Serological prevalence of echinococcosis and risk factors for infection among children in rural communities of southern Ningxia, China

OBJECTIVE To assess the usefulness of serology as an indicator of Echinococcus transmission for developing preventive measures against echinococcosis in rural communities. METHODS Cross-sectional survey in 2002 among 861 children aged 7 to 18 years in Xiji County, Ningxia, China. Before ultrasound abdominal examination, a questionnaire was used to identify socioeconomic, sanitary and hygiene risk factors for echinococcal infection; filter paper blood samples were collected from each child for specific antibody detection using EmP (Echinococcus multilocularis) and EgB (Echinococcus granulosus) antigens. RESULTS Transmission of both E. multilocularis and E. granulosus occur in this area. Serological prevalence was far higher than disease prevalence in this age range. We found no gender-related differences of seroprevalence among the children, suggesting an equal chance of exposure to echinococcal egg-contaminated environments. The seroprevalence distribution was associated with changes in the ecology of wild hosts for E. multilocularis contamination, and with changes in socio-geographic features of the communities for E. granulosus contamination. CONCLUSIONS Serological data obtained for children in mass surveys of echinococcosis appear to be a comprehensive and useful tool to monitor changes of transmission dynamics in humans and provide 'warning signals' to decision makers for the instigation of specific control measures against the disease.