Epidemiol. Infect. (1997), 118, 35-41 Copyright © 1997 Cambridge University Press
Variations in the prevalence of antibody to brucella infection in cattle by farm, area and district in Kenya
M. KADOHIRA1＊,J. J .MｃDERMOTT1,2,M.M.SHOUKRI1 AND M. N. KYULE2
1Department of Population Medicine, University of Guelph, Guelph, Ontario, NIG 2W1, Canada
2 Department of Public Health, Pharmacology and Toxicology, University of Nairobi, P.O. Box 29053,Nairobi, Kenya
(Accepted 8 July 1996)
SUMMARY
Variations in the sero-prevalence of antibody to brucella infection by cow, farm and area factors were investigated for three contrasting districts in Kenya : Samburu, an arid and pastoral area; Kiambu, a tropical highland area ; and Kilifi, a typical tropical coastal area. Cattle were selected by a two-stage cluster sampling procedure and visited once between August 1991 and 1992.
Schall's algorithm, a statistical model suitable for multi-1evel analysis was used. Using this Model, older age ,free grazing and large herd size ( >31) were associated with higher sero-prevalence. Also, significant farm-to-farm ,area-to-area and district-to-district variations were estimated. The patterns of high risk districts and areas seen were consistent with known animal husbandry and movement risk factors, but the larger than expected farm-to-farm variation within high risk areas and districts could not be explained. Thus, a multi-level method provided additional information beyond conventional analyses of sero-prevalence data.
