血吸虫病低流行状态下抗体检测的现场应用价值

Field Application of Antibody Detection in a Low Transmission Area of Schistosoma japonicum

目的评价间接红细胞凝集试验（IHA）和ELISA在血吸虫病低流行状态下的现场应用价值。方法于2008年和2010年同时采用改良加藤厚涂片法（Kato—Katz法）、IHA和ELISA平行检测鄱阳湖区血吸虫病流行区新华村728人和799人．并以三送二十七检Kat0-Katz法结果为金标准对免疫诊断结果进行评估。结果2008年和2010年人群Kato。Katz法、IHA和ELISA检出阳性率分别为10.3％（75／728）和3．8％（30／799）、40．0％（291／728）和31．5％（252／799）、40．1％（292／728）和40．1％（320／799），其中Kato—Katz法（X2=26．92，P〈0．05）和IHA阳性率（x2=11．82，P〈0．05）年间的差异均有统计学意义。IHA、ELISA的诊断结果与粪检结果的一致性较差，Kappa值均低于0．2（均P〈0．01）。IHA或ELISA筛查阳性者再以Kato—Katz’S法确诊。结果表明粪检阳性检出率与送粪次数和检查片数呈正相关（rIHA2008=0．922，rIHA2008=0．908，qnA2010=0．749，rELISA201种．798；均P〈0．05）。IHA和ELISA阴性的粪检阳性者主要为低感染度患者，每克粪虫卵数（EPG）≤40时，IHA抗体阳性率为66．1％（39／59）-87．0％（20／23）．EUSA抗体阳性率为62．7％（37／59）～100％（23／23）；EPG〉40时，ELISA均为阳性，但IHA仍有呈阴性者。结论为提高血吸虫病低流行状态下IHA和ELISA的诊断能力，降低假阳性和假阴性．建议人群化疗对象的确定采用血检过筛后Kato—Kat：粪检．由常规的“一送三检”改为“一送九检”。

Objective To evaluate the field application of IHA and ELISA for schistosomiasis japonica detection at low transmission status. Methods 728 and 799 persons were examined by Kato-Katz＇s method, IHA and ELISA for schistosomiasis in an endemic village in the year of 2008 and 2010, respectively. The results of IHA and ELISA was evaluated in comparison to that of Kato-Katz （27 slides with 3 stool specimens） used as gold standard. Results The positive rate of Kato-Katz＇s method, IHA and ELISA were 10.3% （75/728）, 40.0% （291/728） and 40.1% （292/728） in 2008, and 3.8% （30/799）, 31.5% （252/799） and 40.1% （320/799） in 2010 respectively, in which significant difference was observed for the result between Kato-katz＇s method （X2=26.92,P〈O.05） and IHA（x2=ll.82,P〈0.05）. The consistence between the result of antibody detection and that of Kato-Katz＇s method was poor, lower than 0.2 （P〈0.01）. If routine screening diagnosis mode was adopted, namely, population screened with IHA or ELISA first and confirmed with KatoKatz＇s method, correlation analysis showed that the positive rate of Kato-Katz＇s method increased with the number of stool specimens and slides （rIHA2008=0.922, rIHA2008=0.908, rIHA2008=0.749,rIHA2008=0.798; P〈0.05） . Those with egg positive but missed by IHA or ELISA mainly were cases with low infection intensity. When EPG〈40, the rate of detection ranged from 66.1% （39/59） to 87.0% （20/23） with IHA, and 62.7% （37/59） to 100% （23/23） with ELISA. When EPG〉 40, however, all cases could be detected with ELISA, but some missed with IHA. Conclusion In low transmission areas, the determination of target population for chemotherapy should be based on the examination of nine slides perstool specimen by Kato-Katz＇s method after serological screening.