Seroepidemiology of bovine anaplasmosis and babesiosis in Venezuela.

The serological prevalence of bovine anaplasmosis and babesiosis in the Centro-Occidental region of Venezuela was determined using the indirect fluorescent antibody (IFA) and latex agglutination (LAT) tests. Anaplasma marginale IFA and LAT prevalence rates were 57.7 and 48.6% respectively for cattle of all ages and breeds. The respective prevalence of IFA activity to B. bigemina and B. bovis was 78.2 and 38.8%. The LAT test specific only for Babesia spp. revealed that 61.4% of the animals tested were serologically positive for Babesia parasites. Anaplasma marginale and B. bigemina organisms were detected in peripheral blood smears of 21.1 and 7.5% respectively of cattle surveyed. A longitudinal survey of antibody activity and incidence of parasitaemia for Anaplasma and Babesia infections was conducted in two groups of calves from their birth to seven months of age. The animals generally experienced infections between three and four months of age the period subsequent to decline in colostral antibody levels. Seroepidemiological data are considered in the formulation of proposed vaccination regimens for anaplasmosis and babesiosis.