Private vets must askapply in writing for permission from the Animal and Plant Health Agency (APHA) before carrying out any tuberculosis (TB) testing.

The only ante mortem tests currently approved for statutory cattle tuberculin (TB) testing of cattle in England are both the:

• comparativesingle intradermal comparative cervical tuberculin skin(SICCT) test (commonly known as the skin test)
• supplementary interferon-yinterferon-gamma (IFN-y) blood test

An understanding of the performance of any diagnostic test under the specific conditions of each country is needed before it can be officially approved for routine veterinary use,use. This usually happens following validation to the standards set out by the World Organisation for Animal Health (WOAH).

Private vets can carry out other non-validated or unapproved TB tests:

• with written permission from the Animal and Plant Health Agency (APHA)
• on an exceptional basis

This applies to any TB test other than the skin and IFN-y tests cited in current EU legislation.

Non-validatedPrivate vets cannot use non-validated or unapproved TB tests cannot be used to replace the current statutory TB testing regime.

What private vets can use private non-validated or unapproved tests can be used for

ThesePrivate testsvets can only beuse usedthese tests to identify additional infected animals in cattle herds with chronicongoing TB breakdowns with lesion and/or positive PCR (or culture) cattle that either:

• have not been resolved by repeated short interval skin testing oror IFN-y parallel testing
• at the point of application, do not qualify for a government-funded supplementary blood test (for example, IFN-y paralleltest) testing.
  carried out by APHA

TheyPrivate vets cannot beuse useda private unofficial test to negate or question positive results to officialanimals testsawaiting onslaughter. animalsThis awaitingis slaughterbecause thatthey are:have reacted to an official TB test, for example:

• skin test reactors
• IFN-y test positive animals

Non-validated or unapproved TB test types

There are 2 categories of unofficial tests for TB in individual cattle herds:

• supplementary diagnostic test kits that have been registered with WOAH-validated kitsas validated for a specific use in cattle, such as the IDEXX ELISA and the Enferplex Enferplex TB antibody antibody test
• novel, semi-experimental assays that have not been validated in cattle, such as the Polymerase Chain Reaction (PCR) on faecal samples and the Actiphage blood assay

The IDEXX ELISA test for M. Bovisbovis

The bovine IDEXX ELISA antibody assay (IDEXX Laboratories, Maine, USA) canmeasures be used to measure circulating antibodies in cattle with advanced M. bovis. ItWOAH ishas approved byit WOAH to supplement the skin test for detection of TB-infected cattlecattle. andWOAH it was added it to WOAH’stheir Register of Validated Diagnostic Kits in June 2012. It’sThis test is performed at APHA Starcross.

Antibody assays are not currently approved for official, regular TB testing of bovine animals in England. However, APHA may use the IDEXX ELISA test as a third-line test in exceptional circumstancescircumstances. inThis forincludes herds that have chronic or persistent TB breakdowns that have not resolved after they have already been through:

• multiple rounds of short interval skin testing
• the IFN-y parallel test

Supplementary IDEXX testing carried out by APHA in England requires prior consent and a written agreement from the owner to allow the removal of any TB seropositive animals,animals. withThe owner is entitled to statutory compensation payments.

The IDEXX ELISA is a relatively simple and inexpensive assay that uses a combination of 2 M. bovis recombinant antigens (MPB83 and MPB70)MPB70). thatIt can provide test results in 2 hours and has:

• a moderate test sensitivity of 65%
• a specificity of 98% in cattle

To achieve maximum sensitivity in this test, private vets must do a prior TB skin testtest. must be performed. APHA thenstrongly requiresrecommends that blood samples for government-fundedprivate IDEXX testing are taken for 10 to 30 days following the skin test.

The Enferplex test for M. Bovisbovis

The Enferplex TB test is another antibodycommercial test for TB inantibody cattletest thatkit wasfrom Enfer Diagnostics validated to WOAH standards morefor recentlysupplementary (Enferuse Diagnostics).in Thiscattle. test achieved WOAH approvaladded andthis wastest addedto their to WOAH’s Register of Validated Diagnostic Kits for the detection of TB in cattle in May 2019.

This test is currently not approvednot bycurrently approved Defra, Scottish and Welsh Governments for official government-funded supplementary TB antibody testing of cattle.cattle Itin England, Scotland or Wales. Private vets can beuse usedit on a private basis in England subject to prior permission from APHA.

The Enferplex TB test is a ‘multiplex’ enzyme immunoassay designed to detect the presence of antibodies to an array of 11 M. bovis antigens. Any antibodies present in serum (and potentially milk) samples are detected simultaneously by a multiplex immunoassay.

Information in the WOAH data sheet indicates:

• a high test sensitivity of 71.4% (non-boosted) and 94.2% (boosted by a prior intradermal injection of tuberculin)
• a specificity of 99.7% for this test using a high specificity setting

AsThe for the IDEXX test, the highest sensitivity of the Enferplex TB test is also dependent on a prior tuberculin skin test,test. whichThis triggers the anamnestic (memory) antibody response in infected cattle. APHA strongly recommends thatprivate vets take blood samples for Enferplex testing of cattle are taken within 10 to 30 days following a skin test.

