Pathogenicity in horses refers to the ability of infectious agents, such as bacteria, viruses, fungi, and parasites, to cause disease in equine hosts. This concept encompasses the mechanisms by which these pathogens invade, survive, and multiply within the horse, as well as the resulting clinical manifestations. Understanding pathogenicity involves studying the interaction between the pathogen and the horse's immune system, including the evasion strategies employed by the pathogen and the host's defensive responses. This page compiles peer-reviewed research studies and scholarly articles that investigate the factors influencing pathogenicity, the host-pathogen interactions, and the implications for disease management and prevention in equine populations.
Javed R, Taku AK, Gangil R, Sharma RK.The aim was to determine the occurrence of streptococci in equines in Jammu (R. S. Pura, Katra), characterization of Streptococci equi subsp. equi and Streptococcus equi subsp. zooepidemicus with respect to their virulence traits and to determine antibiotic sensitivity pattern of virulent Streptococcus isolates. Methods: A total of 96 samples were collected from both clinically affected animals (exhibiting signs of respiratory tract disease) and apparently healthy animals and were sent to laboratory. The organisms were isolated on Columbia nalidixic acid agar containing 5% sheep blood as well ...
Pinho MD, Erol E, Ribeiro-Gonçalves B, Mendes CI, Carriço JA, Matos SC, Preziuso S, Luebke-Becker A, Wieler LH, Melo-Cristino J, Ramirez M.The pathogenic role of beta-hemolytic Streptococcus dysgalactiae in the equine host is increasingly recognized. A collection of 108 Lancefield group C (n = 96) or L (n = 12) horse isolates recovered in the United States and in three European countries presented multilocus sequence typing (MLST) alleles, sequence types and emm types (only 56% of the isolates could be emm typed) that were, with few exceptions, distinct from those previously found in human Streptococcus dysgalactiae subsp. equisimilis. Characterization of a subset of horse isolates by multilocus sequence analysis (MLSA) a...
Dutkiewicz J, Mackiewicz B, Kinga Lemieszek M, Golec M, Milanowski J.Pantoea agglomerans, a bacterium associated with plants, is not an obligate infectious agent in humans. However, it could be a cause of opportunistic human infections, mostly by wound infection with plant material, or as a hospital-acquired infection, mostly in immunocompromised individuals. Wound infection with P. agglomerans usually follow piercing or laceration of skin with a plant thorn, wooden splinter or other plant material and subsequent inoculation of the plant-residing bacteria, mostly during performing of agricultural occupations and gardening, or children playing. Septic arthritis ...
Kalinowski M, Grądzki Z, Jarosz Ł, Kato K, Hieda Y, Kakuda T, Takai S.Rhodococcus equi is an important bacterial pathogen in foals up to 6 months old, widespread in horse farms all over the world. It was found that only virulent R. equi strains expressing 15-17 kDa virulence-associated protein (VapA) and having large virulence plasmid of 85-90 kb containing vapA gene are pathogenic for horses. To date, 12 plasmid types have been reported in VapA positive strains from horses. There are no data concerning plasmid types of Polish field R. equi strains isolated from horses and horse farm environment. The aim of the study is to determine plasmid profiles of virulent ...
Nemoto M, Bannai H, Tsujimura K, Yamanaka T, Kondo T.A Getah virus strain isolated during an outbreak in racehorses in Japan in 2014 (14-I-605) was compared with the vaccine strain isolated in 1978 (MI-110). A comparison of the genome sequences of these strains revealed seven amino acid substitutions in non-structural protein 3, and one or two substitutions in each of other non-structural proteins. In contrast, the structural proteins were highly conserved (99.8-99.9 % amino acid sequence identity). Horse antisera raised against the MI-110 strain showed similar virus-neutralization titers against both MI-110 and 14-I-605 strains (512 and 256, r...
Roy Chowdhury P, DeMaere M, Chapman T, Worden P, Charles IG, Darling AE, Djordjevic SP.Clostridium difficile infections (CDI) are a significant health problem to humans and food animals. Clostridial toxins ToxA and ToxB encoded by genes tcdA and tcdB are located on a pathogenicity locus known as the PaLoc and are the major virulence factors of C. difficile. While toxin-negative strains of C. difficile are often isolated from faeces of animals and patients suffering from CDI, they are not considered to play a role in disease. Toxin-negative strains of C. difficile have been used successfully to treat recurring CDI but their propensity to acquire the PaLoc via lateral gene transfe...
