Demonstration of SARS-CoV-2 Exposure in Korean Native Cattle and Korean Native Black Goats in Korea

SIMPLE SUMMARY: With the global spread of COVID-19, surveillance of companion animals living in close proximity to humans has been conducted due to the zoonotic nature of the causative agent, SARS-CoV-2. However, further research is still needed when it comes to livestock animals, particularly cattle and goats that are raised in grazing management systems as part of a group. In this study, nasal swabs and blood samples were collected from randomly selected Korean native cattle and Korean native black goats across nine different provinces in Korea. Of the 1798 animals tested, we found 1 cattle and 1 goat with detectable SARS-CoV-2 RNA, 54 Korean native cattle (4.60%) and 16 Korean native black goats (2.56%) with antibodies, and 51 Korean native cattle (4.34%) and 14 goats (2.24%) with virus-neutralizing antibodies. Infections have been found in various animals after initiating in wildlife and spreading widely among humans, and our results indicate the presence of antigens and antibodies in Korean native cattle and Korean native black goats. This suggests a potential reverse zoonosis, where humans may be infected through a widespread epidemic. Therefore, continuous monitoring is crucial, and additional testing should be conducted on a broader range of animals. ABSTRACT: The COVID-19 pandemic is caused by the zoonotic SARS-CoV-2 virus. A wide range of animals that interact with humans have been investigated to identify potential infections. As the extent of infection became more apparent, extensive animal monitoring became necessary to assess their susceptibility. This study analyzed nasal swabs and blood samples collected from randomly selected Korean native cattle and Korean native black goats. The tests conducted included real-time qPCR to detect SARS-CoV-2 antigens, an ELISA to detect antibodies, and a plaque reduction neutralization test (PRNT) to determine the presence of neutralizing antibodies. Among the 1798 animals tested (consisting of 1174 Korean native cattle and 624 Korean native black goats), SARS-CoV-2 viral RNA was detected in one Korean native cattle and one Korean native black goat. ELISA testing revealed positive results for antibodies in 54 Korean native cattle (4.60%) and 16 Korean native black goats (2.56%), while PRNTs yielded positive results in 51 Korean native cattle (4.34%) and 14 Korean native black goats (2.24%). The presence of SARS-CoV-2 antigens and/or antibodies was identified in animals on farms where farmworkers were already infected. It is challenging to completely rule out the possibility of reverse zoonotic transmission from humans to livestock in Korea, although the transmission is not to the same extent as it is in highly susceptible animal species like minks, cats, and dogs. This is due to the limited geographical area and the dense, intensive farming practices implemented in these regions. In conclusion, continuous viral circulation between humans and animals is inevitable, necessitating ongoing animal monitoring to ensure public health and safety.