Pathogens are microorganisms, such as bacteria, viruses, fungi, and parasites, that can cause disease in horses. These microorganisms interact with the equine immune system, often leading to a range of health issues that can affect individual horses or entire populations. Pathogens can be transmitted through various routes, including direct contact, vectors, or environmental exposure. Common equine pathogens include Streptococcus equi, Equine Herpesvirus, and Strongylus vulgaris. Understanding the interactions between equine hosts and pathogens is essential for disease prevention, management, and treatment. This page compiles peer-reviewed research studies and scholarly articles that explore the identification, transmission, and impact of pathogens on equine health.
Wang X, Ji Y, Su J, Xue Y, Xi H, Wang Z, Bi L, Zhao R, Zhang H, Yang L, Guo Z, Guan Y, Feng X, Sun C, Lei L, Ur Rahman S, Dong J, Han W, Gu J. subsp. serovar Abortusequi is a frequently reported pathogen causing abortion in mares. In this study, the preventive and therapeutic effects of phage P SAE-01E2 against Abortusequi in a mouse model of abortion were investigated. Phage P SAE-01E2 was stable at different temperatures (4 to 70°C) and pH values (pH 4 to 10) and could lyse the majority of the serogroup O:4 and O:9 strains tested (25/28). There was no lysogeny-related, toxin, or antibiotic resistance-related gene in the genome of P SAE-01E2. All of these characteristics indicate that P SAE-01E2 has the potential for use in pha...
Simonato G, Danesi P, Frangipane di Regalbono A, Dotto G, Tessarin C, Pietrobelli M, Pasotto D.Animal-assisted interventions (AAIs) are based on the establishment of a therapeutic relationship between animals and beneficiaries that is certain to provide positive effects, while currently, it reads as if AAIs aim at exposing stakeholders to potential risk of infection. The surveillance of zoonotic pathogens is necessary for guaranteeing common health. This study investigated the presence of potentially zoonotic parasites, including dermatophytes, in animals involved in AAIs. Between 2015 and 2017, 190 animals (equids, dogs, cats, birds, rabbits, rodents, and goats) were investigated. Anam...
Riley CB, Aldrich ED, Pemberton SL, Mirza AA. A 9-year-old warmblood gelding with a history of chronic intermittent tachypnoea and dyspnoea was presented for evaluation and removal of a mass on the left side of the neck. A fibrous mass adherent to the left jugular vein developed and was removed surgically 6 weeks later, at which time the owner requested an evaluation of the cause of the persistent respiratory signs first noted on primary admission. Clinical findings included coarse lung sounds on thoracic auscultation, tracheal wheeze, and an abnormal trans-tracheal aspirate. These findings, in addition to the results of ultrasonographi...
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.
Fuehrer HP, Alho AM, Kayikci FN, Shahi Barogh B, Rosa H, Tomás J, Rocha H, Harl J, Madeira de Carvalho L.Vector-borne diseases of zoonotic and/or veterinary relevance have been increasingly reported in horses globally, although data regarding working and military horses is lacking. Portuguese military horses may constitute a risk group for these pathogens, as they frequently work outdoors in various regions of the country. This study included 101 apparently healthy horses belonging to the Portuguese National Republican Guard. Blood samples were analyzed to determine the presence and prevalence of piroplasms, Anaplasmataceae, Rickettsia spp., and filarioid helminths. Overall 32.7% of the horses ga...
Cohen ND, Cywes-Bentley C, Kahn SM, Bordin AI, Bray JM, Wehmeyer SG, Pier GB.Strangles is a common disease of horses with worldwide distribution caused by the bacterium Streptococcus equi subspecies equi (SEE). Although vaccines against strangles are available commercially, these products have limitations in safety and efficacy. The microbial surface antigen β 1→6 poly-N-acetylglucosamine (PNAG) is expressed by SEE. Here we show that intramuscular (IM) injection alone or a combination of IM plus intranasal (IN) immunization generated antibodies to PNAG that functioned to deposit complement and mediate opsonophagocytic killing of SEE ex vivo. However, immunization st...
Ekruth J, Gottschalk C, Ulrich S, Gareis M, Schwaiger K.Stachybotrys (S.) chartarum is a cellulolytic mould with the ability to produce highly cytotoxic macrocyclic trichothecenes. Two chemotypes are defined according to their ability to produce either atranones or satratoxins. S. chartarum has been well known as the causative agent of the lethal disease stachybotryotoxicosis in horses. Further investigations revealed that this disease is strictly correlated with the presence of macrocyclic trichothecenes. Furthermore, their occurrence in water-damaged buildings has been linked to adverse health effects such as the sick building syndrome. As the ch...
