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.
Durand JP, Simon F, Tolou H.West Nile virus (WNV) is a common arbovirosis, transmitted by mosquitoes mainly Culex. WNV is commonly responsible for equine epizootics and epidemics in humans in sub-Saharan Africa. It has been occasionally described in Southern Europe and in some Mediterranean countries. Since 1994, WNV clinical aspects seem to change with an increase of central neurological involvement and a higher mortality, especially among people older than 50 years. In 1999, WNV reached New York, being responsible for severe clinical manifestations. It spread all over North America in less than four years Four (only fo...
Minke JM, Audonnet JC, Fischer L.The increasing international movement of horses combined with the relaxation of veterinary regulations has resulted in an increased incidence of equine infectious diseases. Vaccination, along with management measures, has become the primary method for the effective control of these diseases. Traditionally modified live and inactivated vaccines have been used and these vaccines have proven to be very successful in preventing disease. However, there are a number of equine infectious diseases for which conventional technology has shown its limitations. The advent of recombinant technology has sti...
Ward MP, Levy M, Thacker HL, Ash M, Norman SK, Moore GE, Webb PW.To describe an outbreak of encephalomyelitis caused by West Nile virus (WNV) in horses in northern Indiana. Methods: Case series. Methods: 170 horses. Methods: Horses with clinical signs suggestive of encephalomyelitis caused by WNV were examined. Date, age, sex, breed, and survival status were recorded. Serum samples were tested for anti-WNV antibodies, and virus isolation was attempted from samples of brain tissue. Climate data from local weather recording stations were collected. An epidemic curve was constructed, and case fatality rate was calculated. Results: The most common clinical sign...
Castillo-Olivares J, Wood J.West Nile virus (WNV) is a flavivirus closely related to Japanese encephalitis and St. Louis encephalitis viruses that is primarily maintained in nature by transmission cycles between mosquitoes and birds. Occasionally, WNV infects and causes disease in other vertebrates, including humans and horses. West Nile virus has re-emerged as an important pathogen as several recent outbreaks of encephalomyelitis have been reported from different parts of Europe in addition to the large epidemic that has swept across North America. This review summarises the main features of WNV infection in the horse, ...
Daly JM, Newton JR, Mumford JA.Influenza A viruses of the H3N8 subtype are a major cause of respiratory disease in horses. Subclinical infection with virus shedding can occur in vaccinated horses, particularly where there is a mismatch between the vaccine strains and the virus strains circulating in the field. Such infections contribute to the spread of the disease. Rapid diagnostic techniques are available for detection of virus antigen and can be used as an aid in control programmes. Improvements have been made to methods of standardising inactivated virus vaccines, and a direct relationship between vaccine potency measur...
Singh BR, Singh VP, Agarwal M, Sharma G, Chandra M.Haemolysin patterns of 175 strains of different Salmonella enterica subspecies enterica serovars isolated from different animal sources and places were determined using 11 different blood agar media made with either non-washed horse/sheep erythrocytes or with washed erythrocytes of cattle, sheep, horse, goat, rabbit, guinea pig, and human A, O and B blood groups. Study on 47 strains belonging to 10 serovars of Salmonella from buffalo meat (buffen), 42 strains of 11 serovars from goat meat (chevon): 16 strains of Salmonella enterica serovar Paratyphi B and 25 of S. enterica serovar Paratyphi B ...
Waldridge BM, Wenzel JG, Ellis AC, Rowe-Morton SE, Bridges ER, D'Andrea G, Wint R.A prospective study was performed to determine the serologic response of previously vaccinated horses to revaccination against eastern and western equine encephalomyelitis (EEE and WEE). Horses responded variably to each antigen, and some horses had low or undetectable antibodies 6 months after vaccination. Some horses did not develop increasing titers to EEE or WEE despite recent vaccination. Geometric mean titers peaked 2 weeks after revaccination and were significantly increased from before revaccination. Except for one horse, EEE:WEE titer ratios ranged from 0.25 to 2.0. Regular vaccinatio...
