Equine Herpesvirus Type II (EHV-2)

Test code: S0072

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

Equine herpesvirus type II (EHV-2) is a DNA virus belonging to the gammaherpesvirus family. This virus infects B cells and is related to other lymphotropic herpesviruses such as Epstein-Barr virus (EBV, which causes glandular fever) and human herpesvirus type 8 (HHV-8), also known as Kaposi's sarcoma herpesvirus.

EHV-2 is highly prevalent (approaching 100%) in horse populations (Borchers et al., 1999) and has been proposed to cause, or to be a predisposing factor for, a number of distinct syndromes. These include “loss of performance”, conjunctivitis (Kershaw et al., 2001) and respiratory tract disease. EHV-2 has also been suggested as a possible transactivating factor triggering or exacerbating EHV-1 or EHV-4 reactivation and disease. While the association of EHV-2 with particular diseases is subject to debate, it is clear that this virus has the potential to escape and subvert host immune responses.

Serological detection of EHV-2 is of limited use to determine the re-activation of this herpes virus. EHV-2 can remain latent in affected animals while shedding at levels adequate to infect other horses. Culture identification of EHV-2 is slow and has low sensitivity. Molecular detection of EHV-2 by PCR is the most sensitive, specific and accurate tool in assessing the infectivity of an affected horse.

Utilities:

• Confirm the disease causing agent
• Shorten the time required to confirm a clinical diagnosis of EHV-2 infection
• Ensure that horse populations are free of EHV-2
• Early prevention of spread of this virus
• Minimize personnel exposure to this virus
• Safety monitoring of biological products that derive from horses

References:
Slater, J. D., Borchers, K., Thackray, A. M. and Field, H. J. (1994) The trigeminal ganglion is a location for equine herpesvirus 1 latency and reactivation in the horse. J. Gen. Virol. 75: 2007–2016.

Specimen requirements: 1 ml whole blood in EDTA (purple top) or ACD (yellow top) tube, or nasopharyngeal swab, or bronchoalveolar lavage, 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