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.
Mellor PS.African horse sickness (AHS) virus causes a non-contagious, infectious, arthropod-borne disease of equines and is enzootic in sub-Saharan Africa. The major vectors are species of Culicoides but mosquitoes and ticks may be involved. Periodically the virus makes excursions beyond its enzootic zones but until recently has not been able to maintain itself outside these areas for more than 2-3 consecutive years. This is probably due to a number of factors including the absence of a long term vertebrate reservoir, the prevalence and seasonal incidence of the vectors and the efficiency of control mea...
Cohen ND, Neibergs HL, Wallis DE, Simpson RB, McGruder ED, Hargis BM.Members of the genus Salmonella were identified in feces from horses, using the polymerase chain reaction (PCR) and genus-specific oligonucleotide primers. Feces from healthy horses were determined to be culture-negative for Salmonella spp. Fecal samples were inoculated with known numbers of colony-forming units (CFU) of S anatum, S derby, S enteritidis, S heidelberg, S newport, and S typhimurium. The DNA was extracted from fecal samples and amplified by PCR, using genus-specific primers. Sensitivity of the assay extended to 10(3) CFU of Salmonella sp/g of feces; sensitivity of microbiologic c...
Slater JD, Borchers K, Thackray AM, Field HJ.Four specific pathogen-free ponies were infected intranasally with equine herpesvirus 1 (EHV-1) and two were similarly infected with an EHV-1 thymidine kinase deletion mutant. The primary infections were characterized by a transient fever accompanied by virus shedding into nasal mucus and viraemia. No virus was detected in clinical specimens after 15 days post-infection. Two months later a reactivation stimulus was administered to all six ponies and only the four that had been previously inoculated with wild-type EHV-1 shed virus into nasal mucus (for 10 days), proving the presence of a latent...
Boschwitz JS, Timoney JF.The antiphagocytic property of equine fibrinogen for Streptococcus equi subsp. equi strain CF32 was examined in vitro. The results of bactericidal assays demonstrated that the presence of fibrinogen enhanced the ability of overnight and early log-phase cultures of strain CF32 to resist killing by equine neutrophils by 12-fold and seven-fold, respectively (p > 0.01). In addition, fibrinogen-coated bacteria treated with fibrinogen specific F(ab')2 fragments were 32% more susceptible to killing by equine neutrophils after opsonization in serum (p > 0.05), indicating that specific epitopes o...
COllinson PN, O'Rielly JL, Ficorilli N, Studdert MJ.Ocular problems characterized by conjunctivitis, epiphora, and keratopathy were detected in 35 of 80 Thoroughbred weanling foals that also had respiratory disease. Ocular problems were determined to be caused by infection with equine herpesvirus type 2 (EHV-2) and were successfully treated with ophthalmic medication containing idoxuridine. Equine herpesvirus type 2 isolated from 3 of 5 foals from which samples were collected. The identity of the causative virus as EHV-2 was confirmed by use of electron microscopy, restriction endonuclease DNA fingerprinting, and Southern blot analysis.
Ferreira-Dias G, Nequin LG, King SS.Equine endometria representative of Kenney's categories I, II, and III were incubated in vitro with phosphate buffer, Streptococcus pneumoniae, or S zooepidemicus. Endometrial tissues from mares in estrus and diestrus were first categorized according to Kenney's classification, then were tested for adherence of S pneumoniae and S zooepidemicus to the epithelia. Bacteria were not observed when the endometrial tissue was incubated with phosphate buffer or S pneumoniae. There was no statistical difference in attachment of S zooepidemicus to endometrial tissue from mares in estrus or diestrus if e...
Johnson BJ, Stover SM, Daft BM, Kinde H, Read DH, Barr BC, Anderson M, Moore J, Woods L, Stoltz J.Necropsies were performed on 496 horses that had a fatal injury or illness at a California racetrack during the period February 20th 1990 to March 1st 1992. The primary cause of death was categorised by breed, activity at time of injury or illness and organ system affected. Most of the submissions were Thoroughbred horses (432) and Quarter Horses (46). Most of the injuries occurred while racing (42%) and in training sessions (39%); with fewer non-exercise (12%) and accident (7%) related injuries or illnesses. Musculoskeletal injuries accounted for 83% of the Thoroughbred and 80% of the Quarter...
