Prevalence of PRRS virus in Wallonia (Belgium)

Abstract

Porcine reproductive and respiratory syndrome (PRRS) causes major economic losses in pig farms. In different parts of the world, there is growing consensus that PRRS virus (PRRSv) eradication should be performed on a regional basis, particularly in low density areas of pig production. The objective of the present study was to evaluate the apparent prevalence of PRRSv in Wallonia, a low density area of pig production (0.05 pig farms/km²). A phone survey was addressed to 173 of the 276 Walloon breeding pig owners. One hundred and thirty‐two farmers answered the questionnaire and serological tests were performed in 113 herds. If no vaccination was carried out on sows or on piglets, an Elisa test was performed on 10 breeding and/or 5 feeder pig serum samples collected between November 2011 and December 2012. An individual result was considered negative if the s/p ratio was <0.4; a herd was considered positive if an s/p ratio ≥0.4 was obtained by at least one of its pigs. Globally, at herd level and at animal level, the apparent prevalences were respectively 48% (IC95%: 39 – 57%) and 32 % (IC 95%: 29 – 35%). The present study has shown that half the Walloon breeding pig farms are serologically positive for PRRSv. Such prevalence in an area of low pig production supports the project for a regional PRRS control program