Emerging Pathogens and a Current-Use Pesticide: Potential Impacts on Eastern Hellbenders

Area of Science:

• Amphibian toxicology
• Disease ecology
• Conservation biology

Background:

• Eastern hellbender (Cryptobranchus alleganiensis alleganiensis) populations are declining.
• Emerging pathogens and pesticides are suspected contributors to population decline.
• Limited empirical data exists on the effects of these factors on hellbenders.

Purpose of the Study:

• To investigate the individual and combined effects of Batrachochytrium dendrobatidis (Bd), a frog virus 3-like ranavirus (RV), and glyphosate herbicide on subadult hellbender survival.
• To assess the skin mucosome's ability to inactivate Bd and RV.

Main Methods:

• Subadult hellbenders were exposed to Bd, RV, a combination of both, or each pathogen after glyphosate exposure.
• Skin mucosome's inactivation of Bd and RV was tested in growth assays.
• Survival rates and causes of mortality were monitored via histopathology.

Main Results:

• Skin mucosome significantly inactivated RV (40% reduction) but not Bd.
• All treatments involving RV exposure led to reduced survival.
• The combination of RV and glyphosate resulted in 100% mortality.
• Bd exposure alone did not cause mortality or infection.

Conclusions:

• Ranavirus (RV) poses a significant threat to subadult hellbender survival.
• Glyphosate herbicide may exacerbate RV-induced mortality in hellbenders.
• Further research is needed to understand the synergistic effects of environmental contaminants and pathogens on amphibian populations.