Munday JS, Hardcastle MR, Sim M.A 10-year-old horse presented with two 3-cm diameter exophytic masses over the fetlock. Histology was consistent with a hyperplastic squamous papilloma and numerous cell changes consistent with papillomavirus (PV) infection were visible. Partial sequences of PV L1 and E1 ORFs were amplified using consensus PCR primers. The sequences were most similar to Equus caballus type 1 (EcPV1). However, as the sequences were only around 73% similar to EcPV1, they appear to be from a novel PV type that is likely to be within the genus. The papillomas were treated with topical imiquimod and resolved withi...
Goodrich EL, McLean A, Guarino C.Recent removal and relocation of feral donkeys from vast public lands to more concentrated holding pens, training facilities, and offsite adoption locations raises several health and welfare concerns. Very little is known regarding the common equid pathogens that are circulating within the feral donkey population in and around Death Valley National Park, California, USA. The aim of this study was to utilize serologic assays to assess previous exposure of these donkeys to equine herpesvirus 1 (EHV-1), equine influenza (EIV), West Nile virus (WNV), and (the causative agent of Lyme disease). The...
Al-Kass Z, Eriksson E, Bagge E, Wallgren M, Morrell JM.Stallion semen is known to contain environmental bacteria and normal commensals, and in some cases may contain opportunistic pathogens. These bacteria may negatively influence sperm quality during storage before artificial insemination. The bacteria isolated depend on the culture conditions and method of identification; therefore, the aim of this study was to identify as many of the bacteria present in stallion semen as possible by culturing aliquots of semen under a variety of conditions. Eleven semen samples were available: five extended semen samples from one stud together with a sample of ...
Klumplerova M, Splichalova P, Oppelt J, Futas J, Kohutova A, Musilova P, Kubickova S, Vodicka R, Orlando L, Horin P.The mammalian Major Histocompatibility Complex (MHC) is a genetic region containing highly polymorphic genes with immunological functions. MHC class I and class II genes encode antigen-presenting molecules expressed on the cell surface. The MHC class II sub-region contains genes expressed in antigen presenting cells. The antigen binding site is encoded by the second exon of genes encoding antigen presenting molecules. The exon 2 sequences of these MHC genes have evolved under the selective pressure of pathogens. Interspecific differences can be observed in the class II sub-region. The family E...
Uchida-Fujii E, Niwa H, Kinoshita Y, Nukada T.Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is used for bacterial identification by analyzing the spectra of isolates and comparing them against a database of reference spectra; it is known for its rapidity and accuracy. Although MALDI-TOF MS is used for identification of bacterial isolates from animals, not all animal pathogens are identified correctly. In this study, we used a commercial MALDI-TOF MS identification system to examine 3724 bacterial isolates from horses and their environments. Isolates that could not be identified with MALDI-TOF ...
Petry S, Sévin C, Kozak S, Foucher N, Laugier C, Linster M, Breuil MF, Dupuis MC, Hans A, Duquesne F, Tapprest J.Study of the rifampicin resistance of Rhodococcus equi strains isolated from French horses over a 20-year period. Rifampicin susceptibility was tested by disk diffusion (DD) and broth macrodilution methods, and rpoB gene sequencing and MLST were performed on 40 R. equi strains, 50.0% of which were non-susceptible to rifampicin. Consistency of results was observed between rifampicin susceptibility testing and rpoB sequencing. Strains non-susceptible to rifampicin by DD had a substitution at one of the sites (Asp516, His526 and Ser531) frequently encountered and conferring rifampicin resistance....
Díaz-Sánchez AA, Chilton NB, Roblejo-Arias L, Fonseca-Rodríguez O, Marrero-Perera R, Diyes CP, Yunik MEM, Lobo-Rivero E, Corona-González B.Spotted fever group (SFG) rickettsiae are obligatory intracellular bacteria that cause disease in humans and other animals. Ixodid ticks are the principal vectors of SFG rickettsiae. The present study aimed to determine the prevalence and species identity of SFG rickettsiae in ticks and horses from urban and rural areas of western Cuba using PCR assays. Tick samples, collected from 79 horses, consisted of 14 Amblyomma mixtum adults, 111 Dermacentor nitens adults and 19 pools of D. nitens nymphs (2-5 individuals/pool). The PCR results revealed the presence of Rickettsia spp. in 64% of the A. mi...
