DEVELOPMENT OF THE PLEROCERCOID-I OF OPHIOTAENIA-EUROPAEA IN REPTILES

The existence of a two-host life-cycle in ophiotaeniid proteocephalide ans was tested experimentally using Ophiotaenia europaea as a model. T hree species of reptiles, Natrix natrix, Natrix tessellata and Lacerta viridis, were fed with experimentally infected copepods containing a large number of infective plerocercoids I. A few plerocercoids, most o f which were dead, corresponding morphologically to the plerocercoid I I developmental stage of O. europaea, were found encysted in the intes tinal wall of N. natrix (8 days p.i.), N. tessellata (5 and 150 days p .i.) and L. viridis (40 days p.i.), while no plerocercoids or adult wo rms were recovered from their intestines. The results indicate that th e infective plerocercoid I of O. europaea cannot undergo further devel opment when ingested directly by the final host (a reptile), and that environmental temperature stimuli cannot initiate a reverse plerocerco id migration to the gut followed by strobilization. (C) 1997 Australia n Society for Parasitology. Published by Elsevier Science Ltd.