Diseased Horses Research Articles

Large-scale study of blood markers in equine atypical myopathy reveals subclinical poisoning and advances in diagnostic and prognostic criteria

Equine atypical myopathy (AM) is a severe rhabdomyolysis syndrome primarily caused by hypoglycin A (HGA) and methylenecyclopropylglycine protoxins. This study aimed to refine diagnostic and prognostic criteria for AM while exploring apparently healthy cograzers. Blood samples from 263 horses, including AM cases (n= 95), cograzers (n= 73), colic horses (n= 19), and controls (n= 76), were analyzed for HGA, its toxic metabolite, and acylcarnitines profile. Diseased horses exhibited alterations in acylcarnitines that strongly distinguished them from controls and colic horses. Regression analyses identified distinct acylcarnitines profiles among groups, with cograzers showing intermediate alterations. Age and gelding status emerged as protective factors against AM. Furthermore, serum acylcarnitines profiling was valuable in predicting AM survival, with isovaleryl-/2-methylbutyrylcarnitine (i.e., C5 acylcarnitine) showing promise as both a diagnostic and prognostic marker. Subclinical alterations in cograzers underscore a novel aspect: the presence of subclinical cases of AM.

Unveiling genome plasticity and a novel phage in Mycoplasma felis: Genomic investigations of four feline isolates.

Mycoplasma felis has been isolated from diseased cats and horses, but to date only a single fully assembled genome of this species, of an isolate from a horse, has been characterized. This study aimed to characterize and compare the completely assembled genomes of four clinical isolates of M. felis from three domestic cats, assembled with the aid of short- and long-read sequencing methods. The completed genomes encoded a median of 759 ORFs (range 743-777) and had a median average nucleotide identity of 98.2 % with the genome of the available equid origin reference strain. Comparative genomic analysis revealed the occurrence of multiple horizontal gene transfer events and significant genome reassortment. This had resulted in the acquisition or loss of numerous genes within the Australian felid isolate genomes, encoding putative proteins involved in DNA transfer, metabolism, DNA replication, host cell interaction and restriction modification systems. Additionally, a novel mycoplasma phage was detected in one Australian felid M. felis isolate by genomic analysis and visualized using cryo-transmission electron microscopy. This study has highlighted the complex genomic dynamics in different host environments. Furthermore, the sequences obtained in this work will enable the development of new diagnostic tools, and identification of future infection control and treatment options for the respiratory disease complex in cats.

Unveiling Differential Responses of Granulocytes to Distinct Immunostimulants with Implications in Autoimmune Uveitis.

The perception of circulating granulocytes as cells with a predetermined immune response mainly triggered by pathogens is evolving, recognizing their functional heterogeneity and adaptability, particularly within the neutrophil subset. The involvement of these cells in the pathophysiology of autoimmune uveitis has become increasingly clear, yet their exact role remains elusive. We used an equine model for autoimmune-mediated recurrent pan-uveitis to investigate early responses of granulocytes in different inflammatory environments. For this purpose, we performed differential proteomics on granulocytes from healthy and diseased horses stimulated with IL8, LPS, or PMA. Compared to healthy horses, granulocytes from the recurrent uveitis model significantly changed the cellular abundance of 384 proteins, with a considerable number of specific changes for each stimulant. To gain more insight into the functional impact of these stimulant-specific proteome changes in ERU pathogenesis, we used Ingenuity Pathway Analysis for pathway enrichment. This resulted in specific reaction patterns for each stimulant, with IL8 predominantly promoting Class I MHC-mediated antigen processing and presentation, LPS enhancing processes in phospholipid biosynthesis, and PMA, clearly inducing neutrophil degranulation. These findings shed light on the remarkably differentiated responses of neutrophils, offering valuable insights into their functional heterogeneity in a T-cell-driven disease. Raw data are available via ProteomeXchange with identifier PXD013648.

Effect of Exercise on Biochemical Factors in Healthy and Diseased Horses

Effect of Exercise on Biochemical Factors in Healthy and Diseased Horses

Direct and culture-enriched 16S rRNA sequencing of cecal content of healthy horses and horses with typhlocolitis.

