LIMITED RANGE OF GENETIC-VARIATION IN ECHINOCOCCUS-MULTILOCULARIS

DNA sequencing of 1.3 kb of rDNA containing both internal transcribed spacers (ITS1, ITS2) and adjoining rRNA coding regions in each of 11 E chinococcus multilocularis isolates from Germany, Japan, and Alaska re sulted in identical nucleotide sequences except for a single polymorph ic locus 54 bp upstream of the 3' end of the 18S coding region, separa ting Eurasian isolates from an Alaskan isolate. The same base substitu tion was found in each of 2 additional isolates from Alaska. The distr ibution of the resulting genotypes with regard to their origin is high ly significant (>99.9%) and corresponds to the traditional subspecies Echinococcus multilocularis multilocularis and Echinococcus multilocul aris sibiricensis.