-59 years diagnosed with HIV infection and residing in Navarre (Spain. This was compared with mortality from the same causes in the general population of the same age and sex using standardized mortality ratios (SMR. Results There were 210 deaths among 1145 persons diagnosed with HIV (29.5 per 1000 person-years. About 50% of these deaths were from AIDS. Persons diagnosed with HIV infection had exceeded all-cause mortality (SMR 14.0, 95% CI 12.2 to 16.1 and non-AIDS mortality (SMR 6.9, 5.7 to 8.5. The analysis showed excess mortality from hepatic disease (SMR 69.0, 48.1 to 78.6, drug overdose or addiction (SMR 46.0, 29.2 to 69.0, suicide (SMR 9.6, 3.8 to 19.7, cancer (SMR 3.2, 1.8 to 5.1 and cardiovascular disease (SMR 3.1, 1.3 to 6.1. Mortality in HIV-infected intravenous drug users did not change significantly between the periods 1999-2002 and 2003-2006, but it declined by 56% in non-injecting drug users (P = 0.007. Conclusions Persons with HIV infection continue to have considerable excess mortality despite the availability of effective antiretroviral treatments. However, excess mortality in the HIV patients has declined since these treatments were introduced, especially in persons without a history of intravenous drug use.

  10. Genetic variability of sexual size dimorphism in a natural population ...

    Indian Academy of Sciences (India)

    Unknown

    Most animal species exhibit sexual size dimorphism (SSD). SSD is a trait difficult to ...... 26, 15–28. Charnov E. L. 1982 The theory of sex allocation. Princeton .... success in Drosophila melanogaster: the roles of male and female behavior. Anim ...

  11. Cryo-electron microscopy and single molecule fluorescent microscopy detect CD4 receptor induced HIV size expansion prior to cell entry

    International Nuclear Information System (INIS)

    Pham, Son; Tabarin, Thibault; Garvey, Megan; Pade, Corinna; Rossy, Jérémie; Monaghan, Paul; Hyatt, Alex; Böcking, Till; Leis, Andrew; Gaus, Katharina; Mak, Johnson

    2015-01-01

    Viruses are often thought to have static structure, and they only remodel after the viruses have entered target cells. Here, we detected a size expansion of virus particles prior to viral entry using cryo-electron microscopy (cryo-EM) and single molecule fluorescence imaging. HIV expanded both under cell-free conditions with soluble receptor CD4 (sCD4) targeting the CD4 binding site on the HIV-1 envelope protein (Env) and when HIV binds to receptor on cellular membrane. We have shown that the HIV Env is needed to facilitate receptor induced virus size expansions, showing that the ‘lynchpin’ for size expansion is highly specific. We demonstrate that the size expansion required maturation of HIV and an internal capsid core with wild type stability, suggesting that different HIV compartments are linked and are involved in remodelling. Our work reveals a previously unknown event in HIV entry, and we propose that this pre-entry priming process enables HIV particles to facilitate the subsequent steps in infection. - Highlights: • Cell free viruses are able to receive external trigger that leads to apparent size expansion. • Virus envelope and CD4 receptor engagement is the lynchpin of virus size expansion. • Internal capsid organisation can influence receptor mediated virus size expansion. • Pre-existing virus-associated lipid membrane in cell free virus can accommodate the receptor mediated virus size expansion.

  12. Cryo-electron microscopy and single molecule fluorescent microscopy detect CD4 receptor induced HIV size expansion prior to cell entry

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Son [Deakin University, Victoria 3216 (Australia); CSIRO Australian Animal Health Laboratory, Victoria 3220 (Australia); Tabarin, Thibault [ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, New South Wales 3220 (Australia); Garvey, Megan; Pade, Corinna [Deakin University, Victoria 3216 (Australia); CSIRO Australian Animal Health Laboratory, Victoria 3220 (Australia); Rossy, Jérémie [ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, New South Wales 3220 (Australia); Monaghan, Paul; Hyatt, Alex [CSIRO Australian Animal Health Laboratory, Victoria 3220 (Australia); Böcking, Till [ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, New South Wales 3220 (Australia); Leis, Andrew [CSIRO Australian Animal Health Laboratory, Victoria 3220 (Australia); Gaus, Katharina, E-mail: k.gaus@unsw.edu.au [ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, New South Wales 3220 (Australia); Mak, Johnson, E-mail: j.mak@deakin.edu.au [Deakin University, Victoria 3216 (Australia); CSIRO Australian Animal Health Laboratory, Victoria 3220 (Australia)

    2015-12-15

    Viruses are often thought to have static structure, and they only remodel after the viruses have entered target cells. Here, we detected a size expansion of virus particles prior to viral entry using cryo-electron microscopy (cryo-EM) and single molecule fluorescence imaging. HIV expanded both under cell-free conditions with soluble receptor CD4 (sCD4) targeting the CD4 binding site on the HIV-1 envelope protein (Env) and when HIV binds to receptor on cellular membrane. We have shown that the HIV Env is needed to facilitate receptor induced virus size expansions, showing that the ‘lynchpin’ for size expansion is highly specific. We demonstrate that the size expansion required maturation of HIV and an internal capsid core with wild type stability, suggesting that different HIV compartments are linked and are involved in remodelling. Our work reveals a previously unknown event in HIV entry, and we propose that this pre-entry priming process enables HIV particles to facilitate the subsequent steps in infection. - Highlights: • Cell free viruses are able to receive external trigger that leads to apparent size expansion. • Virus envelope and CD4 receptor engagement is the lynchpin of virus size expansion. • Internal capsid organisation can influence receptor mediated virus size expansion. • Pre-existing virus-associated lipid membrane in cell free virus can accommodate the receptor mediated virus size expansion.

  13. Respondent-driven sampling (rds as a new method to access vulnerable populations to hiv: its application in men who have sex with men

    Directory of Open Access Journals (Sweden)

    John H. Estrada M

    2010-11-01

    Full Text Available Approximately 30 million people are living with hiv all around the world in 2010. The most vulnerable hiv/aids groups are sex workers, intravenous drug users, transgender people and population of men who have sex with men (msm. Up to now, the surveillance and behavioral studies on sexual transmitted diseases (sti and hiv have been conducted using intentional sampling methods like the snowball methodology, but this kind of sampling does not achieve representation and does not represent a conclusive method for the study of hidden populations in order to extend and apply its results to the general population. Furthermore, it is necessary to add to this limitation the lack of knowledge about the size of these groups that must face situations of stigma and discrimination. A decade ago a new method was designed to sample hidden and hard to reach populations based on Markov theories and on chain recruitment. This new method is known as respondent-driven sampling (rds and it has been used in several behavioral and hiv prevalence studies. This review article presents the background, the theoretical support and a description of the method. It also analyzes some studies carried out using this new methodology.

  14. Increase in Unemployment over the 2000's: Comparison between People Living with HIV and the French General Population.

    Science.gov (United States)

    Annequin, Margot; Lert, France; Spire, Bruno; Dray-Spira, Rosemary

    2016-01-01

    Despite improved health, unemployment has increased among people living with HIV (PlwHIV) over the last decade. However, since the economic recession of 2008, unemployment also increased in the French general population. This paper aimed to determine if the increase in the unemployment rate in the HIV population was higher than that in the French general population. We used data from the ANRS-Vespa study, a repeated cross-sectional survey among two national representative samples of PlwHIV followed at hospitals in France in 2003 and 2011. We compared employment and unemployment rates between HIV-infected people (overall and according to period of HIV diagnosis) and the French general population in 2003 and 2011, using multivariate Poisson regressions adjusted for individual sociodemographic characteristics. The employment rate among PlwHIV was consistently lower than that in the general population in 2003 and 2011. In contrast, there was a trend of an increasing unemployment rate difference between PlwHIV and the general population: PlwHIV's unemployment rate was 1.48 (95% confidence interval [CI]: 1.16-1.90) times higher than that of the general population in 2003, versus 1.62 (95% CI: 1.34-1.96) times higher in 2011. This unemployment rate difference was the highest for PlwHIV diagnosed in or after 2008 (adjusted prevalence rate ratio: 2.06; 95% CI: 1.59-2.67). These results suggest that in time of economic recession, an increasing proportion of PlwHIV may be excluded from the labor market although they are willing to re-enter it. This constitutes a major issue relative to social consequences of chronic disease.

  15. A call for differentiated approaches to delivering HIV services to key populations.

    Science.gov (United States)

    Macdonald, Virginia; Verster, Annette; Baggaley, Rachel

    2017-07-21

    Key populations (KPs) are disproportionally affected by HIV and have low rates of access to HIV testing and treatment services compared to the broader population. WHO promotes the use of differentiated approaches for reaching and recruiting KP into the HIV services continuum. These approaches may help increase access to KPs who are often criminalized or stigmatized. By catering to the specific needs of each KP individual, differentiated approaches may increase service acceptability, quality and coverage, reduce costs and support KP members in leading the HIV response among their communities. WHO recommends the implementation of community-based and lay provider administered HIV testing services. Together, these approaches reduce barriers and costs associated with other testing strategies, allow greater ownership in HIV programmes for KP members and reach more people than do facility-based services. Despite this evidence availability and support for them is limited. Peer-driven interventions have been shown to be effective in engaging, recruiting and supporting clients. Some programmes employ HIV-positive or non-PLHIV "peer navigators" and other staff to provide case management, enrolment and/or re-enrolment in care and treatment services. However, a better understanding of the impact, cost effectiveness and potential burden on peer volunteers is required. Task shifting and non-facility-based service locations for antiretroviral therapy (ART) initiation and maintenance and antiretroviral (ARV) distribution are recommended in both the consolidated HIV treatment and KP guidelines of WHO. These approaches are accepted in generalized epidemics and for the general population where successful models exist; however, few organizations provide or initiate ART at KP community-based services. The application of a differentiated service approach for KP could increase the number of people who know their status and receive effective and sustained prevention and treatment for HIV

  16. Food web framework for size-structured populations

    DEFF Research Database (Denmark)

    Hartvig, Martin; Andersen, Ken Haste; Beyer, Jan

    2011-01-01

    . Parameter values are determined from cross-species analysis of fish communities as life-history omnivory is widespread in aquatic systems, but may be reparameterised for other systems. An ensemble of food webs is generated and the resulting communities are analysed at four levels of organisation: community......We synthesise traditional unstructured food webs, allometric body size scaling, trait-based modelling, and physiologically structured modelling to provide a novel and ecologically relevant tool for size-structured food webs. The framework allows food web models to include ontogenetic growth...... level, species level, trait level, and individual level. The model may be solved analytically by assuming that the community spectrum follows a power law. The analytical solution provides a baseline expectation of the results of complex food web simulations, and agrees well with the predictions...

  17. Masculine sex ratios, population age structure and the potential spread of HIV in China

    OpenAIRE

    M. Giovanna Merli; Sara Hertog

    2010-01-01

    There is much speculation regarding the contribution of China's changing demography to the spread of HIV/AIDS. We employ a bio-behavioral macrosimulation model of the heterosexual spread of HIV/AIDS to evaluate the roles that China's unique demographic conditions -- (1) masculine sex ratios at birth and (2) a population age structure that reflects rapid fertility decline since the 1970's -- play in altering the market for sexual partners, thereby potentially fueling an increase...

  18. Risk of myocardial infarction in parents of HIV-infected individuals: a population-based cohort study

    DEFF Research Database (Denmark)

    Rasmussen, Line D; Omland, Lars H; Pedersen, Court

    2010-01-01

    associated with the HIV disease and HAART or whether life-style related or genetic factors also increase the risk in this population. To establish whether the increased risk of myocardial infarction in HIV patients partly reflects an increased risk of MI in their families, we estimated the relative risk...... of MI in parents of HIV-infected individuals METHODS: From the Danish HIV Cohort Study and the Danish Civil Registration System we identified the parents of all HIV-infected patients born in Denmark after 1952 in whom a Danish born mother was identifiable. For each HIV patient, 4 matched population...... controls and their parents were identified. Cumulative incidence functions were constructed to illustrate time to first MI of the parents as registered in the Danish National Hospital Registry. Incidence rate ratios (IRR) were estimated by Cox's regression analyses. Due to the confidential type...

  19. Adherence to the cervical cancer screening program in women living with HIV in Denmark: comparison with the general population.

    Science.gov (United States)

    Thorsteinsson, Kristina; Ladelund, Steen; Jensen-Fangel, Søren; Katzenstein, Terese L; Johansen, Isik Somuncu; Pedersen, Gitte; Junge, Jette; Helleberg, Marie; Storgaard, Merete; Lebech, Anne-Mette

    2014-05-13

    Women living with HIV (WLWH) are at increased risk of invasive cervical cancer (ICC). International HIV guidelines suggest cervical screening twice the first year after HIV diagnosis and thereafter annually. Adherence to the HIV cervical screening program in Denmark is unknown. We studied women from a population-based, nationwide HIV cohort in Denmark and a cohort of age-matched females from the general population. Screening behaviour was assessed from 1999-2010. Adjusted odds ratios (OR's) for screening attendance in the two cohorts and potential predictors of attendance to guidelines were estimated. Pathology specimens were identified from The Danish Pathology Data Bank. We followed 1143 WLWH and 17,145 controls with no prior history of ICC for 9,509 and 157,362 person-years. The first year after HIV diagnosis 2.6% of WLWH obtained the recommended two cervical cytologies. During the different calendar intervals throughout the study period between 29-46% of WLWH followed the HIV cervical screening guidelines. Adjusted OR's of attendance to the general population screening program for WLWH aged 30, 40 and 50 years, compared to controls, were 0.69 (95% CI: 0.56-0.87), 0.67 (0.55-0.80) and 0.84 (0.61-1.15). Predictors of attendance to the HIV cervical screening program were a CD4 count > 350 cells/μL and HIV RNA < 500 copies/mL. Calendar period after 2002 and HIV RNA < 500 copies/mL predicted attendance to the general population cervical screening program. The majority of WLWH do not follow the HIV guidelines for cervical screening. We support the idea of cytology as part of an annual review and integration of HIV care and cervical screening in a single clinic setting.

  20. THE POPULATION IMPACT OF ELIMINATING HOMELESSNESS ON HIV VIRAL SUPPRESSION AMONG PEOPLE WHO USE DRUGS

    Science.gov (United States)

    Marshall, Brandon D.L.; Elston, Beth; Dobrer, Sabina; Parashar, Surita; Hogg, Robert S.; Montaner, Julio S.G.; Kerr, Thomas; Wood, Evan; Milloy, M-J

    2015-01-01

    Objective We sought to estimate the change in viral suppression prevalence if homelessness were eliminated from a population of HIV-infected people who use drugs (PWUD). Design Community-recruited prospective cohort of HIV-infected PWUD in Vancouver, Canada. Behavioral information was collected at baseline and linked to a province-wide HIV/AIDS treatment database. The primary outcome was viral suppression (<50 copies/mL) measured during subsequent routine clinical care. Methods We employed an imputation-based marginal modelling approach. First, we used modified Poisson regression to obtain effect estimates (adjusting for sociodemographics, substance use, addiction treatment, and other confounders). Then, we imputed an outcome probability for each individual while manipulating the exposure (homelessness). Population viral suppression prevalence under realized and “housed” scenarios were obtained by averaging these probabilities across the population. Bootstrapping was conducted to calculate 95% confidence limits. Results Of 706 individuals interviewed between January 2005 and December 2015, the majority was male (66.0%), of Caucasian race/ethnicity (55.1%), and had a history of injection (93.6%). At first study visit, 223 (31.6%) reported recent homelessness, and 37.8% were subsequently identified as virally suppressed. Adjusted marginal models estimated a 15.1% relative increase (95%CI: 9.0%, 21.7%) in viral suppression in the entire population—to 43.5% (95%CI: 39.4%, 48.2%)—if all homeless individuals were housed. Among those homeless, eliminating this exposure would increase viral suppression from 22.0% to 40.1% (95%CI: 35.1%, 46.1%), an 82.3% relative increase. Conclusions Interventions to house homeless, HIV-positive individuals who use drugs could significantly increase population viral suppression. Such interventions should be implemented as a part of renewed HIV/AIDS prevention and treatment efforts. PMID:26636924

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

    Science.gov (United States)

    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

  2. Increase in Unemployment over the 2000’s: Comparison between People Living with HIV and the French General Population

    Science.gov (United States)

    Annequin, Margot; Lert, France; Spire, Bruno; Dray-Spira, Rosemary

    2016-01-01

    Background Despite improved health, unemployment has increased among people living with HIV (PlwHIV) over the last decade. However, since the economic recession of 2008, unemployment also increased in the French general population. This paper aimed to determine if the increase in the unemployment rate in the HIV population was higher than that in the French general population. Methods We used data from the ANRS-Vespa study, a repeated cross-sectional survey among two national representative samples of PlwHIV followed at hospitals in France in 2003 and 2011. We compared employment and unemployment rates between HIV-infected people (overall and according to period of HIV diagnosis) and the French general population in 2003 and 2011, using multivariate Poisson regressions adjusted for individual sociodemographic characteristics. Results The employment rate among PlwHIV was consistently lower than that in the general population in 2003 and 2011. In contrast, there was a trend of an increasing unemployment rate difference between PlwHIV and the general population: PlwHIV’s unemployment rate was 1.48 (95% confidence interval [CI]: 1.16–1.90) times higher than that of the general population in 2003, versus 1.62 (95% CI: 1.34–1.96) times higher in 2011. This unemployment rate difference was the highest for PlwHIV diagnosed in or after 2008 (adjusted prevalence rate ratio: 2.06; 95% CI: 1.59–2.67). Conclusions These results suggest that in time of economic recession, an increasing proportion of PlwHIV may be excluded from the labor market although they are willing to re-enter it. This constitutes a major issue relative to social consequences of chronic disease. PMID:27814374

  3. Infection-related and -unrelated malignancies, HIV and the aging population.

    Science.gov (United States)

    Shepherd, L; Borges, Áh; Ledergerber, B; Domingo, P; Castagna, A; Rockstroh, J; Knysz, B; Tomazic, J; Karpov, I; Kirk, O; Lundgren, J; Mocroft, A

    2016-09-01

    HIV-positive people have increased risk of infection-related malignancies (IRMs) and infection-unrelated malignancies (IURMs). The aim of the study was to determine the impact of aging on future IRM and IURM incidence. People enrolled in EuroSIDA and followed from the latest of the first visit or 1 January 2001 until the last visit or death were included in the study. Poisson regression was used to investigate the impact of aging on the incidence of IRMs and IURMs, adjusting for demographic, clinical and laboratory confounders. Linear exponential smoothing models forecasted future incidence. A total of 15 648 people contributed 95 033 person-years of follow-up, of whom 610 developed 643 malignancies [IRMs: 388 (60%); IURMs: 255 (40%)]. After adjustment, a higher IRM incidence was associated with a lower CD4 count [adjusted incidence rate ratio (aIRR) CD4 count IRMs. The incidences of both IURMs and IRMs increased with older age. It was projected that the incidence of IRMs would decrease by 29% over a 5-year period from 3.1 (95% CI 1.5-5.9) per 1000 person-years in 2011, whereas the IURM incidence would increase by 44% from 4.1 (95% CI 2.2-7.2) per 1000 person-years over the same period. Demographic and HIV-related risk factors for IURMs (aging and smoking) and IRMs (immunodeficiency and ongoing viral replication) differ markedly and the contribution from IURMs relative to IRMs will continue to increase as a result of aging of the HIV-infected population, high smoking and lung cancer prevalence and a low prevalence of untreated HIV infection. These findings suggest the need for targeted preventive measures and evaluation of the cost-benefit of screening for IURMs in HIV-infected populations. © 2016 British HIV Association.

  4. An epidemiological modelling study to estimate the composition of HIV-positive populations including migrants from endemic settings

    DEFF Research Database (Denmark)

    Nakagawa, F; Delpech, V; Albert, J

    2017-01-01

    were undiagnosed respectively. CONCLUSION: We have shown a working example to characterize the HIV population in a European context which incorporates migrants from countries with generalized epidemics. Despite all aspects of HIV care being free and widely available to anyone in need in the UK......OBJECTIVE: Migrants account for a significant number of people living with HIV in Europe, and it is important to fully consider this population in national estimates. Using a novel approach with the UK as an example, we present key public health measures of the HIV epidemic, taking into account...... of these people, 24 600 (15 000-36 200) were estimated to be undiagnosed; this number has remained stable over the last decade. An estimated 32% of the total undiagnosed population had CD4 cell count less than 350 cells/μl in 2013. Twenty-five and 23% of black African men and women heterosexuals living with HIV...

  5. Thymic size in uninfected infants born to HIV-positive mothers and fed with pasteurized human milk.

    Science.gov (United States)

    Jeppesen, D; Hasselbalch, H; Ersbøll, A K; Heilmann, C; Valerius, N H

    2003-06-01

    To examine the size of the thymus in uninfected infants born to HIV-positive mothers and to study the effects of feeding by human donor milk on the size of the thymus in these infants. The absolute and relative thymic size was assessed by sonography as thymic index (Ti), and the Ti/weight-ratio (Ti/w) at birth and at 4 mo of age in 12 healthy uninfected infants born to HlV-infected mothers. All infants were exclusively fed pasteurized donor milk. The results were compared with those obtained from a previous cohort of exclusively breastfed, partially breastfed and exclusively formula-fed infants. At birth the Ti was reduced in infants born to HIV-infected mothers in comparison with that in control infants but this difference disappeared when their birthweights were taken into consideration (Ti/w-ratio). At 4 mo of age the geometric mean Ti of infants fed donor milk was 23.8 and the mean Ti/w-ratio was 4.2. Compared with those of exclusively breastfed infants, the Ti and Ti/w-ratio of infants fed donor milk were significantly reduced (p milk-fed infants compared with that in the formula-fed infants (p = 0.02). At birth the size of the thymus was smaller in uninfected infants of HIV-positive mothers compared with infants of HIV-negative mothers but when birthweight was taken into account this difference disappeared. Feeding by human donor milk seemed to result in an increased size of the thymus at 4 mo of age compared with thymic size in infants that were exclusively formula fed.

  6. The potential global market size and public health value of an HIV-1 vaccine in a complex global market.

    Science.gov (United States)

    Marzetta, Carol A; Lee, Stephen S; Wrobel, Sandra J; Singh, Kanwarjit J; Russell, Nina; Esparza, José

    2010-07-05

    An effective HIV vaccine will be essential for the control of the HIV pandemic. This study evaluated the potential global market size and value of a hypothetical HIV vaccine and considered clade diversity, disease burden, partial prevention of acquisition, impact of a reduction in viral load resulting in a decrease in transmission and delay to treatment, health care system differences regarding access, and HIV screening and vaccination, across all public and private markets. Vaccine product profiles varied from a vaccine that would have no effect on preventing infection to a vaccine that would effectively prevent infection and reduce viral load. High disease burden countries (HDBC; HIV prevalence > or = 1%) were assumed to routinely vaccinate pre-sexually active adolescents (10 years old), whereas low disease burden countries (LDBC; HIV prevalence rate market value of $210 million to $2.7 billion, depending on the vaccine product profile. If one-time catch-up campaigns were included (11-14 years old for HDBC and higher risk groups for LDBC), the additional cumulative approximately 70-237 million doses were needed over a 10-year period with a potential market value of approximately $695 million to $13.4 billion, depending on the vaccine product profile. Market size and value varied across market segments with the majority of the value in high income countries and the majority of the demand in low income countries. However, the value of the potential market in low income countries is still significant with up to $550 million annually for routine vaccination only and up to $1.7 billion for a one-time only catch-up campaign in 11-14 years old. In the most detail to date, this study evaluated market size and value of a potential multi-clade HIV vaccine, accounting for differences in disease burden, product profile and health care complexities. These findings provide donors and suppliers highly credible new data to consider in their continued efforts to develop an HIV-1

  7. Noninvasive genetics provides insights into the population size and genetic diversity of an Amur tiger population in China.

    Science.gov (United States)

    Wang, Dan; Hu, Yibo; Ma, Tianxiao; Nie, Yonggang; Xie, Yan; Wei, Fuwen

    2016-01-01

    Understanding population size and genetic diversity is critical for effective conservation of endangered species. The Amur tiger (Panthera tigris altaica) is the largest felid and a flagship species for wildlife conservation. Due to habitat loss and human activities, available habitat and population size are continuously shrinking. However, little is known about the true population size and genetic diversity of wild tiger populations in China. In this study, we collected 55 fecal samples and 1 hair sample to investigate the population size and genetic diversity of wild Amur tigers in Hunchun National Nature Reserve, Jilin Province, China. From the samples, we determined that 23 fecal samples and 1 hair sample were from 7 Amur tigers: 2 males, 4 females and 1 individual of unknown sex. Interestingly, 2 fecal samples that were presumed to be from tigers were from Amur leopards, highlighting the significant advantages of noninvasive genetics over traditional methods in studying rare and elusive animals. Analyses from this sample suggested that the genetic diversity of wild Amur tigers is much lower than that of Bengal tigers, consistent with previous findings. Furthermore, the genetic diversity of this Hunchun population in China was lower than that of the adjoining subpopulation in southwest Primorye Russia, likely due to sampling bias. Considering the small population size and relatively low genetic diversity, it is urgent to protect this endangered local subpopulation in China. © 2015 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

  8. Risk of myocardial infarction in parents of HIV-infected Individuals: a population-based Cohort Study

    DEFF Research Database (Denmark)

    Rasmussen, Line D; Omland, Lars H; Pedersen, Court

    2010-01-01

    with the HIV disease and HAART or whether life-style related or genetic factors also increase the risk in this population. To establish whether the increased risk of myocardial infarction in HIV patients partly reflects an increased risk of MI in their families, we estimated the relative risk of MI in parents...

  9. Detecting population recovery using gametic disequilibrium-based effective population size estimates

    Science.gov (United States)

    David A. Tallmon; Robin S. Waples; Dave Gregovich; Michael K. Schwartz

    2012-01-01

    Recovering populations often must meet specific growth rate or abundance targets before their legal status can be changed from endangered or threatened. While the efficacy, power, and performance of population metrics to infer trends in declining populations has received considerable attention, how these same metrics perform when populations are increasing is less...

  10. [Population mobility and HIV/AIDS in Central America and Mexico].

    Science.gov (United States)

    Leyva-Flores, René; Aracena-Genao, Belkis; Serván-Mori, Edson

    2014-09-01

    Estimate the magnitude of the association between population mobility, measured by net migration rate (NMR), and HIV prevalence in Central America and Mexico. Using time series models, based on public information from UNAIDS, UNDP, ECLAC, and the World Bank for the period 1990-2009, this association was studied in individuals aged 15-49 years, and adjusted for socioeconomic factors (education, unemployment, life expectancy, and income). NMR was negative in all countries except Costa Rica and Panama. Unadjusted results of the model show a positive association and that NMR can explain 6% of recorded HIV prevalence. When socioeconomic cofactors are included by country (education, health, and income), the magnitude increases to 9% (PCentral America and Mexico, although large gaps persist among countries. The modest association observed between population mobility and HIV prevalence is conditioned by the socioeconomic status of the countries studied. Information availability limited the study's ability to establish the existence of this association with greater certainty. Accordingly, based on available information, it is not possible to affirm that migration plays a key role in the spread of HIV.

  11. Andean Condor (Vultur gryphus) in Ecuador: Geographic Distribution, Population Size and Extinction Risk.

    Science.gov (United States)

    Naveda-Rodríguez, Adrián; Vargas, Félix Hernán; Kohn, Sebastián; Zapata-Ríos, Galo

    2016-01-01

    The Andean Condor (Vultur gryphus) in Ecuador is classified as Critically Endangered. Before 2015, standardized and systematic estimates of geographic distribution, population size and structure were not available for this species, hampering the assessment of its current status and hindering the design and implementation of effective conservation actions. In this study, we performed the first quantitative assessment of geographic distribution, population size and population viability of Andean Condor in Ecuador. We used a methodological approach that included an ecological niche model to study geographic distribution, a simultaneous survey of 70 roosting sites to estimate population size and a population viability analysis (PVA) for the next 100 years. Geographic distribution in the form of extent of occurrence was 49 725 km2. During a two-day census, 93 Andean Condors were recorded and a population of 94 to 102 individuals was estimated. In this population, adult-to-immature ratio was 1:0.5. In the modeled PVA scenarios, the probability of extinction, mean time to extinction and minimum population size varied from zero to 100%, 63 years and 193 individuals, respectively. Habitat loss is the greatest threat to the conservation of Andean Condor populations in Ecuador. Population size reduction in scenarios that included habitat loss began within the first 15 years of this threat. Population reinforcement had no effects on the recovery of Andean Condor populations given the current status of the species in Ecuador. The population size estimate presented in this study is the lower than those reported previously in other countries where the species occur. The inferences derived from the population viability analysis have implications for Condor management in Ecuador. This study highlights the need to redirect efforts from captive breeding and population reinforcement to habitat conservation.

  12. Are slum dwellers at heightened risk of HIV infection than other urban residents? Evidence from population-based HIV prevalence surveys in Kenya.

    Science.gov (United States)

    Madise, Nyovani J; Ziraba, Abdhalah K; Inungu, Joseph; Khamadi, Samoel A; Ezeh, Alex; Zulu, Eliya M; Kebaso, John; Okoth, Vincent; Mwau, Matilu

    2012-09-01

    In 2008, the global urban population surpassed the rural population and by 2050 more than 6 billion will be living in urban centres. A growing body of research has reported on poor health outcomes among the urban poor but not much is known about HIV prevalence among this group. A survey of nearly 3000 men and women was conducted in two Nairobi slums in Kenya between 2006 and 2007, where respondents were tested for HIV status. In addition, data from the 2008/2009 Kenya Demographic and Health Survey were used to compare HIV prevalence between slum residents and those living in other urban and rural areas. The results showed strong intra-urban differences. HIV was 12% among slum residents compared with 5% and 6% among non-slum urban and rural residents, respectively. Generally, men had lower HIV prevalence than women although in the slums the gap was narrower. Among women, sexual experience before the age of 15 compared with after 19 years was associated with 62% higher odds of being HIV positive. There was ethnic variation in patterns of HIV infection although the effect depended on the current place of residence. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Factors associated with willingness to accept oral fluid HIV rapid testing among most-at-risk populations in China.

    Directory of Open Access Journals (Sweden)

    Huanmiao Xun

    Full Text Available The availability of oral fluid HIV rapid testing provides an approach that may have the potential to expand HIV testing in China, especially among most-a-risk populations. There are few investigations about the acceptability of oral fluid HIV testing among most-at-risk populations in China.A cross-sectional study with men who have sex with men (MSM, female sex workers (FSW and voluntary counseling and testing (VCT clients was conducted in three cities of Shandong province, China from 2011 to 2012. Data were collected by face-to-face questionnaire.About 71% of participants were willing to accept the oral fluid HIV rapid testing, and home HIV testing was independently associated with acceptability of the new testing method among MSM, FSW and VCT clients (AOR of 4.46, 3.19 and 5.74, respectively. Independent predictors of oral fluid HIV rapid testing acceptability among MSM were having ever taken an oral fluid HIV rapid test (AOR= 15.25, having ever taken an HIV test (AOR= 2.07, and education level (AOR= 1.74. Engagement in HIV-related risk behaviors (AOR= 1.68 was an independent predictor of acceptability for FSW. Having taken an HIV test (AOR= 2.85 was an independent predictor of acceptability for VCT clients. The primary concern about the oral fluid HIV testing was accuracy. The median price they would pay for the testing ranged from 4.8 to 8.1 U.S. dollars.High acceptability of oral fluid HIV rapid testing was shown among most-at-risk populations. Findings provide support for oral rapid HIV testing as another HIV prevention tool, and provide a backdrop for the implementation of HIV home testing in the near future. Appropriate pricing and increased public education through awareness campaigns that address concerns about the accuracy and safety of the oral fluid HIV rapid testing may help increase acceptability and use among most-at-risk populations in China.

  14. B-graph sampling to estimate the size of a hidden population

    NARCIS (Netherlands)

    Spreen, M.; Bogaerts, S.

    2015-01-01

    Link-tracing designs are often used to estimate the size of hidden populations by utilizing the relational links between their members. A major problem in studies of hidden populations is the lack of a convenient sampling frame. The most frequently applied design in studies of hidden populations is

  15. Burden, Determinants, and Pharmacological Management of Hypertension in HIV-Positive Patients and Populations: A Systematic Narrative Review.

    Science.gov (United States)

    Nguyen, Kim Anh; Peer, Nasheeta; Mills, Edward J; Kengne, Andre Pascal

    2015-01-01

    Hypertension among HIV-positive populations has emerged as a new threat to the health and well being of people living with HIV, particularly among those receiving antiretroviral therapy. We reviewed the global evidence on the burden of disease (including prevalence and incidence), determinants of hypertension among HIV-positive populations, and the pharmacological management of hypertension in HIV-positive patients. We systematically searched PubMed-MEDLINE and EMBASE from January 2000 through February 2015 for relevant studies and traced their citations through the ISI Web of Science. We also searched the websites of the World Health Organisation, the International Society of Hypertension, and the International AIDS Society and constructed a narrative data synthesis. Hypertension is common in HIV-positive populations, with prevalence estimates ranging from 4.7 to 54.4% in high-income countries, and from 8.7 to 45.9% in low- and middle-income countries. The role of HIV-specific factors including disease severity, duration of disease, and treatments on the presence of hypertension in HIV-positive patients is reported, but patterns remain unclear. The clinical management of hypertension in HIV-positive patients is similar to those with hypertension in the general population; however, additional considerations should be given to potential drug interactions between antihypertensive agents and antiretroviral drugs to inform the clinician's selection of these therapies. Hypertension is common in HIV-positive populations and remains an important comorbidity affecting mortality outcomes. Further research examining the development of hypertension and its associated care in HIV-positive patients is required to optimize management of the dual conditions.

  16. Sibship reconstruction for inferring mating systems, dispersal and effective population size in headwater brook trout (Salvelinus fontinalis) populations

    Science.gov (United States)

    Kanno, Yoichiro; Vokoun, Jason C.; Letcher, Benjamin H.

    2011-01-01

    Brook trout Salvelinus fontinalis populations have declined in much of the native range in eastern North America and populations are typically relegated to small headwater streams in Connecticut, USA. We used sibship reconstruction to infer mating systems, dispersal and effective population size of resident (non-anadromous) brook trout in two headwater stream channel networks in Connecticut. Brook trout were captured via backpack electrofishing using spatially continuous sampling in the two headwaters (channel network lengths of 4.4 and 7.7 km). Eight microsatellite loci were genotyped in a total of 740 individuals (80–140 mm) subsampled in a stratified random design from all 50 m-reaches in which trout were captured. Sibship reconstruction indicated that males and females were both mostly polygamous although single pair matings were also inferred. Breeder sex ratio was inferred to be nearly 1:1. Few large-sized fullsib families (>3 individuals) were inferred and the majority of individuals were inferred to have no fullsibs among those fish genotyped (family size = 1). The median stream channel distance between pairs of individuals belonging to the same large-sized fullsib families (>3 individuals) was 100 m (range: 0–1,850 m) and 250 m (range: 0–2,350 m) in the two study sites, indicating limited dispersal at least for the size class of individuals analyzed. Using a sibship assignment method, the effective population size for the two streams was estimated at 91 (95%CI: 67–123) and 210 (95%CI: 172–259), corresponding to the ratio of effective-to-census population size of 0.06 and 0.12, respectively. Both-sex polygamy, low variation in reproductive success, and a balanced sex ratio may help maintain genetic diversity of brook trout populations with small breeder sizes persisting in headwater channel networks.

  17. A Meta-Analysis of the Metabolic Syndrome Prevalence in the Global HIV-Infected Population.

    Directory of Open Access Journals (Sweden)

    Kim A Nguyen

    Full Text Available Cardio-metabolic risk factors are of increasing concern in HIV-infected individuals, particularly with the advent of antiretroviral therapy (ART and the subsequent rise in longevity. However, the prevalence of cardio-metabolic abnormalities in this population and the differential contribution, if any, of HIV specific factors to their distribution, are poorly understood. Therefore, we conducted a systematic review and meta-analysis to estimate the global prevalence of metabolic syndrome (MS in HIV-infected populations, its variation by the different diagnostic criteria, severity of HIV infection, ART used and other major predictive characteristics.We performed a comprehensive search on major databases for original research articles published between 1998 and 2015. The pooled overall prevalence as well as by specific groups and subgroups were computed using random effects models.A total of 65 studies across five continents comprising 55094 HIV-infected participants aged 17-73 years (median age 41 years were included in the final meta-analysis. The overall prevalence of MS according to the following criteria were: ATPIII-2001:16.7% (95%CI: 14.6-18.8, IDF-2005: 18% (95%CI: 14.0-22.4, ATPIII-2004-2005: 24.6% (95%CI: 20.6-28.8, Modified ATPIII-2005: 27.9% (95%CI: 6.7-56.5, JIS-2009: 29.6% (95%CI: 22.9-36.8, and EGIR: 31.3% (95%CI: 26.8-36.0. By some MS criteria, the prevalence was significantly higher in women than in men (IDF-2005: 23.2% vs. 13.4, p = 0.030, in ART compared to non-ART users (ATPIII-2001: 18.4% vs. 11.8%, p = 0.001, and varied significantly by participant age, duration of HIV diagnosis, severity of infection, non-nucleoside reverse transcriptase inhibitors (NNRTIs use and date of study publication. Across criteria, there were significant differences in MS prevalence by sub-groups such as in men, the Americas, older publications, regional studies, younger adults, smokers, ART-naïve participants, NNRTIs users, participants with shorter

  18. Influence of habitat quality, population size, patch size, and connectivity on patch-occupancy dynamics of the middle spotted woodpecker.

    Science.gov (United States)

    Robles, Hugo; Ciudad, Carlos

    2012-04-01

    Despite extensive research on the effects of habitat fragmentation, the ecological mechanisms underlying colonization and extinction processes are poorly known, but knowledge of these mechanisms is essential to understanding the distribution and persistence of populations in fragmented habitats. We examined these mechanisms through multiseason occupancy models that elucidated patch-occupancy dynamics of Middle Spotted Woodpeckers (Dendrocopos medius) in northwestern Spain. The number of occupied patches was relatively stable from 2000 to 2010 (15-24% of 101 patches occupied every year) because extinction was balanced by recolonization. Larger and higher quality patches (i.e., higher density of oaks >37 cm dbh [diameter at breast height]) were more likely to be occupied. Habitat quality (i.e., density of large oaks) explained more variation in patch colonization and extinction than did patch size and connectivity, which were both weakly associated with probabilities of turnover. Patches of higher quality were more likely to be colonized than patches of lower quality. Populations in high-quality patches were less likely to become extinct. In addition, extinction in a patch was strongly associated with local population size but not with patch size, which means the latter may not be a good surrogate of population size in assessments of extinction probability. Our results suggest that habitat quality may be a primary driver of patch-occupancy dynamics and may increase the accuracy of models of population survival. We encourage comparisons of competing models that assess occupancy, colonization, and extinction probabilities in a single analytical framework (e.g., dynamic occupancy models) so as to shed light on the association of habitat quality and patch geometry with colonization and extinction processes in different settings and species. ©2012 Society for Conservation Biology.

  19. Estimation of the ancestral effective population sizes of African great apes under different selection regimes.

    Science.gov (United States)

    Schrago, Carlos G

    2014-08-01

    Reliable estimates of ancestral effective population sizes are necessary to unveil the population-level phenomena that shaped the phylogeny and molecular evolution of the African great apes. Although several methods have previously been applied to infer ancestral effective population sizes, an analysis of the influence of the selective regime on the estimates of ancestral demography has not been thoroughly conducted. In this study, three independent data sets under different selective regimes were used were composed to tackle this issue. The results showed that selection had a significant impact on the estimates of ancestral effective population sizes of the African great apes. The inference of the ancestral demography of African great apes was affected by the selection regime. The effects, however, were not homogeneous along the ancestral populations of great apes. The effective population size of the ancestor of humans and chimpanzees was more impacted by the selection regime when compared to the same parameter in the ancestor of humans, chimpanzees and gorillas. Because the selection regime influenced the estimates of ancestral effective population size, it is reasonable to assume that a portion of the discrepancy found in previous studies that inferred the ancestral effective population size may be attributable to the differential action of selection on the genes sampled.

  20. Mutation of HIV-1 Genomes in a Clinical Population Treated with the Mutagenic Nucleoside KP1461

    OpenAIRE

    Mullins, James I.; Heath, Laura; Hughes, James P.; Kicha, Jessica; Styrchak, Sheila; Wong, Kim G.; Rao, Ushnal; Hansen, Alexis; Harris, Kevin S.; Laurent, Jean-Pierre; Li, Deyu; Simpson, Jeffrey H.; Essigmann, John M.; Loeb, Lawrence A.; Parkins, Jeffrey

    2011-01-01

    The deoxycytidine analog KP1212, and its prodrug KP1461, are prototypes of a new class of antiretroviral drugs designed to increase viral mutation rates, with the goal of eventually causing the collapse of the viral population. Here we present an extensive analysis of viral sequences from HIV-1 infected volunteers from the first "mechanism validation" phase II clinical trial of a mutagenic base analog in which individuals previously treated with antiviral drugs received 1600 mg of KP1461 twic...

  1. Trends in cigarette smoking among adults with HIV compared with the general adult population, United States - 2009-2014.

