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.
Schiele AR, Valletti C, Ringer SK.A Trotter mare (aged 5 years 8 months) presented with severe thoracic limb lameness 2 years after screw fixation of a third carpal bone fracture. Septic arthritis of the intermediate carpal joint necessitated three anaesthetics: two arthroscopic lavages in dorsal recumbency, followed by a computed tomography-guided screw explantation with curettage of an infected, sclerotic third carpal bone in right lateral recumbency. For each anaesthetic, maintenance was with isoflurane carried in oxygen and air, and a medetomidine constant rate infusion. Twelve days after the third anaesthetic, the horse h...
Baghdadi HBA, Abdelsalam M, Attia MM.Strongylus vulgaris, a devastating parasitic nematode in equids, causes life-threatening verminous aneurysms that are challenging to diagnose early. This study pioneered integrating nanotechnology into an indirect enzyme-linked immunosorbent assay (i-ELISA) system to enhance the sensitivity and specificity for detecting S. vulgaris larval antigens in equine serum samples, with PCR confirmation of the species. A conventional i-ELISA and an innovative nano-based ELISA were developed using excretory-secretory antigens from adult S. vulgaris worms. The nano-ELISA incorporated gold nanoparticles (1...
Benitez-Ibalo AP, Debárbora VN, Mangold AJ, Nava S, Sebastian PS.After the previous description and characterization of Theileria equi sensu stricto (Genotype A) in Argentina, the aim of the present study was to investigate the possible heterogeneity of 18 S rDNA genotypes circulating in this country. Therefore, blood samples from 18 horses from two different neighborhoods of Corrientes City, Corrientes Province, were analyzed for infection with Theileria species. Theileria DNA was detected in five samples (27.8%). Four nearly complete 18 S rDNA gene sequences were obtained and phylogenetic analyses were carried out. The maximum likelihood tree constructe...
Equine infectious anemia virus (EIAV) is the simplest described within the family, related to the human immunodeficiency viruses (HIV-1 and HIV-2). There is an important interplay between host cells and viruses. Viruses need to hijack cellular proteins for their viral cycle completion and some cellular proteins are antiviral agents interfering with viral replication. HIV cellular partners have been extensively studied and described, with a special attention to host proteins able to inhibit specific steps of the viral cycle, called restriction factors. Viruses develop countermeasures against ...
Rabei ȘO, Cârstolovean AS, Culda CA, Mihalca AD.This is the first study that targets the epidemiology of Gasterophilus spp. in slaughtered horses from Romania. Previously to our research, there were five recorded species: Gasterophilus haemorrhoidalis, Gasterophilus inermis, Gasterophilus intestinalis, Gasterophilus nasalis, and Gasterophilus pecorum with a dispersed distribution throughout the country, the data being recorded more than 73 years ago. The collection of Gasterophilus larvae was carried out from the digestive system (stomach, duodenum, and rectum) of horses in three abattoirs, monthly between January 2023 and December 2023. Fo...
Valderrama-Martinez C, Packham A, Zheng S, Smith W, Plancarte M, Aleman M.Evaluating antibody titers for Sarcocystis neurona for the diagnosis of equine protozoal myeloencephalitis from serum samples is a common practice. However, ensuring timely and proper refrigeration is not always possible. Objective: To evaluate immunofluorescent antibody (IFA) titers for S. neurona from serum samples stored at room temperature and 4°C. Methods: Twenty-two serum samples. Methods: Prospective longitudinal study. Two serum aliquots of 1 mL each were stored at room temperature (20-23.3°C) and 4°C. The unrefrigerated aliquot was immediately tested for IFA titers. Both aliquots...
Hepworth-Warren KL, Love K.Bacterial pneumonia is a common disease in adult horses, but there are no guidelines for practitioners regarding risk factors, diagnosis, and management of the disease. The objectives of this study were to describe how a group of equine veterinarians diagnose and treat bacterial pneumonia in adult horses. A 22-question survey was distributed via multiple platforms to equine veterinarians asking questions regarding the frequency with which they identified specific clinical findings and used certain diagnostic modalities, and the approach to antimicrobial and adjunct therapy. Three hundred nine ...
Smith MZ, York M, Townsend KS, Martin LM, Gull T, Coghill LM, Ericsson AC, Johnson PJ.Whereas restoration of fecal consistency after treatment with clioquinol for chronic diarrhea and free fecal water syndrome has been attributed to its antiprotozoal properties, actions of clioquinol on the colonic bacterial microbiota have not been investigated. Objective: Characterize the dynamics of fecal microbial diversity before, during, and after PO administration of clioquinol to healthy horses. Methods: Experimental prospective cohort study using a single horse group. Methods: Eight healthy adult horses received PO clioquinol (10 g, daily) for 7 days. Feces were obtained daily for ...
