NYC faces major rat urine problem 

Health authorities have issued an advisory as cases of human leptospirosis have hit a record high 

New York City health authorities have recorded a significant rise in cases of human leptospirosis, a disease caused by contact with the urine of animals, particularly rats. 

According to an advisory issued by the city’s Department of Health and Mental Hygiene on Friday, six people have been diagnosed with the disease so far this year, while 24 cases were reported in 2023, marking the highest number in a single year. The authorities attribute the rise to a soaring number of rats in the city.

If left untreated, leptospirosis can lead to kidney failure and liver damage. The ailment is caused by several species of bacteria transmitted through animal urine or feces, or contaminated water or soil if comes into contact with the eyes, mouth, nose or breaks in the skin. Among the most common symptoms of the disease are a fever, headaches and chills.   

New York City has one of the highest populations of brown rats in the US. Researchers from the city’s pest control company estimated that there were approximately three million rats in the city as of August 2023, finding that the number had increased by nearly 50% in the past decade. Rats are prodigious breeders, with one pair having the potential to produce as many as 15,000 offspring in a year. 

The rise in leptospirosis infections comes a year after Mayor Eric Adams appointed Kathleen Corradi as the Big Apple’s first ever director of rodent mitigation, or “rat czar.” The position was created as part of an effort to bring down the booming rat population in the city. 

READ MORE: New York mayor appoints ‘rat czar’

As part of the effort to finally eradicate the longstanding problem, the City Council introduced a new bill earlier this week that would require the Health Department to use salty pellets that sterilize both male and female rats in two neighborhoods as part of a pilot program. 

The pellets would be deployed within so-called rat mitigation zones covering at least ten city blocks.

In their advisory the Health Department stressed that leptospira bacteria are fragile and can die within minutes in dry heat or freezing temperatures but that “excessive rain and unseasonably warm temperatures, factors associated with climate change, may support the persistence of leptospires in more temperate areas like NYC.”