Sebastian M, Gantz MG, Tobin T, Harkins JD, Bosken JM, Hughes C, Harrison LR, Bernard WV, Richter DL, Fitzgerald TD.During 2001, central Kentucky experienced acute transient epidemics of early and late fetal losses, pericarditis, and unilateral endophthalmitis, collectively referred to as mare reproductive loss syndrome (MRLS). A toxicokinetic/statistical analysis of experimental and field MRLS data was conducted using accelerated failure time (AFT) analysis of abortions following administration of Eastern tent caterpillars (ETCs; 100 or 50 g/day or 100 g of irradiated caterpillars/day) to late-term pregnant mares. In addition, 2001 late-term fetal loss field data were used in the analysis. Experimental dat...
den Boon S, Schellekens JF, Schouls LM, Suijkerbuijk AW, Docters van Leeuwen B, van Pelt W.To obtain detailed information about the current geographical distribution and incidence of tick bites and Lyme borreliosis in the Netherlands and to identify regional differences in the ecological risk factors that might be involved. Methods: Retrospective questionnaire study. Methods: All Dutch general practitioner's (GP) practices. Methods: In April 2002, all GPs in the Netherlands were asked to complete a short questionnaire on the number of cases of tick bites and erythema migrans seen in 2001 and the size of their practice. Associations with possible risk factors were determined at the m...
Webb BA, Barney WE, Dahlman DL, DeBorde SN, Weer C, Williams NM, Donahue JM, McDowell KJ.A new equine abortigenic disease, mare reproductive loss syndrome (MRLS), was recognized and significantly impacted the Ohio Valley in the springs of 2001 and 2002. MRLS caused approximately 330 million US dollars in losses in 2001. An epidemiological investigation of MRLS associated occurrence of the disease with exposure to eastern tent caterpillars (M. americanum). This work investigates the epidemiological association between M. americanum and MRLS to determine if this association was correlative or causative. A pilot study and simulated exposure to M. americanum and their excreta on pastu...
Romi R, Pontuale G, CIufolini MG, Fiorentini G, Marchi A, Nicoletti L, Cocchi M, Tamburro A.In the late summer of 1998, an outbreak of equine encephalomyelitis due to West Nile virus (WNV) occurred in the Tuscany region of central Italy. The disease was detected in 14 race horses from nine localities in four Provinces: Firenze, Lucca, Pisa and Pistoia. The outbreak area included Fucecchio wetlands (1800 ha), the largest inland marsh in Italy, and the adjacent hilly Cerbaie woodlands with farms breeding horses. To detect potential vectors of WNV, entomological surveys of Fucecchio and Cerbaie were undertaken during 1999-2002 by collecting mosquito larvae from breeding sites and adult ...
Zablotskij VT, Georgiu C, de Waal T, Clausen PH, Claes F, Touratier L.During its 20th annual meeting in Paris in May 1999, the OIE (World organisation for animal health) Ad Hoc Group on Non-Tsetse Transmitted Animal Trypanosomoses expressed the following concerns about dourine: the discrepancies in some of the results of the complement fixation test (CFT), which is the only international diagnostic test officially recognised by the International Organisation for the Transportation of Equidae; the persistence of suspected cases of dourine in some Asian, European and African countries; the impossibility of differentiating Trypanosoma equiperdum from Trypanosoma ev...
Archer DC, Freeman DE, Doyle AJ, Proudman CJ, Edwards GB.To determine whether there was an association between a history of cribbing and epiploic foramen entrapment (EFE) of the small intestine in horses. Methods: Retrospective study. Methods: 68 horses examined at the University of Illinois or the University of Liverpool veterinary teaching hospitals. Methods: For horses examined at the University of Illinois that underwent surgery because of strangulating small intestine lesions, information about cribbing was obtained through telephone calls with owners. For horses examined at the University of Liverpool that underwent surgery for colic for any r...
Zeller HG, Schuffenecker I.West Nile (WN) virus is a mosquito-transmitted flavivirus. It is widely distributed in Africa, the Middle East, Asia, and southern Europe and was recently introduced to North America. Birds are involved in the cycle of transmission as amplifying hosts. Humans and horses are considered accidental dead-end hosts. WN fever was initially considered a minor arbovirosis, usually inducing a nonsymptomatic or a mild flu-like illness in humans, but some cases of encephalitis associated with fatalities were reported in Israel in the 1950s. After two silent decades, several human and equine outbreaks of ...
