Effects of snail size on encystment of Echinostoma caproni in juvenile Biomphalaria glabrata (NMRI strain) and observations on the survival of infected snails.
The effects of snail size on encystment of Echinostoma caproni cercariae in neonatal and juvenile Biomphalaria glabrata (NMRI strain) snails were studied. Encystment in neonatal (0.7-1.1 mm shell diameter) and juvenile (2-3 mm shell diameter) snails was compared 24 h post-infection (PI) following individual exposure of snails of each size to 1, 5, 10, 25 and 50 cercariae. Significantly more cysts were recovered from juveniles exposed to 1, 5, 10 and 50 cercariae than from neonatals with comparable exposure. Size of B. glabrata was a major factor in determining cyst burden in this planorbid. Survival of infected versus uninfected neonatals and juveniles was also examined for 7 days. Neonatals exposed to 10 cercariae showed a significant decrease in survival at 3, 6 and 7 days PI when compared to the uninfected controls. There was no significant decrease in the survival of juveniles exposed to 10 cercariae compared to uninfected controls at any time point. Snail size was a factor in mortality associated with echinostome cercarial penetration and encystment.
Department of Biology, Lafayette College, Easton, PA 18042, USA.
J L
JL
Schneck
B
B
Fried
D000818:Animals; D001700:Biomphalaria / Q000469:parasitology*; D049628:Body Size; D004449:Echinostoma / Q000502:physiology*; D007814:Larva