A group of infections transmitted to humans by rats and other animals
Infections caused by different types of Leptospira bacteria are known generally as leptospirosis. The bacteria are carried by animals such as rats or foxes and excreted in their urine. The infection is usually transmitted to humans by contact with water or soil contaminated by infected urine. In most cases the infection causes a flu-like illness. However, in its most severe form, which is known as Weil’s disease, leptospirosis may be life-threatening.
Leptospirosis most commonly occurs in farmers and sewage workers, but the disease can affect anyone who comes into contact with contaminated water, such as swimmers or those taking part in watersports.
The symptoms of leptospirosis usually appear abruptly 7–12 days after infection but can appear at any time from 2–30 days. They may include:
Intense headache and muscle pain.
Flat, red rash.
Inflammation of the eyes and eyelids (see Conjunctivitis).
The symptoms tend to disappear after a few days but may recur if immediate treatment is not given. If the disease goes untreated, it frequently causes a potentially dangerous inflammation of the membranes covering the brain (see Meningitis).
About 1 in 10 infected people develops Weil’s disease. This disorder leads to widespread internal bleeding, damage to the kidneys and liver, and jaundice, which causes the skin and the whites of the eyes to turn yellow.
To diagnose leptospirosis, your doctor may arrange for blood and urine tests to check for the presence of bacteria. If treated with antibiotics at an early stage, most people recover fully.
As a preventive measure, workers at particular risk of infection are usually given antibiotics after minor injuries such as cuts and scrapes.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.