Penetration and survival of mesocercariae (Alaria spp.) in the mammalian eye

A Canadian woman presented with a motile, intra-retinal worm, which by appearance and movement was strikingly similar to the mesocercaria of Alaria sp., a trematode from frogs. Using these mesocercariae and rabbits this study set out to establish 1) whether these mesocercariae can penetrate the cornea, 2) how long they might survive within the eye, and 3) what reaction is produced. It was found that some penetrated the cornea readily and, after injection, were capable of prolonged survival within the eye. Little overt reaction was produced though histologically the expected chronic inflammatory reaction with eosinophils occurred.