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.
Li S, Li L, Sun Y, Khan MZ, Yu Y, Ruan L, Chen L, Zhao J, Jia J, Li Y, Wang C, Wang T.Equid herpesvirus type 8 (EqHV-8) is known to cause respiratory disease and miscarriage in horses and donkeys, which is a major problem for the equine farming industry. However, there are currently limited vaccines or drugs available to effectively treat EqHV-8 infection. Therefore, it is crucial to develop new antiviral approaches to prevent potential pandemics caused by EqHV-8. This study evaluates the antiviral and antioxidant effects of cepharanthine against EqHV-8 by employing both in vitro assays and in vivo mouse models to assess its therapeutic efficacy. To assess the effectiveness of ...
Cheong SH, Franklin-Guild R, Goodman LB, Lago-Alvarez Y, Lee YL, de Aguiar LH, de Amorim MD, Altier C.Fungal and bacterial culture is currently the primary method for pathogen detection and identification. Next-generation sequencing is a powerful method for detecting and identifying the presence of microbial DNA in samples. We evaluated the correlation between fungal and bacterial culture with next-generation sequencing in equine uterine samples. Fungal cultures (n=63) were evaluated based on their culture results. In culture positive (n=16) samples, next-generation sequencing identified the same organism in 10 samples (62.5%), 5 samples did not identify fungal agents, and 1 sample identified ...
Toft K, Honoré ML, Ripley NE, Nielsen MK, Fromm B, Mardahl M, Nielsen LN, Nejsum P, Thamsborg SM, Cirera S, Pihl TH.The equine bloodworm, Strongylus vulgaris, is a highly pathogenic parasite causing potentially fatal vascular and intestinal damage. Parasites express and release microRNAs (miRNAs) for internal regulation and to modulate host immunity. The complete set of miRNAs expressed by S. vulgaris (the S. vulgaris miRNAome) remains unannotated and the aim of this study was to annotate the miRNAome of L4 and L5 stages of S. vulgaris, and to examine differences in miRNA abundance between larval stages and sexes. Furthermore, we aimed to determine if miRNAs were detectable in excretory/secretory products (...
Phetkarl T, Fungwithaya P, Lewchalermvong K, Sontigun N.The global prevalence of gastrointestinal (GI) and blood parasite infections in horses is a significant concern due to their substantial impact on morbidity, mortality, and economic losses in the horse industry. In Thailand, limited research has been conducted on these parasites in horse populations, and data from southern Thailand are lacking. Consequently, this study aimed to estimate the prevalence of GI and blood parasites in horses in Nakhon Si Thammarat province, Thailand. Unassigned: In total, 79 fecal and blood samples were collected from horses across 11 farms in Nakhon Si Thammarat p...
Yuen NKY, Harrison JJ, Wang ASW, McMahon IE, Habarugira G, Coyle MP, Bielefeldt-Ohmann H.An incursion and outbreak of Japanese encephalitis virus (JEV) was reported in Australia in 2021 and 2022, respectively. There was speculation that JEV may have been circulating in Australia unknowingly prior to the detection. In this study, we determined sero-prevalence and transmission of West Nile virus (WNV), Murray Valley encephalitis virus (MVEV) and JEV, prior to and post JEV incursion in a sentinel equine population in south-east Queensland (SEQ), Australia, using blocking ELISAs (screening test) and virus neutralisation test (confirmatory). Serum samples collected between 2018 and 202...
Ryu SH, Jang B, Kim BS, Park KT.This is the first report describing the isolation and genome sequence of Flavobacterium ceti (F. ceti IJFC025) from a draining submandibular lymph node abscess in a 6-year-old mixed-breed mare in Korea. Since F. ceti is not a usual infectious pathogen that causes equine health problems, this study presents the complete genome sequence of F. ceti isolated from a submandibular lymph node abscess sample in Jeju, South Korea, in 2022. The entire genome sequence of F. ceti IJFC025 consisted of a 3,144,426-bp chromosome with 35.6 % G + C content. Gene prediction revealed that this strain possesse...
Khatibzadeh SM, Dahlgren LA, Caswell CC, Ducker WA, Werre SR, Bogers SH.Biofilms reduce antibiotic efficacy and lead to complications and mortality in human and equine patients with orthopedic infections. Equine bone marrow-derived mesenchymal stromal cells (MSC) kill planktonic bacteria and prevent biofilm formation, but their ability to disrupt established orthopedic biofilms is unknown. Our objective was to evaluate the ability of MSC to reduce established S. aureus or E. coli biofilms in vitro. We hypothesized that MSC would reduce biofilm matrix and colony-forming units (CFU) compared to no treatment and that MSC combined with the antibiotic, amikacin sulfate...
