**5. Transmission**

The source of infection is a sick person in the acute stage of the disease, convalescent, or a virus carrier. Pathogens are secreted with nasopharyngeal secretions, sputum, conjunctival discharge, feces, and urine (mainly in individuals with immunosuppression). The timing of isolation of pathogens from the upper respiratory tract reaches the 25th day of illness onset and more than 1.5 months with feces. Adenoviral infections are transmitted by airborne, introducing the virus to the conjunctiva and possibly by the fecal-oral route, thus affecting not only the respiratory tract but also other organs. The widespread disease is 5–10% of all viral diseases. Incidence is recorded throughout the year with a rise in the cold season. Both sporadic cases and epidemic outbreaks are observed. The most susceptible to infection are children from 6 months to 5 years, as well as military personnel. Particularly it has a high incidence in the newly formed groups of children and adults (in the first 2–3 months). In 95% of the adult population, antibodies to the most common serotypes of the virus can be detected in the serum [20].
