Research & Innovation


Photo of Investigation of the epidemiology of PRRS

Ben Williams

Knowledge Transfer Senior Manager

AHDB Pork Knowledge Exchange


Email Ben

T: work 024 7647 8623

Investigation of the epidemiology of PRRS

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Research partners: The Royal Veterinary College (RVC) and the Veterinary Laboratories Agency (VLA)

Sponsor: AHDB Pork-funded studentship (Martina Velasova)

Duration: 2009 – 2011 

Aims and objectives

  • To identify risk factors for active PRRS infection at farm level
  • To evaluate current PRRS surveillance. 

Findings to date

  • The results indicated a prevalence of active PRRS infection of 30.61% in the English pig population with a higher proportion of infected farms located in areas with high pig density
  • In total 43.45% farms reported using vaccination against PRRSV; a higher proportion of farms used live vaccine rather than killed vaccine (82.54% vs.17.46%)
  • Farms were more likely to show evidence of circulating virus if they used live virus vaccine, were located in high pig density areas and had dead pigs collected
  • Farms that weaned pigs at the age of 28 days or later had lower odds of being PRRS positive
  • The probability of an infected farm being detected through passive surveillance was very low
  • Farms which used live virus vaccine had lower probabilities for detection compared to those which did not
  • The results indicate that current control measures are not effective and that surveillance needs enhancement
  • Biosecurity measures and vaccination need to be evaluated to provide effective control and prevention of the PRRS infection
  • Vaccination may minimise the immediate impact seen on farms, but does not prevent virus circulation.

Further information