Epidemiology in horses involves the study of the distribution and determinants of health-related states and events in equine populations. It encompasses the investigation of patterns, causes, and effects of diseases and health conditions within horse populations. This field of study aims to identify risk factors for disease and targets for preventive healthcare. Key components of equine epidemiology include disease surveillance, outbreak investigation, and the study of disease dynamics within herds or regions. Research in this area often focuses on infectious diseases, zoonotic diseases, and the impact of environmental factors on equine health. This page compiles peer-reviewed research studies and scholarly articles that explore various aspects of epidemiology in horses, including disease prevalence, transmission pathways, and strategies for disease prevention and control.
Artiushin S, Tong Y, Timoney J, Lemieux B, Schlegel A, Kong H.A simple and portable assay for detection of Streptococcus equi subspecies equi has been developed based on amplification of S. equi-specific sequence using a thermophilic helicase-dependent reaction followed by visual detection of the amplicon in a disposable lateral flow cassette. An experimental kit (IsoAmp™ SE) was evaluated. Analytical sensitivity was 50 copies of S. equi genomic DNA per reaction. The IsoAmp SE assay had 100% specificity when applied to nasal swabs and washes. The assay was more sensitive than culture but less sensitive than nested polymerase chain reaction (PCR). The t...
Silva ML, Galiza GJ, Dantas AF, Oliveira RN, Iamamoto K, Achkar SM, Riet-Correa F.Outbreaks of eastern equine encephalitis observed from May 2008 to August 2009 in the Brazilian states of Pernambuco, Ceará, and Paraíba are reported. The disease occurred in 93 farms affecting 229 equids with a case fatality rate of 72.92%. Main clinical signs were circling, depression or hyperexcitability, ataxia, and progressive paralysis with a clinical manifestation period of 3-15 days. Main histologic lesions were a diffuse lymphocytic encephalomyelitis with neuronal death, satellitosis, neuronophagia, and hemorrhages being more severe in the cerebral gray matter of the telencephalon, ...
Khan I, Wieler LH, Melzer F, Gwida M, Santana VL, de Souza MM, Saqib M, Elschner MC, Neubauer H.The sensitivity and specificity of three commercially available complement fixation test (CFT) antigens from c.c.pro (c.c.pro), Central Veterinary Institute of Wageningen UR (CIDC) and the United States Department of Agriculture (USDA) were comparatively evaluated by testing 410 sera collected from glanders-endemic and non-endemic areas (200 true-negative randomly collected sera and 210 sera collected from experimentally immunised animals (12 rabbits, 19 horses), clinically positive (135) and culture-positive (44) horses, donkeys and mules). Immunoblotting (IB) was used as the gold standard te...
Lykkjen S, Roed KH, Dolvik NI.Developmental orthopaedic diseases (DOD) such as osteochondrosis (OC)/osteochondrosis dissecans (OCD), palmar/plantar osteochondral fragments (POF), ununited palmar/plantar eminences (UPE) and dorsoproximal first phalanx fragments are well recognised in the horse. Aetiopathogeneses are controversial and molecular genetic screening of DNA has recently been employed for their elucidation. Precise phenotypic definition and knowledge of breed-specific prevalence and interrelations are essential for the interpretation of following genomic studies in Standardbred trotters. Objective: To assess the p...
Schemann K, Taylor MR, Toribio JA, Dhand NK.A cross-sectional study was conducted involving 759 Australian horse owners to determine their biosecurity practices and perceptions one year after the 2007 equine influenza outbreak and to investigate the factors influencing these perceptions and practices. A web link to an online questionnaire was sent to 1224 horse owners as a follow-up to a previous study to obtain information about biosecurity perceptions and practices, impacts of the 2007 EI outbreak, demographic information and information about horse industry involvement. Ordinal logistic regression analyses were conducted to determine...