Bull KE, Hodgkinson J, Allen K, Poissant J, Peachey LE.Cyathostomins are the most abundant equid endoparasites globally. There are approximately fifty cyathostomin species and, whilst they occupy distinct niches within the large intestine, they are generally considered to share similar characteristics in terms of pathogenicity and response to drug treatment. There are three classes of anthelmintic licensed in the UK to treat cyathostomins (benzimidazoles, tetrahydropyrimidines and macrocyclic lactones) and cases of resistance have been documented for all classes. Previously, faecal egg count reduction tests (FECRT) on four UK Thoroughbred studs re...
Pusterla N, Lawton K, Barnum S, Ross K, Purcell K.The objective of this study was to describe an outbreak of equine herpesvirus-1 myeloencephalopathy (EHM) in a population of aged equids. The outbreak was linked to the introduction of five healthy non-resident horses 15 days prior to the first case of acute recumbency. This fulminant EHM outbreak was predisposed by the grouping of the 33 unvaccinated animals in two large pens with shared water and feed troughs. Fourteen horses (42.4%) developed neurological deficits within the first week of the outbreak. Four additional equids developed fever and respiratory signs (EHV-1 infection), while fif...
Ma AZ, Yeo YY, Lee JF, Kim CM, Ezzatpour S, Menchaca C, Upadhye V, Annand EJ, Eden J-S, Plowright RK, Peel AJ, Buchholz DW, Aguilar HC.A novel Hendra virus (HeV) genotype (HeV genotype 2 [HeV-g2]) was recently isolated from a deceased horse, revealing high-sequence conservation and antigenic similarities with the prototypic strain, HeV-g1. As the receptor-binding (G) and fusion (F) glycoproteins of HeV are essential for mediating viral entry, functional characterization of emerging HeV genotypic variants is key to understanding viral entry mechanisms and broader virus-host co-evolution. We first confirmed that HeV-g2 and HeV-g1 glycoproteins share a close phylogenetic relationship, underscoring HeV-g2's relevance to global he...
Nakamae Y, Elce YA, Saab ME, McClure JT, Doyle AJ.Alcohol-based antisepsis has shown experimentally to be as effective as 4% chlorhexidine gluconate (CHG) at reducing bacterial counts (colony forming units; CFU) on equine skin. Our objectives were to determine the immediate and post-surgical reduction in CFU/mL on equine skin prepared with CHG-based or 70% isopropyl alcohol (IPA)-based (without CHG) protocols in a clinical setting with arthroscopic surgery. Our hypotheses were that the logCFU/mL reduction would not significantly differ between protocols immediately after preparation or at the end of surgery. Six horses underwent a 40 min bila...
Cabete A, Xufre Â, Padre L, Bettencourt E, Nunes T, Gomes J.Equine piroplasmosis (EP) is a tick-borne disease of equids caused by Theileria equi, Theileria haneyi, and Babesia caballi. EP is endemic in most tropical and subtropical regions worldwide, and there is a likelihood that it is also endemic in Portugal. This retrospective study aimed to determine the seroprevalence, prevalence, and potential risk factors of EP in our country over the past five years. A total of 3063 diagnostic test records were analysed. Results from the competitive enzyme-linked immunosorbent assay (cELISA) revealed a seroprevalence of 32.7 % and 15.7 % for T. equi and B....
Bishop RC, Nobrega AD, Mersich I, Wilkins PA.To describe indications for and demonstrate the technique to perform a transtracheal aspirate in horses. Transtracheal aspirate is indicated to collect samples for cytology and bacteriologic culture in cases of suspected pneumonia or other lower respiratory tract disease. Methods: 1 healthy university-owned horse was used for demonstration purposes. Images of clinical case samples from the University of Illinois Veterinary Teaching Hospital are shown. Methods: The horse is restrained and sedated with detomidine or xylazine to facilitate restraint and butorphanol to minimize coughing. The ventr...
Toft K, Honoré ML, Ripley N, Nielsen MK, Mardahl M, Fromm B, Hedberg-Alm Y, Tydén E, Nielsen LN, Nejsum P, Thamsborg SM, Cirera S, Pihl TH.The equine bloodworm, Strongylus vulgaris, is a common and highly pathogenic parasite in horses due to its migratory life cycle involving the intestinal arteries. Current diagnostic techniques cannot detect the prepatent migrating stages of S. vulgaris, highlighting the need for new biomarkers. Parasites release microRNAs (miRNAs) into their environment, which could potentially be detectable in host blood samples. Additionally, host miRNA expression patterns may change in response to infection. This study aimed to identify miRNAs associated with S. vulgaris infection by profiling the horse's m...
