Clinical Syndromes Associated with Microsporidiosis

This chapter describes the clinical and pathogenic features of the human infection with microsporidia. It focuses on gastrointestinal infection and nonocular manifestations of infection and provides a brief overview of epidemiology, immunology and laboratory diagnosis as it directly relates to human infections. Most microsporidian infections are transmitted by oral ingestion of spores, with the site of initial infection being the gastrointestinal tract. Ocular infections with ulcer or deep cornea stroma infection associated with eye pain have also been reported to be due to microsporidian infections in immunocompetent patients. Respiratory tract and sinus involvement has been reported in microsporidiosis due to the Encephalitozoonidae. Encephalitozoon sp. was reported as a cause of nodular skin lesions. Light microscopy is the standard technique for identification of microsporidia. Treatment of microsporidiosis, fumagillin and albendazole have demonstrated the most consistent activity and have been demonstrated to have clinical efficacy in human infections with various Microsporidia.