Infectious diseases in horses encompass a range of illnesses caused by bacteria, viruses, fungi, or parasites. These diseases can affect various systems within the equine body, leading to symptoms that range from mild discomfort to severe systemic illness. Common infectious diseases in horses include equine influenza, strangles, equine herpesvirus, and West Nile virus. These diseases can be transmitted through direct contact with infected animals, contaminated surfaces, or vectors such as insects. Understanding the mechanisms of transmission, pathogenesis, and immune response is essential for effective prevention and control. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, diagnosis, treatment, and management of infectious diseases in horses.
Rozario C, Martínez-Sobrido L, McSorley HJ, Chauché C.Influenza A viruses (IAVs) are important respiratory pathogens of horses and humans. Infected individuals develop typical respiratory disorders associated with the death of airway epithelial cells (AECs) in infected areas. Virulence and risk of secondary bacterial infections vary among IAV strains. The IAV non-structural proteins, NS1, PB1-F2, and PA-X are important virulence factors controlling AEC death and host immune responses to viral and bacterial infection. Polymorphism in these proteins impacts their function. Evidence from human and mouse studies indicates that upon IAV infection, the...
Schwartz EJ, Costris-Vas C, Smith SR.Equine infectious anemia virus (EIAV) is a lentivirus similar to HIV that infects horses. Clinical and experimental studies demonstrating immune control of EIAV infection hold promise for efforts to produce an HIV vaccine. Antibody infusions have been shown to block both wild-type and mutant virus infection, but the mutant sometimes escapes. Using these data, we develop a mathematical model that describes the interactions between antibodies and both wild-type and mutant virus populations, in the context of continual virus mutation. The aim of this work is to determine whether repeated vaccinat...
Thomson P, Toro J, Lara F, Hernández D, Aros K, Valenzuela-Lopez N.We present the first case of rhinopharyngitis due to Aspergillus fumigatus in a purebred Chilean horse. Clinically, manifested mucopurulent discharge from both nostrils, inflammation of the nasal, ocular, and ear mucosa; associated with decay and hyporexia. Based on the clinical signs and analysis of the mycological and molecular transtracheal aspirate sample, the present case was diagnosed as Aspergillus fumigatus rhinopharyngitis. After the antifungal susceptibility test, oral itraconazole treatment was maintained for 45 days, showing no clinical sign.
Abbas G, Ghafar A, Hurley J, Bauquier J, Beasley A, Wilkes EJA, Jacobson C, El-Hage C, Cudmore L, Carrigan P, Tennent-Brown B, Gauci CG, Nielsen MK....Cyathostomins are the most important and common parasitic nematodes of horses, with > 50 species known to occur worldwide. The frequent and indiscriminate use of anthelmintics has resulted in the development of anthelmintic resistance (AR) in horse nematodes. In this study we assessed the efficacy of commonly used anthelmintics against cyathostomins in Australian thoroughbred horses. Methods: Two drug efficacy trials per farm were conducted on two thoroughbred horse farms in the state of Victoria, Australia. In the first trial, the horses on Farm A were treated with single and combinations ...
Breuil MF, Joseph M, Petry S.The gold standard method to isolate and identify Taylorella equigenitalis, the contagious agent of equine metritis, is the culture method according to the World Organisation for Animal Health Terrestrial Manual. No selective T. equigenitalis chocolate agar medium has been developed since the 1980s and the existing media show limited performances due to the fastidious nature of T. equigenitalis and the presence of interfering bacteria in the genital tract of equines. Here, the growth rates of 6 T. equigenitalis strains and 7 non-T. equigenitalis strains were compared on Timoney's selective medi...
Kinoshita Y, Kakoi H, Ishige T, Yamanaka T, Niwa H, Uchida-Fujii E, Nukada T, Ueno T.Taylorella equigenitalis causes contagious equine metritis. Here we compared seven nucleic acid amplification tests for T. equigenitalis to select a rapid and reliable diagnostic method. The 95% detection limits of each assay varied greatly: real-time PCR had the lowest detection limit (0.77 fg/reaction); those of some of the conventional PCRs (cPCRs) were >100 fg/reaction. In experimentally infected samples, real-time PCR and semi-nested PCR showed the highest positive numbers (33 out of 42 samples), but two of the cPCRs detected only 2 and 7 positive results. Our results indicate that the us...
El-Hage C, Mekuria Z, Dynon K, Hartley C, McBride K, Gilkerson J.Equine herpesviruses (EHVs) are common respiratory pathogens in horses; whilst the alphaherpesviruses are better understood, the clinical importance of the gammaherpesviruses remains undetermined. This study aimed to determine the prevalence of, and any association between, equine respiratory herpesviruses EHV1, -2, -4 and -5 infection in horses with and without clinical signs of respiratory disease. Nasal swabs were collected from 407 horses in Victoria and included clinically normal horses that had been screened for regulatory purposes. Samples were collected from horses during Australia's e...
