Disease outbreaks in horses refer to the occurrence and spread of infectious diseases within equine populations. These outbreaks can be caused by various pathogens, including bacteria, viruses, and parasites, and can lead to significant health issues in affected horses. Common diseases that may result in outbreaks include equine influenza, equine herpesvirus, strangles, and equine infectious anemia. The transmission of these diseases can occur through direct contact, environmental exposure, or vectors such as insects. Disease outbreaks can have substantial impacts on horse health, welfare, and the equine industry as a whole. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, transmission dynamics, and management strategies associated with disease outbreaks in equine populations.
Tillotson K, Savage CJ, Salman MD, Gentry-Weeks CR, Rice D, Fedorka-Cray PJ, Hendrickson DA, Jones RL, Nelson W, Traub-Dargatz JL.During the past 11 years, there have been numerous reports of outbreaks of salmonellosis involving horses in veterinary teaching hospitals. Some of these outbreaks have been associated with Salmonella serotypes not commonly associated with infection of horses. Salmonella infantis is among the more common Salmonella serotypes isolated from human beings, and is an important pathogen in the broiler chicken industry. However, it was not commonly isolated from horses or cattle on a national basis between 1993 and 1995. In this report, we describe an outbreak of S infantis infection among large anim...
Anzai T, Nakanishi A, Wada R, Higuchi T, Hagiwara S, Takazawa M, Oobayashi K, Inoue T.For determination whether strangles has invaded the Hidaka district of Hokkaido, the main racehorse-breeding area of Japan, a epizootiological survey with bacterial isolation was carried out during the breeding season in 1995. Streptococcus equi subsp. equi, which is the causative agent of strangles, was isolated from two Thoroughbred horses with submandibular lymphadenitis. Isolates were identified by serological grouping, biochemical tests and analysis of cell surface proteins by Western immunoblotting. Through this survey, it revealed that S. equi subsp. equi has invaded the Hidaka district...
Leroux C, Issel CJ, Montelaro RC.We have investigated the genetic evolution of three functionally distinct regions of the equine infectious anemia virus (EIAV) genome (env, rev, and long terminal repeat) during recurring febrile episodes in a pony experimentally infected with a well-characterized reference biological clone designated EIAV(PV). Viral populations present in the plasma of an EIAV(PV)-infected pony during sequential febrile episodes (18, 34, 80, 106, and 337 days postinfection) were amplified from viral RNA, analyzed, and compared to the inoculated strain. The comparison of the viral quasispecies showed that the ...
Powers AM, Oberste MS, Brault AC, Rico-Hesse R, Schmura SM, Smith JF, Kang W, Sweeney WP, Weaver SC.Venezuelan equine encephalitis (VEE) epidemics and equine epizootics occurred periodically in the Americas from the 1920s until the early 1970s, when the causative viruses, subtypes IAB and IC, were postulated to have become extinct. Recent outbreaks in Columbia and Venezuela have renewed interest in the source of epidemic/epizootic viruses and their mechanism of interepizootic maintenance. We performed phylogenetic analyses of VEE virus isolates spanning the entire temporal and geographic range of strains available, using 857-nucleotide reverse transcription-PCR products including the E3 and ...
Cohen ND.Understanding the epidemiology of equine colic is directly relevant to the management of individual horses with colic. In this article, the epidemiology of colic is reviewed with emphasis on epidemiologic studies that have identified specific factors associated with increased risk of colic and epidemiologic studies that are designed to predict the need for surgery and prognosis in horses with colic. Despite the magnitude of the problem of equine colic, much remains to be learned about the epidemiology of this disease.
Baylis M, el Hasnaoui H, Bouayoune H, Touti J, Mellor PS.African horse sickness (AHS) is a vector-borne, infectious disease of equines that is caused by African horse sickness virus (AHSV). The only proven field vector is the biting midge Culicoides imicola, although C. obsoletus and C. pulicaris are suspected vectors. There was a recent epizootic of AHS in Iberia (1987-90) and Morocco (1989-91). In 1994-45 a total of 3887 light trap samples were taken from twenty-two sites distributed over most of Morocco. Culicoides imicola was found to be very widely dispersed, with the greatest catches in the low-lying northwestern areas (between Tangier and Rab...
