Infections in horses encompass a range of diseases caused by various pathogens, including bacteria, viruses, fungi, and parasites. These infections can affect different systems within the horse, such as the respiratory, gastrointestinal, and integumentary systems, leading to a variety of clinical signs depending on the pathogen and the severity of the infection. Common infectious diseases in horses include equine influenza, strangles, and equine herpesvirus. Diagnosis often involves clinical examination, laboratory testing, and sometimes imaging, to identify the causative agent and assess the extent of the disease. Treatment strategies may include antimicrobial therapy, supportive care, and preventive measures such as vaccination and biosecurity practices. This page aggregates peer-reviewed research studies and scholarly articles that explore the pathogenesis, diagnosis, treatment, and prevention of infectious diseases in equine populations.
Moeller BC, Clifford A, Emery RT, Alarcio G, Favro G, Arthur RM.Zilpaterol is a β -adrenergic agonist and a repartitioning agent that has a high potential for abuse in equine performance athletes. Analysis of zilpaterol in hair is an alternative sampling matrix that extends detection time periods beyond those found in urine or blood samples. Our laboratory has been screening for zilpaterol in hair for many years and recently detected and confirmed its presence in official samples. Accordingly, a liquid chromatography-mass spectrometry method was developed and validated to detect and confirm zilpaterol in equine hair. Briefly, equine hair was decontaminate...
Vissani MA, Damiani AM, Barrandeguy ME.Equine coital exanthema (ECE) is a highly contagious, venereally-transmitted mucocutaneous disease, characterized by the formation of papules, vesicles, pustules and ulcers on the external genital organs of mares and stallions, and caused by (EHV-3). The infection is endemic worldwide and the virus is transmitted mainly through direct contact during sexual intercourse and by contaminated instruments during reproductive maneuvers in breeding facilities. The disease does not result in systemic illness, infertility or abortion, yet it does have a negative impact on the equine industry as it forc...
Gordon J, Álvarez-Narváez S, Peroni JF.The development of antimicrobial resistant bacteria and the lack of novel antibiotic strategies to combat those bacteria is an ever-present problem in both veterinary and human medicine. The goal of this study is to evaluate platelet lysate (PL) as a biological alternative antimicrobial product. Platelet lysate is an acellular platelet-derived product rich in growth factors and cytokines that is manufactured via plateletpheresis and pooled from donor horses. In the current study, we sought to define the antimicrobial properties of PL on select gram-positive and gram-negative bacteria. Results ...
Jelocnik M, Nyari S, Anstey S, Playford N, Fraser TA, Mitchell K, Blishen A, Pollak NM, Carrick J, Chicken C, Jenkins C.C. psittaci has recently emerged as an equine abortigenic pathogen causing significant losses to the Australian Thoroughbred industry, while Equine herpesvirus-1 (EHV-1) is a well-recognized abortigenic agent. Diagnosis of these agents is based on molecular assays in diagnostic laboratories. In this study, we validated C. psittaci and newly developed EHV-1 Loop Mediated Isothermal Amplification (LAMP) assays performed in a real-time fluorometer (rtLAMP) against the reference diagnostic assays. We also evaluated isothermal amplification using commercially available colorimetric mix (cLAMP), and...
Kulikov EE, Golomidova AK, Efimov AD, Belalov IS, Letarova MA, Zdorovenko EL, Knirel YA, Dmitrenok AS, Letarov AV.Tailed bacteriophages constitute the bulk of the intestinal viromes of vertebrate animals. However, the relationships between lytic and lysogenic lifestyles of phages in these ecosystems are not always clear and may vary between the species or even between the individuals. The human intestinal (fecal) viromes are dominated mostly by temperate phages, while in horse feces virulent phages are more prevalent. To our knowledge, all the previously reported isolates of horse fecal coliphages are virulent. Temperate coliphage Hf4s was isolated from horse feces, from the indigenous equine Escherichia ...
Palozzo A, Traversa D, Marruchella G, Celani G, Morelli S, Petrizzi L.Cutaneous habronemosis in horses is caused by larvae of the spirurid nematodes Habronema microstoma and Habronema muscae. These lesions, also known as "summer sores'', are often severe and disfiguring. Although Habronema-caused lesions at the coronary grooves have been described, cases of hoof cracks with secondary summer sores have never been reported. The present case describes clinic-pathological and surgical features of a quarter crack case complicated by cutaneous habronemosis at the dermal layers. A 15-year-old, Andalusian stallion was referred to the Veterinary Teaching Hospital of the ...
