Disease outbreaks in horses refer to the occurrence and spread of infectious diseases within equine populations. These outbreaks can be caused by various pathogens, including bacteria, viruses, and parasites, and can lead to significant health issues in affected horses. Common diseases that may result in outbreaks include equine influenza, equine herpesvirus, strangles, and equine infectious anemia. The transmission of these diseases can occur through direct contact, environmental exposure, or vectors such as insects. Disease outbreaks can have substantial impacts on horse health, welfare, and the equine industry as a whole. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, transmission dynamics, and management strategies associated with disease outbreaks in equine populations.
HAMMON WM, REEVES WC.In three cases of encephalitis in humans that occurred in the area where the newly described California virus was isolated from mosquitoes, serological evidence seemed to indict the California virus as the etiological agent. In the case of an infant with very severe disease, the serological evidence was convincing; the evidence was almost as strong in the case of a seven-year-old boy; the results in an adult were equivocal. Inapparent infection in man is quite common as indicated by neutralization tests on the sera of nearly 600 residents of California, but encephalitic manifestations of infec...
Hain-Saunders N, Knight DR, Bruce M, Riley TV.Recent increases in community-associated Clostridioides difficile infections have highlighted the importance of monitoring toxigenic C. difficile from animal and environmental sources. We provide the complete circularized genomes of two toxigenic C. difficile strains isolated from feral horse faeces. Genome N64 (sequence type 964) consists of a single chromosome of 4,078,791 bp, while genome H251 (sequence type 963) comprises one chromosome (4,304,722 bp) and three plasmids (150,942 bp, 11,534 bp, and 9,074 bp).
MacNeill AL, Micheloud JF, Parvin R, Gjessing M, Airas NA, Sant'Ana FJF, Adamek M.Zoonotic poxviruses, including monkeypox virus (MPV), the causative agent for Mpox disease, have gained significant media and scientific attention due to recent outbreaks in human populations across the globe. The increase in human cases of poxvirus infection is not unexpected, as routine vaccination against smallpox (a disease caused by the poxvirus variola virus, which cross protects against other orthopoxviruses) was discontinued in the 1980s after its eradication. Large numbers of vertebrate and invertebrate species are susceptible to infection by . Clinical signs and histologic lesions ca...
Rakaki ME, van der Walt M, Williams J, Venter M.We detected Shuni virus in horses and ovine fetuses and Shamonda virus in a caprine fetus in South Africa. We identified a Shuni/Shamonda virus reassortant in a horse and Shuni/Caimito, Shamonda/Caimito, and Shamonda/Sango virus reassortants in Culicoides midges. Continued genomic surveillance will be needed to detect orthobunyavirus infections in Africa.
West Nile virus (WNV) is a mosquito-borne flavivirus that remains an important public and veterinary health concern across Europe. Periodic outbreaks affecting humans, horses, and wildlife highlight the complex ecological interactions underlying viral circulation. This narrative review aims to synthesize current knowledge regarding WNV epidemiology, transmission dynamics, and surveillance strategies in Europe, with particular attention to the Romanian context. Available surveillance data indicate recurrent seasonal transmission in several European regions; however, reported case numbers may be...
AbouEl Ela NH, El Araby IE, Saleh AA, Abd El-Fattah AH, Hagag NM, Brooks SA, Radwan MA, Kalbfleisch T.Lavender foal syndrome (LFS) is a fatal hereditary condition that is inherited in an autosomal recessive pattern. This detrimental mutation is more common in Arabian foals of Egyptian origin than foals from other bloodlines. Heterozygous horses are carriers of the LFS trait and appear normal, while recessive homozygous foals died shortly after birth due to serious complications. In Egypt, in 2014, an Egyptian foal died after manifestations of neurological signs and abnormal coat colour as LFS signs. Therefore, it is important to identify LFS carriers in the population of Arabian horses in Egyp...
Pozio E, Celano GV, Sacchi L, Pavia C, Rossi P, Tamburrini A, Corona S, La Rosa G.Epidemiological investigations conducted during 10 trichinellosis outbreaks between 1975 and 1994 showed that horse-meat was the probable source of infection. Though hundreds of thousands of horses have been examined at abattoirs in America and Europe to detect Trichinella infection by artificial digestion or trichinelloscopy, an infected horse has never been detected during routine analysis, which consists of examining 1 g of tissue muscle from the diaphragm. In November 1996, a naturally infected horse imported from Romania was detected in Southern Italy. The parasite was identified as Trich...
