Gastroenteritis is a contagious disease that spreads mainly via the fecal-oral route, notably by ingesting contaminated food or water, or by direct contact with an infected person. Symptoms such as vomiting and diarrhea may appear after the incubation period. It is essential to be aware of the modes of transmission to prevent contamination, especially in children and people at risk of complications.

Understanding gastroenteritis

Gastroenteritis is an inflammation of the digestive tract, often caused by a virus, bacteria or parasite. Rotavirus and norovirus are among the most common infectious agents. Symptoms include nausea, vomiting, diarrhea and sometimes fever.

Gastroenteritis is transmitted mainly via viral particles in stools that reach the gastrointestinal tract of another person. In other words, transmission is mainly fecal-oral. Viral particles may be present on hands, surfaces and objects contaminated by the stool or vomit of an infected person.

The disease is highly contagious and spreads easily, especially in places where people are in close contact, such as schools, day-care centers or nursing homes. A person suffering from gastroenteritis is generally contagious as soon as symptoms appear, and especially when they are most severe.

Contagion: how is the virus transmitted?

Gastroenteritis is transmitted mainly via the fecal-oral route, through direct contact with an infected person, but also indirectly, through contaminated surfaces or objects. 

For example, if an infected person touches objects or surfaces with his or her hands that carry particles of the microbe, the objects and surfaces become contaminated. If another person then touches these objects or surfaces, and then puts their fingers to their mouth, they can contract the virus through indirect contact.

Similarly, the virus is transmitted by direct contact with the infected person: for example, by shaking hands with or kissing someone who has viral or bacterial particles on their hands.

Other modes of transmission include ingestion of contaminated food or water, or contact with animals carrying the disease. 

Transmission of gastroenteritis in adults

In adults, transmission of gastroenteritis can be favored by specific factors. For example, poor hygiene can increase the risk of contamination, particularly in public places or at work. It is therefore crucial to wash your hands regularly, especially after using the bathroom and before eating or touching your face.

The presence of sick people in close proximity can also encourage the spread of the virus. It is recommended to limit physical contact with a person suffering from gastroenteritis to avoid transmission.

Finally, sharing personal objects can be a source of virus transmission. It is therefore advisable not to share objects such as towels, cutlery or toothbrushes.

How do you catch gastroenteritis from a close one?

Contagion of gastroenteritis within a family circle or between close friends is very common. Physical proximity and shared living spaces encourage transmission of the virus. Direct contact with a sick person, whether by hugging, kissing or using personal belongings (glasses, cutlery), can be a source of infection.

Indirect contact can also be a vector of contagion. Common objects (remote control, telephone, doorknobs) that have been touched by an infected person may contain particles of the microbe. If you touch these objects and then put your hands to your mouth, you run the risk of catching the disease.

Hand hygiene and disinfection are therefore essential to limit the spread of the disease within the same household.

Is it contagious before symptoms appear?

The incubation period for gastroenteritis, i.e. the time between exposure to the virus and the appearance of the first symptoms, generally varies from 24 to 72 hours. During this incubation phase, an infected person may already be contagious, although the risk of transmission is lower than once symptoms appear. This means that you can potentially transmit the disease even before you feel the first signs of infection.

Can you catch gastro through the air?

The question of airborne transmission of gastroenteritis is the subject of much debate. It is generally accepted that this type of transmission is possible, although it is not the most common. Studies have shown that droplets expelled by a sick person when sneezing or vomiting can contain the gastroenteritis virus and become airborne. These droplets can then be inhaled by another person, leading to possible infection.

However, it's important to stress that this is not the most common form of transmission. In fact, the main route of transmission of gastroenteritis is direct contact with an infected person or contaminated objects. As a result, the risk of contracting gastroenteritis through the air remains relatively low compared to that of direct contact.

What's more, some research has shown that certain types of gastro viruses, such as noroviruses, can spread by air over several meters. However, such cases remain relatively rare and require specific conditions to occur.

Incubation and contagion times

Incubation time for gastroenteritis

The incubation period for gastroenteritis, i.e. the time between exposure to the virus, bacteria or parasite and the appearance of the first symptoms, can vary. In general, the incubation period is estimated to be between 24 and 72 hours. However, depending on the pathogen involved, this period can extend to 10 days. During this phase, the infected person is not yet showing symptoms, but may already be contagious.

Period of contagion: how long does one remain contagious?

The duration of contagion varies according to the individual and the infectious agent involved. In general, a person suffering from gastroenteritis is considered contagious from the onset of symptoms or slightly before, and up to 48 hours after they have disappeared.