    Science.gov (United States)

    Frazier, Emma L; Sutton, Madeline Y; Brooks, John T; Shouse, R Luke; Weiser, John

    2018-06-01

    Smoking increases HIV-related and non-HIV-related morbidity and mortality for persons with HIV infection. We estimated changes in cigarette smoking among adults with HIV and adults in the general U.S. population from 2009 to 2014 to inform HIV smoking cessation programs. Among HIV-positive adults, rates of current smoking declined from 37.6% (confidence interval [CI]: 34.7-40.6) in 2009 to 33.6% (CI: 29.8-37.8) in 2014. Current smoking among U.S. adults declined from 20.6% (CI: 19.9-21.3) in 2009 to 16.8% (CI: 16.2-17.4) in 2014. HIV-positive adults in care were significantly more likely to be current smokers compared with the general U.S. population; they were also less likely to quit smoking. For both HIV-positive adults in care and the general population, disparities were noted by racial/ethnic, educational level, and poverty-level subgroups. For most years, non-Hispanic blacks, those with less than high school education, and those living below poverty level were more likely to be current smokers and less likely to quit smoking compared with non-Hispanic whites, those with greater than high school education, and those living above poverty level, respectively. To decrease smoking-related causes of illness and death and to decrease HIV-related disparities, smoking cessation interventions are vital as part of routine care with HIV-positive persons. Clinicians who care for HIV-positive persons who smoke should utilize opportunities to discuss and implement smoking cessation strategies during routine clinical visits. Published by Elsevier Inc.

  2. 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.

  3. Population-based biomedical sexually transmitted infection control interventions for reducing HIV infection.

    Science.gov (United States)

    Ng, Brian E; Butler, Lisa M; Horvath, Tara; Rutherford, George W

    2011-03-16

    The transmission of sexually transmitted infections (STIs) is closely related to the sexual transmission of human immunodeficiency virus (HIV). Similar risk behaviours, such as frequent unprotected intercourse with different partners, place people at high risk of HIV and STIs, and there is clear evidence that many STIs increase the likelihood of HIV transmission. STI control, especially at the population or community level, may have the potential to contribute substantially to HIV prevention.This is an update of an existing Cochrane review. The review's search methods were updated and its inclusion and exclusion criteria modified so that the focus would be on one well-defined outcome. This review now focuses explicitly on population-based biomedical interventions for STI control, with change in HIV incidence being an outcome necessary for a study's inclusion. To determine the impact of population-based biomedical STI interventions on the incidence of HIV infection. We searched PubMed, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science/Social Science, PsycINFO, and Literatura Latino Americana e do Caribe em Ciências da Saúde (LILACS), for the period of 1 January1980 - 16 August 2010. We initially identified 6003 articles and abstracts. After removing 776 duplicates, one author (TH) removed an additional 3268 citations that were clearly irrelevant. Rigorously applying the inclusion criteria, three authors then independently screened the remaining 1959 citations and abstracts. Forty-six articles were chosen for full-text scrutiny by two authors. Ultimately, four studies were included in the review.We also searched the Aegis database of conference abstracts, which includes the Conference on Retroviruses and Opportunistic Infections (CROI), the International AIDS Conference (IAC), and International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention (IAS) meetings from their inception dates (1993, 1985 and

  4. Population-based resequencing of experimentally evolved populations reveals the genetic basis of body size variation in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Thomas L Turner

    2011-03-01

    Full Text Available Body size is a classic quantitative trait with evolutionarily significant variation within many species. Locating the alleles responsible for this variation would help understand the maintenance of variation in body size in particular, as well as quantitative traits in general. However, successful genome-wide association of genotype and phenotype may require very large sample sizes if alleles have low population frequencies or modest effects. As a complementary approach, we propose that population-based resequencing of experimentally evolved populations allows for considerable power to map functional variation. Here, we use this technique to investigate the genetic basis of natural variation in body size in Drosophila melanogaster. Significant differentiation of hundreds of loci in replicate selection populations supports the hypothesis that the genetic basis of body size variation is very polygenic in D. melanogaster. Significantly differentiated variants are limited to single genes at some loci, allowing precise hypotheses to be formed regarding causal polymorphisms, while other significant regions are large and contain many genes. By using significantly associated polymorphisms as a priori candidates in follow-up studies, these data are expected to provide considerable power to determine the genetic basis of natural variation in body size.

  5. Recombination gives a new insight in the effective population size and the history of the old world human populations.

    Science.gov (United States)

    Melé, Marta; Javed, Asif; Pybus, Marc; Zalloua, Pierre; Haber, Marc; Comas, David; Netea, Mihai G; Balanovsky, Oleg; Balanovska, Elena; Jin, Li; Yang, Yajun; Pitchappan, R M; Arunkumar, G; Parida, Laxmi; Calafell, Francesc; Bertranpetit, Jaume

    2012-01-01

    The information left by recombination in our genomes can be used to make inferences on our recent evolutionary history. Specifically, the number of past recombination events in a population sample is a function of its effective population size (Ne). We have applied a method, Identifying Recombination in Sequences (IRiS), to detect specific past recombination events in 30 Old World populations to infer their Ne. We have found that sub-Saharan African populations have an Ne that is approximately four times greater than those of non-African populations and that outside of Africa, South Asian populations had the largest Ne. We also observe that the patterns of recombinational diversity of these populations correlate with distance out of Africa if that distance is measured along a path crossing South Arabia. No such correlation is found through a Sinai route, suggesting that anatomically modern humans first left Africa through the Bab-el-Mandeb strait rather than through present Egypt.

  6. High-resolution deep sequencing reveals biodiversity, population structure, and persistence of HIV-1 quasispecies within host ecosystems

    Directory of Open Access Journals (Sweden)

    Yin Li

    2012-12-01

    Full Text Available Abstract Background Deep sequencing provides the basis for analysis of biodiversity of taxonomically similar organisms in an environment. While extensively applied to microbiome studies, population genetics studies of viruses are limited. To define the scope of HIV-1 population biodiversity within infected individuals, a suite of phylogenetic and population genetic algorithms was applied to HIV-1 envelope hypervariable domain 3 (Env V3 within peripheral blood mononuclear cells from a group of perinatally HIV-1 subtype B infected, therapy-naïve children. Results Biodiversity of HIV-1 Env V3 quasispecies ranged from about 70 to 270 unique sequence clusters across individuals. Viral population structure was organized into a limited number of clusters that included the dominant variants combined with multiple clusters of low frequency variants. Next generation viral quasispecies evolved from low frequency variants at earlier time points through multiple non-synonymous changes in lineages within the evolutionary landscape. Minor V3 variants detected as long as four years after infection co-localized in phylogenetic reconstructions with early transmitting viruses or with subsequent plasma virus circulating two years later. Conclusions Deep sequencing defines HIV-1 population complexity and structure, reveals the ebb and flow of dominant and rare viral variants in the host ecosystem, and identifies an evolutionary record of low-frequency cell-associated viral V3 variants that persist for years. Bioinformatics pipeline developed for HIV-1 can be applied for biodiversity studies of virome populations in human, animal, or plant ecosystems.

  7. HIV/AIDS in mid-sized cities in Senegal: From individual to place-based vulnerability.

    Science.gov (United States)

    Drame, Fatou Maria; Foley, Ellen E

    2015-05-01

    In Senegal, recent data indicates that the HIV epidemic is increasingly driven by concurrent sexual partners among men and women in stable relationships. In order to respond to this changing epidemiological profile in Senegal, multi-lateral and national AIDS actors require information about these emerging trends in unstudied populations. To that end, this study has several objectives, first, to assess local dynamics of sexual behaviors among individuals at popular socializing venues in areas at increased risk of HIV transmission; and then to examine how particular venues may influence risks of HIV transmission. In 2013 we collected data at 314 venues in 10 cities in Senegal using PLACE methodology. These venues were listed with collaboration of 374 community informants. They are places where commercial sex workers, MSM, and individuals who are not part of any identified risk group socialize and meet new sexual partners. We conducted 2600 interviews at the 96 most popular venues. A significant portion of the sample reports buying or selling sex and the majority engaged in behavior considered high-risk for transmitting sexual infections. Almost a quarter of patrons interviewed in venues were young people aged 15-24 years. Types of venues described were very diverse. Half of them were venues (n = 156) where sex workers could be solicited and almost a third were venues where MSM could meet male partners (n = 90). The study showed existing pockets of vulnerability to HIV in Thies, Bignona or Saly that are not evident from aggregate HIV data. These early findings suggest links between risky behaviors and type of venue on the one hand and type of city on the other hand. Finally, these findings offer complementary insight to existing studies of HIV vulnerability in Senegal and support a case for venue-based interventions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. 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.

  9. Effective size of density-dependent two-sex populations: the effect of mating systems.

    Science.gov (United States)

    Myhre, A M; Engen, S; SAEther, B-E

    2017-08-01

    Density dependence in vital rates is a key feature affecting temporal fluctuations of natural populations. This has important implications for the rate of random genetic drift. Mating systems also greatly affect effective population sizes, but knowledge of how mating system and density regulation interact to affect random genetic drift is poor. Using theoretical models and simulations, we compare N e in short-lived, density-dependent animal populations with different mating systems. We study the impact of a fluctuating, density-dependent sex ratio and consider both a stable and a fluctuating environment. We find a negative relationship between annual N e /N and adult population size N due to density dependence, suggesting that loss of genetic variation is reduced at small densities. The magnitude of this decrease was affected by mating system and life history. A male-biased, density-dependent sex ratio reduces the rate of genetic drift compared to an equal, density-independent sex ratio, but a stochastic change towards male bias reduces the N e /N ratio. Environmental stochasticity amplifies temporal fluctuations in population size and is thus vital to consider in estimation of effective population sizes over longer time periods. Our results on the reduced loss of genetic variation at small densities, particularly in polygamous populations, indicate that density regulation may facilitate adaptive evolution at small population sizes. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  10. Spatial clustering of all-cause and HIV-related mortality in a rural South African population (2000-2006.

    Directory of Open Access Journals (Sweden)

    Elias Namosha

    Full Text Available Sub-Saharan Africa bears a disproportionate burden of HIV infection. Knowledge of the spatial distribution of HIV outcomes is vital so that appropriate public health interventions can be directed at locations most in need. In this regard, spatial clustering analysis of HIV-related mortality events has not been performed in a rural sub-Saharan African setting.Kulldorff's spatial scan statistic was used to identify HIV-related and all-cause mortality clusters (p<0.05 in a population-based demographic surveillance survey in rural KwaZulu Natal, South Africa (2000-2006. The analysis was split pre (2000-2003 and post (2004-2006 rollout of antiretroviral therapy, respectively. Between 2000-2006 a total of 86,175 resident individuals ≥15 years of age were under surveillance and 5,875 deaths were recorded (of which 2,938 were HIV-related over 343,060 person-years of observation (crude all-cause mortality rate 17.1/1000. During both time periods a cluster of high HIV-related (RR = 1.46/1.51, p = 0.001 and high all-cause mortality (RR = 1.35/1.38, p = 0.001 was identified in peri-urban communities near the National Road. A consistent low-risk cluster was detected in the urban township in both time periods (RR = 0.60/0.39, p = 0.003/0.005 and in the first time period (2000-2003 a large cluster of low HIV-related and all-cause mortality in a remote rural area was identified.HIV-related and all-cause mortality exhibit strong spatial clustering tendencies in this population. Highest HIV-related mortality and all-cause mortality occurred in the peri-urban communities along the National Road and was lowest in the urban township and remote rural communities. The geography of HIV-related mortality corresponded closely to the geography of HIV prevalence, with the notable exception of the urban township where high HIV-related mortality would have been expected on the basis of the high HIV prevalence. Our results suggest that HIV treatment

  11. Fitness decline under osmotic stress in Caenorhabditis elegans populations subjected to spontaneous mutation accumulation at varying population sizes.

    Science.gov (United States)

    Katju, Vaishali; Packard, Lucille B; Keightley, Peter D

    2018-04-01

    The consequences of mutations for population fitness depends on their individual selection coefficients and the effective population size. An earlier study of Caenorhabditis elegans spontaneous mutation accumulation lines evolved for 409 generations at three population sizes found that N e   = 1 populations declined significantly in fitness whereas the fitness of larger populations (N e   = 5, 50) was indistinguishable from the ancestral control under benign conditions. To test if larger MA populations harbor a load of cryptic deleterious mutations that are obscured under benign laboratory conditions, we measured fitness under osmotic stress via exposure to hypersaline conditions. The fitness of N e   = 1 lines exhibited a further decline under osmotic stress compared to benign conditions. However, the fitness of larger populations remained indistinguishable from that of the ancestral control. The average effects of deleterious mutations in N e   = 1 lines were estimated to be 22% for productivity and 14% for survivorship, exceeding values previously detected under benign conditions. Our results suggest that fitness decline is due to large effect mutations that are rapidly removed via selection even in small populations, with implications for conservation practices. Genetic stochasticity may not be as potent and immediate a threat to the persistence of small populations as other demographic and environmental stochastic factors. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

  12. Rate of inbreeding and effective population size in four major South ...

    African Journals Online (AJOL)

    huis

    Keywords: Dairy cattle, genetic diversity, pedigree analysis ... inbreeding and effective population sizes for the four major South African ... breeding programs and therefore L was computed as an average of generation intervals for the four.

  13. Ontogenetic niche shifts and evolutionary branching in size-structured populations

    NARCIS (Netherlands)

    Claessen, D.; Dieckmann, U.

    2002-01-01

    There are many examples of size-structured populations where individuals sequentially exploit several niches in the course of their life history. Efficient exploitation of such ontogenetic niches generally requires specific morphological adaptations. Here, we study the evolutionary implications of

  14. Factors determining the average body size of geographically separated Arctodiaptomus salinus (Daday, 1885) populations

    OpenAIRE

    Anufriieva, Elena V.; Shadrin, Nickolai V.

    2014-01-01

    Arctodiaptomus salinus inhabits water bodies across Eurasia and North Africa. Based on our own data and that from the literature, we analyzed the influences of several factors on the intra- and inter-population variability of this species. A strong negative linear correlation between temperature and average body size in the Crimean and African populations was found, in which the parameters might be influenced by salinity. Meanwhile, asignificant negative correlation between female body size a...

  15. Human papillomavirus prevalence and type distribution in 3603 HIV-positive and HIV-negative women in the general population of Tanzania

    DEFF Research Database (Denmark)

    Dartell, Myassa Arkam; Rasch, Vibeke; Kahesa, Crispin

    2012-01-01

    The aim of the Prevention of Cervical Cancer in Tanzania (PROTECT) study is to assess the prevalence of oncogenic human papillomavirus (HPV) and to determine the type distribution among women in the general population according to human immunodeficiency virus (HIV) status, in preparation for a po......The aim of the Prevention of Cervical Cancer in Tanzania (PROTECT) study is to assess the prevalence of oncogenic human papillomavirus (HPV) and to determine the type distribution among women in the general population according to human immunodeficiency virus (HIV) status, in preparation...

  16. A 10-year population based study of 'opt-out' HIV testing of tuberculosis patients in Alberta, Canada: national implications.

    Directory of Open Access Journals (Sweden)

    Richard Long

    Full Text Available Compliance with the recommendation that all tuberculosis (TB patients be tested for human immunodeficiency virus (HIV has not yet been achieved in Canada or globally.The experience of "opt-out" HIV testing of TB patients in the Province of Alberta, Canada is described over a 10-year period, 2003-2012. Testing rates are reported before and after the introduction of the "opt-out" approach. Risk factors for HIV seropositivity are described and demographic, clinical and laboratory characteristics of TB patients who were newly diagnosed versus previously diagnosed with HIV are compared. Genotypic clusters, defined as groups of two or more cases whose isolates of Mycobacterium tuberculosis had identical DNA fingerprints over the 10-year period or within 2 years of one another, were analyzed for their ability to predict HIV co-infection.HIV testing rates were 26% before and 90% after the introduction of "opt-out" testing. During the "opt-out" testing years those 64 years of age at diagnosis were less likely to have been tested. In those tested the prevalence of HIV was 5.6%. In the age group 15-64 years, risk factors for HIV were: age (35-64 years, Canadian-born Aboriginal or foreign-born sub-Saharan African origin, and combined respiratory and non-respiratory disease. Compared to TB patients previously known to be HIV positive, TB patients newly discovered to be HIV positive had more advanced HIV disease (lower CD4 counts; higher viral loads at diagnosis. Large cluster size was associated with Aboriginal ancestry. Cluster size predicted HIV co-infection in Aboriginal peoples when clusters included all cases reported over 10 years but not when clusters included cases reported within 2 years of one another."Opt-out" HIV testing of TB patients is effective and well received. Universal HIV testing of TB patients (>80% of patients tested has immediate (patients and longer-term (TB/HIV program planning benefits.

  17. Interpreting surveys to estimate the size of the monarch butterfly population: Pitfalls and prospects.

    Directory of Open Access Journals (Sweden)

    John M Pleasants

    Full Text Available To assess the change in the size of the eastern North American monarch butterfly summer population, studies have used long-term data sets of counts of adult butterflies or eggs per milkweed stem. Despite the observed decline in the monarch population as measured at overwintering sites in Mexico, these studies found no decline in summer counts in the Midwest, the core of the summer breeding range, leading to a suggestion that the cause of the monarch population decline is not the loss of Midwest agricultural milkweeds but increased mortality during the fall migration. Using these counts to estimate population size, however, does not account for the shift of monarch activity from agricultural fields to non-agricultural sites over the past 20 years, as a result of the loss of agricultural milkweeds due to the near-ubiquitous use of glyphosate herbicides. We present the counter-hypotheses that the proportion of the monarch population present in non-agricultural habitats, where counts are made, has increased and that counts reflect both population size and the proportion of the population observed. We use data on the historical change in the proportion of milkweeds, and thus monarch activity, in agricultural fields and non-agricultural habitats to show why using counts can produce misleading conclusions about population size. We then separate out the shifting proportion effect from the counts to estimate the population size and show that these corrected summer monarch counts show a decline over time and are correlated with the size of the overwintering population. In addition, we present evidence against the hypothesis of increased mortality during migration. The milkweed limitation hypothesis for monarch decline remains supported and conservation efforts focusing on adding milkweeds to the landscape in the summer breeding region have a sound scientific basis.

  18. [Validation of an HIV and other sexually transmitted infections knowledge scale in an adolescent population].

    Science.gov (United States)

    Espada, José Pedro; Guillén-Riquelme, Alejandro; Morales, Alexandra; Orgilés, Mireia; Sierra, Juan Carlos

    2014-12-01

    The objective of this research is to determine the validity and reliability of a questionnaire designed to specifically assess the knowledge of HIV and other sexually transmitted infections in a Spanish adolescent population. Cross-sectional study for the validation of a questionnaire. A total of 17 schools in five Spanish provinces. A total of 1,570 adolescent schoolchildren between 13 and 17 years old. A pool of 40 items relating to knowledge about HIV and other sexually transmitted infections was established. This pool was analyzed by an expert panel. It was then administered to a pilot group with the same demographic characteristics of the sample, to ensure comprehension. Item analysis, internal consistency, test/retest and exploratory factorial analysis. A factor analysis was performed, in which five factors that explained 46% of the total variance were retained: general knowledge about HIV, condom as a protective method, routes of HIV transmission, the prevention of HIV, and other sexually transmitted infections. Reliability measures ranged from 0.66 to 0.88. The test-retest correlation was 0.59. There were gender differences in the knowledge of infections. These factors have adequate internal consistency and acceptable test-retest correlation. Theoretically, these factors fit properly with the content of the items. The factors have a moderate relationship, indicating that a high degree of knowledge about an aspect, but not a guarantee of general knowledge. The availability of a questionnaire to assess knowledge of sexually transmitted infections is helpful to evaluate prevention programs. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  19. Effects of habitat size and quality on equilibrium density and extinction time of Sorex araneus populations

    NARCIS (Netherlands)

    Klok, C.; Roos, de A.M.

    1998-01-01

    1. The effects of changes in habitat size and quality on the expected population density and the expected time to extinction of Sorex araneus are studied by means of mathematical models that incorporate demographic stochasticity. 2. Habitat size is characterized by the number of territories, while

  20. Confidence intervals for population allele frequencies: the general case of sampling from a finite diploid population of any size.

    Science.gov (United States)

    Fung, Tak; Keenan, Kevin

    2014-01-01

    The estimation of population allele frequencies using sample data forms a central component of studies in population genetics. These estimates can be used to test hypotheses on the evolutionary processes governing changes in genetic variation among populations. However, existing studies frequently do not account for sampling uncertainty in these estimates, thus compromising their utility. Incorporation of this uncertainty has been hindered by the lack of a method for constructing confidence intervals containing the population allele frequencies, for the general case of sampling from a finite diploid population of any size. In this study, we address this important knowledge gap by presenting a rigorous mathematical method to construct such confidence intervals. For a range of scenarios, the method is used to demonstrate that for a particular allele, in order to obtain accurate estimates within 0.05 of the population allele frequency with high probability (> or = 95%), a sample size of > 30 is often required. This analysis is augmented by an application of the method to empirical sample allele frequency data for two populations of the checkerspot butterfly (Melitaea cinxia L.), occupying meadows in Finland. For each population, the method is used to derive > or = 98.3% confidence intervals for the population frequencies of three alleles. These intervals are then used to construct two joint > or = 95% confidence regions, one for the set of three frequencies for each population. These regions are then used to derive a > or = 95%% confidence interval for Jost's D, a measure of genetic differentiation between the two populations. Overall, the results demonstrate the practical utility of the method with respect to informing sampling design and accounting for sampling uncertainty in studies of population genetics, important for scientific hypothesis-testing and also for risk-based natural resource management.

  1. Confidence intervals for population allele frequencies: the general case of sampling from a finite diploid population of any size.

    Directory of Open Access Journals (Sweden)

    Tak Fung

    Full Text Available The estimation of population allele frequencies using sample data forms a central component of studies in population genetics. These estimates can be used to test hypotheses on the evolutionary processes governing changes in genetic variation among populations. However, existing studies frequently do not account for sampling uncertainty in these estimates, thus compromising their utility. Incorporation of this uncertainty has been hindered by the lack of a method for constructing confidence intervals containing the population allele frequencies, for the general case of sampling from a finite diploid population of any size. In this study, we address this important knowledge gap by presenting a rigorous mathematical method to construct such confidence intervals. For a range of scenarios, the method is used to demonstrate that for a particular allele, in order to obtain accurate estimates within 0.05 of the population allele frequency with high probability (> or = 95%, a sample size of > 30 is often required. This analysis is augmented by an application of the method to empirical sample allele frequency data for two populations of the checkerspot butterfly (Melitaea cinxia L., occupying meadows in Finland. For each population, the method is used to derive > or = 98.3% confidence intervals for the population frequencies of three alleles. These intervals are then used to construct two joint > or = 95% confidence regions, one for the set of three frequencies for each population. These regions are then used to derive a > or = 95%% confidence interval for Jost's D, a measure of genetic differentiation between the two populations. Overall, the results demonstrate the practical utility of the method with respect to informing sampling design and accounting for sampling uncertainty in studies of population genetics, important for scientific hypothesis-testing and also for risk-based natural resource management.

  2. Variation of Body Size in Rice Water Weevil (Coleoptera: Curculionidae) and Its Associations with Population Biology

    OpenAIRE

    Huang, Yunshan; Ao, Yan; Jiang, Mingxing; Way, Michael O

    2018-01-01

    Abstract Life history characteristics help us to determine the ability of invasive species to establish and thrive in an exotic environment. However, so far, there have been very few reports concerning geographic variation in the body size of invasive insects and the associations between body size variation and population biology. In this study, we surveyed the geographic variation in body size of an invasive agricultural pest, the rice water weevil Lissorhoptrus oryzophilus Kuschel (Coleopte...

  3. Temporal variation in population size of European bird species: effects of latitude and marginality of distribution.

    Directory of Open Access Journals (Sweden)

    José J Cuervo

    Full Text Available In the Northern Hemisphere, global warming has been shown to affect animal populations in different ways, with southern populations in general suffering more from increased temperatures than northern populations of the same species. However, southern populations are also often marginal populations relative to the entire breeding range, and marginality may also have negative effects on populations. To disentangle the effects of latitude (possibly due to global warming and marginality on temporal variation in population size, we investigated European breeding bird species across a latitudinal gradient. Population size estimates were regressed on years, and from these regressions we obtained the slope (a proxy for population trend and the standard error of the estimate (SEE (a proxy for population fluctuations. The possible relationships between marginality or latitude on one hand and slopes or SEE on the other were tested among populations within species. Potentially confounding factors such as census method, sampling effort, density-dependence, habitat fragmentation and number of sampling years were controlled statistically. Population latitude was positively related to regression slopes independent of marginality, with more positive slopes (i.e., trends in northern than in southern populations. The degree of marginality was positively related to SEE independent of latitude, with marginal populations showing larger SEE (i.e., fluctuations than central ones. Regression slopes were also significantly related to our estimate of density-dependence and SEE was significantly affected by the census method. These results are consistent with a scenario in which southern and northern populations of European bird species are negatively affected by marginality, with southern populations benefitting less from global warming than northern populations, thus potentially making southern populations more vulnerable to extinction.

  4. Coevolving parasites and population size shape the evolution of mating behaviour

    Directory of Open Access Journals (Sweden)

    Kerstes Niels AG

    2013-02-01

    Full Text Available Abstract Background Coevolution with parasites and population size are both expected to influence the evolution of mating rates. To gain insights into the interaction between these dual selective factors, we used populations from a coevolution experiment with the red flour beetle, Tribolium castaneum, and its microsporidian parasite, Nosema whitei. We maintained each experimental population at two different population sizes. We assayed the mating behaviour of both males and females from coevolved and paired non-coevolved control populations after 24 generations of coevolution with parasites. Results Males from large, coevolved populations (i.e. ancestors were exposed to parasites showed a reduced eagerness to mate compared to males from large, non-coevolved populations. But in small populations, coevolution did not lead to decreased male mating rates. Coevolved females from both large and small populations appeared to be more willing to accept mating than non-coevolved females. Conclusions This study provides unique, experimental insights into the combined roles of coevolving parasites and population size on the evolution of mating rate. Furthermore, we find that males and females respond differently to the same environmental conditions. Our results show that parasites can be key determinants of the sexual behaviour of their hosts.

  5. Population Size Estimation of Gay and Bisexual Men and Other Men Who Have Sex With Men Using Social Media-Based Platforms.

    Science.gov (United States)

    Baral, Stefan; Turner, Rachael M; Lyons, Carrie E; Howell, Sean; Honermann, Brian; Garner, Alex; Hess, Robert; Diouf, Daouda; Ayala, George; Sullivan, Patrick S; Millett, Greg

    2018-02-08

    Gay, bisexual, and other cisgender men who have sex with men (GBMSM) are disproportionately affected by the HIV pandemic. Traditionally, GBMSM have been deemed less relevant in HIV epidemics in low- and middle-income settings where HIV epidemics are more generalized. This is due (in part) to how important population size estimates regarding the number of individuals who identify as GBMSM are to informing the development and monitoring of HIV prevention, treatment, and care programs and coverage. However, pervasive stigma and criminalization of same-sex practices and relationships provide a challenging environment for population enumeration, and these factors have been associated with implausibly low or absent size estimates of GBMSM, thereby limiting knowledge about the dynamics of HIV transmission and the implementation of programs addressing GBMSM. This study leverages estimates of the number of members of a social app geared towards gay men (Hornet) and members of Facebook using self-reported relationship interests in men, men and women, and those with at least one reported same-sex interest. Results were categorized by country of residence to validate official size estimates of GBMSM in 13 countries across five continents. Data were collected through the Hornet Gay Social Network and by using an a priori determined framework to estimate the numbers of Facebook members with interests associated with GBMSM in South Africa, Ghana, Nigeria, Senegal, Côte d'Ivoire, Mauritania, The Gambia, Lebanon, Thailand, Malaysia, Brazil, Ukraine, and the United States. These estimates were compared with the most recent Joint United Nations Programme on HIV/AIDS (UNAIDS) and national estimates across 143 countries. The estimates that leveraged social media apps for the number of GBMSM across countries are consistently far higher than official UNAIDS estimates. Using Facebook, it is also feasible to assess the numbers of GBMSM aged 13-17 years, which demonstrate similar

  6. Experimental design and estimation of growth rate distributions in size-structured shrimp populations

    International Nuclear Information System (INIS)

    Banks, H T; Davis, Jimena L; Ernstberger, Stacey L; Hu, Shuhua; Artimovich, Elena; Dhar, Arun K

    2009-01-01

    We discuss inverse problem results for problems involving the estimation of probability distributions using aggregate data for growth in populations. We begin with a mathematical model describing variability in the early growth process of size-structured shrimp populations and discuss a computational methodology for the design of experiments to validate the model and estimate the growth-rate distributions in shrimp populations. Parameter-estimation findings using experimental data from experiments so designed for shrimp populations cultivated at Advanced BioNutrition Corporation are presented, illustrating the usefulness of mathematical and statistical modeling in understanding the uncertainty in the growth dynamics of such populations

  7. SOCIO-DEMOGRAPHIC FACTORS INFLUENCING FAMILY SIZE AMONG RURAL POPULATION OF DISTRICT NAINITAL, UTTARAKHAND

    Directory of Open Access Journals (Sweden)

    Sanjay Pandey

    2012-12-01

    Full Text Available Background: India is the second most populous country in the world. A decline in its population growth rate has been shown amounting to during the last decades. The decline in the family size is important step towards population stabilization for our country. The status of family size is related to various demographic, socio-economic, cultural factors and attitude towards use of family planning methods. Objective: To assess the relationship of family size with socio-economic factors and effect of contraceptive use. Methodology: A cross sectional house to house survey to know the family size and socio-demographic was conducted in the adopted villages of field practice area. The study subjects are the married women of reproductive age group (15-49 years. Results: About half (44.9% of respondents were aged more than 35 years and only (0.9% were < 19 years. The family size in our study was 2.55. About 54.5% of respondents have family size d" 2. About two-third of families (65% with size less than or equals to two were of nuclear type. Education level of family has significant relationship with small family size. About 90% of the respondents and their spouse of family size two or less were literate. A significant association was found between occupation of the spouse and family size. The spouses of the respondents with family size more than two were mainly engaged in agriculture (29.7% and as labourer (38.5%. Among the families with family size of more than two, majority were from middle (81% and lower (14.9% class. There is no significant effect of use of contraceptives on the family size.

  8. SOCIO-DEMOGRAPHIC FACTORS INFLUENCING FAMILY SIZE AMONG RURAL POPULATION OF DISTRICT NAINITAL, UTTARAKHAND

    Directory of Open Access Journals (Sweden)

    Sanjay Pandey

    2013-01-01

    Full Text Available Background: India is the second most populous country in the world. A decline in its population growth rate has been shown amounting to during the last decades. The decline in the family size is important step towards population stabilization for our country. The status of family size is related to various demographic, socio-economic, cultural factors and attitude towards use of family planning methods. Objective: To assess the relationship of family size with socio-economic factors and effect of contraceptive use. Methodology: A cross sectional house to house survey to know the family size and socio-demographic was conducted in the adopted villages of field practice area. The study subjects are the married women of reproductive age group (15-49 years. Results: About half (44.9% of respondents were aged more than 35 years and only (0.9% were < 19 years. The family size in our study was 2.55. About 54.5% of respondents have family size d" 2. About two-third of families (65% with size less than or equals to two were of nuclear type. Education level of family has significant relationship with small family size. About 90% of the respondents and their spouse of family size two or less were literate. A significant association was found between occupation of the spouse and family size. The spouses of the respondents with family size more than two were mainly engaged in agriculture (29.7% and as labourer (38.5%. Among the families with family size of more than two, majority were from middle (81% and lower (14.9% class. There is no significant effect of use of contraceptives on the family size.

  9. Pronounced lipoatrophy in HIV-infected men receiving HAART for more than 6 years compared with the background population

    DEFF Research Database (Denmark)

    Hansen, AB; Lindegaard, B; Obel, N

    2006-01-01

    OBJECTIVES: To establish the prevalence and quantify the severity of body fat redistribution and dyslipidaemia in HIV-infected men after long-term highly active antiretroviral therapy (HAART) compared with the background population. METHODS: In a cross-sectional study, we included 87 HIV......-infected men who had received HAART for at least 6 years and 34 HIV-negative men. Regional body composition was assessed using dual-energy X-ray absorptiometry. Fasting metabolic parameters were obtained. Associations between regional body fat distribution and metabolic parameters were evaluated. RESULTS: HIV......-infected patients and controls did not differ with regard to height and lean body mass. Compared with controls, HIV-infected men had reduced total fat mass (median 12.3 versus 19.2 kg, P

  10. Factors determining the average body size of geographically separated Arctodiaptomus salinus (Daday, 1885) populations.

    Science.gov (United States)

    Anufriieva, Elena V; Shadrin, Nickolai V

    2014-03-01

    Arctodiaptomus salinus inhabits water bodies across Eurasia and North Africa. Based on our own data and that from the literature, we analyzed the influences of several factors on the intra- and inter-population variability of this species. A strong negative linear correlation between temperature and average body size in the Crimean and African populations was found, in which the parameters might be influenced by salinity. Meanwhile, a significant negative correlation between female body size and the altitude of habitats was found by comparing body size in populations from different regions. Individuals from environments with highly varying abiotic parameters, e.g. temporary reservoirs, had a larger body size than individuals from permanent water bodies. The changes in average body mass in populations were at 11.4 times, whereas, those in individual metabolic activities were at 6.2 times. Moreover, two size groups of A. salinus in the Crimean and the Siberian lakes were observed. The ratio of female length to male length fluctuated between 1.02 and 1.30. The average size of A. salinus in populations and its variations were determined by both genetic and environmental factors. However, the parities of these factors were unequal in either spatial or temporal scales.

  11. HIV/AIDS Coinfection

    Science.gov (United States)

    ... Coinfection Hepatitis C Coinfection HIV/AIDS Coinfection HIV/AIDS Coinfection Approximately 10% of the HIV-infected population ... Control and Prevention website to learn about HIV/AIDS and Viral Hepatitis guidelines and resources. Home About ...

  12. Slow-fast stochastic diffusion dynamics and quasi-stationarity for diploid populations with varying size.

    Science.gov (United States)

    Coron, Camille

    2016-01-01

    We are interested in the long-time behavior of a diploid population with sexual reproduction and randomly varying population size, characterized by its genotype composition at one bi-allelic locus. The population is modeled by a 3-dimensional birth-and-death process with competition, weak cooperation and Mendelian reproduction. This stochastic process is indexed by a scaling parameter K that goes to infinity, following a large population assumption. When the individual birth and natural death rates are of order K, the sequence of stochastic processes indexed by K converges toward a new slow-fast dynamics with variable population size. We indeed prove the convergence toward 0 of a fast variable giving the deviation of the population from quasi Hardy-Weinberg equilibrium, while the sequence of slow variables giving the respective numbers of occurrences of each allele converges toward a 2-dimensional diffusion process that reaches (0,0) almost surely in finite time. The population size and the proportion of a given allele converge toward a Wright-Fisher diffusion with stochastically varying population size and diploid selection. We insist on differences between haploid and diploid populations due to population size stochastic variability. Using a non trivial change of variables, we study the absorption of this diffusion and its long time behavior conditioned on non-extinction. In particular we prove that this diffusion starting from any non-trivial state and conditioned on not hitting (0,0) admits a unique quasi-stationary distribution. We give numerical approximations of this quasi-stationary behavior in three biologically relevant cases: neutrality, overdominance, and separate niches.

  13. Towards a theory of cortical columns: From spiking neurons to interacting neural populations of finite size

    Science.gov (United States)

    Gerstner, Wulfram

    2017-01-01

    Neural population equations such as neural mass or field models are widely used to study brain activity on a large scale. However, the relation of these models to the properties of single neurons is unclear. Here we derive an equation for several interacting populations at the mesoscopic scale starting from a microscopic model of randomly connected generalized integrate-and-fire neuron models. Each population consists of 50–2000 neurons of the same type but different populations account for different neuron types. The stochastic population equations that we find reveal how spike-history effects in single-neuron dynamics such as refractoriness and adaptation interact with finite-size fluctuations on the population level. Efficient integration of the stochastic mesoscopic equations reproduces the statistical behavior of the population activities obtained from microscopic simulations of a full spiking neural network model. The theory describes nonlinear emergent dynamics such as finite-size-induced stochastic transitions in multistable networks and synchronization in balanced networks of excitatory and inhibitory neurons. The mesoscopic equations are employed to rapidly integrate a model of a cortical microcircuit consisting of eight neuron types, which allows us to predict spontaneous population activities as well as evoked responses to thalamic input. Our theory establishes a general framework for modeling finite-size neural population dynamics based on single cell and synapse parameters and offers an efficient approach to analyzing cortical circuits and computations. PMID:28422957

  14. Towards a theory of cortical columns: From spiking neurons to interacting neural populations of finite size.

    Science.gov (United States)

    Schwalger, Tilo; Deger, Moritz; Gerstner, Wulfram

    2017-04-01

    Neural population equations such as neural mass or field models are widely used to study brain activity on a large scale. However, the relation of these models to the properties of single neurons is unclear. Here we derive an equation for several interacting populations at the mesoscopic scale starting from a microscopic model of randomly connected generalized integrate-and-fire neuron models. Each population consists of 50-2000 neurons of the same type but different populations account for different neuron types. The stochastic population equations that we find reveal how spike-history effects in single-neuron dynamics such as refractoriness and adaptation interact with finite-size fluctuations on the population level. Efficient integration of the stochastic mesoscopic equations reproduces the statistical behavior of the population activities obtained from microscopic simulations of a full spiking neural network model. The theory describes nonlinear emergent dynamics such as finite-size-induced stochastic transitions in multistable networks and synchronization in balanced networks of excitatory and inhibitory neurons. The mesoscopic equations are employed to rapidly integrate a model of a cortical microcircuit consisting of eight neuron types, which allows us to predict spontaneous population activities as well as evoked responses to thalamic input. Our theory establishes a general framework for modeling finite-size neural population dynamics based on single cell and synapse parameters and offers an efficient approach to analyzing cortical circuits and computations.

  15. [Geography of effective size of rural populations of Northern Eurasia. Geographic correlation between effective size and level of heterozygosity of populations].

    Science.gov (United States)

    Evsiukov, A N; Zhukova, O V; Sheremet'eva, V A; Shneĭder, Iu V; Rychkov, Iu G

    1996-11-01

    A significant geographical correlation (r = 0.719) was found between the logarithm of effective size (InNe) and heterozygosity level (H) in populations under the assumption of the Hardy-Weinberg equilibrium. The area of highest positive correlation was positioned meridionally between the Ob and Yenisei rivers, from the Arctic coast of Taimyr Peninsula to eastern Sayans and the southern Cis-Baikal region, i.e., in the same region where the highest distribution density of mean Ne values was found. Two additional areas of high correlations were found on the northern Black Sea coast and in the lower Lena river region. Analysis and mapping of correlation ratios eta H/lnNe2 and eta lnNe/H2 revealed that effective size substantially influenced heterozygosity level (as could be expected in the case of an intense gene drift), and heterozygosity level influenced effective size to the same extent. The latter relationship indicated an intense adaptation, and changes in diversity of the gene pool caused substantial demographic changes. However, this might be accounted for by direct gene migration into a population prevailing over reverse migration, i.e., mechanical population growth prevailing over natural growth.

  16. Demographic population model for American shad: will access to additional habitat upstream of dams increase population sizes?

    Science.gov (United States)

    Harris, Julianne E.; Hightower, Joseph E.

    2012-01-01

    American shad Alosa sapidissima are in decline in their native range, and modeling possible management scenarios could help guide their restoration. We developed a density-dependent, deterministic, stage-based matrix model to predict the population-level results of transporting American shad to suitable spawning habitat upstream of dams on the Roanoke River, North Carolina and Virginia. We used data on sonic-tagged adult American shad and oxytetracycline-marked American shad fry both above and below dams on the Roanoke River with information from other systems to estimate a starting population size and vital rates. We modeled the adult female population over 30 years under plausible scenarios of adult transport, effective fecundity (egg production), and survival of adults (i.e., to return to spawn the next year) and juveniles (from spawned egg to age 1). We also evaluated the potential effects of increased survival for adults and juveniles. The adult female population size in the Roanoke River was estimated to be 5,224. With no transport, the model predicted a slow population increase over the next 30 years. Predicted population increases were highest when survival was improved during the first year of life. Transport was predicted to benefit the population only if high rates of effective fecundity and juvenile survival could be achieved. Currently, transported adults and young are less likely to successfully out-migrate than individuals below the dams, and the estimated adult population size is much smaller than either of two assumed values of carrying capacity for the lower river; therefore, transport is not predicted to help restore the stock under present conditions. Research on survival rates, density-dependent processes, and the impacts of structures to increase out-migration success would improve evaluation of the potential benefits of access to additional spawning habitat for American shad.

  17. Simulation of Micron-Sized Debris Populations in Low Earth Orbit

    Science.gov (United States)

    Xu, Y.-L.; Matney, M.; Liou, J.-C.; Hyde, J. L.; Prior, T. G.

