Interactions Between Glossina Pallidipes Salivary Gland Hypertrophy Virus and Tsetse Endosymbionts in Wild Tsetse Populations

BackgroundTherefore, tsetse control is considered an effective and sustainable tactic for the control of cyclically transmitted trypanosomosis in the absence of effective vaccines and inexpensive, effective drugs. The sterile insect technique (SIT) is currently used to eliminate tsetse fly populations in an area-wide integrated pest management (AW-IPM) context in Senegal. For SIT, tsetse mass-rearing is a major milestone that associated microbes can influence. Tsetse flies can be infected with micro-organisms, including the primary and obligate Wigglesworthia glossinidia, the commensal Sodalis glossinidius, and Wolbachia pipientis. In addition, tsetse populations often carry a pathogenic DNA virus, the Glossina pallidipes Salivary Gland Hypertrophy Virus (GpSGHV) that hinders tsetse fertility and fecundity. Interactions between symbionts and pathogens might affect the performance of the insect host. MethodsIn the present study, we assessed the possible interaction of GpSGHV and tsetse endosymbionts under field conditions to decipher the bidirectional interactions in different Glossina species. We determined the co-infection pattern of GpSGHV and Wolbachia in natural tsetse populations. We further analyzed the interaction of both Wolbachia and GpSGHV infection with Sodalis and Wigglesworthia density using qPCR. ResultsThe results indicated that the co-infection of GpSGHV and Wolbachia was most prevalent in Glossina austeni and Glossina morsitans morsitans, with an explicit significant negative correlation between GpSGHV and Wigglesworthia infection. GpSGHV infection levels of more than 104 were not observed when Wolbachia infection was present at high density (>108.5), suggesting a potential protective role of Wolbachia against GpSGHV. ConclusionThe result indicates that Wolbachia infection might protect tsetse fly against GpSGHV and the interactions between the tsetse host and its associated microbes are dynamic, likely species-specific and significant differences may exist between laboratory and field conditions.