Article

Outbreak of neurologic disease caused by equine herpesvirus-1 at a university equestrian center.

University Equine Veterinary Services, Findlay, OH 45840, USA.
Journal of Veterinary Internal Medicine (Impact Factor: 2.22). 01/2007; 21(1):157-65. DOI: 10.1892/0891-6640(2007)21[157:OONDCB]2.0.CO;2
Source: PubMed

ABSTRACT Equine herpesvirus type 1 (EHV-1) infection causes neurologic disease in horses. However, risk factors for the disease and long-term prognosis are poorly characterized.
There are identifiable risk factors for equine herpes-1 myeloencephalopathy.
The entire population of 135 horses housed within the equestrian facility.
A descriptive study investigated the clinical, serologic, virologic, and management aspects of an outbreak of EHV-1 myeloencephalopathy.
Out of 135 horses at the facility, 117 displayed signs of EHV-1 infection. Forty-six horses developed neurologic deficits characterized by symmetrical hind limb ataxia and weakness. Twelve horses that developed neurologic deficits became recumbent and did not survive. The development of severe neurologic deficits during the outbreak was associated with the presence of residual deficits at the 6-month examination. Within 1 year of the outbreak onset, all horses that survived had returned to an exercise level comparable to that experienced before the outbreak. Factors associated with the development of neurologic disease included age of > 5 years, location in the south or arena stall areas, and highest rectal temperature on day 3 or later of the febrile period.
Being > 5 years of age, having had a rectal temperature of > 103.5 degrees F, and highest rectal temperature occurring on or after the 3rd day of the febrile period were the factors most predictive of the development of neurologic disease and death. Data obtained during this outbreak substantiate previous findings relating to clinical aspects and diagnosis of EHV-1 myeloencephalopathy. The prophylactic and therapeutic use of acyclovir during this outbreak is described.

Download full-text

Full-text

Available from: Stephen M Reed, Mar 09, 2014
1 Follower
 · 
91 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Although equine herpesvirus myeloencephalopathy (EHM) is a sporadic and relatively uncommon manifestation of equine herpesvirus-1 (EHV-1), it has the potential for causing devastating outbreaks in horses. Up till now, there were no reported EHM outbreaks in donkeys and mules. This study describes the isolation and molecular characterization of EHV-1 from clinically EHM-affected horses (n = 6), mules (n = 3) and donkeys (n = 82) in Ethiopia during outbreaks from May 2011 to December 2013. The incidence of EHM cases was higher from April to mid-June. EHM in donkeys was more severe and death without clinical signs of paralysis, and recumbency was frequently observed. The main age of affected equines ranged from 7 to 10 years (n = 51; 56.0%), and females (n = 58; 63.7%) were more affected than males. The incidence of neuropathogenic (D752 ) and non-neuropathogenic (N752 ) variants of EHV-1 from EHM-affected equines in Ethiopia was assessed by sequencing the DNA polymerase gene (ORF30) of the EHV-1 isolates. The results indicated that from the total of 91 clinically affected equines, 90 (98.9%) of them had an ORF30 D752 genotype. An ORF30 N752 variant was only found in one donkey. Analysis of ORF68 as grouping marker for geographical differences showed that the Ethiopian EHV-1 isolates belong to geographical group 4. Due to the fatal nature of EHV-1 in donkeys, it would be interesting to examine the pathogenesis of EHM in this species. At present, there is no vaccine available in Ethiopia, and therefore, outbreaks of EHV-1 should be controlled by proper management adaptations. In addition, it is important to test the efficacy of the commercial vaccines not only in horses, but also in donkeys and mules. © 2015 Blackwell Verlag GmbH.
    Transboundary and Emerging Diseases 05/2015; DOI:10.1111/tbed.12377 · 3.12 Impact Factor
  • The Veterinary clinics of North America. Equine practice 12/2011; 27(3):573-87. DOI:10.1016/j.cveq.2011.08.008 · 1.05 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The incidence of reported cases of equine herpesvirus myeloencephalopathy (EHM) caused by infection with neuropathogenic strains of equine herpesvirus 1 (EHV-1) has markedly increased over the last decade in many Western countries. The purpose of this study was to estimate the prevalence of the neuropathogenic (G2254) and non-neuropathogenic (A2254) variants of EHV-1 among isolates associated with abortions in Polish stud farms. The results of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing were consistent, and showed that two out of 64 abortions (3.1%) were induced by the neuropathogenic genotype G2254. All remaining 18 EHV-1 positive abortion cases (28.1%) were caused by the non-neuropathogenic genotype A2254. Most of the abortions in mares in Poland from 1999 to 2012 were associated with non-neuropathogenic strains of EHV-1. However, the presented data indicate that the neuropathogenic genotype of the virus is also present in Polish stud farms. Such a presence suggests that the future emergence of EHM in Poland is probable.
    BMC Veterinary Research 05/2015; 11(1):102. DOI:10.1186/s12917-015-0416-7 · 1.74 Impact Factor