Lord CC, Woolhouse ME, Mellor PS.Factors affecting epidemics of African horse sickness in Spain were studied using a mathematical model. The model examined the likelihood of an epidemic after the introduction of the virus, and the effectiveness of vaccination strategies. Two host species (horses and donkeys) and one vector species (the biting midge Culicoides imicola) were included. A stratified random sampling method (Latin hypercube sampling) was used for sensitivity analysis of the likelihood of an epidemic. Systematic variation of vaccination parameters was used to consider alternative control strategies. In general, when...
Tobin T, Watt DS, Kwiatkowski S, Tai HH, Blake JW, McDonald J, Prange CA, Wie S.We have introduced large scale non-isotopic immunoassay testing into pre- and post-race drug testing in racehorses. The technologies utilized are Particle Concentration Fluorescence Immuno Assay (PCFIA) and the one-step Enzyme Linked Immuno Sorbent Assay (ELISA). These technologies are rapid, inexpensive, and highly effective. On introduction into post-race testing in the Western United States, these ELISA tests exposed several previously undetected patterns of drug abuse. The drugs detected were buprenorphine, oxymorphone, mazindol, sufentanil and cocaine. This led to the suspension of a larg...
Page AE, Stills HF, Chander Y, Gebhart CJ, Horohov DW.Lawsonia intracellularis is the causative agent of equine proliferative enteropathy (EPE), a disease for which no large-scale seroprevalence studies have been conducted. Objective: To validate and use an equine-specific enzyme-linked immunosorbent assay (ELISA) for L. intracellularis to determine the seroprevalence of L. intracellularis on numerous farms. Methods: An ELISA, in which purified antigen was used, was adapted from previous work in swine. A total of 337 Thoroughbreds from 25 central Kentucky farms were enrolled and monthly serum samples collected from August 2010 to January/February...
Durham AE.Outbreaks of liver disease in horses are common but the etiology of most remains unknown. Forage mycotoxins have been suspected to be a cause. Objective: To examine the association between outbreaks of liver disease and the presence of mycotoxins in forage stored on the same premises. Methods: Premises were identified where ≥4 horses were contemporaneously affected by liver disease, and a control group was formed from premises where ≥4 horses had been examined and found to have no evidence of liver disease. Methods: Forage was collected from 29 case and 12 control premises. The forage was ...
Page AE, Partridge E, Erol E, Scoggin KE, Fedorka CE, Ruby RE, Ball BA, Horohov DW, Adam E.Cases of nocardioform placentitis are characterized by focal, mucoid placentitis resulting in late-term abortion, premature birth, or small, full-term foals, occur sporadically, and are most commonly associated with Crossiella equi and Amycolatopsis spp. infection. The goal of this project was to develop an enzyme-linked immunosorbent assay (ELISA) for quantifying antibodies against Crossiella equi and Amycolatopsis spp. and utilize the ELISA to determine when exposure occurs. Serum samples collected during the 2020 foaling season from Crossiella equi (n = 8) and Amycolatopsis spp. (n = 32...
Kaaden OR, Truyen U.There is a continuous change in viral epidemics with respect to clinical symptoms, their duration or disappearance and the emergence of new diseases. This can be observed both in human and animal diseases. This evolution of virus diseases is mainly related to three factors: etiological agent, host and environment. As far as genetic alterations of the virus are concerned, two major mechanisms are involved: 1) mutations such as recombination and reassortment; 2) selection for resistance or susceptibility. The epidemiology of newly emerged virus diseases in man and animals, such as AIDS and hemor...
Kimpfler S, Pospischil A, Rüsch P, Sydler T.One of the essential tasks of veterinary pathology is the gross and microscopic examination of animals post mortem. Frequently requests are made for the cause of disease or death in the absence of a precise history or an otherwise specific assignment e.g. whether a notifiable disease is involved. The general examination is supplemented by a spectrum of additional examinations depending on the case whereas attempts are made to keep the costs within limits and to answer the client's request with justifiable effort. 36,365 necropsy cases and 9192 organs submitted between 1988 and 2004 were analys...
Christensen LS.Borna disease virus has long been recognized as a cause of sporadic cases and epidemics of meningoencephalomyelitis in horses and sheep in southern parts of Germany. however, sero-epidemiological surveillances indicate that Borna disease virus has a global distribution in horses, without the recognition of clinical manifestations associated with the infection, in other parts of the world. During the past five years evidence has been presented suggesting that humans also can become infected with this virus or a closely related virus. A significantly increased sero-prevalence is seen in patient ...
