Leishmaniasis

Leishmaniasis is caused by parasites that are transmitted by the bite of infected female phlebotomine sandflies.

There are three main forms of leishmaniases: – visceral (also known as kala-azar and the most serious form of the disease), cutaneous (the most common), and mucocutaneous. Depending on the type of leishmaniasis, symptoms can range from fever, weight loss, lesions and life-long scaring, and partial or total destruction of mucous membranes of the nose, mouth, and throat. Kala-azar is fatal if left untreated in over 95% of cases.

Leishmaniasis is linked to environmental changes such as deforestation, building of dams, irrigation schemes, and urbanization. It affects some of the poorest people on earth, and is associated with malnutrition, population displacement, poor housing, a weak immune system, and lack of financial resources. Leishmaniasis is a treatable and curable disease.

The Western Pacific Region is not endemic for Leishmaniasis although China is considered endemic with very low endemicity. No data has been reported in the last two years. Only 5 cases of cutaneous leishmaniasis were reported in 2015.

Cutaneous leishmaniasis usually produces ulcers on the exposed parts of the body, such as the face, arms and legs. There may be many lesions – sometimes up to 200 – which can cause serious disability. When the ulcers heal, they invariably leave permanent scars, which can lead to stigmatization, especially for women and girls.

Visceral leishmaniasis is characterized by irregular bouts of fever, substantial weight loss, swelling of the spleen and liver and serious anaemia. If the disease is not treated, the fatality rate can be as high as 100% within 2 years.

Mucocutaneous leishmaniasis produces lesions that can partially or totally destroy the mucous membranes of the nose, mouth and throat cavities and surrounding tissues. This disabling form can also lead to social exclusion.

Post-kala-azar dermal leishmaniasis (PKDL), a complication of visceral leishmaniasis, is mainly seen in east Africa and south-east Asia. It is characterized by a discoloured (hypopigmented) flat skin (macular) rash, combined with some slightly elevated (maculopapular) or elevated (nodular) rash, usually in patients who have recovered from visceral leishmaniasis. PKDL usually appears 6 months to 1 or more years after apparent cure of visceral leishmaniasis. It may occur earlier or even concurrently with visceral leishmaniasis, especially in Sudan. PKDL heals spontaneously in most cases in Africa but rarely in patients in India.

Antileishmanial treatment depends on the causative species and the condition of the patient (e.g. pregnancy, immunosuppression).

Regardless of the causative Leishmania species, antileishmanial treatment cannot provide a sterile cure, and the parasite remains in the human body and can cause a relapse when there is immunosuppression.

Treatment is complex and should be administered by highly experienced health personnel. Most antileishmanial medicines are injectable.