Huang X, Xuan X, Xu L, Zhang S, Yokoyama N, Suzuki N, Igarashi I.An immunochromatographic test (BeICT) for the rapid detection of antibodies against Babesia equi was developed. It clearly differentiated B. equi-infected horses from B. caballi-infected and uninfected horses. The agreement with enzyme-linked immunosorbent assay results was 96.7% in the detection of field sera. The results suggest that BeICT is rapid, simple, reliable, and suitable for use to detect B. equi infection in the field.
Chabchoub A, Landolsi F, Zientara S, Amira A, Mejri M, Ghorbel A, Ghram A.The authors describe an equine influenza epizootic that occurred in Tunisia during February and March 1998 in the regions of Tozeur, Sousse and Tunis. They relate the symptoms, the different stages of diagnosis and the serological results.
PospÃsil L.Glanders (malleus), attacking equids and transmissible to humans, does not occur in our geographical area any more, but world-wide eradication has not yet been achieved. Cases of glanders have been reported from India, Iraq, Mongolia and China and in 2001 also from South America. The disease is caused by Burkholderia mallei (earlied known as Bacillus, Pfeiferella, Loefflerella, Malleomyces, Actinobacillus, or Pseudomonas mallei). The continual interest of microbiologists in the causative agents indicates that glanders cannot be regarded as a closed historic episode. Occupational infections of ...
Özçelik R, Graubner C, Remy-Wohlfender F, Dürr S, Faverjon C.Equine health is important in regard to trade, economy, society, and the veterinary, as well as public health. To reduce the burden of equine infectious diseases internationally, it is important to collect, review, and distribute equine health surveillance data as accurate and timely as possible. Within this study, we aimed at providing a comprehensive descriptive analysis of data submitted to Equinella, a voluntary veterinary-based surveillance system of non-notifiable equine infectious diseases and clinical signs, in Switzerland. This was achieved by reviewing the reports submitted since its...
Harris PA.The paper provides some basic epidemiological and clinical descriptive information for the equine rhabdomyolysis syndrome (ERS) in the United Kingdom. Information was obtained retrospectively from laboratory submission data as well as cases investigated by the author via their veterinary surgeon. Sex appeared to be a significant variable, with females being more likely than males to suffer from ERS compared to other conditions (P less than 0.01). More samples were submitted in the period November-February than at other times of the year (P less than 0.01). The condition appeared to be found in...
Greene EA, Hein W, Wickens CL, Smarsh DN.The COVID-19 pandemic and resulting stay-at-home directives, adopted out of necessity to protect human health, introduced significant challenges for horse owners and small equine businesses. Restricted access, and in many cases closure of barns, resulted in a multitude of questions and concerns within the equine community which needed to be addressed rapidly. Extension Horses, Inc. (EH) coordinated the development and delivery of a variety of educational resources utilizing a combination of online formats and dissemination through social media and EH member contact lists. A series of infograph...
Huang BF, Kropinski AM, Bujold AR, MacInnes JI.Actinobacillus equuli subsp. equuli is a member of the family Pasteurellaceae that is a common resident of the oral cavity and alimentary tract of healthy horses. At the same time, it can also cause a fatal septicemia in foals, commonly known as sleepy foal disease or joint ill disease. In addition, A. equuli subsp. equuli has recently been reported to act as a primary pathogen in breeding sows and piglets. To better understand how A. equuli subsp. equuli can cause disease, the genome of the type strain of A. equuli subsp. equuli, ATCC 19392(T), was sequenced using the PacBio RSII sequencing s...
Gibbons DF.Salmonellosis in Equidae occurs sporadically throughout the world; the incidence recorded ranges from less than 1 per cent to as much as 27 per cent. In 1976 there was a significant increase in disease and mortality caused by salmonellosis in horses in Britain and treatment was less successful than with other species. Data revealed a general progressive shift away from species specific salmonella serotypes towards the ubiquitous but less discerning strains of Salmonella typhimurium. The role of predisposing causes is assessed and treatment, prevention and zoonitic importance commented upon.