Bloch N, Breen M, Spradbrow PB.Seventy six formalin-fixed paraffin-embedded sarcoids from 62 Australian horses, collected over a ten year period, were examined for the presence of genomic sequences from bovine papillomavirus 1 and 2 (BPV1, BPV2) with the polymerase chain reaction (PCR). Sequences that could be amplified by primers specific for BPV1 and BPV2 were present in 56 of the 76 sarcoids (73%). A restriction site present in BPV1 and absent from BPV2 was detected in 28 of 34 amplified products that were treated with endonuclease.
MacDonald DG, Morley PS, Bailey JV, Barber SM, Fretz PB.Post operative surgical wound infection rates were determined 452 cases of equine orthopaedic surgery performed at the Western College of Veterinary Medicine, Saskatoon, Saskatchewan, between January 1, 1981 and December 31, 1990. Only surgical procedures classified as clean or clean-contaminated by the National Research Council were included in this study. The overall post operative infection rate was 10.0% (45 of 452). Clean surgeries (n = 433) had an 8.1% infection rate while clean-contaminated surgeries (n = 19) had a 52.6% infection rate. Information collected from the medical records was...
Martinez-Torrecuadrada JL, Iwata H, Venteo A, Casal I, Roy P.African horsesickness virus (AHSV) is a gnat-transmitted member of the Orbivirus genus of the Reoviridae family. The virus has a genome of 10 double-stranded RNA species (L1-L3, M4-M6, S7-S10). The L2 and M6 genes of AHSV serotype 4 (AHSV-4) which encode the outer capsid proteins VP2 and VP5, respectively, were inserted into recombinant baculoviruses downstream of the baculovirus polyhedrin, or p10 promoters. Recombinant baculoviruses expressing VP2, VP5, or VP2 and VP5 proteins of AHSV-4 were isolated. The expressed AHSV proteins were similar in size and antigenic properties to those of viral...
Odendaal JS.A survey conducted in 1992, using a standardised, stratified sample was used to determine companion animal numbers in South Africa as a single geographical entity. The results indicated that there were 3.93 million dogs, 0.97 million cats, 0.98 million birds, 0.22 million other companion animals and 0.1 million horses in South African households. Thirty-seven per cent of households keeping companion animals, kept dogs; cats (13.4%); birds (4.8%); other companion animals (1.1%) and horses (2%). These results may provide information about possible markets in terms of numbers of species kept.
Adeyefa CA, Quayle K, McCauley JW.We describe a rapid method for genetic characterisation of influenza virus genes using reverse transcription and amplification by polymerase chain reaction (RT/PCR) of all virus segments simultaneously (multiplex RT/PCR) using primers based on the conserved terminal sequences. The product has been shown to be suitable for determination of partial nucleotide sequences which can be used to search nucleotide sequence databases and rapidly map the genetic origin of each segment. We illustrate the use of the method by analysing genetic reassortment in H7N7 equine influenza viruses.
Weiblen R, Rabuske M, Rebelatto MC, Nobre VM, Canabarro TF.We report an outbreak of abortion due to equine herpesvirus (EHV) in 5 mares between 9 and 11 months of gestation, from a herd of 22 Thoroughbred mares. Equine herpesvirus was isolated from extracts of the liver, spleen and thymus but not from the lungs of a 9-month fetus grown in Rabbit Kidney (RK13) cells. The virus was identified by electron microscopy, where virus particles could be seen in the nucleus of infected cells, and by the fluorescent antibody technique with polyclonal antibodies against the whole virus. Anamnesis, necropsy, histopathology, bacteriology, and virology data suggest ...
Siles-Lucas M, Felleisen R, Cuesta-Bandera C, Gottstein B, Eckert J.Swiss and Spanish isolates of Echinococcus granulosus were compared using different molecular biological techniques: Genomic DNAs isolated from parasites originating from various intermediate hosts were subjected to Southern hybridization with different probes, the same source of DNA was used for DNA amplification using the Random Amplified Polymorphic DNA (RAPD) technique. With both methods the various isolates (metacestodes) of E. granulosus exhibited characteristic banding patterns which allowed us to assign them to the following groups of homologous profiles: (a) isolates of horse and donk...
