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Chytridiomycosis (Batrachochytrium dendrobatidis)

Carson Lillard WFS 433 Amphibian Ecology and Conservation Department of Forestry, Wildlife, and Fisheries

University of Tennessee

“The largest infectious disease threat to biodiversity” (Kilpatrick et al. 2010)

What is it? ´  Fungus that causes skin disease

´  Causes thickening of the skin, and infected toads and frogs tend to shed skin frequently (Northern Rocky Mountain Science Center)

´  Thickening of the skin may impair gas exchange and affect the animal's ability to absorb water (Northern Rocky Mountain Science Center)

´  Chytrid fungus infects keratinized mouthparts of tadpoles and keratinized skin, and has caused significant die-off's (Nichols et al. 2001)

´  Lunged- Abnormal electrolyte levels cause the heart to stop beating and the death of the animal (Voyles et al. 2009)

´  Lungless-Suffocation

World of Frogs. http://theworldofrogs.weebly.com/chytrid-fungus.html

Where is it? ´  Has been detected on at least 350 species of amphibians

worldwide (Fisher et al. 2009)

´  Detected on every continent that has amphibians (Fisher et al. 2009)

How did it get here? ´  Africa is the origin of the amphibian chytrid

´  International trade of X. laevis (African clawed frog) began in the mid-1930s (Weldon, Ché et al. 2004.)

Horvath, J. et al 2014.

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Importance ´  Bd has been called “the worst infectious disease ever recorded among

vertebrates” in terms of the number of species impacted, and it’s tendency to drive them to extinction (Gascon et al, 2007).

´  Rapid decline- sometimes over a few weeks (Lips et al., 2006)

´  Disproportionately eliminates species that are rare, specialized, and endemic (Smith et al., 2009)

´  “Typhoid Mary”

´  Some of these threats can be mitigated through legal and physical protection of species, but many – such as the amphibian chytrid fungus cannot. (Maryland Zoo)

Figure 3: Spatial distribution and pairwise overlap of the three main factors threatening global amphibian biodiversity, projected for the year 2080 (Hof, et al. 2011)

Outbreaks ´  Severe impacts upon amphibian populations at a number

of locations around the world, specifically in Australia (Berger et al.

1998), Central America (Lips 2006), USA (Fellers et al. 2001), South America (Young et al. 2001)

Examples ´ Panamanian golden frogs ´  listed as critically endangered

´   last recorded in the wild in 2009 (Smithsonian Science News)

´  may be extinct now in the wild (Maryland Zoo)

´ Golden toad ´  Last seen in the wild in 1989

(Columbia University, Earth Institute)

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Video

´  http://www.nps.gov/media/video/view.htm?id=DCF98D8A-9961-727F-50316F2A2037B0E3

´  Sierra Nevada Yellow Legged Frog

´  Use to be most abundant vertebrate in the Sierras

´  1999 noticed populations were declining

´  Chytrid was the main culprit

´  What to do with populations that do have chytrid?

´  Start video at 5:11

Questions?

http://animal-kid.com/desert-rain-frog-size.html

References ´  Berger, L., R. Speare, P Dazsak, D.E. Green, A.A. Cunningham, C.L. Goggin, R. Slocombe, M.A. Ragan, A.D. Hyatt, K.R. McDonald, H.B. Hines, K.R. Lips, G. Marantelli and H. Parkes . 1998.

Chytridiomycosis causes amphibian mortality associated with population declines in the rain forests of Australia and Central America. Proceedings of the National Academy of Sciences of the United States of America 95: 9031-9036.

´  El Niño and a Pathogen Killed Costa Rican Toad, Study Finds. Columbia University, Earth Institute. Web. 20 Apr. 2015. http://www.ldeo.columbia.edu/news-events/el-ni%C3%B1o-and-pathogen-killed-costa-rican-toad-study-finds

´  Fellers,G.M., Green, D.E., Longcore J.E. 2001. Oral chytridiomycosis in the mountain yellow-legged frog (Rana muscosa). Copeia, Issue 4. National Wildlife Health Center.

