Disease etiology in horses refers to the study of the causes and development of diseases within equine populations. It encompasses various factors, including genetic predisposition, environmental influences, infectious agents, and nutritional imbalances, that contribute to the onset and progression of diseases in horses. Understanding disease etiology is essential for identifying risk factors and implementing preventative measures in equine health management. This topic includes research on pathogen-host interactions, the impact of management practices on disease incidence, and the role of genetic and environmental factors in disease susceptibility. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, contributing factors, and implications of disease etiology in horses.
Ellerbrock M, Wehrend A.In horses, birth is classified as dystocia when the process of parturition threatens to inflict damage onto the mare or the foal, when assistance is required to complete the process of parturition, or when there are temporal deviations in the physiological duration of the first and/or second parturition stages. In this, the duration of the second stage is an important indicator in identifying dystocia, as this phase is easily discernible by the mare's behavior. Equine dystocia is classified as an emergency with life-threatening consequences for mare and foal. A large degree of variation has be...
Sanz MG.Foals become infected shortly after birth; most develop subclinical pneumonia and 20% to 30% develop clinical pneumonia that requires treatment. It is now well established that the combination of screening programs based on thoracic ultrasonography and treatment of subclinical foals with antimicrobials has led to the development of resistant Rhodococcus equi strains. Thus, targeted treatment programs are needed. Administration of R equi-specific hyperimmune plasma shortly after birth is beneficial as foals develop less severe pneumonia but does not seem to prevent infection. This article provi...
Fisher M, Nebroski M, Davies J, Janzen E, Sullivan D, Lung O.The complete genome of a novel torque teno virus species (Torque teno equus virus 2 (TTEqV2) isolate Alberta/2018) was obtained by high-throughput sequencing (HTS) of nucleic acid extracted from the lung and liver tissue of a Quarter Horse gelding that died of nonsuppurative encephalitis in Alberta, Canada. The 2805 nucleotide circular genome is the first complete genome from the Mutorquevirus genus and has been approved as a new species by the International Committee on Taxonomy of Viruses. The genome contains several characteristic features of torque teno virus (TTV) genomes, including an OR...
Gharehaghajlou Y, Raidal SL, Freccero F, Padalino B.Transportation may lead to oxidative stress (OS) and gastric ulceration in horses, and optimal feed management before, or during, transportation is unclear. This study aimed to evaluate the effects of transportation after three different feeding strategies on OS and to explore possible associations between OS and equine gastric ulcer syndrome (EGUS). Twenty-six mares were transported by truck for 12 hours without food or water. Horses were randomly divided into 3 groups; (1) fed 1 hour before departure (BD), (2) fed 6 hours BD, (3) fed 12 hours BD. Clinical examinations and blood collections w...
Humblet MF, Saegerman C.The present paper proposes a tool to follow up the compliance of staff and students with biosecurity rules, as enforced in a veterinary faculty, i.e., animal clinics, teaching laboratories, dissection rooms, and educational pig herd and farm. Unassigned: Starting from a generic list of items gathered into several categories (personal dress and equipment, animal-related items, infrastructures, waste management, management of material/equipment and behavior), a checklist was created for each sector/activity mentioned above, based on the rules and procedures compiled in the Faculty biosecurity st...
Peng S, Dahlgren AR, Donnelly CG, Hales EN, Petersen JL, Bellone RR, Kalbfleisch T, Finno CJ.The genomic sequence of the horse has been available since 2009, providing critical resources for discovering important genomic variants regarding both animal health and population structures. However, to fully understand the functional implications of these variants, detailed annotation of the horse genome is required. Due to the limited availability of functional data for the equine genome, as well as the technical limitations of short-read RNA-seq, existing annotation of the equine genome contains limited information about important aspects of gene regulation, such as alternate isoforms and...