Köhne M, Hüsch R, Tönissen A, Schmidt M, Müsken M, Böttcher D, Hirnet J, Plötz M, Kittler S, Sieme H. subspecies (subsp.) is an important facultative pathogen in horses and can cause severe infections in other species including humans. Facing the post-antibiotic era, novel antimicrobials are needed for fighting bacterial infections. Bacteriophages (phages) are the natural predators of bacteria and discussed as a promising antimicrobial treatment option. The objective of this study was to isolate and characterize subsp. specific phages for the first time and to evaluate their efficacy and . In total, 13 phages with lytic activity were isolated and host ranges were determined. Two phages wit...
Tasnim Y, Stanley C, Rahman MK, Awosile B.We aim to detect beta-lactamase-producing Citrobacter sedlakii from horses and compare the genomic characteristics with isolates from humans. Results: We characterized phenotypically and genotypically nine C. sedlakii isolates from the feces of horses and then compared them to human-derived isolates using whole genome sequencing and phylogenomic methods. Seven isolates (7/9) were ampicillin-resistant, while at least one isolate was resistant to ceftriaxone, gentamicin, meropenem, and streptomycin. All nine isolates were carriers of the chromosomal-mediated blaSED-1 beta-lactamase gene, which...
Loomes K, de Grauw J, Gozalo-Marcilla M, Redondo JI, Bettschart-Wolfensberger R.Equine post-operative morbidity represents a significant concern for both veterinary surgeons and horse owners. Objective: To estimate the prevalence of post-operative complications in horses after elective/non-abdominal surgery or colic surgery. Methods: Systematic review. Methods: A database search identified eligible studies which reported the prevalence of equine post-operative complications published as a full paper in English in a peer-reviewed journal between 2000 and 2023. Studies were evaluated using the JBI Critical Appraisal Checklist for Prevalence Studies and GRADE (Grading of Rec...
Smith HL, Love KR, Antezana A, Barr EM, Gilger BC, Oh A.To determine clinical outcome, treatment costs, and hospitalization duration in horses treated for keratomycosis and identify ophthalmic examination and diagnostic results associated with these outcomes. Methods: This was a retrospective study of 126 equine keratomycosis cases between 2004 and 2020 with fungal infection confirmed on cytology, culture, and/or histopathology and a minimum of 1-month follow-up. Details of the ophthalmic examination, diagnostic test results, and treatment and cost outcomes were recorded. Outcomes of interest were analyzed by treatment type. The relationship of pat...
Mazzuchini MP, Lisboa FP, de Castro JI, Alvarenga MA, Segabinazzi LGTM, Canisso IF.Endometritis is the leading cause of subfertility in horses, and it is a clinical problem where historically antibiotics have not always been used with prudent justification. Because of this, alternative therapies to treat endometritis are necessary for the rational use of antibiotics. Objective: To assess the in vitro antimicrobial activity of non-traditional therapies commonly used in clinical practice against microorganisms causing infectious endometritis in mares. Methods: In vitro experiments. Methods: A microdilution technique was performed to determine the minimum inhibitory concentrati...
Sreenivasan CC, Naveed A, Uprety T, Soni S, Jacob O, Adam E, Wang D, Li F.Using metagenomic sequencing we identified equine rotavirus group B (ERVB) of ruminant origin in foal diarrhea outbreaks in the 2021 foaling season. To further investigate ERVB occurrence and determine its environmental stability, we collected mare and foal fecal samples from different farms in Central Kentucky during the 2022 foaling season. The RT-qPCR-based analyses showed that ERVB genome was detected in 16.67 % (42/252) of surveyed mare samples and 26.56 % (34/128) of foal samples. Furthermore, 94.12 % (16/17) of collected soil samples and 100 % (13/13) of water samples obtained f...
Sasaki Y, Suzuki S, Kusaba N, Rahman N, Aikawa C, Okamura M.In recent years, reported cases of salmonellosis in cattle and horses in Hokkaido, Japan, have increased. To optimize antimicrobial therapy, we assessed the antimicrobial susceptibility of Salmonella isolates from these animals. Among 112 bovine isolates, high resistance rates were observed for streptomycin (92.0%), ampicillin (88.4%), and tetracycline (79.5%), while resistance rates for kanamycin (8.9%), ciprofloxacin (1.8%), gentamicin (0.0%), and colistin (0.0%) were low. Additionally, 18.8% of the bovine isolates were resistant to cefotaxime, and all of these cefotaxime-resistant isolates ...
