Abstract

In 2002, a yellow fever (YF) outbreak occurred in the regions of Diourbel and Fatick, centre of Senegal. The index case was a young woman without any history of vaccination. Immunoglobulin M (IgM) specific of YF was detected in her blood by the Centre de Référence OMS sur la Recherche des Arbovirus et des Fièvres Hémorragiques (CRORA) in the Institut Pasteur of Dakar. According to specific case definitions, both active (investigation) and passive detection (surveillance) of human cases were performed and completed by entomological surveys. From September to December 2002, a total of 35 individuals recently infected by YF were identified out of 379 blood samples collected. During the investigation in October, 23 confirmed cases of YF were detected, including 11 deaths. All entomological indexes (Breteau, Container, House) were above the threshold of epidemic risk and 2 YF virus strains were isolated from Aedes furcifer collected in a village where YF cases and death were reported. Mass vaccination campaigns were urgently organized in all districts with positive cases to protect the populations.

Key words: Yellow fever, outbreak, mass vaccination, Senegal, West Africa, arbovirosis.