Wiedenheft AM, Traub-Dargatz JL, Gillette SC, O'Keefe GJ, Rao S, Salman MD.The purpose of this study was to assess the effectiveness of two different methods of online education using the knowledge base of African horse sickness (AHS) among US equine veterinarians as a model. An e-mail was sent to US veterinary members of the American Association of Equine Practitioners (AAEP), inviting them to participate in a complementary online educational opportunity. We determined participants' baseline knowledge of AHS by their responses in an AHS case scenario. Participants were then randomly assigned to either a Webinar module or a text-formatted module, followed by an educa...
Davies MR.Despite tight biosecurity measures, an outbreak of respiratory disease rapidly spread across the Icelandic equine population in 2010. Horse transportation was brought to a halt in order to contain the spread of the infectious agent. In a recent article, Björnsdóttir and colleagues (S. Björnsdóttir et al., mBio 8:e00826-17, 2017, https://doi.org/10.1128/mBio.00826-17) employ the power and resolution of "genomic epidemiology," the combination of whole genomic sequencing and epidemiological approaches, to examine the source and spread of the outbreak. Intriguingly, the outbreak was not viral ...
Thein P, Essich G.An investigation was carried out upon occurrence and course of infectious and non infectious diseases as well as the mortality in foals born and raised at the State Stud Marbach/Lauter between 1982 and 1991. The foals have been investigated from birth to weaning, they consisted of 177 Thoroughbred Arabians and 285 German Warmblood foals (total 462 foals). The diseases were divided into pre-, peri- and postnatal according to their known or assumed cause and onset. There was a preponderance of prenatal diseases (11.25%) whereas the perinatal rate was 1.30% and the postnatal rate of diseases was ...
Monzon CM, Jara GA, Hoyos CB.The usefulness of the direct agglutination test (DA) to diagnose Mal de Caderas disease was evaluated. Forty four sera samples from two lots of horses with natural T. evansi infection (Lot 1 and Lot 2) were used. Thirteen (81.2%) of sixteen horses in which parasites were isolated gave positive agglutination titres (> or = 1:512) in the DA test. Treatment of these positive sera with 2-mercaptoethanol drops three to eight dilutions the agglutination titres in twelve samples (92%), showing the IgM nature of these antibodies. The DA test was also positive in seventeen of twenty eight horses in ...
Sergeant ES, Cowled BD, Bingham P.This observational study was undertaken in order to evaluate the diagnostic specificity of the blocking enzyme-linked immunosorbent assay (bELISA) for serum antibodies to influenza A virus nucleoprotein during the equine influenza (EI) outbreak response in New South Wales, Australia, in 2007. Using data collected during the outbreak response, bELISA testing data were collated for assumed uninfected horses from areas where EI infection was never recorded. Diagnostic specificity of the bELISA used during the EI response was high, but varied significantly between some regions, although the reason...
Miszczak F, Pronost S, Vabret A.Equine arteritis virus (EAV) is the causative agent of equine viral arteritis, a disease observed only in equids. EAV is the prototype of the family Arteriviridæ within the order Nidovirales. EAV is an enveloped, positive-sense, single-stranded RNA virus with a considerable variation in the genome as observed in other RNA viruses. During natural infections, EAV may cause abortion and persistent subclinical infections in stallions which can shed the virus in the semen for years, or even lifetime. Chronically infected stallions represent the natural reservoir of the virus. They ensure the persi...
Sloet van Oldruitenborgh-Oosterbaan MM, Schipper FC, Goehring LS, Gremmels JF.In the course of several days most of the 40 riding-school horses turned out in paddocks developed ataxia of variable severity. Five of these horses showed severe ataxia and tremors, became paralyzed and were euthanized. Eleven privately-owned horses which were stabled on the same premises showed no clinical signs. The most likely diagnosis seemed to be the 'neurological form of EHV1', although the signs were not entirely typical. A few weeks later a second outbreak occurred among the riding-school horses and one of the privately-owned horses also showed signs of ataxia. In the meantime it had...
Torres BT, Dover RK, Sapora JA, Sandberg GS, Budsberg SC.To document the publication rate of abstracts presented at 10 ACVS conferences and report the time required for publication and level of evidence. Methods: Literature review. Methods: All scientific abstracts published in the ACVS proceedings from 2001 to 2010 were reviewed. The level of evidence of each abstract was evaluated and scored (1-4). Publication information was determined after a broad bibliographic search through multiple online databases. Results: The overall publication rate for ACVS abstracts (n=1,395) was 66% and 11% were published before conference presentation. The majority o...
