Phitsanulok Province with district boundaries (study area). Inset box shows location of Phitsanulok Province (red) in Thailand. Red stars indicate the 92 villages which were sampled three times (i.e. March, May and July) during 2009. Dots indicate all the villages in Phitsanulok Province. Total area of Phitsanulok is approximately 10,816 km2.
Sarfraz et al. BMC Public Health 2012 12:853 doi:10.1186/1471-2458-12-853