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.
Jacob RJ, Price R, Bouchey D, Davis T, Borchelt J.This article reviews the findings on temperature sensitivity of equine herpesvirus isolates with an emphasis on equine herpesvirus 3, etiological agent of equine coital exanthema. The hypothesis is presented that the relative apathogenic nature of this herpesvirus may be an indirect result of its inability to synthesize and/or process glycoproteins needed by the virus to produce infectious virions at the normal body temperature of its natural host. It is suggested that equine herpesvirus 3 is the more evolved and naturally attenuated member of the equine herpesviruses.
Lopes CA, Moreno G, Curi PR.The susceptibilities of 760 Staphylococcus aureus strains isolated from animal infections (400), human infections (300) and healthy human carriers (60) to seven antibiotics were determined by an agar dilution technique. The isolates from human infections were more resistant to a wider spectrum of antibiotics than were the strains from animal infections and healthy human carriers. Amikacin and gentamicin were the most active drugs against all groups of strains.
Rwambo PM, Issel CJ, Adams WV, Hussain KA, Miller M, Montelaro RC.Three ponies were inoculated with plasma containing 10(4.8) TCID50 of equine infectious anemia virus (EIAV) and observed for 165 to 440 days. Each pony developed a febrile response within 3 weeks of infection during which a plasma viremia greater than or equal to 10(3.5) TCID50/ml was observed. Analyses of four isolates from sequential febrile episodes in a single pony were conducted by two-dimensional tryptic peptide maps and with monoclonal antibodies in immunoblots. Structural and antigenic alterations were observed in the envelope glycoproteins gp90 and gp45, with greatest variation in gp9...
Rwambo PM, Issel CJ, Hussain KA, Montelaro RC.A neutralization escape mutant (A/1 E) of equine infectious anemia virus was isolated after 13 passages in cell culture in the presence of serum containing antibodies to type- and group-specific determinants of EIAV envelope glycoproteins. Loss of neutralization by the selecting serum correlated with loss of two epitopes in the major envelope glycoprotein gp90 of A/1 E which were present in a parallel variant isolated from a persistently infected pony.
McGuire TC, O'Rourke KI, Perryman LE.Virus replication and subsequent viremia are clearly correlated with clinical disease in EIAV infected horses. Termination of viremia is the result of specific immune responses. Recurrences of viremia are associated with antigenic variation of neutralization-sensitive epitopes. Immunosuppression experiments indicate that the eventual control of EIAV and development of carriers is mediated by the immune system. Even though the immune response to EIAV has a protective effect, immune responses also cause some of the lesions. At least one part of the anemia, erythrocyte destruction, is caused by t...
Olaleye OD, Omilabu SA, Baba SS, Fagbami AH.Sera from horses and pigs obtained from Lagos and Ibadan respectively were examined for haemagglutination-inhibiting (HI) antibodies to two strains each of H3N2 and H1N1 subtypes of influenza A virus. More horse sera had HI antibodies to the H3N2 than the H1N1 strains while pig sera reacted almost equally with strains of both subtypes. All the horse sera had HI antibodies to the two strains of H3N2 subtype (A/Mississippi/1/85 and A/Leningrad/360/86), while 87% and 14% of the horses examined were positive to A/Taiwan/1/86 and A/Chile/1/83. On the other hand HI antibody prevalence to the two sub...
Aguilar CM, Rangel EF, Garcia L, Fernandez E, Momen H, Grimaldi Filho G, De Vargas Z.After outbreaks of cutaneous leishmaniasis in Solano State, Venezuela, 5% of the population had parasitized ulcers while after similar outbreaks in Mesquita, Rio de Janeiro State, Brazil, 9% had the disease. In these foci children, including some under six years of age, were affected. There was no significant difference in the occurrence of the disease according to sex or type of employment. In Solano, 3% of dogs and 28% of donkeys had parasitized lesions, while in Mesquita these indices were 19.8% and 30.8% respectively. The parasite from man, dogs and equines was identified as Leishmania (Vi...
Evermann JF.Retroviral infections of livestock have become of increasing importance due to their usefulness as comparative models for human retroviral infections and their effects upon animal health and marketability of animals and animal products nationally and internationally. This paper presents a perspective on the retroviruses of economic concern in veterinary medicine with emphasis on the importance of understanding the modes of virus transmission and the species specificity of the viruses. The retroviruses reviewed include the oncovirus, bovine leukosis virus, and the lentiviruses, equine infectiou...
