Animal Reservoirs of Trypanosoma Brucei Gambiense around the Old Gboko Sleeping Sickness Focus in Nigeria

Abstract

The exact role of animal reservoirs in the epidemiology of Trypanosoma brucei gambiense, a parasite ravaging affected rural parts of sub-Saharan Africa, still remains unclear. However, the existence of the parasite in animals is well documented in other parts of Africa. A randomised cross sectional study was conducted in an old sleeping sickness focus in Nigeria by screening 600 cattle and 600 pigs using the card agglutination test for trypanosomosis (CATT) and identifying trypanosomes using ITS 1 and TgsGP PCRs. Data generated were analysed using the Chi square test and odds ratio at 95% confidence interval. The overall infection rates for the CATT and TgsGP-PCR were 8.9 and 0.9%, respectively which varied significantly between cattle (7.2%) and pigs (10.7%) with the CATT. The CATT based infection rates in relation to study sites, breeds and management practices varied significantly (p < 0.05) between 2.0 and 17.0%, while the PCR based ranged between 0 and 1.7%. Trypanosomes of animal origin identified by ITS 1 PCR were T. brucei (4.2%), Trypanosoma congolense forest (3.2%), T. congolense savannah (2.0%), Trypanosoma vivax (2.2%) and mixed infections (1.5%) in cattle as well as T. brucei (4.8%), T. congolense forest (1.8%), T. congolense savannah (1.0%) and mixed infections (1.2%) in pigs. T. brucei gambiense and other animal trypanosomes were identified among animals in the focus, indicating the existence of animal reservoirs of human infective T. b. gambiense. This suggests that the inclusion of reservoir control component in T. b. gambiense control programmes will help in the control of this parasite in this focus.