Guidance

Vets: testing pigs for endemic disease follow-up

Published 19 June 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 serum (blood) 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 polymerase chain reaction (PCR) testing to detect porcine reproductive and respiratory syndrome (PRRS) genetic material
• request that a 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

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 review farm medicines, including how to prescribe and use them.

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 can tell the farmer about the AHDB Medicine Hub. You could explain how it can help them and encourage them to register if they have not already.

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

Test sample laboratory analysis

Send the test sample for analysis to a laboratory for analysis. A farmer will not be eligible for funding unless the laboratory meets at least one of these specifications:

• ISO/IEC 17025 accredited
• UKAS accredited (UK accredited) for an enzyme-linked immunosorbent assay (ELISA) or PRRS polymerase chain reaction (PCR) test

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

Based on the vaccination status of the herd in review, and the relevant test results in both the review and follow-up, you must give the tested herd a PRRS disease status as follows: 

• non-vaccinated, oral fluid ELISA negative, serum ELISA negative – Status 1
• non-vaccinated, oral fluid ELISA negative, serum ELISA positive – Status 4
• non-vaccinated, oral fluid ELISA positive, serum PCR negative – Status 1
• non-vaccinated, oral fluid ELISA positive, serum PCR positive, ORF5 modified live virus (MLV) only positive – Status 2
• non-vaccinated, oral fluid ELISA positive, serum PCR positive, ORF5 wild type (WT) PRRS 1 positive – Status 3
• non-vaccinated, oral fluid ELISA positive, serum PCR positive, ORF5 WT PRRS 1 plus MLV or recombination positive – Status 4
• non-vaccinated, oral fluid ELISA positive, serum PCR positive, any ORF5 PRRS 2 positive – Status 4 (note this result will be reported by the laboratory to Animal and Plant Health Agency (APHA) /Department for Environment Food and Rural Affairs (Defra)
• vaccinated, oral fluid ELISA positive, serum PCR positive, ORF5 MLV only positive – Status 2
• vaccinated, oral fluid ELISA positive, serum PCR positive, ORF5 WT PRRS 1 positive – Status 3
• vaccinated, oral fluid ELISA positive, serum PCR positive, ORF5 WT PRRS 1 plus MLV or recombination positive – Status 4
• vaccinated, oral fluid ELISA positive, serum PCR positive, any ORF5 PRRS 2 positive – Status 4 (this result will be reported by the laboratory to APHA/Defra)

The farmer will not be able to complete a claim without this herd disease status. You must include this status in the written report and on the summary sheet.

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 if required
• 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

The Department for Environment, Food & Rural Affairs (Defra) and 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 review or follow-up took place. It should be a separate document.

The summary must include:

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