McCreight KA, Barbosa LN, Odoi A, Reed P, Rajeev S.We estimated the seroprevalence in dogs, cats, and horses from Tennessee, USA, using the microscopic agglutination test (MAT) against 12 serovars. We observed seropositivity in 110 of 374 (29.4%) dogs, 21 of 170 (12.4%) cats, and 42 of 88 (47.7%) horses. The highest seroprevalence was observed for serovars Autumnalis (74.6%) in dogs, and Bratislava in cats (42.9%) and horses (95.2%). We found a significant level of potential cross-reactivity between multiple serovars tested, with highest cross-reactivity to serovar Autumnalis in dogs. seroprevalence was significantly higher in vaccinated ...
Ahn S, Redman EM, Gavriliuc S, Bellaw J, Gilleard JS, McLoughlin PD, Poissant J.Identifying factors that drive among-individual variation in mixed parasitic infections is fundamental to understanding the ecology and evolution of host–parasite interactions. However, a lack of non-invasive diagnostic tools to quantify mixed infections has restricted their investigation for host populations in the wild. This study applied DNA metabarcoding on parasite larvae cultured from faecal samples to characterize mixed strongyle infections of 320 feral horses on Sable Island, Nova Scotia, Canada, in 2014 to test for the influence of host (age, sex and reproductive/social status) and ...
Kordowitzki P.Eastern equine encephalitis virus (EEEV) is a mosquito-transmitted alphavirus that, among humans, can cause a severe and often fatal illness. The zoonotic EEEV enzootic cycle involves a cycle of transmission between and avian hosts, frequently resulting in spillover to dead-end vertebrate hosts such as humans and horses. Interestingly, it has been described that the W132G mutation of the very low-density lipoprotein receptor (VLDLR), the receptor of EEEV, significantly enhanced the VLDLR-mediated cell attachment of EEEV. The patient's metabolism plays a pivotal role in shaping the complex lan...
Haenni M, Châtre P, Drapeau A, Cazeau G, Troncy J, François P, Madec JY.Enterobacter hormaechei is an important pathogen in humans and animals, which, in addition to its intrinsic AmpC, can acquire a wide variety of genes conferring resistances to extended-spectrum cephalosporins (ESCs) and carbapenems (CPs). In France, human clinical outbreaks of E. hormaechei resistant to ESC or carbapenem were reported. Objective: To study E. hormaechei isolates from cats and dogs (=59) as well as from horses (n = 55) presenting a non-susceptible phenotype to beta-lactams in order to determine which clones, resistance genes and plasmids are circulating in France. Methods: E. ho...
Fernandes CM, Prestes AS, Ianiski LB, Maciel AF, Noro BG, da Silva FD, Vizzotto BS, Botton SA, Schumacher RF, Pereira DIB, Barbosa NV.Pythiosis, caused by Pythium insidiosum, is an infectious and non-transmissible disease affecting horses, dogs, and humans, with no effective drug treatment available. Triazoles are compounds of interest for their potential pharmacological properties against fungi and bacteria. In this study, we synthesized three new triazole compounds (C1, C2, and C3) to assess their in vitro activities against P. insidiosum and their safety on human leukocytes. Susceptibility testing was performed against P. insidiosum isolates (n = 15) to determine the minimum inhibitory concentration (MIC) and minimum ...
Damdinjav B, Raveendran S, Mojsiejczuk L, Ankhanbaatar U, Yang J, Sadeyen JR, Iqbal M, Perez DR, Rajao DS, Park A, Viana M, Murcia PR.Recent outbreaks of influenza A(H5N1) have affected many mammal species. We report serologic evidence of H5N1 virus infection in horses in Mongolia. Because H3N8 equine influenza virus is endemic in many countries, horses should be monitored to prevent reassortment between equine and avian influenza viruses with unknown consequences.
Munirah M, Wahyuni S, Wahid I, Hamid F.In Indonesia, malaria incidence is at a high rate despite maximum preventive efforts. Therefore, this study aims to determine the possibility of a reservoir among domestic animals in malaria-endemic areas. Animal blood was collected using EDTA tubes, then smeared and stained with Giemsa for microscopic identification. About 10 μl of blood was dropped on to a filter paper to capture DNA. Nested PCR was used for parasite molecular detection, while species were identified using the sequenced DNA. A total of 208 and 62 animal blood samples were collected from Gaura village, West Sumba and Fak...
