The two most important species are Enterocytozoon bieneusi and Encephalitozoon intestinalis. The most common manifestation of intestinal microsporidiosis in HIV-positive patients is profuse, watery, non-bloody diarrhoea, sometimes accompanied by abdominal pain and cramping, nausea, vomiting and weight loss. Species of microsporidia have been linked with disseminated disease: cholangitis, keratoconjunctivitis, hepatitis, peritonitis and infections of the lungs, muscles and brain. However, presence of microsporidia does not always correlate with symptomatic disease.

Treatment Albendazole is the treatment of choice for microsporidial disease.