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.
Price J, Marques JM, Welsh EM, Waran NK.This preliminary study investigated the attitudes, and evaluated the current practice of a sample of the veterinary profession in the UK in relation to the management of pain in horses. In June 2001, a questionnaire was posted to 260 veterinarians in specialised equine practice, and 140 veterinarians in general practice with a significant equine caseload. There was a 25 per cent response rate to the questionnaire, which recorded information about the availability and prescription of analgesic drugs, the factors influencing the selection of analgesics and their administration, and estimates of ...
Turner M, McCrory P, Halley W.Professional horse racing is an exciting and demanding sport with high injury rates. Surprisingly few epidemiological studies have been published and no prospective studies have been reported. This paper reviews the literature and provides a detailed breakdown of injuries in Great Britain and the Republic of Ireland for 1992-2000. The introduction of protective equipment is discussed and evidence for its effectiveness put forward.
Vigre H, Chriél M, Hesselholt M, Falk-Rønne J, Kjaer Ersbøll A.A follow-up study focusing on health problems interfering with optimal training of Danish Standardbred trotters was conducted with the participation of seven professional trainers. Our aim was to estimate the incidence of health problems that cause interruptions of optimal training, and to identify associations between the hazard of lameness and selected risk factors. The study population was dynamic and contained data of 265 Standardbred trotters monitored during 5 months in 1997 and 1998. The horses were >or=2 years old. Optimal training was defined as when the horse followed scheduled tr...
Taouji S, Collobert C, Gicquel B, Sailleau C, Brisseau N, Moussu C, Breuil MF, Pronost S, Borchers K, Zientara S.Equine herpesviruses type 1 and 4 (EHV-1 and EHV-4) are ubiquitous in the equine population. One of their main properties is their ability to establish life-long latent infections in their hosts even in those with natural or vaccine-induced immunity. However, effect of vaccination status on prevalence and tissue tropism was not established. In this study, EHV-1 and EHV-4 were detected by polymerase chain reaction and by classical virus isolation from neural, epithelial and lymphoid tissues collected from unvaccinated (33) or vaccinated (23) horses. The percentage of EHV-1- and EHV-4-positive h...
Lian WC, Liau MY, Mao CL.Nervous disorders were found in two horses and verified as aseptic encephalitis by necropsy in the summer of 2000. To investigate agents that affected the horses, diagnostic procedures involving virus isolation, neutralization test and reverse transcription-polymerase chain reaction (RT-PCR) were performed. We intracranially inoculated litters of suckling mice with tissues suspected of containing aseptic encephalitis, including cerebrum, cerebellum, brain stem, thalamus, and cerebrospinal fluids; the mice were then observed for 14 days. Neutralizing antibodies against Japanese encephalitis (JE...
Storey ES, Gerding PA, Scherba G, Schaeffer DJ.To determine survival over time of infectious equine herpesvirus-4, feline herpesvirus-1, and feline calicivirus in three commercially available and commonly used ophthalmic solutions (eyewash, fluorescein, and proparacaine HCl). Methods: Viruses used in this study were originally isolated from eyes of animals referred to the University of Illinois. Equine herpesvirus-4 was propagated in MDBK cells and feline herpesvirus-1 and feline calicivirus in CRFK cells. Methods: After separately inoculating a designated solution with a specific titer of an individual virus, solutions were incubated per ...
Collobert-Laugier C, Hoste H, Sevin C, Dorchies P.Forty-two horses from Normandy (France) were examined post-mortem for small strongyle infections from October to March. In the positive horses, total worm numbers ranged from 234 to 90,247 (mean 11,297). Encysted larvae represented the major part of the total cyathostome burdens with a high percentage (83%) being early third stage larvae. They were mostly recovered from the caecum (48%) and ventral colon (40%) and were less present in the dorsal colon (12%). Adult cyathostomes were mainly located in the ventral colon (64%) and less frequently in the dorsal colon (27%) and caecum (9%). Twenty s...
Schmitt B.Vesicular stomatitis is an infrequent yet important vesicular disease of cattle, horses, and swine. Periodic outbreaks of this disease in the United States have caused economic losses in cattle herds because of decreased production, movement restrictions, and trade embargoes. Vesicular stomatitis causes clinical signs indistinguishable from those of foot-and-mouth disease. It is of utmost importance that appropriate samples are collected from clinical cases of vesicular disease in cattle and swine so a rapid laboratory diagnosis can be made.
