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.
Gilliam LL, Ownby CL, McFarlane D, Canida A, Holbrook TC, Payton ME, Krehbiel CR.Rattlesnake bites in horses are not uncommon and the clinical outcomes are widely variable. Treatment of horses with anti-venom is often cost prohibitive and could have negative consequences; therefore, the development of a quantitative test to determine if anti-venom therapy is indicated would be valuable. The objective of this study was to develop an ELISA to detect rattlesnake venom in biological samples from clinically bitten horses. Nineteen horses were enrolled in the study. Urine was available from 19 horses and bite site samples were available from 9 horses. A double sandwich fluoresce...
Vázquez-Boland JA, Giguère S, Hapeshi A, MacArthur I, Anastasi E, Valero-Rello A.Rhodococcus equi is a soil-dwelling pathogenic actinomycete that causes pulmonary and extrapulmonary pyogranulomatous infections in a variety of animal species and people. Young foals are particularly susceptible and develop a life-threatening pneumonic disease that is endemic at many horse-breeding farms worldwide. R. equi is a facultative intracellular parasite of macrophages that replicates within a modified phagocytic vacuole. Its pathogenicity depends on a virulence plasmid that promotes intracellular survival by preventing phagosome-lysosome fusion. Species-specific tropism of R. equi fo...
Vannucci FA, Kelley MR, Gebhart CJ.Lawsonia intracellularis is an obligate intracellular bacterium and the causative agent of proliferative enteropathy (PE). The disease is endemic in pigs, emerging in horses and has also been reported in a variety of other animal species, including nonhuman primates. Comparing the whole genome sequences of a homologous porcine L. intracellularis isolate cultivated for 10 and 60 passages in vitro, we identified a 18-kb prophage-associated genomic island in the passage 10 (pathogenic variant) that was lost in the passage 60 (non-pathogenic variant). This chromosomal island comprises 15 genes dow...
Bastos RG, Suarez CE, Laughery JM, Johnson WC, Ueti MW, Knowles DP.Members of the CCp protein family have been previously described to be expressed on gametocytes of apicomplexan Plasmodium parasites. Knocking out Plasmodium CCp genes blocks the development of the parasite in the mosquito vector, making the CCp proteins potential targets for the development of a transmission-blocking vaccine. Apicomplexans Babesia bovis and Babesia bigemina are the causative agents of bovine babesiosis, and apicomplexan Theileria equi causes equine piroplasmosis. Bovine babesiosis and equine piroplasmosis are the most economically important parasite diseases that affect world...
Daly JM, Elton D.The calculation of p(epitope) values, a sequence-based measure of antigenic distance between strains, was developed for human influenza. The potential to apply the p(epitope) value to equine influenza vaccine strain selection was assessed. There was a negative correlation between p(epitope) value and vaccine efficacy for pairs of vaccine and challenge strains used in cross-protection studies in ponies that just reached statistical significance (p=0.046) only if one pair of viruses was excluded from the analysis. Thus the p(epitope) value has potential to provide additional data to consider in ...
Schlusselhuber M, Torelli R, Martini C, Leippe M, Cattoir V, Leclercq R, Laugier C, Grötzinger J, Sanguinetti M, Cauchard J.Rhodococcus equi, the causal agent of rhodococcosis, is a major pathogen of foals and is also responsible for severe infections in immunocompromised humans. Of great concern, strains resistant to currently used antibiotics have emerged. As the number of drugs that are efficient in vivo is limited because of the intracellular localization of the bacterium inside macrophages, new active but cell-permeant drugs will be needed in the near future. In the present study, we evaluated, by in vitro and ex vivo experiments, the ability of the alpha-helical equine antimicrobial peptide eCATH1 to kill int...
