Tsetse fly saliva: Could it be useful in fly infection when feeding in chronically aparasitemic mammalian hosts.
Abstract
Sleeping sickness and nagana are two important diseases cuased by African trypanosomes in humans and animals
respectively, in tropical african countries. A number of trypanosome species are implicated in these diseases, but it
is the Trypanosoma brucei group that is responsible for the chronic form of sleeping sickness. During the course of
this chronic infection the parasite shows a clear tropism for organs and tissues and only sporadically appears in the
blood stream. Notwithstanding this feature, tsetse flies normally get infected from chronically infected apparasitemic
hosts. For some pathogens like the microfilaria, it has already shown that the saliva of the vector, black fly saliva
contribute to orient the pathogen to the site of the vector bite. Chemotaxis of tsetse saliva may perhaps stimulate
movement of Trypanosoma brucei parasites from tissues to the bloodstream and via the vascular to the tsetse
feeding site, and could explain the relatively high infection rate of tsetse flies feeding on chronically infected
animals. This review paper looks into the possible role of trypanosome-vector saliva in ensuring parasite acquisition
and its application in the tsetse – trypanosome interaction at the host skin interphase.