Department of Parasitology, Asahikawa Medical University, Asahikawa, Japan.
Department of Parasitology, Asahikawa Medical University, Asahikawa, Japan; Department of Medical Biology and Histology, School of Biomedicine, Health Sciences University of Mongolia, Ulaanbaatar, Mongolia.
PLoS Negl Trop Dis. 2014 Jun 19;8(6):e2937. doi: 10.1371/journal.pntd.0002937. eCollection 2014 Jun.
Cystic echinococcosis (CE) is a globally distributed cestode zoonosis that causes hepatic cysts. Although Echinococcus granulosus sensu stricto (s.s.) is the major causative agent of CE worldwide, recent molecular epidemiological studies have revealed that E. canadensis is common in countries where camels are present. One such country is Mongolia.
METHODOLOGY/PRINCIPAL FINDINGS: Forty-three human hepatic CE cases that were confirmed histopathologically at the National Center of Pathology (NCP) in Ulaanbaatar (UB) were identified by analysis of mitochondrial cox 1 gene as being caused by either E. canadensis (n=31, 72.1%) or E. granulosus s.s. (n=12, 27.9%). The majority of the E. canadensis cases were strain G6/7 (29/31, 93.5%). Twenty three haplotypes were identified. Sixteen of 39 CE cases with data on age, sex and province of residence were citizens of UB (41.0%), with 13 of the 16 cases from UB caused by E. canadensis (G6/7) (81.3%). Among these 13 cases, nine were children (69.2%). All pediatric cases (n = 18) were due to E. canadensis with 17 of the 18 cases (94.4%) due to strain G6/7. Serum samples were available for 31 of the 43 CE cases, with 22 (71.0%) samples positive by ELISA to recombinant Antigen B8/1 (rAgB). Nine of 10 CE cases caused by E. granulosus s.s. (90.0%) and 13 of 20 CE cases by E. canadensis (G6/7) (65.0%) were seropositive. The one CE case caused by E. canadensis (G10) was seronegative. CE cases caused by E. granulosus s.s. showed higher absorbance values (median value 1.131) than those caused by E. canadensis (G6/7) (median value 0.106) (p = 0.0137).
CONCLUSION/SIGNIFICANCE: The main species/strains in the study population were E. canadenis and E. granulossus s.s. with E. canadensis the predominant species identified in children. The reason why E. canadensis appears to be so common in children is unknown.
包虫病（CE）是一种分布广泛的绦虫动物源性疾病，可导致肝囊肿。尽管细粒棘球绦虫（Echinococcus granulosus sensu stricto，s.s.）是全球范围内引起 CE 的主要病原体，但最近的分子流行病学研究表明，在有骆驼存在的国家，加拿大棘球绦虫很常见。蒙古就是这样一个国家。
方法/主要发现：通过对线粒体 cox1 基因的分析，在乌兰巴托国家病理学中心（UB）确认了 43 例经组织病理学证实的人类肝包虫病病例，这些病例分别由加拿大棘球绦虫（n=31，72.1%）或细粒棘球绦虫 s.s.（n=12，27.9%）引起。加拿大棘球绦虫病例中，G6/7 株（29/31，93.5%）占大多数。共发现 23 种单倍型。39 例有年龄、性别和居住地数据的包虫病病例中，23 例（UB）为 UB 市民（41.0%），其中 16 例（UB）由加拿大棘球绦虫（G6/7）引起（81.3%）。这 16 例中有 9 例为儿童（69.2%）。所有儿科病例（n=18）均由加拿大棘球绦虫引起，其中 18 例（94.4%）为 G6/7 株。血清样本可用于 43 例包虫病病例中的 31 例，其中 22 例（71.0%）的重组抗原 B8/1（rAgB）ELISA 检测为阳性。10 例由细粒棘球绦虫 s.s.引起的包虫病病例中有 9 例（90.0%）和 20 例由加拿大棘球绦虫（G6/7）引起的包虫病病例中有 13 例（65.0%）为血清阳性。由加拿大棘球绦虫（G10）引起的 1 例包虫病病例为血清阴性。由细粒棘球绦虫 s.s.引起的包虫病病例的吸光度值（中位数 1.131）高于由加拿大棘球绦虫（G6/7）引起的包虫病病例（中位数 0.106）（p=0.0137）。
结论/意义：研究人群中的主要物种/株是加拿大棘球绦虫和细粒棘球绦虫 s.s.，儿童中以加拿大棘球绦虫为主。加拿大棘球绦虫在儿童中如此常见的原因尚不清楚。
