Anaplasmosis in Uganda. II. Prevalence of bovine anaplasmosis.

Abstract

The prevalence of bovine anaplasmosis was studied in 320 Zebu cattle randomly selected from three regions of Uganda (central, south-western and north-western) 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 eluated in PBS 0.05% Tween 20 prior to testing at an initial dilution of 1:25. The incidence of parasitaemia ranged from 25% in the central region to 35% in the north-western region and the serological prevalence was lower in the central region and highest in the north-west. Prevalence rates assayed by DOT-ELISA and Western immunoblotting were 1.5-fold greater than those tested with RCAT and 3-fold greater than in CAT. The overall prevalence rates by DOT-ELISA and Western immunoblotting compared favourably with 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 it confirms our observations and those of others that collecting blood on filter papers is a suitable technique for large-scale screening and for seroepidemiological studies.