Napp S, Llorente F, Beck C, Jose-Cunilleras E, Soler M, Pailler-García L, Amaral R, Aguilera-Sepúlveda P, Pifarré M, Molina-López R, Obón E....The surveillance for West Nile virus (WNV) in Catalonia (northeastern Spain) has consistently detected flaviviruses not identified as WNV. With the aim of characterizing the flaviviruses circulating in Catalonia, serum samples from birds and horses collected between 2010 and 2019 and positive by panflavivirus competition ELISA (cELISA) were analyzed by microneutralization test (MNT) against different flaviviruses. A third of the samples tested were inconclusive by MNT, highlighting the limitations of current diagnostic techniques. Our results evidenced the widespread circulation of flaviviruse...
Barr B, Nieman NM.Sepsis is a significant cause of morbidity and mortality in neonatal foals, especially during the first 7 days of life. Diagnosing sepsis in neonatal foals can be challenging because initial clinical signs are often ambiguous and non-specific. Objective: To determine if the major acute phase protein serum amyloid A (SAA) as measured by a point-of-care SAA testing device can be used as an evidence-based biomarker of sepsis. Methods: Retrospective cohort. Methods: Clinical diagnosis of sepsis based on positive bacterial blood culture or a positive sepsis score was obtained and compared to SAA v...
Page AE, Partridge E, Erol E, Scoggin KE, Fedorka CE, Ruby RE, Ball BA, Horohov DW, Adam E.Cases of nocardioform placentitis are characterized by focal, mucoid placentitis resulting in late-term abortion, premature birth, or small, full-term foals, occur sporadically, and are most commonly associated with Crossiella equi and Amycolatopsis spp. infection. The goal of this project was to develop an enzyme-linked immunosorbent assay (ELISA) for quantifying antibodies against Crossiella equi and Amycolatopsis spp. and utilize the ELISA to determine when exposure occurs. Serum samples collected during the 2020 foaling season from Crossiella equi (n = 8) and Amycolatopsis spp. (n = 32...
Ribeiro DSC, Martins AV, Lobão LF, Ribeiro MS, Palmer JPS, Corrêa LL, Uchôa CMA, da Silva S, Meireles MV, Amendoeira MRR, Barbosa ADS.An analysis was made of the frequency of Cryptosporidium spp. in fecal samples from horses raised on farms in the Teresópolis city, state of Rio de Janeiro, Brazil, and the risk factors that favored this infection. Between 2019 and 2020, 314 samples of equine feces were collected, 287 of which came from English Thoroughbred horses and 27 from ponies. Information on the horses and their management were retrieved from a stud book and forms filled out by trainers. The fecal samples were subjected to macroscopic analysis, modified Sheather's and Lutz parasitological techniques, safranin staining,...
Saini S, Singha H, Shanmugasundaram K, Tripathi BN.Burkholderia mallei causes a highly fatal infectious disease in equines known as glanders. It is one of the OIE listed notifiable diseases, which entails strict control policy measures once B. mallei infection is confirmed in the susceptible hosts. Humans, especially equine handlers, veterinary professionals and laboratory workers are at greater risk to acquire the B. mallei infection directly through prolonged contact with glanderous equines, and indirectly through unprotected handling of B. mallei contaminated materials. Further, natural resistance of B. mallei to multiple antibiotics, aeros...
Rahmani SS, Malekifard F, Tavassoli M.Neospora caninum is an Apicomplexan parasite that can cause enormous economic losses due to abortions in cattle. The present study investigated the role of Neospora spp. infection in equine abortion in Iranian donkeys using molecular and phylogenetic analyses. Twenty-nine-aborted fetuses and 29 blood samples from their dams were collected from six different regions in the West and Northwest of Iran. They were tested for N. caninum by PCR at the Nc5 locus, followed by sequencing of five of the PCR products. The overall molecular prevalence was 34.5% in blood samples and the prevalence by DNA de...
Nielsen MK, Doran D, Slusarewicz P.Fecal egg counts are essential monitoring tools in veterinary parasite control. In recent years, several groups have developed automated egg counting systems based on image analysis and deep learning algorithms. Work in our laboratory demonstrated that an automated system performed with significantly better precision than traditional egg counting techniques. However, while the counting process is no longer operator dependent, the pre-analytical homogenization steps still are. This study aimed at evaluating the influence of sample homogenization on diagnostic performance on an automated equine ...