Riley RT, Showker JL, Owens DL, Ross PF.Fumonisin B(1), B(2), and B(3) are inhibitors of ceramide synthase, a key enzyme in the pathway for de novo sphingolipid biosynthesis. Corn, naturally contaminated with either predominantly fumonisin B(1) or pure fumonisin B(1), has been shown to cause equine leukoencephalomalacia (ELEM). It has been hypothesized that fumonisin-induced disruption of sphingolipid metabolism is an early event in the development of ELEM. Recently, it was shown that Fusarium proliferatum corn culture diets containing predominantly fumonisin B(2), but not diets which were predominantly fumonisin B(3), at 75 ppm (0....
Hartmann FA, West SE.Phenotypic and molecular techniques, including antimicrobial susceptibility testing, plasmid analysis, and pulsed-field gel electrophoresis (PFGE) were used to characterize 15 isolates of multidrug-resistant (MDR) Salmonella anatum cultured during a 16 mo period from horses and a veterinary clinic environment. The isolates were resistant to multiple antimicrobial agents and could be placed into 4 groups based on their antimicrobial resistance patterns. The isolates contained multiple plasmids ranging in size from 2 to > 100 kb that could be grouped into 3 different plasmid profile patterns;...
Takai S.An overview of epidemiology of R. equi infection in foals is presented, emphasizing the importance of the virulence-associated antigens and plasmids as epidemiological markers. The monoclonal antibody-based colony blot test has been developed to identify rapidly and accurately virulent R. equi. Epidemiological studies conducted during the recent 5 years have revealed that: (1) avirulent R. equi are widespread in the feces of horses and their environment on every farm; (2) the feces of horses and the environment of the horse farms having endemic R. equi infections demonstrated heavy contaminati...
Christensen LS.Borna disease virus has long been recognized as a cause of sporadic cases and epidemics of meningoencephalomyelitis in horses and sheep in southern parts of Germany. however, sero-epidemiological surveillances indicate that Borna disease virus has a global distribution in horses, without the recognition of clinical manifestations associated with the infection, in other parts of the world. During the past five years evidence has been presented suggesting that humans also can become infected with this virus or a closely related virus. A significantly increased sero-prevalence is seen in patient ...
Madić J, Hajsig D, Sostarić B, Curić S, Seol B, Naglić T, Cvetnić Z.An abortion outbreak occurred in a herd of 38 horses, 26 of which were pregnant mares. Twenty-one mares aborted between 5-10 months of gestation. In no case were there indications of impending abortion. Pathoanatomical, histopathological, virological and bacteriological examinations were carried out on 4 aborted fetuses. Histopathology identified Gram-negative bacteria compatible with salmonella in all 4 placentae. By subsequent bacteriological examination Salmonella abortusequi was isolated as the single causative agent in each case. Nonmotile Salmonella abortusequi with antigenic formula 4,1...
Del Piero F, Wilkins PA, Lopez JW, Glaser AL, Dubovi EJ, Schlafer DH, Lein DH.Clinical, pathological, immunohistochemical, serological and microbiological findings are described for 2 geographically and temporally distinct equine arteritis virus (EAV) epidemics in newborn foals. Outbreak A occurred at a commercial Standardbred breeding facility; Outbreak B began in a group of research animals. Clinical signs were severe and primarily referable to the respiratory tract. Fever and leucopenia and/or thrombocytopenia were observed in foals surviving for more than 24 h. The most common gross pathological findings were limited to the respiratory tract. Common histopathologica...
