Left to Right: Tabby Cavendish (Great Smoky Mountains NP), Brian Gregory (USGS), and Jamie Barichivich (ARMI) swabbing salamanders for Batrachochytrium dendrobatidis (Bd) in Rockhouse Cave, Wheeler NWR, Alabama. Photo by: Alan Cressler.
ARMI conducts original research on various amphibian diseases in the lab and field. Our research has included estimating the impacts of diseases on the growth of populations, developing and testing potential treatments, affects of stressors on susceptibility to disease, how diseases are transmitted in the wild, and how to model disease distributions and spread.
ARMI disease research is conducted throughout the country, but ARMI pathologist Dr. David Green is based at the National Wildlife Health Center in Madison, Wisconsin, and coordinates the health screenings and investigations of amphibian mortalities (e.g., identification, pathology) in addition to collaborating on many disease research projects.
Amphibians at our long-term monitoring sites are periodically screened for diseases and we investigate mass mortality events.
National Wildlife Health Center - ARMI
ARMI Products on Disease
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Restored agricultural wetlands in central Iowa: habitat quality and amphibian response
Authors: Reeves RA, Pierce CL, Smalling KL, Klaver RW, Vandever MW, Battaglin WA, Muths E | Date: 2016-02 | Outlet: Wetlands | Format: .PDF
Amphibians are declining throughout the United States and worldwide due, partly, to habitat loss. The Iowa Conservation Reserve Enhancement Program (CREP) strategically restores wetlands to denitrify tile drainage effluent and restore ecosystem services. Understanding how eutrophication , hydroperiod, predation, and disease affect amphibians in restored wetlands is central to maintaining healthy amphibian populations in the region. We examined the quality of amphibian habitat in restored CREP wetlands relative to reference wetlands by comparing species richness, developmental stress, and adult leopard frog (Lithobates pipiens) survival probabilities to a suite of environmental metrics. Although measured habitat variables differed between restored and reference wetlands, differences appeared to have sub-lethal rather than lethal effects on resident populations . There were few differences in amphibian species richness and no difference in estimated survival probabilities between wetland types. Restored wetlands had more nitrate and alkaline pH, longer hydroperiods, and were deeper, whereas reference wetlands had more amphibian chytrid fungus zoospores and resident amphibians exhibited increased developmental stress. Restored and reference wetlands are both important components of the landscape in central Iowa and maintaining a complex of fish-free wetlands with a variety of hydroperiods will likely contribute to the persistence of amphibians in this landscape.
Experimental evidence for American bullfrog (Lithobates catesbeianus) susceptibility to chytrid fungus (Batrachochytrium dendrobatidis)
Authors: Gervasi SS, Urbina J, Hua J, Chestnut T, Relyea RA, Blaustein AR | Date: 2013-03-29 | Outlet: EcoHealth DOI: 10.1007/s10393-013-0832-8 | Format: URL
The emerging fungal pathogen, Batrachochytrium dendrobatidis (Bd), has been associated with global amphibian population declines and extinctions. American bullfrogs (Lithobates catesbeianus) are widely reported to be a tolerant host and a carrier of Bd that spreads the pathogen to less tolerant hosts. Here, we examined whether bullfrogs raised from eggs to metamorphosis in outdoor mesocosms were susceptible to Bd. We experimentally exposed metamorphic juveniles to Bd in the laboratory and compared mortality rates of pathogen-exposed animals to controls (non-exposed) in two separate experiments; one using a Bd strain isolated from a Western toad and another using a strain isolated from an American bullfrog. We wanted to examine whether metamorphic bullfrogs were susceptible to either of these strains. We show that bullfrogs were susceptible to one strain of Bd and not the other. In both experiments, infection load detected in the skin decreased over time, suggesting that metamorphic bullfrogs from some populations may be inefficient long- term carriers of Bd.
Prevalence of the amphibian chytrid fungus (Bd) at Buenos Aires National Wildlife Refuge, Arizona
Authors: Sigafus B, Schwalbe C, Hossack B, Muths E | Outlet: Herpetological Review | Format: .PDF
Prevalence of the amphibian chytrid fungus on Buenos Aires National Wildlife Refuge is low. Very few bullfrogs (a carrier of Bd) on the refuge test positive and very few Chiricahua Leopard Frogs test positive (only at sites off of the refuge). Bullfrogs have been nearly eradicated from the refuge, but because they carry the disease, there is potential for bullfrogs to act as a vector, carrying the disease to the Chiricahua Leopard Frogs which are an endangered species if they move back onto the refuge.