Jaspers U, Thiele D, Krauss H.A competitive ELISA system for the detection of antibodies against Coxiella (C.) burnetii in cattle, sheep, goats, horses and humans is described. The ELISA is based on a biotinylated monoclonal antibody with specificity for C. burnetii lipopolysaccharide in combination with streptavidin peroxidase. For evaluation and statistical analysis, 413 sera from cattle, sheep, goats, horses and humans were tested in parallel in the indirect immunofluorescence test (IFT). Furthermore, a total of 448 bovine and human sera were also tested with an indirect ELISA and 47 sheep sera were investigated using t...
Paweska JT, Gerdes T, Van Heerden J.Rabbit hyperimmune serum prepared against a donkey alphaherpesvirus isolate (M7/91), and against EHV-1 and EHV-4 was used to characterise the antigenic relationship between these 3 viruses. Serum from immunised rabbits was always more specific for homologous virus and showed different cross reactivity for heterologous virus. It was concluded that the immunologic relationship between the M7/91 isolate and EHV-1, was closer than that between this isolate and EHV-4. A serological survey of donkeys (n = 116) and horses (n = 57) revealed evidence of the presence of neutralising antibody to M7/91 in...
Lazary S, Marti E, Szalai G, Gaillard C, Gerber H.The equine leucocyte antigen (ELA) types and the clinical diagnosis for equine sarcoid and summer dermatitis were evaluated in 2026 horses representing five breeds. Data were analysed in unrelated animals and in family material. In the case of equine sarcoid, a strong association was observed between the ELA class II DW13 antigen and its effect on Swiss (cP < 0.001), French (cP < 0.0001) and Irish (cP < 0.01) Warmblood horses. The class I antigen A3 occurred more frequently in sarcoid-affected French horses (cP < 0.001). These results confirm our earlier findings (Gerber et al. 1988). Among Fr...
Norred WP, Voss KA.Fumonisins are secondary metabolites of Fusarium moniliforme , Fusarium proliferatum and several other Fusaria that commonly contaminate corn. Only recently discovered in 1988, these mycotoxins appear to be the causative agents of several toxicoses in animals that result from ingestion of moldy corn or corn-based feeds. The syndromes observed vary considerably among the different species affected and include brain lesions in equids, lung edema in swine, and nephrotoxicity, hepatotoxicity and hepatocellular carcinoma in laboratory rats. There is also evidence that suggests that F. moniliforme a...
Chirnside ED, Wearing CM, Binns MM, Mumford JA.cDNA copies of the M and N genes of equine arteritis virus (EAV) isolates were synthesized by reverse transcription followed by polymerase chain reaction amplification. The cDNA was subjected to a cycle sequencing strategy using Taq polymerase, and the nucleotide and derived amino acid sequences of 10 virus isolates were compared. The M and N genes of all isolates had the same initiation and termination sites as the prototype Bucyrus strain and the encoded proteins were conserved between viruses. Comparison of nucleotide sequence homologies and phylogenetic tree analysis implied the existence ...
Fukunaga Y, Matsumura T, Sugiura T, Wada R, Imagawa H, Kanemaru T, Kamada M.Serum cross neutralisation tests were conducted with a recent American isolate (84KY-A1) and a European isolate, (Wroclaw-2) and compared with the prototype and modified viruses of the Bucyrus strain of equine arteritis virus by using virus specific immune horse sera. The modified Bucyrus strain was neutralised and showed high neutralisation titres with all the immune sera. The prototype Bucyrus strain was also substantially neutralised, followed by the 84KY-A1 strain. As a result of the tests with the modified Bucyrus strain as the antigen, 20 seropositive horses were discovered among home-br...
Ward NI, Savage JM.The elemental (Br, Cd, Cr, Cu, Mn, Ni, Pb, Se, V, and Zn) content of blood and wool or hair from animals (sheep, horses and alpacas) exposed to motor vehicle emissions alongside the London Orbital (M25) motorway is reported. Elemental values were determined by inductively coupled plasma mass spectrometry (ICP-MS) quality control assessment using flameless atomic absorption spectroscopy (for Pb, correlation coefficients of whole blood r = +0.87, and hair r = +0.82), and replicate (n = 10) analysis of the international reference material IAEA A13 Animal Blood. For Pb very good agreement was obta...