Sailleau C, Moulay S, Cruciere C, Laegreid WW, Zientara S.A reverse transcription-polymerase chain reaction (RT-PCR) assay followed by dot-blot hybridisation was used to detect African horse sickness virus (AHSV); the primers employed amplified the S7 gene that encodes the VP7 protein. The RT-PCR assay was compared with virus isolation for detecting AHSV in blood samples form horses experimentally infected with AHSV-4 and AHSV-9. The influence of sample storage and transportation and the effects of two anticoagulants (EDTA and heparin) were also studied. RT-PCR results were obtained within 48 hours as opposed to a minimum of 15 days for virus isolati...
Wood JL, Chanter N, Newton JR, Burrell MH, Dugdale D, Windsor HM, Windsor GD, Rosendal S, Townsend HG.Lower respiratory tract disease developed in a group of racehorses in training between two and six years of age. Disease was observed in 22 of 25 horses for which full records were available. Seroconversion to Mycoplasma felis was demonstrated by indirect haemagglutination assay in 19 of 22 paired sera and high titres (> or = 64) were found in convalescent sera from the three remaining horses. Evidence of respiratory viral infection was confined to seroconversions to equine herpesvirus-4 in two of the horses. Tracheal wash samples, taken from four horses with visibly increased tracheal muco...
Wilson WD.Myeloencephalopathy is an uncommon manifestation of equine herpesvirus 1 (EHV-1), but it can cause devastating losses during outbreaks on individual farms. Clinical signs of neurologic disease reflect a diffuse multifocal hemorrhagic myeloencephalopathy secondary to vasculitis and thrombosis. Sudden onset and early stabilization of signs, including ataxia, paresis, and urinary incontinence; involvement of multiple horses on the premises; and recent history of fever, abortion, or viral respiratory disease in the affected horse or herdmates are typical features, although there is considerable va...
Fenger CK, Granstrom DE, Langemeier JL, Stamper S.To determine the clinical findings, course of treatment, and long-term outcome of horses on a farm in central Kentucky during an epizootic of equine protozoal myeloencephalitis (EPM). Methods: Cohort study. Methods: 21 horses on a farm in central Kentucky, 12 of which developed clinical signs of EPM. Methods: Horses on the farm were serially examined for signs of neurologic disease and serum and CSF antibodies to Sarcocystis neurona. Horses were considered to have EPM if they had neurologic signs and positive test results for antibodies to S neurona in CSF. Blood values were monitored for evid...
Kaneene JB, Miller R, Ross WA, Gallagher K, Marteniuk J, Rook J.A population-based prospective epidemiological study was conducted to assess risk factors for equine colic. A stratified sample of 3925 equids in 138 randomly selected equine farms in the state of Michigan was monitored in two 12-month rounds of data collection. Incidence densities were used to describe the rate of development of colic in the study population. Mortality rates, case fatality rates and survival rates were used to describe the severity of colic on the study population. Multivariable logistic regressions with random effects (grouped according to farm) were used to identify risk fa...
Li F, Drummer HE, Ficorilli N, Studdert MJ, Crabb BS.Equine rhinovirus 1 (ERhV1) is a recognized cause of acute febrile respiratory disease in horse, although the virus is rarely isolated from such animals, despite seroprevalence rates as high as 50% in some horse populations. Recently, ERhV1 has been shown to be most closely related to foot-and-mouth disease virus, raising questions as to its disease associations in horses. We report that ERhV1 infection was the likely cause of two separate outbreaks of severe febrile respiratory disease which involved more than 20 horses. Attempts to isolate ErhV1 from nasopharyngeal swabs by conventional cell...
Lord CC, Woolhouse ME, Mellor PS.A simulation model including two hosts (horses and donkeys) and one vector (Culicoides imicola) for African horse sickness in Spain is extended to consider vaccination strategies. If hosts were protected prior to virus introduction, elimination of simulated epidemics was related nonlinearly to the fraction protected. Protecting donkeys as well as horses increased the effectiveness of vaccination. Prevention of 50% of epidemics required 75% coverage of horses and donkeys or 90% coverage of horses only. Protection after the introduction of the virus was rarely successful in preventing outbreaks....