Barbic L, Vilibic-Cavlek T, Listes E, Stevanovic V, Gjenero-Margan I, Ljubin-Sternak S, Pem-Novosel I, Listes I, Mlinaric-Galinovic G, Di Gennaro A....We report the first serological evidence of Usutu virus (USUV) infection in horses in Croatia. During 2011, 1380 horse serum samples from healthy animals were collected from six northern Croatian counties. All samples were first screened for West Nile virus (WNV) immunoglobulin G (IgG) antibodies using an enzyme-linked immunosorbent assay (ELISA). Sixty-nine WNV ELISA-reactive samples were further tested for WNV antibodies by a virus neutralization assay (VN assay) and plaque reduction neutralization test (PRNT), and USUV by a VN assay and tick-borne encephalitis virus (TBEV) antibodies by PRN...
North SE, Wakeley PR, Mayo N, Mayers J, Sawyer J.Infection with Streptococcus equi subspecies equi (S. equi) is endemic in the UK. A proportion of horses serve as long-term carriers and act as a reservoir of infection. Detection of these persistently infected horses is difficult using standard culture techniques owing to a lack of sensitivity and overgrowth by contaminating bacteria. In addition, differentiation of this causative bacterium from the closely related S. equi zooepidemicus has made the development of reliable and accurate diagnostic tests difficult. Objective: To develop and validate a sensitive and specific real-time PCR assay ...
Wylie CE, Shaw DJ, Fordyce FM, Lilly A, McGorum BC.Equine grass sickness (EGS) remains a frequently fatal disease of equids in Britain. Since previous investigations of signalment- and meteorology-related risk factors for EGS have yielded some conflicting data, further investigation is warranted. Objective: To identify signalment- and meteorology-related risk factors for EGS in Scotland. Methods: Retrospective time-matched case-control study. Methods: This study was undertaken using data for 455 EGS cases and 910 time-matched controls that were referred to the Royal (Dick) School of Veterinary Studies, and average UK Meteorological Office weat...
Fielding CL, Meier CA, Magdesian KG, Pusterla N.Fecal shedding of Salmonella spp. was recently documented in 8% of endurance horses presented to equine referral centers for colic. Previous studies have documented fecal shedding of Salmonella spp. in as few as 0.8% of the general horse population, although horses with colic appear to be at higher risk. Fecal Salmonella spp. shedding before and after endurance horse competitions has not been evaluated. Fecal samples were collected from 204 horses during three separate 100 mile endurance competitions. Following incubation in selenite broth, 289 fecal samples were tested by real-time PCR analys...
Na W, Kang B, Kim HI, Hong M, Park SJ, Jeoung HY, An DJ, Moon H, Kim JK, Song D.Equine influenza virus (EIV) causes a highly contagious respiratory disease in equids, with confirmed outbreaks in Europe, America, North Africa, and Asia. Although China, Mongolia, and Japan have reported equine influenza outbreaks, Korea has not. Since 2011, we have conducted a routine surveillance programme to detect EIV at domestic stud farms, and isolated H3N8 EIV from horses showing respiratory disease symptoms. Here, we characterized the genetic and biological properties of this novel Korean H3N8 EIV isolate. This H3N8 EIV isolate belongs to the Florida sublineage clade 1 of the America...
Schuster RK, Sivakumar S.Equine habronematidosis has a global distribution and is caused by three spirurid species, Habronema muscae, Habronema microstoma and Draschia megastoma. A case of cutaneous habronematidosis in a stallion in a stable in Dubai, UAE gave occasion to investigate the parasite situation on the farm. Patent H. muscae infections were diagnosed in 18 out of 49 horses in a stable in Dubai, UAE with a xenodiagnostic test using houseflies as indicator host. All horses in the stable were treated with a single dose of moxidectin administered orally as 2% gel in a dosage of 0.4 mg/kg body weight and the eff...
Spelta CW, Axon JE, Begg A, Diallo IS, Carrick JB, Russell CM, Collins NM.Equine multinodular pulmonary fibrosis (EMPF) is a recently described form of interstitial pneumonia associated with the presence of equine herpesvirus type 5 (EHV-5). Since 2007, several case reports from America, Europe and the United Kingdom have further characterised the clinical presentation and laboratory findings of this disease. Methods: Three Thoroughbred broodmares were diagnosed with EMPF. Diagnosis was based on lung histopathology and positive identification of EHV-5 using PCR DNA amplification. There was multiple organ involvement in all three cases, including identification of EH...