Sundstrom KD, Lineberry MW, Grant AN, Duncan KT, Ientile MM, Little SE.Ticks are common on horses, but recent publications characterizing equine tick infestations in North America are lacking. Methods: To further understand attachment site preferences of common ticks of horses, and to document the seasonality of equine tick infestation in northeastern Oklahoma, horses from eight farms were evaluated twice a month over a 1-year period. Each horse was systematically inspected beginning at the head and moving caudally to the tail. Attachment sites of ticks were recorded and all ticks collected were identified to species and stage. Results: Horses (26 males and 62 fe...
Altan E, Hui A, Li Y, Pesavento P, Asín J, Crossley B, Deng X, Uzal FA, Delwart E.Six foals with interstitial pneumonia of undetermined etiology from Southern California were analyzed by viral metagenomics. Spleen, lung, and colon content samples obtained during necropsy from each animal were pooled, and nucleic acids from virus-like particles enriched for deep sequencing. The recently described equine copiparvovirus named eqcopivirus, as well as three previously uncharacterized viruses, were identified. The complete ORFs genomes of two closely related protoparvoviruses, and of a bocaparvovirus, plus the partial genome of a picornavirus were assembled. The parvoviruses were...
Kopper JJ, Willette JA, Kogan CJ, Seguin A, Bolin SR, Schott HC.Rates of detecting ≥1 potential enteric pathogens (PEP) or toxins (PEP-T) in feces, blood, or both of horses ≥6 months of age with enteric disease and impact of multiple detections on outcome of horses with colitis has not been reported. Objective: To determine detection rates of PEP/PEP-T in feces, blood, or both of horses with enteric disease and effect of detecting multiple agents on outcome of horses with colitis. Methods: Thirty-seven hundred fifty-three fecal samples submitted to IDEXX Laboratories and 239 fecal and blood samples submitted to Michigan State University's Veterinary D...
Zehetner V, Cavalleri JV, Klang A, Hofer M, Preining I, Steinborn R, Ramsauer AS.There is strong evidence that equine parvovirus-hepatitis (EqPV-H) is associated with the onset of Theiler's disease, an acute hepatic necrosis, in horses. However, the impact of this virus on other hepatopathies remains unknown. The objective of this retrospective study was to evaluate the prevalence and quantify the viral loads of EqPV-H in formalin-fixed, paraffin-embedded equine and donkey livers with various histopathologic abnormalities. The pathologies included cirrhosis, circulatory disorders of the liver, toxic and metabolic hepatic diseases as well as neoplastic and inflammatory dise...
Huang H, Zhang K, Zhang B, Liu S, Chu H, Qi Y, Zhang D, Li K.Gasterophilus spp. have been found to be widespread in reintroduced Przewalski's horses in the Kalamaili Nature Reserve (Northwest China). However, data on the annual variation in Gasterophilus infections are lacking. To analyze the epidemiological features and determine the cause of the annual variation in Gasterophilus infections, we treated 110 Przewalski's horses with ivermectin and collected Gasterophilus larvae from fecal samples each winter from 2007 to 2019. All 110 Przewalski's horses studied were found to be infected by Gasterophilus spp., and a total of 141 379 larvae were collected...
Ghafar A, Abbas G, King J, Jacobson C, Hughes KJ, El-Hage C, Beasley A, Bauquier J, Wilkes EJA, Hurley J, Cudmore L, Carrigan P, Tennent-Brown B....Faecal egg counting techniques (FECT) form the cornerstone for the detection of gastrointestinal parasites in equines. For this purpose, several flotation, centrifugation, image- and artificial intelligence-based techniques are used, with varying levels of performance. This review aimed to critically appraise the literature on the assessment and comparison of various coprological techniques and/or modifications of these techniques used for equines and to identify the knowledge gaps and future research directions. We searched three databases for published scientific studies on the assessment an...
von Samson-Himmelstjerna G, Janssen IJI, Ramünke S, Goday C, Borges FA, Koudela B, Niedźwiedź A, Tomczuk K, Studzińska MB, Kornas S, Krücken J.Equines were over decades considered to be infected by two morphologically virtually indistinguishable ascarid species, Parascaris univalens and Parascaris equorum. Reliable species discrimination is only possible using enzyme isoelectric focussing and karyotyping with P. univalens having one and P. equorum two chromosome pairs. However, presumably the complexity of both methods prevented their routine use in nearly all previous studies about prevalence and drug resistance of Parascaris spp. These have barely been performed on the species level although most studies stated presence of one or t...
