EXPOSURE OF ADULT ZEBRAFISH (Danio rerio) TO SARS-CoV-2 AT PREDICTED ENVIRONMENTALLY RELEVANT CONCENTRATIONS: OUTSPREADING WARNS ABOUT ECOTOXICOLOGICAL RISKS TO FRESHWATER FISH

Abstract

While the multifaceted social, economic, and public health impacts associated with the COVID 19 pandemic are known, little is known about its effects on non-target aquatic ecosystems and organisms. Thus, we aimed to evaluate the potential ecotoxicity of SARS-CoV-2 lysate protein (SARS.CoV2/SP02.2020.HIAE.Br) in adult zebrafish (Danio rerio) at predicted environmentally relevant concentrations (0.742 and 2.226 pg/L), by 30 days. Although our data did not show locomotor alterations or anxiety-like or/and anxiolytic-like behavior, we noticed that exposure to SARS-CoV-2 negatively affected habituation memory and social aggregation of animals in response to a potential aquatic predator (Geophagus brasiliensis). An increased frequency of erythrocyte nuclear abnormalities was also observed in animals exposed to SARS-CoV-2. Furthermore, our data suggest that such changes were associated with a redox imbalance (↑ROS, ↑H2O2, ↓SOD, and ↓CAT), cholinesterasic effect (↑AChE activity), as well as the induction of an inflammatory immune response (↑NO, ↑IFN-gamma, and ↓IL-10). For some biomarkers, we noticed that the response of the animals to the treatments was not concentration-dependent. However, principal component analysis (PCA) and the “Integrated Biomarker Response” index (IBRv2) indicated a more prominent ecotoxicity of SARS-CoV-2 at 2,226 pg/L. Therefore, our study advances knowledge about the ecotoxicological potential of SARS-CoV-2 and reinforces the presumption that the COVID-19 pandemic has negative implications beyond its economic, social, and public health impacts.