Risso A, Campos G, Garcia H, Zerpa H.Equine piroplasmosis (EP) is a tick-borne infectious disease highly prevalent in tropical and subtropical regions, such as Venezuela. EP affects wild and domestic equids leading to several clinical presentations, from asymptomatic to severely affected animals. In this study, thirty-three (33) sport horses under regular training activities and from endemic regions of north-central Venezuela were submitted to an observational survey, case-control, to describe the presence of clinical signs and natural EP infections. A conventional PCR assay targeting the SSU rRNA gene revealed EP etiologic agent...
Liu CC, Hsiao YC, Chu LJ, Wang PJ, Liu CH, Hsieh WC, Yu JS., also known as Taiwanese cobra, is one of the most prevalent venomous snakes in Taiwan. Clinically, freeze-dried neurotoxic antivenom (FNAV) produced from horses by Taiwan Centers for Disease Control (CDC) has been the only approved treatment for envenoming for the last few decades. During antivenom production, large numbers of mice are used in the in vivo assay to determine whether the neutralization potency of hyperimmunized equines is satisfactory for large-scale harvesting. However, this in vivo assay is extremely laborious, expensive, and significantly impairs animal welfare. In the pre...
Lee SK, Park D, Lee I.Equine parvovirus-hepatitis (EqPV-H) causes equine hepatitis. The prevalence of EqPV-H in healthy horses has been reported in the United States, China, Germany, and Austria. The present study determined the prevalence of EqPV-H in the sera of clinically healthy horses in South Korea to identify the potential factors for infection and examine the genetic diversity of EqPV-H DNA sequences through comparison with foreign strains. Serum samples collected from 321 horses were tested for EqPV-H using non-structural protein 1 (NS1)-specific polymerase chain reaction. The associations of EqPV-H infect...
Suganuma K, Acosta TJ, Valinotti MFR, Sanchez AR, Mossaad E, Elata A, Inoue N.Despite the epidemic situation of animal trypanosomosis caused by Trypanosoma evansi, Trypanosoma equiperdum and Trypanosoma vivax in South American countries, there are no reports for the prevalence of animal trypanosomes in Paraguay. In this study, 408 blood samples were obtained from apparently healthy horses from sixteen departments of Paraguay, for routine medical check-up from August to September 2019, and a polymerase chain reaction (PCR)-based cross-sectional study was carried out to identify trypanosome prevalence. The prevalence of Trypanozoon (T. evansi and T. equiperdum) and T. viv...
Rodríguez N, Whitfield-Cargile CM, Chamoun-Emanuelli AM, Hildreth E, Jordan W, Coleman MC.The nasopharyngeal bacterial and fungal microbiota of normal horses and those with nasopharyngeal cicatrix syndrome (NCS) are unknown. Objective: To describe the microbiota from nasopharyngeal washes of healthy horses and of horses acutely affected with NCS. Methods: Twenty-six horses acutely affected with NCS horses and 14 unaffected horses. Methods: Prospective, observational cohort study. Horses were recruited by investigators through personal communications in central Texas. Bacterial (16s RNA) and fungal (internal transcribed spacer) microbiota from nasopharyngeal washes were evaluated. P...
Gómez-Cabrera K, Salas-Romero J, Sifontes JA, de la Torre Cánova R, Salas JE, Nielsen MK.For the past several decades, selective anthelmintic therapy (SAT) has been recommended in temperate climate countries for controlling gastrointestinal parasites in horses. However, the feasibility of this approach in tropical climates remains unknown, given the very different parasite transmission patterns and a larger representation of working equids. The aim of this study was to evaluate the bio-economic feasibility of SAT in horses kept under tropical conditions of Camagüey, Cuba. Fecal egg counts were determined from 794 adult horses and used for evaluating three different putative treat...
Kapdi A, Dhanze H, Sahu A, Singh V, Kumar MS, Bhilegaonkar KN, Gulati BR.Japanese encephalitis (JE) is a mosquito borne flaviviral zoonoses, causing fatal disease in equines and humans. JE is endemic in most of the states of India with occurrence of human cases every year. The horses are not vaccinated against JE in India and thus they are at more risk of acquiring the disease. Due to nonavailability of indigenously developed ELISA and high cost of imported kits, regular sero-surveillance is not being carried out to assess the true picture of JE virus in equine population of India. Therefore, a recombinant NS1 protein based indirect IgG ELISA was developed with the...