Pelkonen S, Lindahl SB, Suomala P, Karhukorpi J, Vuorinen S, Koivula I, Väisänen T, Pentikäinen J, Autio T, Tuuminen T.Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) is a zoonotic pathogen for persons in contact with horses. In horses, S. zooepidemicus is an opportunistic pathogen, but human infections associated with S. zooepidemicus are often severe. Within 6 months in 2011, 3 unrelated cases of severe, disseminated S. zooepidemicus infection occurred in men working with horses in eastern Finland. To clarify the pathogen's epidemiology, we describe the clinical features of the infection in 3 patients and compare the S. zooepidemicus isolates from the human cases with S. zooepidemicus isolates...
Soares IR, Silva SO, Moreira FM, Prado LG, Fantini P, Maranhão Rde P, da Silva Filho JM, Melo MN, Palhares MS.This study reports the first evidence of infection by Leishmania infantum in Equus caballus in Americas and the first mixed infection of L. infantum/Leishmania braziliensis on this mammalian species in the world. The diagnoses was based on presence of parasites in lesions and bone marrow aspirates, their identification by using specific primers for L. infantum and L. braziliensis complexes and also serological methods IFAT and ELISA. The analysis of the PCR products suggested mixed infection in three animals. Further studies involving equine leishmaniasis are carrying out in order to clarify t...
Pires MS, Santos TM, Santos HA, Vilela JA, Peixoto MP, Roier EC, Silva CB, Barreira JD, Lemos ER, Massard CL.The objective of this study was to evaluate factors associated with infestation by Amblyomma cajennense on horses in two microregions of the state of Rio de Janeiro. Horses on 62 farms in the municipalities of the Itaguaí and Serrana microregions were evaluated between January and May 2009. The animals were examined to determine the presence of ticks and infestation level. The animals' rearing and management were assessed on each farm property using an epidemiological questionnaire. Out of the 635 horses evaluated, 41.6% were infested with A. cajennense. It was observed that farms in low-alti...
Dzięgiel B, Adaszek L, Winiarczyk M, García-Bocanegra I, Carbonero A, Dębiak P, Winiarczyk S.The aim of this study was to conduct a comparative analysis of the 16S rRNA gene fragment nucleotide sequences for Anaplasma phagocytophilum strains detected in the blood of horses from various parts of Europe. The study comprised 234 horses that had had contact with ticks. Using PCR, the genetic material of A. phagocytophilum was identified in the blood of 42 animals. The sequences of the 16S RNA gene amplicons that were obtained from our A. phagocytophilum isolates had 100 % similarity with each other and 96.4-100 % similarity with Anaplasma spp. sequences selected from those available i...
Hartley CA, Dynon KJ, Mekuria ZH, El-Hage CM, Holloway SA, Gilkerson JR.The evolutionary success of the equine gammaherpesviruses (GHVs) is demonstrated by their consistent and widespread presence in horse populations worldwide. Equine GHVs establish infection in young foals and can be continually detected over the lifetime of the host either by recrudescence of latent infections or by re-infection. A definitive diagnosis of clinical disease in horses due to GHV infection remains challenging given the ubiquitous nature of the GHVs in horses without clinical signs, as well as in horses with clinical signs ranging from mild respiratory disease to severe equine multi...
Lopes AP, Sousa S, Dubey JP, Ribeiro AJ, Silvestre R, Cotovio M, Schallig HD, Cardoso L, Cordeiro-da-Silva A.Leishmania infantum and Toxoplasma gondii are protozoa with zoonotic and economic importance. Prevalences of antibodies to these agents were assessed in 173 horses from the north of Portugal. Results: Antibodies to L. infantum were detected by the direct agglutination test (DAT); seven (4.0%) horses were seropositive with DAT titres of 200 (n = 5), 800 (n = 1) and ≥ 1600 (n = 1). Antibodies to T. gondii were assayed by the modified agglutination test (MAT); 23 (13.3%) horses were seropositive with MAT titres of 20 (n = 13), 40 (n = 5), 80 (n = 3) and ≥ 160 (...
