Isolation and characterization of equine influenza virus (H3N8) from an equine influenza outbreak in Malaysia in 2015

Abstract

SummaryEquine influenza is a major cause of respiratory infections in horses and can spread rapidly despite the availability of commercial vaccines. In this study, we carried out molecular characterization of Equine Influenza Virus (EIV) isolated from the Malaysian outbreak in 2015 by sequencing of the HA and NA gene segments using Sanger sequencing. The nucleotide and amino acid sequences of HA and NA were compared with representative Florida clade 1 and clade 2 strains using phylogenetic analysis. The Florida clade 1 viruses identified in this outbreak revealed numerous amino acid substitutions in the HA protein as compared to the current OIE vaccine strain recommendations and representative strains of circulating Florida sub‐lineage clade 1 and clade 2. Differences in HA included amino acids located within antigenic sites which could lead to reduced immune recognition of the outbreak strain and alter the effectiveness of vaccination against the outbreak strain. Detailed surveillance and genetic information sharing could allow genetic drift of equine influenza viruses to be monitored more effectively on a global basis and aid in refinement of vaccine strain selection for EIV.

Genetic and serologic surveillance of canine (CIV) and equine (EIV) influenza virus in Nuevo León State, México

“…Six (75%) nasal fluid samples from trash service horses that presented characteristic symptoms of Influenza A virus were positive to matrix gene amplification. Although this percentage could be considered high, a recent study showed 96% of EIV detection in nasopharyngeal swabs from equines in Malaysia during an outbreak in 2015 (Toh et al, 2019).…”

Peer Review #2 of "Genetic and serologic surveillance of canine (CIV) and equine (EIV) influenza virus in Nuevo León State, México (v0.1)"

“…Six (75%) nasal fluid samples from trash service horses that presented characteristic symptoms of Influenza A virus were positive to matrix gene amplification. Although this percentage could be considered high, a recent study showed 96% of EIV detection in nasopharyngeal swabs from equines in Malaysia during an outbreak in 2015 (Toh et al, 2019). Although there are many viruses that infect the respiratory tract and they could induce similar symptoms, at present, symptoms such as conjunctivitis, runny nose and sneezing has been observed as the main symptoms related to the detection of CIV and EIV (Spickler, 2016;Sigh et al, 2018).…”