Genotyping of Echinococcus granulosus Specimens Isolated from Dogs in Southeastern Iran

Cystic echinococcosis is an important zoonotic disease caused by the larval stage of Echinococcus granulosus and remains endemic in Iran. Identification of circulating genotypes in definitive hosts is essential for understanding local transmission patterns and supporting molecular epidemiological surveillance (۱). A total of ۲۶۰ fecal samples were collected from owned, stray, and shelter dogs in Kerman, Zabol, and surrounding areas in southeastern Iran. Samples were examined microscopically for taeniid eggs, and DNA was extracted from microscopically positive samples. Polymerase chain reaction (۲) assays targeted an approximately ۴۵۰ bp fragment of the mitochondrial cox۱ gene and an approximately ۴۶۰ bp fragment of the nuclear ITS۱ region. Amplicons were sequenced and analyzed using BLASTn and phylogenetic approaches to determine genetic identity and relationships (۳). Among the ۲۶۰ samples examined, ۱۷ contained taeniid eggs and/or cestode proglottids, and ۱۳ samples (۵%) were confirmed by PCR as E. granulosus. Clear single amplicons were obtained for both markers. BLASTn and phylogenetic analyses demonstrated that all isolates belonged to E. granulosus sensu stricto (G۱–G۳ complex). The cox۱ sequences showed high similarity to reference strains (۹۸.۰۷%–۹۹.۷۶%), indicating marked mitochondrial homogeneity. In contrast, ITS۱ sequences showed greater variability (۹۷.۷۱%–۹۹.۷۵%) and were distributed into shallow subgroups related to isolates from neighboring endemic regions (۲).The coexistence of mitochondrial homogeneity and moderate nuclear variation reflects the established genetic structure of the E. granulosus sensu stricto(s.s.) population in southeastern Iran. It supports the predominance of the G۱–G۳ complex in this region.

کلیدواژه ها:

dog ، Echinococcus granulosus Genotyping ، Cystic echinococcosis Southeastern Iran