The changing trends of HIV-1 prevalence and incidence from sentinel surveillance of five sub-populations in Yunnan, China, 2001-2010.

BACKGROUND: Yunnan is one of the provinces hardest-hit by HIV in China. To understand HIV epidemic dynamics and evaluate prevention effectiveness, we studied the changing trends in HIV-1 prevalence and incidence among five sub-populations in Yunnan. METHODS: Consecutive sentinel surveillances were conducted among people who inject drugs (PWID), male sexually transmitted diseases (STD) clinic attendees, and pregnant women for 2001-2010,female sex workers (FSWs) for 2007-2010, men who have sex with men (MSM) for 2008-2010. For the newly diagnosed HIV-seropositive samples, the recent infections were determined with BED-capture enzyme immunoassay (BED-CEIA), based on which HIV incidence was calculated for each sub-population using McDougal algorithm. RESULTS: From 231,117 individuals, 6,107 HIV-positive samples were tested with BED-CEIA, among which 964 samples were identified as recent infections. In PWID, HIV prevalence for 2001-2010 was between 27.16% and 18.35%, while the estimated incidence rate significantly decreased from 11.68% in 2001 to 1.70% in 2010. Among male STD clinic attendees, both the HIV prevalence (from 3.62% in 2001 to 1.73% in 2010) and incidence (from 1.10% in 2001 to 0.40% in 2010) showed a significant decreasing trend. In FSWs, the HIV prevalence for 2007-2010 kept stable (between 2.46% and 1.95%), while the HIV incidence significantly decreased (from 0.71% in 2007 to 0.31% in 2010). In MSM, the HIV prevalence (between 11.78% and 9.42%) and incidence (between 6.01% and 8.38%) remained stable at a relatively high level for 2008-2010. In pregnant women, the HIV prevalence (between 0.44% and 0.30%) and incidence (between 0.15% and 0.08%) remained stable for 2001-2010. CONCLUSION: The HIV incidences in PWID, male STD clinic attendees and FSWs showed the decreasing trend, supporting a positive effect of prevention strategies for these sub-populations. MSM with the highest HIV incidence have become the sub-population most at risk. In most sub-populations, the HIV prevalence did not decline, suggesting the disease burden is still heavy. These findings are valuable for developing HIV prevention strategies in Yunnan.

[Analysis of the risky behaviors among HIV positive female sex workers].

OBJECTIVE: To analyze the characteristics of risky behaviors among different age groups of HIV positive female sex workers, and to explore the strengthening of their management. METHODS: From January to June 2014, 22 814 female sex workers were investigated and tested HIV in 117 sentinel surveillance sites in Yunnan Province, and 181 were confirmed to be HIV antibody positive, who accepted questionnaire surveys. According to the age, the participants were divided into the < 35 years old age group and ≥ 35 years old age group. The demographic characteristics, knowledge about HIV/AIDS and related risk behaviors characteristics of the two groups were obtained via questionnaire surveys among 181 HIV positive female sex workers, and in-depth qualitative interviews were conducted from among 12 HIV positive sex workers. RESULTS: HIV antibody positive rate was 0.8% (181), the age of the 181 subjects were (35.83 ± 9.17) years old, 76 cases (42.0%) were < 35 years old, and 105 cases (58.0%) were ≥ 35 years old. The differences of marital status, workplace class, the last work site among two groups were statistically significant (χ(2) = 20.80, 28.32, 7.83; P < 0.001, P < 0.001, P = 0.020, respectively). Among 181 HIV, the proportion of AIDS awareness was 95.6% (173); the proportion of drug use among ≥ 35 years old age group was 51.4% (54), which was higher than that in < 35 years old age group (34.2%, 26/76) (χ(2) = 5.30, P = 0.021). 96.7% (175) received condom promotion or HIV counseling and testing in the past year. The proportion of continuing to engage in sexual services over 5 years after HIV infection was 48.5% (51/105) and the proportion of receiving antiretroviral treatment was 69.5% (73/105) in ≥ 35 years old age group, which were higher than those in the < 35 age group (30.2% (23/76), 52.6% (40/76); χ(2) = 12.26, 5.36; P = 0.002, 0.021, respectively). In-depth interviews among 12 HIV positive female sex workers found that regular clients, not consistent use of condoms were the main cause of no condom use. Economic and livelihood factors are important reasons for continuing to engage in sexual services among HIV positive sex workers. CONCLUSION: HIV positive sex workers still have high risk behaviors including continuing to engage in commercial sexual service and no condom use after knowing their HIV infection status, and the proportion of using drugs in the ≥ 35 years old group was higher than that in < 35 years old group.