Next generation sequencing has demonstrated that alpha diversity of the fecal microbiota is significantly altered in horses with typhlocolitis. The objective of this study was to evaluate the bacterial composition of the cecum content of horses with and without typhlocolitis through direct and culture-enriched 16S gene sequencing of six healthy horses and six horses with acute typhlocolitis; a case-control study design. Cecal content was collected after euthanasia. An aliquot was used for direct 16S gene sequencing. Another was serially diluted with brain heart infusion (BHI) and plated onto five different agar media. All culture medias, except for MacConkey, were incubated anaerobically. Bacterial colonies were harvested in bulk and used for DNA extraction, 16S PCR amplification, and sequenced using the Illumina MiSeq platform. Predominant phyla in healthy and diseased horses were Firmicutes, followed by Bacteroidetes in all cultured medias, except for MacConkey agar, in which Proteobacteria was the dominant phylum. Greater bacterial richness was identified in sequenced cecal contents as compared to cultured plates (P < 0.05). Culture-enriched molecular profiling combined with 16S rRNA gene sequencing offer an alternative method for the study of the gut microbiota of horses. For direct cecum content 16S gene amplification, the alpha diversity indices were lower in diarrheic horses compared to healthy horses (P < 0.05). A higher relative abundance of Fusobacteriota was found in 2/6 samples from diarrheic horses. The role of Fusobacteriota in equine colitis deserves investigation.

The hygienic aspects in the management of strangles

SummaryStreptococcus equi subsp. equi (S. equi) is a frequently encountered pathogen in equine practice. S. equi causes infection of the upper airways of horses, a condition known as strangles. Strangles is a highly contagious disease and may be economically devastating as well. Difficulties in the eradication of the disease using vaccines and medical treatments make hygienic measures crucial in order to limit transmission of the pathogen during outbreaks. This review aims to elucidate the challenges in handling an outbreak of strangles as well as develop a basic plan on how such an outbreak is handled in a hygienically optimal fashion. The results of this review suggest a longer environmental survival time of S. equi than previously assumed and support the importance of modification of surfaces for proper disinfection with appropriate disinfectants. Furthermore, the efficiency of using a colour‐coding system in dividing healthy, exposed and clinically affected horses is discussed. Individual temperature monitoring twice daily is recommended for the identification of diseased horses before they pose a contagious risk. Additionally, changing clothes between visiting different stable units is likewise recommended, to minimise transmission of disease. In conclusion, veterinarians, personnel and horse owners at equestrian centres need to be aware of the importance of isolation, monitoring and dividing the site into zones according to the risk of infection. Finally, it can be concluded that regardless of size, practical biosecurity measures can be implemented within all equine facilities.

Feasibility of a point-of-care ultrasound protocol for cardiorespiratory evaluation of horses in different clinical settings.

A point-of-care ultrasound (POCUS) protocol for evaluation of the cardiac and respiratory systems in horses does not exist. (a) Describe the windows of a POCUS protocol for cardiorespiratory assessment of horses (CRASH); (b) Estimate the number of acoustic windows that can be acquired by a sonographer-in-training; (c) Estimate the time required to complete the protocol for specific groups of horses; (d) Describe the sonographic abnormalities detected in horses presented with cardiovascular, respiratory, or systemic disease. Twenty-seven healthy horses, 14 horses competing in athletic events, and 120 horses with clinical disease. A pocket-sized ultrasound device was used to acquire 7 sonographic cardiorespiratory windows in various clinical scenarios. The duration of the examination was timed, and images were evaluated for diagnostic quality. Abnormalities in horses with clinical disease were determined by an expert sonographer. The CRASH protocol could be performed in healthy and diseased horses in hospital, barn, and competition settings between 5.5 ± 0.9 (athletic horses) and 6.9 ± 1.9min (horses with clinical disease). Thoracic windows were obtained most consistently, followed by right parasternal long-axis echocardiographic windows. Frequently detected abnormalities were pleural fluid, lung consolidation, B-lines, and moderate-to-severe left-sided heart disease. The CRASH protocol was feasible using a pocket-sized ultrasound device in various groups of horses, could be completed rapidly in a variety of settings, and frequently identified sonographic abnormalities when evaluated by an expert sonographer. The diagnostic accuracy, observer agreement, and utility of the CRASH protocol merit further evaluation.