Sasaki M, Fukumoto N, Fukumoto S.A two-year-old male Japanese draft horse (known as a "Ban'ei horse") excreted eight cestodes. Based on their morphological features, they were identified as Anoplocephala perfoliata. The partial mitochondrial cytochrome c oxidase subunit 1 (COI) sequences of the worms were nearly identical to A. perfoliata isolated from horses in Europe. The results of phylogenetic analyses of COI revealed that our samples and the European isolates formed the same clade, which was separate from Chinese and Australian isolates. Ban'ei horses were developed by crossbreeding draft horses imported from European co...
Kambayashi Y, Nemoto M, Ochi A, Kishi D, Ueno T, Tsujimura K, Bannai H, Kawanishi N, Ohta M, Suzuki T.In this study, equine intestinal enteroids (EIEs) were generated from the duodenum, jejunum, and ileum and inoculated with equine coronavirus (ECoV) to investigate their suitability as in vitro models with which to study ECoV infection. Immunohistochemistry revealed that the EIEs were composed of various cell types expressed in vivo in the intestinal epithelium. Quantitative reverse-transcription PCR (qRT-PCR) and virus titration showed that ECoV had infected and replicated in the EIEs. These results were corroborated by electron microscopy. This study suggests that EIEs can be novel in vitro ...
Manikantan V, Ripley NE, Nielsen MK, Dangoudoubiyam S.Parascaris spp. represent a significant threat to equine health worldwide, particularly in foals. The long-term survival of parasites in the host necessitates persistent modulation of the host immune response. Intercellular communication achieved through the exchange of molecules via extracellular vesicles (EVs) released from the parasite could be a crucial factor in this regard. This study aimed to isolate and characterize EVs released by adult male and female Parascaris worms and conduct a proteomic analysis to identify sex-specific proteins and potential immunomodulatory factors. Methods: L...
Nishimura F, Fukushi N, Sakai H, Fukushi H.Equine herpesvirus type 1 (EHV-1) causes abortion, respiratory infection, and neurological diseases (equine herpesvirus myeloencephalopathy) in horses. A single nucleotide polymorphism (SNP) associated with a single amino acid in the DNA polymerase gene (ORF30, in which D752 is neuropathogenic and N752 is non-neuropathogenic) of EHV-1 has been associated with neuropathogenicity in horses. We constructed an EHV-1 Ab4p ORF30 N752 mutant and a repair virus to examine the effect of a D752N mutation on the neuropathogenicity of the virus in Syrian hamsters. The N752 mutation did not affect viral gr...
Haywood LMB, Sheahan BJ.Equine colitis is a devastating disease with a high mortality rate. Infectious pathogens associated with colitis in the adult horse include Clostridioides difficile, Clostridium perfringens, Salmonella spp., Neorickettsia risticii/findlaynesis, and equine coronavirus. Antimicrobial-associated colitis can be associated with the presence of infectious pathogens. Colitis can also be due to non-infectious causes, including non-steroidal anti-inflammatory drug administration, sand ingestion, and infiltrative bowel disease. Current treatments focus on symptomatic treatment (restoring fluid and elect...
Fahey MJ, Harman RM, Thomas MA, Pugliese BR, Peters-Kennedy J, Delco ML, Van de Walle GR.We aimed to study the antimicrobial and pro-healing potential of equine mesenchymal stromal cell secreted products (i.e. secretome), collected as conditioned media (mesenchymal stromal cell-conditioned media, MSC CM), in a novel in vivo model of methicillin-resistant Staphylococcus aureus (MRSA)-inoculated equine thorax wounds. Methods: Prospective in vivo study. Methods: Two Thoroughbred geldings. Methods: Six full-thickness cutaneous wounds were created bilaterally on the dorsal thorax of two horses (n = 12 wounds/horse). Wounds on the left thoraces were inoculated with MRSA on day 0. Al...
Samir A, Abdel-Moein KA, Zaher HM.The upsurge of diarrheagenic E. coli pathotypes carrying extended-spectrum beta-lactamases (ESBLs)/plasmid-mediated AmpC β-lactamase (pAmpC) among animals constitutes an emerging threat for humans and animals. This study investigated the burden of ESBL-/pAmpC-producing diarrheagenic E. coli among diarrheic foals and its potential public health implications. Rectal swabs were collected from 80 diarrheic foals. These swabs were processed to isolate and identify ESBL/pAmpC-producing E. coli using a selective culture medium, biochemical tests, phenotypic identification, and molecular identificati...
