Association of Schistosomiasis and HIV Infection in Tanzania

Abstract

Abstract. Animal and human studies suggest that Schistosoma mansoni infection may increase risk of human immunodeficiency virus (HIV) acquisition. Therefore, we tested 345 reproductive age women in rural Tanzanian villages near Lake Victoria, where S. mansoni is hyperendemic, for sexually transmitted infections (STIs) and schistosomiasis by circulating anodic antigen (CAA) serum assay. Over one-half (54%) had an active schistosome infection; 6% were HIVseropositive. By univariate analysis, only schistosome infection predicted HIV infection (odds ratio [OR] = 3.9, 95% confidence interval = [1.3-12.0], P = 0.015) and remained significant using multivariate analysis to control for age, STIs, and distance from the lake (OR = 6.2 [1.7-22.9], P = 0.006). HIV prevalence was higher among women with more intense schistosome infections (P = 0.005), and the median schistosome intensity was higher in HIV-infected than -uninfected women (400 versus 15 pg CAA/mL, P = 0.01). This finding suggests that S. mansoni infection may be a modifiable HIV risk factor that places millions of people worldwide at increased risk of HIV acquisition.

Schistosomiasis and Human Immunodeficiency Virus in Men in Tanzania

“…Our prior findings in women with S. mansoni, which preferentially affects the gastrointestinal tract, had led us to a similar hypothesis. 4 Now, based on our finding that schistosomeinfected men do not appear to have increased odds of HIV infection, an alternate hypothesis seems plausible as well. Schistosomiasis may increase the seminal and systemic HIV viral load, thereby increasing HIV transmission from one schistosome-infected individual to another in schistosomeendemic communities.…”

“…We predicted that both genders would experience schistosomeinduced systemic immunomodulation that would increase the odds of HIV infection. We postulated that the reported ORs of 3-4 in women [2][3][4] were higher than would be observed in men, due to schistosome-induced epithelial breaches in the female genital tract that may facilitate HIV viral entry following sexual exposure, for which there would not be a comparable effect in men. We therefore hypothesized that the odds of HIV infection in schistosome-infected men would be increased 2-fold compared with men without schistosome infection, and we conducted interviews and additional testing to control for other factors known to be associated with HIV infection.…”

“…Five of these were lakeside villages near Lake Victoria where S. mansoni is highly endemic, and four were inland villages where S. haematobium is highly endemic (Figure 1). 2,4,5 The study team visited each of the health posts for 1-3 days between April 2014 and February 2016. We recruited a community-based sample of healthy outpatient men aged 18-50 years in each study villages.…”

“…2 Other groups have reported similar results in women, and suggested that parasite-inducted genital tract lesions may permit HIV viral entry. 3 Our additional observation that women with Schistosoma mansoni infection also had an increased prevalence of HIV infection 4 led us to postulate that chronic systemic inflammation caused by schistosome infection may be an additional mechanism of increased HIV risk, since S. mansoni primarily affects the gastrointestinal tract. Therefore, increased susceptibility to HIV infection in individuals with schistosomiasis may be due to generalized systemic immune alterations, and for this reason may affect men in addition to women.…”

Impact of Short-Time Urine Freezing on the Sensitivity of an Established Schistosoma Real-Time PCR Assay

“…Moreover, lesions of the vagina and cervix make females more vulnerable to sexually transmitted diseases, especially to human immunodeficiency virus (HIV). [2][3][4] Therefore, it is critical that the diagnosis of urogenital schistomiaisis be done early using specific and sensitive methods. Urine filtration, the gold standard method has a limited sensitivity in areas of low endemicity or detection of prepatent infections.…”