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equine gamma herpesviruses EHV-2 and EHV-5 have been detected in the gastric mucosa of horses. 42 We hypothesized that equine gamma herpesvirus infections are associated with EGGD. Little has been done to compare endoscopy or postmortem findings with

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in American Journal of Veterinary Research
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Outbreaks of neurologic disease caused by mutant hypervirulent strains (neuropathotypes) of EHV-1 have been reported with increasing frequency during the past several years. 1–6 Equine herpesvirus-1 myeloencephalopathy has an impact on equine

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in American Journal of Veterinary Research

Equine herpesvirus type 1 is an important pathogen of horses that causes major losses to the equine industry worldwide. In addition to respiratory disorders, EHV-1 can cause abortion, neonatal foal death, and EHM. An SNP in the catalytic subunit

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in American Journal of Veterinary Research
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Epizootics of neurologic disease caused by EHV-1 have been reported with increasing frequency in the United States during the past several years. 1 Characterized by high neurologic morbidity and case fatality rates, resistance to prevention by

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in American Journal of Veterinary Research

EHV-1 vaccines, abortion secondary to EHV-1 infection is still a concern for mares residing on commercial stud farms. 1 The virus can cause lifelong latent infection, with periodic reactivation and shedding important in maintaining EHV-1 in the horse

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in Journal of the American Veterinary Medical Association

industry and have a financial and emotional toll on owners of affected horses. 1 When horses are infected with EHV-1, thrombi develop within various blood vessels, including those that supply the spinal cord and placenta. 2–4 These thrombi are believed to

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in American Journal of Veterinary Research

Infection with EHV-1 is associated with different signs of disease in different classes of horses; young horses are likely to develop upper respiratory tract signs, pregnant mares may abort their fetuses, and mature horses are most susceptible to

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in American Journal of Veterinary Research

Abstract

Objective—To compare methods of detecting equine herpesvirus type 1 (EHV1)- and EHV4-specific antibodies in horse sera.

Sample Population—33 acute and convalescent serum samples from experimentally or naturally infected horses after confirmed EHV1 or EHV4 infection.

Procedure—For each sample, serum antibody titers against EHV1 and EHV4 were determined by use of virus neutralization (VN) and complement fixation (CF) assays. The ELISA absorbance values for each serum sample were determined against the EHV1 and EHV4 recombinant ELISA antigens. Values obtained for acute and convalescent sera in each assay were compared.

Results—Following experimental infection of foals, EHV1 or EHV4 antibodies that were specific for the inoculating virus were detected only by use of the ELISA. Results of VN and CF assays indicated that the foals seroconverted to EHV1 and EHV4 following infection with EHV4 only. After EHV1-induced abortion, myeloencephalitis, or respiratory tract disease, the VN and CF assay results revealed seroconversion to EHV1 and EHV4, whereas results of the ELISA revealed seroconversion to EHV1 only. Similarly, after confirmed EHV4-induced respiratory tract disease, increases in EHV4-specific antibodies were detected only by use of the ELISA with no indication of an increase in EHV1 antibodies. The CF and, to a lesser degree, VN assays revealed that seroconversion to EHV1 and EHV4 occurred between the time of obtaining acute and convalescent serum samples.

Conclusions and Clinical Relevance—The EHV1/ EHV4 type-specific antibody ELISA clearly identifies horses that have been infected with EHV1 or EHV4 by use of acute and convalescent sera. Results of VN and CF assays indicate that cross-reactive antibodies greatly limit their use. (Am J Vet Res 2005;66:921–928)

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in American Journal of Veterinary Research

Summary

The ability of monovalent and bivalent equine herpesvirus (EHV) vaccines to stimulate cellular and antibody responses to EHV-1 and EHV-4 was compared in healthy horses. Comparison of data from lymphocyte blastogenesis tests in which live viruses were used as antigens and that were conducted prior to vaccination and after 2 vaccinations revealed that horses given modified-live EHV-1 had significant increases in proliferative responses to EHV-1 (P = 0.03) and EHV- 4 (P = 0.04). Responses to EHV-1 and EHV-4 in horses given the inactivated-virus bivalent vaccine were less; however, significant differences were not noticed when postvaccinal lymphocyte blastogenesis tests were compared between the groups of vaccinees.

Interleukin-2 activity was not detected in leukocyte cultures from either group of vaccinees following stimulation with live EHV-1 or EHV-4; however, interferon activity was found in similar cultures from both groups of vaccinees. For EHV-4, interferon activity in cultures from both groups of vaccinees was significantly (P < 0.05) greater than that in leukocyte cultures from unvaccinated controls.

Both vaccines induced significant (P < 0.05) increases in serum antibodies that neutralized EHV-1 infectivity. The ELISA for EHV-1 and EHV-4 antibodies revealed that both vaccines induced significant (P < 0.05) increases (compared with preinoculation values) in antibodies reactive with these 2 types of EHV. Total serum antibody responses, as measured by ELISA, to EHV-1 and EHV-4 were significantly (P < 0.05) higher in horses that received the bivalent inactivated-virus vaccine, compared with that in horses that received monovalent vaccine. Evaluation of these data revealed that vaccination with modified-live EHV-1 can stimulate cellular and antibody responses that cross-react with EHV-4.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate use of the acupuncture meridian test for detection of recent or recently reactivated equine herpesvirus type 1 (EHV-1) infection in horses with decreased performance.

Design—Case-control study.

Animals—40 horses.

Procedure—Physical and neurologic examinations were performed, and acupuncture points on the bladder meridian were tested for sensitivity reactions in case and control horses. Polymerase chain reaction assays were performed to determine whether EHV-1 or equine herpesvirus type 4 (EHV-4) DNA could be detected in peripheral blood mononuclear cells. Complement fixation (CF) tests for detection of antibodies against EHV-1 and EHV-4 and virus neutralization (VN) tests for detection of antibodies against EHV-1 were performed on paired serum samples obtained 3 weeks apart.

Results—There was a significant difference in skin sensitivity in the cervical, sacral, and gluteal regions and flank between case and control horses. By use of the meridian test, all case horses were sensitive to manipulation of all acupuncture points believed to be associated with EHV infections, whereas only a few control horses were sensitive at an occasional point. Equine herpesvirus type 1 or EHV-4 viremia was not detected in any horses. Mean ± SD VN antibody titers against EHV-1 were not significantly different between the 2 groups. Mean ± SD CF antibody titers against EHV-1 obtained 3 weeks after the initial samples were higher in case horses than control horses; however, unequivocal seroconversion was not detected.

Conclusions and Clinical Relevance—Results of the meridian test in case horses were associated with sensitivity reactions similar to those detected by physical and neurologic examinations; however, an unequivocal association with EHV-1 or EHV-4 infection was not detected. ( J Am Vet Med Assoc 2004;225:554–559)

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in Journal of the American Veterinary Medical Association