Ryu SH, Bak UB, Kim JG, Yoon HJ, Seo HS, Kim JT, Park JY, Lee CW.A 7-year-old Thoroughbred horse was admitted to the Equine Hospital, Korea Racing Association with signs of colic. Based on the size of impactions, the clinical signs, the results of abdominal paracentesis and medical treatment, the prognosis was poor. The horse died 3 hours later following hopeless discharge. At necropsy, the caecum and large colon were fully filled with fecal contents and there was a rupture (10 cm in dia) in the latero- ventral caecum. The mucosa of the ileo-caecal and caeco- colic valves appeared to the hyperemic, edematous and ulcerous. There were many tapeworms in the af...
Wamsley HL, Alleman AR, Porter MB, Long MT.To evaluate CSF in horses with confirmed West Nile virus encephalomyelitis. Methods: Retrospective study. Methods: 30 horses. Methods: Results of CSF analyses from horses with acute neurologic signs attributed to West Nile virus infection that was confirmed by immunoglobulin M antibody capture ELISA were reviewed and analyzed. Results: Among 30 CSF samples, findings in 8 (27%) were within reference ranges and in 22 (73%) were abnormal. Among the 22 abnormal samples, mononuclear pleocytosis was found in 16 (73%) and high protein concentration with nucleated cell count within reference range was...
Giese M, Bahr U, Jakob NJ, Kehm R, Handermann M, Müller H, Vahlenkamp TH, Spiess C, Schneider TH, Schusse G, Darai G.Equine arteritis virus (EAV) is the causative agent of the equine viral arteritis. It is a small RNA virus with a linear, non-segmented plus RNA genome. EAV is a member of the Arteriviridae family that includes porcine reproductive and respiratory syndrome virus (PRSSV), simian haemorrhagic fever virus (SHFV) and lactate dehydrogenase virus (LDV). The viral transmission is via respiratory and reproductive routes. Clinical signs in horses vary, and severe infection can lead to abortions in pregnant mares or neonatal foal death. The aim of this study was to investigate the development of the imm...
Newton JR, Wood JL.In an epidemiological study of risk factors for exercise-induced pulmonary haemorrhage (EIPH) in young Thoroughbreds in the UK, in which 148 horses contributed 1614 horse-months of data, there were 64 (4%) episodes of endoscopically visible tracheal bleeding and 824 (51%) episodes of increased quantities of haemosiderophages in tracheal washes. There were increases in prevalence and risk of EIPH by both definitions with age from or = 4 years, season of sampling from winter (Nov-Jan) to autumn (Aug-Oct) and several different measures of airway inflammation, including tracheal mucus, neutrophil...
Birks EK, Shuler KM, Soma LR, Martin BB, Marconato L, Del Piero F, Teleis DC, Schar D, Hessinger AE, Uboh CE.The incidence and severity of exercise-induced pulmonary haemorrhage (EIPH) in the 2 most commonly raced horse breeds, Thoroughbreds (TB) and Standardbreds (STD), were studied, with particular interest in the possible influence of frusemide (F) and/or the breed (or running gait) on EIPH. The appearance of blood within the trachea was semi-quantified using a published 5-point system, with zero assigned when no blood was observed, and numbers 1-4 assigned with increasing amounts of blood. Considering each endoscopic examination as a separate event, approximately 75% of the postrace endoscopic ex...
Yasuda R, Kawano J, Matsuo E, Masuda T, Shimizu A, Anzai T, Hashikura S.The prevalence of staphylococci that harbor the mecA gene responsible for methicillin resistance was examined in healthy breeding mares. Staphylococci often cause diseases of horses such as metritis, keratitis, and abscess. Methicillin-resistant staphylococci would make antibiotic treatments ineffective, so it may be significant to know the distribution of mecA-harboring staphylococci in mares. Isolation of mecA-harboring staphylococci was achieved from nares and pasterns of 100 mares in Hokkaido, Japan. From 13% of the mares, mecA-harboring staphylococci, including 15 isolates of Staphylococc...
Rabuffo TS, Orsini JA, Sullivan E, Engiles J, Norman T, Boston R.To determine associations between age, sex, or medical treatment and prevalence and severity of gastric ulceration in Standardbred racehorses in training. Methods: Cross-sectional study. Methods: 224 Standardbred racehorses in training. Methods: Gastroscopy was performed on each horse, and mucosal ulceration was graded from 0 (normal mucosa, no lesions) to 3 (extensive, often coalescing, lesions with areas of deep ulceration). Associations between age, sex, or treatment and prevalence and severity of ulcers were evaluated. Results: Prevalence of gastric ulceration was 87%. Although there was l...
