Epidermal cell death in frogs with chytridiomycosis
Laura A Brannelly1, Alexandra A Roberts1, Lee F Skerratt2
1One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University , Townsville , QLD , Australia.
Peerj
|February 8, 2017
Summary
Amphibian chytridiomycosis, caused by a fungal pathogen, increases epidermal cell death. This cell death is linked to infection severity and disease progression, suggesting a role in amphibian decline.
Area of Science:
- Amphibian pathology
- Ecology and conservation
- Infectious diseases
Background:
- Amphibian populations are rapidly declining globally.
- Chytridiomycosis, a fungal disease, is a major driver of amphibian loss.
- The disease impacts amphibian skin, but cellular changes remain poorly understood.
Purpose of the Study:
- To investigate the role of apoptosis (programmed cell death) in amphibian skin during chytridiomycosis.
- To quantify cell death in endangered amphibian species experimentally infected with the chytridiomycosis pathogen.
Main Methods:
- Experimentally infected *Pseudophryne corroboree* and *Litoria verreauxii alpina* with the chytridiomycosis fungus.
- Quantified epidermal cell death using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and caspase 3/7 assays.
Main Results:
- Increased cell death correlated positively with fungal infection load and amphibian morbidity.
- TUNEL-positive cells were localized to infected epidermal layers.
- Caspase activity rose sharply in non-recovering animals as infection peaked, but returned to normal in recovered individuals.
Conclusions:
- Fungal infection elevates epidermal cell death, potentially impairing skin function and contributing to amphibian decline.
- The pathogen may initially suppress apoptosis to establish infection.
- Further research is needed on apoptosis regulation during fungal infections in amphibians.
