Equine influenza is a highly contagious respiratory disease caused by influenza A viruses, specifically affecting horses. The disease is characterized by symptoms such as fever, coughing, nasal discharge, and lethargy. Transmission occurs primarily through aerosolized droplets and direct contact, leading to rapid spread among susceptible populations. Vaccination is a common preventive measure, though the virus's ability to mutate necessitates ongoing surveillance and vaccine updates. This page gathers peer-reviewed research studies and scholarly articles that explore the virology, epidemiology, clinical presentation, and management strategies of equine influenza, with a focus on its impact on equine health and welfare.
Olguin Perglione C, Golemba MD, Torres C, Barrandeguy M.Equine influenza virus (EIV) is considered the most important respiratory pathogen of horses as outbreaks of the disease lead to substantial economic losses. The H3N8 EIV has caused respiratory disease in horses across the world, including South American countries. Nucleotide and deduced amino acid sequences for the complete haemagglutinin gene of the H3N8 EIV detected in South America since 1963 were analyzed. Phylogenetic and Bayesian coalescent analyses were carried out to study the origin, the time of the most recent common ancestors (tMRCA), the demographic and the phylogeographic pattern...
Kupke A, Wenisch S, Failing K, Herden C.The olfactory epithelium (OE) is the only body site where neurons contact directly the environment and are therefore exposed to a broad variation of substances and insults. It can serve as portal of entry for neurotropic viruses which spread via the olfactory pathway to the central nervous system. For horses, it has been proposed and concluded mainly from rodent studies that different viruses, e.g., Borna disease virus, equine herpesvirus 1 (EHV-1), hendra virus, influenza virus, rabies virus, vesicular stomatitis virus can use this route. However, little is yet known about cytoarchitecture, p...
Takahashi T, Unuma S, Kawagishi S, Kurebayashi Y, Takano M, Yoshino H, Minami A, Yamanaka T, Otsubo T, Ikeda K, Suzuki T.Most equine influenza A viruses (IAVs) show strong binding to glycoconjugates containing N-glycolylneuraminic acid (Neu5Gc) as well as N-acetylneuraminic acid (Neu5Ac). Therefore, the progeny of equine IAV is thought to be released from the infected cell surface through removal of sialic acids by the viral sialidase. In the present study, equine IAV sialidases showed significantly lower substrate affinity than that of human IAV sialidases to artificial and natural Neu5Gc-conjugated substrates. The substrate specificity of equine IAV sialidases is in disagreement with their binding specificity ...
Meseko CA, Ehizibolo DO, Nwokike EC, Wungak YS.Equine influenza virus (EIV) is a major cause of acute respiratory diseases in horses in most parts of the world that results in severe economic losses. Information on the epidemiology of EIV in tropical Africa is scanty. An enzyme-linked immunosorbent assay (ELISA) was used to detect the presence of influenza A virus nucleoprotein (NP) in 284 horse sera in Kaduna State, Northern Nigeria. The ELISA-positive sera were further examined for hemagglutination inhibition (HI) antibodies to two strains each of H3N8 and H7N3 subtypes of influenza A virus. The results showed that antibodies against inf...
Barba M, Daly JM.Equine influenza virus remains a serious health and potential economic problem throughout most parts of the world, despite intensive vaccination programs in some horse populations. The influenza non-structural protein 1 (NS1) has multiple functions involved in the regulation of several cellular and viral processes during influenza infection. We review the strategies that NS1 uses to facilitate virus replication and inhibit antiviral responses in the host, including sequestering of double-stranded RNA, direct modulation of protein kinase R activity and inhibition of transcription and translatio...
Karamendin K, Kydyrmanov A, Sayatov M, Strochkov V, Sandybayev N, Sultankulova K.A retrospective phylogenetic characterization of the hemagglutinin, neuraminidase and nucleoprotein genes of equine influenza virus A/equine/Kirgizia/26/1974 (H7N7) which caused an outbreak in Kirgizia (a former Soviet Union republic, now Kyrgyzstan) in 1977 was conducted. It was defined that it was closely related to the strain London/1973 isolated in Europe and it shared a maximum nucleotide sequence identity at 99% with it. This Central Asian equine influenza virus isolate did not have any specific genetic signatures and can be considered as an epizootic strain of 1974 that spread in Europe...
