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Rats in New York
Photo: Lokman Vural Elibol / AA / picture alliance
New York City is considered a rat stronghold.
About two million of the animals live here and now it shows - the rodents can become infected with the Sars-CoV-2 coronavirus.
This is indicated by a study by US experts from the University of Missouri, among others, which has been published on a preprint server and has not yet been checked by independent experts.
In the fall of 2021, the researchers captured 79 brown rats in the Brooklyn borough of New York.
13 of them carried antibodies against the corona virus, so they were apparently once infected with the pathogen.
The PCR test was also positive in four rats.
So they were acutely infected.
Whether the animals can also transmit Covid remains to be seen.
Tests with laboratory rats showed that these rodents are susceptible to infections with alpha, delta and omicron viruses and that Sars-CoV-2 is spreading rapidly in their upper and lower respiratory tract.
Origin of mysterious mutations still unknown
The study was an attempt to better explain findings of previously unknown corona mutations in New York sewage.
The discovered virus fragments had not been detected in any human before, experts reported at the end of March 2022 in the journal "Nature Communications".
Some of the sections of the genome have adaptations to the receptors of mice and rats.
It was already being discussed at that time whether the unknown parts of the virus could possibly come from a reservoir in animals.
The new study supports this thesis, but does not provide any clear evidence that the mutations actually developed in rats and got into the sewage from there.
Sars-CoV-2 has now been detected in numerous animal species, including white-tailed deer and mink, but pets such as dogs and cats can also become infected.
How the New York rats got infected with the virus remains open.
Although the coronavirus can be detected in wastewater, these virus residues are not infectious.
Instead, the researchers consider leftover food from humans to be the probable source.
"In summary, our results indicate that rats in the urban sewage systems of New York City came into contact with Sars-CoV-2," writes the specialist team.
The study provides evidence of a potential risk of transmission from urban rats to humans and highlights the need to monitor such populations.
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