Anaplasmosis in Uganda. II. Prevalence of bovine anaplasmosis in Uganda

The prevalence of bovine anaplasmosis was studied in 320 Zebu cattle randomly selected from three regions of Uganda: (Central, Southwestern and Northwestern) using dot-ELISA, Western immunoblotting, rapid card agglutination test (RCAT), capillary tube agglutination test (CAT), complement fixation test (CFT), and parasitological techniques. Dried blood on Whatman filter paper No. 1 was eluted in PBS 0.05% Tween 20 prior to testing at an initial dilution of 1:25. The prevalences of parasitaemia were 25% in the central region, 28% in the southwestern region, and 35% in the northwestern region, and the serological prevalence was lowest in the central region and highest in the northwest. Overall, prevalence rates obtained by dot-ELISA (61.9%) and Western immunoblotting (62.5%) were 1.5 times those obtained by RCAT (41%) and three times those obtained by CAT (22.5%). The overall prevalence rates obtained by dot-ELISA and Western immunoblotting compared favourably with the CFT data. The present data utilizing dried blood on filter papers indicate that there is a high prevalence of anaplasmosis in those regions of Uganda surveyed, and confirm our observations and those of others that collecting blood on filter papers is a suitable technique for large scale screening and for seroepidemiological studies.