The Evandro Chagas National Infectiology Institute – INI and the Oswaldo Cruz Institute (IOC) are developing a pioneer study to understand whether there is a correlation between exposure of pets to Covid-19 and human infection by the virus. The study relies on the support of the Laboratory of Respiratory Viruses and Measles of the IOC, a reference in the Americas for coronavirus studies.

The research is following the cases of 21 patients and 39 pets (29 dogs and 10 cats) in the metropolitan region of Rio de Janeiro, who were infected between May and October 2020. After confirming the human cases, researchers analyzed nasopharyngeal and rectal samples obtained from the pets and carried out Plaque Reduction and Neutralization Test (PRNT90), to check whether the animals had developed antibodies against the disease.

According to Guilherme Calvet, who coordinated the study, the main results show that, in 21 different households, almost half had one or more animals that tested positive for Covid-19 infection between 11 and 51 days after their owners presented the first symptoms of teh disease. Forty-six of the infected animals had mild and reversible clinical signs that might be associated to the virus. The study observed that neutered animals are more susceptible.

The results were published in the international scientific magazine Plos One, and the cases were reported to the Brazilian Ministry of Agriculture, Livestock and Supply, which pretented them at the plaatform The World Organization for Animal Health (OIE).

The study concludes that, if tested positive for coronavirus, individuals should practice social distancing not only from other people, but also from their pets, as they can be infected as well. The viral loads in these animals are low enough to keep them from transmitting to humans, therefore there is no reason to abandon an animal that tests positive for the disease. In other words, humans can transmit the virus to humans and animals, but animals cannot transmit it to humans.