Implication of Cellular Senescence in Osteoarthritis: A Study on Equine Synovial Fluid Mesenchymal Stromal Cells.

Osteoarthritis (OA) is described as a chronic degenerative disease characterized by the loss of articular cartilage. Senescence is a natural cellular response to stressors. Beneficial in certain conditions, the accumulation of senescent cells has been implicated in the pathophysiology of many diseases associated with aging. Recently, it has been demonstrated that mesenchymal stem/stromal cells isolated from OA patients contain many senescent cells that inhibit cartilage regeneration. However, the link between cellular senescence in MSCs and OA progression is still debated. In this study, we aim to characterize and compare synovial fluid MSCs (sf-MSCs), isolated from OA joints, with healthy sf-MSCs, investigating the senescence hallmarks and how this state could affect cartilage repair. Sf-MSCs were isolated from tibiotarsal joints of healthy and diseased horses with an established diagnosis of OA with an age ranging from 8 to 14 years. Cells were cultured in vitro and characterized for cell proliferation assay, cell cycle analysis, ROS detection assay, ultrastructure analysis, and the expression of senescent markers. To evaluate the influence of senescence on chondrogenic differentiation, OA sf-MSCs were stimulated in vitro for up to 21 days with chondrogenic factors, and the expression of chondrogenic markers was compared with healthy sf-MSCs. Our findings demonstrated the presence of senescent sf-MSCs in OA joints with impaired chondrogenic differentiation abilities, which could have a potential influence on OA progression.

Molecular Features and Antimicrobial Susceptibilities of Streptococcus equi ssp. equi Isolates from Strangles Cases in Indonesia

Strangles, caused by Streptococcus equi ssp. equi (S. equi equi), is a highly infectious and frequent disease of equines worldwide. No data are available regarding the molecular epidemiology of strangles in Indonesia. This study aimed to characterize S. equi equi isolates obtained from suspected strangles cases in Indonesia in 2018. Isolates originated from seven diseased horses on four different farms located in three provinces of Indonesia. Whole genome sequences of these isolates were determined and used for seM typing, multilocus sequence typing (MLST), and core genome MLS typing (cgMLST). Genomes were also screened for known antimicrobial resistance genes and genes encoding for the recombinant antigens used in the commercial Strangvac® subunit vaccine. All seven S. equi equi isolates from Indonesia belonged to ST179 and carried seM allele 166. Isolates differed from each other by only 2 to 14 cgSNPs and built an exclusive sub-cluster within the Bayesian Analysis of Population Structure (BAPS) cluster 2 (BAPS-2) of the S. equi equi cgMLST scheme. All isolates revealed predicted amino acid sequence identity to seven and high similarity to one of the eight antigen fragments contained in Strangvac®. Furthermore, all isolates were susceptible to beta-lactam antibiotics penicillin G, ampicillin, and ceftiofur. Our data suggest that the horses from this study were affected by strains of the same novel sublineage within globally distributed BAPS-2 of S. equi equi. Nevertheless, penicillin G can be used as a first-choice antibiotic against these strains and Strangvac® may also be protective against Indonesian strains.

Bacterial Burden in the Air of Indoor Riding Arenas

Airway diseases in horses are often multifactorial and have a strong environmental background because diseased horses react to inhaled agents. In this study, the air quality of closed riding arenas was analyzed monthly in four riding arenas over the course of one year with special emphasis on bacteriology. A standardized riding program with one horse was used to measure exposures to airborne bacteria. Air samples were taken from the heights of the riders’ and the horses’ breathing zone (2.5 m and 1.5 m, respectively) at four sampling points before and after the riding program. The bacterial loads in all four arenas significantly increased after the riding program. However, the results showed no differences between the breathing zones of the riders (2.5 m height) and those of the horses (1.5 m height). Gram-positive bacteria and especially Staphylococcus spp. occurred as the predominant aerobic mesophilic bacteria; 80% of the identified Staphylococci were Staphylococcus xylosus. The cultured samples from the ground of the arenas indicated that the ground was probably the main source of airborne Staphylococcus spp. during riding. The impact of an additional bacterial burden in riding halls on the health of riders and horses remains unknown; however, the air quality of riding arenas should be of special interest in future studies in terms of the high air consumption of horses during training periods.

