Leptospirosis

Leptospirosis is a common infectious disease in tropical and subtropical regions. It is caused by a water-borne bacteria and is therefore more common in areas with high rainfall. 

The bacteria is spread through the urine of infected animals including rodents, dogs, pigs, cattle and horses. Feral animals can also be a source. Once in the soil, the bacteria can survive for many months. Animals carrying the disease can look perfectly well. Humans become infected through contact with contaminated water or soil. Outbreaks of the disease often occur during local environmental disasters such as floods, cyclones or earthquakes.

The disease is more likely to be found in low and low middle income countries where investment in public health infrastructure is low. Most cases in SE Asia have been reported in India, Indonesia, Thailand and Sri Lanka during the wet season, The disease is very under reported. Cases can be confused with dengue fever, typhoid, viral hepatitis.

Leptospirosis has occupational risk in many settings. These include:

• Water and sanitation
• Agriculture
• Mining
• Abattoirs
• Dairy
• Veterinary

Risk generally occurs with exposure to water. This includes swimming in fresh water close to urban farming environments or participating in recreational water sports such as kayaking or rafting. Exposure may also occur with jungle trekking and camping. Foreign volunteers or humanitarian workers in less developed countries may be at greater risk through their work in agricultural enterprises, water management or animal husbandry.

A study from the Netherlands provides some insight into traveller risk. Data was collected for the period 2009 to 2016. A total of 224 cases were reported. A majority of cases were in males (78.1%) and 62.1% had travelled to SE Asia. Over 50% were hospitalized and there were no fatalities. Of note also, were cases from France, Belgium, Bulgaria, Luxembourg, Slovakia and Slovenia. The authors also reported 41 cases of leptospirosis from the Netherlands.

They concluded that Leptospirosis is an increasing risk for travellers and probably underreported (antibiotic treatment with no diagnosis). Treating physicians of returned travellers should have a low threshold for diagnostic testing.

For more detailed information, see the WHO fact sheet