Detournay O, Morrison DA, Wagner B, Zarnegar B, Wattrang E.This study aimed at identifying all of the type I interferon (IFN) genes of the horse and at monitoring their expression in equine cells on in vitro induction. We identified 32 putative type I IFN loci on horse chromosome 23 and an unplaced genomic scaffold. A phylogentic analysis characterized these into 8 different type I IFN classes, that is, putative functional genes for 6 IFN-α, 4 IFN-β, 8 IFN-ω (plus 4 pseudogenes), 3 IFN-δ (plus 1 pseudogene), 1 IFN-κ and 1 IFN-ε, plus 1 IFN-ν pseudogene, and 3 loci belonging to what has previously been called IFN-αω. Our analyses indicate that...
Gorino AC, Oliveira-Filho JP, Taniwaki SA, Basso RM, Zakia LS, Araujo JP, Borges AS.Aural plaques occur on the skin of the medial surface of the pinnae of horses. In this study the presence of Equus caballus papillomavirus (EcPV)-3 and -4 DNA was assessed in 45 such plaques using a 'touchdown' PCR. Papillomaviruses (PVs) were detected in 62.3% (28/45) of samples: EcPV-3 and -4 DNA in 8.89% (4/45) and 37.78% (17/45) of samples, respectively, with 15.56% (7/45) of samples exhibiting co-infection. Viral DNA was not detected in 37.78% (17/45) of samples, suggesting the possible existence of other equine PVs. Neither EcPV-3 nor -4 were detected in negative control skin. This study...
Bordin AI, Suchodolski JS, Markel ME, Weaver KB, Steiner JM, Dowd SE, Pillai S, Cohen ND.Rhodococcus equi is an important pathogen of foals. Enteral administration of live, virulent R. equi during early life has been documented to protect against subsequent intrabronchial challenge with R. equi, indicating that enteral mucosal immunization may be protective. Evidence exists that mucosal immune responses develop against both live and inactivated micro-organisms. The extent to which live or inactivated R. equi might alter the intestinal microbiome of foals is unknown. This is an important question because the intestinal microbiome of neonates of other species is known to change over...
Craigo JK, Ezzelarab C, Cook SJ, Chong L, Horohov D, Issel CJ, Montelaro RC.Lentiviral envelope (Env) antigenic variation and associated immune evasion present major obstacles to vaccine development. The concept that Env is a critical determinant for vaccine efficacy is well accepted, however defined correlates of protection associated with Env variation have yet to be determined. We reported an attenuated equine infectious anemia virus (EIAV) vaccine study that directly examined the effect of lentiviral Env sequence variation on vaccine efficacy. The study identified a significant, inverse, linear correlation between vaccine efficacy and increasing divergence of the ...
Horsington J, Lynch SE, Gilkerson JR, Studdert MJ, Hartley CA.Of the many members that comprise the family Picornaviridae, only two species are known to infect horses: equine rhinitis A virus (ERAV) and equine rhinitis B virus (ERBV). Each species now occupies a distinct phylogenetic branch within the family, with the single serotype of ERAV grouping with the aphthoviruses, such as foot-and-mouth disease virus (FMDV), and the three serotypes of ERBV as the sole members of the genus Erbovirus. The high seroprevalence of equine picornaviruses in horse populations worldwide contrasts with the relatively few reports of detection of these viruses and poor und...
