Stomach Flu vs. Food Poisoning: What Is the Difference?

Listeria is bacteria that can cause a disease known as listeriosis.

What is the stomach flu (viral gastroenteritis)?

• People use the term "stomach flu" to refer to a feeling of being sick with unpleasant symptoms such as:
  • Fever
  • Nausea
  • Vomiting
  • Abdominal (stomach) cramping or pain
  • Diarrhea
• It can be hard to know exactly what is causing these symptoms. All of them can occur due to an infection and inflammation of the gastrointestinal tract (GI) most commonly caused by a virus known as viral gastroenteritis. This condition is sometimes referred to as "stomach flu" or a "stomach bug." Even though both the "flu" (influenza) and viral gastroenteritis are illnesses caused by a virus, the "stomach flu" or "stomach bug" (viral gastroenteritis) is not related to the actual influenza (flu) virus.

What is food poisoning?

• Food poisoning is more common than stomach flu. It is a food-borne disease that causes symptoms and signs that are similar illness to the stomach flu.
• Symptoms include:
  • Abdominal (stomach) cramping and pain
  • Diarrhea (watery)
  • Nausea
  • Vomiting
  • Pain
  • Fever
• This type of poisoning results when organisms (viruses, bacteria, parasites, or prions) or the toxins produced by the organisms, contaminate foods or beverages. This type of poisoning also is known as a foodborne illness or foodborne disease.

Is the stomach flu contagious, and how is it spread?

• The stomach flu virus is contagious. This means that the virus is spread from person to person.
• This "flu" is most common during the winter months (November to April in the U.S.).
• Direct contact with a person infected with a stomach bug can spread the disease, as can contact with the stool or vomit of a person infected with the virus.
• Outbreaks of the infection can occur in schools or toddler and child daycare settings. Other outbreaks have been reported on cruise ships (norovirus) and other places where people are gathered in close quarters (like dorms or military barracks).

Is food poisoning contagious, and can you get it from another person?

• Most food poisoning is not contagious. You get it when you eat foods or drinks contaminated with bacterium, viruses, or fungus, for example:
  • Raw meats
  • Seafood and sushi
  • Some mushrooms

However, some forms of poisoning are spread through contact with the infected bodily fluid (stool in particular-the "fecal-oral" route, which means a person has contaminated feces on their hand or hands and then touches their mouth with the portion of the hand with the infected feces).

Common food poisoning infection that comes from E. coli include ground beef, egg, raw meat, fresh produce, and more.

How do you get the stomach flu?

• Viral gastroenteritis most often is caused by an infection with a virus.
• Rotavirus infection is the leading cause of diarrhea in children worldwide, and it also infects people in nursing homes.
• Another common virus type responsible for stomach flu is noroviruses. Norovirus outbreaks have been reported in schools and on cruise ships.
• Other causes are adenoviruses and Astrovirus.

How do you get food poisoning?

• There are many different causes of food poisoning (more than 200).
• Contamination can occur at many stages of food preparation such as harvesting, processing, storing, shipping, cooking, or serving.
• Contamination can occur when food handlers do not properly clean their hands before working with or serving food (an infection spread by the fecal-oral route).
• Often, Escherichia coli (I) and Staphylococcus are the types of bacteria that lead to the contamination of the food. Other bacteria that cause food poisoning are Campylobacter, Vibrio cholerae (that bacterium that causes cholera), Salmonella, Listeria, botulism, and Shigella. Some bacteria also produce toxins in the contaminated foods that cause the disease.
• You can get this disease when you consume undercooked or raw meats, but it also has been reported after eating:
  • Raw and undercooked eggs
  • Unpasteurized cheeses
  • Raw fish or shellfish
  • Raw sprouts
  • Unpasteurized beverages
• Drinking contaminated water with bacteria also can lead to this disease.
• Vegetables and fruits also can be the source of poisoning if they have been contaminated while handling.

What are the signs and symptoms of the stomach flu, and when do they begin?

Symptoms of viral gastroenteritis can begin anywhere from 4 to 48 hours (a half a day or two) after exposure to the virus.

The most common symptoms of this health condition include:

• Nausea
• Vomiting
• Diarrhea
• Abdominal (stomach) pain or cramping

Other possible symptoms can include:

• Fever
• Chills
• Sweating
• Joint or muscle aches
• Loss of appetite
• Weight loss

If the health condition persists, dehydration can result, leading to symptoms and signs such as:

• Dizziness
• Decreased urine output
• Dry mouth
• Dark urine
• Excessive thirst
• Low blood pressure

Infants with dehydration may have:

• Dry diapers
• Sunken eyes and soft spots on the skull (fontanelles)
• Decreased tears when crying

What are the signs and symptoms of food poisoning, and when do they begin?

Signs and symptoms of this type of poisoning are similar to those of the stomach flu; however, are often more severe. Food poisoning symptoms usually begin within an hour or 2, or up to 12 hours (1/2 day) of eating or drinking the contaminated food.

