Vomiting is the first symptom in 80-90% of cases, followed within 24 hours by low-grade fever and profuse watery diarrhea. Diarrhea usually lasts 4 to 8 days but may last longer in young infants or patients with other health problems.

Replacement of fluids and electrolytes (the salts that are in our body fluids) is critical, or dehydration ensues. In most cases, replacing fluids by mouth suffices. One must use "oral rehydration fluid," such as Pedialyte(r), since this contains the proper concentrations of water, sugar, and electrolytes. Using other fluids, such as juices, carbonated beverages, or plain water, can aggravate the problem and actually make your child worse. It is still important to "feed" your child during these illnesses, since poor nutrition can allow the illness to last longer, and for your child to be sicker for a longer period of time.

The best way to ensure proper replacement of fluids lost through diarrhea, and to maintain proper nutrition, is to work with your health care provider. Very few children require hospitalization if the illness is handled appropriately at home.

Medications to control diarrhea are ineffective, and can be dangerous.

Repeat infections can occur, although they tend to be less severe. Prevention of rotavirus is mainly by good hygiene (washing of hands and not sharing feeding or bathing items) and prevention of fecal-oral contamination.

Dr. Larrabee is Associate Director of Family and Community Medicine at the Walter L. Aument Family Health Center, 317 S. Chestnut St., Quarryville.