First Phylogenetic Perspective on Molecular Epidemiology of Echinococcus granulosus sensu lato in Dogs in Sistan and Baluchestan Province, Southeastern Border of Iran

Background: Echinococcosis or Hydatid disease is a zoonotic disease that is caused by Echinococcus granulosus. The disease is a high public health concern in Iran, but there is little known about the genetic diversity and epidemiology of Echinococcus spp. in Iranian shepherd dogs. Materials and Methods: Fifty shepherd dogs were investigated for the adult worm of E. granulosus from May ۲۰۲۰ to April ۲۰۲۱ in Sistan and Baluchestan Province, the southeastern border of Iran. DNA extraction of samples and amplifying was done, and sequence analysis of mitochondrial genes (Cox۱ and Nad۱) was performed. Results:Out of ۵۰ shepherd dogs, ۱۱ cases (۲۲%) were infected with E. granulosus. No significant difference was observed regarding demographic factors (P>۰.۰۵). The phylogenetic analyses of Cox۱ and Nad۱ sequences demonstrated G۱ genotype (sheep strains) in all isolates. Based on sequence analyses, a low (Cox۱, Hd [haplotype diversity: ۰.۲۰۰; Hn [number of haplotypes]: ۲) to moderate (Nad۱, Hd: ۰.۵۳۳; Hn: ۴) genetic (haplotype) diversity of E. granulosus G۱ genotype and low nucleotide diversity (π: ۰.۰۰۰۵۲-۰.۰۰۲۴۳) were observed. Conclusion: The first identification of a sheep strain (G۱) in the final host in Sistan and Baluchestan Province indicates that potential intermediate hosts play a secondary role in preserving the biology of the dog-sheep cycle. The present study’s findings enrich our knowledge about the prevalence of E. granulosus, the classification of strains, and the genetic diversity of the parasite in Iranian herding dogs. This information helps develop strategies and programs for monitoring and controlling infection in stray dogs in the region

Keywords:

Echinococcus granulosus , shepherd dogs , G۱ , Molecular epidemiology , Sistan and Baluchestan