[An analysis of high risk behaviors among female sex workers in Yunnan province in 2013].

OBJECTIVE: To understand the high risk behaviors of female sex workers (FSWs) in Yunnan province in 2013. METHODS: A cross-sectional investigation was conducted during April to June, 2013 in Yunnan province, census was used to the investigation where the number of FSWs was close to 200, while probability sampling was used where the number of FSWs was obviously over 200. A total of 25 574 cases were investigated, and data on demography and risk behaviors were obtained by questionnaires one by one. RESULTS: A total of 25 574 cases were investigated, AIDS awareness among FSWs in high-level places, middle-level places and low-level place were 98.8% (92/7 401), 98.6% (150/10 995), and 96.0% (281/6 655). FSWs from low-level place had a lower rate than those from the other two types of places (P < 0.01). The rate of condom use each time when having sex with clients within the recent one month among FESs from high-level places, middle-level places and low-level place were 93.4% (6 307/6 755), 93.8% (10 109/10 782) and 90.4% (6 053/6 697), and the FSWs working in low-level place had a lower rate than those from the other two types of places(P < 0.01). Multi-factor logistic regression analysis showed that the following had a lower rate of condom use: the FSWs working in low-level place (OR = 1.56, 95% CI:1.36-1.79; OR = 1.36, 1.16-1.59), over 30 years old (OR = 0.77, 95%CI:0.69-0.85), Yunnan citizen (OR = 0.88, 95% CI:0.77-1.00), minority (OR = 1.32, 95% CI:1.16-1.50), under senior high school (OR = 0.61, 95%CI:0.49-0.75), married (OR = 0.81, 95% CI:0.71-0.92), living together (OR = 0.70, 95% CI:0.51-0.96), divorced or lost spouses (OR = 0.81, 95% CI:0.65-1.02), worked less than 6 months in local areas (OR = 1.74, 95% CI:1.34-2.27), drug users (OR = 1.65, 95% CI:1.11-2.46), had not accepted HIV interventions (OR = 2.91, 95% CI:2.36-3.58), had no knowledge about AIDS (OR = 4.50, 95% CI:3.48-5.82). The main reasons for not using condoms were the clients' unwilling to use, which accounted for 47.62% (270/567). The total rate of drug use was 1.0% (264/25 567) and the FSWs working in middle-level places had the highest rate of injecting drugs, which accounted for 0.6% (70/11 141). The FSWs working in low-level places had a higher rate than those who worked in high-level places and middle-level places in venereal diseases, which accounted for 1.2% (85/6 934) (P < 0.01). The rate of receiving effective interventions was 96.7% (24 717/25 574), the rate of accepting treatment and clean needles among drug users was 21.6% (57/264). CONCLUSION: High risk behaviors were serious among the FSWs who worked in low-level places, especially among the olders, the minorities, people who had lower educational level, the new-comer and drug users, which indicated that more attention needs to be paid among these populations.

[Prevalence of high risk behaviors in HIV infected persons aged ≥50 years in selected counties of Yunnan province].