Rivas F, Diaz LA, Cardenas VM, Daza E, Bruzon L, Alcala A, De la Hoz O, Caceres FM, Aristizabal G, Martinez JW, Revelo D, De la Hoz F, Boshell J....In 1995, the first Venezuelan equine encephalitis (VEE) outbreak in Colombia in 22 years caused an estimated 75,000 human cases, 3000 with neurologic complications and 300 fatal, in La Guajira State. Of the state's estimated 50,000 equines, 8% may have died. An epizootic IC virus, probably introduced from Venezuela, was rapidly amplified among unvaccinated equines. Record high rainfall, producing high densities of vector Aedes taeniorhynchus, led to extensive epidemic transmission (30% attack rate) in the four affected municipalities. Native Wayuu Indians, constituting 24% of the state's popul...
Watson ED.Outbreaks of contagious equine metritis in Britain during 1996 emphasised the importance of preventing the disease through full and widespread implementation of the Horserace Betting Levy Board's code of practice. The provision of satisfactory samples for testing represents an integral part of applying the code. Here, in an article commissioned by the British Equine Veterinary Association, Dr Elaine Watson describes the techniques involved.
Lány P, Pospísil Z, Zendulková D, Cíhal P, Jahn P.A mild outbreak of acute respiratory infection was reported in racing horses in the fall of 1995. Four studs were investigated for the sources and routes of infection. In five horses from two herds, virus isolates were obtained which, in preliminary typing experiments, were identified as the influenza A/equi 2 virus. The presence of this illness in all the examined herds was confirmed by a rise in specific antibody titres. The affected animals included both older vaccinated horses and young horses not yet vaccinated. Epidemiological studies suggested that the spread of infection occurred in si...
Newton JR, Wood JL, Dunn KA, DeBrauwere MN, Chanter N.During an outbreak of strangles on a farm with approximately 1500 horses, the spread of Streptococcus equi infection was monitored by repeated nasopharyngeal swabbing and culture. In order to control the infection and prevent new introductions of strangles on to the premises, a system of quarantine and swabbing of cases and all incoming animals was instituted. Long-term carriage of the organism was detected in four clinically healthy convalescent animals, and in two of 350 new ponies; it persisted for between seven and 39 months, but it was detected only intermittently by the culture of swabs ...
Bowling AT, Byrns G, Spier S.The pedigree origin of a base pair substitution in the horse muscle sodium channel gene that confers susceptibility to the muscle disease hyperkalemic periodic paralysis (HYPP) was investigated with a set of 978 Quarter Horses. The horses were chosen at random, based on a collection of blood samples taken between 1989 and 1991 to meet parentage testing requirements, primarily but not exclusively from breeding stallions. The frequency of Quarter Horses positive for the base pair substitution, all heterozygotes, was 4.4%, which corresponds to an allelic frequency of 0.02. All horses positive for...
Issel CJ, Adams WV.In 1975, a survey was conducted in East Baton Rouge Parish, Louisiana, to determine the prevalence of equine infectious anemia. Using the agar gel immunodiffusion test, 94 of 1,398 horses (6.7%) were found to be infected. Infection rates were especially high in areas where clinical cases of equine infectious anemia had been diagnosed. Clinical signs compatible with the disease were noted in 1 of the 94 seropositive horses. The sample set of 1,398 horses represented 22% of the census population obtained during the 1971 Venezuelan equine encephalomyelitis vaccination campaign.
de Almeida Campos AC, Cicolo S, de Oliveira CM, Molina CV, Navas-Suárez PE, Poltronieri Dos Santos T, da Silveira VB, Barbosa CM, Baccarin RYA....Equid herpesvirus (EHV) commonly affects horses causing neurologic and respiratory symptoms beside spontaneous abortions, meaning huge economic losses for equine industry worldwide. In foals, the virus can facilitate secondary infections by Rhodococcus equi, important in morbidity and mortality in equines. A total of five genotypes of EHV were previously described in Brazil including EHV-1, EHV-2, EHV-3, EHV-4, and EHV-5. EHV-2 genotype had only been previously described in Brazil in asymptomatic animals. We report the investigation of the dead of 11 foals in Middle-west region of Brazil showi...
