Primary infections with microsporidia may originate in which part of the body?

Microsporidia are a group of spore-forming unicellular parasites that are known to primarily infect the gastrointestinal tract, particularly in immunocompromised individuals. The gastrointestinal tract serves as a common entry point for these pathogens and is where they can establish infections, leading to significant gastrointestinal symptoms such as diarrhea, abdominal pain, and weight loss.

The life cycle of microsporidia typically involves the ingestion of spores from contaminated water or food, after which they invade the intestinal epithelial cells. This invasion can lead to various digestive complications, making the gastrointestinal tract the primary site of infection in the body.

While microsporidia can also be found in other body systems, including the lungs and nervous system, these locations are not considered primary sites of infection. Instead, the gastrointestinal tract is where the initial infection usually occurs. Therefore, the correct answer highlights the main route through which primary infections by microsporidia manifest in affected individuals.