This is the first research of STI prevalence included large amounts of new HIV-infected people and detected by blood samples and first-voided urine samples in Yunnan, China. In the present study, a rather high STI prevalence among HIV-positive individuals was confirmed, namely, 47.0% (191/406) in total,45.1% (91/204) in ART-naive individuals and 49.0% (99/202) in ART individuals. This prevalence is much higher than the 5.3% observed in the HIV-positive individuals in Nepal [19], the 11.1% detected in the women living with HIV/AIDS (WLHA) in Uganda [20] and the 23.5% of HIV-infected MSM in China [21], but the prevalence was less than the 60.6% of female sex workers in Peru [22] and the 60.5% of HIV-infected Women in Zimbabwe [23]. The prevalence of genital tract discomfort was 0.5% (2/406),which was rather lower than the STI prevalence. It was interesting to find that HIV-positive individuals tend to neglect or maybe hide their genital tract discomfort. However, our health policy was that no symptom means no screening, those reason may contribute to the high prevalence of STIs. In this study, We found that the overall prevalence of STIs among ART individuals was slightly higher than among ART-naive individuals, although the difference was not statistically significant. This may be associated with the high prevalence of HSV-2/HIV coinfection, 29.4% (60/204) in the ART-naive group versus 37.1% (75/202) in the ART group. In HIV-positive individuals, genital herpes tends to recurrently attack, some individuals even show asymptomatic [24], without intervention, HSV-2 infection will be persisted, accumulated, and transmitted in the people living with HIV/AIDS. However, the ART-naive group had a higher diversity of STIs, coinfections and more sexual partners, and the prevalence of CT, NG and MG was also higher in this study, we believe that ART-naive individuals may face greater threats of STIs and keep in a more dangerous situation.
HSV-2 was the most common STI detected, with an overall prevalence of 33.2% (135/406 ) for HIV-positive individuals in this study. The prevalence of HSV-2/HIV coinfection was much higher than the 6%-13% observed in non-injecting drug users [25], but the prevalence was less than the 48.6% of HIV-positive men who have sex with men (MSM) in Shenyang [26]. Active syphilis was also the familiar STI observed, with the prevalence of 11.8% (24/204) for the ART-naive group and 11.4% (23/202) for the ART group. The result is similar to the 11.3% detected in HIV-positive MSM in Zhejiang province [27], however, the prevalence of active syphilis detected in our study was lesser than the 34.3% of HIV-Positive MSM in Shenyang and 82.9% of HIV-Positive MSM in the United States [26, 28]. HSV-2 and TP can induce genital ulceration, which plays an important role in facilitating the acquisition and transmission of HIV and other STIs.Evidence shows that 60.7% of HSV-2, 3.9% of TP could be detected in ulcer specimens, and 68% of HSV-positive participants were coinfected with HIV in South Africa [29]. Moreover,among genital ulcer disease people, the positivity rate of HSV,TP and HIV was 38.5%,16.0% and 52.2% in Zimbabwe [30].
The prevalence of CT detected in the two groups of participants (3.4% vs 3.0%) was larger than the 0.9% identified in WLHA [20], while it was smaller than the 11.1% of MSM in Port-au-Prince [31]. The prevalence of NG identified in our study (3.4% vs 0.5%) was lower than the 5.4% observed in WLHA [20] and the 7.2% of HIV-positive MSM in Birmingham [32].
Very few researches of M. genitalium prevalence are assessed and generally associated with specific groups of women [33]. Our study provides the first report of MG prevalence among ART-naive individuals in Yunnan. We identified a prevalence of 6.4% (13/204) of MG infection in ART-naive participants. This prevalence was higher than the 2.4% detected in the HIV-infected women in Brazil [34], but the prevalence was lower than the 10.5% of HIV-Positive women in Zimbabwean [35]. However, more and more evidence shows an association between MG and HIV infection. The report shows that the prevalence of MG was comparable to that for CT, NG and HSV among HIV-positive men and MG infection may associate with HIV shedding in the genital tract [35]. MG infection was 21.4% among HIV-infected pregnant women and was associated with higher plasma HIV levels [36]. This finding was notable that the prevalence of MG infection in ART-naive participants was 6.4%, which was higher than CT or NG infection in the two groups. Therefore, we need further researches to understand MG infection in the HIV-positive population in Yunnan province.
We found that ART-naive individuals had a higher unemployment rate, unmarried rate, more sexual partners per year and less use of condoms compared to ART individuals. Unemployment and low income make marry become impractical in China and individuals are more likely to proceed with unprotected sexual behavior for economic gains. However, ART individuals had recognized their condition and more convenient to access STI preventative information. Our result shows that the proportion of ever-injected drugs in the ART-naive group was lower than in another group because the sexual transmission has become the dominant route of HIV transmission, with the government's strict control of drugs, intravenous drug users will be rare. The average count of CD4+ T cells, total T lymphocytes, CD4/CD8, lymphocyte count and percentage of lymphocytes in ART-naive participants were significantly lower than ART participants. In China, the enrolment criteria for ART changed that individuals should receive ART once diagnosed as HIV-positive from 2015. ART can restrain the replication of HIV-1 and gradual recovery of CD4+ T-cell counts [37]. We found the significant promotion of CD4+ T cells and lymphocytes in the ART group. ART participants had a higher average count of white cell, platelet and triglyceride, but a lower average count of erythrocyte and trioxypurine. Lipid abnormalities and metabolic complications associated with ART maybe can explain it [38, 39].
Our findings revealed that females were more likely to have one of the curable STIs (CT, NG, MG, HSV-2 or active syphilis), no matter in the ART-naive group or ART group. Two variables of female and ever-injected drugs showed a significant association with CT-HIV coinfection. Similarly, females and ages >36 years showed association with HSV-2/HIV coinfection. Homosexual or bisexual was associated with a significantly increased MG-HIV coinfection risk. However, age between 18 to 35 years becomes a risk factor in TP-HIV or NG-HIV coinfection. Other risk factors of TP-HIV coinfection were Homosexual or bisexual and NG-HIV coinfection was HIV/HBV coinfection. Participants receiving ART were less likely to have NG-HIV coinfection compared with those not receiving ART. In conclusion, risk factors associated with sexually transmitted infections among HIV-positive individuals were female, age between 18 to 35 years, ever-injected drugs, homosexual or bisexual, HIV/HBV coinfection, and not receiving ART.
Our results on STI-HIV coinfection have important implications for improving STIs screening and treatment services among HIV-positive individuals. Evidence shows that many STIs were asymptomatic.The prevalence of syphilis was 13.5%, among them, 91.3% were asymptomatic among women in China. Most of the anorectal (93.3%) and urethral (79.2%) MG infections were asymptomatic among MSM in western Sydney [15]. A Nigerian study shows that over 95% of STI cases were asymptomatic among MSM [40]. In Yunnan, we found that some hospitals and clinics may not screen other STIs when found a new HIV-positive case, especially in resource-poor settings and rural areas, unless having obvious symptoms. Therefore, strategies to screening all HIV-positive individuals for HSV-2, syphilis, and MG, and so on would be necessary. Untreated STIs may facilitate HIV acquisition and transmission and reduce the effectiveness of antiviral therapy.
There are several limitations to the research. This was a cross-sectional study and the participants were not random. Our collected information might have been compromised by recall bias and social desirability bias as sexual behavior is private information to participants.