Rats in New York City have been the subjects of research to find out just how many types of bacteria and viruses they can harbor. The verdict? A lot, say scientists from Columbia University.
After a year during which they collected more than 130 rats, the researchers found that in addition to some well-known pathogens like the food-borne disease salmonella and fever-causing viruses, the rats were harboring "novel" pathogens, unknown to New York and to science at large.
"We ... identified a wide range of known and novel viruses from groups that contain important human pathogens, including sapoviruses, cardioviruses, kobuviruses, parechoviruses, rotaviruses, and hepaciviruses," the researchers report in the journal mBio.
Two new hepacivureses detected in the rats may suggest an animal model that's the closest relative of human hepatitis C virus, they said.
Seoul hantavirus, which can cause a hemorrhagic fever similar to Ebola and kidney failure in humans, was also found, they said.
The researchers used DNA to catalog the pathogens discovered in what they said was the first known attempt to identify the full range of pathogens present in any species of animal inhabiting New York City.
"Everybody's looking all over the world, in all sorts of exotic places, including us," Columbia professor of neurology and pathology Ian Lipkin says. "But nobody's looking right under our noses."
The researchers said the study of New York City rats would give them a point of comparison in the event of a pathogen crossing over and presenting a new threat to public health.
"Rats are sentinels for human disease. They're all over the city; uptown, downtown, underground," Lipkin says. "Everywhere they go, they collect microbes and amplify them. And because these animals live close to people, there is ample opportunity for exchange."
The pest control firm Orkin has rated New York City fourth on its list of "rattiest" U.S. cities, behind Chicago, Los Angeles and Washington, D.C.
The list was compiled from the company's records of where it performed the most rat-eradication treatments, it said.
None of the researchers would argue the city doesn't belong on the list.
"New Yorkers are constantly exposed to rats and the pathogens they carry, perhaps more than any other animal," says study first author Cadhla Firth, who led the study as a research scientist at the university's Center for Infection and Immunity.
"Despite this, we know very little about the impact they have on human health."