Ebola virus, transmission

Transmission takes place through direct contact with infected body fluids (including sexual contact) and nosocomially through infected needles and contact with infected blood. Aerogenic transmission of Ebola has been demonstrated in the laboratory in Rhesus monkeys. The natural reservoir of these viruses is unknown. The monkey species which have been studied thus far all die from the infection and therefore cannot form the natural reservoir. Contact with infected monkeys plays a role in the beginning of an epidemic but how these animals are initially infected is not known. The epidemic which started in November 2003 in Mbomo, Congo Brazzaville, was rumoured to have started after villagers found a dead wild pig in the forest and ate its meat. This would be the first case that such an animal would be implicated. Certain fructivorous and insectivorous bats can be experimentally infected and certain species are seropositive in nature. These animals develop an asymptomatic infection. The viral genome has been detected by PCR in certain small rodents in the Central African Republic. These results could not be confirmed. Viral antigens could not be found nor was the virus ever cultured from these animals. The reliability of these PCR results is open to question. Structures, which may well have been viral nucleocapsids, were seen with the electron microscope in spleen cells in some animals. The animals belonged to two genera of rodents (Muridae; Mus setulosus and Praomys sp.) and one species of shrew (Soricidae; Sylvisorex ollula). Probably these leads were red herrings.

Category: Medical Subject Notes , Medicine Notes