Stomach flu symptoms to watch for as outbreak spreads across US: CDC
Stomach bugs are in bloom in the US. Also known as the stomach flu (though unrelated to influenza), the highly contagious gastrointestinal illness is typically caused by norovirus infection, prompting days of vomiting, diarrhea and fever in children and adults — which could even lead to death if not properly treated.
Even a small colony of norovirus particles can wreak havoc in a short period of time, which explains the rapid-fire outbreaks. Just 100 particles are enough to make one sick, though infected people may shed billions of them.