Tan LP, Mohd Rajdi NZI, Mohamad MA, Mohamed M, Hamdan RH, Goriman Khan MAK, Ahmad Syazwan S, Seng Hua L.Trypanosoma (Megatrypanum) theileri is a non-pathogenic or weakly pathogenic parasite of domestic cattle that is cyclically transmitted by blood-sucking insects, mainly tabanid flies. It has been reported in several countries like Brazil, Venezuela, Japan, Taiwan, Thailand, Vietnam, and the Philippines. Although the ruminant industry is actively expanded in Malaysia, T. theileri and T. theileri-like trypanosomes have never been reported from Malaysia. The low pathogenicity of this species might be the main reason for overlooking T. theileri in this country. This paper describes an unforeseen f...
Uzal FA, Arroyo LG, Navarro MA, Gomez DE, Asín J, Henderson E.Enteritis, colitis, and enterocolitis are considered some of the most common causes of disease and death in horses. Determining the etiology of these conditions is challenging, among other reasons because different causes produce similar clinical signs and lesions, and also because some agents of colitis can be present in the intestine of normal animals. We review here the main bacterial and viral causes of enterocolitis of horses, including Salmonella spp., Clostridium perfringens type A NetF-positive, C. perfringens type C, Clostridioides difficile, Clostridium piliforme, Paeniclostridium so...
Willette JA, Kopper JJ, Kogan CJ, Seguin MA, Schott HC.We investigated the effects of season and geographic location on detection of nucleic acids of potential enteric pathogens (PEPs) or their toxins (PEP-Ts) in feces of horses ≥6-mo-old in the United States. Results of 3,343 equine diarrhea PCR panels submitted to Idexx Laboratories for horses >6-mo-old were reviewed. Submission months were grouped into 4 seasons, and states were grouped into 4 geographic regions. Logistic regression was performed to assess effects of season and region on detection rates of PEPs and PEP-Ts. Agresti-Coull CIs were determined. Detection rate of was higher in...
Bosco-Lauth AM, Walker A, Guilbert L, Porter S, Hartwig A, McVicker E, Bielefeldt-Ohmann H, Bowen RA.We report pilot studies to evaluate the susceptibility of common domestic livestock (cattle, sheep, goat, alpaca, rabbit, and horse) to intranasal infection with SARS-CoV-2. None of the infected animals shed infectious virus via nasal, oral, or faecal routes, although viral RNA was detected in several animals. Further, neutralizing antibody titres were low or non-existent one month following infection. These results suggest that domestic livestock are unlikely to contribute to SARS-CoV-2 epidemiology.
Agerholm JS, Klas EM, Damborg P, Borel N, Pedersen HG, Christoffersen M. Loss of pregnancy in mares can have many different causes, including both infectious and non-infectious conditions. Extrapolation of findings from other studies is often uncertain as the significance of each cause varies across regions. Causes of pregnancy loss in mares have never been thoroughly studied in Denmark, so a prospective cross-sectional cohort study targeting the entire Danish population of pregnant mares was performed over a period of 13 months to obtain knowledge of the significance of individual causes. Fifty aborted or prematurely delivered stillborn fetuses were submitted for...
Peano A, Arnoldi S, Čmoková A, Hubka V.This article reports the first verified cases of infection by Trichophyton bullosum in Africa since the description of the fungus, isolated in 1933 from the coat of horses in Tunisia and Mali. We found the fungus in cutaneous samples obtained from donkeys suffering from severe dermatitis with areas of alopecia and scaling in the surroundings of Cairo (Egypt). Fungal elements (arthroconidia and hyphae) were seen at the microscopy of material collected by skin scraping and digested in NaOH. Fungal colonies grown on various culture media were identified through PCR and sequencing of the ITS rDNA ...
Prouillac C.Antibiotic resistance has become a major concern for not only human health, but also for animal health. To preserve the efficacy of antibiotics, it has become essential to establish measures to regulate the prescription of antibiotics to ensure their prudent use. In France, these measures have been translated into regulations for animal health since 2015, with the publication of three important regulatory texts. The results obtained on a national scale in terms of reducing the use of antibiotics have been satisfactory. The aim of our study was to evaluate the differences related to the prescri...
Yoon J, Park T, Kim A, Song H, Park BJ, Ahn HS, Go HJ, Kim DH, Lee JB, Park SY, Song CS, Lee SW, Choi IS.Equine parvovirus-cerebrospinal fluid (EqPV-CSF) and eqcopivirus (EqCoPV) are new parvovirus species (EqPVs) identified from various tissues (CSF, blood, and respiratory swabs) in horses with neurologic and respiratory diseases. In this study, we described the prevalence rate of EqPV-CSF and EqCoPV in 133 and 77 serum and fecal samples, respectively, using polymerase chain reaction. Further, we analyzed the potential risk factors for infection. We calculated the nucleotide and amino acid similarity and constructed phylogenetic trees. There was a moderate-to-high prevalence rate (EqPV-CSF: 3.8%...