Potier JFN, Durham AE.Responsible use of antimicrobials in equine practice relies on knowledge of common bacterial isolates and their antimicrobial sensitivities. Objective: To assess the frequency of bacterial resistance to a combination of parenteral penicillin and gentamicin and to trimethoprim and sulfamethoxazole for PO use in a selection of clinical isolates, and subsequently to determine the prevalence of resistance to antimicrobials that might then be used as alternatives to first-line antimicrobials for the same isolates. Methods: Retrospective analysis of minimal inhibitory concentrations (MICs) of antimi...
Bello AC, Da Cunha AP, Leite RC, Oliveira PR, Ribeiro AC, Domingues LN, De Freitas CM, Bastianetto E, Dalla Rosa RC.This trial evaluated control practices of Anocentor nitens on equines, using spraying devices and application of acaricide paste formulation in the auricular pavilion and nasal diverticulum. The study was carried out from October 2003 to March of 2008 and the evaluations had been divided in the following stages: Phase 1--out/03 mar/04 and Phases 2, 3, 4 and 5, respectively, correspondents to the month's periods until março/08. It was used score of 0 to 3 to classify infestation levels. From abr/04 to mar/06 was implanted a schedule of acaricide sprayings every seven days and divided in two se...
Yuen KY, Gibson JS, Hinrichsen S, Medina-Torres CE, Bertin FR, Stewart AJ.Prudent use of antimicrobials is paramount to slow the development of resistance and for successful treatment. The use of cumulative antibiograms will allow evidence-based antimicrobial selection with consideration of local resistance patterns. We generated a "first-isolate-per-patient" cumulative antibiogram for a regional equine referral hospital. Bacterial organisms cultured from horses between 2011 and 2018, sample origin, antimicrobial susceptibilities, and multidrug-resistant (MDR) status were tabulated. Of 1,176 samples, 50% were culture positive. Overall, 93 of 374 (25%) were MDR. Of t...
Fonseca AO, Botton Sde A, Nogueira CE, Corrêa BF, Silveira Jde S, de Azevedo MI, Maroneze BP, Santurio JM, Pereira DI.Pythium insidiosum is an important pathogen of mammals' species, including humans. Equine is the main species affected by this oomycete. P. insidiosum requires an aquatic environment to develop its life cycle, and the susceptible hosts are contaminated when they contact the microorganism in swampy areas. The equine pythiosis is characterized by the formation of irregular masses within the cutaneous lesions, called kunkers, which easily detach from the lesion. From these structures, it is possible to isolate P. insidiosum in pure cultures. The present study aimed to reproduce in vitro the life ...
Hughes JP.Contagious Equine Metritis (CEM) is a highly contagious venereal disease of horses caused by a fastidious, Gram-negative coccobacillus which grows best on chocolate agar under microaerophilic conditions (5-10% CO2). Clinically, the disease is characterized by a copious watery-to-mucopurulent, vaginal discharge two to ten days after breeding by an infected stallion (11, 13). Shortened estrous cycle lengths are common and may be the only indication of endometritis in some instances (7). Inapparent carriers of the disease in both the mare and stallion make control of the disease more difficult. O...
Barbosa JD, Lins AMC, Bomjardim HDA, Silveira NDSES, Barbosa CC, Beuttemmuller EA, Brito MF, Salvarani FM.An investigative and epidemiological study was carried out for equine herpesvirus type 1 (HVE-1) in 10 outbreaks of neurological disease from different farms in the state of Pará, Brazil. 25 horses were studied: six male and 19 females, aged between one and 13 years. A necropsy of six horses was performed, and the others recovered either with or without treatment (T1-vitamin B1 + dexamentasone; T2-vitamin B1 + flunixim meglumine). Animals that received treatment recovered after eight days. The main clinical signs observed were motor incoordination, progressive paresis, thoracic and/or pelvic ...
