Leptospirosis
A bacterial infection caught from water or soil contaminated by animal urine
Quick Facts
- Type: Bacterial infection (zoonotic)
- Spread by: Contaminated water, soil, or animal urine
- Range: Mild flu-like illness to severe organ disease
- Treatment: Antibiotics, especially when started early
Overview
Leptospirosis is an infection caused by bacteria of the Leptospira group. It is a zoonotic disease, meaning it spreads from animals to people. Many animals, including rodents, dogs, cattle, and pigs, can carry the bacteria in their kidneys and shed them in their urine, contaminating water and soil. People usually become infected when contaminated water or soil contacts broken skin, the eyes, nose, or mouth.
The illness ranges widely in severity. Many people have a mild, flu-like sickness or no symptoms at all, while a smaller number develop a severe form, sometimes called Weil disease, that can damage the kidneys, liver, lungs, and other organs. Leptospirosis is more common in warm, wet climates and after flooding, and it responds well to antibiotics, especially when treatment starts early.
Symptoms
Symptoms usually begin about 1 to 2 weeks after exposure and can come in two phases. Early, mild illness may include:
- High fever and chills
- Severe headache
- Muscle aches, especially in the calves and lower back
- Red eyes
- Nausea, vomiting, or diarrhea
In severe cases, after a brief improvement, more serious symptoms can develop:
- Yellowing of the skin and eyes (jaundice)
- Reduced urination or kidney failure
- Difficulty breathing or coughing up blood
- Bleeding and severe weakness
Severe leptospirosis is a medical emergency.
Causes
Leptospirosis is caused by Leptospira bacteria, which are carried by many wild and domestic animals and passed in their urine. People become infected through:
- Contaminated water or soil: Swimming, wading, or working in water or mud contaminated by animal urine, particularly after heavy rain or flooding.
- Direct contact: With the urine or tissues of infected animals.
- Entry points: The bacteria enter through cuts or scrapes, or through the lining of the eyes, nose, or mouth.
Person-to-person spread is rare. The bacteria can survive for weeks to months in warm, moist environments.
Risk Factors
- Occupations with animal or water contact, such as farming, veterinary work, sewer work, and slaughterhouse work
- Outdoor recreation in fresh water, such as swimming, kayaking, or hiking through flooded areas
- Living in or traveling to warm, tropical regions
- Exposure to flooding
- Contact with rodents or with pets that may carry the bacteria
Diagnosis
Because early leptospirosis resembles many other infections, diagnosis relies on history and laboratory testing:
- Exposure history: Recent contact with potentially contaminated water, soil, or animals.
- Blood tests: To detect antibodies to the bacteria or the bacteria themselves, and to assess kidney and liver function.
- Urine tests: May detect the bacteria in some stages of illness.
Treatment is often started based on suspicion before tests are complete, since early antibiotics work best.
Treatment
Leptospirosis is treated with antibiotics, and care is more intensive in severe cases:
- Antibiotics: Such as doxycycline for milder illness, or intravenous antibiotics like penicillin or ceftriaxone for severe disease. Starting early gives the best results.
- Supportive care: Fluids, fever control, and rest.
- Hospital care for severe cases: Treatment of kidney failure (sometimes including dialysis), breathing support, and management of bleeding and other organ problems in an intensive care setting.
Most people recover fully, especially when the illness is mild or treated promptly.
Prevention
- Avoid swimming or wading in water that may be contaminated, especially after flooding
- Cover cuts and broken skin with waterproof dressings before water or soil contact
- Wear protective clothing, gloves, and boots for at-risk work
- Control rodents around homes and workplaces
- Keep pets vaccinated where appropriate and avoid contact with animal urine
- Consider preventive antibiotics for short, high-risk exposures only on medical advice
When to See a Doctor
See a doctor if you develop fever, severe muscle aches, headache, or red eyes after contact with fresh water, soil, or animals, particularly after flooding or travel to a tropical area. Seek emergency care right away for warning signs of severe illness:
- Yellowing of the skin or eyes
- Reduced urination
- Difficulty breathing or coughing up blood
- Confusion, severe weakness, or signs of bleeding
Frequently Asked Questions
How do people catch leptospirosis?
Most people are infected through contact with water or soil contaminated by the urine of infected animals, often after flooding or during water-based work or recreation. The bacteria enter through cuts, or through the eyes, nose, or mouth.
Is leptospirosis contagious between people?
Person-to-person spread is rare. The infection almost always comes from contact with contaminated water, soil, or animal urine rather than from another person.
What are the early signs of leptospirosis?
Early symptoms often resemble the flu, with high fever, chills, severe headache, muscle aches (especially in the calves), and red eyes. These usually start about one to two weeks after exposure.
Is leptospirosis serious?
Many cases are mild, but a smaller number progress to a severe form that can damage the kidneys, liver, and lungs and cause bleeding. Severe leptospirosis is a medical emergency requiring hospital care.
How is leptospirosis treated?
It is treated with antibiotics such as doxycycline for milder illness or intravenous antibiotics for severe cases. Starting treatment early gives the best chance of a full recovery, and severe cases need hospital support.
References
- Centers for Disease Control and Prevention (CDC). Leptospirosis.
- World Health Organization (WHO). Leptospirosis.
- Mayo Clinic. Leptospirosis.
- MedlinePlus, U.S. National Library of Medicine. Leptospirosis.