ABSTRACT
BACKGROUND: 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 â=â 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 â=â 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.
Subject(s)
Echinococcosis, Hepatic/diagnosis , Echinococcosis, Hepatic/epidemiology , Echinococcus/isolation & purification , Adolescent , Adult , Aged , Animals , Antibodies, Helminth/blood , Child , Child, Preschool , Echinococcus/classification , Echinococcus/genetics , Echinococcus/immunology , Electron Transport Complex IV/genetics , Female , Haplotypes , Humans , Male , Middle Aged , Molecular Epidemiology , Molecular Sequence Data , Mongolia/epidemiology , Risk Factors , Sequence Analysis, DNA , Young AdultABSTRACT
Alveolar echinococcosis cases diagnosed histopathologically in 2002, 2006, 2007, and 2009 in Ulaanbaatar, Mongolia were reconfirmed by evaluating the cytochrome c oxidase subunit I gene of mitochondrial DNA. The most recent three cases using paraffin-embedded and ethanol-fixed specimens revealed that one was of the "Asian" haplotype, whereas two others were of the "Inner Mongolian" type. All patients were born in the western provinces of Mongolia, they never resided outside of Mongolia, and they were given a preliminary diagnosis of malignant hepatic tumor or abscess. The most recent two cases were also confirmed serologically to be active alveolar echinococcosis.