Staji H, Yousefi M, Hamedani MA, Tamai IA, Khaligh SG.Anaplasma spp. are among the most recognized arthropod-borne infectious agents. Although the novel A. capra has been isolated from wildlife, livestock, and hard ticks from many parts of the world, there is no report regarding the identification of this pathogen from equines and little is known about the epidemiology of A. capra in Equidae. In this study, A. capra was identified in two out of ten blood specimens of wild onagers (Equus hemionus onager) during a routine health check-up in Semnan, Iran by light microscopy and molecular analyses while other pathogens were not detected. First, inclu...
Jota Baptista C, Sós E, Szabados T, Kerekes V, Madeira de Carvalho L.The Pentezug Wildhorse Reserve, located in the Hortobágy National Park, Hungary, has one of the biggest ex situ populations of Przewalski's horses and aims to preserve its landscape and to study this subspecies. Between September and November 2018, 79 faecal samples were collected from Przewalski's horses. The McMaster, Willis flotation, natural sedimentation and coproculture methods were applied to all the samples. Results showed an average level of 1287 eggs per gram (EPG), which is a high faecal egg-shedding level. All the samples were positive for strongyle-type eggs (100%). There were no...
Alsing-Johansson T, Pedersen A, Bergström K, Sternberg-Lewerin S, Penell J, Bergh A.Equine dentistry has developed immensely and human dental equipment, such as handpieces, are often used. Measures to avoid the spread of infectious microorganisms are important, but this is challenging since handpieces are difficult to decontaminate. Thus, it is necessary to develop effective IPC measures in equine dentistry. The aim of this study was to contribute to the evidence needed for future evidence-based guidelines on IPC by investigating hygiene in equine dentistry. Used handpieces and dummies (i.e., handpieces not used during dental procedure, reflecting environmental bacterial cont...
Merchán A, Voss JK, Dubois MS.The satisfactory outcome of fungal osteitis in an 8-year-old American Quarter Horse is described. The horse was admitted with a grade 4 out of 5 lameness and exhibited metacarpophalangeal synovial effusion, indicative of a mild suppurative inflammation. Results of initial radiographic and ultrasonographic examination were unremarkable. Intra-articular anesthesia of the metacarpophalangeal joint allowed localization of the insult. It was not until day 6 of hospitalization when lytic changes on the axial aspect were observed on radiographic examination. Arthroscopic examination permitted identif...
Ortega-García MV, Salguero FJ, García N, Domínguez M, Moreno I, Berrocal A.Cutaneous forms of leishmaniosis due to Leishmania braziliensis have been reported in horses in the New World. Domestic animals play a role in the transmission of the disease. In Costa Rica, human cases of L. braziliensis, L. panamensis and L. infantum have been reported. The present report describes five cases of equine cutaneous leishmaniosis in Costa Rica. The aetiological diagnosis was based on the presence of the parasite within the lesions. Skin biopsies were used to perform histopathological analyses of the lesions. Immunohistochemistry was used to detect the presence of the Leishmania ...
Zhou R, Yang J, Zhang K, Qi Y, Ma W, Wang Z, Ente M, Li K.The absolute dominant species that infests wild population of Przewalski's horse (Equus przewalskii) is Gasterophilus pecorum, and feces of released Przewalski's horse, a habitat odor, plays an important role in mating and ovipositing locations of G. pecorum. To screen out unique volatiles for attracting G. pecorum, volatiles from fresh feces of released horses at stages of pre-oviposition (PREO), oviposition (OVIP), and post-oviposition (POSO) of G. pecorum, and feces with three different freshness states (i.e., Fresh, Semi-fresh, and Dry) at OVIP were collected by dynamic headspace adsorptio...
Bażanów B, Pawęska JT, Pogorzelska A, Florek M, Frącka A, Gębarowski T, Chwirot W, Stygar D.Huculs () are an old breed of primitive mountain horses, originating from the Carpathian Mountains. To the best of our knowledge, data concerning the epidemiology of viral infections observed within this breed are sparse. The objective of this study was to estimate the serological status of a semi-isolated, unvaccinated Hucul herd, with respect to both common equine viral infections and horse-infecting arboviruses, the presence of which was previously reported in Poland. Twenty horses of the Hucul breed, living in a remote area in Poland, were studied in 2018 from March to May. Using nasal sec...
