Update on the genetic diversity and population structure of Echinococcus granulosus in Gansu Province, Tibet Autonomous Region, and Xinjiang Uygur Autonomous Region, Western China, inferred from mitochondrial cox1, nad1, and nad5 sequences.

The identification of additional Echinococcus granulosus sensu lato (s.l.) complex species/genotypes in recent years raises the possibility that there might be more variation among this species in China than is currently understood. The aim of this study was to explore intra- and inter-species variation and population structure of Echinococcus species isolated from sheep in three areas of Western China. Of the isolates, 317, 322, and 326 were successfully amplified and sequenced for cox1, nad1, and nad5 genes, respectively. BLAST analysis revealed that the majority of the isolates were E. granulosus s.s., and using the cox1, nad1, and nad5 genes, respectively, 17, 14, and 11 isolates corresponded to Elodea canadensis (genotype G6/G7). In the three study areas, G1 genotypes were the most prevalent. There were 233 mutation sites along with 129 parsimony informative sites. A transition/transversion ratio of 7.5, 8, and 3.25, respectively, for cox1, nad1, and nad5 genes was obtained. Every mitochondrial gene had intraspecific variations, which were represented in a star-like network with a major haplotype with observable mutations from other distant and minor haplotypes. The Tajima's D value was significantly negative in all populations, indicating a substantial divergence from neutrality and supporting the demographic expansion of E. granulosus s.s. in the study areas. The phylogeny inferred by the maximum likelihood (ML) method using nucleotide sequences of cox1-nad1-nad5 further confirmed their identity. The nodes assigned to the G1, G3, and G6 clades as well as the reference sequences utilized had maximal posterior probability values (1.00). In conclusion, our study confirms the existence of a significant major haplotype of E. granulosus s.s. where G1 is the predominant genotype causing of CE in both livestock and humans in China.

Seroprevalence and risk factors of bovine viral diarrhoea virus (BVDV) infection in yaks (Bos grunniens) in northwest China.

Bovine viral diarrhoea virus (BVDV), a member of the Pestivirus genus, is an important pathogen of cattle worldwide, causing reproductive disorders in adult cattle and mucosal disease in calves. However, limited information about BVDV infection in yaks (Bos grunniens) in China is available, especially in white yaks which is a unique yak breed that only lives in Tianzhu Tibetan Autonomous County (TTAC), Gansu Province, northwest China. Therefore, we conducted a cross-sectional study to estimate the seroprevalence and risk factors associated with BVDV infection in 1584 yaks in Gansu province, northwest China, between April 2013 and March 2014 using an indirect ELISA test. The overall seroprevalence of BVDV in yaks was 37.56 % (595/1584), with 45.08 % (275/610) in black yaks and 32.85 % (320/974) in white yaks. Moreover, positive yaks were found in all four regions, varied from 33.22 to 40.31 %. Male yaks had a similar seroprevalence (37.84 %) with that of the female yaks (37.11 %). Season, species and geographical origins of yaks were considered as risk factors analyzed by logistic regression model. To our knowledge, this is the first report of seroprevalence and risk factors associated with BVDV infection in white yaks in China.