CRIMEAN-CONGO HAEMORRHAGIC FEVER (CHF) VIRUS IN MAURITANIA.
Crimean-Congo haarmorrhagic fever was diagnosed for the first time in Mauritania in a patient who developed an haemorrhagic syndrome in the Selibaby area (southern Mauritania) in May 1983.
Field investigations included a survey of the prevalence of the virus in ticks an a serological survey on sera collected from man and domestic animal in the different areas of Mauritania.
CCHF virus was isolated from 12/98 pools of Hyalomma marginatum rufipes and 1/22 pools of Hyalomma impeltatum. In contrast no virus was isolated from Hyalomma dromedarii (206 pools tested).
A total of 1,074 sera from goats, sheep and cattle were tested by immunofluorescence antibody assay. High prevalences of antibodies to CCHF virus were detected in several areas of southern Mauritania and the border of Senegal river. Antibodies was also present in 43/80 camels.
In an enzootic area, were found marked differences in the prevalence of antibodies according to the different herds e. g. in Mederdra area, on 17 herds tested, only seven had a high prevalence of antibodies and ten were negative.
It was concluded that the distribution of CCHF virus fits the one of H. marginatum rufipes. During the camel migration from the CCHF foci in southern Mauritania to the north, the H. marginatum rufipes leave their hosts and fall round in an unsuitable environment that does not allow the possibility of a development cycle. In the north (semi-desertic area), H. marginatum rufipes is replaced by H. dromedarii as the dominant species on ungulates. H. dromedarii seeming not be a vector of the CCHF virus, we can postulate on the absence of the virus in this area. But in this part of Africa the true role of H. impeltatum and H. truncatum in the epidemiology of the Crimean-Congo haemorrhagic fever remains to be ascertained.
A serological survey in man in a rural area in southern Mauritania showed that 10/181 (5.5 %) were positive or CCHF virus.
Our data are discussed with compiled informations on the current status of H. marginatum rufipes, H. dromedarii and H. impeltatum distribution in Africa and with CCHF cases reported.