Issel CJ, McManus JM, Hagius SD, Foil LD, Adams WV, Montelaro RC.Equine infectious anemia has been managed in most countries by the imposition of testing and quarantine regulations. In the United States, about 700,000 of the more than 7,000,000 horses are tested annually. As long as the status of greater than 90% of the horse population remains unknown and horses are transported and congregate in a relatively unrestricted manner, EIA will continue to exact its toll. Therefore, it is incumbent on the scientific community to continue to develop and refine practical and sensitive diagnostic tests for EIA which will be used in an expanding market, to reduce the...
Uggla A, Mattson S, Juntti N.Samples of serum or plasma taken during 1986 and 1987 from 244 pet cats, 303 dogs and 219 horses, randomly selected among animals referred to the Animal Clinics of the Swedish University of Agricultural Sciences, were screened by enzyme-linked immunosorbent assay (ELISA) for antibodies to Toxoplasma gondii. 42% of cats, 23% of dogs and 1% of horses examined were found seropositive. Serum eller plasma från 244 tamkatter, 303 hundar och 219 sporthästar som provtagits vid djur-klinikerna vid Sveriges lantbruksuniversitet i Uppsala under 1986 och 1987 testades med ELISA för antikroppar mot Pre...
Ryder S, Bracho D.Antibodies against Venezuelan Equine Encephalitis Virus (VEEV) were studied in the human population of Mara District, Zulia State, Venezuela. Two hundred thirty nine blood samples were taken from the towns of San Rafael de Mara, Santa Cruz de Mara, La Sierrita-4 Bocas, Carrasquero, Isla de San Carlos e Isla de Toas, during june, july and september, 1988. Donors samples were classified by age, sex and serological titres. Eighty nine were less than 15 years old (37.2%) and 150, over 15 years old (62.7%). From the 239 samples, 224 were negative (93.7%) and 15 positive (6.3%). Our results indicate...
Derse D, Dorn P, DaSilva L, Martarano L.Equine infectious anemia virus (EIAV) encodes a tat gene which is closely related to the trans-activators encoded by the human and simian immunodeficiency viruses. Nucleotide sequence analysis of EIAV cDNA clones revealed that the tat message is composed of three exons; the first two encode tat and the third may encode rev.. Interestingly, EIAV tat translation is initiated at a non-AUG codon in the first exon of the message, perhaps allowing an additional level of gene regulation. The deduced amino acid sequence of EIAV tat, combined with functional analyses of tat cDNAs in transfected cells, ...
DiPietro JA, Lock TF, Todd KS, Davis JL.Eighteen pony foals inoculated with 1,500 +/- 109 infective Parascaris equorum eggs were given 0.02 ml of ivermectin vehicle (liquid)/kg of body weight, PO, (control); 0.2 mg of ivermectin paste/kg, PO; or 0.2 mg ivermectin liquid/kg, PO, on postinoculation day (PID) 28. Foals were euthanatized on PID 42, and the small intestinal contents were examined for P equorum larvae. The mean number of fourth-stage P equorum larvae in foals treated with ivermectin paste and liquid were 3.5 and 6, respectively. Significantly (P less than 0.01) higher mean numbers of larvae (1,250) were detected in foals ...
Wilson WD, Madigan JE.Diagnosis of bacterial septicemia was confirmed by results of bacteriologic culture of antemortem blood samples and/or necropsy specimens obtained from 47 foals up to 8 days old. Gram-negative bacteria were isolated from all 47 foals, and mixed infections with more than one organism were involved in 26 (55%). Escherichia coli, Actinobacillus spp, and Klebsiella pneumoniae were the most frequent isolates, infecting 55, 34, and 23% of foals, respectively. Gram-positive bacteria and anaerobic bacteria were isolated only from foals with mixed infections with gram-negative organisms. Clostridium pe...
Uppal PK, Yadav MP, Singh BK, Prasad S.A progenital disease encountered at one equine stud farm at Bangalore in Southern India during 1987 was investigated and confirmed as equine coital exanthema on the basis of characteristic lesions and clinical symptoms, isolation of equine herpes virus-3 (EHV-3) from the scabs collected from animals having active lesions and demonstration of neutralizing antibodies in the sera of recovered mares and stallion. This is the first authenticated report of the occurrence of equine coital exanthema in India due to EHV-3.
