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Abstract To combat the loss of species due to emerging infectious diseases, scientists must incorporate ecological parameters, such as temperature and humidity, to understand how the environment affects host–pathogen interactions. The fungal disease chytridiomycosis is a compelling case study to investigate the role of both temperature and humidity on infectious disease, as both the fungal pathogen (Batrachochytrium dendrobatidis, Bd) and the host (amphibians) are heavily influenced by these abiotic factors. We performed two experiments to investigate the importance of relative humidity and temperature on frog immunity (production of antimicrobial skin secretions) and disease development in captive golden frogs (Atelopus zeteki) of Panama. We found that the quantity of skin secretions significantly decreased over time in frogs moved from low to medium and high relative humidity treatments. FollowingBdexposure, frogs in high temperature (26–27 °C) and high relative humidity (80–90%) had lower pathogen loads and survived significantly longer than frogs kept in all other treatment conditions, including high temperature and low relative humidity. These results suggest that high relative humidity may be an important, although less understood, mediator ofBdinfection and the survival of golden frogs. Because the environment can drastically alter disease dynamics, understanding how temperature and humidity influence chytridiomycosis outcomes in golden frogs may be essential for the success of the reintroduction of captive frogs.
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This content will become publicly available on February 23, 2027
Amphibians' Expansion to Record Elevations Influences Chytrid (Batrachochytrium dendrobatidis) Infection Dynamics
The climate-driven range expansion of host species could impact emerging infectious disease events through several mecha-nisms, with repercussions for conservation and public health. For instance, infection outcomes may be affected by the differentresponses of hosts and pathogens to new environments. Additionally, range expansions may create novel transmission opportu-nities as host movement patterns change. Here, we use an integrative approach to explore how the infection dynamics of Marbledfour-eyed frogs (Pleurodema marmoratum) with the pathogen Batrachochytrium dendrobatidis (Bd) have been impacted by theirelevational range expansion in the Cordillera Vilcanota, Peru. With field surveys, we establish that range expansion creatednew opportunities for Bd transmission: P. marmoratum are now continuously distributed along a recently deglaciated mountainpass between populations separated by heavily glaciated mountains. With sequence data, we identify Bd from the Vilcanota asbelonging to the lineage most frequently associated with amphibian declines (BdGPL) and find that it lacks genetic structuredespite possessing abundant variation, consistent with high rates of local dispersal. With temperature loggers, we demonstratethat upslope expansion exposed frogs and Bd to challenging new thermal regimes. Finally, with size, mass, and Bd infection datafrom adult P. marmoratum, we find that the new elevations colonized may constrain infection intensities and influence sublethalcosts of infection: at low elevations, infected frogs have lower body condition than uninfected frogs, while at high elevations,infected frogs have smaller bodies than uninfected frogs. Together, our results suggest that the climate-driven range shifts of hostspecies may influence pathogen transmission and infection outcomes.
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- Award ID(s):
- 2410553
- PAR ID:
- 10668132
- Publisher / Repository:
- Wiley Online Library
- Date Published:
- Journal Name:
- Biotropica
- Volume:
- 58
- Issue:
- 2
- ISSN:
- 1744-7429
- Page Range / eLocation ID:
- e70165
- Subject(s) / Keyword(s):
- climate change, Cordillera Vilcanota, disease triangle, Peru, range expansion, sublethal effects, synergisms, transmission
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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