Leptospires are bacteria that are often corkscrew-like or hook-shaped. The disease called leptospirosis causes flu-like symptoms in humans, but it can also lead to severe courses and even death.


Worldwide, mainly in moist environments such as mud, freshwater lakes, rice fields and the like. In water, these bacteria remain capable of reproduction for weeks.

Pathogen reservoir

Natural reservoir are mainly rats, mice, field hamsters, cattle, pigs and dogs.

Infection route

Humans can become infected with leptospires through minor skin lesions and mucosal contact when they come into contact with urine from infected animals or water contaminated with urine from infected animals.

Incubation period

Mostly five to 14 days or up to 30 days


The disease, called leptospirosis, begins with flu-like symptoms such as fever and muscle pain. Without therapy, the fever subsides after three to eight days, but then rises again. During this phase, headaches, meningitis, muscle aches, and conjunctival hemorrhages may occur. In severe cases, damage to the liver and kidneys occurs. The disease can last for more than three weeks; in severe forms, mortality is up to ten percent.


The disease is treated with antibiotics


There is an approved vaccine for some animals, but not for humans

Situation in Austria

Leptospirosis is a notifiable disease. On average, 10 to 30 people fall ill each year.

Leptospirosen in Österreich

Specialized information

Leptospires are gram-negative elongated bacteria of the spirochete order that can cause an infectious disease called leptospirosis. Leptospirosis is a zoonotic disease and numerous wild, farm, and domestic animals are susceptible to leptospires and transmission to humans is possible. Transmission usually occurs directly through the urine of infected animals or indirectly through contact with contaminated environments (e.g., water, soil). Leptospires enter the organism through small skin lesions as well as through the mucous membranes. After entry, leptospires primarily colonize the kidneys of their hosts and are excreted from there in the urine. Of the wild reservoir hosts, rodents - such as rats and mice - are the most important. In Vienna, about a quarter of all rats are carriers of the pathogen.

Warm and humid climatic conditions favor the probability and duration of survival of leptospires in the environment. Due to climate change, heavy rainfall and flooding events are on the increase. Coupled with the expected increase in temperature, this can lead to rising infection rates in humans and animals.

In Austria, leptospirosis is a seasonal disease that occurs more frequently in summer and (early) fall. Certain occupational groups such as canal workers, farmers, harvest workers, and people who work intensively with animals and animal products (veterinarians, slaughterhouse employees, hunters) are particularly at risk of contracting leptospirosis. In addition, some cases of illness are known to have occurred after sporting events associated with exposure to water and mud (e.g., triathlons). In humans, the clinical picture ranges from flu-like symptoms to liver and kidney inflammation and, in rare cases, can lead to death. In cattle, pigs, and small ruminants, leptospirosis can lead to subclinical courses of disease to severe reproductive disorders such as abortions, stillbirths, and the birth of low-life offspring and decline in milk production.

Despite the relevance of the pathogen for human and animal health and the economic impact, we assume that leptospirosis is currently one of the underdiagnosed diseases. The reason for this is the often unspecific expression of symptoms, which can be caused by a number of other pathogens or go completely unnoticed.


Antibody detection is often used to detect leptospiral infections. The gold standard method for humans and animals is the microagglutination test (MAT). This test, as well as the genome detection (PCR), is performed at the IVET Mödling of the AGES for the clarification of suspected cases as well as in the context of projects.

Projects are currently underway to isolate leptospiral strains occurring in Austria in order to further improve diagnostics and generate data on leptospiral occurrences.


Institut für veterinärmedizinische Untersuchungen Mödling

Last updated: 25.05.2023

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