title: An investigation of a major outbreak of Rift Valley fever in Kenya: 2006-2007.
abstract: 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.
authors.affiliation: Division of Communicable Disease Control, Kenya Ministry of Public Health and Sanitation, Nairobi, Kenya. drnguku@yahoo.com
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Nguku
authors.forename: S K
authors.initials: SK
authors.lastname: Sharif
authors.forename: David
authors.initials: D
authors.lastname: Mutonga
authors.forename: Samuel
authors.initials: S
authors.lastname: Amwayi
authors.forename: Jared
authors.initials: J
authors.lastname: Omolo
authors.forename: Omar
authors.initials: O
authors.lastname: Mohammed
authors.forename: Eileen C
authors.initials: EC
authors.lastname: Farnon
authors.forename: L Hannah
authors.initials: LH
authors.lastname: Gould
authors.forename: Edith
authors.initials: E
authors.lastname: Lederman
authors.forename: Carol
authors.initials: C
authors.lastname: Rao
authors.forename: Rosemary
authors.initials: R
authors.lastname: Sang
authors.forename: David
authors.initials: D
authors.lastname: Schnabel
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Feikin
authors.forename: Allen
authors.initials: A
authors.lastname: Hightower
authors.forename: M Kariuki
authors.initials: MK
authors.lastname: Njenga
authors.forename: Robert F
authors.initials: RF
authors.lastname: Breiman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood; D002648:Child; D002675:Child, Preschool; D002980:Climate; D004196:Disease Outbreaks; D005260:Female; D005544:Forecasting; D006801:Humans; D007630:Kenya / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods; D012295:Rift Valley Fever / Q000453:epidemiology / Q000401:mortality / Q000517:prevention & control / Q000821:virology; D012296:Rift Valley fever virus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D012987:Soil / Q000032:analysis; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D012987:Soil