While COVID-19 may be the most familiar disease at the moment, beware of Batrachochytrium dendrobatidis (Bd).
The highly infectious fungal pathogen known to target and kill amphibians poses no direct threat to humans; however, its detrimental effects on biodiversity warrant immense concern. Bd and similar diseases, like Batrachochytrium salamandrivorans (Bsal), contribute to a pressing global biodiversity problem. They serve as fuel for additional policy initiatives needed to mitigate these deadly fungi but also target the loss of biodiversity at local, national, and international levels spanning wild, rural, and urban interfaces. There is no “one-size-fits-all” solution to these issues. Therefore, several policy changes are needed to prevent the spread of Bd and similar infectious diseases and help combat the threat of a loss of biodiversity.
An unlikely disappearance
According to professor of biology at University of Maryland, College Park, and self-proclaimed “animal lover,” Karen Lips, Ph.D., “Bd infects over 700 species across three orders of vertebrates, causes species extinctions, mass mortality events and precipitous and persistent population declines where it has invaded.” Lips has spent her life tracking Bd’s impact on frogs throughout Central America in countries like Costa Rica and Panama.
In the 1980s, Lips first discovered the disappearance of amphibians in those concentrated areas. It began with the golden toad in Costa Rica. “When it first disappeared, people didn’t know why,” Lips said. The sites she was researching were secured, protected, and remote, so a disappearance like this was strikingly unusual. She first blamed the weather, but the decline in species was too drastic.
When Lips returned to Central America in the 1990s, frog numbers were abnormal and her research team found “dozens of dead or dying animals,” on their paths of study. They were quickly able to determine that it was Bd that was killing off the frog population, or rather, a catalyst for their extinction. Bd is an invasive species with zoospores, rounded, water-borne cells that help to move bacteria around the species. According to scholars at Global Change Biology, zoospores spread Bd by settling on the frog and entering the cells of the skin, ultimately causing a fatal cardiac arrest. Lips calls these zoospores “little balls,” yet despite their benign nickname, they make it especially easy for Bd to spread and kill off various amphibian species.
Bd ultimately paves the way for an even bigger issue: a catastrophic impact on wildlife biodiversity. “When you remove amphibians from the ecosystem, bugs and tadpoles also disappear, and as a result, entire ecosystems shift,” Lips said. During her research, Lips also discovered other indirect effects of Bd on human health. After the frogs disappeared in Costa Rica and Panama, there was a 10-year increase in the number of malaria cases.
Old laws, new fungi
Bd is already in the United States and while there isn’t a definitive way to cure populations with the disease on a global scale, the further spread of Bd can be prevented. The U.S. Fish and Wildlife Service (FWS) is actively monitoring the spread of Bd through many ways such as activating first responders to mitigate the impact, said Meghan Snow, FWS staff member. These efforts are making headway, but only on a small scale. For instance, Snow described that biologists are helping frogs fight the deadly fungus, but they’re focused in California. The Bd epidemic needs more large-scale change. Not only do these mitigation efforts need to continue, but there needs to be an increase in regulating the trade of these infected species.
Enter: The Lacey Act. Introduced by Iowa Congressman John Lacey in 1900 after a noticeable decline in North America’s wild game species, the Lacey Act prohibits the “trade of any species taken in violation of international or domestic law” and regulates the import of injurious wildlife, according to The Wildlife Society. While this may seem like a good sign for stopping the spread of Bd, the list of animals is small and the sad fact is that most species are unregulated. According to Lips, she nearly “had to beg FWS to add more animals.”
In 2013, researchers discovered a new chytrid fungus known as Bsal. Much like how Bd attacks the skin of frogs, Bsal attacks the skin of salamanders. Because North America is “the global hotspot for salamanders,” noted Lips, the FWS placed a ban on the import of 201 salamander species under the Lacey Act in 2016. According to a recent article featuring Lips in The Atlantic, Bsal has not been detected in North America. Bd, on the other hand, is already present in many areas of the United States. While the salamander ban under the Lacey Act acts as a preventative measure to stop the potential spread of Bsal, there lies a gap in policy to make effective strides towards mitigating Bd, which Lips believes to have been pushed to the sidelines.
Protecting our biodiversity
Approaches to helping solve this problem span wild, rural, and urban interfaces in which Lips outlined many policy initiatives. For instance, on the wild interface front, it’s about placing efforts to reduce deforestation, protect habitats, and increase research on wildlife disease. In the rural interface, it’s increased surveillance on these species and regulating wildlife harvest. For urban interfaces, efforts to create effective vaccines and treatments for amphibians, reduce trade and trafficking, and monitor these invasive diseases are key.
Other approaches stem from a need to quantify the value of nature, Lips said. “Currently, we don’t have a system in the U.S. to document all the species,” she said. “You need to know how many exist and how good they’re doing before you can measure their value.” There are still a lot of unknown gaps in biodiversity. Compiling tangible lists of species is a way to close these gaps, as lists help people visualize the impact of biodiversity crisis.
Under the current administration, a Climate and Environment Division was created to underscore their very commitment to tackling the climate crisis and biodiversity loss. In 2021, the White House Office of Science and Technology Policy (OSTP), added five new experts in biodiversity to the division, including Heather Tallis, Ph.D. Previously, Tallis worked with the Natural Capital Project, a platform striving towards quantifying the value of nature.
The Bd epidemic is just one of the many catalysts for a loss in biodiversity. The hard truth is that the world is facing a huge biodiversity crisis. Bd and Bsal are just contributors, so any efforts to mitigate the spread of these deadly fungi can help immensely in moving the needle towards a brighter future for the environment. “It’s not just about the frogs,” Lips said, “it’s also about the importance of protecting biodiversity.”
It can be especially hard to grasp the personal impact of a loss of biodiversity as a result of these species-destroying fungi. If there’s anything that the COVID-19 pandemic has proven, it’s that understanding a global spread of disease is important and that the management of emerging infectious diseases at national and international scales requires close attention. But, it’s not just about COVID-19, it’s also about the epidemics that are silently killing amphibians and ultimately biodiversity.