What every veterinarian needs to know about COVID-19 in animals- updates
As the country continues to reopen following the unprecedented and somewhat clumsy shutdown that swept the country (except for 5 states that remained fully open), it seems like a good time to update what we know about SARS-CoV-2, COVID-19, the disease it causes, and animals.
To date, no evidence exists that pets (or other animals) are a threat for disease transmission to humans. However, it is clear that some animals (dogs, cats – even big ones, ferrets, and mink) can contract the disease from significant and persistent contact with infected humans. To date, reports of likely infection in animals include 2 domestic cats, multiple dogs, ferrets in a lab setting, farmed mink, and apparent infection of multiple big cats in a single zoo (2 lions, 2 amur leopards, 2 Malayan tigers).
The majority of these animals had no clinical signs, but were PCR positive and had a history of contact with confirmed positive humans. In fact, the dog that was first presumptive positive for COVID-19 in the USA (the pug in NC), turned out to be negative after all. The recent positive German shepherd in NY did break the glass ceiling for dog infections in the US though. It is worth reiterating that pets do not appear to pose any threat of infection to humans at this time!
People are the main source of infection with SARS-CoV-2 for other people. But, how infectious are they? And when? While we do not know exactly when infected people stop shedding, it does appear from current data that most infected people begin shedding the virus prior to the onset of clinical symptoms and that the peak of shedding occurs sometime early during the course of illness. All of this information should be cautiously interpreted though as the data on which these statements are based utilizes PCR testing results and we all know that PCR does not assess pathogen viability, only the presence of genetic material.
Antibody titers have become the latest and greatest method for assessing one’s risk of infection; however, an elevated titer does not necessarily confer immunity and lack of an elevated titer does not necessarily imply susceptibility to infection. Recent studies have identified SARS-CoV-2 specific T-cells indicating that antibodies may not be the only mechanism by which a person may be protected from infection.
Finally, we come to the newest hippest fashion accessory – the mask. While all the cool kids seem to be sporting them (with personalized patterns, etc.), unfortunately, the efficacy of masks in containing this virus is unknown. In fact, per the CDC, “A cloth face covering may not protect the wearer, but it may keep the wearer from spreading the virus to others.” Please note the use of the operative word, “may.”
References:
https://www.uptodate.com/contents/coronavirus-disease-2019-covid-19-epidemiology-virology-and-prevention#H3392906512