Vercauteren G, van der Heyden S, Lefère L, Chiers K, Laevens H, Ducatelle R.This report concerns 2 horses that suffered typical clinical signs of atypical myopathy (AM) and equine grass sickness (EGS) concurrently. Clinical details and pathological lesions of the cases are described. EGS and AM are relatively rare diseases and the concurrency of the diseases in the same animals is therefore considered unlikely to be a coincidence. However, it is not suggested that the evidence shows a common aetiology but rather the existence of common predisposing causes.
Gehlen H, Rutenberg D, Simon C, Reinhold-Fritzen B, Drozdzewska K.The aim of this review is to describe general guidelines of hygiene measures in the horse stable as well as to provide current recommendations for an outbreak of a common infectious disease. General cleanliness, hand hygiene, avoidance of stress, regular deworming, and vaccinations belong to the basic hygiene measures in a horse herd. All new or returning equids should be submitted to a quarantine period as an important prevention measure. Repeated washing and disinfection of hands may prevent spreading of infectious agents to people and horses.The conception of a hygiene plan, including gener...
More S, Bøtner A, Butterworth A, Calistri P, Depner K, Edwards S, Garin-Bastuji B, Good M, Gortázar Schmidt C, Michel V, Miranda MA, Nielsen SS....Equine encephalomyelitis (Eastern and Western) has been assessed according to the criteria of the Animal Health Law (AHL), in particular criteria of Article 7 on disease profile and impacts, Article 5 on the eligibility of equine encephalomyelitis (Eastern and Western) to be listed, Article 9 for the categorisation of equine encephalomyelitis (Eastern and Western) according to disease prevention and control rules as in Annex IV, and Article 8 on the list of animal species related to equine encephalomyelitis (Eastern and Western). The assessment has been performed following a methodology compos...
Cardenas NC, Sanchez F, Lopes FPN, Machado G.Most animal disease surveillance systems concentrate efforts in blocking transmission pathways and tracing back infected contacts while not considering the risk of transporting animals into areas with elevated disease risk. Here, we use a suite of spatial statistics and social network analysis to characterize animal movement among areas with an estimated distinct risk of disease circulation to ultimately enhance surveillance activities. Our model utilized equine infectious anemia virus (EIAV) outbreaks, between-farm horse movements, and spatial landscape data from 2015 through 2017. We related...
Mumford EL, McCluskey BJ, Traub-Dargatz JL, Schmitt BJ, Salman MD.To determine potential risk factors for vesicular stomatitis (VS) in Colorado livestock in 1995 and evaluate VS virus (VSV) exposure of Colorado livestock in 1996. Methods: Retrospective case-control study of VS risk factors and seroprevalence evaluation. Methods: Premises included 52 that had VS-positive animals and 33 that did not have VS-positive animals during the 1995 epidemic, and 8 in the vicinity of premises that had VS-positive animals during the 1995 epidemic. Methods: Layout and management data for premises were collected during site visits in 1996. Signalment and management data we...
Lotstra RJ, van den Broek J, Power T, Marr CM, Wijnberg ID.Atrial fibrillation is a common equine arrhythmia. Quinidine alone, or with digoxin are common treatments. Studies on outcome in Warmblood populations in which duration of the AF is often unknown are limited. Objective: To identify the factors that are associated with the success of full treatment cardioversion with oral medication, and establish whether there are differences in these factors between institutions. Methods: Retrospective case series using patient records of Equine University Clinic of Utrecht University and Rossdales Equine Hospital, Newmarket. Methods: Forty-nine horses treate...
Morehead JP, Blanchard TL, Thompson JA, Brinsko SP.To determine features of an early fetal loss (EFL) syndrome and evaluate potential risk factors for EFL in Thoroughbred broodmares on 4 farms in central Kentucky. Methods: Retrospective study. Methods: 288 pregnant broodmares. Methods: Year-2001 breeding records for 288 Thoroughbred broodmares were examined. Early fetal loss was defined as loss of a fetus that was viable at > or = 40 days of gestation but was subsequently lost by 5 months of gestation. Results: Overall 2001 EFL rate was 25% (73/288), median gestational age at time of fetal loss was 77 days, and median date of loss was May 7...
