RATS in NYC harbor Covid, study shows – and experts fear it poses a zoonotic threat to humans
Rats in New York City harbor Covid, a study has warned — and scientists are concerned they could infect humans.
Researchers at the University of Missouri captured 79 rats that emerged from the sewage system of city parks.
Tests showed that 13 of the rodents (16.5 percent) had antibodies to Covid, a sign of previous infection. Four had evidence that they were currently infected.
A separate test revealed that rats could be infected with the Alpha, Delta and Omicron Covid strains, showing that the rodents can harbor many variants.
With eight million rats living in America’s largest city — or about one per resident — experts warned they posed a serious risk of “zoonotic disease spillover.” When viruses jump between species, it increases the risk of them acquiring significant mutations, which could make them more transmissible or deadly.
Rats in New York City sewers harbor Covid, scientists warn, and may even infect humans (stock image)
Dr. Henry Wan, a microbiologist at the University of Missouri who led the study, said: “Our findings highlight the need for further monitoring of SARS-CoV-2 in rat populations for possible secondary zoonotic transmission to humans.
Overall, our work in this area shows that animals can play a role in pandemics that affect humans.
‘It is important that we continue to increase our insight [of the risks posed] so that we can protect both human and animal health.’
Rats can be exposed to Covid when they come into contact with water that is also used by people infected with the virus, which can happen in sewers.
The virus could then potentially infect the rats, because the rodents have receptors on their cells that are similar to those in humans.
Scientists fear Covid could potentially move to another animal reservoir and then mutate into a more severe version before jumping back into humans.
Some experts argue that this is how the Omicron variety, the currently dominant strain, emerged when rats in South Africa’s water systems became infected.
In the study, published today in the journal mBioscientists said they set rat traps in September and November 2021.
The traps were usually placed in Brooklyn city parks, near wastewater systems. Some were also caught near buildings outside the park boundaries.
All rats caught were of the species called Norwegian rats, with the Latin name Rattus norvegicus.
All have had blood tests for antibodies to Covid, indicating infection.
All rodents were tested for antibodies to Covid, which would indicate an infection. Thirteen tested positive.
Four rats tested positive for proteins from the virus, indicating they currently had an infection. A partial Covid genome was subsequently recovered from each.
The scientists also performed a challenge study, where they exposed a different group of rats to the three main Covid variants: Alpha, Delta and Omicron.
Examination two to four days after infection showed that each had led to infection in the rats.
For Omicron, the scientists used the variant BA.5.5 – which was responsible for about one in ten infections at the turn of the year.
Scientists fear the next major pandemic will be the result of a disease that spreads from animals to humans.
There are currently growing fears that a strain of bird flu H5N1 could cross the divide from chickens to humans.
This year, 11-year-old Bean Narong became the first person to die after contracting this strain of bird flu in her impoverished village in Cambodia.
The World Health Organization has urged countries to keep an eye on the species, amid reports that it has also evolved to infect minks and sea lions – bringing it one step closer to humans.