Tapprest J, Foucher N, Linster M, Laloy E, Cordonnier N, Amat JP, Hendrikx P.The French surveillance network for causes of equine mortality (Resumeq) was created in 2015 for the qualitative surveillance of equine mortality through the centralization in a national database of necropsy data and their subsequent epidemiological analysis. It was designed to identify the causes of equine mortality, monitor their evolution over time and space, and detect emerging diseases as early as possible. Resumeq is an event-based surveillance system involving various players and structures. It is organized around a steering body, a scientific and technical support committee and a coord...
Alaql FA, Alhafufi AN, Kasem S, Alhammad YMO, Albaqshi H, Alyousaf A, Alsubaie FM, Alghamdi AN, Abdel-Moneim AS, Alharbi SA.Equine influenza is a major cause of respiratory infections in horses and can spread rapidly despite the availability of commercial vaccines. This study aimed to screen the incidence of equine influenza virus (EIV) and molecularly characterize the haemagglutinin and neuraminidase from positive EIV field samples collected from Saudi Arabia. Six-hundred twenty-one horses from 57 horse barns were screened for the presence of the clinical signs, suggestive for equine influenza, from different parts of Saudi Arabia. Nasopharyngeal swabs were collected from each horse showing respiratory distress. S...
Sergeant ES, Kirkland PD, Cowled BD.During the Australian epidemic of equine influenza in 2007, tens of thousands of horses were infected. From the resulting field data, 475 known infected and 1323 uninfected horses were identified to allow a post outbreak evaluation of the performance of the commonly used bELISA for influenza A under field conditions. A variety of techniques, such as ROC plots, area under the curve and hypothesis testing were used to assess the overall performance of the test. The test was deemed to be accurate (area under curve=0.993+/-0.003 standard error) and significantly informative (z=-32.0; p or =50) wer...
Milwid RM, O'Sullivan TL, Poljak Z, Laskowski M, Greer AL.Disease transmission models often assume homogenous mixing. This assumption, however, has the potential to misrepresent the disease dynamics for populations in which contact patterns are non-random. A disease transmission model with an SEIR structure was used to compare the effect of weighted and unweighted empirical equine contact networks to weighted and unweighted theoretical networks generated using random mixing. Equine influenza was used as a case study. Incidence curves generated with the unweighted empirical networks were similar in epidemic duration (5-8 days) and peak incidence (30.8...
Singh BR, Gulati BR, Virmani N, Chauhan M.At a thoroughbred equine breeding farm near Hissar (Haryana), three mares aborted in their seventh month of pregnancy. The vaginal swabs of all aborted mares, and stomach contents, heart blood, liver, spleen and placenta of aborted fetuses yielded pure culture of Aeromonas hydrophila. In addition, A. hydrophila was also isolated from the vaginal swabs of three repeat breeding mares and faecal sample of a diarrheic foal. The source of infection was possibly water supply as all the water samples collected from taps, mother tank and storage tank were found to be positive for A. hydrophila. The an...
Levasseur A, Arsenault J, Paré J.West Nile virus (WNV) became notifiable in horses in 2003 in Canada and has been reported every year since. The objective of this study was to describe the spatiotemporal distribution of WNV in horses between 2003 and 2020 in Canada. Methods: The 848 symptomatic and laboratory-confirmed WNV cases in horses reported to the Canadian Food Inspection Agency between 2003 and 2020. Methods: Canada was divided into eastern and western regions for analysis. For each case, location and date of notification were captured. Triennial maps were made to describe the spatiotemporal distribution and expansion...
Desmettre P.The frequent transfers of horses, whether on a permanent or temporary basis, make strict control of infectious diseases essential. Such control needs a reliable and rapid means to accurately diagnose the relevant diseases. Indirect diagnosis based on antibody detection remains certainly the best method to secure the epidemiologic surveillance of the diseases at regional, national, or even world level, while direct diagnosis is the only way to diagnose a new outbreak. New diagnostic methods resulting from advances in biochemistry, molecular biology, and immunology are now available. As far as a...
