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.
Morgante O, Vance HN, Shemanchuk JA, Windsor R.The epizootic of equine encephalomyelitis in 1965 in Alberta was proved to be due to Western Encephalomyelitis virus infection by serological findings and virus isolations.Sixty-three horses of 88 tested, showed a diagnostic rise of CF antibodies to Western Encephalomyelitis virus. Western Encephalomyelitis virus was isolated from 5 brains of horses. Homologous antibodies were shown in 3 of these animals, the only ones from which blood specimens were received. For the first time virological evidence is given that Western Encephalomyelitis virus infection in horses is found in more areas of Alb...
Wittich CA, Ward MP, Fosgate GT, Srinivasan R.To determine whether West Nile virus (WNV) disease hyperendemic foci (hot spots) exist within the horse population in Texas and, if detected, to identify the locations. Methods: Reports of 1,907 horses with WNV disease in Texas from 2002 to 2004. Methods: Case data with spatial information from WNV epidemics occurring in 2002 (1,377 horses), 2003 (396 horses), and 2004 (134 horses) were analyzed by use of the spatial scan statistic (Poisson model) and kriging of empirical Bayes smoothed county attack rates to determine locations of horses with WNV disease in which affected horses were consiste...
Kosuge J, Goto Y, Shinjo T, Anzai T, Takatori K.Sixty-six new and used samples of horse bedding materials: 60 rice straws, 2 wheat straws, 2 timothy hays and 2 wood chips, were collected from horse breeding stables of 33 farms in Japan and examined for the presence of Emericella nidulans (E. nidulans; anam. Aspergillus nidulans). The incidence of E. nidulans in the bedding materials was 75.8% and there was no significant difference in detection of the fungus between the new and used materials (25 out of the 33 samples, respectively). The growth of E. nidulans isolated in sterilized rice straw culture was accelerated by the addition of water...
Zorigt T, Furuta Y, Simbotwe M, Ochi A, Tsujinouchi M, Shawa M, Shimizu T, Isoda N, Enkhtuya J, Higashi H.Anthrax is a zoonotic disease caused by the gram-positive spore-forming bacterium Bacillus anthracis. Detecting naturally acquired antibodies against anthrax sublethal exposure in animals is essential for anthrax surveillance and effective control measures. Serological assays based on protective antigen (PA) of B. anthracis are mainly used for anthrax surveillance and vaccine evaluation. Although the assay is reliable, it is challenging to distinguish the naturally acquired antibodies from vaccine-induced immunity in animals because PA is cross-reactive to both antibodies. Although additional ...
Proudman C, Pinchbeck G, Clegg P, French N.As in other competitive sports, the famous Grand National steeplechase, which is held at Aintree in the United Kingdom and is watched by 600 million people worldwide, sometimes results in injury. By analysing data from the past 15 Grand National races (consisting of 560 starts by horses), we are able to identify several factors that are significantly associated with failure to complete the race: no previous experience of the course and its unique obstacles, unfavourable ground conditions (too soft or too hard), a large number of runners, and the length of the odds ('starting price'). We also f...
Steinman A, Kachtan I, Levi O, Shpigel NY.Clostridium botulinum type C is prevalent in Israel and outbreaks recorded in many species, other than horses. Association between levels of anti-BoNT/C antibodies and equine grass sickness (EGS) have been demonstrated but seroprevalence of anti-BoNT/C antibodies in horses has not been reported nor has EGS been reported in Israel. Objective: To determine the seroprevalence of specific anti-BoNT/C antibodies in horses in Israel and to determine whether age, breed and gender, or geographical region of farms are potential risk factors for exposure to BoNT/C. Objective: Anti-BoNT/C antibodies are ...
Rivera-Velez A, Huber L, Sinha S, Cohen ND.Rhodococcus equi is a common cause of severe pneumonia in foals. Emergence of macrolide-resistant R. equi isolated from foals and their environment has been reported in the United States. A novel erm(51) gene was recently identified in R. equi in soil from horse farms in Kentucky. Our objective was to determine the effect of the erm(51) gene and associated rpoB mutation on the fitness of multidrug resistant-R. equi (MDR-R. equi) under different nutrient conditions. Bacterial growth curves were generated for 3 MDR-R. equi isolates and 3 wild-type (WTN) R. equi isolates recovered from environmen...
