The Origin and Evolutionary History of HIV-1 Subtype C in Senegal

Background: The classification of HIV-1 strains in subtypes and Circulating Recombinant Forms (CRFs) has helped in tracking the course of the HIV pandemic. In Senegal, which is located at the tip of West Africa, CRF02_AG predominates in the general population and Female Sex Workers (FSWs). In contrast, 40% of Men having Sex with Men (MSM) in Senegal are infected with subtype C. In this study we analyzed the geographical origins and introduction dates of HIV-1 C in Senegal in order to better understand the evolutionary history of this subtype, which predominates today in the MSM population Methodology/Principal Findings: We used a combination of phylogenetic analyses and a Bayesian coalescent-based approach, to study the phylogenetic relationships in pol of 56 subtype C isolates from Senegal with 3,025 subtype C strains that were sampled worldwide. Our analysis shows a significantly well supported cluster which contains all subtype C strains that circulate among MSM in Senegal. The MSM cluster and other strains from Senegal are widely dispersed among the different subclusters of African HIV-1 C strains, suggesting multiple introductions of subtype C in Senegal from many different southern and east African countries. More detailed analyses show that HIV-1 C strains from MSM are more closely related to those from southern Africa. The estimated date of the MRCA of subtype C in the MSM population in Senegal is estimated to be in the early 80's. Conclusions/Significance: Our evolutionary reconstructions suggest that multiple subtype C viruses with a common ancestor originating in the early 1970s entered Senegal. There was only one efficient spread in the MSM population, which most likely resulted from a single introduction, underlining the importance of high-risk behavior in spread of viruses

Female genital mutilation/cutting in Italy: an enhanced estimation for first generation migrant women based on 2016 survey data

Background: Migration flows of women from Female Genital Mutilation/Cutting practicing countries have generated a need for data on women potentially affected by Female Genital Mutilation/Cutting. This paper presents enhanced estimates for foreign-born women and asylum seekers in Italy in 2016, with the aim of supporting resource planning and policy making, and advancing the methodological debate on estimation methods. Methods: The estimates build on the most recent methodological development in Female Genital Mutilation/ Cutting direct and indirect estimation for Female Genital Mutilation/Cutting non-practicing countries. Direct estimation of prevalence was performed for 9 communities using the results of the survey FGM-Prev, held in Italy in 2016. Prevalence for communities not involved in the FGM-Prev survey was estimated using to the 'extrapolationof- FGM/C countries prevalence data method' with corrections according to the selection hypothesis. Results: It is estimated that 60 to 80 thousand foreign-born women aged 15 and over with Female Genital Mutilation/Cutting are present in Italy in 2016. We also estimated the presence of around 11 to 13 thousand cut women aged 15 and over among asylum seekers to Italy in 2014-2016. Due to the long established presence of female migrants from some practicing communities Female Genital Mutilation/Cutting is emerging as an issue also among women aged 60 and over from selected communities. Female Genital Mutilation/Cutting is an additional source of concern for slightly more than 60% of women seeking asylum. Conclusions: Reliable estimates on Female Genital Mutilation/Cutting at country level are important for evidencebased policy making and service planning. This study suggests that indirect estimations cannot fully replace direct estimations, even if corrections for migrant socioeconomic selection can be implemented to reduce the bias

Estimating the contribution of key populations towards spread of HIV in Dakar, Senegal

Introduction Key populations including female sex workers (FSW) and men who have sex with men (MSM) bear a disproportionate burden of HIV. However, the role of focusing prevention efforts on these groups for reducing a country’s HIV epidemic is debated. We estimate the extent to which HIV transmission amongst FSW and MSM contributes to overall HIV transmission in Dakar, Senegal, using a dynamic assessment of the population attributable fraction (PAF). Methods A dynamic transmission model of HIV among FSW, their clients, MSM and the lower-risk adult population was parameterized and calibrated within a Bayesian framework using setting-specific demographic, behavioural, HIV epidemiological, and antiretroviral treatment (ART) coverage data for 1985-2015. We used the model to estimate the 10-year PAF of commercial sex between FSW and their clients, and sex between men, to overall HIV transmission (defined as the percentage of new infections prevented when these modes of transmission are removed). Additionally, we estimated the prevention benefits associated with historical increases in condom use and ART uptake, and impact of further increases in prevention and treatment. Results The model projections suggest that unprotected sex between men contributed to 42% (2.5 to 97.5th percentile range 24-59%) of transmissions between 1995-2005, increasing to 64% (37-79%) from 2015-2025. The 10-year PAF of commercial sex is smaller, diminishing from 21% (7-39%) in 1995 to 14% (5-35%) in 2015. Without ART, 49% (32-71%) more HIV infections would have occurred since 2000, when ART was initiated, whereas without condom use since 1985, 67% (27-179%) more HIV infections would have occurred, and the overall HIV prevalence would have been 60% (29-211%) greater than what it is now. Further large decreases in HIV incidence (68%) can be achieved by scaling up ART in MSM to 74% coverage and reducing their susceptibility to HIV by a two-thirds through any prevention modality. Conclusions Unprotected sex between men may be an important contributor to HIV transmission in Dakar, due to suboptimal coverage of evidence-based interventions. Although existing interventions have effectively reduced HIV transmission amongst adults, it is crucial that further strategies address the unmet need amongst MSM