Geurden T, De Keersmaecker F, De Keersmaecker S, Claerebout E, Leathwick DM, Nielsen MK, Sauermann CW.In the present study, an anthelmintic treatment regimen with reduced treatment frequency was evaluated in horses on two study sites in Belgium during three consecutive summer pasture seasons. Historically, the horses on both study sites were treated up to 6 times a year with ivermectin (IVM) or up to 4 times a year with moxidectin (MOX), and previous efficacy evaluations indicated a reduced egg reappearance period in some of the treated horses for both IVM (28 days) and MOX (42 days). In the present study, all horses were treated with IVM or MOX in the spring and in autumn. Faecal egg counts (...
Haspeslagh M, Van Hecke LL, Hermans K, Chiers K, Pint E, Wilmink JM, Martens AM.Distal limb wounds in horses often show aberrant healing due to a slow inflammatory response. In human medicine, negative pressure wound therapy (NPWT) is used for the treatment of chronic wounds with a similar inflammatory response. Objective: To compare the effect of NPWT to calcium alginate dressings on the healing of (non) contaminated equine distal limb wounds. Methods: Controlled experiment. Methods: Circular wounds were created on the left and right dorsomedial metacarpus of 10 horses. In five horses, the wounds were contaminated with Staphylococcus aureus and Pseudomonas aeruginosa. In...
Cohen ND, Kahn SK, Cywes-Bentley C, Ramirez-Cortez S, Schuckert AE, Vinacur M, Bordin AI, Pier GB.Rhodococcus equi is a prevalent cause of pneumonia in foals worldwide. Our laboratory has demonstrated that vaccination against the surface polysaccharide β-1→6-poly-N-acetylglucosamine (PNAG) protects foals against intrabronchial infection with R. equi when challenged at age 28 days. However, it is important that the efficacy of this vaccine be evaluated in foals when they are infected at an earlier age, because foals are naturally exposed to virulent R. equi in their environment from birth and because susceptibility is inversely related to age in foals. Using a randomized, blind experim...
Erol E, Scortti M, Fortner J, Patel M, Vázquez-Boland JA.Clonal multidrug resistance recently emerged in Rhodococcus equi, complicating the therapeutic management of this difficult-to-treat animal- and human-pathogenic actinomycete. The currently spreading multidrug-resistant (MDR) "2287" clone arose in equine farms upon acquisition, and coselection by mass macrolide-rifampin therapy, of the pRErm46 plasmid carrying the (46) macrolide-lincosamide-streptogramin resistance determinant, and of an mutation. Here, we screened a collection of susceptible and macrolide-resistant strains from equine clinical cases using a panel of 15 antimicrobials agains...
Ellero N, Lanci A, Avallone G, Mariella J, Castagnetti C, Muscatello LV, Di Maio C, Freccero F.Seizures, coma and death rapidly appeared after admission in a one ‑month‑old foal with a history of lethargy, fever and anorexia. Severe icterus and necrotizing hepatitis were observed at necropsy. Clinical signs, laboratory and postmortem findings were compatible with a suspect of clostridial hepatitis. Tyzzer’s disease was confirmed by the presence of organisms morphologically consistent with Clostridium piliforme in the hepatocytes at the margins of multiple areas of hepatic necrosis. To the authors’ knowledge, this is the first reported case of clostridial hepatitis caused by Clos...
Reinecke B, Klöhn M, Brüggemann Y, Kinast V, Todt D, Stang A, Badenhorst M, Koeppel K, Guthrie A, Groner U, Puff C, de le Roi M, Baumgärtner W....Since its first discovery by Arnold Theiler in 1918, serum hepatitis also known as Theiler's disease has been reported worldwide, causing idiopathic acute hepatitis and liver failure in horses. Recent studies have suggested a novel parvovirus, named equine parvovirus hepatitis (EqPV-H), to be associated with Theiler's disease. Despite the severity and potential fatality of EqPV-H infection, little is known about the possibility of developing chronic infections and putative cross-species infection of equine sister species. In the present longitudinal study, we employed qPCR analysis, serology, ...
von Samson-Himmelstjerna G, Thompson RA, Krücken J, Grant W, Bowman DD, Schnyder M, Deplazes P.Anthelmintic resistance (AR) has thus far only rarely been reported for intestinal helminths of dogs and cats, in contrast to parasites of livestock and horses. We highlight possible reasons for this striking and important discrepancy, including ecological, biological and genetic factors and/or intervention regimens of key intestinal helminths concerning both host groups. In view of the current knowledge related to the genetics, mechanisms and principles of AR development, we point at issues which in our view contribute to a comparatively lower risk of AR development in intestinal helminths of...