However, in some cases, contagion can be prolonged. For example, certain bacteria can keep a person contagious for up to 10 days after symptoms have disappeared.

It should be noted that even without symptoms, a person can still excrete the microbe and thus be contagious. This is why we recommend maintaining good hygiene practices, even after recovery.

Symptoms of gastroenteritis

Gastroenteritis generally manifests itself as a set of symptoms that appear suddenly. The most common are nausea, vomiting and diarrhea. Diarrhea is particularly profuse and watery, with at least three bowel movements in a 24-hour period.

Abdominal cramps may also be felt, sometimes accompanied by a low-grade fever. Some people may experience headaches and muscle aches. Fatigue and a feeling of general malaise or weakness may complete the picture.

It should be noted that these symptoms can vary from one person to another, depending on the body's resistance and the type of micro-organism responsible for the infection. For example, a person may experience diarrhea without vomiting, or vice versa.

Loss of appetite can also be a symptom of gastroenteritis. Dehydration can occur if fluid losses due to vomiting and diarrhea are not compensated for by adequate hydration.

Symptoms in children and babies

In children and babies, symptoms of gastroenteritis can sometimes be more severe. Common signs include vomiting, diarrhea and abdominal cramps. Children may also experience fever and headaches.

Child-specific symptoms may also appear. Affected children may be drowsy or disoriented, with dark, sunken eyes. In babies, a collapsed fontanel may indicate dehydration.

Particular attention should be paid to irritability, loss of appetite and fatigue.

Treatment of gastroenteritis

Home solutions for rehydration

For effective rehydration at home, there are several solutions available. For a simple and accessible option, water remains an excellent source of hydration. However, in the case of gastroenteritis, a rehydration solution is more effective.

You can make your own homemade rehydration solution. It can be made with :

• 360 ml (12 oz) pure orange juice, unsweetened

• 600 ml (20 oz) cooled boiled water

• ½ teaspoon (2.5 ml) salt

Be sure to mix ingredients well to obtain a homogeneous solution.

Home preparation of rehydration solutions requires precision, however, to avoid dosage errors.

What to eat during and after gastroenteritis?

Food plays a crucial role in helping the body recover from gastroenteritis. During this period, we recommend eating light, easily digestible foods.

• Vegetables: opt for well-cooked vegetables that are easy to digest and provide vitamins, such as carrots or zucchini.

• Meat and fish: opt for lean meats and grilled fish, which are easy-to-digest sources of protein.

• Starches: include foods such as rice and potatoes for their energy and low-fiber content.

• Fruit: fresh or canned fruit in juice (not syrup) is generally well tolerated.

• Avoid high-fiber foods such as raw vegetables, highly acidic foods and spicy dishes, which can irritate your digestive system. Avoid lactose-containing dairy products and high-fat foods, as well as caffeine and alcohol.

After gastroenteritis, it's advisable to gradually reintroduce solid foods into your diet. Eat small, frequent meals rather than large quantities all at once. The important thing is to listen to your body and let it recover at its own pace, but don't forget that eating remains an important part of your digestive tract's healing process.

Treatment for children and babies

Treatment of gastroenteritis in children and babies is primarily aimed at preventing dehydration. Rehydration is the first step, by offering suitable drinks on a regular basis. For infants, breast milk or infant formula is recommended. Oral rehydration solutions can also be used, especially in cases of severe diarrhea or vomiting. Your pharmacist can help you choose a rehydration solution and calculate the dose to give your child, based on weight and age.

You should also monitor your child's general condition. If symptoms worsen, or if the child is unable to keep fluids down, medical attention is required.

Medicines are generally reserved for certain forms of gastroenteritis, on medical advice. It is essential not to administer any medication without the advice of a health professional, as some may be contraindicated in young children. Your pharmacist can advise you on which medicines to give your child if necessary.

Preventing contamination by gastroenteritis

To prevent contamination by gastroenteritis, several measures can be adopted:

• Hand hygiene: frequent and thorough hand washing with warm, soapy water is crucial. This is particularly important before eating, after using the toilet, before touching your face and after contact with a sick person.

• Cleaning surfaces: as microbes can survive on inanimate surfaces, it is advisable to regularly clean frequently touched objects and surfaces. It's also important to clean toilets after each use by an infected person, not forgetting the door handle and flush.

• Avoid contact with sick people: if possible, avoid direct contact with people suffering from gastroenteritis.

• Take care with food and water: avoid consuming food or water that could be contaminated. This is particularly important when traveling abroad.

• Vaccination: a vaccine against certain viruses that can cause gastroenteritis is recommended for children. Ask your pharmacist for more information.