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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.
Seroepidemiological survey of chlamydial infections in light horses in Japan. To investigate the overall prevalence of chlamydial infections in light (i.e. non-draught) horses in Japan, 599 sera obtained from 12 localities in 1991 were tested for complement fixation antibodies. The mean antibody positive rates of the all sera were 15.2% (91/599) and the regional positive rates were higher in Honshu (19.1%, 48/251) and Kyushu (20.0%, 20/100) than in Hokkaido (9.3%, 23/248). In Honshu, the highest rate (56.0%, 28/50) was observed in Utsunomiya. Analysis of the positive rate in different age groups showed that the 2-5 years age-group had the highest prevalence of chlamydia...
Effect of influenza A/equine/H3N8 virus isolate variation on the measurement of equine antibody responses. This study has tested the effect of using homologous or heterologous equine influenza A virus isolates to evaluate serum antibody levels to influenza A virus in vaccinated and naturally-infected horses. In addition, the potential effect of antigenic selection of virus variants in egg versus tissue culture propagation systems was studied. Serum antibody levels in samples from horses recently infected with a local influenza A virus isolate (A/equine 2/Saskatoon/1/90) or recently vaccinated with a prototype isolate (A/equine 2/Miami/1/63) were assessed by hemagglutination inhibition and by single...
The identification of equid herpesvirus 1 in paraffin-embedded tissues from aborted fetuses by polymerase chain reaction and immunohistochemistry. Paraffin-embedded organ samples from 28 aborted fetuses and three foals, partly archival and partly sampled in 1991, were examined by polymerase chain reaction (PCR) and immunohistochemistry for the presence of DNA and antigens, respectively, specific for equine herpesvirus 1 (EHV-1). Virologic examination had been performed on 23 of the aborted fetuses. DNA fragments specific for EHV-1 were identified by PCR, and EHV-1 antigens were identified in situ by immunohistochemistry, with an agreement between the methods of 94% (kappa = 0.85). Compared with virus isolation, PCR agreement was 87% (kap...
Clostridium septicum septicemia in a neonatal foal with hemorrhagic enteritis. Clostridium septicum was isolated by anaerobic culture of blood collected from a 3-day-old foal with hemorrhagic enteritis and signs suggestive of septicemia. The foal responded well to treatment with intravenous fluids, antibiotics, plasma, and oral gastrointestinal protectants. One month after apparent complete recovery from the septicemia and hemorrhagic enteritis, the foal was euthanized during an acute episode of colic that was caused by severe, strangulating intestinal adhesions, thought to have formed as a result of peritonitis secondary to the hemorrhagic enteritis. The value of anaero...
Serological titers of equine monocytic ehrlichiosis associated with gastro-intestinal disorders and serological follow-up on two endemic farms. The purpose of this work was to study the association of positive serological titers to Ehrlichia risticii, the causative agent of equine monocytic ehrlichiosis (EME) with gastro-intestinal disorders in hospitalized horses referred to The Ohio State University College of Veterinary Medicine Teaching Hospital (OSU VMTH). In addition, serological titers for E. risticii were monitored in two horse populations with endemic EME for one season to monitor temporal changes in titers. A statistically significant difference was found between the proportion of the total hospitalized horse population pres...
Physical and functional characterization of transcriptional control elements in the equine infectious anemia virus promoter. Equine infectious anemia virus (EIAV) is a lentivirus that causes a chronic disease of horses characterized by cyclic episodes of fever, anemia, and viremia. Although the genome and promoter of EIAV are much less complex than those of its relatives the primate immunodeficiency viruses, the cellular proteins that activate and regulate transcription of EIAV have not yet been identified. In this report, we show by electrophoretic mobility shift assays and DNase I footprinting that the EIAV promoter contains multiple binding sites for ubiquitous, cell type-specific, and inducible cellular proteins...
Intermittent antimicrobial infusion for management of a septic distal interphalangeal joint in a horse. A 13-month-old Quarter Horse colt sustained a puncture wound to the frog region of the foot, which penetrated the navicular bursa and distal interphalangeal joint, 7 days prior to examination. A street-nail procedure was performed to debride the tract and provide drainage of the navicular bursa and distal interphalangeal joint. An indwelling lavage system was placed through the dorsal aspect of the joint and antimicrobials were infused intermittently to supply a high local concentration of drug and to frequently lavage the distal interphalangeal joint and navicular bursa.
