Effects of 5 rounds of mass drug administration with diethylcarbamazine and albendazole on filaria-specific IgG4 titers in urine: 6-year follow-up study in Sri Lanka

ELISA for filaria-specific IgG4 in urine (urine ELISA) was applied to children in 7 schools in Sri Lanka, before and after 5 rounds of annual mass drug administration (MDA). The pre-treatment IgG4 prevalence in 2002 was 3.20%, which decreased to 0.91% in 2003 after the first MDA (P < 0.001), and finally to 0.36% in 2007 after the 5th MDA. Among 5–10 year-old children, the prevalence decreased from 3.37% in 2002 to 0.51% in 2003 (P = 0.009). A pattern of IgG4 titer distribution according to age and its yearly change could also provide useful information in drug efficacy analysis. In 2008, new samples from eleven 2006/07 urine ELISA-positive students and their family members (total n = 56) were examined by ICT antigen test, microfilaria test, and urine ELISA. No infection was confirmed among them. Urine ELISA will be useful in monitoring elimination/resurgence in a post-MDA low endemic situation.

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► ELISA for filaria-specific IgG4 in urine was applied to school children in Sri Lanka.
► They were examined before and after 5 rounds of MDA.
► The pre-treatment IgG4 prevalence, 3.20%, decreased to 0.36% after the 5th MDA.
► Yearly changes of IgG4 titer provided useful information in MDA efficacy analysis.
► Urine ELISA will be useful in monitoring extinction/resurgence after MDA.