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.
Tumova B, Easterday BC.This study demonstrates relationships in envelope antigens of 4 human influenza A2 strains isolated during the period 1957-68 (including A2/Hong Kong/68), 2 strains of A/Equi-2/63 and 7 avian influenza viruses isolated in Europe, North America, and the Ukraine in the years 1960-67.Antigenic relationships among the strains were determined on the basis of haemagglutination-inhibition, virus-neutralization, strain-specific complement-fixation, and neuraminidase-inhibition tests.North American avian influenza strains, Turkey/California/64, Turkey/Massachusetts/65, Turkey/Wisconsin/66, Turkey/Ontar...
Singh G.A/eq-1 and A/eq-2 influenza viruses were isolated simultaneously from an epidemic of equine influenza in north India. Evidently, both types of equine influenza viruses circulated in the equine population at the same time.
Sugita S, Oki H, Hasegawa T, Ishida N.Estimation formulas for the morbidity of horses infected with equine influenza virus by linear regression, logistic regression and probit transformation were developed, using data from the outbreak at the Sha Tin Racing Track in Hong Kong in 1992. Using these formulas, we estimated the equine influenza virus morbidity rates at training centers belonging to the Japan Racing Association (JRA) in October 1997 and in October 1998. In 1998 JRA started a new vaccination program, and every horse must now be vaccinated twice per year. At that time, the vaccine included two US lineage virus strains, th...
Paskin R.The equine influenza outbreak detected in August 2007 in New South Wales and Queensland did not enter Victoria, which was, however, considered at risk because of its sizable border with New South Wales. Accordingly, Victoria implemented a response plan to prevent disease entry and enable early detection of any disease. Horse movement restrictions, surveillance strategies and public awareness formed a large part of this response.
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.
Nemoto M, Okita N, Kitahata M, Bannai H, Tsujimura K, Kinoshita Y, Kambayashi Y, Cullinane A, Yamanaka T, Ohta M.A rapid and sensitive diagnostic method is needed to help prevent the spread of equine influenza virus. The cobas Influenza A/B & RSV test for the cobas Liat system (Roche Diagnostics) is based on real-time reverse transcription polymerase chain reaction and is designed to broadly detect influenza A virus RNA within 20 minutes. It detected a broad range of equine influenza virus strains, and detected equine influenza virus RNA from nasal swabs of infected horses at the same level as real-time reverse transcription polymerase chain reaction, although it returned some invalid results (7.7%)...
Verberne LR, Mirck MH.A comparative study of the literature of the past ten years showed that vaccination of horses and ponies against influenza is best done using adjuvant-containing vaccines. Comparable results may probably be obtained by twice inoculating an aquenous vaccine. There are no drawbacks to the use of aluminium-hydroxide as an adjuvant when mineral oil is used as an adjuvant, the first and second vaccinations do not present any problems.
Benmansour A, Benelmouffok A, Bouguermouh A.During an epizootic of equine acute respiratory disease in Algeria, a strain of equine influenza virus was isolated. Sera examination by hemagglutinin inhibition test and complement fixation test confirmed the etiology of the disease. The first and second outbreak of the disease remained localised. The third outbreak spread within few months to all parts of the country. Horses vaccinated with a commercial equine influenza vaccine remained healthy.
Britton AL, Major DA, Perry GH, Read AJ.The interaction and stabling of horses at equine events may have a substantial impact on the spread of a zoonotic disease. This study aimed to investigate the spread of equine influenza (EI) at an equestrian event at the start of the Australian outbreak. Around one-third of the competing horses were stabled overnight at the event and, of these, 70% developed symptoms of EI within 7 days. The index case was never positively identified, but stabling position and disease onset provided clues to its potential identity.
Stellmann C, Petermann HG.After vaccination of chickens, rabbits, foals and horses, HI and SN antibody dose response curves were compared for A/Equi 1/Prague and A/Equi 2/Paris strains.
The two curves are parallel for a given strain and the relationship of HI and SN titres is constant, whatever the animal species.
The distribution of HI and SN titres varies for the two strains.
This variation, which is independent of animal species, may be related to the number of sites necessary for the antigenic-antibody response in vitro.
It is suggested that the testing of equine influenza vaccine be carried out in the ...
Khan Y, Kassymbekov Y, Suleimenova S, Karamendin K, Sabyrzhan T, Nuralibekov S, Daulbayeva K, Abishov A, Akhmetzhanova M, Akhmetsadykov N, Batanova Z....An influenza virus strain, A/equine/Almaty/268/2020, was isolated from horses in southeast Kazakhstan in 2020. Here, we present the nearly complete genome sequence of this epidemic strain. This study was aimed at obtaining the complete genome sequence of the isolate.
