While the WHO has initiated a study into the possibility of coronavirus infection spreading from humans to domestic animals after a four-year-old female Malayan tiger at the Bronx Zoo became the of its kind to test positive for the coronavirus, some veterinarians have argued that there is so far no clear evidence of human-to-animal reverse transmissions.
At the Bronx zoo, a total of four tigers and three African lions were also said to have developed a dry cough, a typical symptom of COVID-19 patients. Further, this week a study published on the website of the Science journal found that ferrets could also potentially become infected with SARS-CoV-2, the virus that causes the COVID-19 disease, however adding that dogs, chickens, pigs and ducks are not likely to get infected.
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However, Juliet Decaestecker, an India-based veterinarian from Belgium, and author of the book “Healthy Dog, Happy You,” said “Despite the number of global cases of COVID-19 surpassing the one million mark… we have only seen examples of two dogs and one cat in Hong Kong, and a tiger in New York, that had positive results of tests for infection.”
Speaking to The Hindu Dr. Decaestecker said that PCR testing conducted in these cases only concludes that virus material is present – a case of passive contamination – but that does not necessarily imply an ongoing infection in the animal that could be further transmitted. To be sure that there is an infection in the animal, antibodies testing must be performed.
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The presence of the coronavirus in case of the Bronx zoo tiger, Nadia, was due said to be due to the animal’s exposure via contact with a zoo employee who was actively shedding virus. At the broader, species level, “We can find virus fragments in the stomach or aerial pathways in dogs, but this could also be the virus… of the sick owner in close contact with the dog,” Dr. Decaestecker noted.
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In fact, domestic animals including dogs naturally carry other coronaviruses in their gastro-intestinal, respiratory tract, which are different from the novel coronavirus behind COVID-19, she said.
Given the lack of evidence for reverse transmission of the coronavirus, even if a companion animal presents respiratory or gastro-intestinal signs they should not be routinely tested for COVID-19 at this time, lest it exacerbates the scarcity of testing kits for humans, Dr. Decaestecker said. Instead, the animal’s owner should first consult with the veterinarian via phone to determine whether an in-clinic examination is needed. Where appropriate, testing for infectious diseases that commonly cause companion animal illness should be conducted. If a new, concerning illness is observed that cannot be otherwise explained, and the companion animal has had close and prolonged contact with a person with confirmed or suspected COVID-19 infection, the veterinarian should contact the state public health veterinarian or designated health official to discuss whether or not there is a need to test that animal for COVID-19.
Dr. Decaestecker said that in many cases there would be no reason to remove pets from homes even if COVID-19 has been identified in members of the household, unless there is risk that the pet itself is not able to be cared for appropriately. “During this pandemic emergency, pets and people each need the support of the other and veterinarians are there to support the good health of both,” she pointed out.
