title: A low-pathogenic avian influenza H6N1 outbreak in a turkey flock in France: a comprehensive case report.
abstract: Based on a case observed and investigated on a commercial turkey farm in western France in 81-day-old birds, we report the pattern of H6N1 low-pathogenic avian influenza in this species. Diseased birds displayed an acute severe dyspnoea, leading to death by asphyxia of more than 5% of the flock. The most specific pathological feature was a constant diffuse infraorbital sinusitis, along with a focal necrotic exudate inside the lumen of the upper respiratory tract, characterized microscopically as a mixed fibrinous and leucocytic material. Influenza A immunohistochemistry revealed an intense staining of epithelial cells in tracheas, bronchi, air sacs and their luminal necrotic material. While no primary bacterial infection could be detected from diseased turkeys, influenza H6 reverse transcription-polymerase chain reaction analysis performed on tracheal swabs tested positive. Direct sequencing and phylogenetic analysis of the eight segments showed that this H6N1 virus clustered closely within West European mallards' (group 3) H6 genotypes. A thorough analysis of genetic databases suggests that a regional waterfowl reservoir is likely to play a central role in H6 introductions in poultry farms, whose pathways remain to be elucidated.
authors.affiliation: Institut National de la Recherche Agronomique, UMR 1225 IHAP, Toulouse, France.
authors.forename: Léni
authors.initials: L
authors.lastname: Corrand
authors.forename: Maxence
authors.initials: M
authors.lastname: Delverdier
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Lucas
authors.forename: Guillaume
authors.initials: G
authors.lastname: Croville
authors.forename: Charles
authors.initials: C
authors.lastname: Facon
authors.forename: Dominique
authors.initials: D
authors.lastname: Balloy
authors.forename: Mariette
authors.initials: M
authors.lastname: Ducatez
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Guérin
mesh_terms: D000400:Air Sacs / Q000473:pathology / Q000821:virology; D000818:Animals; D001483:Base Sequence; D004196:Disease Outbreaks / Q000662:veterinary*; D017809:Fatal Outcome; D005602:France / Q000453:epidemiology; D005838:Genotype; D009980:Influenza A virus / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D005585:Influenza in Birds / Q000453:epidemiology* / Q000473:pathology* / Q000821:virology; D008168:Lung / Q000473:pathology / Q000821:virology; D008969:Molecular Sequence Data; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D017422:Sequence Analysis, DNA / Q000662:veterinary; D014132:Trachea / Q000473:pathology / Q000821:virology; D014422:Turkeys / Q000821:virology*
chemical_list: D012367:RNA, Viral