Yamanaka T, Nemoto M, Bannai H, Tsujimura K, Kondo T, Matsumura T, Gildea S, Cullinane A.We previously reported that horse antiserum against the Japanese equine influenza vaccine virus, A/equine/La Plata/1993 (LP93) exhibited reduced cross-neutralization against some Florida sublineage Clade (Fc) 2 viruses, for example, A/equine/Carlow/2011 (CL11). As a result, Japanese vaccine manufacturers will replace LP93 with A/equine/Yokohama/aq13/2010 (Y10, Fc2). To assess the benefit of updating the vaccine, five horses vaccinated with inactivated Y10 vaccine and five vaccinated with inactivated LP93 were challenged by exposure to a nebulized aerosol of CL11. The durations of pyrexia (≥3...
Na W, Yeom M, Yuk H, Moon H, Kang B, Song D.This study provides information regarding vaccine research and the epidemiology of influenza virus in neglected hosts (horses and dogs). Equine influenza virus (EIV) causes a highly contagious disease in horses and other equids, and outbreaks have occurred worldwide. EIV has resulted in costly damage to the horse industry and has the ability of cross the host species barrier from horses to dogs. Canine influenza is a virus of equine or avian origin and infects companion animals that live in close contact with humans; this results in possible exposure to the seasonal epizootic influenza virus. ...
Lee J, Park JH, Min JY.The non-structural protein of influenza A virus (NS1A protein) is a multifunctional protein that antagonizes host antiviral responses and contributes to efficient viral replication during infection. However, most of its functions have been elucidated by generating recombinant viruses expressing mutated NS1 proteins that do not exist in nature. Recently, the novel H3N8 A/Equine/Kyonggi/SA1/2011 (KG11) influenza virus was isolated in Korea from horses showing respiratory disease symptoms. KG11 virus contains a naturally truncated NS gene segment with the truncation in the NS1A coding region, res...
Gildea S, Sanchez Higgins MJ, Johnson G, Walsh C, Cullinane A.There is a lack of information concerning concurrent administration of vaccines against equine influenza virus (EIV) and equine herpesvirus 1 and 4 (EHV-1/4). The primary objective of this study was to determine the impact of the concurrent use of EIV and EHV-1/4 vaccines in Thoroughbred racehorses on their humoral immune response to EIV. This study was carried out on a population of 30 horses using an inactivated whole-virus EIV vaccine and an inactivated EHV-1/4 vaccine. Horses were randomly allocated to vaccination group A or B. Horses in group A were vaccinated against EIV and EHV-1/4 2 we...
Fougerolle S, Legrand L, Garrett D, Birand I, Foursin M, D'Ablon X, Bayssat P, Newton RJ, Pronost S, Paillot R.Numerous equine influenza (EI) epizooties are reported worldwide. EI vaccination is the most efficient methods of prevention. However, not all horses develop protective immunity after immunisation, increasing the risk of infection and transmission. This field study aimed to understand the poor response to primary EI vaccination. The EI antibody response was measured in 174 Thoroughbred foals set in 3 stud farms (SF#1 to SF#3) over a 2years period. All foals were immunised with a commercial recombinant canarypox-based EI vaccine. Sera were tested by single radial haemolysis against the A/equine...
Paillot R, El-Hage CM.In 2007, Australia experienced the most extensive equine influenza outbreak observed in recent years. Extraordinary measures were rapidly implemented in order to control and prevent the spread of this highly contagious disease. The control strategy involved stringent movement restriction and disease surveillance, seconded by emergency post-outbreak vaccination strategies. Sixteen months after the first case and 12 months following the last reported case, Australia regained its equine influenza-free OIE status. This systematic review reports and summarises information relating to the implementa...
Lu G, He D, Wang Z, Ou S, Yuan R, Li S.An influenza virus polymerase reconstitution assay based on the human, dog, or chicken RNA polymerase I (PolI) promoter has been developed and widely used to study the polymerase activity of the influenza virus in corresponding cell types. Although it is an important member of the influenza virus family and has been known for sixty years, no studies have been performed to clone the horse PolI promoter or to study the polymerase activity of equine influenza virus (EIV) in horse cells. In our study, the horse RNA PolI promoter was cloned from fetal equine lung cells. Using the luciferase assay, ...
Kumar N, Bera BC, Greenbaum BD, Bhatia S, Sood R, Selvaraj P, Anand T, Tripathi BN, Virmani N.Equine influenza viruses (EIVs) of H3N8 subtype are culprits of severe acute respiratory infections in horses, and are still responsible for significant outbreaks worldwide. Adaptability of influenza viruses to a particular host is significantly influenced by their codon usage preference, due to an absolute dependence on the host cellular machinery for their replication. In the present study, we analyzed genome-wide codon usage patterns in 92 EIV strains, including both H3N8 and H7N7 subtypes by computing several codon usage indices and applying multivariate statistical methods. Relative synon...
