In November 1996 a yellow fever (YF) outbreak occurred near Kaffrine in the
central part of Senegal. Thirty-six deaths were notified, all children und
er lj years of age. The YF diagnosis was confirmed by MAC-ELISA or by virus
isolation. The immune status against YF virus of a sample population of 44
9 individuals was determined, and 31 confirmed cases and 69 asymptomatic ca
ses were reported. Distribution of YF cases and incidence rate decreased wi
th age, while the attack rate was stable in all age groups. Larva indices w
ere high and Aedes aegypti was common in all villages, causing man-to-man t
ransmission. The greatest risk of YF disease was lack of immunity, especial
ly in individuals <20 years of age. The outbreak was rapidly controlled by
an emergency immunization campaign. YF epidemics occurred in Senegal over t
wo consecutive years. The last outbreak reached the main road to Dakar and
the risk of spread to urban areas has increased.