Cats can become infected with the new coronavirus but dogs appear not to be vulnerable, according to a new study in the journal Science, prompting the World Health Organization (WHO) to say it will take a closer look at the transmission of the virus between humans and pets.

The study, published on Wednesday, found that ferrets can also become infected with SARS-CoV-2, the scientific term for the virus that causes the disease COVID-19.

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The Science journal findings support an earlier study by Hong Kong's Agriculture, Fisheries and Conservation Department that pet cats, and even some dogs, can host the disease.

The Hong Kong study, however, said cats and dogs cannot pass the new coronavirus to humans, even if they can test positive for low levels if they catch it from their owners.

The study, published in Science was aimed at identifying which animals are vulnerable to the virus so they can be used to test experimental vaccines to fight the coronavirus pandemic, which has so far killed more than 88,000 people around the world since it emerged in China late last year.

The disease is believed to have spread from bats to humans. There have been a handful of reported infections in cats and dogs, but no strong evidence that pets can be carriers.

A tiger at the Bronx Zoo in New York City that developed a dry cough and loss of appetite after contact with an infected zookeeper who tested positive for the coronavirus on Sunday.

The study, based on research conducted in China in January and February, found cats and ferrets highly susceptible to the virus when researchers attempted to infect the animals by introducing viral particles via the nose.

Kittens infected

They also found cats can infect each other via respiratory droplets. Infected cats had virus in the mouth, nose and small intestine. Kittens exposed to the virus showed significant lesions in their lungs, nose and throat.

"Surveillance for SARS-CoV-2 in cats should be considered as an adjunct to elimination of COVID-19 in humans," the authors wrote.

In ferrets, the virus was found in the upper respiratory tract but did not cause severe disease.

Antibody tests showed dogs were less likely to catch the virus, while inoculated pigs, chickens, and ducks were not found to have any strain of the virus.

"It's both interesting and not terribly surprising in the sense that with the original SARS epidemic, civet cats were implicated as one of the vectors that may have transmitted virus to humans," said Daniel Kuritzkes, head of infectious diseases at Boston's Brigham and Women's Hospital.

"What these data do provide is support for the recommendation that people who are with COVID-19 should be distancing themselves, not only from other household members but also from their household pets, so as not to transmit the virus to their pets, particularly to cats or other felines," he said.

The WHO said on Wednesday it is working with its partners to look more closely at the role of pets in the health crisis.

The WHO said on April 8 it is working with its partners to look more closely at the role of pets in the health crisis [ Andreea Alexandru/AP]

Based on the evidence so far, WHO epidemiologist Maria Van Kerkhove told a news conference: "We don't believe that they are playing a role in transmission but we think that they may be able to be infected from an infected person."

The WHO's top emergencies expert Mike Ryan asked people not to retaliate against animals over the outbreak.

"They're beings in their own right and they deserve to be treated with kindness and respect. They are victims like the rest of us," he said.