´  Fisher, M.C.,Garner T.W, Walker S.F. 2009. Global emergence of Batrachochytrium dendrobatidis and amphibian chytridiomycosis in space, time, and host. Annu Rev Microbiol. 63:291-310.

´  Gascon C., J.P. Collins, R.D. Moore et al., editors: Amphibian Conservation Action Plan. IUCN/SSC Amphibian Specialist Group. Gland, Switzerland and Cambridge UK, 2007.

´  Global Bd Mapping Project. Olson, Dede. "Aquatic Ecology and Management." U.S. Forest Service. U.S. Forest Service. Slide 3. http://www.fs.fed.us/pnw/lwm/aem/people/olson.html

´  Hof, C., Araújo, M. B., Jetz, W., & Rahbek, C. 2011. Additive threats from pathogens, climate and land-use change for global amphibian diversity. Nature: International Weekly Journal of Science.

´  Horvath, Julie, and Heather Farrington. "Test for Fungus Safeguards Amphibians." The Charlotte Observer, Scitech. N.p., 16 Nov. 2014. Web. 20 Apr. 2015. http://www.charlotteobserver.com/news/science-technology/article9230354.htm

´  Kilpatrick, A.M., Briggs, C.J., Daszak, P. 2010. The ecology and impact of chytridiomycosis: an emerging disease of amphibians. Trends in Ecology and Evolution, Volume 25, Issue 2, Pages 109–118.

´  Lips, K.R., F. Brem, R. Brenes, J.D. Reeve, R.A. Alford, J. Voyles, C. Carey, L. Livo, A.P. Pessier, and J.P. Collins. 2006. Emerging infectious disease and the loss of biodiversity in a Neotropical amphibian community. Proceedings of the National Academy of Sciences of the United States of America 103:3165-3170.

´  Maryland Zoo. Panamanian golden frog Information. http://www.marylandzoo.org/animals-conservation/amphibians/panamanian-golden-frog/

´  Nichols, D. K., Lamirande, E. W., Pessier, A. P., and Longcore, J. E. 2001. Experimental transmission of cutaneous chytridiomycosis in dendrobatid frogs. Journal of Wildlife Diseases 37: 1-11.

´  Northern Rocky Mountain Science Center. "Amphibian Diseases." USGS. http://nrmsc.usgs.gov/rarmi/amphibdisease

´  Rachowicz, Lara. "Overview of Amphibian Diseases." Amphibiaweb. N.p., 2008. Web. http://amphibiaweb.org/declines/diseases.html

´  Save The Frogs. Photograph. http://www.google.com/imgres?imgurl=http://www.savethefrogs.com/threats/chytrid/images/Swabbing-Litoria-wilcoxii.JPG&imgrefurl=http://www.savethefrogs.com/threats/chytrid/&h=330&w=440&tbnid=HaYrBq4Hrns33M:&zoom=1&docid=P385gdPuvNxozM&ei=qw80VfwGhp-DBJDbgOAF&tbm=isch&ved=0CC4QMygRMBE

´  Smith, K.G., K.R. Lips, and J.M. Chase. 2009 Selecting for extinction: nonrandom disease-associated extinction homogenizes amphibian biotas. Ecology Letters 12:1069-1078

´  Smithsonian Science News. “Success: Panama’s golden frog bred in captivity”. http://smithsonianscience.org/2013/08/panamas-golden-frog-bred-in-captivity-for-first-time/

´  Weldon, Ché et al. “Origin of the Amphibian Chytrid Fungus.” Emerging Infectious Diseases 10.12 (2004): 2100–2105. PMC. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3323396/

´  Voyles, J., S. Young, L. Berger, C. Campbell, W.F. Voyles, A. Dinudom, D. Cook, R. Webb, R.A. Alford, L.F. Skerratt, and R. Speare. 2009. Pathogenesis of chytridiomycosis, a cause of catastrophic amphibian declines. Science 326:582-585.

´  World of Frogs. Photograph, Slide 2. http://theworldofrogs.weebly.com/chytrid-fungus.html

´  Young, S., Berger, L., Speare, R. Amphibian chytridiomycosis: strategies for captive management and conservation . Amphibian Disease Ecology Group, School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Townsville Qld 4811, Australia