a potential reservoir of new SARS-CoV-2 variants?

U.S – There are increasing reports of American deer infected with SARS-CoV-2 and sick with Covid-19. The phenomenon has also been observed in zoos or pets. Some experts fear that animals not only become a source of transmission of the virus to humans, but also that they represent a reservoir for the development of new variants.

Deer and cats concerned

Last July, the United States Department of Agriculture revealed that antibodies against SARS-CoV-2 were detected in white-tailed deer in Illinois, Pennsylvania, Michigan and New York. A month later, the department reported the presence of the virus in deer in Ohio. A few weeks ago, researchers at Penn State University published a study showing that an increasing number of deer tested positive in Iowa, which likely reflects transmission from human to deer (the phenomenon being mostly observed in animal parks) and then between deer.

Meanwhile, three snow leopards housed at Lincoln Children’s Zoo in Nebraska recently died from complications from Covid-19. Two tigers at the zoo also contracted the virus in October but recovered. A similar phenomenon occurred in Smithsonian National Zoo from Washington DC in September, with six African lions, one Sumatran tiger and two Siberian tigers testing positive for SARS-CoV-2. Zoo staff were unable to determine the source of these infections.

Humans infected animals

So far, and although the cause is sometimes unknown, it seems that more humans are infecting animals. So, according to Angela Bosco Lauth (Assistant Professor of Biomedical Sciences at Colorado State University, Fort Collins) Humans are the suspected vector of infection in deer. On the other hand, “the probability of a human contracting the disease from a deer they have just killed is quite minimal, although it cannot be completely ruled out. “And to add, underlining the sheer number of infections in the world, that ‘what we’re seeing is unprecedented in history. What is even more worrisome is the possibility of a new variant appearing, particularly in domestic or farm animals. We saw in particular with the delta variant that mutations appear quite easily and adapt to the host. »

Angela Bosco-Lauth and her colleagues recently performed experiments on cats, dogs, hamsters and ferrets. They found rapid evolution of SARS-CoV-2, mostly in dogs and cats. In their study, published in early November in the journal Proceedings of the National Academy of Sciencesthe authors suggest closely monitoring the evolution of SARS-CoV-2 in pets and other potential animal hosts.

Given that cats seem particularly susceptible to infection by this virus and that they live very close to humans, we would be in the presence of “a more likely context of bidirectional transmission, between humans and animals, which could give rise to variants” worries Angela Bosco-Lauth.

The US Centers for Disease Control says humans can transmit Covid-19 to animals, including domestic animals, zoos or farm animals such as mink. The Agency points out, however, that there is still no evidence that Covid-19 can be transmitted from animals to humans, with the exception of farmed mink.

Denmark culled millions of mink in 2020 to prevent a mutation that occurred after human-to-animal and animal-to-human transmission. The country then cremated 4 million of these minks who had been hastily buried a few months earlier.

Caution is advised for hunters

SARS-CoV-2 is not transmitted through blood and there is no evidence that a person can get sick from eating venison, but some states recommend that hunters take extra precautions when preparing dishes. Most of these states advise them to follow the CDC’s recommendations for wild game management, which advises not taking animals that appear sick or found dead, avoiding cutting the spine and spinal tissue, not eating the brains of wild animals, and wearing gloves. rubber or disposable.

Thus, Wisconsin suggests wearing a mask and advises hunters to also limit manipulation or cutting of the lungs, throat, snout and nostrils. Massachusetts advises wearing a face mask in addition to CDC guidelines. A wildlife biologist from the state of Rhode Island told the Providence Diary that he recommended wearing a mask when dealing with deer in the field.

Most US states recommend the Covid vaccine, which they consider the best way to protect against possible infections, even from animals.

Extra precautions are never unnecessary, said Angela Bosco-Lauth, adding that “wearing a mask to prevent pathogens other than SARS-CoV-2 is a good idea.”

This article was originally published on Medscape.com under the title Spread of COVID among deer causes concern about new variants . Translated by Dr. Claude Leroy.

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