Infection With the Secondary Tsetse-Endosymbiont Sodalis glossinidius (Enterobacteriales: Enterobacteriaceae) Influences Parasitism in Glossina pallidipes (Diptera: Glossinidae)

The establishment of infection with three Trypanosoma spp (Gruby) (Kinetoplastida: Trypanosomatidae), specifically Trypanosoma brucei brucei (Plimmer and Bradford), T. b. rhodesiense (Stephen and Fatham) and T. congolense (Broden) was evaluated in Glossina pallidipes (Austen) (Diptera: Glossinidae) that either harbored or were uninfected by the endosymbiont Sodalis glossinidius (Dale and Maudlin) (Enterobacteriales: Enterobacteriaceae). Temporal variation of co-infection with T. b. rhodesiense and S. glossinidius was also assessed. The results show that both S. glossinidius infection ( χ 2 = 1.134, df = 2, P  = 0.567) and trypanosome infection rate ( χ 2 = 1.85, df = 2, P  = 0.397) were comparable across the three infection groups. A significant association was observed between the presence of S. glossinidius and concurrent trypanosome infection with T. b. rhodesiense ( P  = 0.0009) and T. congolense ( P  = 0.0074) but not with T. b. brucei ( P  = 0.5491). The time-series experiment revealed a slight decrease in the incidence of S. glossinidius infection with increasing fly age, which may infer a fitness cost associated with Sodalis infection. The present findings contribute to research on the feasibility of S. glossinidius -based paratransgenic approaches in tsetse and trypanosomiasis control, in particular relating to G. pallidipes control.