Disease transmission in horses refers to the spread of infectious agents such as bacteria, viruses, fungi, and parasites among equine populations. These pathogens can be transmitted through various routes, including direct contact, vector-borne transmission, or environmental exposure. Factors influencing disease transmission include horse density, management practices, and biosecurity measures. Understanding the mechanisms and conditions that facilitate the spread of diseases is essential for developing effective prevention and control strategies. This page compiles peer-reviewed research studies and scholarly articles that investigate the modes of transmission, risk factors, and management practices related to infectious diseases in horses.
Scott GR.Twelve DNA viruses and forty‐three RNA viruses are known to infect horses. In addition, there are three unclassified viruses and, at least, three alleged viruses infecting horses. Differential diagnosis is difficult. At least twenty‐eight of the fifty‐eight viruses induce clinical disease but the range of syndromes is limited; eleven provoke respiratory symptoms and eleven cause encephalitis. Thirty‐four equine viruses with a limited geographical distribution are transmitted by arthropod vectors. Twenty viruses are spread by contact and their distribution, in general, is global. The ve...
Brown J, Physick-Sheard P, Greer A, Poljak Z.Horse movements are one of the most important factors for the spread of equine diseases, and past epidemics indicate that contact networks play an important role. Network analysis was used to describe the spatial and temporal characteristics of horse movements between Standardbred racetracks in Canada and the United States during 2019, and to characterize the network to provide a better understanding of the potential racetrack-to-racetrack spread of infectious disease within the network. Networks were constructed and analyzed as an overall network (the entire study period) and monthly networks...
O'Connor M.Zoonotic diseases are those which originate in animals but are transmitted to humans often through an intermediate host such as a wild animal. In Australia Hendra virus (HeV) is a disease of horses with occasional human fatalities and which is spread by the fruit bat. This article explores the lessons learnt from managing the Queensland outbreak of HeV in 1994. The legal framework for the notification and management of prohibited matter including zoonotic diseases in Queensland and New South Wales has been strengthened by provisions in the Biosecurity Act 2015 (NSW) which create strong penalti...
Cohen ND, Carey VJ, Donahue JG, Seahorn JL, Brown SE, Riddle TW.To characterize the temporality of dates of breeding and abortion classified as mare reproductive loss syndrome (MRLS) among mares with abortions during early gestation. Methods: 2,314 mares confirmed pregnant at approximately 28 days after breeding from 36 farms in central Kentucky, including 515 mares that had early-term abortions. Methods: Farm veterinarians and managers were interviewed to obtain data for each mare that was known to be pregnant to determine pregnancy status, breeding date, last date known to be pregnant, and date of abortion. Results: Mares bred prior to April 1, 2001, app...
Nielsen MK, Leathwick DM, Sauermann CW.Over the past three decades, equine strongylid egg reappearance periods (ERPs) have shortened substantially for macrocyclic lactone anthelmintics. The ERPs of ivermectin and moxidectin were originally reported in the 8-10 and 12-16 week ranges, respectively, but several recent studies have found them to be around 4-5 weeks for both actives. This loss of several weeks of suppressed strongylid egg output could have substantial implications for parasite control. This study made use of a computer simulation model to evaluate the impact of shortened ERPs on the anthelmintic performance of ivermecti...
Dryburgh EL, Marsh AE, Dubey JP, Howe DK, Reed SM, Bolten KE, Pei W, Saville WJ.Sarcocystis neurona is considered the major etiologic agent of equine protozoal myeloencephalitis (EPM), a neurological disease in horses. Raccoon ( Procyon lotor ) is considered the most important intermediate host in the life cycle of S. neurona in the United States; S. neurona sarcocysts do mature in raccoon muscles, and raccoons also develop clinical signs simulating EPM. The focus of this study was to determine if sarcocysts would develop in raccoons experimentally inoculated with different host-derived strains of in vitro-cultivated S. neurona merozoites. Four raccoons were inoculated wi...
Nowotny N, Bürki F.Three cases of abortions were diagnosed as caused by Equine Arteritis Virus (EAV) by isolation and typing of this virus from the respective fetuses. All 3 abortions were single cases, one occurring on a stud with Iceland Ponies, one with Warmbloods, one with Lipizzaner horses. On each stud horses of the respective breed were kept exclusively, therefore there existed no epidemiologic link. By means of seroneutralization tests performed on in contact horses it could be shown, that EAV had only been introduced recently into the stud with the Iceland Ponies. An extraneous mare stabled temporarily ...
