Mitigating amphibian disease: strategies to maintain wild populations and control chytridiomycosis
1 Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
2 Smithsonian Tropical Research Institute, MRC 0580-12, Unit 9100 Box 0948, DPO AA 34002-9998, USA
3 Departamento de Biología Evolutiva y Biodiversidad, Museo Nacional de Ciencias Naturales, CSIC, c/José Gutierrez Abascal 2, 28006 Madrid, Spain
4 Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA 93106-9610, USA
5 School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4811, Australia
6 School of Public Health, Tropical Medicine and Rehabilitation Sciences, Amphibian Disease Ecology Group, James Cook University, Townsville, QLD 4811, Australia
7 Department of Biology, California State University at Bakersfield, Science 1/room 310, 9001 Stockdale Highway, Bakersfield, CA 93311, USA
8 U.S. Geological Survey, Fort Collins Science Center, 2150 Centre Avenue, Bldg C, Fort Collins, CO 80526-8118, USA
9 KARCH, Passage Maximilien-de-Meuron 6, 2000 Neuchâtel, Switzerland
10 Department of Natural Sciences, Carroll College, 1601 North Benton Avenue, Helena, MT 59625, USA
11 Department of Biological Sciences, University of Idaho, Moscow, Idaho 83844 USA
Frontiers in Zoology 2011, 8:8 doi:10.1186/1742-9994-8-8Published: 18 April 2011
Rescuing amphibian diversity is an achievable conservation challenge. Disease mitigation is one essential component of population management. Here we assess existing disease mitigation strategies, some in early experimental stages, which focus on the globally emerging chytrid fungus Batrachochytrium dendrobatidis. We discuss the precedent for each strategy in systems ranging from agriculture to human medicine, and the outlook for each strategy in terms of research needs and long-term potential.
We find that the effects of exposure to Batrachochytrium dendrobatidis occur on a spectrum from transient commensal to lethal pathogen. Management priorities are divided between (1) halting pathogen spread and developing survival assurance colonies, and (2) prophylactic or remedial disease treatment. Epidemiological models of chytridiomycosis suggest that mitigation strategies can control disease without eliminating the pathogen. Ecological ethics guide wildlife disease research, but several ethical questions remain for managing disease in the field.
Because sustainable conservation of amphibians in nature is dependent on long-term population persistence and co-evolution with potentially lethal pathogens, we suggest that disease mitigation not focus exclusively on the elimination or containment of the pathogen, or on the captive breeding of amphibian hosts. Rather, successful disease mitigation must be context specific with epidemiologically informed strategies to manage already infected populations by decreasing pathogenicity and host susceptibility. We propose population level treatments based on three steps: first, identify mechanisms of disease suppression; second, parameterize epizootiological models of disease and population dynamics for testing under semi-natural conditions; and third, begin a process of adaptive management in field trials with natural populations.