Fecal Microbiota Comparison Between Healthy Teaching Horses and Client-Owned Horses

The objective of this study was to compare the fecal microbiota of two healthy teaching horse herds with that of client-owned horses from the same geographic areas. The fecal microbiota of client-owned horses from Ontario Canada (n = 15) and Florida, USA (n = 11) was compared with that teaching horses from the University of Guelph, Ontario, Canada (n = 10) and the University of Florida, Florida, USA (n = 15). The fecal microbiota was characterized by sequencing of bacterial DNA using the V4 hypervariable region of the 16S rRNA gene. The diversity (inverse Simpson index) of the fecal microbiota was significantly higher in teaching than client owned horses from the same geographical area (P < .05). The community membership (Jaccard Index) and structure (Yue and Clayton index) of teaching horses was also significantly different from that of client owned horses from the same geographical area (AMOVA P < .001). The bacterial membership and structure of the fecal microbiota of Ontario and Florida teaching horses were significantly different, while the bacterial membership, but not the structure of Ontario and Florida client owned horses was significantly different (AMOVA P < .001). In all four groups of healthy horses, Lachnospiraceae, Ruminococcaceae, Bacteroidales, Clostridiales, and Treponema were detected in high relative abundance. The fecal microbiota of healthy horses from teaching herds kept in the same environment with identical management practices differs significantly from that of horses housed in different facilities with dissimilar management practices. Our results suggest an effect of the environment and management practices on the gastrointestinal microbiota. Researchers should attempt to include healthy horses from the same farm with similar management as control groups when comparing with diseased horses.

Serosurveillance of equine coronavirus infection among Thoroughbreds in Japan.

Equine coronavirus (ECoV) causes fever, lethargy, anorexia and gastrointestinal signs in horses. There has been limited information about the prevalence and seasonality of ECoV among Thoroughbreds in Japan. To understand the epidemiology and to evaluate the potential risk of ECoV infection to the horse industry in Japan. Longitudinal. The virus-neutralisation (VN) test was performed using sera collected three times a year at 4months intervals from 161 yearlings and at 6-7months intervals from 181 active racehorses in Japan in 2017-2018, 2018-2019 and 2019-2020. VN titre ≥1:8 was defined as seropositive, and ≥4-fold increase in titres between paired sera was regarded as indicative of infection. The VN test showed that 44.1% (71/161) of yearlings were seropositive in August, when they first entered the yearling farm. The infection rate was significantly higher between August and December (60.9%, 98/161) than between December and the following April (5.6%, 9/161; p=0.002). Among the racehorses, it was significantly higher between November and the following May (15.5%, 28/181) than between the preceding April/May and November (0%; p=0.02). The morbidity rates during the estimated periods of viral exposure were 39.2% in the yearlings and 4% in the racehorses. No horses showed any severe clinical signs. Clinical records did not cover the period during horses' absence from the training centre. ECoV was substantially prevalent in Thoroughbred yearlings and racehorses in Japan, and there was a difference in epizootic pattern between these populations in terms of predominant periods of infection. ECoV infection was considered to be responsible for some of the pyretic cases in the yearlings. However, no diseased horses were severely affected in either population, suggesting that the potential risk of ECoV infection to the horse industry in Japan is low.

