Leptospirosis Facts

  • Leptospirosis is an infectious disease caused by a bacterium.
  • Leptospirosis is transmitted to humans by direct exposure to urine or tissue of an infected animal.
  • Leptospirosis typically progresses through two phases of nonspecific symptoms.
  • Leptospirosis can be diagnosed by culture of infected blood, urine, or spinal fluid, as well as using antibody testing.
  • Your pets may also be at risk for contracting the leptospirosis bacterium.
  • Leptospirosis is treated with antibiotics and is rarely fatal.
  • In the aftermath of Hurricane Maria, several deaths were reported in Puerto Rico from leptospirosis.

What Are the Signs and Symptoms of Leptospirosis?

The illness typically progresses through two phases:

  • The first phase of nonspecific flu-like symptoms includes headaches, muscle aches, eye pain with bright lights, followed by chills and fever. Watering and redness of the eyes occur and symptoms seem to improve by the fifth to ninth day.
  • The second phase begins after a few days of feeling well. The initial symptoms recur with fever and aching with the stiffness of the neck. Some patients develop serious inflammation of the nerves to the eyes, brain, spinal column (meningitis), or other nerves. Right upper area abdominal pain may occur. Less common symptoms relate to disease of the liver, lungs, kidneys, and heart.

Leptospirosis associated with liver and kidney disease is called Weil's syndrome and is characterized by yellowing of the eyes (jaundice). Patients with Weil's syndrome can also develop kidney disease and have more serious involvement of the organs affected.

What Causes Leptospirosis?

  • Leptospirosis is an infectious disease caused by a type of bacteria called a spirochete of various species of the genus Leptospira.
  • Leptospirosis bacterial infection can be transmitted by many animals such as rats and other rodents, skunks, opossums, raccoons, foxes, and other vermin.
  • The Leptospira bacteria is transmitted through contact with infected soil or freshwater.
  • The soil or water is contaminated with the waste products of an infected animal.
  • People contract the disease by either ingesting contaminated food or water, by the broken skin, or mucous membranes (eyes, nose, sinuses, or mouth) come into contact with the contaminated water or soil.
  • Leptospirosis occurs worldwide, but it is most commonly acquired in the tropics and areas with heavy rainfall.
  • The U.S. Centers for Disease Control and Prevention states 100-200 cases of leptospirosis are reported each year in the United States, with about 50% of cases occurring in Hawaii.
  • Although the incidence in the United States is relatively low, leptospirosis is considered the most widespread disease that is transmitted by animals in the world.

In 2017, Hurricane Maria hit the island of Puerto Rico. In the following weeks, deaths were reported due to infection from leptospirosis. A 2010 outbreak in Michigan caused serious illness in numerous pets, raising concern for the local human population. In 2009, typhoons hit the Philippines, causing a leptospirosis outbreak. The Philippines Department of Health then reported 1,887 cases of leptospirosis, which resulted in 138 deaths.

What Are Risk Factors for Leptospirosis?

  • Veterinarians, pet shop owners, sewage workers, and farm employees are at particularly high risk due to occupational exposure.
  • Other risk factors for getting leptospirosis include participating in outdoor sporting activities like swimming, triathlons, canoeing, rafting, hiking, and camping, where people can come into contact with contaminated water or soil.

What Is the Incubation Period for Leptospirosis?

  • Leptospirosis symptoms begin from two to 25 days after initial direct exposure (the incubation period) to the urine or tissue of infected rodents and other animals.
  • This can even occur via contaminated soil or water.

How Do Health Care Professionals Diagnose Leptospirosis?

  • The diagnosis of leptospirosis is made by culture of the bacterial organism Leptospira from infected blood, spinal fluid, or urine.
  • Blood tests that indicate rising Leptospira antibody levels in the blood can aid in making the diagnosis, as the technique required to perform the culturing is delicate and difficult.

What Is the Treatment and Prognosis for Leptospirosis?

The treatment of leptospirosis involves high doses of antibiotics. Antibiotic treatment (doxycycline [Vibramycin, Oracea, Adoxa, Atridox], penicillin) is most effective when initiated early in the course of the illness. Severely ill patients may need hospitalization for IV fluid and antibiotic treatment. Severe liver manifestations and kidney damage and even failure resulting from the infection may require intensive medical care and sometimes dialysis treatment. In the severe form of the disease, liver and kidney function often does return to normal after recovery from the illness.