Dominguez M, Münstermann S, Murray G, Timoney P.The 'high-health, high-performance' (HHP) horse concept has been developed by the World Organisation for Animal Health (OIE) together with the F6ddration Equestre Internationale and the International Federation of Horseracing Authorities. This concept is outlined in the OIE Terrestrial Animal Health Code (Chapter 4.16). It aims to address impediments to the international movement of competition horses through a harmonised, practically feasible, globally applicable framework based on simplified certification requirements for the temporary importation of HHP horses and for their return to their ...
Alves Beuttemmüller E, Woodward A, Rash A, Dos Santos Ferraz LE, Fernandes Alfieri A, Alfieri AA, Elton D.An extensive outbreak of equine influenza occurred across multiple countries in South America during 2012. The epidemic was first reported in Chile then spread to Brazil, Uruguay and Argentina, where both vaccinated and unvaccinated animals were affected. In Brazil, infections were widespread within 3months of the first reported cases. Affected horses included animals vaccinated with outdated vaccine antigens, but also with the OIE-recommended Florida clade 1 strain South Africa/4/03. Methods: Equine influenza virus strains from infected horses were isolated in eggs, then a representative stra...
Kinsley R, Scott SD, Daly JM.Serological assays provide an indirect route for the recognition of infectious agents via the detection of antibodies against the infectious agent of interest within serum. Serological assays for equine influenza A virus can be applied for different purposes: diagnosing infections; subtyping isolates; surveillance of circulating strains; and to evaluate the efficacy of vaccines before they reach the market. Haemagglutination inhibition (HI) and single radial haemolysis (SRH) assays are most commonly used in the equine field. This review outlines how both these assays together with virus neutra...
Yamanaka T, Nemoto M, Bannai H, Tsujimura K, Kondo T, Matsumura T, Gildea S, Cullinane A.Equine influenza (EI) is a highly contagious disease caused by viruses of the H3N8 subtype. The rapid diagnosis of EI is essential to reduce the disease spread. Many rapid antigen detection (RAD) tests for diagnosing human influenza are available, but their ability to diagnose EI has not been systematically evaluated. Objective: The aim of this study was to compare the performance of 22 RAD tests in the diagnosis of EI. Methods: The 22 RAD tests were performed on fivefold serial dilutions of EI virus to determine their detection limits. The four most sensitive RAD tests (ImmunoAce Flu, BD Flu ...
West Nile virus in Europe and the USA. Evidence that the spread of vesicular stomatitis in the USA is beginning to slow. Summary of UK surveillance testing, July to September 2015 These are among matters discussed in the most recent quarterly equine disease surveillance report, prepared by Defra, the Animal Health Trust and the British Equine Veterinary Association.
Aeschbacher S, Santschi E, Gerber V, Stalder HP, Zanoni RG.Equine influenza is a highly contagious respiratory disease in horses caused by influenza A viruses. In this work a real-time RT-PCR for fast and sensitive diagnosis of equine influenza viruses (EIV) targeting a highly conserved region of the matrix gene was developed. In addition two RT-PCR methods for the amplification of large parts of the matrix- and HA gene were adapted for molecular-epidemiological characterization of viruses. The primers of the real-time RT-PCR had homologies of 99.4% to EIV- and 97.7% to all influenza A viral sequences, whereas the minor groove binder (MGB) probe showe...
Back H, Berndtsson LT, Gröndahl G, Ståhl K, Pringle J, Zohari S.Equine Influenza Virus (EIV) is a major cause of respiratory disease in horses and the virus constantly undergoes antigenic drift. Here we characterize and describe the HA1 and the NA genes of H3N8 within samples obtained from outbreaks in Sweden during November-December 2011. Both clade 1 and clade 2 viruses of the Florida sublineage were identified. The index case of clade 2 was transported to Sweden from Spain through the Netherlands, whereas the clade 1 had its origin from a Swedish stud farm. The clade 1 virus was efficiently spread between training yards by unvaccinated young horses, but...
