[Recent data on hemorrhagic fevers in West Africa].

Among the viruses which can provoke human haemorrhagic fevers, the Congo-Crimean Haemorrhagic Fever and Rift Valley Fever viruses have been discovered relatively recently in West Africa. Two human cases of severe haemorrhagic fever have been connected with Congo-CHF, in Mauritania and Burkina-Faso. The epidemiological enquiry performed in Mauritania, consequent to the appearance of the first case, has demonstrated that the patient had been contaminated by contact with camels. Twelve strains of Congo-CHF virus have been isolated from ticks taken on bovines and dromedaries in that area. The serological enquiries realized on man show that the incidence is relatively feeble; on the other hand, among animals, one finds a large distribution among small ruminants in Mauritania as well as in Senegal. The recent realization of a complete identity between the Zinga and Rift Valley Fever viruses has broadened the geographical distribution of this virus to the whole of inter-tropical Africa including Madagascar. The serological enquiries realized among men and animals in areas where the virus has been isolated from wild vectors show that the presence of antibodies is faintly superior. On the other hand, in southern Mauritania, the virus prevails among men, who get antibodies of the IGM type, which proves a recent circulation. The immunological enquiries on camels seem to corroborate these data. The Rift Valley Fever epidemic which broke out in 1978 among the human and animal populations of Egypt has, apparently, been connected with the passage of camels coming from Sudan through the intermediary halting-place of the Assuan dam.(ABSTRACT TRUNCATED AT 250 WORDS)