Outbreak of West Nile virus causing severe neurological involvement in children, Nuba Mountains, Sudan, 2002


Evelyn Depoortere (corresponding author), Justine Kavle and Dominique Legros, Epicentre, 8 rue St Sabin, 75011 Paris, France. Tel.: (+33) 140 21 28 48; Fax: (+33) 140 21 28 03; E-mail: evelyn.depoortere@msf.be,jkavle@jhsph.edu
Kees Keus, Médecins Sans Frontières, M. Euweplein 40, 1001 EA Amsterdam, The Netherlands.
Hervé Zeller and Séverine Murri, Institut Pasteur – UBIVE, 21 avenue T. Garnier, 69365 Lyon, France.


An atypical outbreak of West Nile virus (WNV) occurred in Ngorban County, South Kordophan, Sudan, from May to August 2002. We investigated the epidemic and conducted a case–control study in the village of Limon. Blood samples were obtained for cases and controls. Patients with obvious sequelae underwent cerebrospinal fluid (CSF) sampling as well. We used enzyme-linked immunosorbent assay (ELISA) and neutralization tests for laboratory diagnosis and identified 31 cases with encephalitis, four of whom died. Median age was 36 months. Bivariate analysis did not reveal any significant association with the risk factors investigated. Laboratory analysis confirmed presence of IgM antibodies caused by WNV in eight of 13 cases, indicative of recent viral infection. The unique aspects of the WNW outbreak in Sudan, i.e. disease occurrence solely among children and the clinical domination of encephalitis, involving severe neurological sequelae, demonstrate the continuing evolution of WNV virulence. The spread of such a virus to other countries or continents cannot be excluded.