An Investigation of a Major Outbreak of Rift Valley Fever in Kenya: 2006-2007

作者:Nguku Patrick M; Sharif S K; Mutonga David; Amwayi Samuel; Omolo Jared; Mohammed Omar; Farnon Eileen C; Gould L Hannah; Lederman Edith; Rao Carol; Sang Rosemary; Schnabel David; Feikin Daniel R; Hightower Allen; Njenga M Kariuki; Breiman Robert F*
来源:The American Journal of Tropical Medicine and Hygiene, 2010, 83(2): 5-13.
DOI:10.4269/ajtmh.2010.09-0288

摘要

An outbreak of Rift Valley fever (RVF) occurred in Kenya during November 2006 through March 2007. We characterized the magnitude of the outbreak through disease surveillance and serosurveys, and investigated contributing factors to enhance strategies for forecasting to prevent or minimize the impact of future outbreaks. Of 700 suspected cases, 392 met probable or confirmed case definitions; demographic data were available for 340 (87%), including 90 (26.4%) deaths. Male cases were more likely to die than females, Case Fatality Rate Ratio 1.8 (95% Confidence Interval [CI] 1.3-3.8). Serosurveys suggested an attack rate up to 13% of residents in heavily affected areas. Genetic sequencing showed high homology among viruses from this and earlier RVF outbreaks. Case areas were more likely than non-case areas to have soil types that retain surface moisture. The outbreak had a devastatingly high case-fatality rate for hospitalized patients. However, there were up to 180,000 infected mildly ill or asymptomatic people within highly affected areas. Soil type data may add specificity to climate-based forecasting models for RVF.