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Genetic evolution of equine influenza strains isolated in F rance from 2005 to 2010
Author(s) -
Legrand L. J.,
Pitel P.H. Y.,
Cullinane A. A.,
Fortier G. D.,
Pronost S. L.
Publication year - 2015
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/evj.12244
Subject(s) - clade , equine influenza , outbreak , biology , virology , virus , genome , whole genome sequencing , mutation , genetics , gene , phylogenetics
Summary Reason for performing this study Equine influenza virus ( EIV ) is considered the most economically important equine respiratory pathogen worldwide. The H3N8 subtype, responsible for all outbreaks of equine influenza globally, evolves perpetually. Mutations in the genome of these viruses have the potential to modify their antigenic properties and recognition by pre‐existing antibodies. Objectives The aim of this study was to determine the genetic evolution of EIV strains in F rance and to compare it with the evolution of strains isolated globally. Analysis of the sequence data was performed to investigate any possible links between the outbreaks. Study design Retrospective genetic analysis study of archived material. Methods Analyses were performed on the HA 1 domain of haemagglutinin H 3 of EIV isolated in a previous study carried out from N ovember 2005 to O ctober 2010. The nucleic acid sequence of 41 strains was analysed and translated. The F rench viruses were compared with 59 C lade 1 strains and 83 C lade 2 strains. Strains were aligned chronologically and on the basis of their geographical origin. Results The 16 C lade 1 strains are all derived from the outbreak that started in the G rosbois training yard in 2009. The virus genome appears to have been stable during the outbreak. The 25 C lade 2 strains were isolated over the 5‐year period during which several mutations had emerged. Some strains incorporate a sporadic mutation, and others a mutation that may occur several times but does not persist. However, all strains are gradually moving towards definitive mutations. Conclusion This study demonstrated that EI Vs have evolved in F rance during this period in a similar manner to EI Vs globally. The data lend support to the current W orld A nimal H ealth O rganisation recommendation that the vaccines contain a representative of both C lade 1 and C lade 2 of the F lorida sublineage. The Summary is available in Chinese – see Supporting information .