Infectious diseases in horses encompass a range of illnesses caused by bacteria, viruses, fungi, or parasites. These diseases can affect various systems within the equine body, leading to symptoms that range from mild discomfort to severe systemic illness. Common infectious diseases in horses include equine influenza, strangles, equine herpesvirus, and West Nile virus. These diseases can be transmitted through direct contact with infected animals, contaminated surfaces, or vectors such as insects. Understanding the mechanisms of transmission, pathogenesis, and immune response is essential for effective prevention and control. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, diagnosis, treatment, and management of infectious diseases in horses.
Yamanaka T, Tsujimura K, Kondo T, Matsumura T, Ishida H, Kiso M, Hidari KI, Suzuki T.Equine H3N8 influenza A viruses (EIVs) cause respiratory disease in horses and circulate among horses worldwide. In 2004, an outbreak of canine H3N8 influenza A virus (CIV) occurred among dogs in Florida and has spread among dogs in the United States (US). Genetic analyses revealed that this CIV is closely related to the recent EIVs. Although CIV-infected dogs could be the source of H3N8 influenza A virus for horses, it remains unclear whether the CIV circulating in the United States still maintains its infectivity and/or pathogenicity in horses. To address this, we investigated the infectivit...
Gildea S, Arkins S, Cullinane A.In Ireland, horses may be protected against equine influenza virus (EIV) as a result of natural exposure or vaccination. Current mandatory vaccination programmes are targeted at highly mobile horses. A correlation between antibody levels as measured by single radial haemolysis (SRH) and protective immunity against EIV has been established. Objective: The objective of this study was to determine the susceptibility of selected populations of horses by quantifying their antibodies to EIV. Methods: Blood samples were collected from Thoroughbred weanlings, yearlings, racehorses and broodmares, teas...
Morens DM, Taubenberger JK.To understand human influenza in a historical context of viral circulation in avian species, mammals, and in the environment. Methods: Historical review. Methods: Global events in a variety of circumstances over more than 3,000 years time. Methods: Comprehensive review of the historical literature including all major publications on pandemic and panzootic influenza. Methods: Influenza pandemics, panzootics, major epidemics and epizootics, and instances of interspecies transmission of influenza A. Results: Extensive documentation of human and animal influenza over many centuries suggests that i...
Georges KC, Ezeokoli CD, Sparagano O, Pargass I, Campbell M, D'Abadie R, Yabsley MJ.Equine piroplasmosis due to Theileria equi and Babesia caballi is endemic in Trinidad. A case of equine piroplasmosis due to T. equi was diagnosed in a thoroughbred foal at 10h post-partum. A high parasitaemia (63%) of piroplasms was observed in a Wright-Giemsa(®) stained thin blood smear from the foal. In addition, the 18S rRNA gene for Babesia/Theileria was amplified from DNA extracted from the blood of the foal and the mare. Amplified products were subjected to a reverse line blot hybridization assay (RLB), which confirmed the presence of T. equi DNA in the foal. The mare was negative by R...
Carlson KL, Kuskie KR, Chaffin KM, Libal MC, Giguère S, Lawhon SD, Cohen ND.This study determined the antimicrobial activity of tulathromycin against Rhodococcus equi in vitro. Ninety-eight virulent isolates of R. equi from equine clinical cases were examined, of which 20 isolates were macrolide resistant. A custom 96-well antimicrobial susceptibility testing plate was used, allowing 14 additional antimicrobials to be tested against R. equi. Isolates were cultured with various concentrations of antimicrobials, and minimal inhibitory concentration (MIC) values were determined. Tulathromycin was found to have poor activity in vitro against R. equi isolates susceptible o...
Gürellı G, Göçmen B.Hemiprorodon gymnoposthium was investigated in the intestine of horses, found in Cyprus. It was found in four of fifth horses examined and thus had a frequency of appearence of 80%. This study reports for the first time the presence of Hemiprorodon gymnoposthium in the intestine of Equids in Cyprus. In addition, it is the second report from the world. Specimens were found to be similar to the original description on the basis of morphological characters and biometric data.