Martin F, Eydal M, Höglund J, Tydén E.The equine roundworm Parascaris univalens has developed resistance to the three anthelmintic substances most commonly used in horses. The mechanisms responsible for resistance are believed to be multi-genic, and transport proteins such as the P-glycoprotein (Pgp) family have been suggested to be involved in resistance in several parasites including P. univlaens. To facilitate further research into the mechanisms behind drug metabolism and resistance development in P. univalens we aimed to develop an in vitro model based on larvae. We developed a fast and easy protocol for hatching P. univalens...
Vandenberghe E, Boshuizen B, Delesalle CJG, Goehring LS, Groome KA, van Maanen K, de Bruijn CM.In May 2018, Wolvega Equine Hospital (WEH) experienced an EHV-1 outbreak. This outbreak caused significant economic losses and negative publicity for the hospital. How should hospitals prepare themselves for these outbreaks and prevent shedding of the virus on multiple neighboring premises? The hospital transformed most of its activities into mobile practice and the entire infected hospital population was moved to a separate remote location. The hospital was cleaned and disinfected according to the latest recommendations before reopening. Four neighboring professional equine businesses and thr...
Negash W, Erdachew Y, Dubie T.In Ethiopia, equines serve in traction power, carting, recreation, festival packing, riding, transportation, and other activities since time immemorial. Strongyles are common equine health problems in Ethiopia though research based data on equine strongyles are limited particularly in the study areas, in and around Mekelle city. Therefore, the present study was intended to estimate the prevalence of common equine strongyles in and around Mekelle city from November 2018 to April 2019 and to assess risk factors associated with infection of strongyle parasites as well. Cross sectional design was ...
Ambagala APN, Gopinath RS, Srikumaran S.Equine herpesvirus-1 (EHV-1) downregulates surface expression of major histocompatibility complex (MHC) class I molecules on infected cells. The objective of this study was to investigate whether EHV-1 interferes with peptide translocation by the transporter associated with antigen processing (TAP) and to identify the proteins responsible. Using an in vitro transport assay, we showed that EHV-1 inhibited transport of peptides by TAP as early as 2 h post-infection (p.i). Complete shutdown of peptide transport was observed by 8 h p.i. Furthermore, pulse-chase experiments revealed that maturation...
Christoffersen M, Woodward EM, Bojesen AM, Petersen MR, Squires EL, Lehn-Jensen H, Troedsson MH.The objective of the present study was to evaluate the effect of immunomodulatory therapy (glucocorticoids (GC) and mycobacterium cell wall extract (MCWE)) on the endometrial gene expression of inflammatory cytokines in susceptible mares with induced infectious endometritis. Endometrial gene expression of pro- and anti-inflammatory cytokines; interleukin (IL)-1β, IL-6, IL-8, IL-10, tumor necrosis factor (TNF)-α, IL-1 receptor antagonist (ra), acute phase protein (APP) serum amyloid A (SAA) and clinical parameters were evaluated. Five mares were classified as susceptible to persistent endomet...
Abbott Y, Leggett B, Rossney AS, Leonard FC, Markey BK.A retrospective analysis and prospective surveillance study were conducted to determine isolation rates of meticillin-resistant Staphylococcus aureus (MRSA) in dogs, cats and horses in Ireland. Clinical samples that had been submitted to University College Dublin (UCD) for routine microbiological examination over a four-year period (2003 to 2006) were analysed in the retrospective analysis, which included clinical samples from 3866 animals. In the prospective surveillance study, samples from healthy animals presenting for elective surgery as well as from animals with a clinical presentation su...
Smith DR, Schmaljohn CS, Badger C, Ostrowski K, Zeng X, Grimes SD, Rayner JO.Venezuelan, eastern, and western equine encephalitis viruses (VEEV, EEEV, and WEEV) are mosquito-borne viruses in the Americas that cause central nervous system (CNS) disease in humans and equids. In this study, we directly characterized the pathogenesis of VEEV, EEEV, and WEEV in cynomolgus macaques following subcutaneous exposure because this route more closely mimics natural infection via mosquito transmission or by an accidental needle stick. Our results highlight how EEEV is significantly more pathogenic compared to VEEV similarly to what is observed in humans. Interestingly, EEEV appears...
Lange CE, Tobler K, Lehner A, Grest P, Welle MM, Schwarzwald CC, Favrot C.Equine penile papillomas, in situ carcinomas, and invasive carcinomas are hypothesized to belong to a continuum of papillomavirus-induced diseases. The former ones clinically present as small grey papules, while the latter 2 lesions are more hyperplasic or alternatively ulcerated. To test the hypothesis that these lesions are papillomavirus-induced, samples of 24 horses with characteristic clinical and histologic findings of penile papillomas or in situ or invasive squamous cell carcinomas were collected. As controls, 11 horses with various lesions--namely, Balanoposthitis (6 cases), melanoma ...
