Asieh Fatemi Esfedan - Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
Bahador Sarkari - Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran - Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Fataneh Mikaeili - Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.

Background: Cystic echinococcosis (CE), known as hydatid cyst, is a zoonotic parasitic infection caused by the larval stage of Echinococcus granulosus (E. granulosus). Antigen B, the major component of hydatid cyst fluid, is encoded by members of a multigene family. The present study aimed to evaluate the genetic diversity of the gene encoding antigen B۸/۱ (EgAgB۸/۱) among the main intermediate hosts of E. granulosus. Methods: Twenty-eight hydatid cyst isolates (۱۰ sheep, ۹ human, and ۹ cattle) were collected in Fars province, Iran. DNA was extracted from each cyst and PCR, followed by DNA sequencing was used to identify potential EgAgB۸/۱ sequence variation and polymorphism. A phylogenetic tree was constructed using MEGA ۷.۰ software and the maximum likelihood method. Results: Using EgAgB۸/۱ primers, an approximately ۳۱۵ bp band was amplified from all the isolates. The PCR products were sequenced, and the sequences were deposited in GenBank (accession numbers, KY۷۰۹۲۶۶-KY۷۰۹۲۹۳). The polymorphism variation among the isolates was ۰.۰, while intra-species variation within the isolates and related sequences in GenBank was ۰.۵-۱%. Analysis of the phylogenetic tree revealed that the isolates from humans, sheep, and cattle all cluster in one group and are homologous to the EgAgB۸/۱ M۱ allele. Conclusions: Findings of this study revealed close similarity between the EgAgB۸/۱ of human, sheep, and cattle E. granulosus isolates. However, differences were found between the EgAgB۸/۱ sequences in our study and those reported from other CE endemic areas. Whether such similarities and differences exist in other subunits AgB subunits require further study.

Antigen B۱, Fars province, Genetic Variation, Iran.