Sanna G, Pipia AP, Tamponi C, Manca R, Varcasia A, Traversa D, Scala A.Intestinal strongyles (IS) are the most important parasites of equids, due to their high prevalence worldwide, pathogenicity and the spread of drug-resistant populations. Despite the large number of horses bred in Sardinia Island, Italy, no data are available on the efficacy of anthelmintic compounds in the control of horse strongylosis. Therefore the aim of the present study was to evaluate the efficacy of five commercial anthelmintic formulations containing fenbendazole (FBZ), pyrantel (PYR), moxidectin (MOX) and two ivermectin formulations (IVM1 and IVM2) against IS in Sardinia by performin...
Mehdizadeh Gohari I, Kropinski AM, Weese SJ, Parreira VR, Whitehead AE, Boerlin P, Prescott JF.The recent discovery of a novel beta-pore-forming toxin, NetF, which is strongly associated with canine and foal necrotizing enteritis should improve our understanding of the role of type A Clostridium perfringens associated disease in these animals. The current study presents the complete genome sequence of two netF-positive strains, JFP55 and JFP838, which were recovered from cases of foal necrotizing enteritis and canine hemorrhagic gastroenteritis, respectively. Genome sequencing was done using Single Molecule, Real-Time (SMRT) technology-PacBio and Illumina Hiseq2000. The JFP55 and JFP838...
Wang XF, Lin YZ, Li Q, Liu Q, Zhao WW, Du C, Chen J, Wang X, Zhou JH.The equine infectious anemia virus (EIAV) vaccine is the only attenuated lentiviral vaccine applied on a large scale that has been shown to be effective in controlling the prevalence of EIA in China. This vaccine was developed by successive passaging of a field-isolated virulent strain in different hosts and cultivated cells. To explore the molecular basis for the phenotype alteration of this vaccine strain, we systematically analyzed its genomic evolution during vaccine development. Results: Sequence analysis revealed that the genetic distance between the wild-type strain and six representati...
Aleman M, Shapiro K, Sisó S, Williams DC, Rejmanek D, Aguilar B, Conrad PA.Recent reports of Sarcocystis fayeri-induced toxicity in people consuming horse meat warrant investigation on the prevalence and molecular characterization of Sarcocystis spp. infection in horses. Sarcocysts in skeletal muscle of horses have been commonly regarded as an incidental finding. In this study, we investigated the prevalence of sarcocysts in skeletal muscle of horses with neuromuscular disease. Our findings indicated that S. fayeri infection was common in young mature horses with neuromuscular disease and could be associated with myopathic and neurogenic processes. The number of in...
Lotstra RJ, van den Broek J, Power T, Marr CM, Wijnberg ID.Atrial fibrillation is a common equine arrhythmia. Quinidine alone, or with digoxin are common treatments. Studies on outcome in Warmblood populations in which duration of the AF is often unknown are limited. Objective: To identify the factors that are associated with the success of full treatment cardioversion with oral medication, and establish whether there are differences in these factors between institutions. Methods: Retrospective case series using patient records of Equine University Clinic of Utrecht University and Rossdales Equine Hospital, Newmarket. Methods: Forty-nine horses treate...
Harris SR, Robinson C, Steward KF, Webb KS, Paillot R, Parkhill J, Holden MT, Waller AS.Strangles, the most frequently diagnosed infectious disease of horses worldwide, is caused by Streptococcus equi. Despite its prevalence, the global diversity and mechanisms underlying the evolution of S. equi as a host-restricted pathogen remain poorly understood. Here, we define the global population structure of this important pathogen and reveal a population replacement in the late 19th or early 20th Century. Our data reveal a dynamic genome that continues to mutate and decay, but also to amplify and acquire genes despite the organism having lost its natural competence and become host-rest...
Stephenson N, Hodzic E, Mapes S, Rejmanek D, Foley J.Anaplasma phagocytophilum is a tick-transmitted bacterial pathogen of humans and animals comprising strains that cause clinical disease in people, dogs and horses (the pathogenic A. phagocytophilum "genospecies") and more distantly related strains. A rodent-adapted genospecies named DU1, found primarily in woodrats, is unable to infect horses. We developed a real-time PCR (RT-PCR) assay, which targets an 85 base pair region of the ank gene and is specific for the pathogenic genospecies of A. phagocytophilum from North America. Thirty DNA samples from A. phagocytophilum RT-PCR-positive rodents ...
Rossi SL, Russell-Lodrigue KE, Killeen SZ, Wang E, Leal G, Bergren NA, Vinet-Oliphant H, Weaver SC, Roy CJ.Venezuelan equine encephalitis virus (VEEV) is an arbovirus endemic to the Americas that is responsible for severe, sometimes fatal, disease in humans and horses. We previously described an IRES-based VEE vaccine candidate based up the IE serotype that offers complete protection against a lethal subtype IE VEEV challenge in mice. Here we demonstrate the IRES-based vaccine's ability to protect against febrile disease in cynomolgus macaques. Vaccination was well tolerated and elicited robust neutralizing antibody titers noticed as early as day 14. Moreover, complete protection from disease chara...
