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For further information, see CMDT Part 35-03: Leishmaniasis

Key Features

Essentials of Diagnosis

  • Sand fly bite in an endemic area

  • Irregular fever, progressive hepatosplenomegaly, pancytopenia, wasting

  • Amastigotes in macrophages in aspirates, touch preparations, or biopsies

  • Positive culture, serologic tests, polymerase chain reaction (PCR), or skin test

General Considerations

  • The disease is caused mainly by

    • L donovani in the Indian subcontinent and East Africa

    • L infantum in the Mediterranean, Middle East, China, parts of Asia, and Horn of Africa

    • L chagasi in South and Central America

  • Other species may occasionally cause visceral disease

  • In each locale, the disease has particular clinical and epidemiologic features

  • Infection is transmitted by bites of sand flies

  • Clinical syndromes generally dictated by infecting species, but some species cause more than one syndrome

  • The incubation period is usually 4–6 months (range: 10 days to 24 months)

Demographics

  • Over 90% of cases occur in 6 countries

    • India

    • Bangladesh

    • Nepal

    • Sudan

    • South Sudan

    • Brazil

  • The estimated annual incidence of disease has been decreasing; current estimate is 50,000–90,000

  • Progress against visceral disease has been greatest on the Indian subcontinent

Clinical Findings

Symptoms and Signs

  • Most infections are subclinical

  • A small number progress to full-blown disease

  • A local nonulcerating nodule at the site of the sand fly bite may precede systemic manifestations but usually is inapparent

  • Onset may be acute, within 2 weeks of infection, or insidious

  • Fever, chills, sweats, weakness, anorexia, weight loss, cough, and diarrhea

  • Spleen progressively becomes greatly enlarged, firm, and nontender

  • Liver is somewhat enlarged

  • Generalized lymphadenopathy may occur

  • Hyperpigmentation of skin can be seen, leading to the name kala azar ("black fever")

  • Skin lesions, petechiae, gingival bleeding, jaundice, edema, and ascites

  • As the disease progresses, severe wasting and malnutrition are seen

  • Viscerotropic leishmaniasis has been reported in small numbers of American military personnel in the Middle East, with mild systemic febrile illnesses after L tropica infections

  • Can present late in course of HIV infection

    • Fever, hepatosplenomegaly, pancytopenia

    • Gastrointestinal tract, respiratory tract, and skin may also be involved

Differential Diagnosis

  • Leukemia or lymphoma

  • Cirrhosis

  • Tuberculosis

  • Histoplasmosis

  • Infectious mononucleosis

  • Brucellosis

  • Malaria

  • Typhoid fever

  • Schistosomiasis

  • African trypanosomiasis

  • Tropical splenomegaly syndrome

Diagnosis

Laboratory Tests

  • Cultures with media available from the CDC will grow promastigotes within a few days to weeks

  • Molecular assays can also be diagnostic

  • Serologic tests

    • May facilitate diagnosis

    • None are sufficiently sensitive or specific to be used alone

  • Numerous antibody-based rapid diagnostic tests are available

    • Specificity is good

    • Sensitivity outside of India is limited

Diagnostic Procedures

  • Fine-needle aspiration of spleen for culture and tissue evaluation

    • Generally safe

    • Yields a diagnosis in over 95% of cases

  • Bone marrow aspiration

    • Less sensitive but safer

    • Diagnostic ...

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