Research On The Factors Associated With HIV-1 Infection In MSMs And HIV-1 Molecular Epidemiology In Yunnan

Objective We designed the study to reveal the characteristics of MSMs' knowledge on AIDS prevention and their behaviors, factors related to HIV infection and the epidemic characteristics of several sexually transmitted diseases, and to provide evidence for better AIDS and STIs prevention in Yunnan province.Studying on characteristics of HIV-1 subtypes and recombinants circulated come from MSMs and common people in Yunnan province.Methods Characteristics of sexual behavior in MSMs and its influencing factors were investigated by questionnaire. Double input method was employed in EpiData3.1.HIV-1 strains were selected from store centre of Yunnan province by stratified random sampling. Gag and env gene in HIV-1 were amplified by nest PCR, and PCR products were sequenced. We analyzed all sequences by Mega, Simplot, Entropy, N-GlycoSite, VESPA, and Wetcat for phylogenetic tree, bootscanning analysis, amino acid sequences analysis, N-GlycoSite analysis, analysis of V3 loop, and coreceptor forecast.The distribution of HIV-1 subtypes were analyzed by SPSS15.0. Nonparametric tests were performed when analyzing the data. Data were analyzed by SPSS 15.0 and nonparametric tests were performed.Respondents Male adults living in Kunming who have experienced homosexual behavior (oral sex or anal sex) during the past 6 months, would like to participant the investigation and receive serological test for HIV and other infectious diseases. Serum or plasma samples were studied including 64 samples come from MSMs and untreated HIV/AIDS infectors which were new reported in 2006, in Yunnan province at random.Results A total of 472 MSMs aged 18 to 69 (28.1±8.6, mean±standard deviation) years were recruited, of which 272 were gays(57.6%),192 were bisexuals (40.7%). It was shown that the respondents are younger than the other high risk behavior people. The respondents who aged 18-24 and 25-35 accounted for 43.2% (204) and 39.8%(188) respectively.69.5%(328) of MSMs are unmarried and 19.1% of MSMs are marriage.31.4% of MSMs (148 cases) have received high school or higher education,208 persons graduated from college, which accounts to 44.1%. There are many kinds of occupations among MSMs,35.4% of which are service workers in commercial company,16.1% are students, and 12.7% are managers or staff.384 cases are Han, and minority includes 12 nationalities such as Bai, Yi, and Miao.The general rate for awareness of knowledge on HIV/AIDS prevention is 94.9%. Those who received college education have the highest awareness level (98.6%), contrast to primary school (73.7%).Low condom use rate among MSMs was reported, while this rate in last male anal sexual activity and 100% rate of condoms in the past 6 months are 72% and 47.5% respectively.22.5% of MSMs conduct heterosexual sexual behavior, and condom use rate is lower than those gays. During the last 6 months 5.3% of MSMs get homosexual services by paying and 83.3% of them use condom in all sexual activities.4.6% of them are MB (money boy), while 66.7% of them conduct 100% condom using.3% of MSMs were drug users, and no one is sharing of syringes.Prevalence rate of HIV, syphilis, HCV and HSV-2 infection is 9.3%,6.6%,1.9% and 16.3% respectively. The results also show that there is high prevalence of HIV and HSV-2 among MSMS. The rate of HIV co-infected with Syphilis, HCV and HSV-2 are 29%,30% and 9.1%. MSM co-infected syphilis or hepatitis C is easier to infect HIV virus (p<0.05). In addition, there were 61 people (13%) who report they got STI symptoms during the last year. The factors associated with HIV infection in MSMs are:the rate of infection with syphilis or HCV, sexual preference,100% of condom use, homosexual conduct commercial activities and vocational educational background.290 samples of HIV-I infector come from 16 prefectures in Yunnan,whose mean age was 32±11 (from age 1to age 72) years. The transmitting ways of HIV include intravenous drug user (IDU), heterosexual transmission, mother to child (MTC), and MSM (men who have sex with men). The data are of representative Yunnan province.There are 13 subtypes or recombinants of HIV-1 in Yunnan,and CRF08_BC is the most popular subtype accounted for 39.1%, and followed by CRF01_AE and CRF07_BC which accounted for 22.4% and 18.9% respectively. Subtype C and B are account for 5.9% and 4.5% respectively after correction,which were less popular in Yunnan. New recombinants of HIV-1 strain were founded including:BC,01_C, 