Lee E, Kim EJ, Shin YK, Song JY.The avian influenza A virus causes respiratory infections in animal species. It can undergo genomic recombination with newly obtained genetic material through an interspecies transmission. However, the process is an unpredictable event, making it difficult to predict the emergence of a new pandemic virus and distinguish its origin, especially when the virus is the result of multiple infections. Therefore, identifying a novel influenza is entirely dependent on sequencing its whole genome. Occasionally, however, it can be time-consuming, costly, and labor-intensive when sequencing many influenza...
Pavulraj S, Bera BC, Joshi A, Anand T, Virmani M, Vaid RK, Shanmugasundaram K, Gulati BR, Rajukumar K, Singh R, Misri J, Singh RK, Tripathi BN....Equine influenza viruses (EIV)-H3N8 continue to circulate in equine population throughout the world. They evolve by the process of antigenic drift that leads to substantial change in the antigenicity of the virus, thereby necessitating substitution of virus strain in the vaccines. This requires frequent testing of the new vaccines in the in vivo system; however, lack of an appropriate laboratory animal challenge model for testing protective efficacy of equine influenza vaccine candidates hinders the screening of new vaccines and other therapeutic approaches. In the present investigation, BALB/...
Kwasnik M, Gora IM, Rola J, Zmudzinski JF, Rozek W.The phylogenetic analysis of influenza virus is based mainly on the variable hemagglutinin or neuraminidase genes. However, some discrete evolutionary trends might be revealed when more conservative genes are considered. We compared all available in GenBank database full length NS sequences of equine influenza virus including Polish isolates. Four nucleotides at positions A202, A237, T672 and A714 and three amino acids at positions H59, K71 and S216 which are also present in A/eq/Pulawy/2006 and A/eq/Pulawy/2008 may be discriminating for the Florida sublineage. Threonine at position 83 seems t...
Perglione CO, Gildea S, Rimondi A, Miño S, Vissani A, Carossino M, Cullinane A, Barrandeguy M.In 2012, equine influenza (EI) virus was confirmed as the cause of outbreaks of respiratory disease in horses throughout South America. In Uruguay and Argentina, hundreds of vaccinated thoroughbred horses in training and racing facilities were clinically affected. Objective: To characterise the EI viruses detected during the outbreak in Uruguay and Argentina. Methods: Virus was detected in nasopharyngeal swabs by a pan-reactive influenza type A real-time RT-PCR. The nucleotide sequence of the HA1 gene was determined and analysed phylogenetically using mega 5 software. Amino acid sequences alig...
BMC research notesSeptember 24, 2015
Volume 8 471 doi: 10.1186/s13104-015-1441-0
Boukharta M, Azlmat S, Elharrak M, Ennaji MM.Three equine influenza viruses, A/equine/Nador/1/1997(H3N8), A/equine/Essaouira/2/2004(H3N8), and A/equine/Essaouira/3/2004(H3N8), were isolated from different Equidae during local respiratory disease outbreaks in Morocco in 1997 and 2004. Their non-structural (NS) genes were amplified and sequenced. Results: The results show high homology of NS nucleotide sequences of A/equine/Nador/1/1997 with European strains (i.e., A/equine/newmarket/2/93 and A/equine/Grobois/1/1998) and clustered into the European lineage. However, NS gene of A/equine/Essaouira/2/2004(H3N8) and A/equine/Essaouira/3/2004(H...
Doud MB, Ashenberg O, Bloom JD.Evolution drives changes in a protein's sequence over time. The extent to which these changes in sequence lead to shifts in the underlying preference for each amino acid at each site is an important question with implications for comparative sequence-analysis methods, such as molecular phylogenetics. To quantify the extent that site-specific amino acid preferences shift during evolution, we performed deep mutational scanning on two homologs of human influenza nucleoprotein with 94% amino acid identity. We found that only a modest fraction of sites exhibited shifts in amino acid preferences tha...
Back H, Penell J, Pringle J, Isaksson M, Ronéus N, Treiberg Berndtsson L, Ståhl K.While clinical respiratory disease is considered a main cause of poor performance in horses, the role of subclinical respiratory virus infections is less clear and needs further investigation. Objective: In this descriptive longitudinal study the relationship of markers of subclinical respiratory viral activity to occurrence of poor performance in racing Standardbred trotters was investigated. Methods: 66 elite Standardbred trotters were followed for 13 months by nasal swabs analysed with qPCR for equine influenza virus, equine arteritis virus, equine rhinitis B virus (ERBV), equine herpesvi...
