World's Most Widespread Zoonotic Disease Poses New Risks

Focus on Leptospirosis

CDC Division of High-Consequence Pathogens and Pathology (DHCPP)


June 17, 2013

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In This Article

Leptospirosis: The Most Widespread Zoonotic Disease

Emerging diseases are always a concern for clinicians. But, in addition to new diseases, existing diseases may sometime reemerge as significant public health threats. New information tells us that this may be the case with leptospirosis.

Leptospirosis is a bacterial disease that affects humans and animals. Caused by bacteria of the genus Leptospira, it is considered the most widespread zoonotic disease in the world and is most commonly found in tropical or temperate climates.

The disease is spread through the urine of infected wild and domestic animals, including dogs, cattle, pigs, horses, and rodents. People can get the disease when they are exposed to the urine of infected animals or soil, water, or food contaminated with the urine of infected animals.

In humans, leptospirosis can cause a wide range of symptoms, but it usually presents as an acute febrile illness that might be mistaken for other diseases. Some infected persons, however, have no symptoms at all.

Although some diseases can be prevented through vaccination, there is no human leptospirosis vaccine licensed for use in the United States. When infection occurs, however, antibiotics (such as doxycycline or penicillin) can provide effective treatment. For maximum effectiveness, antibiotics should be given early in the course of the disease. Without treatment, leptospirosis can lead to kidney damage, meningitis, liver failure, respiratory distress, and even death.