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.
Todd EW.Antiproteinase sera were prepared by immunizing horses with filtrates from a selected strain of group A streptococcus. This strain, which produced high titred proteinase but no erythrogenic toxin, was selected from forty-two strains of group A streptococci which produced varying amounts of proteinase. A few strains belonging to groups B, C, and G were also tested; they were all proteinase-negative. Methods are described for titrating streptococcal proteinase in crude culture filtrates and for measuring the antiproteinase activity of serum. The antiproteinase titres of sera from immunized horse...
With outbreaks of equine influenza continuing to be reported in the UK, Richard Newton and Fleur Whitlock of the Animal Health Trust discusses practical steps that vets can promote and practise to reduce the risk of the virus spreading.
Romi R, Pontuale G, CIufolini MG, Fiorentini G, Marchi A, Nicoletti L, Cocchi M, Tamburro A.In the late summer of 1998, an outbreak of equine encephalomyelitis due to West Nile virus (WNV) occurred in the Tuscany region of central Italy. The disease was detected in 14 race horses from nine localities in four Provinces: Firenze, Lucca, Pisa and Pistoia. The outbreak area included Fucecchio wetlands (1800 ha), the largest inland marsh in Italy, and the adjacent hilly Cerbaie woodlands with farms breeding horses. To detect potential vectors of WNV, entomological surveys of Fucecchio and Cerbaie were undertaken during 1999-2002 by collecting mosquito larvae from breeding sites and adult ...
Stadejek T, Mittelholzer Ch, Oleksiewicz MB, Paweska J, Belák S.Equine arteritis virus (EAV) was detected by RT-nested PCR in semen samples from a naturally infected South African donkey. Sequence analysis of the amplified ORF5 fragment revealed only 60 to 70% nucleotide identity to a panel of EAV reference sequences. The unique donkey EAV sequence was also found to be stable during passage in horses. The sequence data reported in this study indicate that the South African donkey variant might represent a new genotype of EAV. The distinct genetic properties of the South African asinine strain of EAV suggest a divergent evolution of this arterivirus in vari...
Bezerra CS, Cargnelutti JF, Sauthier JT, Weiblen R, Flores EF, Alves CJ, Clementino IJ, Santos CSAB, Azevedo SS.The aim of this survey was to estimate the apparent herd-level and animal-level prevalences, as well as to identify risk factors and spatial clustering of vesicular stomatitis virus (VSV) positive herds in the state of Paraíba, semiarid of Brazil. The state was divided into three sampling strata: Sertão, Borborema and Zona da Mata/Agreste. For each sampling stratum, herd-level and animal-level prevalences were estimated by a two-stage sampling survey. First, a pre-established number of herds (primary sampling units) were randomly selected; second, within each herd, a pre-established number o...
Schmitt S, Stephan R, Huebschke E, Schaefle D, Merz A, Johler S.Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of severe infections in humans and animals worldwide. Studies elucidating the population structure, staphylococcal cassette chromosome mec types, resistance phenotypes, and virulence gene profiles of animal-associated MRSA are needed to understand spread and transmission. Objective: The objective of this study was to determine 1) clonal complexes and spa types, 2) resistance phenotypes, and 3) virulence/resistance gene profiles of MRSA isolated from animals in Switzerland. Methods: We analyzed 31 presumptive MRSA isolates co...
Gomez DE, Wong D, MacNicol J, Dembek K.The fecal bacterial microbiota of normal foals and foals with enterocolitis has been characterized using next-generation sequencing technology; however, there are no reports investigating the gut microbiota in foals hospitalized for other perinatal diseases. Objective: To describe and compare the fecal bacterial microbiota in healthy and sick foals using next-generation sequencing techniques. Methods: Hospitalized (17) and healthy foals (21). Methods: Case-control study. Fecal samples were collected from healthy and sick foals on admission. Sick foals were further divided into sick nonseptic (...
