Fatal frog fungal disease figured out - Electrolyte imbalance stops amphibians' hearts.
Nature News ^ | 22 October 2009 | Emma Marris
Frogs are suffering from a fatal fungal infection.Vance T. Vredenburg/SFSU
A fungal infection that is killing amphibians around the world acts by disrupting the flow of electrolytes across their skin, ultimately causing heart failure. The discovery is helping to raise hopes that a treatment for the infection could one day be given to amphibians in the wild.
Batrachochytrium dendrobatidis, a kind of chytrid fungus that causes the skin disease chytridiomycosis in amphibians, was likely spread around the world by the South African clawed frog (Xenopus laevis) in the 1930s and 1940s, when the frog was widely used as a pregnancy test. A pregnant woman's urine, injected under the frog's skin, would contain sufficient hormones to make the animal ovulate.
But although the South African clawed frog seems to have immunity to the disease, many other amphibians are not so lucky. According to one study led by chytrid expert Karen Lips of the University of Maryland in College Park, chytridiomycosis can kill 80% of amphibians in one year in an area with cool, moist conditions.1 Until now, no one was sure exactly how the fungus killed its victim; some researchers thought that it might secrete a poison.
Jamie Voyles, a disease ecologist at James Cook University in Townsville, Queensland, Australia, and colleagues exposed Australian green tree frogs (Litoria caerulea) to the fungus, and have now worked out its deadly mode of attack.
Voyles and colleagues monitored the progression of the infection, took blood and urine samples and measured electrolyte flow across skin samples. They found that levels of two ions — potassium and sodium — were greatly reduced in infected frogs, and that the ability to move these ions back and forth across the animals' skin had been greatly impaired.
"Frog skin is really unique because it is permeable to water but it must maintain proper concentrations of these [electrolyte] ions," says Voyles. In infected frogs, "the electrolyte balance is all out of whack".
The low potassium levels, in particular, were probably responsible for a breakdown of the electrical regulation of the heart, and the frogs ultimately died because their hearts stopped. The work is reported in Science2.
The team found that an electrolyte-rich solution, similar to sports drinks but more concentrated, delayed death in infected frogs. But it couldn't cure them. "Because the skin is damaged, we can't really keep them from dying unless we fix the problem in the skin," says Voyles.
Although captive frogs can be bathed in an antifungal medicine to rid them of their infection, there is no easy way to treat the hundreds of species of wild amphibians at risk of being wiped out by the fungus.
Voyles's work is just one piece of research that might someday lead to a treatment that could be deployed in the wild. Geneticist Erica Rosenblum of the University of Idaho in Moscow is looking at gene expression in both the fungus and the host to determine what makes the fungus so lethal — and why amphibian immune systems don't seem to be aware of the infection.3 "Jamie has found that their osmotic regulation is all screwed up, they are essentially having heart attacks," she says. "Mine is an earlier question: why don't they have an immune response?"
One possible treatment is being pursued by Reid Harris, a microbial ecologist at James Madison University in Harrisonburg, Virginia. He has found that at least some species of amphibians have beneficial bacteria on their skin that produce a protective antifungal agent.4 He is looking into the possibility of adding more of these bacteria to the soil in ecosystems where vulnerable amphibians live, to boost their natural defences. "People are already doing this in their gardens and larger-scale agricultural applications as well," he says.
Harris would first like to try the technique on populations of frogs in captivity — so-called survival assurance colonies held in zoos and other institutions awaiting the day when they can be safely returned to the wild.
Despite all these advances, Lips says that she has seen too many frog populations destroyed by the fungus to retain her optimism about saving what is left. "I don't know that there is enough money going to the right labs quickly enough to make a difference," she says. "More governments and NGOs need to step up. I mean, we are losing half the amphibians on the planet. And throwing amphibians into zoos is a short-term solution. It doesn't solve any problems."