Kim EJ, Kim BH, Yang S, Choi EJ, Shin YJ, Song JY, Shin YK.In this study, antibody responses after equine influenza vaccination were investigated among 1,098 horses in Korea using the hemagglutination inhibition (HI) assay. The equine influenza viruses, A/equine/South Africa/4/03 (H3N8) and A/equine/Wildeshausen/1/08 (H3N8), were used as antigens in the HI assay. The mean seropositive rates were 91.7% (geometric mean antibody levels (GMT), 56.8) and 93.6% (GMT, 105.2) for A/equine/South Africa/4/03 and A/equine/Wildeshausen/1/08, respectively. Yearlings and two-year-olds in training exhibited lower positive rates (68.1% (GMT, 14) and 61.7% (GMT, 11.9)...
Feng KH, Gonzalez G, Deng L, Yu H, Tse VL, Huang L, Huang K, Wasik BR, Zhou B, Wentworth DE, Holmes EC, Chen X, Varki A, Murcia PR, Parrish CR.The A/H3N8 canine influenza virus (CIV) emerged from A/H3N8 equine influenza virus (EIV) around the year 2000 through the transfer of a single virus from horses to dogs. We defined and compared the biological properties of EIV and CIV by examining their genetic variation, infection, and growth in different cell cultures, receptor specificity, hemagglutinin (HA) cleavage, and infection and growth in horse and dog tracheal explant cultures. Comparison of sequences of viruses from horses and dogs revealed mutations that may be linked to host adaptation and tropism. We prepared infectious clones o...
Gershwin LJ, Netherwood KA, Norris MS, Behrens NE, Shao MX.Vaccination of horses is performed annually or semi-annually with multiple viral antigens, either in a combination vaccine or as separate injections. While this practice undoubtedly prevents infection from such diseases as rabies, equine influenza, West Nile virus, and equine herpes virus, the procedure is not without repercussions. Hypersensitivity reactions, including fatal anaphylactic shock, after vaccination, although uncommon, have increased in incidence in recent years. Studies reported herein document the development of IgE antibodies against non-target antigen components of equine vir...
Pagamjav O, Kobayashi K, Murakami H, Tabata Y, Miura Y, Boldbaatar B, Sentsui H.Three hundred sera were collected from horses in various parts of Mongolia in 2007 and seroepidemiological surveys for several equine viruses performed on them. Equid herpesvirus 1 and equine rhinitis A virus were prevalent, and equine arteritis virus and equid herpesvirus 3 were detected over a wide area though their rates of antibody-positivity were not high. Equine infectious anemia was distributed locally. The rates of horses antibody-positive for Japanese encephalitis virus and equine influenza virus were low, but these were detected. Bovine coronavirus antibodies were detected at a high ...
Crouch CF, Daly J, Hannant D, Wilkins J, Francis MJ.Protective responses generated by vaccination with an immuno-stimulating complex (ISCOM)-based vaccine for equine influenza (EQUIP F), containing a new 'American lineage' H3N8 virus, were studied. Seven ponies in the vaccine group received two intramuscular injections of EQUIP F given 6 weeks apart. Aerosol challenge with an A/eq/Newmarket/1/93 reference strain 4 weeks after booster vaccination resulted in clinical signs of infection and viral shedding in 7 influenza-naive control animals whereas the vaccinated ponies were significantly protected from both clinical signs and virus excretion. I...
Crouch CF, Daly J, Henley W, Hannant D, Wilkins J, Francis MJ.In horses, natural infection confers long lasting protective immunity characterised by mucosal IgA and humoral IgGa and IgGb responses. In order to investigate the potential of locally administered vaccine to induce a protective IgA response, responses generated by vaccination with an immunostimulating complex (ISCOM)-based vaccine for equine influenza (EQUIP F) containing A/eq/Newmarket/77 (H7N7), A/eq/Borlänge/91 (H3N8) and A/eq/Kentucky/98 (H3N8) using a systemic prime/mucosal boost strategy were studied. Seven ponies in the vaccine group received EQUIP F vaccine intranasally 6 weeks after...
Adeyefa CA, Quayle K, McCauley JW.We describe a rapid method for genetic characterisation of influenza virus genes using reverse transcription and amplification by polymerase chain reaction (RT/PCR) of all virus segments simultaneously (multiplex RT/PCR) using primers based on the conserved terminal sequences. The product has been shown to be suitable for determination of partial nucleotide sequences which can be used to search nucleotide sequence databases and rapidly map the genetic origin of each segment. We illustrate the use of the method by analysing genetic reassortment in H7N7 equine influenza viruses.
