According to the University of Maryland Medical Center, intestinal worms can live in human intestines without causing outward signs of their presence. Intestinal worm parasites found in humans are helminths, or many-celled worms, unlike other parasites that are single-celled. Adult helminths cannot reproduce inside the human body, so their eggs are transmitted from outside sources. Exposure to intestinal worms may occur any place an infected person has been. Your child can pick up the microscopic parasite eggs just by touching surfaces where the eggs are present, and they are easily transferred to his mouth on fingers or toys. (RES 1)
Itching
Pinworm eggs can be picked up nearly anywhere. Kidshealth.org explains that after your toddler ingests the eggs, it takes one to two months for the pinworms to mature in her intestines. At that time, the mature female pinworms migrate to lay their eggs in the area around your child's rectum. Toddlers rub or scratch the resulting itch, which moves the new eggs to their clothing or fingers and sets up a cycle of infection. You may detect the tiny, half-inch long worms in your toddler's stool.
Restless Sleep
The itching from pinworms at night can interfere with your toddler's sleep. Pinworms are often more active at night, according to Kidshealth.org. Contact your doctor if you suspect that your child is infected.
Vaginal Discharge
Little girls may develop vaginal itching or discharge from pinworms. When she scratches, your toddler may transfer eggs or pinworms to her vaginal area, and the resulting itch may cause additional irritation. Eggs or worms can also be transferred on her underwear or pajamas, or even towels and sheets.
Tummy Ache
Abdominal pain can be a sign of an ascaris, or roundworm, infection. Adult roundworms live in the intestines, and remain there until they are killed by medication. Ascaris infections are rare in the United States, reports the Centers for Disease Control.
Slow Growth
Roundworms steal nourishment from your toddler's digestive tract, and a roundworm infection may result in slow growth or slow weight gain. The Centers for Disease Control says that you might also notice a roundworm in your toddler's stool, and you should seek your doctor's advice.