Pinchbeck GL, Clegg PD, Proudman CJ, Morgan KL, Wood JL, French NP.We identified risk factors associated with falling during steeplechase racing. We used retrospective data from all steeplechase runs on UK racecourses during 1999: 10,866 starts with 647 horse falls. The relationship between continuous variables and falling was assessed using generalised additive models (GAMs). Polynomial fits then were included in a multilevel, multivariable logistic-regression model. The number of runners had a linear, positive association with the risk of falling. The distance of the race had a non-linear relationship with the risk of falling; the risk steadily increased in...
Koehler K, Stechele M, Hetzel U, Domingo M, Schönian G, Zahner H, Burkhardt E.This report describes a case of cutaneous leishmaniosis in a horse in southern Germany. Diagnosis is based on histopathology, immunohistochemistry and electron microscopy. The protozoan was identified as Leishmania infantum via PCR and restriction fragment length polymorphism. The horse did not show specific Leishmania antibodies. The lesions healed completely within 6 months without any specific treatment. Since neither the infected horse nor its dam had ever left their rural area, autochthonous infection in Germany cannot be excluded. Factors possibly influencing the epidemiological situatio...
O'Meara B, Mulcahy G.We report the results of a survey to assess the attitudes of horse owners and managers of equine businesses in Ireland to the control of helminth parasites, and the extent to which veterinary practitioners are involved in providing advice on parasite control of horses. Replies to our questionnaire indicated that there is a high level of awareness on the need for helminth control, typically leading to several doses of anthelmintic being administered to each animal every year. While a majority of respondents (61%) were concerned about the issue of anthelmintic resistance, only a few were of the ...
McCluskey BJ, Mumford EL, Salman MD, Traub-Dargatz JJ.Approximately 20 sentinel premises in Colorado were visited quarterly during a 3-year prospective study to investigate the persistence of VS viruses in horses. A survey to assess management practices, health events, animal movements and environmental data was completed at each visit. Collection of serum samples and oral swabs along with a clinical examination of sentinel horses were performed at each visit. Serum samples were tested by 2 or more of 4 available serological tests. The data collected for two years (August 1998 to August 2000) are reported here. During this period there was seroco...
Melo e Silva SR, Vulcano LC.Collateral cartilage ossification of the distal phalanx in the Brazilian Jumper horse is a common finding. The objective of this study was to evaluate the prevalence and the degree of ossification of the collateral cartilages of the distal phalanx in Brazilian Jumper horses. In an analysis of 652 collateral cartilages from the front feet of 163 horses, 93% of these cartilages had collateral cartilage ossification (P < 0.005), and 7% of these cartilages did not have any type of ossification. In ossified cartilages, 86.4% had ossification beginning from the base, and 6.6% had a separate cente...
Dwivedi SK, Dey S.Fluoride possesses both essential and toxic potentials. A cross-sectional study recorded the fluoride concentrations in sera of thoroughbred horses 5y of age from 4 localities in India. A total of 628 serum samples of were analyzed for fluoride content using ion selective potentiometry. The mean serum fluoride was estimated as 0.018 +/- 0.002, 0.096 +/- 0.004, 0.16 +/- 0.008 and 0.32 +/- 0.02 ppm in horses from the eastern, central. western and southern parts of the country respectively. Although there were significant difference in fluoride concentration among horses from different zones, all...
Christensen H, Bisgaard M, Olsen JE.Members of Bisgaard taxon 11 have been isolated from horses. These bacteria are of importance in the veterinary clinic and also to the medical profession, since they may be isolated from infected wounds of humans bitten by horses. Six strains from different continents were identified as taxon 11, with 16S rRNA similarities between 98.0 and 99.7%. A single isolate that represented the so-called (+)L-arabinose-positive Actinobacillus equuli isolated from a diseased foal showed 99.9% 16S rRNA similarity to the type strain of A. equuli. DNA-DNA hybridizations showed that (+)L-arabinose-positive st...
Little D, Blikslager AT.Deal impaction is prevalent in the south-eastern USA, where feeding of Coastal Bermuda hay has been implicated as a risk factor. Alternatively, infection with the tapeworm Anoplocephala perfoliata has been identified as a risk factor for ileal impaction in the UK. We hypothesised that feeding Coastal Bermuda hay and failure to administer routinely an anthelmintic with efficacy against tapeworms would place horses at risk of developing ileal impaction in the USA. Seventy-eight horses, with surgically confirmed ileal impaction and 100 horses admitted for colic that did not have an ileal impactio...