Culture confirmation of the carrier status of Babesia caballi-infected horses. Culture of horse blood for Babesia caballi identified four carrier horses among nine previously infected horses. Three of the carriers had no detectable parasitemias on stained blood smears, and sera from two carrier horses were complement fixation test negative. Three cultures were continuously cultivated. Cryopreserved fourth-passage B. caballi was successfully reestablished in vitro. Blood from a 10th horse previously subinoculated with blood from a suspected carrier was cultured, with negative results.
Cutaneous pythiosis in horses from Brazil. Equine pythiosis was studied in five animals from two farms located in a swampy region of southern Brazil (Rio Grande do Sul State). Granulomatous lesions exuding necrotic material and containing a central yellow and firm tissue core, the 'kunker', were observed on the top of the nose of one horse, on the abdomen of two horses and on the hind limbs of two other animals. Direct microscopic preparations, histopathological examination of lesion material, and macroscopic and microscopic characteristics of the isolates confirmed the diagnosis of pythiosis. Surgical intervention of the inflammatory ...
Serological diagnosis of Trypanosoma evansi (Steel, 1885) in horses using a direct agglutination test. A direct agglutination test is described to diagnose 'Mal de Caderas' caused by Trypanosoma evansi. The antigen used was a suspension of trypsin-treated parasites stabilized with formalin. The test was evaluated in horses with both natural and experimental infections. Test sensitivity and specificity were 94 and 97%, respectively. Treatment of serum with 2-mercaptoethanol before testing permitted the differentiation of IgM and IgG antibodies, and possible differentiation of current infection from past exposure to the parasite. The antigen was stable over a 6-month evaluation period and also sh...
Characterisation of equine influenza isolates from the 1987 epizootic in India by nucleotide sequencing of the HA1 gene. Two A/Equi-2 (H3N8) isolates were obtained during the 1987 Indian equine influenza epizootic. The sequence of the Ludhiana/87 HA1 gene revealed that this isolate was very similar to recent European and North American isolates of equine influenza. In contrast, the Bhiwani/87 HA1 gene was nearly identical to the Miami/63 prototype H3 sequence. These results support the antigenic analysis previously carried out on these isolates using monoclonal antibodies. However, the finding that Bhiwani/87 is so similar to Miami/63, coupled with the finding that equine H3N8 influenza viruses have previously b...
Replication of equid herpesvirus-1 in the vaginal tunics of colts following local inoculation. Equid herpesvirus-1 (EHV-1; Ab4 isolate) was inoculated unilaterally into the cavum vaginale of four pony colts under general anaesthesia. The animals were monitored daily for evidence of scrotal or testicular swelling and euthanased electively on days 3, 4, 6 and 12 after infection. Detailed pathological examination of the male genital tract was carried out. In animals examined at days 3 and 4 after infection, replication of EHV-1 was detected bilaterally in mesothelial and endothelial cells of the parietal and visceral vaginal tunics. The mesothelial infection had resolved by day 12 after in...
Report of the Thirteenth Meeting of the OIE Ad hoc Group on Non Tsetse-Transmitted Animal Trypanosomoses. There is increasing interest in many parts of the world in trypanosomoses other than those transmitted by tsetse flies, as shown by numerous research projects and field studies. The refinement of techniques for studying the behaviour of trypanosomes (techniques of molecular biology) in axenic culture or in the parasitised host has led to progress in diagnosis and immunology, and a rational approach to chemotherapy and chemoprophylaxis of these infections. Field trials of enzyme-linked immunosorbent assays in Africa, Asia and South America have shown that these tests may now be regarded as reli...
Structural features of the trans-activation response RNA element of equine infectious anemia virus. A 25-nucleotide RNA with the sequence of the trans-activation response (TAR) element of equine infectious anemia virus (EIAV) was analyzed by biochemical methods and by one- and two-dimensional NMR spectroscopy. NMR, nuclease probing, and polyacrylamide gel migration rates show that the RNA consists of an A-helical stem capped by two non-Watson-Crick U-G base pairs and a compact four-nucleotide loop. The loop is stabilized by base stacking, with loop nucleotides C12 and C15 stacked upon U11 and G16, respectively. Near the 5' end of the molecule, the stem contains a bulge at nucleotide C2, most...
Detection of antibodies against equine herpesvirus types 1 and 4 by using recombinant protein derived from an immunodominant region of glycoprotein B. The N-terminal fragment comprising residues +1 to +50 (gB1-50) of equine herpesvirus type 1 (EHV-1) glycoprotein B was expressed as a glutathione S-transferase fusion protein in Escherichia coli. Recombinant gB1-50 (rgB1-50) was recognized in immunoblots by sera from rabbits immunized with EHV-1 and by convalescent-phase sera from horses with natural EHV-1 infections. An enzyme-linked immunosorbent assay (ELISA) for monitoring antibody levels against EHV-1 was developed by using rgB1-50, and its specificity was assessed with a panel of reference antisera against other equine viruses. A specifi...