Damiani AM, de Vries M, Reimers G, Winkler S, Osterrieder N.A particularly severe equine herpesvirus type 1 (EHV-1) abortion outbreak occurred at a breeding farm in northern Germany. Sixteen of 25 pregnant mares that had received regular vaccination using an inactivated vaccine aborted and two gave birth to weak non-viable foals in a span of three months, with 89% of cases occurring within 40 days after the initial abortion case. Virological examinations revealed the presence of EHV-1 in all cases of abortion and serological follow-up in mares confirmed recent infection. Molecular studies identified a neuropathogenic variant (Pol/ORF30 A2254 to G2254) ...
Stothart MR, Greuel RJ, Gavriliuc S, Henry A, Wilson AJ, McLoughlin PD, Poissant J.Studies of microbiome variation in wildlife often emphasize host physiology and diet as proximate selective pressures acting on host-associated microbiota. In contrast, microbial dispersal and ecological drift are more rarely considered. Using amplicon sequencing, we characterized the bacterial microbiome of adult female (n = 86) Sable Island horses (Nova Scotia, Canada) as part of a detailed individual-based study of this feral population. Using data on sampling date, horse location, age, parental status, and local habitat variables, we contrasted the ability of spatiotemporal, life history...
Schuler LA, Khaitsa ML, Dyer NW, Stoltenow CL.To characterize an outbreak of West Nile virus (WNV) infection in horses in North Dakota in 2002, evaluate vaccine effectiveness, and determine horse characteristics and clinical signs associated with infection. Methods: Retrospective study. Methods: 569 horses. Methods: Data were obtained from veterinary laboratory records, and a questionnaire was mailed to veterinarians of affected horses. Results: Affected horses were defined as horses with typical clinical signs and seroconversion or positive results of virus isolation; affected horses were detected in 52 of the 53 counties and concentrate...
Bamberg WM, Pape WJ, Beebe JL, Nevin-Woods C, Ray W, Maguire H, Nucci J, Massung RF, Gershman K.Coxiella burnetii is a bacterium located worldwide that can cause Q fever when inhaled. We describe an outbreak of Q fever associated with a horse-boarding ranch that had acquired two herds of goats. We conducted case finding and cohort studies among persons who boarded horses on the ranch and ranchers and among residents in the surrounding community, and conducted sampling of the goats and environment, to determine risk factors for infection and guide public health interventions. Sixty-six ranchers and persons who boarded horses on the ranch were interviewed; 62 (94%) were not professional ra...
Frazer ML.Lawsonia intracellularis is an emerging equine pathogen that is a cause of equine proliferative enteropathy (EPE). Objective: To describe the signalment, month of presentation, common clinical signs, clinicopathologic values, diagnostic tests used, antimicrobial use, and survival status in horses affected with EPE; to evaluate how affected horses sold at public auction as yearlings; and to determine results of fecal polymerase chain reaction (PCR) and serum immunoperoxidase monolayer assay (IPMA) results in age matched, clinically normal herdmates. Methods: The study group was 57 horses treate...
Tegtmeyer B, Echelmeyer J, Pfankuche VM, Puff C, Todt D, Fischer N, Durham A, Feige K, Baumgärtner W, Steinmann E, Cavalleri JV.Equine hepacivirus (EqHV) in equids represents the closest homologue to hepatitis C virus (HCV) infecting humans. A majority of HCV infected patients develop a chronic course of infection leading to liver fibrosis, cirrhosis and liver failure. However, in horses mostly transient mild subclinical infections are reported for EqHV to date. EqHV can be involved in chronic liver diseases of horses. Biochemical parameters in serum samples were measured. Viral load was determined using qPCR. Next generation sequencing (NGS) of serum was performed. Liver tissue was stained with haematoxylin and eosin ...
Gibson JS, Slater JD, Awan AR, Field HJ.Six specific pathogen-free foals shown to be free of equine herpesvirus-1 and 4 (EHV-1 and -4) and lacking in maternally-derived antibodies were used to investigate the pathogenesis of EHV-1 in horses. Following primary intranasal inoculation with EHV-1 all foals showed signs of a mild, self-limiting upper respiratory tract infection. A leucopenia was observed, comprising both a lymphopenia and neutropenia. Virus was isolated from nasal mucus and buffy coat cells over several days during the clinical episode and after the animals became clinically normal. Notwithstanding the mildness of the cl...