    2010-01-01

    The update of ORDEM2000, the NASA Orbital Debris Engineering Model, to its new version . ORDEM2010, is nearly complete. As a part of the ORDEM upgrade, this paper addresses the simulation of micro-debris (greater than 10 micron and smaller than 1 mm in size) populations in low Earth orbit. The principal data used in the modeling of the micron-sized debris populations are in-situ hypervelocity impact records, accumulated in post-flight damage surveys on the space-exposed surfaces of returned spacecrafts. The development of the micro-debris model populations follows the general approach to deriving other ORDEM2010-required input populations for various components and types of debris. This paper describes the key elements and major steps in the statistical inference of the ORDEM2010 micro-debris populations. A crucial step is the construction of a degradation/ejecta source model to provide prior information on the micron-sized objects (such as orbital and object-size distributions). Another critical step is to link model populations with data, which is rather involved. It demands detailed information on area-time/directionality for all the space-exposed elements of a shuttle orbiter and damage laws, which relate impact damage with the physical properties of a projectile and impact conditions such as impact angle and velocity. Also needed are model-predicted debris fluxes as a function of object size and impact velocity from all possible directions. In spite of the very limited quantity of the available shuttle impact data, the population-derivation process is satisfactorily stable. Final modeling results obtained from shuttle window and radiator impact data are reasonably convergent and consistent, especially for the debris populations with object-size thresholds at 10 and 100 micron.

  18. Effects of sample size on estimates of population growth rates calculated with matrix models.

    Directory of Open Access Journals (Sweden)

    Ian J Fiske

    Full Text Available BACKGROUND: Matrix models are widely used to study the dynamics and demography of populations. An important but overlooked issue is how the number of individuals sampled influences estimates of the population growth rate (lambda calculated with matrix models. Even unbiased estimates of vital rates do not ensure unbiased estimates of lambda-Jensen's Inequality implies that even when the estimates of the vital rates are accurate, small sample sizes lead to biased estimates of lambda due to increased sampling variance. We investigated if sampling variability and the distribution of sampling effort among size classes lead to biases in estimates of lambda. METHODOLOGY/PRINCIPAL FINDINGS: Using data from a long-term field study of plant demography, we simulated the effects of sampling variance by drawing vital rates and calculating lambda for increasingly larger populations drawn from a total population of 3842 plants. We then compared these estimates of lambda with those based on the entire population and calculated the resulting bias. Finally, we conducted a review of the literature to determine the sample sizes typically used when parameterizing matrix models used to study plant demography. CONCLUSIONS/SIGNIFICANCE: We found significant bias at small sample sizes when survival was low (survival = 0.5, and that sampling with a more-realistic inverse J-shaped population structure exacerbated this bias. However our simulations also demonstrate that these biases rapidly become negligible with increasing sample sizes or as survival increases. For many of the sample sizes used in demographic studies, matrix models are probably robust to the biases resulting from sampling variance of vital rates. However, this conclusion may depend on the structure of populations or the distribution of sampling effort in ways that are unexplored. We suggest more intensive sampling of populations when individual survival is low and greater sampling of stages with high

  19. Effects of sample size on estimates of population growth rates calculated with matrix models.

    Science.gov (United States)

    Fiske, Ian J; Bruna, Emilio M; Bolker, Benjamin M

    2008-08-28

    Matrix models are widely used to study the dynamics and demography of populations. An important but overlooked issue is how the number of individuals sampled influences estimates of the population growth rate (lambda) calculated with matrix models. Even unbiased estimates of vital rates do not ensure unbiased estimates of lambda-Jensen's Inequality implies that even when the estimates of the vital rates are accurate, small sample sizes lead to biased estimates of lambda due to increased sampling variance. We investigated if sampling variability and the distribution of sampling effort among size classes lead to biases in estimates of lambda. Using data from a long-term field study of plant demography, we simulated the effects of sampling variance by drawing vital rates and calculating lambda for increasingly larger populations drawn from a total population of 3842 plants. We then compared these estimates of lambda with those based on the entire population and calculated the resulting bias. Finally, we conducted a review of the literature to determine the sample sizes typically used when parameterizing matrix models used to study plant demography. We found significant bias at small sample sizes when survival was low (survival = 0.5), and that sampling with a more-realistic inverse J-shaped population structure exacerbated this bias. However our simulations also demonstrate that these biases rapidly become negligible with increasing sample sizes or as survival increases. For many of the sample sizes used in demographic studies, matrix models are probably robust to the biases resulting from sampling variance of vital rates. However, this conclusion may depend on the structure of populations or the distribution of sampling effort in ways that are unexplored. We suggest more intensive sampling of populations when individual survival is low and greater sampling of stages with high elasticities.

  20. Increased Rates of Respiratory and Diarrheal Illnesses in HIV-Negative Persons Living With HIV-Infected Individuals in a Densely Populated Urban Slum in Kenya.

    Science.gov (United States)

    Wong, Joshua M; Cosmas, Leonard; Nyachieo, Dhillon; Williamson, John M; Olack, Beatrice; Okoth, George; Njuguna, Henry; Feikin, Daniel R; Burke, Heather; Montgomery, Joel M; Breiman, Robert F

    2015-09-01

    Prolonged pathogen shedding and increased duration of illness associated with infections in immunosuppressed individuals put close human immunodeficiency virus (HIV)-negative contacts of HIV-infected persons at increased risk of exposure to infectious pathogens. We calculated incidence and longitudinal prevalence (number of days per year) of influenzalike illness (ILI), diarrhea, and nonspecific febrile illness during 2008 from a population-based surveillance program in the urban slum of Kibera (Kenya) that included 1830 HIV-negative household contacts of HIV-infected individuals and 13 677 individuals living in exclusively HIV-negative households. For individuals ≥5 years old, incidence was significantly increased for ILI (risk ratio [RR], 1.47; P 5 years old. Targeted interventions are needed, including ensuring that HIV-infected persons are receiving appropriate care and treatment. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  1. Transgender Population Size in the United States: a Meta-Regression of Population-Based Probability Samples

    Science.gov (United States)

    Sevelius, Jae M.

    2017-01-01

    Background. Transgender individuals have a gender identity that differs from the sex they were assigned at birth. The population size of transgender individuals in the United States is not well-known, in part because official records, including the US Census, do not include data on gender identity. Population surveys today more often collect transgender-inclusive gender-identity data, and secular trends in culture and the media have created a somewhat more favorable environment for transgender people. Objectives. To estimate the current population size of transgender individuals in the United States and evaluate any trend over time. Search methods. In June and July 2016, we searched PubMed, Cumulative Index to Nursing and Allied Health Literature, and Web of Science for national surveys, as well as “gray” literature, through an Internet search. We limited the search to 2006 through 2016. Selection criteria. We selected population-based surveys that used probability sampling and included self-reported transgender-identity data. Data collection and analysis. We used random-effects meta-analysis to pool eligible surveys and used meta-regression to address our hypothesis that the transgender population size estimate would increase over time. We used subsample and leave-one-out analysis to assess for bias. Main results. Our meta-regression model, based on 12 surveys covering 2007 to 2015, explained 62.5% of model heterogeneity, with a significant effect for each unit increase in survey year (F = 17.122; df = 1,10; b = 0.026%; P = .002). Extrapolating these results to 2016 suggested a current US population size of 390 adults per 100 000, or almost 1 million adults nationally. This estimate may be more indicative for younger adults, who represented more than 50% of the respondents in our analysis. Authors’ conclusions. Future national surveys are likely to observe higher numbers of transgender people. The large variety in questions used to ask

  2. The village/commune safety policy and HIV prevention efforts among key affected populations in Cambodia: finding a balance

    Directory of Open Access Journals (Sweden)

    Thomson Nick

    2012-07-01

    Full Text Available Abstract The Village/Commune Safety Policy was launched by the Ministry of Interior of the Kingdom of Cambodia in 2010 and, due to a priority focus on “cleaning the streets”, has created difficulties for HIV prevention programs attempting to implement programs that work with key affected populations including female sex workers and people who inject drugs. The implementation of the policy has forced HIV program implementers, the UN and various government counterparts to explore and develop collaborative ways of delivering HIV prevention services within this difficult environment. The following case study explores some of these efforts and highlights the promising development of a Police Community Partnership Initiative that it is hoped will find a meaningful balance between the Village/Commune Safety Policy and HIV prevention efforts with key affected populations in Cambodia.

  3. Neglected Population, Neglected Right: Children Living with HIV and the Right to Science.

    Science.gov (United States)

    Scanlon, Michael L; MacNaughton, Gillian; Sprague, Courtenay

    2017-12-01

    The laws, language, and tools of human rights have been instrumental in expanding access to lifesaving treatment for people living with HIV. Children, however, remain a neglected population, as evidenced by inadequate child-specific and child-friendly HIV treatment options. In this article, we explore the right to science, a potentially powerful but underdeveloped right in international law, and its application to research and development for pediatric HIV treatment. Drawing on reports of human rights bodies and scholars and applying the human rights typology of state obligations to respect, protect, and fulfill, we argue that states have five core obligations related to research and development for child-specific and child-friendly treatment: (1) adopting a public goods approach to science and science policy; (2) including and protecting children in research activities; (3) adopting legal and policy frameworks to support research and development through public funding and private sector incentives; (4) promoting international cooperation and assistance; and (5) ensuring the participation of marginalized communities in decision-making processes. In concluding, we make a number of recommendations for states, human rights bodies, international organizations, civil society, and private industry to further develop and implement the right to science.

  4. 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.

  5. Embryonic IGF2 expression is not associated with offspring size among populations of a placental fish.

    Directory of Open Access Journals (Sweden)

    Matthew Schrader

    Full Text Available In organisms that provision young between fertilization and birth, mothers and their developing embryos are expected to be in conflict over embryonic growth. In mammalian embryos, the expression of Insulin-like growth factor II (IGF2 plays a key role in maternal-fetal interactions and is thought to be a focus of maternal-fetal conflict. Recent studies have suggested that IGF2 is also a focus of maternal-fetal conflict in placental fish in the family Poeciliidae. However, whether the expression of IGF2 influences offspring size, the trait over which mothers and embryos are likely to be in conflict, has not been assessed in a poeciliid. We tested whether embryonic IGF2 expression varied among four populations of a placental poeciliid that display large and consistent differences in offspring size at birth. We found that IGF2 expression varied significantly among embryonic stages with expression being 50% higher in early stage embryos than late stage embryos. There were no significant differences among populations in IGF2 expression; small differences in expression between population pairs with different offspring sizes were comparable in magnitude to those between population pairs with the same offspring sizes. Our results indicate that variation in IGF2 transcript abundance does not contribute to differences in offspring size among H. formosa populations.

  6. Intraspecific variation in erythrocyte sizes among populations of Hypsiboas cordobas (Anura: Hylidae

    Directory of Open Access Journals (Sweden)

    Mariana Baraquet

    2013-12-01

    Full Text Available We studied the morphology and size of erythrocytes of H. cordobae, and analysed the geographic variation of this character along the distribution of the species, in relation to the latitudinal and altitudinal distances. Erythrocyte shape of the H. cordobae is ellipsoidal and the nuclei are also ellipsoidal and centrally oriented. Erythrocyte and nuclear size showed significant differences among populations, with the highest mean size corresponding to the population of Achiras (low altitude site and the lowest mean size to Los Linderos (high altitude site. There was no significant relationship between the latitude of each population and the both erythrocyte and nuclear size. The altitudinal variation in erythrocyte cell size may be attributable to the surface available for gas exchange; a small erythrocyte offers a possibility of greater rate of exchange than a larger one. Our results are consistent with studies of other amphibians, where intraspecific comparisons of populations at different altitudes show that individuals at higher altitudes are characterized by smaller erythrocytes.

  7. Gaussian process-based Bayesian nonparametric inference of population size trajectories from gene genealogies.

    Science.gov (United States)

    Palacios, Julia A; Minin, Vladimir N

    2013-03-01

    Changes in population size influence genetic diversity of the population and, as a result, leave a signature of these changes in individual genomes in the population. We are interested in the inverse problem of reconstructing past population dynamics from genomic data. We start with a standard framework based on the coalescent, a stochastic process that generates genealogies connecting randomly sampled individuals from the population of interest. These genealogies serve as a glue between the population demographic history and genomic sequences. It turns out that only the times of genealogical lineage coalescences contain information about population size dynamics. Viewing these coalescent times as a point process, estimating population size trajectories is equivalent to estimating a conditional intensity of this point process. Therefore, our inverse problem is similar to estimating an inhomogeneous Poisson process intensity function. We demonstrate how recent advances in Gaussian process-based nonparametric inference for Poisson processes can be extended to Bayesian nonparametric estimation of population size dynamics under the coalescent. We compare our Gaussian process (GP) approach to one of the state-of-the-art Gaussian Markov random field (GMRF) methods for estimating population trajectories. Using simulated data, we demonstrate that our method has better accuracy and precision. Next, we analyze two genealogies reconstructed from real sequences of hepatitis C and human Influenza A viruses. In both cases, we recover more believed aspects of the viral demographic histories than the GMRF approach. We also find that our GP method produces more reasonable uncertainty estimates than the GMRF method. Copyright © 2013, The International Biometric Society.

  8. Population regulation in Magellanic penguins: what determines changes in colony size?

    Directory of Open Access Journals (Sweden)

    Luciana M Pozzi

    Full Text Available Seabirds are often studied at individual colonies, but the confounding effects of emigration and mortality processes in open populations may lead to inappropriate conclusions on the mechanisms underlying population changes. Magellanic penguin (Spheniscus magellanicus colonies of variable population sizes are distributed along the Argentine coastline. In recent decades, several population and distributional changes have occurred, with some colonies declining and others newly established or increasing. We integrated data of eight colonies scattered along ∼600 km in Northern Patagonia (from 41°26´S, 65°01´W to 45°11´S, 66°30´W, Rio Negro and Chubut provinces and conducted analysis in terms of their growth rates, production of young and of the dependence of those vital rates on colony age, size, and location. We contrasted population trends estimated from abundance data with those derived from population modeling to understand if observed growth rates were attainable under closed population scenarios. Population trends were inversely related to colony size, suggesting a density dependent growth pattern. All colonies located in the north--which were established during the last decades--increased at high rates, with the smallest, recently established colonies growing at the fastest rate. In central-southern Chubut, where colonies are the oldest, the largest breeding aggregations declined, but smaller colonies remained relatively stable. Results provided strong evidence that dispersal played a major role in driving local trends. Breeding success was higher in northern colonies, likely mediated by favorable oceanographic conditions. However, mean foraging distance and body condition of chicks at fledging were influenced by colony size. Recruitment of penguins in the northern area may have been triggered by a combination of density dependence, likely exacerbated by less favorable oceanographic conditions in the southern sector. Our results

  9. Effects of insecticide exposure on movement and population size estimates of predatory ground beetles (Coleoptera: Carabidae).

    Science.gov (United States)

    Prasifka, Jarrad R; Lopez, Miriam D; Hellmich, Richard L; Prasifka, Patricia L

    2008-01-01

    Estimates of arthropod population size may paradoxically increase following insecticide applications. Research with ground beetles (Coleoptera: Carabidae) suggests that such unusual results reflect increased arthropod movement and capture in traps rather than real changes in population size. However, it is unclear whether direct (hyperactivity) or indirect (prey-mediated) mechanisms produce increased movement. Video tracking of Scarites quadriceps Chaudior indicated that brief exposure to lambda-cyhalothrin or tefluthrin increased total distance moved, maximum velocity and percentage of time moving. Repeated measurements on individual beetles indicated that movement decreased 240 min after initial lambda-cyhalothrin exposure, but increased again following a second exposure, suggesting hyperactivity could lead to increased trap captures in the field. Two field experiments in which ground beetles were collected after lambda-cyhalothrin or permethrin application attempted to detect increases in population size estimates as a result of hyperactivity. Field trials used mark-release-recapture methods in small plots and natural carabid populations in larger plots, but found no significant short-term (<6 day) increases in beetle trap captures. The disagreement between laboratory and field results suggests mechanisms other than hyperactivity may better explain unusual changes in population size estimates. When traps are used as a primary sampling tool, unexpected population-level effects should be interpreted carefully or with additional data less influenced by arthropod activity.

  10. Effects of host-plant population size and plant sex on a specialist leaf-miner

    Science.gov (United States)

    Bañuelos, María-José; Kollmann, Johannes

    2011-03-01

    Animal population density has been related to resource patch size through various hypotheses such as those derived from island biogeography and resource concentration theory. This theoretical framework can be also applied to plant-herbivore interactions, and it can be modified by the sex of the host-plant, and density-dependent relationships. Leaf-miners are specialised herbivores that leave distinct traces on infested leaves in the form of egg scars, mines, signs of predation and emergence holes. This allows the life cycle of the insect to be reconstructed and the success at the different stages to be estimated. The main stages of the leaf-miner Phytomyza ilicis were recorded in eleven populations of the evergreen host Ilex aquifolium in Denmark. Survival rates were calculated and related to population size, sex of the host plant, and egg and mine densities. Host population size was negatively related to leaf-miner prevalence, with larger egg and mine densities in small populations. Percentage of eggs hatching and developing into mines, and percentage of adult flies emerging from mines also differed among host populations, but were not related to population size or host cover. Feeding punctures left by adults were marginally more frequent on male plants, whereas egg scars and mines were more common on females. Overall survival rate from egg stage to adult emergence was higher on female plants. Egg density was negatively correlated with hatching, while mine density was positively correlated with emergence of the larvae. The inverse effects of host population size were not in line with predictions based on island biogeography and resource concentration theory. We discuss how a thorough knowledge of the immigration behaviour of this fly might help to understand the patterns found.

  11. High cancer-related mortality in an urban, predominantly African-American, HIV-infected population.

    Science.gov (United States)

    Riedel, David J; Mwangi, Evelyn Ivy W; Fantry, Lori E; Alexander, Carla; Hossain, Mian B; Pauza, C David; Redfield, Robert R; Gilliam, Bruce L

    2013-04-24

    To determine mortality associated with a new cancer diagnosis in an urban, predominantly African-American, HIV-infected population. Retrospective cohort study. All HIV-infected patients diagnosed with cancer between 1 January 2000 and 30 June 2010 were reviewed. Mortality was examined using Kaplan-Meier estimates and Cox proportional hazards models. There were 470 cases of cancer among 447 patients. Patients were predominantly African-American (85%) and male (79%). Non-AIDS-defining cancers (NADCs, 69%) were more common than AIDS-defining cancers (ADCs, 31%). Cumulative cancer incidence increased significantly over the study period. The majority (55.9%) was taking antiretroviral therapy (ART) at cancer diagnosis or started afterward (26.9%); 17.2% never received ART. Stage 3 or 4 cancer was diagnosed in 67%. There were 226 deaths during 1096 person years of follow-up, yielding an overall mortality rate of 206 per 1000 person years. The cumulative mortality rate at 30 days, 1 year, and 2 years was 6.5, 32.2, and 41.4%, respectively. Mortality was similar between patients on ART whether they started before or after the cancer diagnosis but was higher in patients who never received ART. In patients with a known cause of death, 68% were related to progression of the underlying cancer. In a large cohort of urban, predominantly African-American patients with HIV and cancer, many patients presented with late-stage cancer. There was substantial 30-day and 2-year mortality, although ART had a significant mortality benefit. Deaths were most often caused by progression of cancer and not from another HIV-related or AIDS-related event.

  12. Dynamics of adrenal steroids are related to variations in Th1 and Treg populations during Mycobacterium tuberculosis infection in HIV positive persons.

    Directory of Open Access Journals (Sweden)

    Maria Florencia Quiroga

    Full Text Available Tuberculosis (TB remains the most frequent cause of illness and death from an infectious agent, and its interaction with HIV has devastating effects. We determined plasma levels of dehydroepiandrosterone (DHEA, its circulating form DHEA-suphate (DHEA-s and cortisol in different stages of M. tuberculosis infection, and explored their role on the Th1 and Treg populations during different scenarios of HIV-TB coinfection, including the immune reconstitution inflammatory syndrome (IRIS, a condition related to antiretroviral treatment. DHEA levels were diminished in HIV-TB and HIV-TB IRIS patients compared to healthy donors (HD, HIV+ individuals and HIV+ individuals with latent TB (HIV-LTB, whereas dehydroepiandrosterone sulfate (DHEA-s levels were markedly diminished in HIV-TB IRIS individuals. HIV-TB and IRIS patients presented a cortisol/DHEA ratio significantly higher than HIV+, HIV-LTB and HD individuals. A positive correlation was observed between DHEA-s and CD4 count among HIV-TB individuals. Conversely, cortisol plasma level inversely correlated with CD4 count within HIV-TB individuals. M. tuberculosis-specific Th1 lymphocyte count was increased after culturing PBMC from HIV-TB individuals in presence of DHEA. We observed an inverse correlation between DHEA-s plasma level and Treg frequency in co-infected individuals, and CD4+FoxP3+ Treg frequency was increased in HIV-TB and IRIS patients compared to other groups. Strikingly, we observed a prominent CD4+CD25-FoxP3+ population across HIV-TB and HIV-TB IRIS patients, which frequency correlated with DHEA plasma level. Finally, DHEA treatment negatively regulated FoxP3 expression without altering Treg frequency in co-infected patients. These data suggest an enhancing role for DHEA in the immune response against M. tuberculosis during HIV-TB coinfection and IRIS.

  13. Thymic size in uninfected infants born to HIV-positive mothers and fed with pasteurized human milk

    DEFF Research Database (Denmark)

    Jeppesen, Dorthe Lisbeth; Hasselbalch, H; Ersbøll, A K

    2003-01-01

    AIM: To examine the size of the thymus in uninfected infants born to HIV-positive mothers and to study the effects of feeding by human donor milk on the size of the thymus in these infants. METHODS: The absolute and relative thymic size was assessed by sonography as thymic index (Ti), and the Ti....../weight-ratio (Ti/w) at birth and at 4 mo of age in 12 healthy uninfected infants born to HlV-infected mothers. All infants were exclusively fed pasteurized donor milk. The results were compared with those obtained from a previous cohort of exclusively breastfed, partially breastfed and exclusively formula......-fed infants. RESULTS: At birth the Ti was reduced in infants born to HIV-infected mothers in comparison with that in control infants but this difference disappeared when their birthweights were taken into consideration (Ti/w-ratio). At 4 mo of age the geometric mean Ti of infants fed donor milk was 23...

  14. Perceptions of body size and its association with HIV/AIDS | Matoti ...

    African Journals Online (AJOL)

    After the quantitative analysis was completed, focus group discussions explored perceptions about body image and the relation to HIV among purposely selected participants. Data were summarised by content based on questions discussed. Results: Sixty-nine per cent of the participants associated a thin figure with a ...

  15. Association of attitudes and beliefs towards antiretroviral therapy with HIV-seroprevalence in the general population of Kisumu, Kenya.

    Directory of Open Access Journals (Sweden)

    Craig R Cohen

    Full Text Available Since antiretroviral therapy (ART became available in the developed world, the prevalence of unprotected sex and the incidence of sexually transmitted infections (STIs and HIV have increased. We hypothesized that a similar phenomenon may be occurring in sub-Saharan Africa concomitant with the scale-up of HIV treatment.We conducted a general population-based survey in Kisumu, Kenya. Participants completed an interview that included demographics as well as ART-related attitudes and beliefs (AB and then underwent HIV serological testing. Exploratory and confirmatory factor analyses of AB about ART indicated two factors: 1 ART-related risk compensation (increased sexual risk taking now that ART is available; and 2 a perception that HIV is more controllable now that ART is available. Logistic regression was used to determine associations of these factors with HIV-seroprevalence after controlling for age.1,655 (90% of 1,844 people aged 15-49 contacted, including 749 men and 906 women, consented to participate in the study. Most participants (n = 1164; 71% had heard of ART. Of those who had heard of ART, 23% believed ART was a cure for HIV. ART-related risk compensation (Adjusted (AOR = 1.45, 95% CI 1.16-1.81, and a belief that ART cures HIV (AOR = 2.14, 95% CI 1.22-3.76 were associated with an increased HIV seroprevalence in men but not women after controlling for age. In particular, ART-related risk compensation was associated with an increased HIV-seroprevalence in young (aged 15-24 years men (OR = 1.56; 95% CI 1.12-2.19.ART-related risk compensation and a belief that ART cures HIV were associated with an increased HIV seroprevalence among men but not women. HIV prevention programs in sub-Saharan Africa that target the general population should include educational messages about ART and address the changing beliefs about HIV in the era of greater ART availability.

  16. Population size estimation in Yellowstone wolves with error-prone noninvasive microsatellite genotypes.

    Science.gov (United States)

    Creel, Scott; Spong, Goran; Sands, Jennifer L; Rotella, Jay; Zeigle, Janet; Joe, Lawrence; Murphy, Kerry M; Smith, Douglas

    2003-07-01

    Determining population sizes can be difficult, but is essential for conservation. By counting distinct microsatellite genotypes, DNA from noninvasive samples (hair, faeces) allows estimation of population size. Problems arise because genotypes from noninvasive samples are error-prone, but genotyping errors can be reduced by multiple polymerase chain reaction (PCR). For faecal genotypes from wolves in Yellowstone National Park, error rates varied substantially among samples, often above the 'worst-case threshold' suggested by simulation. Consequently, a substantial proportion of multilocus genotypes held one or more errors, despite multiple PCR. These genotyping errors created several genotypes per individual and caused overestimation (up to 5.5-fold) of population size. We propose a 'matching approach' to eliminate this overestimation bias.

  17. Genetic algorithm with small population size for search feasible control parameters for parallel hybrid electric vehicles

    Directory of Open Access Journals (Sweden)

    Yu-Huei Cheng

    2017-11-01

    Full Text Available The control strategy is a major unit in hybrid electric vehicles (HEVs. In order to provide suitable control parameters for reducing fuel consumptions and engine emissions while maintaining vehicle performance requirements, the genetic algorithm (GA with small population size is applied to search for feasible control parameters in parallel HEVs. The electric assist control strategy (EACS is used as the fundamental control strategy of parallel HEVs. The dynamic performance requirements stipulated in the Partnership for a New Generation of Vehicles (PNGV is considered to maintain the vehicle performance. The known ADvanced VehIcle SimulatOR (ADVISOR is used to simulate a specific parallel HEV with urban dynamometer driving schedule (UDDS. Five population sets with size 5, 10, 15, 20, and 25 are used in the GA. The experimental results show that the GA with population size of 25 is the best for selecting feasible control parameters in parallel HEVs.

  18. Attrition and Opportunities Along the HIV Care Continuum: Findings From a Population-Based Sample, North West Province, South Africa.

    Science.gov (United States)

    Lippman, Sheri A; Shade, Starley B; El Ayadi, Alison M; Gilvydis, Jennifer M; Grignon, Jessica S; Liegler, Teri; Morris, Jessica; Naidoo, Evasen; Prach, Lisa M; Puren, Adrian; Barnhart, Scott

    2016-09-01

    Attrition along the HIV care continuum slows gains in mitigating the South African HIV epidemic. Understanding population-level gaps in HIV identification, linkage, retention in care, and viral suppression is critical to target programming. We conducted a population-based household survey, HIV rapid testing, point-of-care CD4 testing, and viral load measurement from dried blood spots using multistage cluster sampling in 2 subdistricts of North West Province from January to March, 2014. We used weighting and multiple imputation of missing data to estimate HIV prevalence, undiagnosed infection, linkage and retention in care, medication adherence, and viral suppression. We sampled 1044 respondents aged 18-49. HIV prevalence was 20.0% (95% confidence interval: 13.7 to 26.2) for men and 26.7% (95% confidence interval: 22.1 to 31.4) for women. Among those HIV positive, 48.4% of men and 75.7% of women were aware of their serostatus; 44.0% of men and 74.8% of women reported ever linking to HIV care; 33.1% of men and 58.4% of women were retained in care; and 21.6% of men and 50.0% of women had dried blood spots viral loads <5000 copies per milliliter. Among those already linked to care, 81.7% on antiretroviral treatment (ART) and 56.0% of those not on ART were retained in care, and 51.8% currently retained in care on ART had viral loads <5000 copies per milliliter. Despite expanded treatment in South Africa, attrition along the continuum of HIV care is slowing prevention progress. Improved detection is critically needed, particularly among men. Reported linkage and retention is reasonable for those on ART; however, failure to achieve viral suppression is worrisome.

  19. 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

  20. Frequency of HIV type 2 infections among blood donor population from India: A 10-year experience

    Directory of Open Access Journals (Sweden)

    Kannangai R

    2010-01-01

    Full Text Available Purpose: In India, HIV-2 epidemic is alongside with HIV-1. Blood banks are introducing nucleic acid testing (NAT for screening. The limitation of NAT systems is the inability to detect HIV-2. Materials and Method : An analysis of HIV screening of a blood bank at a tertiary care center from 1998 to 2007 was carried out. Results : A total of 175026 donors were screened by serological assays and 789 were reactive for HIV antibody. Only 478 (61% were confirmed positive by Western blot/immunoblot. There were 465 (97.2% donations positive for HIV-1, 6 (1.3% for HIV-2 (monotypic infection and 7 (1.5% for HIV-1 and HIV-2 (dual infection. Conclusion : We show the presence of HIV-2 infection among the blood donors and the need for incorporating HIV-2 detection also in the NAT systems.

  1. Varied sensitivity to therapy of HIV-1 strains in CD4+ lymphocyte sub-populations upon ART initiation

    Directory of Open Access Journals (Sweden)

    Paxton William A

    2010-12-01

    Full Text Available Abstract Background Although antiretroviral therapy (ART has proven its success against HIV-1, the long lifespan of infected cells and viral latency prevent eradication. In this study we analyzed the sensitivity to ART of HIV-1 strains in naïve, central memory and effector memory CD4+ lymphocyte subsets. Methods From five patients cellular HIV-1 infection levels were quantified before and after initiation of therapy (2-5 weeks. Through sequencing the C2V3 region of the HIV-1 gp120 envelope, we studied the effect of short-term therapy on virus variants derived from naïve, central memory and effector memory CD4+ lymphocyte subsets. Results During short-term ART, HIV-1 infection levels declined in all lymphocyte subsets but not as much as RNA levels in serum. Virus diversity in the naïve and central memory lymphocyte populations remained unchanged, whilst diversity decreased in serum and the effector memory lymphocytes. ART differentially affected the virus populations co-circulating in one individual harboring a dual HIV-1 infection. Changes in V3 charge were found in all individuals after ART initiation with increases within the effector memory subset and decreases found in the naïve cell population. Conclusions During early ART virus diversity is affected mainly in the serum and effector memory cell compartments. Differential alterations in V3 charge were observed between effector memory and naïve populations. While certain cell populations can be targeted preferentially during early ART, some virus strains demonstrate varied sensitivity to therapy, as shown from studying two strains within a dual HIV-1 infected individual.

  2. Estimating population size of a nocturnal burrow-nesting seabird using acoustic monitoring and habitat mapping

    Directory of Open Access Journals (Sweden)

    Steffen Oppel

    2014-04-01

    Full Text Available Population size assessments for nocturnal burrow-nesting seabirds are logistically challenging because these species are active in colonies only during darkness and often nest on remote islands where manual inspections of breeding burrows are not feasible. Many seabird species are highly vocal, and recent technological innovations now make it possible to record and quantify vocal activity in seabird colonies. Here we test the hypothesis that remotely recorded vocal activity in Cory’s shearwater (Calonectris borealis breeding colonies in the North Atlantic increases with nest density, and combined this relationship with cliff habitat mapping to estimate the population size of Cory’s shearwaters on the island of Corvo (Azores. We deployed acoustic recording devices in 9 Cory’s shearwater colonies of known size to establish a relationship between vocal activity and local nest density (slope = 1.07, R2 = 0.86, p < 0.001. We used this relationship to predict the nest density in various cliff habitat types and produced a habitat map of breeding cliffs to extrapolate nest density around the island of Corvo. The mean predicted nest density on Corvo ranged from 6.6 (2.1–16.2 to 27.8 (19.5–36.4 nests/ha. Extrapolation of habitat-specific nest densities across the cliff area of Corvo resulted in an estimate of 6326 Cory’s shearwater nests (95% confidence interval: 3735–10,524. This population size estimate is similar to previous assessments, but is too imprecise to detect moderate changes in population size over time. While estimating absolute population size from acoustic recordings may not be sufficiently precise, the strong positive relationship that we found between local nest density and recorded calling rate indicates that passive acoustic monitoring may be useful to document relative changes in seabird populations over time.

  3. HBV/HIV co-infection and APOBEC3G polymorphisms in a population from Burkina Faso.

    Science.gov (United States)

    Compaore, Tegwinde Rebeca; Diarra, Birama; Assih, Maleki; Obiri-Yeboah, Dorcas; Soubeiga, Serge Theophile; Ouattara, Abdoul Karim; Tchelougou, Damehan; Bisseye, Cyrille; Bakouan, Didier Romuald; Compaore, Issaka Pierre; Dembele, Augustine; Djigma, Wendkuuni Florencia; Simpore, Jacques

    2016-07-22

    Apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3G (APOBEC3G) is a potent host defense factor, which interferes with HIV-1 and HBV. Our study had three objectives, to screen a population of HIV-1 infected and uninfected patients in Burkina Faso for HBV, to screen the population for APOBEC3G variants rs6001417, rs8177832, and rs35228531 previously described, and to analyze the effect of these three variants and their haplotypes on HIV-1/HBV co-infection in Burkina Faso. HBV detection was performed on samples from HIV-1 infected and uninfected subjects using rapid detection tests and real-time PCR. APOBEC3 genotyping was done by the TaqMan allelic discrimination method. Fisher Exact test, Odds ratio (OR), confidence intervals (CI) at 95 %, Linkage disequilibrium (LD) summary statistics and haplotype frequencies were calculated. The prevalence of HBV was 56.7 % among HIV-1 positive patients of our study while it was about 12.8 % among HIV-1 seronegative subjects. Genotype E was the genotype of HBV present in our hepatitis B positive samples. Minor allele frequencies of rs6001417, rs8177832, and rs35228531 were higher in seronegative subjects. The T minor allele of variant rs35228531 was protective against HIV-1/HBV co-infection with OR = 0.61, 95 % CI (0.42-0.90), p = 0.013. There was also an association between the GGT haplotype and protection against HIV-1/HBV co-infection, OR = 0.57, 95 % CI (0.33-0.99), p = 0.050. The other haplotypes present in the population were not statistically significant. There minor allele T of the rs35228531 was protective against HIV mono-infection OR = 0.53, 95 % CI (0.3-0.93), P = 0.030. But there was no effect of protection against HBV mono-infection. APOBEC3G through its variants rs6001417, rs8177832, and rs35228531, in this study interferes with HIV-1/HBV co-infection could be due the HIV-1 mono-infection in a population from Burkina Faso.

  4. A macroevolutionary explanation for energy equivalence in the scaling of body size and population density.

    Science.gov (United States)

    Damuth, John

    2007-05-01

    Across a wide array of animal species, mean population densities decline with species body mass such that the rate of energy use of local populations is approximately independent of body size. This "energetic equivalence" is particularly evident when ecological population densities are plotted across several or more orders of magnitude in body mass and is supported by a considerable body of evidence. Nevertheless, interpretation of the data has remained controversial, largely because of the difficulty of explaining the origin and maintenance of such a size-abundance relationship in terms of purely ecological processes. Here I describe results of a simulation model suggesting that an extremely simple mechanism operating over evolutionary time can explain the major features of the empirical data. The model specifies only the size scaling of metabolism and a process where randomly chosen species evolve to take resource energy from other species. This process of energy exchange among particular species is distinct from a random walk of species abundances and creates a situation in which species populations using relatively low amounts of energy at any body size have an elevated extinction risk. Selective extinction of such species rapidly drives size-abundance allometry in faunas toward approximate energetic equivalence and maintains it there.

  5. The niche construction of cultural complexity: interactions between innovations, population size and the environment.

    Science.gov (United States)

    Fogarty, Laurel; Creanza, Nicole

    2017-12-05

    Niche construction is a process through which organisms alter their environments and, in doing so, influence or change the selective pressures to which they are subject. 'Cultural niche construction' refers specifically to the effect of cultural traits on the selective environments of other biological or cultural traits and may be especially important in human evolution. In addition, the relationship between population size and cultural accumulation has been the subject of extensive debate, in part because anthropological studies have demonstrated a significant association between population size and toolkit complexity in only a subset of studied cultures. Here, we review the role of cultural innovation in constructing human evolutionary niches and introduce a new model to describe the accumulation of human cultural traits that incorporates the effects of cultural niche construction. We consider the results of this model in light of available data on human toolkit sizes across populations to help elucidate the important differences between food-gathering societies and food-producing societies, in which niche construction may be a more potent force. These results support the idea that a population's relationship with its environment, represented here by cultural niche construction, should be considered alongside population size in studies of cultural complexity.This article is part of the themed issue 'Process and pattern in innovations from cells to societies'. © 2017 The Author(s).

  6. Reference serving sizes for the Brazilian population: An analysis of processed food labels

    Directory of Open Access Journals (Sweden)

    Nathalie Kliemann

    2014-06-01

    Full Text Available OBJECTIVE: To compare serving sizes reported on processed food labels with reference serving sizes according to nutrition labeling legislation and the "Food Guide for the Brazilian Population". METHODS: This cross-sectional study analyzed the labels of 2,072 processed foods in a supermarket of Florianópolis, Santa Caratina, Brazil. The foods were classified according to the Brazilian food labeling legislation. Central tendency and variability values were calculated for the serving sizes and energy values reported on the labels, as well as the ratio between the reported and reference energy value. The Spearman correlation test was performed between the reference serving size and the reference energy density, and also between the reference serving size and energy density of each study food. RESULTS: Nutrition labeling and the Food Guide presented reference servings with different sizes and energy values. The serving sizes reported on the labels did not follow either of the references and presented heterogeneous values, with a maximum range of 55-240 g among ready and semi-ready pre-prepared dishes. The reported energy values were between 0.1 times smaller and 2.4 times larger than the reference values. The reference serving sizes presented a highly inverse correlation with the reference energy density (Spearman coefficient= 0.9 and a very low inverse correlation with the energy density of the foods analyzed (Spearman coefficient= 0.2. CONCLUSION: This study showed the need for standardizing reference serving size information for the Brazilian population as well as reviewing nutrition labeling legislation in order to standardize the serving sizes reported on labels and to update the reference energy density used to calculate serving sizes.

  7. Effectiveness and efficiency of improving HIV service provision for key populations in Nicaragua

    Directory of Open Access Journals (Sweden)

    Edward Ivor Broughton

    2016-11-01

    Full Text Available ObjectiveHIV in Nicaragua is concentrated among key populations (KPs – men who have sex with men, female sex workers and female transgender – in whom prevalence is 600-4 000 times higher than the general population. The USAID PrevenSida Project is aimed at increasing healthy behavior among KPs and people with HIV and improving testing, counseling, and continuity of prevention and treatment by building capacity and improving performance of non-governmental organizations (NGOs providing services to KPs. We evaluated the cost-effectiveness of PrevenSida’s activities. MethodsThis retrospective observational evaluation used individuals in KPs covered by NGOs receiving assistance from PrevenSida from 2012 to 2014. Cost-effectiveness analysis compared PrevenSida’s intervention with business-as-usual. Model inputs were generated from epidemiological modeling and PrevenSida’s records.ResultsBy 2014, 24 NGOs received grants and technical assistance from PrevenSida with 72 955 people in KPs served at $11.32/person ($9.39 to $16.55/person depending on region. The estimated incremental cost-effectiveness ratio was $50 700/HIV case averted or $2 600/Disability-adjusted Life Year (DALY averted (95% CI: $1 000-$99 000 and $50-$5 100, respectively.ConclusionPrevenSida distributed about $600 000 in grants and used $230 000 to support 24 NGOs in 2014. Cost-effectiveness from the program perspective compared to no program was slightly over half of GDP per capita per DALY averted, considered highly cost-effective by WHO criteria. Cost and efficiency varied by region, reflecting the number of people in KPs receiving services. Cost-sharing by NGOs improved cost-effectiveness from the program perspective and likely promotes sustainability. Focused interventions for KP service provision organizations can be acceptably efficient in this setting.