Hampson BA, Owens E, Watts KA, Mills PC, Pollitt CC, de Laat MA.To determine the impact of a free-choice diet on nutritional intake and body condition of feral horses. Methods: Cadavers of 41 feral horses from 5 Australian locations. Methods: Body condition score (BCS) was determined (scale of 1 to 9), and the stomach was removed from horses during postmortem examination. Stomach contents were analyzed for nutritional variables and macroelement and microelement concentrations. Data were compared among the locations and also compared with recommended daily intakes for horses. Results: Mean BCS varied by location; all horses were judged to be moderately thin...
first infected cases caused by West Nile virus were reported in Cuba in 2004. Objective: to monitor and learn about the prevalence of the West Nile virus in those areas with confirmed cases. Methods: the study was conducted in Jatibonico municipality and in the city of sancti Spiritus. A total number of 14 persons, 8 horses and 41 birds were researched to detect antibodies to flavivirus and specific antibodies to West Nile virus. Results: the presence of specific antibodies to West Nile virus was confirmed in 4 samples of sera from birds and in 4 from horses. One person was confirmed as one ca...
Sieber S, Gerber V, Jandova V, Rossano A, Evison JM, Perreten V.A total of 70 Staphylococcus aureus isolates from postoperative infections in hospitalized horses were isolated between January 2005 and January 2011. Among them, 12 isolates were methicillin-susceptible S. aureus (MSSA), 18 were borderline-oxacillin-resistant S. aureus (BORSA), and 40 were methicillin-resistant S. aureus (MRSA). During the same period, the equine clinic personnel were screened for nasal carriage of BORSA and MRSA. Genotyping revealed that BORSA ST1(MLST)-t2863(spa) isolates were responsible for most equine infections and were the main isolates found in colonized members of th...
Taddei L, Benoit M, Sukta A, Peterson J, Gaensslen RE, Negrusz A.In order to protect the integrity of horse racing in Illinois, a complex testing of urine and blood specimens collected post-race from winning and special designation horses is continuously conducted. The initial screening by immunoassays was followed by the confirmation on presumptive positive samples. Instrumental screening was also conducted. Perimortem and postmortem specimens and special exhibits (syringes, needles, etc.) were also analyzed. The administration of alkalinizing agents was detected by measuring the total plasma carbon dioxide concentration. The laboratory analyzed specimens ...
Nemoto M, Yamanaka T, Bannai H, Tsujimura K, Kondo T, Matsumura T.Reverse transcription loop-mediated isothermal amplification (RT-LAMP) was applied to the detection of equine influenza virus (EIV). Because equine influenza is caused currently by EIV of the H3H8 subtype, the RT-LAMP primer set was designed to target the hemagglutinin gene of this subtype. The detection limit of the RT-LAMP assay was a virus dilution of 10(-5); which was 10(3) times more sensitive than the Espline Influenza A&B-N test and 10 times more sensitive than a reverse transcription polymerase chain reaction (RT-PCR) assay. The specificity of the RT-LAMP assay was examined by usin...
Curling A.Equine recurrent uveitis is a cyclical disease that affects the eye and often leads to high management costs and unfavorable results, such as blindness. Research has improved understanding of the roles of various etiologies, especially leptospirosis, in initiating and perpetuating the pathogenesis of equine recurrent uveitis. Research has also led to the discovery that specific breeds and horses with specific coat color patterns may be predisposed to developing recurrent uveitis.
Boyle A.Streptococcus equi subspecies equi (strangles) is a highly contagious upper respiratory infection in horses. The infection is transmitted by inhalation or direct contact with mucopurulent discharge from an infective animal, resulting in fever, depression, and submandibular and retropharyngeal lymph node enlargement that can lead to respiratory distress. Complications include purpura hemorrhagica and metastatic abscessation. Control of outbreaks requires strict isolation protocols and hygiene measures. Detection of carriers is essential for preventing disease recurrence on a farm.
Knight PK, Thomson PC.OBJECTIVE Compare the career profiles of a cohort of Standardbred horses that first raced as 2-year-olds with those that started their racing careers at a later age. METHOD Retrospective analysis of the racing records of all foals born in New South Wales in the 2000 foaling season. RESULTS The career records of 999 horses were analysed. Almost half (43.9%) first raced as 2-year-olds and one-third (33.9%) as 3-year-olds. The median career duration for horses that first raced as 2-year-olds was 2.93 years (interquartile range (IQR) 2.70-3.16), which was significantly greater than the median for ...
Vallance SA, Spriet M, Stover SM.To enhance understanding of the nature and pathogenesis of scapular fractures in racehorses. Objective: Scapular fractures in racehorses have a consistent configuration related to sites of pre-existing stress modelling and remodelling. Methods: Fractured and intact scapulae collected post mortem were examined visually and with computed tomography (CT). Scapular fracture configuration, bone modelling changes and standardised CT morphometry and density measurements were recorded. Statistical comparisons were made between fractured, nonfractured contralateral and control scapulae. Results: Thirty...
