Identification problems with species in the Echinoparyphium recurvatum complex from physid snails in the USA.

This study was done to help us answer numerous requests that we get about the identity of 45-collar-spined echinostomes in the genus Echinoparyphium. We examined 45-collar-spined cercariae from physid snails collected in Europe and the USA. Morphological observations of these cercariae showed considerable similarities in most of the characteristics we examined in these cercariae. Similar findings were made of adults obtained from natural and experimentally infected avian hosts in Europe and the USA. We suggest that these echinostomes be considered as species in the Echinoparyphium recurvatum complex, until further morphological and molecular studies be done on this group.