Researchers from the University of Pennsylvania (USA) have discovered that a cat diagnosed with COVID in September 2021 was infected with the delta variant, which was the one that, at that time and in that area, was circulating among humans.
It is well known that SARS-CoV-2 not only affects humans, but has sometimes jumped from our species to domestic animals , livestock and even wildlife. Cats, in particular, seem to be especially susceptible to contracting COVID , although in many cases they do not develop symptoms and it is unlikely that they can transmit the virus to us. Rather it is the other way around, the sick owner is the one who infects the pet. Between cats there also appears to be low transmission.
Something that could happen if the coronavirus is able to circulate silently among our pets, is the possibility of a dangerous mutation that spreads from house to house through cats and dogs . This is why some researchers are trying to track coronavirus variants in pets. For now, it seems that we should not worry.
Going back to the study published in the journal Viruses , the Pennsylvania cat that was infected with COVID in September of last year, subsequently underwent genomic tests that have indicated that the variant that affected it was the delta. This coincides with the predominant variant at that time in that area.
The discovery confirms that the new variants of COVID, at least up to delta, also reach our pets. The good news is that the results of the study suggest that the coronavirus does not appear to be mutating much in cats.
Of the 4,200 human coronavirus samples that were sequenced in Delaware, Pennsylvania, less than 5% contained the 10 single-nucleotide variants found in the domestic cat sample. Seven of these 10 mutations were silent, meaning they caused no significant changes.
“When we looked at a random sample of human sequences from our geographic area, there was nothing dramatically different about our cat sample,” explains veterinarian Elizabeth Lennon of the University of Pennsylvania who was involved in the research. “So our conclusion was that the cat was not infected by a virus that was somehow very different.”
This is the first study to officially identify a delta variant in domestic cats in the United States. However, while investigating, the scientists learned of another Virginia feline that had been infected with the same AY.3 delta variant a month earlier.
Both cat-derived AY.3 genomes showed few single nucleotide variants compared to human-derived samples, which is a good sign, even though the sample size is tiny.
“Some of these mutations may be enriched in the cat samples; however, a larger data set is needed to draw this conclusion,” the authors write.
The investigation has yielded a curious fact and that is that the nasal swab that was done to the Pennsylvania cat in its day did not identify COVID, but a fecal test did . This could be due to the existence of different physical reservoirs of the virus between different species, or that the animal was tested after the infection had progressed from the nose to the butt.
Some people who get coronavirus test positive in stool an average of more than 11 days after respiratory results fall below detectable levels. For this reason, the researchers highlight the importance of taking samples in different parts of the body, since if they had only kept the result of the swab, they would not have detected the virus.
The Pennsylvania cat was taken to the vet with symptoms of anorexia, lethargy, vomiting and loose stools for several days. His owner contracted COVID 11 days earlier and had since isolated himself from his pet for fear of making him sick. When the cat was found to have coronavirus, it was too late to get a nasal swab from the owner, compare the two infections, and have any idea how the feline had become infected or what aspect of its infection allowed the virus to jump the species barrier.
The fact that this is the first official report of a cat carrying the AY.3 lineage suggests that we should not be complacent about transmission between our pets.
“One of the main takeaways is that as different variants of SARS-CoV-2 emerge, they seem to retain the ability to infect a wide range of species,” says Lennon.
Due to the changing nature of COVID, any viral reservoir poses a danger to humans and other animals. Just because cats don’t seem to be causing mutations or transmission now doesn’t mean it will always be that way.
Referencia: Lenz, O.C.; Marques, A.D.; Kelly, B.J.; Rodino, K.G.; Cole, S.D.; Perera, R.A.P.M.; Weiss, S.R.; Bushman, F.D.; Lennon, E.M. SARS-CoV-2 Delta Variant (AY.3) in the Feces of a Domestic Cat. Viruses 2022, 14, 421. https://doi.org/10.3390/v14020421