Contreras M, Morales A, García-Amado MA, De Vera M, Bermúdez V, Gueneau P.To assess the presence of Helicobacter DNA in the gastric mucosa Thoroughbred horses. Results: Squamous and glandular mucosa samples were collected from 20 Thoroughbreds. None of these horses had shown any clinical symptoms of gastrointestinal disease. Necropsy tissues were analysed using histopathological techniques and a Helicobacter genus-specific PCR assay followed by sequencing of the amplicons. Seven horses were diagnosed with gastric ulceration, five with gastritis and six with both pathologies. Only two horses had a healthy gastric mucosa. Helicobacter-like DNA was detected in two out ...
Apt W, Aguilera X, Vega F, Alcaíno H, Zulantay I, Apt P, González V, Retamal C, Rodríguez J, Sandoval J.This study sought to estimate for the first time the prevalence of fascioliasis among the rural population in the Chilean provinces of Curico, Talca, and Linares, while also determining the disease's prevalence among horses and wild rabbits in Curico and Talca and among pigs in Talca. From January 1986 to December 1990 a randomly selected sample of 5,861 persons in the three provinces was given intradermal, complement-fixation, double-diffusion, and immunoelectrophoresis tests to detect antibody to Fasciola hepatica. In addition, the ELISA test was used in Talca and Linares. Fecal specimens fr...
Xiao L, Herd RP.Prevalence and infection patterns of Cryptosporidium and Giardia infections in horses were studied by a direct immunofluorescence staining method. Faecal examinations of 222 horses of different age groups revealed Cryptosporidium infection rates of 15-31% in 66 foals surveyed in central Ohio, southern Ohio and central Kentucky, USA. Only 1 of 39 weanlings, 0 of 46 yearlings, and 0 of 71 mares were positive. Giardia infection was found in all age groups, although the infection rates for foals were higher (17-35%). Chronological study of infection in 35 foals showed that foals started to excrete...
Detournay O, Morrison DA, Wagner B, Zarnegar B, Wattrang E.This study aimed at identifying all of the type I interferon (IFN) genes of the horse and at monitoring their expression in equine cells on in vitro induction. We identified 32 putative type I IFN loci on horse chromosome 23 and an unplaced genomic scaffold. A phylogentic analysis characterized these into 8 different type I IFN classes, that is, putative functional genes for 6 IFN-α, 4 IFN-β, 8 IFN-ω (plus 4 pseudogenes), 3 IFN-δ (plus 1 pseudogene), 1 IFN-κ and 1 IFN-ε, plus 1 IFN-ν pseudogene, and 3 loci belonging to what has previously been called IFN-αω. Our analyses indicate that...
Gustchina A, Kervinen J, Powell DJ, Zdanov A, Kay J, Wlodawer A.Equine infectious anemia virus (EIAV), the causative agent of infectious anemia in horses, is a member of the lentiviral family. The virus-encoded proteinase (PR) processes viral polyproteins into functional molecules during replication and it also cleaves viral nucleocapsid protein during infection. The X-ray structure of a complex of the 154G mutant of EIAV PR with the inhibitor HBY-793 was solved at 1.8 A resolution and refined to a crystallographic R-factor of 0.136. The molecule is a dimer in which the monomers are related by a crystallographic twofold axis. Although both the enzyme and t...
Klei TR, Chapman MR.Defining the characteristics of immunity and immune responses to equine cyathostome infections is clearly important to advancing our understanding of the development of these nematodes within the host, the clinical conditions attributed to them, and in developing more rational and novel strategies for their control. Nonetheless, little is currently known on this topic. Current data based on field observations, worm burdens and fecal egg counts suggest that horses acquire a resistance to cyathostome infection with age. This response is slow to develop and incomplete in that most horses regardle...
Youn HJ, Lakritz J, Kim DY, Rottinghaus GE, Marsh AE.The purpose of this study was to determine whether alcohol extracts of herbs (Sophora flavescens Aiton, Sinomenium acutum (Thunb.) Rehder and E.H. Wilson, Pulsatilla koreana (Yabe ex Nakai) Nakai ex T. Mori, Ulmus macrocarpa Hance and Torilis japonica (Houtt.) DC.) from South Korea, possess in vitro anti-protozoal activity against cultures of Toxoplasma gondii and Neospora caninum. These herbs have been used as human anti-parasitics in Asian countries for many years. Alcohol extracts of these herbs were serially diluted to final concentrations ranging from 625 to 19.5 ng/ml in media and added ...
