Navigation Links
Common North American frog identified as carrier of deadly amphibian disease
Date:3/14/2012

AUDIO: This is an audio recording of the distinctive "ribbit " call of the Pacific chorus frog (28 seconds long, MP3 file, WAV file available on request). This noisy frog is a potent...

Click here for more information.

Known for its distinctive "ribbit" call, the noisy Pacific chorus frog is a potent carrier of a deadly amphibian disease, according to new research published today in the journal PLoS ONE. Just how this common North American frog survives chytridiomycosis may hold clues to protect more vulnerable species from the disease.

Chytrid has wiped out more than 200 frog species across the world and poses the greatest threat to vertebrate biodiversity of any known disease.

In California's Sierra Nevada Mountains, San Francisco State University biologist Vance Vredenburg has studied the impact of chytrid since 2003. His team's latest findings suggest the disease is widespread among Pacific chorus frogs but the species rarely shows symptoms, making it a highly effective carrier.

"We found that the vast majority of Pacific chorus frogs don't die or show symptoms even with surprisingly high levels of infection," said Natalie Reeder, who conducted the research for her master's thesis at SF State. "They are able to go about life as normal, moving over land and carrying the disease to new locations."

Pacific chorus frogs (Pseudoacris regilla) are one of the most common frogs on the west coast of North America and are found along the Pacific coast from Baja California to British Columbia. These small frogs range in color from bright green to gold or brown, and are common in urban yards and parks as well as remote habitats.

Their abundance and mobility make them dangerously effective at spreading the chytrid fungus. The frogs have sticky toe-pads that help them climb and can survive longer periods out of water compared to other species.

"The Pacific chorus frog is a perfect host for chytrid, allowing the disease to leap frog to the next pond over," said Vredenburg, assistant professor of biology at San Francisco State University. "The findings help explain the pattern and speed of the chytrid epidemic in the Sierras."

Chytridiomycosis is a deadly disease caused by an aquatic fungus called Batrachochytrium dendrobatidis (Bd). Because it is a water-borne fungus, scientists assumed it would spread downstream through rivers and lakes. But in the Sierra Nevada, the epidemic moved uphill.

"Our findings explain the steady march of chytrid up the mountain," Reeder said. "These frogs can climb mountains and go places that are pretty dry."

Surveys in Sixty Lakes Basin in the Sierra Nevada revealed that between 2003 and 2010, Pacific chorus frog populations remained stable in 26 lakes and ponds and even colonized one new lake. During the same time period, a chytrid epidemic swept through the basin, causing mass die-offs among other species, such as the mountain yellow-legged frog, which was reduced to 5 percent of its historic habitat range.

Pacific chorus frogs survived the outbreak but did not escape infection. Skin swabs collected from the species in Sixty Lakes Basin in 2009 confirmed that two-thirds of the animals tested were infected with the Bd fungus.

Similarly in lab studies, 35 out of 39 frogs collected from the San Francisco Bay Area tested positive for the fungus. After four months of monitoring in the lab, 38 out of the 39 showed no symptoms of chytridiomycosis. Typical symptoms include weight loss, excessive skin shedding and a frog's inability to right itself when turned on its back.

"Pacific chorus frogs are not completely immune to the disease but under the right circumstances they seem to be able to cope with high levels of infection," Vredenburg said. Lab tests revealed the species tend to carry greater loads of the fungus, making it more infectious compared to other documented carriers of chytrid, such as the African clawed frog and the American bullfrog.

The study also identified an important survival mechanism that could help Pacific chorus frogs survive infection. The typical pattern of infection with chytrid involves the fungus attacking frogs' skin, causing it to become up to 40 times thicker than usual -- a deadly change given that frogs use their skin to absorb water and vital salts, such sodium and potassium. But in highly infected Pacific chorus frogs, the researchers found a mosaic of infected, thicker skin adjacent to normal skin.

"It looks like this patchy infection allows the healthy skin to continue functioning normally," Vredenburg said.

It is still unknown what keeps the infection from covering a frog's entire skin, but Vredenburg's next step is to investigate whether beneficial skin bacteria plays a role. If that is the case, the findings could inform the development of treatments to help more endangered amphibian species survive this global fungal epidemic.


'/>"/>

Contact: Elaine Bible
ebible@sfsu.edu
415-405-3606
San Francisco State University
Source:Eurekalert  

Related biology news :

1. Commonly used herbicides seen as threat to endangered butterflies
2. Researchers find safer way to use common but potentially dangerous medication
3. Researchers identify novel pathway responsible for infection of a common STD pathogen
4. New research to help eliminate most common food poisoning bug
5. CU School of Medicine researchers look at effects of 2 common sweeteners on the body
6. Researchers develop gene therapy that could correct a common form of blindness
7. Sweeping genetic analysis of rare disease yields common mechanism of hypertension
8. Research team discovers genes and disease mechanisms behind a common form of muscular dystrophy
9. Creative Commons non-commercial licenses impede the re-use of biodiversity information
10. Cell surface mutation protects against common type of malaria
11. Bacteria responsible for common infections may protect themselves by stealing immune molecules
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Common North American frog identified as carrier of deadly amphibian disease
(Date:2/8/2017)...  Aware, Inc. (NASDAQ: AWRE ), a leading ... for its quarter and year ended December 31, 2016. ... $3.9 million compared to $6.9 million in the same quarter ... was $0.6 million compared to $2.6 million in the fourth ... 2016 was $0.5 million, or $0.02 per diluted share, which ...
(Date:2/7/2017)...   MedNet Solutions , an innovative SaaS-based eClinical ... research, is pleased to announce that the latest release ... flexible and award winning eClinical solution, is now available ... is a proven Software-as-a-Service (SaaS) clinical research technology platform ... also delivers an entire suite of eClinical tools to ...
(Date:2/3/2017)... , Feb. 3, 2017  Texas Biomedical Research Institute ... Larry Schlesinger as the Institute,s new President ... Biomed effective May 31, 2017. He is currently the Chair ... of the Center for Microbial Interface Biology at Ohio State ... as the new President and CEO of Texas Biomed," said ...
Breaking Biology News(10 mins):
(Date:2/21/2017)... , ... February 21, 2017 , ... ... organizations to build connected digital health applications, announced a partnership with Redox, a ... to seamlessly connect to many clinical systems while keeping data secure in the ...
(Date:2/21/2017)... ... February 21, 2017 , ... Genedata, a leading provider ... announced the establishment of Genedata Limited as a new subsidiary in the United ... in life science informatics. Creating the UK subsidiary reinforces Genedata’s commitment to collaborate ...
(Date:2/21/2017)... ... February 21, 2017 , ... The medical potential of stem cells is both ... of medicine, due to their differentiating characteristics. Stem cells are unique as the have ... be induced to become tissue or organic-specific cells with special functions. , Stem ...
(Date:2/21/2017)... ... February 21, 2017 , ... ... manufacturing facility at its headquarters laboratory in Poway, California. Based upon 12 ... of both in-house personnel and consultants, VetStem constructed and validated a state-of-the-art GMP ...
Breaking Biology Technology: