an increasing trendP <0.001
An increasing trend with IgG was observed along with the age groups [6-15 yr (36%), 16-25 yr (45%) and >25 yr (69%), P <0.001], and it was maximum in village Hamimpur (68%) followed by Belakata (65%), Kazipur (51%), Rajhi (39%) and Vikas Nagar (34%), ( P <0.001).