Breuer J, Schmoll F, Uhlig A, Schusser GF.Equine proliferative enteropathy (EPE) caused by Lawsonia (L.) intracellularis is an emerging disease in foals, particularly in North America. Since a case report in Germany exists, the objective of this study was to examine the incidence of L. intracellularis-antibodies in healthy horses from two German breeding farms. In group 1, serum samples from 24 (year 1) and 16 (year 2) Haflinger mares and their foals were taken. In group 2, over a period of five months, serum samples of six warmblood mares and foals were collected monthly from birth until the foals became seronegative. Serum samples w...
Maddox TW, Pinchbeck GL, Clegg PD, Wedley AL, Dawson S, Williams NJ.The increasing prevalence of antimicrobial resistant bacteria such as antimicrobial-resistant and extended spectrum β-lactamase (ESBL)-producing Escherichia coli represents a significant problem for human and veterinary medicine. Despite this, the risk factors for faecal carriage of such bacteria by horses in the UK, particularly those in the wider community, have not been well described. Objective: To characterise the risk factors for faecal carriage of antimicrobial-resistant E. coli amongst horses in the mainland UK. Methods: A cross-sectional study of horses recruited by 65 randomly selec...
Maddox TW, Clegg PD, Diggle PJ, Wedley AL, Dawson S, Pinchbeck GL, Williams NJ.The increasing prevalence of antimicrobial-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and antimicrobial-resistant Escherichia coli represents a significant problem. However, the carriage of such bacteria by horses in the UK has not been well characterised. Objective: To estimate the prevalence of nasal carriage of MRSA and faecal carriage of antimicrobial-resistant E. coli amongst horses in the general equine community of the mainland UK. Methods: A cross-sectional study of horses recruited by 65 randomly selected equine veterinary practices was conducted, wi...
Wagner B, Freer H, Rollins A, Erb HN, Lu Z, Gröhn Y.Lyme disease is a zoonotic, vector-borne disease and occurs in mammals including horses. The disease is induced by infection with spirochetes of the Borrelia burgdorferi sensu lato group. Infection of mammalian hosts requires transmission of spirochetes by infected ticks during tick bites. Lyme disease diagnosis is based on clinical signs, possible exposure to infected ticks, and antibody testing which is traditionally performed by ELISA and Western blotting (WB). This report describes the development and validation of a new fluorescent bead-based multiplex assay for the detection of antibodie...
Kirkland PD, Davis RJ, Wong D, Ryan D, Hart K, Corney B, Hewitson G, Cooper K, Biddle A, Eastwood S, Slattery S, Rayward D, Evers M, Wright T....Until August 2007, Australia was one of only three countries internationally recognised to be free of equine influenza (EI). This report documents the diagnosis of the first cases of EI in Australian horses and summarises the investigations that took place over the next 5 days. During that time, a multifocal outbreak was identified across eastern New South Wales and south-eastern Queensland. The use of an influenza type A pan-reactive real-time reverse transcription polymerase chain reaction allowed rapid confirmation of suspect cases of EI.
Major DA.This paper describes a protocol for hygiene practices that was devised by a practice in which all veterinarians were involved on a daily basis in visiting infected premises, including sampling, treatment of clinical cases and general veterinary work. This protocol was strictly followed when attending an infected or at risk property.
Major DA, Jones B.We describe the behaviour of equine influenza (EI) virus infection in a naïve population as observed by equine veterinary practitioners. The clinical signs displayed by infected horses and the highly contagious nature of the disease are discussed, as well as the treatment and management of infected horses.
Gilkerson JR.The clinical symptoms observed during the 2007 equine influenza outbreak are compared and contrasted with those observed in overseas outbreaks and described in the veterinary literature.
Minke JM, El-Hage CM, Tazawa P, Homer D, Lemaitre L, Cozette V, Gilkerson JR, Kirkland PD.The results of an accelerated immunisation schedule for horses used as part of the emergency response plan to contain and eradicate equine influenza in Australia in 2007 is described. The horses studied were vaccinated with a recombinant canarypox-vectored vaccine (ProteqFlu®, Merial) with a shorter interdose interval. Vaccinated horses included foals aged less than 4 months.
