Background Sexual transmission is the fastest growing route of HIV transmission in China. Methods Cross-sectional study of 737 female sex workers (FSW) in Kaiyuan City, Yunnan Province, China from March-May 2006 to describe risk factors for HIV infection and to determine the commercial sex venues where FSWs were most at risk of being infected with or infecting others with HIV. Results Overall HIV prevalence was 10.3%, but prevalence varied with the sex venue with 25.8% of FSWs working on streets being HIV-positive and none of the FSWs working in night clubs. Adjusted odds ratios (OR) of HIV infection were 9.1 (95% CI: 4.67–17.55) for injection drug use; 3.3 (95% CI: 1.46–7.37) for non-injection illegal drug use; 2.7 (95% CI: 1.25–5.93) for duration of sex work ≥5 years; 2.2 (95% CI: 1.05–4.70) for infection with herpes simplex virus type 2; and 2.0 (95% CI: 1.12–3.47) for working at a higher risk entertainment venue. Although condom use was not a significant risk factor in the overall model, FSWs in lower risk venues who reported consistent use with clients had a 70% reduction in HIV infections (OR: 0.30; 95% CI: 0.12–0.90). Conclusions Illegal drug use, particularly with injection drugs, is the single greatest risk factor for HIV infection among FSWs in Kaiyuan City, China. FSWs working on the street or in temporary sublets, beauty salons or saunas are at particularly high risk for transmitting and being infected with HIV. HIV prevention efforts among FSWs should target illegal drug users and these other subgroups.

Some invasive hymenopteran social insects found new populations with very few reproductive individuals. This is despite the high cost of founder effects for such insects, which generally require heterozygosity at a single locus-the complementary sex determiner, csd-to develop as females. Individuals that are homozygous at csd develop as either infertile or subfertile diploid males or not at all. Furthermore, diploid males replace the female workers that are essential for colony function. Here we document how the Asian honey bee (Apis cerana) overcame the diploid male problem during its invasion of Australia. Natural selection prevented the loss of rare csd alleles due to genetic drift and corrected the skew in allele frequencies caused by founder effects to restore high average heterozygosity. Thus, balancing selection can alleviate the genetic load at csd imposed by severe bottlenecks, and so facilitate invasiveness.

The number and proportion of HIV/AIDS among older adults have increased in recent years. The hot spots showed movement from central to southern China. A focused intervention strategy targeting the older PLWHA is urgently required in China.

Objectives To assess the prevalence and risk factors of HIV among male clients of female sex workers in China. Methods Convenience sampling methods were used to recruit 315 clients using FSW-client and client-client networks. Subjects provided information on socio-demographic characteristics and sexual and drug behavior patterns. Blood samples were collected for HIV testing and urine samples for opiate testing. Results Overall HIV prevalence was 6.0%; among drug users it was 30.8%. 33.7% of respondents reported that they always use condoms in commercial sex and 63.5% that they used a condom in the last commercial sex episode. Drug use (OR: 6.1; 95% CI: 1.7–21.4) and lack of a regular sexual partner (OR: 6.3; 95% CI: 1.8–21.9) were significantly associated with HIV infection. Conclusions Clients of FSWs serve as potential bridges for HIV transmission from the high-risk FSWs to the low-risk general population, making them a key target for intervention. High HIV prevalence rates among clients in Kaiyuan is particularly alarming given their risk behavior patterns including high rates of partner exchange, low condom use rates, and drug using behaviors. Innovative interventions are needed to reduce the risk of HIV among clients and reduce the bridge of transmission to the general population.

BackgroundThe mobility of female sex workers (FSWs) is a factor in the geographic spread of human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs). This study describes FSW mobility patterns in a high risk area of China to identify factors associated with increased mobility, and to study the incidence and prevalence of HIV/STIs in this group.Methods270 FSWs recruited from a baseline cross-sectional study were invited to participate in a one-year monthly follow-up cohort study in Kaiyuan City, Yunnan Province, China from 2006 to 2007. Laboratory tests were conducted for HIV/STIs at baseline, 6 and 12 months.ResultsA total of 117 (43.3%) FSWs moved to another city during the year. Risk factors for increased mobility included being from another city within Yunnan (adjusted hazard ratio [AHR] 1.67, 95% confidence interval [CI] 1.09-2.56), being from outside Yunnan (AHR 1.58, 95% CI 1.04-2.54), and working in lower risk entertainment establishments (AHR 1.55, 95% CI 1.03-2.35). HIV-positive subjects, drug users and FSWs in higher risk venue were less likely to change residence, less likely to use condoms with clients, and earned less per client, but had more working locations and more clients each month.ConclusionsThe least mobile FSWs were from Kaiyuan, worked in higher risk venues, were more likely to use drugs and be HIV-infected. Because FSWs characteristics differ according to the venue at which they work, future prevention work should tailor programs according to venue with a particular focus on FSWs in higher risk venues.

