Frog virus 3 in eastern box turtles: agents seen with coinfections
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Transcript of Frog virus 3 in eastern box turtles: agents seen with coinfections
Frog Virus 3 in Eastern Box Turtles: Agents seen with Coinfections
James F.X. Wellehan Jr., DVM, PhD, DACZM, DACVM (Virology, Bacteriology/Mycology), Natalie H. Hall, DVM,
DACZM, Gregory J Fleming, DVM, DACZM, April L. Childress, Scott P. Terrell, DVM, DACVP
North American Box TurtlesTerrapene sp.
• Low Fecundity• Low Juvenile Survival Rate• Long Lifespan• Cryptic• Frog Virus 3 Mortality Events Well
Documented
Coinfections
• Koch’s Postulates easily misinterpreted as dichotomous pathogen/nonpathogen
Host
Pathogen Environment
Coinfections
• Coinfections with Rotavirus and other enteric pathogens are synergistic (Bhavnani et al, 2012)
• Coinfections with Marek’s disease and Cryptosporidium baileyi in chickens synergistic (Abbassi et al, 2000)
Iridoviruses
• Enveloped, but infective without envelope– Stable in environment
• Cytoplasmic• Less host specific than herpes/adeno
Iridoviruses
• Genus Ranavirus– Signs:
• Stomatitis,Hepatitis, Splenitis,Enterocolitis– Frog Virus 3 is the best studied pathogen of
box turtles• Also found in amphibians,sturgeon, other
turtles.
Eastern Box Turtles
• Confiscated• Placed at quarantine of large well-run zoo• High mortality rate• 8 turtles submitted for testing
Herpesviruses
• Enveloped virus, not stable in environment• Diverse, coevolved with hosts
– Often high infection rates in endemic hosts– 8 species endemic in one primate species
• Intranuclear• Latency
– Typically infected for life• One genus reported in turtles- Scutavirus
Box Turtle Scutaviruses
• Terrapene HV1– Seen in Eastern Box Turtles– Commonly seen in coinfections with Frog Virus 3– Role in disease under investigation
• Terrapene HV2– Seen in Eastern Box Turtle– Identified in fibropapillomatous lesion
Scutavirus
Iltovirus
Simplexvirus
Varicellovirus
ProboscivirusCytomegalovirusMuromegalovirusRoseolovirus
Lymphocryptovirus
Rhadinovirus
Percavirus
Macavirus
Mardivirus
Adenoviruses
• Non-enveloped– Very stable in environment
• Intranuclear• Diverse, coevolved with hosts
– 6 species endemic in one primate species– Generally host specific, may jump to close
relatives• Eublepharid AdV1 - leopard & fat tailed geckos,
Helodermatid AdV2 – Gila monsters & Pogona
Adenoviruses
• Novel chelonian genus– Box turtles, Red eared sliders, Pancake tortoises– Signs:
• Depression, weight loss
Siadenovirus
Aviadenovirus
Mastadenovirus
Atadenovirus
Novel Turtle Genus
Ichtadenovirus
Tenericutes
• Important bacterial phylum• Mycoplasma, Ureaplasma, Acholeplasma
– Have lost cell wall– More difficult to grow– Dependent on host cells– Range from relatively benign to significant
pathogens• Not beneficial
Mycoplasma
• Mycoplasma sp.– Associated with upper respiratory disease in
box turtles– First reported by Feldman et al, 2006– Distinct from M. agassizii seen in Gopherus sp.– Additional species recently discovered, clinical
significance still under investigation
Confiscated turtlesTurtle Ranavirus Herpes Adeno Mycoplasma
1 - TerHV1 Ornate BTAdV1 Mycoplasma sp. BT
2 - TerHV1 Ornate BTAdV1 Mycoplasma sp. BT
3 - TerHV1 Ornate BTAdV1 Mycoplasma sp. BT
4 FV3 TerHV1 Ornate BTAdV1 Mycoplasma sp. BT
5 - - Ornate BTAdV1 Mycoplasma sp. BT
6 FV3 - Ornate BTAdV1 Mycoplasma sp. BT
7 FV3 - Ornate BTAdV1 Mycoplasma sp. BT
8 - - Ornate BTAdV1 Mycoplasma sp. BT
Future Directions
• Quantitative assays for measurement of agent loads
• Surveillance of wider populations
Thanks