OBJECTIVE: To understand the prevalence of high risk behaviors and influencing factors among HIV infected persons aged ≥50 years. METHODS: Face to face questionnaire interview was conducted among the HIV infected persons selected in Jianshui, Gejiu and Mengzi counties in Yunnan province through random sampling in June 2015. The sample size was 450. RESULTS: Among the HIV infected persons surveyed, 41.2% (122/296) had sexual behaviors with their spouses during past year, and the consistent condom use rate was 66.4% (81/122). Among the HIV infected males, 8.9% (28/313) had commercial sexual behaviors during past year, and the consistent condom use rate was 17.9% (5/28). Among the HIV infected females, 0.7% were still engaged in commercial sex service during past year. Among the 450 HIV infected persons, 32 (7.1%) reported having casual sex behaviors during past years, and the consistent condom use rate was 18.7% (6/32). The rate of commercial sexual behavior in urban residents (13.4%, 19/115) was higher than that in rural residents (4.5%, 9/198), the difference was statistically significant (χ(2)=11.715, P=0.001). The risk factors for commercial sex behaviors included lack of family and social support, aged 50-59 years, living in urban area, higher income and being male. The risk factors for using no condom included living in rural area, lower education level, lack of family and social support and higher income. CONCLUSIONS: Risk sex behaviors are still prevalent in HIV infected people aged >50 years, which exacerbated HIV transmission. Further efforts should be focused on the education about AIDS prevention and control and promoting protected sexual behaviors. Additional effort should be done to improve the family and social support for HIV infected people aged >50 years. Moreover, comprehensive intervention for low-paid female sex workers also needs to be strengthened.

A Novel Classification Algorithm Based on Incremental Semi-Supervised Support Vector Machine.

For current computational intelligence techniques, a major challenge is how to learn new concepts in changing environment. Traditional learning schemes could not adequately address this problem due to a lack of dynamic data selection mechanism. In this paper, inspired by human learning process, a novel classification algorithm based on incremental semi-supervised support vector machine (SVM) is proposed. Through the analysis of prediction confidence of samples and data distribution in a changing environment, a "soft-start" approach, a data selection mechanism and a data cleaning mechanism are designed, which complete the construction of our incremental semi-supervised learning system. Noticeably, with the ingenious design procedure of our proposed algorithm, the computation complexity is reduced effectively. In addition, for the possible appearance of some new labeled samples in the learning process, a detailed analysis is also carried out. The results show that our algorithm does not rely on the model of sample distribution, has an extremely low rate of introducing wrong semi-labeled samples and can effectively make use of the unlabeled samples to enrich the knowledge system of classifier and improve the accuracy rate. Moreover, our method also has outstanding generalization performance and the ability to overcome the concept drift in a changing environment.

[Change trend of HIV/AIDS related risk factors and influencing factors among men who have sex with men in Yunnan, 2010-2013].

OBJECTIVE: To understand the change trend of the awareness rate of HIV/AIDS related knowledge, risk behaviors among men who have sex with men (MSM) in Yunnan and the factors influencing their condom use, and evaluate the effect of comprehensive intervention. METHODS: The data about the MSM's demographic information, HIV/AIDS related knowledge awareness, and sex behavior, condom use, drug use and intervention receiving were obtained from AIDS sentinel surveillance among MSM in Yunnan province during 2010-2013 to conduct change trend and influencing factor analysis. RESULTS: A total of 9 073 MSM were surveyed. The awareness rate of the HIV/AIDS related knowledge, homosexual behavior and condom use rate increased year by year (P < 0.01). The condom use rate was lower in heterosexual behavior, and the drug use rate and sexually transmitted disease prevalence declined with year (P < 0.01). Multivariate logistic regression analysis indicated that cohabiting, low awareness of HIV/AIDS related knowledge, being from other provinces, local residence for <1 year, low education level, receiving no intervention, frequent anal sex and receiving no HIV/AIDS detection were the risk factors influencing persistent condom use among MSM. CONCLUSION: The effect of HIV/AIDS comprehensive intervention was observed after 4 years implantation, but most of the index were at low level. More attention should be paid to the intervention among MSM with cohabiting habit, low education level, frequent anal sex, and heterosexual sex. It is necessary to expand intervention coverage, strengthen HIV test and promote condom use among MSM.

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

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

[Analysis on genotypes of hepatitis C virus among intravenous drug users in Kunming, Yunnan].

