What is Leishmaniasis?

Leishmaniasis is a disease caused by a protozoa and spread by the bite of infected sand flies. It is estimated that 12 million people are infected worldwide and 2 million new cases occur annually. Patients co-infected with HIV will often deteriorate quickly and die earlier. There are 3 different forms of leishmaniasis: cutaneous, visceral and mucocutaneous.

Cutaneous Leishmaniasis is the most common form and causes many skin ulcers and nodules on the exposed body parts such as the face, arms and legs. They occurred 2 to 8 weeks after being bitten by the infected sand fly. Without treatment, the ulcers usually heal in 3 to 12 months but leaving a scar. Peak transmission period occurs during and after rainy season. Each year about 1.5 million new cases were reported, of which 90% occur in West Asia (Afghanistan, Iran, Saudi Arabia, Syria) and South America (Brazil, Peru).

Visceral Leishmaniasis (also known as Kala azar) affects internal organs of the body including: the spleen, bone marrow, liver and lymph glands. The incubation period is between a few weeks to several months after being infected. Symptoms include: prolonged fever, weight loss, abdominal discomfort, enlarged abdomen and anemia. Without treatment, fatality is almost sure. About 50,000 new cases are reported each year and 90% of them occur in South Asia (Bangladesh, India, Nepal), Central Africa (Sudan), Central and South America (mainly in Brazil).

Mucocutaneous Leishmaniasis is characterized by progressive destruction of the mucous membranes of the nose, mouth, throat cavities and surrounding tissues, which can be severely disfiguring. This form of Leishmaniasis might develop years after the original skin sores healed. About 90% of reported cases occur in South America (Bolivia, Brazil and Peru).

How does it spread?

The protozoa is spread by the bite of infected female sand flies. The risk is highest from dusk to dawn when sand flies are the most active. They are less active during the day, but they will bite if disturbed. Rarely, it can spread through blood transfusion or from a pregnant woman to her fetus.

The disease is more common in rural than urban areas. High risk group includes people live or travel to endemic regions in particular, adventure travellers, missionaries, Peace Corps volunteers, soldiers, and people who study birds or doing research outdoors at night. There is no reported case in Australia or Oceania so far.

How can you prevent it?

No vaccines are available. The best way to prevent Leishmaniasis is by avoiding sand fly bites:

  • Stay in well-screened or air-conditioned areas. Use bed net with fine-mesh (at least 10 holes per cm) and has been treated with permethrin;

  • Avoid outdoor activities or visit forest areas, especially from dusk to dawn;

  • While outdoors, wear long-sleeved clothing and use insect repellents containing DEET (for children keep DEET concentration below 20%) on exposed body parties.

How is it treated?

Treatment is possible by pentamidine, sodium stibogluconate or meglumine antimonite. People should consult their doctor early even if their skin lesions have already healed by itself.



Last revision date: 10 October 2012