Equine Rhinitis A Virus Infection in Thoroughbred Racehorses-A Putative Role in Poor Performance?
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ABSTRACT:
SUBMITTER: Back H
PROVIDER: S-EPMC6848918 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Equine influenza (EI) outbreaks occurred on 19 premises in Ireland during 2014. Disease affected thoroughbred (TB) and non-TB horses/ponies on a variety of premises including four racing yards. Initial clinical signs presented on 16 premises within a two-month period. Extensive field investigations were undertaken, and the diagnostic effectiveness of a TaqMan RT-PCR assay was demonstrated in regularly-vaccinated and sub-clinically-affected horses. Epidemiological data and repeat clinical samples were collected from 305 horses, of which 40% were reported as clinically affected, 39% were identified as confirmed cases and 11% were sub-clinically affected. Multivariable analysis demonstrated a significant association between clinical signs and age, vaccination status and number of vaccine doses received. Vaccine breakdown was identified in 31% of horses with up to date vaccination records. This included 27 horses in four different racing yards. Genetic and antigenic analysis identified causal viruses as belonging to Clade 2 of the Florida sublineage (FCL2). At the time of this study, no commercially available EI vaccine in Ireland had been updated in line with World Organisation for Animal Health (OIE) recommendations to include a FCL2 virus. The findings of this study highlight the potential ease with which EI can spread among partially immune equine populations.
| S-EPMC6027538 | biostudies-literature
Project description:Training has a great impact on the physiology of an athlete and, like all stressful stimuli, can trigger an innate immune response and inflammation, which is part of a wider coping strategy of the host to restore homeostasis. The Thoroughbred racehorse is a valid animal model to investigate these changes thanks to its homogeneous training and highly selected genetic background. The aim of this study was to investigate modifications of the innate immune response and inflammation in young untrained Thoroughbred racehorses during the first training season through haematological and molecular investigations. Twenty-nine Thoroughbred racehorses were followed during their incremental 3-month sprint exercise schedule. Blood collection was performed at time 0 (T0; before starting the intense training period), 30 days after T0 (T30), and 90 days after T0 (T90). Haematological parameters (red and white blood cells, haemoglobin, and platelets) were evaluated and haematocrit (HCT), mean corpuscular haemoglobin concentration (MCHC), and red cells width distribution + standard deviation (RDW-SD) were calculated. Moreover, via RT-qPCR, we investigated the expression of, Interleukin 1? (IL-1?), Interleukin 4 (IL-4) Interleukin 6 (IL-6), Interleukin 2 (IL-2), Interleukin 3 (IL-3), Interleukin 5 (IL-5) Interleukin 8 (IL-8), Trasformig Growth Factor ? and ? (TGF-?), Tumor necrosis factor ? (TNF-?), and Interferon ? (IFN-?)genes. Main corpuscular volume (MCV) showed a significant (p = 0.008) increase at T90. Main corpuscular haemoglobin (MCH) and haemoglobin concentration (MCHC) values were significantly augmented at both T30 (p < 0.001) and T90 (p < 0.001). Basophils were significant increased at T30 (p = 0.02) and eosinophils were significantly increased at T90 (p = 0.03). Significant differences in gene expression were found for all the genes under study, with the exception of IFN-? and TNF-?. In particular, IL-2 (T30, p = 0.011; T90, p = 0.015), IL-4 (T30, p = 0.009; T90, p < 0.001), and IL-8 (T30, p < 0.001; T90, p < 0.001) genes were significantly upregulated at both T30 and T90 with respect to T0, TGF-? was intensely downregulated at T30 (p < 0.001), IL-5 gene expression was significantly decreased at T90 (p = 0.001), while IL-1? (p = 0.005) and IL-3 (p = 0.001) expression was strongly augmented at the same time. This study highlighted long-term adjustments of O2 transport capability that can be reasonably traced back to exercise adaptation. Moreover, the observed changes of granulocyte numbers and functions and inflammatory cytokine gene expression confirm a major role of the innate immune system in the response to the complex of stressful stimuli experienced during the training period.
| S-EPMC7600081 | biostudies-literature
Project description:The domestication process of plants and animals typically involves intense inbreeding and directional selection for various traits. Here, we genotyped 370 Japanese Thoroughbred horses using the recently developed 670k SNP array and performed various genome-wide analysis also using genotype data of other horse breeds. We identified a number of regions showing interesting patterns of polymorphisms. For instance, the region containing the MC1R locus associated with chestnut coat color may have been targeted by selection for a different mutation much earlier on than the recent selection for chestnut color. We also identified regions that show signatures of selection specific to Thoroughbreds. In addition, we found that intense inbreeding early in the history of the Thoroughbred breed and also before the formation of the breed has a significant impact on the genomic architecture of modern Thoroughbreds. Our study demonstrates that the horse 670k array can be utilized to gain important insight into the domestication process of horses and to understand the genetic basis of the phenotypic diversity in horses.
