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Relationship of tadpole stage to location of echinostome cercaria encystment and the consequences for tadpole survival

Journal of Parasitology

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, ORCID iD , and
https://doi.org/10.1645/0022-3395(2003)089[0475:ROTSTL]2.0.CO;2

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Abstract

The effect of echinostome infections on the survival of Rana pipiens tadpoles was examined in relation to developmental stage of tadpoles. Individual tadpoles of Gosner stages 25, 27, 32–33, and 37–39 were exposed to 1 of 4 levels of cercariae (0, 20, 50, or 100). Only tadpoles at stage 25, the earliest stage infected, died within a 5-day experimental period. This stage-specific mortality rate could be explained, in part, by the stage-specific location of encystment of cercariae, which was documented in a separate experiment. In accordance with kidney development, cercariae predominately encysted in the pronephroi during early stages of tadpole development (stages 25 through 31–32) and only in the mesonephroi and associated ducts at later stages (stages 37 through 46). As the mesonephros develops, renal capacity presumably increases. Thus, tadpoles died only when metacercariae concentrated in the functional portion of the kidney with the most limited renal capacity. As tadpoles aged, they also became less susceptible to infections. On average, 69.5% of cercariae that were exposed to stage 25–26 tadpoles successfully encysted, compared with only 8.4% of cercariae exposed to stage 37–38 tadpoles. Exposures of metamorphic frogs (poststage 46) to cercariae revealed that these individuals can become infected with echinostomes. Collectively, our data highlight the host stage–dependent dynamics of tadpole–echinostome interactions.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Relationship of tadpole stage to location of echinostome cercaria encystment and the consequences for tadpole survival
Series title:
Journal of Parasitology
DOI:
10.1645/0022-3395(2003)089[0475:ROTSTL]2.0.CO;2
Volume:
89
Issue:
3
Year Published:
2003
Language:
English
Publisher:
American Society of Parasitologists
Contributing office(s):
National Wildlife Health Center
Description:
8 p.
First page:
475
Last page:
482