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.
Jacobi S, Townsend WM, Bolin CA.To evaluate whether equine serum administered via a simulated subpalpebral lavage system (SPL) supports proliferation of Streptococcus zooepidemicus or Pseudomonas aeruginosa within the tubing. Methods: A sterile i.v. catheter with injection cap was inserted into sterilized silicone tubing (Mila). To mimic an SPL within the dorsal conjunctival fornix, the tubing was secured to an elevated platform. The tip of the tubing extended from the platform into a vial containing culture medium just inoculated with approximately 1.5 x 10(8) CFU/mL P. aeruginosa or S. zooepidemicus. To mimic administratio...
Corrente M, D'Abramo M, Latronico F, Greco MF, Bellacicco AL, Greco G, Martella V, Buonavoglia D.A methicillin-resistant (MR) Staphylococcus epidermidis strain was isolated from a saddle horse affected by osteolysis. MR coagulase-negative staphylococci (MRCNS) were isolated from 11 of 14 (78.8%) horses housed in the same riding club. By typing of the SCCmec region, almost the strains displayed a non typeable (NT) pattern and possessed the ccr type 2. Altogether, the high prevalence of MRCNS and the detection of NT SCCmec types support the hypothesis that horses may represent a reservoir of MRCNS for humans and that equine MRCNS may act as potential source of resistance genes for other sta...
Woldehiwet Z.Anaplasma phagocytophilum is the recently designated name replacing three species of granulocytic bacteria, Ehrlichia phagocytophila, Ehrlichia equi and the agent of human granulocytic ehrlichiosis, after the recent reorganization of the families Rickettsiaceae and Anaplasmataceae in the order Rickettsiales. Tick-borne fever (TBF), which is caused by the prototype of A. phagocytophilum, was first described in 1932 in Scotland. A similar disease caused by a related granulocytic agent was first described in horses in the USA in 1969; this was followed by the description of two distinct granulocy...
Guss B, Flock M, Frykberg L, Waller AS, Robinson C, Smith KC, Flock JI.Streptococcus equi subspecies equi (S. equi) is a clonal, equine host-adapted pathogen of global importance that causes a suppurative lymphodendopathy of the head and neck, more commonly known as Strangles. The disease is highly prevalent, can be severe and is highly contagious. Antibiotic treatment is usually ineffective. Live attenuated vaccine strains of S. equi have shown adverse reactions and they suffer from a short duration of immunity. Thus, a safe and effective vaccine against S. equi is highly desirable. The bacterium shows only limited genetic diversity and an effective vaccine coul...
Pusterla N, Byrne BA, Hodzic E, Mapes S, Jang SS, Magdesian KG.A quantitative real-time (RT)-PCR assay was developed to detect Salmonella spp. in the feces of 911 equine species admitted to a veterinary hospital. Fresh feces and feces enriched for 24h in selenite broth were assessed by conventional culture and by RT-PCR targeting the Salmonella invA gene. The detection limit for the RT-PCR assay was 3 and 10 organisms, respectively, when spiked samples were purified from selenite broth and feces. The analytical specificity was 100% based on the detection of a panel of 40 salmonella serotypes from five serogroups and the lack of cross-reactivity with non-r...
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...
Hébert L, Cauchard J, Doligez P, Quitard L, Laugier C, Petry S.There is great concern about the potential pathogen contamination of horse manure compost spread in the same fields horses graze in. To ensure that pathogen destruction occurs, temperatures need to be sufficiently high during composting. Here, we investigated the survival rate of two marker organisms, Rhodococcus equi and Parascaris equorum eggs, exposed to temperatures potentially encountered during horse manure composting. Our results show that the time required to achieve a 1 log10 reduction in R. equi population (D-value) are 17.1 h (+/-1.47) at 45 degrees C, 8.6 h (+/-0.28) at 50 degrees ...
Singh BR.Vancomycin resistant and multi-drug-resistant enterococci are the major emerging pathogens in surgical, neonatal, and tertiary care units. Methods: In this study, 267 enterococci from different clinical and non-clinical samples of equine origin were tested for their antimicrobial drug sensitivity against 19 antimicrobials using disc diffusion method. Results: A total of 80.2% enterococci tested were resistant to vancomycin and 99.6% to multiple-drugs. There was a significant association between haemolytic potential and vancomycin resistance (chi(2), 0.00). Enterococci isolates from healthy equ...