Aradaib IE.A nested reverse transcriptase (RT) polymerase chain reaction (RT-PCR), for rapid detection of African horse sickness virus (AHSV) double-stranded ribonucleic acid (dsRNA) in cell culture and tissue samples, was developed and evaluated. Using an outer pair of primers (P1 and P2), selected from genome segment three of AHSV serotype 6 (AHSV-6), the RT-PCR-based assay resulted in amplification of a 890 base pair (bp) primary PCR product. RNAs from the nine vaccine strains of AHSV, and a number of AHSV field isolates including the Central African isolates of AHSV-9 and AHSV-6, propagated in cell c...
Tantaoui-Elaraki A, Mekouar SL, el Hamidi M, Senhaji M.From 10 moldy straw samples collected in a Moroccan area with an apparent equine stachybotryotoxicosis outbreak in November 1991, 8 isolates of Stachybotrys atra were obtained. They all showed toxigenesis, however they were variable in nature and intensity. While 1 isolate had only mild toxicity when fed to mice as moldy barley, another revealed very high toxicity to Artemia saline larvae, or rat skin, and to mice. The toxicity of the other 6 isolates were between these 2 limits. This study indicates that the November 1991 outbreak was due to toxigenic strains of Stachybotrys atra.
Newton JR, Wood JL, Castillo-Olivares FJ, Mumford JA.Serological analysis of blood samples submitted to the Animal Health Trust showed that during 1995, 185 of 9203 unvaccinated horses (2.0 per cent) tested positive for antibodies to equine arteritis virus (EAV), and that during 1996, 46 of 8851 unvaccinated horses (0.52 per cent) tested positive. During both years thoroughbreds were the predominant breed tested and only a small proportion of these (<0.3 per cent), consisting predominantly of imported mares, were seropositive. In contrast, among standardbred horses, from which samples were actively solicited in 1995, 84 of 454 (18.5 per cent) we...
Oliveira-Filho JP, Cagnini DQ, Badial PR, Pessoa MA, Del Piero F, Borges AS.Cassia occidentalis is a bush from the Leguminosae family, subfamily Caesalpinoideae, and is a toxic plant of veterinary interest due to the occasional contamination of animal rations. This report describes the clinical and histopathological findings of an outbreak of C. occidentalis poisoning in horses. Twenty mares were poisoned after consuming ground corn contaminated with 8% of C. occidentalis seeds. Of the 20 animals affected, 12 died: 8 mares were found dead, 2 died 6 h after the onset of clinical signs compatible with hepatic encephalopathy and the 2 other animals were subjected to euth...
Equine infectious anaemia (EIA) is a disease with an almost worldwide distribution, with several outbreaks having been reported recently in European countries. In Italy, two regions, Lazio and Abruzzo, are considered as endemic areas for this disease. In nature, the EIA virus is mechanically transmitted by biting flies such as tabanids (Diptera: Tabanidae), although few studies have investigated the epidemiological implications. In the present study, several sites characterized by different levels of EIA prevalence were sampled. In sites with high tabanid populations, a seasonal succession of ...
Yıldırım Y, Yılmaz V, Yazıcı K, Öziç C, Ozkul A, Çağırgan AA.West Nile virus (WNV), a member of the Flaviviridae, is a major arbovirus that causes West Nile fever. Previous data showed the prevalence of the WNV serologically and molecular in Turkey, and the presence of lineage 1 in horses and humans has been reported. This is the first notification of partial phylogeny of WNV detected in donkeys in the northeast of Turkey (on the Iranian border). Blood serum samples collected from 25 donkeys without clinical symptoms were tested by RT-PCR. Sequence analysis of the sample detected as positive was performed. Multiple sequence alignments of reference seque...
