Norovirus. With norovirus — the most common cause of viral gastroenteritis in adults — you're contagious when you begin to feel ill. Symptoms.
This condition, often called stomach flu, is usually harmless, except for Adults infected with rotavirus may not have symptoms, but can still.
The stomach flu or gastroenteritis is caused by bacteria, viruses, and parasites. Symptoms include vomiting, diarrhea, nausea, and abdominal.
Knowing how long stomach flu lasts in adults will help reassure you that your symptoms won't last forever. Here's how to feel better faster.