Epidemiology of bovine anaplasmosis and babesiosis in Costa Rica

A serum bank created by the National Brucellosis Control Program during 1991 consisted of approximately 4000 sera collected from farms in each of the seven provinces in Costa Rica. Sera were used to determine the prevalence of antibodies directed against Anaplasma marginale, Babesia bigemina and Babesia bovis in Costa Rica and to study some geographical, ecological and management factors which could influence the epidemiology of the infection. The overall seroprevalence in bovines was 72.4%, 55.4% and 54.1% for A. marginale, B. bigemina and B. bovis, respectively. The Moran's index or spatial autocorrelation coefficient, which tests the significance of geographical patterns in disease distribution, indicated two foci of seropositivity in the country for B. bovis: one located mainly in the dry tropical forest and the other located in the tropical moist forest. Suggested foci were corroborated by a risk assessment using the random effects models.