Potent monoclonal antibody–mediated neutralization of a divergent Hendra virus variant

Hendra virus (HeV) and Nipah virus (NiV) are deadly zoonotic Henipaviruses (HNVs) responsible for recurrent outbreaks in humans and domestic species of highly fatal (50 to 95%) disease. A HeV variant (HeV-g2) of unprecedented genetic divergence has been identified in two fatally diseased horses, and in two flying fox species in regions of Australia not previously considered at risk for HeV spillover. Given the HeV-g2 divergence from HeV while retaining equivalent pathogenicity and spillover potential, understanding receptor usage and antigenic properties is urgently required to guide One Health biosecurity. Here, we show that the HeV-g2 G glycoprotein shares a conserved receptor tropism with prototypic HeV and that a panel of monoclonal antibodies recognizing the G and F glycoproteins potently neutralizes HeV-g2– and HeV G/F–mediated entry into cells. We determined a crystal structure of the Fab fragment of the hAH1.3 antibody bound to the HeV G head domain, revealing an antigenic site associated with potent cross-neutralization of both HeV-g2 and HeV. Structure-guided formulation of a tetravalent monoclonal antibody (mAb) mixture, targeting four distinct G head antigenic sites, results in potent neutralization of HeV and HeV-g2 and delineates a path forward for implementing multivalent mAb combinations for postexposure treatment of HNV infections.

The Public Health Burden of Virulent Extended-Spectrum β-Lactamase-Producing Klebsiella pneumoniae Strains Isolated from Diseased Horses.

Background:Klebsiella pneumoniae has been associated with both nosocomial and community-acquired infections with mounting public health concern throughout the world. The purpose of this study was to investigate the burden of virulent extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae among diarrheic horses or those with respiratory illness to underscore the public health implication of such strains. Materials and Methods: Rectal and nasal swabs were gathered from 100 diseased horses (50 diarrheic and 50 with respiratory illness). The collected swabs were processed for isolation of ESBL-producing K. pneumoniae using a selective medium followed by phenotypic and molecular identification of the isolates. All ESBL-producing K. pneumoniae strains were investigated for six virulence genes (type 3 fimbrial adhesin [mrkD], enterobactin [entB], regulator of mucoid phenotype A [rmpA], Klebsiella ferric iron uptake [kfu], mucoviscosity-associated gene A [magA], and type 2 capsular polysaccharide [K2]). Results: Of the 100 examined animals, ESBL-producing K. pneumoniae was recovered from 13 (13%), with isolation rates in horses suffering from diarrhea and respiratory illness being 20% and 6%, respectively. Among the obtained isolates, bla TEM and bla SHV were found in all strains (100%) followed by bla CTX-M in 92.3%, while none of the isolates had bla OXA. In addition, 13 ESBL-producing K. pneumoniae strains exhibited a multidrug resistance (MDR) pattern. Regarding the occurrence of virulence genes among the isolates, mrkD (100%) and entB (100%) were the most predominant virulence genes followed by rmpA (76.9%) and kfu (46.2%). On the contrary, magA and K2 were negative in all ESBL-producing strains. Furthermore, this work provides four K. pneumoniae mrkD partial sequences that displayed high genetic relatedness with those obtained from human to clarify the public health burden of such isolates. Conclusion: The occurrence of virulent ESBL-producing K. pneumoniae among diseased horses highlights the potential role of this animal in the epidemiology of such virulent and antimicrobial-resistant strains, which may have great public health threat.

First detection of the occurrence and study of the genetic diversity of novel putative kirkoviruses in donkey in China.

The first representative of a seemingly novel virus family has been found during the metagenomic examination of a diseased and dead horse in the USA [Li et al. in J Gen Virol 96:2721-2733, 2015]. These authors have suggested the need for the establishment of a new family with the tentative name Kirkoviridae; however, the suggested name is not official yet. Soon after the discovery, similar, relatively large CRESS-DNA viruses have been detected in various animals in China and elsewhere. Besides the two main genes (rep and cap), characteristic for members of the family Circoviridae, the tentative kirkoviruses have considerably larger genomes of approximately 4000 nucleotides. Accordingly, these viruses possess three four additional ORFs coding for proteins of unknown function. This has been described previously. In the present manuscript, the authors report the sequence of kirkovirus-like viruses, detected by PCR in donkey excretes in China. From 73 samples, 8 were found positive. From three of these newly detected viruses, the full genomic sequence was determined, whereas from the other five only one gene, namely the replication-associated (Rep) protein was sequenced.

Ex Vivo and In Vitro Analysis Identify a Detrimental Impact of Neutrophil Extracellular Traps on Eye Structures in Equine Recurrent Uveitis.

Equine recurrent uveitis (ERU) is a common ocular disease of horses and described as a model for human autoimmune uveitis. This immune-mediated, inflammatory condition progressively destroys the eye, ultimately leading to blindness. Genetic and autoimmune factors, next to infections with Leptospira, are discussed as key factors in the pathogenesis. Furthermore, a release of neutrophil extracellular traps (NETs) by activated neutrophils is involved. NETs are composed of decondensed chromatin and proteins that can immobilize invading pathogens. However, if NETs accumulate, they can contribute to detrimental autoimmune processes. Thus, we aimed to investigate the impact of NETs in ERU patients. Therefore, we quantified several NET-markers (cell-free DNA, nucleosomes, citrullinated histone H3, histone-myeloperoxidase complexes, interleukin-17, equine cathelicidin 1 and DNase I activity) and NET-autoantibodies in sera and vitreous body fluids (VBF) of ERU-diseased horses and correlated the data with the disease status (signalment, ERU scores and Leptospira infection status). NET markers were detected to varying degrees in VBF of diseased horses, and partially correlated to disease severity and the presence of Leptospira spp. Cell-free DNA and nucleosomes as NET markers correlate with ERU severity in total and VBF scores, despite the presence of active DNases. Additionally, a significant correlation between fundus affection in the eye and NET autoantibodies was detectable. Therefore, we further investigated the influence of VBF samples from equine patients and isolated NETs on the blood-retina barrier in a cell culture model. VBF of diseased horses significantly induced cytotoxicity in retinal pigment epithelial cells. Moreover, partially digested NETs also resulted in cytotoxic effects. In the presence of lipopolysaccharide (LPS), the main component of the leptospiral surface, both undigested and completely digested NETs were cytotoxic. Correlations between the ERU-scores and Leptospira were also calculated. Detection of leptospiral DNA, and antibody titers of the serovar Grippotyphosa correlated with disease severity. In addition, a correlation between Leptospira and several NET markers was observed in VBF. Altogether, our findings suggest a positive correlation between NET markers with disease severity and involvement of Leptospira in the VBF of ERU-diseased horses, as well as a cytotoxic effect of NETs in eyes.

Hematological, Biochemical, and Skeletal Muscle Metabolic Responses to Exercise Related Myopathy in Endurance Horses

Equine exertional rhabdomyolysis (ER) is a well-recognized disease affecting racehorses therefore this study was performed to evaluate haemato-biochemical alterations in 20 adult Arabian horses after 120 km race with trial of treatment. Horses were classified into 2 main groups: the first group (n:5) included healthy control horses while the second group(n:15) included horses showed signs of distress, moderately depressed, muscle stiffness, shifting hind limb lameness, elevated respiratory rate, sweating, firm painful hindquarter muscles, myoglobinuria and reluctance to move that lasts for several hours after ending of race. Based on the history and the through clinical examination of diseased horses, they were tentatively diagnosed as suffering from ER syndrome. Whole blood and serum samples were collected from both healthy control horses and diseased ones before and after treatment. Hemogram of examined horses showed only significant increased PCV (%) values of diseased horses with more prominent thrombocytopenia but with treatment their values showed marked improvement, where other haematological parameters showed non-significant changes in both groups either before or after treatment. Serum analysis of ER affected horses showed a higher serum enzymatic activities of creatine phosphokinase (CK) and aspartate aminotransferase (AST) with significantly increased values of total proteins, albumin, globulins, total bilirubin, glucose, creatinine and potassium. But with effective treatment protocol, these higher values began to be improved towards normal values again. While non-significant changes were observed in serum levels of Gamma-glutamyl transpeptidase (GGT), calcium, sodium and blood urea nitrogen (BUN) in ER affected horses. Based on obtained results, ER has negative impact on haemato-biochemical biomarkers with remarkable serum elevation of skeletal muscular specific enzymes, as well as by paralytic myoglobinuria.

