Risk factors for porcine post-weaning multisystemic wasting syndrome (PMWS) in 149 French farrow-to-finish herds

A cross-sectional study involving 149 farms was carried out in France in 2000 and 2001 to assess the risk factors for post-weaning multisystemic wasting syndrome (PMWS). The farms were divided into three groups according to their current or past PMWS status: CASES (current and typical PMWS), CONTROLS#1 (PMWS-free farms), and CONTROLS#2 (farms which have recovered from PMWS). Two different comparisons were tested: CASES versus CONTROLS#1 and CASES versus CONTROLS#2. In the first comparison, the odds of PMWS were increased when fattening pigs tested positive for parvovirus (PPv) and porcine reproductive and respiratory syndrome (PRRS) virus (OR = 4.4 and 6.5, respectively), when separate vaccines for parvovirus and Erysipela for the gilts versus associated vaccines were used (OR = 2.5), and when on-farm semen collection was used versus all the semen purchased from an insemination centre (OR = 4.6). Large pens in weaning facilities increased the odds of PMWS (OR = 4.1); whereas long empty periods in weaning and farrowing facilities versus shorter (OR = 0.2), regular treatment against external parasites (OR = 0.1), and housing the sows in collective pens during pregnancy versus individual pens (OR = 0.3) all decreased the odds of PMWS. The same kinds of risk factors were found with the second comparison with, in addition, a common pit for several adjacent fattening rooms versus separate pits (OR = 6.7) and a high level of cross-fostering (OR = 5.1). On the other hand, when farms had a self-replacement scheme for the gilts (OR = 0.1), and when vaccination of the sows against E. coli was in place (OR = 0.2), the odds of PMWS were decreased. (C) 2003 Elsevier B.V. All rights reserved.