A team from the French National Research Institute for Sustainable Development collected blood samples from 47 cats and dogs that lived with families in which at least one member had tested positive for Covid-19.
They then ran three tests on the samples for Sars-CoV-2 antibodies. More than 20 per cent of the animals returned a positive result in all three tests and 53 per cent did so in at least one.
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Earlier studies put the risk of a family pet becoming infected at between zero and 15 per cent.
The French study was published on the preprint website bioRxiv.org on Tuesday, meaning its findings have not been peer-reviewed.
“Our results highlight the potential role of pets in the spread of the epidemic,” said Dr Eric Leroy, the team’s leader.
“[The] infection risk in the pets of Covid-19 positive owners is much higher than previously described,” he said.
Leroy said his team did not retrieve any living strains of the coronavirus from any of the pets, which suggested it was very unlikely the pathogen could be passed by the animals to humans they encountered while outside their homes.
However, people who were in frequent close contact with an infected animal should take precautionary measures, he said.
Cats were about twice as likely to catch the virus than dogs, the results showed, supporting an earlier experiment by Chinese scientists.
Meanwhile, a separate study carried out by scientists in Spain found that the death rate among dogs suffering from respiratory disease soared during the pandemic.
Based on data collected from vets between April and June, the team found that the death rate rose from a norm of 1 to 2 per cent to as high as 40 per cent.
The team said in a paper published on bioRxiv.org on Tuesday that it was unclear if the spike could be attributed to the health crisis affecting humans, but coronavirus antibodies were found in some of the 40 dogs that got sick or died in the period.
“The number of deaths was more than 30 times higher than expected,” said the team’s leader, Dr Alicia Barbero-Fernandez from the University Alfonso X the Wise in Madrid.
“Information regarding the possibility of companion animals becoming infected is confusing and controversial.”
The global pandemic has shown the coronavirus is well adapted to humans, which in theory means it should be less likely to pass to other species.
However, some studies by Chinese scientists have found that the host range of the virus is determined by only a small number of genes, and that a single mutation in any one of them could make the virus more adept at making the switch.
More from South China Morning Post:
- Cats more susceptible to Covid-19 than dogs but pet lovers have ‘no cause for alarm’: researchers
- Coronavirus: ‘very unlikely’ Hong Kong dog that tested positive died from Covid-19, source says, citing old age, underlying illnesses
- Coronavirus: in China, the pandemic payoff has been good for pets, with interest in them increasing
This article Coronavirus: pets may be more susceptible to Covid-19 than first thought, study says first appeared on South China Morning Post