Document Detail

Information about transmission opportunities triggers a life-history switch in a parasite.
MedLine Citation:
PMID:  14761067     Owner:  NLM     Status:  MEDLINE    
Many microbial pathogens can switch to new hosts or adopt alternative transmission routes as environmental conditions change, displaying unexpected flexibility in their infection pathways and often causing emerging diseases. In contrast, parasitic worms that must develop through a fixed series of host species appear less likely to show phenotypic plasticity in their transmission pathways. Here, I demonstrate experimentally that a trematode parasite, Coitocaecum parvum, can accelerate its development and rapidly reach precocious maturity in its crustacean intermediate host in the absence of chemical cues emanating from its fish definitive host. Juvenile trematodes can also mature precociously when the mortality rate of their intermediate hosts is increased. Eggs produced by precocious adults hatch into viable larvae, capable of pursuing the parasite's life cycle. In the absence of chemical cues from fish hosts, the size of eggs released by precocious trematodes in their intermediate hosts becomes more variable, possibly indicating a bet-hedging strategy. These results illustrate that parasitic worms with complex life cycles have development and transmission strategies that are more plastic than commonly believed, allowing them to skip one host in their cycle when they perceive limited opportunities for transmission.
Robert Poulin
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Evolution; international journal of organic evolution     Volume:  57     ISSN:  0014-3820     ISO Abbreviation:  Evolution     Publication Date:  2003 Dec 
Date Detail:
Created Date:  2004-02-05     Completed Date:  2004-02-20     Revised Date:  2008-06-04    
Medline Journal Info:
Nlm Unique ID:  0373224     Medline TA:  Evolution     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2899-903     Citation Subset:  IM    
Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand.
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MeSH Terms
Amphipoda / parasitology*
Analysis of Variance
Fishes / parasitology*
Fresh Water
Host-Parasite Interactions
Life Cycle Stages / physiology*
New Zealand
Ovum / cytology*
Trematoda / cytology,  growth & development*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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