Table 4.

Ecological and biological factors influencing the epidemiology trypanosomiasis.

Variable	Ecological/biological factor	Influence/effect
	Vector species	Glossina morsitans morsitans, Glossina brevipalpis
Vector	Intrinsic factors	Increase in vector competence Favorable for survival and reproduction of trypanosomes
	Extrinsic factors	Favorable environment for completion of tsetse life cycle Supportive climate in the valley for survival of vector species
	Relative abundance	Wide choice of feed for vector species Easy choice of alternative feed sources for the vectors
Wildlife	Wide host species	Easy choice of alternative blood-meal options for vectors Extinct species are easily replaced
	Trypanotolerance	Long-term carriers of viable trypanosomes to vectors Increased host competence-tolerance of high infection rates
	Feeding behavior	Nocturnal species synchronized with vector feeding behaviors Diurnal species less favorable by vector species
		Valley temperature favorable for survival of host species
	Climate	Short duration of cold months Rain season favors wide dispersal of host reservoir
Habitat		Valley temperature is favorable for breeding of vector species
	Vegetation	Plant species source feed to wildlife host reservoir Ideal for hibernation of tsetse flies away from the heat
	Riverine	Source of water for host species during dry season Favorable vegetation for survival and hibernation of tsetse flies
	NP	Reduced poaching—increase in host reservoir population High tsetse population density—No eradication programs
Conservation		Expansion of interface—human encroachment
	GMA	Low wildlife population—poaching, human/wildlife conflicts Livestock/humans become alternative sources of blood meal
		Increased risk of human exposure to trypanosomiasis