Sierra Nevada Aquatic Research Laboratory

23 Jun, 03 PM - 24 Aug, 02 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. The proposed research will contribute significantly to the ability to predict outcomes of future diseases on wildlife and human populations. Broader impacts: The proposed research will have considerable impact beyond academia. Results from the research will be directly relevant to the conservation of amphibians worldwide that are threatened by disease, and will likely be broadly used to inform conservation strategies and policy initiatives. To ensure the rapid incorporation of results into such efforts, results will be communicated to policy makers via (i) continued participation by project researchers in an R. muscosa recovery working group, (ii) annual meetings with federal and state agencies charged with R. muscosa conservation (e.g., National Park Service, U. S. Fish and Wildlife Service, California Department of Fish and Game), and (iii) consultation with non-governmental organizations developing amphibian conservation programs worldwide. The project will promote teaching and training of a diverse group of students and postdoctoral researchers in modeling, genomics, molecular genetics, statistics, and laboratory and field methods through their direct involvement in the research. To provide Bd-specific training to a wider audience, three workshops targeted at federal and state agency biologists and private consultants will be hosted during the project in collaboration with the Amphibian Specialist Group (IUCN, World Conservation Union). Sampling protocols (in text and video formats) will also be provided online in both English and Spanish. Achieving these broader objectives will be made possible by the wide range of partnerships and collaborations developed by this research group during the previous EID-funded project.

Visit #15628 @Sierra Nevada Aquatic Research Laboratory

Approved

Under Project # 10198 | Research

After the Crash: Factors allowing Host persistence following outbreaks of a highly virulent disease

faculty - San Francisco State University (CSU)

Reservation Members(s)

Vance Vredenburg Jun 23 - Aug 24, 2008 (63 days)
Group of 5 Volunteer Jun 23 - Aug 24, 2008 (63 days)

Reserve Resources(s) | Create Invoice

Dorm 9 Jun 23 - Aug 24, 2008
Q8 9 Jun 23 - Aug 24, 2008