Snijder EJ, Ederveen J, Spaan WJ, Weiss M, Horzinek MC.From 380S particles of Berne virus (proposed family Toroviridae) one species of polyadenylated RNA was isolated. Using agarose gel electrophoresis its length was estimated as 20 kb or greater. When assayed under hypertonic transfection conditions genomic RNA was found to be infectious; RNase treatment destroyed the infectivity. The positive polarity of the molecule was confirmed by filter spot hybridization using cDNA prepared against poly(A)-selected RNA from infected cells. In embryonic mule skin cells infected with Berne virus the presence of five virus-specific, polyadenylated RNA species ...
Wieringa R, De Vries AA, Post SM, Rottier PJ.Equine arteritis virus (EAV) is an enveloped, positive-strand RNA virus belonging to the family Arteriviridae of the order NIDOVIRALES: EAV virions contain six different envelope proteins. The glycoprotein GP(5) (previously named G(L)) and the unglycosylated membrane protein M are the major envelope proteins, while the glycoproteins GP(2b) (previously named G(S)), GP(3), and GP(4) are minor structural proteins. The unglycosylated small hydrophobic envelope protein E is present in virus particles in intermediate molar amounts compared to the other transmembrane proteins. The GP(5) and M protein...
Tonkin DR, Whitmore A, Johnston RE, Barro M.Replicon particles derived from Venezuelan equine encephalitis virus (VEE) are infectious non-propagating particles which act as a safe and potent systemic, mucosal, and cellular adjuvant when delivered with antigen. VEE and VEE replicon particles (VRP) can target multiple cell types including dendritic cells (DCs). The role of these cell types in VRP adjuvant activity has not been previously evaluated, and for these studies we focused on the contribution of DCs to the response to VRP. By analysis of VRP targeting in the draining lymph node, we found that VRP induced rapid recruitment of TNF-s...
Linde HJ, Kobuch R, Jayasinghe S, Reischl U, Lehn N, Kaulfuss S, Beutin L.We report the first case of a postoperative wound infection caused by Vibrio metschnikovii on the lower right leg of a patient after saphenectomy. Compared to the healing of an uninfected site, that of the right leg was delayed, and a cure was achieved by intensified wound care. Several swabs taken from the infected site grew a gram-negative rod in pure culture that was identified as V. metschnikovii by the VITEK 2 system. The source of the infection was not detected; however, the absence of putative risk factors (exposure to water or shellfish or an episode of diarrhea), the profession of the...
Brum MC, Anjos BL, Nogueira CE, Amaral LA, Weiblen R, Flores EF.An outbreak of severe cutaneous disease associated with an orthopoxvirus in horses in southern Brazil is described. Fourteen Crioulo mares and foals from a husbandry farm developed papules, and vesicles progressing to proliferative and exudative lesions on the muzzle, external nares, and external and internal lips. The vesicles eroded, and the proliferative lesions eventually bled and progressed to moist crusts and scars. The clinical signs lasted approximately 6-12 days, after which the animals progressively recovered. Direct electron microscopy of skin biopsies revealed brick-shaped, 250-300...
Uzal FA, Diab SS, Blanchard P, Moore J, Anthenill L, Shahriar F, Garcia JP, Songer JG.Clostridium perfringens type C is one of the most important agents of enteric disease in newborn foals. Clostridium difficile is now recognized as an important cause of enterocolitis in horses of all ages. While infections by C. perfringens type C or C. difficile are frequently seen, we are not aware of any report describing combined infection by these two microorganisms in foals. We present here five cases of foal enterocolitis associated with C. difficile and C. perfringens type C infection. Five foals between one and seven days of age were submitted for necropsy examination to the Californi...
Wong DM, Wilkins PA.Defining and describing the systemic inflammatory response syndrome (SIRS) and sepsis facilitated recognition and investigation of the complex disease processes involving the host response to infection and trauma. Over the years a variety of definitions of SIRS have been examined and applied to numerous research studies to improve critical care in both human and veterinary clinical practice. This article summarizes the history of the development of the SIRS definition, outlines the pathophysiologic processes that are involved in SIRS, and provides a specific definition for use in foal medicine...
