I’ve decided to try to get back into some regular blogging and since I’ve been in contact with so many cool scientists lately, I’d like to start with a little mini-interview with Keely “HK” Smith, who studies amphibian chytrid fungus. Yes, that’s right, chytrid isn’t just a monster I made up for my comic, but a real, living thing, affecting amphibians all over the world. So, here we go:
1. Hi Keely, could you tell us a little about yourself and your current research?
Hi Ethan, I currently work on my PhD at the University of Gent in Belgium (before that I worked in Switzerland and the UK but was born and raised on the west coast of Canada).
I work mainly with fire salamanders (Salamandra salamandra), of which there are quite a few large populations here in East Flanders. Basically, I look at various aspects of salamander immunity and how it varies when dealing with chytrid, to try and gain better insight into their defenses.
2. What is chytrid fungus? How many kinds are there? Which ones are affecting amphibians?
There are about a 1000 different chytrid fungi, all of which live in wet environments. Most are saprobes, which leave off dead matter but a few are parasites.
There are only two chytrids that are known to be parasites of amphibians, both live in water and have motile zoospores that swim and embed themselves in the skin of the amphibians.
The two main species that affect amphibians, Batrachochytrium dendrobadtidis or Bd for short and Batrachochytrium salamandrivorans or Bsal.
Bd affects most amphibian species and has been found all over the world and Bsal was more recently discovered in Europe and only affects salamanders and newts. Bsal originate in Asia where the salamanders are naturally resistant to it. But it was brought to Europe via the pet trade and has cause the collapse of a fire salamander population in the Netherlands and has now been found in Germany and Belgium.
3. Why is chytrid affecting amphibians now? How is it spread?
There are lots of theories around why it is affecting them now. In the case of Bsal this is easily linked to the amphibian pet trade. Asian salamanders have had a long time to develop defenses against the fungus but when you expose it to a naïve populations the effect is disastrous.
For Bd, it is less clear, we still aren’t sure where it originated. But we have found that there are different lineages of Bd. Endemic lineages have been found in many areas and these don’t appear to cause many problems but there is a global panzootic lineage (GPL) which is causing most of the problems. It is hypervirulent and has spread all over the world.
4. Is there anything we can do? Any hope? Natural resistance?
You can learn about the signs for both Bd and Bsal, if you see them in either your own animals or in the wild they can be tested. It’s important not to release any captive animals into the wild, or even any of the water from tanks etc into the water ways. If you see sick animals report them straight away. For Bsal there are several tasks forces set up that are monitoring the spread.
As Bsal has only been found in Europe so far, if we are careful we might be able to stop the spread to North America which has the biggest biodiversity of salamanders.
As far as resistance goes, this differs from species to species. America Bullfrogs (Lithobates catesbeianus) for instance are resistant to Bd, as these animals are traded globally they are thought to be partly responsible for spread. Some are tolerant, like European water frogs, (Pelophylax esculentus), they can become infected but do not develop any symptoms. But maybe species are susceptible, particularly to the Bd GPL lineage.
Bsal has a very strong impact on various salamanders but again there is a difference in susceptibility among species. We are currently working on learning more about this and how we might go about preventing the spread and/or protecting species.