Miao Q, Wang X, She LN, Fan YT, Yuan FZ, Yang JF, Zhu XQ, Zou FC.Toxoplasma gondii is an intracellular protozoan parasite that infects almost all warm-blooded animals, including humans, with a worldwide distribution. There have been limited reports about the seroprevalence of T. gondii infection in equids around the world and little is known about the seroprevalence of T. gondii in equids in southwestern China, in particular in Yunnan Province. The objective of the present investigation was to estimate the seroprevalence of T. gondii infection in equids in this area. Methods: A total of 399 serum samples (266 from horses and 133 from donkeys) were collected...
Wendell LC, Potter NS, Roth JL, Salloway SP, Thompson BB.Eastern Equine Encephalitis (EEE) virus is an arbovirus that mostly causes asymptomatic infection in humans; however, some people can develop a neuroinvasive infection associated with a high mortality. Methods: We present a case of a patient with severe neuroinvasive EEE. Results: A 21-year-old man initially presented with headache, fever, and vomiting and was found to have a neutrophilic pleocytosis in his cerebrospinal fluid. He eventually was diagnosed with EEE, treated with high-dose methylprednisolone and intravenous immunoglobulin. His course in the NeuroIntensive Care Unit was complicat...
Velineni S, Timoney JF.Streptococcus zooepidemicus of Lancefield group C is a highly variable tonsillar and mucosal commensal that usually is associated with opportunistic infections of the respiratory tract of vertebrate hosts. More-virulent clones have caused epizootics of severe respiratory disease in dogs and horses. The virulence factors of these strains are poorly understood. The antiphagocytic protein SeM is a major virulence factor and protective antigen of Streptococcus equi, a clonal biovar of an ancestral S. zooepidemicus strain. Although the genome of S. zooepidemicus strain H70, an equine isolate, conta...
Mendez D, Buttner P, Speare R.Following the emergence of Hendra virus (HeV), private veterinarians have had to adopt additional infection control strategies to manage this zoonosis. Between 1994 and 2010, seven people became infected with HeV, four fatally. All infected people were at a higher risk of exposure from contact with horses as they were either veterinary personnel, assisting veterinarians, or working in the horse industry. The management of emerging zoonoses is best approached from a One Health perspective as it benefits biosecurity as well as a public health, including the health of those most at risk, in this ...
Barbey C, Budin-Verneuil A, Cauchard S, Hartke A, Laugier C, Pichereau V, Petry S.Rhodococcus equi is one of the most important causes of mortality in foals between 1 and 6 months of age. Although rare, infection also occurs in a variety of other mammals including humans, often following immunosuppression of various causes. Secreted proteins are known to mediate important pathogen-host interactions and consequently are favored candidates for vaccine development as they are the most easily accessible microbial antigens to the immune system. Here, we describe the results of a proteomic analysis based on SDS-PAGE, immunoblot and mass spectrometry, which was carried out aiming ...
Bermúdez C S, Zaldívar Y, Domínguez A L, Hernández M, de Antinori MEB, Krawczak FS.Rickettsia amblyommatis is widely distributed in the Americas, and has been reported to infect different species of ticks within its distribution. In Panama, R. amblyommatis is the most common Rickettsia and its presence was molecularly detected in nine species of ticks and one flea species. This work described the isolation of R. amblyommatis in Vero cells by shell vial technique, from Amblyomma mixtum ticks collected from a captive tapir from Gamboa (Colon province), and a horse from El Valle de Antón (Cocle province). These represent the first isolations of R. amblyommatis in Panama.
A cross-sectional study was conducted to assess the circulation and risk factors associated with West Nile virus (WNV) exposure in equine and wild bird populations following the largest epidemic outbreak ever reported in Spain. A total of 305 equids and 171 wild birds were sampled between November 2020 and June 2021. IgG antibodies against flaviviruses were detected by blocking enzyme-linked immunosorbent assay (bELISA) in 44.9% (109/243) and 87.1% (54/62) of unvaccinated and vaccinated equids, respectively. The individual seroprevalence in unvaccinated individuals (calculated on animals serop...