Nayel M, Kasem S, Fukushi N, El-Habashi N, Elsify A, Salama A, Hassan H, Yanai T, Ohya K, Fukushi H.Equine herpesvirus type 1 (EHV-1) causes rhinopneumonitis, abortion, and neurological outbreaks (equine herpesvirus myeloencephalopathy, EHM) in horses. EHV-1 also causes lethal encephalitis in small laboratory animals such as mice and hamsters experimentally. EHV-1 ORF76 is a homolog of HSV-1 US9, which is a herpesvirus kinase. Starting with an EHV-1 bacterial artificial chromosome clone of neuropathogenic strain Ab4p (pAb4p BAC), we constructed an ORF76 deletion mutant (Ab4p∆ORF76) by replacing ORF76 with the rpsLneo gene. Deletion of ORF76 had no influence on replication, cell-to-cell spr...
Parkinson NJ, Ward A, Malbon AJ, Reardon RJM, Kelly PG.Equine sarcoids are common non-metastasising skin tumours in horses, associated with bovine papillomavirus (BPV) infection. Six subtypes are recognised (occult, verrucose, nodular, fibroblastic, mixed and malevolent lesions), with variable clinical behaviour. The pathophysiology underlying varying tumour phenotype is poorly understood, and previous data on associations with viral load have been conflicting. To better understand this clinical variation, we investigated associations between tumour subtype and viral load, viral early protein gene expression, and expression of 10 host genes by qua...
Dubey JP, Gupta A, Calero-Bernal R, de Araujo LS, García-Gil ML, Battle J, Ankarah A, Van Why K, Brown JD, Rosenthal BM.The protozoan Sarcocystis neurona can cause severe disease in horses, marine mammals, and several other animal species in North America. The Virginia opossum (Didelphis virginiana) is its definitive host, and the raccoon (Procyon lotor) has been considered its primary intermediate host in the USA. Although canids have not previously been identified as important intermediate hosts for this parasite, we here report several natural cases in the gray fox (Urocyon cinereoargenteus). We identified muscular infections in 11 (23.9 %) of 46 gray foxes from Pennsylvania, USA. In hematoxylin and eosin ...
Agerholm JS, Damborg P, Christoffersen M.Streptococci are well-known opportunistic bacterial abortifacients in mares. Colonization of the pregnant uterus is considered to happen after transcervical migration of bacteria from the lower genital tract mucosa. Streptococcus ovis is a pathogen mainly associated with inflammatory lesions in sheep. This species has not been reported in association with disease in horses. In the present case, S. ovis was isolated in monoculture from the lung of an 8-months-old equine fetus and was associated with development of acute suppurative bronchopneumonia, umbilical cord cellulitis and placentitis in ...
Van Mol B, Oosterlinck M, Janssens S, Buys N, Pille F.Various environmental and genetic risk factors are linked to the pathogenesis of equine osteochondrosis and osteochondral fragments in the fetlock joint. Therefore, a scoping review was conducted to describe current evidence linking genetic factors and environmental factors of these osteochondral disorders. This article constitutes the first part of this scoping review and focuses on environmental factors, with the second part addressing genetic factors. To identify potentially relevant papers online bibliographical databases PubMed and Web of Science were utilised, supplemented with articles ...
Lin Y, Wang Y, Li H, Liu T, Zhang J, Guo X, Guo W, Wang Y, Liu X, Huang S, Liao H, Wang X.Single B cells-based antibody platforms offer an effective approach for the discovery of useful antibodies for therapeutic or research purposes. Here we present a method for screening equine immunoglobins F(ab)2, which offers the potential advantage of reacting with multiple epitopes on the virus. Using equine influenza virus (EIV) as model, a hemagglutinin (HA) trimer was constructed to bait B cells in vaccinated horses. We screened 370 HA-specific B cells from 1 × 10 PBMCs and identified a diverse set of equine variable region gene sequences of heavy and light chains and then recombined wit...
Ali YH, Mohieddeen TAG, Abdellatif MM, Ahmed BM, Saeed IK, Attaalfadeel HM, Ali AA.Rabies is endemic in Sudan with continuing outbreaks occurring annually, the most common animals affected are dogs, followed by goats and equids. This work focused on equid rabies, to elucidate the current situation of the disease through analysis of reports of equid rabies outbreaks in Sudan during 2010-2022 supported by laboratory confirmation of the disease. During the study period, 66 animals were affected during 35 equid rabies outbreaks. The highest incidences were found in Al Gezira (30.3%), followed by Darfur (24.2%) and Kordofan (15.2%). The highest incidence rate was observed during ...
