Journal Article

Evaluating the Impact of Low-Pathogenicity Avian Influenza H6N1 Outbreaks in United Kingdom and Republic of Ireland Poultry Farms during 2020

Ronan, Stephanie, Bailie, Valerie B., Jeffers, Adam, Byrne, Christina, Núñez, Alejandro, Reid, Scott M., McMenamy, Michael J., Fusaro, Alice, Connaghan, Emily, Fanning, June, Barrett, Damien, Moriarty, John, James, Joe, McKenna, Robyn, McCullough, Kelly, Banyard, Ashley C., Lean, Fabian Z. X., Hansen, Rowena, Monne, Isabella, Terregino, Calogero, Cunningham, Ben, Brown, Ian H., Flynn, Orla, Byrne, Alexander M. P., Forsythe, Catherine, Lemon, Ken, Cuartero, Laura Garza

2024

Overview

In January 2020, increased mortality was reported in a small broiler breeder flock in County Fermanagh, Northern Ireland. Gross pathological findings included coelomitis, oophoritis, salpingitis, visceral gout, splenomegaly, and renomegaly. Clinical presentation included inappetence, pronounced diarrhoea, and increased egg deformation. These signs, in combination with increased mortality, triggered a notifiable avian disease investigation. High pathogenicity avian influenza virus (HPAIV) was not suspected, as mortality levels and clinical signs were not consistent with HPAIV. Laboratory investigation demonstrated the causative agent to be a low-pathogenicity avian influenza virus (LPAIV), subtype H6N1, resulting in an outbreak that affected 15 premises in Northern Ireland. The H6N1 virus was also associated with infection on 13 premises in the Republic of Ireland and six in Great Britain. The close genetic relationship between the viruses in Ireland and Northern Ireland suggested a direct causal link whereas those in Great Britain were associated with exposure to a common ancestral virus. Overall, this rapidly spreading outbreak required the culling of over 2 million birds across the United Kingdom and the Republic of Ireland to stamp out the incursion. This report demonstrates the importance of investigating LPAIV outbreaks promptly, given their substantial economic impacts.

• Publisher: MDPI AG
• Subject: Animals / Appetite loss / Asymptomatic / Avian flu / Avian influenza / avian influenza virus subtype H6 / Avian influenza viruses / Birds / broiler breeders / Chickens - virology / deformation / Diarrhea / Disease / Disease Outbreaks - veterinary / Economic aspects / eggs / Epidemics / etiological agents / Farms / flocks / Genetic engineering / Genetic relationship / genetic relationships / Genomes / Gout / Great Britain / H6N1 outbreaks / Health aspects / impact of LPAIV / Infections / Influenza / Influenza A virus / Influenza A virus - classification / Influenza A virus - genetics / Influenza A virus - pathogenicity / Influenza in Birds - epidemiology / Influenza in Birds - virology / Ireland - epidemiology / Irish Republic / Livestock farms / low-pathogenicity avian influenza virus / Mortality / Northern Ireland / Outbreaks / Pathogenicity / Phylogenetics / Phylogeny / Physiological aspects / Poultry / Poultry - virology / Poultry Diseases - epidemiology / Poultry Diseases - virology / Poultry farming / RNA polymerase / Salpingitis / Social aspects / Splenomegaly / Surveillance / United Kingdom - epidemiology / Virulence / Viruses