Biermann U, Herbst W, Krauss H, Schliesser T.During 1988 fecal and gut samples of 641 dogs, 198 cats, 576 calves, 108 piglets and 64 foals with diarrhoea were investigated for virus infections by electron microscopy. In samples of dogs and cats parvovirus was detected at a proportion of 21.9% and 16.7%, respectively; rotavirus alone or together with coronavirus was found only in 0.3-1.5% of the specimens. In samples of calves rotavirus, as well as coronavirus dominated with a detection rate amounting to 17.4% and 26.6% respectively (including 4.5% of mixed infections); parvovirus was present in a ratio of 0.5%. Specimens of piglets mainl...
Caple IW.Diarrhoea continues to be one of the more common and
important causes of economic loss in young animals (Anon
1978). Virus particles identified as rotaviruses, coronaviruses,
calci-like viruses, astroviruses, parvoviruses, and several others
have been detected by direct electron microscopy of ultracen-
trifuged samples of diarrhoeic faeces from young animals and
human infants over the past 20 years. Despite numerous stud-
ies on the many aetiological agents associated with neonatal
viral diarrhoea in recent years (Tzipori 1985), the challenge
for today’s new veterinary graduate is s...
Rice NR, Lequarre AS, Casey JW, Lahn S, Stephens RM, Edwards J.The amount and distribution of viral DNA were established in a horse acutely infected with the Wyoming strain of equine infectious anemia virus (EIAV). The highest concentration of viral DNA were found in the liver, lymph nodes, bone marrow, and spleen. The kidney, choroid plexus, and peripheral blood leukocytes also contained viral DNA, but at a lower level. It is estimated that at day 16 postinoculation, almost all of the viral DNA was located in the tissues, with the liver alone containing about 90 times more EIAV DNA than the peripheral blood leukocytes did. Assuming a monocyte-macrophage ...
Havelka B, Skarková A.During the period from 1985 to 1988 we determined 228 strains of streptococci isolated from samples of various sorts of biomaterials, mainly animals. From this set of streptococci we classified 207 strains into serological groups according to the Lancefield classification and about 30% strains into species by means of serological and biochemical methods. Most of the strains were allocated to group C (37.28%) and group Q (17.39%). 89 streptococci strains originated from pigs, 40 strains from horses, 13 from cattle, 12 from dogs, 9 from poultry and 8 from coypu. The other streptococci strains or...
Spurlock GH.The prognosis for returning horses with open joint injuries to athletic function is most closely related to the duration of the injury prior to treatment. Prompt diagnosis and appropriate therapy should yield a favorable result. Delayed diagnosis or inappropriate therapy that allow the wound to progress to an infected state makes the likelihood of return to athletic function poor. Refractory joint infection can occur despite early diagnosis and prompt appropriate therapy. The development of these infections is undoubtedly increased by tissue loss and gross contamination. Appropriate antibiotic...
Blancquaert AB, Colgan SP, Bruyninckx WJ.To identify the influence of technical factors on the in vitro motility of equine neutrophils towards streptococcus culture supernatant in an under-agarose assay, we studied the changes in eight cell migration parameters. The distances the phagocytes travelled by directed, random and spontaneous migration increased with incubation time, cell concentration and the gelatin and serum contents of the migration plates. The contribution of chemotaxis to the phagocyte migrations, however, decreased simultaneously. The directed and random, though not the spontaneous, migrations of the phagocytes incre...
O'Rourke KI, Perryman LE, McGuire TC.Antibody responses in horses with equine infectious anemia virus (EIAV) were examined to determine their cross-neutralizing capacity. Antibodies induced by infection with any of six biologically cloned variants of EIAV cross-neutralized multiple variants from the group. Anti-EIAV antibody was found in both the IgG and IgG(T) subclasses in plasmas with virus-neutralizing activity and the majority of antiviral antibody was of the IgG(T) subclass. Depletion of IgG(T) did not increase the neutralization indexes of either neutralizing or non-neutralizing plasma samples.
