A study of the relationship between the energy contents of Schistosoma mansoni cercariae and their death during penetration of mammalian host skin.

Immersion of Biomphalaria pfeifferi in 1.5% glucose solution showed that the snails did not absorb any glucose during the first six hours but that almost 30% of the glucose was absorbed after 24 hours. The glycogen content of such "glucose-fed" snails was much higher than that of control normal snails. Cercariae of S. mansoni collected from the former snails exhibited a much lower level of death (20%), during penetration of mouse skin, than that of control normal cercariae (36%). It is suggested that death of S. mansoni cercariae during penetration of mammalian host skin is probably due to exhaustion of their energy reserves.