Smith KL, Allen GP, Branscum AJ, Frank Cook R, Vickers ML, Timoney PJ, Balasuriya UB.A panel of 426 archived EHV-1 isolates collected (1951-2006) from equine abortions was analyzed using a real-time Taq-Man((R)) allelic discrimination PCR assay. Based on previous findings, isolates possessing adenine at nucleotide position 2254 (A(2254)) in ORF30 were classified as having a non-neuropathogenic genotype and those with guanine at 2254 (G(2254)) were designated as the neuropathogenic genotype. The resultant data demonstrated that viruses with the neuropathogenic genotype existed in the 1950s and isolates with this genotype increased from 3.3% in the 1960s to 14.4% in the 1990s. T...
Langley R, Morris T.Millions of individuals are in contact with horses through occupational or recreational activities. Injuries from horses are responsible for over 100,000 emergency room visits each year in the United States. Although various types of traumatic injuries related to direct contact with horses are well described, roughly 3% to 4.5% of all reported injuries are due to bites by equines. The immediate injuries are commonly either blunt or penetrating trauma to local tissue; however, the bite exposure may also transmit a microbial agent of equine origin that can lead to a zoonotic infection. In almost...
Franzén P, Aspan A, Egenvall A, Gunnarsson A, Karlstam E, Pringle J.Anaplasma phagocytophilum infects several mammalian species, and can persist in sheep, dogs, and calves. However, whether this organism persists in horses or induces long-term clinical abnormalities is not known. Objective: To evaluate whether A. phagocytophilum can persist in horses and to document clinical findings for 3 months after complete recovery from acute disease. Methods: Five clinically normal adult horses that had recovered spontaneously from experimentally induced acute disease caused by a Swedish equine isolate of A. phagocytophilum. Methods: Horses were monitored for up to 129 d...
Bermúdez SE, Eremeeva ME, Karpathy SE, Samudio F, Zambrano ML, Zaldivar Y, Motta JA, Dasch GA.Several outbreaks of Rocky Mountain spotted fever have occurred in recent years in Colombian communities close to the border with Panama. However, little is known about rickettsiae and rickettsial diseases in eastern Panamanian provinces, the Darien Province and the Kuna Yala, located north of the endemic area in Colombia. In 2007, 289 ticks were collected in several towns from dogs, horses, mules, cows, and pigs. DNA was extracted from 124 Dermacentor nitens, 64 Rhipicephalus sanguineus, 43 Amblyomma ovale, 35 A. cajennense, 10 Boophilus microplus, 4 A. oblongoguttatum, and 9 A. cajennense ny...
Reinemeyer CR, Nielsen MK.Equids are hosts to dozens of species of internal parasites that infect no other domestic animals. Virtually all horses, especially those exposed to pasture, experience some level of parasitism continuously. Despite pathologic evidence of parasitic damage in various organs and tissues, few parasitisms are manifested systemically in well-managed horses. Contrary to conventional wisdom, only three common parasitisms of horses are likely to be manifested as colic: Strongylus vulgaris, Parascaris equorum, and Anoplocephala perfoliata. This article discusses the life cycles, pathophysiology, manife...
Albini S, Abril C, Franchini M, Hüssy D, Filioussis G.Stenotrophomonas maltophilia (S. maltophilia) is a nonfermentative bacterium, which is naturally resistant against a panel of commonly-used antibiotics. It is frequently isolated from humans with chronic respiratory disease, e.g. cystic fibrosis or chronic obstructive pulmonary disease. In veterinary medicine S. maltophilia is perceived to be a mere coloniser. We herewith report 7 strains of S. maltophilia isolated from animals, of which 5 strains were harvested from 3 horses, a dog and a cat with chronic respiratory disease. The dog isolate showed resistance to trimethoprim / sulphamethoxazol...
Turner CE, Kurupati P, Wiles S, Edwards RJ, Sriskandan S.Currently there is no licensed vaccine against the human pathogen Streptococcus pyogenes. The highly conserved IL-8 cleaving S. pyogenes cell envelope proteinase SpyCEP is surface expressed and is a potential vaccine candidate. A recombinant N-terminal part of SpyCEP (CEP) was expressed and purified. AntiCEP antibodies were found to neutralize the IL-8 cleaving activity of SpyCEP. CEP-immunized mice had reduced bacterial dissemination from focal S. pyogenes intramuscular infection and intranasal infection. We also identified a functional SpyCEP-homolog protease SeCEP, expressed by the equine p...