OBJECTIVE: To investigate the distribution of hepatitis C virus (HCV) subtypes among intravenous drug users (IDUs) in Kunming, Yunnan province, in 2014. METHODS: A total of 276 plasma samples were collected from IDUs in Kunming during April 2014 -July 2014, in which 199 plasma samples were tested to be HCV antibody positive. For the HCV antibody positive samples, HCV E1E2 genes and NS5B genes were amplified by using nested-polymerase chain reaction (PCR). After sequencing, the HCV subtypes were determined through phylogenetic analysis. RESULTS: Based on the phylogenetic trees of E1E2 gene and NS5B gene fragments, a total of 125 samples were genotyped. 3b was the predominant subtype (48.8%,61/125), followed by 3a (30.4%, 38/125), 6n (14.4%, 18/125), 6a (3.2%, 4/125) and 1b (3.2%, 4/125). The distributions of HCV subtypes by sex, marital status, ethnic group and HIV-1 infection status showed no statistical differences. However, the distribution of HCV subtypes by age showed statistical difference, the diversity of HCV subtypes was found in age group <45 years. The genetic distances of 3a, 3b and 6a on E1E2 and NS5B were larger than those of 1b and 6n. For genotype 3, the genetic distances of 3b on E1E2 and NS5B were larger than those of 3a. CONCLUSION: Five HCV subtypes were found among IDUs in Kunming, HCV subtypes 3b and 3a were predominant, which have circulated in this population for long time.

[A comprehensive surveillance on HIV among 1,237 men who have sex with men in thirteen cities of Yunnan].

OBJECTIVE: To understand the knowledge, risk behaviors and HIV prevalence in men who have sex with men (MSM) in thirteen cities. METHODS: Target samples were chosen using the snowball-rolling method, with transverse KABP and HIV-antibody testing developed for those MSM in thirteen cities of Yunnan. RESULTS: A total of 1237 valid questionnaires and 1129 blood samples were collected. Basic knowledge on HIV and the rate of the response was 93.2%. 81.1% of the respondents had anal sex with male partners in the last six months, of them 49.7% could persistently using condoms in each anal sex episode. 29.0% of the respondents had sex with female partners in the last six months. The HIV prevalence among the studied MSM was 8.2% and the prevalence of syphilis among them was 3.9%. Most risky factors of those MSM infected by HIV would include: not persistently use condom when having sex and co-infection of syphilis. CONCLUSION: Both rates of HIV infection associated risk behaviors and HIV prevalence were high in MSM under study that called for more work on HIV prevention and control MSM in Yunnan.

[A dynamic analysis on incidence and trend of HIV-1 epidemics among intravenous drug users, attendants at the STD clinics and pregnant women in Yunnan province, China].

OBJECTIVE: BED-CEIA assay was used in HIV/AIDS surveillance sentinel sites to identify recent HIV-1 infection, to estimate HIV-1 incidence and to understand the epidemic trends in Yunnan province. METHODS: Serum specimens were collected from IDUs in sentinel sites, attendants in STD clinics and pregnant women under a cross sectional study from 2000 to 2007. Specimens confirmed as HIV-1 positive were tested with BED-CEIA to find recent HIV-1 infection, then the annual HIV-1 incidence for each group was calculated and the trends of HIV-1 incidence observed. RESULTS: 144 780 serum specimens were collected and 4932 of them were confirmed as HIV-1 positive. 4678 positive specimens were tested with BED-CEIA and 723 ont of them were identified as recent infections. Specimens from the two years were combined for testing. The average HIV-1 prevalence among IDUs was 18.2% - 26.9% from 2000 to 2007 and the annual incidence were 14.65%, 6.21%, 4.06%, 2.23% respectively. The average HIV-1 prevalence among attendants in STD clinics was 1.6% - 3.2% and the annual incidence rates were 1.46%, 0.76%, 0.52%, 0.33% respectively. The average HIV-1 prevalence among pregnant women was 0.2% - 0.5% and the annual incidence rates were 0.16%, 0.11%, 0.10%, 0.09% respectively. CONCLUSION: HIV-1 incidence rates among IDUs, STDs and pregnant women showed a steady decrease.