Endemic Infection of the Amphibian Chytrid Fungus in a Frog Community
Post-Decline

Richard W. R. Retallick1 2 3 , Hamish McCallum2* , Rick Speare4

1 School of Tropical Biology, James Cook University, Townsville, Queensland,
Australia, 2 Department of Zoology and Entomology, University of Queensland,
St Lucia, Queensland, Australia, 3 School of Life Sciences-Biology, Arizona
State University, Tempe, Arizona, United States of America, 4 Amphibian
Diseases Group, School of Public Health and Tropical Medicine, James Cook
University, Townsville, Queensland, Australia

The chytrid fungus Batrachochytrium dendrobatidis has been implicated in the
decline and extinction of numerous frog species worldwide. In Queensland,
Australia, it has been proposed as the cause of the decline or apparent
extinction of at least 14 high-elevation rainforest frog species. One of
these, Taudactylus eungellensis, disappeared from rainforest streams in
Eungella National Park in 1985-1986, but a few remnant populations were
subsequently discovered. Here, we report the analysis of B. dendrobatidis
infections in toe tips of T. eungellensis and sympatric species collected in
a mark-recapture study between 1994 and 1998. This longitudinal study of the
fungus in individually marked frogs sheds new light on the effect of this
threatening infectious process in field, as distinct from laboratory,
conditions. We found a seasonal peak of infection in the cooler months, with
no evidence of interannual variation. The overall prevalence of infection
was 18% in T. eungellensis and 28% in Litoria wilcoxii/jungguy, a sympatric
frog that appeared not to decline in 1985-1986. No infection was found in
any of the other sympatric species. Most importantly, we found no consistent
evidence of lower survival in T. eungellensis that were infected at the time
of first capture, compared with uninfected individuals. These results refute
the hypothesis that remnant populations of T. eungellensis recovered after a
B. dendrobatidis epidemic because the pathogen had disappeared. They show
that populations of T. eungellensis now persist with stable, endemic
infections of B. dendrobatidis.

Full Text at PLoS Biology
http://www.plosbiology.org/plosonline/?request=get-document&doi=10.1371/journal.pbio.0020351

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