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Topic:Infectious Disease
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.
Isolation and characterization of monoclonal antibodies against an attenuated vaccine strain of equine herpesvirus type 1 (EHV-1). The production and differentiation of monoclonal antibodies (mabs) against the Rac-H strain of EHV-1 used as an attenuated live vaccine to prevent rhinopneumonitis and abortion is described. Seven different antigenic sites were detected by the 15 mabs produced. EHV-1 specific mabs as well as EHV-1 and -4 common mabs could be established, allowing easy typing of EHV isolates. One mab recognized the vaccine strain only. This reaction was used to investigate a possible involvement of the vaccine strain in cases of abortion. Common antigenic determinants with EHV-1,-3,-4 and BHV-1 could also be de...
Efficacy of ivermectin in paste and injectable formulations against microfilariae of Onchocerca cervicalis and resolution of associated dermatitis in horses. The efficacy of a single dose of ivermectin (0.2 mg/kg), in injectable or paste formulations, against microfilariae of Onchocerca cervicalis and associated skin lesions was evaluated in 20 naturally infected horses during midsummer months in Louisiana. All horses had clinical signs of dermatitis of the ventral midline and/or limbs, shoulders, thorax, and withers. Efficacy was monitored at 21, 42, and 63 days after treatment. Procedures done at these intervals included microfilarial counts of 6-mm skin biopsy specimens of affected ventral midline, grading of gross lesions, and photography and h...
cis- and trans-acting regulation of gene expression of equine infectious anemia virus. Deletion analysis of the equine infectious anemia virus long terminal repeat revealed that sequences responsive to virus-specific transactivation are located within the region spanning the transcriptional start site (-31 to +22). In addition, an active exon of a trans-acting factor (tat) was identified downstream of pol and overlapping env (nucleotides 5264 to 5461). Activation by tat is accompanied by an increase in the steady-state levels of mRNA directed by the equine infectious anemia virus long terminal repeat.
Characterization of Berne virus genomic and messenger RNAs. From 380S particles of Berne virus (proposed family Toroviridae) one species of polyadenylated RNA was isolated. Using agarose gel electrophoresis its length was estimated as 20 kb or greater. When assayed under hypertonic transfection conditions genomic RNA was found to be infectious; RNase treatment destroyed the infectivity. The positive polarity of the molecule was confirmed by filter spot hybridization using cDNA prepared against poly(A)-selected RNA from infected cells. In embryonic mule skin cells infected with Berne virus the presence of five virus-specific, polyadenylated RNA species ...
Adherence of streptococcal isolates from cattle and horses to their respective host epithelial cells. Adherence of Streptococcus dysgalactiae isolates from cattle and S equi isolates from horses to their respective host epithelial cells was compared with the adherence of S pyogenes to human epithelial cells. The adherence was quantitatively determined by use of fluorescein-labeled streptococci. All 3 streptococcal species adhered selectively to their respective host cells. The mechanism of adherence was evaluated by binding studies with adhesive plasma protein, fibronectin. Although all 3 streptococcal species bound fibronectin, S dysgalactiae and S equi interacted preferentially with a 210-ki...
Pathogenicity for horses of original Sagiyama virus, a member of the Getah virus group. Sagiyama virus is a member of the Getah virus group. Its pathogenicity for horses was examined. All the horses infected with the original 4 strains of Sagiyama virus (M6/Mag 33, Mag 121, Mag 132 and Mag 258) developed pyrexia ranging from 39.0 to 40.0 degrees C. Other clinical signs, characterized by eruptions, edema in the hind legs, enlargement of the submandibular lymph node and mild leukopenia, were also manifested. Viremia occurred 1-4 days post-inoculation (p.i.). Virus was recovered from spleen, liver, lung and various lymph nodes of a horse autopsied on Day 4 p.i. The maximum titer of ...