Valerio L, Marini F, Bongiorno G, Facchinelli L, Pombi M, Caputo B, Maroli M, Della Torre A.Knowledge of the frequency of contact between a mosquito species and its different hosts is essential to understand the role of each vector species in the transmission of diseases to humans and/or animals. However, no data are so far available on the feeding habits of Aedes albopictus in Italy or in other recently colonized temperate regions of Europe, due to difficulties in collecting blood-fed females of this diurnal and exophilic species. We analyzed Ae. albopictus host-feeding patterns in two urban and two rural sites within the area of Rome (Italy). Ae. albopictus was collected using stic...
Causey RC, Artiushin SC, Crowley IF, Weber JA, Homola AD, Kelley A, Stephenson LA, Opitz HM, Guilmain S, Timoney JF.Attenuated Salmonella enterica serovar Typhimurium MGN707, expressing the SzP protective protein of the MB9 serovar of Streptococcus equi subspecies zooepidemicus (SzP-MB9) was tested for its safety and efficacy as a nebulised intranasal vaccine against streptococcal uterine infections in mares. In a preliminary study, vaccinated mares (n=5) displayed serum, nasal and uterine responses (P<0.05) to S. Typhimurium lipopolysaccharide (St-LPS). Subsequently, vaccinated mares (expressor group, n=7), but not mares vaccinated with the vector only (control group, n=7), displayed significant increas...
Meehan M, Lewis MJ, Byrne C, O'Hare D, Woof JM, Owen P.Fibrinogen-binding protein (FgBP, also termed SeM) is a cell-wall-associated anti-phagocytic M-like protein of the equine pathogen Streptococcus equi subsp. equi, and binds fibrinogen (Fg) and IgG. FgBP binds Fg avidly through residues located at the extreme N terminus of the molecule, whereas the IgG-binding site is more centrally located between the A and B repeats. FgBP binds equine IgG4 and IgG7 subclasses through interaction with the CH2-CH3 interdomain region of IgG-Fc, and possesses overlapping Fc-binding sites with protein A and protein G. In this study, FgBP truncates containing defin...
von Bargen K, Haas A.The soil actinomycete Rhodococcus equi is a pulmonary pathogen of young horses and AIDS patients. As a facultative intracellular bacterium, R. equi survives and multiplies in macrophages and establishes its specific niche inside the host cell. Recent research into chromosomal virulence factors and into the role of virulence plasmids in infection and host tropism has presented novel aspects of R. equi infection biology and pathogenicity. This review will focus on new findings in R. equi biology, the trafficking of R. equi-containing vacuoles inside host cells, factors involved in virulence and ...
Svraka S, van der Veer B, Duizer E, Dekkers J, Koopmans M, Vennema H.Acute gastroenteritis is one of the most common diseases worldwide, with viruses, particularly noroviruses, being the leading cause in developed countries. In The Netherlands, systematic surveillance of gastroenteritis outbreaks of suspected viral etiology was established by the National Institute for Public Health and the Environment in 1994. Since 2002, the total number of outbreaks reported has been increasing, and with that comes the need for sensitive assays that can be performed quickly. In addition, the diagnostic demand changed so that now the proportion of samples from hospitals is hi...
Zeman P, Jahn P.Anaplasma phagocytophilum is a tick-borne rickettsial pathogen that has measurable genetic heterogeneity across its geographical range and reservoir spectrum. In the present study, publicly available sequences of the genes that have prevailingly been used for typing A. phagocytophilum were analysed to identify the segments giving the highest resolution with respect to the predictability of host and geographical provenances of the strains. Selected partial sequences of 16S rRNA, groL, msp4 and ank genes were then employed in a tentative multilocus typing scheme used to characterize the strains ...
Monego F, Maboni F, Krewer C, Vargas A, Costa M, Loreto E.This study evaluated the molecular characteristics of Rhodococcus equi isolates obtained from horses by a multiplex PCR assay that amplifies the vap gene family (vapA, -B, -C, -D, -E, -F, -G, and -H). A total of 180 R. equi isolates were studied from four different sources, namely healthy horse feces (112), soil (12), stalls (23), and clinical isolates (33) from horse-breeding farms. The technique was performed and confirmed by sequencing of amplified vap gene family controls. Thirty-two (17.8%) of the R. equi isolates were positive for the vapA gene and carried at least three other vap genes....