Pacheco RC, Moraes-Filho J, Guedes E, Silveira I, Richtzenhain LJ, Leite RC, Labruna MB.The present study was performed in an area endemic for Brazilian spotted fever (BSF) in Juiz de Fora, state of Minas Gerais, Brazil, during the years 2007 and 2008, when fatal cases of BSF (caused by Rickettsia rickettsii) were reported. Adult ticks (Acari: Ixodidae) identified as Rhipicephalus sanguineus (Latreille) and Amblyomma cajennense (Fabricius) were collected from dogs and horses, respectively, and tested by polymerase chain reaction (PCR). Overall, 13.1% of the Rh. sanguineus ticks and none of the A. cajennense were found to be infected with R. rickettsii. Two isolates of R. ricketts...
Gorman JK, Gabriel M, MacLachlan NJ, Nieto N, Foley J, Spier S.This pilot study evaluated protection of an equine autogenous bacterin-toxoid vaccine against Corynebacterium pseudotuberculosis infection. Twenty-four BALB/c mice were inoculated with two doses of bacterin-toxoid vaccine or two injections of a placebo. Clinical, microbiologic, and pathologic outcomes were assessed after intradermal infection with one of two equine-origin C. pseudotuberculosis strains. Mice receiving bacterin-toxoid from fast-growing C. pseudotuberculosis showed significant protection from challenge infection, as evidenced by a higher survival rate, fewer gross and histopathol...
Buzzell GR, Tariq S, Traversa D, Schuster R.The infective larva of the spirurid nematode Habronema muscae, a parasite of houseflies, was measured and specimens fixed in Karnovsky's fluid were examined by scanning electron microscopy. The oral opening contains six teeth and is surrounded by large bilobed dorsal and ventral lips and smaller lateral lips. A pair of amphids lie behind the lateral lips. There are two rows of four cephalic papillae. The body is deeply ridged, both transversely and longitudinally. The caudal end of the worm is studded by small papillae. The position of the anal opening is somewhat ambiguous. These larval morph...
Pauvolid-Corrêa A, Tavares FN, Costa EV, Burlandy FM, Murta M, Pellegrin AO, Nogueira MF, Silva EE.As in humans, sub-clinical infection by arboviruses in domestic animals is common; however, its detection only occurs during epizootics and the silent circulation of some arboviruses may remain undetected. The objective of the present paper was to assess the current circulation of arboviruses in the Nhecolândia sub-region of South Pantanal, Brazil. Sera from a total of 135 horses, of which 75 were immunized with bivalent vaccine composed of inactive Eastern equine encephalitis virus (EEEV) and Western equine encephalitis virus(WEEV) and 60 were unvaccinated, were submitted to thorough viral i...
Salvagni CA, Dagnone AS, Gomes TS, Mota JS, Andrade GM, Baldani CD, Machado RZ.Ehrlichiosis is a zoonotic disease caused by gram-negative and intracellular obligatory bacterial organisms. Equine Granulocytic Anaplasmosis - EGA (formerly Equine Granulocytic Ehrlichiosis, EGE) is a seasonal disease, normally self-limited in horses. There are few reports in Brazil about this ehrlichial agent, as well as its natural vectors. Nowadays, veterinarians are considering the suspicion of EGA in horses with suggestive symptoms of ehrlichiosis and which do not respond to piroplasmosis treatment. The aim of the present study was to identify horses exposed to the agent A. phagocytophil...
Clode AB.The following article briefly discusses the pathogenesis of infectious keratitis in the horse, followed by discussion of management and pharmacological aspects to be considered when devising a therapeutic protocol for affected patients.
