Echinococcus multilocularis genetic diversity based on isolates from pigs confirmed the characteristic haplotype distribution and the presence of the Asian-like haplotype in Central Europe

Abstract

Introduction: The aim of the study was to determine the genetic diversity of Echinococcus multilocularis in pigs in highly endemic areas in Poland, as well as to attempt to confirm the occurrence and geographical distribution of haplotypes characteristic for these areas, which were previously described on the basis of examination of adult tapeworms isolated from foxes. Material and Methods: Twenty samples of E. multilocularis larval forms were obtained from pigs’ livers in four provinces of Poland. Genetic analyses were conducted on sequences of two mitochondrial genes: cox1 and nad2. Results: Seven haplotypes were found for the cox1 gene (OQ874673–OQ874679) and four haplotypes for nad2 (OQ884981–OQ884984). They corresponded to the haplotypes described earlier in foxes in Poland (some of them differing only in one nucleotide). The analysis showed the presence of the Asian-like haplotype in both the cox1 and nad2 genes. The remaining haplotypes were grouped in the European clade. The geographical distribution of haplotypes identified in the pig samples was noticed to bear a similarity to the distribution of haplotypes previously isolated from foxes in the same regions. Conclusion: The characteristic geographical distribution of E. multilocularis haplotypes in Central Europe (including the presence of the Asian-like haplotype) previously described in the population of definitive hosts (foxes) has now been confirmed by the analysis of samples from non-specific intermediate hosts (pigs).