usually gastroenteritis is caused by bacteria viruses or parasites which can spread quickly through contaminated food or water. bacteria that cause gastroenteritis include escherichia coli salmonella campylobacter and shigella. these bacteria are usually found in food but can be spread person to person says david burkhart md a staff physician at the indiana university health center in bloomington. viruses that trigger gastroenteritis include adenoviruses rotaviruses calciviruses astroviruses and norovirus. certain viruses are found in specific places burkhart says. for instance norovirus often shows up on college campuses lingering on doorknobs and shared keyboards spreading the gastroenteritis among students. parasites and protozoans that commonly lead to gastroenteritis include giardia and cryptosporidium. the parasite giardia lives in the intestines of infected people or animals and often spreads when someone swallows polluted water. chemical toxins in seafood can also cause gastroenteritis so can exposure to heavy metals such as lead in drinking water. other causes of non-contagious gastroenteritis include food allergies caffeine or medications such as antibiotics steroids aspirin and laxatives.
what causes gastroenteritis?