Domestic animals as potential reservoir hosts of trypanosoma brucei gambiense in sleeping sickness foci in Cameroon

An explanation of the endemic nature and/or the resurgence of Human African Trypanosomiasis (HAT) in the historic foci in West and Central Africa may be the existence of an animal reservoir. In some HAT foci, pigs were found infected by Trypanosoma brucei gambiense but the implication of the other domestic animals was not quite evaluated. This study aims to determine the prevalence of T. fa. gambiense in domestic animal species (goat, sheep, pig and dog) commonly found in the four active HAT foci in Cameroon (Bipindi, Fontem, Campo and Doumé). Blood samples were collected from 307 pigs, 264 goats, 267 sheep and 37 dogs and used for parasitological (QBC), immunological (LiTat 1.3 CATT) and molecular (PCR) analyses. QBC detected trypanosomes in 3.88 % domestic animals while 22.7 % were sero-positive with LiTat 1.3 CATT tests. Of the 875 animals analysed, 174 (19.88 %) harboured T. brucei s.l. DNA, found in each of the four types of animal and in the four localities. The infection rate significantly differed among the animal species (p < 0.0001) and localities (p < 0.0001). The PCR also revealed T. b. gambiense group 1 DNA in 27 (3.08 %) domestic animals. The specific infection rates were as follows: sheep (6.74 %), goats (3.08 %), pigs (0.32 %) and dogs (0 %). T. b. gambiense was found in 8 (3.92 %) animals from Bipindi, 15 (4.83 %) from Campo, 4 (2.59 %) from Fontem-Center and none from Doumé. The infection rates significantly differed between the localities, and correlated with the intensity of HAT transmission in the foci.