Leishmaniasis is a parasitic infection caused by different species of Leishmania protozoa. It is transmitted through the bite of infected female sandflies belonging to the Phlebotomus, Lutzomyia, and Psychodopygus species. These nocturnal insects bite from dusk to dawn and are often found in forests, stone and mud walls cracks, and animal burrows. They are very tiny silent flyers – they do not hum – and their bite might go unnoticed. Leishmaniasis is clinically divided into three major categories – cutaneous, mucocutaneous, and visceral – and is a Neglected Tropical Disease (NTD)*.
* Neglected Tropical Diseases are chronic infections that are typically endemic in low income countries. They prevent affected adults and children from going to school, working, or fully participating in community life, contributing to stigma and the cycle of poverty.
Adventure travellers, bird watchers, missionaries, army personnel, construction workers, and researchers on night time assignments are at higher risk of being exposed to sandflies.
Cutaneous Leishmaniasis is the most common form of the infection and is found in two geographic areas:
Symptoms of Cutaneous Leishmaniasis: Initial symptoms include skin lesions, which develop after several weeks or months after being infected, and swollen glands. The lesions – closed or open sores – can change overtime in size and appearance. They are usually painless, but can become painful if infected with bacteria. The lesions can take a long time to heal and usually leave scarring. Infections with some strains of New World cutaneous leishmaniasis may develop into Mucocutaneous Leishmaniasis years after the initial skin lesions seem to have healed completely. The infection spreads to the nose, mouth, and throat causing sores and bleeding. This complication can occur when the initial Cutaneous Leishmaniasis infection has not been treated.
Visceral Leishmaniasis, also know as kala-azar, is caused by some Leishmania species that invade the liver, spleen, bone marrow, and skin. This form of Leishmaniasis is very rare in travellers but it affects local populations in remote areas of India, Nepal, Bangladesh, Sudan, South Sudan, Ethiopia, and Brazil.
Symptoms of Visceral Leishmaniasis: Usually symptoms appear weeks or months after being infected and include fever, weight loss, and enlarged liver. Advanced untreated visceral leishmaniasis can be fatal, particularly if other pre-existing conditions such as tuberculosis, pneumonia, and dysentry are present.
There is no preventive vaccination or medication against Leishmaniasis. Treatment options depend on identifying the infective leishmania species and the extent of the infection, but includes antifungal drugs and antibiotics.
Leishmania protozoa images, life cycle, and distribution maps:
Information last updated: September 28, 2020