Magnarelli LA, Anderson JF.Class-specific and polyvalent ELISA were developed to detect IgM antibody or total immunoglobulins to Borrelia burgdorferi in equine sera. Analyses of 122 serum specimens, collected during 1985 from horses and ponies in tick-infested areas of Connecticut, revealed IgM antibody in 41 (34%) samples; titration end points ranged from 1:160 to 1:2,560. In polyvalent ELISA, 73 (16%) of 454 serum specimens contained IgM and/or IgG antibody. Seropositivity was highest (32%) for blood samples collected during May. Both ELISA procedures had comparable sensitivities.
Goetz TE, Holland CJ, Dawson JE, Ristic M, Skibbe K, Keegan KG, Johnson PJ, Schaeffer DJ, Baker GJ.The seroprevalence and seasonal trend of antibody titers against equine monocytic ehrlichiosis (Potomac horse fever) were determined in apparently healthy horses in selected areas of Illinois in 1986. Sera from 1,367 horses (6 months to 29 years old) were evaluated for the presence of antibodies against Ehrlichia risticii with indirect immunofluorescence. The majority (88%) of the horses were Thoroughbred or Standardbred racehorses. The number of horses with antibodies against E risticii was 229/1,367 (16.75%). The titers in these horses ranged from 1:10 to 1:640. As the year progressed, the n...
Gliatto JM, Alroy J.A horse with malignant lymphoma (histiolymphocytic) and cutaneous amyloidosis is described. The lymphoma involved the dura mater of the spinal cord and some of the peripheral lymph nodes. Multifocal amyloid deposits were present in the skin and subcutis of the ventral abdomen but not within the lymphoma cell infiltrates or in the viscera.
Alsing-Johansson T, Pedersen A, Bergström K, Sternberg-Lewerin S, Penell J, Bergh A.Equine dentistry has developed immensely and human dental equipment, such as handpieces, are often used. Measures to avoid the spread of infectious microorganisms are important, but this is challenging since handpieces are difficult to decontaminate. Thus, it is necessary to develop effective IPC measures in equine dentistry. The aim of this study was to contribute to the evidence needed for future evidence-based guidelines on IPC by investigating hygiene in equine dentistry. Used handpieces and dummies (i.e., handpieces not used during dental procedure, reflecting environmental bacterial cont...
Pégné JC, Duquesne F, Laugier C, Lequeux G, Petry S.The present study reports the isolation of A. hippocoleae from genital swabs of 15 apparently healthy mares (at least one had an abortion one month earlier) and describes the genotypic and phenotypic characterisation of these strains. The mares were of eight different breeds with a thoroughbred dominance and came from 11 breeding farms located in the French region of Brittany. 16S rRNA gene sequencing confirmed the species' identification by comparing it with reference strain A. hippocoleae CIP 106850. Some degree of natural divergence within A. hippocoleae was observed by 16S rRNA sequencing ...
Bertone AL, Jones RL, McIlwraith CW.The tarsocrural joints of 11 horses were inoculated with 1.2 to 2.16 x 10(6) viable Staphylococcus aureus organisms susceptible to a trimethoprim-sulfadiazine (TMP-SDZ) combination with minimal inhibitory concentration (MIC) of 0.25 micrograms of TMP/ml and 4.75 micrograms of SDZ/ml. Antimicrobial treatment consisted of oral administration of a TMP-SDZ combination--30 mg/kg of body weight given once daily (group-1 horses) or 60 mg/kg given as 30 mg/kg every 12 hours (group-2 horses). Paired serum and synovial fluid samples were obtained before intra-articular inoculation with the S aureus, aft...
Kim YK, Noh KB, Han CS, Moon JY, Yoon DK, Song KJ, Kim DJ, Kubera M, Maes M, Song JW.Borna disease virus (BDV) predominantly infects horses and sheep, causing a broad range of behavioural disorders. It is controversial whether BDV infects humans and causes psychiatric disorders. Objective: We searched for BDV-derived nucleic acids in blood of race horses and jockeys riding the horses. Methods: We assayed for the BDV genome in RNA extracted from peripheral blood mononuclear cells (PBMC) of 39 race horses and 48 jockeys. Two polymerase chain reaction protocols [one-tube reverse transcription-polymerase chain reaction (RT-PCR) and two-step RT-PCR] were used to assay BDV p24 and p...
