快猫短视频

Recent studies suggest SARS-CoV-2, the virus that causes covid-19, is rife among the 30 million white-tailed deer in North America. This means there is a risk of deer infecting other animals, and also of new variants emerging in animals and jumping back to people. So what does this mean for the pandemic and how concerned should we be?

It has long been clear that people with SARS-CoV-2 are occasionally infecting pets, farm and zoo animals. Until now, however, it was thought that outbreaks in animals had either died out or been eliminated.

For instance, in November 2020, Denmark culled millions of mink after the virus began spreading in farmed mink, and these mink then infected a few farm workers.

Now, and at Pennsylvania State University and their colleagues have found an astonishingly high rate of infection among white-tailed deer in Iowa. The team has been testing 5000 samples taken up to January 2021.

After a third of PCR tests on the first 300 samples came up positive, the researchers decided to . 鈥淭his is the first evidence of any free-living wild animal species having widespread SARS-CoV-2 infection,鈥� says Kuchipudi.

The researchers think what they have found is the tip of the iceberg. It is likely that the coronavirus is common in white-tailed deer across North America, they say, and it will probably keep circulating indefinitely because deer populations have a high turnover rate.

The extent of the problem may have gone unnoticed for so long because white-tailed deer show few symptoms when infected. It is quite possible that SARS-CoV-2 is also spreading unnoticed in other wild species elsewhere in the world, says Kapur.

鈥淭he search for wildlife reservoirs has not been as much or as comprehensive as one might have hoped,鈥� he says. 鈥淲e could have these effectively silent epidemics and, who knows, pandemics going on among wild species that we are completely unaware of.鈥�

SARS-CoV-2 infects a surprisingly wide range of animals. The list includes mustelids such as mink and ferrets, seals, some rodents, cats, dogs and other canids, cows and other ungulates, bats and perhaps even .

There are two main dangers. Firstly, the more animals that harbour the virus, the more risk there is of other species being infected. In some species, SARS-CoV-2 might be more lethal, which could be bad news for endangered species.

Secondly, if there are animal reservoirs of SARS-CoV-2, there is a risk of new and potentially dangerous variants emerging and jumping back to people. This risk is sometimes exaggerated, however.

While there is some evidence that SARS-CoV-2 mutates more rapidly when it first jumps to animals, there is no reason to think that the mutations that emerge in animals will be more dangerous than those constantly occurring in the viruses spreading among humans. As long as SARS-CoV-2 continues to circulate widely in people, we will remain the most likely source of dangerous new variants such as alpha and delta.

That said, the virus will evolve differently in animal reservoirs. 鈥淚f it manages to circulate in more than one host, the way it changes becomes twice as complicated,鈥� says Kuchipudi.

In the long run, we could end up with a situation like that of flu, which circulates in a number of animals, says Kapur. Every now and then, an animal strain jumps to people, sparking a pandemic.

For instance, the 1918 flu pandemic was caused by H1N1 bird flu jumping to people. This strain kept circulating in humans, but also spread to pigs in around the 1930s. In 2009, an H1N1 pig strain jumped back to people and caused the 2009 swine flu pandemic.

This kind of scenario now seems likely to play out with the coronavirus, too.

Sign up for a weekly newsletter of 快猫短视频鈥檚 best content for Americans