There are about 1 billion a year of acute infectious gastroenteritis episodes that affect children under five in the world. Among the most common symptoms, acute diarrhea (characterized by at least three discharges in a day), which manifests itself as a result of exposure to a pathogen, usually a virus, bacteria or parasites, responsible for altering intestinal absorption and / or secretion, resulting in an increase in the volume of water in the colon that cannot be absorbed. Diarrhea in fact almost always occurs with at least one of the following four mechanisms in the intestine: alteration of osmotic forces, increase in normal secretory processes, destruction of epithelial cells or tight epithelial junctions, or motility disorders.
The most frequent viruses are rotavirus, norovirus, adenovirus, and cytomegalovirus.
The first of these is responsible for the most severe and common form of gastroenteritis, which affects children under five. Only in Italy, it is estimated that it causes about 300,000 cases of gastroenteritis per year. Particularly in the youngest (between 6 and 24 months), the virus can cause severe diarrhea and dehydration. According to data published on Eurosurveillance, two million children are hospitalized for a rotavirus infection every year worldwide. It is estimated that globally it is responsible for at least 20% of diarrhea deaths in the under-five. However, it should be emphasized that in Italy this infection is hardly so dangerous, even if it must never be underestimated. The virus has peaks of seasonal incidence which, in our latitudes, occur in the winter period between November and March. Unlike other pathologies, having once become ill does not protect against future infections, even if, with growth, they occur in an increasingly mild way.
Among the bacteria, there are numerous causes of gastroenteritis, including salmonella and escherichia coli.
Salmonella is one of the most common bacteria among those responsible for food poisoning. It is found in the intestines of reptiles, birds, and mammals, so pay attention to hygiene when handling the eggs. The symptoms of salmonellosis are diarrhea, vomiting, and abdominal cramps. Escherichia coli strains produce a potent toxin responsible in humans for important diseases. The infection is transmitted through the ingestion of contaminated food or water or by direct contact with the animals. At-risk raw or undercooked meat, unpasteurized milk, cheese and other derivatives based on unpasteurized milk. Even vegetables (fruit, vegetables, and sprouts) and fresh juices can carry the infection, as shown by the numerous epidemics linked to these types of food (spinach, lettuce, alpha-alpha shoots). This bacterium can also be passed from person to person (fecal-oral contamination), through close contact. Typical situations of contagion in the family, kindergartens, schools, and communities in general. The defense, here too, is hygiene.
Diarrhea in infants, non-infectious causes
The newborn must always be checked carefully. But before getting alarmed you need to be aware of some peculiarities related to the tender age. First, it is normal for infants to have frequent evacuations, even 4-6 times a day. In the case of breastfeeding, in particular, they are frequent and with foamy stools, especially if the baby does not receive solid food. In case of sudden onset of diarrhea, it must be kept in mind that the causes may not be infectious. In the case of mild and prolonged or recurrent symptoms for weeks or months, pathological conditions can be suspected including celiac disease, carbohydrate intolerance, and allergies. In celiac, disease malabsorption is the cause of the emission of abundant and malodorous feces. The doctor will know how to behave, but the first step in case of suspicion is to eliminate cereals and foods containing gluten. A not rare intolerance is lactose intolerance, generally due to the lack of an enzyme called lactase capable of digesting it. The improvement after the exclusion from the lactose diet or the use of lactose-free milk can confirm the suspicion. Also, in this case, the doctor will be able to make a diagnosis and provide a suitable diet. Diarrhea can also underlie allergic reactions. In this case, it is often associated with vomiting and blood in the stool. The use of the attending physician, in this case, is more than recommended.