The stomach flu and food poisoning can be difficult to tell apart. The flu occurs when a virus infects the stomach and intestines. Food poisoning is caused by eating food that contains germs such as bacteria, viruses, or parasites. The two conditions have similar symptoms and may or may not have the same cause. They both usually resolve without medication or doctors visits, though some over-the-counter options can reduce symptoms.
Stomach flu is a common name for viral gastroenteritis, of which norovirus is the most common cause. Other viruses that can result in the illness include rotavirus, enteric adenovirus, and astrovirus. Norovirus causes 19 to 21 million illnesses, 56 to 71 thousand hospitalizations, 400,000 emergency department visits, and about two million outpatient visits each year. Onset for norovirus illness is usually short, between 24 and 48 hours, and lasts only 12 to 60 hours.
Food poisoning is a broad term and may be caused by viruses, bacteria, or parasites. Some people also develop illnesses from food due to allergies and overeating. Norovirus can cause food poisoning, as can salmonella and E. coli. Every year, about 48 million people in the United States experience food poisoning, and it causes around 3000 deaths per year. The average person in the United States will have food poisoning once every three or four years.
You can get viral gastroenteritis from airborne droplets of vomit containing viral particles, contaminated surfaces, or consuming contaminated food and water. Common foods linked to outbreaks are leafy greens, fresh fruits, and shellfish. The flu spreads very quickly between people. Norovirus is extremely stable in the environment; it can resist freezing temperatures, heating to 140 degrees and disinfection with chlorine or alcohol. Norovirus caused almost half of more than 2000 foodborne outbreaks between 2009 and 2012.
Germs can attach to foods in various ways. Sick people can spread germs to the food they cook if they do not wash their hands before touching the food. Germs already in or on food can infect people if the food is not washed or cooked enough. Germs from one food can also transfer to another food during preparation.
The stomach flu is common in closed communities such as nursing homes, schools, and cruise ships. Eating at restaurants and events with catered meals raises the risk of getting food poisoning. In addition to location, people with weakened immune systems are more likely to develop these conditions. Children and older people are also more susceptible to dehydration developing due to flu or food poisoning because they lose fluids rapidly from vomiting or diarrhea.
Symptoms of stomach flu appear within 48 hours and include nausea and vomiting, watery diarrhea, and abdominal pain. Some people develop headaches, muscle pain, fever, and fatigue. The stomach flu generally resolves quickly, as well, only lasting a few days to a week. Food poisoning has similar symptoms, which may appear within hours of eating the infected food, or as long as a few days later. They also include nausea, vomiting, watery or bloody diarrhea, belly pain, and fever.
Patients with stomach flu or food poisoning may require medical intervention if the condition leads to severe dehydration, abnormal renal function, bloody stools or rectal bleeding, weight loss, severe belly pain, or when symptoms last longer than a week. Additionally, anyone who was hospitalized or took antibiotics in the past six months, as well as those over the age of 65 and women who are pregnant should seek out medical attention for both conditions. An inability to eat or drink for an extended period and a fever higher than 100.4 degrees Fahrenheit also indicate more serious conditions requiring a doctor.
The best treatments for stomach flu and food poisoning are rest and drinking lots of water. Once the infected person feels they can keep down food, they should eat small, low-fat meals. Broth soups and juices can help replenish fluids, and saltine crackers are good for renewing salt levels. Excessive vomiting may call for medications so the person can ease fluid loss. Parents should avoid giving their children diarrhea medicines.
Both stomach flu and food poisoning are temporary and self-limiting, which means they resolve without treatment. People with medical conditions such as immunodeficiencies, inflammatory bowel disease, valvular heart disease, diabetes mellitus, renal impairment, rheumatoid arthritis, and lupus are more vulnerable and risk more serious complications. Generally, no long term issues result from food poisoning or the flu, and most patients make a full recovery. In rare cases, a person can develop post-infectious irritable bowel syndrome.
The best preventive measure for the stomach flu is adequate hand hygiene and avoiding close contact with people you know or believe might have gastroenteritis. A flu vaccine can help prevent serious or deadly infections caused by rotavirus. Good hand hygiene can also prevent food poisoning, as can food safety. People should generally avoid unpasteurized milk or foods made with it, wash fruits and vegetables well, cook meat and seafood until done, cook eggs until the yolk is firm, and wash hands, knives, and cutting boards after preparing any raw food.
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