Preliminary investigation of heat shock protein 90 gene diversity in Echinococcus granulosus sensu lato: a potential nuclear marker for species identification.

Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus sensu lato (s.l.), remains a significant zoonotic parasitic infection worldwide. This study provides a preliminary investigation of the nuclear Hsp90 gene diversity within the E. granulosus s.l. complex to evaluate its potential use for species identification. Forty-nine DNA samples of the G1 genotype from human and animal CE cysts, two G3 genotype samples, one of Echinococcus ortleppi, four of Echinococcus canadensis (G7), and four samples of other Taenia species (Echinococcus multilocularis, Taenia hydatigena, Taenia pisiformis, and Taenia ovis) were analyzed. Four primer pairs were designed to amplify the Hsp90 gene, followed by PCR amplification, DNA sequencing, and phylogenetic analysis. Successful amplification and sequencing of nearly the entire Hsp90 gene revealed a single nucleotide polymorphism (SNP) at position 222 conserved across all genotypes. Notably, significant genetic variations were observed between E. ortleppi (G5 genotype) and E. canadensis (G7 genotype) compared to E. granulosus sensu stricto (G1 and G3 genotypes). Phylogenetic analysis confirmed clustering consistent with established taxonomic relationships, with G1 and G3 forming a cluster, and G5 and G7 forming a distinct group. The findings suggest that the nuclear Hsp90 gene could be used as an additional marker for species-level differentiation within the E. granulosus s.l. complex.