Herholz C, Kopp C, Wenger M, Mathis A, Wägeli S, Roth N.Female tabanid flies (Diptera: Tabanidae) can be a serious nuisance for horses because of their painful bites during blood feeding. They also play a primary role in mechanical transmission of a lentivirus causing Equine Infectious Anemia (EIA), a virus that has spread within Europe in recent years. According to the European law for products intended for use as a repellent on horses (recreational and sport horses), a field test is mandatory to demonstrate sufficient repellency of such a substance against the specific target fly species, but currently no agreed protocols are available for testin...
Pusterla N, Hagerty D, Mapes S, Vangeem J, Groves LT, Dinucci M, Fielding LC, Higgins JC.This study investigated the role of a district irrigation canal in Nevada County, California, USA, as the point source of infection for Neorickettsia risticii, causative agent of equine neorickettsiosis (EN). A total of 568 freshwater snails comprising Juga spp., Planorbella subcrenata (Carpenter, 1857) (Rough Rams-horn), Physella virgata (Gould, 1855) (Protean Physa) and feces from three horses with EN were collected and tested for N. risticii by real-time PCR. A total of four freshwater snails tested PCR positive for N. risticii. Phylogenetic analysis showed 99.8-100% homology between the di...
Edwards GT.Of 1388 horses and ponies examined at two abattoirs in the north of England from November 1979 to September 1981, 123 (8.7 per cent) showed evidence of hydatid infection. Prevalence of infection was closely related to age, rising from nil in animals up to two years old to over 20 per cent of those over eight years. Full-mouthed horses and ponies had similar prevalence rates (14.9 and 14.5 per cent, respectively), but horses had nearly twice as many viable infections as ponies. The prevalence of infection varied with the region of origin of full-mouthed horses and ponies, with 18 per cent of th...
Khan A, Mushtaq MH, Muhammad J, Ahmed B, Khan EA, Khan A, Zakki SA, Altaf E, Haq I, Saleem A, Warraich MA, Ahmed N, Rabaan AA.There are different opinions around the World regarding the zoonotic capability of H3N8 equine influenza viruses. In this report, we have tried to summarize the findings of different research and review articles from Chinese, English, and Mongolian Scientific Literature reporting the evidence for equine influenza virus infections in human beings. Different search engines i.e. CNKI, PubMed, ProQuest, Chongqing Database, Mongol Med, and Web of Knowledge yielded 926 articles, of which 32 articles met the inclusion criteria for this review. Analyzing the epidemiological and Phylogenetic data from ...
Quieroz AO, Nehme-Russell NS, Brandão A, Jansen AM.'Mal de Cadeiras' is a disease which causes great mortality in horses in the Pantanal Matogrossense region, Brazil. The agent of this disease is Trypanosoma evansi, a kinetoplastid flagellate which belongs to the Trypanosomatidae family, classified into the Salivarian section. Transmission occurs mechanically by haematophagous Diptera, mainly by Stomoxys sp. and Tabanus sp. and vampire bats. Outbreaks of Mal de Cadeiras in horses result in economic losses, thus limiting their use in cattle raising. Ten isolates of T. evansi recently derived from coati (Nasua nasua, Carnivora, Procyonidae), hor...
Cleve H, Schmid DO.An apparent incompatibility in the GC/DBP system in a mare and her colt was found after classification by polyacrylamide gel electrophoresis. Because of this observation an analysis of the equine GC/DBP system by isoelectric focusing and subsequent immunoprinting was initiated. Further GC subtypes, however, were not encountered: the three phenotypes GC F, FS and S were also delineated by this method. The GC types in the case of disputed descent were dissolved: GC S was found in the mare and GC FS in her colt as well as in another of her male offspring. It is proposed that a rare GC mutant is r...
Mulhern FJ.There is an increasing need for the veterinary profession to meet the new challenges brought about by increased and intensified livestock production. These challenges consist of control and eradication of diseases, the humane treatment of animals and the prevention of transmission of disease from animals or animal products to man. Examples are given of the contribution which regulatory medicine activities have made to the prevention/control/eradication of screw worm, foot-and-mouth disease, Venezuelan equine encephalomyelitis, Newcastle disease, bovine brucellosis, hog cholera, and certain oth...