McLean R, Rash NL, Robinson C, Waller AS, Paillot R.Streptococcus equi subspecies equi (S. equi) is the causative agent of strangles, a highly contagious upper respiratory disease of equids. Streptococcus equi produces superantigens (sAgs), which are thought to contribute to strangles pathogenicity through non-specific T-cell activation and pro-inflammatory response. Streptococcus equi infection induces abscesses in the lymph nodes of the head and neck. In some individuals, some abscess material remains into the guttural pouch and inspissates over time to form chondroids which can harbour live S. equi. The aim of this study was to determine...
Okoko T, Blagova EV, Whittingham JL, Dover LG, Wilkinson AJ.Virulence and host range in Rhodococcus equi depends on the variable pathogenicity island of their virulence plasmids. Notable gene products are a family of small secreted virulence-associated proteins (Vaps) that are critical to intramacrophagic proliferation. Equine-adapted strains, which cause severe pyogranulomatous pneumonia in foals, produce a cell-associated VapA that is necessary for virulence, alongside five other secreted homologues. In the absence of biochemical insight, attention has turned to the structures of these proteins to develop a functional hypothesis. Recent studies have ...
Bouzalas IG, Diakakis N, Chaintoutis SC, Brellou GD, Papanastassopoulou M, Danis K, Vlemmas I, Seuberlich T, Dovas CI.During the summer of 2010, an outbreak of West Nile virus (WNV) infections attributed to a lineage 2 WNV strain was reported among humans and horses in Central Macedonia, Northern Greece. Here, the clinical and laboratory investigation of horses that showed severe neurological signs due to WNV infection is being described. Specifically, between August and September 2010, 17 horses with neurological signs were detected. WNV infection was confirmed in all 17 clinical cases by applying laboratory testing. The duration of WNV-specific IgM antibodies in sera obtained from seven of the clinically af...
Srivastava A, Singh BN, Deepak D, Rawat AK, Singh BR.The discovery of quorum-sensing (QS) systems regulating antibiotic resistance and virulence factors (VFs) has afforded a novel opportunity to prevent bacterial pathogenicity. Dietary molecules have been demonstrated to attenuate QS circuits of bacteria. But, to our knowledge, no study exploring the potential of colostrum hexasaccharide (CHS) in regulating QS systems has been published. In this study, we analyzed CHS for inhibiting QS signaling in Staphylococcus aureus. We isolated and characterized CHS from mare colostrum by high-performance thin-layer chromatography (HPTLC), reverse-phase hig...
Wang XF, Wang S, Liu Q, Lin YZ, Du C, Tang YD, Na L, Wang X, Zhou JH.Equine infectious anemia virus (EIAV) is a member of the Lentivirus genus in the Retroviridae family that exhibits a genomic structure similar to that of HIV-1. The S2 accessory proteins play important roles in viral replication in vivo and in viral pathogenicity; however, studies on S2 evolution in vivo are limited. This study analyzed the evolutionary characteristics of the S2 gene of a pathogenic EIAV strain, EIAVLN40, in four experimentally infected horses. The results demonstrated that 14.7% (10 of 68 residues) of the stable amino acid mutations occurred longitudinally in S2 during a 150-...
Alymova IV, York IA, McCullers JA.PB1-F2 protein, expressed from an alternative reading frame of most influenza A virus (IAV) PB1 segments, may possess specific residues associated with enhanced inflammation (L62, R75, R79, and L82) and cytotoxicity (I68, L69, and V70). These residues were shown to increase the pathogenicity of primary viral and secondary bacterial infections in a mouse model. In contrast to human seasonal influenza strains, virulence-associated residues are present in PB1-F2 proteins from pandemic H1N1 1918, H2N2 1957, and H3N2 1968, and highly pathogenic H5N1 strains, suggesting their contribution to viruses...
Di Sabatino D, Bruno R, Sauro F, Danzetta ML, Cito F, Iannetti S, Narcisi V, De Massis F, Calistri P.West Nile virus (WNV) transmission has been confirmed in the last four years in Europe and in the Mediterranean Basin. An increasing concern towards West Nile disease (WND) has been observed due to the high number of human and animal cases reported in these areas confirming the importance of this zoonosis. A new epidemiological scenario is currently emerging: although new introductions of the virus from abroad are always possible, confirming the epidemiological role played by migratory birds, the infection endemisation in some European territories today is a reality supported by the constant r...
Timoney JF, Suther P, Velineni S, Artiushin SC.Resistance to phagocytosis is a crucial virulence property of Streptococcus equi (Streptococcus equi subsp. equi; Se), the cause of equine strangles. The contribution and interdependence of capsule and SeM to killing in equine blood and neutrophils were investigated in naturally occurring strains of Se. Strains CF32, SF463 were capsule and SeM positive, strains Lex90, Lex93 were capsule negative and SeM positive and strains Se19, Se1-8 were capsule positive and SeM deficient. Phagocytosis and killing of Se19, Se1-8, Lex90 and Lex93 in equine blood and by neutrophils suspended in serum were sig...
Velineni S, Timoney JF.Streptococcus zooepidemicus causes opportunist respiratory and other infections in the horse. Capsule expression is highly variable and known to affect resistance to phagocytosis. Most clinical isolates producing small, dry colonies at 37°C produce mucoid colonies at temperatures below 35°C. Objective: The aim was to understand the molecular basis of increased capsule expression by equine isolates of S. zooepidemicus at temperatures lower than 35°C. Methods: Cross-sectional observational study. Methods: Capsule production by groups of equine S. zooepidemicus strains was determined at 23, ...
Bingham J, Payne J, Harper J, Frazer L, Eastwood S, Wilson S, Lowther S, Lunt R, Warner S, Carr M, Hall RA, Durr PA.West Nile virus (WNV; family Flaviviridae; genus Flavivirus) group members are an important cause of viral meningoencephalitis in some areas of the world. They exhibit marked variation in pathogenicity, with some viral lineages (such as those from North America) causing high prevalence of severe neurological disease, whilst others (such as Australian Kunjin virus) rarely cause disease. The aim of this study was to characterize WNV disease in a mouse model and to elucidate the pathogenetic features that distinguish disease variation. Tenfold dilutions of five WNV strains (New York 1999, MRM16 a...
González-Iglesias P, Scortti M, MacArthur I, Hapeshi A, Rodriguez H, Prescott JF, Vazquez-Boland JA.The pathogenic actinomycete Rhodococcus equi causes severe purulent lung infections in foals and immunocompromised people. Although relatively unsusceptible to R. equi, mice are widely used for in vivo studies with this pathogen. The most commonly employed mouse model is based on systemic (intravenous) infection and determination of R. equi burdens in spleen and liver. Here, we investigated the murine lung for experimental infection studies with R. equi. Using a 10(7)CFU intranasal challenge in BALB/c mice, virulent R. equi consistently survived in quantifiable numbers up to 10 days in the lun...
Fernandez-Fuente M, Martin-Duque P, Vassaux G, Brown SC, Muntoni F, Terracciano CM, Piercy RJ.Several human and animal myopathies, such as malignant hyperthermia (MH), central core disease and equine recurrent exertional rhabdomyolysis (RER) are confirmed or thought to be associated with dysfunction of skeletal muscle calcium regulation. For some patients in whom the genetic cause is unknown, or when mutational analysis reveals genetic variants with unclear pathogenicity, defects are further studied through use of muscle histopathology and in vitro contraction tests, the latter in particular, when assessing responses to ryanodine receptor agonists, such as caffeine. However, since musc...
Hébert L, Bidaud P, Goux D, Benachour A, Laugier C, Petry S.Lysozyme is an important and widespread component of the innate immune response that constitutes the first line of defense against bacterial pathogens. The bactericidal effect of this enzyme relies on its capacity to hydrolyze the bacterial cell wall and also on a nonenzymatic mechanism involving its cationic antimicrobial peptide (CAMP) properties, which leads to membrane permeabilization. In this paper, we report our findings on the lysozyme resistance ability of Rhodococcus equi, a pulmonary pathogen of young foals and, more recently, of immunocompromised patients, whose pathogenic capacity...
Ma G, Azab W, Osterrieder N.The equine herpesviruses type 1 (EHV-1) and 4 (EHV-4) are ubiquitous pathogens that affect horse populations on all continents. Despite widespread vaccination, EHV-1 and EHV-4 infections remain a permanent risk. While the two viruses share a high degree of genetic and antigenic similarity, they differ significantly in host range and pathogenicity. Compared to EHV-4, which mainly infects horses and causes respiratory disease, EHV-1 has a broader host range and can result in respiratory disease, abortions, neonatal death, and equine herpesvirusmyeloencephalopathy (EHM). Recent studies have eluci...
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...
Gómez-Sanz E, Simón C, Ortega C, Gómez P, Lozano C, Zarazaga M, Torres C.Eight coagulase-positive staphylococci from equines with different pathologies obtained between 2005 and 2011 were investigated. Isolates were characterized by different molecular techniques (spa-, agr-, MLST), and clonal relatedness of strains was investigated by ApaI and SmaI PFGE. Anti-microbial resistance and virulence profiles were determined. Six isolates were identified as Staphylococcus aureus, and two as Staphylococcus pseudintermedius. Of these, four isolates were methicillin-resistant S. aureus (MRSA) ST398 and one S. pseudintermedius was mecA positive and typed as ST68. One MRSA ...