Barquero N, Chanter N, Laxton R, Wood JL, Newton JR.The objective of this study was to characterise the molecular epidemiology of Streptococcus zooepidemicus isolated from the respiratory tracts of 198 Thoroughbred racehorses based at three Newmarket training yards over a 10 month period. Typing utilised two separate PCR procedures targeting the M-like protein hypervariable and the 16S-23S RNA gene intergenic spacer regions of the bacterium. S. zooepidemicus, isolated from 23% (224/983) of study samples, comprised 24 different types of varying prevalence. The four most common types, A1HV4, A1HV2, C1HVu and D1HV1, accounted for 45% of all the ty...
Bruhn O, Cauchard J, Schlusselhuber M, Gelhaus C, Podschun R, Thaller G, Laugier C, Leippe M, Grötzinger J.Defensins are small effector molecules of the innate immune system, synthesised by various organisms including plants and animals. The peptides act as endogenous antibiotics with an antimicrobial activity against a broad spectrum of microbes including bacteria, fungi and viruses. alpha-Defensins are a subgroup of the defensin family, their synthesis is limited to some tissues and furthermore to some mammalian species including the horse. Equine DEFA1 is an enteric alpha-defensin exclusively produced in Paneth cells. The peptide showed an activity against a broad spectrum of microbes, but typic...
Muscatello G, Gilkerson JR, Browning GF.Virulent Rhodococcus equi causes pyogranulomatous bronchopneumonia in foals. The route of infection of foals has been considered to be inhalation of aerosolized bacteria from soil that is contaminated with equine feces. Thus, disease caused by R. equi has been regarded as an opportunistic infection of environmental origin and not a contagious disease. In this study, we report the exhalation of virulent R. equi from the respiratory tract of naturally infected foals. A handheld air-monitoring system was used to recover virulent R. equi from the exhaled breath of foals, and the concentration of v...
Hoopes JT, Stark CJ, Kim HA, Sussman DJ, Donovan DM, Nelson DC.Streptococcus equi is the causative agent of the purulent infection equine strangles. This disease is transmitted through shedding of live bacteria from nasal secretions and abscess drainage or by contact with surfaces contaminated by the bacteria. Disinfectants are effective against S. equi, but inactivation by environmental factors, damage to equipment, and toxicity are of great concern. Bacteriophage-encoded lysins (cell wall hydrolases) have been investigated as therapeutic agents due to their ability to lyse susceptible gram-positive organisms. Here, we investigate the use of one lysin, P...
Bade D, Portis E, Keane C, Hallberg J, Bryson L, Sweeney M, Boner P.In vitro activity of ceftiofur and six other antimicrobial agents was evaluated against 79 Streptococcus equi subsp zooepidemicus isolates collected from horses with respiratory disease in Europe during 2007 and 2008. In addition, the in vitro activity of ceftiofur and other antimicrobial drugs was assessed against 59 S. equi subsp zooepidemicus and 49 S. equi subsp equi isolates collected by veterinary diagnostic laboratories in Europe from 2002 to 2006. The lowest concentration of ceftiofur that inhibited the growth of 90% of the isolates (MIC90) was 0.12 microg/ml, with the Clinical Laborat...
Rodríguez-Bertos A, Corchero J, Castaño M, Peña L, Luzón M, Gómez-Bautista M, Meana A.The pathological alterations caused by Anoplocephala perfoliata in the ileocaecal junction of 28 equids slaughtered in an abattoir in Madrid (Central Spain) are described. The lesions were scored in grades based on the intensity of the damage and were related to the tapeworm number observed. The first grade (grade I) of alterations consisted of a slight enteritis associated with focal erosions observed in 43% of parasitized animals with low parasitic burden (1-26 tapeworms). The second grade (grade II) was a focal pseudomembranous enteritis, present in the ileocaecal junctions of 36% infected ...