| S-EPMC6655603 | biostudies-literature
Project description:Laterality can be observed as side biases in locomotory behaviour which, in the horse, manifest inter alia as forelimb preferences, most notably in the gallop. The current study investigated possible leading-leg preferences at the population and individual level in Thoroughbred racehorses (n = 2095) making halt-to-gallop transitions. Videos of flat races in the UK (n = 350) were studied to record, for each horse, the lead-leg preference of the initial stride into gallop from the starting stalls. Races from clockwise (C) and anti-clockwise (AC) tracks were chosen alternately at random to ensure equal representation. Course direction, horse age and sex, position relative to the inside rail and finishing position were also noted. On C courses, the left/right ratio was 1.15, which represents a significant bias to the left (z = -2.29, p = 0.022), while on AC courses it was 0.92 (z = 0.51, p = 0.610). In both course directions, there was no significant difference between winning horses that led with the left leading leg versus the right (C courses, z = -1.32, p = 0.19 and AC courses, z = -0.74, p = 0.46). Of the 2,095 horses studied 51.26% led with their L fore and 48.74% with their R, with no statistically significant difference (z = -1.16, p = 0.25). Therefore, there was no evidence of a population level motor laterality. Additionally, 22 male and 22 female horses were randomly chosen for repeated measures of leading leg preference. A laterality index was calculated for each of the 44 horses studied using the repeated measures: 22 exhibited right laterality (of which two were statistically significant) and 21 exhibited left laterality (eight being statistically significant); one horse was ambilateral. Using these data, left lateralized horses were more strongly lateralized on an individual level than the right lateralized horses (t = 2.28, p = 0.03, DF = 34) and mares were more left lateralized than males (t = 2.4, p = 0.03, DF = 19).
| S-EPMC5993273 | biostudies-literature
Project description:Ontario's Alcohol and Gaming Commission records equine racing fatalities through its Equine Health Program. The present study examined all Thoroughbred fatalities from 2003 to 2015, inclusive, to identify associations. Official records and details of fatalities were combined in multivariable logistic regression modelling of 236,386 race work-events (433 fatalities), and 459,013 workout work-events (252 fatalities). Fatality rates were 2.94/1000 race starts (all fatalities) and 1.96/1000 (breakdowns only) with an overall rate of 2.61% or 26.1 fatalities/1000 horses. Comparison with published reports reveals rates to be high. Musculoskeletal injury was the predominant complaint and there was a high incidence of horses dying suddenly. Liability was high for young horses early in the season with a differential according to sex and whether a male horse was gelded. Horses undertaking repeated workouts had a higher liability and liability was higher in workouts for horses switching from dirt/synthetic to turf racing and for young horses in sprints. Race distance was not significant but high fatality rates in some large field, distance races combined with effects of age and workload identified groups at particular risk. As field size increased, fatality liability increased for early-finishing horses. Findings suggest jockey strategy could be an important factor influencing fatalities. Probability of fatality declined over the study period. Findings indicate that rapid accumulation of workload in animals early in their preparation is likely to be damaging. Fatality fell toward the end of a season and for horses with a long career history of successful performance; however, horses not exhibiting this robustness and staying power represent the population of greatest concern. Associations may be characterised as representing sources of stress, current or cumulative, and identifying at-risk animals on this basis may be as productive as targeting specific, discrete mechanisms suspected to contribute to individual fatalities.
| S-EPMC8532649 | biostudies-literature
Project description:An outbreak of Getah virus infection occurred among racehorses in Japan during September and October 2014. Of 49 febrile horses tested by reverse transcription PCR, 25 were positive for Getah virus. Viruses detected in 2014 were phylogenetically different from the virus isolated in Japan in 1978.
| S-EPMC4412242 | biostudies-literature
Project description:Cardiac arrhythmias resulting in sudden cardiac death (SCD) are an important cause of racehorse fatalities. The objective of this study was to determine risk factors for SCD in Thoroughbreds by evaluating a sample with a policy of mandatory post-mortem following racing or training fatalities. Risk factors were compared between case horses with SCD (n = 57) and control horses with other fatal injury (OFI, n = 188) by univariable and multivariable logistic regression. Survival in years for horses with SCD was compared to OFI using the Kaplan-Meier method with log rank test. The following variables were most important in the multiple logistic model: Horses with SCD were more likely to die during training than during racing, SCD (42/57, 74%) vs. OFI (82/188, 44%; odds ratio [OR], 95% confidence interval [CI], 2.5, 1.2-5.4; p = 0.01), had fewer lifetime starts, median (interquartile range [IQR]), SCD (3.0 [0.0-9.0]) vs. OFI (9.0 [0.0-22.8]; OR, 95% CI, 0.96, 0.9-1.0; p = 0.02 and were less likely to be entire (uncastrated) males, SCD 9/57 (16%) vs. OFI (46/188, 25%; OR, 95% CI, 0.47, 0.1-0.9; p = 0.03). Survival in years (median (IQR)) for horses with SCD was 3.6 (3.1-4.4), which was shorter than OFI (4.5 [3.1-6.0], hazard ratio, 95%CI, 1.6,1.2-2.3; p < 0.001). SCD occurs more commonly in training than racing, which suggests exercise intensity is less important in precipitating this fatality. In this study, SCD occurred early in the careers of affected horses.
