An outbreak of trichinellosis in farmed wild boar in Finland

Nine farmed wild boar out of 25 slaughtered from a single farm were condemn ed at meat inspection because of trichinellosis. With RAPD-PCR, Trichinella spiralis was identified in all positive wild boar. Out of the available se rum samples (n=7), all wild boar which had failed the meat inspection showe d seroconversion in ELISA and Western blotting, as did one additional anima l which had passed the inspection. The animals became infected during an in vasion of rats from an improperly closed dump near the farm. Unfortunately, by the time trichinellosis was discovered in the wild boar, the invasion h ad already been brought under control; thus, no samples from rats were avai lable. However, having lived through the rat invasion was shown to be a ris k factor for trichinellosis in wild boar (relative risk, RR=6.3). In wildli fe samples from surrounding areas, sylvatic trichinellosis was found to be very common (74%; n=19 red foxes). Intriguingly, the prevalent species in t richinella-positive foxes differed from that in wild boar, Trichinella nati va and T. spiralis being found in 12 foxes and in one fox, respectively.