Salmonella enterica subsp. enterica serovar Abortusequi (S. Abortusequi) is a serotype restricted to equines, which produces abortion outbreaks. Nowadays the disease is being reported in different countries including Argentina thus generating an important impact in the equine industry. Molecular characterization of the 95 kb virulence plasmid and the spvC gene of S. Abortusequi demonstrated their importance in the pathogenicity of the serotype. In the last decades, high clonality of S. Abortusequi was identified in Japan, Mongolia and Croatia. Objective: The aim of this work was to characteriz...
Debey MC, Bailie WE.Horse farms in Kansas were surveyed for the incidence of Rhodococcus equi. Fecal specimens and soil or cobweb samples were collected from each farm and cultured on selective media. One control farm (with no history of R. equi infection), one farm which had an outbreak 3 and 4 years previously and 2 farms which had R. equi-infected foals that season were surveyed. In addition, fecal samples from 21 horses hospitalized in the Kansas State University Veterinary Hospital were cultured. There was no significant difference in the incidence of R. equi in fecal samples from the 2 farms with recent dis...
Schemann K, Gillespie JA, Toribio JA, Ward MP, Dhand NK.Rapid, evidence-based decision-making is critical during a disease outbreak response; however, compliance by stakeholders is necessary to ensure that such decisions are effective - especially if the response depends on voluntary action. This mixed method study evaluated technical policy decision-making processes during the 2007 outbreak of equine influenza in Australia by identifying and analysing the stakeholder network involved and the factors driving policy decision-making. The study started with a review of the outbreak literature and published policy documents. This identified six policy ...
Sellers RF, Maarouf AR.Cases of western equine encephalitis in horses in 1987 in western USA and Manitoba, Canada were examined by backward trajectory analysis of winds. Culex tarsalis mosquitoes infected with western equine encephalitis virus could have been carried on southerly winds from Texas and Oklahoma to northern USA and from there to Manitoba. The presence of the Polar front over North Dakota and Minnesota at the end of July would have led to the landing of Cx. tarsalis in Montana and Wisconsin and prevented further carriage into Manitoba. Temperatures in southern Texas during the winter months (average dai...
Velineni S, Breathnach CC, Timoney JF.Streptococcus zooepidemicus (Sz) is a tonsillar commensal of healthy horses but with potential to opportunistically invade the lower respiratory tract. Sz is genetically variable and recombinogenic based on analysis of gene sequences including szp, szm and MLST data. Although a variety of serovars of the protective SzP are commonly harbored in the tonsils of the same horse, lower respiratory infections usually involve a single clone. Nevertheless, isolation of specific clones from epizootics of respiratory disease has been recently reported in horses and dogs in N. America, Europe and Asia. In...
Sherman J, Mitchell WR, Martin SW, Thorsen J, Ingram DG.The outbreaks of upper respiratory tract infections in horses at Standardbred racetracks were investigated over a three year period. The most serious epidemics of respiratory disease occurred in the winter and spring seasons. Both influenza viruses and equine herpesvirus 1 were shown to be present in the horse population. The herpesvirus was associated with respiratory disease particularly in the winter but the equine influenza viruses apparently were responsible for the major epidemics of respiratory disease at these tracks. Younger horses, two or three years of age, were particularly suscept...
Black P, Douglas I, Field H.Hendra virus was first described in 1994 in Australia, causally associated with a cluster of fatal equine and human cases at a thoroughbred racing stable in the Brisbane suburb of Hendra. This year marks the twentieth anniversary of the identification of pteropid bats (flying-foxes) as the natural host of the virus, and it is timely to reflect on a pivotal meeting of an eclectic group of scientists in that process. They included animal and public health experts, environmental scientists, veterinary and horse industry representatives, and wildlife experts. The task was to review and prioritise ...