Burns TA, Watts MR, Belknap JK, van Eps AW.Supporting limb laminitis (SLL) is a complication of severe orthopedic disease in horses and is often life-limiting, yet the pathophysiology remains obscure. Objective: To investigate the role of digital lamellar inflammatory signaling in the pathophysiology of SLL using a model of unilateral weight bearing, hypothesizing that there would be evidence of lamellar inflammation in limbs subjected to the model. Methods: Thirteen healthy adult Standardbred horses were used for this study (11 geldings, 2 mares; mean age 6.5 ± 2.5 years; mean body weight 458.3 ± 32.8 kg). Methods: Randomized...
Carver C, Bruemmer J, Coleman S, Landolt G, Hess T.Laminitis associated with equine metabolic syndrome causes significant economic losses in the equine industry. Diets high in non-structural carbohydrates (NSC) have been linked to insulin resistance and laminitis in horses. Nutrigenomic studies analyzing the interaction of diets high in NSCs and gene expression regulating endogenous microRNAs (miRNA) are rare. This study's objectives were to determine whether miRNAs from dietary corn can be detected in equine serum and muscle and its impacts on endogenous miRNA. Twelve mares were blocked by age, body condition score, and weight and assigned to...
Acevedo HD, Hassebroek AM, Leventhal HR, Duhamel GE, Carvallo FR.A 17-y-old Rocky Mountain gelding was presented to the Virginia-Maryland Veterinary Teaching Hospital because of a 4-wk history of anorexia, weight loss, lethargy, and fever of unknown origin. Abdominal ultrasound revealed lymphadenomegaly of the abdominal and colonic lymph nodes, thickening of the wall of the large colon, and a mass associated with the large colon. The horse was euthanized given a poor prognosis. On autopsy, an ~20-cm diameter mass was found within the mesocolon between the right ventral and right dorsal colon. The mass had invaded through the colonic walls and formed a fistu...
Baker E, Geick A, Hines M, Gerhold R, Cordero-Aponte C.A 17-year-old female grade pony presented to University of Tennessee Veterinary Medical Center in May of 2021 for evaluation of multifocal, firm, sessile, circular lesions of various diameters on the ventrum and flank. The lesions had been present for two weeks at presentation. An excisional biopsy found numerous adult and larval rhabditid nematodes most consistent with Halicephalobus gingivalis. PCR targeting a portion of the large ribosomal subunit confirmed this diagnosis. The patient was treated with a high dose course of ivermectin followed by fenbendazole. The patient began showing neuro...
Paraschou G, Vogel PE, Lee AM, Trawford RF, Priestnall SL.Multisystemic eosinophilic epitheliotropic disease (MEED) is a rare condition of equids characterized by eosinophilic infiltration of multiple organs. Clinical signs are variable depending on the affected organs. The most common clinical signs include chronic weight loss, diarrhoea and exfoliative dermatitis. Respiratory distress and raised liver enzymes are less frequently seen. The cause is unknown and the pathogenesis is poorly understood. There are less than 50 reported cases of horses with MEED. We now document the lesions in three donkeys with fluctuating or chronic loss of weight, letha...
Runge KE, Bak M, Vestergaard A, Staerk-Østergaard J, Jacobsen S, Pihl TH.Predicting non-survival in horses with acute colitis improves early decision making. Therefore, this study aimed to determine the prognostic value of serum amyloid A (SAA) and other clinicopathological and clinical variables in adult horses with acute colitis. Clinical variables, SAA and other blood biomarkers, including plasma L-lactate (lactate), were assessed in 176 horses with acute colitis. A multivariate model for the prediction of non-survival was constructed. Icelandic horses were analysed separately. Admission SAA was similar in survivors (median 548 mg/L; range 0-5453 mg/L) and...
de Almeida Campos AC, Cicolo S, de Oliveira CM, Molina CV, Navas-Suárez PE, Dos Santos TP, da Silveira VB, Barbosa CM, Baccarin RYA, Durigon EL....No abstract available
Willette J, Gerras A, Sledge D, Koch D.A 13-year-old multiparous Quarter Horse mare was presented to the Michigan State University's, Large Animal Emergency service for dystocia. Clinical evaluation revealed a minimally dilated cervix on vaginal examination, with a palpable deceased fetus. Postmortem evaluation following owner-elected humane euthanasia revealed a circumferential, tan, fibrous band at the base of the uterine body that constricted the uterus and was adhered to the left and right ovaries. A routine histologic section of the incarcerating cord attached to the ovary consisted predominately of dense fibrous connective ti...
Pusterla N, Barnum S, Lawton K, Wademan C, Corbin R, Hodzic E.Contemporary data on equine herpesvirus-1 (EHV-1) genotype (non-neuropathogenic or N, neuropathogenic or D and new variant or H) in clinically diseased equids is important in order to determine the frequency of these genotypes and their association with disease expression. A total of 297 EHV-1 qPCR-positive swabs collected from 2019 to 2022 from horses with respiratory disease (EHV-1), neurological disease (equine herpesvirus-1 myeloencephalopathy [EHM]) and abortion were tested for the three different EHV-1 genotypes (N, D and H) using qPCR allelic discrimination assays. All submissions origi...
Simonin EM, Babasyan S, Tarsillo J, Wagner B.IgE+ plasmablasts develop following allergen exposure and B cell activation. They secrete IgE and therefore are directly linked to maintain the mechanisms of IgE-mediated allergies. Here, we show that the presence of IgE+ plasmablasts in peripheral blood not only coincides with clinical allergy, but also predicts the upcoming development of clinical disease. Using an equine model of naturally occurring allergy, we compared the timing of allergen exposure, arrival of IgE+ plasmablasts in peripheral blood, and onset of clinical disease. We found that IgE+ plasmablasts predict the development of ...
Peixoto Rabelo I, Barroco de Paula V, Carvalho Bustamante C, Santana AM, Gomes da Silva D, Baldassi AC, Canola PA, Araújo Valadão CA.Horses submitted to carbohydrate overload can develop laminitis due to changes in cecal pH and microbiota, followed by an increase in transmural absorption of luminal content, including bacterial toxins. In response to acute injury there is hepatic overproduction of several proteins known as acute phase proteins (APP). Few studies have evaluated protein fractionation to characterize the inflammatory response in acute laminitis. The aim of this study was to test the viability of an experimental model to induce acute laminitis, using a single carbohydrate overload, and the influence of a bufferi...
Kopper JJ.Equine rotavirus is one of the most common causes of infectious diarrhea in foals. Although the infection itself is self-limiting, the resulting diarrhea is due to multiple mechanisms and can be severe, requiring supportive care including fluid and electrolyte support. Prompt diagnosis is important for treatment and biosecurity decisions and can be achieved by several means. Prevention, while imperfect, currently relies on vaccination of pregnant mares before parturition, ingestion of adequate colostrum from vaccinated mares and biosecurity measures.
Sazmand A, Yavari M, Babaei M, Nourian A, Otranto D.Migration of Ascaris lumbricoides through the papilla of Vater in humans, and entry into the biliary tree, is well-recognised. Ascaris suum and Toxocara vitulorum have been recovered from the liver of swine and buffalo. We necropsied a Persian Kurdish filly at age 6 months, weighing ∼100 kg. Death evidently was caused by oleander (Nerium oleander) intoxication. An 8-cm adult male Parascaris was found at the lobar-left hepatic bile duct junction. We suggest that the nematode entered anteriorly into the hepatic tree, via the duodenum, major duodenal papilla, bile duct, left hepatic duct and f...
Middlebrooks B, McCue P, Nelson B, May E, Divine C, Barton C, Conley A.Disorders of sexual development (DSD) are associated with atypical chromosomal, gonadal, or phenotypic sex. It is likely that the number of cases of DSD are underestimated in the equine population. Monorchidism in the horse is very rare. This case report describes the clinical assessment of a phenotypic mare with stallion-like behavior which led to the diagnosis of a DSD. A 4-year-old Quarter Horse mare presented in good body condition, with normal external genitalia for a mare, and normal mammary glands with two bilaterally symmetric teats. No uterus, cervix, or gonads were detected on transr...
Ruby RE, Janes JG.A variety of infectious agents including viral, bacterial, and fungal organisms can cause equine abortion and placentitis. Knowledge of normal anatomy and the common pattern distribution of different infectious agents will assist the practitioner in evaluating the fetus and/or placenta, collecting appropriate samples for further testing, and in some cases, forming a presumptive diagnosis. In all cases, it is recommended to confirm the diagnosis with molecular, serologic, or microbiological testing. If a causative agent can be identified, then appropriate biosecurity and vaccination measures ca...
Azócar-Aedo L.Leptospirosis is an important zoonosis worldwide. This disease affects numerous animal species, some of them are classified as "maintenance hosts", and others are categorized as "incidental hosts". Humans are at risk of becoming infected by having contact with domestic and wild animals. In this paper, general aspects of the etiology and transmission of leptospirosis are addressed, data regarding the clinical presentation of the pathology in humans and animals are also presented, and the results of some epidemiological studies on leptospirosis carried out in Chile in different animal species an...
Shaffer SK, Stover SM, Fyhrie DP.Focal bone lesions are often found prior to clinically relevant stress-fractures. Lesions are characterized by low bone volume fraction, low mineral density, and high levels of microdamage and are hypothesized to develop when bone tissue cannot sufficiently respond to damaging loading. It is difficult to determine how exercise drives the formation of these lesions because bone responds to mechanical loading and repairs damage. In this study, we derive steady-state rate constants for a compartment model of bone turnover using morphometric data from fractured and non-fractured racehorse proximal...
Chappell DE, Barnett DC, James K, Craig B, Bain F, Gaughan E, Schneider C, Vaala W, Barnum SM, Pusterla N.A voluntary upper respiratory biosurveillance program in the USA received 9740 nasal swab submissions during the years 2008-2021 from 333 veterinarians and veterinary clinics. The nasal swabs were submitted for qPCR testing for six common upper respiratory pathogens:equine influenza virus (EIV), equine herpesvirus-1 (EHV-1), equine herpesvirus-4 (EHV-4), subspecies (), equine rhinitis A virus (ERAV), and equine rhinitis B virus (ERBV). Additional testing was performed for equine gamma herpesvirus-2 (EHV-2) and equine gamma herpesvirus-5 (EHV-5) and the results are reported. Basic frequency s...
Cullinane A, Garvey M, Walsh C, Gibbons J, Creighton A.The association between poor performance and respiratory disease in Thoroughbred racehorses that do not have a structural abnormality of the respiratory tract, is often based on anecdotal evidence. The objective of this scoping review was to examine the scientific evidence for such associations. Publications were selected based on a search of three databases (PubMed, Scopus, and CAB Direct), in English and without date restriction, followed by a screening process to exclude non-relevant papers, duplicates, and reviews. This process identified 996 publications of which 20 were analysed using th...
Labbe KA, Allshouse KA, Gilmour LJ, Arnold CE, Whitfield-Cargile CM, Griffin CE.Sinusitis is a common disease of horses yet there are a limited number of reports in the literature that describe the prevalence of infraorbital canal (IOC) pathology and headshaking behaviour in horses diagnosed specifically with primary sinusitis and secondary dental sinusitis. Given the impact that these behaviours can have on horses' intended athletic use, investigation is warranted. Objective: To determine the occurrence of IOC pathology in horses with concurrent primary or secondary dental sinusitis based on computed tomography (CT) findings and to assess whether the frequency of headsha...
