Parasites live in other host organisms and depend on them for survival. Parasites that can affect humans include ticks, lice, and hookworms. Symptoms of a parasite infection in humans can vary widely.

Jenna Demmer is a writer and editor that specializes in health. She has covered many topics including infectious diseases, women's health, mental health, sleep, and more. She has written for more than ...

Diarrhea and stomach pain can happen if you have a heavy intestinal worm infection, like tapeworm. You can check your poop ...

Intestinal worms are common parasites that live in the digestive system and can affect people of all ages. While many infections are mild and go unnoticed, some worms can cause discomfort, nutritional ...

Beth Skwarecki is Lifehacker’s Senior Health Editor, and holds certifications as a personal trainer and weightlifting coach. She has been writing about health for over 10 years. Ready to read ...