bieneusi

Enterocytozoon bieneusi, commonly referred to as bieneusi, is a microsporidian parasite that infects the intestinal tract of humans and a wide range of animals, causing enteric microsporidiosis. It is one of the most frequently detected microsporidian species in humans and is a recognized cause of chronic diarrhea in immunocompromised individuals. Transmission occurs via the fecal-oral route, with infectious spores shed in feces that can persist in the environment, enabling ingestion through contaminated water or food.

In immunocompromised people, particularly those with advanced HIV infection or other causes of T-cell suppression, bieneusi infection presents with chronic watery diarrhea, abdominal pain, weight loss, and malabsorption. In otherwise healthy individuals, infection is often asymptomatic or induces mild gastrointestinal symptoms.

Diagnosis relies on detecting microsporidian spores in stool or intestinal tissue, using stains such as modified trichrome or calcofluor white, complemented by molecular methods like PCR targeting ribosomal RNA genes. Duodenal or jejunal biopsy can reveal intracellular spores within enterocytes.

Treatment is challenging; fumagillin is the primary antiparasitic agent used in many settings, though its availability and safety profile limit use in some regions. Albendazole is typically ineffective against E. bieneusi, and nitazoxanide has shown variable efficacy. In addition to antiparasitic therapy, improving immune function through antiretroviral therapy in HIV or reducing immunosuppression can improve outcomes.

Prevention emphasizes reducing fecal-oral transmission via safe water, proper sanitation, hand hygiene, and safe food handling.