Tapia D, Sanchez-Villamil JI, Torres AG.Burkholderia mallei (Bm) is a facultative intracellular pathogen and the etiological agent of glanders, a highly infectious zoonotic disease occurring in equines and humans. The intrinsic resistance to antibiotics, lack of specific therapy, high mortality, and history as a biothreat agent, prompt the need of a safe and effective vaccine. However, the limited knowledge of protective Bm-specific antigens has hampered the development of a vaccine. Further, the use of antigen-delivery systems that enhance antigen immunogenicity and elicit robust antigen-specific immune responses has been limited a...
Erdemsurakh O, Purevdorj B, Ochirbat K, Adilbish A, Vanaabaatar B, Aoshima K, Kobayashi A, Kimura T.Glanders is caused by the gram-negative bacterium Burkholderia mallei. In this study, we investigated the histopathology and immunohistochemical localization of B. mallei in natural cases of equine glanders. Four horses showing clinical signs of nasal discharge and multiple cutaneous nodules or papulae in the hindlimbs and abdomen were reported in Mongolia. They tested positive for B. mallei infection on complement fixation, Rose Bengal agglutination, and mallein tests. Gross and histological lesions observed in these cases were similar to those previously reported in equine glanders. Immunohi...
Pusterla N, Rice M, Henry T, Barnum S, James K.The main objective of the study was to determine the frequency of detection of selected infectious respiratory viruses and bacteria in healthy horses presented over a 12-month period for routine dental care at 2 veterinary hospitals. Nasal secretions were collected from 579 horses and tested for equine herpesviruses (EHV-1, EHV-2, EHV-4, EHV-5), equine influenza virus (EIV), equine rhinitis A and B viruses (ERAV, ERBV), Streptococcus equi subspecies equi (S equi), S equi subspecies zooepidemicus (S zooepidemicus), and methicillin-resistant Staphylococcus aureus (MRSA) using routine diagnostic ...
Greenwood S, Chow-Lockerbie B, Ramsauer S, Wachoski-Dark G, Knight C, Wobeser B. papillomavirus type 2 (EcPV-2) has been recognized as a potential cause of a subset of genital squamous cell carcinomas (SCCs) in horses. In the current study, we measured EcPV-2 seropositivity in 50 healthy horses from Western Canada, and these were compared to a herd of horses with known EcPV-2 exposure. Second, the presence of EcPV-2 DNA was measured using EcPV-2-specific PCR (polymerase chain reaction), performed on a variety of tissues collected at necropsy from 70 horses that lacked any history, gross, or histologic evidence of neoplasia or papillomavirus-associated disease. EcPV-2-spec...
Bianchi MV, Mello LS, Ribeiro PR, Wentz MF, Stolf AS, Lopes BC, de Andrade CP, Snel GGM, Sonne L, Driemeier D, Pavarini SP.We document the causes and pathological findings in 50 cases of equine pneumonia and pleuritis in Southern Brazil. Suppurative (17/50), pyogranulomatous (14/50), aspiration (5/50), mycotic (4/50), bronchointerstitial (3/50), embolic (3/50) and eosinophilic granulomatous pneumonia (1/50) and pleuritis (3/50) were the main conditions identified. Streptococcus spp. were identified in 11 cases of suppurative pneumonia. Suppurative pneumonia was further divided into acute (8/17), subacute (6/17) and chronic (3/17) based on the morphological pattern of lesions. Rhodococcus equi was identified in all...
Millar BC, Moore JE.Steam disinfection has become established as a trusted method of microbial decontamination; however, there have been no reports on the use of this technology to disinfect equipment used in collection of semen in artificial insemination practice. Hence, it was the aim of this study to examine the survival of Taylorella asinigenitalis, Pseudomonas aeruginosa, and Klebsiella pneumoniae venereal bacterial pathogens using domestic steam disinfection. Sixteen bacterial pathogens from three genera Taylorella, Pseudomonas, and Klebsiella each at an inoculum density of approximately 1.5 × 107 colony-...
Fagre AC, Mayo CE, Pabilonia KL, Landolt GA.Detection of is difficult as a result of intermittent leptospiruria and brief leptospiremia. Hence, diagnosis relies heavily on serologic testing, the reference method of which is the microscopic agglutination test (MAT). In horses, clinical leptospirosis has been associated with abortion, recurrent uveitis, and sporadic cases of hepatic and renal disease. Little information exists on the seroprevalence of antibodies to in equids in the United States; past nationwide studies suggest that the seroprevalence in some areas is as high as 77% (reciprocal titer ≥ 100). We tested sera from 124 ...
