Tsetse fly saliva: Could it be useful in fly infection when feeding in chronically aparasitemic mammalian hosts

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.Key words: Chemotaxis, Other vector saliva proteins, Trypanosome, Tsetse salivary proteins

Enhancing vector refractoriness to trypanosome infection : achievements, challenges and perspectives

With the absence of effective prophylactic vaccines and drugs against African trypanosomosis, control of this group of zoonotic neglected tropical diseases depends the control of the tsetse fly vector. When applied in an area-wide insect pest management approach, the sterile insect technique (SIT) is effective in eliminating single tsetse species from isolated populations. The need to enhance the effectiveness of SIT led to the concept of investigating tsetse-trypanosome interactions by a consortium of researchers in a five-year (2013-2018) Coordinated Research Project (CRP) organized by the Joint Division of FAO/IAEA. The goal of this CRP was to elucidate tsetse-symbiome-pathogen molecular interactions to improve SIT and SIT-compatible interventions for trypanosomoses control by enhancing vector refractoriness. This would allow extension of SIT into areas with potential disease transmission. This paper highlights the CRP's major achievements and discusses the science-based perspectives for successful mitigation or eradication of African trypanosomosis.</p