By Drs. Sally Robinson and Keith Bly

Two of the most common types of parasitic infections that occur during the summer months are giardiasis and pinworms.

Giardia lamblia is a common microscopic parasite that attaches itself to the lining of the small intestines. It interferes with the body's ability to absorb fats and carbohydrates from digested food.

Kiddy pools are often a source of giardia, which is normally associated with food-borne outbreaks or fresh water, such as springs or creeks. Even kiddy pools that are treated and maintained with chemicals may be a source of this parasite, because chorine degrades in sunlight, and it degrades even more quickly in shallow water.

Symptoms of giardiasis include diarrhea, cramps, an extreme amount of intestinal gas that often causes an enlarged belly, loss of appetite, nausea and vomiting, a low-grade fever, and stools that are green and bubbly in appearance. Symptoms can last for five to seven days. If they last longer, they may cause weight loss and the child will begin to show signs of poor nutrition.

Giardiasis is contagious and can pass from stool into water, which can then pass to other humans, or it can be transmitted through uncooked food that has been rinsed in contaminated water. Giardiasis takes from one to three weeks to incubate after exposure. Treatment usually consists of five to seven days of anti-parasitic medication, and a child will normally recover within a week. If it goes untreated, giardiasis can last up to six weeks or longer.

Pinworms are the most common parasite that infects children. They are tiny parasitic worms that cause an intestinal infection. Pinworms do not cause any harm other than itching, but they are highly contagious.

A person with a pinworm infection may not realize it, because the only symptom is itching around the rectum. Pinworms may appear in a child's diaper, underwear, bedding, or in the toilet after your child uses the restroom.

Pinworm infections can be spread when someone who is infected scratches the itchy area and the eggs are transferred from their fingers to any object that they touch. Pinworm eggs can live on these objects for up to three weeks and can be transferred to anyone who touches them. Pinworms do not come from animals.

If your child's doctor finds that he or she has a pinworm infection, the doctor may give your entire family a dose of anti-worm medication. Several weeks later, the doctor may give another dose to everyone. Bed linens and pajamas should be washed in hot water daily until the infection has cleared, to get rid of any eggs.

During and after treatment, remember to:

· Remind your child to wash his or her hands thoroughly after using the toilet, playing outside and before eating. Remember to wash your hands as well.

· Bathe your child every day and make sure that he or she wears clean underwear and pajamas daily.

· Keep your child's fingernails short and clean.

• Tell your child not to scratch around his or her bottom.
Dr. Sally Robinson is a pediatrician in the division of children's special services at the University of Texas Medical Branch at Galveston. She teaches medical students about caring for children with chronic medical conditions. Dr. Keith Bly is a hospitalist and assistant professor of pediatrics at UTMB. This column is not intended to replace the advice of a physician.
The Your Health column is written by health and medical experts at the University of Texas Medical Branch at Galveston. The column focuses on topical health issues that we believe are of interest to your readers. It is e-mailed every Tuesday. If you have any questions about the column, or would like to suggest topics, please contact John Koloen, media relations specialist, at (409) 772-8790 or email jskoloen@utmb.edu.