Reuter G, Maza N, Pankovics P, Boros A.Non-primate hepacivirus (NPHV) is a recently identified hepacivirus (family Flaviviridae) in dog and horse; however, the disease associations remain unknown. This study reports the detection of natural NPHV infection in a horse with apparent hepatitis, liver damage and high-level viraemia. NPHV could be hepatotropic and associated with hepatitis in horses.
Ross PF, Rice LG, Reagor JC, Osweiler GD, Wilson TM, Nelson HA, Owens DL, Plattner RD, Harlin KA, Richard JL.During the fall of 1989 and winter of 1990, numerous reports of equine leukoencephalomalacia (ELEM) occurred from many regions of the United States. Typically, horses were consuming feed partially or entirely composed of corn and/or corn screenings. From October 1989 through May 1990, samples from 55 confirmed or suspected ELEM cases were received at the National Veterinary Services Laboratories, Ames, Iowa, for fumonisin B1 analysis. Samples from 9 cases in 1984-1985 were also obtained. Fumonisin B1, a mycotoxin produced by Fusarium moniliforme, causes ELEM, but little is known of naturally o...
Payne S, Parekh B, Montelaro RC, Issel CJ.The unique periodic nature of equine infectious anaemia (EIA) is believed to result from the ability of the infecting virus. EIAV, to undergo relatively rapid antigenic variations which circumvent host immune responses resulting in distinct virus populations in sequential clinical episodes in the persistently infected horse. This model was examined by oligonucleotide mapping comparisons of the RNA genomes of selected isolates of EIAV. Variations in oligonucleotide maps could be reproducibly demonstrated (i) after adaptation of the laboratory strain of EIAV to replication in a pony, (ii) after ...
Gokbulut C, McKellar QA.Internal parasites of horses comprise an intractable problem conferring disease, production and performance losses. Parasitism can rarely be controlled in grazing horses by management alone and anthelmintic drugs have formed the basis of therapy and prophylaxis for the last sixty years. The pharmacology of the anthelmintic drugs available dictate their spectrum of activity and degree of efficacy, their optimal routes of administration and characteristics which prevent some routes of administration, their safety tolerance and potential toxicities and as a consequence of their persistence in the...
Battsetseg B, Xuan X, Ikadai H, Bautista JL, Byambaa B, Boldbaatar D, Battur B, Battsetseg G, Batsukh Z, Igarashi I, Nagasawa H, Mikami T, Fujisaki K.Ticks play an important role in human and veterinary medicine particularly due to their ability to transmit protozoan pathogens. In this study we have demonstrated that polymerase chain reaction (PCR) and nested PCR methods enabled detection of Babesia caballi and Babesia equi in field isolates of Dermacentor nuttalli adult ticks from Mongolia. Primers specific for 218 bp fragment merozoite antigen 1 (EMA-1) gene of B. equi successfully amplified products from all samples of D. nuttalli adult ticks while primers for the 430 bp fragment product from BC48 gene of B. caballi amplified products fr...
Torfason EG, Thorsteinsdóttir L, Torsteinsdóttir S, Svansson V.The horse population in Iceland is a special breed, isolated from other horses for at least 1000 years. This provides an exceptional opportunity to investigate old and new pathogens in an inbred herd with few infectious diseases. We have developed a high sensitivity semi-nested PCR to study equid gammaherpesviruses 2 and 5 (EHV-2 and 5) in Iceland. The first PCR is group specific, the second type-specific, targeting a 113bp sequence in the glyB gene. DNA isolated from white blood cells and 18 different organs was tested for the presence of EHV-2 and 5. This was done in adult horses and foals, ...
Bork S, Yokoyama N, Matsuo T, Claveria FG, Fujisaki K, Igarashi I.We evaluated the growth inhibitory effect of triclosan, which has recently been reported to inhibit the growth of Plasmodium species and Toxoplasma gondii, on bovine and equine Babesia parasites in in vitro cultures The growth of Babesia bovis and B. bigemina was significantly inhibited in the presence of 100 microg/ml of triclosan, while B. caballi and B. equi were susceptible to as low as 50 microg/ml. Babesia bigemina and B. caballi were completely cleared as early as on the first and second day of the treatment, respectively. These parasites did not exhibit any growth in the subsequent fiv...
Lindahl S, Båverud V, Egenvall A, Aspán A, Pringle J.Strangles is a contagious equine-specific disease caused by Streptococcus equi subsp. equi. Unfortunately, detection of S. equi can fail in up to 40% of horses with strangles. Whereas recent molecular biologic methods and sampling techniques have improved recovery of S. equi optimal sampling methods and laboratory analyses remain ill-defined. Objective: To determine the yield of S. equi from horses with acute strangles in confirmed outbreaks by field-sampling methods subjected to culture and biochemical identification, and real-time PCR directly and after culture. Methods: Fifty-seven horses o...
