Experts question study linking stray dogs to SARS-CoV-2 spread

After a study published in the journal Molecular Biology and Evolution proposed that stray dogs might have played a role in the initial transmission of the novel coronavirus that causes COVID-19, some experts called the findings "speculative".

Some fear that the "hypothesis" proposed in the study may contribute to changing the attitude of people towards street animals and those who care for them. Moreover, if some people take the theory presented in the study as facts, they might even abandon their dogs.

"I do not believe that any dog owners should be concerned as a result of this work," said Professor James Wood, Head of Department of Veterinary Medicine at University of Cambridge in the UK.

In the study linking stray dogs to spread of the disease caused by SARS-CoV-2, biology Professor Xuhua Xia at the University of Ottawa in Canada traced the coronavirus signatures across different species.

"Our observations have allowed the formation of a new hypothesis for the origin and initial transmission of SARS-CoV-2," said Xia.

"The ancestor of SARS-CoV-2 and its nearest relative, a bat coronavirus, infected the intestine of canids, most likely resulting in a rapid evolution of the virus in canids and its jump into humans. This suggests the importance of monitoring SARS-like coronaviruses in feral dogs in the fight against SARS-CoV-2."

But several experts found the link between dogs and the evolution of SARS-CoV-2 speculative.

"The theory that SARS-CoV2 originated in dogs seems to stem from speculation about CpG and high ZAP expression. This is speculative at best and certainly isn't strong evidence for the link," said Professor Mick Watson, Personal Chair of Bioinformatics and Computational Biology, Roslin Institute, University of Edinburgh, Scotland.

Scientists have been looking for an intermediate animal host between bats, which are known to harbour many coronaviruses, and the first introduction of SARS-CoV-2 into humans, but a definite answer has so far eluded researchers.

"I am confident that answers about the origin of SARS-CoV-2 are still out there, somewhere in the natural world, but we have not found them yet," said Professor Ben Neuman, Chair of Biological Sciences at Texas A&M University-Texarkana in the US.

"The conclusion that cats or dogs were involved as an intermediate host for SARS-CoV-2 is highly speculative, and should not be presented as fact," Neuman said.