1. Lips, K. R., et al. Proc. Natl. Acad. Sci. USA 103, 3165-3170 2006 | Article | PubMed | ChemPort |
2. Voyles, J. et al. Science 326, 582-585 (2009).
3. Rosenblum, E. B. et al. PLoS ONE 4, e6494 (2009).
4. Harris, R. N., Lauer, A., Simon, M. A., Banning, J. L. & Alford, R. A. Dis. Aquat. Organisms 83, 11-16 (2009).
Courtesy Nature News
site for those that want to really get a lot more:
- amphibian chytridiomycosis - yahoo
Science 23 October 2009:
Vol. 326. no. 5952, pp. 582 - 585
Pathogenesis of Chytridiomycosis, a Cause of Catastrophic Amphibian Declines
Jamie Voyles,1,* Sam Young,1 Lee Berger,1 Craig Campbell,2
Wyatt F. Voyles,3 Anuwat Dinudom,2 David Cook,2 Rebecca Webb,1
Ross A. Alford,4 Lee F. Skerratt,1 Rick Speare,1
The pathogen Batrachochytrium dendrobatidis (Bd), which causes the skin disease chytridiomycosis, is one of the few highly virulent fungi in vertebrates and has been implicated in worldwide amphibian declines. However, the mechanism by which Bd causes death has not been determined. We show that Bd infection is associated with pathophysiological changes that lead to mortality in green tree frogs (Litoria caerulea). In diseased individuals, electrolyte transport across the epidermis was inhibited by >50%, plasma sodium and potassium concentrations were respectively reduced by ~20% and ~50%, and asystolic cardiac arrest resulted in death. Because the skin is critical in maintaining amphibian homeostasis, disruption to cutaneous function may be the mechanism by which Bd produces morbidity and mortality across a wide range of phylogenetically distant amphibian
Full text at sciencemag.org
1. School of Public Health, Tropical Medicine and Rehabilitation Sciences, Amphibian Disease Ecology Group, James Cook University, Townsville, QLD 4811, Australia.
2. Discipline of Physiology, Bosch Institute, Faculty of Medicine, University of Sydney, Sydney, NSW 2006, Australia.
3. School of Medicine, Division of Cardiology, University of New Mexico, Albuquerque, NM 87131, USA.
4. School of Marine and Tropical Biology, Amphibian Disease Ecology Group, James Cook University, Townsville, QLD 4811, Australia.
Help fight Amphibian Chytrid (Chytridiomycosis) Fungus
one of the main threats to many amphibians!
Over one-third of the world's amphibian
species are considered threatened or endangered. For decades,
scientists have studied the disappearance of amphibians and have
even discovered some of the possible causes including global climate
change, habitat loss and pollution. Recently, an emerging infectious
disease known as the Amphibian Chytrid Fungus has been shown to wipe
out massive numbers of amphibians from pristine natural locations in
many places around the world. This disease is currently unstoppable
in the wild, but treatable in captivity
Learn more at the following links:
Learn how to identify and if found
please notify Tucsonrana or Dr Phil Rosen at University of Arizona immediately!!
Think Globally Act Locally
Field Trips Page!
Idea to show submitted images of frogs
or toads in their habitats. Any habitat, any region, any country.
Frog and Toad cams included.
Using a global mapping service you
will be able to go to the exact coordinates for each set of images
when GPS data is provided. Otherwise you will go to general area.
Would like to see this as an
interactive page. If anyone has any ideas, please email. firstname.lastname@example.org
Requested images and information:
- Image - Overall location
- Image - Specific location
- Images - Subject, as many as you
- Info - Direction you are looking in
- Info - As much as you want to
provide about general or specific habitat you found submitted
- GPS coordinates would be ideal
Until then the Field Trips Page will
be the scrap book for pictures people have sent in. Thank
JUNE 04 2007
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service - Endangered and Threatened Wildlife and Plants;
AGENCY: U.S. Fish and Wildlife Service, Interior.
ACTION: Notice of availability; final recovery plan for Chiricahua leopard frog.
SUMMARY: We, the U.S. Fish and Wildlife Service (Service) announce the
availability of a final recovery plan for the Chiricahua leopard frog
(Rana chiricahuensis). The species occurs in central and southeastern
Arizona, west-central and southwestern New Mexico, and the sky islands
and Sierra Madre Occidental of northeaster Sonora and northwestern
Chihuahua, Mexico. The Chiricahua Leopard Frog Recovery Plan presents
information on the species and its habitat, including delisting criteria and
recovery actions to conserve the species
Click to see full text - [Federal
Register: June 4, 2007 (Volume 72, Number 106)]
For those that did not receive a
copy of the hand-out from Kathryn Mauz's Presentation at the August
Meeting of The Tucson Watergardeners Club about the history of
aquatic and riparian plants found in the Tucson Basin-
Here it is: you will need Adobe
Reptiles, and their habitats at Sabino Canyon"
of Availability of the Draft Recovery Plan for the
Chiricahua Leopard Frog
Click below to see the bad
or below to see the ugly
courtesy of Pima County's Sonoran
Desert Conservation Plan
Please be responsible
Do Not Release unwanted plants or animals into the wild -
If you have aquatic plants or
animals you have to get rid of please contact the webmaster of this
website or a member of The Tucson Watergardeners
Click on these guys-
to see the natives of Tucson
awarding grants to U of A
Extension Farm and Schumacher Grade School for the funding of the
building of educational water features. Click
here to see the article
to Laguna Elementary School staff and especially students! They
are Grant recipients that with the help of many in the community
have a new educational, relaxation pond.
here to see past programs
check out the pages below:
Study has been completed-
Thank you all!
