| variations in the prevalence of antibody to brucella infection in cattle by farm, area and district in kenya. | 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-level analysis was used. using this model, older age, free ... | 1997 | 9042033 |