Pig farming

PRRS: Four Small Letters, One Big Problem!

There are four pillars of PRRS control. You must apply all four in order to successfully control PRRS. In this blog we discuss how diagnostics and monitoring can be used to help with PRRS control.

Pillar Number Three: Diagnostics and Monitoring

PRRS diagnostic testing is a very complicated topic; however, it is useful for producers to understand the basics of techniques involved and why PRRS diagnostics are important.

Firstly why do we need PRRS diagnostics?

  1. If we suspect a PRRS negative herd has become PRRS positive
  2. If we think PRRS might be responsible for disease outbreaks in a known PRRS positive herd
  3. To show where PRRS is circulating and causing problems in an unstable herd
  4. Monitoring changes in PRRS strain

Broadly speaking there are two approaches to determining the presence of PRRS in pigs:


This can be done by looking for the virus in samples of body tissue, blood or saliva (rope testing).


Antibodies show that the pig has been exposed to a PRRS virus. You can detect antibodies in blood or saliva samples.

Positive antibody results could show that:

  1. The pig has been exposed to PRRS disease……. or
  2. The pig has been vaccinated against PRRS……. or
  3. Both of the above!

Negative antibody results can be equally tricky! Negative results could show that:

  1. Pigs are not infected with PRRS……. or
  2. Pigs have not yet had time to produce antibodies against PRRS (antibody production can take a couple of weeks)

PRRS diagnostics can be tricky, and sometimes expensive. But they are a really important tool to understanding the PRRS situation in your herd, and the PRRS situation must first be understood before it can be properly managed.

For further information please contact Zoetis UK Limited, Walton Oaks, Dorking Road, Tadworth, Surrey KT20 7NS. www.zoetis.co.uk Customer Support: 0845 300 8034. Use medicines responsibly (www.noah.co.uk/responsible). Date of preparation: January 2018. AH049/18