E-Paper
Cats susceptible to virus, but may not infect humans
New Delhi: Ferrets and cats are susceptible to contracting coronavirus (Covid-19) but not dogs, ducks, chickens and pigs, a non-peer reviewed study published in
New Delhi: Ferrets and cats are susceptible to contracting coronavirus (Covid-19) but not dogs, ducks, chickens and pigs, a non-peer reviewed study published in bioRxiv has found and said these findings can be important for vaccine and antiviral drug development for the disease. BioRxiv is a free online archive and distribution service for unpublished preprints in life sciences.
There is, however, no reason for panic among pet keepers or cat lovers because the findings are based on only lab experiments, and there has been no study on whether cats can pass on the infection to humans, according to experts. It is also unclear which species of cats was used for the experiments for the study.
According to the authors Hualan Chen et al, the experiments were conducted to understand how the virus behaves in animals and which among them can be used to model the efficacy of control measures in humans like drugs or vaccines.
The authors are scientists affiliated to Harbin Veterinary Research Institute (China), Chinese Academy of Agricultural Sciences and National High Containment Laboratory for Animal Diseases Control and Prevention (China).
The scientists isolated the virus from an environmental sample in a seafood market in China’s Wuhan, where the pandemic originated from, and some samples from humans. Animals studied were inoculated and the viral RNA load was quantified from organs of those euthanised and faeces of animals isolated.
“In summary, we found that ferrets and cats are highly susceptible to SARS-CoV-2 [which causes Covid-19], dogs have low susceptibility, and livestock including pigs, chickens, and ducks are not susceptible to the virus. Ferrets have frequently been used as an animal model for the study of human respiratory viruses. Unlike influenza viruses and other human SARS-coronavirus, which replicate in both the upper and lower respiratory tract of ferrets, we found SARS-CoV-2 only replicates in the nasal turbinate, soft palate, and tonsils of ferrets,” the study concluded.
But its too early to draw any conclusion on whether cats can contract the infection in natural conditions (non-experimental) and whether they can infect humans.
Dr Nivedita Gupta, a viral diseases expert at the Indian Council of Medical Research, said some animals will be susceptible to the virus and that is how animal models are created for research on vaccines. “But to jump to the conclusion that they can infect pet owners and humans is not right. We have domestic cats in India which can be very different from the cats in China. First, we need to understand what is the spill over point to cats there. Such spill overs happen due to zoonotic interface between humans and wild animals. In the SARS epidemic also we saw that civet cats were a reservoir of the virus. Nobody keeps civets as pets.”
Amit Singh, an associate professor at Benguluru’s Indian Institute of Science, said there is a question mark on whether an animal could have played an intermediate host in the transmission of SARS-CoV-2. “That is the most probable hypothesis in how the virus may have transmitted from bats to humans. The study is important because some animals are in close contact with us. The paper is also interesting because it has looked into infection replication and viral load. We cannot ignore these findings because cats and ferrets can then serve as elegant animal models to verify vaccine and anti-viral drug efficacy. It will add to fundamental science on Covid 19,” he said
Uma Ramakrishnan, an associate professor at the National Centre for Biological Sciences, called the study significant because it shows that cats and ferrets could be reservoirs for the virus. “The study is significant because it shows that cats and ferrets could be reservoirs for the virus. Macaques also have been found to contract the infection in other studies. It shows that the virus does replicate in them. But we can’t say yet whether they can transmit the infection to humans because the density of cats is not as high. Also, they have been infected during an experiment. We don’t know if they can get infected naturally,” she said.
Another study by Chinese Academy of Medical Sciences published on March 14 in BioRxiv said rhesus macaques can be infected and show symptoms of the disease. There was weight loss in some infected monkeys and viral replication was noticed in nose, pharynx, lung and gut and some also developed interstitial pneumonia.
Some media reports have suggested that even dogs can be infected. Bloomberg carried a report on March 19 saying two dogs tested positive for the virus in Hong Kong.