An outbreak of equine viral arteritis in the American state of Kentucky led to a temporary ban being imposed by France, Ireland and the UK on the importation of horses from the USA during 1984. Sporadic cases of influenza caused by the type 2 strain of the virus were confirmed in France throughout the year and cases of strangles in thoroughbred mares and foals were reported from all three countries. No cases of contagious equine metritis were confirmed among the thoroughbred breeding population, although a number of outbreaks of the abortion form of rhinopneumonitis occurred. A small number of...
Drury M.Participants in the 1- and 2-day Tamworth Dressage Club (TDC) annual dressage championships arrived in Moonbi, New South Wales (NSW) as reports of the equine influenza outbreak surfaced on 25 August 2007. Three horses who had attended a competition in Maitland the weekend before had been showing flu-like symptoms and the next day the site was declared a suspect premise. On 27 August, infection was confirmed and the site was placed in total quarantine. Although most participants had travelled long distances to compete and did not have provisions for them or their horses, the quarantine was not ...
Denyer MS, Crowther JR.Antigenic differences within equine-1 and equine-2 isolates of influenza were studied by haemagglutination inhibition tests, indirect ELISA and competition ELISA, using the same antisera. Better differentiation was obtained with the competition ELISA than with the other two tests. All three methods produced similar relationships within the equine-1 isolates but differed in their ability to differentiate the equine-2 isolates where the competition ELISA was superior and produced epidemiologically sensible results. In all three tests, post-infection ferret and horse sera were more useful in disc...
Khan A, Mushtaq MH, Ahmad MUD, Nazir J, Fatima Z, Khan A, Farooqi SH.EI in non-vaccinated population causes disruption and economic losses. To identify the risk factors associated with the EI epidemics in equids in Pakistan, a 1:1 matched case control study was conducted during 2015-2016. Including a total of 197 laboratory confirmed cases and negative controls, matched on the basis of geography, time of sampling, specie and age. A piloted questionnaire was used to collect data regarding risk factors associated with the occurrence of EI in face to face interviews. Conditional logistic regression was performed to analyze the data. A total of 16 out of 23 variabl...
Kareche H, Daly JM, Laabassi F.Equine influenza (EI) is one of the most contagious respiratory infections in horses, donkeys and mules, caused by equine influenza A virus (EIV). It remains a disease with a strong economic stake for the equine industry. This review focuses on the epidemiological situation of EIV in the Maghreb area, which includes Algeria, Morocco and Tunisia. There is serological evidence for extensive circulation of EIV in the Maghreb area since the early 1970s, but reports of detailed investigation of outbreaks are scarce with no documented isolation or molecular characterization of EIV from Tunisia. Isol...
Jensen K.Examination of nasopharyngeal secretion and organ material from clinical cases of respiratory diseases in horses, using inoculation of embryonated hen eggs and rabbit and horse kidney cell cultures, resulted in the isolation of influenza virus and herpes virus. In 2 cases, both viruses were present in the same specimen. On the basis of the physio-chemical, cytological and serological criteria, the viruses were found to be identical with influenza virus type A equi 2 and herpes virus equi type 1. The methods for serological diagnosis and characterization of the influenza and herpes viruses are ...
Adam EN, Morley PS, Chmielewski KE, Carman J, Gonzales G.Because of the contagious nature of influenza virus it is necessary to identify infected individuals after the virus is introduced into a population. The aim of this study was to characterise influenza virus detection with commercially available assays after intranasal vaccinating horses with cold-adapted influenza virus. Seven horses were vaccinated and placed with 3 unvaccinated horses. Nasal secretion samples were evaluated using 2 antigen detection assays. All 10 horses were positive in the Flu OIA assay during the study period, but only one horse was positive on one sample using the Direc...
Burton SC, Hintz HF, Kemen MJ, Holmes DF.In a study with 15 neonatal foals (5 per treatment group), foals were fed within 4 hours of birth as follows: 250 ml of colostrum, 250 ml of lyophilized serum reconstituted at 5 times the original concentration, or 250 ml of a mixture (1:1) of colostrum and lyophilized serum. Foal serum samples were tested for immunoglobulin (Ig)G concentration and titrated for anti-equine rhinovirus 1 and anti-equine influenza A1 and A2 antibodies at 0 and 24 hours after foals were born. Except in a foal which had suckled the dam before treatment, there was no evidence of IgG or specific viral antibodies in t...
Mavadiya SV, Raval SK, Mehta SA, Kanani AN, Vagh AA, Tank PH, Patel PR.A highly contagious virus infection in horses, influenza is the single most important equine respiratory disease in the world. This paper presents details of a one-year study (1 June 2008 to 31 May 2009) to determine the prevalence of equine influenza in the horses of Gujarat State in India. The prevalence of equine influenza A/equi-2 was 12.02%, but none of the samples were positive for equine influenza A/equi-1. The prevalence of equine influenza (A/equi-2) was 15.38%, 11.94%, 10.18%, and 9.09% in horses of the Kathiyawari breed, a non-descript breed, the Marwari breed and the Indian Thoroug...