Steinman A, Navon-Venezia S.Antimicrobial resistance (AMR) is an increasingly recognized global public health threat to the modern health-care system that could hamper the control and treatment of infectious diseases [...].
Steinman A, Navon-Venezia S.Antimicrobial resistance (AMR) is an increasingly recognized global public health threat to the modern health-care system that could hamper the control and treatment of infectious diseases [...].
Krajaejun T, Kittichotirat W, Patumcharoenpol P, Rujirawat T, Lohnoo T, Yingyong W.Genome sequences are a vital resource for accelerating the biological exploration of an organism of interest. Pythium destruens (a synonym of Pythium insidiosum) causes a difficult-to-treat infectious disease called pythiosis worldwide. Detection and management of pythiosis are challenging. Basic knowledge of the disease is lacking. Genomes of this organism isolated from different continents (i.e., Asia and the Americas) have been sequenced and publicly available. Here, we sequenced the genome of an Australian isolate of P. destruens. Genome data will facilitate the comparative analysis of thi...
Yildirim A, Okur M, Uslug S, Onder Z, Yetismis G, Duzlu O, Ciloglu A, Simsek E, Inci A.Horses might play an important role as reservoir hosts in the epidemiology of Enterocytozoon bieneusi, which is one of the most important zoonotic microsporidian pathogens, with a wide range of hosts. Nevertheless, limited information is available on the infection rates and genotypes of E. bieneusi in horses, and no data are available on the occurrence and molecular characteristics of E. bieneusi in horses in Turkey. We determined the prevalence of E. bieneusi among horses raised on farms from two provinces of Central Anatolia Region, by amplification of the partial small subunit ribosomal RNA...
Zhao A, Zhang Y, Wang W, Jing B, Xing J, Tao D, Zhao W, Qi M.Enterocytozoon bieneusi, a zoonotic pathogen, has the potential to infect both immunocompromised and immunocompetent humans. It is found in large number of animals; however, not much is known regarding its prevalence in equine animals, particularly donkeys. This is the first molecular epidemiological evaluation of E. bieneusi in 178 free-ranging donkeys from five countrysides; and 502 farmed donkeys from 18 farms in 12 cities of Xinjiang, China by Nested PCR. Results: E. bieneusi was detected in 2.5% (17/680) donkeys, with 2.6% (13/502) in farmed and 2.2% (4/178) in free-ranging ones. Sequence...
Baumann S, Gurtner C, Marti H, Borel N.Species of genus are important pathogens of animals, with a worldwide distribution and broad host range. Some species, such as , also pose a zoonotic disease risk. Abortion is one of the many diseases that has been associated with chlamydial infections in animals, with most attention focused on the economic impacts to sheep production. The role of chlamydia in equine abortions is unknown. Using the family-specific 23S ribosomal RNA (rRNA) real-time PCR, we tested 169 formalin-fixed, paraffin-embedded fetal membrane samples from 162 equine abortion cases collected between 2000 and 2018 in Swi...
Norton E, McCue ME.A role for a genetic contribution to equine metabolic syndrome (EMS) and pars pituitary intermedia dysfunction (PPID) has been hypothesized. Heritability estimates of EMS biochemical measurements were consistent with moderately to highly heritable traits. Further, genome-wide association analyses have identified hundreds of regions of the genome contributing to EMS and candidate variants have been identified. The genetics of PPID has not yet been proven. Continued research for the specific genetic risk factors for both EMS and PPID is crucial for gaining a better understanding of the pathophys...
Uzcanga GL, Bubis J.Two horses were infected with distinct non-tsetse transmitted Venezuelan stocks, namely TeAp-N/D1 and TeAp-El Frio01 . Preceding reports have revealed that a 64-kDa antigenic glycopolypeptide (p64), which is the soluble form of the predominant variant surface glycoprotein from TeAp-N/D1 , can be used as a good antigen for immunodiagnosis of animal trypanosomosis. Here, the course of the experimental acute infection in both horses was monitored by evaluating total anti-p64 IgG and particular anti-p64 γ-specific IgG and μ-specific IgM isotypes in sera using indirect enzyme-linked immunoso...
