What are the Leptospira species?
Leptospira species are bacterium that can be found in freshwater or soil contaminated with urine from infected animals. Leptospirosis is a disease caused by Leptospira bacteria, which enter the body and spread through the bloodstream, leading to infection that can affect multiple organs including the liver and kidneys.
According to the World Health Organization (WHO), it is a globally distributed zoonotic disease, meaning an infection that can be transmitted from animals to humans. It is most commonly associated with exposure to contaminated water or soil in tropical and subtropical environments. Infection occurs when bacteria enter the body through cuts in the skin, or through mucous membranes such as the eyes, nose, or mouth.
For Australian travellers, the risk is generally low in typical urban or resort settings, but increases with activities involving freshwater exposure, flooding, or close contact with animals or environments where rodent contamination may be present. It is also more likely to occur after heavy rainfall or natural disasters, when contaminated water spreads more widely into the environment.
FAQs
Which countries have a higher risk of leptospirosis?
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Leptospirosis is found worldwide, but the risk is higher in tropical and subtropical regions where warm temperatures and heavy rainfall allow the bacteria to survive longer in water and soil.
Higher-risk areas include parts of Southeast Asia (such as Thailand, Indonesia, the Philippines, and Vietnam), South Asia (including India and Sri Lanka), Pacific Island nations, Central and South America, and some regions of Africa.
Outbreaks can also occur after flooding in any country, including developed nations, when contaminated water spreads more widely. For Australian travellers, risk depends more on activities and environmental exposure than on country alone, particularly freshwater contact in rural or outdoor settings.
How do travellers usually get infected while overseas?
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Most infections occur when water or soil contaminated with leptospira species comes into contact with broken skin or mucous membranes such as the eyes, nose, or mouth.
This often happens during freshwater activities like swimming in rivers or lakes, rafting, kayaking, trekking through floodwater, or walking barefoot in wet environments. It can also occur through indirect exposure in areas where rodents or farm animals are present, particularly where sanitation is poor or flooding has recently occurred. Travel limited to hotels, cities, and well-maintained tourist areas is unlikely to result in infection.
What are the early warning signs I should look out for after travel?
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Early leptospirosis symptoms often appear suddenly and can look similar to common viral illnesses. Travellers may develop fever, chills, headache, and muscle aches, especially in the calves and lower back. It can also cause fatigue, nausea, vomiting, or red eyes. Because these symptoms are non-specific, they are sometimes mistaken for influenza or dengue. In some cases, symptoms can worsen after a few days and may involve jaundice, severe weakness, or breathing difficulties, which require urgent medical attention.
How serious is leptospirosis and what should I do if I think I have it?
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Illness can range from mild and self-limiting to severe disease affecting organs such as the liver, kidneys, and lungs. Severe cases are uncommon but can be serious if not treated promptly.
If you develop flu-like symptoms during or after travel to a higher-risk country, especially after freshwater exposure or contact with animals, you should seek medical care and inform the doctor about your travel history. Early diagnosis is important because antibiotics are most effective when started early in the illness and can significantly reduce the risk of complications.
What to Know
Leptospirosis symptoms
Leptospirosis symptoms typically appear between 2 and 30 days after exposure, although most cases begin within 5 to 14 days. Illness can vary widely in severity, ranging from a mild flu-like illness to severe, life-threatening disease involving multiple organs.
In the early phase, symptoms are often non-specific and can easily be mistaken for other infections such as influenza or dengue. This stage commonly includes sudden fever, chills, severe headache, and muscle pain, particularly in the calves, thighs, and lower back. Other symptoms include fatigue, nausea, vomiting, and sometimes diarrhoea. Some people also develop red or bloodshot eyes, which can be a useful clinical clue.
In a smaller proportion of cases, the illness progresses to a more severe form involving yellowing of the skin and eyes, kidney impairment, liver inflammation, bleeding problems, chest pain, cough, and shortness of breath. Severe infection may also affect the brain, leading to confusion and other symptoms. Without treatment, leptospirosis can become a medical emergency.
Leptospirosis diagnosis and treatment
Doctors diagnose leptospirosis by combining your symptoms, travel history, and blood or urine tests. Because early symptoms often look like a regular viral illness such as flu, it is important to tell your doctor if you have recently travelled to a higher-risk country or had contact with freshwater, flooding, or animals.
Treatment involves antibiotics, which work best when started early in the illness. If the infection is mild, antibiotic tablets may be enough. These help clear the bacteria from the body and reduce the risk of the illness becoming more serious.
If the infection is more severe, treatment is usually given in hospital. This is because stronger antibiotics are needed intravenously through a drip, along with close monitoring. Patients may also receive fluids to prevent dehydration, regular blood tests to check kidney and liver function, and breathing support if the lungs are affected. Early medical care greatly improves recovery and reduces the risk of complications.
Leptospirosis prevention
Prevention of leptospirosis is focused on avoiding exposure to contaminated water, soil, and animal urine. Travellers should avoid swimming, wading, or rafting in freshwater rivers, lakes, or floodwater in regions where leptospirosis is known or outbreaks have been reported. Even water that appears clean can carry the bacteria, particularly after heavy rainfall or flooding events.
Protective clothing plays an important role in reducing risk during outdoor activities. Wearing closed footwear and long trousers helps prevent bacteria entering through small cuts or abrasions. Any breaks in the skin should be covered with waterproof dressings, especially when hiking or working in rural or wet environments. Hand hygiene is also important, particularly after contact with soil, animals, or outdoor water sources.
Travellers should also be aware that rodents are a key reservoir of infection globally, so environments with visible rodent activity or poor sanitation carry higher risk. Food and drink hygiene, while not the primary route of transmission, still supports overall infection prevention in higher-risk settings.
There is no routine vaccine available for Australian travellers, so prevention relies entirely on behavioural precautions and environmental awareness. For those undertaking high-risk occupational or adventure activities in endemic regions, personalised advice from a travel health professional is recommended before departure.