Meeting Abstract
In many acanthocephalan life cycles, a vertebrate paratenic host is used to bridge the ecological gap between the intermediate and definitive hosts. However, there have been few reports of freshwater snails serving as paratenic hosts for acanthocephalans. To assess how commonly freshwater snails serve as hosts for acanthocephalans, two species of freshwater snails, Helisoma trivolvis and Physa acuta, were collected from various wetlands throughout Payne Co., Oklahoma. Additionally, snails were sampled on a monthly basis for a year from a single location to further investigate seasonal variation of infection. Acanthocephalans were identified to Neoechinorhynchus spp., which most likely infect turtle definitive hosts and ostracod intermediate hosts in nature. Depending on the site, prevalence and mean intensity ranged from 4–79% and 1–3.6, respectively. Throughout the year, prevalence and mean intensity peaked at 73% during the summer and decreased to 0% during the winter. We also measured snail egg production in the laboratory to examine differences between acanthocephalan-infected and uninfected field collected snails. Egg production did not differ significantly between infected and uninfected field collected snails. Finally, our histological analyses suggest there is an immunological response by the snail to the parasite, suggesting these acanthocephalans are metabolically active within their snail hosts. These results suggest that 1) location and season have a strong effect on the variation of acanthocephalan infections in snails; 2) acanthocephalans are using two different microhabitats within snail hosts; and 3) acanthocephalans appear to be growing and developing within snail hosts.
