Equine Herpesvirus Type V (EHV-5)

Test code: S0075

Test name: Qualitative detection of Equine Herpesvirus Type V by polymerase chain reaction

Equine herpesvirus type 2 (EHV-2) and type 5 (EHV-5) were recently re-classified as members of the gamma herpesviridiae family (Browning and Studder, 1987; Telford et al., 1993). Unlike EHV-2, which is widely spread in horse populations worldwide, EHV-5 has so far only been isolated in a few countries, including Switzerland, Germany, Australia and New Zealand. In Australia, EHV-5 was originally discovered in horses suffering from upper respiratory disease (Browning and Studdert, 1987). A difference in the prevalence of EHV-2 and EHV-5 was also observed in Australia where 31 % of the tested horses were positive to EHV-2 while only 16 % were positive to EHV-5.

Studies have shown that EHV-5 infection is very common in young horses and EHV-5 infections persist in young horses for at least several months. However, EHV-5 is not specifically associated with respiratory disease. In contrast, EHV-2 is less commonly isolated from young horses and its detection is associated with the occurrence of mild respiratory disease.

Serological separation of EHV-2 and EHV-5 is very difficult because of the high degree of similarity in their protein sequences. Reliable differentiation of EHV-5 and EHV-2 relies on molecular detection methods. PCR is the most sensitive and specific technique for detection of each of these viruses.

Utilities:

• Confirm the disease causing agent
• Shorten the time required to confirm a clinical diagnosis of EHV-5 infection
• Ensure that horse populations are free of EHV-5
• Early prevention of spread of this virus
• Minimize personnel exposure to this virus
• Safety monitoring of biological products that derive from horses

References:
Browning, G.F. and Studdert, M.J. (1987) Genomic heterogeneity of equine betaherpesviruses. J. Gen. Virol. 68: 1441-1447.
Telford, E.A.R., Studdert, M.J., Agius, C.D., Watson, M.S., Aird, H.C. and Davison, A.J. (1993) Equine herpesviruses 2 and 5 are gamma-herpesviruses. Virology 195: 492-499.

Specimen requirements: 1 ml whole blood in EDTA (purple top) or ACD (yellow top) tube, or pharyngeal or nasal swab, or tissue, shipped overnight at room temperature; or tissue shipped frozen.

For specimen types other than those listed here, please call to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative PCR

Normal range: Nondetected