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Leptospirosis is an infection that occurs when you come in contact with Leptospira bacteria.

Causes of Leptospirosis

The Leptospira bacteria can be found in fresh water that has been contaminated by animal urine. The infection occurs in warmer climates.

Leptospirosis is not spread from person to person, except in vary rare cases. It occasionally spreads through sexual intercourse, breast milk, or from a mother to her unborn child.

Risk factors include:

  • Occupational exposure -- farmers, ranchers, slaughterhouse workers, trappers, veterinarians, loggers, sewer workers, rice field workers, and military personnel
  • Recreational activities -- fresh water swimming, canoeing, kayaking, and trail biking in warm areas
  • Household exposure -- pet dogs, domesticated livestock, rainwater catchment systems, and infected rodents

Leptospirosis is rare in the continental United States. Hawaii has the highest number of cases in the United States.

Leptospirosis Symptoms

Symptoms can take 2 to 26 days (average 10 days) to develop, and may include:

  • Dry cough
  • Fever
  • Headache
  • Muscle pain
  • Nausea, vomiting, and diarrhea
  • Shaking chills

Less common symptoms include:

  • Abdominal pain
  • Abnormal lung sounds
  • Bone pain
  • Conjunctivitis
  • Enlarged lymph glands
  • Enlarged spleen or liver
  • Joint aches
  • Muscle rigidity
  • Muscle tenderness
  • Skin rash
  • Sore throat

Tests and Exams

The blood is tested for antibodies to the bacteria.

Other tests that may be done:

Treatment of Leptospirosis

Medications to treat leptospirosis include:

Complicated or serious cases may need supportive care or treatment in a hospital intensive care unit (ICU).

Prognosis (Outlook)

The outlook is generally good. However, a complicated case can be life threatening if it is not treated promptly.

Potential Complications

  • Jarisch-Herxheimer reaction when penicillin is given
  • Meningitis
  • Severe bleeding

When to Contact a Health Professional

Contact your health care provider if you have any symptoms of, or risk factors for, leptospirosis.

Prevention of Leptospirosis

Avoid areas of stagnant water, especially in tropical climates. If you are exposed to a high risk area, taking doxycycline or amoxicillin may decrease your risk of developing this disease.


Ko AI. Leptospirosis. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 331.

Levett PN, Haake DA. Leptospira species (leptospirosis). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2009:chap 240.

World Health Organization, International Leptospirosis Society. Human leptospirosis guidance for diagnosis, surveillance, and control, 2003.

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Review Date: 8/17/2014
Reviewed By: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
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