Meeting Abstract
As adults, acanthocephalans are parasites of vertebrate hosts but use arthropods as intermediate hosts. Some species of acanthocephalans use an additional paratenic host in the life cycle, usually a vertebrate host, where juvenile acanthocephalans survive without further development. However, freshwater snails have occasionally been reported as paratenic hosts for acanthocephalans (Neoechinorhynchus spp.) which infect freshwater turtles as definitive hosts and ostracods as intermediate hosts. In a snail survey from 9 locations in Stillwater, Oklahoma, we found juvenile Neoechinorhynchus sp. infecting the freshwater snail (Helisoma trivolvis). Prevalence ranged from 0% to 70%, depending on the location sampled. To identify this acanthocephalan to species, we amplified 1600 base pairs of the 18S rRNA gene and compared this sequence to an adult acanthocephalan recovered from a red-eared slider turtle. These sequences were genetically identical (100% base pair match). These results indicate that H. trivolvis is a new snail host for N. emydis. More importantly, the size of juveniles from snails in this study indicates that they are much larger than previous reports of Neoechinorhynchus spp. from ostracods, suggesting that worms grow in snail hosts which has important implications on survival as adults in final turtle hosts. Finally, of the 72 Neoechinorhynchus sp. recovered from snail hosts, 60% were encysted in the foot of snails, whereas 40% were attached with their proboscis on the mantle collar under the shell. These attached individuals had characteristics similar to adult worms recovered from turtles, suggesting that they are using snails as definitive hosts.
