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American cutaneous leishmaniasis

Secondary lesions occur on the skin as well as in mucous membranes
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The American cutaneous leishmeniasis is the same as oriental sore. But some of the strains tend to invade the mucous membranes of the mouth, nose, pharynx, and larynx either initially by direct extension or by metastasis. The metastasis is usually via lymphatic channels but occasionally may be the bloodstream.

Pathogenesis

The lesions are confined to the skin in cutaneous leishmaiasis and to the mucous membranes, cartilage, and skin in mucocutaneous leishmaniasis. A granulomatous response occurs, and a necrotic ulcer forms at the bite site. The lesions tend to become superinfected with bacteria. Secondary lesions occur on the skin as well as in mucous membranes. Nasal, oral, and pharyngeal lesions may be polypoid initially, and then erode to form ulcers that expand to destroy the soft tissue and cartilage about the face and larynx. Regional lymphadenopathy is common.

Epidemiology

Most of the cutaneous and mucocutaneous leishmaniasis of the new world exist in enzootic cycles of infection involving wild animals, especially forest rodents. Leishmaniamexicana occurs in south and Central America, especially in the Amazonbasin, with sloths, rodents, monkeys, and raccoons as reservoir hosts. 
The mucocutaneous leishmaniasis is seen from the Yucatan peninsula into Central and South America, especially in rain forests where workers are exposed to sand fly bites while invading the habitat of the forest rodents. There are many jungle reservoir hosts, and domesticated dogs serve as reservoirs as well. The vector is the Lutzomyia sand fly.

Clinical features

The types of lesions are more varied than those of oriental sore and include Chiclero ulcer, Uta, Espundia, and Disseminated Cutaneous Leishmaniasis.

Laboratory diagnosis

• Demonstration of the amastigotes in properly stained smears from touch preparations of ulcer biopsy specimen.
• Serological tests based on fluorescent antibody tests.
• Leishman skin test in some species.



Immunity

The humoral and cellular immune systems are involved
Treatment
The drug of choice is sodium stibogluconate.

Prevention

• Avoiding endemic areas especially during times when local vectors are most active.
• Prompt treatment of infected individuals.


American cutaneous leishmaniasis American cutaneous leishmaniasis Reviewed by gafacom on November 27, 2019 Rating: 5

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