Whitlock F, Grewar J, Newton R.During 2019, an epidemic of equine influenza (EI) occurred in Europe. Objective: To describe the epidemiology of the 2019 EI epidemic within Great Britain (GB). Methods: Retrospective descriptive study of laboratory confirmed EI cases. Methods: Epidemiological data were obtained from veterinary surgeons referring samples for EI virus testing. Where available, data on confirmed cases and their wider resident population on EI-infected premises were collated and described. On a national level, spatial and temporal representations, consisting of choropleth maps and epidemic curves, described the s...
Chambers TM.Equine influenza virus (EIV) is a common respiratory pathogen of horses and other equids in most parts of the world. EIV are Type A influenza viruses and two subtypes are known: H3N8 and H7N7. Both are believed to have evolved from avian influenza virus ancestors. The H3N8 subtype circulates widely, but the H7N7 subtype is thought to be extinct. The clinical disease in horses, caused by either subtype, is an upper respiratory infection of varying severity depending upon the immune status of the individual animal. It is not normally life-threatening in itself except in very young foals; however...
Park AW, Wood JL, Newton JR, Daly J, Mumford JA, Grenfell BT.A stochastic model of equine influenza (EI) is constructed to assess the risk of an outbreak in a Thoroughbred population at a typical flat race training yard. The model is parameterised using data from equine challenge experiments conducted by the Animal Health Trust (relating to the latent and infectious period of animals) and also published data on previous epidemics (to estimate the transmission rate for equine influenza). Using 89 ponies, an empirical relationship between pre-challenge antibody and the probability of becoming infectious is established using logistic regression. Changes in...
Ozaki H, Sugiura T, Sugita S, Imagawa H, Kida H.Antibodies to the nonstructural protein (NS1) of A/equine/Miami/1/63 (H3N8) influenza virus were detected exclusively in the sera of mice experimentally infected with A/Aichi/2/68 (H3N2) and horses infected with A/equine/Kentucky/1/81 (H3N8) or A/equine/La Plata/1/93 (H3N8), but not in those of the animals immunized with the inactivated viruses, by enzyme-linked immunosorbent assay (ELISA) using a recombinant NS1 as antigen. The results indicate that the present method is useful for serological diagnosis to distinguish horses infected with equine H3 influenza viruses from those immunized with ...
Lai AC, Rogers KM, Glaser A, Tudor L, Chambers T.Phylogenetic and antigenic analyses indicate that recent circulating equine-2 influenza viruses in the United States have been alternating between two genetic and antigenic distinct lineages since 1996. The evolution rates for these two lineages, the Kentucky and the Florida lineage, are very similar. For the earlier isolates in the Kentucky lineage, there are multiple and sequential nonsynonymous substitutions at antigenic sites B and D. However, there are no changes at any of these antigenic sites for KY98 and OK00. In the Florida lineage, except for NY99 with one amino acid substitution at ...
Paillot R, Prowse L.The humoral immune response induced by ISCOM-matrix (Immuno Stimulating COMplex-Matrix)-adjuvanted equine influenza virus (EIV) vaccine is well documented in horses. ISCOM-matrix adjuvanted vaccines against human influenza are strong inducers of cell-mediated immunity (CMI), including T cell proliferation and virus-specific cytotoxic T cell. In the horse, the CMI response to equine influenza vaccination is less well characterised. An ISCOM-based vaccine has been shown to induce interferon gamma (IFN-γ) synthesis, a CMI marker, in the horse, but this has not been shown for the ISCOM-matrix vac...
Firestone SM, Lewis FI, Schemann K, Ward MP, Toribio JA, Taylor MR, Dhand NK.Australia experienced its first ever outbreak of equine influenza in August 2007. Horses on 9359 premises were infected over a period of 5 months before the disease was successfully eradicated through the combination of horse movement controls, on-farm biosecurity and vaccination. In a previous premises-level case-control study of the 2007 equine influenza outbreak in Australia, the protective effect of several variables representing on-farm biosecurity practices were identified. Separately, factors associated with horse managers' perceptions of the effectiveness of biosecurity measures have b...
Newton JR, Verheyen K, Wood JL, Yates PJ, Mumford JA.In 1998, equine influenza was diagnosed by serology and nucleoprotein enzyme-linked immunosorbent assay as the cause of acute respiratory disease in vaccinated and unvaccinated horses in the UK. The signs were generally milder in vaccinated horses and completely susceptible animals showed the most severe signs, including pyrexia, inappetence, coughing, mucopurulent nasal discharge and secondary bacterial pneumonia. In a detailed investigation of an outbreak among 52 vaccinated thoroughbreds in a flat racing yard, more than 60 per cent of the horses seroconverted on the evidence of paired serum...
