Case19 - Leishmania

Case19 - Leishmania - Case 19 Lydyard Peter Cole Michael...

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1. What is the causative agent, how does it enter the body and how does it spread a) within the body and b) from person to person? Causative agent Leishmania are protozoan parasites. They have an intracellular form called an amastigote (Figure 2) and an extracellular, flagellated form called a pro- mastigote (Figure 3). There is variety in the clinical diseases caused, geographical distribution, and animal reservoirs. The genus Leishmania is divided into groups, species, and complexes. Classification was classically determined by isoen- zyme typing ; molecular methods (using DNA) are now more common. Table 1 lists species and the diseases they cause. Case 19 Leishmania spp. A 72-year-old gentleman retired to the south of Spain but returned to the UK for the summer months. He began to develop fever, malaise, loss of appetite, and weight loss. He was admitted to hospital and had temperatures reaching 39 C. Both his liver and spleen were palpable. No lymph nodes could be felt. Blood tests showed a pancytopenia . Routine investigations for an infection were negative and he did not improve with broad- spectrum antibiotics. His condition deteriorated and the size of the liver and spleen increased (Figure 1). A bone marrow examination did not show any sign of hematological malignancy. No organisms were seen on staining. His history was explored again. Four months before his illness he had been on a camping break in Spain to a coastal area. He recalled seeing many thin dogs in the vicinity. Part of his bone marrow sample was sent to a reference laboratory for Leishmania polymerase chain reaction ( PCR ). This returned positive. He was successfully treated with a course of liposomal amphotericin B and over the ensuing 3 months his liver and spleen became impalpable and his blood tests returned to normal. His diagnosis was visceral leishmaniasis probably due to Leishmania infantum . Figure 1. A child with visceral leishmaniasis. As in the patient described in the case history the liver and spleen are enlarged, causing distension of the abdomen. Figure 2. A skin biopsy showing Leishmania amastigotes (arrowed). © Lydyard, Peter; Cole, Michael; Holton, John; Irving, Will; Porakishvili, Nino; Venkatesan, Pradhib; Ward, Kate, Jan 01, 201 Garland Science, Hoboken, ISBN: 9780203856871
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Entry and spread within the body People are infected after the bite of a sandfly laden with Leishmania pro- mastigotes. Under the skin the promastigotes are rapidly phagocytosed by macrophages. For cutaneous disease lesions are confined to the locality of the sandfly bite. For L. braziliensis and L. panamensis cutaneous spread can occur and later this can involve mucous membranes of the mouth or nose. L. donovani
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This note was uploaded on 09/14/2011 for the course PHARM mb taught by Professor Staff during the Spring '11 term at UCSD.

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Case19 - Leishmania - Case 19 Lydyard Peter Cole Michael...

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