  8. Genetic variability and effective population size when local extinction and recolonization of subpopulations are frequent

    Science.gov (United States)

    Maruyama, Takeo; Kimura, Motoo

    1980-01-01

    If a population (species) consists of n haploid lines (subpopulations) which reproduce asexually and each of which is subject to random extinction and subsequent replacement, it is shown that, at equilibrium in which mutational production of new alleles and their random extinction balance each other, the genetic diversity (1 minus the sum of squares of allelic frequencies) is given by 2Nev/(1 + 2Nev), where [Formula: see text] in which Ñ is the harmonic mean of the population size per line, n is the number of lines (assumed to be large), λ is the rate of line extinction, and v is the mutation rate (assuming the infinite neutral allele model). In a diploid population (species) consisting of n colonies, if migration takes place between colonies at the rate m (the island model) in addition to extinction and recolonization of colonies, it is shown that effective population size is [Formula: see text] If the rate of colony extinction (λ) is much larger than the migration rate of individuals, the effective population size is greatly reduced compared with the case in which no colony extinctions occur (in which case Ne = nÑ). The stepping-stone type of recolonization scheme is also considered. Bearing of these results on the interpretation of the level of genetic variability at the enzyme level observed in natural populations is discussed from the standpoint of the neutral mutation-random drift hypothesis. PMID:16592920

  9. Opportunities for Enhanced Strategic Use of Surveys, Medical Records, and Program Data for HIV Surveillance of Key Populations: Scoping Review

    Science.gov (United States)

    Baral, Stefan D; Edwards, Jessie K; Zadrozny, Sabrina; Hargreaves, James; Zhao, Jinkou; Sabin, Keith

    2018-01-01

    Background Normative guidelines from the World Health Organization recommend tracking strategic information indicators among key populations. Monitoring progress in the global response to the HIV epidemic uses indicators put forward by the Joint United Nations Programme on HIV/AIDS. These include the 90-90-90 targets that require a realignment of surveillance data, routinely collected program data, and medical record data, which historically have developed separately. Objective The aim of this study was to describe current challenges for monitoring HIV-related strategic information indicators among key populations ((men who have sex with men [MSM], people in prisons and other closed settings, people who inject drugs, sex workers, and transgender people) and identify future opportunities to enhance the use of surveillance data, programmatic data, and medical record data to describe the HIV epidemic among key populations and measure the coverage of HIV prevention, care, and treatment programs. Methods To provide a historical perspective, we completed a scoping review of the expansion of HIV surveillance among key populations over the past three decades. To describe current efforts, we conducted a review of the literature to identify published examples of SI indicator estimates among key populations. To describe anticipated challenges and future opportunities to improve measurement of strategic information indicators, particularly from routine program and health data, we consulted participants of the Third Global HIV Surveillance Meeting in Bangkok, where the 2015 World Health Organization strategic information guidelines were launched. Results There remains suboptimal alignment of surveillance and programmatic data, as well as routinely collected medical records to facilitate the reporting of the 90-90-90 indicators for HIV among key populations. Studies (n=3) with estimates of all three 90-90-90 indicators rely on cross-sectional survey data. Programmatic data and

  10. Increasing HIV-1 Drug Resistance Between 2010 and 2012 in Adults Participating in Population-Based HIV Surveillance in Rural KwaZulu-Natal, South Africa.

    Science.gov (United States)

    Manasa, Justen; Danaviah, Siva; Lessells, Richard; Elshareef, Muna; Tanser, Frank; Wilkinson, Eduan; Pillay, Sureshnee; Mthiyane, Hloniphile; Mwambi, Henry; Pillay, Deenan; de Oliveira, Tulio

    2016-08-01

    As more human immunodeficiency virus (HIV)-infected patients access combination antiretroviral therapy (cART), higher proportions of newly infected patients may be infected with drug-resistant viruses. Regular surveillance of transmitted drug resistance (TDR) is required in southern Africa where high rates of transmission persist despite rapid expansion of ART. Dried blood spot samples from cART-naive participants from two rounds of an annual population-based HIV surveillance program in rural KwaZulu-Natal were tested for HIV RNA, and samples with HIV RNA >10,000 copies/ml were genotyped for drug resistance. The 2009 surveillance of drug resistance mutation (SDRM) list was used for drug resistance interpretation. The data were added to previously published data from the same program, and the χ(2) test for trend was used to test for trend in estimated prevalence of any TDR. Seven hundred and one participants' data were analyzed: 67 (2010), 381 (2011), and 253 (2012). No TDR was detected in 2010. Years 2011 and 2012 had 18 participants with SDRMs 4.7% and 7.1%, respectively (p = .02, χ(2) test for trend). The nonnucleoside reverse transcriptase inhibitor mutation, K103N, was the most common mutation, occurring in 27 (3.8%) of the participants, while nucleoside reverse transcriptase inhibitor (NRTI) SDRMs were detected in 10 (1.4%) of the participants, of whom eight had only a single NRTI SDRM. The increase in levels of drug resistance observed in this population could be a signal of increasing transmission of drug-resistant HIV. Thus, continued surveillance is critical to inform public health policies around HIV treatment and prevention.

  11. Prevalence and risk factors for osteopenia/osteoporosis in an HIV-infected male population.

    Science.gov (United States)

    Tomazic, Janez; Ul, Katja; Volcansek, Gabriele; Gorensek, Samo; Pfeifer, Misa; Karner, Primoz; Prezelj, Janez; Vidmar, Gaj; Vidmar, Ludvik

    2007-01-01

    The objective of our investigation was to estimate the prevalence of osteopenia/osteoporosis in men with HIV/AIDS and evaluate the role of antiretroviral treatment (ART), HIV and other risk factors in reducing bone mineral density (BMD). All known Slovenian HIV-infected ART-naïve and treated males (infected or treated > 12 months) were invited to participate in a cross-sectional study. Data were collected on age, BMI, waist-hip ratio, family history of hip fracture, duration of infection, duration of ART, smoking, alcohol, exercise, viral load and CD4+ cells. BMD was measured using dual X-ray absorptiometry. A total of 96 patients (out of 133 who fulfilled the inclusion criteria) were assessed and allocated into three groups: group A (n = 24), ART-naïve; group B1 (n = 37), treated with non-protease-inhibitor (PI) containing ART; and group B2 (n = 35), treated with PI-containing ART. The prevalence of osteopenia/osteoporosis was 57/96 (59%): osteopenia 45/96 (47%) and osteoporosis 12/96 (12%). Significantly lower BMD was detected in group A (P = 0.020). Multiple logistic regression analysis showed ART to be an independent negative predictor for reduced BMD (P = 0.037; OR = 0.29, 95%CI 0.09-0.93). Vitamin D(3) deficiency was detected in 79 (82%) of the patients. The study group represented 72% of the national HIV-infected male population; this proportion being higher than in any other study reported to date. The prevalence of reduced BMD was notably higher than the national prevalence among men of comparable age. There was no association between reduced BMD and any specific ART. According to our results, absence of ART was confirmed as an independent predictor of osteopenia/osteoporosis. Targeted screening and early treatment present a reasonable strategy for preventing reduced BMD in HIV-infected patients, but correcting vitamin D(3) levels could also be an important component.

  12. Clutch size in populations and species of cnemidophorines (Squamata: Teiidae on the eastern coast of Brazil

    Directory of Open Access Journals (Sweden)

    VANDERLAINE A. MENEZES

    2014-06-01

    Full Text Available We analyzed some reproductive aspects of 16 coastal populations, belonging to five lizard species (A. ocellifera, A. abaetensis, A. nativo, A. littoralis and C. lacertoides from different restinga habitats along the eastern coast of Brazil. This study aimed to evaluate to what extent the reproductive aspects vary geographically and among species. For each female, we recorded the number of vitellogenic follicles, size and color of the largest follicle, presence and size of corpora lutea, and number and size of oviductal eggs. Clutch size of almost all coastal populations/species of Ameivula had little variation and most clutches were composed of two eggs. There was a significant relationship between female size and the mean clutch size when females from different species were pooled. Mean egg volume, among species, varied from 420 to 655 mm3. Relative clutch mass varied from 0.129 to 0.159 and did not differ significantly among species. We concluded that the five coastal species studied (four bisexuals and one parthenogenetic had similar reproductive characteristics. Most of them presented multiple clutches, low clutch size and low relative clutch mass, similar to other species in the genus and to unisexual and bisexual species of the Teiidae family.

  13. METER-SIZED MOONLET POPULATION IN SATURN'S C RING AND CASSINI DIVISION

    International Nuclear Information System (INIS)

    Baillié, Kévin; Colwell, Joshua E.; Esposito, Larry W.; Lewis, Mark C.

    2013-01-01

    Stellar occultations observed by the Cassini Ultraviolet Imaging Spectrograph reveal the presence of transparent holes a few meters to a few tens of meters in radial extent in otherwise optically thick regions of the C ring and the Cassini Division. We attribute the holes to gravitational disturbances generated by a population of ∼10 m boulders in the rings that is intermediate in size between the background ring particle size distribution and the previously observed ∼100 m propeller moonlets in the A ring. The size distribution of these boulders is described by a shallower power-law than the one that describes the ring particle size distribution. The number and size distribution of these boulders could be explained by limited accretion processes deep within Saturn's Roche zone.

  14. Revealing life-history traits by contrasting genetic estimations with predictions of effective population size.

    Science.gov (United States)

    Greenbaum, Gili; Renan, Sharon; Templeton, Alan R; Bouskila, Amos; Saltz, David; Rubenstein, Daniel I; Bar-David, Shirli

    2017-12-22

    Effective population size, a central concept in conservation biology, is now routinely estimated from genetic surveys and can also be theoretically predicted from demographic, life-history, and mating-system data. By evaluating the consistency of theoretical predictions with empirically estimated effective size, insights can be gained regarding life-history characteristics and the relative impact of different life-history traits on genetic drift. These insights can be used to design and inform management strategies aimed at increasing effective population size. We demonstrated this approach by addressing the conservation of a reintroduced population of Asiatic wild ass (Equus hemionus). We estimated the variance effective size (N ev ) from genetic data (N ev =24.3) and formulated predictions for the impacts on N ev of demography, polygyny, female variance in lifetime reproductive success (RS), and heritability of female RS. By contrasting the genetic estimation with theoretical predictions, we found that polygyny was the strongest factor affecting genetic drift because only when accounting for polygyny were predictions consistent with the genetically measured N ev . The comparison of effective-size estimation and predictions indicated that 10.6% of the males mated per generation when heritability of female RS was unaccounted for (polygyny responsible for 81% decrease in N ev ) and 19.5% mated when female RS was accounted for (polygyny responsible for 67% decrease in N ev ). Heritability of female RS also affected N ev ; hf2=0.91 (heritability responsible for 41% decrease in N ev ). The low effective size is of concern, and we suggest that management actions focus on factors identified as strongly affecting Nev, namely, increasing the availability of artificial water sources to increase number of dominant males contributing to the gene pool. This approach, evaluating life-history hypotheses in light of their impact on effective population size, and contrasting

  15. Reevaluation of immune activation in the era of cART and an aging HIV-infected population.

    Science.gov (United States)

    de Armas, Lesley R; Pallikkuth, Suresh; George, Varghese; Rinaldi, Stefano; Pahwa, Rajendra; Arheart, Kristopher L; Pahwa, Savita

    2017-10-19

    Biological aging is associated with immune activation (IA) and declining immunity due to systemic inflammation. It is widely accepted that HIV infection causes persistent IA and premature immune senescence despite effective antiretroviral therapy and virologic suppression; however, the effects of combined HIV infection and aging are not well defined. Here, we assessed the relationship between markers of IA and inflammation during biological aging in HIV-infected and -uninfected populations. Antibody response to seasonal influenza vaccination was implemented as a measure of immune competence and relationships between IA, inflammation, and antibody responses were explored using statistical modeling appropriate for integrating high-dimensional data sets. Our results show that markers of IA, such as coexpression of HLA antigen D related (HLA-DR) and CD38 on CD4+ T cells, exhibit strong associations with HIV infection but not with biological age. Certain variables that showed a strong relationship with aging, such as declining naive and CD38+ CD4 and CD8+ T cells, did so regardless of HIV infection. Interestingly, the variable of biological age was not identified in a predictive model as significantly impacting vaccine responses in either group, while distinct IA and inflammatory variables were closely associated with vaccine response in HIV-infected and -uninfected populations. These findings shed light on the most relevant and persistent immune defects during virological suppression with antiretroviral therapy.

  16. Anti HIV-2 serological screening in Portuguese populations native from or having had close contact with Africa.

    Science.gov (United States)

    Saal, F; Sidibe, S; Alves-Cardoso, E; Terrinha, A; Gessain, A; Poirot, Y; Montagnier, L; Peries, J

    1987-01-01

    To gather epidemiologic information on the spread of human immunodeficiency virus (HIV)-2 in Portugal, sera were collected in 1985 from 156 healthy adults currently living in Portugal but natives of Guinea Bissau, Cape Verde Islands, Saint Tome/Prince, Angola, and Mozambique and from 321 native Portuguese men and women who had close contact with local African populations. As a control, sera were collected from 102 health Portuguese with no previous contact with Africa or African natives. The enzyme-linked immunosorbent assay (ELISA) developed by Diagnostic Pasteur was used to screen for antibodies to HIV. No positive reactions were recorded in the control population. In contracts, 9 (6%) of the African natives and 7 (2%) of the contacts of Africans were HIV-positive, 6 of the positive sera were from women and 10 were from men. Significantly, 1 of the HIV-2-positive serum samples was from a native of Mozambique and 3 were from natives of Angola. This suggests that HIV-2 infection may have spread to other former Portuguese colonies, and foreign army soldiers who were at 1 time residents of Mozambique or Angola should be considered a risk group capable of spreading HIV-2 infection to other countries.

  17. Asian elephants in China: estimating population size and evaluating habitat suitability.

    Directory of Open Access Journals (Sweden)

    Li Zhang

    Full Text Available We monitored the last remaining Asian elephant populations in China over the past decade. Using DNA tools and repeat genotyping, we estimated the population sizes from 654 dung samples collected from various areas. Combined with morphological individual identifications from over 6,300 elephant photographs taken in the wild, we estimated that the total Asian elephant population size in China is between 221 and 245. Population genetic structure and diversity were examined using a 556-bp fragment of mitochondrial DNA, and 24 unique haplotypes were detected from DNA analysis of 178 individuals. A phylogenetic analysis revealed two highly divergent clades of Asian elephants, α and β, present in Chinese populations. Four populations (Mengla, Shangyong, Mengyang, and Pu'Er carried mtDNA from the α clade, and only one population (Nangunhe carried mtDNA belonging to the β clade. Moreover, high genetic divergence was observed between the Nangunhe population and the other four populations; however, genetic diversity among the five populations was low, possibly due to limited gene flow because of habitat fragmentation. The expansion of rubber plantations, crop cultivation, and villages along rivers and roads had caused extensive degradation of natural forest in these areas. This had resulted in the loss and fragmentation of elephant habitats and had formed artificial barriers that inhibited elephant migration. Using Geographic Information System, Global Positioning System, and Remote Sensing technology, we found that the area occupied by rubber plantations, tea farms, and urban settlements had dramatically increased over the past 40 years, resulting in the loss and fragmentation of elephant habitats and forming artificial barriers that inhibit elephant migration. The restoration of ecological corridors to facilitate gene exchange among isolated elephant populations and the establishment of cross-boundary protected areas between China and Laos to secure

  18. An Artificial Immune System with Feedback Mechanisms for Effective Handling of Population Size

    Science.gov (United States)

    Gao, Shangce; Wang, Rong-Long; Ishii, Masahiro; Tang, Zheng

    This paper represents a feedback artificial immune system (FAIS). Inspired by the feedback mechanisms in the biological immune system, the proposed algorithm effectively manipulates the population size by increasing and decreasing B cells according to the diversity of the current population. Two kinds of assessments are used to evaluate the diversity aiming to capture the characteristics of the problem on hand. Furthermore, the processing of adding and declining the number of population is designed. The validity of the proposed algorithm is tested for several traveling salesman benchmark problems. Simulation results demonstrate the efficiency of the proposed algorithm when compared with the traditional genetic algorithm and an improved clonal selection algorithm.

  19. Characterization of HIV-Specific CD4+T Cell Responses against Peptides Selected with Broad Population and Pathogen Coverage

    DEFF Research Database (Denmark)

    Buggert, Marcus; Norstrom, Melissa M.; Czarnecki, Chris

    2012-01-01

    for the identification of HIV-specific CD4+ T cells targeting broadly reactive epitopes in populations with diverse ethnic background stems from the vast genomic variation of HIV and the diversity of the host cellular immune system. Here, we describe a novel epitope selection strategy, PopCover, that aims to resolve...... this challenge, and identify a set of potential HLA class II-restricted HIV epitopes that in concert will provide optimal viral and host coverage. Using this selection strategy, we identified 64 putative epitopes (peptides) located in the Gag, Nef, Env, Pol and Tat protein regions of HIV. In total, 73...... II-restricted epitopes. All together, selection strategies, such as PopCover, might with success be used for the evaluation of antigen-specific CD4+ T cell responses and design of future vaccines....

  20. The Vicious Cycle of Stigma and Disclosure in "Self-Management": A Study Among the Dutch HIV Population.

    Science.gov (United States)

    de Vries, Daniel H; Koppen, Luca; Lopez, Adolfo Mejia; Foppen, Reina

    2016-12-01

    Though HIV has become a chronic disease, HIV-related stigma has remained. This article reports on a study that asked how Dutch people living with HIV-AIDS (PLWHA) experienced stigmatization and devised self-management strategies. We used qualitative findings from a survey questionnaire conducted among 468 Dutch HIV-positive people (3% of the population), using a stratified research sample. Findings show how respondents experience relatively high public (30%), self- (26%) and structural (15%) stigma. At the same time, results show the importance of selective disclosure as a self-management strategy. About half the respondents disclose selectively, while 16% does not disclose at all. We conclude that many Dutch PLHWA remain caught up in a vicious cycle of stigma and nondisclosure. To break the cycle, respondents point at the importance of stigma reduction campaigns using actual PLWHA. We highlight the importance of workplace programs and training of medical professionals.

  1. Missed Opportunities: barriers to HIV testing during pregnancy from a population based cohort study in rural Uganda.

    Directory of Open Access Journals (Sweden)

    Elin C Larsson

    Full Text Available The aim was to assess population-level HIV-testing uptake among pregnant women, key for access to prevention-of mother to child transmission (PMTCT services, and to identify risk factors for not being HIV tested,The study was conducted May 2008-May 2010 in the Iganga/Mayuge Health and Demographic Surveillance Site (HDSS, Eastern Uganda, during regular surveillance of 68,000 individuals. All women identified to be pregnant May-July 2008 (n=881 were interviewed about pregnancy-related issues and linked to the HDSS database for socio-demographic data. Women were followed-up via antenatal care (ANC register reviews at the health facilities to collect data related to ANC services received, including HIV testing. Adjusted relative risk (aRR, and 95% confidence intervals (CI for not being HIV tested were calculated using multivariable binomial regression among the 544 women who remained after record review.Despite high ANC attendance (96%, the coverage of HIV testing was 64%. Only 6% of pregnant women who sought ANC at a facility without HIV testing services were referred for testing and only 20% received counseling regarding HIV. At ANC facilities with HIV testing services, 85% were tested. Only 4% of the women tested had been couple tested for HIV. Living more than three kilometers away from a health facility with HIV testing services was associated with not being tested both among the poorest (aRR,CI; 1.44,1.02-2.04 and the least poor women (aRR,CI;1.72,1.12-2.63.The lack of on site HIV testing services and distant ANC facilities lead to missed opportunities for PMTCT, especially for the poorest women. Referral systems for HIV testing need to be improved and testing should be expanded to lower level health facilities. This is in order to ensure that the policy of HIV testing during pregnancy is implemented more effectively and that testing is accessible for all.

  2. Estimating demographic contributions to effective population size in an age-structured wild population experiencing environmental and demographic stochasticity.

    Science.gov (United States)

    Trask, Amanda E; Bignal, Eric M; McCracken, Davy I; Piertney, Stuart B; Reid, Jane M

    2017-09-01

    A population's effective size (N e ) is a key parameter that shapes rates of inbreeding and loss of genetic diversity, thereby influencing evolutionary processes and population viability. However, estimating N e , and identifying key demographic mechanisms that underlie the N e to census population size (N) ratio, remains challenging, especially for small populations with overlapping generations and substantial environmental and demographic stochasticity and hence dynamic age-structure. A sophisticated demographic method of estimating N e /N, which uses Fisher's reproductive value to account for dynamic age-structure, has been formulated. However, this method requires detailed individual- and population-level data on sex- and age-specific reproduction and survival, and has rarely been implemented. Here, we use the reproductive value method and detailed demographic data to estimate N e /N for a small and apparently isolated red-billed chough (Pyrrhocorax pyrrhocorax) population of high conservation concern. We additionally calculated two single-sample molecular genetic estimates of N e to corroborate the demographic estimate and examine evidence for unobserved immigration and gene flow. The demographic estimate of N e /N was 0.21, reflecting a high total demographic variance (σ2dg) of 0.71. Females and males made similar overall contributions to σ2dg. However, contributions varied among sex-age classes, with greater contributions from 3 year-old females than males, but greater contributions from ≥5 year-old males than females. The demographic estimate of N e was ~30, suggesting that rates of increase of inbreeding and loss of genetic variation per generation will be relatively high. Molecular genetic estimates of N e computed from linkage disequilibrium and approximate Bayesian computation were approximately 50 and 30, respectively, providing no evidence of substantial unobserved immigration which could bias demographic estimates of N e . Our analyses identify

  3. Cannibalism in a size-structured population: energy extraction and control

    NARCIS (Netherlands)

    Persson, L.; Claessen, D.; de Roos, A.M.; Byström, P.; Sjögren, S.; Svanbäck, R.; Wahlström, E.; Westman, E.

    2004-01-01

    Recent size-structured cannibalistic models point to the importance of the energy gain by cannibals and also show that this gain may result in the emergence of giant individuals. We use a combination of a 10-year field study of a perch (Perca fluviatilis) population and quantitative within-season

  4. Cannibalism in a size-structured population: Enery extraction and control

    NARCIS (Netherlands)

    Persson, L.; Claessen, D.; de Roos, A.M.; Bystrom, P.; Sjogren, S.; Svanback, R.; Wahlstrom, E.; Westman, E.

    2004-01-01

    Recent size-structured cannibalistic models point to the importance of the energy gain by cannibals and also show that this gain may result in the emergence of giant individuals. We use a combination of a 10-year field study of a perch (Perca fluviatilis) population and quantitative within-season

  5. Effects of founder population size on the performance of Orius laevigatus (Hemiptera: Anthocoridae) colonies

    NARCIS (Netherlands)

    Castañe, C.; Bueno, V.H.P.; Carvalho, L.M.; Lenteren, van J.C.

    2014-01-01

    Orius laevigatus (Hemiptera: Anthocoridae) is a key predator of thrips and is mass reared in large numbers for use in biological control. The aim of this study was to evaluate the effect of founder population size on the biological and behavioral performance of O. laevigatus over time. Laboratory

  6. Association Between Educational Level and Risk of Cancer in HIV-infected Individuals and the Background Population: Population-based Cohort Study 1995-2011.

    Science.gov (United States)

    Legarth, Rebecca; Omland, Lars H; Dalton, Susanne O; Kronborg, Gitte; Larsen, Carsten S; Pedersen, Court; Pedersen, Gitte; Gerstoft, Jan; Obel, Niels

    2015-11-15

    Human immunodeficiency virus (HIV)-infected individuals have increased risk of cancer. To our knowledge, no previous study has examined the impact of socioeconomic position on risk and prognosis of cancer in HIV infection. Population-based cohort-study, including HIV-infected individuals diagnosed (without intravenous drug abuse or hepatitis C infection) (n = 3205), and a background population cohort matched by age, gender, and country of birth (n = 22 435) were analyzed. Educational level (low or high) and cancer events were identified in Danish national registers. Cumulative incidences, incidence rate ratios (IRRs), and survival using Kaplan-Meier methods were estimated. Low educational level was associated with increased risk of cancer among HIV-infected individuals compared to population controls: all (adjusted-IRRs: 1.4 [95% confidence interval {CI}, 1.1-1.7] vs 1.1 [95% CI, .9-1.2]), tobacco- and alcohol-related (2.1 [95% CI, 1.3-3.4] vs 1.3 [95% CI, 1.1-1.6]), and other (1.7 [95% CI, 1.1-2.8] vs 0.9 [95% CI, .7-1.0]). Educational level was not associated with infection-related or ill-defined cancers. One-year-survival was not associated with educational level, but HIV-infected individuals with low educational level had lower 5-year-survival following infection-related and ill-defined cancers. Education is associated with risk and prognosis of some cancers in HIV infection, and diverges from what is observed in the background population. © The Author 2015. 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.

  7. Urban Optimum Population Size and Development Pattern Based on Ecological Footprint Model: Case of Zhoushan, China

    Directory of Open Access Journals (Sweden)

    Yuan LU

    2016-09-01

    Full Text Available The agglomeration of population in the city can reflect the prosperity in the economy, society and culture. However, it has also brought a series of problems like environmental pollution, traffic congestion, housing shortage and jobs crisis. The results can be shown as the failure of urban comprehensive function, the decline of city benefits, and the contradiction between socioeconomic circumstance and ecosystem. Therefore, a reasonable population capacity, which is influenced by ecological resources, urban environment, geographical elements, social and economic factors, etc., is objectively needed. How to deal with the relationship between the utilization of natural capital and development of the city is extremely essential. This paper takes Zhoushan Island as an example, which is the fourth largest island off the coast of China. Firstly, the interactively influencing factors of urban optimal population are illustrated. And method is chosen to study the optimal population size. Secondly, based on the model of ecological footprint (EP, the paper calculates and analyzes the ecological footprint and ecological capacity of the Zhoushan Island, in order to explore the optimal population size of the city. Thirdly, analysis and evaluation of the resources and urban environment carrying capacity is made. Finally, the solution of the existing population problems and the suggestion for the future development pattern of the city are proposed in the urban eco-planning of Zhoushan Island. The main strategies can be summarized in two aspects: one is to reduce the ecological footprint, the other is to increase the ecological supply. The conclusion is that the current population of Zhoushan Island is far beyond the optimum population size calculated by the ecological footprint model. Therefore, sustainable development should be the guidance for urban planning in Zhoushan Island, and a low-carbon development pattern for the city is advocated.

  8. Effects of host-plant population size and plant sex on a specialist leaf-miner

    DEFF Research Database (Denmark)

    Bañuelos, María-José; Kollmann, Johannes Christian

    2011-01-01

    of the host-plant, and density-dependent relationships. Leaf-miners are specialised herbivores that leave distinct traces on infested leaves in the form of egg scars, mines, signs of predation and emergence holes. This allows the life cycle of the insect to be reconstructed and the success at the different...... punctures left by adults were marginally more frequent on male plants, whereas egg scars and mines were more common on females. Overall survival rate from egg stage to adult emergence was higher on female plants. Egg density was negatively correlated with hatching, while mine density was positively...... stages to be estimated. The main stages of the leaf-miner Phytomyza ilicis were recorded in eleven populations of the evergreen host Ilex aquifolium in Denmark. Survival rates were calculated and related to population size, sex of the host plant, and egg and mine densities. Host population size...

  9. Measuring coverage in MNCH: population HIV-free survival among children under two years of age in four African countries.

    Directory of Open Access Journals (Sweden)

    Jeffrey S A Stringer

    Full Text Available Population-based evaluations of programs for prevention of mother-to-child HIV transmission (PMTCT are scarce. We measured PMTCT service coverage, regimen use, and HIV-free survival among children ≤24 mo of age in Cameroon, Côte D'Ivoire, South Africa, and Zambia.We randomly sampled households in 26 communities and offered participation if a child had been born to a woman living there during the prior 24 mo. We tested consenting mothers with rapid HIV antibody tests and tested the children of seropositive mothers with HIV DNA PCR or rapid antibody tests. Our primary outcome was 24-mo HIV-free survival, estimated with survival analysis. In an individual-level analysis, we evaluated the effectiveness of various PMTCT regimens. In a community-level analysis, we evaluated the relationship between HIV-free survival and community PMTCT coverage (the proportion of HIV-exposed infants in each community that received any PMTCT intervention during gestation or breastfeeding. We also compared our community coverage results to those of a contemporaneous study conducted in the facilities serving each sampled community. Of 7,985 surveyed children under 2 y of age, 1,014 (12.7% were HIV-exposed. Of these, 110 (10.9% were HIV-infected, 851 (83.9% were HIV-uninfected, and 53 (5.2% were dead. HIV-free survival at 24 mo of age among all HIV-exposed children was 79.7% (95% CI: 76.4, 82.6 overall, with the following country-level estimates: Cameroon (72.6%; 95% CI: 62.3, 80.5, South Africa (77.7%; 95% CI: 72.5, 82.1, Zambia (83.1%; 95% CI: 78.4, 86.8, and Côte D'Ivoire (84.4%; 95% CI: 70.0, 92.2. In adjusted analyses, the risk of death or HIV infection was non-significantly lower in children whose mothers received a more complex regimen of either two or three antiretroviral drugs compared to those receiving no prophylaxis (adjusted hazard ratio: 0.60; 95% CI: 0.34, 1.06. Risk of death was not different for children whose mothers received a more complex regimen

  10. An epidemiological modelling study to estimate the composition of HIV-positive populations including migrants from endemic settings.

    Science.gov (United States)

    Nakagawa, Fumiyo

    2017-01-28

    Migrants account for a significant number of people living with HIV in Europe, and it is important to fully consider this population in national estimates. Using a novel approach with the UK as an example, we present key public health measures of the HIV epidemic, taking into account both in-country infections and infections likely to have been acquired abroad. Mathematical model calibrated to extensive data sources. An individual-based stochastic simulation model is used to calibrate to routinely collected surveillance data in the UK. Data on number of new HIV diagnoses, number of deaths, CD4 cell count at diagnosis, as well as time of arrival into the UK for migrants and the annual number of people receiving care were used. An estimated 106 400 (90% plausibility range: 88 700-124 600) people were living with HIV in the UK in 2013. Twenty-three percent of these people, 24 600 (15 000-36 200) were estimated to be undiagnosed; this number has remained stable over the last decade. An estimated 32% of the total undiagnosed population had CD4 cell count less than 350 cells/μl in 2013. Twenty-five and 23% of black African men and women heterosexuals living with HIV were undiagnosed respectively. We have shown a working example to characterize the HIV population in a European context which incorporates migrants from countries with generalized epidemics. Despite all aspects of HIV care being free and widely available to anyone in need in the UK, there is still a substantial number of people who are not yet diagnosed and thus not in care.

  11. Behavioral and psychosocial interventions for HIV prevention in floating populations in China over the past decade: A systematic literature review and meta-analysis

    NARCIS (Netherlands)

    X. Liu (Xiaona); V. Erasmus (Vicky); Q. Wu (Qing); J.H. Richardus (Jan Hendrik)

    2014-01-01

    textabstractBackground: Floating populations have been repeatedly characterized as "the tipping point" for the HIV epidemic in China. This study aims to systematically summarize and assess the effectiveness of HIV prevention interventions in floating populations in China over the past decade.

  12. Mutation of HIV-1 genomes in a clinical population treated with the mutagenic nucleoside KP1461.

    Science.gov (United States)

    Mullins, James I; Heath, Laura; Hughes, James P; Kicha, Jessica; Styrchak, Sheila; Wong, Kim G; Rao, Ushnal; Hansen, Alexis; Harris, Kevin S; Laurent, Jean-Pierre; Li, Deyu; Simpson, Jeffrey H; Essigmann, John M; Loeb, Lawrence A; Parkins, Jeffrey

    2011-01-14

    The deoxycytidine analog KP1212, and its prodrug KP1461, are prototypes of a new class of antiretroviral drugs designed to increase viral mutation rates, with the goal of eventually causing the collapse of the viral population. Here we present an extensive analysis of viral sequences from HIV-1 infected volunteers from the first "mechanism validation" phase II clinical trial of a mutagenic base analog in which individuals previously treated with antiviral drugs received 1600 mg of KP1461 twice per day for 124 days. Plasma viral loads were not reduced, and overall levels of viral mutation were not increased during this short-term study, however, the mutation spectrum of HIV was altered. A large number (N = 105 per sample) of sequences were analyzed, each derived from individual HIV-1 RNA templates, after 0, 56 and 124 days of therapy from 10 treated and 10 untreated control individuals (>7.1 million base pairs of unique viral templates were sequenced). We found that private mutations, those not found in more than one viral sequence and likely to have occurred in the most recent rounds of replication, increased in treated individuals relative to controls after 56 (p = 0.038) and 124 (p = 0.002) days of drug treatment. The spectrum of mutations observed in the treated group showed an excess of A to G and G to A mutations (p = 0.01), and to a lesser extent T to C and C to T mutations (p = 0.09), as predicted by the mechanism of action of the drug. These results validate the proposed mechanism of action in humans and should spur development of this novel antiretroviral approach.

  13. Mutation of HIV-1 genomes in a clinical population treated with the mutagenic nucleoside KP1461.

    Directory of Open Access Journals (Sweden)

    James I Mullins

    2011-01-01

    Full Text Available The deoxycytidine analog KP1212, and its prodrug KP1461, are prototypes of a new class of antiretroviral drugs designed to increase viral mutation rates, with the goal of eventually causing the collapse of the viral population. Here we present an extensive analysis of viral sequences from HIV-1 infected volunteers from the first "mechanism validation" phase II clinical trial of a mutagenic base analog in which individuals previously treated with antiviral drugs received 1600 mg of KP1461 twice per day for 124 days. Plasma viral loads were not reduced, and overall levels of viral mutation were not increased during this short-term study, however, the mutation spectrum of HIV was altered. A large number (N = 105 per sample of sequences were analyzed, each derived from individual HIV-1 RNA templates, after 0, 56 and 124 days of therapy from 10 treated and 10 untreated control individuals (>7.1 million base pairs of unique viral templates were sequenced. We found that private mutations, those not found in more than one viral sequence and likely to have occurred in the most recent rounds of replication, increased in treated individuals relative to controls after 56 (p = 0.038 and 124 (p = 0.002 days of drug treatment. The spectrum of mutations observed in the treated group showed an excess of A to G and G to A mutations (p = 0.01, and to a lesser extent T to C and C to T mutations (p = 0.09, as predicted by the mechanism of action of the drug. These results validate the proposed mechanism of action in humans and should spur development of this novel antiretroviral approach.

  14. Use of the superpopulation approach to estimate breeding population size: An example in asynchronously breeding birds

    Science.gov (United States)

    Williams, K.A.; Frederick, P.C.; Nichols, J.D.

    2011-01-01

    Many populations of animals are fluid in both space and time, making estimation of numbers difficult. Much attention has been devoted to estimation of bias in detection of animals that are present at the time of survey. However, an equally important problem is estimation of population size when all animals are not present on all survey occasions. Here, we showcase use of the superpopulation approach to capture-recapture modeling for estimating populations where group membership is asynchronous, and where considerable overlap in group membership among sampling occasions may occur. We estimate total population size of long-legged wading bird (Great Egret and White Ibis) breeding colonies from aerial observations of individually identifiable nests at various times in the nesting season. Initiation and termination of nests were analogous to entry and departure from a population. Estimates using the superpopulation approach were 47-382% larger than peak aerial counts of the same colonies. Our results indicate that the use of the superpopulation approach to model nesting asynchrony provides a considerably less biased and more efficient estimate of nesting activity than traditional methods. We suggest that this approach may also be used to derive population estimates in a variety of situations where group membership is fluid. ?? 2011 by the Ecological Society of America.

  15. Population structure and effective/census population size ratio in threatened three-spined stickleback populations from an isolated river basin in northwest Spain.

    Science.gov (United States)

    Pérez-Figueroa, A; Fernández, C; Amaro, R; Hermida, M; San Miguel, E

    2015-08-01

    Variability at 20 microsatellite loci was examined to assess the population genetic structure, gene flow, and effective population size (N(e)) in three populations of three-spined stickleback (Gasterosteus aculeatus) from the upper basin of the Miño River in Galicia, NW Spain, where this species is threatened. The three populations showed similar levels of genetic diversity. There is a significant genetic differentiation between the three populations, but also significant gene flow. N(e) estimates based on linkage disequilibrium yielded values of 355 for the Miño River population and 241 and 311 for the Rato and Guisande Rivers, respectively, although we expect that these are overestimates. N(e) estimates based on temporal methods, considering gene flow or not, for the tributaries yielded values of 30-56 and 47-56 for the Rato and Guisande Rivers, respectively. Estimated census size (N(c)) for the Rato River was 880 individuals. This yielded a N(e)/N(c) estimate of 3-6 % for temporal estimation of N(e), which is within the empirical range observed in freshwater fishes. We suggest that the three populations analyzed have a sufficient level of genetic diversity with some genetic structure. Additionally, the absence of physical barriers suggests that conservation efforts and monitoring should focus in the whole basin as a unit.

  16. Social-cultural factors of HIV-related stigma among the Chinese general population in Hong Kong.

    Science.gov (United States)

    Yeo, Tien Ee Dominic; Chu, Tsz Hang

    2017-10-01

    HIV-related stigma in the wider community compounds the suffering of people living with HIV (PLWH) and hampers effective HIV prevention and care. This study examines the level of public stigma toward PLWH in Hong Kong and associated social-cultural factors. A telephone survey was conducted in June-July 2016 with 1080 Chinese adults aged 18-94 randomly selected from the general population. The results indicate substantial degree of public stigma toward PLWH. Overall, 58.1% of the participants endorsed at least one statement indicating negative social judgment of PLWH. Over 40% attributed HIV infections to irresponsible behaviors and nearly 30% perceived most PLWH as promiscuous. About 20% considered HIV to be a punishment for bad behavior and believed that PLWH should feel ashamed of themselves. These statistics indicate that HIV-related stigma among the general Hong Kong population had no noticeable reduction in a decade but is lower than that among rural and urban populations in China. Our findings suggest that the lower stigma in Hong Kong may be linked to higher education levels rather than Hongkongers' more Westernized outlook. The results of a multiple regression analysis showed that education level (β = -.19), homophobia (β = .30), and conformity to norms (β = .14) were independent predictors of HIV-related stigma but not age, income, or cultural orientations. By differentiating between associated social-cultural factors, this study provides a more nuanced understanding of the layered nature of HIV-related stigma: not broadly grounded in religion or Chinese culture but stemming from more specific social-cultural beliefs - perceptions of norm violation and negative attitudes toward homosexuality, which were not mutually exclusive. These findings have implications for HIV-related stigma reduction by providing evidence for the importance of addressing homophobia. Existing HIV publicity activities should be re-examined for inadvertent contribution

  17. Population Size and Decadal Trends of Three Penguin Species Nesting at Signy Island, South Orkney Islands.

    Directory of Open Access Journals (Sweden)

    Michael J Dunn

    Full Text Available We report long-term changes in population size of three species of sympatrically breeding pygoscelid penguins: Adélie (Pygoscelis adeliae, chinstrap (Pygoscelis antarctica and gentoo (Pygoscelis papua ellsworthii over a 38 year period at Signy Island, South Orkney Islands, based on annual counts from selected colonies and decadal all-island systematic counts of occupied nests. Comparing total numbers of breeding pairs over the whole island from 1978/79 to 2015/16 revealed varying fortunes: gentoo penguin pairs increased by 255%, (3.5% per annum, chinstrap penguins declined by 68% (-3.6% per annum and Adélie penguins declined by 42% (-1.5% per annum. The chinstrap population has declined steadily over the last four decades. In contrast, Adélie and gentoo penguins have experienced phases of population increase and decline. Annual surveys of selected chinstrap and Adélie colonies produced similar trends from those revealed by island-wide surveys, allowing total island population trends to be inferred relatively well. However, while the annual colony counts of chinstrap and Adélie penguins showed a trend consistent in direction with the results from all-island surveys, the magnitude of estimated population change was markedly different between colony wide and all island counts. Annual population patterns suggest that pair numbers in the study areas partly reflect immigration and emigration of nesting birds between different parts of the island. Breeding success for all three species remained broadly stable over time in the annually monitored colonies. Breeding success rates in gentoo and chinstrap penguins were strongly correlated, despite the differing trends in population size. This study shows the importance of effective, standardised monitoring to accurately determine long-term population trajectories. Our results indicate significant declines in the Adélie and chinstrap penguin populations at Signy Island over the last five decades, and a

  18. Population Size and Decadal Trends of Three Penguin Species Nesting at Signy Island, South Orkney Islands.

    Science.gov (United States)

    Dunn, Michael J; Jackson, Jennifer A; Adlard, Stacey; Lynnes, Amanda S; Briggs, Dirk R; Fox, Derren; Waluda, Claire M

    2016-01-01

    We report long-term changes in population size of three species of sympatrically breeding pygoscelid penguins: Adélie (Pygoscelis adeliae), chinstrap (Pygoscelis antarctica) and gentoo (Pygoscelis papua ellsworthii) over a 38 year period at Signy Island, South Orkney Islands, based on annual counts from selected colonies and decadal all-island systematic counts of occupied nests. Comparing total numbers of breeding pairs over the whole island from 1978/79 to 2015/16 revealed varying fortunes: gentoo penguin pairs increased by 255%, (3.5% per annum), chinstrap penguins declined by 68% (-3.6% per annum) and Adélie penguins declined by 42% (-1.5% per annum). The chinstrap population has declined steadily over the last four decades. In contrast, Adélie and gentoo penguins have experienced phases of population increase and decline. Annual surveys of selected chinstrap and Adélie colonies produced similar trends from those revealed by island-wide surveys, allowing total island population trends to be inferred relatively well. However, while the annual colony counts of chinstrap and Adélie penguins showed a trend consistent in direction with the results from all-island surveys, the magnitude of estimated population change was markedly different between colony wide and all island counts. Annual population patterns suggest that pair numbers in the study areas partly reflect immigration and emigration of nesting birds between different parts of the island. Breeding success for all three species remained broadly stable over time in the annually monitored colonies. Breeding success rates in gentoo and chinstrap penguins were strongly correlated, despite the differing trends in population size. This study shows the importance of effective, standardised monitoring to accurately determine long-term population trajectories. Our results indicate significant declines in the Adélie and chinstrap penguin populations at Signy Island over the last five decades, and a gradual

  19. Routine HIV testing in Botswana: a population-based study on attitudes, practices, and human rights concerns.

    Directory of Open Access Journals (Sweden)

    Sheri D Weiser

    2006-07-01

    Full Text Available The Botswana government recently implemented a policy of routine or "opt-out" HIV testing in response to the high prevalence of HIV infection, estimated at 37% of adults.We conducted a cross-sectional, population-based study of 1,268 adults from five districts in Botswana to assess knowledge of and attitudes toward routine testing, correlates of HIV testing, and barriers and facilitators to testing, 11 months after the introduction of this policy. Most participants (81% reported being extremely or very much in favor of routine testing. The majority believed that this policy would decrease barriers to testing (89%, HIV-related stigma (60%, and violence toward women (55%, and would increase access to antiretroviral treatment (93%. At the same time, 43% of participants believed that routine testing would lead people to avoid going to the doctor for fear of testing, and 14% believed that this policy could increase gender-based violence related to testing. The prevalence of self-reported HIV testing was 48%. Adjusted correlates of testing included female gender (AOR = 1.5, 95% CI = 1.1-1.9, higher education (AOR = 2.0, 95% CI = 1.5-2.7, more frequent healthcare visits (AOR = 1.9, 95% CI = 1.3-2.7, perceived access to HIV testing (AOR = 1.6, 95% CI = 1.1-2.5, and inconsistent condom use (AOR = 1.6, 95% CI = 1.2-2.1. Individuals with stigmatizing attitudes toward people living with HIV and AIDS were less likely to have been tested for HIV/AIDS (AOR = 0.7, 95% CI = 0.5-0.9 or to have heard of routine testing (AOR = 0.59, 95% CI = 0.45-0.76. While experiences with voluntary and routine testing overall were positive, 68% felt that they could not refuse the HIV test. Key barriers to testing included fear of learning one's status (49%, lack of perceived HIV risk (43%, and fear of having to change sexual practices with a positive HIV test (33%.Routine testing appears to be widely supported and may reduce barriers to testing in Botswana. As routine testing is

  20. HIV Risk Behaviors in the U.S. Transgender Population: Prevalence and Predictors in a Large Internet Sample

    Science.gov (United States)

    Feldman, Jamie; Romine, Rebecca Swinburne; Bockting, Walter O.