Khrustaleva TA, Khrustalev VV, Barkovsky EV, Kolodkina VL, Astapov AA.The SF23 peptide corresponding to the receptor binding fragment of diphtheria toxin (residues 508-530) has been synthesized. This fragment forming a protruding beta hairpin has been chosen because it is the less mutable B-cell epitope. Affine chromatography and ELISA show that antibodies from the sera of persons infected by toxigenic Corynebacterium diphtheriae and those immunized by diphtheria toxoid are able to bind the synthetic SF23 peptide. There are antibodies recognizing the SF23 peptide in the serum of horses hyperimmunized with diphtheria toxoid. Analysis of circular dichroism spectra...
Bryans JT, Hendricks JB.Contagious equine metritis, introduced by importation of 2 comtaminated stallions from France, affected 54 Thoroughbred brood mares during the 1978 breeding season in Kentucky. The infection was diagnosed bacteriologically and by the use of a complement fixation test. Although lateral spread to stallions, and probably to a few mares, occurred through human agency in the breeding sheds of 2 stud farms, control measures instituted early in the epidemic confined the disease to brood mares bred by stallion on only these farms.
Hooper PT.Severe spongy degeneration of the central nervous system (CNS) was seen in 11 cattle, 19 sheep, 4 pigs and 1 goat, associated with a variety of hepatic diseases, particularly those caused by hepatotoxic pyrrolizidine alkaloids. It was also seen in a milder form in 2 of 8 horses examined, 1 dog of 5 dogs examined, and in 1 rabbit only of a large number of laboratory animals examined. This paper reports results of experiments which confirmed initially that the CNS disease cold be caused by pyrrolizidine alkaloid intoxication. This was done by poisoning lambs with lasiocarpine. As the disease was...
Dong J, Liu G, Gao N, Suo J, Matthijnssens J, Li S, Yuan D, Du Y, Zhang J, Yamashita N, Haga T, Cook FR, Zhu W.In contrast to horses, the only evidence suggesting gastrointestinal disease in neonatal donkeys is associated with Group A rotaviruses (RVAs) is the detection of viral antigens by ELISA in just 1 of 82 symptomatic donkey foals. No additional, more comprehensive investigations have been conducted, and RVAs if circulating in donkey populations have not been molecularly characterised. Objective: To investigate if RVAs are associated with an outbreak of severe enteritis in neonatal donkeys and if associated determine the genotype(s) along with the phylogenetic relationship to RVA strains circulat...
Blackburn NK, Swanepoel R.During the nine years from October 1972 to September 1981 African horse sickness (AHS) virus was isolated from 23 suspected cases of the disease in Zimbabwe and complement fixation antibody titres indicative of recent infection were detected in a further 49 horses. The 23 isolations belonged to seven of the nine known serotypes of AHS virus. In response to a questionnaire in 1980 the owners of 20% (1,654/8,000) of the horses in Zimbabwe indicated that they had recorded 207 cases of clinically diagnosed AHS with 107 deaths from 1975 to 1980. Fifty-six cases with 50 deaths had occurred in foals ...
McDonough PL, Shin SJ, Timoney JF.The salmonella serotypes isolated during 1978 to 1983 at the diagnostic and clinical laboratories of the New York State College of Veterinary Medicine from animal sources in New York state were reviewed and compared to earlier data from New York state animals and to national data for both human and animal sources. A total of 255 salmonella strains were studied from the six year period and included 33 serotypes. Salmonella enteritidis ser Typhimurium continued to be the most commonly reported serotype followed by serotype Anatum. Generally serotypes from New York state animals reflected nationa...
Malbon AJ, Dürrwald R, Kolodziejek J, Nowotny N, Kobera R, Pöhle D, Muluneh A, Dervas E, Cebra C, Steffen F, Paternoster G, Gerspach C, Hilbe M.Borna disease (BD), a frequently fatal neurologic disorder caused by Borna disease virus 1 (BoDV-1), has been observed for decades in horses, sheep, and other mammals in certain regions of Europe. The bicoloured white-toothed shrew (Crocidura leucodon) was identified as a persistently infected species involved in virus transmission. Recently, BoDV-1 attracted attention as a cause of fatal encephalitis in humans. Here, we report investigations on BoDV-1-infected llamas from a farm in a BD endemic area of Switzerland, and alpacas from holdings in a region of Germany where BD was last seen in the...