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.
Arias MS, Piñeiro P, Hillyer GV, Francisco I, Cazapal-Monteiro CF, Suárez JL, Morrondo P, Sánchez-Andrade R, Paz-Silva A.The utility of an enzyme-linked immunosorbent assay to determine the sensitization against the trematode Fasciola hepatica in horses from an endemic area (NW Spain) was assessed. Blood samples were collected from 536 horses and tested against a 2.9-kDa recombinant surface protein (FhrAPS) to estimate the presence of IgG antibodies. Data were analysed regarding several intrinsic (age, gender and breed) and extrinsic factors (aptitude and housing). The farm size (number of horses/farm) was also considered. Sixty percent (95% CI 56, 64) of the horses were positive to the FhrAPS-ELISA, with a sign...
Carr E, Schott H, Pusterla N.Equid herpesvirus-1 (EHV-1) reactivation and shedding can occur in latently infected, asymptomatic animals. Risk factors for reactivation include stress and illness. The risk of asymptomatic shedding in hospitalized, critically ill horses with acute abdominal disease is unknown. This information is important to assess the need for additional biosecurity protocols to prevent spread of EHV-1 in hospitalized critically ill horses with acute abdominal disorders. Objective: To determine the frequency of reactivation and nasal shedding of EHV-1 in hospitalized critically ill horses. Methods: One hun...
Bracken MK, Wøhlk CB, Petersen SL, Nielsen MK.Strongyle parasites are ubiquitous in grazing horses. Of these, the bloodworm Strongylus vulgaris is regarded as most pathogenic. Increasing levels of anthelmintic resistance in strongyle parasites has led to recommendations of decreased treatment intensities, and there is now a pronounced need for reliable tools for detection of parasite burdens in general and S. vulgaris in particular. The only method currently available for diagnosing S. vulgaris in practice is the larval culture, which is laborious and time-consuming, so veterinary practitioners most often pool samples from several horses ...
Richey MT, Holland MS, McGrath CJ, Dodman NH, Marshall DB, Court MH, Norman WM, Seeler DC.The incidence of post-anesthetic lameness in 655 horses undergoing 733 anesthetic episodes over a 3 year period was 6.4%. Nineteen factors previously reported or proposed to play a role in the development of post-anesthetic lameness were evaluated statistically. Only hypotension and the duration of the anesthetic period were significant factors.
West Nile Virus (WNV) is a mosquito-borne virus enzootically maintained in birds. However, it can incidentally infect other species, leading to sometimes severe clinical consequences like in horses and especially human beings. Despite the topic relevance, the presence and distribution of WNV are currently unknown in Namibia. Several countries implement surveillance systems based on virus detection in birds, mosquitoes, and vertebrate species including horses. The present study aimed to fill this knowledge gap by serologically evaluating WNV exposure in Namibian donkeys, whose population is rem...
Owen RA, Jagger DW, Quan-Taylor R.The prevalence of Anoplocephala perfoliata in 103 horses and ponies from Clwyd, Powys and the adjacent English marches, slaughtered during January 1987, was 69 per cent.
Donati B, Fürst AE, Hässig M, Jackson MA.Fractures occur commonly in equids and often are associated with complications and a poor outcome. There are no reports on the epidemiology of fractures in a heterogeneous equine population. Objective: To study the epidemiology of fractures in a heterogeneous equine population, focusing on differences between fractures resulting from a kick and fractures, resulting from other causes and investigating predictors for recovery. Methods: Retrospective case series. Methods: Data of all equids presented to the Equine Department, Vetsuisse Faculty, University of Zurich between 1990 and 2014 and diagn...
Ricard A, Blouin C.The longevity of sport horses is an economic and ethical issue. The aim of this study was to analyze the duration of the competitive life of jumping horses in France to assess the potential for genetic evaluation and to propose rules of management for sport horses. Data included lifetimes spent in jumping competitions for the 209,296 horses born from 1968 onward with performances between 1972 and 2008; the data set contained 22% right-censored records. Longevity was measured in years. Discrete survival analysis included fixed effects of region of birth, month of birth, year of recording, age a...
