Biological and genetic characteristics of two Trichinella isolates in China; comparison with European species

The most recent taxonomic revision in Trichinella genus included 10 taxa. T richinella spiralis (Ts) is a thoroughly studied species but most of the is olates came from the Europe or American continents. Few information is avai lable from China about the Trichinella isolates and their diversity. In thi s report two Chinese isolates were characterized and compared with European strains. The in vitro release of newborn larvae (NBL) was determined for t he two species. NBI is observed in supernatant of cell culture after adults purification on day 4 post infection (pi) with Ts, and on day 5 pi with Tr ichinella native (Tna). A new parameter was thus proposed to characterize T richinella strains. Restriction fragment length polymorphism (RFLP) of geno mic DNA and random amplified polymorphic cDNA (RAPD) were used to define ge netic variability among different isolates. Species specific pattern could be obtained with RAPD but it was for more difficult to get geographical mar kers for Trichinella using these methods. A low genetic variability in Tric hinella species (i.e a strong "clonality") is suggested.