Species identification of human echinococcosis using histopathology and genotyping in northwestern China

Abstract

SummaryHuman cystic echinococcosis, caused by infection with the larval stage of Echinococcus granulosus, and alveolar echinococcosis, caused by the larval form of E. multilocularis, are known to be important public health problems in western China. Echinococcus shiquicus is a new species of Echinococcus recently described in wildlife hosts from the eastern Tibetan plateau and its infectivity and/or pathogenicity in humans remain unknown. In the current study, parasite tissues from various organs were collected post-operatively from 68 echinococcosis patients from Sichuan and Qinghai provinces in eastern China. The tissues were examined by histopathology and genotyped using DNA sequencing and PCR-RFLP. Histopathologically, 38 human isolates were confirmed as E. granulosus and 30 as E. multilocularis. Mitochondrial cob gene sequencing and PCR-RFLP with rrnL as the target gene confirmed 33 of 53 of the isolates to have the G1 genotype of sheep/dog strain of E. granulosus as the only source of infection, while the remaining 20 isolates were identified as E. multilocularis. No infections were found to be caused by E. shiquicus. Additionally, 5 of 20 alveolar echinococcosis patients were confirmed to have intracranial metastases from primary hepatic alveolar echinococcosis lesions. All these cases originated from four provinces or autonomous regions but most were distributed in Sichuan and Qinghai provinces, where high prevalence rates of human alveolar echinococcosis and cystic echinococcosis were previously documented. * Corresponding author. Present address: 6 Zhong Xue Lu, Chengdu 610041, Sichuan Province, People's Republic of China. Tel.: +86 28 85589532; fax: +86 28 85589563. E-mail address: litiaoying@sina.com (T. Li). Authors' contributions: TL, AI, PSC and JQ designed the study protocol and drafted the manuscript; TL, PSC, AI and PG performed the analysis and interpretation of data; TL, MN, NX and XW conducted genetic analysis of all specimens; RZ did surgery; KN and MN did histopathology for morphological and molecular analysis; TL, CX and JQ collected tissue samples in the endemic areas. All authors read and approved the final manuscript. TL is guarantor of the paper.

Genetic polymorphisms of Echinococcus tapeworms in China as determined by mitochondrial and nuclear DNA sequences

“…In China, E. granulosus s. s. and E. multilocularis are widespread in western, northern and central parts of the country (Wang et al, 2008), and hyperendemic foci exist within pastoral areas of the eastern Tibetan Plateau (Schantz et al, 2003; Li et al, 2008) and the Xinjiang Uyghur Autonomous Region (Wang et al, 2001). Both endemic regions are geographically separated by the Kunlum mountains and the Taklamakan Desert.…”

Molecular identification of Echinococcus species from eastern and southern Qinghai, China, based on the mitochondrial cox1 gene

“…Not enough attention, however, has been paid to the study of taxonomic identification of Echinococcus species in such a vast region. Recently, the first molecular studies have been undertaken on Echinococcus transmitted in this region, but sampling has been geographically relatively restricted Nakao et al 2010) or only concerned a single parasite species (Xiao et al 2005(Xiao et al , 2006bMa et al 2008) or host (Li et al 2008) species.…”

Molecular Diagnosis of Polycystic Echinococcosis Due to Echinococcus vogeli in a Paraguayan Immigrant in Argentina

“…In our case, the FFPE liver tissue samples were the only available specimen for further molecular study. Amplification failed using previously published pan-Echinococcus PCR targeting mtDNA genes (cox1 and cob; data not shown) (1,2,4,15) or E. vogeli-specific PCR (14). As these techniques require amplification of long DNA fragments (Ͼ400 bp), we designed new primers, which target DNA polymorphic sequences (Ͻ300 bp), i.e., cox1 and cob.…”