Beard WL, Bramlage LR, Schneider RK, Embertson RM.Medical records for 64 Thoroughbred and 45 Standardbred horses with osteochondrosis dissecans (OCD) of the tarsocrural joint that were treated by means of arthroscopic removal of the fragments before 2 years of age and before beginning racing were reviewed. Lesion site was recorded for all horses. The other foals from the dams of these surgically treated horses (siblings) were identified from mare progeny records. Racing data, including number of starts and money won during the 2- and 3-year-old racing years were obtained from the Jockey Club and the United States Trotting Association for affe...
Fogarty U, del Piero F, Purnell RE, Mosurski KR.The intestinal tracts of 363 horses were examined after slaughter at a horse abattoir. The presence or absence of Anoplocephala perfoliata and the sites of attachment were recorded. A total of 51 per cent of the horses had A perfoliata attached to the mucosa of the ileocaecal junction and/or to the caecal mucosa; 5 per cent of the horses had A perfoliata attached only to the mucosa of the ileocaecal junction, 24 per cent had A perfoliata attached only to the caecal mucosa and 22 per cent of the horses had A perfoliata attached at both sites. The degree of infestation did not appear to be influ...
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...
Baldwin JL, Cooper WL, Vanderwall DK, Erb HN.Serum samples for determination of IgG concentration were obtained between postpartum hours 18 and 48 from 132 Standardbred foals. Results of the IgG assay were not known to farm personnel. None of the foals was given plasma IV for treatment of hypogammaglobulinemia. Foal health records were examined retrospectively to determine prevalence of infectious-type illness (foal treatment days [FTD]), prevalence of life-threatening infectious illness (foal treatment days-serious condition [FTD-SC]), and number of diseases (NOD) per foal. Values for FTD, FTD-SC, and NOD per foal were compiled for the ...
Martín-Cuervo M, Gracia-Calvo LA, Macías-García B, Ezquerra LJ, Barrera R.Systemic inflammatory response syndrome (SIRS) is a very common finding in critically ill patients. To accurately identify patients with SIRS and those who need intensive care, several markers have been evaluated, including cortisol, WBC or lactate. It is widely known that a stress leukogram includes eosinopenia as one of its main markers (neutrophilia, eosinopenia, lymphopenia and mild monocytes). It is known that cortisol concentration in plasma is the main stress biomarker and is strongly correlated with the severity of disease in horses. However, it is not possible to measure this paramete...
Mortola E, Miceli G, Alarcon L, Azcurra M, Larsen A.In newborn foals the absorption of colostrum immunoglobulins in the small intestine is maximal up to 8 hours after birth and then progressively decreases to become null after 24 hours post-partum. Thus, equine practitioners need a simple, quick, inexpensive and reliable field test to identify foals affected by failure of passive transfer rather than an accurate method yielding quantitative results within the whole range of immunoglobulin concentrations. Objective: As the validity of the immunocrit method to detect failure of passive transfer in foals had not been evaluated before, the object...
Yeruham I, Elad D, Egozi O.A retrospective study of an outbreak of dermatophilosis in a herd of 18 adult horses and 13 foals, in Israel, is presented. To the best of our knowledge this is the first time such an outbreak has been reported from a country in the Mediterranean climatic zone. This outbreak might be associated with exposure of the horses to water and humidity as a result of excessive rainfall in November 1994, as well as intensive washing of the horses and a long period spent by the animals in a marshy manege.
Gibson MJ, Legg KA, Gee EK, Rogers CW.In the 2019/20 Thoroughbred racing season, the paper-based reporting process of stipendiary steward reports was upgraded to an online system ('Infohorse database') to allow for the rapid entry of precise event and injury data. The objectives of this study were to describe the incident and non-incident examinations during the 2019/20, 2020/21, and 2021/22 Thoroughbred flat racing seasons in New Zealand and describe the primary injury and reporting outcomes. The introduction of the online system was associated with fewer miscoding events with horse identification (0.1%). An improvement in the de...