Lowe RC.Uveitis in the equine population of the UK does not appear to be as prevalent or disastrous as seen across regions of Europe and the USA. Some cases perceived to be recurrent uveitis may be poorly resolved single episodes of uveitis and care should be taken not to make the diagnosis of recurrence without ensuring effective control of the initial episode. Leptospira spp. appear to play only a minor role ERU in the UK which is probably the main reason for the prevalence of the disease being much lower compared to the USA and mainland Europe. Actual data are relatively few on the ground as far as...
Adams AA, Sturgill TL, Breathnach CC, Chambers TM, Siger L, Minke JM, Horohov DW.Equine influenza virus is a leading cause of respiratory disease in the horse population; however, the susceptibility of old horses to EIV infection remains unknown. While advanced age in horses (>20 years) is associated with age-related changes in immune function, there are no specific recommendations regarding the vaccination of older horses even though a well-characterized effect of aging is a reduced antibody response to standard vaccination. Therefore, we evaluated the immunological and physiological response of aged horses to a live non-replicating canarypox-vectored EIV vaccine and s...
Han X, Zou J, Wang X, Guo W, Huo G, Shen R, Xiang W.The Chinese EIAV vaccine is an attenuated live-virus vaccine obtained by serial passage of a virulent horse isolate (EIAV(L)) in donkeys (EIAV(D)), and subsequently in donkey cells in vitro. In this study, we compare the env gene of the original horse virulent virus (EIAV(L)) with attenuated strains serially passaged in donkey MDM (EIAV(DLV)), and donkey dermal cells (EIAV(FDDV)). Genetic comparisons among parental and attenuated strains found that vaccine strains contained amino acid substitutions/deletions in gp90 that resulted in a loss of three potential N-linked glycosylation sites, desig...
Timoney PJ.Contagious equine metritis (CEM) has given rise to international concern since it was first recognized as a novel venereal disease of equids in 1977 and the etiologic agent was identified as a previously undescribed bacterium, Taylorella equigenitalis. Horse industry concerns over CEM centered on the ease with which this bacterium could be disseminated, the significance of T. equigenitalis as a cause of short-term infertility in the mare, and the existence of the carrier state in the stallion and the mare. The first known outbreak of CEM in the United States was in Kentucky in 1978. The econom...
David DE, Lynne AM, Han J, Foley SL.Escherichia coli has been used as an indicator organism for fecal contamination of water and other environments and is often a commensal organism in healthy animals, yet a number of strains can cause disease in young or immunocompromised animals. In this study, 281 E. coli isolates from bovine, porcine, chicken, canine, equine, feline, and other veterinary sources were analyzed by BOXA1R PCR and by virulence factor profiling of 35 factors to determine whether they had utility in identifying the animal source of the isolates. The results of BOXA1R PCR analysis demonstrated a high degree of dive...
Viana D, Blanco J, Tormo-Más MA, Selva L, Guinane CM, Baselga R, Corpa J, Lasa I, Novick RP, Fitzgerald JR, Penadés JR.Staphylococci adapt specifically to various animal hosts by genetically determined mechanisms that are not well understood. One such adaptation involves the ability to coagulate host plasma, by which strains isolated from ruminants or horses can be differentiated from closely related human strains. Here, we report first that this differential coagulation activity is due to animal-specific alleles of the von Willebrand factor-binding protein (vWbp) gene, vwb, and second that these vwb alleles are carried by highly mobile pathogenicity islands, SaPIs. Although all Staphylococcus aureus possess c...
Robin CA, Wylie CE, Wood JL, Newton JR.Detailed knowledge of horse populations can better facilitate effective control of equine diseases. Preliminary studies were undertaken to ascertain the type of information held on the UK's National Equine Database (NED) and to determine the geographical resolution at which mandatorily recorded owner addresses might be a suitable proxy for predicting horse locations. Results indicated that relatively few UK passport-issuing organisations requested details of where horses were kept in addition to owner address details. Examination of data on 1440 horses held on an Animal Health Trust syndromic ...