Goodrich LR.Much has been learned in the past decade about osteomyelitis. The inhibitory mechanisms of the "biofilm slime" layer that is formed by bacterial extracapsular exopolysaccharides and binds to bone, joints, and implants are now better understood than in the past. The surface colonization of bacteria that occurs within these biofilms is a biologic phenomenon that is somewhat unique to orthopedic infections. This survival strategy of bacteria is effective, and it is important for veterinarians who treat osteomyelitis to be aware of current diagnostic and therapeutic treatment modalities. The pract...
Lyskova P, Hubka V, Petricakova A, Dobias R, Cmokova A, Kolarik M.Trichophyton bullosum is a zoophilic dermatophyte from the Arthroderma benhamiae complex with a poorly known distribution. In this study, we report a case of dermatophytosis caused by T. bullosum in a 6-year-old male horse who had a skin lesion located in a saddle area. The infection spread rapidly to the upper chest and to both sides of the trunk. The dermatophyte was isolated in culture and identified by sequence analysis of the internal transcribed spacer regions (ITS rDNA). To date, this is the first verified case of animal infection due to T. bullosum in Europe following the 2012 report o...
Ellenberger MA, Kaeberle ML, Roth JA.A lymphocyte blastogenic assay was developed to serve as an in vitro correlate of cell-mediated immunity to Rhodococcus (Corynebacterium) equi (R equi) in the equine species. Lymphocytes obtained from a group of experimental ponies showed no response in cell culture to R equi heat extract or lysozyme extract antigens. Ponies were assigned to groups for experimental inoculation. Three ponies were inoculated subcutaneously with live R equi, 3 were given live R equi by intranasal and intratracheal routes, and 4 ponies were left untreated. Lymphocytes from all inoculated ponies had a mitogenic res...
Rotchanapreeda T, Sae-Chew P, Lohnoo T, Yingyong W, Rujirawat T, Kumsang Y, Payattikul P, Jaturapaktrarak C, Intaramat A, Pathomsakulwong W....Pythiosis, a life-threatening disease caused by , has been increasingly diagnosed worldwide. A recently developed immunochromatographic test (ICT) enables the rapid diagnosis of pythiosis. During the 3-year clinical implementation of ICT in Thailand, we collected the laboratory reports of 38 animals with suspected pythiosis and detected ICT false-positive results in three horses and a dog with basidiobolomycosis. and cause infections with indistinguishable clinical and microscopic features. This study investigated cross-reactive antibodies by probing and crude extracts and cell-free synthe...
Lees VW, Gale SP.Sera from horses in Alberta, submitted to Agriculture and Agri-Food Canada for routine testing for equine infectious anemia from January 1987 to June 1989, were tested for antibody against 13 serovars of pathogenic Leptospira spp., using the microscopic agglutination test. The purpose of the study was to investigate the prevalence of serum titers to those serovars in horses in Alberta, and to analyze the associated risk factors. Descriptive statistics were compiled and logistic regressions were computed. Titers to L. interrogans serovars icterohaemorrhagiae, bratislava, copenhageni, and autumn...
Blunden AS, Mackintosh ME.A series of 31 thoroughbreds and 18 non-thoroughbreds was examined post mortem to assess what bacteria might be present in the lower respiratory tract, and to assess their significance by correlating the bacteriological findings with histological changes in the lung. The distal trachea and seven representative lung sites were swabbed in each case. Sixty-six per cent of the sites were sterile with remaining sites producing scanty growths of mainly coagulase negative Staphylococcus spp., E. coli, Bacillus spp. and Pseudomonas spp. Anaerobes, mainly Clostridium perfringens, Bacteroides fragilis a...
Bailey SR, Wheeler-Jones C, Elliott J.5-hydroxytryptamine (5-HT; serotonin) is a potent vasoconstrictor of equine digital blood vessels and has been implicated in the pathogenesis of acute laminitis. Objective: The aims of this study were firstly to examine whether cells of the digital blood vessel wall exhibited an active uptake mechanism for 5-HT and to characterise its efficiency; and secondly, to study the potential inhibitory effect on this process of other amines, produced in the equine caecum. Methods: Confluent monolayers of equine digital vein endothelial cells (EDVEC) and equine digital vein smooth muscle cells (EDVSMC) ...
