Trypanosomes of the Group: Phylogeny and New Potential Vectors.

Trypanosomes belonging to group are mammalian blood parasites with keds and horse fly vectors. Our aim is to study to vector specificity of trypanosomes. During our bloodsucking Diptera survey, we found a surprisingly high prevalence of trypanosomes in mosquitoes (154/4051). Using PCR and gut dissections, we detected trypanosomes of group mainly in mosquitoes, with the highest prevalence in (22%), (21%), and (10%). Moreover, group were found in keds and blackflies, which were reported as potential vectors for the first time. The vectorial capacity was confirmed by experimental infections of using our isolates from mosquitoes; sand fly supported the development of trypanosomes as well. Infection rates were high in both vectors (47-91% in mosquitoes, 65% in sandflies). Furthermore, metacyclic stages of trypanosomes were observed in the gut of infected vectors; these putative infectious forms were found in the urine of after a second bloodmeal. On the contrary, was refractory to experimental infections. According to a phylogenetic analysis of the 18S rRNA gene, our trypanosomes belong into three lineages, TthI, ThII, and a lineage referred to as here a putative lineage TthIII. The TthI lineage is transmitted by Brachycera, while TthII and ThIII include trypanosomes from Nematocera. In conclusion, we show that trypanosomes have a wide range of potential dipteran vectors, and mosquitoes and, possibly, sandflies serve as important vectors.