Figure 2

Relationship between the prevalence (A) and output (B) of Opisthorchis viverrini cercariae and shell-size of Bithynia siamensis goniomphalos . Mean values (±95% CI) are shown. Black bars represent size-classes based on shell length (small = <8.0 mm, medium-sized = 8.1–10.0 mm, large = >10.0 mm); white bars represent size-classes based on shell width (small = <5.0 mm, medium-sized =5.1–6.0 mm, large = >6.0). *P <0.05, **P <0.01, ***P <0.001. The absence of a bar reflects the lack of infected snails within the corresponding size-class collected.