Up to 4 million people can consult for gastrointestinal illness each winter in France.
Gastro is a typical winter illness (although it can also occur in summer). After an incubation period of 24 to 72 hours, the first symptoms appear. Gastro is very contagious.
Map: how many cases of gastro at the moment?
To monitor gastroenteritis epidemics, the Sentinels network monitors cases of acute diarrhea observed in community medicine. Since March 2026, cases have been declining.
Definition: what is gastroenteritis?
Gastroenteritis results from inflammation of the digestive system (stomach walls and intestine) caused by:
- a virus (more common): norovirus most often in adults and rotavirus in children.
- a bacteria: the most common bacteria are Campylobacter, Salmonella, Shigella and Yersinia. It can also be enterotoxigenic Escherichia coli or Clostridium difficile,
- A parasite (like Giardia intestinalis.)
Food in case of gastro
As gastroenteritis directly affects the digestive system, transit is particularly disrupted and digestion is more than difficult. It is also important to choose your foods carefully when you suffer from diarrhea, nausea, vomiting and, more generally, stomach aches. For example, we favor rice, pasta, bananas… and we avoid anything that will attack the digestive system: raw fruit, raw vegetables, orange juice, soft drinks…
What is the incubation time of the virus?
This illness generally manifests itself 1 to 3 days after coming into contact with the virus. The incubation time varies depending on the type of bacteria or virus.
What are the symptoms of gastroenteritis?
- abdominal cramps
- stomach aches
- loss of appetite,
- nausea,
- vomiting,
- a slight fever (38°C),
- diarrhea (at least 3 loose or semi-liquid stools every 24 hours)
- fatigue
- sometimes a headache
- muscle pain
Symptoms appear suddenly, 12 to 24 hours after infection with the virus and are not necessarily present all together. As long as symptoms are present, the person is contagious.
What to do against diarrhea?
Diarrhea is a transit disorder which is characterized by soft, even liquid stools, in abnormally high quantities or with an increased frequency of occurrence, of the order of several times per day. Against diarrhea, you can:
► Eat pasta, rice, semolina, potatoes, salty broths.
► Avoid dairy products and raw vegetables and fruits.
► Stay well hydrated by drinking water or herbal teas to avoid dehydration linked to diarrhea
► Take treatment such as intestinal dressings (Smecta) and transit slowers combined with antipyretics in case of fever (Dolipane), antispasmodics (Spasfon), antiemetics in case of nausea and/or vomiting.
► Take oral rehydration solutions in children and the elderly to compensate for sodium leaks.
Gastroenteritis lasts 3 to 8 days, sometimes up to 10 days when it is of bacterial or parasitic origin.
Its symptoms being characteristic of gastro, this pathology is diagnosed quite easily, especially during a period of epidemic. No examination is necessary for a typical presentation. If symptoms persist for more than a week or if the symptoms are poorly tolerated, it is entirely possible to take a blood test and a stool examination (stool culture) to look for a possible bacterial infection. Rotavirus is identified in patient stools by immunology (ELISA tests) or by RT-PCR.
What treatments to treat gastroenteritis?
To treat gastroenteritis, there is nothing better than rest. For headaches, you should take analgesics such as paracetamol. Against stomach aches, a hot water bottle can provide relief. Against diarrhea:
► The intestinal anti-infective nifuroxazide (Ercéfuryl®) is indicated only in adults in cases of acute presumed bacterial diarrhea, but it is contraindicated in children under 18 years of age, requires a prescription, and its use is limited.
► Medicines based on clays, such as Smecta® (diosmeticte) available by prescription or as self-medication, can be used to treat acute diarrhea from the age of 2, with parallel rehydration and for a limited duration.
► In children under 2 years of age, the standard treatment for diarrhea is the administration of oral rehydration solution (ORS). ORS are sachets of powder to pour into a bottle of water, available in pharmacies without a prescription.
► Ultra-levure® can be taken by adults and children aged 6 and over.
Everywhere, oral rehydration remains essential, and you must alert a doctor if fever persists, blood in the stools, intense vomiting or signs of dehydration.
When to worry about gastro in babies?
Gastroenteritis should be closely monitored when it affects children, particularly infants. Rotaviruses are responsible for approximately half of severe diarrhea in infants requiring hospitalization. Vaccination against rotavirus is recommended in France for all infants. It requires 2 or 3 doses depending on the vaccine and must be started at 2 months and completed at 6 or 8 months at the latest.
The gastro virus is very contagious. It can be transmitted by contact with a sick person, but also by spit or by touching a contaminated object if it is viral gastroenteritis. To avoid catching gastroenteritis;
- Wash your hands frequently (soap and water, or hydro-alcoholic product)
- Clean surfaces touched by a sick person carefully and regularly. Some viruses (rotavirus and norovirus) are very resistant in the environment.
- Avoid busy places, such as transport or department stores, during epidemic periods.
- Wear a surgical mask to protect against viruses.
- Ventilate each room of your living space every day for at least 10 to 15 minutes in order to renew the air and prevent the spread of microbes.
