Risk of transmission of sleeping sickness in the four historical epicentre villages of the Bipindi focus, Cameroon.

BACKGROUND

Bipindi is a historic focus of human African trypanosomiasis (HAT). With the number of cases declining to near-elimination levels, understanding the current entomological risk is crucial to guiding elimination strategies.

METHODS

Two entomological surveys in four historical sentinel villages used pyramidal traps to capture tsetse flies. Dissected midguts were analyzed by polymerase chain reaction (PCR) for trypanosome infection. Blood meal origins were identified using cytochrome B gene heteroduplex analysis.

RESULTS

Glossina palpalis palpalis was accounted for 99.0% of 708 captured tsetse flies. Apparent density was significantly higher in the dry season (2.11) than in the rainy season (0.89) (P < .0001). Blood meal analysis revealed that these flies fed on pigs (25.0%), humans (16.7%), dogs (12.5%) and goats (8.3%). PCR-based analysis of 371 flies detected Trypanosoma congolense (16.4%), Trypanozoon spp. (8.1%) and Trypanosoma vivax (2.7%). No Trypanosoma brucei gambiense was found, suggesting no transmission risk, despite high vector competence.

CONCLUSIONS

Although no evidence of T. b. gambiense transmission was found in this study, the presence of competent tsetse flies represents a potential danger that could jeopardize current control efforts, underscoring the need for sustained integrated surveillance and vector control to achieve elimination.