Goehring LS, van Winden SC, van Maanen C, Sloet van Oldruitenborgh-Oosterbaan MM.Equine herpesvirus type 1(EHV-1)-associated myeloencephalopathy (EHM) is a rare disease affecting the central nervous system and, in particular, the spinal cord of horses. Epidemiologic data are limited, and usually are restricted to the description of a single outbreak. During an observational period of 4 years, we evaluated 9 outbreaks of EHM in The Netherlands. A risk factor analysis was done on the data from 6 outbreaks. Findings were: regular appearance of EHM outbreaks in The Netherlands (2-3/y); strong association of EHM with season; and risk factors, such as breed, sex, age, and fever....
Rikihisa Y, Perry BD.An ehrlichia was consistently isolated from the peripheral blood leukocyte fraction of ponies that had been experimentally infected with Potomac horse fever by whole blood transfusion from naturally infected horses. The organism was propagated in a human histiocyte cell line for 3 to 5 weeks and then inoculated intravenously or intradermally into healthy adult ponies. Clinical signs of Potomac horse fever, which varied in the degree of severity, occurred 9 to 14 days post-inoculation in all of the ponies. One pony died 20 days post-inoculation. The ehrlichial organism was reisolated in the hum...
Karikoski NP, McGowan CM, Singer ER, Asplin KE, Tulamo RM, Patterson-Kane JC.Laminitis in equids is a clinical syndrome usually associated with systemic disease. Endocrinopathies recently have been recognized as the most common cause of laminitis, with hyperinsulinemia playing a key role. Descriptions of laminitis-associated lesions have been confusing due to the wide range of experimental models used, failure of adequate clinical documentation for naturally occurring cases, lack of separate analysis of inflammatory and endocrinopathic laminitis, and uncertainty regarding normal morphological variation of lamellae. In this study, lamellar morphology and pathology were ...
Vatistas NJ, Snyder JR, Carlson G, Johnson B, Arthur RM, Thurmond M, Zhou H, Lloyd KL.Although gastric ulcers have been identified relatively frequently in racing Thoroughbreds, there have been no large scale studies to determine their effect on health and performance. Two hundred and two Thoroughbred horses in active race training were selected by the attending veterinarians for gastro-endoscopic examination. Images of the stomach mucosa were stored in a digitised format for subsequent evaluation. The number of ulcers and a score of severity were determined. Gastric ulceration of the squamous mucosa was identified in 82% of horses. Seventy-three (39%) horses displayed clinical...
Smith C, Skelly C, Kung N, Roberts B, Field H.Hendra virus causes sporadic but typically fatal infection in horses and humans in eastern Australia. Fruit-bats of the genus Pteropus (commonly known as flying-foxes) are the natural host of the virus, and the putative source of infection in horses; infected horses are the source of human infection. Effective treatment is lacking in both horses and humans, and notwithstanding the recent availability of a vaccine for horses, exposure risk mitigation remains an important infection control strategy. This study sought to inform risk mitigation by identifying spatial and environmental risk factors...
Scepek S, Lindau M.We have investigated the granule fusion events during exocytosis in horse eosinophils by time-resolved patch-clamp capacitance measurements. Stimulation with intracellular GTP gamma S leads to a stepwise capacitance increase by 4.0 +/- 0.9 pF. At GTP gamma S concentrations < 20 microM the step size distribution is in agreement with the granule size distribution in resting cells. Above 80 microM the number of steps is reduced and very large steps occur. The total capacitance increase, however, is unaffected. These results show that at high GTP gamma S concentrations granule--granule fusion o...
Szóstek-Mioduchowska AZ, Lukasik K, Skarzynski DJ, Okuda K.Transforming growth factor (TGF)-β1 not only regulates cell growth, development, and tissue remodeling, but it also participates in the pathogenesis of tissue fibrosis. In the equine endometrium, the concentration of TGF-β1 is correlated with endometrosis (equine endometrial fibrosis). In other tissues, TGF-β1 induces differentiation of many cell types into myofibroblasts. These cells are characterized by α-smooth muscle actin (α-SMA) expression and an ability to deposit excessive amounts of extracellular matrix (ECM) components. The aim of the study was to determine whether TGF-β1 plays...