Takeishi M, Kuwata R, Ono T, Sasaki A, Ogata M, Iwata E, Taji S, Koike M, Nemoto M, Bannai H, Isawa H, Maeda K, Morikawa S, Kitagawa H, Yoshikawa Y.Getah virus (GETV), an arthropod-borne virus transmitted by mosquitoes, has been isolated from several animals. GETV infection in horses shows clinical signs such as fever, rash, and edema in the leg. Noma horses are one of the eight Japanese native horses. The present study aimed to clarify the occurrence of GETV infection in Noma horses. Serum samples collected from Noma horses were analyzed using a virus neutralization test and enzyme-linked immunosorbent assay and showed that the anti-GETV antibody titers in the samples collected in 2017 were significantly higher than those collected in 20...
Glaser AL, Renshaw RW, Trock SC, Brady RC, Dubovi EJ.Salem virus (SalV) is a recently identified equine virus belonging to the family Paramyxoviridae. The only known isolate was obtained from a horse that was involved in a disease outbreak of undetermined nature and the circumstances of its isolation suggested an etiologic role. However, the experimental infection of a colostrum-deprived foal failed to reproduce the disease; only mild neutropenia and temperature elevation were recorded. An additional attempt to establish an etiological relationship with the disease was made by conducting a retrospective evaluation of the serological profiles of ...
Hartig W, Houe H, Andersen PH.The plentiful data on Danish horses are currently neither organized nor easily accessible, impeding register-based epidemiological studies on Danish horses. A common database could be beneficial. In principle, databases can contain a wealth of information, but no single database can serve every purpose. Hence the establishment of a Danish equine health database should be preceded by careful consideration of its purpose and content, and stakeholder attitudes should be investigated. The objectives of the present study were to identify stakeholder attitudes to the importance, purpose, research ar...
Pereira HG, Takimoto S, Piegas NS, do Valle LA.Influenza equine (Heq2Neq2) strains isolated during the course of epizootics observed in Guanabara (Rio de Janeiro) and São Paulo, Brazil, in July-October 1969 were shown to differ antigenically from earlier strains of the same subtype (A/equine/Miami/1/63 (Heq2Neq2)). The difference could be clearly demonstrated in haemagglutination inhibition tests performed with postinfection horse or ferret sera but not with hyperimmune rooster sera. Antibody responses of diseased horses were higher and more frequent against current isolates than against strain equine/Miami/1/63. Some animals also showed ...
Issel CJ, McManus JM, Hagius SD, Foil LD, Adams WV, Montelaro RC.Equine infectious anemia has been managed in most countries by the imposition of testing and quarantine regulations. In the United States, about 700,000 of the more than 7,000,000 horses are tested annually. As long as the status of greater than 90% of the horse population remains unknown and horses are transported and congregate in a relatively unrestricted manner, EIA will continue to exact its toll. Therefore, it is incumbent on the scientific community to continue to develop and refine practical and sensitive diagnostic tests for EIA which will be used in an expanding market, to reduce the...
Rosanowski SM, Carpenter TE, Adamson D, Rogers CW, Pearce P, Burns M, Cogger N.Equine influenza (EI) is an infectious respiratory disease of horses that has never been reported in New Zealand (NZ). However, the 2007 EI outbreak in Australia, previously EI free, spurred the NZ government and stakeholders into evaluating alternative EI control strategies in order to economically justify any future decision to eradicate or manage EI. To build on the policy debate, this paper presents an epinomic (epidemiologic and economic) modelling approach to evaluate alternative control strategies. An epidemiologic model to determine how alternative EI control strategies influence the d...
Sebastian MM, Stewart I, Williams NM, Poonacha KB, Sells SF, Vickers ML, Harrison LR.Pathological, entomological and avian investigations were conducted during the summer of 2002, in a horse farm that had four cases of West Nile virus (WNV) infection in horses. All the four horses had encephalitis and WNV infection was confirmed by RT-PCR and in situ hybridization procedure. Forty-seven per cent of house sparrows that resided on the farm were tested positive for WNV infection. Mosquitoes (98%Culex pipiens) collected by trapping at the farm, during this period were positive for WNV. The meteorological data for year 2002 were compared to previous 16 years. The precipitation and ...