Lee SH, Lee SE, Seo MG, Goo YK, Cho KH, Cho GJ, Kwon OD, Kwak D, Lee WJ.The present study investigated the seroprevalence of Toxoplasma gondii (T. gondii) antibodies by ELISA in horses reared in Korea. Serum samples were collected from 2009 through 2013 from 816 horses reared in Korea. Analysis was performed using a commercial toxoplasmosis ELISA kit to detect anti-T. gondii antibodies. Overall, 24 out of 816 horses (2.9%) were seropositive for T. gondii. The result was analyzed by age, gender, breed and region. Significant differences were observed according to breed and region (P<0.05). This is the first nationwide serological investigation of T. gondii in ho...
Skotarczak B, Wodecka B, Rymaszewska A, Adamska M.Ixodes ricinus has the potential to transmit zoonotic pathogens to humans and domestic animals. The feeding I. ricinus (n = 1737) collected from 49 Shetland ponies and questing ones from vegetation (n = 371) were tested for the presence and differentiation of the bacterial species. DNA of I. ricinus ticks was examined with PCR and sequencing analysis to identify species of Borrelia burgdorferi sensu lato (Bbsl), Anaplasma phagocytophilum and Rickettsia spp. Altogether, 24.3 % I. ricinus of the infested horses and 12.4 % ticks from vegetation carried at least one pathogen species. Horse-f...
Odelros E, Kendall A, Hedberg-Alm Y, Pringle J.Peritonitis in horses is historically associated with prolonged treatment regimens of broad-spectrum antimicrobials and a guarded prognosis for survival. The condition is most often seen as a secondary complication to traumatic injuries involving the abdominal cavity, rupture of bowel or abdominal surgery. However, cases of idiopathic peritonitis with no such underlying cause have been described. In Sweden idiopathic peritonitis is commonly identified and, in contrast to peritonitis secondary to traumatic incidents, affected horses appear to respond well to medical treatment. The objectives of...
Aquino LP, Machado RZ, Lemos KR, Marques LC, Garcia MV, Borges GP.The present research investigated the presence of T. evansi antibodies in animals from the subregion of Nhecolandia, in the Pantanal Sul-mato-grossense, by means of an enzyme linked immunosorbent assay (ELISA) and indirect immunofluorescence antibody test (IFAT), and the pattern of polypeptide recognition by sera from experimentally and naturally infected hosts using Western blotting. Serum samples were obtained from bovines (n = 102), horses (n = 98), and dogs (n = 55), and from 32 free-ranging coatis (Nasua nasua). None of the bovines were found positive, while sera from 16 dogs (29%) and 23...
Boyle AG, Sweeney CR, Kristula M, Boston R, Smith G.To identify factors associated with an increased likelihood that horses would have a serum Streptococcus equi SeM-specific antibody titer > or = 1:1,600. Methods: Cross-sectional study. Methods: 188 healthy client-owned horses. Methods: A single serum sample from each horse was tested for SeM-specific antibody titer with an ELISA. Multivariate logistic regression was used to identify factors associated with having a titer > or = 1:1,600. Results: Age, breed, and vaccination status were significantly associated with the likelihood of having a titer > or = 1:1,600. The odds of having a ...
Hurtgen JP.The breeding soundness evaluation of a stallion is a thorough investigation of a stallion's libido, mating ability, and semen quality. The evaluation should include historical data about the medical aspects of the horse's performance and breeding career, observations and breeding behavior characteristics, collection and evaluation of semen, tests to determine freedom from infectious or contagious disease, and production of foals free of genetic defects. This information should allow the examiner to anticipate the impact of the stallion on the reproductive efficiency of a group of mares. The br...
Blanco-Lobo P, Rodriguez L, Reedy S, Oladunni FS, Nogales A, Murcia PR, Chambers TM, Martinez-Sobrido L.Vaccination remains the most effective approach for preventing and controlling equine influenza virus (EIV) in horses. However, the ongoing evolution of EIV has increased the genetic and antigenic differences between currently available vaccines and circulating strains, resulting in suboptimal vaccine efficacy. As recommended by the World Organization for Animal Health (OIE), the inclusion of representative strains from clade 1 and clade 2 Florida sublineages of EIV in vaccines may maximize the protection against presently circulating viral strains. In this study, we used reverse genetics tech...
