Influenza

Biography

Biography: Ian Brown

Abstract

Global activity with animal influenza is dominated by persistence, spread, and re-emergence of H5 HPAI. Furthermore this group of viruses have undergone significant antigenetic evolution in recent years. These viruses have remained endemic in several regions whilst in others sustained eradication has been possible. A variety of control methods have been used with an increasing number of countries using vaccination as a single or multiple component where stamping out alone has not proved practical. Multiple clades of H5 HPAI continue to co-circulate and evolve in poultry populations and a several specific groups have been associated with continued zoonotic infection including a rise in cases in Egypt. In the last twelve months there have been developments on a global scale not previously seen. H5N1 virus has re-emerged in central Asia, West Africa and Eastern Europe. However, by far the greatest development of global significance has been the emergence of clade 2.3.4.4 viruses which have spread globally within Asia, Europe and for the first time in North America. To date these viruses appear to be of lower risk for humans but continue to evolve. All these events have revealed significant virus reassortment within the H5 HPAI Eurasian family. Incursion is postulated to have occurred initially via infected migratory waterfowl but the spread and transmission within poultry has most likely occurred through multiple pathways. This presents significant new challenges for the future since the basis for prevention of HPAI infection is through strong biosecurity. Other AI viruses continue to emerge and circulate including LPAI viruses; H7N9 of avian origin in China primarily in human’s since 2013 is noteworthy. Influenza A viruses from pigs are still occasionally associated with human infection most notably H3N2v in North America. A greater understanding of reverse zoonoses reveals these events to pigs occur on a frequent basis.