Objectives To estimate the HIV incidence and assess the behavioral, clinical, and quality-of-life risk factors for HIV transmission among serodiscordant couples from Henan Province, China. Methods Between January 2006 and December 2008, initially seronegative spouses were tested for HIV at six month intervals. Retrospectively identified subjects were interviewed through face-to-face questionnaire. Cox proportional-hazards model was used to assess the relationship between risk factors and HIV seroconversion. Results Out of 1927 couples, 84 (4.3%) seroconversions occurred, representing a seroconversion rate of 1.71 per 100 person-years. Seroconversion rates increased over time. Not always using condoms (RR=8.42; 95% CI, 4.83–14.67), sexual activity ≥ 4 times per month (RR=5.24; 95% CI, 2.55–10.77), not switching anti-retroviral treatment regimen (RR=1.99; 95% CI, 0.85–4.65), and a quality of life score <12 on the psychological domain (RR=2.33; 95% CI, 1.21–4.48) were associated with increased risk of seroconversion. Seventy one percent of index spouses were on ART. There was no association between rate of HIV seroconversion and last recorded CD4 cell count level of the index spouse. Conclusions Effective HIV prevention interventions targeting discordant couples should focus on sustaining health education, increasing psychosocial support services, and increasing medication adherence monitoring.

Summary Objectives To analyze the risk factors, particularly sexual behaviors, associated with HIV infection, and to describe the risks for HIV transmission among male injecting drug users (IDUs) in China. Methods A cross-sectional study of 314 IDUs in Yunnan Province was conducted. Information on demographics, HIV serostatus, and sexual and drug-using behaviors was collected. Results HIV prevalence among the study subjects was 59.9%. HIV infection was associated with older age (≥27 years), early drug initiation (at ≤20 years of age), and frequent injection (≥once a day). Thirty-seven percent reported multiple sexual partners. Consistent condom use rates were lowest with regular partners (23.8%), followed by 42.5% with casual partners, and 57.3% with female sex workers. Ninety-eight percent of subjects received high ‘HIV knowledge’ scores. Few of the subjects who needed medical care sought it out. Conclusions Despite awareness of HIV, needle sharing and unprotected sex persist in the population, and the HIV prevalence is high. Further interventions should not only seek to educate but also to reduce high-risk behaviors.

Background The majority of people living with HIV/AIDS in China are unaware of their serostatus, and increasing the utilization of HIV testing may help to control the epidemic. Methods This longitudinal study was conducted among female sex workers (FSWs) in 2 cities in Yunnan Province, China. Participants were surveyed in face-to-face interviews and tested for HIV and STDs. Factors associated with HIV-testing history and HIV-test follow-up were analyzed. Results Of the 1642 study participants, 291 (17.7%) had been previously tested and 868 (52.9%) returned for post-test follow-up. Factors associated with having a previous HIV test included attending the Kaiyuan study (aOR: 4.9, 95% CI: 2.3–10.1), ≥9 years of schooling (aOR: 10.9, 95% CI: 2.6–45.5), <5 clients in the recent week (aOR: 1.7, 95% CI: 1.2–2.3), having a regular sexual partner (aOR: 1.9, 95% CI: 1.4–2.5), illegal drug use history (aOR: 2.2, 95% CI: 1.5–3.1), pelvic pain in the past 12 months (aOR: 1.9, 95% CI: 1.1–3.6), HIV-seropositivity (aOR: 1.8, 95% CI: 1.2–2.8), and high perception of HIV risk (aOR: 1.5, 95% CI: 1.1–2.2). FSWs who had ≥9 years of schooling (aOR: 1.4, 95% CI: 1.1–1.9), had <5 clients in the recent week (aOR: 1.3, 95% CI: 1.1–1.6), or were from another province (aOR: 1.9, 95% CI: 1.4–2.5) or city (aOR: 1.4, 95% CI: 1.1–1.8) were more likely to follow-up. Conclusions The low HIV-testing history and follow-up rates found in this is study is a significant public health problem as many high-risk individuals are not aware of their serostatus. Immediate action needs to be taken to increase the utilization of HIV testing services and notify people of their HIV status.