Strategic implementation of vaccines for control of equine influenza

Daly, Janet M.

doi:10.1111/evj.12794

Cited by 6 publications

(10 citation statements)

References 9 publications

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“…A possible explanation of that fact could be the occurrence of vaccine breakdown, related to the use of vaccines that contain out‐of‐date EIV strains. The efficacy of vaccines relies on the antigenic relatedness between the vaccine and the circulating field strains . 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 .…”

Section: Discussionmentioning

confidence: 99%

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: 99%

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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“…These implications meant that vaccinated horses could both shed the virus and become infected with the virus 25 . Therefore, the transmission rate, β , the latent period, , and the recovery rate, satisfied the following conditions: , , and .The probability of transmission () was reduced by 50% if at least one of the participating horses in the contact event (either a susceptible horse or an infectious horse) was vaccinated 29,32,51 .The model did not include waning immunity since waning immunity is not expected to occur until approximately 6 months after vaccination and the model was only run for 1.5 months 27,52 .The isolation period was always longer than the infectious period. Therefore, at the end of the isolation period, all horses were assumed to be fully recovered (i.e.…”

Section: Methodsmentioning

confidence: 99%

“…The model did not include waning immunity since waning immunity is not expected to occur until approximately 6 months after vaccination and the model was only run for 1.5 months 27,52 .…”

Section: Methodsmentioning

confidence: 99%

Comparing the effects of non-homogenous mixing patterns on epidemiological outcomes in equine populations: A mathematical modelling study

Milwid

O’Sullivan

Poljak

et al. 2019

Sci Rep

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Disease transmission models often assume homogenous mixing. This assumption, however, has the potential to misrepresent the disease dynamics for populations in which contact patterns are non-random. A disease transmission model with an SEIR structure was used to compare the effect of weighted and unweighted empirical equine contact networks to weighted and unweighted theoretical networks generated using random mixing. Equine influenza was used as a case study. Incidence curves generated with the unweighted empirical networks were similar in epidemic duration (5–8 days) and peak incidence (30.8–46.4%). In contrast, the weighted empirical networks resulted in a more pronounced difference between the networks in terms of the epidemic duration (8–15 days) and the peak incidence (5–25%). The incidence curves for the empirical networks were bimodal, while the incidence curves for the theoretical networks were unimodal. The incorporation of vaccination and isolation in the model caused a decrease in the cumulative incidence for each network, however, this effect was only seen at high levels of vaccination and isolation for the complete network. This study highlights the importance of using empirical networks to describe contact patterns within populations that are unlikely to exhibit random mixing such as equine populations.

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“…Complete genomic sequences of both the vaccine strains namely A/equine/Yokohama/aq13/2010 and A/equine/Ibaraki/1/2007 that is being used in the vaccine strain in Japan from 2016 has been published very recently (Nemoto et al, 2018 ). Vaccines must be administered strategically and appropriately to obtain optimum immune response and desired protection against EIV in equines (Daly and Murcia, 2018 ).…”

Section: Prevention and Controlmentioning

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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Strategic implementation of vaccines for control of equine influenza

Cited by 6 publications

References 9 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

Comparing the effects of non-homogenous mixing patterns on epidemiological outcomes in equine populations: A mathematical modelling study

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

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