A group of infections caused by parasites transmitted to humans by sand?ies.
Visceral leishmaniasis (kala-azar) A systemic infection caused by Leishmania donovani which occurs in tropical and subtropical Africa, Asia, the Mediterranean littoral (and some islands), and in tropical South America. Onset is frequently insidious; incubation period is 2–6 months. Enlargement of spleen and liver may be gross; fever, anaemia, and generalised lymphadenopathy are usually present. Diagnosis is usually made from a bone-marrow specimen, splenic-aspirate, or liver-biopsy specimen; amastigotes (Leishman-Donovan bodies) of L. donovani can be visualised. Several serological tests are of value in diagnosis.
Untreated, the infection is fatal within two years, in approximately 70 per cent of patients. Treatment traditionally involved sodium stibogluconate, but other chemotherapeutic agents (including allupurinol, ketoconazole, and immunotherapy) are now in use, the most recently used being liposomal amphotericin B. Although immunointact persons usually respond satisfactorily, they are likely to relapse if they have HIV infection (see AIDS/HIV).
Cutaneous leishmaniasis This form is caused by infection with L. tropica, L. major,
L. aethiopica, and other species. The disease is widely distributed in the Mediterranean region, Middle East, Asia, Africa, Central and South America, and the former Soviet Union. It is characterised by localised cutaneous ulcers
– usually situated on exposed areas of the body. Diagnosis is by demonstration of the causative organism in a skin biopsy-specimen; the leishmanin skin test is of value. Most patients respond to sodium stibogluconate (see above); local heat therapy is also used. Paromomycin cream has been successfully applied locally.
Mucocutaneous leishmaniasis This form is caused by L. braziliensis and rarely L. mexicana. It is present in Central and South America, particularly the Amazon basin, and characterised by highly destructive, ulcerative, granulomatous lesions of the skin and mucous membranes, especially involving the mucocutaneous junctions of the mouth, nasopharynx, genitalia, and rectum. Infection is usually via a super?cial skin lesion at the site of a sand?y bite. However, spread is by haematogenous routes (usually after several years) to a mucocutaneous location. Diagnosis and treatment are the same as for cutaneous leishmaniasis.... leishmaniasis
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