Polzer J, Slater MR.A case-control study was conducted at the Texas Veterinary Medical Center between January 1, 1986 and December 31, 1991. Logistic regression was used to assess age, breed, sex, and seasonality as risk factors for equine laminitis. There were 70 acute cases, 183 chronic cases, and 779 controls. No statistical association was found between age, breed, sex, or seasonality and the diagnosis of acute laminitis. For chronic cases, the estimated odds ratio was statistically significant for age (OR = 1.05, 95% CI (1.02, 1.08)) and for the diagnosis of laminitis in the third quarter of the year (OR = 2...
Ross WA, Kaneene JB, Caron JP, Gallagher KF, Gardiner JC.The objective of this study was to identify factors that may affect recovery from and duration of a case of lameness in a stratified random sample of Michigan horses. This was done using data from Phase-II of the Michigan equine monitoring system (MEMS Phase-II), the equine health-monitoring study [Kaneene et al., Prev. Vet. Med. 29 (1997b) 277-292; Ross and Kaneene, Prev. Vet. Med. 28 (1996a) 209-224; Ross and Kaneene, Prev. Vet. Med. 29 (1996b) 59-75; Ross et al., Am. J. Vet. Res. 59 (1997) 23-29]. In this study, statistical modelling was conducted to evaluate risk factors affecting recovery...
Drury M.Participants in the 1- and 2-day Tamworth Dressage Club (TDC) annual dressage championships arrived in Moonbi, New South Wales (NSW) as reports of the equine influenza outbreak surfaced on 25 August 2007. Three horses who had attended a competition in Maitland the weekend before had been showing flu-like symptoms and the next day the site was declared a suspect premise. On 27 August, infection was confirmed and the site was placed in total quarantine. Although most participants had travelled long distances to compete and did not have provisions for them or their horses, the quarantine was not ...
Nara PL, Krakowka S, Powers TE, Garg RC.Fourteen young outbred horses, divided into 2 groups on the basis of 18- or 24-hour skin-test reactions to Streptococcus equi, were inoculated nasopharyngeally with virulent S equi. Animals (n = 6, group I) with evidence of previous exposure to S equi (positive dermal response and existing serum antibodies), with one exception, developed minimal or no signs of disease after inoculation. In contrast, S equi skin-test negative and seronegative horses (n = 8, group II) developed predictable and severe clinical signs of infection after their inoculation, including shedding of the organism from nas...
Monzón CM.A direct agglutination test is described to diagnose 'Mal de Caderas' caused by Trypanosoma evansi. The antigen used was a suspension of trypsin-treated parasites stabilized with formalin. The test was evaluated in horses with both natural and experimental infections. Test sensitivity and specificity were 94 and 97%, respectively. Treatment of serum with 2-mercaptoethanol before testing permitted the differentiation of IgM and IgG antibodies, and possible differentiation of current infection from past exposure to the parasite. The antigen was stable over a 6-month evaluation period and also sh...
Rando A, Di Gregorio P, Masina P.Horse DNA samples digested with PstI and probed with the rabbit beta 1 globin gene show three phenotypes determined by one fragment of variable length (about 5.1 or 3.3 kb). Family data demonstrate that these fragments segregate as Mendelian alleles. The frequencies of the two alleles are 0.66 for the 3.3-kb fragment and 0.34 for the 5.1-kb one. Another polymorphism has been detected with BamHI. Again three phenotypes determined by two alleles (fragments of 7.5 and 3.8 kb) have been observed. Allelic frequencies of the 7.5- and 3.8-kb fragments are 0.24 and 0.76 respectively. The two polymorph...
Thein P, Brown K.Infections with EHV1 can lead to manifestation at the CNS of horses followed by encephalomyelitis and "equine stroke". Horse experiments could confirm the clinical picture and gave links to the potential pathogenesis of the disease. We also have been in the position to isolate and characterize an EHV4 virus out of the brain of a horse with CNS disorders. The two viruses carry different biological properties which obviously dominate the pathogenesis. These properties as well as experimental and field cases are described and different diagnostic tests are discussed.
Roe H, Macpherson M, Denagamage T, Hopper S, Woodie B, Embertson R.Mare and foal survival are increased with prompt dystocia management. Data regarding mortality outcomes in mares and foals, when mares are recumbent at admission for dystocia resolution, are scarce. Objective: To evaluate recumbency at hospital admission as a risk factor for survival of mares and foals following dystocia management. Subsequent mare fertility was also evaluated. Methods: Retrospective cohort. Methods: Data were obtained from medical records at Rood and Riddle Equine Hospital of mares with dystocia between 1995 and 2018. Mare signalment, ambulation status, survival data and foal...