Middleton DJ, Weingartl HM.Hendra virus (HeV) and Nipah virus (NiV) form a separate genus Henipavirus within the family Paramyxoviridae, and are classified as biosafety level 4 pathogens due to their high case fatality rate following human infection and because of the lack of effective vaccines or therapy. Both viruses emerged from their natural reservoir during the last decade of the twentieth century, causing severe disease in humans, horses and swine, and infecting a number of other mammalian species. The current review summarizes our up to date understanding of pathology and pathogenesis in the natural reservoir spe...
Porphyre T, Grewar JD.African horse sickness (AHS) is a disease of equids that results in a non-tariff barrier to the trade of live equids from affected countries. AHS is endemic in South Africa except for a controlled area in the Western Cape Province (WCP) where sporadic outbreaks have occurred in the past 2 decades. There is potential that the presence of zebra populations, thought to be the natural reservoir hosts for AHS, in the WCP could maintain AHS virus circulation in the area and act as a year-round source of infection for horses. However, it remains unclear whether the epidemiology or the ecological cond...
Tanaka Y, Suganuma K, Watanabe K, Kobayashi Y.Dourine, caused by infection with Trypanosoma equiperdum, is one of the trypanosomiasis in equids. The clinical course of dourine is long-term, ranging from 1-2 months to several years. Since the pathogenesis of dourine has not yet been elucidated, experimental studies using mouse infection models are needed. Although mice are not susceptible to most T. equiperdum strains, some strains can infect mice. Even in such strains, infected mice develop rapidly transient parasitemia and die within 2-8 days. Therefore, mice experimentally infected with these T. equiperdum strains are not suitable for m...
Seyedmousavi S, Guillot J, Arné P, de Hoog GS, Mouton JW, Melchers WJ, Verweij PE.The importance of aspergillosis in humans and various animal species has increased over the last decades. Aspergillus species are found worldwide in humans and in almost all domestic animals and birds as well as in many wild species, causing a wide range of diseases from localized infections to fatal disseminated diseases, as well as allergic responses to inhaled conidia. Some prevalent forms of animal aspergillosis are invasive fatal infections in sea fan corals, stonebrood mummification in honey bees, pulmonary and air sac infection in birds, mycotic abortion and mammary gland infections in ...
Kalemkerian PB, Metz GE, Peral-García P, Lopez-Gappa J, Echeverría MG, Giovambattista G, Díaz S.We investigated the association of equine arteritis virus (EAV) infection and three short tandem repeat (STR) polymorphisms located within or in close proximity to equine lymphocyte antigen (ELA) region. We used a case-control design as a first approach before proceeding to select candidate genes. One hundred and sixty-five Silla Argentino horses were taken in 2002 from positive serological detections of EAV in Argentina, to determine whether STR genotypes were correlated to genetic susceptibility to EVA. Allele frequency distribution did not show significant differences between both groups (P...
Nichani AK, Sharma RD, Sarup S.Efficacy of medium RPMI-1640 (supplied by Gibco USA, Centron and Hi-media) supplemented with horse, donkey, sheep and goat sera was evaluated for in vitro propagation of Theileria annulata (Hisar) infected bovine mononuclear cells. The results were compared with the growth rate in RPMI-1640 supplemented with foetal bovine serum (Gibco). RPMI-1640 (Gibco) proved to be the best medium for in vitro cultivation of the parasite infected cells. Foetal bovine serum could be easily, safely and reliably substituted with goat and sheep sera in the growth medium. Horse and donkey sera also gave comparabl...
Wollstein M.The parameningococci of Dopter are culturally indistinguishable from true or normal meningococci, but serologically they exhibit differences as regards agglutination, opsonization, and complement deviation. Because of the variations and irregularities of serum reactions existing among otherwise normal strains of meningococci it does not seem either possible or desirable to separate the parameningococci into a strictly definite class. It appears desirable to consider them as constituting a special strain among meningococci not, however, wholly consistent in itself. The distinctions in serum rea...
