Comparison of the susceptibility of different Glossina species to simple and mixed infections with Trypanosoma (Nannomonas) congolense savannah and riverine forest types

Abstract

Teneral Glossina morsitans mositans, G.m.submorsitans, G.palpalis gambiensis and G.tachinoides were allowed to feed on rabbits infected with Trypanosoma congolense savannah type or on mice infected with T.congolense riverine-forest type. The four tsetse species and subspecies were also infected simultaneously in vitro on the blood of mice infected with the two clones of T.congolense via a silicone membrane. The infected tsetse were maintained on rabbits and from the day 25 after the infective feed, the surviving tsetse were dissected in order to determine the infection rates. Results showed higher mature infection rates in morsitans-group tsetse flies than in palpalis-group tsetse flies when infected with the savannah type of T.congolense. In contrast, infection rates with the riverine-forest type of T.congolense were lower, and fewer flies showed full development cycle. The intrinsec vectorial capacity of G.m.submorsitans for the two T.congolense types was the highest, whereas the intrinsic vectorial capacity of G.p.gambiensis for the Savannah type and G.m.morsitans for the riverine-forest type were the lowest. Among all tsetse which were infected simultaneously with the two types of T.congolense, the polymerase chain reaction detected only five flies which had both trypanosome taxa in the midgut and the proboscis. All the other infections were attributable to the savannah type. The differences in the gut of different Glossina species and subspecies allowing these two sub-groups of T.congolense to survive better and undergo the complete developmental cycle more readily in some species than other are discussed.

Spatio-temporal distribution of tsetse and other biting flies in the Mouhoun River basin, Burkina Faso

“…Riverine species have indeed been reported to show lower vectorial competence for T. congolense than for T. vivax (Reifenberg et al, 1997;Solano et al, 2001). The shorter development period of T. vivax (≈10 days), in comparison with those of T. congolense (≈14 days) and T. brucei (≈30 days), also favours T. vivax in disturbed landscapes in which tsetse lifespan is reduced (Van den Bossche et al, 2010).…”

Inhibition of the DNA amplification of trypanosomes present in tsetse flies midguts: implications for the identification of trypanosome species in wild tsetse flies

“…W e observed that the amplification reaction only failed with the midgut samples. Such failure o f PCR in iden tifying parasitologically positive midguts had already been reported (Masiga et al, 1992;Masiga et al, 1996;W oolhouse et al, 1996;Reifenberg et al, 1997;Lefrançois et a l., 1999). PCR lack o f sensitivity cannot be incri minated since raising the quantity o f parasite DNA used proved unsuccessful.…”

Identification of midgut proteins that are differentially expressed in trypanosome-susceptible and normal tsetse flies (Glossina morsitans morsitans)

“…Tsetse flies demonstrate substantial species restriction towards establishment of trypanosome infections in the midgut (Reifenberg et al, 1997). Successful establishment involves midgut factors that are thought to mediate parasite transformation, growth and survival.…”