Infectious diseases are a major source of sickness in infants and children, and most of these illnesses are caused by viruses. Although respiratory viruses get most of our attention, a viral infection of the gastrointestinal (digestive) tract is the major cause of diarrhea in children. Approximately 3.5 million cases of infectious diarrhea occur each year, and in children ages six months to three years, most are caused by the rotavirus.

The impact of this viral infection is significant, with about 125 deaths in the United States each year. Over 500,000 children visited a physician and 70,000 of these were hospitalized for dehydration annually after catching the rotaviral "bug." Rotavirus infections in young children usually produce fever and vomiting, followed by watery diarrhea. Symptoms usually last about five to seven days. The incubation period for rotavirus ranges from one to three days.

It is nearly impossible for a child attending daycare or preschool to avoid becoming infected with this microorganism. Since the rotavirus is excreted one to two days before the vomiting and diarrhea begins, it takes only twenty minutes for a child without symptoms to infect half the children in the daycare. Furthermore, the virus is so strong that a stool specimen containing the rotavirus can be diluted one billion times and still be infectious. In a recent study, researchers checked the floors, toys, and diaper changing areas of fifty clean day care centers. They found the virus on the surface of 56 percent of toilet handles, 44 percent of toy balls, 36 percent of diaper-changing areas, and 16 percent of drinking fountains! The virus can survive on plastic, glass, and steel surfaces for more than ten days. Since young children touch everything and are always putting their fingers in their mouths, protecting a young child from this virus is nearly impossible. The most effective way to reduce the spread of rotavirus from one child to another is through proper infection control. Good hand washing by everyone is perhaps the most effective prevention. Children should wash their hands after using the bathroom and especially before eating. Caretakers should wash their hands after each diaper change, and the changing area should be disinfected each time it is used.

The illness usually begins with an occasional bout of loose runny stools, and quickly progresses to frequent, watery bowel movements. Abdominal cramping, fever, and chills are also associated with this disease. The diagnosis can be confirmed in a laboratory by performing a rapid test for the rotavirus on a stool sample. The illness usually last five to seven days.

The possibility of dehydration (a medical emergency) increases when vomiting accompanies the diarrhea. A child with a rotavirus infection is not likely to develop dehydration as long as they can still drink. The signs of this medical emergency include:

• absence of saliva in the mouth

• sunken eyes

• markedly sunken fontanelle ("soft spot") in an infant

• no wet diapers or signs of urination for several hours

• loss of normal skin elasticity

• children usually become lethargic and drowsy whenever dehydration becomes a problem.

• tearless crying.

While the vast majority of children with rotavirus diarrhea make an uneventful recovery, the fact that some children become very sick with the disease has prompted health authorities to work on a vaccine. infants in the United States. This vaccine is now available and infants should routinely receive a 3-dose series of rotavirus vaccine orally at 2, 4, and 6 months of ag. For the time being, rotavirus control continues to rely on good hand-washing and disinfection of contaminated surfaces, and the isolation of symptomatic children.