Threadworms (pinworms) are small parasites that infect the intestines of humans. Threadworms cause itching around the anus and vagina. The itching is worst at night when the female worms lay their eggs. If you scratch, worms can stick under fingernails and be transferred to the mouth to cause new infection. Threadworms can cause loss of appetite, weight loss, sleepiness and severe irritability. All household members must be treated at the same time if anyone is infected. Practice good hygiene to avoid threadworm.
Attribution: Straight Talk Foundation