Examining the Relationship between Urogenital Schistosomiasis and HIV Infection

Abstract

BackgroundUrogenital schistosomiasis, caused by infection with Schistosoma haematobium, is widespread and causes substantial morbidity on the African continent. The infection has been suggested as an unrecognized risk factor for incident HIV infection. Current guidelines recommend preventive chemotherapy, using praziquantel as a public health tool, to avert morbidity due to schistosomiasis. In individuals of reproductive age, urogenital schistosomiasis remains highly prevalent and, likely, underdiagnosed. This comprehensive literature review was undertaken to examine the evidence for a cause-effect relationship between urogenital schistosomiasis and HIV/AIDS. The review aims to support discussions of urogenital schistosomiasis as a neglected yet urgent public health challenge.Methodology/Principal FindingsWe conducted a systematic search of the literature including online databases, clinical guidelines, and current medical textbooks. We describe plausible local and systemic mechanisms by which Schistosoma haematobium infection could increase the risk of HIV acquisition in both women and men. We also detail the effects of S. haematobium infection on the progression and transmissibility of HIV in co-infected individuals. We briefly summarize available evidence on the immunomodulatory effects of chronic schistosomiasis and the implications this might have for populations at high risk of both schistosomiasis and HIV.Conclusions/SignificanceStudies support the hypothesis that urogenital schistosomiasis in women and men constitutes a significant risk factor for HIV acquisition due both to local genital tract and global immunological effects. In those who become HIV-infected, schistosomal co-infection may accelerate HIV disease progression and facilitate viral transmission to sexual partners. Establishing effective prevention strategies using praziquantel, including better definition of treatment age, duration, and frequency of treatment for urogenital schistosomiasis, is an important public health priority. Our findings call attention to this pressing yet neglected public health issue and the potential added benefit of scaling up coverage of schistosomal treatment for populations in whom HIV infection is prevalent.

Schistosomiasis and Human Immunodeficiency Virus in Men in Tanzania

“…26 These findings and ours support the hypothesis that men with urogenital schistosomiasis may more easily transmit HIV to their sexual partners due to tissue inflammation and bleeding, leading to higher concentrations of HIV in the semen of HIVschistosome coinfected men than in HIV-infected men without schistosome infection. 26,27 A recent prospective study demonstrated that men and women with the helminthic infection lymphatic filariasis had a 2-fold increased risk of incident HIV infection compared with those without filariasis. 28 Unlike schistosomiasis, filariasis is not known to have direct effects on the genital tract, suggesting that systemic immune changes induced by filariasis could increase HIV susceptibility.…”

“…To participate in the study, men were asked to provide written informed consent or place their mark on the consent form. [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. Nearly half of the men (328, 48.7%) had had more than one sexual partner in the past 6 months, and the majority of men reported that their sexual partners were typically more than 5 years younger.…”

Schistosoma haematobium in a human immunodeficiency virus-positive patient with cancer of the cervix

“…The question of whether or not genital schistosomiasis might act as a co-factor has also been raised. 4 A few cases have been reported and published. 5,9 However, there is no convincing evidence that schistosomiasis can independently have a carcinogenetic effect without HPV.…”

“…3 Furthermore, schistosomiasis may increase the risk of human immunodeficiency virus (HIV) infection. 4 It has also been postulated that schistosomiasis may be a risk factor for the development of cervical cancer.…”

review of the control of schistosomiasis in South Africa

“…1 Over 800 million people are at the risk of acquiring schistosomiasis in 76 endemic countries, with 46 of these countries in Africa. 2,3 Approximately 207 million people worldwide are infected with schistosomiasis 4 and 85% of the estimated number of infections are in the less developed areas of sub-Saharan Africa. Worldwide, Schistosoma haematobium causes more than half of the schistosomiasis infections, that is, approximately 112 million infections.…”