Using guinea pig as a model for evaluation of equine influenza vaccine

Equine influenza is a highly contagious viral disease, specially among 1-5 years old naive horses. Vaccination is considered the best way to control the disease spread and outbreaks. Although foals are the main animal used for evaluation of equine influenza vaccines, guinea pigs were chosen as an alternative model in the present work, as they have a negligible antibody titer against equine influenza virus and are cheaper and easier to handle than foals. Five equine influenza vaccine batches were evaluated in two animal models, foals and guinea pigs, by injection of two doses/animal with 4 weeks apart using 2 mL/animal/dose and evaluation of immune responses by hemagglutination inhibition test and enzyme-linked immunosorbent assay. On the 7th week post vaccination, equine influenza antibodies titers reached maximum values of 9-10.2 and 8.7-10 hemagglutination inhibition units for foals and guinea pigs, respectively; sample/negative ratios were 0.126-0.464 and 0.128-0.445 for both animals, respectively. The use of guinea pigs as an animal model for the evaluation of equine influenza vaccines could be recommended instead of foals.

La gripe equina es una enfermedad viral muy contagiosa, especialmente entre los caballos jóvenes de 1 a 5 años de edad. La vacunación se considera la mejor forma de controlar la propagación y los brotes de la enfermedad. Aunque los potros son el principal animal utilizado para la evaluación de vacunas contra la gripe equina, en el presente trabajo se eligieron cobayos como modelo alternativo, ya que tienen un título insignificante de anticuerpos contra el virus de la gripe equina y son más baratos y fáciles de manejar que los potros. Se evaluaron cinco lotes de vacunas contra la gripe equina en dos modelos animales, potros y cobayos, mediante la inyección de dos dosis/animal con 4 semanas de intervalo utilizando 2 mL/animal/dosis y la evaluación de las respuestas inmunitarias mediante la prueba de inhibición de la hemaglutinación y el ensayo inmunoenzimático. En la 7ª semana posvacunación, los títulos de anticuerpos contra la gripe equina alcanzaron valores máximos de 9-10,2 y 8,7-10 unidades de inhibición de la hemaglutinación para potros y cobayos, respectivamente; las relaciones muestras/negativos fueron de 0,126-0,464 y 0,128-0,445 para ambos animales, respectivamente. Podría recomendarse el uso de cobayos como modelo animal para la evaluación de vacunas contra la gripe equina, en lugar de potros.

Global epidemiology of Equine Influenza viruses: "A possible emerging zoonotic threat in future" an extensive systematic review with evidence / Epidemiologia global dos vírus da Gripe Equina: "Uma possível ameaça zoonótica emergente no futuro" uma extensa revisão sistemática com evidências

There are different opinions around the World regarding the zoonotic capability of H3N8 equine influenza viruses. In this report, we have tried to summarize the findings of different research and review articles from Chinese, English, and Mongolian Scientific Literature reporting the evidence for equine influenza virus infections in human beings. Different search engines i.e. CNKI, PubMed, ProQuest, Chongqing Database, Mongol Med, and Web of Knowledge yielded 926 articles, of which 32 articles met the inclusion criteria for this review. Analyzing the epidemiological and Phylogenetic data from these articles, we found a considerable experimental and observational evidence of H3N8 equine influenza viruses infecting human being in different parts of the World in the past. Recently published articles from Pakistan and China have highlighted the emerging threat and capability of equine influenza viruses for an epidemic in human beings in future. In this review article we have summarized the salient scientific reports published on the epidemiology of equine influenza viruses and their zoonotic aspect. Additionally, several recent developments in the start of 21st century, including the transmission and establishment of equine influenza viruses in different animal species i.e. camels and dogs, and presumed encephalopathy associated to influenza viruses in horses, have documented the unpredictable nature of equine influenza viruses. In sum up, several reports has highlighted the unpredictable nature of H3N8 EIVs highlighting the need of continuous surveillance for H3N8 in equines and humans in contact with them for novel and threatening mutations.

Existem diferentes opiniões em todo o mundo a respeito da capacidade zoonótica dos vírus da influenza equina H3N8. Neste relatório, tentamos resumir os resultados de diferentes pesquisas e artigos de revisão da literatura científica chinesa, inglesa e mongol relatando as evidências de infecções pelo vírus da influenza equina em seres humanos. Diferentes mecanismos de busca, como CNKI, PubMed, ProQuest, Chongqing Database, Mongol Med e Web of Knowledge geraram 926 artigos, dos quais 32 atenderam aos critérios de inclusão para esta revisão. Analisando os dados epidemiológicos e filogenéticos desses artigos, encontramos uma considerável evidência experimental e observacional de vírus da influenza equina H3N8 infectando seres humanos em diferentes partes do mundo no passado. Artigos publicados recentemente no Paquistão e na China destacaram a ameaça emergente e a capacidade dos vírus da influenza equina para uma epidemia em seres humanos no futuro. Neste artigo de revisão, resumimos os relatórios científicos relevantes publicados sobre a epidemiologia dos vírus da influenza equina e seu aspecto zoonótico. Além disso, vários desenvolvimentos recentes no início do século 21, incluindo a transmissão e estabelecimento de vírus da influenza equina em diferentes espécies animais, ou seja, camelos e cães, e presumida encefalopatia associada aos vírus da influenza em cavalos, documentaram a natureza imprevisível dos vírus da influenza equina. Em suma, vários relatórios destacaram a natureza imprevisível de H3N8 EIVs destacando a necessidade de vigilância contínua para H3N8 em equinos e humanos em contato com eles para novas mutações ameaçadoras.