Venter M, Swanepoel R.West Nile virus (WNV) is widely distributed in South Africa, but since a few cases of neurological disease have been reported from this region, endemic lineage 2 strains were postulated to be of low virulence. Several cases of nonfatal encephalitis in humans as well as fatal cases in a foal, dog, and ostrich chicks have, however, been associated with lineage 2 WNV in South Africa. The pathogenesis of lineage 2 WNV strains was investigated using mouse neuroinvasive experiments, gene expression experiments, and genome sequence comparisons which indicated that lineage 2 strains that are highly pa...
Blanton JD, Palmer D, Rupprecht CE.During 2009, 49 states and Puerto Rico reported 6,690 rabid animals and 4 human rabies cases to the CDC, representing a 2.2% decrease from the 6,841 rabid animals and 2 human cases reported in 2008. Approximately 92% of reported rabid animals were wildlife. Relative contributions by the major animal groups were as follows: 2,327 (34.8%) raccoons, 1,625 (24.3%) bats, 1,603 (24.0%) skunks, 504 (75%) foxes, 300 (4.5%) cats, 81 (1.2%) dogs, and 74 (1.1%) cattle. Compared with 2008, numbers of rabid raccoons and bats that were reported decreased, whereas numbers of rabid skunks, foxes, cats, cattle...
Rola J, Larska M, Rola JG, Belák S, Autorino GL.The aim of the study was to determine the situation of equine arteritis virus (EAV) infections in hucul horses. A total of 176 horses (154 mares and 22 stallions) from the biggest hucul horse stud in Poland were tested. Antibodies against EAV were detected in 97 (55.1%) horses. The EAV seroprevalence among mares was 53.2% while in stallions - 68.2%. The percentage of positive mares increased with their age, thus amongst the mares of less than 2 years of age the percentage was 32.5%, while in the group of 3-5 years old increased to 59.4% and in the mares in the age of 6-10 years and older than ...
Marenzoni ML, Coppola G, Maranesi M, Passamonti F, Cappelli K, Capomaccio S, Verini Supplizi A, Thiry E, Coletti M.Equid herpesvirus 5 (EHV-5) infection was detected in a farm in Italy by the use of a semi-nested polymerase chain reaction (PCR) targeting glycoprotein B of EHV-5 on nasal swabs and blood samples of clinically healthy and randomly selected Lipizzaner horses (n = 55). Twenty-five horses at the age of 4-17 years and 30 at an age of 1-3 years were sampled once. The association of the infection with these age-groups and the gender of the horses was investigated. The apparent prevalence of EHV-5 infection was significantly different between age-cohorts: it was higher in the younger group of ...
Yeh JY, Lee JH, Seo HJ, Park JY, Moon JS, Cho IS, Lee JB, Park SY, Song CS, Choi IS.The aim of this study was to develop a highly sensitive and specific one-step duplex reverse transcriptase PCR (RT-PCR) assay for the simultaneous and differential detection of West Nile (WNV) and Japanese encephalitis (JEV) viruses. The bioinformatic analysis of published sequences of WNV and JEV revealed conserved regions not targeted by previously reported primers. A total of 13 primers were designed based on these regions to detect all of the WNV and JEV lineages and to discriminate between the two viruses by the generation of 482- and 241-bp cDNA products, respectively. The results indica...
Muzari MO, Burgess GW, Skerratt LF, Jones RE, Duran TL.Tabanid flies in Australia are potential vectors of the parasite Trypanosoma evansi which causes the animal disease surra. It is endemic to most of south-east Asia and could enter Australia, but evaluation of the potential impact of a surra incursion requires identification of the major hosts of Australian tabanids. This study investigated the natural pattern of feeding and host preference by tabanid flies of Townsville, north Queensland by identification of ingested blood in trap-caught tabanids using ELISA. The assays were developed for identification of horse, cow, macropod and pig blood me...
