Debra L. Miller, DVM, PhD - University of...

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Comparative Pathology of Comparative Pathology of RanaviralRanaviral Disease among Disease among

Amphibians, Reptiles and FishAmphibians, Reptiles and Fish

Debra L. Miller, DVM, PhDDebra L. Miller, DVM, PhD

Center for Wildlife Health and Center for Wildlife Health and Department Pathobiology Department Pathobiology University of TennesseeUniversity of Tennessee

Amphibians

Swelling (most often edema) Erythema, Ulcerations

Photo courtesy Nathan Haislip

D. Green, USGSPhoto, Betsie B. Rothermel

Photo courtesy Nathan Haislip

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May vary by life stage May vary by life stage [adults most reported from Europe, but elsewhere too][adults most reported from Europe, but elsewhere too]

Photo courtesy Nathan Haislip

Photo courtesy Nathan Haislip

Varies by host (species)Varies by host (species)--susceptibility & isolatesusceptibility & isolate(e.g., mortality: RI [ranaculture isolate] (e.g., mortality: RI [ranaculture isolate] vsvs FV3)FV3)

Cope’s tree frog (~70% RI; ~40% FV3)

Photo courtesy Nathan Haislip

Wood frog (~ 100% for both)

Bullfrog (~10%; 0% FV3)

Cope s tree frog (~70% RI; ~40% FV3)Photo courtesy Nathan Haislip

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Internal lesions

hemorrhage

mesonephros

pale, swollen organsfat bodies

spleen

tan areas [necrosis] on organs

HistologyHistology

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HistologyHistology

Southern Southern Leopard Leopard Frog: Frog:

ll

control

spleenspleen

FV3ranaculture isolate

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Southern Southern Leopard Leopard Frog: Frog: kidkid

control

kidney kidney ((mesonephrosmesonephros))

FV3ranaculture isolate

Pallid sturgeon isolate Ranaculture isolate

Wood Frog Spleen

FV3 Box turtle isolate

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In North GeorgiaIn North Georgiaconcurrent in morbid concurrent in morbid Notophthalmus viridescens Notophthalmus viridescens andandLithobates clamitansLithobates clamitans. .

Photo, Betsie B. Rothermel

RanavirusRanavirus--positive animalspositive animalsplus: Parasites increasedplus: Parasites increased

In Tennessee: Die-off in L. clamitans, L. catesbeianus, N.

viridescens

plus: Parasites increasedplus: Parasites increased

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What about reptiles?What about reptiles?

SCWDS caseSCWDS case(slides courtesy of Dr. Mark Ruder)(slides courtesy of Dr. Mark Ruder)

Eastern box turtle (Eastern box turtle (TerrapeneTerrapene carolinacarolina carolinacarolina))

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Gross Findings (cont.)Gross Findings (cont.)

5 mm

Some microscopic Some microscopic ffindingsindings

Myofibers disrupted

Ulcerated crust on oral mucosa

Disrupted muscle fibers

Heterophillic vasculitis

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DiagnosticsDiagnostics RanavirusRanavirus isolated in tissue cultureisolated in tissue culture

Partial sequencing yielded Frog virus 3Partial sequencing yielded Frog virus 3–– Partial sequencing yielded Frog virus 3Partial sequencing yielded Frog virus 3

PCR on PCR on oropharyngealoropharyngeal swab and nasal swab and nasal flushflush–– RanavirusRanavirus –– positivepositive–– HerpesvirusHerpesvirus and and MycoplasmaMycoplasma -- negativenegativepp y py p gg

MycoplasmaMycoplasma culture of nasal flushculture of nasal flush–– NegativeNegative

What about water turtles?What about water turtles?

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Concurrent infections compound the diagnosis

ParasitismParasitism ParasitismParasitism–– Soft shells Soft shells

Spirorchid eggs (often systemic) Entomeoba spp trophozoites

(intestines only)

Bacterial EnteritisBacterial Enteritis–– SSlidersliders

Current investigation:Current investigation:

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What about Fish?What about Fish?

Ecchymosis and petechiation on the ventral surfacePale gills and liver

FishFish--creek chubcreek chub

Pale gills and liverFriable kidneys and liver Lesions/organs PCR positive for ranavirus

Photo courtesy Emilie Travis

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Pallid Sturgeon Isolate Pallid Sturgeon Isolate from mortality eventfrom mortality event

Photos Courtesy Tom Waltzek

Hematopoietic necrosis; tubular epithelial necrosis

E d h liEndothelium

Endothelial necrosis

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Liver: Portal triad: endothelial necrosis (arrow) Also: hematopoietic necrosis (arrow head).

Planned investigation:Planned investigation:

Pilot study: fish challenges (Fall 2011)

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AcknowledgementsAcknowledgements

Matt GrayMatt Gray Sandy BaldwinSandy Baldwin Jason HovermanJason Hoverman Betsie RothermelBetsie Rothermel Mark RuderMark Ruder Tom WaltzekTom Waltzek Nate HilzingerNate Hilzinger

Lisa WhittingtonLisa Whittington Dallas IngramDallas Ingram Diane Diane RouseyRousey Kim BridgesKim Bridges Melissa GandyMelissa Gandy

Becky HardmanBecky Hardman Nathan HaislipNathan Haislip Roberto BrenesRoberto Brenes Sean RoonSean Roon

Eloise Eloise StyerStyer Emilie TravisEmilie Travis Kevin KeelKevin Keel Various zoos and aquariaVarious zoos and aquaria

Questions?Questions?