Morrison AC, Ferro C, Tesh RB.Blood meals from 579 Lutzomyia longipalpis (Diptera:Psychodidae), collected in an endemic focus of American visceral leishmaniasis in Colombia, were identified by precipitin test. Sand fly collections were made during a 16-month period from the inside walls of two houses, a pigpen, and rock crevices in a small community (El Callejon) within the endemic area. Feeding patterns of the sand flies varied with locality and date of collection. Overall, bovine feedings predominated, but feedings were also recorded on pigs, equines, humans, dogs, opossums, birds, and reptiles. Calculation of the forage...
Madigan JE, Hietala S, Chalmers S, DeRock E.The prevalence of antibodies to Ehrlichia equi in horses from the foothill regions of northern California and from the Sacramento valley (non-foothill area) was determined, using an indirect fluorescent antibody test. Horses from foothill regions had a higher prevalence of seropositivity (10.4%) and higher titer (1:10 to 1:80) than did those from non-foothill regions (3.1%; titer less than or equal to 1:10). Fifty percent of healthy horses on a foothill farm enzootic for E equi had titer to E equi, suggesting that infection with E equi can be subclinical. Six veterinarians surveyed from northe...
Rüegg SR, Torgerson P, Deplazes P, Mathis A.Epidemiological factors of tick-borne equine piroplasmoses, caused by Theileria equi and Babesia caballi, were investigated using logistic regression (GLM) and general additive models (GAM) based on the prevalences determined in 510 domestic horses and in ticks in S.W. Mongolia by indirect immunofluorescence antibody test (IFAT) and/or multiplex PCR. Prevalences of T. equi and B. caballi in horses were 66.5% (95% CI: 62.1-70.7) and 19.1% (15.6-22.9), respectively by PCR and 78.8% (74.9-82.3) and 65.7% (61.3-69.9) by IFAT. Of 166 ticks analysed from PCR- and IFAT-negative horses 1 was PCR posit...
Apostolakos I, Franz E, van Hoek AHAM, Florijn A, Veenman C, Sloet-van Oldruitenborgh-Oosterbaan MM, Dierikx C, van Duijkeren E.To investigate the occurrence and characteristics of ESBL/AmpC-producing Escherichia coli in faecal samples from horses at one equine clinic in the Netherlands. A total of 91 horses, including residents and patients, were sampled. ESBL/AmpC-producing E. coli were identified by a combination disc diffusion test. Phylogenetic groups and MLST were determined. ESBL/AmpC genes were analysed using PCR and sequencing. Plasmids were characterized by transformation and PCR-based replicon typing. Subtyping of plasmids was done by plasmid MLST. At least one E. coli isolate with a confirmed ESBL/AmpC gene...
Horohov DW.The modern horse, Equus caballus has historically made important contributions to the field of immunology, dating back to Emil von Behring's description of curative antibodies in equine serum over a century ago. While the horse continues to play an important role in human serotherapy, the mouse has replaced the horse as the predominant experimental animal in immunology research. Nevertheless, continuing efforts have led to an improved understanding of the equine immune response in a variety of infectious and non-infectious diseases. Based on this information, we can begin to identify specific ...
Payne SL, Salinovich O, Nauman SM, Issel CJ, Montelaro RC.Comparisons of peptide and oligonucleotide maps of glycoproteins and RNA from nine isolates of equine infectious anemia virus (EIAV) that were generated during parallel infections of two Shetland ponies revealed that each isolate was structurally unique. Each EIAV isolate contained a unique subset of variant peptides, oligonucleotides, or both, indicating that structural variation in EIAV is a random and noncumulative process and that a large spectrum of possible EIAV variants can be generated in infected animals.
Bilzer T, Planz O, Lipkin WI, Stitz L.Tissues from 9 horses and 1 donkey suffering from natural Borna disease were investigated immunomorphologically. Lymphocytic inflammatory reactions and increased expressions of MHC class I and class II antigen were found in the brain as well as in the trigeminal and olfactory system. Perivascular inflammatory infiltrates were dominated by CD4+ T cells, whereas the majority of CD8+ T cells were disseminated intraparenchymally. No evidence of inflammation was found in the retina. Borna disease virus proteins and nucleic acids were present in the hippocampus, thalamus and medulla oblongata in all...