French NP, Smith J, Edwards GB, Proudman CJ.The reason for undertaking this study was that postoperative complications of colic surgery lead to patient discomfort, prolonged hospitalisation and increased cost. Potential risk factors for the 6 most common postoperative complications (jugular thrombosis, ileus, re-laparotomy, wound suppuration, incisional herniation and colic) were evaluated using multivariable models. Jugular thrombosis was associated significantly with heart rate greater than 60 beats/min and with increased packed cell volume (PCV) at admission. The risk of postoperative ileus also increased with increasing PCV at admis...
Hillyer MH, Taylor FG, Proudman CJ, Edwards GB, Smith JE, French NP.A case control study was performed to identify risk factors for colic caused by simple colonic obstruction and distension (SCOD) in the horse. Case horses were recruited from 2 veterinary school clinics. Control horses were population based and matched by time of year. A number of risk factors were considered in the following areas: general carer and premises information; exercise information; husbandry information (housing- and pasture-related); feeding information; breeding information; behavioural information; travel information; preventive medicine information and previous medical informat...
Proudman CJ, Smith JE, Edwards GB, French NP.Postoperative complications and mortality can occur many weeks or months after colic surgery. We are interested in the long-term outcome of these cases. This study documents patterns of mortality and morbidity among 341 horses that recovered from colic surgery March 1998-August 2000. The progress of each horse was rigorously followed by periodic telephone and postal questionnaires. Event time data were recorded for each animal and a total of 321 horse years of survival, together with death from all causes, colic-related death and various postoperative complications. Postoperative survival (of ...
Zweygarth E, Lopez-Rebollar LM, Meyer P.Twenty blood samples of zebras (Equus zebra zebra) from the Karoo National Park and the Bontebok National Park in South Africa, all seropositive for Theileria equi, were subjected to in vitro culture to identify carrier animals and to isolate the parasites. Sixteen animals had a detectable parasitaemia in Giemsa-stained blood smears examined before culture initiation, the remaining four animals were identified as T. equi carriers by in vitro culture. Cultures were initiated either in an oxygen-reduced gas mixture or in a 5% CO2-in-air atmosphere. Out of the 20 blood samples, 12 cultures of T. ...
Waters AJ, Nicol CJ, French NP.Stereotypies are invariant and repetitive behaviour patterns that seemingly have no function, which tend to develop in captive animals faced with insoluble problems and may be indicative of reduced welfare. A 4 year prospective study of the factors influencing the development of stereotypic and redirected behaviours (abnormal behaviour) in a population of 225 young Thoroughbred and part-Thoroughbred horses was conducted between 1995 and 1999. Abnormal behaviour affected 34.7% of the population. Multivariable analysis showed that foals of low- or middle-ranking mares were less likely to develop...
Martens RJ, Cohen ND, Chaffin MK, Takai S, Doherty CL, Angulo AB, Edwards RE.To determine the sensitivity and specificity of 5 serologic assays used to diagnose Rhodococcus equi pneumonia in foals and to determine whether any of the assays could be used to identify affected foals prior to the onset of clinical signs or to differentiate between affected and unaffected foals when clinical signs first become apparent. Methods: Nested case-control study. Methods: 26 foals. Methods: Serum samples were obtained from all foals at 2, 4, and 6 or 7 weeks of age. Additional samples were obtained from affected foals at the time of diagnosis of R equi pneumonia and from age-matche...
Blickwede M, Dolz G, Herrero MV, Tomlinson SM, Salman M.Serum samples were collected from domestic horses in 4 different regions of Costa Rica to detect antibodies against vesicular stomatitis viruses, serotypes New Jersey (VSV-NJ) and Indiana (VSV-IN). A total of 214 samples were tested by the virus neutralization test. The sampling regions were identified as low North Pacific dry area (1), low Middle Atlantic humid area (2), low South Pacific humid area (3), and the highlands (4). In region 1, 97.1% of horses were positive for VSV-NJ and 16.5% were positive for VSV-IN. The mean antibody titer and its standard deviation after logarithmic transform...
Dups JN, Morton JM, Anthony ND, Dwyer JF.This report describes the clinical signs of equine influenza (EI) during an epidemic in a closed, predominantly immunologically naïve population of horses. It included 254 study horses, few of which exhibited all three signs of pyrexia, nasal discharge and cough simultaneously. We conclude that although the majority of affected horses exhibit temperature patterns resembling those most often described in the published literature, clinicians should be aware that other profiles are quite common.
