Relationship between fumonisin contamination of feed and mystery swine disease. A case-control study.

Fumonisin is a recently identified mycotoxin that has been shown to be the cause of pulmonary edema disease in swine and leukoencephalomalacia in horses. Mystery Swine Disease (MSD), is an economically devastating disease complex of unknown etiology that has been reported to have occurred in several swine producing states since 1988. To determine the relationship between MSD and fumonisin, a case-control study was carried out in Illinois in mid-1990. Feed samples collected from 12 case and 9 control farms were analyzed for fumonisin. Sera from swine on all farms was screened for titers against encephalomyocarditis (EMC) virus and concentrations of alpha-1 acid glycoprotein (an acute phase reactive protein). Fumonisin concentrations greater than or equal to 20 ppm were found on 1 control farm (1/9) and 8 case farms (8/12). Titers against EMC virus (greater than or equal to 1:16) were found on 5 control farms (5/9) and on 6 case farms (6/12). Farms with greater than or equal to 20 ppm fumonisin in the feed were at significantly increased risk (OR = 11.2, Fisher's exact test p = 0.037) for MSD. Furthermore, the pi2 test for trend was (p = 0.017), meaning that as the level of fumonisin in the feed increased, the risk of MSD also increased. The presence of EMC virus titers in the sow herd was not a significant risk for MSD (OR = 1.25, Fisher's exact test p = 0.75). Alpha-1 acid glycoprotein concentrations obtained from a 2-week old nursing pigs differed significantly (p = 0.0005) between MSD case and control herds.