Bingjie Wang ¹ Li Zhao ^2* Wanli Ban ^2* Xu Zhang ^3* Chenxi Quan ^4* Munila •. Teliewuhan ^5* Lixiong He ^6* Zhaoyang Chen ^6* Zhuangzhi Zhang ^2*

• ¹ Veterinary Research Institute, Xinjiang Academy of Animal Sciences(Animal Clinical Medical Research Center, Xinjiang Academy of Animal Sciences), Xinjiang Academy of Animal Science, Ürümqi, China
• ² Veterinary Research Institute, Xinjiang Academy of Animal Sciences(Animal Clinical Medical Research Center, Xinjiang Academy of Animal Sciences), Urumqi, China
• ³ Other, Urumqi, China
• ⁴ Changji Animal Disease Prevention and Control Center, Changji, China
• ⁵ Ili Kazak Autonomous Prefecture Center for Animal Disease Control and Diagnosis, Ili, China
• ⁶ Kekedala Supply and Marketing Cooperative Federation of the Fourth Division of Xinjiang Production and Construction Corps, Kekedala, China

Alveolar echinococcosis (AE) is a life-threatening disease in humans caused by the larval stage of Echinococcus multilocularis. Domestic animal and dogs, foxes and small mammals constitute the circular chain of AE. To evaluate the infection, distribution, and genetic polymorphism of AE in the Ili Prefecture (Nilka, Xinyuan and Zhaosu), 267 small mammals were captured and examined in June and July 2018.Morphological identification revealed that these captured small mammals belonged to three species, Microtus gregalis was the dominant species (183/267). The liver of rodents were isolated for pathological examination, PCR detection and sequencing.Consequenly, it was confirmed that the pathogen of infection was E. multilocularis, and the infection rate was 15.73% (42/267). The infection rates of rodents in Nilka, Xinyuan, and Zhaosu were 25.45% (14/55), 14.06% (18/128), and 11.90% (10/84), respectively. There was no significant difference in infection rates among different regions (χ 2 = 5.119, p > 0.05). The infection rates were 12.12% (8/66) in Microtus ilaeus, 11.11% (2/18) in Ellobius talpinus and 17.49% (32/183) in M. gregalis, with no significant difference detected among different rodent species (χ 2 = 1.364, p > 0.05). Phylogenetic analyses showed that nad1 gene sequences obtained in this study clustered in the same clade with isolates from China. These isolates containing 21 haplotypes (Hap_1-21); Hap_2 was the most common haplotype (9/42). Furthermore, the haplotype diversity (0.925 ± 0.027) and nucleotide diversity (0.01139 ± 0.00119) were higher in Ili Prefecture than in other regions, indicating that population differentiation was high. Tajima's D and Fu's Fs test were negative (p > 0.10), indicating that the population had expanded. The low fixation index (Fst) ranges from 0.00000 to 0.16945, indicating that the degree of genetic differentiation was different among different populations. In summary, Ili Prefecture is a high incidence area of AE, and Microtus spp. may play an important role in the transmission of AE in this area.The results of this study provide basic data for further study of molecular epidemiology, genetic differences and control of E. multilocularis in Ili Prefecture, Xinjiang.