Conditions for getting permission to test

YouPrivate vets must get permission from APHA before carrying out any private non-validated or unapproved TB test.

APHA will only give permission for the test if the:the herd:

• herd has undergone mandatory IFN-y testing (if the herd is eligible under current Defra policy)
• herd owner has given informed, written consent
• is currently experiencing a TB breakdown and has lost its Officially TB Free (OTF) status
• has not completed all the mandatory statutory testing required for APHA lifting the TB movement restrictions

Informed consent from herd owners

BeforePrivate testing,vets themust get:

• permission from APHA before conducting a private vetunofficial mustblood gettest for TB in cattle
• written informed consent from the herd owner to show they have informedunderstood themcertain that:conditions

These conditions are:

• theDefra testshas are not validated or approved bythe Defratest for routine use in cattle
• the test results may be unreliable and difficult to interpret, meaning the test may not offer any certainty about the animals’ true infection status’status of the animals
• the herd owner is responsible for all removalthe andcosts slaughterof costs,removing unless:
  • the test-positive animals from the herd, unless those animals become positive after a subsequent government-fundedgovernment-funded official TB test test
  • or APHA considers considers it necessary to remove the animals as a direct contactcontacts
• the herd owner must privately slaughter any animal that givestests positive to a private IDEXX ELISA or Enferplex TB test, before APHA will restore the OTF status of the affected herd

Herd owners must also understand that any animal giving a positive result to a private non-validated test or a a WOAH-validated test that is not approved by Defra for routine use will be restricted to the premises for its lifetimelifetime. andThey can beonly moved: move:

• under licence to slaughter directly via a slaughter gathering
• to a veterinary research centre for post-mortem examination
• to an Approved Fishing Unit (AFU)

the herd owner must privately slaughter any animal that tests positive to a private IDEXX ELISA or Enferplex TB test, before APHA will restore the Official TB Free (OTF) status of the affected herd

How to get permission to test from APHA

Private vets must use a PRIV03 application form PRIV03 to apply to APHA for permission to test. ThePrivate formvets must besubmit submittedthe form at least 10 working days before the intended date of sampling

The form must include:

• what animals will be tested
• what type of samples will be taken (for example, blood, milk, faeces, bulk milk)
• what tests will be used and when
• the current known performance of the tests, such as published articles or access to proof-of-concept data
• how the tests will contribute evidence needed to validate the tests (for example, by collaboration with the manufacturer)
• whether a Home Office licence is required and if it has been obtained
• what will be done with the results
• how APHA will be kept informed

Private vets must complete a new PRIV03 application form and submit it to APHA for every subsequent round of private TB blood testing in a herd.

Private vets must also submit a PRIV02 application form PRIV02 if they want to carry out any additional private IFN-y tests in conjunction with the non-validated or unapproved test.

How to send the forms

1. Download the application form.
2. Complete it and save it to your device.
3. Upload it using the contact form.

Engaging with APHA

APHA expects private vets to engage with the test manufacturer so use of the tests can contribute to the evidence needed to validate the tests.

APHA TB diagnostic experts, and the APHA case veterinarian, may be able to offer advice on how to use the tests where APHA has been involved from the outset.

If the herd owner has given written authority to share their information, the APHA case veterinarian will discuss the application with the private vet. This will include the previous test history of the herd and its eligibility for IFN-y testing.

The private vet must give evidence to APHA that shows they have got a Home Office licence has either been obtained or isit’s not needed. For example, blood samples taken at the time of IFN-y testing (or other disease screening) may require a licence for scientific researchresearch. This is unless it was agreed with the Royal College of Veterinary Surgeons (RCVS) that it formed a legitimate part of a disease control intervention that was covered by the Veterinary Surgeons Act.

Test results

The private vet must report test results to APHA immediately after every testing event. The report must also include any planned management of tested animals (for example, by sorting into epidemiological groups).

Under the Tuberculosis in Animals (England) Order 2021 it’s a legal requirement to report suspicion of TB in an animal. This legislation also allows APHA veterinarians to issue a notice that restricts the use of a cow’s milk if the animal is a TB suspect.

What happens if privately-tested animals have positive results

Animals that have tested positive to a non-validated or unapproved test cannot be sold, except to slaughter.

Culling of test-positive animals must be a voluntary decision by the owner,owner. andThey the owner must pay for any associated costs. NoThey compensation will benot available.get any compensation.

Regaining OTF status for TB breakdown herds

Some TB breakdown herds thatmay have completed the normal APHA testing protocols to lift movement restrictions,restrictions butand whichstill contain one or more IDEXX or Enferplex positive animals,animals. These herds will not be able to regain OTF status and move cattle freecannot withoutmove freely (without an APHA licencelicence) until either one of the two following criteriaconditions apply.

Once the herd has regained its OTF status, APHA’s approval to carry out private non-validated or unapproved TB testing will automatically end. A new application willis beneeded required for any further testing.

Milk from test-positive dairy cows

Milk from dairy cows that have tested positive to a non-validated or unapproved test can enter the human food chain.

Milk from these animals will be subject to pasteurisation while the herd is under TB restrictions.

Get help

Get help with bovine TB using the contact form.