Cats might be able to contract SARS-CoV-2, but evidence is limited
A preliminary study shows that cats can contract the brand new coronavirus, yet this happened within an artificial context where scientists gave the felines high doses of SARS-CoV-2. The study didn't prove convincingly that cats could actually transmit the virus further, between themselves or to humans.
One key question that scientists have not had the opportunity to answer satisfactorily through the COVID-19 pandemic is: Can domestic animals contract SARS-CoV-2, the virus that can bring about this disease?
Moreover, if the answer is “yes,” which domestic animals are in risk, and are they able to shed the virus further, transmitting it to other animals and humans?
One report from Hong Kong indicated that a pet Pomeranian tested “weak positive” for infection with SARS-CoV-2. The results suggested that was a case of human-to-animal transmission, and the authorities who tested it kept the animal in quarantine for a couple days, even though it did not show any observeable symptoms.
In the meantime, the dog - that was 17 years old - has died, though, if the virus was in any way responsible for its passing remains uncertain.
Since that time, another dog in Hong Kong - this time around, a German Shepherd - tested positive for infection with the virus, though once more, the canine will not show any symptoms.
And most recently, a cat in Belgium that showed respiratory and digestive symptoms also tested positive for a coronavirus infection. In this case, however, some scientists have raised doubts about whether this is a SARS-CoV-2 infection, and whether the cat’s symptoms were linked to the infection.
Cats and ferrets, yes, dogs and pigs, no?
Due to high level of contradictory information around the opportunity of SARS-CoV-2 transmission in domestic animals, researchers from China made a decision to take further steps to look into the matter.
The researchers hail from the Harbin Veterinary Research Institute at the Chinese Academy of Agricultural Sciences, and the National High Containment Laboratory for Animal Diseases Control and Prevention, both in Harbin, China.
While their study hasn't yet undergone peer review, plus they have not published it in virtually any scientific journal, the authors are making their findings available online in preprint form.
Within their research, they viewed if the new coronavirus could infect a variety of domestic or companion animals, including cats, dogs, ferrets, chickens, ducks, and pigs.
Their most salient finding was that cats and ferrets seem to be the most vunerable to infection with SARS-CoV-2, while in dogs, pigs, chickens, and ducks, the virus “replicates poorly,” based on the study authors.
Yet, it really is unclear how likely cats and ferrets are to contract the virus, given the completely artificial method of infection that the scientists used.
Cats inoculated with high load of virus
The researchers inoculated five 8-month-old domestic cats with a higher dose of the virus, that they delivered directly to the cats’ noses.
After 6 days, they euthanized two of the cats to acquire samples from different parts of their bodies and look for viral RNA. From the rest of the cats, the researchers collected and analyzed fecal samples.
The researchers found that post mortem, both euthanized cats presented viral RNA within their noses, mouths, and tonsils, while one of these also had traces of the virus in its trachea, and another in its small intestine. They found no viral RNA in the cats’ lungs.
In conditions of infectious viral RNA - traces of virus that could actually replicate further - the researchers only found those in the two cats’ noses, mouths, tonsils, and trachea.
As for the other three cats, “[i]n the transmission study, viral RNA was detected in the feces of two virus-inoculated subadult cats on day 3 [following infection], and in all three virus-inoculated subadult cats on day 5,” study author Jianzhong Shi and colleagues write. The researchers had isolated most of these cats in separate cages.
The analysis team exposed a sixth young cat to the three that it had already inoculated with the virus, which cat became infected too. The investigators found traces of viral RNA in its feces on the 3rd day after exposure.
Source: www.medicalnewstoday.com