Bailey SR, Habershon-Butcher JL, Ransom KJ, Elliott J, Menzies-Gow NJ.To determine the metabolic phenotype of a group of laminitis-prone ponies when at pasture in summer, compared with when at pasture in winter. Methods: 40 ponies of various breeds predisposed to recurrent pasture-associated laminitis and 40 unaffected control ponies. Methods: Body condition score and size of the crest of the neck were assessed, blood samples obtained, and blood pressure measured by use of an indirect oscillometric technique, while ponies were kept on winter pasture (last week of November or beginning of December) and again on summer pasture (June). Serum insulin concentration a...
Imam M, Alrashid B, Patel F, Dowah ASA, Brown N, Millard A, Clokie MRJ, Galyov EE.Phages are the most abundant biological entity on Earth. There are many variants in phage virion sizes, morphology, and genome sizes. Large virion sized phages, with genome sizes greater than 200 kbp have been identified and termed as Jumbo phages. These phages exhibit certain characteristics that have not been reported in phages with smaller genomes. In this work, a jumbo phage named MIJ3 (vB_PaeM_MIJ3) that infects PAO1 was isolated from an equine livery yard in Leicestershire, United Kingdom. The genome and biological characteristics of this phage have been investigated. MIJ3 is a Myovirus...
Bortolami A, Zendri F, Maciuca EI, Wattret A, Ellis C, Schmidt V, Pinchbeck G, Timofte D. are opportunistic pathogens with the potential to cause a variety of infections in both humans and animals and in many cases have developed antimicrobial resistance. In this study, we characterized extended-spectrum cephalosporin resistant (ESCR) isolates from diseased companion animals (dogs, cats, and horses) and related the results to clinical findings. ESCR clinical isolates obtained over a 6-year period were screened for extended-spectrum β-lactamase (ESBL) and/or plasmid mediated AmpC (pAmpC) and virulence markers likely to be associated with extraintestinal pathogenic (ExPEC). ESBL...
Traub-Dargatz JL, Kopral CA, Seitzinger AH, Garber LP, Forde K, White NA.To estimate the national incidence of, operation-level risk factors for, and annual economic impact of colic among horses in the United States during 1998 and 1999. Methods: Epidemiologic survey. Methods: 21,820 horses on 1,026 horse operations in 28 states. Methods: Horses were monitored for colic for 1 year, and results were recorded in a log that was collected quarterly. Operation-level data were collected via 4 on-site personal interviews. Associations between colic and independent variables adjusted for size of operation were determined. Results: Annual national incidence of colic in the ...
Traub-Dargatz JL, Pelzel-McCluskey AM, Creekmore LH, Geiser-Novotny S, Kasari TR, Wiedenheft AM, Bush EJ, Bjork KE.A large multistate outbreak of equine herpesvirus myeloencephalopathy (EHM) occurred in May 2011 among horses that participated in a competitive event. Objective: To identify EHM risk factors among horses with a common exposure venue. Methods: A total of 123 horses: 19 horses with EHM, 14 equine herpesvirus-1 cases with no reported neurologic signs, and 90 control horses. Methods: EHM case survey data were compared with data from EHV-1 cases with no neurologic signs and healthy controls using univariable and multivariable methods. Results: Significant factors associated with higher risk for EH...
Valentine BA.A study of 57 cutaneous melanocytic tumors from 53 horses revealed 4 distinct clinical syndromes: melanocytic nevus, dermal melanoma, dermal melanomatosis, and anaplastic malignant melanoma. Melanocytic nevus and anaplastic melanoma each had histopathologic features that distinguished them from dermal melanoma and dermal melanomatosis. Dermal melanoma and dermal melanomatosis were histologically similar but could be differentiated by their clinical features. Melanocytic nevi were diagnosed in 29 horses with an average age of 5 years; they were solitary, superficial masses that occurred in both...