Do you want to do
something to help declining amphibians?
the mapping of Tucson's frogs and
toads is being compiled
Results of a three year study.
Tucson's Lowland leopard frogs are
coming back! Study shows that our Lowland leopard frog are making a
comeback - thank you to those involved.
continue to compile data after this this study.
Think globally and act locally.
Tucsonrana will continue to work with U of A and national researchers
in gathering information on frog and toad populations in the city of Tucson and surrounding areas. We need you to
listen for frog and toad choruses in the vicinity of your home. If
you can document any sounds and estimate numbers please email with
any information you can gather, Recordings with images if possible.
You can listen to voices on the
**Please listen for any frog or toad song -
generally from February through September**
Looking to find the locations of the toads
and frogs of the Tucson Basin by their song.
If you live close to any
riparian area like streams, washes, cienagas or man made ponds
you could well hear or see what we are interested in.
Tucsonrana or Dr Rosen with any information you have.
Leopard Frog breeding
generally takes place February through March when night
when night temperatures are over 10C/50F.
Most of our toads
will be heard during monsoon. UofA extension farm at Campbell
and Roger is a great place to hear Couchi and Great
If you want to
get more information please email this website or contact
Phil Rosen at
319-0470, Dennis Caldwell at 624-0198 or Jay Evenson at
Read the post from Phil Rosen-
a list of the wanted with images and sounds: (A page in
progress, looking for images
and recordings from anyone in the Tucson area. Please send to; email@example.com
Print or download- Category
and species sheet- .doc
Print or download- Tucson
Area Toad and Frog Larval Period Data -.doc
Print or download- DATA
SHEET DL form-.doc
River/Dodge to Ina Route Reports, je
aug 09 2004
The Monsoon is not being kind to us this year. Except for the
southeast and the north side of the Catalina's bringing water
to the Pantano and Canada del Oro we are very dry. I haven't seen
the Rillito at Dodge or Campbell running side to side yet. We still
have a some time for central and west to get some wet. This is also
a good time to plan out sites that you would want to go for the
Yet another disappointing year for our wet season. The extended
drought conditions are starting to been seen with more clarity now.
Trees near the rivers are really starting to show stress. Even the
cacti and "drought tolerant" plants are taking a beating.
I heard very little activity on the normally noisy route. Let's hope
for a better winter/spring rainfall.
Reports from Mountain and Roger
Well that didn't help much. 2 in if
we were lucky in the Roger/Mountain area for the winter. Hearing of
more incidents of WILDLIFE coming into ponds.
I would like to hear from any or
all of you that have had or are having close encounters with said
Wildlife. Had a raccoon attack in my pond this year, had to
get over 5 ft walls to get in. Cats get in so I know there is no
problem for one of the midnight bandits. Heard from CH that
they had one drinking out of their dogs water dish. Saw him after
the backyard motion light came on.
So please email with creature,
date, time, and location. Would be interesting to see if there are
any patterns here.
UofA extension farm and River Road
With the road changes to River Road
and addition of the Alvernon Way bridge we have lost a lot of native
wildlife habitat. Who knows what these will mean. The area around
the bridge were usually a high count area for couchi noted during
the field study. What was found during the 2008 monsoon was
that the Great Plains Toad were much more prevalent. If this
is due to changes in habitat or just a natural cycle will have to be
studied and documented.
Couchi seemed to be less prevalent
While Great Plains more this season over all. My thoughts are that
it is part of a natural cycle. Let's see what happens during the 09 monsoon.
Safe Harbor Agreement for Topminnow and Pupfish can
be seen at: (you will need adobe acrobat to view it online) http://www.setonresourcecenter.com/Register/2004/Mar/25/15362A.pdf
Copy of agreement can be obtained by writing to
Regional Director US Fish and Wildlife Service
PO Box 1306 room 4102
Albuquerque, NM 87103
Tucson sub-office Arizona Ecological Services Field Office
201 North Bonita Ave suite 141
Tucson, AZ 85745
520 670 6144 ext 236
Please refer to PDF article for submission of comments addresses.
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to me -2
watching and listening
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