Liao D, Shen J.In the present article, we summarize our studies of antrycide-resistance of Trypanosoma brucei evansi in four aspects in the last recent several years, the analysis of quinapyramine-sensitive situation of T. b. evansi in China, biological characteristics of T. b. evansi population in quinapyramine-resistance and biological materials of quinapyramine-resistance in T. b. evansi population. Firstly, the correlative assays of effective dosage of quinapyramine on T. b. evansi disease between in vivo and in vitro methods showed that their relationship was parabolic with positive correlation. On the ...
Roberts D, Cotter HVT, Cubeta M, Gilger BC.To determine minimum inhibitory concentrations (MICs) of four fungal species isolated from horses presented with equine fungal keratitis (EFK) in the southeastern United States to previously untested azole, echinocandin, and carboxamide antifungal drugs. Methods: In vitro assays were performed to determine the susceptibility of Aspergillus flavus, A. fumigatus, Fusarium falciforme, and F. keratoplasticum to five antifungal drugs representing three modes of action. Results: Luliconazole exhibited increased growth inhibition against both Aspergillus and Fusarium compared to commonly used, stan...
Hierweger MM, Remy-Wohlfender F, Franzen J, Koch MC, Blau D, Schoster A, Nicholson P, Gerber V, Gurtner C, Fouché N, Unger L, Seuberlich T.Coronaviruses are causing severe respiratory and enteric diseases in humans and animals. Here, we report an outbreak of equine coronavirus disease in adult horses, detected by a voluntary syndromic surveillance scheme for equine diseases in Switzerland. This scheme allowed a rapid concerted action to diagnose and contain the disease.
Singh BR, Jyoti J, Chandra M, Babu N, Sharma G.Salmonellosis is a zoonosis, and one of the most serious public health and animal health problems. Methods: We studied 111 isolates of Salmonella belonging to 14 S. enterica subspecies enterica serovars namely S. Abortusequi (45), S. Weltevreden (1), S. Dumfries (2), S. Tshiongwe (1), S.I. 4,5,12:r,i:1,5 (12), S. Bovismorbificans (3), S. Drogana (8), S. Lagos (4), S. Kottbus (3), S. Richmond (1), S. Typhimurium (6), S. Newport (7), S. Paratyphi B var Java (17) and S. Saintpaul (5) isolated from equids in India. Results: All strains studied were resistant to one or more antimicrobials. Strains ...
Timoney JF, Mukhtar MM.The group C streptococci are the most commonly isolated bacteria from disease states in the horse. Important virulence factors of S. equi and S. zooepidemicus are the hyaluronic acid capsule and the antiphagocytic fibrillar M protein located on the surface of the cell wall and extending into and through the capsule. The hyaluronic acid capsule is non-antigenic and so is not involved in protective immunity. The M protein, a superantigen, elicits very strong B and T cell responses that may result in protective immunity mediated by opsonic antibodies in plasma and by locally synthesized IgG and I...
Schwartz EJ, Nanda S, Mealey RH.Lentivirus escape from neutralizing antibodies (NAbs) is not well understood. In this work, we quantified antibody escape of a lentivirus, using antibody escape data from horses infected with equine infectious anemia virus. We calculated antibody blocking rates of wild-type virus, fitness costs of mutant virus, and growth rates of both viruses. These quantitative kinetic estimates of antibody escape are important for understanding lentiviral control by antibody neutralization and in developing NAb-eliciting vaccine strategies.
Prescott JF, Hoffman AM.This article summarizes recent advances in understanding of the epidemiology, pathogenesis, clinical and laboratory diagnosis, immunology, treatment, and control of Rhodococcus equi infections in foals. Our understanding of these aspects currently is sufficient to ensure control of this problem on affected farms and in infected foals. More information, however, is needed on factors predisposing foals to R. equi pneumonia, in particular, the nature of the naturally occurring cellular immunodeficiency in foals of 2 to 4 months of age, which also predisposes them to severe respiratory infection w...
