A gastrointestinal infection can be caused by bacteria, virus, or parasites. These infections are extremely common in people. In fact, according to the Center for Disease Control and Prevention (CDC), these infections and diarrheal disease account for 1 in every 9 child deaths in the world.

Common causes

Bacteria

• E. coli– This type of bacteria is most commonly found in the intestines of humans and animals. While most varieties of these bacteria are harmless, there are a few types that may harm the body. These few varieties secrete a toxin that can lead to agonizing symptoms like bloody diarrhea, vomiting, and abdominal cramping. In most cases, these bacteria are spread through contaminated food and water that have come in direct contact with animal waste. Sometimes, direct contact with an infected person can also cause an infection.
• Salmonella– The most common cause of this infection is the consumption of raw and undercooked meat, poultry and eggs.

Viral

• Norovirus- This virus is one of the leading causes of food-borne illnesses affecting people throughout the world. It spreads among people in close and confined spaces. Norovirus is most likely to spread through direct contact with contaminated food and water.
• Rotavirus- Many studies have shown that rotavirus is the leading cause of gastrointestinal infection in children worldwide. Children acquire the infection when they touch any infected item and then put their finger in their mouth. The rotavirus vaccination that is available helps in substantially bringing down the risk of developing this infection.

Parasite

• Giardia- Giardi is one of the primary causes of waterborne gastrointestinal infections. The infection caused by giardia in the small intestine is known as giardiasis. This parasite can quickly spread through contaminated water and sometimes through direct contact. Also, the parasite is not affected by chlorine so it is very commonly found in public swimming pools.
• Cryptosporidium– Cryptosporidium is a parasite that causes cryptosporidiosis. This parasite again causes waterborne infections as it is resistant to chlorine.

Risk factors
The following people are at higher risk of suffering from a gastrointestinal infection:

• Infants and little children are at an increased risk of these infections as they do not have a very strong immune system. On the other hand, elderly people are more prone to it because of a weakened immune system.
• People who have a weakened immune system because of illnesses like HIV/AIDS
• People who are constantly traveling to places where food or water may be contaminated
• People living in crowded areas

When to see a doctor?
A gastrointestinal infection, if left untreated, can lead to serious complications. Therefore, if you suspect any symptoms of the same, you should immediately seek medical help. Also, you need to consult your doctor in case of the following symptoms:

• Fever above 104°F
• Persistent vomiting for more than 48 hours
• Inability to keep the liquids down for 24 hours
• Blood in the vomit
• Dehydration, which causes a dry mouth, increased thirst, little or no urine, and extreme weakness
• Blood in the stool

The doctor would examine the cause of the symptoms and create a treatment plan accordingly. It is best to seek the counsel of a doctor in cases of gastrointestinal infections, especially in kids, rather than treating yourself on your own.