Sexually transmitted diseases increase the probability for HIV transmission, presumably through lesions in the genital mucosa. Female genital schistosomiasis, a special form of urinary schistosomiasis due to infection with Schistosoma haematobium, may be another risk-factor for transmission of HIV. From published data there seem to be pathophysiological, immunological and epidemiological evidence for an association between genital ulcer disease due to S. haematobium and HIV-infection in women. Female genital schistosomiasis could be seen as an example of how an interaction between a parasitic disease and HIV facilitates the propagation of the latter. As long as the prevalence of HIV is low in the general population, interventions targeted to high risk groups will significantly delay, or even prevent, widespread dissemination of the HIV infection in the rest of the population. If female genital schistosomiasis is a risk factor for the spread of HIV like other genital ulcer diseases, there should be interesting ways to intervene from the public health point of view.
PIP: Recent epidemiologic, immunologic, and pathophysiologic data suggest that female genital schistosomiasis, a special form of urinary schistosomiasis due to infection with the trematode Schistosoma haematobium, may be a risk factor for human immunodeficiency virus (HIV) in the 44 African countries where these infections coexist. Eggs of the parasite are found in the organs of the female genital tract (vagina, vulva, and cervix), as well as in urine. Epidemiologists have estimated that 90 million Africans are infected with S. haematobium and that 35-100% of so infected women of childbearing age suffer intermittently from genital lesions caused by eggs sequestered within the epithelium. Lesions associated with this disease tend to be multiple and bleed easily, spontaneously or on contact. Women heavily infected with S. haematobium or S. mansoni show a decrease in the number of circulating CD4+ T cells and NK cells; moreover, a cross-reactivity between HIV-1 virion infectivity factor and a surface antigen to S mansoni has been shown. The eroded, friable epithelium of women with genital schistosomiasis provides HIV with access to deeper cell layers; moreover, the abundance of CD4+ cells and macrophages within the confines of the granuloma makes rapid binding of HIV more likely than is the case with other sexually transmitted diseases. The greatest increase in HIV prevalence in the past decade has occurred in Uganda, Kenya, Malawi, and the Central African Republic--countries with S. haematobium rates of about 70%. In addition, the HIV prevalence rate in areas highly endemic for this parasite is 1.2-1.7 times greater in women than men. Needed, to confirm this association, are correlation studies of increases in HIV prevalence over time in women 15-30 years of age and rates of genital schistosomiasis.