Effect of Echinostoma caproni infection on survival, growth, and fecundity of juvenile Biomphalaria glabrata

The effect of Echinostoma caproni infection on survival, growth, and fecundity of juvenile Biomphalaria glabrata was studied. Of 40 juvenile snails (4 +/- 0.2 mm in shell diameter) exposed to 5 miracidia each, 24 were alive at 6-wk postexposure (PE) and 16 of these were infected with E. caproni larvae. Of 40 size-matched control snails maintained identically to the experimental snails except for miracidial exposure, 35 were alive at the end of the 6-wk observation period. The significantly greater survival rate of the control snails suggested that parasitism with larval E. caproni adversely affected snail survival. Exposure to E. caproni miracidia did not alter the growth of juvenile B. glabrata since there was no significant difference in shell diameter of exposed and control snails during the 6-wk observation period. The number of snail egg masses among the unexposed snails was 3.5 to 5.5 times greater than that of exposed snails, suggesting that infection with E. caproni adversely affected fecundity in B. glabrata.