Madison JB, Reid BV, Raskin RE.Infectious arthritis caused by Candida spp was diagnosed in 2 horses. Source of infection was by direct inoculation in 1 horse and was presumed to be hematogenous in the other horse. On microbial culturing of synovial fluid and synovial membrane specimens, the organisms were isolated in both horses. In both horses, the joint infections resolved after i.v. administration of amphotericin B and joint drainage; however, 1 horse was eventually euthanatized because of signs of cervical pain and progressively worsening ataxia. Fungal organisms isolated on microbial culturing of joint specimens in hor...
Stasiak K, Dunowska M, Rola J.Equid herpesvirus 1 (EHV-1) infections are endemic worldwide, including Poland. Many are subclinical, but some are associated with respiratory disease, abortion, neonatal foal death, or neurological disease. We describe an outbreak of abortions in Arabian mares at a well-managed State stud farm in Poland. Methods: Eight of 30 pregnant mares aborted and one gave birth to a weak foal that died within 72 h after birth. EHV-1 was isolated from all fetuses as well as from the diseased foal. All viruses belonged to the N variant based on the predicted open reading frame (ORF) 30 amino acid sequenc...
Negash W, Erdachew Y, Dubie T.In Ethiopia, equines serve in traction power, carting, recreation, festival packing, riding, transportation, and other activities since time immemorial. Strongyles are common equine health problems in Ethiopia though research based data on equine strongyles are limited particularly in the study areas, in and around Mekelle city. Therefore, the present study was intended to estimate the prevalence of common equine strongyles in and around Mekelle city from November 2018 to April 2019 and to assess risk factors associated with infection of strongyle parasites as well. Cross sectional design was ...
Byars TD, Becht JL.The historical, clinical, diagnostic, and therapeutic aspects of pleuropneumonia are reviewed with emphasis placed on aggressive treatment and ultrasound diagnosis. The common sequelae are described, and appropriate treatment recommendations are included. A favorable prognosis may be expected for horses receiving long-term treatment.
Divers TJ, Byars TD, Shin SJ.Renal failure associated with infection of Leptospira interrogans was detected in a horse. Fever, leukocytosis, pyuria, isosthenuria, and azotemia were suggestive of an inflammatory urinary tract disease. Despite persistent pyuria, no bacteria were found during routine microscopic examinations or bacteriologic culturing of urine. A fluorescent antibody examination of the urine was positive for L interrogans. Serologic testing during a 6-month period, supported an acute infection with L interrogans serovar pomona. Treatment with intravenously administered fluids and antimicrobials resulted in c...
Kuskie KR, Smith JL, Wang N, Carter CN, Chaffin MK, Slovis NM, Stepusin RS, Cattoi AE, Takai S, Cohen ND.To determine whether airborne concentrations of virulent Rhodococcus equi at 2 horse breeding farms varied on the basis of location, time of day, and month. Methods: 2 farms in central Kentucky with recurrent R equi-induced pneumonia in foals. Methods: From February through July 2008, air samples were collected hourly for a 24-hour period each month from stalls and paddocks used to house mares and their foals. Concentrations of airborne virulent R equi were determined via a modified colony immunoblot technique. Differences were compared by use of zero-inflated negative binomial methods to dete...
More SJ, Aznar I, Myers T, Leadon DP, Clegg A.The research discusses an outbreak of Equine Infectious Anemia (EIA) in Ireland in 2006, with a particular focus on its modes of transmission, evident in clusters of cases found in […]
Sandstedt K, Engvall A.Sera from 116 and 89 Swedish pigs and horses respectively were examined for the presence of antibodies to L. bratislava. Antibodies were found in 18.1 and 49.4% respectively of pigs and horses examined. Presence of serum antibodies was not associated with clinical signs of infection.