Mortality rates for severe disease with leptospirosis can range from 1%-5%, depending on the severity of organ dysfunction and the patient's general health prior to infection. Most previously, healthy patients have a good prognosis and will make a full recovery.

Is There a Vaccine for Leptospirosis?

  • A vaccine for human leptospirosis infection is available and used in some countries in Europe and Asia.
  • It must be given every year like a flu shot.
  • A longer-acting leptospirosis vaccine is being investigated in Cuba. It is not currently available in the United States.
  • Travelers who are going to an area where leptospirosis is common and who will be engaged in activities that increase the likelihood of exposure can take 200 mg of doxycycline per week by mouth starting before and during the time period of potential exposure.
  • Leptospirosis was a reportable disease in the United States, but it was removed from the national CDC list of reportable diseases. It is, however, still reportable in some states, most notably Hawaii.

There is a leptospirosis vaccine available for dogs that can prevent leptospirosis and protect dogs for at least 12 months. A veterinarian may recommend vaccination for at-risk dogs.

What Is Leptospirosis in Pets?

According to information from the CDC, your pets (especially dogs, less commonly cats) can contract leptospirosis. Your pet can contract it in the same ways you can (ingesting contaminated soil, water, or through skin wounds). Infected dogs, cats, and other pets may exhibit

If you suspect your pet is ill, take them to a veterinarian for testing and treatment. Early antibiotic treatment often can limit or prevent organ damage.

If your pet is diagnosed with leptospirosis, you must be careful to try to prevent exposure to yourself or other household members. Remember to wash your hands frequently with soap and water after cleaning up waste from your pet. If possible, use latex or rubber gloves to do the job of cleanup. Use a diluted (1:10 parts) bleach solution to clean surfaces where pet wastes may have contaminated. And make sure your pet receives the full course of antibiotic treatment that is prescribed by your vet. Discuss other pet care issues directly with your vet should you have any other questions regarding the disease.

Leptospirosis Symptom


Low-grade fevers range from about 100 F-101 F; 102 F is intermediate grade for adults but a temperature at which adults should seek medical care for an infant (0-6 months). High-grade fevers range from about 103 F-104 F. Dangerous temperatures are high-grade fevers that range from over 104 F-107 F or higher (extremely high fevers are also termed hyperpyrexia). The preceding fever values may vary somewhat according to the condition and age of the patient, but they offer a reader a way to judge the terms "low," "high," and "dangerous" when they are used in reference to fever in the medical literature.

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Brett-Major, D.M. and R. Coldren. "Antibiotics for leptospirosis." The Cochrane Database of Systematic Reviews 2 Feb. 15, 2015. <https://www.ncbi.nlm.nih.gov/pubmed/22336839>.

Martinez, R., et al. "Efficacy and Safety of a Vaccine Against Human Leptospirosis in Cuba." Rev Panam Salud Publica. 15.4 Apr. 2004: 249-255. <http://www.ncbi.nlm.nih.gov/pubmed/15193180>.

Soucheray, Stephanie. "Groups warn of infectious disease threats in Puerto Rico." Center for Infectious Disease Research and Policy. Oct. 12, 2017. <http://www.cidrap.umn.edu/news-perspective/2017/10/groups-warn-infectious-disease-threats-puerto-rico>.

Spickler, A.R., and K.R. Leedom Larson. "Leptospirosis." August 2013. <http://www.cfsph.iastate.edu/Factsheets/pdfs/leptospirosis.pdf>.

"Treatment of Acute Human Leptospirosis - Professional Guide." The Leptospirosis Information Center. <http://www.leptospirosis.org/topic.php?t=38>.

United States. Centers for Disease Control and Prevention. "Leptospirosis." Oct. 12, 2005. <http://www.cdc.gov/ncidod/dbmd/diseaseinfo/leptospirosis_g.htm>.

United States. Centers for Disease Control and Prevention. "Leptospirosis: Risk of Exposure." June 9, 2015. <https://www.cdc.gov/leptospirosis/exposure/index.html>.