| S-EPMC9137751 | biostudies-literature
Project description:BackgroundEquine influenza is an important cause of respiratory disease in equids. The causative virus; EIV, is highly variable and can evolve by accumulation of mutations, particularly in the haemagglutinin (HA) gene. Currently, H3N8 is the sole subtype circulating worldwide with Florida clade 1 (FC1) is most prevalent in the Americas and FC2 in Asia and Europe. In Egypt, EIV was detected in two occasions: subtype H7N7 in 1989 and subtype H3N8 (FC1) in 2008. No data is available on the circulation pattern of EIV during the last decade despite frequent observation of suspected cases.MethodsTwenty-two nasal swabs were collected from vaccinated and non-vaccinated horses showing respiratory signs suggestive of EIV infection in 2017-18. Three additional swabs were retrieved during a national race event in January 2018 from Arabian mares with high fever, gait stiffness and dry cough. Samples were screened by RT-qPCR and HA1 domain of the hemagglutinin gene was amplified and sequenced for sequence and phylogenetic analysis.ResultsRT-qPCR screening revealed that only the 3 samples from the race were positive with cycle thresholds ranging from 16 to 21 indicating high viral load. Isolation attempts in hen's eggs were unsuccessful. Sequence analysis of the HA1 domain gene has revealed two identical nucleotide sequences, while the third contained 3 synonymous mutations. Phylogenetic analysis clustered study sequences with recent FC2 sequences from Europe. Amino acid alignments revealed 14 and 13 amino acid differences in the study sequences compared to A/equine/Egypt/6066NANRU-VSVRI/08 (H3N8) and A/equine/Kentucky/1997 (H3N8), respectively, available as EIV vaccines in Egypt. Nine amino acids were different from A/equine/Richmond/1/2007 (H3N8), the recommended FC2 vaccine strain by the world organization of animal health expert surveillance panel (OIE-ESP), two of which were unique to the Egyptian sequences while the remaining 7 changes were shared with the FC2-144V subgroup detected in the United Kingdom from late 2015 to 2016.ConclusionsThe study represents the first reported detection of FC2-144V related EIV from Arabian mares in Egypt, and probably from the entire middle east region. The presented information about EIV epidemiology and spread may require reconsideration of the vaccine strains used in the national vaccination programs.
| S-EPMC9652821 | biostudies-literature
Project description:Effects of parental age on offspring viability have been reported in a wide range of species. However, to what extent parental age influences offspring traits beyond viability remains unclear. Moreover, previous research has primarily focused on maternal age effects. The purpose of this study was to test for paternal and maternal age effects on offspring speed in thoroughbred racehorses. We analysed over 900 000 race performances by over 100 000 horses on British racecourses between 1996 and 2019. With knowledge of the age of all 41 107 dams and 2 887 sires at offspring conception, we jointly modelled maternal and paternal age effects using a 'within-individual centring' approach. Within-parents, we identified a significant effect of maternal age on offspring speed of -0.017 yards s-1 yr-1 and a corresponding paternal age effect of -0.011 yards s-1 yr-1. Although maternal age effects were stronger (more negative), the existence and magnitude of paternal effects is particularly noteworthy, given thoroughbred sires have no involvement in parental care. Our results also suggest that the selective disappearance of both sires and dams is ongoing. These findings could potentially be used to optimize thoroughbred racehorse breeding decisions, and more generally, add to the increasing body of evidence that both maternal and paternal age affect a range of offspring characteristics.
| S-EPMC9532991 | biostudies-literature
Project description:In Ireland, horses may be protected against equine influenza virus (EIV) as a result of natural exposure or vaccination. Current mandatory vaccination programmes are targeted at highly mobile horses. A correlation between antibody levels as measured by single radial haemolysis (SRH) and protective immunity against EIV has been established.The objective of this study was to determine the susceptibility of selected populations of horses by quantifying their antibodies to EIV.Blood samples were collected from Thoroughbred weanlings, yearlings, racehorses and broodmares, teaser stallions and non-Thoroughbred horses. Antibodies against EIV H3N8 and H7N7 were measured by SRH.The order of susceptibility to Equine Influenza (EI) in the populations examined in Ireland was as follows: Thoroughbred weanlings > teasers > non-Thoroughbred horses and ponies > Thoroughbred yearlings > Thoroughbred horses in training > Thoroughbred broodmares. The H3N8 antibody levels of the weanlings, yearlings, broodmares and horses in training were similar to their H7N7 antibody levels, suggesting that their antibodies were primarily vaccinal in origin. The teasers and non-Thoroughbreds had higher H3N8 antibody levels than H7N7 antibody levels, suggesting that the majority of seropositive horses in these populations had been exposed to H3N8 by natural infection.Weanlings, teasers and non-Thoroughbred horses were identified as most susceptible to EIV. The results suggest that it would be advisable that weanlings are vaccinated prior to attendance at public sales, that teaser stallions are vaccinated prior to each breeding season and that mandatory vaccination be implemented for participation in non-Thoroughbred events.
| S-EPMC4634612 | biostudies-other