Azoxystrobin (AZ) is one of the most widely used
strobilurin fungicides in the world, and its residue has seriously endangered aquatic ecological security. Our previous data showed that AZ exposure may reduce the resistance of fish to rhabdovirus
infection in aquatic environment. Here, we further reported a potential long-term adverse effect of AZ exposure on the
antiviral and immunosuppressive recovery in fish, and observed that mitochondrial dynamic balance was disturbed by AZ in which excessive mitochondrial fission occurred in response to decreased
ATP levels. When a recovery operation was performed in AZ-exposed cells and fish, infectivity of our model virus, spring viraemia of carp virus (SVCV), was significantly decreased in vitro (using the
epithelioma papulosum cyprini [
EPC] fish cell line) and in vivo (using zebrafish) in a time-dependent manner. Also, the expression of eight innate
antiviral immune genes (IFNs, ISG15, MX1, RIG-I, IRF3, Nrf2 and HO-1) showed a similar change to SVCV replication between the longer exposure period and the expression recovery. Additionally, AZ facilitated horizontal transmission of SVCV in a static cohabitation challenge model, predicting the increase of the potential for the viral outbreak. Therefore, our data suggest that long-term effect of AZ on irreparable impairment in fish made AZ residue potentially greater for ecological risks.