Medically reviewed by Robert Burakoff, MDIntestinal worms often lead to gastrointestinal symptoms, like diarrhea, because ...

The threadworm infection cycle begins when immature larvae excreted in the host poop develop into larvae. The infective larvae then crawl off the poop and into the soil to search for a host to infect.

Globally, over 600 million people are infected with the skin-penetrating threadworm, Strongyloides stercoralis, mostly in tropical and subtropical regions with poor sanitation infrastructure.