MODES OF ENTRY OF THE FIRST-STAGE LARVAE OF ELAPHOSTRONGYLUS-CERVI (NEMATODA, PROTOSTRONGYLIDAE) INTO PULMONATE SNAILS ARIANTA-ARBUSTORUM AND HELIX-POMATIA

Experimental infection of the pulmonate snails Arianta arbustorum L. a nd Helix pomatia L. with first-stage larvae of protostrongylid nematod e Elaphostrongylus cervi Cameron, 1931 was performed in order to deter mine modes of larval entry into the body of the snail intermediate hos t. Groups by four individuals of both snail species were examined hist ologically 30, 60, 90, and 120 minutes after the beginning of exposure and 1, 2, 4, and 7 days post infection. All 64 snails examined were f ound to be successfully infected. The superficial furrows of the sole were recognized as the most important site of larval entry into the sn ail organism. Larval penetration was observed to be accompanied by des truction of the superficial epithelium. The number of larvae found in the subepithelial connective tissue of the headfoot was significantly higher than that found in other tissues and organs. Larval counts in i ndividual parts of the body of snails examined from 0 to 7 days p.i. d id not fluctuate significantly.;The present results indicate that only those protostrongylid larvae which actively penetrated the superficia l epithelium of the snail sole play an important role in the life cycl e.