Symptoms include:

• Nausea
• Vomiting
• Diarrhea (watery)
• Muscle aches and pains
• Fever
• Chills
• Stomach pain and cramping
• Fatigue
• A general sense of feeling unwell

Vomiting blood or blood in the stool may occur in particularly severe cases. Similar to the stomach flu, symptoms of dehydration as mentioned previously can develop over time if the poisoning symptoms persist. If you are vomiting blood or have blood in your stool (rectal bleeding) see your medical doctor or health care professional immediately.

• The duration of the stomach flu can vary. The symptoms may get better after a few days, but in some cases, a person may be sick with the infection can last for several days, up to 10.
• Food poisoning symptoms usually last anywhere from several hours, 1-2 days, or up to several days. The duration of this type of poisoning typically is shorter than the stomach flu.

How do I know if I have the stomach flu?

• Specific tests for the stomach flu usually are not ordered, and the diagnosis is suggested by the signs and symptoms described to the doctor by the patient, for example, pain or cramping in the stomach, diarrhea, and fever.
• Stool samples can be sent for cultures or other tests to identify the exact organism that is causing the illness, but this usually is not done unless the patient has blood in his or her stool. If a patient is vomiting blood or has blood in the stool, he or she should contact a medical doctor or health care professional immediately.

How do I know if I have food poisoning?

• The diagnosis of food poisoning also usually is made by a doctor observing the patient for the typical signs and symptoms of this type of poisoning (for example, diarrhea, fever, and pain or cramping in the stomach), and specific tests are usually not ordered. The history of the disease is important, since multiple people who ate or drank the same foods or beverages may become ill.
• Stool cultures are one of the few ways to pinpoint the type of bacteria, virus, fungi, or prion that caused the poisoning.

What can relieve symptoms or cure food poisoning?

• Natural or home remedies for the stomach flu include steps to ensure that the patient is taking in enough fluid and electrolytes to replace what is lost through vomiting and diarrhea.
• Adults with the infection can drink sports drinks, but these should not be used on a child or infant. There are special fluid and electrolyte solutions or ice pops for a child, toddler, or infant suffering from dehydration.
• It's important to drink lots of liquids in small amounts, and not force large amounts of fluid. Juices and colas are not recommended because the sugars they contain can be harsh on the stomach.
• Once you are able to eat, try to eat foods that are bland, and that is unlikely to be irritating to the stomach.
• Try foods such as:
  • Cereals
  • Bread
  • Potatoes
  • Lean meats
  • Plain yogurt
  • Fresh apples, and bananas
• Eating foods on the BRAT diet also are recommended if you are sick with the stomach flu because they also are easy on the stomach.
• Medical treatment or care by a doctor and medications for the infection typically is not necessary. Most cases are due to viral infection, and antibiotics are not necessary. Certain infections with bacteria that may lead to stomach flu may require antibiotic treatment, but these are much less common than viral gastroenteritis. Treatment involves maintaining adequate fluid and electrolyte levels.
• In severe cases, the doctor or health care professional may order medical treatment of fluids and electrolytes to be administered through an IV, or intravenously (through a vein), at a medical clinic or emergency department.

What can relieve symptoms or cure food poisoning?

• Natural or home remedies for relief of food poisoning are also related to the necessity to keep well hydrated by drinking lots of fluids.
• After symptoms start and you begin to feel sick, it can be helpful to let the stomach settle and not eat or drink for a few hours, unless you have severe vomiting or diarrhea. As previously mentioned, sports drinks and pediatric hydration solutions can be used to replace lost fluid and electrolytes from diarrhea and vomiting. Some people may find it helpful to suck on ice chips or take small sips of water to rehydrate and avoid further stomach pain or cramping.
• When experiencing food poisoning, the best plan is to slowly start by eating and drinking bland and easy-to-digest foods (the BRAT diet) that are easy on the stomach when you feel ready to begin eating again. Examples include:
  • Toast
  • Soda crackers
  • Gelatin
  • Rice
  • Bananas.
  • Avoid high-fat or spicy foods
• There are no medications or medical treatments recommended for the poisoning. Severe dehydration may require IV and electrolyte replacement, as mentioned previously.

How can you prevent getting the stomach flu?

• The best way to prevent getting this type of "flu" is to avoid contact with anyone suffering from the disease (or any other type of flu or contagious illness).
• Wash your hands frequently if you have been around a person who is sick.
• A vaccine is available against rotavirus, one of the most common causes of this type of "flu."

How can you prevent getting food poisoning?

• Prevention of food poisoning involves careful attention to food storage and preparation. While it is not completely possible to prevent poisoning from contaminated food that was later sold, there are steps you can take to prevent food poisoning at home.
  • Keep the kitchen and your food prep area and kitchen tools clean.
  • Cook seafood and meats thoroughly to their recommended temperatures (it is recommended to not eat raw meat or seafood). Foodsafety.gov provides a chart that describes safe cooking temperatures for foods.
  • Refrigerate perishable foods.
  • Do not eat food if you think it may be spoiled.

• The prognosis for a person with the stomach flu generally is good, and most people recover without complications, and without any specific medical treatment by a doctor.
• Food poisoning also has a good prognosis, and most people recover easily in 1-2 days without long-term complications. However, in severe cases, the person may need medical treatment by a doctor or other health care professional.