Neglected tropical diseases

Statement – WHO Working Group on Urogenital Schistosomiasis and HIV Transmission, 1–2 October 2009

30 October 09 | Geneva

A Working Group convened by the World Health Organization (WHO) has recommended that schistosomiasis haematobia should henceforth be referred to as urogenital schistosomiasis, a term currently in use in francophone scientific literature.

The meeting was convened to assess the likelihood that schistosomiasis treatment programmes could contribute to HIV control by preventing chronic inflammation and damage to the genital epithelium which may increase susceptibility to HIV.

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In women, the clinical picture of urogenital schistosomiasis may present with a range of signs and symptoms including lesions of the cervix and vagina, vaginal bleeding, pain during sexual intercourse and nodules in the vulva. There may also be long-term irreversible consequences, including infertility. Up to 75% of women in areas endemic for urogenital schistosomiasis may have female genital schistosomiasis (FGS). As many as 45 million women, mainly in rural sub-Saharan Africa, are likely to be affected. Urogenital schistosomiasis also affects men, inducing pathology of the seminal vesicles, prostate and other genital organs.

Urogenital schistosomiasis is a lifetime disease acquired primarily in childhood by exposure to Schistosoma haematobium, one of the two main schistosomes transmitted in Africa. Approximately 120 million people in Africa alone are infected by S.haematobium with associated pathology in the urinary and genital tract.

“… whenever women develop genital schistosomiasis, particular lesions develop in the vagina and in the cervix and the type of the lesions make the epithelium very thin … and vulnerable … and therefore, agents of sexually transmitted diseases particularly HIV can more easily penetrate the epithelium …”.

Dr. Hermann Feldmeier, Professor of Tropical Medicine, Institute of Microbiology and Hygiene, Campus Benjamin Franklin, Charité University Medicine Berlin, Germany

It is well documented that the irreversible pathology caused by schistosomiasis that occurs in adulthood can be effectively prevented by early treatment in childhood. Three treatments with praziquantel during the primary school years reduce bladder pathology at a later age to almost zero. Even a single treatment given in childhood prevents half of the cases of female genital schistosomiasis.

Resolution 54.19 of the World Health Assembly, WHO's governing body, recommends that Member States regularly treat all at-risk school-aged children with single-dose drugs against schistosomiasis and soil-transmitted helminth infections. Regular treatment with praziquantel in childhood is known to have a curative as well as a preventive effect on urogenital schistosomiasis. Praziquantel is also safe in pregnancy and can therefore be given to girls and young women of childbearing age. This treatment costs approximately US$ 0.30 per person, and the Working Group noted with concern that it currently reaches only 5% of those who need it.

There is biological plausibility of a possible link between female genital schistosomiasis and HIV acquisition in women. The Working Group discussed newly emerging evidence for the links between female genital schistosomiasis and HIV and recommended that more studies be carried out in the short and medium-term to fully assess the extent to which control of schistosomiasis could contribute to reducing HIV acquisition in women. It also proposed further clinical studies and identified opportunities to evaluate the impact of schistosomiasis control programmes on the prevention of HIV, in addition to the many other benefits already documented in poor communities in sub-Saharan Africa.

Schistosomiasis website