Characterization of an equine herpesvirus type 1 gene encoding a glycoprotein (gp13) with homology to herpes simplex virus glycoprotein C. The molecular structure of the equine herpesvirus type 1 (EHV-1) gene encoding glycoprotein 13 (gp13) was analyzed. The gene is contained within a 1.8-kilobase AccI-EcoRI restriction fragment mapping at map coordinates 0.136 to 0.148 in the UL region of the EHV-1 genome and is transcribed from right to left. Determination of the nucleotide sequence of the DNA fragment revealed a complete transcriptional unit composed of typical regulatory promoter elements upstream to a long open reading frame (1,404 base pairs) that encoded a 468-amino-acid primary translation product of 51 kilodaltons. The p...
Immune responses are required to terminate viremia in equine infectious anemia lentivirus infection. Six normal and four immunodeficient horses were injected with a cloned variant of equine infectious anemia virus (EIAV). The six normal horses had detectable EIAV in their plasma by 7 days postinjection. During their primary viremic episode, which was accompanied by fever and anemia, maximum titers of EIAV in plasma ranged from 10(3.8) to 10(4.8) 50% tissue culture infective doses per ml. All six normal horses cleared detectable virus from their plasma by 21 to 35 days after injection. Horses with combined immunodeficiency became viremic by 9 days postinjection and also developed anemia. In co...
[Various aspects of horse sickness]. The aetiology, symptoms, diagnosis and control of African horse sickness are described. Special attention is paid to the introduction and epizootiology of the disease in Spain and its consequences in respect to the international trade of horses.
Corynebacterium folliculitis in a horse. A 7-year-old Thoroughbred was examined for evaluation of mildly pruritic multiple skin lesions that had progressed from nodules to alopecia and crusts. Folliculitis caused by Corynebacterium pseudotuberculosis was diagnosed by bacterial culture. Oral treatment with a trimethoprimsulfadiazine paste resulted in resolution of all lesions, with normal hair regrowth.
Validation of a radioimmunoassay for measurement of gastrin in equine serum. A commercial radioimmunoassay kit designed for measuring gastrin in human serum was validated for use with equine serum. This nonextraction, double-antibody procedure uses an antiserum with broad specificity for molecular forms of gastrin. Synthetic human gastrin (G17-I) was added to pooled equine serum, and the observed assay values were compared with the mass added. Recovery was 99 to 115% in the gastrin concentration range of 40 to 640 pg/ml. Dilutions of postprandial serum with serum from fasted horses were assayed, and the inhibition curves were compared with those of the human gastrin ki...
Hemorrhagic necrotizing enterocolitis associated with Clostridium difficile infection in four foals. Severe hemorrhagic necrotizing enterocolitis was determined to be the cause of death for 4 foals. Toxigenic Clostridium difficile was isolated form the intestine of each foal, and large, gram-positive, rod-shaped bacteria lined the surface of necrotic villi. This finding of toxigenic C difficile associated with enteritis in foals adds another possible cause to the list of infectious agents that should be considered when evaluating foals with enteritis. Definitive diagnosis requires a thorough diagnostic evaluation, including procedures that will identify the organism and demonstrate its toxige...
Some aspects of the epidemiology of equine salmonellosis. A survey of 2 horse populations was done to detect the number of asymptomatic faecal excretors of Salmonella sp. 1201 faecal samples from 250 horses hospitalised at the University of Sydney were cultured. Three serotypes, S. typhimurium (4 horses), S. anatum (2) and S. tennessee (1) were isolated from 7 horses (2.8%). None was detected in 75 mares similarly examined at a thoroughbred stud farm. In retrospect, S. typhimurium was also the most common (70%) of the 19 serotypes recovered from 171 horses with clinical salmonellosis seen at Camden, 1969 to 1986. Forty cases occurring since 1983 were...
Expression of lectin binding in cutaneous papillomas of animals. A group of spontaneously occurring animal papillomas which were negative or positive for papillomavirus group-specific antigen were examined with a battery of biotinylated lectins including Con A, WGA, succinylated-WGA, PNA and UEA-I. Canine papillomas, equine papillomas, white-tailed deer fibromas, mule deer fibromas, and bovine fibropapillomas were examined. Each lectin had a specific staining pattern. No obvious differences in staining patterns between normal skin, viral antigen-positive and -negative neoplasms were identified. This may be due to the well-differentiated and organized nature...