Magdesian KG.Knowledge of immunodeficiencies is crucial to neonatal medicine, in that they predispose to sepsis in the newborn and neonatal foal, as well as recurrent infections in older foals. The most common immunodeficiency in newborn and neonatal foals is failure of passive transfer, which is an example of an acquired immunodeficiency. Congenital or developmental immunodeficiencies may be transient or permanent, and can either affect the cell-mediated or humoral arms of immunity, and in some cases both. Affected foals often have chronic or recurrent respiratory or gastrointestinal infections, often wit...
Scott I, Lawrence KE, Gee EK.Shortened egg reappearance periods (ERP) have been seen as an early warning of anthelmintic resistance development in cyathostomins in horses. The hypothesis has been that in these instances, efficacy against egg laying adult cyathostomins remains high, but a decline in activity against later larval stages leads to the earlier resumption of egg shedding after treatment. In this study using a single herd of horses we investigated the ERP of a number of commonly used equine anthelmintics and examined whether ERP might show seasonal variation between winter and summer. Four main Faecal egg count ...
Nassar AFC, Chiebao DP, Fava CD, Miyashiro S, Castro V, Ogata RA, Yamamora JM, Monteiro CAS, Monteiro EJB.Glanders is a zoonotic disease of equids caused by the bacterium Burkholderia mallei, responsible for considerable economic loss. This study aimed to describe the clinical manifestations, pathological findings, and also bacteriological and molecular methods for agent detection in naturally infected animals (16 adult horses and one fetus) detected by serological survey from three glanders outbreaks. Of the 16 horses, 6 (37.5%) did not show clinical signs. After necropsy,samples of organs, lymph nodes, lesions and secretions were collectedfor histopathology, bacterial isolation, and PCR. The cli...
Farkas A, Thieme K, Soimala T, Jensen CK, Eule JC.This retrospective study evaluates the efficacy of povidone-iodine (PI) and polyhexamethylene biguanide (PHMB) as preoperative antiseptics in equine ophthalmic procedures. Methods: Horses that underwent routine ophthalmic surgery and procedures. Methods: Data were collected retrospectively from the medical records of equine patients undergoing ophthalmic procedures. Inclusion criteria were sampling for aerobic microbial culture at three different time points (T0: pre-irrigation, T1: post-irrigation, and T2: postoperatively) and T0 showing bacterial growth. Microbiological outcomes were assesse...
Padalino B, Pellegrini F, Felici M, Zappaterra M, Catella C, Cordisco M, Lorusso E, Cirone F, Pratelli A.Respiratory disorders (RDs) are a common transport-related welfare consequence in horses. This prospective study described the journeys of horses transported to two slaughterhouses in Italy, documented the prevalence of potentially RD-related pathogens, and identified possible predisposing factors. Data were recorded from arrival until 48 h after arrival and included the collection of Deep Nasopharyngeal Swabs (DNS), journey details and welfare assessment of horses (n = 155). PCR was used to quantify the presence of influenza A virus, reovirus, equine herpesvirus type 1 and 4, adenovirus, r...
Ma W, Gao L, Wu X, Zhong L, Huang X, Yang R, Wu H, Zhu L, Ma W, Peng L, Li B, Song J, Luo S, Bao F, Liu A.Both Borrelia burgdorferi (Bb) and Anaplasma phagocytophilum (Ap) can infect humans and animals through tick-borne transmission, resulting in zoonosis. Under certain conditions, human infection can lead to Lyme disease (LD) and human granulocytosis (HGA), whereas infection in animals can cause various acute and non-specific symptoms. The combination of Bb and Ap has been reported to increase the disease severity in infected animals. In this systematic review and meta-analysis, we investigated the global diversity of Bb and Ap coinfection in animals and their prevalence and distribution regardi...
Jung C, Gentil M, Müller E.The objective of the study was to investigate the age dependent occurrence of different infectious agents in foals with diarrhea. Methods: Fecal samples, which were submitted to a commercial laboratory for a PCR-profile "Foal Diarrhea Pathogens" from 01.01.2021 up to 31.12.2022 (n=144), were examined for Equine Coronavirus (ECoV), , (), toxin-encoding genes , , , and , toxin-encoding genes and , as well as Rotavirus A via PCR. Results: Pathogens could be detected in a high proportion (42.9%) of the samples. Rotavirus A was the most prevalent pathogen in the current study, followed by clos...
Axt CW, Springer A, von Luckner J, Naucke TJ, Müller E, Strube C, Schäfer I.Equine piroplasmosis (EP) is caused by (.) and (.) and is transmitted by hard ticks. Predominantly, the Mediterranean region is known as being endemic for both pathogens in Europe. However, autochthonous infections in central European countries such as Germany can no longer be ruled out due to individual case reports in horses without any stays abroad as well as the geographical expansion of the habitats of different tick species. The case reports presented underline the risk of infection for horses travelling to endemic areas and in horses imported from such areas to non-endemic countries...
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...
