A new study from Columbia University has found previously unknown infections living in Manhattan’s street rats, some of which are similar to the human hepatitis C virus (HCV), Medical Daily reports.

Published in the journal mBio, the study examined 133 rats. Within the blood, tissue, feces and urine samples, researchers found a plethora of pathogens, including bacteria that can cause diarrhea and food poisoning, as well as several viral infections that cause fevers in humans.

Also identified in the rats were 18 new viruses related to human viruses. Two of these new species appeared to be very similar to hep C. However, the researchers noted that it wasn’t entirely clear whether the rats could pass these diseases on to people.

While the study warns of the potential public health ramifications of increased rodent infestations in urban areas, researchers believe the HCV finding could be a silver lining.

Hep C has been a notoriously mysterious disease, because lab animals infected with human strains of the virus don’t show the same symptoms as people. But infecting lab rats with the newly discovered rodent-specific viruses could lead to a new animal model for the disease.

Other health officials claim the New York City data on rat populations could also help scientists better understand how diseases are spread around other urban areas.

The Columbia researchers are now working with the New York City Department of Health and Mental Hygiene and the Centers for Disease Control and Prevention to look at signs of these rat-borne infections in human New Yorkers.