    2014-01-01

    To study the influence of gender on HIV risk, a sample of the U.S. transgender population (N = 1,229) was recruited via the Internet. HIV risk and prevalence were lower than reported in prior studies of localized, urban samples, but higher than the overall U.S. population. Findings suggest that gender nonconformity alone does not itself result in markedly higher HIV risk. Sex with nontransgender men emerged as the strongest independent predictor of unsafe sex for both male-to-female (MtF) and female-to-male (FtM) participants. These sexual relationships constitute a process that may either affirm or problematize gender identity and sexual orientation, with different emphases for MtFs and FtMs, respectively. PMID:25022491

  1. Predator-driven brain size evolution in natural populations of Trinidadian killifish (Rivulus hartii)

    Science.gov (United States)

    Walsh, Matthew R.; Broyles, Whitnee; Beston, Shannon M.; Munch, Stephan B.

    2016-01-01

    Vertebrates exhibit extensive variation in relative brain size. It has long been assumed that this variation is the product of ecologically driven natural selection. Yet, despite more than 100 years of research, the ecological conditions that select for changes in brain size are unclear. Recent laboratory selection experiments showed that selection for larger brains is associated with increased survival in risky environments. Such results lead to the prediction that increased predation should favour increased brain size. Work on natural populations, however, foreshadows the opposite trajectory of evolution; increased predation favours increased boldness, slower learning, and may thereby select for a smaller brain. We tested the influence of predator-induced mortality on brain size evolution by quantifying brain size variation in a Trinidadian killifish, Rivulus hartii, from communities that differ in predation intensity. We observed strong genetic differences in male (but not female) brain size between fish communities; second generation laboratory-reared males from sites with predators exhibited smaller brains than Rivulus from sites in which they are the only fish present. Such trends oppose the results of recent laboratory selection experiments and are not explained by trade-offs with other components of fitness. Our results suggest that increased male brain size is favoured in less risky environments because of the fitness benefits associated with faster rates of learning and problem-solving behaviour. PMID:27412278

  2. Sexual behaviour and HIV/sexually transmitted infection risk behaviours in the general population of Slovenia, a low HIV prevalence country in central Europe

    Science.gov (United States)

    Klavs, I; Rodrigues, L C; Wellings, K; Weiss, H A; Hayes, R

    2009-01-01

    Objectives: To describe sexual and HIV/sexually transmitted infection (STI) risk behaviours in Slovenia. Methods: A nationally representative cross-sectional survey of the general population aged 18–49 years in 1999–2001 was conducted. The data were collected by face-to-face interviews and anonymous self-administered questionnaires. Statistical methods for complex survey data were used. Results: 849 men and 903 women were interviewed. In the past 5 years, both men and women reported a median of one heterosexual partner (means 3.2, 1.5, respectively), concurrent heterosexual partnerships were reported by 24.4% of men and 8.2% of women, heterosexual sex with non-Slovenian partners by 12.6% of men and 12.2% of women, forced sex by 4.8% of women, paid heterosexual sex by 2.6% of men, sex with another man by 0.6% of men and heterosexual sex with an injecting drug user by 1.2% of men and 1.3% of women. In the past year, 22.7% of men and 9.5% of women reported forming at least one new heterosexual partnership. The mean numbers of episodes of heterosexual sex in the previous 4 weeks were 6.1 for men and 6.0 for women. Consistent and inconsistent condom use was reported more frequently among men reporting multiple female partners and those not married or cohabiting. Conclusions: Recent patterns of reported sexual behaviour are consistent with a low risk of HIV and STI transmission in Slovenia. The results will inform Slovenian sexual health policies including HIV/STI prevention, and are particularly valuable because population-based data on HIV/STI risk behaviour have not previously been available in low HIV prevalence countries of central Europe. PMID:19060036

  3. Fetal size monitoring and birth-weight prediction: a new population-based approach.

    Science.gov (United States)

    Gjessing, H K; Grøttum, P; Økland, I; Eik-Nes, S H

    2017-04-01

    To develop a complete, population-based system for ultrasound-based fetal size monitoring and birth-weight prediction for use in the second and third trimesters of pregnancy. Using 31 516 ultrasound examinations from a population-based Norwegian clinical database, we constructed fetal size charts for biparietal diameter, femur length and abdominal circumference from 24 to 42 weeks' gestation. A reference curve of median birth weight for gestational age was estimated using 45 037 birth weights. We determined how individual deviations from the expected ultrasound measures predicted individual percentage deviations from expected birth weight. The predictive quality was assessed by explained variance of birth weight and receiver-operating characteristics curves for prediction of small-for-gestational age. A curve for intrauterine estimated fetal weight was constructed. Charts were smoothed using the gamlss non-linear regression method. The population-based approach, using bias-free ultrasound gestational age, produces stable estimates of size-for-age and weight-for-age curves in the range 24-42 weeks' gestation. There is a close correspondence between percentage deviations and percentiles of birth weight by gestational age, making it easy to convert between the two. The variance of birth weight that can be 'explained' by ultrasound increases from 8% at 20 weeks up to 67% around term. Intrauterine estimated fetal weight is 0-106 g higher than median birth weight in the preterm period. The new population-based birth-weight prediction model provides a simple summary measure, the 'percentage birth-weight deviation', to be used for fetal size monitoring throughout the third trimester. Predictive quality of the model can be measured directly from the population data. The model computes both median observed birth weight and intrauterine estimated fetal weight. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2016 ISUOG. Published by John

  4. How to control chaotic behaviour and population size with proportional feedback

    Energy Technology Data Exchange (ETDEWEB)

    Liz, Eduardo, E-mail: eliz@dma.uvigo.e [Departamento de Matematica Aplicada II, E.T.S.E. Telecomunicacion, Universidade de Vigo, Campus Marcosende, 36310 Vigo (Spain)

    2010-01-18

    We study the control of chaos in one-dimensional discrete maps as they often occur in modelling population dynamics. For managing the population, we seek to suppress any possible chaotic behavior, leading the system to a stable equilibrium. In this Letter, we make a rigorous analysis of the proportional feedback method under certain conditions fulfilled by a wide family of maps. We show that it is possible to stabilize the chaotic dynamics towards a globally stable positive equilibrium, that can be chosen among a broad range of possible values. In particular, the size of the population can be enhanced by control in form of population reduction. This paradoxical phenomenon is known as the hydra effect, and it has important implications in the design of strategies in such areas as fishing, pest management, and conservation biology.

  5. How to control chaotic behaviour and population size with proportional feedback

    International Nuclear Information System (INIS)

    Liz, Eduardo

    2010-01-01

    We study the control of chaos in one-dimensional discrete maps as they often occur in modelling population dynamics. For managing the population, we seek to suppress any possible chaotic behavior, leading the system to a stable equilibrium. In this Letter, we make a rigorous analysis of the proportional feedback method under certain conditions fulfilled by a wide family of maps. We show that it is possible to stabilize the chaotic dynamics towards a globally stable positive equilibrium, that can be chosen among a broad range of possible values. In particular, the size of the population can be enhanced by control in form of population reduction. This paradoxical phenomenon is known as the hydra effect, and it has important implications in the design of strategies in such areas as fishing, pest management, and conservation biology.

  6. Understanding and estimating effective population size for practical application in marine species management.

    Science.gov (United States)

    Hare, Matthew P; Nunney, Leonard; Schwartz, Michael K; Ruzzante, Daniel E; Burford, Martha; Waples, Robin S; Ruegg, Kristen; Palstra, Friso

    2011-06-01

    Effective population size (N(e)) determines the strength of genetic drift in a population and has long been recognized as an important parameter for evaluating conservation status and threats to genetic health of populations. Specifically, an estimate of N(e) is crucial to management because it integrates genetic effects with the life history of the species, allowing for predictions of a population's current and future viability. Nevertheless, compared with ecological and demographic parameters, N(e) has had limited influence on species management, beyond its application in very small populations. Recent developments have substantially improved N(e) estimation; however, some obstacles remain for the practical application of N(e) estimates. For example, the need to define the spatial and temporal scale of measurement makes the concept complex and sometimes difficult to interpret. We reviewed approaches to estimation of N(e) over both long-term and contemporary time frames, clarifying their interpretations with respect to local populations and the global metapopulation. We describe multiple experimental factors affecting robustness of contemporary N(e) estimates and suggest that different sampling designs can be combined to compare largely independent measures of N(e) for improved confidence in the result. Large populations with moderate gene flow pose the greatest challenges to robust estimation of contemporary N(e) and require careful consideration of sampling and analysis to minimize estimator bias. We emphasize the practical utility of estimating N(e) by highlighting its relevance to the adaptive potential of a population and describing applications in management of marine populations, where the focus is not always on critically endangered populations. Two cases discussed include the mechanisms generating N(e) estimates many orders of magnitude lower than census N in harvested marine fishes and the predicted reduction in N(e) from hatchery-based population

  7. Geographical patterns of Kaposi's sarcoma, nonHodgkin lymphomas, and cervical cancer associated with HIV infection in five African populations.

    Science.gov (United States)

    Chaabna, Karima; Boniol, Mathieu; de Vuyst, Hugo; Vanhems, Philippe; Antônio de Ávila Vitoria, Marco; Curado, Maria-Paula

    2012-01-01

    The objective of this study is to describe the most recent geographical patterns of incidence of AIDS-related cancers, Kaposi's sarcoma (KS), nonHodgkin lymphoma (NHL), and cervical cancer in North African and subSaharan African populations. Data were extracted for the period 1998-2002 from five African population-based cancer registries: Kyadondo, Harare, Setif, Sousse, and Gharbiah. Age-standardized rates were calculated using the African standard population; a comparison was made between these populations by computing the standardized incidence ratio and 95% confidence intervals. The KS rate was found to be significantly higher in men than in women, and higher in Harare (women: 26.3/100,000; men: 50.4/100,000) and Kyadondo (women: 23.6/100,000; men: 30.2/100,000) than in the North African sites for both sexes (HIV/AIDS (15-49 years), and these rates were 4.5-fold higher in subSaharan populations than those in the North African sites. Thus, it was observed that the pattern of HIV prevalence is variable with the lowest prevalence in North African countries, intermediate prevalence in Uganda, and the highest prevalence in Zimbabwe. Our findings show that the incidence of NHL and cervical cancer, considered to be HIV/AIDS-related cancers, does not follow the pattern of HIV prevalence in the five studied African populations. Thus, the highest NHL incidence rate in both sexes in Gambia may be explained, at least in great part, by the highest hepatitis C virus prevalence observed there. Indeed, factors other than HIV infection likely contribute to their geographical patterns.

  8. Low doses of six toxicants change plant size distribution in dense populations of Lactuca sativa.

    Science.gov (United States)

    Belz, Regina G; Patama, Marjo; Sinkkonen, Aki

    2018-08-01

    Toxicants are known to have negligible or stimulatory, i.e. hormetic, effects at low doses below those that decrease the mean response of a plant population. Our earlier observations indicated that at such low toxicant doses the growth of very fast- and slow-growing seedlings is selectively altered, even if the population mean remains constant. Currently, it is not known how common these selective low-dose effects are, whether they are similar among fast- and slow-growing seedlings, and whether they occur concurrently with hormetic effects. We tested the response of Lactuca sativa in complete dose-response experiments to six different toxicants at doses that did not decrease population mean and beyond. The tested toxicants were IAA, parthenin, HHCB, 4-tert-octylphenol, glyphosate, and pelargonic acid. Each experiment consisted of 14,400-16,800 seedlings, 12-14 concentrations, 24 replicates per concentration and 50 germinated seeds per replicate. We analyzed the commonness of selective low-dose effects and explored if toxic effects and hormetic stimulation among fast- and slow-growing individuals occurred at the same concentrations as they occur at the population level. Irrespective of the observed response pattern and toxicant, selective low-dose effects were found. Toxin effects among fast-growing individuals usually started at higher doses compared to the population mean, while the opposite was found among slow-growing individuals. Very low toxin exposures tended to homogenize plant populations due to selective effects, while higher, but still hormetic doses tended to heterogenize plant populations. Although the extent of observed size segregation varied with the specific toxin tested, we conclude that a dose-dependent alteration in size distribution of a plant population may generally apply for many toxin exposures. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Tobacco smoking in HIV-infected versus general population in france: heterogeneity across the various groups of people living with HIV.

    Science.gov (United States)

    Tron, Laure; Lert, France; Spire, Bruno; Dray-Spira, Rosemary

    2014-01-01

    Although the various groups of people living with HIV (PLWHIV) considerably differ regarding socioeconomic and behavioral characteristics, their specificities regarding tobacco smoking have been poorly investigated. We aimed to assess patterns of tobacco consumption across the various groups of PLWHIV and to compare them to the general population, accounting for the specific socioeconomic profile of PLWHIV. We used data of the ANRS-Vespa2 study, a national representative survey on PLWHIV conducted in France in 2011. Prevalence of past and current tobacco consumption, heavy smoking and strong nicotine dependence were assessed among the various groups of PLWHIV as defined by transmission category, gender and geographic origin, and compared to the French general population using direct standardization and multivariate Poisson regression models, accounting for gender, age, education and geographic origin. Among the 3,019 participants aged 18-85 years (median time since HIV diagnosis: 12 years), 37.5% were current smokers and 22.1% were past smokers, with marked differences across the various groups of PLWHIV. Compared to the general population, the prevalence of regular smoking was increased among HIV-infected men who have sex with men (MSM) (adjusted prevalence rate ratio (aPRR): 1.19, 95% confidence interval (95% CI): 1.07-1.32), French-native women (aPRR: 1.32, 95% CI: 1.10-1.57), and heterosexual French-native men (although not significantly, aPRR: 1.19, 95% CI: 0.98-1.45). Additionally, HIV-infected MSM were significantly less likely to be ex-smokers (aPRR: 0.73, 95% CI: 0.64-0.82) than the general population and similar trends were observed among heterosexual French-native men (aPRR: 0.89, 95% CI: 0.78-1.02) and women (aPRR: 0.84, 95% CI: 0.70-1.01). HIV-infected sub-Saharan African migrants were less likely to be regular smokers than the general population. Smoking constitutes a major concern in various groups of PLWHIV in France including MSM and heterosexual

  10. Tobacco smoking in HIV-infected versus general population in france: heterogeneity across the various groups of people living with HIV.

    Directory of Open Access Journals (Sweden)

    Laure Tron

    Full Text Available BACKGROUND: Although the various groups of people living with HIV (PLWHIV considerably differ regarding socioeconomic and behavioral characteristics, their specificities regarding tobacco smoking have been poorly investigated. We aimed to assess patterns of tobacco consumption across the various groups of PLWHIV and to compare them to the general population, accounting for the specific socioeconomic profile of PLWHIV. METHODS: We used data of the ANRS-Vespa2 study, a national representative survey on PLWHIV conducted in France in 2011. Prevalence of past and current tobacco consumption, heavy smoking and strong nicotine dependence were assessed among the various groups of PLWHIV as defined by transmission category, gender and geographic origin, and compared to the French general population using direct standardization and multivariate Poisson regression models, accounting for gender, age, education and geographic origin. RESULTS: Among the 3,019 participants aged 18-85 years (median time since HIV diagnosis: 12 years, 37.5% were current smokers and 22.1% were past smokers, with marked differences across the various groups of PLWHIV. Compared to the general population, the prevalence of regular smoking was increased among HIV-infected men who have sex with men (MSM (adjusted prevalence rate ratio (aPRR: 1.19, 95% confidence interval (95% CI: 1.07-1.32, French-native women (aPRR: 1.32, 95% CI: 1.10-1.57, and heterosexual French-native men (although not significantly, aPRR: 1.19, 95% CI: 0.98-1.45. Additionally, HIV-infected MSM were significantly less likely to be ex-smokers (aPRR: 0.73, 95% CI: 0.64-0.82 than the general population and similar trends were observed among heterosexual French-native men (aPRR: 0.89, 95% CI: 0.78-1.02 and women (aPRR: 0.84, 95% CI: 0.70-1.01. HIV-infected sub-Saharan African migrants were less likely to be regular smokers than the general population. CONCLUSIONS: Smoking constitutes a major concern in various groups

  11. Estimating effective population size from linkage disequilibrium between unlinked loci: theory and application to fruit fly outbreak populations.

    Directory of Open Access Journals (Sweden)

    John A Sved

    Full Text Available There is a substantial literature on the use of linkage disequilibrium (LD to estimate effective population size using unlinked loci. The Ne estimates are extremely sensitive to the sampling process, and there is currently no theory to cope with the possible biases. We derive formulae for the analysis of idealised populations mating at random with multi-allelic (microsatellite loci. The 'Burrows composite index' is introduced in a novel way with a 'composite haplotype table'. We show that in a sample of diploid size S, the mean value of x2 or r2 from the composite haplotype table is biased by a factor of 1-1/(2S-12, rather than the usual factor 1+1/(2S-1 for a conventional haplotype table. But analysis of population data using these formulae leads to Ne estimates that are unrealistically low. We provide theory and simulation to show that this bias towards low Ne estimates is due to null alleles, and introduce a randomised permutation correction to compensate for the bias. We also consider the effect of introducing a within-locus disequilibrium factor to r2, and find that this factor leads to a bias in the Ne estimate. However this bias can be overcome using the same randomised permutation correction, to yield an altered r2 with lower variance than the original r2, and one that is also insensitive to null alleles. The resulting formulae are used to provide Ne estimates on 40 samples of the Queensland fruit fly, Bactrocera tryoni, from populations with widely divergent Ne expectations. Linkage relationships are known for most of the microsatellite loci in this species. We find that there is little difference in the estimated Ne values from using known unlinked loci as compared to using all loci, which is important for conservation studies where linkage relationships are unknown.

  12. Estimating effective population size from linkage disequilibrium between unlinked loci: theory and application to fruit fly outbreak populations.

    Science.gov (United States)

    Sved, John A; Cameron, Emilie C; Gilchrist, A Stuart

    2013-01-01

    There is a substantial literature on the use of linkage disequilibrium (LD) to estimate effective population size using unlinked loci. The Ne estimates are extremely sensitive to the sampling process, and there is currently no theory to cope with the possible biases. We derive formulae for the analysis of idealised populations mating at random with multi-allelic (microsatellite) loci. The 'Burrows composite index' is introduced in a novel way with a 'composite haplotype table'. We show that in a sample of diploid size S, the mean value of x2 or r2 from the composite haplotype table is biased by a factor of 1-1/(2S-1)2, rather than the usual factor 1+1/(2S-1) for a conventional haplotype table. But analysis of population data using these formulae leads to Ne estimates that are unrealistically low. We provide theory and simulation to show that this bias towards low Ne estimates is due to null alleles, and introduce a randomised permutation correction to compensate for the bias. We also consider the effect of introducing a within-locus disequilibrium factor to r2, and find that this factor leads to a bias in the Ne estimate. However this bias can be overcome using the same randomised permutation correction, to yield an altered r2 with lower variance than the original r2, and one that is also insensitive to null alleles. The resulting formulae are used to provide Ne estimates on 40 samples of the Queensland fruit fly, Bactrocera tryoni, from populations with widely divergent Ne expectations. Linkage relationships are known for most of the microsatellite loci in this species. We find that there is little difference in the estimated Ne values from using known unlinked loci as compared to using all loci, which is important for conservation studies where linkage relationships are unknown.

  13. Risk of cerebrovascular events in persons with and without HIV: A Danish nationwide population-based cohort study

    DEFF Research Database (Denmark)

    Rasmussen, Line D; Engsig, Frederik Neess; Christensen, Hanne

    2011-01-01

    OBJECTIVE:: To assess the risk of cerebrovascular events (CVE) in HIV-infected individuals and evaluate the impact of proven risk factors, injection drug abuse (IDU), immunodeficiency, highly active antiretroviral therapy (HAART) and family-related risk factors. DESIGN:: Nationwide, population...

  14. Designing global collective action in population and HIV/AIDS programs, 1983-2002: has anything changed?

    NARCIS (Netherlands)

    van Dalen, H.P.

    2008-01-01

    The 1994 International Conference of Population and Development (ICPD) in Cairo established goals for the expansion of assistance in matters of reproductive health and HIV/AIDS. This global effort marked a structural break in principle from the past, but did it also change funding behavior? Panel

  15. Migratory divides and their consequences for dispersal, population size and parasite-host interactions.

    Science.gov (United States)

    Møller, A P; Garamszegi, L Z; Peralta-Sánchez, J M; Soler, J J

    2011-08-01

    Populations of migratory birds differ in their direction of migration with neighbouring populations often migrating in divergent directions separated by migratory divides. A total of 26% of 103 passerine bird species in Europe had migratory divides that were located disproportionately often along a longitudinal gradient in Central Europe, consistent with the assumption of a Quaternary glacial origin of such divides in the Iberian and Balkan peninsulas followed by recolonization. Given that studies have shown significant genetic differentiation and reduced gene flow across migratory divides, we hypothesized that an absence of migratory divides would result in elevated rates of gene flow and hence a reduced level of local adaptation. In a comparative study, species with migratory divides had larger population sizes and population densities and longer dispersal distances than species without migratory divides. Species with migratory divides tended to be habitat generalists. Bird species with migratory divides had higher richness of blood parasites and higher growth rates of Staphylococcus on their eggs during the incubation period. There was weaker cell-mediated immunity in adults and stronger cell lysis in species with migratory divides. These findings may suggest that migratory divides constitute barriers to dispersal with consequences for ecology and evolution of distributions, population sizes, habitats and parasite-host interactions. They also suggest that migratory divides may play a role in local adaptation in host-parasite interactions. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

  16. Early Warning Indicators for Population-Based Monitoring of HIV Drug Resistance in 6 African Countries

    NARCIS (Netherlands)

    Sigaloff, Kim C. E.; Hamers, Raph L.; Menke, Jack; Labib, Moheb; Siwale, Margaret; Ive, Prudence; Botes, Mariette E.; Kityo, Cissy; Mandaliya, Kishor; Wellington, Maureen; Osibogun, Akin; Geskus, Ronald B.; Stevens, Wendy S.; van Vugt, Michèle; Rinke de Wit, Tobias F.

    2012-01-01

    Human immunodeficiency virus (HIV) RNA testing and HIV drug resistance (HIVDR) testing are not routinely available for therapeutic monitoring of patients receiving antiretroviral therapy (ART) in resource-limited settings. World Health Organization HIVDR early warning indicators (EWIs) assess ART

  17. Antiretroviral treatment knowledge and stigma--implications for programs and HIV treatment interventions in rural Tanzanian populations.

    Directory of Open Access Journals (Sweden)

    Abela Mpobela Agnarson

    Full Text Available OBJECTIVE: To analyse antiretroviral treatment (ART knowledge and HIV- and ART-related stigma among the adult population in a rural Tanzanian community. DESIGN: Population-based cross-sectional survey of 694 adults (15-49 years of age. METHODS: Latent class analysis (LCA categorized respondents' levels of ART knowledge and of ART-related stigma. Multinomial logistic regression assessed the association between the levels of ART knowledge and HIV- and ART-related stigma, while controlling for the effects of age, gender, education, marital status and occupation. RESULTS: More than one-third of men and women in the study reported that they had never heard of ART. Among those who had heard of ART, 24% were east informed about ART, 8% moderately informed, and 68% highly informed. Regarding ART-related stigma, 28% were least stigmatizing, 41% moderately stigmatizing, and 31% highly stigmatizing toward persons taking ART. Respondents that had at least primary education were more likely to have high levels of knowledge about ART (OR 3.09, 95% CI 1.61-5.94. Participants highly informed about ART held less HIV- and ART-related stigma towards ART patients (OR 0.26, 95% CI 0.09-0.74. CONCLUSION: The lack of ART knowledge is broad, and there is a strong association between ART knowledge and individual education level. These are relevant findings for both HIV prevention and HIV treatment program interventions that address ART-related stigma across the entire spectrum of the community.

  18. HIV-1 transmission patterns in antiretroviral therapy-naive, HIV-infected North Americans based on phylogenetic analysis by population level and ultra-deep DNA sequencing.

    Directory of Open Access Journals (Sweden)

    Lisa L Ross

    Full Text Available Factors that contribute to the transmission of human immunodeficiency virus type 1 (HIV-1, especially drug-resistant HIV-1 variants remain a significant public health concern. In-depth phylogenetic analyses of viral sequences obtained in the screening phase from antiretroviral-naïve HIV-infected patients seeking enrollment in EPZ108859, a large open-label study in the USA, Canada and Puerto Rico (ClinicalTrials.gov NCT00440947 were examined for insights into the roles of drug resistance and epidemiological factors that could impact disease dissemination. Viral transmission clusters (VTCs were initially predicted from a phylogenetic analysis of population level HIV-1 pol sequences obtained from 690 antiretroviral-naïve subjects in 2007. Subsequently, the predicted VTCs were tested for robustness by ultra deep sequencing (UDS using pyrosequencing technology and further phylogenetic analyses. The demographic characteristics of clustered and non-clustered subjects were then compared. From 690 subjects, 69 were assigned to 1 of 30 VTCs, each containing 2 to 5 subjects. Race composition of VTCs were significantly more likely to be white (72% vs. 60%; p = 0.04. VTCs had fewer reverse transcriptase and major PI resistance mutations (9% vs. 24%; p = 0.002 than non-clustered sequences. Both men-who-have-sex-with-men (MSM (68% vs. 48%; p = 0.001 and Canadians (29% vs. 14%; p = 0.03 were significantly more frequent in VTCs than non-clustered sequences. Of the 515 subjects who initiated antiretroviral therapy, 33 experienced confirmed virologic failure through 144 weeks while only 3/33 were from VTCs. Fewer VTCs subjects (as compared to those with non-clustering virus had HIV-1 with resistance-associated mutations or experienced virologic failure during the course of the study. Our analysis shows specific geographical and drug resistance trends that correlate well with transmission clusters defined by HIV sequences of similarity

  19. Community patterns of stigma towards persons living with HIV: A population-based latent class analysis from rural Vietnam

    LENUS (Irish Health Repository)

    Pharris, Anastasia

    2011-09-18

    Abstract Background The negative effects of stigma on persons living with HIV (PLHIV) have been documented in many settings and it is thought that stigma against PLHIV leads to more difficulties for those who need to access HIV testing, treatment and care, as well as to limited community uptake of HIV prevention and testing messages. In order to understand and prevent stigma towards PLHIV, it is important to be able to measure stigma within communities and to understand which factors are associated with higher stigma. Methods To analyze patterns of community stigma and determinants to stigma toward PLHIV, we performed an exploratory population-based survey with 1874 randomly sampled adults within a demographic surveillance site (DSS) in rural Vietnam. Participants were interviewed regarding knowledge of HIV and attitudes towards persons living with HIV. Data were linked to socioeconomic and migration data from the DSS and latent class analysis and multinomial logistic regression were conducted to examine stigma group sub-types and factors associated with stigma group membership. Results We found unexpectedly high and complex patterns of stigma against PLHIV in this rural setting. Women had the greatest odds of belong to the highest stigma group (OR 1.84, 95% CI 1.42-2.37), while those with more education had lower odds of highest stigma group membership (OR 0.45, 95% CI 0.32-0.62 for secondary education; OR 0.19, 95% CI 0.10-0.35 for tertiary education). Long-term migration out of the district (OR 0.61, 95% CI 0.4-0.91), feeling at-risk for HIV (OR 0.42, 95% CI 0.27-0.66), having heard of HIV from more sources (OR 0.44, 95% CI 0.3-0.66), and knowing someone with HIV (OR 0.76, 95% CI 0.58-0.99) were all associated with lower odds of highest stigma group membership. Nearly 20% of the population was highly unsure of their attitudes towards PLHIV and persons in this group had significantly lower odds of feeling at-risk for HIV (OR 0.54, 95% CI 0.33-0.90) or of knowing

  20. 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....

  1. Designs and Methods for Association Studies and Population Size Inference in Statistical Genetics

    DEFF Research Database (Denmark)

    Waltoft, Berit Lindum

    method provides a simple goodness of t test by comparing the observed SFS with the expected SFS under a given model of population size changes. By the use of Monte Carlo estimation the expected time between coalescent events can be estimated and the expected SFS can thereby be evaluated. Using......). The OR is interpreted as the eect of an exposure on the probability of being diseased at the end of follow-up, while the interpretation of the IRR is the eect of an exposure on the probability of becoming diseased. Through a simulation study, the OR from a classical case-control study is shown to be an inconsistent...... the classical chi-square statistics we are able to infer single parameter models. Multiple parameter models, e.g. multiple epochs, are harder to identify. By introducing the inference of population size back in time as an inverse problem, the second procedure applies the theory of smoothing splines to infer...

  2. Four types of interference competition and their impacts on the ecology and evolution of size-structured populations and communities

    DEFF Research Database (Denmark)

    Zhang, Lai; Andersen, Ken Haste; Dieckmann, Ulf

    2015-01-01

    We investigate how four types of interference competition - which alternatively affect foraging, metabolism, survival, and reproduction - impact the ecology and evolution of size-structured populations. Even though all four types of interference competition reduce population biomass, interference...

  3. Variability in permanent tooth size of three ancient populations in Xi'an, northern China.

    Science.gov (United States)

    Huang, Shi-You; Kang, Ting; Liu, Dai-Yun; Duan, Yin-Zhong; Shao, Jin-Ling

    2012-11-01

    This paper compares permanent dental dimensions between three ancient populations that belonged to the same biological population throughout a temporal range of 2000 years to detect temporal trends and metric variation in dentition. The samples analysed were dental remains of 4502 permanent teeth from 321 individuals, which were excavated from three archaeological sites: Chang'an (1000-1300 years BP), Shanren (2200 years BP) and Shaolingyuan (3000 years BP) in the Xi'an region (northern China). For each tooth three standard measurements were taken: Mesiodistal (MD) diameter of crown, labiolingual or buccolingual (BL) diameter of crown and length of root (LR). Three ancient population samples generally displayed the same dental dimensions (p>0.05), whereas some tooth types varied. The Shaolingyuan had larger canine and the smallest maxillary second molars and the Chang'an had the largest mandibular first molars in the MD dimension. The Shanren had the smallest maxillary third molars and mandibular central incisors, and the Chang'an had the smallest maxillary lateral incisors in the BL dimension. In the LR measures, statistically significant differences of five tooth types showed that the Chang'an were smaller than the Shaolingyuan and the Shanren. Comparisons of coefficients of variation for teeth showed that the length of root and third molar usually displayed greater variation. Decreasing or increasing trend for crown size does not occur between the ancient populations, while changes in crown size of a few tooth types fluctuate. The root size is more variable than the crown size and is likely to reflect a degenerated trend in a few tooth types. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Asymptotic distributions of coalescence times and ancestral lineage numbers for populations with temporally varying size.

    Science.gov (United States)

    Chen, Hua; Chen, Kun

    2013-07-01

    The distributions of coalescence times and ancestral lineage numbers play an essential role in coalescent modeling and ancestral inference. Both exact distributions of coalescence times and ancestral lineage numbers are expressed as the sum of alternating series, and the terms in the series become numerically intractable for large samples. More computationally attractive are their asymptotic distributions, which were derived in Griffiths (1984) for populations with constant size. In this article, we derive the asymptotic distributions of coalescence times and ancestral lineage numbers for populations with temporally varying size. For a sample of size n, denote by Tm the mth coalescent time, when m + 1 lineages coalesce into m lineages, and An(t) the number of ancestral lineages at time t back from the current generation. Similar to the results in Griffiths (1984), the number of ancestral lineages, An(t), and the coalescence times, Tm, are asymptotically normal, with the mean and variance of these distributions depending on the population size function, N(t). At the very early stage of the coalescent, when t → 0, the number of coalesced lineages n - An(t) follows a Poisson distribution, and as m → n, $$n\\left(n-1\\right){T}_{m}/2N\\left(0\\right)$$ follows a gamma distribution. We demonstrate the accuracy of the asymptotic approximations by comparing to both exact distributions and coalescent simulations. Several applications of the theoretical results are also shown: deriving statistics related to the properties of gene genealogies, such as the time to the most recent common ancestor (TMRCA) and the total branch length (TBL) of the genealogy, and deriving the allele frequency spectrum for large genealogies. With the advent of genomic-level sequencing data for large samples, the asymptotic distributions are expected to have wide applications in theoretical and methodological development for population genetic inference.

  5. An Adaptive Genetic Algorithm with Dynamic Population Size for Optimizing Join Queries

    OpenAIRE

    Vellev, Stoyan

    2008-01-01

    The problem of finding the optimal join ordering executing a query to a relational database management system is a combinatorial optimization problem, which makes deterministic exhaustive solution search unacceptable for queries with a great number of joined relations. In this work an adaptive genetic algorithm with dynamic population size is proposed for optimizing large join queries. The performance of the algorithm is compared with that of several classical non-determinis...

  6. Predation and physical environment structure the density and population size structure of zebra mussels

    OpenAIRE

    Naddafi, Rahmat; Pettersson, Kurt; Eklöv, Peter

    2010-01-01

    The zebra mussel (Dreissena polymorpha) provides one example of successful invaders in novel environments. However, little attention has been devoted to exploring the factors regulating zebra mussel density and population size structure at the local scale. We tested effects of physicochemical factors and fish predation on the density of zebra mussels at several sites and between years in a natural lake. Water depth and roach (Rutilus rutilus) density were the most important variables affectin...

  7. 'If she is a good woman …' and 'to be a real man …': gender, risk and access to HIV services among key populations in Tajikistan.

    Science.gov (United States)

    King, Elizabeth J; Maksymenko, Kateryna M; Almodovar-Diaz, Yadira; Johnson, Sarah

    2016-01-01

    The HIV epidemic continues to grow in Tajikistan, especially among people who inject drugs, sex workers, men who have sex with men and incarcerated populations. Despite their susceptibility to HIV, members of these groups do not always have access to HIV prevention, testing and treatment. The purpose of this study was to identify and understand the gender constraints in accessing HIV services for key populations in Tajikistan. Using focus-group discussions and key-informant interviews the assessment team collected information from members of key populations and those who work with them. Several themes emerged from the data, including: low levels of HIV knowledge, gender constraints to condom use and safer drug use, gender constraints limit HIV testing opportunities, gender-based violence, stigma and discrimination, and the lack of female spaces in the HIV response. The results of this study show that there are well-defined gender norms in Tajikistan, and these gender norms influence key populations' access to HIV services. Addressing these gender constraints may offer opportunities for more equitable access to HIV services in Tajikistan.

  8. Group selection on population size affects life-history patterns in the entomopathogenic nematode Steinernema carpocapsae.

    Science.gov (United States)

    Bashey, Farrah; Lively, Curtis M

    2009-05-01

    Selection is recognized to operate on multiple levels. In disease organisms, selection among hosts is thought to provide an important counterbalance to selection for faster growth within hosts. We performed three experiments, each selecting for a divergence in group size in the entomopathogenic nematode, Steinernema carpocapsae. These nematodes infect and kill insect larvae, reproduce inside the host carcass, and emerge as infective juveniles. We imposed selection on group size by selecting among hosts for either high or low numbers of emerging nematodes. Our goal was to determine whether this trait could respond to selection at the group level, and if so, to examine what other traits would evolve as correlated responses. One of the three experiments showed a significant response to group selection. In that experiment, the high-selected treatment consistently produced more emerging nematodes per host than the low-selected treatment. In addition, nematodes were larger and they emerged later from hosts in the low-selected lines. Despite small effective population sizes, the effects of inbreeding were small in this experiment. Thus, selection among hosts can be effective, leading to both a direct evolutionary response at the population level, as well as to correlated responses in populational and individual traits.

  9. [Industrial waste as indicator of population size: possible utilization in mountain resort tourist stations?].

    Science.gov (United States)

    Olive, F; Rey, S; Zmirou, D

    1998-09-01

    Epidemiological studies, conducted in touristic resorts, often face the difficulty of assessing the size of the referent population. Recently, some population size indicators, have been tested. Among them, the amount of municipal waste seems to be easy and readily accessible. The purpose of the study is to describe how this indicator can be used in touristic mountain resorts. Four touristic resorts were chosen in Isère departement (France): Alpe d'Huez, Deux Alpes, Chamrousse, plateau du Vercors. The evolution of municipal waste over several years was used to compute an individual output level for residents and for tourists. This waste indicator was compared with data on tourists reservations in hotels in the resorts. We found a good fit during touristic seasons in three resorts (Spearman test). For the last one (Chamrousse), the correlation rate was low. We think that the type of tourism is different in this resort with many non residents. This indicator is reliable but needs further validation by sample surveys across several sites and several types of lodging. We propose to estimate the size of the referent population, based on an individual output of 1 kg per person and per day for residents and 0.5 kg per person per day for tourists.

  10. Population ecology of the mallard: II. Breeding habitat conditions, size of the breeding populations, and production indices

    Science.gov (United States)

    Pospahala, Richard S.; Anderson, David R.; Henny, Charles J.

    1974-01-01

    This report, the second in a series on a comprehensive analysis of mallard population data, provides information on mallard breeding habitat, the size and distribution of breeding populations, and indices to production. The information in this report is primarily the result of large-scale aerial surveys conducted during May and July, 1955-73. The history of the conflict in resource utilization between agriculturalists and wildlife conservation interests in the primary waterfowl breeding grounds is reviewed. The numbers of ponds present during the breeding season and the midsummer period and the effects of precipitation and temperature on the number of ponds present are analyzed in detail. No significant cycles in precipitation were detected and it appears that precipitation is primarily influenced by substantial seasonal and random components. Annual estimates (1955-73) of the number of mallards in surveyed and unsurveyed breeding areas provided estimates of the size and geographic distribution of breeding mallards in North America. The estimated size of the mallard breeding population in North America has ranged from a high of 14.4 million in 1958 to a low of 7.1 million in 1965. Generally, the mallard breeding population began to decline after the 1958 peak until 1962, and remained below 10 million birds until 1970. The decline and subsequent low level of the mallard population between 1959 and 1969 .generally coincided with a period of poor habitat conditions on the major breeding grounds. The density of mallards was highest in the Prairie-Parkland Area with an average of nearly 19.2 birds per square mile. The proportion of the continental mallard breeding population in the Prairie-Parkland Area ranged from 30% in 1962 to a high of 600/0 in 1956. The geographic distribution of breeding mallards throughout North America was significantly related to the number of May ponds in the Prairie-Parkland Area. Estimates of midsummer habitat conditions and indices to

  11. Optimal city size and population density for the 21st century.

    Science.gov (United States)

    Speare A; White, M J

    1990-10-01

    The thesis that large scale urban areas result in greater efficiency, reduced costs, and a better quality of life is reexamined. The environmental and social costs are measured for different scales of settlement. The desirability and perceived problems of a particular place are examined in relation to size of place. The consequences of population decline are considered. New York city is described as providing both opportunities in employment, shopping, and cultural activities as well as a high cost of living, crime, and pollution. The historical development of large cities in the US is described. Immigration has contributed to a greater concentration of population than would have otherwise have occurred. The spatial proximity of goods and services argument (agglomeration economies) has changed with advancements in technology such as roads, trucking, and electronic communication. There is no optimal city size. The overall effect of agglomeration can be assessed by determining whether the markets for goods and labor are adequate to maximize well-being and balance the negative and positive aspects of urbanization. The environmental costs of cities increase with size when air quality, water quality, sewage treatment, and hazardous waste disposal is considered. Smaller scale and lower density cities have the advantages of a lower concentration of pollutants. Also, mobilization for program support is easier with homogenous population. Lower population growth in large cities would contribute to a higher quality of life, since large metropolitan areas have a concentration of immigrants, younger age distributions, and minority groups with higher than average birth rates. The negative consequences of decline can be avoided if reduction of population in large cities takes place gradually. For example, poorer quality housing can be removed for open space. Cities should, however, still attract all classes of people with opportunities equally available.

