Evaluation of two PCR-based techniques for molecular epidemiology in Finland, a high-endemic area with four sympatric Trichinella species

Trichinella larvae collected from wildlife, domestic and synanthropic anima ls in Finland were identified to species by two molecular techniques: Rando m amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR) and the recently described multiplex PCR. The RAPD-PCR was very sensitive to the su b-optimal preservation muscle larvae and resulting in weak and smeared band s on the gels for such material. However, the same samples yielded easily r ecognizable bands in the multiplex PCR; this latter technique is then recom mended for epidemiological studies, especially when the preservation of the samples is sub-optimal. For larvae in good condition the unequivocal bands obtained by multiplex was the easiest identifiable. Four species of Trichi nella were identified in the material: T spiralis, T, nativa, T britovi, an d T. pseudospiralis. Trichinella britovi is a new record for Finland, and T . pseudospiralis is a new record for Northern Europe. Mixed infections betw een T. britovi and T. spiralis, T, nativa and T. spiralis, and between T. b ritovi and T. nativa were detected, this is the first record of a mixed inf ection between T. spiralis and T. nativa in a naturally infected host. Racc oon dogs were the only host species from which all of the four Trichinella species were detected. Trichinella spiralis was found in both domestic anim als and wildlife, but none of the sylvatic Trichinella species were detecte d in domestic pig.