The analyses detected antibodies directed against Marburg virus in the serum of just one of the 10 species caught, the Egyptian rousette, Rousettus aegyptiacus, (in 29 out of 242 individuals tested). This is a migratory species whose distribution range includes all parts of the African continent situated South of the Tropic of Cancer. The search for viral genome fragments on 283 specimens of R. aegyptiacus showed the liver and spleen of four of them to contain RNA sequences belonging to 3 different Marburg virus genes. Blood serum of three out of the four specimens also contained Marburg virus-specific antibodies. The simultaneous presence of specific antibodies and viral RNA fragments strongly suggested this bat species role as a non-symptom developing carrier of the virus, indicating R. aegyptiacus to be the natural reservoir.
Previous research on Ebola virus showed that human infection comes about through the intermediary of infected great ape carcasses. The viral transmission to primates occurs in the dry season, a period when food resources become increasingly scarce. The great apes then come into competition with bat species for fruit supplies when foraging and can be infected notably by blood or by placental fluid that escapes when bats give birth. The mode of contamination by Marburg virus appears to be different, however. It does not appear to need any intermediary to be pathogenic for humans, as foreseen from data of the latest two epidemic outbreaks. In one outbreak, which raged in the north-east of DRC in 2000, most people infected worked in a goldmine, which turned out to be the refuge for a large colony of Egyptian rousettes. During the second epidemic, in Angola, the first victims were children who had gathered fruit from trees where a large population of this species of fruit bat roosted. Other evidence was the fact that the capture sites chosen for this study were all located near caves harbouring sizeable gr
|Contact: Gregory Flechet|
Institut de Recherche Pour le Dveloppement