Overview of swine influenza virus vaccine research and technology: What's on the horizon and what do we need to move forward ?

摘要

Swine influenza represents a problem for the health of pigs and the economic health of the swine industry due to real and perceived public health risks. This is largely driven by the diversity of influenza A viruses (IAV) in swine herds. Antigenic drift (mutations) and shifts (reas-sortments) by influenza viruses are continually occurring. The RNA polymerase error rate among IAV is ~2 x 10~3 nucleotide substitutions/ site/year~1 and whenever a single cell is infected by 2 different influenza viruses,reassortment events between the viruses can occur and result in as many as 256 different gene combinations. These 2 types of genetic change provide the basis of the marked genetic and antigenic diversity in contemporary IAV in North American swine. In addition, interspecies transmission is an important contributor to the genetic diversity of IAV found in swine. For example, at least 23 separate human-to-swine transmission events of human seasonal HI and H3 influenza viruses have been identified globally since 1990.2