Duncan KT, Sundstrom KD, Hunt D, Lineberry MW, Grant A, Little SE.Although ticks are known vectors of pathogens across a range of hosts, there is limited research on emerging tick-borne diseases of horses in the United States. Tick surveys from other regions suggest Rickettsia spp. and Ehrlichia spp. may be clinically relevant in horses. To better understand the transmission risk of these tick-borne rickettsial disease agents to horses, ticks were collected from horses in Oklahoma. Ticks for the current study (306 Amblyomma americanum, 20 Dermacentor albipictus, 19 D. variabilis, and 7 A. maculatum) were evaluated for Rickettsia spp. and Ehrlichia spp. using...
Steward SKT, Hassel DM, Martin H, Doddman C, Stewart A, Elzer EJ, Southwood LL.Duodenitis-proximal jejunitis (DPJ) is an idiopathic and potentially fatal disease of horses characterized by abdominal pain, proximal intestinal inflammation, and subsequent gastric and small intestinal fluid accumulation. Although this disease is known to be costly and life threatening in the equine industry, the severity of clinical signs can vary widely, and an exact etiology has yet to be elucidated. This study looked to identify differences in clinical parameters of horses with DPJ between geographic regions in an effort to corroborate anecdotal reports and support theories of differing ...
Atwill ER, Mohammed HO, Lopez JW.To determine whether mean annual frequency and destination of equine travel was associated with exposure to Ehrlichia risticii and whether these associations were modified by horses' place of residence. Methods: Cross-sectional study. Methods: 511 equine operations containing 2,587 horses were visited in New York state from a target population of 39,000 operations. Methods: Each horse was tested for serum antibodies against E risticii, using indirect fluorescent antibody. Information on the horse's travel history, farm's management practices, and surrounding ecology was obtained by personal in...
Cohen ND, Kahn SK, Cywes-Bentley C, Ramirez-Cortez S, Schuckert AE, Vinacur M, Bordin AI, Pier GB.Rhodococcus equi is a prevalent cause of pneumonia in foals worldwide. Our laboratory has demonstrated that vaccination against the surface polysaccharide β-1→6-poly-N-acetylglucosamine (PNAG) protects foals against intrabronchial infection with R. equi when challenged at age 28 days. However, it is important that the efficacy of this vaccine be evaluated in foals when they are infected at an earlier age, because foals are naturally exposed to virulent R. equi in their environment from birth and because susceptibility is inversely related to age in foals. Using a randomized, blind experim...
Molini U, Franzo G, Rautenbach I, Otto HV, Khaiseb S, Di Gennaro A, Ntahonshikira C, Baines I, Monaco F, Savini G, D'Alterio N.West Nile virus (WNV) is a vector-borne virus maintained in nature by a bird-mosquito cycle. However, it can occasionally and accidentally infect horses and human beings, leading to sometimes severe or even fatal outcomes in these species. Therefore, the monitoring of its circulation and disease occurrence is of relevance. Unfortunately, it is underdiagnosed or not diagnosed in several African counties, including Namibia, where no data is currently available for horses. In this study, 98 horses in three different stables in the Windhoek city area were investigated. They were found to have a se...
Hochart É, Fournier Y.Equestrian sports are widely practiced in Switzerland as hobbies. Horses are imposing and unpredictable. As a result, traumatisms associated with horseback riding are common and cause serious injuries. Cranial traumatisms are among the most frequently encountered injuries and are associated with high rates of hospitalization and mortality. Helmet use decreases the severity of intracranial lesions. Close contact with horses can lead to the development of infectious diseases and respiratory allergies. Although infrequent in Europe, these infections occur sporadically and should be known by gener...
Denyer MS, Crowther JR.Antigenic differences within equine-1 and equine-2 isolates of influenza were studied by haemagglutination inhibition tests, indirect ELISA and competition ELISA, using the same antisera. Better differentiation was obtained with the competition ELISA than with the other two tests. All three methods produced similar relationships within the equine-1 isolates but differed in their ability to differentiate the equine-2 isolates where the competition ELISA was superior and produced epidemiologically sensible results. In all three tests, post-infection ferret and horse sera were more useful in disc...
Kaps M, Curik I, Baban M.Heterogeneity of variance of growth traits over age is a common issue in estimating genetic parameters and is addressed in this study by selecting appropriate variance structure models for additive genetic and environmental variances. Modeling and partitioning those variances connected with analyzing small data sets were demonstrated on Lipizzan horses. The following traits were analyzed: withers height, chest girth, and cannon bone circumference. The measurements were taken at birth, and at approximately 6, 12, 24, and 36 mo of age of 660 Lipizzan horses born in Croatia between 1948 and 2000....