Govan JR, Sarasola P, Taylor DJ, Tatnell PJ, Russell NJ, Gacesa P.The isolation and characterization of a mucoid, alginate-producing strain of Pseudomonas aeruginosa from a nonhuman host, namely, in chondroids from an equine guttural pouch, is reported for the first time. Pure cultures of P. aeruginosa 12534 were isolated from a 17-month-old pony mare with a history of chronic bilateral mucopurulent nasal discharge from the right guttural pouch. Transmission electron microscopy of chondroids showed mucoid P. aeruginosa growing as microcolonies within a matrix of extracellular material. On the basis of expression of the mucoid phenotype under different growth...
Schmidtmann ET, Lloyd JE, Bobian RJ, Kumar R, Waggoner JW, Tabachinick WJ, Legg D.The blood feeding of mosquitoes and black flies from Hereford cattle and ponies treated with commercial formulations of permethrin was evaluated using an animal enclosure trap sample system that allowed comparison of insect blood-feeding levels between treated and nontreated animals. Blood feeding of both Aedes dorsalis Meigen and A. melanimon Dyar from heifers treated with pour-on concentrate and whole body spray treatments was reduced significantly by 79-88% at 4 d posttreatment, with apparent but not significant reductions of 61-68% at 11 d posttreatment. Simulium bivittatum Malloch and S. ...
Kleiboeker SB, Turnquist SE, Johnson PJ, Kreeger JM.In previous studies, novel putative viral pathogens designated that asinine herpesvirus 4 (AsHV4) and asinine herpesvirus 5 (AsHV5) were associated with fatal interstitial pneumonia in donkeys (Equus asinus). Nucleotide sequence analysis of a portion of the DNA polymerase gene identified these putative pathogens as herpesviruses and possibly as members of the Gammaherpesvirinae subfamily. Although similar to equine herpesvirus 2 (EHV2) and equine herpesvirus 5 (EHV5), sequence diversity was observed among the detected viruses. In this study, novel sequence is reported for a DNA-packaging prote...
White RT, Jelocnik M, Klukowski N, Haque MH, Sarker S.Chlamydia psittaci is a zoonotic pathogen that infects birds, humans, and other mammals. Notably, recent studies suggested the human-to-human transmission of C. psittaci, and this pathogen also causes equine reproductive loss in Australia. Molecular studies in Australia to date have focused on and described clonal sequence type (ST)24 strains infecting horses, wild psittacine, and humans. In contrast, the genetic identity of C. psittaci strains from captive psittacine hosts is scarce. In 2022, C. psittaci was detected in the faeces of a healthy captive blue-fronted parrot (Amazona aestiva). Ge...
Allegro AR, Barhoumi R, Bordin AI, Bray JM, Cohen ND.Rhodococcus equi is a soil saprophytic bacterium and intracellular pathogen that causes pneumonia in foals. Strains of R. equi that are virulent in foals contain a plasmid that encodes a virulence-associated protein A (VapA) necessary for replication in macrophages. Because other intracellular pathogens survive and replicate inside amoebae, we postulated that the VapA-bearing plasmid (pVAPA) confers a survival advantage for R. equi against environmental predators like amoebae. To test this hypothesis, we compared phagocytosis by and survival in Acanthamoeba castellanii of isogenic strains of p...
Figueredo LA, Cafarchia C, Otranto D.Fungi of the genus Geotrichum are commonly found in the environment and, in some circumstances, they may cause diseases in humans and animals. Although these fungi have been isolated from skin lesions of some animal species, their pathogenic role in horses remains uncertain. With the aim to investigate the role of Geotrichum candidum as etiological agent of dermatomycoses, a retrospective study of 64 horses presenting skin lesions and suspected to have fungal infections was carried out. For each animal, anamnestic data were recorded and fungal culture were performed using hair. Out of 64 cases...
Madden CR, Shih DS.Sequential passage of the tissue culture-adapted prototype strain of EIAV in fetal donkey dermal (FDD) cell cultures generated a virus stock which exhibits cytopathic effects in FDD cell cultures. In this study, the effects of the long terminal repeat (LTR) region on virus replication and cytopathogenicity were examined. The FDD-adapted virus LTR was found to contain a number of base pair mutations and a large insertion within the U3 region in comparison with the previously characterized LTR, lambda12. Transient gene expression studies showed that basal promoter activity, in FDD cell cultures,...
