But it may also occur from viral or bacterial infections. Average age of affected foals in one study was 70-days. Of foals with diarrhea, 77-90 percent were caused by rotavirus . Foals younger than 1 month are more severely affected with profuse, watery diarrhea. Rotavirus is extremely contagious since the virus is shed in the feces.
Foals become depressed, lose their appetites and normally have a fever.
Diarrhea follows in 12-24 hours and lasts for two to three days, but may linger for nine days. The feces may be normal to watery-yellow or gray. Foals younger than 2 days old usually have very watery diarrhea. They may become dehydrated, have an electrolyte imbalance and die from hypovolemic shock. If they become dehydrated, they need intravenous fluid therapy.