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Licensed Unlicensed Requires Authentication Published by De Gruyter July 5, 2017

Snail species diversity impacts the infection patterns of Echinostoma spp.: Examples from field collected data

Michael R. Zimmermann, Kyle E. Luth and Gerald W. Esch
From the journal Acta Parasitologica


Rapid losses of biodiversity due to the changing landscape have spurred increased interest in the role of species diversity and disease risk. A leading hypothesis for the importance of biodiversity in disease reduction is the dilution effect, which suggests that increasing species diversity within a system decreases the risk of disease among the organisms inhabiting it. The role of species diversity in trematode infection was investigated using field studies from sites across the U.S. to examine the impact of snail diversity in the infection dynamics of both first and second intermediate larval stages of Echinostoma spp. parasites. The prevalence of Echinostoma spp. sporocysts/rediae infection was not affected by increases in snail diversity, but significant negative correlations in metacercariae prevalence and intensity with snail diversity were observed. Additionally, varying effectiveness of the diluting hosts was found, i.e., snail species that were incompatible first intermediate hosts for Echinostoma spp. were more successful at diluting the echinostome parasites in the focal species, while H. trivolvis, a snail species that can harbor the first intermediate larval stages, amplified infection. These findings have important implications not only on the role of species diversity in reducing disease risk, but the success of the parasites in completing their life cycles and maintaining their abundance within an aquatic system.


We want to acknowledge the Grady Britt Parasitology Fund and the Vecellio Grant at Wake Forest University for financial support of the research.


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Received: 2017-1-10
Revised: 2017-5-17
Accepted: 2017-5-22
Published Online: 2017-7-5
Published in Print: 2017-9-26

© 2017 W. Stefański Institute of Parasitology, PAS

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