Bandarra PM, Pavarini SP, Raymundo DL, Corrêa AM, Pedroso PM, Driemeier D.After ingesting green leaves of T. micrantha, 2 horses showed apathy, locomotor deficit, blindness, recumbency, paddling, coma and death. The main gross findings were scattered haemorrhages, enhanced lobular pattern of the liver, and cerebral oedema. Histological changes included disseminated haemorrhages, massive hepatocellular necrosis, neuronal degeneration, Alzheimer type II astrocytes and cerebral perivascular oedema. Clinicopathological findings which were comparable with those observed in Trema micrantha poisoned ruminants, associated with epidemiological evidence suggested the diagnosi...
Gard GP, Marshall ID, Walker KH, Acland HM, Saren WG.An outbreak of Murray Valley encephalitis (MVE) occurred in New South Wales during the first five months of 1974. Specimens from 52 horses with nervous disease collected January to May 1974 were examined histopathological or virologically. Although MVE virus was not isolated, 13 horses had serological evidence of recent infection with MVE virus. Another 4 horses had evidence of recent infection with Ross River virus. Two animals had histological evidence of viral infection of the central nervous system. Attempts to experimentally infect 2 horses with a low dose of MVE virus were not successful...
The proposed biological mechanisms for exercise-induced pulmonary haemorrhage (EIPH) are many and varied. Better knowledge of risk factors should lead to achievable measures to reduce the incidence. Objective: To identify risk factors associated with epistaxis following racing in UK Thoroughbreds, to gain possible insights into the pathogenesis of the condition and to investigate the association between epistaxis and race finishing position. Methods: The association of epistaxis occurring on UK racecourses between 1996 and 1998 with a wide range of race-, horse- and start-level variables was e...
Jindra C, Hainisch EK, Brandt S.Horses and other equid species are frequently affected by bovine papillomavirus type 1 and/or 2 (BPV1, BPV2)-induced skin tumors termed sarcoids. Although sarcoids do not metastasize, they constitute a serious health problem due to their BPV1/2-mediated resistance to treatment and propensity to recrudesce in a more severe, multiple form following accidental or iatrogenic trauma. This review provides an overview on BPV1/2 infection and associated immune escape in the equid host and presents early and recent immunotherapeutic approaches in sarcoid management.
Teifke JP, Weiss E.Unfixed and formalin-fixed frozen sections and paraffin-sections of histopathologically confirmed sarcoids of 20 horses were studied in the PCR. The used set of primers was located in the E5 open reading frame fitting both to bovine papillomavirus 1 (BPV-1) and BPV-2. Independent of the quality of the used tissues BPV-DNA was detected in all 20 sarcoids. By cleaving with restriction endonuclease Bst XI it was shown that the DNA-sequences amplified by PCR were identical with that of BPV-1. The results support the general view that BPV play an important role in equine sarcoids.
Erdemsurakh O, Ochirbat K, Gombosuren U, Tserendorj B, Purevdorj B, Vanaabaatar B, Aoshima K, Kobayashi A, Kimura T.Glanders is a contagious and fatal equine disease caused by the gram-negative bacterium Burkholderia mallei. B. mallei is prevalent among horse populations in Asia, the Middle East, and South America. More than four million horses have been registered in Mongolia in 2020. However, the recent prevalence of glanders has not been well investigated. In this study, we aimed to investigate the seropositivity of B. mallei in horse populations in Mongolia using the complement fixation test (CFT) and Rose Bengal plate agglutination test (RBT). We randomly collected blood samples from horses in central ...
Falcão MVD, Silveira PPM, Santana VLA, da Rocha LO, Chaves KP, Mota RA.Burkholderia (B.) mallei is the causative agent of glanders in Equidae. This study describes the first record of the Turkey 10 strain of B. mallei in glanderous horses in Northeastern of Brazil. This description should contribute to the future actions of diagnosis, control, and eradication of this disease in Brazil.
Kilcoyne I, Magdesian KG, Guerra M, Dechant JE, Spier SJ, Kass PH.Gastrointestinal disease has been associated with shedding of Salmonella with previous studies demonstrating that horses with colic have a higher risk of acquiring and shedding Salmonella organisms. Objective: The purpose of this study was to determine the prevalence of and risk factors associated with Salmonella shedding in a colic population at a referral clinic. Methods: Retrospective case-control study. Methods: For each colic case that was positive for Salmonella (n = 56), two colic cases (n = 112) that tested negative for Salmonella, were enrolled as controls. Associations between va...
