Herbicide Atrazine Exposure Increases Risk of Deadly Fungal Disease for Frogs

A recent study shows that the combination of the herbicide atrazine and a fungal disease can be particularly deadly to frogs.

Researchers from the University of South Florida worked to investigate the global demise of the amphibian populations.

According to USF Biologist Jason Rohr, new findings show that early-life exposure to atrazine can increase a frog's mortality due to chytrid fungus, a pathogen that's been linked to worldwide amphibian declines.

"Understanding how stressors cause enduring health effects is important because these stressors might then be avoided or mitigated during formative developmental stages to prevent lasting increases in disease susceptibility," Rohr said, via a press release.

Various experiments involved a six-day exposure to environmentally relevant concentrations of atrazine. This is one of the most common herbicides in the world that increased frog mortality 46 days after the atrazine exposure. However, this only occurred when frogs were challenged with the chytrid fungus. The increase in mortality was determined by a reduction in the frog's tolerance due to infection.

Yet the researchers found no specific evidence of recovery from the atrazine exposure.

"These findings are important because they suggest that amphibians might need to be exposed only to atrazine briefly as larvae for atrazine to cause persistent increases in their risk of chytri-induced mortality," Rohr said, via the release. "Our findings suggest that reducing early-life exposure of amphibians to atrazine could reduce lasting increases in the risk of mortality from a disease associated with worldwide amphibian declines."

The findings of the study suggest that while this chemical does not directly kill amphibians and fish, it negatively harms the biology of the animals' growth and immune and endocrine systems.

More information regarding the study can be found via the Proceedings of the Royal Society B.