Whetter L, Archambault D, Perry S, Gazit A, Coggins L, Yaniv A, Clabough D, Dahlberg J, Fuller F, Tronick S.A full-length molecular clone of equine infectious anemia virus (EIAV) was isolated from a persistently infected canine fetal thymus cell line (Cf2Th). Upon transfection of equine dermis cells, the clone, designated CL22, yielded infectious EIAV particles (CL22-V) that replicated in vitro in both Cf2Th cells and an equine dermis cell strain. Horses infected with CL22-V developed an antibody response to viral proteins and possessed viral DNA in peripheral blood mononuclear cells, as determined by polymerase chain reaction assays. In addition, horses infected with CL22-V became persistently infe...
Pinho MD, Erol E, Ribeiro-Gonçalves B, Mendes CI, Carriço JA, Matos SC, Preziuso S, Luebke-Becker A, Wieler LH, Melo-Cristino J, Ramirez M.The pathogenic role of beta-hemolytic Streptococcus dysgalactiae in the equine host is increasingly recognized. A collection of 108 Lancefield group C (n = 96) or L (n = 12) horse isolates recovered in the United States and in three European countries presented multilocus sequence typing (MLST) alleles, sequence types and emm types (only 56% of the isolates could be emm typed) that were, with few exceptions, distinct from those previously found in human Streptococcus dysgalactiae subsp. equisimilis. Characterization of a subset of horse isolates by multilocus sequence analysis (MLSA) a...
Flanagan J, Collin N, Timoney J, Mitchell T, Mumford JA, Chanter N.The haemolytic activity of Streptococcus equi, the cause of equine strangles, was characterized. Production of haemolysin in Todd Hewitt broth was dependent on an equine serum supplement and the logarithmic phase of growth after which activity declined sharply. RNA core also induced haemolysin production from cells harvested at the end of the logarithmic phase of growth. Haemolysis was not affected by cholesterol, was only slightly increased in reducing conditions and was completely inactivated by trypan blue, identifying the haemolytic activity as streptolysin S-like (SLS-like). Purification ...
Wang XF, Lin YZ, Li Q, Liu Q, Zhao WW, Du C, Chen J, Wang X, Zhou JH.The equine infectious anemia virus (EIAV) vaccine is the only attenuated lentiviral vaccine applied on a large scale that has been shown to be effective in controlling the prevalence of EIA in China. This vaccine was developed by successive passaging of a field-isolated virulent strain in different hosts and cultivated cells. To explore the molecular basis for the phenotype alteration of this vaccine strain, we systematically analyzed its genomic evolution during vaccine development. Results: Sequence analysis revealed that the genetic distance between the wild-type strain and six representati...
Ciarlet M, I a P, Conner ME, Liprandi F.We have sequenced the genes encoding the inner capsid protein VP6 and the outer capsid glycoprotein VP7 of the subgroup (SG) I equine rotavirus strain H-1 (P9[7], G5). The VP6 and VP7 proteins of the equine rotavirus strain H-1 shared a high degree of sequence and deduced amino acid identity with SG I porcine strains and serotype G5 porcine strains, respectively. Previous sequence analyses of the genes encoding the outer capsid spike protein VP4 and the nonstructural proteins NSP1 and NSP4 of equine H-1 strain also revealed a high degree of sequence and deduced amino acid homology with the pro...
Walton TE, Alvarez O, Buckwalter RM, Johnson KM.Ten horses (Equus caballus) were vaccinated with strain TC-83 Venezuelan equine encephalomyelitis (VEE) virus vaccine. Febrile responses and leukopenia due to a reduction of lymphocytes and neutrophils were observed in all animals. Viremias were demonstrable in eight horses, with a maximum of 10(3.5) median tissue culture infectious dose units per ml of serum in two horses. Clinical illness with depression and anorexia were observed in five horses. Neutralizing (N), hemagglutination-inhibiting, and complement-fixing antibodies to the vaccine virus were demonstrable by 5, 6.5, and 7 days, respe...
Mehdizadeh Gohari I, Unterer S, Whitehead AE, Prescott JF.The role of type A in canine acute hemorrhagic diarrhea syndrome and foal necrotizing enteritis is poorly characterized. However, a highly significant association between the presence of novel toxigenic and these specific enteric diseases has been described. These novel toxigenic strains produce 3 novel putative toxins, which have been designated NetE, NetF, and NetG. Although not conclusively demonstrated, current evidence suggests that NetF is likely the major virulence factor in strains responsible for canine acute hemorrhagic diarrhea syndrome and foal necrotizing enteritis. NetF is a be...
