Neurological disease associated with EHV-1-infection in a riding school: clinical and virological characteristics.
Abstract: An outbreak of neurological disease caused by EHV-1 infection is described with emphasis on diagnosis and prognosis for recumbent horses. In April 1995, an outbreak of the neurological form of Equine herpesvirus type 1 (EHV-1) occurred in a well-managed riding school with 41 horses: 34 horses showed a temperature spike and 20 some degree of neurological signs, of which 10 were nursed intensively in the indoor arena of the riding school for 3 to 20 days, 8 having to be maintained in slings for 2-18 days, while 9 needed bladder catheterisation b.i.d. for 2-16 days. Within the first 3 days, one horse was subjected to euthanasia and another horse died. Postmortem examination revealed a mild vasculitis with perivascular mononuclear cuffing and axonal degeneration in the central nervous system. Clinical diagnosis was confirmed by serology and virology: 28 horses seroconverted in one or more tests during the outbreak, whereas 12 had already high CF and SN titres in the first sample, suggestive of recent infection. Virus was isolated from nasal swabs of 4 horses, and identified as EHV-1 with type-specific monoclonal antibodies. Restriction enzyme analysis revealed that the EHV-1 strains from this outbreak belonged to genome type EHV-1.IP. The electropherotypes were identical to those from another, epidemiologically unrelated, outbreak of neurological disease 2 months earlier. The timing of the temperature spikes and seroconversions indicated that the infection was probably introduced by a horse purchased 3 weeks before neurological signs occurred. At follow-up one year later, the 10 horses that showed mild neurological signs had recovered completely. Of the 8 horses that survived intensive care, 3 had returned to around their former performance level (2 of which had been in slings), while the other 5 had become pasture-sound. At follow-up 4 years later, all pasture-sound horses had been subjected to euthanasia because of persistent mild ataxia and incontinence. In conclusion, the prognosis for recumbent horses due to EHV-1 infection is grave. For virological diagnosis, extensive and strategic sampling of febrile in-contact horses is required, and the EHV-1-specific glycoprotein G (gG) ELISA is a valuable tool for specific serological diagnosis of EHV-1 infection causing neurological disease.
Publication Date: 2001-03-27 PubMed ID: 11266070DOI: 10.1111/j.2042-3306.2001.tb00600.xGoogle Scholar: Lookup
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- Journal Article
Summary
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This research explores a disease outbreak among horses in a riding school caused by the Equine herpesvirus type 1 (EHV-1) infection and studies the clinical and virological components of the disease, including the diagnosis and prognosis for recumbent horses.
Research Context and Objective
- The research describes an outbreak of neurological disease in a riding school with 41 horses, assumed to be caused by the Equine herpesvirus type 1 (EHV-1) infection.
- The main focus of the study was to investigate the clinical manifestations of the disease and identify its potential prognosis, particularly in the case of recumbent or downed horses who were unable to rise to their feet.
Methodology and Findings
- During the outbreak, 34 horses showed a temperature spike and 20 displayed various neurological signs, with 10 requiring intensive care.
- Diagnosis of the disease was confirmed via serology—a test that measures the concentration of antibodies in blood—and virology, studying the characteristics of the virus.
- The virus was isolated from nasal swabs from four horses and was identified to be EHV-1 using particular monoclonal antibodies. Further analysis showed that the EHV-1 strains belonged to the genome type EHV-1.IP.
- The virus associated with the outbreak was observed to be identical to another disease outbreak that had occurred two months earlier; however, the two events were not epidemiologically related.
Prognosis and Follow-up
- One year after the outbreak, horses that displayed minor neurological signs had recovered entirely. However, despite surviving intensive care, only three of eight horses returned to their previous performance levels, with the rest becoming “pasture-sound”—fit for light work or grazing but not for riding or driving.
- After another three years, all pasture-sound horses had to be euthanised due to ongoing light uncoordination (ataxia) and incontinence.
Conclusion and Implications
- The research confirmed the serious prognosis for recumbent horses affected by EHV-1, highlighting the importance of thorough and strategic sampling of febrile horses for effective virological diagnosis.
- The research also suggested the EHV-1-specific glycoprotein G (gG) ELISA test as a valuable tool for the specific serological diagnosis of EHV-1 infection leading to neurological disease.
Cite This Article
APA
van Maanen C, Sloet van Oldruitenborgh-Oosterbaan MM, Damen EA, Derksen AG.
(2001).
Neurological disease associated with EHV-1-infection in a riding school: clinical and virological characteristics.
Equine Vet J, 33(2), 191-196.
https://doi.org/10.1111/j.2042-3306.2001.tb00600.x Publication
Researcher Affiliations
- Animal Health Service, Deventer, The Netherlands.
MeSH Terms
- Animals
- Ataxia / veterinary
- Disease Outbreaks / veterinary
- Enzyme-Linked Immunosorbent Assay / veterinary
- Female
- Herpesviridae Infections / epidemiology
- Herpesviridae Infections / veterinary
- Herpesvirus 1, Equid / isolation & purification
- Horse Diseases / blood
- Horse Diseases / epidemiology
- Horse Diseases / pathology
- Horses
- Male
- Nasopharynx / virology
- Nervous System Diseases / epidemiology
- Nervous System Diseases / veterinary
- Netherlands / epidemiology
- Prevalence
- Recreation
Citations
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