Sodalis glossinidius (Enterobacteriaceae) and vectorial competence of Glossina palpalis gambiensis and Glossina morsitans morsitans for Trypanosoma congolense savannah type.

Sodalis glossinidius is an endosymbiont of Glossina palpalis gambiensis and Glossina morsitans morsitans, the vectors of Trypanosoma congolense. The presence of the symbiont was investigated by PCR in Trypanosoma congolense savannah type-infected and noninfected midguts of both fly species, and into the probosces of flies displaying either mature or immature infection, to investigate possible correlation with the vectorial competence of tsetse flies. Sodalis glossinidius was detected in all midguts, infected or not, from both Glossina species. It was also detected in probosces from Glossina palpalis gambiensis flies displaying mature or immature infection, but never in probosces from Glossina morsitans morsitans. These results suggest that, a) there might be no direct correlation between the presence of Sodalis glossinidius and the vectorial competence of Glossina, and b) the symbiont is probably not involved in Trypanosoma congolense savannah type maturation. It could however participate in the establishment process of the parasite.