Leptospirosis (Weil’s disease)

Leptospirosis (Weil’s disease) is an infection caused by corkscrew- shaped bacteria called Leptospira interrogans. The bacteria occur worldwide and many different serotypes are known. Serotype refers to groups of microorganisms that are extremely closely related, but can be distinguished by having slightly different antigens (a foreign substance which causes the body to produce antibodies) or causing the body to produce slightly different antibodies.

How leptospirosis is spread

People get leptospirosis by contact with fresh water, wet soil or vegetation contaminated by the urine of infected animals, especially:

• Rodents (for example rats and mice)
• Cattle
• Pigs
• Horses
• Dogs

Both domestic and wild animals can carry leptospirosis and they pass the bacteria in their urine.

The Leptospira bacteria can enter the body through broken skin, water-softened skin, mucous membranes (the thin moist lining of many parts of the body such as the nose, mouth, throat and genitals) or by swallowing or inhaling contaminated water.

Leptospirosis is an occupational hazard for many people working outdoors or with animals, such as:

• Dairy farmers
• Sewer workers
• Veterinarians
• Abattoir workers
• Military personnel.

Campers and people who participate in outdoor sports such as white water rafting, swimming or wading in contaminated lakes or rivers are also at risk.

Signs and symptoms

Symptoms of infection with Leptospira may range from no symptoms to fatal disease. The illness often occurs in 2 phases.

First phase

The first phase, which usually lasts 5 to 7 days, begins suddenly with symptoms including:

• high fever
• vomiting
• diarrhoea
• red eyes
• muscle aches (especially thigh and calf muscles)
• rash
• chills

Second phase

A second phase of illness (immune phase) may follow 1 to 2 weeks later, with symptoms such as:

• jaundice (yellowing of the skin and eyes)
• kidney failure
• irregular heart beat
• lung problems
• meningitis (inflammation of the lining of the brain)
• red eyes.

Diagnosis

Diagnosis is difficult but is usually made by blood and urine tests. Early in the illness theLeptospira bacteria may be grown from blood or urine, though they take a long time to grow.

 Prevention

• Exclusion from childcare, preschool, school or work is not necessary.
• Minimise contact with fresh water, mud and vegetation that might be contaminated with the urine of infected animals, especially rodents. Wear protective clothing, such as waterproof boots or waders, when participating in recreational or work activities that might result in such exposure.
• Vaccinate dairy cows.
• Rodent control is important.
• No vaccine is available for humans.