Multifocal Equine Influenza Outbreak with Vaccination Breakdown in Thoroughbred Racehorses

Gildea, Sarah; Garvey, M. B.; Lyons, P.A.; Lyons, Rachel; Gahan, Jacinta; Walsh, Cathal; Cullinane, Ann

doi:10.3390/pathogens7020043

Cited by 23 publications

(36 citation statements)

References 42 publications

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“…As antigenic drift in the HA and NA genes could result in amino acid changes in the respective proteins, the antigenicity of the virus may suffer changes . Equine Influenza vaccine breakdown has been described in Japan among racehorses vaccinated 3 months before the occurrence of an outbreak, and in Ireland in a multifocal outbreak of EI . During the EI outbreak in Argentina, 61% of the affected horses had up‐to‐date vaccination records, in concordance with SENASA regulations .…”

Section: Discussionmentioning

confidence: 83%

“…Six of the affected facilities were Thoroughbred racecourses while three and seven were polo and horse jumping clubs, respectively. Large and multifocal outbreaks of EI are often associated with the commingling of horses at equestrian events and their subsequent dispersal over a wide geographical area . During this outbreak, the movement of horses, competitions and equestrian events were not officially restricted, favouring the spread of the virus throughout the country.…”

Section: Discussionmentioning

confidence: 99%

“…Like other Influenza A viruses, EIV undergoes antigenic drift leading to vaccine breakdown . Since 2010, the OIE‐ESP recommendations have included both Florida clades 1 and 2 sublineages strains in EI vaccines .…”

Section: Introductionmentioning

confidence: 99%

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Multifocal outbreak of equine influenza in vaccinated horses in Argentina in 2018: Epidemiological aspects and molecular characterisation of the involved virus strains

Perglione

Vissani

Alamos

et al. 2019

Equine Veterinary Journal

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Summary Background Equine influenza is an important cause of respiratory disease of horses worldwide. The equine influenza virus (EIV) undergoes antigenic drift through the accumulation of amino acid substitutions in the viral proteins, which may lead to vaccine breakdown. Objectives To describe the epidemiological findings and the molecular characteristics of the EIV detected during the multifocal outbreak that occurred in Argentina between March and July 2018 and evidence a vaccine breakdown. Study design Observational, descriptive study. Methods Virus was detected in nasopharyngeal swabs using real‐time reverse transcriptase PCR (RT‐PCR). Nucleotide and deduced amino acid sequences of the haemagglutinin (HA) and neuraminidase (NA) genes were obtained from EIV positive nasopharyngeal swabs, and phylogenetic analysis was undertaken. Amino acid sequences were compared against the current World Organisation for Animal Health (OIE)‐recommended Florida clade 1 vaccine strain and strain components of vaccines used in Argentina. Serum samples were tested using haemagglutination inhibition test. Results Equine influenza virus infection was confirmed using real‐time RT‐PCR and serological testing. The phylogenetic analysis of the HA and NA genes revealed that all the EIV identified during the outbreak belong to the H3N8 subtype, Florida clade 1. Multiple amino acid changes, some of them at antigenic sites, were observed in the circulating virus when compared with the strains included in the most commonly used vaccine in Argentina. Seventy‐six percent of the affected horses had been vaccinated with this vaccine, suggesting the occurrence of vaccine breakdown. Main limitations The study does not include antigenic characterisation and full genome sequencing of Argentinian strains, that could provide additional information. Conclusions The occurrence of this multifocal equine influenza outbreak in regularly vaccinated horses is a field evidence of vaccine breakdown, reinforcing the necessity of keeping vaccine strains updated according to OIE recommendations. It also underlines the importance of the implementation of appropriate quarantine measures and restriction of horse movement in the face of disease.

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Section: Discussionmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 99%

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Multifocal outbreak of equine influenza in vaccinated horses in Argentina in 2018: Epidemiological aspects and molecular characterisation of the involved virus strains

Perglione

Vissani

Alamos

et al. 2019

Equine Veterinary Journal

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“…Later in 2014, EIV outbreaks were reported in 19 premises of Ireland. Though there was clear vaccination history against EIV which may be due to the non-updation of vaccines with Clade 2 of the Florida sublineage (Gildea et al, 2018 ). Phylogenetic analysis of HA and NA gene of Greek EIV isolates recovered during the year 2003–2007 showed that they are related to Eurasian lineage and Florida sublineage clade 2, respectively.…”

Section: Epidemiology and Evolutionmentioning

confidence: 99%

A Comprehensive Review on Equine Influenza Virus: Etiology, Epidemiology, Pathobiology, Advances in Developing Diagnostics, Vaccines, and Control Strategies

et al. 2018

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Among all the emerging and re-emerging animal diseases, influenza group is the prototype member associated with severe respiratory infections in wide host species. Wherein, Equine influenza (EI) is the main cause of respiratory illness in equines across globe and is caused by equine influenza A virus (EIV-A) which has impacted the equine industry internationally due to high morbidity and marginal morality. The virus transmits easily by direct contact and inhalation making its spread global and leaving only limited areas untouched. Hitherto reports confirm that this virus crosses the species barriers and found to affect canines and few other animal species (cat and camel). EIV is continuously evolving with changes at the amino acid level wreaking the control program a tedious task. Until now, no natural EI origin infections have been reported explicitly in humans. Recent advances in the diagnostics have led to efficient surveillance and rapid detection of EIV infections at the onset of outbreaks. Incessant surveillance programs will aid in opting a better control strategy for this virus by updating the circulating vaccine strains. Recurrent vaccination failures against this virus due to antigenic drift and shift have been disappointing, however better understanding of the virus pathogenesis would make it easier to design effective vaccines predominantly targeting the conserved epitopes (HA glycoprotein). Additionally, the cold adapted and canarypox vectored vaccines are proving effective in ceasing the severity of disease. Furthermore, better understanding of its genetics and molecular biology will help in estimating the rate of evolution and occurrence of pandemics in future. Here, we highlight the advances occurred in understanding the etiology, epidemiology and pathobiology of EIV and a special focus is on designing and developing effective diagnostics, vaccines and control strategies for mitigating the emerging menace by EIV.

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“…For example, clade 1 viruses were responsible for the outbreaks in Japan and Australia in 2007 (Cowled, Ward, Hamilton, & Garner, ; Yamanaka, Niwa, Tsujimura, Kondo, & Matsumura, ) whereas clade 2 viruses were involved in the Mongolia outbreak in 2008 and the India outbreak in 2009 (Virmani et al, ; Yondon et al, ). Furthermore, in the 2014 equine influenza outbreaks, clade 1 viruses were detected in the USA (OIE, ; Sreenivasan et al, ) while clade 2 viruses were detected in France, Germany, Ireland, Sweden and the UK (Fougerolle et al, ; Gildea et al, ; Rash et al, ).…”

Section: Introductionmentioning

confidence: 99%

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

Toh

Soh

et al. 2019

Transbound Emerg Dis

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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.

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Multifocal Equine Influenza Outbreak with Vaccination Breakdown in Thoroughbred Racehorses

Cited by 23 publications

References 42 publications

Multifocal outbreak of equine influenza in vaccinated horses in Argentina in 2018: Epidemiological aspects and molecular characterisation of the involved virus strains

Multifocal outbreak of equine influenza in vaccinated horses in Argentina in 2018: Epidemiological aspects and molecular characterisation of the involved virus strains

A Comprehensive Review on Equine Influenza Virus: Etiology, Epidemiology, Pathobiology, Advances in Developing Diagnostics, Vaccines, and Control Strategies

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

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