Taken together with our observation from the midgut TEM and TUNEL studies that the nuclei of the midgut cells in the mutant mosquitoes had an abnormal shape (Fig. 3d, e) and underwent apoptosis and DNA fragmentation (Fig. 4g and Supplementary Fig. 6g), our results here suggest that hyper-infection of arboviruses induces DNA damage in Ago2−/− mutants, and Ago2 disruption impairs DNA repair mechanisms. The gene discussed is AGO2; the disease is infection.