Application of antigen-detection enzyme immunoassay for the diagnosis of porcine Trypanosoma brucei infection

The prevalence rate of Trypanosoma brucei infection in pigs was appraised by a monoclonal antibody-based antigen-detection enzyme immunoassay (antigen-ELISA). Blood samples were collected in the abattoir from pigs reared in the rain forest and derived savannah region of Nigeria under the traditional extensive management system. Blood samples were also collected from 50 exotic pigs reared on a commercial farm with fly-proof pens. These blood samples were analyzed for presence of trypanosomes and antigens in peripheral blood. Of 189 porcine blood samples 51 (27.0%) were positive for circulating antigens, whereas only 4 (2.1%) had demonstrable trypanosomes as revealed by the haematocrit centrifugation/buffy-coat technique. When the 51 blood samples collected in EDTA tube corresponding to those sera that were positive for T. brucei antigens were subinoculated into mice, 46 (90.1%), the mice became infected. Demonstration of trypanosomes in the infected mice is supportive proof that the parasites were residing in the infected hosts. Samples collected from 50 exotic pigs in fly-proof pens were all antigenELISA negative. In addition, none of the corresponding 50 control blood samples had demonstrable trypanosomes by the buffy-coat method, nor do they show detectable parasites after subinoculation into mice. Thus, antigen-ELISA appeared to be a better and more useful tool for mass sero-epidemiological survey of porcine T. brucei infection when compared to the buffy-coat technique.