Burkett-Cadena ND, Gibson J, Lauth M, Stenn T, Acevedo C, Xue RD, McNelly J, Northey E, Hassan HK, Fulcher A, Bingham AM, van Olphen J, van Olphen A....Zoonotic mosquito-borne viruses, such as the West Nile virus (WNV) and eastern equine encephalitis virus (EEEV), are major public health threats in the United States. Early detection of virus transmission and targeted vector management are critical to protect humans against these pathogens. Sentinel chickens and pool screening of mosquitoes, the most widely used methods of arbovirus early detection, have technical time-lags that compromise their early-detection value. The exploitation of sugar-feeding by trapped mosquitoes for arbovirus surveillance may represent a viable alternative to other ...
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...
Pearce JW, Giuliano EA, Moore CP.To evaluate and compare the in vitro susceptibility of Aspergillus and Fusarium spp. isolated from horses with ulcerative keratomycosis, address regional differences in equine keratomycosis isolates, and provide susceptibility data to update prior studies. Methods: Fourteen horses with ulcerative keratomycosis. Methods: Banked fungal isolates from equine corneal ulcers (eight Aspergillus spp. and six Fusarium spp.) were identified at The University of Texas Health Science Center at San Antonio. In vitro minimum inhibitory concentration and susceptibility to natamycin, fluconazole, itraconazole...
Hassan AA, Ulbegi-Mohyla H, Kanbar T, Alber J, Lämmler C, Abdulmawjood A, Zschöck M, Weiss R.The present study was designed to characterize phenotypically and genotypically seven Arcanobacterium haemolyticum strains obtained from infections of six horses. All seven strains showed the cultural and biochemical properties typical of A. haemolyticum and were susceptible to most of the antibiotics tested. The species identification could be confirmed by amplification and sequencing of the 16S rRNA gene and the 16S-23S rRNA intergenic spacer region and by PCR amplification of species-specific parts of the gene encoding phospholipase D in A. haemolyticum. Use of the latter could possibly imp...
Kennedy CA, Walsh C, Karczmarczyk M, O'Brien S, Akasheh N, Quirke M, Farrell-Ward S, Buckley T, Fogherty U, Kavanagh K, Parker CT, Sweeney T....Extraintestinal pathogenic E. coli (ExPEC) possess the ability to cause extraintestinal infections such as urinary tract infections, neonatal meningitis and sepsis. While information is readily available describing pathogenic E. coli populations in food-producing animals, studies in companion/sports animals such as horses are limited. In addition, many antimicrobial agents used in the treatment of equine infections are also utilised in human medicine, potentially contributing to the spread of antibiotic resistance determinants among pathogenic strains. The aim of this study was to phenotypical...
Ueno TE, Costa FB, Moraes-Filho J, Agostinho WC, Fernandes WR, Labruna MB.Rickettsia rickettsii is vectored by ticks, and some vertebrate hosts can be sources of infection to ticks during bacteremic periods. In Brazil, the main vector for R. rickettsii is the tick Amblyomma sculptum, a member of the A. cajennense complex. Horses, in turn, are one of the major hosts for A. sculptum. In this study, horses experimentally infected with R. rickettsii were assessed for clinical changes and their capability to transmit the infection to A. sculptum ticks. Four horses were infected with R. rickettsii through either intraperitoneal injection or infestation with R. rickettsii-...
Anzai T, Timoney JF, Kuwamoto Y, Fujita Y, Wada R, Inoue T.The glossy non-encapsulated strain of Steptococcus equi, NCTC 9682, was compared with the matt strain Hidaka/95/2 which expresses a medium sized capsule and with the mucoid CF32 which expresses a large sized capsule in phagocytosis assays and for virulence in inoculated horses. The three strains, NCTC 9682, Hidaka /95/2 and CF32 produced 2.0, 3.1, and 5.3 mg/g wet cells respectively after 3 h incubation, but similar amounts of M-like proteins, cytotoxin and mitogen. NCTC 9682 showed no resistance to phagocytosis by equine neutrophils regardless of the presence of opsonin while strains Hidaka /...
Bruhn O, Paul S, Tetens J, Thaller G.Defensins represent an important class of antimicrobial peptides. These effector molecules of the innate immune system act as endogenous antibiotics to protect the organism against infections with pathogenic microorganisms. Mammalian defensins are classified into three distinct sub-families (alpha-, beta- and theta-defensins) according to their specific intramolecular disulfide-bond pattern. The peptides exhibit an antimicrobial activity against a broad spectrum of microorganisms including bacteria and fungi. Alpha-Defensins are primarily synthesised in neutrophils and intestinal Paneth cells....
