Higher attack rate of fish-borne trematodes (Heterophyidae) in common carp fingerlings (Cyprinus carpio) at lower fish weight

Fish-borne zoonotic trematodes (FZTs) can cause pathology in humans. Fish weight was reported as important risk factor for transmission from snail to fish. However, in fingerlings, the relation between fish weight and infection is unknown. Aim was quantifying the effect of fish weight on infection probability, attack rate, and metacercariae burden of FZTs in common carps (Cyprinus carpio) between 1 and 20 g. Fish were either used as controls (n¿=¿66) or exposed to 250 parapleurolophocercous cercariae (n¿=¿254). Fish weight was analysed as continuous explanatory variable or classified in four categories with average weights of 0.7 g (n¿=¿116), 4.0 g (n¿=¿58), 8.2 g (n¿=¿57) and 14.2 g (n¿=¿23). The inverse relation between percentage of fish with metacercariae and fish weight is reflected in lower percentages of infected fish at higher weights [%infected¿=¿100/(1¿+¿e[-2.02+0.15 fish weight (g)]); p¿