Stewart AJ, Cuming RS.Fungal respiratory disease is a rare occurrence in horses. Fungal organisms are ubiquitous in the equine environment; however, there is a geographic predisposition for disease development, with fungal respiratory infections seen more commonly by practitioners working in tropical or subtropical environments. Diagnosis and treatment of fungal respiratory infections pose a challenge for the equine practitioner, and the prognosis for complete resolution of infection is often guarded; however, new antifungal medications are likely to improve treatment success. This article summarizes the available ...
Sundstrom KD, Lineberry MW, Grant AN, Duncan KT, Ientile MM, Little SE.Ticks are common on horses, but recent publications characterizing equine tick infestations in North America are lacking. Methods: To further understand attachment site preferences of common ticks of horses, and to document the seasonality of equine tick infestation in northeastern Oklahoma, horses from eight farms were evaluated twice a month over a 1-year period. Each horse was systematically inspected beginning at the head and moving caudally to the tail. Attachment sites of ticks were recorded and all ticks collected were identified to species and stage. Results: Horses (26 males and 62 fe...
Zimmermann W, Dürrwald R, Ludwig H.Borna disease virus in naturally infected horses, a donkey and sheep was detected for the first time by amplification of viral RNA using PCR. In contrast to a control group of healthy horses, brain tissue was positive by this assay in all animals with neurological symptoms. The use of a second round of PCR with nested primers following Southern hybridization confirmed the specificity and increased the sensitivity of the test. Comparison with conventional methods recommends this technique for monitoring of BDV infections at a molecular level.
Museux K, Arcari G, Rodrigo G, Hennart M, Badell E, Toubiana J, Brisse S.Corynebacteria of the diphtheriae species complex (CdSC) can cause diphtheria in humans and have been reported from companion animals. We aimed to describe animal infection cases caused by CdSC isolates. A total of 18,308 animals (dogs, cats, horses, and small mammals) with rhinitis, dermatitis, nonhealing wounds, and otitis were sampled in metropolitan France (August 2019 to August 2021). Data on symptoms, age, breed, and the administrative region of origin were collected. Cultured bacteria were analyzed for tox gene presence, production of the diphtheria toxin, and antimicrobial susceptibili...
Gomes FA, Jansen AM, Machado RZ, Jesus Pena HF, Fumagalli MJ, Silva A, Alves BF, Roque ALR, Moraes Figueiredo LT.Arboviruses and protozoans can cause neurologic disorders in horses. In Brazilian Amazon, several horses presenting signs compatible with disorders caused by these infectious agents have been observed. To contribute to the knowledge of this epidemiological picture, we sought to construct a serological diagnostic panel for neurotrophic infectious agents in local horses. A total of 213 blood samples from horses were collected from 29 farms in three municipalities. Samples were evaluated and considered positive when they met the following criteria: titers ≥ 1:80 with the indirect fluorescent an...
Hoffman AM, Staempfli HR, Prescott JF, Viel L.A double-blind randomized clinical trial was undertaken to determine the value of parenterally administered Streptococcus equi M-protein vaccine in foals during an epizootic of strangles. Weaned mixed-breed foals (n = 664) housed on 2 adjacent feed-lots (A and B) arrived over a 5-day period, 2 weeks before primary vaccination. Foals in lot B (n = 114) were randomly administered vaccine (n = 59) or saline solution (placebo; n = 55) on 3 occasions at biweekly intervals. Foals in lot A (n = 450) were given 1 dose of vaccine (n = 225) or placebo. The following clinical observations were scored bli...
