Comparison of ELISA and RDT in the diagnosis of human toxoplasmosis

초록

ELISA has been used popularly in the diagnosis of toxoplasmosis, but for the time-consuming procedure and the need of skilled technician, it is now replaced gradually by a rapid diagnostic test (RDT), the universal trend of diagnosis. Here, we compared two methods in the survey of residents in an island located in the Yellow Sea nearby Incheon city, Korea. Routine IgG-ELISA with Toxoplasma gondii (RH strain) crude antigen and IgG/IgM RDT mounted with recombinant fragment of major surface antigen (SAG1), GST-linker-SAG1A, were applied to the sera from the residents for 4 years from 2010 to 2013 about 900 persons per year. In 2010, ELISA detected 135 positives among 921 (14.7%) and RDT detected more sensitively 202 positives (21.9%). But, RDT detected 87.4% (118 sera) of ELISA positives except for those sera of controversial OD just above the cut-off value, instead detected more positives in ELISA-negatives of 10.7% (84 sera). This pattern was maintained in 2011, 2012 and 2013 with the increasing seroprevalence of 23.3%, 23.6% and 32.1% by ELISA and 26.8%, 28.9% and 33.3% by RDT, respectively. IgM was detected in 3 sera in 2010, 1 in 2011, 7 in 2012 and 13 in 2013. This surgical increase in seroprevalence is suggested to be due to the organic agriculture in addition to eating behavior or pet loving of Korean.