Special Precautions/Comments:

N.B. Please provide a detailed travel history.

CSF samples will also be accepted if accompanied by a blood serum sample.

(Urine samples will be accepted for WNV RT-PCR only).

Method: Enzyme immunoassay (EIA) for the determination of West Nile Virus IgG and IgM antibody levels. Real-time polymerase chain reaction (RT-PCR) for the detection of West Nile Virus DNA. Calibration: – EQA scheme: – IQC: –

Interpretation: Results will be reported as DETECTED (positive) or NOT detected (negative).  A negative PCR result does not exclude previous infection. Clinical comments will be provided based on patient history.

For further information contact UKHSA Porton Down, Rare and imported pathogens laboratory (RIPL).

Additional Information:

Background information: West Nile Virus (WNV) is caused by a viral infection transmitted by Culex mosquitoes between birds, horses and humans. It is non-endemic to the UK and there are currently no reported cases of locally-acquired infection occurring. Although Culex mosquitoes have been reported on occasion in the South East (North Kent, Essex coastline), which may raise the risk of WNV being brought to the UK.

80% of patients with WNV will present as asymptomatic. Around 20% of patients will present with West Nile Fever, a mild flu-like illness. Less than 1% will go on to develop more serious illness, such as encephalitis, meningitis or meningo-encephalitis, this is more likely in patients over 50 years of age.

WNV should be considered for patients who have recently returned from endemic areas and are presenting with febrile or acute neurological illness, this pertains to regions of Southern and Eastern Europe, Africa or North America. WNV should also be considered for patients who have recently visited areas around the Thames estuary (as previously mentioned).