Absence of SARS-CoV-2 Antibodies in Natural Environment Exposure in Sheep in Close Contact with Humans

摘要

Different species can harbor coronavirus, including domestic and wild animals. The Coroviridae family is composed of four genera, including Alphacoronavirus, Betacoronavirus, Gammacoronavirus and Deltacoronavirus. Some domestic animals are susceptible to SARS-CoV-2 in natural and experimental infections. The infection of animals is generally a consequence of close contact with COVID-19 patients. Among domestic animals, SARS-CoV-2 replicates in respiratory ex vivo organ cultures of domestic ruminants. In this context, there is no information about the role sheep can play in the spread of the infection. This study tested the antibody response in 90 serum samples from sheep from the pre-pandemic period and 336 serum samples from sheep from the pandemic period (June 2020 to March 2021). In both cases, the animals were in close contact with a veterinary student community composed of more than 700 members. None of the serum samples analyzed were seroreactive based on an enzyme-linked immunosorbent assay (ELISA) using the receptor-binding domain (RBD) of the spike antigen. In this sense, no statistical difference was observed compared to the pre-pandemic sheep. To the authors’ knowledge, this is the first serosurvey in sheep to detect anti-SARS-CoV-2 antibodies. Future investigations should analyze the epidemiological role of sheep in SARS-CoV-2 infection, including the prevalence of infection.