Rojas-Núñez I, Gomez AM, Palmer S, Mohammed HO.Neurofilaments are structural proteins that are concentrated in the body and axons of neurons. Damage to the neurons or axons as a result of trauma or infectious diseases leads to the release of neurofilaments into blood and cerebrospinal fluid (CSF). This case-control study was carried out to compare serum levels of phosphorylated neurofilament heavy chain (pNF-H) between clinically healthy Thoroughbred (TB) horses and TB horses that suffered catastrophic musculoskeletal injuries (cMSI), and to investigate the correlation between putative risk factors and serum concentrations of pNF-H in inju...
Khan A, Mushtaq MH, Ahmad MUD, Nazir J, Fatima Z, Khan A, Farooqi SH.EI in non-vaccinated population causes disruption and economic losses. To identify the risk factors associated with the EI epidemics in equids in Pakistan, a 1:1 matched case control study was conducted during 2015-2016. Including a total of 197 laboratory confirmed cases and negative controls, matched on the basis of geography, time of sampling, specie and age. A piloted questionnaire was used to collect data regarding risk factors associated with the occurrence of EI in face to face interviews. Conditional logistic regression was performed to analyze the data. A total of 16 out of 23 variabl...
Liu L, Castillo-Olivares J, Davis-Poynter NJ, Baule C, Xia H, Belák S.Samples from horses experimentally infected with the "large plaque variant (LP3A+)" of equine arteritis virus were analysed. These included 182 nasal swabs collected from day 1 to 14 post-infection (p.i.), and 21 virus isolates obtained from white blood cells of animals that showed a prolonged viraemia between days 30 to 72 p.i. In order to determine the genetic stability of the virus and particularly to characterise the genetic variants found during the prolonged viraemia, partial sequences of open reading frame 5 (ORF5) encoding glycoprotein 5 (GP5) were generated. Viruses with amino acid su...
Bertuglia A, Pagliara E, Manca F, Pozzolo P, Mannelli A.The objective of this study was to report recovery time, retirement rate, racing performance, and presence of compensation pattern after musculoskeletal injuries (MSIs) in Standardbred racehorses (STBRs). This is a retrospective single open-cohort study, enrolling 356 STBRs in training in a single racetrack. Musculoskeletal injury was defined as any training-related injury after which the horse did not train for at least 15 days. The first and second MSIs encountered during the horse's racing career were considered. Medical records, training logbooks, and racing data were reviewed to determin...
Munk Z, Dusek J.The fertility problems were studied in the herd of the English Thoroughbred horse on the Napajedla stud farm. Breeding records for the period from 1880 to 1972 were used as the starting data. The survey comprised 32 stallions. The relationship between fertility and the number of matings was calculated by the chi 2 quantity. The calculated values are highly variable. However, it is generally seen in most of the stallions that the number of matings per heat (i. e. one or several matings) had no significant influence on the pregnancy of mares and on the fertility values of the stallions. A higher...
Eysker M, Vercruysse J.The epidemiology, chemotherapy and control of strongylus infections in the horse are discussed. The annual cycle of various species are stated. In addition the anthelmintics available for treatment and control and the occurrence of anthelmintic resistance are referred to. Finally the options for control under various management conditions (little if any grazing; extensive grazing; intensive grazing) are discussed.
Chatfield JA, Dewell R, Miranda AJ, Wilcox S, Vannieuwenhoven TJ.To describe on-site veterinary medical care for working dogs and horses deployed for the 2012 Republican National Convention (RNC) in Tampa, Fla, August 24 to 30, 2012. Methods: Retrospective case series. Methods: 130 dogs and 45 horses. Methods: Data collected included breed, age, history, task assignment, reason for evaluation, and physical examination findings. A patient encounter report was recorded each time an animal was seen by veterinary staff for a physical evaluation. Results: 46 of the 130 (35%) dogs and all 45 (100%) horses underwent at least 1 on-site veterinary evaluation, for a ...
Atwill ER, Mohammed HO, Lopez JW, McCulloch CE, Dubovi EJ.To locate counties within New York state with a high seroprevalence among the equine population, to determine host, management, and environmental factors that were associated with seropositivity to Ehrlichia risticii, and to determine evidence for arthropod- or helminth-mediated transmission of E risticii to horses. Methods: Cross-sectional study. Methods: A random sample of 3,000 of the 39,000 equine operations in New York state was selected, and 2,587 horses from 511 operations were tested. Methods: Blood samples were collected from horses and tested for seropositivity, using the indirect fl...