Characterization of the serological cross-reactivity between glycoproteins of the human immunodeficiency virus and equine infectious anaemia virus. The reported serological relatedness between the major glycoproteins of human immunodeficiency virus (HIV gp120) and equine infectious anaemia virus (EIAV gp90) was examined using purified antigens in radioimmunoprecipitation (RIP), radioimmunoassay (RIA) and immunoblot assays with reference serum from acquired immunodeficiency syndrome (AIDS) patients, an anti-gp120 goat serum and EIAV-infected horse serum. To assess the contributions of glycoprotein oligosaccharide and peptide components to any observed reactivities, antigens treated with endoglycosidase F to remove carbohydrate were assayed...
Characterization of the genome of equine herpesvirus 1 subtype 2. The genome structure of equine herpesvirus 1 (EHV-1) subtype 2 was shown by electron microscopic studies and restriction endonuclease site mapping to comprise two covalently linked segments (L, 109 kbp; S, 35 kbp). The S segment contains a unique sequence (US) flanked by a substantial inverted repeat (TRS/IRS). Thus, the genome structure of EHV-1 subtype 2 is similar to that published previously for EHV-1 subtype 1, but the two subtypes differ in the occurrences of EcoRI and BamHI restriction sites. Hybridization studies using cloned EHV-1 DNA showed that the genome of EHV-1 subtype 2 is colin...
Occurrence of Clostridium tetani in soil and horses. The annual incidence of tetanus in the RSA is up to 300 cases with more than 50% of these coming from Natal/KwaZulu. The condition of playing fields and the excretion of Clostridium tetani by horses was therefore investigated. The overall contamination rate of soils in the Durban area is lower than that of published data from other parts of the world, for instance 28% for Durban in comparison with 31-42% for Japan and Quebec. A rugby field in the Transvaal showed 40% contamination and a pasture used for horses for more than 20 years 65%. No case of human or equine tetanus has ever been reporte...
An investigation into alternative methods for the serodiagnosis of dourine. The complement fixation test (CFT), indirect fluorescent antibody test (IFAT), card agglutination test for trypanosomiasis (CATT) and enzyme-linked immunosorbent assay (ELISA) were compared in their application to the serological diagnosis of Trypanosoma equiperdum infection in 43 horses. The CFT remains a reliable test for dourine, especially in countries where other members of the subgenus Trypanozoon do not occur. The IFAT is a good 'back-up' test, but, requiring skilled operators it has the disadvantage of making it labour intensive, and interpretation of results subjective. This makes it ...
Protection against experimental infection with influenza virus A/equine/Miami/63 (H3N8) provided by inactivated whole virus vaccines containing homologous virus. Thirty-one ponies immunized with inactivated virus vaccine containing A/equine/Miami/63 (H3N8) virus and six seronegative ponies were experimentally challenged with the homologous virus strain. All 6 unvaccinated ponies and 11 out of 31 vaccinated ponies became infected. A clear relationship between pre-challenge antibody, measured by single radial haemolysis (SRH), and protection was demonstrated as judged by virus excretion, febrile responses and antibody responses. Those ponies with SRH antibody levels greater than 74 mm2 were completely protected against challenge infection by the intranas...
Epidemiologic survey of diarrhea in foals. Epidemiologic and etiologic data about diarrhea in foals were collected under a planned prospective recording and monitoring study. The survey and monitoring procedures included a survey to obtain an overview of current horse management practices on participating farms, a daily health record survey to obtain information on mares and their foals, and collection of feces from 19 of 144 diarrheic foals and 10 age-matched nondiarrheic foals for electron microscopy, ELISA for rotavirus, and bacteriologic culture. Coronavirus was detected in the feces of diarrheic as well as clinically normal foals....
