Gastroenteritis is a condition involving inflammation of the lining of the gut - in particular, of the stomach, and small and large intestines.1,2
Food poisoning is a major cause of gastroenteritis, resulting in a well-known set of unpleasant symptoms. In most people, gastroenteritis resolves without medical help, but the condition can lead to severe dehydration and other dangerous complications in some people.
Gastroenteritis is usually caused by viruses, bacteria or parasites; where the source of such infection is contaminated food, this is called food poisoning. Gastroenteritis may also be referred to as "gastric flu" or "stomach flu."1,2
Contents of this article:
Fast facts on gastroenteritis and food poisoning
Here are some key points about food poisoning and gastroenteritis. More detail and supporting information is in the body of this article.
- Most cases of gastroenteritis are caused by infection with bacteria, viruses, or parasites.
- Diarrhea, nausea, vomiting, and abdominal pain are typical symptoms of gastroenteritis.
- Different types of food poisoning produce different symptoms - for example, mucus and blood may be seen in bacterial diarrhea.
- Gastroenteritis is usually self-limiting, and tests are not usually necessary for a diagnosis.
- The greatest risk from food poisoning and gastroenteritis is dehydration, especially for vulnerable people such as the very young and very old.
- Treatment is focused on relieving symptoms, and self-care to prevent dehydration, such as ensuring adequate intake of fluid and replacement electrolytes.
- Drug treatments are available to reduce diarrhea and vomiting.
- Separating and chilling foods, cooking them properly and exercising good hygiene helps to prevent food poisoning.
Causes of food poisoning and gastroenteritis
The US Food and Drug Administration cites that, in spite of high standards in the US food supply, about 48 million cases of foodborne illnesses occur annually because of contaminated food. It estimates that 128,000 hospitalizations and 3,000 deaths result from food poisoning.3
The regulator has produced a complete list of microorganisms responsible for these illnesses, along with a description of the symptoms each of these infections typically produces.
Abdominal cramps can be a symptom of gastroenteritis.
In broad terms, there are three groups of infectious agents that cause gastroenteritis:1
The viruses that are most commonly implicated in gastroenteritis are:1
- Rotavirus - the most common cause of severe diarrhea in children
- Norovirus - more common in adults.
Less common viral causes are astrovirus, usually affecting children in winter, and adenoviruses, mostly affecting very young children. Also, gastroenteritis may occur in patients who have compromised immunity and become exposed to, for example, cytomegalovirus or enterovirus.
The bacteria that are most commonly implicated in gastroenteritis are:1
- Escherichia coli (especially serotype O157:H7)
- Clostridium difficile.
A study from the US Centers for Disease Control and Prevention's Interagency Food Safety Analytics Collaboration found that from 2008 to 2012, 46% of E. coli cases came from beef, 18% of salmonella cases came from seeded vegetables, and 66% of campylobacter cases came from dairy products.8
Recent developments on causes of food poisoning
Leafy green vegetables such as lettuce and spinach are one of the top sources of food poisoning, according to a January 2013 report from the US Centers for Disease Control and Prevention.
The US Centers for Disease Control and Prevention says in a June 2014 report that food workers touching ready-to-eat dishes in restaurants are frequently the source of norovirus gastroenteritis outbreaks.
The US Centers for Disease Control and Prevention found that rates of infection rose in 2012 compared with previous years.
Symptoms of food poisoning
Four well-known, classic symptoms are typical of gastroenteritis:1
- Diarrhea (loose stools)
- Nausea (feeling sick or 'queasy')
- Vomiting ('throwing up')
- Abdominal pain ('stomach cramps').
These symptoms generally have a sudden (acute) onset, but this, and symptom severity, can vary.1
The onset of symptoms after eating contaminated food can be within a few hours, but the incubation period can also be much longer, depending on the pathogen involved.4
Any vomiting resulting from food poisoning generally lasts for about a day, while any diarrhea may last for two or three days.
In addition to the classic symptoms above, food poisoning and gastroenteritis can also bring about:1,4
- Loss of appetite and weight loss
- Fever - high temperature and 'chills'
- Muscle pain - which may also produce a reflex spasm known as muscle guarding.
The type of gastrointestinal disturbance is a clue to the type of infection - viral infection generally produces diarrhea without blood or mucus, and watery diarrhea is the prominent symptom. Conversely, mucus and blood are typically seen in bacterial diarrhea.1
Other examples of symptoms specific to the causative pathogen include norovirus (causes acute onset of vomiting, especially in children), and adenovirus (causes diarrhea that can last for one or two weeks).1
One of the dangers of food poisoning and gastroenteritis - especially in very young, old or otherwise vulnerable people - is the loss of fluids resulting from diarrhea and vomiting, which can lead to dehydration.1,2 Dehydration can, however, be prevented.
On the next page, we look at tests and diagnosis of gastroenteritis and food poisoning, treatment options and ways in which to prevent and avoid getting food poisoning.