Kim Yeong Hoon, Lee Ji Hoo, Ahn Seong Kyu, Kim Tong-Soo, Hong Sung-Jong, Chong Chom-Kyu, Ahn Hye-Jin, Nam Ho-Woo
Department of Ophthalmology, College of Medicine, Catholic University of Korea, Seoul 06591, Korea.
Genbody Inc., Cheonan 31116, Korea.
Korean J Parasitol. 2017 Jun;55(3):247-254. doi: 10.3347/kjp.2017.55.3.247. Epub 2017 Jun 30.
ELISA has been used for the diagnosis of toxoplasmosis, but it is being gradually replaced by a rapid diagnostic test (RDT). We compared and analyzed ELISA and RDT results using the sera collected during 4 consecutive years from residents of Gyodong-do (Island), Incheon-city, Korea. Sera from 921, 993, 940, and 838 adult residents were collected on a yearly basis (2010-2013). ELISA was performed by using a crude extract of RH strain antigen and IgG/IgM RDT mounted with recombinant fragment of major surface antigen (SAG1), GST-linker-SAG1A, were applied to the sera. Comparison between groups was analyzed by the Student's t-test. The positive seroprevalence surged from 14.7% (135/921, 2010), 23.1% (231/993, 2011), 23.6% (222/940, 2012), and 32.1% (269/838, 2013) by ELISA. In contrast, RDT showed a more moderate increasing trend from 21.7% (200/921, 2010), 25.5% (253/993, 2011), 28.9% (272/940, 2012) and 33.1% (277/838, 2013). Discrepancies between ELISA and RDT were noted near the cut-off value. At the OD 0.15-0.24 range, RDT could detect 16.1% (169/1051) more positives, which suggests an early or acute toxoplasmosis, but at the OD 0.25-0.34 range, ELISA could detect 35.9% (92/256) more positives of possible chronic infections. Over the OD > 0.35 ELISA and RDT agreed in the majority of the cases. This surge in seroprevalence may be caused by the organic agriculture in addition to eating behavior or increase in pets among Koreans. These facts may be applied on a full-scale national survey using RDT to supplement ELISA to define the characteristics of the infection.
酶联免疫吸附测定（ELISA）已用于弓形虫病的诊断，但它正逐渐被快速诊断检测（RDT）所取代。我们使用从韩国仁川市鹫岛居民连续4年收集的血清，对ELISA和RDT的结果进行了比较和分析。每年（2010 - 2013年）收集921、993、940和838名成年居民的血清。ELISA采用RH株抗原粗提物进行检测，而RDT则使用主要表面抗原（SAG1）的重组片段GST-连接子-SAG1A检测血清中的IgG/IgM。组间比较采用学生t检验进行分析。ELISA检测的阳性血清流行率从2010年的14.7%（135/921）、2011年的23.1%（231/993）、2012年的23.6%（222/940）和2013年的32.1%（269/838）呈上升趋势。相比之下，RDT显示出更为平缓的上升趋势，从2010年的21.7%（200/921）、2011年的25.5%（253/993）、2012年的28.9%（272/940）到2013年的33.1%（277/838）。在临界值附近注意到ELISA和RDT之间存在差异。在OD值为0.15 - 0.24范围内，RDT能多检测出16.1%（169/1051）的阳性结果，这表明可能是早期或急性弓形虫病，但在OD值为0.25 - 0.34范围内，ELISA能多检测出35.9%（92/256）可能为慢性感染的阳性结果。在OD值>0.35时，ELISA和RDT在大多数情况下结果一致。血清流行率的这种上升可能除了韩国人的饮食习惯或宠物数量增加外，还与有机农业有关。这些事实可应用于使用RDT进行的全面全国性调查，以补充ELISA来确定感染特征。