Cook SJ, Cook RF, Montelaro RC, Issel CJ.Most in vivo studies with equine infectious anemia virus (EIAV) have been performed in horses and ponies (Equus caballus) with little published information available detailing the clinical responses of donkeys (Equus asinus) to infection with this virus. Consequently, donkeys were inoculated with two strains of EIAV (EIAV(PV) and EIAV(WY)) which have been documented to produce disease in E. caballus. Four ponies, 561, 562, 564 and 567 and two donkeys, 3 and 5 were infected with EIAV(PV) and one horse (94-10) and one donkey (4) were infected with EIAV(WY). Although the horse and ponies all expe...
Matsumura T, O'Callaghan DJ, Kondo T, Kamada M.The virulence of the cell culture adapted KyA strain of equine herpesvirus type 1 (EHV-1), which lacks at least six genes by deletions in its genome, was assessed by intranasal inoculation of six young horses that were serologically negative for EHV-1. No horses showed clinical signs, and a neutralizing antibody response against EHV-1 was detected in two horses which had antibodies against EHV-4 prior to the inoculation. A challenge experiment using a highly virulent strain of EHV-1 conducted 4 weeks later against 4 of the 6 horses inoculated intranasally with the KyA strain and 2 control hors...
Montagnier L.Recent data indicate that the lymphadenopathy-associated virus (LAV) is morphologically similar to animal lentiviruses, such as equine infectious anemia and visna viruses. This finding, together with the cross-reactivity of the core proteins of LAV with those of the equine infectious anemia virus and a similarity in genome structure and biological properties, allows LAV to be placed in the retroviral subfamily of Lentivirinae. Molecular data indicate a high degree of genetic variation of the virus, especially in the envelope gene, which have important implications for the origin of the virus (...
Willingham-Lane JM, Berghaus LJ, Giguère S, Hondalus MK.The soil-dwelling, saprophytic actinomycete is a multihost, facultative intracellular pathogen of macrophages. When inhaled by susceptible foals, it causes severe bronchopneumonia. It is also a pathogen of pigs, which may develop submaxillary lymphadenitis upon exposure. isolates obtained from foals and pigs possess conjugative plasmids housing a pathogenicity island (PAI) containing a novel family of genes of unknown function called the virulence-associated protein or family. The PAI regions of the equine and swine plasmids differ in gene composition, with equine isolates possessing six ...
Rothschild CM, Oaks JL, Schaupp JK, Rurangirwa FR, Sellon DC, Hines MT.Helcococcus ovis, a recently described organism cultured from sheep, was isolated in pure culture from a pulmonary abscess in a horse. This is the first report of this organism in horses and the first report in veterinary medicine to clearly demonstrate a pathogenic role for this organism.
Takai S, Takeda K, Nakano Y, Karasawa T, Furugoori J, Sasaki Y, Tsubaki S, Higuchi T, Anzai T, Wada R, Kamada M.To investigate the emergence of rifampin resistance in Rhodococcus equi strains isolated from foals and their environment in Japan, we compared the in vitro antimicrobial susceptibilities to rifampin of 640 isolates from 64 infected foals and 98 soil isolates from their horse-breeding farms. As a control, 39 human isolates from patients with and without AIDS were also tested for susceptibility to rifampin. All of the isolates showed rifampin sensitivity, except isolates from one infected foal and two patients with AIDS that showed rifampin resistance. To investigate the emergence of rifampin-r...
Miyoshi S, Sasahara K, Akamatsu S, Rahman MM, Katsu T, Tomochika K, Shinoda S.Vibrio mimicus is a causative agent of human gastroenteritis. This pathogen secretes a pore-forming toxin, V. mimicus hemolysin (VMH), which causes hemolysis by three sequential steps: binding to an erythrocyte membrane, formation of a transmembrane pore, and disruption of the cell membrane. VMH with a molecular mass of 63 kDa was purified by ammonium sulfate precipitation and column chromatography with phenyl Sepharose HP and Superose 6 HR. The hemolytic reaction induced by VMH continued up to disruption of all erythrocytes in the assay system. Moreover, VMH that bound preliminarily to erythr...
Bouzalas IG, Diakakis N, Chaintoutis SC, Brellou GD, Papanastassopoulou M, Danis K, Vlemmas I, Seuberlich T, Dovas CI.During the summer of 2010, an outbreak of West Nile virus (WNV) infections attributed to a lineage 2 WNV strain was reported among humans and horses in Central Macedonia, Northern Greece. Here, the clinical and laboratory investigation of horses that showed severe neurological signs due to WNV infection is being described. Specifically, between August and September 2010, 17 horses with neurological signs were detected. WNV infection was confirmed in all 17 clinical cases by applying laboratory testing. The duration of WNV-specific IgM antibodies in sera obtained from seven of the clinically af...