  12. HIV-1 Adaptation to Antigen Processing Results in Population-Level Immune Evasion and Affects Subtype Diversification

    DEFF Research Database (Denmark)

    Tenzer, Stefan; Crawford, Hayley; Pymm, Phillip

    2014-01-01

    these regions encode epitopes presented by ~30 more common HLA variants. By combining epitope processing and computational analyses of the two HIV subtypes responsible for ~60% of worldwide infections, we identified a hitherto unrecognized adaptation to the antigen-processing machinery through substitutions...... of intrapatient adaptations, is predictable, facilitates viral subtype diversification, and increases global HIV diversity. Because low epitope abundance is associated with infrequent and weak T cell responses, this most likely results in both population-level immune evasion and inadequate responses in most...

  13. Real-Time Predictions of Reservoir Size and Rebound Time during Antiretroviral Therapy Interruption Trials for HIV.

    Directory of Open Access Journals (Sweden)

    Alison L Hill

    2016-04-01

    Full Text Available Monitoring the efficacy of novel reservoir-reducing treatments for HIV is challenging. The limited ability to sample and quantify latent infection means that supervised antiretroviral therapy (ART interruption studies are generally required. Here we introduce a set of mathematical and statistical modeling tools to aid in the design and interpretation of ART-interruption trials. We show how the likely size of the remaining reservoir can be updated in real-time as patients continue off treatment, by combining the output of laboratory assays with insights from models of reservoir dynamics and rebound. We design an optimal schedule for viral load sampling during interruption, whereby the frequency of follow-up can be decreased as patients continue off ART without rebound. While this scheme can minimize costs when the chance of rebound between visits is low, we find that the reservoir will be almost completely reseeded before rebound is detected unless sampling occurs at least every two weeks and the most sensitive viral load assays are used. We use simulated data to predict the clinical trial size needed to estimate treatment effects in the face of highly variable patient outcomes and imperfect reservoir assays. Our findings suggest that large numbers of patients-between 40 and 150-will be necessary to reliably estimate the reservoir-reducing potential of a new therapy and to compare this across interventions. As an example, we apply these methods to the two "Boston patients", recipients of allogeneic hematopoietic stem cell transplants who experienced large reductions in latent infection and underwent ART-interruption. We argue that the timing of viral rebound was not particularly surprising given the information available before treatment cessation. Additionally, we show how other clinical data can be used to estimate the relative contribution that remaining HIV+ cells in the recipient versus newly infected cells from the donor made to the

  14. Population size structure indices and growth standards for Salmo (trutta trutta Linnaeus, 1758 in Central Italy

    Directory of Open Access Journals (Sweden)

    Pedicillo G.

    2010-10-01

    Full Text Available The purpose of this study was to provide reference data on the growth and population structure of brown trout Salmo (trutta trutta Linnaeus, in Central Italy. Standards for growth (percentiles and a standard growth model were developed from the von Bertalanffy growth model by using length-at-age data obtained from 122 sampling sites in the River Tiber basin. Length-frequency indices provide a numeric estimation for deviations of the population structure from a balanced population. We adapted the traditional North American Relative Stock Density (RSD and Proportional Stock Density (PSD indices to brown trout populations in Central Italy by means of two methods. In the first method, the benchmarks of length categories were established by using percentages applied to the largest individual in the dataset. In the second method, asymptotic length and size at maturity were used to define the length categories for index calculation. Both methods were tested on length-frequency data from 263 sampling sites in the River Tiber basin. The results showed that the PSD calculated by the first method provided a better insight into the population structures of brown trout. These results provide tools that will help ichthyologists and fish managers to compare the growth and population structure of brown trout throughout Central Italy.

  15. Prevalence and factors associated with metabolic syndrome in an urban population of adults living with HIV in Nairobi, Kenya.

    Science.gov (United States)

    Kiama, Catherine Nduku; Wamicwe, Joyce Njeri; Oyugi, Elvis Omondi; Obonyo, Mark Odhiambo; Mungai, Jane Githuku; Roka, Zeinab Gura; Mwangi, Ann

    2018-01-01

    Metabolic syndrome affects 20-25% of the adult population globally. It predisposes to cardiovascular disease and Type 2 diabetes. Studies in other countries suggest a high prevalence of metabolic syndrome among HIV-infected patients but no studies have been reported in Kenya. The objective of this study was to assess the prevalence and factors associated with metabolic syndrome in adult HIV-infected patients in an urban population in Nairobi, Kenya. In a cross-sectional study design, conducted at Riruta Health Centre in 2016, 360 adults infected with HIV were recruited. A structured questionnaire was used to collect data on socio-demography. Blood was collected by finger prick for fasting glucose and venous sampling for lipid profile. Using the harmonized Joint Scientific Statement criteria, metabolic syndrome was present in 19.2%. The prevalence was higher among females than males (20.7% vs. 16.0%). Obesity (AOR = 5.37, P metabolic syndrome while physical activity (AOR = 0.28, P = 0.001) was associated with decreased odds. Metabolic syndrome is prevalent in this study population. Obesity, lack of formal education, family history of hypertension, and physical inactivity are associated with metabolic syndrome. Screening for risk factors, promotion of healthy lifestyle, and nutrition counselling should be offered routinely in HIV care and treatment clinics.

  16. Frequency of CCR5 Delta-32 Mutation in Human Immunodeficiency Virus (HIV-seropositive and HIV-exposed Seronegative Individuals and in General Population of Medellin, Colombia

    Directory of Open Access Journals (Sweden)

    Francisco J Díaz

    2000-04-01

    Full Text Available Repeated exposure to human immunodeficiency virus (HIV does not always result in seroconversion. Modifications in coreceptors for HIV entrance to target cells are one of the factors that block the infection. We studied the frequency of Delta-32 mutation in ccr5 gene in Medellin, Colombia. Two hundred and eighteen individuals distributed in three different groups were analyzed for Delta-32 mutation in ccr5 gene by polymerase chain reaction (PCR: 29 HIV seropositive (SP, 39 exposed seronegative (ESN and 150 individuals as a general population sample (GPS. The frequency of the Delta-32 mutant allele was 3.8% for ESN, 2.7% for GPS and 1.7% for SP. Only one homozygous mutant genotype (Delta-32/Delta-32 was found among the ESN (2.6%. The heterozygous genotype (ccr5/Delta-32 was found in eight GPS (5.3%, in one SP (3.4% and in one ESN (2.6%. The differences in the allelic and genotypic frequencies among the three groups were not statistically significant. A comparison between the expected and the observed genotypic frequencies showed that these frequencies were significantly different for the ESN group, which indirectly suggests a protective effect of the mutant genotype (Delta-32/Delta-32. Since this mutant genotype explained the resistance of infection in only one of our ESN persons, different mechanisms of protection must be playing a more important role in this population.

  17. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... contracting or transmitting HIV/AIDS or other infectious diseases. Research Reports: HIV/AIDS : Explores the link between drug misuse and HIV/AIDS, populations most at risk, trends in HIV/AIDS, and ...

  18. Extent of linkage disequilibrium and effective population size in four South African Sanga cattle breeds

    Directory of Open Access Journals (Sweden)

    Sithembile Olga Makina

    2015-12-01

    Full Text Available Knowledge on the extent of linkage disequilibrium (LD in livestock populations is essential to determine the minimum distance between markers required for effective coverage when conducting genome-wide association studies. This study evaluated the extent of LD, persistence of allelic phase and effective population size (Ne for four Sanga cattle breeds in South Africa including the Afrikaner (n=44, Nguni (n=54, Drakensberger (n=47 and Bonsmara breeds (n=46, using Angus (n=31 and Holstein (n=29 as reference populations. We found that moderate LD extends up to inter-marker distances of 40-60 kb in Angus (0.21 and Holstein (0.21 and up to 100 kb in Afrikaner (0.20. This suggests that genomic selection and association studies performed within these breeds using an average inter-marker r2 ≥ 0.20 would require about 30,000 -50,000 SNPs. However, r2 ≥ 0.20 extended only up to 10-20 kb in the Nguni and Drakensberger and 20-40 kb in the Bonsmara indicating that 75,000 to 150,000 SNPs would be necessary for genome-wide association studies in these breeds. Correlation between alleles at contiguous loci indicated that phase was not strongly preserved between breeds. This suggests the need for breed-specific reference populations in which a much greater density of markers should be scored to identify breed specific haplotypes which may then be imputed into multi-breed commercial populations. Analysis of effective population size based on the extent of LD, revealed Ne=95 (Nguni, Ne=87 (Drakensberger, Ne=77 (Bonsmara and Ne=41 (Afrikaner. Results of this study form the basis for implementation of genomic selection programs in the Sanga breeds of South Africa.

  19. 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.

  20. Measuring population transmission risk for HIV: an alternative metric of exposure risk in men who have sex with men (MSM in the US.

    Directory of Open Access Journals (Sweden)

    Colleen F Kelley

    Full Text Available Various metrics for HIV burden and treatment success [e.g. HIV prevalence, community viral load (CVL, population viral load (PVL, percent of HIV-positive persons with undetectable viral load] have important public health limitations for understanding disparities.Using data from an ongoing HIV incidence cohort of black and white men who have sex with men (MSM, we propose a new metric to measure the prevalence of those at risk of transmitting HIV and illustrate its value. MSM with plasma VL>400 copies/mL were defined as having 'transmission risk'. We calculated HIV prevalence, CVL, PVL, percent of HIV-positive with undetectable viral loads, and prevalence of plasma VL>400 copies/ml (%VL400 for black and white MSM. We used Monte Carlo simulation incorporating data on sexual mixing by race to estimate exposure of black and white HIV-negative MSM to a partner with transmission risk via unprotected anal intercourse (UAI. Of 709 MSM recruited, 42% (168/399 black and 14% (44/310 white MSM tested HIV-positive (p<.0001. No significant differences were seen in CVL, PVL, or percent of HIV positive with undetectable viral loads. The %VL400 was 25% (98/393 for black vs. 8% (25/310 for white MSM (p<.0001. Black MSM with 2 UAI partners were estimated to have 40% probability (95% CI: 35%, 45% of having ≥1 UAI partner with transmission risk vs. 20% for white MSM (CI: 15%, 24%.Despite similarities in other metrics, black MSM in our cohort are three times as likely as white MSM to have HIV transmission risk. With comparable risk behaviors, HIV-negative black MSM have a substantially higher likelihood of encountering a UAI partner at risk of transmitting HIV. Our results support increasing HIV testing, linkage to care, and antiretroviral treatment of HIV-positive MSM to reduce prevalence of those with transmission risk, particularly for black MSM.

  1. Somatic populations of PGT135-137 HIV-1-neutralizing antibodies identified by 454 pyrosequencing and bioinformatics

    Directory of Open Access Journals (Sweden)

    Jiang eZhu

    2012-09-01

    Full Text Available Select HIV-1-infected individuals develop sera capable of neutralizing diverse viral strains. The molecular basis of this neutralization is currently being deciphered by the isolation of HIV-1-neutralizing antibodies. In one infected donor, three neutralizing antibodies, PGT135-137, were identified by assessment of neutralization from individually sorted B cells and found to recognize an epitope containing an N-linked glycan at residue 332 on HIV-1 gp120. Here we use deep sequencing and bioinformatics methods to interrogate the B cell record of this donor to gain a more complete understanding of the humoral immune response. PGT135-137-gene family-specific primers were used to amplify heavy and light chain-variable domain sequences. 454 pyrosequencing produced 141,298 heavy-chain sequences of IGHV4-39 origin and 87,229 light-chain sequences of IGKV3-15 origin. A number of heavy and light chain sequences of ~90% identity to PGT137, several to PGT136, and none of high identity to PGT135 were identified. After expansion of these sequences to include close phylogenetic relatives, a total of 202 heavy-chain sequences and 72 light-chain sequences were identified. These sequences were clustered into populations of 95% identity comprising 15 for heavy chain and 10 for light chain, and a select sequence from each population was synthesized and reconstituted with a PGT137-partner chain. Reconstituted antibodies showed varied neutralization phenotypes for HIV-1 clade A and D isolates. Sequence diversity of the antibody population represented by these tested sequences was notably higher than observed with a 454 pyrosequencing-control analysis on 10 antibodies of defined sequence, suggesting that this diversity results primarily from somatic maturation. Our results thus provide an example of how pathogens like HIV-1 are opposed by a varied humoral immune response, derived from intrinsic mechanisms of antibody development, and embodied by somatic populations

  2. The effect of HIV/AIDS disease progression on spirituality and self-transcendence in a multicultural population.

    Science.gov (United States)

    Ramer, Lois; Johnson, Debra; Chan, Linda; Barrett, Mary Theresa

    2006-07-01

    This study examined the relationship of sociodemographic and clinical factors with spirituality and self-transcendence in people with HIV/AIDS. It involved 420 HIV/AIDS patients from an HIV clinic who were predominantly Hispanic (79%) and male (82%), with a mean age of 39 years. Subjects completed spirituality, self-transcendence, health status, and depression scales. Medical charts were reviewed to obtain demographics, current therapies, depression diagnosis, CD4 cells (sometimes called T-cells), and viral load levels. Self-transcendence was related to levels of energy (p self-transcendence or spirituality. The findings suggest the concept of self-transcendence may not be culturally meaningful to Hispanic patients. The development of valid and reliable tools specific for this population is important for future research.

  3. The Demand for Antiretroviral Drugs in the Illicit Marketplace: Implications for HIV Disease Management Among Vulnerable Populations.

    Science.gov (United States)

    Tsuyuki, Kiyomi; Surratt, Hilary L; Levi-Minzi, Maria A; O'Grady, Catherine L; Kurtz, Steven P

    2015-05-01

    The diversion of antiretroviral medications (ARVs) has implications for the integrity and success of HIV care, however little is known about the ARV illicit market. This paper aimed to identify the motivations for buying illicit ARVs and to describe market dynamics. Semi-structured interviews (n = 44) were conducted with substance-involved individuals living with HIV who have a history of purchasing ARVs on the street. Grounded theory was used to code and analyze interviews. Motivations for buying ARVs on the illicit market were: to repurchase ARVs after having diverted them for money or drugs; having limited access or low quality health care; to replace lost or ruined ARVs; and to buy a back-up stock of ARVs. This study identified various structural barriers to HIV treatment and ARV adherence that incentivized ARV diversion. Findings highlight the need to improve patient-provider relationships, ensure continuity of care, and integrate services to engage and retain high-needs populations.

  4. Felt Stigma in Injection Drug Users and Sex Workers: Focus Group Research with HIV-Risk Populations in Puerto Rico.

    Science.gov (United States)

    Jiménez, Julio; Puig, Marieva; Sala, Ana Cecilia; Ramos, Juan Carlos; Castro, Eida; Morales, Marangelie; Santiago, Lydia; Zorrilla, Carmen

    Though many studies have conclusively linked felt stigma and HIV, few have focused on the experiences of rejection felt by members of such socially marginalized groups as intravenous drug users (IDU) and sex workers (SW). Using focus groups, our study explored these experiences in 34 individuals (17 male UDUs and 17 female SWs) at risk of becoming infected with HIV, the objective being to discover why they engaged in maladaptive behaviors as a way of coping with felt stigma. We used deductive and inductive analysis to codify the resulting data. Concepts associated with the word stigma, emotional reactions to felt stigma, and the impact of felt stigma on self-schema helped elucidate how the internalization of felt stigma can lead to negative affective states and self-destructive behaviors (e.g., drug use and syringe exchange). Results underline the importance of developing intervention models that reduce stigma as a means of HIV prevention in vulnerable populations.

  5. [The organization of key populations connected to HIV transmission: an intervention to abate stigma; Mexico, 2005-2009].

    Science.gov (United States)

    Cuadra-Hernández, Silvia Magali; Zarco-Mera, Ángel; Infante-Xibillé, César; Caballero-García, Marta

    2012-01-01

    A qualitative and quantitative approach forms the base of this analysis of the results of "Vida Digna," a project aimed at abating stigma and discrimination in the HIV transmission field with actions taken by civil society organizations from 2005 to 2009 in the Mexican region of El Bajío. The results were analyzed in 2009 and 2010. The organizations involved were made up of key populations, defined as groups vulnerable to infection but also capable of resisting and controlling the transmission of HIV and the stigma and discrimination that are important barriers in the seeking of care and the achievement of effective HIV control. We describe and analyze the actions taken and the strengthening of the participating organizations. The visibility of new social actors such as transgender women and injecting drug users, as well as informative activities directed at journalists, the police and the military to prevent the criminalization and persecution of these groups, are highlighted.

  6. Spiritual care may impact mental health and medication adherence in HIV+ populations

    Directory of Open Access Journals (Sweden)

    Oji VU

    2017-04-01

    Full Text Available Valerie U Oji,1–3 Leslie C Hung,3 Reza Abbasgholizadeh,1,4 Flora Terrell Hamilton,5 E James Essien,6 Evaristus Nwulia7 1Lifefountain Center Ministries Inc, Houston, TX, USA; 2Feik School of Pharmacy, University of the Incarnate Word, San Antonio, TX, USA; 3University of Texas, College of Pharmacy, Austin, TX, USA; 4University of Houston, Houston, TX, USA; 5Administration, Family & Medical Counseling Service, Inc. (FMCS, Washington, DC, USA; 6University of Houston Institute for Community Health, Houston, TX, USA; 7Psychiatry, Howard University Translational Neuroscience Laboratory, Washington, DC, USA Objective: To explore a potential role for spirituality in medication-related needs assessment for integrated care in chronically ill populations. Method: A systematic literature review was conducted to explore the impact of faith beliefs on health and/or medication adherence in individuals with depression and/or HIV+/AIDS. Retrospective electronic medical record review of adult HIV+ patients of an urban primary care clinic with integrated mental health services was conducted, with Substance Abuse and Mental Illness Symptoms Screener (SAMISS, major depressive disorder (MDD incidence over the preceding year, and history of contact with a spiritual advisor. A convenience sample was interviewed to qualitatively assess potential medication therapy management needs and medication-related problems. Another sample was examined utilizing the Daily Spiritual Experience Scale. Results: The literature reports positive influence on health behaviors, coping and outcomes; and poor medication adherence and treatment decisions due to patient passivity or resistance. Spiritual advisor contact (not limited to a specific religion was significantly associated with MDD absence (1.7% vs. 15.3%, P<0.005 and inversely related to SAMISS, depression, and poor health behaviors. Patient interviews reflected significance of faith in terms of insight and acceptance of

  7. Population size and yield of Baffin Bay beluga (Delphinapterus leucas stocks

    Directory of Open Access Journals (Sweden)

    Stuart Innes

    2002-07-01

    Full Text Available A surplus production model within a Sampling, Importance Resampling (SIR Bayesian analysis was used to estimate stock sizes and yields of Baffin Bay belugas. The catch of belugas in West Greenland increased in 1968 and has remained well above sustainable rates. SIR analysis indicated a decline of about 50% between 1981 and 1994, with a credibility interval that included a previous estimate of 62%. The estimated stock sizes of belugas wintering off West Greenland in 1998 and 1999 were approximately 5,100 and 4,100 respectively and were not significantly different than an estimate based on aerial surveys combined for both years. Projected to 1999 this stock can sustain median landings of 109 whales with a total kill of about 155, based on posterior estimates of struck and lost plus under-reporting. The declining stock size index series did not provide sufficient information to estimate the potential maximum rate of population growth, the number of whales struck and lost, or the shape of the production curve with precision. Estimating these parameters requires an index time series with a marked step change in catch or a series with increasing stock sizes. The stock size estimate for the belugas wintering in the North Water in 1999 was approximately 14,800 but there is no information about the population biology of these whales. The estimated maximum sustainable yield (landed for the North Water stock was 317 belugas.

  8. Depression and HIV in Botswana: a population-based study on gender-specific socioeconomic and behavioral correlates.

    Directory of Open Access Journals (Sweden)

    Reshma Gupta

    2010-12-01

    Full Text Available Depression is a leading contributor to the burden of disease worldwide, a critical barrier to HIV prevention and a common serious HIV co-morbidity. However, depression screening and treatment are limited in sub-Saharan Africa, and there are few population-level studies examining the prevalence and gender-specific factors associated with depression.We conducted a cross-sectional population-based study of 18-49 year-old adults from five districts in Botswana with the highest prevalence of HIV-infection. We examined the prevalence of depressive symptoms, using a Hopkins Symptom Checklist for Depression (HSCL-D score of ≥ 1.75 to define depression, and correlates of depression using multivariate logistic regression stratified by sex.Of 1,268 participants surveyed, 25.3% of women and 31.4% of men had depression. Among women, lower education (adjusted odds ratio [AOR] 2.07, 95% confidence interval [1.30-3.32], higher income (1.77 [1.09-2.86], and lack of control in sexual decision-making (2.35 [1.46-3.81] were positively associated with depression. Among men, being single (1.95 [1.02-3.74], living in a rural area (1.63 [1.02-2.65], having frequent visits to a health provider (3.29 [1.88-5.74], anticipated HIV stigma (fearing discrimination if HIV status was revealed (2.04 [1.27-3.29], and intergenerational sex (2.28 [1.17-4.41] were independently associated with depression.Depression is highly prevalent in Botswana, and its correlates are gender-specific. Our findings suggest multiple targets for screening and prevention of depression and highlight the need to integrate mental health counseling and treatment into primary health care to decrease morbidity and improve HIV management efforts.

  9. Sociodemographic factors and prejudice toward HIV and hepatitis B/C status in a working-age population: results from a national, cross-sectional study in Japan.

    Science.gov (United States)

    Eguchi, Hisashi; Wada, Koji; Smith, Derek R

    2014-01-01

    In many countries, HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV) infected individuals may face discrimination and mistreatment from coworkers. Effective interventions to reduce workplace discrimination are therefore needed to protect these vulnerable populations. The current study investigated potential associations between sociodemographic factors and prejudice toward HIV and HBV/HCV infected colleagues within a Japanese working population. An online anonymous, nationwide internet survey was administered to a cross-section of approximately 3,000 individuals in Japan. The survey comprised 14 questions focusing on demographics (five items), basic HIV or HBV/HCV knowledge (eight items), and potential prejudice toward HIV or HBV/HCV infected colleagues (one item). The sociodemographic characteristics evaluated were sex, age, educational level, employment status, and individual income; with multiple logistic regression used for the analysis. In total, 3,055 individuals were recruited for the HIV related survey and 3,129 for the HBV/HCV related survey. Older age was significantly and positively associated with prejudice toward HIV infected colleagues (pprejudice toward HBV/HCV infected colleagues (pprejudice toward HIV and HBV/HCV infected coworkers. Overall, this study suggests that age may be associated with prejudice toward HIV and HBV/HCV infected colleagues among the working age population of Japan. As such, policy makers should consider the age of participants when formulating efforts to reduce prejudice toward HIV and HBV/HCV infected workers.

  10. Internalized HIV Stigma and Disclosure Concerns: Development and Validation of Two Scales in Spanish-Speaking Populations.

    Science.gov (United States)

    Hernansaiz-Garrido, Helena; Alonso-Tapia, Jesús

    2017-01-01

    Internalized stigma and disclosure concerns are key elements for the study of mental health in people living with HIV. Since no measures of these constructs were available for Spanish population, this study sought to develop such instruments, to analyze their reliability and validity and to provide a short version. A heterogeneous sample of 458 adults from different Spanish-speaking countries completed the HIV-Internalized Stigma Scale and the HIV-Disclosure Concerns Scale, along with the Hospital Anxiety and Depression Scale, Rosenberg's Self-esteem Scale and other socio-demographic variables. Reliability and correlation analyses, exploratory factor analyses, path analyses with latent variables, and ANOVAs were conducted to test the scales' psychometric properties. The scales showed good reliability in terms of internal consistency and temporal stability, as well as good sensitivity and factorial and criterion validity. The HIV-Internalized Stigma Scale and the HIV-Disclosure Concerns Scale are reliable and valid means to assess these variables in several contexts.

  11. Women Living with HIV over Age of 65: Cervical Cancer Screening in a Unique and Growing Population

    Directory of Open Access Journals (Sweden)

    Alexandra Aserlind

    2017-01-01

    Full Text Available Objective. Women living with HIV are at increased risk of human papillomavirus (HPV infection, which can lead to cervical cancer. New guidelines recommend indefinite screening. The objective of this study is to describe cervical cancer screening practices and colposcopy results in a cohort of women living with HIV over age of 65 who were followed before the new guidelines. Comorbidities, sexually transmitted infections (STIs, and other risk factors were evaluated. Methods. We conducted a retrospective chart review on 75 women aged 65 or older living with HIV with at least one Pap smear. Results. The mean age of the cohort was 66.5 and at HIV diagnosis was 56. The majority of women were immunocompetent. 80% had serial Pap smears. Of these, 86% of 238 were negative or ASCUS. No women progressed to HSIL. 92% of colposcopies had negative or CIN I results. Three women were treated successfully for high-grade dysplasia. More than half of women had other STIs. 72% were screened for HPV; 50% were positive. Conclusion. The majority of women had negative and low-grade Pap smears. Questions remain regarding the utility of continued Pap screening and the added value of HPV testing in this unique population of older women living with HIV.

  12. The cultural evolution of human communication systems in different sized populations: usability trumps learnability.

    Science.gov (United States)

    Fay, Nicolas; Ellison, T Mark

    2013-01-01

    This study examines the intergenerational transfer of human communication systems. It tests if human communication systems evolve to be easy to learn or easy to use (or both), and how population size affects learnability and usability. Using an experimental-semiotic task, we find that human communication systems evolve to be easier to use (production efficiency and reproduction fidelity), but harder to learn (identification accuracy) for a second generation of naïve participants. Thus, usability trumps learnability. In addition, the communication systems that evolve in larger populations exhibit distinct advantages over those that evolve in smaller populations: the learnability loss (from the Initial signs) is more muted and the usability benefits are more pronounced. The usability benefits for human communication systems that evolve in a small and large population is explained through guided variation reducing sign complexity. The enhanced performance of the communication systems that evolve in larger populations is explained by the operation of a content bias acting on the larger pool of competing signs. The content bias selects for information-efficient iconic signs that aid learnability and enhance usability.

  13. Estimating population size in wastewater-based epidemiology. Valencia metropolitan area as a case study.

    Science.gov (United States)

    Rico, María; Andrés-Costa, María Jesús; Picó, Yolanda

    2017-02-05

    Wastewater can provide a wealth of epidemiologic data on common drugs consumed and on health and nutritional problems based on the biomarkers excreted into community sewage systems. One of the biggest uncertainties of these studies is the estimation of the number of inhabitants served by the treatment plants. Twelve human urine biomarkers -5-hydroxyindoleacetic acid (5-HIAA), acesulfame, atenolol, caffeine, carbamazepine, codeine, cotinine, creatinine, hydrochlorothiazide (HCTZ), naproxen, salicylic acid (SA) and hydroxycotinine (OHCOT)- were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to estimate population size. The results reveal that populations calculated from cotinine, 5-HIAA and caffeine are commonly in agreement with those calculated by the hydrochemical parameters. Creatinine is too unstable to be applicable. HCTZ, naproxen, codeine, OHCOT and carbamazepine, under or overestimate the population compared to the hydrochemical population estimates but showed constant results through the weekdays. The consumption of cannabis, cocaine, heroin and bufotenine in Valencia was estimated for a week using different population calculations. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. The cultural evolution of human communication systems in different sized populations: usability trumps learnability.

    Directory of Open Access Journals (Sweden)

    Nicolas Fay

    Full Text Available This study examines the intergenerational transfer of human communication systems. It tests if human communication systems evolve to be easy to learn or easy to use (or both, and how population size affects learnability and usability. Using an experimental-semiotic task, we find that human communication systems evolve to be easier to use (production efficiency and reproduction fidelity, but harder to learn (identification accuracy for a second generation of naïve participants. Thus, usability trumps learnability. In addition, the communication systems that evolve in larger populations exhibit distinct advantages over those that evolve in smaller populations: the learnability loss (from the Initial signs is more muted and the usability benefits are more pronounced. The usability benefits for human communication systems that evolve in a small and large population is explained through guided variation reducing sign complexity. The enhanced performance of the communication systems that evolve in larger populations is explained by the operation of a content bias acting on the larger pool of competing signs. The content bias selects for information-efficient iconic signs that aid learnability and enhance usability.

  15. Integrating citizen-science data with movement models to estimate the size of a migratory golden eagle population

    Science.gov (United States)

    Andrew J. Dennhardt; Adam E. Duerr; David Brandes; Todd E. Katzner

    2015-01-01

    Estimating population size is fundamental to conservation and management. Population size is typically estimated using survey data, computer models, or both. Some of the most extensive and often least expensive survey data are those collected by citizen-scientists. A challenge to citizen-scientists is that the vagility of many organisms can complicate data collection....

  16. Effective population sizes of a major vector of human diseases, Aedes aegypti.

    Science.gov (United States)

    Saarman, Norah P; Gloria-Soria, Andrea; Anderson, Eric C; Evans, Benjamin R; Pless, Evlyn; Cosme, Luciano V; Gonzalez-Acosta, Cassandra; Kamgang, Basile; Wesson, Dawn M; Powell, Jeffrey R

    2017-12-01

    The effective population size ( N e ) is a fundamental parameter in population genetics that determines the relative strength of selection and random genetic drift, the effect of migration, levels of inbreeding, and linkage disequilibrium. In many cases where it has been estimated in animals, N e is on the order of 10%-20% of the census size. In this study, we use 12 microsatellite markers and 14,888 single nucleotide polymorphisms (SNPs) to empirically estimate N e in Aedes aegypti , the major vector of yellow fever, dengue, chikungunya, and Zika viruses. We used the method of temporal sampling to estimate N e on a global dataset made up of 46 samples of Ae. aegypti that included multiple time points from 17 widely distributed geographic localities. Our N e estimates for Ae. aegypti fell within a broad range (~25-3,000) and averaged between 400 and 600 across all localities and time points sampled. Adult census size (N c ) estimates for this species range between one and five thousand, so the N e / N c ratio is about the same as for most animals. These N e values are lower than estimates available for other insects and have important implications for the design of genetic control strategies to reduce the impact of this species of mosquito on human health.

  17. Mark-resight approach as a tool to estimate population size of one of the world’s smallest goose populations

    DEFF Research Database (Denmark)

    Clausen, Kevin Kuhlmann; Fælled, Casper Cæsar; Clausen, Preben

    2013-01-01

    The present study investigates the use of a mark–resight procedure to estimate total population size in a local goose population. Using colour-ring sightings of the increasingly scattered population of Light-bellied Brent Geese Branta bernicla hrota from their Danish staging areas, we estimate...... a total population size of 7845 birds (95% CI: 7252–8438). This is in good agreement with numbers obtained from total counts, emphasizing that this population, although steadily increasing, is still small compared with historic numbers....

  18. Compensatory immigration depends on adjacent population size and habitat quality but not on landscape connectivity.

    Science.gov (United States)

    Turgeon, Katrine; Kramer, Donald L

    2012-11-01

    1. Populations experiencing localized mortality can recover in the short term by net movement of individuals from adjacent areas, a process called compensatory immigration or spillover. Little is known about the factors influencing the magnitude of compensatory immigration or its impact on source populations. Such information is important for understanding metapopulation dynamics, the use of protected areas for conservation, management of exploited populations and pest control. 2. Using two small, territorial damselfish species (Stegastes diencaeus and S. adustus) in their naturally fragmented habitat, we quantified compensatory immigration in response to localized mortality, assessed its impact on adjacent source populations and examined the importance of potential immigrants, habitat quality and landscape connectivity as limiting factors. On seven experimental sites, we repeatedly removed 15% of the initial population size until none remained and immigration ceased. 3. Immigrants replaced 16-72% of original residents in S. diencaeus and 0-69% in S. adustus. The proportion of the source population that immigrated into depleted areas varied from 9% to 61% in S. diencaeus and from 3% to 21% in S. adustus. In S. diencaeus, compensatory immigration was strongly affected by habitat quality, to a lesser extent by the abundance of potential immigrants and not by landscape connectivity. In S. adustus, immigration was strongly affected by the density of potential migrants and not by habitat quality and landscape connectivity. On two control sites, immigration in the absence of creation of vacancies was extremely rare. 4. Immigration occurred in response to localized mortality and was therefore compensatory. It was highly variable, sometimes producing substantial impacts on both depleted and source populations. The magnitude of compensatory immigration was influenced primarily by the availability of immigrants and by the potential improvement in territory quality that they

  19. Trends in HIV testing and associated factors among men in South Africa: evidence from 2005, 2008 and 2012 national population-based household surveys.

    Science.gov (United States)

    Makusha, T; Mabaso, M; Richter, L; Desmond, C; Jooste, S; Simbayi, L

    2017-02-01

    In Sub-Saharan African countries, including South Africa, uptake of human immunodeficiency virus (HIV) testing among men remains a major challenge. Few studies have explored HIV testing uptake among men and factors that influence their testing behaviours. This article explores trends in HIV testing uptake and associated factors among men aged 15 years and older in South Africa using national HIV population-based household surveys conducted in 2005, 2008 and 2012. A multistage cross-sectional design was used in the three nationally representative household-based surveys. P-trend Chi-squared statistic was used to analyze changes in HIV testing in relation to demographic factors, and HIV-related risk behaviours across the three surveys. Univariate and multivariate logistic regression models were used to assess the associations between ever testing for HIV, demographic factors and HIV-related risk behaviours. HIV testing uptake among men was 28% in 2005, 43% in 2008 and 59% in 2012. A trend was also observed in HIV testing by sociodemographic factors, but differences existed within variables. HIV testing uptake was mainly influenced by the effects of selected population characteristics. Reduced likelihood of HIV testing was significantly associated with males aged 15-24 years, Black African race group, being single and unemployed, those residing in urban informal and rural informal areas, and those men who ever had sex. The observed sociodemographic differentials suggest that an effective expansion strategy for HIV testing needs to prioritize those most unlikely to test as identified by the current findings. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  20. Changing HIV treatment eligibility under health system constraints in sub-Saharan Africa: Investment needs, population health gains, and cost-effectiveness

    NARCIS (Netherlands)

    J.A.C. Hontelez (Jan); A.Y. Chang (Angela Y.); O. Ogbuoji (Osondu); S.J. de Vlas (Sake); T. Bärnighausen (Till); R. Atun (Rifat)

    2016-01-01

    markdownabstract__Objective:__ We estimated the investment needs, population health gains, and costeffectiveness of different policy options for scaling-up prevention and treatment of HIV in the 10 countries that currently comprise 80% of all people living with HIV in sub- Saharan Africa (Ethiopia,

  1. Sonographic determination of normal spleen size in an adult African population

    Energy Technology Data Exchange (ETDEWEB)

    Mustapha, Zainab; Tahir, Abdulrahman [Department of Radiology, University of Maiduguri Teaching Hospital, Maiduguri, Borno State (Nigeria); Tukur, Maisaratu [Department of Human Physiology, University of Maiduguri, Maiduguri, Borno State (Nigeria); Bukar, Mohammed [Department of Obstetrics and Gynaecology, University of Maiduguri Teaching Hospital, Maiduguri, Borno State (Nigeria); Lee, Wai-Kit, E-mail: leewk33@hotmail.co [Department of Medical Imaging, St. Vincent' s Hospital, University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065 (Australia)

    2010-07-15

    Objective: The purpose of this study was to determine the normal range of spleen size in an adult African population, and compare the findings to published data to determine any correlation with ethnicity. Materials and methods: Three hundred and seventy-four African adults without conditions that can affect the spleen or splenic abnormalities were evaluated with ultrasonography. Spleen length, width and thickness were measured and spleen volume calculated. Spleen size was correlated with age, gender, height, weight, and body mass index. Results: The mean spleen volume was 120 cm{sup 3}. Spleen volume correlated with spleen width (r = 0.85), thickness (r = 0.83) and length (r = 0.80). Men had a larger mean spleen volume than women. No correlation was found between spleen volume and age, weight, height, or body mass index. Conclusion: Mean spleen volume in African adults is smaller than data from Western sources, and cannot be explained by difference in body habitus.

  2. HIV-infection, atherosclerosis and the inflammatory pathway: candidate gene study in a Spanish HIV-infected population.

    Directory of Open Access Journals (Sweden)

    Laura Ibáñez

    Full Text Available BACKGROUND: Higher prevalence of atherosclerosis and higher cardiovascular risk is observed in HIV-infected individuals. The biological mechanisms underlying these processes are unclear. Several studies have implicated genetic variants in the inflammatory genes in cardiovascular disease and in HIV natural course infection. METHODS & FINDINGS: In this study we have tested the possible association between genetic variants in several inflammatory genes and asymptomatic cardiovascular disease measured by carotid intima media thickness (cIMT and atherosclerotic plaque presence as dependent variables in 213 HIV-infected individuals. A total of 101 genetic variants in 25 candidate genes have been genotyped. Results were analyzed using Plink and SPSS statistical packages. We have found several polymorphisms in the genes ALOX5 (rs2115819 p = 0.009, ALOX5AP (rs9578196 p = 0.007; rs4769873 p = 0.004 and rs9315051 p = 0.0004, CX3CL1 (rs4151117 p = 0.040 and rs614230 p = 0.015 and CCL5 (rs3817655 p = 0.018 and rs2107538 p = 0.018 associated with atherosclerotic plaque. cIMT mean has been associated with CRP (1130864 p = 0.0003 and rs1800947 p = 0.008, IL1RN (rs380092 p = 0.002 and ALOX5AP (rs3885907 p = 0.02 genetic variants. CONCLUSIONS: In this study we have found modest associations between genetic variants in several inflammatory genes and atherosclerotic plaque or cIMT. Nevertheless, our study adds evidence to the association between inflammatory pathway genetic variants and the atherosclerotic disease in HIV-infected individuals.

  3. mtDNA variation predicts population size in humans and reveals a major Southern Asian chapter in human prehistory.

    Science.gov (United States)

    Atkinson, Quentin D; Gray, Russell D; Drummond, Alexei J

    2008-02-01

    The relative timing and size of regional human population growth following our expansion from Africa remain unknown. Human mitochondrial DNA (mtDNA) diversity carries a legacy of our population history. Given a set of sequences, we can use coalescent theory to estimate past population size through time and draw inferences about human population history. However, recent work has challenged the validity of using mtDNA diversity to infer species population sizes. Here we use Bayesian coalescent inference methods, together with a global data set of 357 human mtDNA coding-region sequences, to infer human population sizes through time across 8 major geographic regions. Our estimates of relative population sizes show remarkable concordance with the contemporary regional distribution of humans across Africa, Eurasia, and the Americas, indicating that mtDNA diversity is a good predictor of population size in humans. Plots of population size through time show slow growth in sub-Saharan Africa beginning 143-193 kya, followed by a rapid expansion into Eurasia after the emergence of the first non-African mtDNA lineages 50-70 kya. Outside Africa, the earliest and fastest growth is inferred in Southern Asia approximately 52 kya, followed by a succession of growth phases in Northern and Central Asia (approximately 49 kya), Australia (approximately 48 kya), Europe (approximately 42 kya), the Middle East and North Africa (approximately 40 kya), New Guinea (approximately 39 kya), the Americas (approximately 18 kya), and a second expansion in Europe (approximately 10-15 kya). Comparisons of relative regional population sizes through time suggest that between approximately 45 and 20 kya most of humanity lived in Southern Asia. These findings not only support the use of mtDNA data for estimating human population size but also provide a unique picture of human prehistory and demonstrate the importance of Southern Asia to our recent evolutionary past.

  4. Long Term Population, City Size and Climate Trends in the Fertile Crescent: A First Approximation.

    Science.gov (United States)

    Lawrence, Dan; Philip, Graham; Hunt, Hannah; Snape-Kennedy, Lisa; Wilkinson, T J

    2016-01-01

    Over the last 8000 years the Fertile Crescent of the Near East has seen the emergence of urban agglomerations, small scale polities and large territorial empires, all of which had profound effects on settlement patterns. Computational approaches, including the use of remote sensing data, allow us to analyse these changes at unprecedented geographical and temporal scales. Here we employ these techniques to examine and compare long term trends in urbanisation, population and climate records. Maximum city size is used as a proxy for the intensity of urbanisation, whilst population trends are modelled from settlement densities in nine archaeological surveys conducted over the last 30 years across the region. These two measures are then compared with atmospheric moisture levels derived from multiple proxy analyses from two locations close to the study area, Soreq Cave in Israel and Lake Van in south-eastern Turkey, as well as wider literature. The earliest urban sites emerged during a period of relatively high atmospheric moisture levels and conform to a series of size thresholds. However, after the Early Bronze Age maximum urban size and population levels increase rapidly whilst atmospheric moisture declines. We argue that although the initial phase of urbanization may have been linked to climate conditions, we can see a definitive decoupling of climate and settlement patterns after 2000 BC. We relate this phenomenon to changes in socio-economic organisation and integration in large territorial empires. The complex relationships sustaining urban growth during this later period resulted in an increase in system fragility and ultimately impacted on the sustainability of cities in the long term.

