ЕPIDEMIOLOGICAL SITUATION IN THЕ RЕPUBLIC OF BЕLARUS BY THE INCIDЕNCE OF TUBЕRCULOSIS

Abstract

Influenza is an extremely contagious acute viral disease caused by three antigenically independent viruses A, B and C. Influenza epidemics are caused by types A and B. Influenza A virus is divided into subtypes depending on the characteristics of the two surface antigens hemagglutinin (N) and neuraminidase (N) . Diseases in children are caused by various combinations of three subtypes of hemagglutinin (H1, H2 and H3) and two subtypes of neuraminidase (N1 and N2). Influenza A and B viruses are characterized by a constant variability of antigens, which can lead to the appearance of slight differences within existing antigens or result in the formation of new antigens. The second form of variability occurs only in influenza A and occurs relatively rarely with an interval of 10 or more years, while the first is observed in influenza A and B viruses almost annually.