Leptospirosis is a type of bacterial infection spread by animals. It is caused by a strain of bacteria called leptospira.

In 90% of cases, leptospirosis only causes mild flu-like symptoms, such as headache, chills and muscle pain.

However, in some cases the infection is more severe and can cause life-threatening problems, including organ failure and internal bleeding. In its most severe form, leptospirosis is also known as Weil's disease.

The common mild symptoms mean that most leptospirosis infections are hard to diagnose. Diagnosis is easier if the infection causes more serious problems.

A detailed history of places you have been and any animals you have been in contact with can help with a diagnosis.

Read more about the symptoms of leptospirosis and diagnosing leptospirosis.

Why does leptospirosis happen?

Leptospirosis is spread to humans by animals.

You can catch leptospirosis by touching soil or water contaminated with the urine of wild animals infected with the leptospira bacteria.

Animals known to be carriers of the leptospira bacteria include cattle, pigs, dogs and rodents, particularly rats.

Although the condition is uncommon in the UK, people who regularly deal with animals, such as farmers and vets, have a higher risk of developing leptospirosis.

You may also be at a higher risk if you frequently come into contact with sources of freshwater, such as rivers and lakes. This might be because of your occupation or through taking part in recreational activities such as water sports and fishing.

Transmission between humans is incredibly rare.

Read more about the causes of leptospirosis.

Cases in the UK

Leptospirosis is rare in the UK. For example, only 44 cases were reported in England and Wales during 2011. Of these, 15 cases originated overseas and none were fatal.

Most of the people affected either worked with livestock or contracted the condition from sewage or freshwater sources.

Can leptospirosis be prevented?

The risk of contracting leptospirosis in the UK is so low that you don't need to take drastic measures to avoid the condition.

If you work with animals  dead or alive  or are in regular contact with freshwater sources, you can help protect yourself from leptospirosis by wearing appropriate protective clothing and by cleaning and dressing wounds.

This advice is particularly useful if you are travelling to an area where leptospirosis is more common.

Read more about preventing leptospirosis.

How is leptospirosis treated?

Leptospirosis is treated with a course of antibiotics.

For mild forms of leptospirosis, antibiotic tablets that can be taken at home are usually used for about a week.

Most people with more severe leptospirosis will require admission to hospital so the functions of their body can be supported while the underlying infection is treated with injections of antibiotics.

Read more about treating leptospirosis.

Global impact of leptospirosis

Leptospirosis is more common in tropical areas of the world.

Globally, it is estimated that 7-10 million people get leptospirosis every year. It is difficult to estimate exactly how many people die from leptospirosis because many cases occur in parts of the developing world where causes of death are not routinely reported.

It is anticipated that the number of cases of leptospirosis will continue to increase in the future as a result of global warming and the expected increase in flooding.

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Page last reviewed: 07/11/2012

Next review due: 07/11/2014