  5. The relationship between settlement population size and sustainable development measured by two sustainability metrics

    International Nuclear Information System (INIS)

    O'Regan, Bernadette; Morrissey, John; Foley, Walter; Moles, Richard

    2009-01-01

    This paper reports on a study of the relative sustainability of 79 Irish villages, towns and a small city (collectively called 'settlements') classified by population size. Quantitative data on more than 300 economic, social and environmental attributes of each settlement were assembled into a database. Two aggregated metrics were selected to model the relative sustainability of settlements: Ecological Footprint (EF) and Sustainable Development Index (SDI). Subsequently these were aggregated to create a single Combined Sustainable Development Index. Creation of this database meant that metric calculations did not rely on proxies, and were therefore considered to be robust. Methods employed provided values for indicators at various stages of the aggregation process. This allowed both the first reported empirical analysis of the relationship between settlement sustainability and population size, and the elucidation of information provided at different stages of aggregation. At the highest level of aggregation, settlement sustainability increased with population size, but important differences amongst individual settlements were masked by aggregation. EF and SDI metrics ranked settlements in differing orders of relative sustainability. Aggregation of indicators to provide Ecological Footprint values was found to be especially problematic, and this metric was inadequately sensitive to distinguish amongst the relative sustainability achieved by all settlements. Many authors have argued that, for policy makers to be able to inform planning decisions using sustainability indicators, it is necessary that they adopt a toolkit of aggregated indicators. Here it is argued that to interpret correctly each aggregated metric value, policy makers also require a hierarchy of disaggregated component indicator values, each explained fully. Possible implications for urban planning are briefly reviewed

  6. Population size, center-periphery, and seed dispersers' effects on the genetic diversity and population structure of the Mediterranean relict shrub Cneorum tricoccon.

    Science.gov (United States)

    Lázaro-Nogal, Ana; Matesanz, Silvia; García-Fernández, Alfredo; Traveset, Anna; Valladares, Fernando

    2017-09-01

    The effect of population size on population genetic diversity and structure has rarely been studied jointly with other factors such as the position of a population within the species' distribution range or the presence of mutualistic partners influencing dispersal. Understanding these determining factors for genetic variation is critical for conservation of relict plants that are generally suffering from genetic deterioration. Working with 16 populations of the vulnerable relict shrub Cneorum tricoccon throughout the majority of its western Mediterranean distribution range, and using nine polymorphic microsatellite markers, we examined the effects of periphery (peripheral vs. central), population size (large vs. small), and seed disperser (introduced carnivores vs. endemic lizards) on the genetic diversity and population structure of the species. Contrasting genetic variation ( H E : 0.04-0.476) was found across populations. Peripheral populations showed lower genetic diversity, but this was dependent on population size. Large peripheral populations showed high levels of genetic diversity, whereas small central populations were less diverse. Significant isolation by distance was detected, indicating that the effect of long-distance gene flow is limited relative to that of genetic drift, probably due to high selfing rates ( F IS  = 0.155-0.887), restricted pollen flow, and ineffective seed dispersal. Bayesian clustering also supported the strong population differentiation and highly fragmented structure. Contrary to expectations, the type of disperser showed no significant effect on either population genetic diversity or structure. Our results challenge the idea of an effect of periphery per se that can be mainly explained by population size, drawing attention to the need of integrative approaches considering different determinants of genetic variation. Furthermore, the very low genetic diversity observed in several small populations and the strong among-population

  7. Hierarchical modelling of temperature and habitat size effects on population dynamics of North Atlantic cod

    DEFF Research Database (Denmark)

    Mantzouni, Irene; Sørensen, Helle; O'Hara, Robert B.

    2010-01-01

    and Beverton and Holt stock–recruitment (SR) models were extended by applying hierarchical methods, mixed-effects models, and Bayesian inference to incorporate the influence of these ecosystem factors on model parameters representing cod maximum reproductive rate and carrying capacity. We identified......Understanding how temperature affects cod (Gadus morhua) ecology is important for forecasting how populations will develop as climate changes in future. The effects of spawning-season temperature and habitat size on cod recruitment dynamics have been investigated across the North Atlantic. Ricker...

  8. Determinants of self-perceived risk of HIV infection: population-based observations in Zambia

    OpenAIRE

    Mwangala, Sheila Monde

    2008-01-01

    Background Perception of risk of HIV infection has been suggested to be an important area of study as it can be an assumed to be an indicator of one’s understanding of susceptibility to HIV infection and a precursor to behavioral change, which could determine future decision making regarding risk taking. Studies that have examined perception of HIV risk and its determinants still remain limited. Zambia is among the worst affected countries by the HIV pandemic in the sub-Sahara African r...

  9. Broadly Immunogenic HLA Class I Supertype-Restricted Elite CTL Epitopes Recognized in a Diverse Population Infected with Different HIV-1 Subtypes

    DEFF Research Database (Denmark)

    Pérez, Carina L; Larsen, Mette Voldby; Gustafsson, Rasmus

    2008-01-01

    The genetic variations of the HIV-1 virus and its human host constitute major obstacles for obtaining potent HIV-1-specific CTL responses in individuals of diverse ethnic backgrounds infected with different HIV-1 variants. In this study, we developed and used a novel algorithm to select 184......, not previously described in the HIV-1 immunology database. In addition, we identified 21 "elite" epitopes that induced CTL responses in at least 4 of the 31 patients. A majority (27 of 31) of the study population recognized one or more of these highly immunogenic epitopes. We also found a limited set of 9...

  10. A Population of planetary systems characterized by short-period, Earth-sized planets

    Science.gov (United States)

    Steffen, Jason H.; Coughlin, Jeffrey L.

    2016-01-01

    We analyze data from the Quarter 1–17 Data Release 24 (Q1–Q17 DR24) planet candidate catalog from NASA’s Kepler mission, specifically comparing systems with single transiting planets to systems with multiple transiting planets, and identify a population of exoplanets with a necessarily distinct system architecture. Such an architecture likely indicates a different branch in their evolutionary past relative to the typical Kepler system. The key feature of these planetary systems is an isolated, Earth-sized planet with a roughly 1-d orbital period. We estimate that at least 24 of the 144 systems we examined (≳17%) are members of this population. Accounting for detection efficiency, such planetary systems occur with a frequency similar to the hot Jupiters. PMID:27790984

  11. A Population of planetary systems characterized by short-period, Earth-sized planets.

    Science.gov (United States)

    Steffen, Jason H; Coughlin, Jeffrey L

    2016-10-25

    We analyze data from the Quarter 1-17 Data Release 24 (Q1-Q17 DR24) planet candidate catalog from NASA's Kepler mission, specifically comparing systems with single transiting planets to systems with multiple transiting planets, and identify a population of exoplanets with a necessarily distinct system architecture. Such an architecture likely indicates a different branch in their evolutionary past relative to the typical Kepler system. The key feature of these planetary systems is an isolated, Earth-sized planet with a roughly 1-d orbital period. We estimate that at least 24 of the 144 systems we examined ([Formula: see text]17%) are members of this population. Accounting for detection efficiency, such planetary systems occur with a frequency similar to the hot Jupiters.

  12. Effects of social organization, trap arrangement and density, sampling scale, and population density on bias in population size estimation using some common mark-recapture estimators.

    Directory of Open Access Journals (Sweden)

    Manan Gupta

    Full Text Available Mark-recapture estimators are commonly used for population size estimation, and typically yield unbiased estimates for most solitary species with low to moderate home range sizes. However, these methods assume independence of captures among individuals, an assumption that is clearly violated in social species that show fission-fusion dynamics, such as the Asian elephant. In the specific case of Asian elephants, doubts have been raised about the accuracy of population size estimates. More importantly, the potential problem for the use of mark-recapture methods posed by social organization in general has not been systematically addressed. We developed an individual-based simulation framework to systematically examine the potential effects of type of social organization, as well as other factors such as trap density and arrangement, spatial scale of sampling, and population density, on bias in population sizes estimated by POPAN, Robust Design, and Robust Design with detection heterogeneity. In the present study, we ran simulations with biological, demographic and ecological parameters relevant to Asian elephant populations, but the simulation framework is easily extended to address questions relevant to other social species. We collected capture history data from the simulations, and used those data to test for bias in population size estimation. Social organization significantly affected bias in most analyses, but the effect sizes were variable, depending on other factors. Social organization tended to introduce large bias when trap arrangement was uniform and sampling effort was low. POPAN clearly outperformed the two Robust Design models we tested, yielding close to zero bias if traps were arranged at random in the study area, and when population density and trap density were not too low. Social organization did not have a major effect on bias for these parameter combinations at which POPAN gave more or less unbiased population size estimates

  13. The Driving Forces of Cultural Complexity : Neanderthals, Modern Humans, and the Question of Population Size.

    Science.gov (United States)

    Fogarty, Laurel; Wakano, Joe Yuichiro; Feldman, Marcus W; Aoki, Kenichi

    2017-03-01

    The forces driving cultural accumulation in human populations, both modern and ancient, are hotly debated. Did genetic, demographic, or cognitive features of behaviorally modern humans (as opposed to, say, early modern humans or Neanderthals) allow culture to accumulate to its current, unprecedented levels of complexity? Theoretical explanations for patterns of accumulation often invoke demographic factors such as population size or density, whereas statistical analyses of variation in cultural complexity often point to the importance of environmental factors such as food stability, in determining cultural complexity. Here we use both an analytical model and an agent-based simulation model to show that a full understanding of the emergence of behavioral modernity, and the cultural evolution that has followed, depends on understanding and untangling the complex relationships among culture, genetically determined cognitive ability, and demographic history. For example, we show that a small but growing population could have a different number of cultural traits from a shrinking population with the same absolute number of individuals in some circumstances.

  14. Impact of Non-HIV and HIV Risk Factors on Survival in HIV-Infected Patients on HAART: A Population-Based Nationwide Cohort Study

    DEFF Research Database (Denmark)

    Obel, Niels; Omland, Lars Haukali; Kronborg, Gitte

    2011-01-01

    We determined the impact of three factors on mortality in HIV-infected patients who had been on highly active antiretroviral therapy (HAART) for at least one year: (1) insufficient response to (HAART) and presence of AIDS-defining diseases, (2) comorbidity, and (3) drug and alcohol abuse...

  15. Usage of purchased self-tests for HIV and sexually transmitted infections in Amsterdam, the Netherlands: results of population-based and serial cross-sectional studies among the general population and sexual risk groups

    NARCIS (Netherlands)

    Bil, Janneke P.; Prins, Maria; Stolte, Ineke G.; Dijkshoorn, Henriëtte; Heijman, Titia; Snijder, Marieke B.; Davidovich, Udi; Zuure, Freke R.

    2017-01-01

    Objectives There are limited data on the usage of commercially bought self-tests for HIV and other sexually transmitted infections (STIs). Therefore, we studied HIV/STI self-test usage and its determinants among the general population and sexual risk groups between 2007 and 2015 in Amsterdam, the

  16. Mental Health Disorders and Publicly Funded Service Use by HIV Positive Individuals: A Population-Based Cross-Sectional Study in Ontario, Canada.

    Science.gov (United States)

    Durbin, Anna; Brown, Hilary K; Antoniou, Tony; Sirotich, Frank; Bansal, Symron; Heifetz, Marina; Roesslein, Kay; Lunsky, Yona

    2017-12-01

    We compared use of community and hospital-based mental health and addiction (MH&A) services by adults with and without HIV. This population-based study examined the probability and intensity of MH&A service use by individuals with (n = 5095) and without HIV (n = 2,753,091) in Ontario, Canada between 2013 and 2014. Adults with HIV were more likely than HIV-negative adults to use MH&A primary and psychiatric care, and to have MH&A emergency department visits and hospital admissions; they also used more of each service. Use of MH&A hospital services was particularly high for persons in the HIV group compared to the no HIV group.

  17. Founder representation and effective population size in old versus young breeds-genetic diversity of Finnish and Nordic Spitz.

    Science.gov (United States)

    Kumpulainen, M; Anderson, H; Svevar, T; Kangasvuo, I; Donner, J; Pohjoismäki, J

    2017-10-01

    Finnish Spitz is 130-year-old breed and has been highly popular in Finland throughout its history. Nordic Spitz is very similar to Finnish Spitz by origin and use, but is a relatively recent breed with much smaller population size. To see how breed age and breeding history have influenced the current population, we performed comprehensive population genetic analysis using pedigree data of 28,119 Finnish and 9,009 Nordic Spitzes combined with genomewide single nucleotide polymorphism (SNP) data from 135 Finnish and 110 Nordic Spitzes. We found that the Finnish Spitz has undergone repeated male bottlenecks resulting in dramatic loss of genetic diversity, reflected by 20 effective founders (f a ) and mean heterozygosity (Hz) of 0.313. The realized effective population size in the breed based on pedigree analysis (N¯ec) is 168, whereas the genetic effective population size (N eg ) computed the decay of linkage disequilibrium (r 2 ) is only 57 individuals. Nordic Spitz, although once been near extinction, has not been exposed to similar repeated bottlenecks than Finnish Spitz and had f a of 27 individuals. However, due to the smaller total population size, the breed has also smaller effective population size than Finnish Spitz (N¯ec = 98 and N eg  = 49). Interestingly, the r 2 data show that the effective population size has contracted dramatically since the establishment of the breed, emphasizing the role of breed standards as constrains for the breeding population. Despite the small population size, Nordic Spitz still maintains SNP heterozygosity levels similar to mixed breed dogs (mean Hz = 0.409). Our study demonstrates that although pedigree analyses cannot provide estimates of the present diversity within a breed, the effective population sizes inferred from them correlate with the genotyping results. The genetic relationships of the northern Spitz breeds and the benefits of the open breed registry are discussed. © 2017 Blackwell Verlag GmbH.

  18. Psychosocial determinants of HIV testing across stages of change in Spanish population: a cross-sectional national survey

    Directory of Open Access Journals (Sweden)

    Maria Jose Fuster-RuizdeApodaca

    2017-03-01

    Full Text Available Abstract Background The goal of this research is to study the psychosocial determinants of HIV-testing as a function of the decision or change stage concerning this health behavior. The determinants considered in the major ongoing health models and the stages contemplated in the Precaution Adoption Process Model are analysed. Methods A cross-sectional survey was administered to 1,554 people over 16 years of age living in Spain by a computer-assisted telephone interview (CATI. The sample design was randomised, with quotas of sex and age. The survey measured various psychosocial determinants of health behaviors considered in the main cognitive theories, the interviewees' stage of change concerning HIV-testing (lack of awareness, decision not to act, decision to act, action, maintenance, and abandonment, and the signal for the action of getting tested or the perceived barriers to being tested. Results Approximately two thirds of the population had not ever had the HIV test. The predominant stage was lack of awareness. The most frequently perceived barriers to testing were related to the health system and to the stigma. We also found that the psychosocial determinants studied differed depending on the respondents' stage of change. Perception of risk, perceived self-efficacy, proximity to people who had been tested, perceived benefits of knowing the diagnosis, and a positive instrumental and emotional attitude were positively associated with the decision and maintenance of testing behavior. However, unrealistic underestimation of the risk of HIV infection, stereotypes about the infection, and the perceived severity of HIV were associated with the decision not to be tested. Conclusions There are various sociocognitive and motivational profiles depending on people’s decision stage concerning HIV-testing. Knowing this profile may allow us to design interventions to influence the psychosocial determinants that characterise each stage of change.

  19. The Genealogical Population Dynamics of HIV-1 in a Large Transmission Chain: Bridging within and among Host Evolutionary Rates

    Science.gov (United States)

    Vrancken, Bram; Rambaut, Andrew; Suchard, Marc A.; Drummond, Alexei; Baele, Guy; Derdelinckx, Inge; Van Wijngaerden, Eric; Vandamme, Anne-Mieke; Van Laethem, Kristel; Lemey, Philippe

    2014-01-01

    Transmission lies at the interface of human immunodeficiency virus type 1 (HIV-1) evolution within and among hosts and separates distinct selective pressures that impose differences in both the mode of diversification and the tempo of evolution. In the absence of comprehensive direct comparative analyses of the evolutionary processes at different biological scales, our understanding of how fast within-host HIV-1 evolutionary rates translate to lower rates at the between host level remains incomplete. Here, we address this by analyzing pol and env data from a large HIV-1 subtype C transmission chain for which both the timing and the direction is known for most transmission events. To this purpose, we develop a new transmission model in a Bayesian genealogical inference framework and demonstrate how to constrain the viral evolutionary history to be compatible with the transmission history while simultaneously inferring the within-host evolutionary and population dynamics. We show that accommodating a transmission bottleneck affords the best fit our data, but the sparse within-host HIV-1 sampling prevents accurate quantification of the concomitant loss in genetic diversity. We draw inference under the transmission model to estimate HIV-1 evolutionary rates among epidemiologically-related patients and demonstrate that they lie in between fast intra-host rates and lower rates among epidemiologically unrelated individuals infected with HIV subtype C. Using a new molecular clock approach, we quantify and find support for a lower evolutionary rate along branches that accommodate a transmission event or branches that represent the entire backbone of transmitted lineages in our transmission history. Finally, we recover the rate differences at the different biological scales for both synonymous and non-synonymous substitution rates, which is only compatible with the ‘store and retrieve’ hypothesis positing that viruses stored early in latently infected cells

  20. Psychosocial determinants of HIV testing across stages of change in Spanish population: a cross-sectional national survey.

    Science.gov (United States)

    Fuster-RuizdeApodaca, Maria Jose; Laguia, Ana; Molero, Fernando; Toledo, Javier; Arrillaga, Arantxa; Jaen, Angeles

    2017-03-07

    The goal of this research is to study the psychosocial determinants of HIV-testing as a function of the decision or change stage concerning this health behavior. The determinants considered in the major ongoing health models and the stages contemplated in the Precaution Adoption Process Model are analysed. A cross-sectional survey was administered to 1,554 people over 16 years of age living in Spain by a computer-assisted telephone interview (CATI). The sample design was randomised, with quotas of sex and age. The survey measured various psychosocial determinants of health behaviors considered in the main cognitive theories, the interviewees' stage of change concerning HIV-testing (lack of awareness, decision not to act, decision to act, action, maintenance, and abandonment), and the signal for the action of getting tested or the perceived barriers to being tested. Approximately two thirds of the population had not ever had the HIV test. The predominant stage was lack of awareness. The most frequently perceived barriers to testing were related to the health system and to the stigma. We also found that the psychosocial determinants studied differed depending on the respondents' stage of change. Perception of risk, perceived self-efficacy, proximity to people who had been tested, perceived benefits of knowing the diagnosis, and a positive instrumental and emotional attitude were positively associated with the decision and maintenance of testing behavior. However, unrealistic underestimation of the risk of HIV infection, stereotypes about the infection, and the perceived severity of HIV were associated with the decision not to be tested. There are various sociocognitive and motivational profiles depending on people's decision stage concerning HIV-testing. Knowing this profile may allow us to design interventions to influence the psychosocial determinants that characterise each stage of change.

  1. Microhabitat use, population densities, and size distributions of sulfur cave-dwelling Poecilia mexicana.

    Science.gov (United States)

    Jourdan, Jonas; Bierbach, David; Riesch, Rüdiger; Schießl, Angela; Wigh, Adriana; Arias-Rodriguez, Lenin; Indy, Jeane Rimber; Klaus, Sebastian; Zimmer, Claudia; Plath, Martin

    2014-01-01

    The Cueva del Azufre in Tabasco, Mexico, is a nutrient-rich cave and its inhabitants need to cope with high levels of dissolved hydrogen sulfide and extreme hypoxia. One of the successful colonizers of this cave is the poeciliid fish Poecilia mexicana, which has received considerable attention as a model organism to examine evolutionary adaptations to extreme environmental conditions. Nonetheless, basic ecological data on the endemic cave molly population are still missing; here we aim to provide data on population densities, size class compositions and use of different microhabitats. We found high overall densities in the cave and highest densities at the middle part of the cave with more than 200 individuals per square meter. These sites have lower H2S concentrations compared to the inner parts where most large sulfide sources are located, but they are annually exposed to a religious harvesting ceremony of local Zoque people called La Pesca. We found a marked shift in size/age compositions towards an overabundance of smaller, juvenile fish at those sites. We discuss these findings in relation to several environmental gradients within the cave (i.e., differences in toxicity and lighting conditions), but we also tentatively argue that the annual fish harvest during a religious ceremony (La Pesca) locally diminishes competition (and possibly, cannibalism by large adults), which is followed by a phase of overcompensation of fish densities.

  2. Family reintegration of children and adolescents in foster care in Brazilian municipalities with different population sizes.

    Science.gov (United States)

    Iannelli, Andrea M; Assis, Simone Gonçalves; Pinto, Liana Wernersbach; Pinto, Liana Wenersbach

    2015-01-01

    The scope of this article is to present and analyze data from Brazilian foster care services for children / adolescents from the perspective of family reintegration. It also seeks to support the implementation of public policies in order to provide effective reintegration in accordance with the differing local contexts. It uses data from 1,157 municipalities that have foster care services. The methodology takes into account the data collection of 2,624 Brazilian centers and 36,929 children and adolescents in care. The growing number of children/adolescents in care is in line with the increase in population size: 8.4 per small city; 60 per large city and 602.4 per metropolis. With respect to care residence in a different municipality there are varying indices: 12.4% in metropolises and 33.6% in small cities, revealing the absence of centers close to family units in the smaller communities. Regarding the activities promoted together with families, it was seen that there are still units that do not perform any activities, which runs contrary to Brazilian law. It is clear that policies for the child/adolescent in foster care centers need to consider the capacity of the municipality in accordance with population size to implement support actions for families to assist in family reintegration.

  3. Family reintegration of children and adolescents in foster care in Brazilian municipalities with different population sizes

    Directory of Open Access Journals (Sweden)

    Andrea M. Iannelli

    2015-01-01

    Full Text Available The scope of this article is to present and analyze data from Brazilian foster care services for children / adolescents from the perspective of family reintegration. It also seeks to support the implementation of public policies in order to provide effective reintegration in accordance with the differing local contexts. It uses data from 1,157 municipalities that have foster care services. The methodology takes into account the data collection of 2,624 Brazilian centers and 36,929 children and adolescents in care. The growing number of children/adolescents in care is in line with the increase in population size: 8.4 per small city; 60 per large city and 602.4 per metropolis. With respect to care residence in a different municipality there are varying indices: 12.4% in metropolises and 33.6% in small cities, revealing the absence of centers close to family units in the smaller communities. Regarding the activities promoted together with families, it was seen that there are still units that do not perform any activities, which runs contrary to Brazilian law. It is clear that policies for the child/adolescent in foster care centers need to consider the capacity of the municipality in accordance with population size to implement support actions for families to assist in family reintegration.

  4. Estimation of population pharmacokinetic parameters of saquinavir in HIV patients with the MONOLIX software.

    Science.gov (United States)

    Lavielle, Marc; Mentré, France

    2007-04-01

    In nonlinear mixed-effects models, estimation methods based on a linearization of the likelihood are widely used although they have several methodological drawbacks. Kuhn and Lavielle (Comput. Statist. Data Anal. 49:1020-1038 (2005)) developed an estimation method which combines the SAEM (Stochastic Approximation EM) algorithm, with a MCMC (Markov Chain Monte Carlo) procedure for maximum likelihood estimation in nonlinear mixed-effects models without linearization. This method is implemented in the Matlab software MONOLIX which is available at http://www.math.u-psud.fr/~lavielle/monolix/logiciels. In this paper we apply MONOLIX to the analysis of the pharmacokinetics of saquinavir, a protease inhibitor, from concentrations measured after single dose administration in 100 HIV patients, some with advance disease. We also illustrate how to use MONOLIX to build the covariate model using the Bayesian Information Criterion. Saquinavir oral clearance (CL/F) was estimated to be 1.26 L/h and to increase with body mass index, the inter-patient variability for CL/F being 120%. Several methodological developments are ongoing to extend SAEM which is a very promising estimation method for population pharmacockinetic/pharmacodynamic analyses.

  5. Gradual adaptation of HIV to human host populations: good or bad news?

    Science.gov (United States)

    Brander, Christian; Walker, Bruce D

    2003-11-01

    The continuous evolution and adaptation of HIV to its host has produced extensive global viral diversity. Understanding the kinetics and directions of this continuing adaptation and its impact on viral fitness, immunogenicity and pathogenicity will be crucial to the successful design of effective HIV vaccines. Here we discuss some potential scenarios of viral and host coevolution.

  6. The Intersectionality of Stigmas among Key Populations of Older Adults Affected by HIV: a Thematic Analysis.

    Science.gov (United States)

    Johnson Shen, Megan; Freeman, Ryann; Karpiak, Stephen; Brennan-Ing, Mark; Seidel, Liz; Siegler, Eugenia L

    2018-03-26

    The present study examined the intersectionality of stigma across varying groups of older persons living with HIV (PWH). Four focus groups of older PWH (gay/bisexual men, heterosexual men, heterosexual and bisexualwomen, and Spanish-speaking) were audio-recorded and transcribed. Inductive thematic text analysis was used to identify qualitative themes. Five major themes emerged from the data: 1) disclosure of HIV status; 2) types of stigma experienced; 3) discrimination experienced; 4) other outcomes associated with experiencing stigma; and 5) influence of aging on social isolation experienced due to stigma. Findings indicate women did not suffer from the intersection of stigmas. Other groups suffered from the intersection of stigma due to HIV status and age (gay/bisexual males); HIV status and perceived stigma of sexual orientation or drug use (heterosexual males); and HIV status and culture/ethnicity (Spanish-speaking). Results indicate that many at-risk groups, including heterosexual men, homosexual men, and Spanish-speaking individuals, experience an intersection of stigma between aging and their sexuality, HIV status, or real or perceived drug use. Results highlight the need for HIV support, especially social support, to address intersection of stigmas for unique groups of individuals disproportionately affected by HIV.

  7. Biomedical Risk, Psychosocial Influences, and Developmental Outcomes: Lessons from the Pediatric HIV Population in Africa

    Science.gov (United States)

    Serpell, Robert; Marfo, Kofi; Abubakar, Amina

    2014-01-01

    Sub-Saharan Africa is home to millions of HIV-affected children. These children are likely to experience multiple developmental delays. In this chapter, I present data highlighting compromised neurobehavioral, mental health, and scholastic outcomes for children affected by HIV. Furthermore, I discuss biomedical factors (e.g., disease severity and…

  8. A Neglected Population: Drug-Using Women and Women's Methods of HIV/STI Prevention

    Science.gov (United States)

    Gollub, Erica L.

    2008-01-01

    Women drug users are at extremely high risk of HIV and sexually transmitted infections (STIs) from sexual transmission, but remain seriously neglected in intervention research promoting women-initiated methods of HIV/STI prevention. Sparse available data indicate a high interest and enthusiasm for women-initiated methods among these women.…

  9. Biomedical risk, psychosocial influences, and developmental outcomes : Lessons from the pediatric HIV population in Africa

    NARCIS (Netherlands)

    Ali, A.A.

    2014-01-01

    Sub-Saharan Africa is home to millions of HIV-affected children. These children are likely to experience multiple developmental delays. In this chapter, I present data highlighting compromised neurobehavioral, mental health, and scholastic outcomes for children affected by HIV. Furthermore, I

  10. HIV-1 Disease Progression and Survival in an Adult Population in Zimbabwe

    DEFF Research Database (Denmark)

    Zinyama-Gutsire, Rutendo B L; Chasela, Charles; Kallestrup, Per

    2015-01-01

    HIV infection remains a major global health burden since its discovery in 1983. Sub-Saharan Africa is the region hardest hit by the HIV/AIDS pandemic where 63% of the 33 million infected people live. While there is marked person-to-person variability in susceptibility, progression, and survival...

  11. Parameters in the estimation of the most suitable F2 population size in conventional maize (Zea mays L. breeding programs

    Directory of Open Access Journals (Sweden)

    Delić Nenad

    2010-01-01

    Full Text Available The objective of the present study was to observe differences among four sizes of the F2 populations (100, 200, 300 and 500 plants on the basis of test-crosses for grain yield according to the average values of the populations, genetic and phenotypic variances, genotypic and phenotypic coefficients of variations and broad-sense heritability. The values of genetic variance did not significantly differ over population sizes according to all possible comparisons, including the comparison of values obtained for the phenotypic variance. Furthermore, the values of broadsense heritability (67.8%-69% did not significantly vary over different F2 population sizes. Genetic variability of the observed progenies, as a principal prerequisite of successful selection, was at the satisfactory level in all population sizes.

  12. Body size and obesity patterns in Caboclo populations from Pará, Amazonia, Brazil.

    Science.gov (United States)

    Silva, Hilton; Padez, Cristina

    2010-04-01

    In many developing countries overweight, obesity and obesity-related morbidity are becoming a problem of increasing public health importance. The purpose of this study was to investigate differences in body size and body composition with age in adults of the Caboclo populations from the Brazilian Amazon as well as to examine the prevalence of overweight and obesity in adults aged 20-75 years, taking into account recent trends for the whole country. Caboclo are genetically and culturally admixed rural peasant groups that live along the Amazon River and its tributaries in Brazil, and there are few previous studies of their health and lifestyle. A total of 304 subjects (149 males and 155 females) from two socioecologically different areas were studied. Height, weight and skinfolds (tricipital, subscapular and suprailiac) were measured; international intervals (WHO) for overweight and obesity were used. Women showed significantly lower values than men for height, weight, upper arm circumference and fat-free mass and higher values for triceps, subscapular and suprailiac skinfolds and body fat (%). In the overall sample combined overweight and obesity was 47.8% in men and 50.8% in women. When compared to recent values published for the Northern region and for the whole of Brazil, 20.5% of Caboclo women aged 20-75 years were obese, which is higher than all other populations, including other rural samples. Caboclo men showed the highest rates of obesity (9.1%) and overweight (39.1%) of any rural population from the country, including Northern Brazil. The results suggest an effect of increased Western lifestyle influence on the body composition of these Caboclo populations. Considering that these are rural populations with limited access to education and health care, the high prevalence of overweight and obesity associated with low socio-economic status makes them a vulnerable group that deserves a higher level of attention by the country's public health authorities.

  13. Whitebark pine, population density, and home-range size of grizzly bears in the greater yellowstone ecosystem.

    Science.gov (United States)

    Bjornlie, Daniel D; Van Manen, Frank T; Ebinger, Michael R; Haroldson, Mark A; Thompson, Daniel J; Costello, Cecily M

    2014-01-01

    Changes in life history traits of species can be an important indicator of potential factors influencing populations. For grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE), recent decline of whitebark pine (WBP; Pinus albicaulis), an important fall food resource, has been paired with a slowing of population growth following two decades of robust population increase. These observations have raised questions whether resource decline or density-dependent processes may be associated with changes in population growth. Distinguishing these effects based on changes in demographic rates can be difficult. However, unlike the parallel demographic responses expected from both decreasing food availability and increasing population density, we hypothesized opposing behavioral responses of grizzly bears with regard to changes in home-range size. We used the dynamic changes in food resources and population density of grizzly bears as a natural experiment to examine hypotheses regarding these potentially competing influences on grizzly bear home-range size. We found that home-range size did not increase during the period of whitebark pine decline and was not related to proportion of whitebark pine in home ranges. However, female home-range size was negatively associated with an index of population density. Our data indicate that home-range size of grizzly bears in the GYE is not associated with availability of WBP, and, for female grizzly bears, increasing population density may constrain home-range size.

  14. Whitebark pine, population density, and home-range size of grizzly bears in the greater yellowstone ecosystem.

    Directory of Open Access Journals (Sweden)

    Daniel D Bjornlie

    Full Text Available Changes in life history traits of species can be an important indicator of potential factors influencing populations. For grizzly bears (Ursus arctos in the Greater Yellowstone Ecosystem (GYE, recent decline of whitebark pine (WBP; Pinus albicaulis, an important fall food resource, has been paired with a slowing of population growth following two decades of robust population increase. These observations have raised questions whether resource decline or density-dependent processes may be associated with changes in population growth. Distinguishing these effects based on changes in demographic rates can be difficult. However, unlike the parallel demographic responses expected from both decreasing food availability and increasing population density, we hypothesized opposing behavioral responses of grizzly bears with regard to changes in home-range size. We used the dynamic changes in food resources and population density of grizzly bears as a natural experiment to examine hypotheses regarding these potentially competing influences on grizzly bear home-range size. We found that home-range size did not increase during the period of whitebark pine decline and was not related to proportion of whitebark pine in home ranges. However, female home-range size was negatively associated with an index of population density. Our data indicate that home-range size of grizzly bears in the GYE is not associated with availability of WBP, and, for female grizzly bears, increasing population density may constrain home-range size.

  15. Whitebark pine, population density, and home-range size of grizzly bears in the greater Yellowstone ecosystem

    Science.gov (United States)

    Bjornlie, Daniel D.; van Manen, Frank T.; Ebinger, Michael R.; Haroldson, Mark A.; Thompson, Daniel J.; Costello, Cecily M.

    2014-01-01

    Changes in life history traits of species can be an important indicator of potential factors influencing populations. For grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE), recent decline of whitebark pine (WBP; Pinus albicaulis), an important fall food resource, has been paired with a slowing of population growth following two decades of robust population increase. These observations have raised questions whether resource decline or density-dependent processes may be associated with changes in population growth. Distinguishing these effects based on changes in demographic rates can be difficult. However, unlike the parallel demographic responses expected from both decreasing food availability and increasing population density, we hypothesized opposing behavioral responses of grizzly bears with regard to changes in home-range size. We used the dynamic changes in food resources and population density of grizzly bears as a natural experiment to examine hypotheses regarding these potentially competing influences on grizzly bear home-range size. We found that home-range size did not increase during the period of whitebark pine decline and was not related to proportion of whitebark pine in home ranges. However, female home-range size was negatively associated with an index of population density. Our data indicate that home-range size of grizzly bears in the GYE is not associated with availability of WBP, and, for female grizzly bears, increasing population density may constrain home-range size.

  16. Assessment of crown angulations, crown inclinations, and tooth size discrepancies in a South Indian population

    Directory of Open Access Journals (Sweden)

    Geeta Maruti Doodamani

    2011-01-01

    Full Text Available Aims and Objective: The aim of this study was to assess crown angulations, crown inclinations, and tooth size discrepancy in a sample population from Davangere, South India. Materials and Methods: One hundred adults (50 male and 50 female of age 18-30 years, with Angle′s class I ideal occlusion and balanced profiles, were selected for the study. Study models were prepared and crown angulations and crown inclinations were measured using a customized protractor device. Bolton′s analysis was used to measure the tooth size discrepancies. Results: Maxillary and mandibular teeth had less crown angulations. Maxillary and mandibular incisors and maxillary molars showed increased crown inclinations, whereas mandibular molars and premolars had less crown inclinations than the original Andrews sample. The mean maxillary and mandibular tooth size ratios, overall and anterior, were similar to Bolton′s ratios. Conclusions: The finding of this study indicates that there are possible racial and ethnic factors contributing to variations in crown angulations and crown inclinations.

  17. Age related changes in size of thyroid follicle in north Indian population: A histologic study

    Directory of Open Access Journals (Sweden)

    Preeti Malik

    2016-05-01

    Full Text Available Due to increasing number of cases of thyroid gland disorders nowadays, there are rising trends of thyroid gland surgeries and interventions which requires comprehensive data regarding the gland. This study was done to find out the changes in the size of the thyroid follicle in different age groups. The age groups were Group A - upto 20 years, Group B – 21-50 years and Group C – above 50 years. The study was conducted on 60 human thyroid glands in the Department of Anatomy in collaboration with Department of Pathology, Pt. B. D. Sharma Post Graduate Institute of Medical Sciences, Rohtak in North Indian population. The diameter of the thyroid follicle was measured by Image Analyzer. The study revealed that the mean size of the thyroid follicle was found to be in Group A - 56.38±14.12 µm, Group B - 130.08±30.67 µm and Group C - 96.05±12.86 µm. The study concluded that the mean size of the thyroid follicle was found to be higher in Group B (21-50 years followed by Group C (above 50 years followed by Group A (below 20 years.

  18. Measuring replication competent HIV-1: advances and challenges in defining the latent reservoir

    OpenAIRE

    Wang, Zheng; Simonetti, Francesco R.; Siliciano, Robert F.; Laird, Gregory M.

    2018-01-01

    Antiretroviral therapy cannot cure HIV-1 infection due to the persistence of a small number of latently infected cells harboring replication-competent proviruses. Measuring persistent HIV-1 is challenging, as it consists of a mosaic population of defective and intact proviruses that can shift from a state of latency to active HIV-1 transcription. Due to this complexity, most of the current assays detect multiple categories of persistent HIV-1, leading to an overestimate of the true size of th...

  19. Tiller size/population density compensation in grazed Coastcross bermudagrass swards

    Directory of Open Access Journals (Sweden)

    Sbrissia André Fischer

    2001-01-01

    Full Text Available Several compensatory mechanisms in pastures do not allow optimisation of responses from the processes of herbage production and utilisation. Compensation due to tiller size/density relationships is one of these mechanisms. This experiment evaluated this process for Coastcross bermudagrass and compared the responses to those reported for temperate forages. Treatments were "steady state" sward surface heights of 5, 10, 15, and 20 cm that were maintained from August, 1998, through July, 1999 by sheep grazing. The experimental design was a randomised complete block, replicated four times. Pasture responses were evaluated on four separate dates (15/12/1998, 25/01/1999, 07/04/1999 and 04/07/1999 with respect to: tiller population density, tiller weight, leaf mass and leaf area per tiller and herbage mass (biomass. Tiller volume, leaf area index (LAI, tiller leaf:stem ratio and tiller leaf area:volume ratio (R were calculated. Simple regression analyses between tiller population density and tiller weight were also performed. Coastcross swards showed a tiller size/density compensation mechanism where high tiller population densities were associated with small tillers and vice-versa; except on the last evaluation. However, regression analysis revealed linear coefficients of -3.83 to -2.05, which are lower than the theoretical expectation of -3/2. The lower R values observed, when compared to those reported for perennial ryegrass, suggest that Coastcross swards optimised their LAI via clonal integration among tillers in contrast with tillers of cool-season grasses that respond more as individuals. However, this hypothesis has yet to be experimentally verified.

  20. Prediction of Un-erupted Canine and Premolar Tooth Size in Mixed Dentition among Bangladeshi Population.

    Science.gov (United States)

    Chokrobrty, R; Rafique, T; Ghosh, R; Biswas, A K; Sajedeen, M; Hassan, G S

    2017-10-01

    Accurate prediction of the space available to accommodate the size of the un-erupted canines and premolars plays an important role in mixed dentition in Orthodontics. This Descriptive cross sectional study was carried out in the Department of Orthodontics of Bangabandhu Sheikh Mujib Medical University from July 2014 to June 2015. Dental study models of 140 patients were taken as sample. The sample was consisted of 54 Bangladeshi males and 86 females aged between 12 to 17 years and without any previous orthodontic treatment fully erupted permanent teeth and with no dental anomalies were recruited. The study was done by measuring the mesio-distal dimensions of teeth over the dental cast. A pre-structured data collection form which includes the particulars of the patient and data was filled. All patients were having a serial number to maintain their confidentiality. The study protocol was approved by "Institutional Review Board" of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh. Un-paired t test were used to examine differences between genders, correlation coefficients and linear regression equations were used to carry out the analysis. Descriptive statistics including means, standard deviations, and minimum-maximum values were calculated. Unpaired sample 't' tests were carried out to compare tooth size between the sexes. Logistic regression for development of new prediction formula on the basis of study sample of our population. Pearson correlation coefficient test for found the correlation between mandibular incisors and mandibular and maxillary canine and premolars in each quadrant. The difference between the present study with that of Moyers and Tanaka and Johnston were statistically significant (p<0.001). The values from Moyers and Tanaka and Johnston methods exceed while comparing to Bangladeshi population. Therefore, Moyers and Tanaka and Johnston method of prediction are not applicable for our population.

  1. All-cause mortality in treated HIV-infected adults with CD4 ≥500/mm3 compared with the general population

    DEFF Research Database (Denmark)

    Lewden, Charlotte; Bouteloup, Vincent; De Wit, Stéphane

    2012-01-01

    Using data from a large European collaborative study, we aimed to identify the circumstances in which treated HIV-infected individuals will experience similar mortality rates to those of the general population.......Using data from a large European collaborative study, we aimed to identify the circumstances in which treated HIV-infected individuals will experience similar mortality rates to those of the general population....

  2. A Proposed Approach for Joint Modeling of the Longitudinal and Time-To-Event Data in Heterogeneous Populations: An Application to HIV/AIDS's Disease.

