An infectious disease doctor explained the prevalence of norovirus in winter

Norovirus infection is an intestinal infection caused by an RNA-containing virus of the colcevirus family. Andrey Pozdnyakov, MD, PhD, an infectious disease doctor, chief physician of the clinical diagnostic laboratory INVITRO-Siberia, told Izvestia on January 25 about why it is in winter and what symptoms can be observed.

"Norovirus is transmitted by fecal-oral and contact. Sometimes airborne transmission mechanism is also possible, when the patient has massive vomiting - this is the main symptom of this disease. Accordingly, when vomiting, a suspension of the virus for some time is contained in the air, and a person can become infected by inhalation. But in any case, when inhaling the virus first gets on the mucous membrane of the oral cavity, and further as a result of the process of swallowing gets into the gastrointestinal tract, where the virus multiplies," - said the expert.

According to him, to suspect this infection can be suspected by a characteristic triad of symptoms: first of all there is vomiting, which is often the main and only symptom, and then fever and diarrhea.

"It is very characteristic of norovirus infection that a significant proportion of people in a collective or family become ill - it will not be a single case, several people are bound to be affected by the virus. It is quite contagious infection: according to different data, from 100 to 1 thousand smallest virus particles are enough for infection. That is, even the smallest microscopic amount of viral material is enough to infect a person," Pozdnyakov said.

The doctor specified that the susceptibility is universal - both adults and children are equally ill. Immunity is developed, but it is not persistent, which is due to the variability of this RNA-containing virus. Therefore, norovirus infection can be contracted several times a season. No vaccine has yet been developed against it.

"The high incidence in winter can be explained by the fact that norovirus infection perfectly tolerates low temperatures. The natural source is, among other things, water, which at low temperatures becomes a favorable reservoir for noroviruses. In it, the virus multiplies perfectly and persists for a long time, calmly tolerating even freezing. This is why, because low temperatures are optimal for norovirus, outbreaks occur in winter. Especially since bacterial infections are less common in winter, and no place is empty," Pozdnyakov said.

He added that noroviruses are quite resistant to standard disinfectants. For example, chlorine affects them only in very high concentrations, which are rarely used.

Sources of transmission are water, sick people and food - especially food that is not heat-treated. This infection can also tolerate high temperatures quite well.

The infectious disease doctor said that treatment is carried out at home, that is, outpatient. The exception is people with severe forms - most often children, in whom repeated vomiting prevails. Patients with dehydration and the inability to replenish fluid and electrolyte losses by mouth are hospitalized, and in infectious disease hospitals they are given infusion therapy.

Pozdnyakov said that nutrition during norovirus infection should exclude in the acute period (three to four days): dairy products, fresh fruits and vegetables, fatty, spicy, fried, smoked, canned food. There should be as sparing a diet as possible. Allowed boiled potatoes, boiled rice, vermicelli products, porridge on water or with minimal addition of milk (1/3 part); lean and non-spicy soups on beef and chicken broth, boiled meat, steamed beef and chicken cutlets and boiled vegetables.

"Another feature of norovirus infection, which accounts for its fairly active spread in the population, is that a clinically healthy patient remains a viral isolate for some time. A patient, whose symptoms have already gone, still excretes the virus with feces for at least two weeks. Accordingly, in case of poor hygiene (poor hand washing after toileting, shared toilets, shared towels), there is a contact route of transmission from re-valescents - people who have already recovered from the infection but are virus isolates. This contact route is very epidemiologically significant, as these patients are a source of infection for other people for a certain period of time", - said Pozdnyakov.

He emphasized that during the acute period the sick person should stay at home and, as far as possible, try to isolate. All common items and rooms should be disinfected. At the same time, the patient is allocated separate utensils. These measures can slow down the spread of infection.

Earlier, on January 21, a doctor-otolaryngologist of the medical company "SberZdorovye" Marina Evsikova told "Izvestia" that the mostcommon cause of acute sore throat is a viral infection, such as ARVI, lessoften inflammation of a bacterial nature. Acute pain in the throat is also the main sign of abscesses of the pharynx - a condition in which near the tonsils, on the sides of the pharynx or behind its mucous membrane forms a purulent cavity. Such abscesses can occur, for example, as a complication of a bacterial infection of the throat, and they are often accompanied by difficulty in opening the mouth, turning the head, as well as marked intoxication of the body.