Luchs A, da Costa AC, Cilli A, Komninakis SCV, Carmona RCC, Boen L, Morillo SG, Sabino EC, Timenetsky MDCST.In 2013, the equine-like G3P[8] DS-1-like rotavirus (RVA) strain emerged worldwide. In 2016, this strain was reported in northern Brazil. The aims of the study were to conduct a retrospective genetic investigation to identify the possible entry of these atypical strains in Brazil and to describe their distribution across a representative area of the country. From 2013 to 2017, a total of 4226 faecal samples were screened for RVA by ELISA, PAGE, RT-PCR and sequencing. G3P[8] represented 20.9 % (167/800) of all RVA-positive samples, further subdivided as equine-like G3P[8], DS-1-like (11.0 %...
Milinovich GJ, Burrell PC, Pollitt CC, Klieve AV, Blackall LL, Ouwerkerk D, Woodland E, Trott DJ.Alimentary carbohydrate overload is a significant cause of laminitis in horses and is correlated with drastic shifts in the composition of hindgut microbiota. Equine hindgut streptococcal species (EHSS), predominantly Streptococcus lutetiensis, have been shown to be the most common microorganisms culturable from the equine caecum prior to the onset of laminitis. However, the inherent biases of culture-based methods are estimated to preclude up to 70% of the normal caecal microbiota. The objective of this study was to evaluate bacterial population shifts occurring in the equine caecum throughou...
Mellor PS, Boorman J.African horse sickness virus (AHSV) and bluetongue virus (BTV) are dsRNA viruses within the genus Orbivirus. Both are able to cause non-contagious, infectious arthropod-borne diseases in their respective vertebrate hosts. AHSV infects equines and occasionally dogs, whereas BTV replicates in ruminants. The disease caused by AHSV is usually at its most severe in horses, whereas certain breeds of sheep are particularly sensitive to BTV infection. AHSV is endemic in sub-Saharan Africa but periodically makes brief excursions beyond this area. BTV occurs much more widely and can be found in a band a...
Tenzin , Sharma B, Dhand NK, Timsina N, Ward MP.From January through July 2008, rabies reemerged in the Chhukha district of southwestern Bhutan. To clarify the distribution and direction of spread of this outbreak, we mapped reported cases and conducted directional tests (mean center and standard deviational ellipse). The outbreak resulted in the death of 97 animals (42 cattle, 52 dogs, and 3 horses). Antirabies vaccine was given free of charge to ≈674 persons suspected to have been exposed. The outbreak spread south to north and appeared to follow road networks, towns, and areas of high human density associated with a large, free-roaming...
Morgan R, Keen J, McGowan C.Laminitis is one of the most common and frustrating clinical presentations in equine practice. While the principles of treatment for laminitis have not changed for several decades, there have been some important paradigm shifts in our understanding of laminitis. Most importantly, it is essential to consider laminitis as a clinical sign of disease and not as a disease in its own right. Once this shift in thinking has occurred, it is logical to then question what disease caused the laminitis. More than 90 per cent of horses presented with laminitis as their primary clinical sign will have develo...
Lyons S, Kapoor A, Schneider BS, Wolfe ND, Culshaw G, Corcoran B, Durham AE, Burden F, McGorum BC, Simmonds P.Non-primate hepacivirus (NPHV), equine pegivirus (EPgV) and Theiler's disease associated virus (TDAV) are newly discovered members of two genera in the Flaviviridae family, Hepacivirus and Pegivirus respectively, that include human hepatitis C virus (HCV) and human pegivirus (HPgV). To investigate their epidemiology, persistence and clinical features of infection, large cohorts of horses and other mammalian species were screened for NPHV, EPgV and TDAV viraemia and for past exposure through serological assays for NPHV and EPgV-specific antibodies. NPHV antibodies were detected in 43% of 328 ho...
