Submitted to: BioMed Central (BMC) Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/17/2016
Publication Date: 11/22/2016
Publication URL: http://handle.nal.usda.gov/10113/5695353
Citation: Spackman, E., Pantin Jackwood, M.J., Kapczynski, D.R., Swayne, D.E., Suarez, D.L. 2016. H5N2 highly pathogenic avian influenza viruses from the US 2014-2015 outbreak have an unusually long pre-clinical period in turkeys. BioMed Central (BMC) Veterinary Research. 12:260. doi:10.1186/s12917-016-0890-6.
Interpretive Summary: One of the most devastating outbreaks of highly virulent bird flu affected the US from December 2014 through June 2015. The economic losses to the US economy have been estimated to be $3.3 billion. The strain of bird flu which caused the outbreak was a novel virus strain. The biological characteristics of the virus were investigated with turkeys, which were heavily impacted by the outbreak in the Midwest. It was discovered that the strain causing the outbreak had some unusual features in that the turkeys would become infected, but did not appear sick until a short time before death. However, during this time they were excreting high levels of virus into the environment, particularly in their manure. This possibly contributed to the spread of the virus during the outbreak because infected turkeys were not easy to recognize, but are contaminating their environment early after infection.
Technical Abstract: From December 2014 through June 2015, the US experienced the most costly highly pathogenic avian influenza (HPAI) outbreak to date. Most cases in commercial poultry were caused by an H5N2 strain which was a reassortant with 5 Eurasian lineage genes, including a clade 126.96.36.199 goose/Guangdong/1996 lineage hemagglutinin, and 3 genes from North American wild waterfowl low pathogenicity avian influenza viruses. The outbreak primarily affected turkeys and table-egg layer type chickens. Three isolates were selected for characterization in turkeys: the US index isolate from December 2014 (A/northern pintail/WA/40964/2014), and two poultry isolates from April 2015(A/chicken/IA/13388/2015 and A/turkey/MN/12528/2015).