Paracoccidioides brasiliensis is the cause of paracoccidioidomycosis (South Americanblastomycosis), a disease limited to tropical and subtropical areas of Central and South America. The organism is a dimorphic fungus, the most noteworthy feature of which is the production of multiple blastoconidia from the same cell. Characteristic 5- to 40-μm cells covered with budding blastoconidia may be seen in tissue or in yeast-phase growth at 37°C. The disease manifests primarily as chronic mucocutaneous or cutaneous ulcers. The ulcers spread slowly and develop a granulomatous mulberry-like base. Regional lymph nodes, reticuloendothelial organs, and the lungs may also be involved.
Little is known of the pathogenesis of the disease, although the route of infection is believed to be inhalation. Progression in experimental animals is associated with depressed T lymphocyte-mediated immune responses. The disease has a striking predilection for men, despite skin test evidence that subclinical cases occur at the same rate in both sexes. This may be related to the experimental observation that estrogens but not androgens inhibit conversion of mold-phase conidia to the yeast phase. Treatment is with sulfonamides, amphotericin B, and, more recently, the azole compounds.
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