Prevalence and incidence of HIV-1 infection in a community-based men who have sex with men (MSM) cohort in Ulaanbaatar, Mongolia.

The number of HIV-1-infected men who have sex with men (MSM) Mongolian patients started to increase steeply just before 2011. We started collaborative work with community-based organizations that promote safer sex and HIV testing for MSM since mid-2010. Since early 2013, the Mongolian Government has implemented the treat-all strategy for MSM. To determine the efficacy of these countermeasures, we established an MSM cohort in the capital of Mongolia, Ulaanbaatar, in December 2013. HIV antibody was examined at every visit by rapid test. Syphilis was also examined to monitor their sexual behavior. Clients positive for either rapid test were referred to the National Center for Communicable Diseases, Ulaanbaatar, to confirm the results and treatment. Since safer sex promotion is one of the purposes of this cohort, HIV-positive clients were also eligible to participate. A total of 849 MSM were registered and 2,409 HIV/syphilis tests were conducted until December 2017. During this period, 499 (58.8%) clients visited the testing sites repeatedly. Among the 849 clients, HIV-1 infection was confirmed in 83 at registration (prevalence of HIV- 1: 9.8%). One HIV-1 seroconverter was identified (from negative to positive), resulting in incidence of HIV-1 of 0.10/100 person-years (PY). Syphilis was positive in 144 cases at registration (syphilis prevalence: 17.0%), and 53 new syphilis infection cases were diagnosed during the same period, with an incidence of 5.66/100 PY. Despite the high prevalence of HIV-1, the incidence was very low. The results suggest that countermeasures for HIV-1 prevention seem effective in this cohort, however, we still need further strategies for syphilis control.

The second molecular epidemiological study of HIV infection in Mongolia between 2010 and 2016.

OBJECTIVE: Our previous 2005-2009 molecular epidemiological study in Mongolia identified a hot spot of HIV-1 transmission in men who have sex with men (MSM). To control the infection, we collaborated with NGOs to promote safer sex and HIV testing since mid-2010. In this study, we carried out the second molecular epidemiological survey between 2010 and 2016 to determine the status of HIV-1 infection in Mongolia. METHODS: The study included 143 new cases of HIV-1 infection. Viral RNA was extracted from stocked plasma samples and sequenced for the pol and the env regions using the Sanger method. Near-full length sequencing using MiSeq was performed in 3 patients who were suspected to be infected with recombinant HIV-1. Phylogenetic analysis was performed using the neighbor-joining method and Bayesian Markov chain Monte Carlo method. RESULTS: MSM was the main transmission route in the previous and current studies. However, heterosexual route showed a significant increase in recent years. Phylogenetic analysis documented three taxa; Mongolian B, Korean B, and CRF51_01B, though the former two were also observed in the previous study. CRF51_01B, which originated from Singapore and Malaysia, was confirmed by near-full length sequencing. Although these strains were mainly detected in MSM, they were also found in increasing numbers of heterosexual males and females. Bayesian phylogenetic analysis estimated transmission of CRF51_01B into Mongolia around early 2000s. An extended Bayesian skyline plot showed a rapid increase in the effective population size of Mongolian B cluster around 2004 and that of CRF51_01B cluster around 2011. CONCLUSIONS: HIV-1 infection might expand to the general population in Mongolia. Our study documented a new cluster of HIV-1 transmission, enhancing our understanding of the epidemiological status of HIV-1 in Mongolia.

Evolving understanding of the epidemiology of HIV and prevention needs among men who have sex with men in Ulaanbaatar, Mongolia.

This study describes HIV and syphilis bio-behavioral survey conducted among 200 men who have sex with men (MSM) recruited via respondent-driven sampling (RDS) between January 4 and February 1, 2012 in Ulaanbaatar, Mongolia. Participants were administered a structured questionnaire and data were analyzed with RDS-network program in STATA. Of 196 participants who agreed to be tested for HIV and syphilis, 21 (10.7 %; weighted 7.5; 95 % CI: 4.9, 11.4) and 8 (4.1 %; weighted 3.4; 95 % CI: 1.7, 6.7) were positive for HIV and syphilis, respectively. Exposure to HIV prevention programs in the last 12 months was reported by 51.8 % (weighted 33.6; 95 % CI: 27.6, 40.1) of participants. This study found high HIV prevalence and limited uptake of HIV prevention services among MSM in Mongolia. Given the concentrated HIV epidemic among MSM in Mongolia, HIV prevention, treatment and care services should focus on MSM as the population group most affected by HIV.