Leptospirosis is an acute illness caused by the Leptospira bacteria, of which there are over 200 different types.
How it is spread
The bacteria can be found in both domestic and wild animals, including pigs, cattle, rats, dogs, possums, bats, deer and foxes. Rats are considered the most important source of leptospirosis worldwide.
Humans can become infected with the bacteria through contact with water, wet soil or vegetation that is contaminated with the urine of infected animals. Cuts or grazes in people’s skin or splashes of infected fluid to the eye increase the risk of infection.
The bacteria may be excreted in the urine of infected people, however the disease is rarely passed from person to person.
Where the disease is found
Leptospirosis occurs worldwide. In the Northern Territory (NT) the Fogg Dam / Harrison Dam area outside of Darwin is home to a large population of the native ‘dusky rat’ (Rattus colletti), and people are known to have become infected in this area.
Other areas associated with cases include Oenpelli, Finniss River, rural Darwin and Katherine district but generally areas around water, especially after flooding, are risk areas. In the NT there are usually 1-4 cases notified per year.
Symptoms generally occur 10 days after exposure, but may range from 4 to 19 days. The illness lasts from a few days to 3 weeks or longer.
The initial symptoms usually include a sudden onset of fever with headaches, chills, severe muscle pain (particularly in the legs) and reddened eyes. Sometimes cough, diarrhoea and vomiting can also occur.
Some people with leptospirosis will go on to develop more severe disease (called Weil’s disease) with symptoms including jaundice (yellow skin or eyes), bleeding, breathing difficulties and confusion.
In rare cases leptospirosis can be fatal however most people who are infected have mild symptoms that resolve without complications, or have no symptoms at all.
Who is at risk
People at risk are those who have close contact with animals or who are exposed to water, mud, soil or vegetation that has been contaminated with animal urine. Occupations associated with increased risk of infection are abattoir workers, farmers, veterinarians, rice and sugarcane field workers. Some recreational activities also increase the risk of exposure and include camping, bushwalking, gardening, white water rafting, kayaking and hunting.
A number of cases in the NT have been in turtle and duck/goose hunters and in those working with crocodiles, including crocodile egg collecting.
Prompt specific antibiotic treatment, as early as possible in the illness is essential.
The antibiotics used may include penicillin or doxycycline as determined by a doctor. Antibiotics given early in the illness are effective in reducing the likelihood of developing severe disease. Other treatments are supportive and aimed at minimising the impact of any complications that may arise.
There is no human vaccination against leptospirosis. Vaccinations are available for dogs, cattle and pigs against some strains of leptospira.
The public, employers and those working in hazardous occupations need to be aware of the disease and the way it is spread. In some instances preventative antibiotics may be considered after discussion with infectious disease/public health physicians.
Personal protective measures
To help protect yourself against leptospirosis you can do the following:
- avoid swimming or wading in water that may be contaminated
- cover all cuts or abrasions with waterproof dressings
- thoroughly wash hands and arms in soapy water after handling animals or carcasses, or after coming into contact with liquids that may be contaminated
- shower thoroughly after contact with potentially contaminated water or soil
- avoid hand to mouth, nose to eye contact (and especially smoking) while handling animals that may be infected
- wash and dry hands before smoking or eating
- wear gloves, eye shields, aprons and boots at all times when handling animals or liquids contaminated with the urine of animals
- prevent contamination of living and recreational areas with the urine of infected animals, including keeping working dogs out of the house yard
- control rodents by removing rubbish and food sourced from close to housing
- do not feed dogs raw offal or feral meat because this may infect them.
For more information contact your nearest Centre for Disease Control.
Last updated: 22 March 2019