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Key Features

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  • • A contagious disease largely limited to tropical regions that is caused by Treponema pallidum subspecies pertenue

    • Acquired by direct nonsexual contact, usually in childhood, although it may occur at any age

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Clinical Findings

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  • • Characterized by granulomatous lesions of the skin, mucous membranes, and bone

    • The “mother yaw,” a painless papule that later ulcerates, appears 3–4 weeks after exposure

    • Regional lymphadenopathy is usually present

    • Secondary lesions that are raised papillomas and papules

    • – Appear 6–12 weeks later

      – Weep highly infectious material

      – Last for several months or years

    • Painful ulcerated lesions on the soles are called “crab yaws” because of the resulting gait

    • Late gummatous lesions may occur, with associated tissue destruction involving large areas of skin and subcutaneous tissues

    • Late effects of yaws may be confused with similar changes occurring in leprosy and include

    • – Bone change

      – Shortening of digits

      – Contractures

    • Central nervous system, cardiac, or other visceral involvement is rare

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Diagnosis

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  • • Organisms can be demonstrated in infectious lesions with darkfield microscopy or immunofluorescence but cannot be cultured in artificial media

    • Serologic tests for syphilis are positive

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Treatment

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  • • If untreated, may lead to chronic disability and disfigurement

    • Penicillin, 2.4 million units of benzathine penicillin G intramuscularly is generally curative in any stage of the non–sexually transmitted treponematoses

    • In cases of penicillin hypersensitivity, tetracycline, 500 mg orally four times a day for 10–14 days, is the recommended alternative

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Content adapted from CURRENT Medical Diagnosis & Treatment 2014.

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Key Features

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  • • Zoonotic viral infection transmitted by the bite of the Aedes mosquito

    • Found in South America and sub-Saharan Africa (not Asia)

    • Incubation period is typically 3–6 days

    • Adults and children equally susceptible

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Clinical Findings

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  • • Mild form (85%)

    • – Fevers

      – Malaise

      – Retro-orbital pain

      – Nausea

      – Photophobia

      – Bradycardia

    • Severe form (15%)

    • – Begins with the same symptoms as the mild form of the disease

      – Then, after initial remission of symptoms, a toxic phase ensues with fever, bradycardia, hypotension, jaundice, delirium, hemorrhage

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Diagnosis

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  • • Leukopenia often but not always present

    • Abnormal liver function tests, including prolonged PT

    • Renal insufficiency with proteinuria is present, often in large quantities

    • Serologic diagnosis with rapid enzyme immunoassay

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Treatment

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  • • Supportive measures, including analgesia and hydration

    • No specific antiviral therapy

    • Prevention: a highly effective and safe vaccine is available and should be used when living or traveling to endemic areas

    • Prevention: mosquito control measures

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Content adapted from CURRENT Medical Diagnosis & Treatment 2014.

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