Illustration of a Gastrointestinal Infection

Gastrointestinal Infections Overview

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Abdominal infections are infections caused by bacteria, viruses, or pathogens that affect your abdominal area. Also sometimes called gastrointestinal infections, the most common symptom is diarrhea along with vomiting and nausea, cramps, bloating, lack of appetite and fever. The vast majority of these infections go away on their own in a few days, but those that linger can be treated with antibiotics or antiparasitic medications, depending on the exact cause. If needed, your doctor can identify the organism causing your symptoms with a lab test.

What Is It

Abdominal infections refer to a wide range of infections from pathogens such as bacteria, viruses, and parasites that can affect different parts of your abdomen. The category includes gastrointestinal infections, which occur in your digestive tract.

The severity of the infection depends on what part of the body is involved and on the particular organ. Infections that spread beyond the original site are referred to as "complicated" infections and could lead to sepsis (when your immune-system response starts to damage internal organs) or even septic shock, which is life-threatening.


Gastrointestinal infections can be categorized in several different ways. One way is to sort them by their cause which is usually either a bacteria, virus, or parasite. Abdominal infections are also differentiated by where you initially get infected. Hospital-acquired infections (nosocomial infections) come from healthcare settings such as hospitals and are typically more serious as they can involve difficult-to-treat, antibiotic-resistant bacteria. Community-acquired infections are spread outside of healthcare facilities.


If you've ever had food poisoning, then you are probably familiar with the main symptoms of gastrointestinal infections. The most common is diarrhea, often accompanied by nausea and vomiting, cramps, bloating, fever, and lack of appetite. In most cases the symptoms only last a few days. If they persist beyond two weeks, they're considered chronic and it's time to get medical help.

Severe infections might also show up as blood in your vomit or stool, headaches, weakness, chest pain, irregular heartbeat, confusion, or weight loss. Dehydration, which can be life-threatening, is always a potential complication when you have diarrhea and vomiting. Symptoms can develop anywhere from four hours to four days to four weeks after infection, depending on the cause.


Viruses are the most common cause of gastrointestinal infections. In adults, the most frequent viral culprit is norovirus (widespread on cruise ships) and in children, it's rotavirus. Adenoviruses frequently cause abdominal infections in children. Hepatitis A, spread through contaminated food or water, is another culprit.

The most common bacteria causing gastroenteritis is Salmonella, which hides in contaminated meat products, chicken, produce, and eggs, and can cause typhoid fever. Some people have become infected from pet turtles and iguanas. Other common bacterial sources of gastrointestinal infection are:

  • Staphylococcus aureus, found on your skin and in foods like meat, poultry, eggs, dairy products, and eggs.
  • Shigella, found in feces and contaminated water.
  • Bacillus cereus, linked with fried rice.
  • Campylobacter, in dairy products, produce, meat, and poultry.
  • Escherichia coli (E. Coli), in water contaminated with feces as well as produce, uncooked beef, and unpasteurized milk.
  • Clostridium difficile is often contracted in healthcare settings, which means it often affects people who are already medically vulnerable.
  • Listeria, from produce, deli meats and undercooked meats.
  • Helicobacter pylori (H. Pylori), from dirty water or eating utensils, as well as food or another person's body fluids including saliva. This type of infection is linked with ulcers and stomach cancer.
  • Parasites, which can cause abdominal infections. These include Giardia lamblia (found in water), intestinal worms, such as hookworm and tapeworm, Cryptosporidium, and Toxoplasma gondii.

In communities, infections most often spread from person to person or through contaminated food or water. In healthcare settings, they can also spread via contaminated equipment, such as catheters or surgical instruments.


Many abdominal or gastrointestinal infections don't need to be diagnosed, as they typically go away on their own in a few days. If you do need to see a doctor, he or she will likely start by asking questions and giving you a physical examination in the office. Laboratory tests can often reveal exactly what is causing the infection. Nowadays, doctors often turn to molecular tests which look for traces of an organism and can return results quickly, sometimes in just a few hours.

Imaging tests such as CT scans can deliver more information on the condition of the internal organs, while a breath test can detect H. pylori.


The many gastrointestinal infections that go away on their own typically don't need to be treated, just as they don't require a diagnosis. That doesn't mean there's nothing you can do. In fact, it's important to drink lots of water and other fluids to replace those that are lost through diarrhea and vomiting. Broth or soup with sodium as well as 100% fruit juice with potassium are good options. When you're ready to eat, focus on bland foods like the BRAT (banana, rice, apple, toast) diet rather than high-fat, high-fiber, and dairy products, which can backfire and produce more symptoms.

The most common treatment for bacterial infections is antibiotics. Your doctor will choose an antibiotic based on the specific infection. Hospital-acquired infections, such as MRSA (methicillin-resistant Staphylococcus aureus) can be much more difficult to treat because they no longer respond to many commonly used antibiotics.

Antibiotics can also treat some parasitic infections, as can antiparasitic medications, but there really are no treatments for viral infections. You just have to keep an eye on them and make sure you don't get dehydrated. If you do get dehydrated, you may need to go to the hospital to be given intravenous (IV) fluids.

If an abscess develops, you may need a drain to get rid of contaminated fluid. Occasionally, surgery is needed, for instance to remove an infected and inflamed appendix. You may also need surgery to remove an ulcer.


The best way to prevent gastrointestinal infections is to practice good hygiene, namely by washing your hands well after using the bathroom and before eating or preparing food, as well as many times in between. If soap and water aren't available, use an alcohol-based sanitizer with at least 60% alcohol. Keep bathroom and kitchen surfaces clean.

Proper food handling and preparation can also prevent abdominal infections:

  • Always wash raw fruits and vegetables before eating.
  • Make sure all meat is cooked thoroughly (and don't eat undercooked meat when you're dining out).
  • Refrigerate leftovers right after the meal.
  • Clean surfaces frequently, especially after they've been in contact with raw meat or eggs.
  • When traveling, don't eat anything raw (unless it's a banana) and only drink water that's been boiled or comes from a bottle, even when brushing your teeth.

Healthcare facilities are adopting measures to reduce the incidence of nosocomial infections. You can prevent rotavirus illnesses in children by having them vaccinated. There is also a vaccine for Hepatitis A.

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