New York City's health department said there have been 14 human cases of leptospirosis, including one death, this year as of Sept. 22, more than the total number of cases reported to the city than any other year.
Thirteen of the patients were hospitalized with acute renal and hepatic failure. Of those, two also had severe pulmonary involvement, according to an advisory from the health department.
One person contracted their infection while traveling, while the rest acquired their cases locally.
"Most cases had a clear history or risk factor which exposed them to an environment with a severe rat infestation," the advisory said, adding that three of the patients were experiencing homelessness.
The disease is caused by bacteria of the genus Leptospira and affects both humans and animals. The bacteria can spread through the urine of infected animals and can survive in water or soil for weeks to months, according to the CDC. Leptospirosis can be spread by many different animals, including cattle, pigs, horses, dogs and rodents. In New York City, it's often spread by rats, the health department said.
Leptospirosis is associated with a range of flu-like symptoms, including fever, headache and chills, as well as red eyes and jaundice. Some infected people may have no symptoms at all, but if left untreated, it may lead to kidney failure, meningitis, liver damage and respiratory distress. Antibiotics are used to treat leptospirosis, such as doxycycline or penicillin, which should be administered early in the course of illness, according to the CDC.
There were just 57 leptospirosis cases in New York City between 2006-2020.