Valberg SJ, Sponseller BT, Hegeman AD, Earing J, Bender JB, Martinson KL, Patterson SE, Sweetman L.We hypothesised that seasonal pasture myopathy (SPM), which closely resembles atypical myopathy (AM), was caused by ingestion of a seed-bearing plant abundant in autumn pastures. Objective: To identify a common seed-bearing plant among autumn pastures of horses with SPM, and to determine whether the toxic amino acid hypoglycin A was present in the seeds and whether hypoglycin metabolites were present in SPM horse serum or urine. Methods: Twelve SPM cases, 11 SPM pastures and 23 control farms were visited to identify a plant common to all SPM farms in autumn. A common seed was analysed for amin...
Smith KC, Blunden AS, Whitwell KE, Dunn KA, Wales AD.A detailed review of laboratory records for equine abortion is fundamental in establishing current disease trends and suggesting problems important for further research. Objective: To review the causes of abortion and neonatal death in equine diagnostic submissions to the Animal Health Trust over a 10 year period. Methods: The diagnoses in 1252 equine fetuses and neonatal foals were reviewed and analysed into categories. Results: Problems associated with the umbilical cord, comprising umbilical cord torsion and the long cord/cervical pole ischaemia disorder, were the most common diagnoses (38....
Harrold SM, Cook SJ, Cook RF, Rushlow KE, Issel CJ, Montelaro RC.Equine infectious anemia virus (EIAV) infection of horses is characterized by recurring cycles of disease and viremia that typically progress to an inapparent infection in which clinical symptoms are absent as host immune responses maintain control of virus replication indefinitely. The dynamics of EIAV viremia and its association with disease cycles have been well characterized, but there has been to date no comprehensive quantitative analyses of the specific tissue sites of EIAV infection and replication in experimentally infected equids during acute disease episodes and during asymptomatic ...
Amtmann E, Müller H, Sauer G.Bovine papilloma virus (BPV) appears to be the etiological agent of common equine connective tissue tumors. We investigated the physical state of the viral DNA within such tumors and found no indication for integration into the host genome. The BPV genomes were present as free circular episomes. Two equine sarcoids were shown to contain multiple copies of free circular BPV type 1 (BPV-1) DNA. When the tumors were digested with several single-cut restriction enzymes, there were only form III BPV-1 DNA sequences could be revealed. One of the sarcoids contained, apart from wild-type BPV-1 DNA, a ...
Pirie RS, Collie DD, Dixon PM, McGorum BC.Equine heaves is a naturally occurring organic dust-induced asthma characterized by airway neutrophilia, mucus hypersecretion and obstructive lung dysfunction. However, the relative role of different dust components in disease severity remains unclear. Objective: This study investigated the relative contribution of inhaled endotoxin and organic dust particulates (mainly mould spores) in inducing heaves in heaves-susceptible horses. Methods: Control and heaves-susceptible horses received inhalation challenges with hay dust suspension (HDS) before and after lipopolysaccharide (LPS) depletion. He...
Scepek S, Coorssen JR, Lindau M.Using the patch-clamp technique, we studied the role of protein phosphorylation and dephosphorylation on the exocytotic fusion of secretory granules with the plasma membrane in horse eosinophils. Phorbol 12-myristate 13-acetate (PMA) had no effect on the amplitude and dynamics of degranulation, indicating that the formation of fusion pores is insensitive to activation of protein kinase C (PKC). Fusion pore expansion, however, was accelerated approximately 2-fold by PMA, and this effect was abolished by staurosporine. Elevating intracellular Ca2+ to 1.5 microM also resulted in a 2-fold accelera...
Blackmore CG, Stark LM, Jeter WC, Oliveri RL, Brooks RG, Conti LA, Wiersma ST.After West Nile virus (WNV) was first detected in Florida in July 2001, intensive surveillance efforts over the following five months uncovered virus activity in 65 of the state's 67 counties with 1,106 wild birds, 492 horses, 194 sentinel chickens, and 12 people found infected with the virus. Thirteen of 28 mosquito isolations came from Culex mosquitoes. As seen in the northeastern United States, wild bird mortality was the most sensitive surveillance method. However, unlike the predominantly urban 1999 and 2000 epizootics, the Florida transmission foci were rural with most activity detected ...
