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It is possible that the main title of the report Leptospirosis is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • Canefield Fever
  • Canicola Fever
  • Field Fever
  • Mud Fever
  • Seven Day Fever, Leptospirosis
  • Spirochetosis
  • Swineherd Disease

Disorder Subdivisions

  • None

General Discussion

Leptospirosis is an infectious disease that affects humans and animals. It results in a wide range of symptoms, and some people may have no symptoms at all. It is caused by a spiral-shaped bacterium (spirochete). Symptoms include high fever, chills, muscle aches, headache, vomiting, diarrhea, and jaundice (yellow skin and eyes).

A definitive diagnosis requires laboratory testing of a blood or urine sample. Early detection is important because the disease can cause serious complications if not treated early in its course. These include kidney damage (nephrosis), meningitis (inflammation of the tissue around the brain or spinal cord), respiratory distress and/or liver failure.


The symptoms of leptospirosis vary considerably. Some people may experience no symptoms at all. Some may experience moderate or more severe flu-like symptoms. Some may experience very serious complications if the disease is not treated.

The disorder characteristically occurs in two phases. The septocemic phase starts abruptly with headache, pain behind the eyeball (retroorbital), lack of appetite (anorexia), severe muscle aches, chills, sweating, nausea, vomiting, and fever. Constipation, diarrhea, symptoms of the common cold, coughing, chest pain, a stiff neck, and difficulty breathing (dyspnea) may also occur. Enlargement of the spleen (splenomegaly) and liver (hepatomegaly) are uncommon, but may occur. This phase usually lasts four to nine days, with recurrent chills and fever that spikes to over 39 degrees C (102 F), and then abates.

The sixth to 12th day of illness marks the immune (or second) phase of leptospirosis. Antibodies appear in the blood serum. Fever and earlier symptoms may recur, and symptoms of irritated membranes lining the brain (meninges) may develop. Examination of the cerebrospinal fluid after the seventh day shows a greater than normal number of cells (pleocytosis) in at least 50 percent of patients. Inflammation of the iris and the ciliary body behind the iris (iridocyclitis), the optic nerve (optic neuritis), and peripheral disease of the nerves (neuropathy) may occur infrequently. If acquired during pregnancy, leptospirosis may cause abortion, even during the period of convalescence.


Humans usually become infected through contact with water, food or soil containing urine from infected animals. The bacterium associated with the disease, Leptospira, can be found in the urine of many different animals, such as dogs, cats, cattle, horses, pigs, and, especially, rodents. The disease is transmitted to humans when infected urine enters the body when one swallows contaminated food or water or through breaks in the skin or contact with mucosal surfaces such as the eyes or nose. The disease is not known to be spread from person to person.

The usual period of time between exposure to the bacterium and appearance of the disease is from two to 20 days.

Affected Populations

While leptospirosis is rare in the United States, it is common through tropical and semitropical regions. It can affect individuals of all ages. At least 75 percent of individuals with leptospirosis are male, mainly because workers in jobs that are at risk of the infection are more often held by males.

The infection is an occupational disorder affecting farmers, veterinarians, workers in slaughter houses and sewer workers. However, many affected individuals are thought to be exposed incidentally during recreational activities, such as swimming in water contaminated by the urine of infected animals.

In recent years, several cases of leptospirosis have been reported in urban areas, especially inner city neighborhoods. It is thought that these areas are infested with rats that carry the infection.

Standard Therapies


Diagnosis may be made during the early stage of the infection (days 1-7) by culturing the Leptospira bacterium from body fluids. From days 4 through 10, the cerebrospinal fluid is cultured, and after day 10, the patient's urine may be cultured. There are other tests of the blood and immune system that may be performed.


Leptospirosis is treated with antibiotics such as penicillin, oral doxycycline, streptomycin, chloramphenicol, and erythromycin.

Mechanical ventilation has been used successfully in treating respiratory distress in leptospirosis patients.

Peritoneal dialysis in combination with treatment with antibiotics has been used successfully to treat severe liver and kidney failure in patients with leptospirosis.


The risk of infection may be greatly reduced by not swimming in waters that may be contaminated with animal urine. People who work in jobs where this might be an occupational hazard, should wear appropriate protective clothing to avoid skin contact if possible. Pet-owners should be aware of the possibility of infection of household pets.

Investigational Therapies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:




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Tappero JW, Ashford DA, Perkins BA. Leptospirosis. In: Mandell GL, Bennett JE, Dolan R. Eds. Mandell, Douglas and Bennett's Principles and Practice of Infectious Diseases. 5th ed. Churchill Livingstone Inc. New York, NY; 2000:2495-501.


Sitprija V, Losuwanrak K, Kanjanabuch T. Leptospiral nephropathy. Semin Nephrol. 2003;23:42-48.

Carvalho CR, Bethlem EP. Pulmonary complications of leptospirosis. Clin Chest Med. 2002;23:469-78.

Vinetz JM. Leptospirosis. Curr Opin Infect Dis. 2001;14:527-38.

Jones S, Kim T. Fulminant leptospirosis in a patient with human immunodeficiency virus infection: case report and review of the literature. Clin Infect Dis. 2001;33:E31-33.

Kobayashi Y. Clinical observation and treatment of leptospirosis. J Infect Chemother. 2001;7:59-68.

Mahy BW, Brown CC. Emerging zoonoses: crossing the species barrier. Rev Sci Tech. 2000;19:33-40.

Guidugli F, Castro AA, Atallah AN. Antibiotics for preventing leptospirosis. Cochrane Database Syst Rev. 2000:CD001305.


Leptospirosis. CDC. Division of Bacterial and Mycotic Diseases. Last reviewed March 7, 2003. 3pp



Leptospirosis. Health & Safety Executive. nd. 2pp.


Leptospirosis. New York State Department of Health, Communicable Disease. Revised: March 2003. 2pp.


Leptospirosis. State of Wisconsin, Department of Health & Family Services. Last Revised: July 02, 2001.


Leptospirosis. Association of State and Territorial Directors of Health Promotion and Public Health Education (ASTDHPPHE). Nd. 3pp.



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For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into myCigna.com. For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html.