Norred WP, Voss KA.Fumonisins are secondary metabolites of Fusarium moniliforme , Fusarium proliferatum and several other Fusaria that commonly contaminate corn. Only recently discovered in 1988, these mycotoxins appear to be the causative agents of several toxicoses in animals that result from ingestion of moldy corn or corn-based feeds. The syndromes observed vary considerably among the different species affected and include brain lesions in equids, lung edema in swine, and nephrotoxicity, hepatotoxicity and hepatocellular carcinoma in laboratory rats. There is also evidence that suggests that F. moniliforme a...
Cook BR.Twenty-five years ago Williams and Sweatman suggested that in Great Britain there are two subspecies of Echinococcus granulosus--E. granulosus granulosus and E. granulosus equinus. Echinococcus granulosus granulosus does not mature either in foxes or in horses: E. granulosus equinus will mature in either. The prepatent period of E. granulosus granulosus in the definitive host is about 42 days while that of E. granulosus equinus is about 70 days. Each subspecies has a characteristic morphology. More recently, in the course of seven experiments, dogs, red foxes (Vulpes vulpes crucigera), arctic ...
Liebenberg D, van Hamburg H, Piketh S, Burger R.Africa horse sickness (AHS) is a lethal disease of horses with a seasonal occurrence that is influenced by environmental conditions that favor the development of Culicoides midges (Diptera: Ceratopogonidae). This study compared and evaluated the relationship of various modeled climatic variables with the distribution and abundance of AHS in South Africa and Namibia. A comprehensive literature review of the historical AHS reported data collected from the Windhoek archives as well as annual reports from the Directorate of Veterinary services in Namibia were conducted. South African AHS reported ...
Kumar R, Patil RD.The importance of horse (Equus caballus) to equine practitioners and researchers cannot be ignored. An unevenly distributed population of equids harbors numerous diseases, which can affect horses of any age and breed. Among these, the affections of nervous system are potent reason for death and euthanasia in equids. Many episodes associated with the emergence of equine encephalitic conditions have also pose a threat to human population as well, which signifies their pathogenic zoonotic potential. Intensification of most of the arboviruses is associated with sophisticated interaction between ve...
Tamamura-Andoh Y, Niwa H, Kinoshita Y, Uchida-Fujii E, Arai N, Watanabe-Yanai A, Iwata T, Akiba M, Kusumoto M.Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae have become a cause for great concern. Although some studies have reported the prevalence of ESBL-producing bacteria and ESBL-encoding genes in horses worldwide, the genetic structure surrounding the ESBL gene has not been analysed in detail. In the present study, we isolated two ESBL-producing Escherichia coli strains from diseased racehorses in Japan and demonstrated the mechanisms underlying the acquisition of their antimicrobial resistance (AMR) genes. Two ESBL-producing E. coli strains (E148 and E189) were isolated from th...
Finno CJ, Kaese HJ, Miller AD, Gianino G, Divers T, Valberg SJ.A pigment retinopathy has been reported in adult horses with equine motor neuron disease (EMND) arising from chronic α-tocopherol (α-TP) deficiency. A pigment retinopathy has not been identified in horses with neuroaxonal dystrophy/equine degenerative myeloencephalopathy (NAD/EDM) that affects genetically susceptible young horses with α-TP deficiency. The objective of this report is to describe, for the first time, a pigment retinopathy in a family of α-TP-deficient Warmbloods (WB) with clinically apparent NAD/EDM or EMND. Unassigned: Twenty-five WB horses from one farm underwent complete ...
Hasan SS, Dey D, Singh S, Martin M.Alphaviruses are arboviruses that cause arthritis and encephalitis in humans. Eastern Equine Encephalitis Virus (EEEV) is a mosquito-transmitted alphavirus that is implicated in severe encephalitis in humans with high mortality. However, limited insights are available into the fundamental biology of EEEV and residue-level details of its interactions with host proteins. In recent years, outbreaks of EEEV have been reported mainly in the United States, raising concerns about public safety. This review article summarizes recent advances in the structural biology of EEEV based mainly on single-par...