Crosby B, Crespo ME.Venezuelan Equine Encephalitis Virus (VEEV) is the causative viral pathogen of Venezuelan Equine Encephalitis (VEE). Outbreaks frequently involve both equines – including horses, donkeys, mules, zebras – and humans. Outbreaks may range over a large geographic area and may last for several months to years. Sporadic epidemic outbreaks occur most commonly in Central and South America. VEEV exists as both a natural pathogen and a laboratory-developed biologic weapon. Outbreaks have been reported in several South and Central American countries, including Venezuela, Colombia, Peru, Ecuador, C...
Lunney JK, Kai C, Inumaru S, Onodera T.This special issue of Veterinary Immunology and Immunopathology summarizes the Proceedings of the 9th International Veterinary Immunology Symposium (9th IVIS) held August 2010, in Tokyo, Japan. Over 340 delegates from 30 countries discussed research progress analyzing the immune systems of numerous food animals and wildlife, probing basic immunity and the influence of stress, genetics, nutrition, endocrinology and reproduction. Major presentations addressed defense against pathogens and alternative control and prevention strategies including vaccines, adjuvants and novel biotherapeutics. A spe...
Nohejl T, Palkovicova J, Nesporova K, Valcek A, Lausova J, Dolejska M.The operon encoding short-chain fructooligosaccharide (scFOS) utilization enables bacteria of the family to grow and be sustained in environments where they would struggle to survive. Despite several cases of the detection of the operon in isolates of avian and equine origins, its global distribution in bacterial genomes remains unknown. The presence of the plasmid-harbored operon among resistant bacteria may promote the spread of antibiotic resistance. A collection of 11,538 antimicrobial-resistant isolates from various sources was screened for the gene encoding the scFOS transporter. O...
Kozlov DP.The problem of dissimilation of larvae of strongylates of ruminants in pasture biocoenosis is discussed. A new form of their migration in horizontal direction on the basis of negative geotaxis is suggested. As a result of alternation of vertical migration of larvae on the tilting leaves of the grass and their subsequent washing off with rain or dew down on the ground proceeds their distribution on the pasture. The description of corresponding experiments is given.
Bublot M.Until recently, Influenza was considered as a veterinary problem in avian, swine and horse only. New influenza strains able to infect and cause a disease in dogs and cats emerged these last six years. The most widely used influenza veterinary vaccines are the inactivated adjuvanted vaccines which are based on whole or split virus. New technologies have allowed the development of new generation vaccines including modified-live and vector vaccines. Modified-live influenza vaccines are available for horses only but they are in development in other species. Vector vaccines are already in use in ch...
Pelkola K, Heinikainen S, Pohjanvirta T.In Finland, Taylorella equigenitalis, the causative agent of contagious equine metritis (CEM), was first detected in 1992. The aim of this study was to genotype Finnish T. equigenitalis isolates to investigate the epidemiology of the infection in the Finnish horse population. A total of 34 T. equigenitalis isolates from 24 horses obtained during 1992-2021 were subjected to whole genome sequencing (WGS) and subsequent local ad hoc core genome multi-locus sequence typing (cgMLST) targeting 1259 loci. Classical MLST profiles were extracted from the whole-genome sequence data. Three novel MLST ty...
Ledermann W.With the apparition of the crazy cows disease at the end of twentieth century, great was the temptation for denominate "crazy horses disease" an ancient enzootic encephalo-myelitis, known from the 17th century and now named "Borna disease" in 1970, because severe outbreaks affecting horses in this city of Germany since 1885. But the sickness was not a prion disease but a viral one, causing also encephalopathy in several other animal species. After seventy years of investigation, the finding of the virus in human patients with psychiatric pathology in the eighties gave an incentive to work hard...
Touratier L.There is increasing interest in many parts of the world in trypanosomoses other than those transmitted by tsetse flies, as shown by numerous research projects and field studies. The refinement of techniques for studying the behaviour of trypanosomes (techniques of molecular biology) in axenic culture or in the parasitised host has led to progress in diagnosis and immunology, and a rational approach to chemotherapy and chemoprophylaxis of these infections. Field trials of enzyme-linked immunosorbent assays in Africa, Asia and South America have shown that these tests may now be regarded as reli...
Timoney PJ, Dillon PB, Geraghty VP, McArdle JF.Aspects of experimental transmission of the causal bacterium of contagious equine metritis (CEM) to albino Swiss mice were investigated. Whereas infection was established in the majority of female mice, the organism was recovered from only a limited number of male mice after challenge. No clinical evidence of infection was observed in the experimental mice. There was only one instance of presumptive venereal transmission of the CEM bacterium. One third of infected females conceived and had normal litters.
