Stomach viruses, also known as viral gastroenteritis or stomach flu, can be caused by a variety of viruses, most commonly rotavirus and norovirus, according to Healthline. Stomach flu is highly contagious and impacts people throughout the world. It spreads through contact with contaminated people, food and water. People in close quarters are especially susceptible, including those in nursing homes, cruise ships and schools. Symptoms include vomiting, diarrhea, fever, body aches and loss of appetite.
Bacteria such as E. coli and salmonella are common causes of viral gastroenteritis, according to WebMD. Salmonella is spread through undercooked foods such as eggs, poultry and poultry juices. Live poultry and reptiles can also spread the bacteria. Shigella is a bacteria that is spread through contaminated drinking water and is often found in day care centers. Parasites are known causes of stomach virus, including giardia and cryptosporidium. Exposure occurs through drinking or swimming in contaminated water.
Other less common causes of gastroenteritis include heavy metals found in drinking water, including mercury, lead, arsenic and cadmium, states WebMD. Toxins in certain seafood, and eating an excess of foods high in acidity such as tomatoes and citrus fruits, can cause the condition. Additionally, antibiotics, medications, antacids, laxatives and other medications can induce gastroenteritis.