Sierra Nevada Aquatic Research Laboratory

13 Jun, 11 AM - 15 Sep, 05 AM

Emerging infectious diseases can have dramatic effects on host populations. Factors such as host susceptibility and pathogen virulence can markedly alter disease outcomes, and can be the difference between host extinction or persistence. Unfortunately, such factors are often poorly understood, hampering the ability to predict the effect of emerging diseases. Chytridiomycosis is an emerging infectious disease of amphibians caused by the fungal pathogen, Batrachochytrium dendrobatidis (referred to hereafter as ?Bd?). Since its discovery in 1998, chytridiomycosis has been implicated as a major cause of amphibian population declines and extinctions around the world. Many amphibians are highly susceptible to chytridiomycosis, and infection frequently results in host extinction. At the current rapid rate of global Bd spread, many amphibian populations will become infected within the next decade, and this will likely result in substantial numbers of species extinctions in this already-imperiled group of organisms. The western United States is a hotspot of amphibian declines, and many of these declines are associated with chytridiomycosis. In California?s Sierra Nevada mountains, Bd is rapidly spreading through previously uninfected amphibian populations. The mountain yellow-legged frog (Rana muscosa) is highly susceptible to chytridiomycosis, and has experienced hundreds of recent population extinctions due to Bd infection. Interestingly, although the majority of host populations are driven extinct following the arrival of Bd, a small fraction of populations persist with the pathogen, and disease dynamics in these persistent populations are fundamentally different from those during population crashes. The goal of the proposed research is to understand the mechanisms leading to these contrasting disease outcomes. In the proposed research, a model of the R. muscosa/Bd interaction that includes within-host Bd dynamics and host stage-structure will be parameterized and tested. In addition, four non-mutually exclusive hypotheses that could account for different disease outcomes will be tested using field and laboratory experiments. It is hypothesized that population extinction versus persistence is the result of between-population differences in (1) density-dependent disease dynamics, (2) Bd virulence, (3) frog susceptibility, or (4) environmental conditions. A functional genomics approach that utilizes complete Bd and frog genome sequences will be used to describe the genetic basis of any observed differences in Bd virulence and/or frog susceptibility. All of my research activities in 2010 on this project will take place in Sequoia, Kings Canyon, and Yosemite National Parks. The proposed research will contribute significantly to the ability to predict outcomes of future diseases on wildlife and human populations.

Visit #20589 @Sierra Nevada Aquatic Research Laboratory

Approved

Under Project # 9518 | Research

Factors allowing amphibian persistence following disease outbreaks

research_scientist - University of California, Santa Barbara

Reservation Members(s)

Group of 2 Research Assistant (non-student/faculty/postdoc) Jun 13 - Sep 15, 2010 (95 days)

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Dorm 2 Jun 13 - Sep 15, 2010