Susceptibility of Tsetse to Trypanosome Infection in Relation to the Levels of Midgut Trypsin, Trypsinlike Enzymes and Lectins

Abstract

Post feeding midgut trypisn and trypsin-like enzyme levels, trypanosome transformation and infection rates were compared in Glossina morsitans, G. longipennis and G. fuscipes fuscipes. The abilities of midgut homogenates of different tsetse species to agglutinate Trypanosoma brucei was also studied. The results showed that peak enzyme levels in the three Glossina species occurred between 48 and 72 h after feeding, with G. morsitans the lowest. No significant differences were observed among the three species in their abilities to transform T. brucei. Midgut homogenates of G. longipennis and G. fuscipes had greater capacities to agglutinate trypanosomes than that of G. morsitans. Mature T. brucei infection rates in G. longipennis were less than those in G. morsitans and G. fuscipes fuscipes. It was concluded that differences in trypanosome infection rates between the Glossina speicies may be related to levels of blood meal-induced trypsins and lectins. Key words: Glossina spp., trypanosomes trypsin, lectin