When kids have a viral gastroenteritis (usually vomiting/diarrhea), the vomiting usually lasts no more than a day or two but the diarrhea can last for up to a week. And if that type of illness is going around your daughter's school, she might have even caught it again. Hand washing is the best way to prevent it. I recommend one of those waterless, alcohol-based, instant hand sanitizers--especially before eating. Most of those germs come in through the mouth from the hands.

Although it's not uncommon to get the same virus twice, there are many viruses that can cause those symptoms and only a few ways the body has for getting rid of them. Vomiting and diarrhea are the main two ways to eject GI viruses.

It's normal for a child's appetite to be down during an illness like that and there is no need to force otherwise healthy kids to eat. One family of viruses that can cause those symptoms, the enteroviruses, commonly knock out the appetite. That actually may be part of the body's way of fighting the germs off; decreased appetite might shunt some of the blood flow away from the intestines. It is important, though, for kids to drink a lot throughout the illness. Dehydration is the main risk from gastroenteritis. Try giving her clear liquids in small amounts (if the stomach gets full, it increases the chance of vomiting).