Lester HE, Matthews JB.Equine gastrointestinal nematodes are ubiquitous; in horses that graze contaminated pasture and that are not treated appropriately, large numbers of worms can accumulate, which can lead to serious clinical disease. Nematode control has traditionally followed interval treatment regimens, which involve regular anthelmintic administration to all horses based on the strongyle egg reappearance periods of each drug, usually defined around the time of licensing. Interval treatment programmes have resulted in substantial reductions in large strongyle disease, but have made major contributions to the d...
Tajima M, Nakajima H, Ito Y.Equine infectious anemia (EIA) virus was observed in thin sections of infected cultured horse leukocytes by electron microscopy. The virus particles had a spherical shape and were between 80 and 120 nm in diameter. Most of them contained an electron-dense nucleoid 40 to 60 nm in diameter. They were observed to form by a process of budding from the plasma membrane and appeared to have thin surface projections. The particles described were not detected in uninfected cultured cells, and their appearance could be prevented by adding EIA immune serum to the inoculum. The implications of these findi...
Thomson GR, Mumford JA, Campbell J, Griffiths L, Clapham P.An investigation was made of 3 serological tests (virus neutralization, complement fixation and indirect immunofluorescence), which are applicable to epidemiological studies of infections by Equid herpesvirus 1 (EHV-1). Sera from gnotobiotic foals inoculated intranasally with various strains of EHV-1 were unable in some cases to neutralize heterologous strains and these results were not consistent with the existence of clearly-defined subtypes of EHV-1, as previously proposed. The cross-reactions in complement-fixation tests paralleled those with neutralization but immunofluorescence tests wer...
Dennis SJ, Meyers AE, Guthrie AJ, Hitzeroth II, Rybicki EP.African horse sickness (AHS) is a debilitating and often fatal viral disease affecting horses in much of Africa, caused by the dsRNA orbivirus African horse sickness virus (AHSV). Vaccination remains the single most effective weapon in combatting AHS, as there is no treatment for the disease apart from good animal husbandry. However, the only commercially available vaccine is a live-attenuated version of the virus (LAV). The threat of outbreaks of the disease outside its endemic region and the fact that the LAV is not licensed for use elsewhere in the world, have spurred attempts to develop an...
Dietz WH, Peralta PH, Johnson KM.The clinical and laboratory findings in ten humans infected with Venezuelan equine encephalitis virus, subtype I-D, are described in this report. Clinical and laboratory data indicate that, in contrast to equine infections, human infection with these enzootic virus strains (I-D) is similar to human infection with epizootic strains (I-ABC). In most cases there was an abrupt onset of fever, muscle pain, and vomiting. Virus was recovered from sera obtained during the first 3 days of illness. Lymphopenia occurred in all patients, and neutropenia occurred in three. No sequelae of these infections w...
Chirnside ED, de Vries AA, Mumford JA, Rottier PJ.Complementary DNAs encoding ORFs 2 to 7 equine arteritis virus (EAV) have been cloned into the expression vector pGEX to produce glutathione-S-transferase fusion proteins. Recombinant proteins were affinity purified and screened in ELISA with equine sera to identify immunoreactive polypeptides. The large envelope glycoprotein (GL) was identified as the most reactive to EAV-positive equine sera and an immuno-dominant epitope was mapped between amino acids 55 and 98 by subcloning and expression. A fusion protein covering this region and a GL-specific synthetic peptide (residues 75 through 97) in...
O'Rourke JP, Newbound GC, Kohn DB, Olsen JC, Bunnell BA.This report compares gene transfer efficiencies as well as durations and levels of gene expression for human immunodeficiency virus (HIV) and equine infectious anemia virus (EIAV) lentiviral vectors in a variety of human cell types in vitro. EIAV and HIV vectors transduced equivalent numbers of proliferating and G1/S- and G2/M-arrested cells, and both had very low efficiencies of transduction into G0-arrested cells. Analysis of the levels of both the enhanced green fluorescent protein (EGFP) and mRNA demonstrated that the HIV-transduced cells expressed greater levels of EGFP protein and RNA th...
Álvarez-Narváez S, Giguère S, Cohen N, Slovis N, Vázquez-Boland JA.Multidrug resistance has been detected in the animal and zoonotic human pathogen Rhodococcus equi after mass macrolide/rifampin antibioprophylaxis in endemically affected equine farms in the United States. Multidrug-resistant (MDR) R. equi emerged upon acquisition of pRERm46, a conjugative plasmid conferring resistance to macrolides, lincosamides, streptogramins, and, as we describe, tetracycline. Phylogenomic analyses indicate that the increasing prevalence of MDR R. equi since it was first documented in 2002 is caused by a clone, R. equi 2287, attributable to coselection of pRErm46 with a ch...