Vatistas NJ, Meagher DM, Gillis CL, Neves JW.Twenty-two horses were examined because of firearm injuries. Nine had been shot with .22-caliber bullets, 2 with BB pellets, 6 with buckshot, 1 with a .35-caliber bullet, and 1 with an airgun pellet. Injury was confined to the skin or skeletal muscles in 8 horses. Of these, 7 returned to their previous use. In 14 horses, injuries to additional structures were incurred, including the sinus and pharynx (n = 2), mandible (n = 1), tooth (n = 1), aorta (n = 1), eye (n = 3), tibia (n = 1), gastrointestinal tract (n = 3), joint (n = 1), and trachea (n = 1). The 3 horses that had only eye injuries wer...
Carter BT, Richardson MD.The aim of the study was to examine helmet use, incidence of injury, and patient outcomes in a rural cohort of equestrian accidents. Unassigned: EHR records of patients admitted to a Level II ACS trauma center in the North-west United States were reviewed for helmet use. Injuries were categorized according to International Classification of Diseases-9/10 code. Unassigned: Of 53 identified cases, helmets only reduced superficial injury (χ (1) = 4.837, = 0.028). Intracranial injury rates were not different between those with and without helmets ( > 0.05). Unassigned: In equine related injur...
Sinclair R, Mumford JA.An antigen capture enzyme-linked immunosorbent assay (ELISA) was developed for the detection of equine herpesvirus type-1 (EHV-1) antigens in nasal swab specimens. The test was designed as a solid phase, amplified sandwich assay in which an EHV-1 specific monoclonal antibody was used to capture virus antigen and polyclonal antisera used to detect antigen bound to the test plates. Eight monoclonal antibodies were tested for their ability to capture virus antigen and one was selected for routine use. The sensitivity and specificity of the ELISA was compared with that of virus isolation using swa...
Williamson CC, Stoltsz WH, Mattheus A, Schiele GJ.The complement fixation test (CFT), indirect fluorescent antibody test (IFAT), card agglutination test for trypanosomiasis (CATT) and enzyme-linked immunosorbent assay (ELISA) were compared in their application to the serological diagnosis of Trypanosoma equiperdum infection in 43 horses. The CFT remains a reliable test for dourine, especially in countries where other members of the subgenus Trypanozoon do not occur. The IFAT is a good 'back-up' test, but, requiring skilled operators it has the disadvantage of making it labour intensive, and interpretation of results subjective. This makes it ...
Szczerba-Turek A, Siemionek J, Bancerz-Kisiel A, Raś A, Szweda W.The aim of the study was to analyse a part of the sequence of the E5 gene of bovine papillomaviruses (BPV) associated with equine sarcoids in Polish horses. Samples of 40 skin lesions obtained from 29 horses were collected for molecular examination. The PCR amplicons of BPV DNA were detected in 38 specimens. After phylogenetic analysis 37 specimens were recognized as BPV-1 and one as BPV-2. Phylogenetic analysis has allowed the classification of the amplicons into two phylogenetic groups (A1,) and four separate isolates (2, 10, 16, 17).
Coultous RM, Raftery AG, Shiels BR, Sutton DGM, Weir W.Sarcocystis fayeri is a canine protozoan parasite with an equine intermediate host. Historically classified as an incidental pathogen, recent literature has described the toxic effects of Sarcocystis fayeri in human food poisoning, and highlighted potential involvement in equine neuromuscular disease. Until now, horses were believed to be the exclusive intermediate host. This study reports the first molecular confirmation of S. fayeri in a donkey, and gives rise to the consideration of donkeys being a potential reservoir for the parasite. This finding is of particular importance in understandi...
Cameron-Whytock HA, Parkin TDH, Hobbs SJ, Brigden CV, Bennet ED.Equestrian eventing is a dangerous Olympic sport, with 16 rider and 69 horse fatalities at competition in the last 10 years. Despite this, there is limited research that aims to improve safety within the sport. Objective: The purpose of this study was to identify risk factors for horse falls, which are the leading cause of rider fatality within the sport. Methods: Retrospective cohort study. Methods: Competition data between January 2005 and December 2015 were analysed. Descriptive statistics followed by univariable logistic regression to identify risk factors for inclusion in a multivariabl...