Persistent viral infections impact key biological traits in Drosophila melanogaster

Persistent viral infections have been assumed to have minimal fitness costs for insects. Using Drosophila melanogaster , we established persistent mono-infections with four different enteric RNA viruses (Drosophila A virus, Drosophila C virus, Bloomfield virus, and Nora virus) and observed that these infections significantly reduce fly survival, alter the number of viable offspring per female, modulate microbiome composition, and impact locomotor abilities. These results demonstrate significant impacts of persistent viral infections on key biological traits and challenge the assumption of the innocuity of persistent viral infections for the host. In addition, the four viruses displayed different accumulation kinetics and elicited unique transcriptional profiles with no common core responses. The transcriptional changes triggered by DCV infection persisted even after viral clearance. Our findings reveal that persistent viral infections modulate critical aspects of insect biology and can have negative impacts on host physiology and behavior.