Transmission of ranavirus between
ectothermic vertebrate hosts
Roberto Brenes1*, Matthew Gray1, Debra Miller1,2,
Rebecca. ...
What is killing the frogs?
• Emerging infectious
diseases (Daszak et al.
2003, Hayes et al. 2010)
• Batrachochytrium
dendr...
Ranavirus Hosts
Poikilothermic Hosts
• Turtles (Johnson et al. 2008, Allender
et al. 2011)
• Snakes (Hyatt et al. 2002)
• ...
How Does Ranavirus Persist?
• Environmental persistence
(Nazir et al. 2012)
• Post-metamorphic stages
(Brunner et al. 2004...
Community Level Transmission
Fish
Reptile
Can ranavirus move among host species?
Sympatric Ectothermic Vertebrate Species
...
Objective
• Test whether a FV3-like
ranavirus could be
transmitted between
ectothermic vertebrate
hosts
Three Suitable Hosts
0
10
20
30
40
50
60
70
80
90
100
Cope's Gray tree frog Red-eared slider Mosquito fish
Mortality(%)
85...
Treatments
1. Exposed turtle and unexposed
tadpole
2. Exposed tadpole and unexposed
turtle
3. Exposed fish and unexposed
t...
Experiment
• Direct exposure
– Exposed to 103 PFU/mL
– 3 days
• 12-L containers divided in
half by a 2000 µm plastic
mesh
...
Infection Results
• Turtles infected
amphibians
• Amphibians infected
turtles
• Fish infected Amphibians
• Amphibians did ...
Mortality Results
• Not all species caused
mortality
• Turtles caused mortality
in amphibians
• Amphibians did not
cause m...
Turtle and Fish Results
• All classes tested can
transmit the virus
• Turtles infected tadpoles
– 50% mortality
• Fish inf...
Amphibian Results
• Indirect mortality only in
amphibians
• Amphibians did not cause
fish or turtle mortality
• High indir...
New Findings
• Previous studies
– Fish susceptible to amphibian ranavirus (Jensen et al. 2011, Moody
and Owens 1994)
– Tur...
Conservation Implications
• Interclass transmission can occur among ectothermic
hosts
• Reptiles and fish can present asym...
Acknowledgments
• UT Institute of Agriculture
– UT AgResearch Grant
– UT College of Veterinary Medicine
– Access and Diver...
Questions??
Contact:
rbrenes@utk.edu
mgray11@utk.edu
dmille42@utk.edu
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Transmission of ranavirus between ectothermic vertebrate hosts

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2013 International Symposium on Ranaviruses
by Roberto Brenes

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  • ----- Meeting Notes (3/4/13 15:48) -----bold dont use naive can ranavirus can be transmitted between to one ecto to the next
  • Transmission of ranavirus between ectothermic vertebrate hosts