08₀1, C₀1,01_BC,0701, B₀1, and BC₀1. All of them accounted for 9.2%, and they became the fourth popular strains in Yunnan. Simplot analysis confirmed that new recombinant form become more complex.We concluded that new recombinants are derived of the HIV-1 outbreak in Yunnan, or recombinated in long time transmission in Yunnan.CRF08_BC and CRF07_BC were dominated(79%) in the IDUs; While the strains of CRF01_AE are mainly prevalent in MTCs and people who have heterosexual contact experience. Distribution characteristics of HIV-1 subtypes in different prefectures of Yunnan Province were as follows:The recombinants become more and more complex and diversity in many of prefectures; There were 12 prefectures (75%,12/16) that were found new recombinants in the states and city in the province (twelve-sixteenths prefectures), especially in the western areas of Yunnan, such as Dehong, Lijiang, Nujiang, Xishuangbanna, and Baoshan, accounted for more than 10% totally. While the HIV-1 subtypes of distribution was no significant differences in gender, ethnicity, and age.The subtype of CRF01_AE strains was the dominated subtype in MSMs, and followed by CRF07_BC accounted for 22%,and CRF08_BC only accounted for 5%. The distribution of subtypes was difference among people with different transmited ways significantly. The phylogeny tree showed that the trains come from MSMs clustered together, and means that the HIV-1 strains were segregated from other population.The average genetic distances of gag gene indicated as follows:subtype B, CRF01_AE, CRF07_BC, BC, and CRF08_BC. We infer that B subtype is earliest strain transmitted into Yunnan, and followed by CRF01_AE. The genetic analysis of env gene also can get same conclusion. The average genetic distances of MSMs of env and gag are lewer than other high risk population. It seems to show that the strains of HIV-1 dominate in MSMs recently.The recombination analysis showed the homology of nucleotide between new recombinants and C, B, CRF08_BC, CRF07_BC, and CRF01_AE strains which had been dominated in Yunnan in the past 20 years. We could infer that it may be the recombination of the past epidemic strains in Yunnan. Env sequences genetic diversity analysis showed that PNGS of homosexual were more than heterosexual contact population and IDUs. The amino acids characteristic of V3-V4 sequence showed there is more diversity of amino acids among heterosexual transmission people, followed by the MSMs, then IDUs.There are 6 types of four peptides in V3 loop:GPGR, GPGH, GLGQ, GPGQ, GPGK and GQGR, and GPGQ account for 95.0%. Major strains of CRF07_BC, CRF08_BC and B may use CCR5 to entry CD4 T lymphocyte, and account for more than 90%. It was about 60.9% of CRF01_AE strains could use CXCR4, but it need to be research further.Conclusions MSMs are young strong labours with high risk of HIV infection. Most of them have good education in general, however, the good awareness of knowledge on HIV and their behavior were separated because of the unprotected sexual activities. The condom use rate is still low. Unprotected anal sex, multiple sex partners, and bisexual behaviors were common in this group. Multiplesexual partners and other high risk behaviors while having sex with men or women among MSMs represents a unique risk group within the population of MSM that may bridged the HIV transmission between HIV high risk group and common people. Few MSMs take good use of health resources. If there are no effective intervention measures, the increased HIV prevalence in MSMs would aggravate AIDS epidemic in China. High prevalence of HIV among MSMs, co-infected with HSV-2, syphilis, hepatitis C and other sexually transmitted diseases are common among MSMs. Other STDs prevention and control should be strengthened in AIDS prevention.The strains of CRF01_AE mainly circulate in such population experienced sexual contacting. We should take good intervention measures to reduce the prevalence of HIV-1 in such high risk of activity. Because of new recombinants distribute in western of Yunnan where lies to Dehong with serious HIV epidemic; and there are some prefectures far away from frontier that have been found new strains of recombination. So government should focus on Dehong and other prefectures nearby to avoid new recombinants spread further. In MSMs, the main circulating strains are CRF01_AE, followed by CRF07_BC. If it is not controlled well, these two strains would recombinate in them. The strains of CRF01_AE, CRF07_BC and new recombinants would widespread into the general people by the "bridge crowd"...