Survey of severe acute respiratory syndrome coronavirus 2 in captive and free-ranging wildlife from Spain

Comparison of Three Commercial ELISA Kits for Detection of Antibodies Against SARS-CoV-2 in Serum Samples from Different Animal Species

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the coronavirus disease 19 (COVID-19) pandemic, significantly impacting global health, economies, and social stability. In February 2020, the first cases of SARS-CoV-2 infections in animals were documented, highlighting the potential risks posed by regular human-animal interactions in facilitating viral transmission. In consequence, it is essential to validate surveillance methods for SARS-CoV-2 in animals. In the present study, 101 sera from different animal species (36 cats, 41 dogs, 4 ferrets, 10 wild boar, 6 domestic goats, and 4 lions) were tested using three different ELISA kits to evaluate humoral responses against SARS-CoV-2. ELISA results were compared and correlated with a pseudovirus neutralization test (pVNT), considered as the reference assay. ELISA-1, targeting the receptor binding domain (RBD) neutralizing antibodies (nAbs) of SARS-CoV-2, exhibited the highest diagnostic performance, and proved to be a reliable tool for initial screenings in high-throughput animal studies. In contrast, ELISA-2 (also targeting RBD nAbs) and ELISA-3 (targeting nucleoprotein antibodies) demonstrated lower sensitivity for detecting seropositive animals.

Intraspecific SARS-CoV-2 Delta variant transmission among red fox (Vulpes vulpes) and striped skunk (Mephitis mephitis)

This study assessed the susceptibility of red fox (Vulpes vulpes) and striped skunks (Mephitis mephitis) to the Delta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Upon finding that both species were susceptible to infection and shed infectious virus, transmission potential was assessed by exposing naïve animals to infected members of their species indirectly (red fox) or directly (striped skunks). Red fox transmitted virus to conspecifics, while contact striped skunks did not become infected with the virus or develop a detectable humoral response. This suggests that red fox could contribute to the maintenance of SARS-CoV-2, while striped skunks are unlikely to do so.