- Testing for exclusion of notifiable avian disease
Testing for exclusion of notifiable avian disease
Defra, Scottish Government, Welsh Government and APHA have agreed to offer testing for exclusion of notifiable avian disease (NAD) to poultry keepers.
The Notifiable Avian Disease Control Strategy for Great Britain states that a private veterinary surgeon (PVS) may ask APHA to attend a consultation case where NAD (avian influenza and Newcastle disease) is very low on the differential diagnosis list. APHA would then either rule out suspicion of notifiable disease on clinical grounds, or begin an official investigation and impose restrictions if disease is suspected.
This page explains how a PVS should proceed if they wish to carry out testing for these diseases without an APHA investigation taking place.
The APHA service ran for a year until May 2015 as a pilot which was successful and is now continuing on an ongoing basis, enabling PVSs to pay APHA to test samples where the APHA duty vet agrees that notifiable disease is not suspected. No official restrictions will usually be applied, although the farm should consider, with their PVS, any voluntary restrictions.
APHA will charge the full cost for testing. The focus of the pilot was on chickens and turkeys, and this remains unchanged for the ongoing service. The service may be extended in future to non-galliformes. If the service is to be extended further detailed information will be provided.
Veterinary Record letter
Gibbens N et al. (2014) Surveillance: Testing for exclusion of notifiable avian disease (letter)
Veterinary Record 2014; 174:534-535 doi:10.1136/vr.g3412 http://veterinaryrecord.bmj.com
- Sample collection and submission
- Further information on testing
- Roles and responsibilities for NAD exclusion testing requests
- Further information on avian influenza and Newcastle disease
Sample collection and submission
1. The PVS is responsible for collecting and submitting the samples for testing.
3. Only fine-tipped wire stemmed sterile dry swabs must be used. Wooden or plastic stemmed swabs or swabs in charcoal or other transport medium must not be used as these can interfere with the test.
4. A prescribed number of oro-pharyngeal and cloacal swabs must be submitted, ideally taken from birds in the acute phase of infection which have been sick for up to five days.
5. Unless decided otherwise, the number and type of samples that must be collected from birds in each epidemiological group (i.e. birds sharing the same air space) will be as follows:
a. 20 cloacal swabs
b. 20 oro-pharyngeal swabs.
6. It may be possible to submit fewer samples where there are less than 20 birds in an epidemiological group, but this must be agreed with the APHA duty vet in advance.
7. A minimum sampling protocol will incorporate five birds, resulting in the testing of 1 pool of cloacal swabs and 1 pool of oro-pharyngeal swabs.
8. Samples should be packaged in an approved manner and submitted to the address below, ensuring that the unique submission authorisation reference number provided by the APHA duty vet is clearly and legibly written on the outer packaging.
9. Samples must be received at the APHA Weybridge laboratory by 09:00 on Friday (or on the working day before a public holiday) to be eligible for the in-hours testing charge rate.
Further information on testing
1. Samples may be tested for avian influenza (AI) or APMV-1/Newcastle disease (ND) or both AI and ND, by RRT-PCR.
2. Results will usually be available within 48 hours after sample receipt. Samples may also be submitted to the laboratory over a weekend/public holiday with a request for testing to start on the next working day. In such cases the test turnaround time will start from 09:00 on the next working day, and results will usually be available within 48 hours from that time.
3. The PVS must ensure that their requirements relating to testing and reporting are clearly completed on the ‘Exclusion Testing for NAD’ submission form, specifically:
a. Test(s) required (select one only):
i. AI PCR
ii. ND PCR
iii. AI & ND PCR
b. Testing service required (select one only):
i. Standard (in-hours)
ii. Out-of-hours service
c. Method and details for reporting (select one only):
i. Fax (and provide fax number).
ii. Email (and provide email address).
4. Samples will be pooled for testing i.e. 20 swabs = 4 pools of five swabs = 4 PCR tests. As sampling requires collection of both cloacal swabs and oro-pharyngeal swabs, each epidemiological group would typically require eight PCR tests.
5. Test prices are available from GOV.UK.
6. Normal working hours for the testing laboratory are:
a. Monday – Thursday: 09:00 – 17:00.
b. Friday: 09:00 – 16:00.
c. The testing laboratory cannot be contacted outside of these hours, or on Bank Holidays.
Please do not contact the laboratory by telephone or email asking for test results. All testing and reporting will be performed within the stated test turnaround times wherever possible. Contacting the lab may delay the testing/reporting process.
Roles and responsibilities for NAD exclusion testing requests
Role of submitting PVS
1. The PVS must contact the APHA Field Services office responsible for the premises where the birds are located to discuss the incident with the APHA duty vet prior to the submission of samples. Contact numbers are available on GOV.UK.
2. If after the discussion NAD is not suspected, but PVS wishes to exclude NAD from differential diagnosis they can proceed with the submission.
3. The PVS must agree to meet all costs associated with the collection and submission/carriage of samples to APHA Weybridge and all of the laboratory test costs.
4. The PVS must submit the samples to APHA Weybridge accompanied with the fully completed VLA2 form and the ‘Exclusion Testing for NAD’ continuation sheet, being sure to include:
a. The case authorisation reference number issued by the APHA duty vet.
b. Requests relating to testing and reporting, as outlined in part 2 of the ‘further information on testing’ section above.
5. During normal working hours the PVS must inform APHA Weybridge of the expected time of arrival for the samples by phoning the Virology office on 01932 357652 and sending an email to: email@example.com.
This email from the PVS must include the following:
(i) Case authorisation reference number supplied by the APHA duty vet.
(ii) Owner and farm name.
(iii) Number of epidemiological groups sampled.
(iv) Number of cloacal swabs and oro-pharyngeal swabs submitted.
(v) Expected date and time of arrival of the submission.
Outside normal working hours the APHA duty vet is responsible for contacting AHLA Weybridge.
6. The PVS must ensure that all samples are packaged in an approved manner and arrange carriage/despatch to APHA Weybridge.
7. If there is any change in the clinical picture that could suggest a notifiable disease the submitting PVS must report this immediately to the APHA duty vet.
Role of APHA duty veterinarian
1. Discuss incident with submitting PVS.
2. If NAD is suspected proceed with standard report case procedures.
3. If agree that NAD is not suspected proceed with exclusion testing process.
4. Issue unique case authorisation reference number to submitting PVS.
5. Advise PVS if necessary that relevant information about the Exclusion Testing for NAD process is available on the website, including the required submission forms (VLA2 and ‘Exclusion Testing for NAD’ forms).
6. Advise PVS that the laboratory at APHA Weybridge should be contacted by telephone and email to provide submission information – as described in paragraph 5 of role of submitting PV)’ above.
Irvine RM (2013) Recognising avian notifiable diseases 1. Avian influenza. In Practice 35:426-437.
Irvine RM (2013) Recognising avian notifiable diseases 2. Newcastle disease. In Practice 35:518-523.
Irvine RM (2013) Recognising avian notifiable diseases: 3. Clinical disease investigations and differential diagnoses in poultry. In Practice 35: 597-600.