Evolution of equine influenza viruses (H3N8) during a Brazilian outbreak, 2015.
Equine influenza is one of the major respiratory infectious diseases in horses. An equine influenza virus outbreak was identified in vaccinated and unvaccinated horses in a veterinary school hospital in São Paulo, SP, Brazil, in September 2015. The twelve equine influenza viruses isolated belonged to Florida Clade 1. The hemagglutinin and neuraminidase amino acid sequences were compared with the recent isolates from North and South America and the World Organisation for Animal Health recommended Florida Clade 1 vaccine strain. The hemagglutinin amino acid sequences had nine substitutions, compared with the vaccine strain. Two of them were in antigenic site A (A138S and G142R), one in antigenic site E (R62K) and another not in antigenic site (K304E). The four substitutions changed the hydrophobicity of hemagglutinin. Three distinct genetic variants were identified during the outbreak. Eleven variants were found in four quasispecies, which suggests the equine influenza virus evolved during the outbreak. The use of an out of date vaccine strain or updated vaccines without the production of protective antibody titers might be the major contributing factors on virus dissemination during this outbreak.
['Favaro|Patricia Filippsen|PF|', 'Fernandes|Wilson Roberto|WR|', 'Reischak|Dilmara|D|', 'Brandão|Paulo Eduardo|PE|', 'Silva|Sheila Oliveira de Souza|SOS|', 'Richtzenhain|Leonardo José|LJ|']
D019943:Amino Acid Substitution D000818:Animals D001938:Brazil D004196:Disease Outbreaks D019143:Evolution, Molecular D014644:Genetic Variation D005838:Genotype D019267:Hemagglutinin Glycoproteins, Influenza Virus D006734:Horse Diseases D006736:Horses D006762:Hospitals, Animal D053123:Influenza A Virus, H3N8 Subtype D009439:Neuraminidase D009975:Orthomyxoviridae D009976:Orthomyxoviridae Infections D017422:Sequence Analysis, DNA D014764:Viral Proteins
Equine influenza H3N8 Hemagglutinin Neuraminidase Evolutionary analysis