Types of Stomach Flu Viruses
There are four main types of stomach flu viruses: rotavirus, adenovirus, caliciviruses, and astrovirus. They all attack the cells lining the small intestine, which is why the symptoms of each virus are so similar. Of the types of stomach flu viruses, some are more likely to affect children, for example, than adults, and some cause more severe symptoms than the others.
There are a number of viruses that can cause stomach flu (the medical term is viral gastroenteritis). Each type of stomach flu virus causes stomach flu symptoms by damaging the cells in the lining of the small intestine. As a result, fluids leak from the cells into the intestine and produce watery diarrhea. There are four main types of stomach flu viruses:
Rotavirus is the leading cause of stomach flu among children 3 months to 15 months old, and is the most common cause of diarrhea in children under the age of 5 years. Rotavirus symptoms appear 1 to 2 days after exposure. Rotavirus typically causes vomiting and watery diarrhea for 3 to 8 days, along with fever and abdominal pain. This type of stomach flu virus can also infect adults who are in close contact with infected children, but the symptoms in adults are milder (see Adult Rotavirus). In the United States, rotavirus infections are most common from November to April.
Adenovirus occurs mainly in children under the age of 2 years. Of the 49 types of adenoviruses, one strain affects the gastrointestinal tract, causing vomiting and diarrhea. Symptoms typically appear 1 week after exposure. Adenovirus infections occur year-round.