Lindsay DS, Mitchell SM, Yang J, Dubey JP, Gogal RM, Witonsky SG.Horses are considered accidental hosts for Sarcocystis neurona and they often develop severe neurological disease when infected with this parasite. Schizont stages develop in the central nervous system (CNS) and cause the neurological lesions associated with equine protozoal myeloencephalitis. The present study was done to examine the ability of S. neurona merozoites to penetrate and develop in equine peripheral blood leukocytes. These infected host cells might serve as a possible transport mechanism into the CNS. S. neurona merozoites penetrated equine leukocytes within 5 min of co-culture. I...
Bada R, Mittal KR, Higgins R.A total of 50 Actinobacillus suis isolates were studied for their biochemical and antigenic characteristics. Of them, 40 isolates originated from different tissues of diseased pigs, and the other ten isolates were from horses with respiratory problems. There was no major biochemical difference among equine and porcine A. suis isolates. Results of tube agglutination tests showed that porcines isolates were antigenically homogeneous while equine isolates were heterogeneous.
Collins MD, Lundström T, Welinder-Olsson C, Hansson I, Wattle O, Hudson RA, Falsen E.Phenotypic and phylogenetic studies were performed on four unidentified Gram-positive staining, catalase-negative, alpha-hemolytic Streptococcus-like organisms recovered from the teeth of horses. SDS PAGE analysis of whole-cell proteins and comparative 16S rRNA gene sequencing demonstrated the four strains were highly related to each other but that they did not correspond to any recognised species of the genus Streptococcus. Phylogenetic analysis based on 16S rRNA gene sequences showed the unidentified organisms form a hitherto unknown sub-line within the Streptococcus genus, displaying a clos...
Velineni S, Desoutter D, Perchec AM, Timoney JF.Streptococcus equi subspecies zooepidemicus (Sz) is a tonsillar and mucosal commensal of healthy horses with the potential to cause opportunistic infections of the distal respiratory tract stressed by virus infection, transportation, training or high temperature. The invasive clone varies from horse to horse with little evidence of lateral transmission in the group. Tonsillar isolates are non-mucoid although primary isolates from opportunist lower respiratory tract infections may initially be mucoid. In this study, a novel stably mucoid Sz (SzNC) from a clonal epizootic of respiratory disease ...
Maciel JF, Gressler LT, da Silveira BP, Dotto E, Balzan C, Matter LB, Siqueira FM, de Vargas APC.Data about phylogenetic classification of Escherichia coli colonizing calves, lambs and foals are routinely neglected and restricted to outdated methodologies, even in the context of antimicrobial susceptibility (AS) testing. Thus, the aim of this study was to determine the phylogenetic diversity and the AS profile of E. coli colony-forming units (CFUs) from faecal samples of healthy animals. Five CFUs of E. coli were randomly selected from each faecal culture of calves (n = 13), foals (n = 13) and lambs (n = 13), totalizing 195 CFUs phylo-typed by quadruplex PCR. The AS profile of five ...
Haines GR, Brown MP, Gronwall RR, Merritt KA, Baltzley LK.Pharmacokinetics and distribution of orbifloxacin into body fluids and endometrium was studied in 6 mares after intragastric (IG) administration at a single dose rate of 7.5 mg/kg body weight. Orbifloxacin concentrations were serially measured in serum, synovial fluid, peritoneal fluid, urine, cerebrospinal fluid, and endometrial tissues over 24 hours. Minimum inhibitory concentrations of orbifloxacin were determined for 120 equine pathogens over an 11-month period. The mean peak serum concentration (Cmax) was 2.41+/-0.30 microg/mL at 1.5 hours after administration and decreased to 0.17+/-0.01...
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...
Ivester KM, Adams SB, Moore GE, Van Sickle DC, Lescun TB.To determine synovial fluid gentamicin concentrations and evaluate adverse effects on the synovial membrane and articular cartilage of tarsocrural joints after implantation of a gentamicin-impregnated collagen sponge. Methods: 6 healthy adult mares. Methods: A purified bovine type I collagen sponge impregnated with 130 mg of gentamicin was implanted in the plantarolateral pouch of 1 tarsocrural joint of each horse, with the contralateral joint used as a sham-operated control joint. Gentamicin concentrations in synovial fluid and serum were determined for 120 hours after implantation by use of ...