Liang H, He X, Shen RX, Shen T, Tong X, Ma Y, Xiang WH, Zhang XY, Shao YM.The Chinese equine infectious anemia virus (EIAV) donkey-leukocyte attenuated vaccine (DLV) provides a unique natural model system to study the attenuation mechanism and immunological control of lentivirus replication. Critical consensus mutations were identified between virulent Chinese EIAV strains and vaccine strains. Based on a full-length infectious clone of EIAV vaccine strain pLGFD3, two molecular clones, mFD5-4-7 and mFD7-2-11, were successfully constructed, in which 4 and 6 critical consensus mutations in the env gene of the vaccine strain were point-mutated to the wild-type sequence,...
Taniguchi A, Fukushi H, Matsumura T, Yanai T, Masegi T, Hirai K.Pathogenicity of equine herpesvirus 9 (EHV-9), a new type of equine herpesvirus isolated from Gazella thomsoni, in horses was investigated by intranasal inoculation of EHV-9 (10(7) pfu) to two conventionally reared 8-months old half-bred weanling horses. Fever higher than 39 degrees C was recorded. Virus was recovered from nasal swabs and peripheral blood mononuclear cells. Both horses developed neutralizing antibody to EHV-9. Perivascular infiltration of mononuclear cells and glial reaction were found in the olfactory and limbic systems. The results suggested that EHV-9 has a pathogenicity in...
Tzipori S, Hayes J, Sims L, Withers M.Streptococcus durans was isolated from a foal with profuse watery diarrhea and caused a similar syndrome when inoculated into foals via the orogastric route. The most consistent and striking histological feature was the extensive colonization of the mucosal surface of the small intestine by S. durans. Associated mucosal changes were mild to modeate, and brush border lactase and alkaline phosphatase production were depressed. S. durans also induced acute diarrhea in young gnotobiotic piglets. Mucosal changes were mild and, as with foals, the mucosal surface of the small intestine was colonized ...
Takai S, Anzai T, Fujita Y, Akita O, Shoda M, Tsubaki S, Wada R.Rhodococcus equi strains of intermediate virulence (IMV) for mice possess a 20kDa protein designated Virulence Associated Protein B (VapB) and a virulence plasmid of 79-100kb, and can be recovered from the submaxillary lymph nodes of pigs. The pathogenicity of such R. equi strains for foals is unknown. In this study, two foals, 42 and 43 days of age, were infected intratracheally with 10(6) and 10(9) cells of R. equi IMV strain A5, respectively. The foal infected with 10(9) cells of strain A5 became clinically ill, with the onset of illness (pyrexia and depression) occurring 21 days after inoc...
Slater JD, Gibson JS, Field HJ.Both intranasal (i.n.) and intracerebral (i.c.) inoculation of mice with wild-type equine herpesvirus type 1 (wt EHV-1) caused clinical signs and mortality. Virus could be recovered from target organs (turbinates, lungs and blood) for several days. By contrast, the thymidine kinase (TK)-deficient deletion mutant PR1 produced markedly less clinical disease following both i.n. and i.c. inoculation, and, in particular, no mortality occurred. PR1 did, however, establish productive infections following either route of inoculation. High titres of virus were recovered from target organs although viru...
Dubey JP, Bauer C.There is considerable confusion concerning validity of Eimeria species in equids, and endogenous developmental stages and pathogenicity of equid Eimeria. This paper summarizes worldwide information on history, structure, life cycle, pathogenicity, prevalence, epidemiology, and diagnosis of Eimeria infections in equids. The following conclusions were drawn. Although three species of Eimeria; E. solipedum, E. uninugulata, and E. leuckarti were named from horses, only E. leuckarti is a valid species infecting equids, including horses, donkeys and zebra. We consider E. solipedum, E. uninugulata an...
Journal of medical entomologyAugust 9, 2006
Volume 43, Issue 4 762-773 doi: 10.1603/0022-2585(2006)43[762:DACOBB]2.0.CO;2
Morshed MG, Scott JD, Fernando K, Geddes G, McNabb A, Mak S, Durden LA.The blacklegged tick, Ixodes scapularis Say (Acari: Ixodidae), has a wide geographical distribution in Ontario, Canada, with a detected range extending at least as far north as the 50th parallel. Our data of 591 adult I. scapularis submissions collected from domestic animals (canines, felines, and equines) and humans during a 10-yr period (1993-2002) discloses a monthly questing activity in Ontario that peaks in May and October. The Lyme disease spirochete Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwalt & Brenner was detected in 12.9% of I. scapularis adults collected from domesti...
Cho HC, Hwang S, Kim EM, Park YJ, Shin SU, Jang DH, Chae JS, Choi KS. is an obligate intracellular zoonotic bacterium with a global distribution. This study was conducted to investigate the prevalence of in different animals and to assess the potential role of these species as reservoirs of infection and transmission to humans. A total of 592 blood samples (105 beef cattle, 61 dairy cattle, 110 Korean native goats, 83 Boer goats, and 233 horses) were collected in the Republic of Korea (ROK). The DNA was detected from blood samples using the transposon-like repetitive region () by PCR method. The results showed that 22.7% of the Korean-native goats, 16.4% of t...