Global epidemiology of Equine Influenza viruses; A possible emerging zoonotic threat in future an extensive systematic review with evidence

Abstract There are different opinions around the World regarding the zoonotic capability of H3N8 equine influenza viruses. In this report, we have tried to summarize the findings of different research and review articles from Chinese, English, and Mongolian Scientific Literature reporting the evidence for equine influenza virus infections in human beings. Different search engines i.e. CNKI, PubMed, ProQuest, Chongqing Database, Mongol Med, and Web of Knowledge yielded 926 articles, of which 32 articles met the inclusion criteria for this review. Analyzing the epidemiological and Phylogenetic data from these articles, we found a considerable experimental and observational evidence of H3N8 equine influenza viruses infecting human being in different parts of the World in the past. Recently published articles from Pakistan and China have highlighted the emerging threat and capability of equine influenza viruses for an epidemic in human beings in future. In this review article we have summarized the salient scientific reports published on the epidemiology of equine influenza viruses and their zoonotic aspect. Additionally, several recent developments in the start of 21st century, including the transmission and establishment of equine influenza viruses in different animal species i.e. camels and dogs, and presumed encephalopathy associated to influenza viruses in horses, have documented the unpredictable nature of equine influenza viruses. In sum up, several reports has highlighted the unpredictable nature of H3N8 EIVs highlighting the need of continuous surveillance for H3N8 in equines and humans in contact with them for novel and threatening mutations.

Resumo Existem diferentes opiniões em todo o mundo a respeito da capacidade zoonótica dos vírus da influenza equina H3N8. Neste relatório, tentamos resumir os resultados de diferentes pesquisas e artigos de revisão da literatura científica chinesa, inglesa e mongol relatando as evidências de infecções pelo vírus da influenza equina em seres humanos. Diferentes mecanismos de busca, como CNKI, PubMed, ProQuest, Chongqing Database, Mongol Med e Web of Knowledge geraram 926 artigos, dos quais 32 atenderam aos critérios de inclusão para esta revisão. Analisando os dados epidemiológicos e filogenéticos desses artigos, encontramos uma considerável evidência experimental e observacional de vírus da influenza equina H3N8 infectando seres humanos em diferentes partes do mundo no passado. Artigos publicados recentemente no Paquistão e na China destacaram a ameaça emergente e a capacidade dos vírus da influenza equina para uma epidemia em seres humanos no futuro. Neste artigo de revisão, resumimos os relatórios científicos relevantes publicados sobre a epidemiologia dos vírus da influenza equina e seu aspecto zoonótico. Além disso, vários desenvolvimentos recentes no início do século 21, incluindo a transmissão e estabelecimento de vírus da influenza equina em diferentes espécies animais, ou seja, camelos e cães, e presumida encefalopatia associada aos vírus da influenza em cavalos, documentaram a natureza imprevisível dos vírus da influenza equina. Em suma, vários relatórios destacaram a natureza imprevisível de H3N8 EIVs destacando a necessidade de vigilância contínua para H3N8 em equinos e humanos em contato com eles para novas mutações ameaçadoras.

Antibody responses after vaccination against equine influenza in Korea in 2016–2018 / 대한수의학회지

Equine influenza (EI) is the main cause of respiratory illness in equines across the globe and is caused by equine influenza A virus (EIV-A), which has impacted the equine industry internationally because of the marginal mortality and high morbidity. In the present study, the immune responses after equine influenza vaccination were evaluated in 4,144 horses in Korea using the hemagglutination inhibition (HI) assay. The equine influenza virus (EIV), A/equine/South Africa/4/03 (H3N8), was used as the antigen in the HI assay. The mean seropositive rates were 89.2% (97.4% in 2016, 77.6% in 2017, and 92.4% in 2018). This paper highlights the advances in understanding the effects of vaccines and control strategies for mitigating the emerging menace by EIV.

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

Abstract 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.

Equine influenza in Brazil / A influenza equina no Brasil

Equine influenza virus (EIV) (H3N8 and H7N7) is the causative agent of equine influenza, or equine flu. The H7N7 subtype has been considered to be extinct worldwide since 1980. Affected animals have respiratory symptoms that can be worsened by secondary bacterial respiratory infection, thereby leading to great economic losses in the horse-breeding industry. In Brazil, equine influenza outbreaks were first reported in 1963 and studies on hemagglutination antibodies against viral subtypes in Brazilian horses have been conducted since then. The objective of the present review was to present the history of the emergence of EIV around the world and in Brazil and the studies that have thus far been developed on EIV in Brazilian equines...

O vírus da influenza equina (EIV) (H3N8 e H7N7) é o agente causador da influenza equina, ou gripe equina. O subtipo viral H7N7 é considerado como mundialmente extinto desde 1980. Os animais afetados têm sintomas respiratórios característicos que podem ser agravados por uma infecção respiratória bacteriana secundária causando grandes prejuízos no ramo equestre. No Brasil, os surtos da EI têm sido relatados desde 1963 e desde então vem sendo efetuados estudos sobre a presença de anticorpos hemaglutinantes contra os subtipos virais nos equídeos brasileiros. O presente artigo tem o objetivo de apresentar um histórico sobre o surgimento do EIV no mundo e no Brasil destacando os estudos conduzidos no Brasil até o momento acerca da infecção pelo EIV nos equídeos brasileiros...