Peterson AE, Davis MF, Awantang G, Limbago B, Fosheim GE, Silbergeld EK.Animals on farms may be a potential reservoir and environmental source of methicillin-resistant Staphylococcus aureus (MRSA). Expanded surveillance methods for animal-associated MRSA are needed. To develop an environmental sampling method and to determine the correlation between animal and environmental MRSA positivity in the farm setting, we sampled horses, cattle, and their local environments at several farms in the mid-Atlantic United States. We obtained nasal swabs from 13 racehorses at first visit, and 11 racehorses at the same farm eight weeks later. We also sampled 26 pleasure horses an...
Giguère S, Berghaus LJ, Lee EA.Studies with facultative intracellular bacterial pathogens have shown that evaluation of the bactericidal activity of antimicrobial agents against intracellular bacteria is more closely associated with in vivo efficacy than traditional in vitro susceptibility testing. The objective of this study was to determine the relative activity of 10 antimicrobial agents against intracellular Rhodococcus equi. Equine monocyte-derived macrophages were infected with virulent R. equi and exposed to erythromycin, clarithromycin, azithromycin, rifampin, ceftiofur, gentamicin, enrofloxacin, vancomycin, imipene...
Tsachev I, Baymakova M, Pantchev N.Lyme borreliosis, granulocytic anaplasmosis and monocytic ehrlichiosis are well studied in humans and dogs. In horses, these diseases are not widely investigated and limited information is available about their occurrence. The purpose of this study was to present the first ELISA-based report on the seroprevalence of Anaplasma phagocytophilum, Ehrlichia spp. and Borrelia burgdorferi in horses from Northern Bulgaria. A total of 192 horses were investigated from three regions in Northern Bulgaria (Northwestern, North-Central and Northeastern Bulgaria). All equine sera were tested for A. phagocyto...
Gauci PJ, Wu JQ, Rayner GA, Barabé ND, Nagata LP, Proll DF.DNA vaccines encoding different portions of the structural proteins of western equine encephalitis virus were tested for the efficacy of their protection in a 100% lethal mouse model of the virus. The 6K-E1 structural protein encoded by the DNA vaccine conferred complete protection against challenge with the homologous strain and limited protection against challenge with a heterologous strain.
Daly JM, Whitwell KE, Miller J, Dowd G, Cardwell JM, Smith KC.Equine influenza is usually a transient and self-limiting disease. However, during an outbreak of equine influenza in the UK in 2003 there were reports of unusually severe clinical signs among unvaccinated animals. Two influenza-infected horses developed neurological signs, and one was subjected to euthanasia. Post-mortem examination of the brain revealed viral-type non-suppurative encephalitis, and influenza virus antigen was demonstrated by immunolabelling of sections of nasal mucosa. A syndrome known as influenza-associated encephalopathy has been described in man. Although not proved, the ...
COllinson PN, O'Rielly JL, Ficorilli N, Studdert MJ.Ocular problems characterized by conjunctivitis, epiphora, and keratopathy were detected in 35 of 80 Thoroughbred weanling foals that also had respiratory disease. Ocular problems were determined to be caused by infection with equine herpesvirus type 2 (EHV-2) and were successfully treated with ophthalmic medication containing idoxuridine. Equine herpesvirus type 2 isolated from 3 of 5 foals from which samples were collected. The identity of the causative virus as EHV-2 was confirmed by use of electron microscopy, restriction endonuclease DNA fingerprinting, and Southern blot analysis.
García JA, Navarro MA, Fresneda K, Uzal FA.Tyzzer disease (TD) is caused by Clostridium piliforme, a gram-negative and obligate intracellular bacterium. The disease occurs in multiple species. A triad of lesions, namely colitis, hepatitis, and myocarditis, is described in cases of TD in some species, such as rats and mice. We carried out a retrospective analysis of 25 equine cases with a diagnosis of TD; 24 of 25 cases occurred in foals <45 d old; the remaining foal was 90 d old. There were 12 males and 12 females; no sex information was available for one foal. The affected breeds were Quarter Horse, Thoroughbred, Arabian, Paint, and...
