Evolution of equine influenza viruses (H3N8) during a Brazilian outbreak, 2015

Revista de microbiologia

Fernandes, Wilson Roberto¹  Favaro, Patricia Filippsen² 

[1] Ministério da Agricultura, Pecuária e Abastecimento, Campinas, Brazil;Universidade de São Paulo, São Paulo, Brazil

关键词: Equine influenza;    H3N8;    Hemagglutinin;    Neuraminidase;    Evolutionary analysis.;   

DOI  :  10.1016/j.bjm.2017.07.003

学科分类：农业科学（综合）

来源: Sociedade Brasileira de Microbiologia / Brazilian Society for Microbiology

【 摘 要 】

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 The use of an out of date vaccine strain or updated vaccines without the production of protective antibody titers might be the major contributing factors on virus dissemination during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.

【 授权许可】

CC BY-NC