Covid, first case of cat-to-human contagion

Covid, here's the first case of cat-to-human transmission. The first solid evidence of cat-to-human transmission of the SARS-CoV-2 virus has been reported. A group of researchers from Thailand has documented the case of a domestic cat infecting a human with the SARS-CoV-2 virus. They did so in a study published in the journal Emerging Infectious Diseases. The findings add felines to the list of animals that can transmit the virus to people.

Researchers say the results are compelling. They are surprised that it took so long to establish that transmission could occur, given the scale of the pandemic, the ability of the virus to jump between animal species, and the close contact between cats and people. “We’ve known for two years that this was a possibility,” Angela Bosco-Lauth, an infectious disease researcher at Colorado State University in Fort Collins, told Scientific American.

Studies early in the pandemic found that cats shed infectious virus particles and can infect other cats. And over the course of the pandemic, countries have reported SARS-CoV-2 infections in dozens of domestic cats. But determining the direction of viral spread—cat-to-person or person-to-cat—is tricky. The Thai study “is an interesting case and a great example of what good contact tracing can do,” says Marion Koopmans, a virologist at Erasmus University Medical Center in Rotterdam, the Netherlands.

The discovery was made by chance, says study co-author Sarunyou Chusri, an infectious disease researcher and physician at Prince of Songkla University in Hat Yai, southern Thailand. In August, a father and son who tested positive for SARS-CoV-2 were transferred to an isolation ward at the university hospital. Their XNUMX-year-old cat was also tested positive.

During the swab, the cat sneezed in front of a veterinarian, who was wearing a mask and gloves but not eye protection. Three days later, the veterinarian developed a fever, cold, and cough and later tested positive for Sars-CoV-2, but none of his close contacts developed Covid-19.

This suggested that he had been infected by the cat. Genetic analysis also confirmed that the vet had been infected with the same variant as the cat and its owners, and that the viral genomic sequences were identical. Researchers say these cases of cat-to-human transmission are likely rare. Experimental studies have shown that infected cats do not shed much virus and only do so for a few days, says Leo Poon, a virologist at the University of Hong Kong.

However, Chusri says it’s worth taking extra precautions when handling cats suspected of being infected. People “shouldn’t abandon their cats, but take better care of them,” he says. Other animals suspected of infecting people include farmed minks in Europe and North America, pet hamsters in Hong Kong, and wild white-tailed deer in Canada.

Adding cats to the list “broadens our understanding of the zoonotic potential of this virus,” Poon says. But researchers say these are all rare occurrences, and animals do not yet play a significant role in spreading the virus. “Humans are clearly still the primary source of the virus,” Bosco-Lauth says.