Plasil M, Oppelt J, Klumplerova M, Bubenikova J, Vychodilova L, Janova E, Stejskalova K, Futas J, Knoll A, Leblond A, Mihalca AD, Horin P.The major histocompatibility complex (MHC) with its class I and II genes plays a crucial role in the immune response to pathogens by presenting oligopeptide antigens to various immune response effector cells. In order to counteract the vast variability of infectious agents, MHC class I and II genes usually retain high levels of SNPs mainly concentrated in the exons encoding the antigen binding sites. The aim of the study was to reveal new variability of selected MHC genes with a special focus on MHC class I physical haplotypes. Long-range NGS to was used to identify exon 2-exon 3 alleles in th...
Boyle AG, Rankin SC, D￮ LA, Morris D.Methicillin-resistant Staphylococcus aureus (MRSA) is recognized as a cause of nosocomial infections in both human and veterinary medicine. Studies that examine the nasopharynx and guttural pouches of the horse as carriage sites for MRSA have not been reported. Objective: MRSA colonizes the nasopharynx and guttural pouch of horses. To determine the prevalence of MRSA in equine nasopharyngeal wash (NPW) and guttural pouch lavage (GPL) samples in a field population of horses. Methods: One hundred seventy-eight samples (123 NPW and 55 GPL) from 108 horses. Methods: Prospective study. Samples were...
Lacerda MDSC, Wilson TM, Argenta VLS, de Araújo Pinto ÉG, E Macêdo JTSA, Soto-Blanco B, Keller KM, Ocampos Pedroso PM, Câmara ACL.The present report describes the clinical and pathological changes induced by the consumption of oats contaminated with Crotalaria spectabilis seeds by horses. Eighty horses were exposed to oats containing 10 g/kg of C. spectabilis seeds with 0.46% pyrrolizidine alkaloids, and 21 horses died within a 6-month period. Clinical signs included jaundice, apathy, a hypotonic tongue, ataxia, hyporexia, weight loss, aimless wandering, violent behavior, and proprioceptive deficits. Pathological findings were predominant in the liver and included periportal bridging fibrosis, megalocytosis, centrilobul...
Pavone S, Veronesi F, Piergili Fioretti D, Mandara MT.Gastrointestinal motility disorders represent a significant cause of morbidity and mortality in horses. Previously regarded as a non-pathogenic tapeworm, Anoplocephala perfoliata has been recently associated with equine colic. In this study, pathological changes related to A. perfoliata at the ileocecal junction were investigated in 31 slaughtered horses. Our results showed a significant relationship between parasitic burden and grading of histopathological lesions in both the mucosa and submucosa. Moreover, in infested horses, hypertrophy of the circular muscle layer was determined. Finally, ...
Haque RU.A technique for identifying and characterizing staphylococcal hemolysins by first separating them electrophoretically in barbital-buffered agar gel (pH 8.4) at 5 ma/cm for 2 hr and then determining their hemolytic activities by exposing them to human, horse, rabbit, and sheep erythrocytes is described. The alpha-hemolysin produced by a White variant of the Wood 46 strain of Staphylococcus aureus migrated 18 mm towards the cathode, and it lysed horse, rabbit, and sheep erythrocytes, whereas a Clear variant of the Wood 46 strain of S. aureus produced a lysin which migrated similarly to the alpha...
van Woensel PA, Goovaerts D, Markx D, Visser N.A mouse model was developed for testing the pathogenicity of equine herpes virus-1 (EHV-1) strains. The model was validated with EHV-1 strains that are known to be of a low or high pathogenicity in horses. From all parameters tested, the safety index, which was calculated from the body weights of the mice after infection, proved to be the best predictive parameter. When this parameter was used, good and reliable correlations were found with the pathogenicity of the EHV-1 strains in horses. This method enabled the differentiation between the two experimental EHV-1 strains whose genetic backgrou...
Satyam R, Janahi EM, Bhardwaj T, Somvanshi P, Haque S, Najm MZ.Usutu Virus (USUV; flavivirus) is a re-emerging pathogen invading the territories of European countries, Asia, and Africa. It is a mosquito-borne zoonotic virus with a bi-directional transmission route from animal to human and vice versa, and causes neurological disorders such as meningoencephalitis in bats, Homo sapiens, birds and horses. Due to limited availability of information about USUV and its deleterious effects on neural cells causing neurologic impairments, it becomes imperative to study this virus in detail to equip ourselves with a solution beforehand. The current study aims to ide...