    Science.gov (United States)

    Roustaei, Narges; Ayatollahi, Seyyed Mohammad Taghi; Zare, Najaf

    2018-01-01

    In recent years, the joint models have been widely used for modeling the longitudinal and time-to-event data simultaneously. In this study, we proposed an approach (PA) to study the longitudinal and survival outcomes simultaneously in heterogeneous populations. PA relaxes the assumption of conditional independence (CI). We also compared PA with joint latent class model (JLCM) and separate approach (SA) for various sample sizes (150, 300, and 600) and different association parameters (0, 0.2, and 0.5). The average bias of parameters estimation (AB-PE), average SE of parameters estimation (ASE-PE), and coverage probability of the 95% confidence interval (CP) among the three approaches were compared. In most cases, when the sample sizes increased, AB-PE and ASE-PE decreased for the three approaches, and CP got closer to the nominal level of 0.95. When there was a considerable association, PA in comparison with SA and JLCM performed better in the sense that PA had the smallest AB-PE and ASE-PE for the longitudinal submodel among the three approaches for the small and moderate sample sizes. Moreover, JLCM was desirable for the none-association and the large sample size. Finally, the evaluated approaches were applied on a real HIV/AIDS dataset for validation, and the results were compared.

  3. A Proposed Approach for Joint Modeling of the Longitudinal and Time-To-Event Data in Heterogeneous Populations: An Application to HIV/AIDS’s Disease

    Directory of Open Access Journals (Sweden)

    Narges Roustaei

    2018-01-01

    Full Text Available In recent years, the joint models have been widely used for modeling the longitudinal and time-to-event data simultaneously. In this study, we proposed an approach (PA to study the longitudinal and survival outcomes simultaneously in heterogeneous populations. PA relaxes the assumption of conditional independence (CI. We also compared PA with joint latent class model (JLCM and separate approach (SA for various sample sizes (150, 300, and 600 and different association parameters (0, 0.2, and 0.5. The average bias of parameters estimation (AB-PE, average SE of parameters estimation (ASE-PE, and coverage probability of the 95% confidence interval (CP among the three approaches were compared. In most cases, when the sample sizes increased, AB-PE and ASE-PE decreased for the three approaches, and CP got closer to the nominal level of 0.95. When there was a considerable association, PA in comparison with SA and JLCM performed better in the sense that PA had the smallest AB-PE and ASE-PE for the longitudinal submodel among the three approaches for the small and moderate sample sizes. Moreover, JLCM was desirable for the none-association and the large sample size. Finally, the evaluated approaches were applied on a real HIV/AIDS dataset for validation, and the results were compared.

  4. The Hawkesbury-Nepean region: has the optimum population size been exceeded?

    Science.gov (United States)

    Jones, A; Pearson, B

    1995-01-01

    The Australian Federal Government has not included population size as an intersectoral component of the environmentally sustainable development process. The aim of this article is to show how water quality is a key indicator of environmental degradation and of declines in the quality of life. This study is an analysis of the environmental impacts of population on the Hawkesbury-Nepean River System and of the costs involved in change. Environmental degradation is viewed as the result of population size, per capita consumption, the quality of technology, and the organization of space and technology. The quantity and quality of freshwater systems are considered to be useful indicators of environmental degradation over large spatial areas because the impacts are associated with both land and water environments. The catchment area of this river system covers about 231,730 sq. km (68% bushland, 5% urban, 25% agricultural, and 0.1% industrial). About 45% of the land area is protected due to six dams, which provide 98% of water used in Sydney, Illawarra, and the Blue Mountains. Estimated population usage is 600,000-700,000 people. River flows are modified by dams, sewage discharges, water abstractions, and urban run-off from development. River use includes tourism, fishing, and recreation. The system suffers from severe eutrophication, bacterial contamination, toxic pollution, and hypoxia. The conclusion was reached after many years of concern that large-scale development should be deferred. However, housing plans continue for a 70% population increase by 2008. Sewage treatment improvements are costly. Alternatives are re-use of effluents ($2.5-3.5 billion for nonpotable use and $4-4.5 billion for potable use), diversion to the ocean ($3 billion), zero river discharge ($8400 per property for installation and $700 per annum maintenance), or inland disposal ($19 billion). Environmental protection efforts are also costly: $45 million worth of water for flushing away an algal

  5. The limits of weak selection and large population size in evolutionary game theory.

    Science.gov (United States)

    Sample, Christine; Allen, Benjamin

    2017-11-01

    Evolutionary game theory is a mathematical approach to studying how social behaviors evolve. In many recent works, evolutionary competition between strategies is modeled as a stochastic process in a finite population. In this context, two limits are both mathematically convenient and biologically relevant: weak selection and large population size. These limits can be combined in different ways, leading to potentially different results. We consider two orderings: the [Formula: see text] limit, in which weak selection is applied before the large population limit, and the [Formula: see text] limit, in which the order is reversed. Formal mathematical definitions of the [Formula: see text] and [Formula: see text] limits are provided. Applying these definitions to the Moran process of evolutionary game theory, we obtain asymptotic expressions for fixation probability and conditions for success in these limits. We find that the asymptotic expressions for fixation probability, and the conditions for a strategy to be favored over a neutral mutation, are different in the [Formula: see text] and [Formula: see text] limits. However, the ordering of limits does not affect the conditions for one strategy to be favored over another.

  6. Allee’s dynamics and bifurcation structures in von Bertalanffy’s population size functions

    Science.gov (United States)

    Leonel Rocha, J.; Taha, Abdel-Kaddous; Fournier-Prunaret, D.

    2018-03-01

    The interest and the relevance of the study of the population dynamics and the extinction phenomenon are our main motivation to investigate the induction of Allee Effect in von Bertalanffy’s population size functions. The adjustment or correction factor of rational type introduced allows us to analyze simultaneously strong and weak Allee’s functions and functions with no Allee effect, whose classification is dependent on the stability of the fixed point x = 0. This classification is founded on the concepts of strong and weak Allee’s effects to the population growth rates associated. The transition from strong Allee effect to no Allee effect, passing through the weak Allee effect, is verified with the evolution of the rarefaction critical density or Allee’s limit. The existence of cusp points on a fold bifurcation curve is related to this phenomenon of transition on Allee’s dynamics. Moreover, the “foliated” structure of the parameter plane considered is also explained, with respect to the evolution of the Allee limit. The bifurcation analysis is based on the configurations of fold and flip bifurcation curves. The chaotic semistability and the nonadmissibility bifurcation curves are proposed to this family of 1D maps, which allow us to define and characterize the corresponding Allee effect region.

  7. Is there a relationship between geographic distance and uptake of HIV testing services? A representative population-based study of Chinese adults in Guangzhou, China.

    Directory of Open Access Journals (Sweden)

    Wen Chen

    Full Text Available Achieving high coverage of HIV testing services is critical in many health systems, especially where HIV testing services remain centralized and inconvenient for many. As a result, planning the optimal spatial distribution of HIV testing sites is increasingly important. We aimed to assess the relationship between geographic distance and uptake of HIV testing services among the general population in Guangzhou, China. Utilizing spatial epidemiological methods and stratified household random sampling, we studied 666 adults aged 18-59. Computer-assisted interviews assessed self-reported HIV testing history. Spatial scan statistic assessed the clustering of participants who have ever been tested for HIV, and two-level logistic regression models assessed the association between uptake of HIV testing and the mean driving distance from the participant's residence to all HIV testing sites in the research sites. The percentage of participants who have ever been tested for HIV was 25.2% (168/666, 95%CI: 21.9%, 28.5%, and the majority (82.7% of participants tested for HIV in Centres for Disease Control and Prevention, public hospitals or STIs clinics. None reported using self-testing. Spatial clustering analyses found a hotspot included 48 participants who have ever been tested for HIV and 25.8 expected cases (Rate Ratio = 1.86, P = 0.002. Adjusted two-level logistic regression found an inverse relationship between geographic distance (kilometers and ever being tested for HIV (aOR = 0.90, 95%CI: 0.84, 0.96. Married or cohabiting participants (aOR = 2.14, 95%CI: 1.09, 4.20 and those with greater social support (aOR = 1.04, 95%CI: 1.01, 1.07 were more likely to be tested for HIV. Our findings underscore the importance of considering the geographical distribution of HIV testing sites to increase testing. In addition, expanding HIV testing coverage by introducing non-facility based HIV testing services and self-testing might be useful to achieve the goal that

  8. Changes in mortality rates and causes of death in a population-based cohort of persons living with and without HIV from 1996 to 2012.

    Science.gov (United States)

    Eyawo, Oghenowede; Franco-Villalobos, Conrado; Hull, Mark W; Nohpal, Adriana; Samji, Hasina; Sereda, Paul; Lima, Viviane D; Shoveller, Jeannie; Moore, David; Montaner, Julio S G; Hogg, Robert S

    2017-02-27

    Non-HIV/AIDS-related diseases are gaining prominence as important causes of morbidity and mortality among people living with HIV. The purpose of this study was to characterize and compare changes over time in mortality rates and causes of death among a population-based cohort of persons living with and without HIV in British Columbia (BC), Canada. We analysed data from the Comparative Outcomes And Service Utilization Trends (COAST) study; a retrospective population-based study created via linkage between the BC Centre for Excellence in HIV/AIDS and Population Data BC, and containing data for HIV-infected individuals and the general population of BC, respectively. Our analysis included all known HIV-infected adults (≥ 20 years) in BC and a random 10% sample of uninfected BC adults followed from 1996 to 2012. Deaths were identified through Population Data BC - which contains information on all registered deaths in BC (BC Vital Statistics Agency dataset) and classified into cause of death categories using International Classification of Diseases (ICD) 9/10 codes. Age-standardized mortality rates (ASMR) and mortality rate ratios were calculated. Trend test were performed. 3401 (25%), and 47,647 (9%) individuals died during the 5,620,150 person-years of follow-up among 13,729 HIV-infected and 510,313 uninfected individuals, respectively. All-cause and cause-specific mortality rates were consistently higher among HIV-infected compared to HIV-negative individuals, except for neurological disorders. All-cause ASMR decreased from 126.75 (95% CI: 84.92-168.57) per 1000 population in 1996 to 21.29 (95% CI: 17.79-24.79) in 2011-2012 (83% decline; p ASMR reductions were also observed for hepatic/liver disease and drug abuse/overdose deaths. ASMRs for neurological disorders increased significantly over time. Non-AIDS-defining cancers are currently the leading non-HIV/AIDS-related cause of death in both HIV-infected and uninfected individuals. Despite the significant

  9. Using risk-tracing snowball approach to increase HIV case detection among high-risk populations in Cambodia: an intervention study.

    Science.gov (United States)

    Chhim, Srean; Macom, John; Pav, Chettana; Nim, Nirada; Yun, Phearun; Seng, Sopheap; Chhim, Kolab; Tuot, Sovannary; Yi, Siyan

    2017-10-18

    Early HIV diagnosis and initiation onto antiretroviral therapy may prevent ongoing spread of HIV. Risk Tracing Snowball Approach (RTSA) has been shown to be effective in detecting new HIV cases in other settings. The main objective of this study is to evaluate the effectiveness of RTSA in increasing the rate of newly identified HIV cases among high-risk populations. Our second objective was to evaluate the effectiveness of RTSA, as compared to the walk-in group, in increasing the number of HIV tests and early case detection. This study was conducted from April 1 to September 30, 2016 at two NGO clinics in Phnom Penh, Cambodia. Respondent driven sampling method was adapted to develop RTSA to reach high-risk populations, including key populations and the general population who have social connections with key populations. Bivariate and multivariate logistic regression analyses were conducted. During the implementation period, 721 clients walked in for HIV testing (walk-in group), and all were invited to be seeds. Of the invited clients, 36.6% agreed to serve as seeds. Throughout the implementation, 6195 coupons were distributed to seeds or recruiters, and resulted in 1572 clients visiting the two clinics with coupons (RTSA group), for a coupon return rate of 25.3%. The rate of newly identified HIV cases among the RTSA group was significantly lower compared to that in walk-in group. However, the highest number of newly identified HIV cases was found during the implementation period, compared to both pre- and post-implementation period. Although statistically not significant, the mean CD4 count of newly identified HIV cases detected through RTSA was almost 200 cells/mm3 higher than that in the walk-in group. Although the rate of newly identified HIV cases among the RTSA group was lower than that in the walk-in group, the inclusion of RTSA in addition to the traditional walk-in method boosted new HIV case detection in the two participating clinics. A higher mean CD4

  10. Evaluating the effect of HIV prevention strategies on uptake of HIV counselling and testing among male most-at-risk-populations in Nigeria; a cross-sectional analysis.

    Science.gov (United States)

    Adebajo, Sylvia; Eluwa, George; Njab, Jean; Oginni, Ayo; Ukwuije, Francis; Ahonsi, Babatunde; Lorenc, Theo

    2015-12-01

    The aim of this study was to evaluate the effects of three strategies in increasing uptake of HIV counselling and testing (HCT) among male most-at-risk-population (M-MARPs) using programmatic data. HIV prevention strategies were evaluated in a cross-sectional analysis. Three HCT strategies were implemented between July 2009 and July 2012 among men who have sex with men (MSM) and people who inject drugs (PWIDs) in four states in Nigeria. The first strategy (S1), involved key opinion leaders (KOLs) who referred M-MARPs to health facilities for HCT. The second strategy (S2) involved KOLs referring M-MARPs to nearby mobile HCT teams while the third (S3) involved mobile M-MARPs peers conducting the HCT. χ(2) statistics were used to test for differences in the distribution of categorical variables across groups while logistic regression was used to measure the effect of the different strategies while controlling for confounding factors. A total of 1988, 14 726 and 14 895 M-MARPs were offered HCT through S1, S2 and S3 strategies, respectively. Overall, S3 (13%) identified the highest proportion of HIV-positive M-MARPs compared with S1 (9%) and S2 (3%), p≤0.001. Also S3 (13%) identified the highest proportion of new HIV diagnosis compared with S1 (8%) and S2 (3%), respectively, p≤0.001. When controlled for age, marital status and occupation, MSM reached via S3 were 9 times (AOR: 9.21; 95% CI 5.57 to 15.23) more likely to uptake HCT when compared with S1 while PWIDs were 21 times (AOR: 20.90; 95% CI 17.33 to 25.21) more likely to uptake to HCT compared with those reached via S1. Peer-led HCT delivered by S3 had the highest impact on the total number of M-MARPs reached and in identifying HIV-positive M-MARPs and new testers. Training M-MARPs peers to provide HCT is a high impact approach in delivering HCT to M-MARPs. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  11. Development of an In-House Multiplex Nested RT-PCR Method for Detecting Acute HIV-1 Infection in High Risk Populations.

    Science.gov (United States)

    Liu, Zhiying; Li, Wei; Xu, Meng; Sheng, Bo; Yang, Zixuan; Jiao, Yanmei; Zhang, Tong; Mou, Danlei; Chen, Dexi; Wu, Hao

    2015-01-01

    The detection of acute HIV infection (AHI) among high risk populations can help reduce secondary transmission of HIV. The nucleic acid testing (NAT) can shorten the test window period by up to 7-12 days. In this study, we describe an in-house NAT based on the multiplex nested RT-PCR method to detect the HIV RNA. We also evaluated it in a high risk cohort in Beijing. Four primer pairs were designed and evaluated for the detection of different HIV-1 subtypes in group M. Multiplex RT-PCR and nested PCR were performed. The sensitivity, specialty, primers compatibility among HIV subtypes were evaluated simultaneously. In an MSM cohort in Beijing during a 3-year period, a total of 11,808 blood samples that were negative by ELISA or indeterminate by Western blot were analyzed by this multiplex nested RT-PCR with pooling strategy. The multiplex nested RT-PCR was successfully applied for the detection of at least six HIV-1 subtypes. The sensitivity was 40 copies/ml and the specificity was 100%. A total of 29 people were tested HIV-1 positive with acute infection in a MSM cohort of Beijing during a 3 years period. This multiplex nested RT-PCR provides a useful tool for the rapid detection of acute HIV-1 infection. When used in combination with the 3(rd) generation ELISA, it can improve the detection rate of HIV infection, especially in the source limited regions.

  12. Estimating Divergence Time and Ancestral Effective Population Size of Bornean and Sumatran Orangutan Subspecies Using a Coalescent Hidden Markov Model

    DEFF Research Database (Denmark)

    Mailund, Thomas; Dutheil, Julien; Hobolth, Asger

    2011-01-01

    event has occurred to split them apart. The size of these segments of constant divergence depends on the recombination rate, but also on the speciation time, the effective population size of the ancestral population, as well as demographic effects and selection. Thus, inference of these parameters may......, and the ancestral effective population size. The model is efficient enough to allow inference on whole-genome data sets. We first investigate the power and consistency of the model with coalescent simulations and then apply it to the whole-genome sequences of the two orangutan sub-species, Bornean (P. p. pygmaeus......) and Sumatran (P. p. abelii) orangutans from the Orangutan Genome Project. We estimate the speciation time between the two sub-species to be thousand years ago and the effective population size of the ancestral orangutan species to be , consistent with recent results based on smaller data sets. We also report...

  13. Sampling and systematic error in a burrow index to measure relative population size in the common vole

    Czech Academy of Sciences Publication Activity Database

    Lisická, L.; Heroldová, Marta; Losík, J.; Tkadlec, Emil

    -, supp. (2006), s. 81 ISSN 1825-5272. [Rodens & Spatium /10./. 24.07.2006-28.07.2006, Parma] Institutional research plan: CEZ:AV0Z60930519 Keywords : common vole * population size Subject RIV: EH - Ecology, Behaviour

  14. Gene flow and effective population sizes of the butterfly Maculinea alcon in a highly fragmented, anthropogenic landscape

    DEFF Research Database (Denmark)

    Vanden Broeck, An; Maes, Dirk; Kelager, Andreas

    2017-01-01

    fragmentation as they occupy narrow niches or restricted habitat ranges. Here, we assess contemporary interpopulation connectedness of the threatened, myrmecophilous butterfly,Maculinea alcon, in a highly fragmented landscape.Weinferred dispersal, effective population sizes, genetic diversity and structure...

  15. Estimates of the Size and Characteristics of the Resident Nonimmigrant Population in the United States: January 2011

    Data.gov (United States)

    Department of Homeland Security — This report presents estimates of the size and characteristics of the resident nonimmigrant population in the United States. The estimates are daily averages for the...

  16. SEIR Model of Rumor Spreading in Online Social Network with Varying Total Population Size

    International Nuclear Information System (INIS)

    Dong Suyalatu; Deng Yan-Bin; Huang Yong-Chang

    2017-01-01

    Based on the infectious disease model with disease latency, this paper proposes a new model for the rumor spreading process in online social network. In this paper what we establish an SEIR rumor spreading model to describe the online social network with varying total number of users and user deactivation rate. We calculate the exact equilibrium points and reproduction number for this model. Furthermore, we perform the rumor spreading process in the online social network with increasing population size based on the original real world Facebook network. The simulation results indicate that the SEIR model of rumor spreading in online social network with changing total number of users can accurately reveal the inherent characteristics of rumor spreading process in online social network . (paper)

  17. SEIR Model of Rumor Spreading in Online Social Network with Varying Total Population Size

    Science.gov (United States)

    Dong, Suyalatu; Deng, Yan-Bin; Huang, Yong-Chang

    2017-10-01

    Based on the infectious disease model with disease latency, this paper proposes a new model for the rumor spreading process in online social network. In this paper what we establish an SEIR rumor spreading model to describe the online social network with varying total number of users and user deactivation rate. We calculate the exact equilibrium points and reproduction number for this model. Furthermore, we perform the rumor spreading process in the online social network with increasing population size based on the original real world Facebook network. The simulation results indicate that the SEIR model of rumor spreading in online social network with changing total number of users can accurately reveal the inherent characteristics of rumor spreading process in online social network. Supported by National Natural Science Foundation of China under Grant Nos. 11275017 and 11173028

  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. Hospitalization for Pneumonia among Individuals With and Without HIV Infection, 1995-2007: A Danish Population-Based, Nationwide Cohort Study

    DEFF Research Database (Denmark)

    Sogaard, Ole S; Lohse, Nicolai; Gerstoft, Jan

    2008-01-01

    ). Risk factors were assessed by Poisson regression. Results. @nbsp; The study included 3516 persons with HIV infection and 328,738 persons without HIV infection, which provided 23,677 person-years and 2,944,760 person-years of observation, respectively. Incidence rates of pneumonia in HIV......-infected individuals decreased from 50.6 hospitalizations per 1000 person-years (95% confidence interval [CI], 42.9-59.7 hospitalizations per 1000 person-years) during 1995-1996 to 19.7 hospitalizations per 1000 person-years (95% CI, 16.2-23.8 hospitalizations per 1000 person-years) during 2005-2007. Compared......-infected population. Methods. @nbsp; This was an observational cohort study conducted during 1995-2007. Each member of a Danish population-based nationwide cohort of HIV-infected individuals was matched with up to 99 control individuals from the general population. Data on age, mortality, emigration, and hospital...

  20. Prediction of the size of unerupted canines and premolars in an Iranian population

    Directory of Open Access Journals (Sweden)

    Mashaallah Khanehmasjedi

    2013-01-01

    Full Text Available Background and Aim: One of the important aspects of diagnosis and treatment planning in the mixed dentition is estimation of the size of unerupted permanent canines and premolars. One of the most commonly used the prediction methods are Tanaka and Johnston, which are based on data from a sample of Northern European descent children. The accuracy of this method when applied to a different ethnic population is questionable. The aim of this study was to determine the modified equations from Tanaka and Johnston for Iranian population. Materials and Methods: This study was an analytic and cross-sectional investigation with the randomized cluster sampling in Ahwaz. Fifty four students of 14-18 years age (32 girls, 22 boys were selected between 320 students and plaster models of their maxillary and mandibular arches were prepared. Subjects had fully erupted teeth, class I canine and molar relationship and presented no proximal caries or fillings, morphological anomalies, missing teeth or occlusal abrasion, and bruxism. The mesiodistal crown diameters of the permanent teeth were measured with using the sharpened boley gauge (accuracy 0.01 mm. The data were analyzed by using the regression correlation analyses and t-test. Results: The size of permanent canines and premolars were larger in maxilla than mandible and males than females. These values in Iran were different from other countries. Conclusion: In this study to predict the space (in mm required for alignment of unerupted canine and premolars in Iranian children, halve the sum of mesiodistal dimension of the four mandibular incisors and add the respective constants 10.5 for upper jaw and 10 for lower jaw.

  1. Diversity and effective population size of four horse breeds from microsatellite DNA markers in South-Central Mexico

    Directory of Open Access Journals (Sweden)

    J. F. Vázquez-Armijo

    2017-06-01

    Full Text Available The South-Central region of Mexico has experienced a sizeable introduction of purebred horses for recreational aims. A study was designed to assess effective population sizes and genetic diversity and to verify the genetic integrity of four horse breeds. Using a 12-microsatellite panel, Quarter Horse, Azteca, Thoroughbred and Creole (CRL horses were sampled and analysed for diversity and genetic structure. Genetic diversity parameters showed high numbers of heterozygous horses but small effective population sizes in all breeds. Population structure results suggested some degree of admixture of CRL with the other reference breeds. The highly informative microsatellite panel allowed the verification of diversity in introduced horse populations and the confirmation of small effective population sizes, which suggests a risk for future breed integrity.

  2. Results and evaluation of a survey to estimate Pacific walrus population size, 2006

    Science.gov (United States)

    Speckman, Suzann G.; Chernook, Vladimir I.; Burn, Douglas M.; Udevitz, Mark S.; Kochnev, Anatoly A.; Vasilev, Alexander; Jay, Chadwick V.; Lisovsky, Alexander; Fischbach, Anthony S.; Benter, R. Bradley

    2011-01-01

    In spring 2006, we conducted a collaborative U.S.-Russia survey to estimate abundance of the Pacific walrus (Odobenus rosmarus divergens). The Bering Sea was partitioned into survey blocks, and a systematic random sample of transects within a subset of the blocks was surveyed with airborne thermal scanners using standard strip-transect methodology. Counts of walruses in photographed groups were used to model the relation between thermal signatures and the number of walruses in groups, which was used to estimate the number of walruses in groups that were detected by the scanner but not photographed. We also modeled the probability of thermally detecting various-sized walrus groups to estimate the number of walruses in groups undetected by the scanner. We used data from radio-tagged walruses to adjust on-ice estimates to account for walruses in the water during the survey. The estimated area of available habitat averaged 668,000 km2 and the area of surveyed blocks was 318,204 km2. The number of Pacific walruses within the surveyed area was estimated at 129,000 with 95% confidence limits of 55,000 to 507,000 individuals. This value can be used by managers as a minimum estimate of the total population size.

  3. Size of the lower third molar space in relation to age in Serbian population.

    Science.gov (United States)

    Zelić, Ksenija; Nedeljković, Nenad

    2013-10-01

    It is considered that the shortage of space is the major cause of the third molar impaction. The aim of this study was to establish the frequency of insufficient lower third molar eruption space in Serbian population, to question the differences in this frequency in the subjects of different age, to determine the influence of the lower third molar space (retromolar space) size on third molar eruption, and to investigate a possible correlation between the size of gonial angle and the space/third molar width ratio. Digital orthopantomograms were taken from 93 patients divided into two groups: early adult (16-18 years of age) and adult (18-26) patients. Retromolar space, mesiodistal third molar crown width, gonial angle and eruption levels were measured. The space/third molar width in early adult subjects was smaller (p third molars erupted in case of enough space in both age groups (p third molar width ratio is more favorable in adult subjects. Gonial angle is not in correlation with the retromolar space/third molar width ratio.

  4. Eating patterns and portion size associated with obesity in a Swedish population.

    Science.gov (United States)

    Berg, Christina; Lappas, Georgios; Wolk, Alicja; Strandhagen, Elisabeth; Torén, Kjell; Rosengren, Annika; Thelle, Dag; Lissner, Lauren

    2009-02-01

    The objective of this study was to describe the association between meal pattern and obesity. The study is based on data from the INTERGENE research programme, and the study population consists of randomly selected women and men, aged 25-74, living in the Västra Götaland Region in Sweden. A total of 3610 were examined. Participants with measured BMI> or =30 were compared with others (BMIportions. Odds ratios (OR) with 95% confidence intervals were adjusted for age, sex, smoking and physical activity in logistic regression models. Being obese was significantly associated with omitting breakfast, OR 1.41 (1.05-1.90), omitting lunch OR 1.31 (1.04-1.66) and eating at night OR 1.62 (1.10-2.39). Obesity was also related to significantly larger self-reported portion sizes of main meals. No statistically significant relationship with intake of total energy was revealed. Thus, the results indicate that examination of meal patterns and portion sizes might tell us more about obesogenic food patterns than traditional nutrient analyses of food frequencies. Being obese was associated with a meal pattern shifted to later in the day and significantly larger self-reported portions of main meals.

  5. Pregnant and breastfeeding women: A priority population for HIV viral load monitoring.

    Science.gov (United States)

    Myer, Landon; Essajee, Shaffiq; Broyles, Laura N; Watts, D Heather; Lesosky, Maia; El-Sadr, Wafaa M; Abrams, Elaine J

    2017-08-01

    Landon Myer and colleagues discuss viral load monitoring for pregnant HIV-positive women and those breastfeeding; ART treatments can suppress viral load and are key to preventing transmission to the child.

  6. Development of an online database of typical food portion sizes in Irish population groups.

    Science.gov (United States)

    Lyons, Jacqueline; Walton, Janette; Flynn, Albert

    2013-01-01

    The Irish Food Portion Sizes Database (available at www.iuna.net) describes typical portion weights for an extensive range of foods and beverages for Irish children, adolescents and adults. The present paper describes the methodologies used to develop the database and some key characteristics of the portion weight data contained therein. The data are derived from three large, cross-sectional food consumption surveys carried out in Ireland over the last decade: the National Children's Food Survey (2003-2004), National Teens' Food Survey (2005-2006) and National Adult Nutrition Survey (2008-2010). Median, 25th and 75th percentile portion weights are described for a total of 545 items across the three survey groups, split by age group or sex as appropriate. The typical (median) portion weights reported for adolescents and adults are similar for many foods, while those reported for children are notably smaller. Adolescent and adult males generally consume larger portions than their female counterparts, though similar portion weights may be consumed where foods are packaged in unit amounts (for example, pots of yoghurt). The inclusion of energy under-reporters makes little difference to the estimation of typical portion weights in adults. The data have wide-ranging applications in dietary assessment and food labelling, and will serve as a useful reference against which to compare future portion size data from the Irish population. The present paper provides a useful context for researchers and others wishing to use the Irish Food Portion Sizes Database, and may guide researchers in other countries in establishing similar databases of their own.

  7. Ethnic differences in fetal size and growth in a multi-ethnic population.

    Science.gov (United States)

    Sletner, Line; Rasmussen, Svein; Jenum, Anne Karen; Nakstad, Britt; Jensen, Odd Harald Rognerud; Vangen, Siri

    2015-09-01

    Impaired or excessive fetal growth is associated with adverse short- and long-term health outcomes that differ between ethnic groups. We explored ethnic differences in fetal size and growth from mid pregnancy until birth. Data are from the multi-ethnic STORK-Groruddalen study, a population-based, prospective cohort of 823 pregnant women and their offspring in Oslo, Norway. Measures were z-scores of estimated fetal weight (EFW), head circumference (HC), abdominal circumference (AC) and femur length (FL), in gestational week 24, 32 and 37, measured by ultrasound, and similar measures at birth. Differences in fetal size and growth were assessed using separate Linear Mixed Models including all four time points, with ethnic Europeans as reference. In week 24 South Asian fetuses had smaller AC, but larger FL than Europeans, and slightly lower EFW (-0.17 SD (-0.33, -0.01), p=0.04). Middle East/North African fetuses also had larger FL, but similar AC, and hence slightly higher EFW (0.18 (0.003, 0.36), p=0.05). Both groups had slower growth of AC, FL and EFW from this time until birth, and had -0.61 SD (-0.73, -0.49) and -0.28 SD (-0.41, -0.15) lower birth weight respectively. Ethnic East Asians, on the other hand, were smaller throughout pregnancy and had -0.58 SD (-0.82, -0.34) lower birth weight. Significant ethnic differences remained after adjusting for maternal factors. We observed ethnic differences in fetal size and body proportions already in gestational week 24, and in fetal growth from this time until birth, which were only partly explained by key maternal factors. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. Estimated ventricle size using Evans index: reference values from a population-based sample.

    Science.gov (United States)

    Jaraj, D; Rabiei, K; Marlow, T; Jensen, C; Skoog, I; Wikkelsø, C

    2017-03-01

    Evans index is an estimate of ventricular size used in the diagnosis of idiopathic normal-pressure hydrocephalus (iNPH). Values >0.3 are considered pathological and are required by guidelines for the diagnosis of iNPH. However, there are no previous epidemiological studies on Evans index, and normal values in adults are thus not precisely known. We examined a representative sample to obtain reference values and descriptive data on Evans index. A population-based sample (n = 1235) of men and women aged ≥70 years was examined. The sample comprised people living in private households and residential care, systematically selected from the Swedish population register. Neuropsychiatric examinations, including head computed tomography, were performed between 1986 and 2000. Evans index ranged from 0.11 to 0.46. The mean value in the total sample was 0.28 (SD, 0.04) and 20.6% (n = 255) had values >0.3. Among men aged ≥80 years, the mean value of Evans index was 0.3 (SD, 0.03). Individuals with dementia had a mean value of Evans index of 0.31 (SD, 0.05) and those with radiological signs of iNPH had a mean value of 0.36 (SD, 0.04). A substantial number of subjects had ventricular enlargement according to current criteria. Clinicians and researchers need to be aware of the range of values among older individuals. © 2017 EAN.

  9. GONe: Software for estimating effective population size in species with generational overlap

    Science.gov (United States)

    Coombs, J.A.; Letcher, B.H.; Nislow, K.H.

    2012-01-01

    GONe is a user-friendly, Windows-based program for estimating effective size (N e) in populations with overlapping generations. It uses the Jorde-Ryman modification to the temporal method to account for age structure in populations. This method requires estimates of age-specific survival and birth rate and allele frequencies measured in two or more consecutive cohorts. Allele frequencies are acquired by reading in genotypic data from files formatted for either GENEPOP or TEMPOFS. For each interval between consecutive cohorts, N e is estimated at each locus and over all loci. Furthermore, N e estimates are output for three different genetic drift estimators (F s, F c and F k). Confidence intervals are derived from a chi-square distribution with degrees of freedom equal to the number of independent alleles. GONe has been validated over a wide range of N e values, and for scenarios where survival and birth rates differ between sexes, sex ratios are unequal and reproductive variances differ. GONe is freely available for download at. ?? 2011 Blackwell Publishing Ltd.

  10. A prospective study of seroprevalence of Toxoplasmosis in general population, and in HIV/AIDS patients in Bombay, India.

    Directory of Open Access Journals (Sweden)

    Meisheri Y

    1997-10-01

    Full Text Available Two hundred and seventy nine sera (age group 13-50 years were tested for antitoxoplasma IgG/IgM antibodies by ELISA techniques; the diagnostic titer for positive test is 10 iu/ml or > 1:100. Sera were obtained from (i 165 (100 men/65 women healthy adult voluntary blood donors (HIV, HBsAg, VDRL negative; (ii 89 consecutive HIV/AIDS patients (82 men/7 women; and (iii 25 patients (HIV negative: 12 men/13 women treated for cerebral Tuberculoma or Neurocysticercosis during this study from January 1996-June 1997. The overall seroprevalence was 30.9% (51/165 in the immunocompetent adult (group i 34% (34/100 men and 26.2% (17/65 in women [range: 10-899 iu/ml; (mean: 376.8]. In HIV infected hosts the seroprevalence [range: 21-340 iu/ml; (mean; 180] was 67.8% (56/82 men, 04/07 women. The seroprevalence was 20.5% (8/39, 32.8% (22/67, 34.8% (16/46 and 38.4% (5/13 in the 2nd, 3rd, 4th and 5th decades respectively in healthy adults. In HIV/AIDS patients, 69% (29/42 in the 3rd and 70.6% (24/34 in 4th decade were seropositive. The risk of cerebral Toxoplasmosis (encephalitis-02, granuloma-24 was 43.3% (26/60, mean 250 iu/ml. The seroprevalence was 28% in group iii (range 12-80 iu/ml, mean 21 iu/ml. Anti-toxo IgM was negative in all. Primary Toxoplasma infection appears to be subclinical and prevalent throughout life. T. gondii has emerged as an important opportunistic infection in HIV/AIDS patients in Bombay. Recrudescence of cerebral toxoplasmosis (CTOX is observed with low IgG response during mid-late stage of the disease, as seen in our patients (mean IgG 250 iu/ml, CD4+ = 283/cmm (range 43-504 in 5 patients. Primary prophylaxis for CTOX seems rationale and can be targeted to asymptomatic HIV/AIDS population at risk who are seropositive for T. gondii (mean IgG 111.5 iu/ml in our study. The very high predictive value of a negative test for TOX remains the best serological parameter for excluding acute episode of TOX.

  11. The abundance and pollen foraging behaviour of bumble bees in relation to population size of whortleberry (Vaccinium uliginosum.

    Directory of Open Access Journals (Sweden)

    Carolin Mayer

    Full Text Available Habitat fragmentation can have severe effects on plant pollinator interactions, for example changing the foraging behaviour of pollinators. To date, the impact of plant population size on pollen collection by pollinators has not yet been investigated. From 2008 to 2010, we monitored nine bumble bee species (Bombus campestris, Bombus hortorum s.l., Bombus hypnorum, Bombus lapidarius, Bombus pascuorum, Bombus pratorum, Bombus soroensis, Bombus terrestris s.l., Bombus vestalis s.l. on Vaccinium uliginosum (Ericaceae in up to nine populations in Belgium ranging in size from 80 m(2 to over 3.1 ha. Bumble bee abundance declined with decreasing plant population size, and especially the proportion of individuals of large bumble bee species diminished in smaller populations. The most remarkable and novel observation was that bumble bees seemed to switch foraging behaviour according to population size: while they collected both pollen and nectar in large populations, they largely neglected pollen collection in small populations. This pattern was due to large bumble bee species, which seem thus to be more likely to suffer from pollen shortages in smaller habitat fragments. Comparing pollen loads of bumble bees we found that fidelity to V. uliginosum pollen did not depend on plant population size but rather on the extent shrub cover and/or openness of the site. Bumble bees collected pollen only from three plant species (V.uliginosum, Sorbus aucuparia and Cytisus scoparius. We also did not discover any pollination limitation of V. uliginosum in small populations. We conclude that habitat fragmentation might not immediately threaten the pollination of V. uliginosum, nevertheless, it provides important nectar and pollen resources for bumble bees and declining populations of this plant could have negative effects for its pollinators. The finding that large bumble bee species abandon pollen collection when plant populations become small is of interest when

  12. Modeling the population-level effects of male circumcision as an HIV-preventive measure: a gendered perspective.

    Directory of Open Access Journals (Sweden)

    Jonathan Dushoff

    Full Text Available BACKGROUND: Evidence from biological, epidemiological, and controlled intervention studies has demonstrated that male circumcision (MC protects males from HIV infection, and MC is now advocated as a public-health intervention against HIV. MC provides direct protection only to men, but is expected to provide indirect protection to women at risk of acquiring HIV from heterosexual transmission. How such indirect protection interacts with the possibility that MC campaigns will lead to behavior changes, however, is not yet well understood. Our objective here is to investigate the link between individual-level effects of MC campaigns and long-term population-level outcomes resulting from disease dynamics, looking at both genders separately, over a broad range of parameters. METHODS AND FINDINGS: We use simple mathematical models of heterosexual transmission to investigate the potential effects of a circumcision scale-up, combined with possible associated behavioral disinhibition. We examine patterns in expected long-term prevalence using a simple equilibrium model based on transmission factors, and validate our results with ODE-based simulations, focusing on the link between effects on females and those on males.We find that the long-term population-level effects on females and males are not strongly linked: there are many possible ways in which an intervention which reduces prevalence in males might nonetheless increase prevalence in females. CONCLUSIONS: Since an intervention that reduces long-term male prevalence could nonetheless increase long-term female prevalence, MC campaigns should explicitly consider both the short-term and long-term effects of MC interventions on females. Our findings strongly underline the importance of pairing MC programs with education, support programs and HIV testing and counseling, together with other prevention measures.

  13. The effective size of the Icelandic population and the prospects for LD mapping: inference from unphased microsatellite markers

    DEFF Research Database (Denmark)

    Bataillon, Thomas; Mailund, Thomas; Thorlacius, Steinunn

    2006-01-01

    on scaled recombination rates from patterns of LD. Patterns of LD in Iceland suggest a genome-wide scaled recombination rate of ρ* = 200 [130–330] per cM which is equivalent to a long term effective population size of ~5000 in the range of estimates recently reported in three populations using extensive...

  14. HIV Research with Men who Have Sex with Men (MSM: Advantages and Challenges of Different Methods for Most Appropriately Targeting a Key Population

    Directory of Open Access Journals (Sweden)

    Ana Gama

    2017-05-01

    Full Text Available The difficulty in accessing hard-to-reach populations as men who have sex with men presents a dilemma for HIV surveillance as their omission from surveillance systems leaves significant gaps in our understanding of HIV/AIDS epidemics. Several methods for recruiting difficult-to-access populations and collecting data on trends of HIV prevalence and behavioural factors for surveillance and research purposes have emerged. This paper aims to critically review different sampling approaches, from chain-referral and venue-based to respondent-driven, time-location and internet sampling methods, focusing on its main advantages and challenges for conducting HIV research among key populations, such as men who have sex with men. The benefits of using these approaches to recruit participants must be weighed against privacy concerns inherent in any social situation or health condition. Nevertheless, the methods discussed in this paper represent some of the best efforts to effectively reach most-at-risk subgroups of men who have sex with men, contributing to obtain unbiased trends of HIV prevalence and HIV-related risk behaviours among this population group.

  15. Longitudinal Trends in the Prevalence of Detectable HIV Viremia: Population-Based Evidence From Rural KwaZulu-Natal, South Africa.

    Science.gov (United States)

    Vandormael, Alain; Bärnighausen, Till; Herbeck, Joshua; Tomita, Andrew; Phillips, Andrew; Pillay, Deenan; de Oliveira, Tulio; Tanser, Frank

    2018-04-03

    The prevalence of detectable viremia has previously been used to infer the potential for ongoing human immunodeficiency virus (HIV) transmission. To date, no study has evaluated the longitudinal change in the prevalence of detectable viremia within the HIV-positive community (PDV+) and the entire population (PDVP) using data from a sub-Saharan African setting. In 2011, 2013, and 2014, we obtained 6752 HIV-positive and 15415 HIV-negative test results from a population-based surveillance system in the KwaZulu-Natal province of South Africa. We quantified the PDV+ as the proportion of the 6752 HIV-positive results with a viral load >1550 copies/mL and the PDVP as the proportion of the 6752 HIV-positive and 15415 HIV-negative results with a viral load >1550 copies/mL. Between 2011 and 2014, the PDV+ decreased by 16.5 percentage points (pp) for women (from 71.8% to 55.3%) and 10.6 pp for men (from 77.8% to 67.2%). However, a steady rise in the overall HIV prevalence, from 26.7% to 32.4%, offset the declines in the PDV+ for both sexes. For women, the PDVP decreased by only 2.1 pp, from 21.3% to 19.2%, but for men, the PDVP actually increased by 1.6 pp, from 14.6% to 16.2%, over the survey period. The PDV+, which is currently being tracked under the UNAIDS 90-90-90 targets, may not be an accurate indicator of the potential for ongoing HIV transmission. There is a critical need for countries to monitor and report the prevalence of detectable viremia among all adults, irrespective of HIV status.

  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