Fairbanks EL, Baylis M, Daly JM, Tildesley MJ.African horse sickness virus (AHSV) is a vector-borne virus spread by midges (Culicoides spp.). The virus causes African horse sickness (AHS) disease in some species of equid. AHS is endemic in parts of Africa, previously emerged in Europe and in 2020 caused outbreaks for the first time in parts of Eastern Asia. Here we analyse a unique historic dataset from the 1989-1991 emergence of AHS in Morocco in a naïve population of equids. Sequential Monte Carlo and Markov chain Monte Carlo techniques are used to estimate parameters for a spatial-temporal model using a transmission kernel. These para...
Borchers K, Frölich K, Ludwig H.In blood samples of seven captive equid species from four German zoos EHV-1 specific antibodies were detected in 76% and EHV-4 specific antibodies in 73% of the 55 animals, whereas 93% were tested positive for EHV-2 and EHV-5, respectively. In only one blood sample from a Przewalski's wild horse EHV-4 DNA was amplified by PCR. From seven Przewalski's wild horses EHV-2, and from another one EHV-5 was isolated by cocultivation. The identity of the virus isolates was verified by PCR and restriction enzyme digestion.
Brees DJ, Sondhoff AH, Kluge JP, Andreasen CB, Brown CM.A 7-month-old foal was admitted to the hospital with a history of lethargy, weight loss, mild diarrhea, and anorexia. A diagnosis of proliferative enteritis caused by Lawsonia intracellularis-like organisms was made after necropsy and histologic examination of the small intestine. Although infection with L intracellularis-like organisms is a rare cause of enteritis in foals, it should be considered in the differential diagnosis, especially if the foal was housed in the proximity of pigs or pig feces. Antemortem diagnosis remains challenging because isolation of the organism in fecal material r...
Nakayama H, Shiga T, Uchida K, Chambers JK, Morino T, Sasaki N.There is no nationwide necropsy database of animals in Japan, and most of the records are available from the postwar period. To clarify the chronological transition of animal necropsy cases in Tokyo, Japan, the records accumulated in The University of Tokyo from 1902 were investigated. Of necropsy records on paper or electronic from 1902 to 2021 kept at the Laboratory of Veterinary Pathology, The University of Tokyo, totally 3,137 cases including 572 in 1903-1914 (the Meiji-Taisho period), 1,258 in 1956-1969 (the Showa period) and 1,307 in 2006-2020 (the Heisei-Reiwa period), respectively, wer...
Scott Weese J.Antimicrobial resistance (AMR) is an emerging problem in companion animals, because of difficult-to-treat infections, possible pressure to use antimicrobials that are important in human medicine, and potential zoonotic transmission. The extent and importance of AMR in companion animals are poorly understood, in part because of limited surveillance; however, it is clear that resistance is problematic in many pathogens and commensals, including staphylococci, enterococci, Escherichia coli and Salmonella.
Marquardt J, Heymer J, Heinz H, Adolf GR, Deegen E.Recombinant equine interferon-beta 1 (reqIFN-beta 1) induces an antiviral state in blood mononuclear cells (BMC) of horses. Maximal protection against replication of vesicular stomatitis virus is achieved 6 hours after treatment with IFN in vitro and in vivo. Duration of the protective effect depends on the dose of IFN in vitro and in vivo. Availability of reqIFN-beta 1 in cultures of BMC for up to 48 hours does not prolong the antiviral state. The protective effect on BMC after treatment with IFN has similar duration in vivo and in vitro. Monitoring of the effect of IFN in vivo is, thus, simp...
Corapi WV, Birch SM, Carlson KL, Chaffin MK, Snowden KF.CASE DESCRIPTION-A 22-year-old American Paint Horse gelding from the Gulf Coast region of Texas was evaluated for regrowth of a perirectal squamous cell carcinoma that had been surgically removed 11 months previously. CLINICAL FINDINGS-A necrotic and ulcerated mass was present below the anus. The horse had paraphimosis and was having difficulty with urination. Histologic examination of the mass revealed that it was squamous cell carcinoma, and the horse was euthanized because of the unlikelihood that the mass could be adequately resected and its close proximity to the urethra. OUTCOME-At necro...