Scoles GA, Hutcheson HJ, Schlater JL, Hennager SG, Pelzel AM, Knowles DP.We report an outbreak of equine piroplasmosis in southern Texas, USA, in 2009. Infection prevalence reached 100% in some areas (292 infected horses). Amblyomma cajennense was the predominant tick and experimentally transmitted Theileria equi to an uninfected horse. We suggest that transmission by this tick species played a role in this outbreak.
Weiss M, Horzinek MC.In equine dermis cells infected with Berne virus particles were first detected 10 h after infection. Virions were encountered in all parts of the Golgi system and, infrequently, in the rough endoplasmic reticulum. A unique form of budding of preassembled rigid tubular nucleocapsids was demonstrated. Masses of tubular nucleocapsids of a lesser diameter and electron density were prominent in the cytoplasm and the nucleus of infected cells. Within the Golgi system and cytoplasmic cisternae virions appeared as straight or slightly curved rods. Extremely long, aberrant virions (250 nm) were occasio...
Raza A, Qamar AG, Hayat K, Ashraf S, Williams AR.Control of equine nematodes has relied on benzimidazoles (BZs), tetrahydropyrimidines and macrocyclic lactones. The intensive use of anthelmintics has led to the development of anthelmintic resistance (AR) in equine cyathostomins and Parascaris equorum. Field studies indicate that BZ and pyrantel resistance is widespread in cyathostomins and there are also increasing reports of resistance to macrocyclic lactones in cyathostomins and P. equorum. The unavailability of reliable laboratory-based techniques for detecting resistance further augments the problem of nematode control in horses. The onl...
Taylor S.Sepsis is defined as an exaggerated, systemic inflammatory response to infection and is a common condition in horses. Systemic inflammatory response syndrome (SIRS) associated with bacterial infection is a hallmark of sepsis. Sepsis in neonatal foals is a common sequela of failure of passive transfer and, in addition to development of SIRS, may be characterised by bacteraemia, pneumonia, enterocolitis, omphalophlebitis, meningoencephalitis or arthritis. Sepsis in mature horses is most commonly observed secondary to gastrointestinal lesions that result in disrupted mucosa and bacterial transloc...
Bhoora R, Quan M, Franssen L, Butler CM, van der Kolk JH, Guthrie AJ, Zweygarth E, Jongejan F, Collins NE.A quantitative real-time polymerase chain reaction (qPCR) assay using a TaqMan minor groove binder (MGB) probe was developed for the detection of Babesia caballi infection in equids from South Africa. Nine previously published sequences of the V4 hypervariable region of the B. caballi 18S rRNA gene were used to design primers and probes to target unique, conserved regions. The B. caballi TaqMan MGB qPCR assay was shown to be efficient and specific. The detection limit, defined as the concentration at which 95% of positive samples can be detected, was determined to be 0.000114% parasitized eryt...
Orrego A, Issel CJ, Montelaro RC, Adams WV.Five serial passages of a cell-adapted strain of equine infectious anemia (EIA) virus were conducted in Shetland ponies. The 13 recipient ponies became agar-gel immunodiffusion test-positive by 25 days after they were inoculated. The virulence of the cell-adapted strain of EIA virus markedly increased through 3 serial passages, although individual variation within passages was high. The 1st serial-passage recipient remained afebrile through 200 days, whereas a febrile episode occurred about every 185, 44, 35, and 33 days in the 2nd, 3rd, 4th, and 5th serial-passage recipients, respectively. Se...
Weissenböck H, Bagó Z, Kolodziejek J, Hager B, Palmetzhofer G, Dürrwald R, Nowotny N.Borna disease, a lethal infection with Borna disease virus-1 (BoDV-1), was diagnosed in four horses from Upper Austria in 2015 and 2016. All cases occurred in winter (two cases in February 2015 and two cases in December 2016), and the maximal distance of the affected stables was 17 km. To demonstrate whether the causative agent was also harbored by its reservoir host, the bicolored white-toothed shrew (Crocidura leucodon), 28 shrews from this geographic area were collected in 2015 and investigated for the presence of BoDV-1. The shrew species were identified according to taxonomic clues and ...
McDade JE.Ehrlichiae are one of several kinds of obligate intracellular bacteria. Taxonomically, they are grouped with rickettsiae, but they can be distinguished by their unique tropism for circulating leukocytes. Ehrlichia canis causes a pancytopenia in dogs that becomes chronic if untreated. Certain breeds develop severe infections, characterized by fever, anorexia, dramatic weight loss, marked pancytopenia, anemia, peripheral edema, and hemorrhage. Ehrlichia risticii, a recently discovered species, is the cause of a serious diarrheal disease of horses. Other species of ehrlichiae have been documented...
