Microsporidiosis is an infection caused by microscopic parasites known as microsporidia. These organisms can infect various tissues in the body, leading to symptoms such as diarrhea, weight loss, and abdominal pain. It is most commonly seen in individuals with weakened immune systems, such as those with HIV/AIDS or undergoing chemotherapy. Transmission of microsporidia typically occurs through contaminated water or food. The infection can be diagnosed through laboratory tests that identify the presence of the parasites in stool samples or tissue biopsies. Treatment often involves medications that target the parasites, although managing symptoms and supporting the immune system is also crucial.