Guidance

Vets: testing pigs for endemic disease follow-up

Updated 10 October 2024

Applies to England

Testing, sampling and advice

Test type and sampling

Wherever possible, sampling should take place on the date of your first follow-up visit to the farm or as soon as possible after.

Testing in the follow-up is based on blood (serum) sampling.

For herds that tested positive in the review, you must:

• take blood samples from exactly 30 pigs
• send samples to an accredited laboratory for testing
• request pooled polymerase chain reaction (PCR) testing to detect porcine reproductive and respiratory syndrome (PRRS) genetic material
• request that a single positive PCR test be genetically sequenced at open reading frame (ORF) 5 to confirm the type of PRRS detected

For herds that tested negative in the review, you must:

• take blood samples from exactly 30 pigs
• send samples to an accredited laboratory for testing
• request enzyme-linked immunosorbent assay (ELISA) testing to detect PRRS antibodies

You must not:

• pool any of the samples (PCR samples will be pooled at the lab according to their testing protocols)
• take any other kind of sample (only blood (serum) samples are valid for a follow-up)
• request any kind of test other than those noted here which are specific to the herd status in the review

If the farm routinely vaccinates, you should only take samples from vaccinated animals.

Biosecurity assessment

For the farmer to claim funding, you must:

• do a biosecurity assessment
• give an assessment report and score out of 100
• include the score on the summary sheet

The assessment must cover:

• farm characteristics, including farm location, housing type, and housing condition
• purchase of breeding pigs, weaned piglets, and semen
• transport of animals, removal of deadstock, and manure
• feed, water, bedding, and equipment supply
• visitors and workers
• vermin, bird, and wildlife control
• disease management
• farrowing and suckling period
• nursery area or unit
• finishing area or unit
• measures between compartments, working lines and use of equipment
• cleaning and disinfection

You can use free online tools to help you in this assessment. Biocheck.UGent and Combat meet the criteria listed above for PRRS related biosecurity.

Other biosecurity assessment tools may be available. Paid versions of any tool are not funded as part of this service but may be used.

Review medicine usage (optional)

The farmer may ask you to discuss farm medicines.

You could discuss:

• recommendations about medicines used on the farm, including antibiotics and vaccinations
• how and when to use preventative medicines, and how to store them
• the value of testing over treatment and why the right diagnostics can save money

You could tell the farmer about the AHDB Medicine book for pigs.

Test sample laboratory analysis

Send the test samples to a laboratory that is UKAS accredited to ISO/IEC 17025 standards for the type of testing being done: 

• PRRS enzyme-linked immunosorbent assay (ELISA) 
• PRRS polymerase chain reaction (PCR) test  
• Genetic sequencing at open reading frame 5 (ORF5) 

A farmer will not be eligible for funding unless the laboratory meets this specification.

Find a recommended laboratory to test for PRRS in pigs.

Test results

For PCR testing, there will be 6 test results, one from each of the pooled blood samples. If one or more test result is positive, then the herd is considered positive for PRRS genetic material. The results of the ORF5 genetic sequencing tell you what type of PRRS is present in the herd.

For ELISA testing, there will be 30 test results. If one or more test result is positive, then the herd is considered positive for PRRS antibodies.

 For the farmer to be eligible to claim funding, you must:

• discuss the test results and any further action or recommendations with the farmer
• give a positive or negative overall test result to the farmer using the summary sheet

The farmer may want to re-test or do more testing based on the results from the follow-up. These will not be funded under the follow-up scheme. Only one set of endemic disease follow-up testing per herd will be funded in each of the 3 years.

Herd PRRS status

For all valid agreements, including those from before 19 June 2024, you should base the PRRS status on all of the following: 

• the vaccination status of the herd
• the result of the review testing  
• the result of follow-up testing

You must give the tested herd a PRRS disease status as follows.

For non-vaccinated herds

Last review  test result	Follow-up blood (serum) test result	Follow-up ORF5 test result	PRRS disease status
Negative	ELISA negative	Not applicable	Status 1
Negative	ELISA positive	Not applicable	Status 4
Positive	PCR negative	Not applicable	Status 1
Positive	PCR positive	Modified live virus (MLV) only	Status 2
Positive	PCR positive	Wild type (WT) PRRS 1	Status 3
Positive	PCR positive	WT PRRS 1 plus MLV or recombination	Status 4
Positive	PCR positive	PRRS 2	Status 4*

For vaccinated herds

Last review test result	Follow-up blood (serum) test result	Follow-up ORF5 test result	PRRS disease status
Positive	PCR positive	MLV only	Status 2
Positive	PCR positive	WT PRRS 1	Status 3
Positive	PCR positive	WT PRRS 1 plus MLV or recombination	Status 4
Positive	PCR positive	PRRS 2	Status 4*

*Note this result will be reported by the laboratory to the Animal and Plant Health Agency (APHA) / the Department for Environment, Food & Rural Affairs (Defra).

The farmer will not be able to complete a claim without this herd disease status. You must include this status in the vet summary.

PRRS statuses assigned as part of this testing are snapshots in time that provide a baseline or starting status. They do not represent an official accreditation by the government.

What documentation you need to give the farmer

When you have completed the review, the farmer will ask you to give them:

• a written report
• a vet summary

Written report

It should include:

• laboratory test results
• advice or suggested health and welfare actions
• other findings, for example biosecurity recommendations and medicine usage
• actions to address issues from the follow-up – this is likely to be 2 to 3 but can be more or less based on individual needs
• information about other concerns the farmer raised

Defra and the Rural Payments Agency (RPA) will not ask to see the report.

Vet summary

The summary gives the information the farmer needs to make a claim. The RPA may ask to see the summary as evidence that the follow-up took place. It should be a separate document.

We suggest you use our vet summary templates for pig testing. If you choose to use your own summary template to give to the farmer, it must include:

• the species the farmer chose for the follow-up
• the single business identifier (SBI)
• the name of the business where the follow-up took place
• the agreement number
• the date of the vet’s last visit to the farm for the follow-up
• the date samples were last taken for the follow-up
• confirmation the farmer had the minimum number of animals required on the date of the follow-up
• the number of animals samples were taken from
• the vet’s name 
• the vet’s Royal College of Veterinary Surgeons (RCVS) number
• the test results from the initial review
• the herd vaccination status
• the laboratory unique reference number (URN) for the test results
• the number of samples tested
• the disease status category
• confirmation the vet did a biosecurity assessment
• the biosecurity assessment score
• confirmation the vet gave the farmer a written report
• the vet’s signature and date – the signature can be digital or on paper