Trypanosomiasis of domestic animals in China. Trypanosomiasis caused by Trypanosoma evansi (surra) is a problem of great economic importance in livestock in China because it affects important working animals: buffaloes in the south and east, and horses and cattle in the north and west. In addition, buffaloes are an important source of meat and leather for the Chinese population. In the north and west, T. evansi is found mainly in camels, whereas in the east, the south and the southwest, it is primarily buffaloes, cattle and horses that are affected by this parasitic flagellate. Although trypanosomiasis is one of the most important parasit...
The genome of equine herpesvirus type 2 harbors an interleukin 10 (IL10)-like gene. A gene was identified within the DNA sequences of the EcoRI DNA fragment N (4.3 kbp) of the genome of equine herpesvirus type 2 (EHV-2) coding for a protein (179 amino acid residues) homologous to the cytokine synthesis inhibitory factor (CSIF; interleukin 10) of the human and mouse, and to the Epstein-Barr virus (EBV) protein BCRF1. This finding is further significant evidence that the interleukin 10 (IL-10) and/or IL-10-like gene can indeed be present in the genomes of members of the herpesviral family.
Inhibitory effects of horse serum on immunoassay of horse ferritin. The effects of horse serum on the immunoassay of horse ferritin were investigated using two sandwich enzyme-linked immunosorbent assay (ELISA) systems. In System A, affinity-purified antibody to horse spleen ferritin and its conjugate with alkaline phosphatase were used as the first and second antibodies, respectively. In System B, whole antiserum and its conjugate with the enzyme were used. The recoveries of horse spleen ferritin added to horse sera were very low in either system (50-71% in System A; 42-79% in System B). However, heat treatment of the sera at 75 degrees C for 15 min improved ...
Protein characterization of Babesia equi piroplasms isolated from infected horse erythrocytes. Proteins of Babesia equi piroplasms were characterized. The piroplasms of B. equi were purified by lysis of infected horse erythrocytes with N2 gas cavitation followed by separation in Percoll density-gradient centrifugation. The relative molecular weights (Mr) of major proteins separated by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis were 18, 28, 30, 41, 43, 54, 66.5, and 96 kDa. Immunoblot analysis using serum from an experimentally infected horse revealed six immunodominant proteins of 15, 18, 28, 30, 41, and 96 kDa. Two immunodominant proteins of 18 and 28 kDa...
A review of techniques for the serologic diagnosis of equine infectious anemia. No abstract available
Current status of the diagnosis and control of African horse sickness. African horse sickness (AHS) is an infectious, non-contagious, highly fatal viral disease of Equidae, transmitted by arthropod vectors of the genus Culicoides, and endemic in Africa south and east of the Sahara. The disease is caused by a virus of the Reoviridae family, genus Orbivirus, and 9 serotypes have been recognized. Recent outbreaks of AHS in the Iberian peninsula and Northern Africa emphasize the need for accurate diagnosis and rapid implementation of control measures. In this paper, the epizootiological factors, clinical signs and necropsy findings of AHS are discussed, and an update...
Epizootic of equine influenza in 1969 in Poland. Epidemiological observations on the course and spread of equine influenza in Poland during the 1969 epizootic were carried out. The dynamics of the spread of the disease in the country are shown graphically by voivodship. The disease incidence and mortality rates for the entire country are also shown. The highest incidence of disease and mortality rates were found to be in November 1969. A/equi-2/Warsaw/69 was identified as the causal virus. It caused the largest epizootic in the country since 1954.
Poliomyelomalacia and ganglioneuritis in a horse with paralytic rabies. No abstract available
Laboratory transmission of eastern equine encephalomyelitis virus to chickens by chicken mites (Acari: Dermanyssidae). Pools of adult female chicken mites, Dermanyssus gallinae (De Geer), were allowed to feed on chicks that had been inoculated with eastern equine encephalomyelitis (EEE) virus and that had a viremia level of 10(6.2)-10(6.6) plaque-forming units per milliliter of blood. Virus remained detectable by plaque assay in samples of these mites for 30 d after the infectious blood meal. Virus was not recovered from any of 151 progeny of virus-exposed female mites. Mites that had fed on viremic chicks were allowed to feed on naive chicks 3, 7, 11, 15, or 30 d later. EEE virus was transmitted to chicks by ...
