HIV-1 and HIV-2 seropositivity among female sex workers in the Tenere Desert, Niger

Following an outbreak of falciparum malaria in Bilma, Niger in 1993, an investigation was planned. Because of the Touareg rebellion in the north of the country, it was not possible to reach the area until February 1995. About 10000 Kanouris and Toubbous (this last ethnic group lives mainly in the Tibesti region of northern Chad) live around the Bilma oasis. Traditional trade is their main occupation. Every year, camel caravans travel about 1500 km through the Tenere desert, relying on brackish water holes, to bring salt and dates to either Tibesti or the Air mountains and even as far as the Touareg areas. According to information collected by the local health service, many lorries from Libya go via Dirkou on their way to Nigeria to pass through the American blockade. Dirkou serves as a military check point when entering Niger from the north. Several tracks go through Dirkou from Djanet in Algeria, from Al-Katrun in Libya, and from Zouar in Chad (Figure) At the start of this study, local health workers and traditional authorities gathered the female sex workers in the palm grove to obtain their consent; 122 of the sex workers (average age 25 years) were examined in Dirkou. Refrigerated blood samples were transported to Niamey by air, where they were examined at the National Hospital Laboratory, using the following tests for HIV: Genelaviamixt, Vironostika and Multi-spot HIV 1-2. The results revealed a 27.9% rate of HIV-1 infection (34 /122) and, in 7 cases, co-infection with HIV-1 and HIV-2 (unconfirmed by Western blotting). Half of the sex workers were natives of Niger; the others came from elsewhere in West Africa, both English-speaking and French-speaking countries. It was not possible to sample the contacts, either soldiers or settled inhabitants, through lack of time; counselling was given in the military camp. The only study of HIV seroprevalence among the Touareg population reported a rate of 0.2%. Our study does not support the view that desert zones are at low risk for HIV transmission, even though the situation is worse in non-desert regions of West Africa. The spread of HIV in the nomadic populations constitutes a real public health problem.