Seroprevalence of anti-SARS-CoV-2 antibodies in household domestic ferrets (Mustela putorius furo) in Spain, 2019-2023

Presence of anti-SARS-CoV-2 antibodies in European bison (Bison bonasus) in Poland, 2019-2023

BACKGROUND

The origin of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains unknown. However, it is likely that the virus spillover occurred from an animal reservoir to humans. Identifying animal species susceptible to SARS-CoV-2 is crucial for understanding cross-species transmission to humans. This study distinguishes itself by focusing on the susceptibility of the European bison (Bison bonasus), an endangered species, to SARS-CoV-2. The objective of this study was to investigate the occurrence of SARS-CoV-2 antibodies in a substantial number (n = 238) of both free-living and captive Polish European bison using an in-house ELISA method and virus neutralization test (VNT).

RESULTS

The seroprevalence of SARS-CoV-2 infection was found to be 1.29% (3/232). None of the seropositive European bison tested positive in the virus neutralization test. All seropositive animals were part of captive herds.

CONCLUSIONS

This study represents the first report of SARS-CoV-2 seroprevalence in both free-ranging and captive European bison in Poland. Based on these findings, the European bison appears to be a less susceptible species to SARS-CoV-2. The most probable route of transmission was from humans to European bison, as all seropositive animals belonged to captive herds with contact with indirect human sources, such as tourists and keepers.

Assessment of SARS-CoV-2 exposure in exotic pets in Spain

Evidence of SARS-CoV-2 infections in different animal species raises concerns about the potential for animal reservoirs and transmission to humans. Here, we evaluate the exposure of exotic pet species to this virus throughout the early years of the pandemic (2020 - 2022) in southern Spain. A total of 180 exotic pets (126 domestic rabbits, 31 ferrets, and 23 rodents) were analyzed for antibodies against SARS-CoV-2 using two different ELISAs. ELISA-positive sera were subsequently tested for specific neutralizing antibodies (nAbs) using the virus neutralization test (VNT). Only one brown rat (Rattus norvegicus), representing 0.6 % of the total, tested positive by ELISA, yet showed negative result for SARS-CoV-2 nAbs by VNT. Our results suggest a very limited risk of SARS-CoV-2 transmission among humans and sympatric exotic pet species in the study region. However, the virus's potential for interspecies transmission emphasizes the need for ongoing surveillance, especially in settings with frequent human-animal interactions, to avoid potential virus evolution, the emergence of new animal reservoirs, and spillover events.

Molecular and Serological Studies on Potential SARS-CoV-2 Infection among 43 Lemurs under Human Care-Evidence for Past Infection in at Least One Individual

In the setting of the recent COVID-19 pandemic, transmission of SARS-CoV-2 to animals has been reported in both domestic and wild animals and is a matter of concern. Given the genetic and functional similarities to humans, non-human primates merit particular attention. In the case of lemurs, generally considered endangered, they are believed to be susceptible to SARS-CoV-2 infection. We have conducted a study for evidence of SARS-CoV-2 infection among the 43 lemurs of Mundomar, a zoological park in Benidorm, Spain. They belong to two endangered lemur species, 23 black-and-white ruffed lemurs (Varecia variegata) and 20 ring-tailed lemurs (Lemur catta). Health assessments conducted in 2022 and 2023 included molecular analyses for SARS-CoV-2 RNA of oral and rectal swabs using two different RT-qPCR assays, always with negative results for SARS-CoV-2 in all animals. The assessment also included serological testing for antibodies against the receptor-binding domain (RBD) of the spike protein (S) of SARS-CoV-2, which again yielded negative results in all animals except one black-and-white ruffed lemur, supporting prior infection of that animal with SARS-CoV-2. Our data, while not indicating a high susceptibility of lemurs to SARS-CoV-2 infection, show that they can be infected, adding to the existing information body on potential ways for SARS-CoV-2 virus spreading in zoos, highlighting the need for animal surveillance for the virus.