Clinical and pathological examination of mycotoxicosis as an associated risk factor for colic in equine

A retrospective cohort study was conducted on two Egyptian horse farms with most of horses were suffered from abdominal pain to describe the associations between the occurrence of mycotoxicosis and equine colic. The farms owner complain was an unexpected increase in number of colic cases and deaths among horses. The association between colic and risk factors (sex, type of food either dry or mixed with roughages and hematobiochemical parameters) was compared using independent sample T-test. The associations between possible prognostic indicators for colic caused by mycotoxicosis was estimated using logistic regression analysis model. The cumulative incidence, incidence rates for colic attacks, survival rate among diseased horses were additionally estimated. Our results showed that a total of 24 out of the 132 horses suffered from colic due to feeding of ration contaminated with high percent of mycotoxin including Aflatoxins, Ochratoxins and or fusarium mycotoxins. The total cumulative incidence of colic due to mycotoxicosis was 19.7%. The horses fed on dry rations had more chance of developing colic than horses fed on mixed rations (P < 0.05). The overall incidence rate of colic due to mycotoxicosis was estimated at 18 colic attack/1000 horse/month. The mortality rate of horses suffered from colic due to mycotoxicosis was estimated at 5.9% (5/85), while the case fatality rate was estimated at 25% (n = 5/20). Inconclusion, our results showed that mycotoxicosis are considered an important risks factor for colic cases development in equine practice.

Association of Equine Herpesvirus 5 with Mild Respiratory Disease in a Survey of EHV1, -2, -4 and -5 in 407 Australian Horses.

Equine herpesviruses (EHVs) are common respiratory pathogens in horses; whilst the alphaherpesviruses are better understood, the clinical importance of the gammaherpesviruses remains undetermined. This study aimed to determine the prevalence of, and any association between, equine respiratory herpesviruses EHV1, -2, -4 and -5 infection in horses with and without clinical signs of respiratory disease. Nasal swabs were collected from 407 horses in Victoria and included clinically normal horses that had been screened for regulatory purposes. Samples were collected from horses during Australia's equine influenza outbreak in 2007; however, horses in Victoria required testing for proof of freedom from EIV. All horses tested in Victoria were negative for EIV, hence archived swabs were available to screen for other pathogens such as EHVs. Quantitative PCR techniques were used to detect EHVs. Of the 407 horses sampled, 249 (61%) were clinically normal, 120 (29%) presented with clinical signs consistent with mild respiratory disease and 38 (9%) horses had an unknown clinical history. Of the three horses detected shedding EHV1, and the five shedding EHV4, only one was noted to have clinical signs referable to respiratory disease. The proportion of EHV5-infected horses in the diseased group (85/120, 70.8%) was significantly greater than those not showing signs of disease (137/249, 55%). The odds of EHV5-positive horses demonstrating clinical signs of respiratory disease were twice that of EHV5-negative horses (OR 1.98, 95% CI 1.25 to 3.16). No quantitative difference between mean loads of EHV shedding between diseased and non-diseased horses was detected. The clinical significance of respiratory gammaherpesvirus infections in horses remains to be determined; however, this survey adds to the mounting body of evidence associating EHV5 with equine respiratory disease.

Rethinking equine anaesthetic risk: Development of a novel Combined Horse Anaesthetic Risk Identification and Optimisation tool (CHARIOT)

SummaryThe most widely used method of assessing the physical status of humans presented for anaesthesia is the American Society of Anaesthesiologists Physical Status Classification System (ASA‐PS). The ASA‐PS has been applied to animals including horses, but its use is problematic. The authors virtually convened a group of internationally recognised equine veterinary anaesthesiologists with the goal of developing a risk assessment tool for the evaluation of healthy and diseased horses presented for anaesthesia. With this survey and analysis, the authors aim to develop a simple rubric system to assess equine anaesthetic risk that augments the ASA‐PS system. The goal is to identify both diseased and healthy horses at increased anaesthetic risk prior to induction of anaesthesia so that measures might be implemented to potentially reduce morbidity and mortality.