Leptospirosis

A bacterial infection you can catch from water, mud or soil fouled by animal urine. It often feels like the flu, it’s treatable with antibiotics, and acting early matters.

Quick answer: Leptospirosis is caused by Leptospira bacteria passed in the urine of rats, mice, cattle, pigs, dogs and other animals. It gets in through cuts or the eyes, nose or mouth, usually after contact with floodwater, mud or wet soil. Symptoms start 5 to 14 days later: sudden fever, bad headache, muscle pain (especially calves) and red eyes. A few people get very sick, with yellow skin, kidney failure or bleeding (Weil’s disease). Antibiotics work best when started early.

In the news. NT Health has reported a death from leptospirosis in the Top End in late October 2026, and 11 cases in the Northern Territory so far this year, four of whom needed intensive care. Our thoughts are with the family and community. The health message: if you get a fever after contact with water, mud or animals, see a doctor promptly and mention it.

How it spreads

• Animal urine carries the bacteria. Rats and mice are the classic source, but cattle, pigs (including feral pigs), dogs and native animals can carry it too.
• Floodwater, mud and wet soil: the bacteria survive best in warm, wet places. Cases rise after heavy rain, floods and cyclones.
• Way in: cuts, grazes and waterlogged skin, or splashes into the eyes, nose or mouth. Rarely, by drinking contaminated water.
• Not usually person to person.

Symptoms

Many infections cause mild or no symptoms. When symptoms come, they usually start suddenly, 5 to 14 days after exposure (range 2 to 30 days).

• Fever, chills and a severe headache
• Strong muscle pain, especially the calves, thighs and lower back
• Red eyes without discharge
• Nausea, vomiting, diarrhoea or tummy pain
• Sometimes cough, rash or sensitivity to light

It’s easily mistaken for flu, dengue or gastro, which is why mentioning water, mud or animal contact helps your doctor.

Severe illness (Weil’s disease). About 5 to 10 in 100 people with symptoms become severely ill, sometimes after a short spell of feeling better. Signs include:

• Yellow skin or eyes (jaundice)
• Passing little urine (kidney failure)
• Bleeding, bruising or coughing up blood
• Breathlessness
• Severe headache with a stiff neck (meningitis) or confusion

Severe leptospirosis needs hospital care, often intensive care. The US CDC estimates 5% to 15% of severe cases are fatal; older age and other health conditions raise the risk.

Who’s at risk

• Outdoor and animal work: dairy, banana and sugar cane farming, abattoirs and meatworks, vets, sewer workers, musterers.
• Hunting and handling animals or carcasses, such as feral pigs.
• Freshwater fun: swimming, rafting, kayaking and adventure races, especially after rain.
• Flood clean-up, gardening in wet soil, camping and bushwalking.
• In Queensland, men are notified about 5 times as often as women, and Aboriginal and Torres Strait Islander people about twice as often.

The Australian picture

• Leptospirosis is uncommon in Australia but is a notifiable disease. It’s most common in warm, wet areas: Queensland, north-eastern NSW and the Top End.
• Queensland recorded 76 cases in 2025, down from 151 in 2021. About 40% of its cases are in the Cairns and Hinterland region.
• Outbreaks tend to follow floods and cyclones. Researchers warn that more extreme rain and flooding may push risk further south.
• In the NT, health authorities have flagged rural Darwin, Katherine and Arnhem Land, especially around water and flooding.

Around the world

• More than 1 million cases and about 59,000 deaths a year (CDC estimate).
• Highest burden: South and Southeast Asia, Oceania (including Pacific Islands), sub-Saharan Africa, Latin America and the Caribbean.
• Outbreaks often follow heavy rain and floods, in Australia and overseas.
• Travellers: rafting, swimming in rivers and muddy adventure races are classic exposures. Ask a travel doctor before high-risk trips; some people are offered weekly preventive antibiotics.

Testing

• Blood tests: early on, a PCR test looks for the bacteria’s DNA; after about a week, antibody tests become useful.
• A second antibody test 2 to 4 weeks later is often needed to confirm it.
• Severe cases may also need urine tests, kidney and liver tests, a chest X-ray or a lumbar puncture.
• Your doctor may start treatment before results return.

Treatment

• Antibiotics, ideally started early. Milder illness is usually treated with tablets, such as doxycycline; severe illness with antibiotics through a drip in hospital, such as penicillin.
• Severe cases may need intensive care, including dialysis for kidney failure or breathing support.
• Most people recover, though some feel unwell or tired for a long time afterwards.

Prevention

• Don’t swim or wade in floodwater, and don’t swallow floodwater or untreated fresh water.
• Cover cuts and grazes with waterproof dressings.
• Wear boots and gloves for flood clean-up, gardening, farm work and hunting.
• Wash with soap and water after contact with animals, carcasses, mud or floodwater, and before eating or smoking.
• Control rats and mice around the home, and keep food covered.
• Boil or treat drinking water if supplies may be contaminated.
• Ask your vet about vaccinating dogs and cattle. There’s no human vaccine in Australia.

See a doctor if

• You get a fever, bad headache or muscle pain within a month of floodwater, mud, farm or animal contact. Mention the exposure.
• You’re not improving after a few days of a “flu”.

Get urgent help: call 000 (Australia) or your local emergency number, or go to the nearest emergency department, for yellow skin or eyes, passing little or no urine, coughing up blood or unusual bleeding, breathlessness, confusion, a stiff neck, or feeling faint. In Australia, healthdirect (1800 022 222) gives free nurse advice any time.

Evidence and more information

• Queensland Health: Leptospirosis, communicable disease control guidance (Queensland case numbers 2021–2025, risk groups, testing)
• NSW Health: Leptospirosis fact sheet
• healthdirect: Leptospirosis
• CDC Yellow Book: Leptospirosis (global burden, severe disease, travellers)
• NT Health media release via Mirage News, 5 November 2026: NT Health urges leptospirosis precautions
• ABC News, 5 November 2026: Leptospirosis death in the Top End

Updated 9 November 2026. General education, not personal medical advice. If you’re unwell, talk to your GP or call healthdirect.

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