López C, Carmona JU, Giraldo CE, Alvarez ME.1) To evaluate the bacteriostatic in vitro effect of pure platelet-rich plasma (P-PRP), pure platelet-rich gel (P-PRG), leukocyte-poor gel (LPG), platelet-poor plasma (PPP), and heat inactivated plasma (IP) against methicillin-sensitive Staphylococcus aureus (MSSA) over a period of 24 hours. 2) To determine the degradation of platelet factor-4 (PF-4), transforming growth factor beta 1 (TGF-β1), and platelet-derived growth factor isoform BB (PDGF-BB) in these equine blood components. 3) To establish correlations between platelet and leukocyte counts, PF-4 concentrations, and MSSA growth. Metho...
Pusterla N, Leutenegger CM, Chae JS, Lutz H, Kimsey RB, Dumler JS, Madigan JE.This paper describes the kinetics of the human granulocytic ehrlichiosis agent in the blood of horses experimentally infected by intravenous inoculation with infected leukocytes and by infected ticks as evaluated by using a real-time quantitative PCR assay. The data obtained indicated differences in the period of incubation, duration of rickettsemia, and initial and maximal ehrlichial loads between the two routes of infection.
Jelocnik M, Jenkins C, O'Rourke B, Barnwell J, Polkinghorne A.Chlamydia psittaci is an important avian pathogen with spillover from infected wild and domesticated birds also posing a risk to human health. We recently reported a case of C. psittaci equine placentitis associated with further spillover to humans. Molecular typing of this case revealed it belonged to the 6BC clade of C. psittaci, a globally distributed highly virulent set of strains, typically linked to infection spillover from parrots. Equine chlamydiosis associated with C. psittaci infection has previously been reported elsewhere in countries where parrots are not endemic, however, rais...
Acke E, Midwinter AC, Lawrence K, Gordon SJ, Moore S, Rasiah I, Steward K, French N, Waller A.To estimate the prevalence of β-haemolytic Lancefield group C streptococci in healthy dogs, cats and horses; to determine if frequent contact with horses was associated with isolation of these species from dogs and cats; and to characterise recovered S. equi subsp. zooepidemicus isolates by multilocus sequence typing. Methods: Oropharyngeal swabs were collected from 197 dogs and 72 cats, and nasopharyngeal swabs from 93 horses. Sampling was carried out at the Massey University Veterinary Teaching Hospital, on sheep and beef farms or on premises where horses were present. All animals were heal...
Tranquille CA, Parkin TD, Murray RC.Lateral condylar (LC) fractures of the third metacarpus (McIII) are a common reason for euthanasia in racehorses, and may be the result of repetitive overloading or cumulative pathological change. Magnetic resonance imaging (MRI) allows monitoring of bone and cartilage to detect pathological and adaptive changes that may be precursors of fracture. Objective: To describe bone and cartilage MRI features in the distal condyles of McIII of Thoroughbred racehorses, with and without condylar fracture. Objective: 1) A greater degree of bone and cartilage adaptation or pathology will be seen in fractu...
Álvarez-Narváez S, Giguère S, Berghaus LJ, Dailey C, Vázquez-Boland JA.Conjugation is one of the main mechanisms involved in the spread and maintenance of antibiotic resistance in bacterial populations. We recently showed that the emerging macrolide resistance in the soilborne equine and zoonotic pathogen is conferred by the (46) gene carried on the 87-kb conjugative plasmid pRErm46. Here, we investigated the conjugal transferability of pRErm46 to 14 representative bacteria likely encountered by in the environmental habitat. mating experiments demonstrated conjugation to different members of the genus as well as to and spp. at frequencies ranging from ∼10...
Tyrrell JD, Qurollo BA, Tornquist SJ, Schlaich KG, Kelsey J, Chandrashekar R, Breitschwerdt EB.Certain vector-borne organisms serve as etiological agents of equine disease. After previously identifying a new Ehrlichia species in horses from Mérida, we aimed to determine the infection frequency and screen for a wide range of vector-borne organisms from 93 tick-exposed, Ehrlichia seropositive horses in this region. PCR assays were performed to identify infection by organisms within the following genera: Anaplasma, Babesia, Bartonella, Ehrlichia, Leishmania, Mycoplasma, Neorickettsia, Rickettsia and Theileria. Overall, 90/93 horses (96.8%) were infected with one or more vector-borne organ...
