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By Heather Paul
By Leein HisroomBy Renato Gaiga
By Brian Gratwicke
By Brian Gratwick
By Andreas Kay
The frog-killing fungus in
Nanaimo, BCAn undergraduate research project by Patrick
Reid
Part 1 WORLDWIDEPart 2 The local AREA
Part 3 Implications
The frog-killing fungus
PART 1 WORLDWIDE
By Geoff Gallice
AMPHIBIAN STATUS Recent worldwide declines 1/3 of all identified species are
at risk of extinction
(Stuart et al. 2004)
Amphibians are the most threatened vertebrate group.
SAD FROG
By Elvir B
Amphibian
Declines
Habitat Loss
Over Exploitatio
n
Invasive Species Pollution
Wildlife Diseases
Climate Change
Declines in pristine mountain areas.
How is this possible?
Chytrid Fungus (Batrachochytrium dendrobatidis)
Potentially lethal skin infection on amphibians (Berger
et al. 1998)
Caused decline or extinction of 200 amphibian species worldwide (Skerrat et al. 2007)
Amphibia.web
The emergence of Bd may represent the greatest pathogen-associated biodiversity loss in recorded history (Skerrat et al. 2007)
Why the recent increase
in Bd-associated mortalities?
BatrcachochytriumdendrobatidisBatrachochytrium
dendrobatidis
Strain level(variants)
Species level
KIll (no/yes)
Multiple variants: some kill some don't(Berger et al. 2005)
Spread of Bd
Past
Present
Global Spread of pathogenic variants of Bd
(Example: not actual locations)
Strain A
Strain BStrain C
Pathogenic strains may have been spread through the amphibian trade
American bullfrogs are resistant to Bd and me be acting as global carriers (Daszak et
al. 2004; Schloegel et al. 2012)
Bullfrogs as disease carriers
By Goly Shev
By Jonathan E. Kolby
Amphibians for worldwide shipment Bullfrogs being sold in Shanghai
Part 2 The local AREA
By Ken Walker
Local species infected with BD
American bullfrog(Lithobates
catesbeianus)
Western Toad (Anaxyrus boreas)
Photo courtesy of Bill Pennell Photo courtesy of Elke Wind
Western toads Blue-listed in BC (at risk of becoming
threatened) Bd-caused declines of Western Toads
in the United States raises concern (Muths et al. 2003)
Photo courtesy of Elke Wind
American bullfrogs Invasive species on Vancouver Island
May have brought foreign strains to local area
May spread infections among local toads
research objective
Use strain data to asses
bullfrogs role in the local spread and arrival of Bd
Find out what strain (variant) is present on local
toads and bullfrogs
Swabbing for presence of Bd
Analysis of Skin Swabs
Extract
Detect
Identify Strain
Part 3 Implications
The strain detected (CW 34) is likely pathogenic to amphibians, heightening the risk for toad mortalities locally.
How did it get to Nanaimo?
bullfrogs Role in the spread of Bd
Possibility
Evidence
resultArrived to
Nanaimo on bullfrogs
Transferred between bullfrogs and toads
CW 34 on bullfrogs in the amphibian trade
and locally
CW 34 present on both bullfrogs and toads in Nanaimo
Does not refute
Support
Take home messages Amphibians are declining, with Bd
acting as a strong contributor Toads and bullfrogs in the local area
are infected with the Bd The presence of a pathogenic strain
of Bd on local toads heightens the importance of monitoring toad populations
By Heather Paul
By Leein HisroomBy Renato Gaiga
By Brian Gratwicke
By Brian Gratwick
By Andreas KayBy Heather Paul
By Leein HisroomBy Renato Gaiga
By Brian Gratwicke
Acknowledgment
I would like to thank Hitomi Kimura for helping me with the research and my supervisors Dr. Eric Demers for guiding me through the project and
Dr. Catherine Thomson for her molecular knowledge. I am grateful
for the help of Wendy Simms and Dr. Timothy Goater in collecting bullfrog
samples.samples.
ReferencesBerger, L., G. Marantelli, L.F. Skerratt and R. Speare. 2005b. Virulence of the amphibian chytrid
fungus Batrachochytrium dendrobatidis varies with the strain. Disease of Aquatic Organisms 68:47-50.
Berger, L., R. Speare, P. Daszak, D.E. Green, A.A. Cunningham, C.L. Goggin, R. Slocombeh, M.A. Ragani, A.D. Hyatt, K.R. MCDonald, H.B. Hinesk, K.R. Lips, G. Marantellim and H. Paresb. 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 USA 95:9031-9036.
Daszak, P., A. Strieby, A.A. Cunningham, J.E. Longcore, C.C. Brown and D. Porter. 2004 Experimental evidence that the bullfrog (Rana catesbeiana) is a potential carrier of chytridiomycosis, an emerging fungal disease of amphibians. Herpetol. J. 14:201-207.
Muths, E, P.S. Corn, A.P. Pessier, and D.E Green. 2003. Evidence for disease-related amphibian decline in Colorado. Biological Conservation 110:357-365.
Schloegel, L.M., L.F. Toledo, J.E. Longcore, S.E. Greenspan, C.A. Vieira, M. Lee, S. Zhao, C. Wangen, C.M. Ferreira, M.R. Hipolito, A.J. Davies, C.A. Cuomo, P. Daszak and T.Y. James. 2012. Novel, panzootic and hybrid genotypes of amphibian chytridiomycosis associated with the bullfrog trade. Molecular Ecology 21:5162–5177.
Skerratt, L.F., L. Berger, R. Speare, S. Cashins, K.R. McDonald, A.D. Phillott, H.B. Hines and N. Kenyon. 2007. Spread of chytridiomycosis has caused the rapid global decline and extinction of frogs. EcoHealth 4 :125-134.
Stuart, S.N., M. Hoffmann, J.S. Chanson, N.A. Cox, R.J. Berridge, P. Ramani and B.E. Young. 2008. Threatened Amphibians of the World. Lynx Edicions, Barcelona, Spain.