with the distribution of OV infection going from densely clustered medium to heavy infections to widely dispersed light OV infections, but with the rates of hepatobiliary pathology, especially CCA, remaining the highest in the world. Mass Drug Administration using praziquantel for opisthorchiasis in Thailand commenced in 1984, when the prevalence of OV was on average 63%, with MDA continuing until 2001 which brought the average prevalence of OV down to 9.3% [1]