Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 19 2 2024 06 09 140 152 Davood Anvari 1. Student Research Committee, Mazandaran University of Medical Science, Sari, Iran 2. Toxoplasmosis Research Center, Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran 3. Department of Parasitology and Mycology, Faculty of Medicine, Iranshahr University of Medical Sciences, Iranshahr, Iran Shirzad Gholami Toxoplasmosis Research Center, Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Adel Spotin Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran Seyed Abdollah Hosseini Toxoplasmosis Research Center, Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Ahmad Daryani Toxoplasmosis Research Center, Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Shahabeddin Sarvi Toxoplasmosis Research Center, Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Mohammad Reza Narouei Faculty of Veterinary Medicine, University of Zabol, Zabol, Iran Mona Hosseini Faculty of Veterinary Medicine, University of Zabol, Zabol, Iran Abolghasem Siyadatpanah Infectious Diseases Research Center, Gonabad University of Medical Sciences, Gonabad, Iran 2021 06 15 2024 06 09 Background: Current study was designed to provide a better insight into the circulating genotypes, genetic diversity, and population structure of Echinococcus spp. between southeast of Iran and Pakistan. Methods: From Jun 2020 to Dec 2020, 46 hydatid cysts were taken from human (n: 6), camel (n: 10), goat (n: 10), cattle (n: 10) and sheep (n: 10) in various cities of Sistan and Baluchestan Province of Iran, located at the neighborhood of Pakistan. DNA samples were extracted, amplified, and subjected to sequence analysis of cox1 and nad1 genes. Results: The phylogeny inferred by the Maximum Likelihood algorithm indicated that G1 genotype (n: 19), G3 genotype (n: 14) and G6 genotype (n: 13) assigned into their specific clades. The diversity indices showed a moderate (nad1: Hd: 0.485) to high hap- lotype diversity (cox1: Hd: 0.867) of E. granulosus s.s. (G1/G3) and low nucleotide diver- sity. The negative value of Tajima’s D and Fu’s Fs test displayed deviation from neutrali- ty indicating a recent population expansion. A parsimonious network of the haplotypes of cox1 displayed star-like features in the overall population containing IR9/PAK1/G1, IR2/PAK2/G3 and IR18/G6 as the most common haplotypes. A pairwise fixation index (Fst) indicated that E. granulosus s.s. populations are genetically moderate differen- tiated between southeast of Iran and Pakistan. The extension of haplotypes PAK18/G1 (sheep) and PAK26/G1 (cattle) toward Iranian haplogroup revealed that there is dawn of Echinococcus flow due to a transfer of alleles between mentioned populations through transport of livestock or their domestication. Conclusion: The current findings strengthen our knowledge concerning the evolution- ary paradigms of E. granulosus in southeastern borders of Iran and is effective in control- ling of hydatidosis. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/3366 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/3366/1352