Aref S.A study of the migration of fourth stage larvae of the parasite Strongylus vulgaris in the intestinal arteries of the horse is presented. It is established, that the larvae migrate along the arteries in almost straight lines. It is suggested that this is primarily due to their ability to sense the curvature of the vessel wall, and not, as might have been expected, because of an ability to sense the direction of blood flow. A larva will sometimes alter its direction of motion when encountering a small off-branching artery. This behaviour suggests, that the migration of S. vulgaris larvae can be...
Velineni S, DeNegri R, Artiushin SC, Timoney JF.Streptococcus zooepidemicus (Sz) and its clonal derivative Streptococcus equi (Se) share greater than 96% DNA identity and elicit immune responses to many shared proteins. Identification of proteins uniquely targeted by the immune response to each infection would have diagnostic value. Objective: The aim of the study was to compare serum antibody responses of horses infected by Se or Sz. Methods: Antibody levels were measured to panels of recombinant proteins of Sz and Se in sera of horses and ponies before and after experimental and naturally occurring invasive infections by these organisms. ...
Watson ED.The mechanisms that permit maternal tolerance of the conceptus allograft during early pregnancy in the mare have not been investigated. Embryos and endometria were collected from mares 14 days after ovulation and cultured for 20.5 h. The effect of addition of culture supernatant on incorporation of [3H]thymidine by equine peripheral blood lymphocytes was studied. Culture supernatant from endometrium of nonpregnant mares did not affect lymphocyte blastogenesis, but supernatant from both embryos and endometrium of pregnant mares reduced concanavalin A (Con A)- and phytohemagglutinin-induced blas...
Kudrimoti S, Machin J, Arojojoye AS, Awuah SG, Eisenberg R, Fenger C, Maylin G, Lehner AF, Tobin T.Based on structural similarities and equine administration experiments, Barbarin, 5-phenyl-2-oxazolidinethione from Brassicaceae plants, is a possible source of equine urinary identifications of aminorex, (R,S)-5-phenyl-4,5-dihydro-1,3-oxazol-2-amine, an amphetamine-related US Drug Enforcement Administration (DEA) controlled substance considered illegal in sport horses. We now report the synthesis and certification of d -barbarin to facilitate research on the relationship between plant barbarin and such aminorex identifications. D -barbarin synthesis commenced with production of d -2-oxo-2-phe...
Boussetta M, Chabchoub A, Ghram A, Jomaa I, Ghorbel A, Aouina T, Ben Amor H.Using the haemagglutination inhibition and immunodiffusion tests, a national serological survey was carried out to detect antibodies to equine influenza (EI) (A/equi/1/Prague 56 and A/equi/2/Miami 63) and equine infectious anaemia (EIA) in horse sera collected in northeastern Tunisia. 533 samples were analysed for EIA antibodies. All were negative. 13.6% of 433 equine sera tested for EI antibodies were positive. These results are discussed and compared with others obtained in Tunisia and bordering countries.
Tåmová B, Stumpa A, Zakopal J, Vĕzníková D, Mensík J.Equine influenza occurred in Czechoslovakia 14 years after the last epizootic in horses that had returned from abroad. Six strains A (Heq1Neq1) antigenically related to, but not identical with, strain A/eq/Praha/56 were isolated from 10 washings. Seroconversion was demonstrated with paired sera, but the antibody increase was more marked against the newly isolated strain.
Ramsauer AS, Badenhorst M, Cavalleri JV.Equine parvovirus hepatitis (EqPV-H) was first described in 2018 in a fatal case of Theiler's disease which followed the administration of an equine-origin biological product. The virus has since been frequently identified in serum and liver tissue of horses affected by Theiler's disease-an acute, severe hepatitis characterised by fulminant hepatic necrosis with a fatal outcome in most cases. EqPV-H is hepatotropic, appears to be associated with subclinical to severe hepatitis in horses, and is a likely cause of Theiler's disease. Although this disease is most frequently reported following the...