Lupala CS, Kumar V, Su XD, Wu C, Liu H.The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the COVID-19 pandemic. Angiotensin-converting enzyme 2 (ACE2) has been identified as the host cell receptor that binds to the receptor-binding domain (RBD) of the SARS-COV-2 spike protein and mediates cell entry. Because the ACE2 proteins are widely available in mammals, it is important to investigate the interactions between the RBD and the ACE2 of other mammals. Here we analyzed the sequences of ACE2 proteins from 16 mammals, predicted the structures of ACE2-RBD complexes by homology modeling, and refi...
Bonhomme D, Werts C.Leptospirosis is a zoonotic infectious disease affecting all vertebrates. It is caused by species of the genus Leptospira, among which are the highly pathogenic L. interrogans. Different mammals can be either resistant or susceptible to the disease which can present a large variety of symptoms. Humans are mostly asymptomatic after infection but can have in some cases symptoms varying from a flu-like syndrome to more severe forms such as Weil's disease, potentially leading to multiorgan failure and death. Similarly, cattle, pigs, and horses can suffer from acute forms of the disease, including ...
Barros AT, Foil LD.Two studies evaluated the potential use of spatial barriers to reduce the mechanical transmission of disease agents by tabanids in the Pantanal region of Brazil. Tabanids at stations separated by four different distances (5, 10, 25, and 50m) were marked. In the first study, tabanids were marked and allowed to feed until engorgement or natural interruption occurred and captured if they transferred to the other horse. A total of 2847 tabanids belonging to nine different species were marked. The percentage of tabanids that moved between horses was 10.5 at 5m, 6.8 at 10m, and 4.6 at 25m. In the se...
Oikawa M, Kamada M, Yoshikawa Y, Yoshikawa T.Seven horses that died of pneumonia associated with transport yielded Streptococcus equi subsp. zooepidemicus (S.z.) from their pulmonary lesions. These lesions were divisible roughly into two types, serous haemorrhagic pneumonia and multiple foci of coagulative necrosis, which were considered to reflect a temporal difference in the process of lesion formation. Immunohistologically, S.z. antigen was detected in both types of lesion. Acute necrotic lacunar tonsillitis was considered to play an important role in the onset of the pneumonia.
Waller AS, Robinson C.The host-restricted bacterium Streptococcus equi is the causative agent of equine strangles, the most frequently diagnosed infectious disease of horses worldwide. The disease is characterized by abscessation of the lymph nodes of the head and neck, leading to significant welfare and economic cost. S. equi is believed to have evolved from an ancestral strain of Streptococcus zooepidemicus, an opportunistic pathogen of horses and other animals. Comparison of the genome of S. equi strain 4047 with those of S. zooepidemicus identified examples of gene loss due to mutation and deletion, and gene ga...
Sheoran AS, Sponseller BT, Holmes MA, Timoney JF.Equine strangles, caused by the clonal pathogen Streptococcus equi, is a source of serious economic loss despite the widespread use of commercial vaccines. The anti-phagocytic 58 kDa M-like protein (SeM) is an important protective antigen. The objective of this study was to define differences, if any, between SeM-specific convalescent serum and mucosal IgA and IgG subisotypes and those induced by vaccination with commercial strangles vaccine. SeM-specific opsonophagocytic IgGb was the predominant serum antibody in horses intramuscularly vaccinated or recently recovered from infection. Infectio...
Uprety T, Sreenivasan CC, Hause BM, Li G, Odemuyiwa SO, Locke S, Morgan J, Zeng L, Gilsenan WF, Slovis N, Metcalfe L, Carter CN, Timoney P, Horohov D....Equine rotavirus group A (ERVA) is one of the most common causes of foal diarrhea. Starting in February 2021, there was an increase in the frequency of severe watery to hemorrhagic diarrhea cases in neonatal foals in Central Kentucky. Diagnostic investigation of fecal samples failed to detect evidence of diarrhea-causing pathogens including ERVA. Based on Illumina-based metagenomic sequencing, we identified a novel equine rotavirus group B (ERVB) in fecal specimens from the affected foals in the absence of any other known enteric pathogens. Interestingly, the protein sequence of all 11 segment...
