A host of spore-producing parasites may be waiting in the wings for a chance to attack amphibians.

Albino African Clawed Frogs
Albino African Clawed Frogs (Xenopus laevis) for sale in Hong Kong. This species is known to carry diseases that can cause declines in other amphiiban species. Image: Jodi Rowley
© Jodi Rowley

If you’ve heard of a parasite affecting amphibians, chances are it’s the amphibian chytrid, also known as Batrachochytrium dendrobatidis or ‘Bd’ for short. But that’s not the only parasite out there…

The fact that the amphibian chytrid is rather well-known is deserved. It’s a zoospore-producing fungus capable of infecting the skin of amphibian species and causing the disease chytridiomycosis. Bd damages the skin of amphibians, causing electroltye imbalance which often leads to cardiac arrest and death.This disease is implicated in driving a number of frog species in Australia and Central America extinct, totally wiping them off the face of the earth.  It’s not surprisingly, then, that there’s been a lot of scientific attention directed towards this particular parasite.

But unfortunately, there’s evidence to suggest that the amphibian chytrid may not always act alone, and that it may be just the tip of the iceberg for amphibians as far as parasites go. With freshwater fishes and amphibians being transported around the world by us humans, and often released into new habitats, parasites from the other side of the world are being inadvertently released into freshwater habitats, with the potential to infect native amphibians.

The amphibian chytrid is one zoosporic parasite, but many other parasites have the same kind of effective ‘weapons’ against amphibians. They infect amphibians via zoospores, which are released into aquatic environments in large numbers and can swim for hours in search of their amphibian hosts. They often attack the skin of amphibians, which is somewhat of an Achilles’ heel for amphibians, and they may also infect a wide range of other freshwater creatures, ensuring that they can lurk in streams and ponds even when amphibians aren’t around.

A wide array of zoosporic parasites may be poised to impact amphibian diversity in the future. And it’s likely that it won’t just be a single parasite that they’ll have to deal with. Even now, it’s likely that amphibians around the world are being exposed to numerous parasites, many of which have been transported around the globe by us humans. These parasites are likely to compound the threats already facing amphibians such as habitat loss, climate change and pollution.

We’re quite literally going to have to watch amphibians’ backs to ensure that they survive.

Dr Jodi Rowley
Coordinator, Australian Museum Research Institute

More information:
Gleason, F.H., Chambouvet, A., Sullivan, B.K., Lilje, O., & Rowley, J.J.L. (2014). Multiple zoosporic parasites pose a significant threat to amphibian populations. Fungal Ecology.