Human Pythiosis

To the Editor: Over the past 2 decades, human pythiosis has emerged as an important parafungal disease; Thailand reports the most cases (1,2). Given the rarity of this infection in humans and the limited attention of researchers to the disease, our understanding of its pathogenesis and other important traits, including its management, await investigation. We report 2 distinct cases. The first patient was a 63-year-old woman with hemoglobin AEBart's disease, a complex thalassemia/ hemoglobinopathy syndrome, which required frequent blood transfusions. Two months before admission, after a major flood and exposure to standing water for weeks, an abnormal sensation developed in her right foot, which progressed to pain and intermittent claudication. Subsequent inability to walk prompted her to seek medical assistance. At admission, she was febrile with absence of pulses on the right lower extremity and a diminished pulse on the left. She had a peripheral blood eosinophilia of 10%. Emergency femoral angiography indicated complete obstruction of the right common iliac and left internal iliac arteries (Figure) with collateral supplies via lumbar arteries. Surgical intervention demonstrated a white clot from aortic bifurcation down to the right common iliac artery and the superficial and deep femoral arteries, surrounded by necrotic tissue and enlarged inguinal nodes. Right femoral embolectomy and aorto-femoral bypass were performed. A 10% KOH preparation of the clot and dissected nodes showed branching septate hyphae. Cultures of these specimens grew Pythium insidiosum. Itraconazole solution, terbinafine, and therapeutic vaccines (3) were administered. Extended-spectrum antimicrobial agents were also given during her hospital stay to combat nosocomial infections. Progressive wound necrosis and gangrene of the limbs dictated multiple debridements and subsequent limb amputations and hip disarticulation. Her clinical course worsened, and she died 2 months after admission. The second patient was a 15-year-old boy with β-thalassemia/hemoglo-bin E disease, 10 years after splenec-tomy. The patient received frequent blood transfusions and monthly intravenous deferoxamine for secondary hemochromatosis. Six days before admission to our hospital, necrotizing cellulitis of both legs, unresponsive to intravenous antimicrobial agents, was diagnosed at a local hospital. The patient reported frequent swimming in standing water in rice fields. He was febrile with a leukocyte count of 26,000/mm 3 and was given broad-spectrum intravenous antimicrobial agents. Severity of the lesions demanded surgical debridement (online Appendix Figure, available from showed necrosis of skin and subcuta-neous tissue but intact fasciae and muscles. Tissue pathology and fungal staining did not demonstrate the etio-logic agent. Surgical tissue …