Santos RG, Hurtado R, Gomes LGR, Profeta R, Rifici C, Attili AR, Spier SJ, Mazzullo G, Morais-Rodrigues F, Gomide ACP, Brenig B, Gala-García A....Bacteria of the genusGlutamicibacterare considered ubiquitous because they can be found in soil, water and air. They have already been isolated from different habitats, including different types of soil, clinical samples, cheese and plants. Glutamicibacter creatinolyticus is a Gram-positive bacterium important to various biotechnological processes, however, as a pathogen it is associated to urinary tract infections and bacteremia. Recently,Glutamicibacter creatinolyticusLGCM 259 was isolated from a mare, which displayed several diffuse subcutaneous nodules with heavy vascularization. In this s...
Devriese LA, Nzuambe D, Godard C.One hundred and twenty eight strains of Staphylococcus from lesions, mostly of the skin, in horses were identified and compared with 29 strains isolated from the healthy skin. The pathogenic species Staphylococcus aureus, S. intermedius and S. hyicus were found almost exclusively in lesions. Other species such as S. xylosus and S. sciuri were more frequently found on the healthy skin than in lesions. The S. aureus strains formed a very heterogeneous collection. Many of these strains were staphylokinase positive and rapidly coagulated bovine plasma. Such strains are rarely found in other animal...
Borchers K, Wolfinger U, Goltz M, Broll H, Ludwig H.Equine herpesvirus type 2 (EHV-2) is a slow-growing, cytopathogenic gammaherpesvirus, which is suggested to be ubiquitous in the equine population. However, its precise role as a pathogen and its tissue tropism remains uncertain. To estimate the prevalence of EHV-2 in Germany and to investigate the possible pathogenicity of the virus, peripheral blood leucocytes (PBL) from 172 horses were examined for EHV-2 DNA by a sensitive and specific nested PCR based on the EcoRI-N genomic fragment and by classical cocultivation. PBL samples from 51% of the horses were positive by PCR and virus was isolat...
Cook RF, Cook SJ, Berger SL, Leroux C, Ghabrial NN, Gantz M, Bolin PS, Mousel MR, Montelaro RC, Issel CJ.Pathogenicity was reportedly restored to an avirulent molecular clone of equine infectious anemia virus (EIAV) by substitution of 3' sequences from the pathogenic variant strain (EIAV(PV)). However, the incidence of disease in horses/ponies was found to be significantly lower (P = 0.016) with the chimeric clone (EIAV(UK)) than with EIAV(PV). This was attributable to 3' rather than 5' regions of the proviral genome, where EIAV(UK) differs from the consensus EIAV(PV) sequence by having a 68-bp duplication in the 3' LTR and arginine (R(103)) rather than tryptophan (W(103)) at position 103 in the ...
Pei Y, Parreira V, Nicholson VM, Prescott JF.Rhodococcus equi can cause severe or fatal pneumonia in foals as well as in immunocompromised animals and humans. Its ability to persist in macrophages is fundamental to how it causes disease, but the basis of this is poorly understood. To examine further the general application of a recently developed system of targeted gene mutation and to assess the importance of different genes in resistance to innate immune defenses, we disrupted the genes encoding high-temperature requirement A (htrA), nitrate reductase (narG), peptidase D (pepD), phosphoribosylaminoimidazole-succinocarboxamide synthase ...
Little SV, Hillhouse AE, Lawhon SD, Bryan LK.While Staphylococcus aureus is associated with significant morbidity and mortality in equids (horses, donkeys, and mules), few studies have performed whole-genome sequencing to fully categorize large collections of equine isolates. Such sequencing allows for a comprehensive analysis of the genetic lineage and relationships of isolates, as well as the virulence genes present in each, which can be important for understanding the epidemiology of strains and their range of infections. Seventy-two clinical Staphylococcus aureus isolates from equids were collected at the Texas A&M University Veterin...
Berghaus LJ, Giguère S, Bordin AI, Cohen ND.Rhodococcus equi is a common cause of pneumonia in foals and an opportunistic pathogen in immunosuppressed people. The ability of R. equi to survive and replicate in macrophages is the basis of its pathogenicity. Limited knowledge about the role of cytokines in host defense against R. equi comes from studies in mice and the role of cytokines in intracellular survival of R. equi in equine macrophages is unknown. The objectives of this study were to determine the effect of priming with interferon (IFN)-γ, interleukin (IL)-1β, IL-4, IL-6, IL-10, or tumor necrosis factor (TNF)-α at various conc...
