That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information
A bacterium that naturally occurs on the skin of certain frogs and salamanders has been shown to protect these animals from infection by a deadly Chytrid fungus infection. Chytrid fungus, known as Batrachochytrium dendrobatidis, has been very much in the news since its discovery in 1999. It is believed to have caused the extinction of up to 200 amphibian species, and is still spreading in many countries.
A Fungus-Killing Bacterium
The helpful bacterium’s name – Janthinobacterium lividum – is quite a mouthful, but amphibian enthusiasts should keep it in mind. Isolated from the skin of Mountain Yellow-Legged Frogs, Rana mucosa, and Red-Backed Salamanders, Plethodon cinereus (please see photos), this bacterium may turn out to be an invaluable weapon in what has thus far been a losing battle to combat Chytrid-driven extinctions.
Lab Tests and Field Research
As reported in a recent Scientific American article (July 12, 2010), J. lividum can be collected from frog skin and cultured in the lab. Captive frogs and salamanders inoculated with the lab-grown bacterium did not contract Chytrid when exposed to the fungus.
Field research has shown that amphibians with the highest J. lividum populations on their skin had the greatest immunity to Chytrid infection. Later this month, researchers will inoculate wild Mountain Yellow-Legged Frogs in California’s Sierra Nevada Mountains – the first time a treatment strategy of this type will be attempted. It is hoped that J. lividum bacteria released into ponds will colonize amphibian skin without additional assistance. This would alleviate the burden of capturing and inoculating individual animals – a consideration that makes anti-fungal medications impractical for use in the field.
Another promising feature of J. lividum therapy is that the bacterium is a naturally-occurring organism that will not cause adverse side effects.
Further Reading
You can learn more about the devastating consequences of the worldwide Chytrid fungus outbreak in this Amphibian Ark article.
Do we know for certain that it is safe for other species and not just and exclusive fungi to the actual area where it was found? In other words if we release into the wild will it also effect other wildlife?
Hello, Frank Indiviglio here.
Thanks for your interest in our blog. Good point. In this case I believe they are using bacteria cultured from frogs collected in the same pond, and that high levels of the bacteria are normal within the frog’s range. I doubt whether enough is known re introductions to non-native habitats, as the findings are quite new. The situation seems quite desperate in some areas, so risks may be considered. I’ll post updates as more info surfaces.
Best regards, Frank Indiviglio.
That was exactly my concern was about re introductions but it would make sense that if the Chytrid killing bacteria is already there boosting it shouldn’t have an effect. I would be interested to see how amphibians taken out of the wild for preservation purposes would react to being treated and then reintroduced to their native habitats. I know of several areas where desperate wouldn’t begin to say enough. Do we have any idea where or how the origins of Chytrid began yet?
Hello John, Frank Indiviglio here.
Thanks for the feedback.
Chytrid has been found in preserved African Clawed Frogs dating back to at least the 1940’s. Some theorize that it was spread worldwide when these frogs were shipped out of Africa for use in pregnancy testing in the 40’s and 50’s. However, that doesn’t explain the apparent changes in its effect on so many species so suddenly, and in such a short span of time.
Best regards, Frank Indiviglio.
I had heard about the pregnancy experiments and I thought that was a really odd reason for it take that long to develop as a vector that would move so fast but then again I know of at least two wild populations of African Clawed Frogs here where I live in a canal system. So I would presume it to be waterborne but I have no data to back that up. Either way I am glad to hear that we finally have something to combat the Chytrid fungus and wish the scientists working on it all the best. We cannot lose our amphibian species.
Hello John, Frank Indiviglio here.
Thanks for your thoughts. Yes, they have been breeding all over the world since quicker methods of pregnancy testing evolved – brackish ponds in the UK, Brazil, the Rio Grande – you name it! The thinking on the current situation is that environmental factors may now pre-dispose amphibs to becoming infected – i.e. immune system stressed by pollution, climate, disturbance. Others believe that the fungus may have evolved into something more potent, just as bacteria have in hospitals, etc. But of course the fact that so many species are involved in different habitats is disturbing and makes any one explanation seem implausible.
Good luck and please keep me posted.
Best regards, Frank Indiviglio.
Yes, I would have to agree with that. One explanation does in fact seem implausible. Well, I guess for no all we can do is hope and do our best to understand the bacteria and its life cycle and attempt to correct what we may brought on ourselves.
Hello John, Frank Indiviglio here.
Thanks for the feedback; I sometimes am hesitant to accept “doomsday” predictions, because, for example, “extinct” animals sometimes turn up in large numbers in war-torn regions once calm is restored (gorillas), etc. I’ve read studies that indicate that in order to properly understand fluctuations in great gray kangaroo populations you need to look at 100 year long patterns of rain, grass growth and births – anything less gives a false reading…but the Chytrid situation does indeed seem to be a very grave emergency.
Good luck and please keep me posted.
Best regards, Frank Indiviglio.
Very true, extinct species seem to pop back up in the most unusual places.
Hello John, Frank Indiviglio here.
Some years ago the Giant Flying Squirrel (a nearly 4-foot long nocturnal squirrel that lives I the Himalayas) was declared “most likely extinct”. Then an enlightened researched spread some money around local villages and had 3 individuals the next morning! Not only did people rely upon its dried urine as a medication, but it turned out the squirrel formed much of the diet of a local eagle owl! Fortunately, word of its extinction reached neither the villagers nor the owls!
Good luck and please keep me posted.
Best regards, Frank Indiviglio.
Hi Frank,
I’m just wandering if this fungus is man-made or is natural?
Thanks Sion
Hi Sion,
Nice to hear from you. The bacteria occurs naturally on the skin of several amphibians;it can be removed and cultured in the lab, so as to increase production. Exciting prospect! Best, Frank
Thanks Frank,
I was unsure and is it a serious threat? I mean could it potentially wipe out all Amphibia?
Thanks Sion
Hi Sion,
Thanks for your interest. The epidemic is considered one of the most serious threats to any group of animals that has ever been documented…a god summary of what is known can be found here http://www.amphibianark.org/the-crisis/chytrid-fungus/. Please let me know if you need more info, Best, Frank