Petrucciani A, Yu G, Ventresca M.Eastern Equine Encephalitis (EEE) is an arbovirus that, while it has been known to exist since the 1930's, recently had a spike in cases. This increased prevalence is particularly concerning due to the severity of the disease with 1 in 3 symptomatic patients dying. The cause of this peak is currently unknown but could be due to changes in climate, the virus itself, or host behavior. In this paper we propose a novel multi-season deterministic model of EEE spread and its stochastic counterpart. Models were parameterized using a dataset from the Florida Department of Health with sixteen years of ...
Becker W.From 1981 until 1987 we investigated the more detailed circumstances regarding a prophylactic vaccination in altogether 37 stud farms with a history of virus abortion. In 23 cases, in which Prevaccinol and/or Resequin were used, it was found that the following of vaccination schedule and necessary immunization programmes respectively, had considerable imperfections. In seven cases prophylactic vaccinations were not carried out or corresponding questionnaires were not answered. The fact that in the present data no case of virus abortion was observed, when the mare was vaccinated according to th...
Tåmová B, Stumpa A, Zakopal J, Vĕzníková D, Mensík J.Equine influenza occurred in Czechoslovakia 14 years after the last epizootic in horses that had returned from abroad. Six strains A (Heq1Neq1) antigenically related to, but not identical with, strain A/eq/Praha/56 were isolated from 10 washings. Seroconversion was demonstrated with paired sera, but the antibody increase was more marked against the newly isolated strain.
Anandu S, Tanuj GN, Vijayasarathi MK, Manjusha KM, Samanta S, Bandyopadhyay S, Sankar M.Ocular setariasis is an ectopic infection caused by a parasite under the genus Setaria. Adult worms belong to the Setariidae family and typically reside in the peritoneal cavity of ungulates. However, immature forms of these species may aberrantly migrate to the eyes of cattle, buffalo, goats, horses and several other hosts, leading to corneal opacity and blindness. Here, we have distinguished the Setaria digitata collected from both equine and buffalo hosts based on the morphology, molecular profiling of mitochondrial cytochrome c oxidase subunit 1 (Cox1), cytochrome c oxidase subunit 3 (Cox3...
Maeda M, Abe M, Aoshima K, Kobayashi A, Fukushi H, Kimura T.Equine herpesvirus-1 (EHV-1) causes respiratory diseases, abortion, and encephalomyelitis in horses. The EHV-1 immediate-early (IE) protein, essential for viral replication, is transactivated by the binding of a multiprotein complex including the open reading frame 12 (ORF12) and some host factors to the IE promoter region. Promoter-associated non-coding RNAs (pancRNAs), which are transcribed from bidirectional promoters, regulate the transcription of neighboring genes in mammals and pathogens. In this study, we identified a novel pancRNA transcribed from across the areas of the 5'-untranslate...
Kannekens-Jager MM, Duim B, der Graaf-van Bloois LV, Zomer AL, Broekhuizen-Stins MJ, Boswinkel M, Wagenaar JA, Broens EM.In 2020 and 2022, nine cases of surgical site infections with a methicillin-resistant Staphylococcus aureus (MRSA) were diagnosed in horses in an equine referral clinic. Sixteen isolates (horses, n=9; environment, n=3; and staff members, n=4) were analysed retrospectively using Nanopore whole-genome sequencing to investigate the relatedness of two suspected MRSA outbreaks (2020 and 2022). The MRSA isolates belonged to ST398 and ST612. ST398 genomes from 2020 and 2022 formed three phylogenetic clusters. The first ST398 cluster from 2020 consisted of isolates from five horses and one staff membe...
Papouskova A, Drabkova Z, Brajerova M, Krutova M, Cizek A, Tkadlec J.We performed a retrospective analysis of MRSA isolates collected at the university equine clinic including clinical isolates from 2008 to 2021 and screening environmental, equine and personnel isolates from 2016. Screening and clinical samples were cultured on Brilliance MRSA 2 and Columbia agar (Oxoid), respectively, with enrichment for environmental samples. Antimicrobial susceptibility was assessed by disc diffusion. All the isolates were characterized by spa typing. Eighteen selected isolates were subjected to WGS with subsequent wgMLST clonal analysis. Among 75 MRSA isolates, five spa typ...
