Pig trypanosomosis: prevalence and significance in the endemic Middle Belt zone of southern Nigeria.

Abattoir and field/market surveys of 1,954 crossbred pigs aged 6 to 30 months, for trypanosomosis in the Middle Belt zone of Southern Nigeria, revealed a 26.8 infection rate. Of those infected, 66.5, 23.9 and 8.2 % were due to mixed, single Trypanosoma brucei and T. congolense infections respectively. Although 1.5 % of the infections were unidentified, there was no evidence of T simiae. The infection rate was significantly higher (p < 0.05) among the abattoir pigs (37.8 %) than among the farm pigs (21.8 %) in both sexes. Peak infection was noted among pigs aged 11 to 15 months and during the end of the rainy season and the beginning of the dry season (September to December). Complementary mice inoculation tests revealed 83 subpatent and prepatent cases and are being recommended as a confirmatory diagnostic technique. The disease poses problems for pig productivity and the cooperation of scientists is essential.