Leptospirosis Cases Rise in NYC: What You Should Know About Rat-Spread Infectious Disease

New York City has reported an increase in human cases of leptospirosis, a bacterial disease that the city reports was transmitted from rats.

In a recommendation made in late September, the city’s Department of Health and Mental Hygiene reported that 14 cases of human leptospirosis had been identified this year, a number reportedly higher than the total reported by the city’s health department in any previous year was reported.

In all counties with the exception of Staten Island, cases were identified without an “obvious cluster”.

Bat Bites and Rabies: WHAT YOU KNOW

Thirteen of the 14 people were hospitalized with acute kidney and liver failure, and two of the patients also reportedly had severe lung involvement.

One person died of an infection, everyone else was treated and discharged.

Three of the infected are said to have been homeless and one person was on the move when infected.

Most cases had a “clear history or risk factor” that exposed them to a severe rat infestation environment, the report said.

A rat walks along the High Line Park in New York City on September 22, 2018.
(Photo by Gary Hershorn / Getty Images)

A health official reportedly told Insider that there was a 15th case of the zoonosis last week and that the infected person appears to have recovered.

Deputy Commissioner of the Department’s Disease Control Division, Celia Quinn, noted that the health department conducted inspections and worked with landowners to carry out rat cleanups.

Last May, the U.S. Centers for Disease Control and Prevention (CDC) warned that rats were likely to become more aggressive due to the effects of the COVID-19 pandemic.

The department said New York City documented a total of 57 cases between 2006 and 2020.

In 2017, a quarter of the Bronx was targeted by the health department after one person died and two more became seriously ill with leptospirosis, including a man with the first documented case of testicular swelling related to the disease.


Animals and pets can get sick too, and New York issued a veterinary warning that same year.

The Big Apple is home to millions of rats and was ranked third on Orkin’s list of America’s “rattest cities” behind Chicago and Los Angeles.

According to the CDC, leptospirosis infection in humans occurs through contact with the urine of infected animals or other body fluids – with the exception of saliva – or contact with water, soil or food contaminated with the urine of infected animals.

Symptoms of the disease include high fever, headache, chills, muscle aches, vomiting, jaundice, red eyes, abdominal pain, diarrhea, and rash. However, some people may experience no symptoms at all.

Three rats search for food on the subway platform in Herald Square Sept. 3, 2017 in New York City.

Three rats search for food on the subway platform in Herald Square Sept. 3, 2017 in New York City.
(Photo by Gary Hershorn / Getty Images)

The time between a person’s exposure to the contaminated source and the disease is two days to four weeks.

After the first phase of the disease, the patient can recover but get sick again, and the second phase is more severe and leads to kidney damage, meningitis, liver failure, shortness of breath, and death.

The illness lasts from a few days to more than three weeks, and recovery can take several months without treatment.

Leptospirosis is treated with antibiotics such as doxycycline or penicillin, which should be given early in the course of the disease.


Humans can reduce the risk of disease by not swimming in contaminated water or by avoiding contact with potentially infected animals.

The agency found that leptospirosis is most common in temperate or tropical climates and that the incidence of leptospirosis infections appears to be increasing in urban children.

The Associated Press contributed to this report.

Comments are closed.