Raspa F, Chessa S, Bergero D, Sacchi P, Ferrocino I, Cocolin L, Corvaglia MR, Moretti R, Cavallini D, Valle E.Diet is one of the main factors influencing the intestinal microbiota in horses, yet a systematic characterization of the microbiota along the length of the digestive tract in clinically healthy horses, homogenous for age and breed and receiving a specific diet is lacking. Unassigned: The study used 16S rRNA amplicon sequencing to characterize the microbiota of the intestinal tracts of 19 healthy Bardigiano horses of 14.3 ± 0.7 months of age fed one of two diets. Nine horses received a high-starch diet (HS), and ten horses received a high-fiber diet (HF). After 129 days, the horse...
Cirak VY, Hermosilla C, Bauer C.Quantitative faecal and post-mortem examinations of 16 ponies, 1 to 2 1/2 years of age, originating from 3 farms in northern Germany were performed in February 1995 to determine the prevalence and intensity of gastrointestinal parasites in these animals. A total of 33 species of metazoan parasites was recovered: three tapeworm species (Anoplocephala perfoliata, A. magna, Paranoplocephala mamillana), Strongylus vulgaris, S. edentatus, small strongyles (including four Triodontophorus spp., Craterostomum acuticaudatum and 19 cyathostome species), Oxyuris equi, Parascaris equorum, Habronema majus ...
Ribeiro MG, Seki I, Yasuoka K, Kakuda T, Sasaki Y, Tsubaki S, Takai S.We investigated the prevalence of virulent Rhodococcus equi in clinical isolates from 41 foals (19 sporadic and seven endemic cases) in Brazil between 1991 and 2003. Of the 41 virulent isolates, six contained an 85-kb type I plasmid, 33 contained an 87-kb type I plasmid, both of which have been found in isolates from the Americas, and the remaining two contained a new variant, which did not display the EcoRI, EcoT22I and BamHI digestion patterns of the 11 representative plasmids already reported (85-kb types I-IV; 87-kb types I and II; 90-kb types I-V). We tentatively designated the new varian...
McBrearty KA, Murray A, Dunowska M.To determine which viruses circulate among selected populations of New Zealand horses and whether or not viral infections were associated with development of respiratory disease. Methods: Nasal swabs were collected from 33 healthy horses and 52 horses with respiratory disease and tested by virus isolation and/or PCR for the presence of equine herpesviruses (EHV) and equine rhinitis viruses. Results: Herpesviruses were the only viruses detected in nasal swab samples. When both the results of nasal swab PCR and virus isolation were considered together, a total of 41/52 (79%) horses with respirat...
Cohen ND, Smith KE, Ficht TA, Takai S, Libal MC, West BR, DelRosario LS, Becu T, Leadon DP, Buckley T, Chaffin MK, Martens RJ.To compare isolates of Rhodococcus equi on the basis of geographic source and virulence status by use of pulsed-field gel electrophoresis (PFGE). Methods: 290 isolates of R equi (218 virulent isolates from foals and 72 avirulent isolates from feces, soil, and respiratory tract samples) obtained between 1985 and 2000 from horses and horse farms from 4 countries. Methods: DNA from isolates was digested with the restriction enzyme Asel and tested by use of PFGE. Products were analyzed for similarities in banding patterns by use of dendrograms. A similarity matrix was constructed for isolates, and...
van Duijkeren E, Wannet WJ, Heck ME, van Pelt W, Sloet van Oldruitenborgh-Oosterbaan MM, Smit JA, Houwers DJ.We studied 232 Salmonella strains from horses with salmonellosis in The Netherlands, isolated in the period from 1993 to 2000 in order to provide insight in the dynamics of sero-, phage types (pt) and antibiotic susceptibilities over time. The strains were tested for susceptibility to seven antimicrobial agents using the agar diffusion method. In addition, the isolates were sero typed and Salmonella enterica subspecies enterica Typhimurium and Enteritidis strains were further phage typed. S. Typhimurium strains of phage type 506 and 401 (both classified as DT 104 in the English phage typing sy...
Womble A, Giguère S, Lee EA.The objective of this study was to determine the disposition of orally administered doxycycline in foals. Six healthy 4- to 8-week-old foals were used. Doxycycline was administered to each foal via the intragastric (IG) route at dosages of 10 and 20 mg/kg, in a cross-over design. After the first 10 mg/kg dose, five additional doses were administered at 12-h intervals. A microbiological assay was used to measure doxycycline activity in serum, urine, peritoneal fluid, synovial fluid, cerebrospinal (CSF), pulmonary epithelial lining fluid (PELF), and bronchoalveolar (BAL) cells. Following adminis...
