Genetic structuring and differentiation of Echinococcus multilocularis in Slovakia assessed by sequencing and isoenzyme studies

Nucleotide sequencing of the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene and isoenzyme analysis were used to survey the genetic variability in Echinococcus multilocularis populations from Slovakia. A sample of 12 isolates acquired from 10 different districts from red foxes exhibited identical sequences. Compared with the previously described E. multilocularis variants, one base substitution was consistently observed relative to the M1 variant (detected in China, Alaska, North America, Japan) and three base substitutions were recorded relative to the M2 variant (detected in Germany) in the CO1 fragment. These data, along with the recently gathered data from French isolates, are indicative of a genetically unique population occurring in Central and Western Europe. Electrophoretic examination of enzymes produced by 14 gene loci revealed intraspecific polymorphism only with the glucose-phosphate isomerase (two distinct patterns) and the mannosephosphate isomerase (four genotypes composed of three alleles) enzyme systems. To allow a fast species differentiation of E. multilocularis and E. granulosus (specifically, the G7 genotype occurring in Slovakia), discriminative electrophoretic characters between the species were obtained by isoenzyme analysis. Fixed genetic differences between the species were detected in the glucose-phosphate isomerase, esterase and aldolase systems, and partial differences were detected in four additional systems.