Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Proc Biol Sci. 2001 Feb 7;268(1464):251-7.

Trade-offs in the evolution of virulence in an indirectly transmitted macroparasite.

Author information

  • 1Wellcome Trust Centre for the Epidemiology of Infectious Disease, Department of Zoology, University of Oxford, UK. charlotte.davies@wellcome-epidemiology.oxford.ac.uk

Abstract

The adaptive trade-off theory for the evolution and maintenance of parasite virulence requires that virulence be genetically correlated with other fitness characteristics of the parasite. Many theoretical models rely on a positive correlation between virulence and transmissibility. They assume that high parasite replication rates are associated with a high probability of transmission (and, hence, increased parasite fitness), but also with high levels of damage to the host (high virulence). Schistosomes are macroparasites with an indirect life cycle involving a mammalian and a molluscan host. Here we demonstrate, through the development of five substrains, a genetic basis for schistosome virulence. We used these substrains further in order to investigate the presence of parasite fitness traits that were genetically correlated with virulence. High virulence in the (mouse) definitive host was, as predicted, positively correlated with parasite replication. In contrast, in the (snail) intermediate host high virulence was associated with low parasite replication rates. Variation in infectivity to and parasite replication in the definitive host was suggested as a compensating mechanism for the maintenance of virulence in the snail host. This is the first report of a trade-off in parasite reproductive success across hosts in an indirectly transmitted macroparasite.

PMID:
11217894
[PubMed - indexed for MEDLINE]
PMCID:
PMC1088599
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk