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.
Bell IG, Drury-Klein C.To analyse horse event and horse movement registration data collected between September 2007 and December 2008 during the outbreak of equine influenza in New South Wales, Australia. Results: A total of 9356 events were registered, involving 504,382 horses and 242,952 riders. Registered horse movements totalled 224,084, involving 349,327 horses (excluding mobs) travelling 34.4 million km with an average of 154 km per journey. The number of recorded events and movements were low while movement controls were most stringent, then increased from December 2007 as restrictions were eased, to peak in ...
Kirkland PD.During the 2007 equine influenza (EI) outbreak in Australia, diagnostic laboratories and the use of appropriate tests played a pivotal role in the response to the crisis. This role began with the detection of EI virus in New South Wales (NSW) on the evening of 24 August 2007 and culminated in providing the final 'proof of freedom' from EI in March 2008. The tests that were used during the EI response were able to provide results quickly, and with high sensitivity and specificity. This section of the supplement describes the roles and functions of the Australian laboratories; tests used and the...
Dhand NK, Sergeant ES.The aim of this preliminary study was to estimate the proportions of seropositive horses on infected premises (IPs) in order to assess the attack risk of the disease. Logistic regression analyses were conducted to evaluate the differences in attack risks between enterprise sizes and predefined spatial clusters/regions. The average attack risk experienced during the outbreak was 96.88% (median 100%), but it differed according to the size of the enterprise and other geographic and demographic conditions. The highest attack risks were observed in the Dubbo cluster/region and the lowest in the Nar...
Oakey J, Hawkesford T, Smith C, Hewitson G, Tolosa X, Wright L, Moody N, Rodwell B, Corney B, Waltisbuhl D.Describe the in-house validation of a previously reported influenza virus type A 5'Taq nuclease assay for detecting equine influenza virus A RNA in nasal swab material. Methods: The validation compares the 5'Taq nuclease assay with a gel-based reverse transcription nested polymerase chain reaction (PCR) previously reported by the Irish Equine Centre for detection of H3N8 and H7N7 equine influenza viruses. This test was chosen because it targets a different region of the viral genome to the real-time test, so it is not merely a repeat of the same test in a different format. Moreover, nested PCR...
Brown L, Townsend W, Waltisbuhl D.The unique challenges that laboratories in Queensland and New South Wales faced during the response to the 2007 equine influenza outbreak and how these were managed are described.
Crispe E, Finlaison DS, Hurt AC, Kirkland PD.During the equine influenza (EI) outbreak, respiratory disease was observed in dogs that were in close proximity to infected horses. Investigations were undertaken to exclude influenza virus infection. Of the 23 dogs that were seropositive in tests using the influenza A/Sydney/2007 virus as the test antigen, 10 showed clinical signs. EI virus appeared to be readily transmitted to dogs that were held in close proximity to infected horses, but there was no evidence of lateral transmission of the virus to other dogs that did not have contact with or were not held in close proximity to horses.
Croft MG, Fraser GC, Gaul WN.A Laboratory Information Management System (LIMS) was used to manage the laboratory data and support planning and field activities as part of the response to the equine influenza outbreak in Australia in 2007. The database structure of the LIMS and the system configurations that were made to best handle the laboratory implications of the disease response are discussed. The operational aspects of the LIMS and the related procedures used at the laboratory to process the increased sample throughput are reviewed, as is the interaction of the LIMS with other corporate systems used in the management...
Webster WR.In August 2007 equine influenza (EI) was diagnosed in Australia's horse population following the failure to contain infection in quarantine after the importation of one or more infected horses. The response had many unique features, and addressed financial, social, economic, human and animal health, trade and recovery issues. The outbreak and the associated control measures had a vast impact on individual horse owners, the horse industry and associated sectors in both infected and uninfected states.
Morton JM, Dups JN, Anthony ND, Dwyer JF.The risk of individuals becoming infected during an epidemic of infectious disease can vary as the disease progresses. Monitoring this risk may provide information about the dynamics of transmission. This study describes the epidemic curve for an epidemic of equine influenza (EI) in a closed population of horses predominantly immunologically naïve to EI at a 3-day event at Morgan Park in southern Queensland, Australia. The hazard function suggested that a subset of horses were at reduced risk of becoming infected. This highlights the importance, when modelling infectious disease in population...
Moloney B, Sergeant ES, Taragel C, Buckley P.Equine influenza (EI) was first diagnosed in the Australian horse population on 24 August 2007 at Centennial Park Equestrian Centre (CPEC) in Sydney, New South Wales (NSW), Australia. By then, the virus had already spread to many properties in NSW and southern Queensland. The outbreak in NSW affected approximately 6000 premises populated by approximately 47,000 horses. Analyses undertaken by the epidemiology section, a distinct unit within the planning section of the State Disease Control Headquarters, included the attack risk on affected properties, the level of under-reporting of affected pr...
Horká M, Kubíček O, Kubesová A, Rosenbergová K, Kubíčková Z, Šlais K.Influenza A is viral disease, which is a cause of yearly epidemics and, potentially, pandemics. The conventional techniques used today are equipment-demanding, time-consuming and laborious. Recently, we have confirmed that the capillary isoelectric focusing is a suitable fast alternative for the verifying of virus purity. In the wide pH gradient of pH range 2.0-7.5 the isoelectric points for subtypes of equine (H3N8) and swine (H1N2) influenza A viruses were determined approximately as 6.6 and 6.5, respectively. In this contribution we have verified these findings using different isolates of d...
Ji Y, Guo W, Zhao L, Li H, Lu G, Wang Z, Wang G, Liu C, Xiang W.An antigen-capture enzyme-linked immunosorbent assay (AC-ELISA) was developed for the detection of the equine influenza virus (EIV), employing monoclonal and polyclonal antibodies against the A/equine/Xingjiang/2007 (H3N8) nucleoprotein (NP). Immunoglobulin G antibodies were purified and used as capture or detector antibodies. The specificity of the optimized AC-ELISA was evaluated using EIV, equine herpesvirus 1 (EHV-1), equine herpesvirus 4 (EHV-4), equine arteritis virus (EAV) and Japanese encephalitis virus (JEV), resulting in only EIV specimens yielding a strong signal. A minimal concentr...
Virmani N, Bera BC, Shanumugasundaram K, Singh BK, Gulati BR, Singh RK, Vaid RK.India faced an epizootic of equine influenza in 2008-2009. The isolated viruses were typed as H3N8 and grouped with the clade 2 viruses of Florida sublineage on the basis of haemagglutinin (HA) gene sequence analysis. This report describes the genetic analysis and selection pressure of matrix (M) and non-structural 1 (NS1) genes of the Indian isolates. All isolates shared 98.41% and 99.54% homology with other clade 2 viruses of Asian origin for M1 and M2 amino acid (aa) sequences, respectively. There were 3 and 4 unique aa residue changes respectively in M1 and M2 proteins in all Asian isolate...
Elton D, Bryant N.Despite the availability of vaccines, equine influenza virus (EIV) continues to pose a threat to the racing industry. The virus spreads rapidly in unprotected populations and large scale outbreaks, such as those in South Africa in 2003 and Australia in 2007, can cost billions of pounds. Like other influenza viruses, EIV undergoes antigenic variation, enabling it to evade antibodies generated against previous infection or vaccination. The UK has an active surveillance programme to monitor antigenic drift and participates in an international collaboration with other countries in Europe, Japan an...
Firestone SM, Schemann KA, Toribio JA, Ward MP, Dhand NK.The 2007 epidemic of equine influenza in Australia provided an opportunity to investigate the effectiveness of on-farm biosecurity measures in preventing the spread of a novel pathogen in a largely naive population. We conducted a case-control study of 200 horse premises from highly affected regions of the state of New South Wales (NSW), to investigate risk factors for the spread of equine influenza onto horse premises, specifically, non-compliance with biosecurity measures recommended to horse owners by the relevant animal health authority, the NSW Department of Primary Industries. The study ...
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 ...
Murcia PR, Wood JL, Holmes EC.Equine influenza viruses (EIVs) of the H3N8 and H7N7 subtypes are the causative agents of an important disease of horses. While EIV H7N7 apparently is extinct, H3N8 viruses have circulated for more than 50 years. Like human influenza viruses, EIV H3N8 caused a transcontinental pandemic followed by further outbreaks and epidemics, even in populations with high vaccination coverage. Recently, EIV H3N8 jumped the species barrier to infect dogs. Despite its importance as an agent of infectious disease, the mechanisms that underpin the evolutionary and epidemiological dynamics of EIV are poorly und...
Abdel-Moneim AS, Shehab GM, Abu-Elsaad AA.Phylogenetic and evolutionary patterns of the six internal genes of an equine H5N1 influenza A virus isolated in Egypt on 2009 were analyzed using direct sequencing. All of the internal genes of the equine H5N1 strain showed a genetic pattern potentially related to Eurasian lineages. Variable dendrogram topologies revealed an absence of reassortment in the equine strain while confirming its close relatedness to other Egyptian H5N1 strains from human and avian species. The equine strain is characterized by a variety of amino acid substitutions in six internal proteins compared to the available ...
Gildea S, Arkins S, Walsh C, Cullinane A.Protection against equine influenza virus (EIV) relies largely on the production of circulating antibodies specific for the haemagglutinin (HA) glycoprotein. The objective of this study was to determine the antibody response of National Hunt horses in training to booster vaccination. The antibody response to the six equine influenza vaccines available in Ireland (three whole inactivated vaccines, two subunit vaccines and a canary pox recombinant vaccine), was monitored by single radial haemolysis (SRH) for six months post vaccination. There was no significant difference between antibody respon...
Gildea S, Arkins S, Cullinane A.Outbreaks of equine influenza (EI) in endemic populations continue to cause economic loss despite widespread vaccination. Objective: To identify the key management and environmental factors that determine the risk of horses contracting EI in an endemic country and to identify control strategies. Methods: Real time-polymerase chain reaction (RT-PCR), virus isolation and haemagglutination inhibition were carried out on nasopharyngeal swabs and clotted blood samples collected from horses and ponies showing signs of respiratory disease. On premises where a diagnosis of EI was confirmed, the attend...
Andersen SA, Petersen HH, Ersbøll AK, Falk-Rønne J, Jacobsen S.European and American guidelines for vaccination against tetanus and influenza in horses recommend annual and annual/semi-annual vaccinations, respectively, against the two pathogens. Too-frequent vaccination may, however, have adverse effects, among other things because an inflammatory response is elicited with subsequent alterations in homeostasis. The objective of the study was to compare the acute phase response (APR) in 10 horses following administration of two different types of vaccines, namely, an inactivated Immune Stimulating COMplex (ISCOM) vaccine and a live recombinant vector vacc...
Durando MM, Birks EK, Hussey SB, Lunn DP.Myocarditis is thought to occur secondary to equine influenza virus (EIV) infections in horses, but there is a lack of published evidence. Objective: We proposed that EIV challenge infection in ponies would cause myocardial damage, detectable by increases in plasma cardiac troponin I (cTnI) concentrations. Methods: Twenty-nine influenza-naïve yearling ponies: 23 were part of an influenza vaccine study (11 unvaccinated and 12 vaccinated), and were challenged with 10⁸ EID₅₀ EIV A/eq/Kentucky/91 6 months after vaccination. Six age-matched healthy and unvaccinated ponies concurrently housed...
Diaz-Mendez A, Viel L, Hewson J, Doig P, Carman S, Chambers T, Tiwari A, Dewey C.The objective of this project was to develop and implement an active surveillance program for the early and rapid detection of equine influenza viruses in Ontario. For this purpose, from October 2003 to October 2005, nasopharyngeal swabs and acute and convalescent serum samples were collected from 115 client-owned horses in 23 outbreaks of respiratory disease in Ontario. Sera were paired and tested for antibody to equine influenza 1 (AE1-H7N7), equine influenza 2 (AE2-H3N8), equine herpesvirus 1 and 4 (EHV1 and EHV4), and equine rhinitis A and B (ERAV and ERBV). Overall, the cause-specific mor...
Virmani N, Bera BC, Gulati BR, Karuppusamy S, Singh BK, Kumar Vaid R, Kumar S, Kumar R, Malik P, Khurana SK, Singh J, Manuja A, Dedar R, Gupta AK....Equine influenza is a contagious viral disease that affects all members of the family Equidae, i.e., horses, donkeys and mules. The authors describe the pattern of equine influenza outbreaks in a number of states of India from July 2008 to June 2009. The disease was first reported in June 2008 in Katra (Jammu and Kashmir) and spread to ten other states within a year. All outbreaks of equine influenza in the various states were confirmed by laboratory investigations (virus isolation and/or serological confirmation based on haemagglutination inhibition [HI] assays of paired samples) before decla...
Yamanaka T, Bannai H, Nemoto M, Tsujimura K, Kondo T, Matsumura T.In 2010, the World Organisation for Animal Health recommended the inclusion of a Florida sublineage clade2 strain of equine influenza virus (H3N8), which is represented by A/equine/Richmond/1/07 (Richmond07), in equine influenza vaccines. Here, we evaluate the antigenic differences between Japanese vaccine strains and Richmond07 by performing hemagglutination inhibition (HI) assays. Ferret antiserum raised to A/equine/La Plata/93 (La Plata93), which is a Japanese vaccine strain, reacted with Richmond07 at a similar titer to La Plata93. Moreover, two hundred racehorses exhibited similar geometr...
Zaleska M, Anusz K, Winnicka A, Kita J.Twelve horses, all of them 10 years old, were vaccinated intramuscularly on 0 and 28 days of the experiment with inactivated vaccine containing only antigens of A-equi-2/Miami/63. Another three unvaccinated horses, each at the age of 10 years, were the negative control group. One, ten-year-old horse was vaccinated with commercial inactivated vaccine containing both antigens of A-equi-2/Miami/63 as well as A-equi-1/Praha/56 as positive control. Three horses were challenged intranasally with homotypic strain of Miami/63, while six other were challenged with heterotypic strains--three with Suffol...
Yamanaka T, Tsujimura K, Kondo T, Matsumura T, Ishida H, Kiso M, Hidari KI, Suzuki T.Equine H3N8 influenza A viruses (EIVs) cause respiratory disease in horses and circulate among horses worldwide. In 2004, an outbreak of canine H3N8 influenza A virus (CIV) occurred among dogs in Florida and has spread among dogs in the United States (US). Genetic analyses revealed that this CIV is closely related to the recent EIVs. Although CIV-infected dogs could be the source of H3N8 influenza A virus for horses, it remains unclear whether the CIV circulating in the United States still maintains its infectivity and/or pathogenicity in horses. To address this, we investigated the infectivit...
Gildea S, Arkins S, Cullinane A.In Ireland, horses may be protected against equine influenza virus (EIV) as a result of natural exposure or vaccination. Current mandatory vaccination programmes are targeted at highly mobile horses. A correlation between antibody levels as measured by single radial haemolysis (SRH) and protective immunity against EIV has been established. Objective: The objective of this study was to determine the susceptibility of selected populations of horses by quantifying their antibodies to EIV. Methods: Blood samples were collected from Thoroughbred weanlings, yearlings, racehorses and broodmares, teas...
Morens DM, Taubenberger JK.To understand human influenza in a historical context of viral circulation in avian species, mammals, and in the environment. Methods: Historical review. Methods: Global events in a variety of circumstances over more than 3,000 years time. Methods: Comprehensive review of the historical literature including all major publications on pandemic and panzootic influenza. Methods: Influenza pandemics, panzootics, major epidemics and epizootics, and instances of interspecies transmission of influenza A. Results: Extensive documentation of human and animal influenza over many centuries suggests that i...
Oxburgh L, Hagström A.In this paper we describe the development of a nested RT-PCR assay for the rapid diagnosis and characterisation of influenza virus directly from clinical specimens. Viral RNA is extracted from nasal swabs by the guanidine thiocyanate extraction method, and subsequently reverse transcribed. The complementary DNA is then used as template in a nested PCR reaction. Primers designed for use in this assay are specific for three templates; (1) the nucleoprotein (NP) gene, (2) the haemagglutinin gene of the H7N7 equine influenza virus (A1), and (3) the haemagglutinin gene of the H3N8 equine influenza ...
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...
Fernandez EB, De Blas Giral I, Thiemann AK, Vázquez Bringas FJ.In the UK, there are thousands of donkeys being cared for by charities; however, little is known about the reasons for relinquishment or their previous health status, with even less information available in published literature. Such information could help to identify factors contributing to poor equine welfare and guide the development of appropriate educational resources. Objective: To describe the characteristics of the relinquished donkeys and to better understand the current preventative healthcare status of donkeys relinquished into The Donkey Sanctuary. Methods: Cross-sectional observat...
Dionísio L, Medeiros F, Pequito M, Faustino-Rocha AI.Influenza is an extremely contagious respiratory disease, which predominantly affects the upper respiratory tract. There are four types of influenza virus, and pigs and chickens are considered two key reservoirs of this virus. Equine influenza (EI) virus was first identified in horses in 1956, in Prague. The influenza A viruses responsible for EI are H7N7 and H3N8. Outbreaks of EI are characterized by their visible and rapid spread, and it has been possible to isolate and characterize H3N8 outbreaks in several countries. The clinical diagnosis of this disease is based on the clinical signs pre...
Back H, Weld J, Walsh C, Cullinane A.The aim of this study was to identify respiratory viruses circulating amongst elite racehorses in a training yard by serological testing of serial samples and to determine their impact on health status and ability to race. A six-month longitudinal study was conducted in 30 Thoroughbred racehorses (21 two-year-olds, five three-year-olds and four four-year-olds) during the Flat racing season. Sera were tested for the presence of antibodies against equine herpesvirus 1 and 4 (EHV-1 and EHV-4) and equine rhinitis viruses A and B (ERAV and ERBV) by complement fixation (CF) and equine arteritis viru...
Burrows R, Denyer M.The antigenic relationships between the haemagglutinins of five A/equine-1 viruses and between six A/equine-2 viruses were examined using post-infection ferret and immunized pony sera. Similar results were obtained with sera from both species for the A/equine-1 viruses and these confirmed minor antigenic differences between the prototype A/Prague 1/56 virus and viruses isolated in England in 1973 and 1977. Considerable antigenic differences were found between five of the A/equine-2 viruses, using ferret sera, but these differences were less evident using pony sera. The response of ponies to th...
Lee K, Pusterla N, Barnum SM, Lee DH, Martínez-López B.Equine influenza virus (EIV) is a major infectious pathogen causing significant respiratory signs in equids worldwide. Voluntary surveillances in the United States recently reported EIV detection in horses with respiratory signs even with adequate vaccine protocols and biosecurity programs and posed a concern about suboptimal effectiveness of EIV vaccine in the United States. This study aims to determine the genetic characteristics of 58 field EIV H3N8 strains in the United States from 2012 to 2017 using the phylogenetic analysis based on the haemagglutinin (HA) gene. Amino acid substitution a...
Hannant D, Mumford JA.Cytotoxic cell precursors and/or cytotoxic memory cells were demonstrated in the peripheral blood of ponies after aerosol infection with influenza A/equine/Newmarket/79 (H3N8). In order to reveal their cytotoxic potential, peripheral blood mononuclear cells required a secondary antigenic stimulation. In vitro induced cytotoxic cells showed activity against influenza infected target cells in a 3-4 h 51Cr-release assay. The reactivity of cytotoxic cells was markedly influenced by the conditions of the secondary induction culture. If high concentrations of exogenous crude equine IL-2 were used, v...
Jindra C, Hainisch EK, Rümmele A, Wolschek M, Muster T, Brandt S.Bovine papillomaviruses types 1 and 2 (BPV1, BPV2) commonly induce skin tumours termed sarcoids in horses and other equids. Sarcoids seriously compromise the health and welfare of affected individuals due to their propensity to resist treatment and reoccur in a more severe form. We have developed influenza (Flu) A and B virus vectors that harbour a truncated NS1 gene (iNS) assuring interferon induction and co-express shuffled BPV1 E6 and E7 antigens for sarcoid immunotherapy. In a safety trial involving 12 healthy horses, intradermal administration of iNSA/E6E7equ and iNSB/E6E7equ was well tol...
Pusterla N, James K, Mapes S, Bain F.Due to the inconsistent development of enteric signs associated with ECoV infection in adult horses, many practitioners collect nasal secretions rather than feces for the molecular diagnostic work-up of such horses. ECoV infection should be considered in horses presenting with acute onset of fever, especially when nasal discharge is absent as one of the cardinal clinical sign. A total of 277 adult horses with acute onset of fever were enrolled in this study. Feces were tested for ECoV and nasal secretions for common respiratory pathogens (equine herpesvirus (EHV)-1, EHV-4, equine influenza vir...
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...
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...
Spence KL, O'Sullivan TL, Poljak Z, Greer AL.Participation in equestrian shows provides opportunities for contact between horses, increasing the risk of disease introduction and spread within the population. The magnitude of a potential outbreak, and the impact of disease prevention and control strategies, can be estimated using simulation modeling. The objectives of this study were to (1) examine the potential spread of equine influenza in a network of horses associated with a 2-day equestrian show in Ontario, Canada; and (2) determine the effectiveness of several interventions during a simulated outbreak. A discrete-event, continuous-t...
Wilson A, Pinchbeck G, Dean R, McGowan C.Vaccination is integral to preventive healthcare. Despite numerous guidelines on equine vaccination, evidence of current vaccination practices is lacking. Objective: To describe current vaccination practices advised by vets treating horses in the United Kingdom (UK) and compare practices with manufacturer datasheets and current guidelines. Methods: Cross-sectional survey. Methods: An online questionnaire was distributed using email addresses acquired through professional registration listings and social media, targeting vets who treat horses in the UK. The questionnaire collected demographic d...
Schemann K, Firestone SM, Taylor MR, Toribio JA, Ward MP, Dhand NK.In August 2007, Australia experienced its first-ever outbreak of equine influenza, a highly infectious respiratory disease of horses. Although the outbreak spread over a large geographic area, it was eradicated within 5 months following a substantial disease control effort led by federal and state animal health authorities. Despite its timely control, this large-scale outbreak caused severe impacts on horse owners and industry participants. This study aimed to describe the perceptions of horse owners and managers, impacted by outbreak control measures, regarding the state government's animal h...
Heldens JG, Pouwels HG, van Loon AA.It has been recommended that modern equine influenza vaccines should contain an A/equi-1 strain and A/equi-2 strains of the American and European-like subtype. We describe here the efficacy of a modern updated inactivated equine influenza-herpesvirus combination vaccine against challenge with a recent American-like isolate of equine influenza (A/equine-2/Kentucky/95 (H3N8). The vaccine contains inactivated Influenza strains A-equine-1/Prague'56, A-equine-2/Newmarket-1/'93 (American lineage) and A-equine-2/ Newmarket-2/93 (Eurasian lineage) and inactivated EHV-1 strain RacH and EHV-4 strain V22...
Pavulraj S, Bergmann T, Trombetta CM, Marchi S, Montomoli E, Alami SSE, Ragni-Alunni R, Osterrieder N, Azab W.Equine influenza (EI) is a highly contagious acute respiratory disease of equines that is caused mainly by the H3N8 subtype of influenza A virus. Vaccinating horses against EI is the most effective strategy to prevent the infection. The current study aimed to compare the kinetics of EI-specific humoral- and cell-mediated immunity (CMI) in horses receiving either identical or mixed vaccinations. Two groups of horses were previously (six months prior) vaccinated with either Calvenza 03 EIV EHV (G1) or Fluvac Innovator (G2) vaccine. Subsequently, both groups received a booster single dose of Calv...
Virmani N, Bera BC, Shanumugasundaram K, Singh BK, Gulati BR, Singh RK, Vaid RK.India faced an epizootic of equine influenza in 2008-2009. The isolated viruses were typed as H3N8 and grouped with the clade 2 viruses of Florida sublineage on the basis of haemagglutinin (HA) gene sequence analysis. This report describes the genetic analysis and selection pressure of matrix (M) and non-structural 1 (NS1) genes of the Indian isolates. All isolates shared 98.41% and 99.54% homology with other clade 2 viruses of Asian origin for M1 and M2 amino acid (aa) sequences, respectively. There were 3 and 4 unique aa residue changes respectively in M1 and M2 proteins in all Asian isolate...
Soilemetzidou ES, de Bruin E, Eschke K, Azab W, Osterrieder N, Czirják GÁ, Buuveibaatar B, Kaczensky P, Koopmans M, Walzer C, Greenwood AD.The majority of influenza A virus strains are hosted in nature by avian species in the orders of Anseriformes and Charadriformes. A minority of strains have been able to cross species boundaries and establish themselves in novel non-avian hosts. Influenza viruses of horses, donkeys, and mules represent such successful events of avian to mammal influenza virus adaptation. Mongolia has over 3 million domestic horses and is home to two wild equids, the Asiatic wild ass or khulan (Equus hemionus hemionus), and Przewalski's horse (Equus ferus przewalskii). Domestic and wild equids are sympatric acr...
Chambers TM, Reedy SE.Serologic tests for equine influenza virus (EIV) antibodies are used for many purposes, including retrospective diagnosis, subtyping of virus isolates, antigenic comparison of different virus strains, and measurement of immune responses to EIV vaccines. The hemagglutination-inhibition (HI), single radial hemolysis (SRH), and serum micro-neutralization tests are the most widely used for these purposes and are described here. The presence of inhibitors of hemagglutination in equine serum complicates interpretation of HI assay results, and there are alternative protocols (receptor-destroying enzy...
Yamanaka T, Tsujimura K, Kondo T, Matsumura T.In this study, we evaluated whether five rapid antigen detection kits for human influenza could be used for the diagnosis of equine influenza (EI). Limiting dilution analyses showed that Directigen Flu A+B and ESPLINE INFLUENZA A&B-N had the highest sensitivities to equine-2 influenza viruses (EIVs) among the kits investigated. From the results of virus detection in nasal swabs taken from horses infected with EIV, these two kits could produce positive results in reasonable agreement with those obtained by virus isolation or RT-PCR, suggesting that these kits could be useful for rapid diagn...