Verma A, Stevenson B, Adler B.Leptospirosis in horses has been considered a relatively uncommon infection. However, recent data suggest that the infection is widespread, with the incidence and infecting serovars varying considerably in different geographical regions. The majority of infections remain asymptomatic. Clinical signs in equine leptospirosis resemble those seen in other animal species. However, leptospirosis as a cause of acute respiratory distress is becoming more frequently recognised. A particular feature of equine leptospirosis is post infection recurrent uveitis (moon blindness or periodic ophthalmia), whic...
Stasiak K, Dunowska M, Rola J.Equid herpesviruses (EHVs) are widespread in equine populations worldwide. While the infection with equine α-herpesviruses (EHV-1 and EHV-4) has been linked to several clinical outcomes, the pathogenic potential for equine γ-herpesviruses (EHV-2 and EHV-5) is still unclear. The objective of the current study was to determine the prevalence of infection with EHVs among Polish horses, to investigate factors associated with EHV infections among horses sampled, and to determine genetic variability within Polish EHV-2 isolates. Virus-specific real-time PCR assays were used for detection of EHV-1,...
Gold JJ, Heath IB, Bauchop T.Vegetative and reproductive stages of Caecomyces equi gen. nov., sp. nov. isolated from the horse caecum were examined by light and electron microscopy. This organism, which is similar to isolates known as Sphaeromonas communis, produces uniflagellate, uninucleate zoospores whose perikinetosomal structures, i.e. circumflagellar ring, spur, struts and scoop, are similar in many respects to those described in species of Neocallimastix. Microtubular roots extend basally from the spur and associate with hydrogenosomes and the nucleus. Another group of microtubules radiates laterally in a fan-shape...
Oyarzun-Ampuero F, Vidal A, Concha M, Morales J, Orellana S, Moreno-Villoslada I.The treatment of skin wounds represents an important research area due to the important physiological and aesthetic role of this tissue. During the last years, nanoparticles have emerged as important platforms to treat skin wounds. Silver, gold, and copper nanoparticles, as well as titanium and zinc oxide nanoparticles, have shown potential therapeutic effects on wound healing. Due to their specific characteristics, nanoparticles such as nanocapsules, polymersomes, solid lipid nanoparticles, and polymeric nanocomplexes are ideal vehicles to improve the effect of drugs (antibiotics, growth fact...
de Jong NWM, Vrieling M, Garcia BL, Koop G, Brettmann M, Aerts PC, Ruyken M, van Strijp JAG, Holmes M, Harrison EM, Geisbrecht BV, Rooijakkers SHM.Staphylococcus aureus is a versatile pathogen capable of causing a broad range of diseases in many different hosts. S. aureus can adapt to its host through modification of its genome (e.g. by acquisition and exchange of mobile genetic elements that encode host-specific virulence factors). Recently, the prophage φSaeq1 was discovered in S. aureus strains from six different clonal lineages almost exclusively isolated from equids. Within this phage, we discovered a novel variant of staphylococcal complement inhibitor (SCIN), a secreted protein that interferes with activation of the human complem...
Allen GP, Breathnach CC.Neurological disease in horses caused by infection with certain 'paralytic' strains of equine herpesvirus-1 (EHV-1) is a potentially devastating condition the pathogenesis of which is poorly understood. Preliminary observations in both experimentally induced and naturally occurring cases of the central nervous system disease have revealed a more robust cell-associated viraemia in horses infected with paralytic isolates of EHV-1, relative to horses infected with abortigenic isolates. To investigate further this pathogenesis-relevant question, the present study was performed using a greater numb...
Canever RJ, Braga PR, Boeckh A, Grycajuck M, Bier D, Molento MB.The increase of anthelmintic resistance in the last years in the nematode population of veterinary importance has become a major concern. The objective of the present study was to evaluate the efficacy of the main anthelmintic drugs available in the market against small strongyles of horses in Brazil. A total of 498 horses from 11 horse farms, located in the states of Paraná, São Paulo, Rio de Janeiro and Minas Gerais, in Brazil, were treated with ivermectin, moxidectin, pyrantel and fenbendazole, orally at their recommended doses. The fecal egg count reduction test (FECRT) was used to deter...
