O. viverrini positivity in the whole study group (ages 35-68) was 9.3%, comparable to recently published national prevalence in adults estimates of 9.4% in 2000 and 8.7% in 2009, as well as the 14.2% for Khon Kaen province in 2009 (Jongsuksuntigul et al., 2003; Sithithaworn et al., 2012).