Bison, Elk, and Other Captive Wildlife Species Humoral Immune Responses against SARS-CoV-2.

Simple Summary: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for COVID-19, primarily spreads among humans, but there have been cases of transmission between humans and animals, as well as some instances of animal-to-animal transmission. Several zoos have reported cases of large cats such as tigers and lions, gorillas, and other animal species testing positive for SARS-CoV-2, presumably due to contact with humans. White-tailed deer (WTD) are highly susceptible to SARS-CoV-2 and are prevalent throughout the United States with a high population density. Separately, there is limited research and reporting on the susceptibility of bison, elk, and other wildlife species to SARS-CoV-2. This study determines the SARS-CoV-2 seroprevalence for various captive wildlife, elk, and bison, across different regions in the United States, using several serological tests. The presence of neutralizing antibodies to the virus in cheetahs, gorillas, lions, hippopotamuses, elk, and bison indicates that they are susceptible to SARS-CoV-2 infection. This highlights the importance of continuous monitoring of the prevalence of SARS-CoV-2 antibodies in various species that come into close contact with humans. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for COVID-19, has been found to infect various domestic and wild animal species. In this study, convenience serum samples from 575 bison, 180 elk, and 147 samples from various wildlife species collected between 2020 and 2023 from several regions in the United States were analyzed for the presence of SARS-CoV-2-specific antibodies. Two commercial ELISA assays based on the inhibition of the SARS-CoV-2 receptor-binding domain (sVNT) or the nucleocapsid protein (N-ELISA) of SARS-CoV-2 were used. Positive samples from the sVNT were additionally evaluated using a conventional virus neutralization test (VNT). Our results indicated that 1.2% of bison, 2.2% of elk, and 4.1% of the other wildlife species serum samples were seropositive in the sVNT, whereas 4.2% of bison, 3.3% of elk, and 1.4% of the other captive wildlife species serum samples tested positive by the N-ELISA. Among the sVNT serum samples, two samples from bison, one sample from elk, and five serum samples from other wildlife species (one cheetah, one gorilla, two lions, and one hippopotamus) had neutralizing antibody titers in the VNT, indicating these species are susceptible to SARS-CoV-2 infection. These findings highlight the importance of broad surveillance efforts for the effective monitoring of SARS-CoV-2 in non-human hosts. [ABSTRACT FROM AUTHOR]