    1. 1. Transmission of ranavirus between ectothermic vertebrate hosts Roberto Brenes1*, Matthew Gray1, Debra Miller1,2, Rebecca. P. Wilkes2, and Thomas. B. Waltzek3 1Center for Wildlife Health and 2College of Veterinary Medicine, University of Tennessee 3College of Veterinary Medicine, University of Florida
    2. 2. What is killing the frogs? • Emerging infectious diseases (Daszak et al. 2003, Hayes et al. 2010) • Batrachochytrium dendrobatidis (Bd): Tropics • Ranaviruses: North America and Europe (Lips et al. 2005, Lips et al. 2006, Kilpatrick et al. 2010) (Duffus et al. 2008, Gray et al. 2009, Teacher et al. 2010)
    3. 3. Ranavirus Hosts Poikilothermic Hosts • Turtles (Johnson et al. 2008, Allender et al. 2011) • Snakes (Hyatt et al. 2002) • Salamanders (Jancovich et al. 2003, Geng et al. 2010) • Frogs (Green et al. 2002, Miller et al. 2007). • Fish (Chinchar et al. 2001, Gobbo et al. 2010, Jensen et al. 2011) Most Reported Die-offs
    4. 4. How Does Ranavirus Persist? • Environmental persistence (Nazir et al. 2012) • Post-metamorphic stages (Brunner et al. 2004) • Ectothermic vertebrates (Jancovich et al. 2011, Grayfer et al. 2012) – Reservoirs
    5. 5. Community Level Transmission Fish Reptile Can ranavirus move among host species? Sympatric Ectothermic Vertebrate Species Pathogen Amphibian
    6. 6. Objective • Test whether a FV3-like ranavirus could be transmitted between ectothermic vertebrate hosts
    7. 7. Three Suitable Hosts 0 10 20 30 40 50 60 70 80 90 100 Cope's Gray tree frog Red-eared slider Mosquito fish Mortality(%) 85% mortality Hoverman et al. (2011) 40% mortality Waltzek et al. (unpub.data) 10% mortality Brenes et al. (unpub.data) Susceptibilities tested during single challenge experiments
    8. 8. Treatments 1. Exposed turtle and unexposed tadpole 2. Exposed tadpole and unexposed turtle 3. Exposed fish and unexposed tadpole 4. Exposed tadpole and unexposed fish 5. Exposed tadpole and unexposed tadpole The control treatments were unexposed turtle and fish, turtle and tadpole, fish and tadpole, and tadpole and tadpole
    9. 9. Experiment • Direct exposure – Exposed to 103 PFU/mL – 3 days • 12-L containers divided in half by a 2000 µm plastic mesh • Different species in each side of the container
    10. 10. Infection Results • Turtles infected amphibians • Amphibians infected turtles • Fish infected Amphibians • Amphibians did not infected fish 50%30%10% 0 10 20 30 40 50 60 70 80 90 100 R | A F | A A | R A | F Infected(%) Treatment Direct Indirect * * 20% 50% 30% Cleared the infection after 28 days
    11. 11. Mortality Results • Not all species caused mortality • Turtles caused mortality in amphibians • Amphibians did not cause mortality in turtles • Fish caused mortality in Amphibians • Amphibians did not caused mortality in fish 50%10% 0 10 20 30 40 50 60 70 80 90 100 R | A F | A A | R A | F Mortality(%) Treatment Direct Indirect * * 28 Days 12% Amphibians and 100% turtles infected survived5% Amphibians infected survived20% infected turtles survived20% infected Fish survived
    12. 12. Turtle and Fish Results • All classes tested can transmit the virus • Turtles infected tadpoles – 50% mortality • Fish infected tadpoles – 10% mortality 50% 10%
    13. 13. Amphibian Results • Indirect mortality only in amphibians • Amphibians did not cause fish or turtle mortality • High indirect mortality
    14. 14. New Findings • Previous studies – Fish susceptible to amphibian ranavirus (Jensen et al. 2011, Moody and Owens 1994) – Turtle hatchlings susceptible to amphibian ranaviruses (Ariel 2007) – Amphibian susceptible to fish ranavirus (Bailey et al. 2013) • All previous studies – Direct exposure to ranavirus – Laboratory experiments • These is the first study to document: – Indirect transmission between ectothermic classes – Transmission between reptiles and fish
    15. 15. Conservation Implications • Interclass transmission can occur among ectothermic hosts • Reptiles and fish can present asymptomatic infections – Pass the infection to amphibians – Clear the infection • Fish and turtles could act as reservoirs of ranavirus when amphibians are absent • Interclass transmission can contribute to pathogen persistence and explain reoccurrence of die-offs
    16. 16. Acknowledgments • UT Institute of Agriculture – UT AgResearch Grant – UT College of Veterinary Medicine – Access and Diversity Fellowship (UT AgResearch) – Hazelwood Scholarship (CASNR) – UT-ESPN Scholarship (CASNR) – Society of Wetland Scientists Student Research Grant • Drs. Melissa Kennedy (CVM) • Dr. Mark Campbell and Roger Long (JARTU) • Jen Tucker • Technicians and Volunteers
    17. 17. Questions?? Contact: rbrenes@utk.edu mgray11@utk.edu dmille42@utk.edu

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