Gastroenteritis, also known as stomach flu, is typically caused by a viral or bacterial infection. The most common causes of gastroenteritis include:
- Viruses: Viruses such as norovirus, rotavirus, and adenovirus are the most common cause of gastroenteritis, especially in children. These viruses can be easily spread through contaminated food, water, or surfaces.
- Bacteria: Certain types of bacteria, such as Salmonella, Escherichia coli (E. coli), and Campylobacter, can also cause gastroenteritis. These bacteria are usually transmitted through contaminated food or water.
- Parasites: Parasites such as Giardia lamblia and Cryptosporidium can cause gastroenteritis, especially in areas with poor sanitation or contaminated water sources.
- Food Poisoning: Eating contaminated food, such as raw or undercooked meat or poultry, can also cause gastroenteritis.
- Toxins: Certain toxins, such as those produced by Staphylococcus aureus or Bacillus cereus bacteria, can cause gastroenteritis.
There are also other unusual ways to get gastroenteritis:
- Heavy metals (arsenic, cadmium, lead, or mercury) in drinking water
- Eating a lot of acidic foods, like citrus fruit and tomatoes
- Toxins that might be found in certain seafood
- Medications such as antibiotics, antacids, laxatives, and chemotherapy drugs
Risk factors
Gastroenteritis occurs all over the world and can affect people of all ages. People who may be more susceptible to gastroenteritis include:
- Young children. Children in child care centers or elementary schools may be especially vulnerable because it takes time for a child’s immune system to mature.
- Older adults. Adult immune systems tend to become less efficient later in life. Older adults in nursing homes are vulnerable because their immune systems weaken. They also live in close contact with others who may pass along germs.
- Schoolchildren or dormitory residents. Anywhere that groups of people come together in close quarters can be an environment for an intestinal infection to get passed.
- Anyone with a weakened immune system. If your resistance to infection is low — for instance, if your immune system is compromised by HIV/AIDS, chemotherapy or another medical condition — you may be especially at risk.
Overall, gastroenteritis is typically caused by ingesting something that is contaminated with a virus, bacteria, parasite, or toxin, which can then infect the lining of the stomach and intestines, leading to symptoms such as diarrhea, vomiting, and abdominal pain.