Form

Test to exclude West Nile Virus in Horses

Published 28 October 2024

© Crown copyright 2024

This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.

Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned.

This publication is available at https://www.gov.uk/government/publications/horses-west-nile-virus-test-wnv02/test-to-exclude-west-nile-virus-in-horses

Private Veterinary Surgeons (PVS) can request tests for West Nile fever (WNF) without an APHA investigation.

The Testing To Exclude (TTE) scheme can only be used when disease is very low on the differential list and not suspected, but the PVS  wants to exclude disease as a differential diagnosis.

Official restrictions are usually not applied during TTE. However, if test results suggest disease is present, APHA will initiate an official investigation and may impose restrictions. The holding and PVS should consider any voluntary restrictions while testing takes place.

The PVS must agree to meet all costs associated with the collection, submission and carriage of samples to APHA Weybridge and all the laboratory test costs.

You must immediately report any clinical changes for the suspician of WNF or other notifiable diseases.

1. Contact APHA before you submit samples

The PVS must contact the APHA helpline to discuss the case with the duty vet before submitting any samples.

Call the APHA helpline on:

  • 03000 200 301 if you’re in England
  • 03003 038 268 if you’re in Wales
  • your local Field Services Office if you’re in Scotland

If WNV is still not suspected after the discussion, but the PVS wants to exclude WNV as a differential diagnosis, the duty vet will provide the PVS with an authorisation reference number to proceed with the TTE submission.

However, an APHA investigation will be initiated if WNF is suspected given the epidemiological evidence or clinical signs.

2. Submitting samples

If the duty vet agrees, the PVS can submit samples through the TTE scheme.

  1. Read the guidance on how to submit samples for WNV testing. The PVS is responsible for collecting and submitting the samples. All the samples must be clearly labelled.
  2. Fully complete the West Nile Virus submission form. For a TTE the sample will be initially tested by an IgM Ab detection ELISA (TC0868). If both tests (TCO868 and TCO869) are required this should be noted on the submission form. 
  3. Ensure that the case authorisation reference number provided by the APHA duty vet is clearly written and visible on the outer packaging.
  4. Submit the form to APHA Weybridge with the samples, ensuring the samples are packaged in an approved manner.
  5. During laboratory open hours you will also need to phone and email the lab with the expected time of arrival of the samples. Outside these hours the APHA duty vet is responsible for contacting APHA Weybridge.

2.1 Information to include in the email

Include the following information in the email:

  • case authorisation reference number
  • owner and farm or holding name
  • number of epidemiological groups sampled
  • number of samples submitted
  • expected date and time of arrival of the submission

2.2 Contacting the lab

3. Laboratory open hours

  • Monday to Thursday: 9am to 5pm
  • Friday: 9am to 4pm

The testing laboratory cannot be contacted outside of these hours, or on Bank Holidays.

4. Turnaround times

For samples received during laboratory open hours, results will be available within 48 hours of receipt.

Samples received when the laboratory is closed will begin testing at 9am the next working day. Results will be available with 48 hours.

If you contact the lab for your results this may cause a delay.

Back to top