Diagnosis and/or viral detection allows owners and management of horse oriented facilities to make decisions surrounding the implementation of vaccination protocols and management practices to minimize risks to their existing animals and the importation of animals from high risk areas where WNV is considered endemic [please go here].  It is important to consider the following points when testing existing animals:

• The first step in decision making surrounding diagnosis and testing is made based on the presence of clinical signs of WNV.  For clinical signs of WNV [please go here].

• Laboratory procedures are necessary to confirm the presence of WNV due to the subclinical nature of many WNV infections and the similar symptomatology of WNV encephalomyelitis to other equine neurological syndromes. [2]

• Confirmation of WNV infection can be made directly by identification of the virus or indirectly by testing for antibodies in clinical specimens which include, postmortem tissues, cerebrospinal fluid, whole blood or serum. [2]

• Detection of WNV in field cases in horses is hampered by the typically short duration and low level of the viraemia in horses. Negative virus detection test results should thus never be regarded as evidence of absence of WNV [2].