Evaluation of particle agglutination assay for the rapid diagnosis of Japanese encephalitis infection

INTRODUCTION: Japanese encephalitis (JE) is a disease of rural agricultural areas in the Terai regions of Nepal. The aim of the study was to compare particle agglutination assay (PA) with IgM capture ELISA. MATERIALS AND METHODS: The descriptive crosssectional study was conducted from August 2006 to September 2008. A total of 552 serum samples were collected from patients clinically diagnosed as acute encephalitis syndrome (AES) or viral fever in Tribhuvan University Teaching Hospital (TUTH) in Kathmandu, Lumbini Zonal Hospital (LZH) in Rupandehi and Bheri Zonal Hospital (BZH) in Banke districts. The samples were tested for Japanese encephalitis virus (JEV) specific IgM by two serological methods, IgM capture ELISA and PA. RESULTS: Among 552 samples, 258 samples were positive by PA and 205 were positive by IgM capture ELISA. The overall seroprevalence was 46.7% and 37.1% by the PA and IgM ELISA respectively. Two hundred fifty eight samples (47.7%) were positive for anti-JE IgM by PA assay and 200 samples (77.5%) of the 258 PA IgM positive samples were also IgM positive for anti-JE IgM by IgM-capture ELISA. Thus, PA assay had a sensitivity of 97.5% and specificity of 83.3% in comparison with IgM-capture ELISA. A positive predictive value of 0.77 and negative predictive value of 0.98 was observed with PA in comparison with IgM-capture ELISA. CONCULSIONS: The result from PA was highly compatible with IgM capture ELISA. Both sensitivity and specificity of PA was acceptable in comparison with IgM-capture ELISA. DOI: http://dx.doi.org/10.3126/ijim.v1i1.6770 Int J Infect Microbiol 2012;1(1):20-23