Bedenice D, Johnson AL.EPM, CVSM, and EDM are currently recognized as the 3 most common neurologic diseases in US horses, with the latter 2 conditions being most prevalent in young animals. Moreover, horses competing at shows and performance events are at greater risk for exposure to highly contagious, neurologic EHV-1 outbreaks. A clinical diagnosis of any neurologic disease should be based on a careful history, complete neurologic examination, and appropriate diagnostic testing and interpretation. However, mild or early neurologic signs can often mimic or be mistaken for an orthopedic condition when horses present...
Price D, Barnum S, Mize J, Pusterla N.The purpose of this study was to explore sampling options for a reliable and logistically more feasible protocol during a large EHV-1 outbreak. Seventeen horses with clinical infection as well as nineteen healthy herdmates, all part of an EHM outbreak, were enrolled in the study. Each horse was sampled two-four times at intervals of 2-6 days during the outbreak. All samples were collected using 6'' rayon-tipped swabs. Nasal secretions were used as the diagnostic sample of choice. Additional samples, including swabs from the muzzle/nares, swabs from the front limbs, rectal swabs, swabs of the f...
Aronson H, Tough SC.People use horses for work and recreational purposes on farms and ranches in Alberta, Canada. This retrospective descriptive review examines the records of all those people killed while around horses between 1975 and 1990. The intent is to ascertain features common to these injuries and to suggest prevention strategies. Records from the Office of the Chief Medical Examiner of Alberta revealed that 38 people were involved in horse-related fatalities between 1975 and 1990 and that 22 died of head injuries. All 38 deaths were classified as accidental. Some of these might have been prevented, or i...
Rushton JO, Kolodziejek J, Nell B, Nowotny N.The aim of this study was to assess the extent of asinine herpesvirus (AsHV) type 5 infection in 'closed' populations of clinically normal Lipizzaner horses. Peripheral blood mononuclear cells plus nasal and conjunctival swabs were obtained on four occasions over an 18 month period from 266 animals as part of a health surveillance programme. Sequence analysis of samples that were positive by nested consensus herpesvirus PCR but negative using quantified equid herpesvirus (EHV) type 2 and 5 PCR, revealed a total of 51 samples from 39 horses positive for AsHV-5. No statistically significant asso...
Campbell GL, Reeves WC, Hardy JL, Eldridge BF.Neutralization tests were done on sera from 141 horses from high elevation regions of California. Antibody prevalences to Jamestown Canyon, snowshoe hare, and California encephalitis viruses in the California serogroup and Northway virus in the Bunyamwera serogroup were 55%, 43%, 18%, and 46%, respectively. In 51 horses from rural low elevation regions, seroprevalences were 31%, 35%, 35%, and 37%, respectively. Twenty-four horses from a suburban lowland area were seronegative, except for a single horse with a low titer to snowshoe hare virus. Seroprevalence to Jamestown Canyon and snowshoe har...
Wittwer C, Hamann H, Rosenberger E, Distl O.This study aimed to quantify the factors associated with the prevalence of the radiological signs of osteochondrosis (OC) and osteochondrosis dissecans (OCD) in South German Coldblood (SGC) horses. The prevalence of OC and OCD in fetlock and hock joints was analysed in 167 young coldblood horses with a mean age of 14 months. The presence of at least one osteochondrotic lesion (OC) in fetlock or hock joints was documented for 61.7% of the horses and 26.9% of the horses had osseus fragments. Osteochondrotic findings at the dorsal aspect of the sagittal ridge of the third metacarpal/metatarsal bo...
Murray JK, Singer ER, Morgan KL, Proudman CJ, French NP.Fatalities resulting from horse falls occurring during the cross-country phase of eventing competitions initiated epidemiological investigation of the risk factors associated with horse falls. Objective: To identify variables that increased or decreased the risk of a horse fall during the cross-country phase of an eventing competition. Methods: Data were collected from randomly selected British Eventing competitions held in Great Britain during 2001 and 2002. Data were obtained for 173 cases (jumping efforts resulting in a fall of the horse-and-rider partnership) and 503 matched controls (jump...