Hollis AR, Wilkins PA, Palmer JE, Boston RC.Bacteremia in sick foals is associated with survival, but the association of bacteremia and diarrhea is not reported. Objective: Neonatal foals with diarrhea will commonly be bacteremic. Methods: One hundred and thirty-three neonatal foals. Methods: Records of all foals <30 days of age presenting with diarrhea between January 1990 and September 2007 were reviewed. Results: Sixty-six of 133 foals (50%) were bacteremic at admission, with 75 isolates from the 66 samples. The blood culture from a further 18 foals (13.5%) grew coryneform bacteria. Nine foals (6.8%) had 2 or more organisms grown on ...
Saiz JC.West Nile virus (WNV) is a widely distributed enveloped flavivirus transmitted by mosquitoes, which main hosts are birds. The virus sporadically infects equids and humans with serious economic and health consequences, as infected individuals can develop a severe neuroinvasive disease that can even lead to death. Nowadays, no WNV-specific therapy is available and vaccines are only licensed for use in horses but not for humans. While several methodologies for WNV vaccine development have been successfully applied and have contributed to significantly reducing its incidence in horses in the US, n...
Campos RK, Brum MC, Nogueira CE, Drumond BP, Alves PA, Siqueira-Lima L, Assis FL, Trindade GS, Bonjardim CA, Ferreira PC, Weiblen R, Flores EF....During the last bovine vaccinia (BV) outbreaks, several Vaccinia virus (VACV) strains were isolated and characterised, revealing significant polymorphisms between strains, even within conserved genes. Although the epidemiology of VACV has been studied in BV outbreaks, there is little data about the circulation of the Brazilian VACV isolates. This study describes the genetic and biological characterisation of two VACV isolates, Pelotas 1 virus (P1V) and Pelotas 2 virus (P2V), which were obtained concomitantly from a horse affected by severe cutaneous disease. Despite being isolated from the sam...
Cheadle MA, Tanhauser SM, Dame JB, Sellon DC, Hines M, Ginn PE, MacKay RJ, Greiner EC.The nine-banded armadillo (Dasypus novemcinctus) is an intermediate host of at least three species of Sarcocystis, Sarcocystis dasypi, Sarcocystis diminuta, and an unidentified species; however, life cycles of these species have not been determined. Following feeding of armadillo muscles containing sarcocysts to the Virginia opossum (Didelphis virginiana), the opossums shed sporulated Sarcocystis sporocysts in their faeces. Mean dimensions for sporocysts were 11.0x7.5 microm and each contained four sporozoites and a residual body. Sporocysts were identified as Sarcocystis neurona using PCR and...
Laperriere V, Brugger K, Rubel F.The West Nile virus (WNV) is an arthropod-borne virus (arbovirus) circulating in a natural transmission cycle between mosquitoes (enzootic vectors) and birds (amplifying hosts). Additionally, mainly horses and humans (dead-end hosts) may be infected by blood-feeding mosquitoes (bridge vectors). We developed an epidemic model for the simulation of the WNV dynamics of birds, horses and humans in the U.S., which we apply to the Minneapolis metropolitan area (Minnesota). The SEIR-type model comprises a total of 19 compartments, that are 4 compartments for mosquitoes and 5 compartments or health st...
Franzén P, Aspan A, Egenvall A, Gunnarsson A, Karlstam E, Pringle J.Anaplasma phagocytophilum infects several mammalian species, and can persist in sheep, dogs, and calves. However, whether this organism persists in horses or induces long-term clinical abnormalities is not known. Objective: To evaluate whether A. phagocytophilum can persist in horses and to document clinical findings for 3 months after complete recovery from acute disease. Methods: Five clinically normal adult horses that had recovered spontaneously from experimentally induced acute disease caused by a Swedish equine isolate of A. phagocytophilum. Methods: Horses were monitored for up to 129 d...
Björnsdóttir S, Harris SR, Svansson V, Gunnarsson E, Sigurðardóttir ÓG, Gammeljord K, Steward KF, Newton JR, Robinson C, Charbonneau ARL....Iceland is free of the major infectious diseases of horses. However, in 2010 an epidemic of respiratory disease of unknown cause spread through the country's native horse population of 77,000. Microbiological investigations ruled out known viral agents but identified the opportunistic pathogen subsp. () in diseased animals. We sequenced the genomes of 257 isolates of to differentiate epidemic from endemic strains. We found that although multiple endemic clones of were present, one particular clone, sequence type 209 (ST209), was likely to have been responsible for the epidemic. Concurrent ...
