Chikungunya disease is generally recognized in Africa by serosurveys conduc
ted in rural areas. Epidemics are rarely documented. We report two outbreak
s in Senegal: one having occurred near Kaffrine in 1996 during an epidemic
of yellow fever (YF), the second in Niakhar in 1997. Both diagnoses were co
nducted by IgM antibodies captures and confirmed by virus isolations.
In Kaffrine, a randomised study was carried out on 447 blood donors whose s
erum was systematically tested for the most frequently encountered arboviru
ses in Senegal. The incidence rate was higher for the unrecognized Chikungu
nya infection (35,3%) than for the notified YF infection (21%).
In Niakhar; Chikungunya infection was initially detected through three case
s having occurred in health workers. A serosurvey was then conducted to def
ine the area of prevalence.
We report the clinical forms of Chikungunya virus infections the interest i
ii detecting IgM for recent arbovirus infections and the duration of these
IgM. The difficulties of diagnosis of Chikungunya infection in malaria ende
mic areas are stressed The occurrence of arbovirus infections Yellow fever
and Chikungunya viruses, transmitted by the same vectors (Aedes aegypti) in
Kaffrine are also discussed.