山丘型血吸虫病流行区人群血吸虫抗体消长监测

Surveillance of schistosome antibodies in population in mountainous schistosomiasis endemic regions in China

目的了解山丘型血吸虫病轻疫区人群血吸虫抗体水平的变化规律。方法选择四川省丹棱县桂香村为试区,每年秋季采用间接血凝试验(IHA)检查村民血吸虫感染情况,阳性者再以Kato Katz法检查。选择2006-2011年连续参加检查的人群,分析人群血吸虫抗体阳性率、抗体滴度(GMRT)、每克粪便虫卵数(EPG)变化。结果2006-2011年桂香村共有353人连续参加血吸虫病检查,人群血吸虫抗体阳性率从20.73%下降到13.67%,人群GMRT从1.63下降到1.06。抗体阳性者转归以阴转为主,抗体滴度逐年降低;抗体阴性者多维持阴性。血吸虫病确诊患者化疗后,抗体阳性率从100%下降到20%,GMRT从34.29下降到1.58。GMRT与EPG呈高度正相关(r=0.94,P<0.05)。结论山丘型血吸虫病轻疫区人群血吸虫抗体阳性率维持在较高水平;应规范血吸虫病免疫诊断方法,开发适用于不同流行程度疫区的诊断试剂。

Objective To understand the dynamics of schistosome antibodies in population in mountainous schistosomiasis low endemic regions, China, so as to provide the evaluation reference for immunodiagnosis. Methods The people who consecu- tively received the indirect heamagglutination assay （IHA） for schistosomiasis and Kato-Katz technique were enrolled in this study in Guixiang Village, Danling County, Sichuan Province from 2006 to 2011. The positive rates for schistosome antibodies, anti- body titers and eggs per gram （EPG） were analyzed. Results A total of 353 people were investigated in this study from 2006 to 2011. The positive rates for schistosome antibodies decreased from 20.73% to 13.67%, and the geometric mean reciprocal titer （GMRT） decreased from 1.63 to 1.06. The antibodies tended to be negative in most antibody-positive people and the GMRT de- creased gradually. The antibodies remained negative in most antibody-negative people. After chemotherapy in parasitology con- firmed patients, the positive rate for schistosome antibodies decreased from 100% to 20%, and the GMRT decreased from 34.29 to 1.58. There was a highly positive correlation between GMRT and EPG （r = 0.94, P 〈 0.05）. Conclusion The positive rate for schistosome antibodies in population in mountainous schistosomiasis low endemic regions is relatively high （13.67%）. The stan- dardization of immunodiagnostic methods is necessary and the suitable diagnostic reagents should be developed in this region.