Leptospirosis is a disease caused by bacteria in the urine of infected animals. In NYC, rats are the most common cause of leptospirosis. Most infections occur from contact with the urine of an infected animal. Infections can also happen through contaminated water, soil or food. Bacteria can enter the body through the eyes, nose, mouth or an open wound. Leptospirosis is not usually spread from person to person.

Leptospirosis is rarely found in NYC, but the number of people diagnosed in the city has increased in recent years.


You can become sick between two days and four weeks after exposure. Some infected people may have no symptoms. Others may have a mild illness with:

  • Fever
  • Headache
  • Chills
  • Muscle aches
  • Vomiting
  • Diarrhea
  • Red eyes
  • Jaundice (yellow skin and eyes)

On rare occasions, severe illness can develop. This may cause kidney failure, liver failure or meningitis.


Rats are the most common source of leptospirosis. The best way to prevent leptospirosis is to avoid contact with rats. You can prevent leptospirosis by also following these tips:

  • Avoid places where rats may have urinated.
  • If you cannot avoid areas where there are rats, or if you are cleaning areas where rats have been, use a solution of one part bleach and ten parts water.
  • Protect yourself from contact with rat urine by wearing rubber gloves, especially if you have cuts or sores on your hands or arms.
  • Wash your hands with soap and warm water after any contact with areas where rats may live.
  • Always wear shoes whenever taking trash out.
  • When traveling to tropical regions, do not swim or wade in water that might contain animal urine.


See a health care provider if you think you have leptospirosis. You may need to take blood tests or start antibiotics.


Leptospirosis has been reported in dogs throughout the city. Ask your veterinarian if your dog should get vaccinated.

Symptoms of leptospirosis in dogs include:

  • Fever
  • Loss of appetite
  • Vomiting
  • Diarrhea
  • Severe weakness and depression
  • Stiffness
  • Muscle pain
  • Increased thirst and urination

If you think your pet may have leptospirosis, contact your veterinarian immediately.

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