Equine Arteritis Virus (EAV)

Test codes:
S0066 - Ultrasensitive qualitative detection of equine arteritis virus by reverse transcription real time polymerase chain reaction
P0013 - Equine respiratory panel (includes equine arteritis virus and other pathogens)
P0024 - Equine breeding panel (includes equine arteritis virus and other pathogens)

Equine arteritis virus (EAV) is a positive stranded RNA virus in the family Arteriviridae, order Nidovirales, and infects horses worldwide. Sporadic respiratory disease and sudden death in foals, abortion in mares, and mild or subclinical infections in adult horses (Del Piero, 2000) have been described resulting from this infection. Adult stallions may become chronically infected; they can become a reservoir and spread the virus via their semen (Timoney and McCollum, 1993).

Clinical signs of EAV infection include depression, anorexia, jaundice, rash, nasal discharge, cough, swelling of the lower limbs, scrotum or mammary gland, periobital swelling and conjunctivitis (pink eye). Mares and geldings eliminate infection within 21 to 30 days. However, 30-60 % of infected stallions become carrriers and shed the virus in their semen.

Only one serotype of EAV is reported, but there are several strains that differ in their virulence and neutralization phenotype. Novel genetic variants of EAV can arise during persistent infection of stallions, and the continued movement of persistently infected stallions and infective semen have created a requirement for rapid, sensitive and specific tests to detect EAV.

The presence of EAV in the semen of carrier stallions can be detected by virus isolation in cell culture or by test breeding of stallions to susceptible mares but both techniques are time consuming, expensive and cumbersome (Timoney and McCollum, 1993; Mann, 1997,1998). Serologic detection of this virus is not reliable since the serologic response of individual horses to EAV may vary with the infecting virus strain and duration of infection (MacLachlan et al., 1998). Molecular detection of EAV is a fast, specific and reliable method for determining EAV infection status.

Utilities:

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

References:
Del Piero, F. (2000) Equine Viral Arteritis, review article. Vet. Pathol. 37:287-296.
MacLachlan, N.J., Balasuriya, U.B., Hedges, J.F., Schweidler, T.M., McCollum, W.H., Timoney, P.J., Hullinger, P.J. and Patton, J.F. (1998) Serologic Response of Horses to the Structural Proteins of Equine Arteritis Virus. J Vet Diagn Invest. 10:229-36.
Mann, A.W. (1997) Addressing Equine Viral Arteritis in the United States. Proc. Annu. Meet. U.S. Anim. Health Assoc., pp. 259–264.
Mann, A.W. (1998) Equine Viral Arteritis. Proc. Annu. Meet. U.S. Anim. Health Assoc., pp. 314–316.
Timoney, P. J. and W. H. McCollum (1993) Equine Viral Arteritis. Vet. Clin. N. Am. Equine Pract. 9:295-309.

Specimen requirements: Nasopharyngeal swab, or 1 ml whole blood in EDTA (purple top) or ACD (yellow top) tube, or 1 ml semen, or 1 ml tissue, shipped overnight at room temperature; or 1 ml frozen semen or 1 ml frozen 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 reverse transcription real time PCR

Normal range: Nondetected