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Batrachochytrium salamandrivorans: Determining the Risk to North America


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Delivered at the Annual Meeting of the Southeastern Association of Fish and Wildlife Agencies by Matt Gray, Debra Miller, and Bill Sutton

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Batrachochytrium salamandrivorans: Determining the Risk to North America

  1. 1. Batrachochytrium salamandrivorans: Determining the Risk to North America 1 UTIA Center for Wildlife Health 2 TSU Department of Agricultural & Environmental Sciences Matthew J. Gray1 , Debra L. Miller1 , & William B. Sutton2 F. Pasmans, Ghent Univ. Robertville, Belgium
  2. 2. Acknowledgements Priya Nanjappa, AFWA J. J. Apodaca, Warren Wilson College Michelle Koo, UC-Berkeley Vance Vredenburg, San Francisco State University Karen Lips, University of Maryland Allan Pessier, San Diego Zoo An Martel, Ghent University Frank Pasmans, Ghent University
  3. 3. *2010: 96% wild mortality in Netherlands *2013 & 2014: wild mortality in Belgium *2015: UK (trade) and Germany (captivity) *Present in: *wild salamanders in Asia (Vietnam, Thailand, Japan) *museum records in Asia >150 yrs *possible Asia origin Martel et al. 2013, PNAS; Martel et al. 2014. Science; Cunningham et al. 2015. Veterinary Record; Sabino-Pinto et al. 2015. Amphibia-Reptilia The Pathogen Frank Pasmans Unknown to occur in North America Salamandra salamandra
  4. 4. Bsal Pathology -- DEB Multifocal erosions and deep ulcerations of the skin throughout the body Death generally occurs in under 2 weeks after a short episode of anorexia, apathy, and ataxia (Credit Frank Pasmans/Ghent University) Blooi, M. et al. 2015
  5. 5. A lesion viewed under the microscope… Dead cells (orange arrows) Bsal thalli (black arrows) epidermis Keratin Photomicrograph courtesy Allan Pessier, UC Davis
  6. 6. How does Bsal chytridiomycosis differ from Bd chytridiomycosis? Bd Bsal Near full-thickness necrosis (loss) of epidermis with numerous chytrid thalli (mostly empty) that frequently show internal septa (colonial thalli; arrows). Orange circle shows an intact cell (keratinocyte) with 2 chytrid thalli in its cytoplasm. Thickening of the skin (epidermis) and outer keratin layer with numerous thalli in superficial keratinocytes (note various stages; some with zoospores, green arrows; some empty, orange arrows). The cells (keratinocytes) within the epidermis are still distinct and somewhat in layers. Photomicrographs courtesy Allan Pessier, UC Davis epidermis
  7. 7. The Perils Martel et al. 2014. Science al Salamander-specific pathogen? 10 Anurans 24 Salamanders Infected no death Infected some death Infected 100%
  8. 8. * 100,000+ annual salamander imports to US * primarily Asian newt species * North American species are susceptible The Perils Jason Quinn Gray et al. (in press). PLOS Pathogens $1,000,000 per year Pachytriton 95%
  9. 9. Jenkins et al. 2013. PNAS. The Perils
  10. 10. Amphibian richness, 270 spp, 190 salamanders The Perils
  11. 11. The Perils Many SE States!
  12. 12. Thermal preference
  13. 13. Risk Model Final Risk Assessment Model - Relative Risk = SpRich * Log ClimSuit Bsal
  14. 14. Appalachia and Southeast US • Highest taxonomic diversity • 7/10 Families – Plethodontidae – Salamandridae • Up to 29 co-occurring species • Many endemic species • Includes Eastern Newt range Photos by Henk Wallays and Todd Pierson
  15. 15. West Coast of the US • Highest Bsal habitat suitability • 5/10 Families – Salamandridae and Plethodontidae • Up to 12 co-occurring species • Includes Rough-skinned newt range Photos by Tiffany Yap, Harry Greene, Todd Pierson, and Sam Murray 1 5
  16. 16. Central Highlands of Mexico • Sierra Madre Occidental, Sierra Madre Oriental, and Trans-Mexican Volcanic Belt • Hotspots of tropical salamander diversity • High endemism; high beta diversity • Many are threatened or endangered Photos by Abel Batista, Todd Pierson, Sean Rovito 6
  17. 17. Which NA Ports Pose Greatest Threats for Bsal Introduction? Identification of At-Risk Ports: •Shipments 2010 – 2014 •Native ranges in Asia •Shipments through Asia •99% shipments from Asia •98% of shipments Asian species •91% of shipments contained C. pyrrhogaster, C. cyanurus, & P. deloustali
  18. 18. North American Species Tested Clinical Disease Subclinical Disease Not infected: Martel et al. (2014)
  19. 19. Threat to southern Appalachian species • Threat- moderate • 1 of 3 Hynobs “tolerant” to Bsal • Habitat of S. keyserlingii- terrestrial but breed in permanent pools • Cryptobranchids unknown.
  20. 20. Salamandrids • Threat- high • Nearly all species died from infection at a low dose • Large populations and widespread- might serve as amplification host • Terrestrial and aquatic post-metamorphic forms & high dispersal give this family the ability to rapidly spread Bsal
  21. 21. Salamandridae: North America – 7 Species
  22. 22. Dusky and climbing salamanders • Threat- Possibly high • Bsal was lethal in Hydromantes, which is very similar ecologically to Aneides • Desmogs: many regionally endemic; none tested.
  23. 23. Woodland Plethodontids • Only one species tested: Plethodon glutinosus was not susceptible • Very diverse; regionally endemic
  24. 24. Ambystomatids • Threat- possibly low • 2 species tested; not susceptible
  25. 25. Sirenidae • Threat - moderate • One species tested; “tolerant” of infection
  26. 26. Waterdogs and amphiumas • None tested
  27. 27. Splerpines • Gyrinophilus was not susceptible • Eurycea & Pseudotriton not tested • Hemidactylium not tested
  28. 28. Research Directions 1) Host range: • Susceptibility Trials • SE Unique lineages • Cryptobranchids • Necturus • Desmognathus • Eurycea • Aneides • Amphiuma • Plethodon (limited) • Ambystoma (limited) • NW Unique lineages • Dicamptodon • Rhyacotriton • Taricha (limited) Dose Dependent (LD 50 Estimate) 5 x 103-6 Zoospores Dec/Jan = P. shermani, A. opacum, L. chiricahuensis, H. chrysoscelis, L. sylvaticus Spring/Summer = Chryptobranchus, Necturus, A. laterale, L. clamitans, Pachytriton
  29. 29. Research Directions 2. Surveillance: • Wild populations (new vs. preserved) • Captive populations Locations? Species?
  30. 30. Organizational Structure TAC Co-Chairs: Dede Olson (USFS), Jenn Ballard (USFWS) Southern Appalachian Task Force: Caleb Hickman (EBCN)
  31. 31. Questions?? Photo: A. Balseiro