Laabassi F, Lecouturier F, Amelot G, Gaudaire D, Mamache B, Laugier C, Legrand L, Zientara S, Hans A.An outbreak of equine influenza (EI) was reported in Algeria between May and July, 2011. The outbreak started in Tiaret, in west province of Algeria, and spread to the other parts of the country affecting almost 900 horses in many provinces. The population studied was composed of 325 horses from different groups of age. Clinical sign expression was age dependent. Indeed, a morbidity rate of 14.9% was observed in horses under 15 months old and a rate of 4.95% in horses over 8 years old. Interestingly, the morbidity rate raised sharply to reach 100% in horses aged between 18 months and 7 yea...
Karamendin K, Kydyrmanov A, Kasymbekov Y, Khan E, Daulbayeva K, Asanova S, Zhumatov K, Seidalina A, Sayatov M, Fereidouni SR.Equine influenza (EI) continues to be an important respiratory pathogen of horses worldwide. Since 2007 several outbreaks of EI have occurred in Central Asian countries, including Kazakhstan, western Mongolia, India and western China. Phylogenetic analysis showed that two H3N8 equine influenza virus (EIV) isolates from Kazakhstan, A/equine/Almaty/26/2007 and A/equine/South Kazakhstan/236/12, were related to Florida sublineage 2, with high similarity to EIVs circulating in the same period in neighbouring countries. New outbreaks of EI during 2011 and 2012 in Kazakhstan and other Central Asian c...
Na W, Yeom M, Yuk H, Moon H, Kang B, Song D.This study provides information regarding vaccine research and the epidemiology of influenza virus in neglected hosts (horses and dogs). Equine influenza virus (EIV) causes a highly contagious disease in horses and other equids, and outbreaks have occurred worldwide. EIV has resulted in costly damage to the horse industry and has the ability of cross the host species barrier from horses to dogs. Canine influenza is a virus of equine or avian origin and infects companion animals that live in close contact with humans; this results in possible exposure to the seasonal epizootic influenza virus. ...
Spence KL, O'Sullivan TL, Poljak Z, Greer AL.Identifying the contact structure within a population of horses attending a competition is an important element towards understanding the potential for the spread of equine pathogens as the horses subsequently travel from location to location. However, there is limited information in Ontario, Canada to quantify contact patterns of horses. The objective of this study was to describe the network of potential contacts associated with an equestrian show to determine how this network structure may influence potential disease transmission. Results: This was a descriptive study of horses attending an...
Mumford EL, Traub-Dargatz JL, Salman MD, Collins JK, Getzy DM, Carman J.To develop a system to monitor and detect acute infections of the upper respiratory tract (i.e., nares, nasopharynx, and pharynx) in horses and to assess the association among specific viral infections, risk factors, and clinical signs of disease. Methods: Prospective study. Methods: 151 horses with clinical signs of acute infectious upper respiratory tract disease (IURD) from 56 premises in Colorado. Methods: Health management data, blood samples, and nasal or nasopharyngeal swab samples were obtained for 151 horses with clinical signs of acute IURD. Of these horses, 112 had an additional blo...
Paillot R, Marcillaud Pitel C, D'Ablon X, Pronost S.To date, vaccination is one of the most efficient methods of prevention against equine infectious diseases. The vaccinology session, which was organised during the annual meeting of the French Equine Veterinarians Association (AVEF) at Reims (France) in 2016, aimed to approach three subjects of importance for the equine industry. Vaccination against three major equine diseases were used as examples: equine influenza (equine influenza virus), rhinopneumonitis (equine herpes virus 1/4), and tetanus ( neuro-toxin). (1) Emergency vaccination: while it has been very successful to reduce the impact ...
Morley PS, Townsend HG, Bogdan JR, Haines DM.To identify risk factors associated with respiratory tract disease in horses during 3 epidemics caused by influenza virus infections. Methods: Cross-sectional and prospective longitudinal observational studies. Methods: 1,163 horses stabled at a Thoroughbred racetrack. Methods: Investigations were conducted during a 3-year period. An epidemic of respiratory tract disease caused by influenza virus infections was identified in each year. Routine observations and physical examinations were used to classify horses' disease status. Data were analyzed to identify factors associated with development ...
