Use of IgM-capture ELISA for confirmation of Japanese encephalitis infections in the Philippines.

In 2001, the Research and Biotechnology Division (RBD) of St Luke's Medical Center, in collaboration with the Institute of Tropical Medicine of Nagasaki University in Japan, initiated a long-term study of Japanese encephalitis in the Philippines. Laboratory confirmation of acute cases of Japanese. encephalitis was done by IgM-capture ELISA, which detects anti-JEV immunoglobulin M in cerebrospinal fluid (CSF) samples. In the period 2002-2004, a total of 614 CSF samples were submitted to RBD, and of these, 11.7% were positive for anti-JEV IgM: 17 in 2002, 18 in 2003, 32 in 2004, and 5 in 2005. Positive cases came from patients aged 2-77 years. In the 72 positive cases where gender was identified, 44 were male and 28 female. Possible co-infections with dengue virus were also detected by separate testing for anti-dengue IgM by ELISA in 17 CSF samples positive for JE.