Del Piero F.Equine viral arteritis (EVA) can cause prominent economic losses for the equine industry. The purpose of this review is to provide the pathologist some familiarity with the clinical history, lesions, pathogenesis, and diagnosis of EVA. EVA is caused by an arterivirus (equine arteritis virus, EAV), and the vascular system is the principal but not unique viral target. EVA has variable presentations, including interstitial pneumonia, panvasculitis with edema, thrombosis and hemorrhage, lymphoid necrosis, renal tubular necrosis, abortion, and inflammation of male accessory genital glands. EAV anti...
Pusterla N, Leutenegger CM, Wilson WD, Watson JL, Ferraro GL, Madigan JE.Based on the hypothesis that the viral load of cells infected with EHV-4 will likely change during the course of disease, TaqMan PCR was used to investigate and characterize the kinetics of EHV-4 viral DNA load (glycoprotein B gene) and transcriptional activity (glycoprotein B and latency-associated transcripts) in peripheral blood leukocytes (PBLs) and nasopharyngeal secretions (NSs) collected from 11 foals during a field outbreak of respiratory disease. The EHV-4 DNA load in PBLs was low and of short duration after onset of clinical signs. In contrast, the EHV-4 load in NSs remained high for...
van Spijk JN, Schmitt S, Fürst AE, Schoster A.Antimicrobial resistance has become an important concern in veterinary medicine. The aim of this study was to describe the rate of antimicrobial resistance in common equine pathogens and to determine the occurrence of multidrug-resistant isolates. A retrospective analysis of all susceptibility testing results from bacterial pathogens cultured from horses at the University of Zurich Equine Hospital (2012-2015) was performed. Strains exhibiting resistance to 3 or more antimicrobial categories were defined as multidrug-resistant. Susceptibility results from 303 bacterial pathogens were analyzed, ...
Healey K, Lawlor C, Knox MR, Chambers M, Lamb J, Groves P.A series of placebo-controlled trials were conducted in horses, cattle and goats in different seasons and bioclimatic regions of New South Wales and Queensland, Australia, to evaluate the ability of BioWorma®, a feed supplement containing the spores of Duddingtonia flagrans IAH 1297, to reduce the larval development of parasitic gastrointestinal nematodes (GIN) and their subsequent migration from faeces onto the surrounding pasture. In each trial, faeces were collected from animals harbouring a burden of nematode parasites following a period of supplementation with a placebo and again after s...
Hurley JR, Begg AP.A trial was conducted on a Thoroughbred stud to determine whether or not the administration of anti-Rhodococcus equi hyperimmune plasma would reduce the prevalence of R equi pneumonia (rattles) in foals born in the 1992 horse breeding season. Hyperimmune plasma was administered to 34 foals; another 57 foals were untreated. There was no significant difference in the number of transfused foals developing R equi pneumonia compared with the untreated foals. The time required for recovery from pneumonia between the 2 groups was not significantly different.
Perryman LE, McGuire TC, Crawford TB.Sixty-six cases of combined immunodeficiency (CID) in foals were studied to determine the most prevalent causes of infection and death. Lesions of the respiratory system were observed in 59 of the foals and were attributable to infection with equine adenovirus. Pneumocystis carinii, and bacteria. Significant lesions were also observed in liver, pancreas, intestines, heart, and kidneys. Maintenance of foals with CID for experimental purposes is directed at the prevention and control of these secondary infections. Adenovirus can be controlled by administration of horse plasma containing high tit...
Corley KT, Pearce G, Magdesian KG, Wilson WD.Treatment for bacteraemia in foals must be started before the identity of the causative organism is known. Information aiding selection of effective antimicrobials should improve outcome. Objective: To describe differences in clinical and clinicopathological data and outcome in foals with bacteraemia due to different classes of bacteria. Methods: Records of foals with a positive blood culture, age < 10 days and presenting to a university hospital 1995-2004, were reviewed. Bacterial culture results, subject details, historical information, physical examination findings at admission and clini...
Guthrie AJ, Howell PG, Gardner IA, Swanepoel RE, Nurton JP, Harper CK, Pardini A, Groenewald D, Visage CW, Hedges JF, Balasuriya UB, Cornel AJ....West Nile virus (WNV) infection is endemic in southern Africa. With the recent emergence of WNV infection of horses in Europe and the USA the present study was performed to estimate the risk of seroconversion to WNV in a cohort of 488 young Thoroughbred (TB) horses. Objective: To estimate the risk of seroconversion to WNV among a cohort of South African TB yearlings sold at the 2001 National Yearling Sales (NYS) and to determine whether the risk varied geographically. Two horses were also infected with a recent South African isolate of WNV to evaluate its virulence in horses. Methods: Serum sa...
