Rats, whose populations in cities have sparked the pandemic, have now joined the list of wild animals believed to be able to contract and transmit the virus that causes COVID-19, according to a new study.
In a paper published Thursday in the journal mBio, researchers showed that rats, such as dogs, cats, hamsters, ferrets and other close cohabitants of humans, can contract the pandemic virus in their environment.
They don’t seem to get very sick; None of the wild rats intentionally inflamed in a lab lost weight or died from it. But when rats were exposed to the Alpha, Delta and Omicron variants of the SARS-CoV-2 coronavirus, the researchers discovered evidence of physically powerful viral replication in the animals’ noses, mouths, throats and lungs.
In addition, a detailed examination of 79 of the so-called brown rats (Rattus norvegicus) collected from sewers in and around New York City revealed telltale symptoms that thirteen had been exposed to the coronavirus and had developed an immune response. In fact, PCR tests of the rats’ respiratory tissues reported that 4 of the 79 rats had active infections when they were euthanized.
Studies conducted through U. S. Department of Agriculture scientists. The U. S. Department of Homeland Research, Walter Reed Army Research Institute, and the University of Missouri. This brings to 11 the number of wild “reservoirs” known for the pandemic virus, which also infects deer, mink and otters. , gorillas, lions and tigers.
The presence of the virus in all those species not only ensures that the coronavirus will never disappear from our home, but also raises the option that, as the ever-evolving virus adapts to many other new hosts, it evolves into tactics that make it unrecognizable. to humans who thought they were immune to it.
Brown rats, also known as brown rats, have coexisted with humans for thousands of years and are prolific transmitters of human disease. Exposure to your feces, urine, or saliva is known to cause hantavirus, leptospirosis, lymphocytic choriomeningitis, tularemia, and salmonella.
As the pandemic winds down, the new findings suggest a chilling situation in which wild rats, whose populations in American cities have grown explosively over the past three years, may not only be a vector for reinfecting humans, but also a source of new variants that escapes our anti-vaccine coverage or beyond contagion.
If the coronavirus recombines with the rat-borne virus, or if it simply evolves to spread more smoothly within that population, the result could be a new pathogen capable of restarting the pandemic, the study authors said.
The findings highlight “the need for additional surveillance of SARS-CoV-2 in rat populations for possible transmission to humans,” they wrote.
Other researchers have warned that biological differences between humans and wild rats have turned this wild population into fertile soil for introducing mutations in the SARS-CoV-2 virus.
The authors cite a study suggesting that rodents could have played a role in the evolution of the Omicron variant. This speculation is based on the fact that some of the Omicron mutations improved the virus’s ability to attach to rodent cells even more than they did. It took a step forward in its binding to human cells. But co-author Henry Wan of the University of Missouri School of Medicine said “it’s still just speculation. “
The challenge remains whether and how inflamed rats can transmit the coronavirus to humans.
The study authors showed that, under laboratory conditions, rats inflamed with a similar coronavirus developed infections and excreted the virus. And, just like humans, those rats can become repeatedly inflamed.
The discovery that those inflamed rats are capable of spreading their germs raises the puzzling prospect that when rats in the wild rush onto surfaces touched by humans, their noses may simply deposit respiratory secretions that transmit the virus to humans. While aerosol transmission has been the number one means through which the coronavirus has spread among humans, getting the virus through touch is also a concern.
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Melissa Healy is a science and fitness reporter for the Los Angeles Times and writes from the Washington, D. C. area. It covers prescription drugs, obesity, nutrition and exercise, as well as neuroscience, intellectual fitness, and human behavior. He has been at The Times for more than 30 years and has covered national security, the environment, domestic social policy, Congress and the White House. As a baby boomer, he largely follows trends in midlife weight gain, memory loss, and red wine fitness.
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