Chenyang Xia

Echinococcosis, also known as hydatid disease, is caused by the metacestode stage of the species cluster Echinococcus granulosus sensu lato (E. granulosus s.l.). It is almost widespread worldwide, especially in countries and regions dominated by animal husbandry. It is a major parasitic disease that seriously endangers human health, public health safety, environmental safety, and the development of animal husbandry production in western China. In this study, the mitochondrial cox1 gene was used to analyze the genetic diversity and haplotype of bovine and sheep echinococcal cysts isolated in Tibet. Echinococcus granulosus sensu stricto (E. granulosus s.s., G1, G3) was still the dominant species in the infected samples of yak and sheep in some parts of Tibet. Through haplotype analysis, Hap_1 was deemed the dominant haplotype, 14 of the 20 haplotypes were similar to the reference sequence previously published in Genbank, and the rest of the 6 haplotypes were found for the first time. Through Tajima's D value, neutral test Fu's Fs analysis, and haplotype network map, it can be concluded that Echinococcus population expansion has occurred in Xigaze, Tibet. This study provides basic data for understanding the genetic characteristics, epidemiology, and control of echinococcosis in this area.

Background: Objective The study on the infection of hydatid disease in yaks in China provides the general epidemiological information of hydatid disease infection in yaks, which is of great value for the formulation of prevention and control strategies for hydatid disease. Method The database of yak hydatid disease infection rate was established by WPS Excel (version 11.1.0.11045-release). The provincial boundaries are vectorized by ArcGIS10.8 software, and the national and provincial boundaries and center vector maps are obtained. Taking the total number of yaks in different regions of China and the infection rate of hydatid disease of yaks in recent 40 years as attribute data, the data were matched with the basic map, and the spatial distribution map was drawn. Finally, spatial autocorrelation analysis, spatial clustering analysis, clustering and outlier analysis were used to analyze the spatial distribution of hydatid disease infection rate in county yaks in China. Results: Except for Yunnan Province, yaks were infected with hydatid disease in the other five provinces and autonomous regions. The infection rate of hydatid disease in yaks in the five provinces has shown a downward trend in the past 40 years. The species of Echinococcus granulosus and Echinococcus multilocularis infected by yaks in five provinces were Echinococcus granulosus and Echinococcus multilocularis. There was no Echinococcus multilocularis infection in yaks in Xinjiang. The results of spatial distribution of yak hydatid disease infection in counties of China showed that there were yak hydatid disease infection in 65 counties of five provinces in China. Most of the counties with high infection rate are concentrated at the junction of eastern, western and southeastern Qinghai province, and the average infection rate of hydatid disease in yak is more than 60%. However, the average infection rate of hydatid disease in yaks in western Xinjiang Autonomous region, Tianzhu County in Gansu Province and northeastern Qinghai Province is less than 10%. Conclusions: This is the first time based on ArcGIS to study the infection of hydatid disease in yaks in recent 40 years in China. The advantage is obvious and the spatial distribution is clear immediately.

Background: Cystic echinococcosis (CE) in humans and livestock is caused byEchinococcus granulosus(sensu lato). In China where CE is endemic, a number of studies have shown thatEchinococcus granulosus(sensu stricto) is majorly responsible for CE. However,E. canadensis(G6) which is the second leading cause of CE is now being detected in most parts of the country. In this study, the species diversity and genetic variation ofEchinococcus granulosus(s.l.) in four counties in Tibet Autonomous Region of China were investigated.Methods: Infection withEchinococcus granulosus(s.s.) in yaks and sheep was identified using NADH dehydrogenase subunit 1 and 5 (nad1 andnad5) mitochondrial genes while the genotype G6 ofE. canadensisinitially diagnosed with NADH dehydrogenase subunit 1 (nad1) was further confirmed by analysis of the complete mitochondrial genome and a phylogenetic network constructed based on thenad2 andnad5 genes.Results: Out of 85 hydatid cyst samples collected from slaughtered sheep (n = 54) and yaks (n = 31), 83 were identified asE. granulosus(s.s.) G1 (n = 77), G3 (n = 6) and 2 were identified asE. canadensisG6. Analysis of thenad1/nad5 genes revealed 16/17 mutations with 9/14 parsimony informative sites resulting in 15/14 haplotypes, respectively. Haplotype diversity (Hd) and nucleotide diversity (π) ofE. granulosus(s.s.) population were 0.650 and 0.00127 fornad1 and 0.782 and 0.00306 fornad5, respectively, with an overall negative Tajima’sDand Fu’s Fs. A low F_STindicated no genetic difference between isolates from sheep and yaks.Conclusion: Pockets of infection withE. canadensis(G6, G7, G8 and G10) have been previously reported in sheep, goats, yaks and/or humans in different parts of China. While the G6 genotype has been previously reported in sheep in the Tibet Autonomous Region, the detection in a yak in the present study represents the first to the best of our knowledge. Therefore, we recommend future surveys and control efforts to comprehensively investigate other potential intermediate hosts for the prevalence and genetic diversity of theE. canadensisgroup (G6, G7, G8 and G10) across the country and their inclusion into the existing CE control programme.