Genetic characterization ofEchinococcusisolates from various intermediate hosts in the Qinghai-Tibetan Plateau Area, China

Abstract

This study examined Echinococcus spp. genotypes and genetic variants isolated from humans as well as domestic and wild animals from the Qinghai-Tibetan Plateau Area using the cox1 gene. All samples except the pika isolates were identified as the Echinococcus granulosus sensu stricto. Sixteen different haplotypes with considerable intraspecific variation were detected and characterized in mitochondrial cox1 sequences. The parsimonious network of cox1 haplotypes showed star-like features, and the neutrality indexes computed via Tajima's D and Fu's Fs tests showed high negative values in E. granulosus s. s., indicating deviations from neutrality; the Fst values were low among the populations, implying that the populations were not genetically differentiated. The pika isolates were identified as E. multilocularis and E. shiquicus. Only one haplotype was recognized in the pika isolates. E. granulosus s. s. was the predominant species found in animals and humans, followed by E. multilocularis and E. shiquicus, with high genetic diversity circulating among the animals and humans in this area. Further studies are needed to cover many sample collection sites and larger numbers of pathogen isolates, which may reveal abundant strains and/or other haplotypes in the hydatid cysts infecting human and animal populations of the QTPA, China.

Meta-Analysis of the Prevalence of Echinococcus in Sheep in China From 1983 to 2020

“…Among the included articles, most of the epidemiological investigations were concentrated in the northwestern region (91%; Table 2). The northwestern region was the main breeding area for sheep in China and was also a high-epidemic area for echinococcosis ( Han et al., 2019 ), among which Qinghai province has the highest prevalence rate ( Figure 3 ). From the perspective of geographic environment, the altitude subgroup analysis showed a relatively high prevalence of Echinococcus among sheep in high altitude areas, such as Qinghai province ( P < 0.05; Table S6 ).…”

Echinococcus shiquicus in Qinghai–Tibet plateau: population structure and confirmation of additional endemic areas

“…It was also, detected around Qinghai Lake in Ganzihe town of Haiyan County and Gonggongma village of Gangcha County towards the northeastern edge of the plateau. Until now, the diversity and population structure of E. shiquicus has been largely investigated by partial mitochondrial gene sequences of cox1 and/or nad1 (Ma et al, 2012(Ma et al, , 2015Wang et al, 2018;Han et al, 2019), and recently by mtDNA sequences of up to 2505 bp (Fan et al, 2016;Zhu et al, 2020). Moreover, studies have shown that by analysing longer DNA sequences or certain genes with higher resolution power, a better understanding of the intraspecies variation and phylogenetic resolution of Echinococcus species is realised (Laurimäe et al, 2018(Laurimäe et al, , 2019Ohiolei et al, 2020).…”

“…Since the discovery of E. shiquicus, progress has been made in understanding the genetic diversity and population structure, howbeit by short mitochondrial gene sequences of the cytochrome c oxidase subunit 1 (cox1) and the NADH dehydrogenase subunit 1 (nad1) (Ma et al, 2012(Ma et al, , 2015Wang et al, 2018;Han et al, 2019), with only a few studies employing longer mtDNA sequences (2505 bp) (Fan et al, 2016;Zhu et al, 2020). Meanwhile, a better insight into the population structure will require an extensive investigation across the plateau as conflicting population demographics/indices have so far been observed, which is either a consequence of short DNA sequences or sample size limitations.…”

Establishment of a secondary infection laboratory model of Echinococcus shiquicus metacestode using BALB/c mice and Mongolian jirds (Meriones unguiculatus)

“…Meanwhile, there are speculations that the speciation between both of them is a passive host transformation as a result of the evolution of their intermediate hosts, which eventually led to their ecological isolation and gave rise to 2 distinct species (Wang et al ., 2020 ; Wu et al ., 2021 ). Rodents, for instance, plateau pika ( Ochotona curzoniae ), the plateau vole ( Neodon fuscus ) and carnivorous' mammals, predominantly Tibetan foxes ( Vulpes ferrilata ) serve as intermediate and definitive hosts, respectively (Jiang et al ., 2012 ; Li et al ., 2018 , 2019 ; Han et al ., 2019 ). At present, E. shiquicus infection has been found in a variety of wild animals such as plateau pika, plateau vole, lacustrine vole ( Microtus limnophilus ), Blyth's mountain vole ( Phaiomys leucurus ) and Tibetan foxes in Sichuan Province, Qinghai Province, Tibet Autonomous Region, Gansu Province and other provinces/autonomous regions in the Qinghai-Tibet Plateau area, China (Boufana et al ., 2013 ; Fan et al ., 2016 ; Wang et al ., 2018 ; Weng et al ., 2020 ; Zhu et al ., 2020 ).…”