Medycyna Wet. 62 (9), 981-986, 2006
Markowska-Daniel I., Kowalczyk A.
Influence of evolution on interspecies transmission of the influenza virus
The main purpose of the paper was to review information about the most important mechanisms of influenza virus evolution and their consequences for immunoprophylaxis and the elaboration of diagnostic tests. The influenza virus is the pathogen that indicates tropism on the epithelial cells of respiratory tract, responsible for frequent seasonal epidemics, caused by the rapid evolution of the viral genome. There are two main mechanisms of evolution: antigenic shift and genetic or antigenic drift. Hemagglutinnin, the protein of the virus envelope, is the main place of these variations. The study concerning receptor binding site structure and the specificity of human and animal influenza viruses have brought information about the mechanisms of interspecies spread of infections. It was confirmed that human influenza A viruses do not spread in birds while the species barrier between human and pigs is relatively low. Therefore pigs might functions as “mixing vessels” for the creation of new pandemic reassortants. The variability of the influenza virus is very complex process. Antigenic drift and shift still cause the origin of immunologically distinct strains of influenza viruses. The rapid antigenic drift of new forming viruses explain why there is a need for regular monitoring of that process. Antigenic and genetic characteristics of currently circulating strains of influenza virus could be beneficial in evaluating new diagnostic methods as well as for vaccine composition, which have to be updated annually.
Keywords: influenza virus, interspecies infections