Opisthorchis viverrini infection in rural and urban communities in northeast Thailand

Abstract

The prevalence and intensity of liver-fluke ( Opisthorchis viverrini) infection were investigated among 559 patients who were born in, and had lived all their lives in, either the rural or urban northeastern Thailand. 344 (79·4%) of 433 rural dwellers were infected compared with only 69 (54·8%) of 126 urban dwellers ( P < 0·005). The intensity of infection, and the reported level of consumption of koi-pla, a favourite dish of local inhabitants prepared from uncooked freshwater fish which often contains viable metacercariae, were greater among rural dwellers than their urban counterparts ( P <0·05 to P < 0·005). Infection due to O. viverrini appears to be mainly a rural problem strongly associated with the habit and frequency of eating koi-pla.