Christley RM, Hodgson DR, Rose RJ, Wood JL, Reids SW, Whitear KG, Hodgson JL.In order to investigate the role of infectious agents in the aetiology of lower respiratory tract disease in Thoroughbred racehorses, a matched case-control study was conducted. Cases were identified by the presence of coughing, and were compared to a control population matched on time of sample collection and location within the same training establishment. Tracheal wash samples were collected from 100 cases and 148 controls. Case horses were more likely than controls to have endoscopic and cytological evidence of airway inflammation. There was no significant association between serological e...
Belshan M, Harris ME, Shoemaker AE, Hope TJ, Carpenter S.Sequence analysis identified significant variation in the second exon of equine infectious anemia virus (EIAV) rev. Functional analysis indicated that limited amino acid variation in Rev significantly altered the export activity of the protein but did not affect Rev-dependent alternative splicing. EIAV Rev can mediate export through two independent cis-acting Rev-responsive elements (RREs), and differences among Rev variants were more pronounced when both RREs were present. Variation in Rev may be an important mechanism for regulation of virus replication in vivo and may contribute to changes ...
Frye JG, Fedorka-Cray PJ.Third-generation cephalosporin (3GC) antimicrobials are the drugs of choice for treatment of salmonellosis in children. Salmonella isolated in the USA are assayed by the National Antimicrobial Resistance Monitoring System (NARMS) for resistance to antimicrobials including first-, second- and third-generation cephalosporins. From 1999 to 2003, 34,411 Salmonella were isolated from animals in the USA, of which 10.9% were found to be resistant to ceftiofur, a 3GC used in animals, whilst only 0.3% were resistant to ceftriaxone, a 3GC used in human medicine. Ceftiofur resistance rose from 4.0% in 19...
Summerfield A, Auray G, Ricklin M.Dendritic cells (DC) have a main function in innate immunity in that they sense infections and environmental antigens at the skin and mucosal surfaces and thereby critically influence decisions about immune activation or tolerance. As professional antigen-presenting cells, they are essential for induction of adaptive immune responses. Consequently, knowledge on this cell type is required to understand the immune systems of veterinary mammals, including cattle, sheep, pigs, dogs, cats, and horses. Recent ontogenic studies define bona fide DC as an independent lineage of hematopoietic cells orig...
Pusterla N, Barnum S, Miller J, Varnell S, Dallap-Schaer B, Aceto H, Simeone A.Here we report on an EHV-1 outbreak investigation caused by a novel genotype H752 (histidine in amino acid position 752 of the ORF 30 gene). The outbreak involved 31 performance horses. Horses were monitored over a period of 35 days for clinical signs, therapeutic outcome and qPCR results of EHV-1 in blood and nasal secretions. The morbidity of the EHV-1 outbreak was 84% with 26 clinically infected horses displaying fever and less frequently anorexia and distal limb edema. Four horses showed mild transient neurological deficits. Clinically diseased horses experienced high viral load of EHV-1 i...
Crispe E, Finlaison DS, Hurt AC, Kirkland PD.During the equine influenza (EI) outbreak, respiratory disease was observed in dogs that were in close proximity to infected horses. Investigations were undertaken to exclude influenza virus infection. Of the 23 dogs that were seropositive in tests using the influenza A/Sydney/2007 virus as the test antigen, 10 showed clinical signs. EI virus appeared to be readily transmitted to dogs that were held in close proximity to infected horses, but there was no evidence of lateral transmission of the virus to other dogs that did not have contact with or were not held in close proximity to horses.
Yager JA.The pathogenesis of Rhodococcus equi pneumonia in foals is reviewed. The main routes of infection are respiratory and alimentary. The latter is probably the chief route of exposure in all foals and probably leads to development of specific immunity. Susceptible foals, those whose maternal immunity wanes before generation of their own immune response, readily develop disease if exposed aerogenously to sufficient numbers of R. equi. Management and environmental circumstances have a major role to play in determining the magnitude of this challenge and, therefore, in the prevalence of the disease....
Garner MR, Flint JF, Russell JB.When cattle and horses are fed large amounts of grain, histamine can accumulate in the gastrointestinal tract, and this accumulation can cause an acute inflammation of the hooves (laminitis). When ruminal fluid from dairy cattle fed grain supplements was serially diluted in anaerobic MRS medium containing histidine (50 mM), histamine was detected at dilutions as high as 10(-7). The histidine enrichments were then transferred successively in an anaerobic, carbonate-based medium (50 mM histidine) without glucose. The histamine producing bacteria could not be isolated from the rumens of cattle fe...
