New Amphibian Diseases Threaten to Exacerbate Worldwide Decline

Red-spotted newts are one of the North American salamanders susceptible to the new chytrid disease. (Wikimedia Commons)

Red-spotted newts are  susceptible to the new chytrid disease. (Wikimedia Commons)

The decline of the world’s amphibians, in part due to disease caused by the chytrid fungus (Batrachochytrium dendrobatidis), has caused alarm among conservationists, wildlife managers, and herpetologists. Just as treatments for the disease were showing some successes, including boosting immunity through exposure to dead or live pathogens and skin probiotics, two new diseases have been announced in the last year: a new species of chytrid fungus and two new ranaviruses, both discovered in Europe. The chytrid fungus (B. salamandrivorans) was discovered in Bunderbos, The Netherlands in 2013 after a 96% decline in fire salamander populations was observed there. The new ranavirus was found in northern Spain, and caused population crashes for the common midwife toad (Alytes obstetricans), the alpine newt (Mesotriton alpestris), and the common toad (Bufo bufo).

A paper just published in Science showed that the new chytrid fungus is from Asia and identified dozens of susceptible salamander species from Europe and the Americas, as well as three optimal reservoir species that can clear the disease after harboring it–and potentially transmitting it–for months. The researchers found that newts are especially likely to be infected by this disease, and the trade of Asian newts for pets is the most likely way that the disease was introduced to The Netherlands.   

Conservationists are calling for testing and quarantines of potential reservoir species in the pet trade. In the US, which harbors the greatest salamander diversity in the world in the Appalachian Mountains, monitoring is only required for animals crossing borders if they could harbor diseases that pose direct threats to humans and livestock, according to a press release from University of Maryland. Karen Lips of University of Maryland, one of the coauthors on the Science paper, has been working on bringing this issue to policymakers. She wrote a post on the Leopold Leadership 3.0 blog about learning to bring her science to inform policy. Much of her advice resonated with the outcomes of the panel discussion I organized at ESA, especially her point about the time investment necessary to develop trusting relationships between policymakers and scientists. In light of the results from this recent paper, inaction will spell impending declines in salamander populations of the Americas. More scientific and policy developments are likely to emerge in the coming months and years. Stay tuned.

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