Yamanaka T, Nemoto M, Bannai H, Tsujimura K, Kondo T, Matsumura T, Muranaka M, Ueno T, Kinoshita Y, Niwa H, Hidari KI, Suzuki T.Since equine influenza A virus (H3N8) was transmitted to dogs in the United States in 2004, the causative virus, which is called canine influenza A virus (CIV), has become widespread in dogs. To date, it has remained unclear whether or not CIV-infected dogs could transmit CIV to horses. To address this, we tested whether or not close contact between horses and dogs experimentally infected with CIV would result in its interspecies transmission. Methods: Three pairs of animals consisting of a dog inoculated with CIV (10(8.3) egg infectious dose 50/dog) and a healthy horse were kept together in i...
Birch-Machin I, Rowan A, Pick J, Mumford J, Binns M.The nucleotide sequence of the nonstructural protein NS1 of the influenza virus A/equine 2/Suffolk/89 was determined and found to be 97% identical to that of A/equine 2/Miami/63. A similar level of identity was shown for the deduced NS1 amino acid sequence. The NS1 gene was expressed, in its entirety and in part, as fusion proteins with glutathione S-transferase using the pGEX-3X expression vector. Antibodies to NS1 protein were detected in serum samples from ponies experimentally infected with influenza virus, but not in animals vaccinated with whole inactivated virus or in unprimed control a...
Glass K, Wood JL, Mumford JA, Jesset D, Grenfell BT.This paper demonstrates that a simple stochastic model can capture the features of an epidemic of equine influenza in unvaccinated horses. When the model is modified to consider vaccinated horses, we find that vaccination dramatically reduces the incidence and size of epidemics. Although occasional larger outbreaks can still occur, these are exceptional. We then look at the effects of vaccination on a yard of horses, and in particular at the relationship between pre-challenge antibody level and quantity of virus shed when challenged with the virus. While on average, a high antibody level impli...
Yamanaka T, Cullinane A, Gildea S, Bannai H, Nemoto M, Tsujimura K, Kondo T, Matsumura T.The protection induced by an equine influenza (EI) vaccine strain depends on its antigenic relatedness to the challenge virus. Although the World Organisation for Animal Health (OIE) recommend that both Florida sublineage clade 1 (Fc1) and clade 2 (Fc2) viruses should be included in EI vaccines, Japanese EI vaccines have not, thus far, been updated to include a Fc2 virus. Objective: To evaluate the efficacy of antibodies raised against Japanese EI vaccine strains in the neutralisation of recent Fc2 viruses. Methods: Antigenic analysis. Methods: Virus neutralisation tests were performed using a...
Mumford EL, Traub-Dargatz JL, Carman J, Callan RJ, Collins JK, Goltz KL, Romm SR, Tarr SF, Salman MD.Horses vaccinated against common agents of infectious upper respiratory disease (IURD) may not have detectable serum antibody and may not be protected from clinical disease. Objective: The objectives of this study were to 1) investigate the serological response of horses to vaccination against influenza virus (H3N8 and H7N7) and equine herpesviruses (EHV) in a field setting and 2) evaluate associations among vaccination status, serum antibody concentrations, and occurrences of IURD in monitored horses. Methods: In this study, horses on 6 Colorado premises were vaccinated parenterally against i...
Burrows R, Denyer M, Goodridge D, Hamilton F.Experimental ponies developed signs of disease four days after the intranasal instillation of A/England 1/79 equine influenza virus and virus was recovered from the nasopharynx from the second to the ninth day. No significant antigenic difference was found between the virus and the prototype A/Miami 1/63 virus, using post infection ferret and chicken sera and post vaccination pony sera. No antigenic differences were found between four viruses isolated between January and July 1979, although some differences were found in their ability to detect haemagglutination inhibiting antibody in convales...
Paillot R, Prowse L, Donald C, Medcalf E, Montesso F, Bryant N, Watson J, Jeggo M, Elton D, Newton R, Trail P, Barnes H.An outbreak of H3N8 Equine Influenza virus (EIV) that occurred in vaccinated horses in Japan was caused by a genetically divergent EIV isolate of the Florida clade 1 sub-lineage. This virus subsequently entered Australia where it infected thousands of immunologically naïve horses. The objective of this study was to evaluate the ability of a non-updated whole inactivated equine influenza (EI) vaccine to protect if used in the face of an outbreak induced by a virus similar to the ones circulating in Japan and Australia in 2007. Seven naïve Welsh mountain ponies were immunised twice with the co...