Sergeant ES, Stone M, Moloney BJ, Arthur R.Simulation models were developed to quantify the likelihood of equine influenza virus infection entering pre-movement isolation, persisting through pre- and post-movement isolation periods without being detected by scheduled laboratory testing, and escaping to infect susceptible horses at a destination. The mean probability of escape ranged from 1 in 1,200,000 to 1 in 600,000 depending on lot size. For 95% of iterations the probability of escape was less than 1 in 200,000, regardless of lot size. For a large group of 600 horses processed as multiple separate lots, the mean probability of escap...
Courtney CH, Asquith RL.ALTHOUGH the seasonal transmission of equine cyathostomes is well documented in cool climates (Ogbourne 1978),
less is known about their transmission in warm climates.
Australian studies have suggested that these parasites do not
survive well during the long, hot summers of the humid
subtropics (English 1979a.b). Development of egg to third
stage larva (L3) was rapid during the summer but the
percentage of larvae that survived to ascend herbage was very
low. In contrast, larvae survived for longer periods during the
cooler months and the highest L3 populations were observed
during spr...
Kydd JH, Slater J, Osterrieder N, Antczak DF, Lunn DP.This report summarises the findings of the Second Havemeyer EHV-1 Workshop, which was held in Steamboat Springs, Colorado, USA in September 2008. A total of 38 delegates, consisting of veterinary clinicians and scientists from academia and industry participated in a series of sessions that focused on equine herpesvirus myeloencephalopathy (EHM). Each session consisted of a review, followed by short presentations on current research topics. The sessions included EHM epidemiology, in vivo and in vitro models for studying EHM, EHV-1 virulence determinants, real-time PCR diagnostics, antiviral med...
Salud publica de MexicoJune 26, 2007
Volume 49, Issue 3 210-217 doi: 10.1590/s0036-36342007000300006
Fernández-Salas I, de Lourdes Garza-Rodríguez M, Beaty BJ, Jiménez JR, Rivas-Estilla AM.To investigate the presence of WNV in birds, horses and humans in northeast Mexico. Methods: Serum samples from 33 birds, 24 horses and 237 humans were screened by ELISA for Anti-WNV antibodies. Human serum samples were also screened for WNV RNA using an RT-PCR assay. Results: Positive sera were found in three birds and 15 horses. Forty percent of the human serum samples were positive for IgG antibodies and 0% for IgM antibodies and viral RNA. Conclusions: The results of this study show that WNV is present in northeast Mexico and it is a new emergent infectious agent that represents a challeng...
Pringle J, Aspán A, Riihimäki M.The value of repeated nasopharyngeal lavage (NPL) to detect silent carriers of Streptococcus equi has not been investigated. Objective: Determine if results of serial testing for S. equi by NPL predicts subsequent true carrier status as determined by both NPL and guttural pouch lavage. Methods: An outbreak of strangles with 100% morbidity in 41 mature Icelandic horses was followed prospectively to investigate development of silent carriers. All were initially positive to S. equi on NPL. The farm was closed to horse movement during the entire study. Methods: Prospective observational study. Tes...
Carter SD, May C, Barnes A, Bennett D.Antibody levels (IgG and IgM) to Borrelia burgdorferi were measured in the sera and synovial fluids of UK horses. Western blotting against B. burgdorferi was also used on samples from seropositive horses. A low incidence of seropositivity was shown in horses from most parts of the UK. This increased in areas that have a high incidence of human and canine borreliosis (Norfolk and south coast). Leptospira infections of horses did not cause cross reactions in the B. burgdorferi ELISA. Most horses did not display clinical signs of Lyme disease. As with dogs and man, it is apparent that B. burgdorf...
Kaiser-Thom S, Hilty M, Ramseyer A, Epper P, Gerber V.Equine pastern dermatitis (EPD) is a multifactorial syndrome, with prolonged exposure to moisture assumed to be a predisposing or primary factor. Objective: To examine the course of EPD lesion severity, changes in bacterial skin microbiota, and the influence of meteorological factors. Methods: Prospective, longitudinal cohort study over a one-year period, with six Franches-Montagnes stallions, four affected by EPD and two unaffected, that were kept under the same conditions. Methods: Pasterns were scored for lesion severity and sampled once a month for 12 consecutive months. Lesion severity, t...