Howard RD, McIlwraith CW, Trotter GW, Nyborg JK.To clone equine interleukin 1 alpha (IL-1 alpha) and equine interleukin 1 beta (IL-1 beta) and determine their full-length cDNA sequences. Methods: The mRNA isolated from lipopolysaccharide-stimulated cultured equine monocytes was reverse transcribed, and a cDNA library was constructed in a lambda phage. The cDNA library was screened by means of plaque hybridization with radiolabeled human IL-1 alpha and IL-1 beta cDNA probes. The cDNA nucleotide sequences for equine IL-1 alpha and equine IL-1 beta were determined by use of the dideoxy chain termination technique. The cDNA sequences were analy...
Matthews JB, Dowdall SM, Baudena MA, Klei TR, Kaplan RM, von Samson-Himmelstjerna G, Drögemüller M, Schnieder T.This collection of articles provides an in depth account of five presentations delivered during the Symposium on Equine Cyathostomins held at the 19th International Conference of the World Association for the Advancement of Veterinary Parasitology (WAAVP), New Orleans, Louisiana,10–14 August 2003. The symposium was organized and chaired by Ray M. Kaplan and Jacqui B. Matthews and focused on new developments in two major areas of current importance: the immunobiology of cyathostomin–horse interactions and anthelmintic resistance.
Schröder J, Swan GE.Ivermectin, described as 22,23-dihydroavermectin B1, was the compound chosen from the avermectin group of compounds for development as an antiparasitic agent in horses. A review of the literature indicates that parenteral administration in horses at 200 microgram/kg body mass is highly effective against the strongyles Strongylus vulgaris, Strongylus edentatus and triodontophorus spp., and adult and immature cyathostomes, including strains resistant to benzimidazole anthelmintics. Other nematodes controlled in horses include Oxyuris equi, Parascaris equorum, Trichostrongylus axei, and Habronema...
Lucchesi PM, Parma AE, Arroyo GH.Horses infected with Leptospira present several clinical disorders, one of them being recurrent uveitis. A common endpoint of equine recurrent uveitis is blindness. Serovar pomona has often been incriminated, although others have also been reported. An antigenic relationship between this bacterium and equine cornea has been described in previous studies. A leptospiral DNA fragment that encodes cross-reacting epitopes was previously cloned and expressed in Escherichia coli. Results: A region of that DNA fragment was subcloned and sequenced. Samples of leptospiral DNA from several sources were a...
Corstvet RE, Gaunt SD, Karns PA, McBride JW, Battistini RA, Mauterer LA, Austin FW.An enzyme-linked immunosorbent assay (ELISA) was used to detect antigen in plasma and antibody in serum of 3 horses inoculated with Ehrlichia equi. Clinical signs, including rectal temperature, were correlated with the antigen and antibody detection. ELISA was very efficient in detection of serum antibody. Antigen detection using monoclonal antibodies to E. equi and ELISA should be considered as a diagnostic method.
Hirsh DC, Smith BP.Horses in a riding stable sporadically excreted Salmonella agona, S anatum, and S newington in the feces. The three serotypes were isolated from apparently normal horses. The horses were sampled (the number sampled varied between 10 and 21) six times throughout a 13-month period. The greatest percentage of the horses (12 of 19, or 63%) were found to be excreting salmonella in September. Among the 12 horses excreting salmonella during this month, 8 (67%) were found to be excreting S agona.
Edington N, Wright JA, Patel JR, Edwards GB, Griffiths L.Equine adenovirus 1 was recovered after four to six passages from two out of three cases of cauda equina neuritis (CEN) using kidney monolayers. Similar treatment of lumbo-sacral spinal cord from six normal horses did not yield adenovirus. All three cases of CEN had antibodies to the neuritogenic myelin protein P2 while immunofluorescence demonstrated that autologous IgG bound to the myelin of affected nerves. Adenovirus was not detected in neural tissue by immunofluorescence.
Epp T, Waldner C, Leighton FA, Berke O, Townsend HG.The primary objectives of this study were to determine the seroprevalence of West Nile virus (WNV) infection of horses in Saskatchewan in 2003 and to identify risk factors for the infection. Blood samples were collected in August and October from 212 horses in 20 herds in 5 geographic zones. After accounting for within-herd clustering, the proportion of horses that had been infected with WNV, as determined by IgG and IgM antibody response, was 55.7% (95% confidence interval, 44.9% to 65.8%). The proportion of antibody-positive horses differed among herds (0% to 100%) and across ecoregions (20%...