Javier G. Nevarez - Blackwell's Five-Minute Veterinary Consult - Reptile and Amphibian

In aquatic turtles, HV have been described in various emydid species, including pond, painted, map, and box turtles as well as in other taxonomic groups of turtles.

Disease can occur year round, although tortoises may be particularly susceptible in the spring and fall.

Fibropapillomatosis: can develop externally on all parts of the body, including the eyes and around the cloaca, leading to difficulties in finding food and/or in defecating. Internal tumors can also occur. Affected animals may be cachectic.

Other HV‐associated diseases described in sea turtles: gray patch disease (skin lesions in young green sea turtles); LETD (respiratory disease in green sea turtles); LGRV, and LOCV in wild‐caught loggerhead sea turtles.

Acute: lethargy, anorexia, caseous plaques on the tongue and palate, dyspnea, hepatitis. Severe disease with high morbidity and mortality associated with TeHV3 infection in various tortoise species. Infection may be clinically inapparent in some cases, although disease can develop in any species. TeHV1 and TeHV4 may be associated with less severe disease or inapparent infections.

Chronic: surviving tortoises may develop CNS signs, including paralysis or incoordination. Clinically healthy carriers are also possible.

Sudden death, weakness, nasal discharge, stomatitis, papillomatosis, and hepatitis.

Herpesviruses have also been detected in apparently clinically healthy animals.

Mixing of different tortoise species leads to an increase in the probability of inapparent carriers transmitting virus to highly susceptible species.

In sea turtles, sudden changes in temperature and exposure to environmental pollutants have both been shown to increase susceptibility to HV disease.

N/A

In tortoises: depending on the presentation, mycoplasma infections (esp. in cases with upper respiratory disease), ranavirus (family Iridoviridae) infections, topivirus

(family Picornaviridae) infections, bacterial and/or fungal stomatitis.

Most commonly done using PCR detection of viral DNA.

A pan‐HV PCR can be used to detect all reptilian HV described so far.

PCRs for specific chelonian HV have also been described.

In sea turtles, material from fibropapillomas should be used for testing; in tortoises oral swabs, tongue, liver and brain can be tested.

Material from any lesions observed should be included in any testing scheme.

Virus neutralization tests have been used for the detection of antibodies against TeHV1 and 3 in tortoises.

An ELISA has also been described for the detection of antibodies against these two viruses and against TeHV2, but may not be commercially available.

Ballooning degeneration and necrosis may be noted in infected epithelial cells, necrosis and inflammation in affected tissues.

Fibropapillomas consist of a hyperplastic epidermis and a thickened hypercellular dermis.

Infected cells may contain eosinophilic to amphophilic intranuclear inclusions.

There are no standardized protocols for treating HV‐infected reptiles.

Strict quarantine, biosecurity, and hygiene are essential for the prevention of HV infections.

Autovaccination with inactivated material from surgically removed fibropapillomas has been suggested.

Keeping animals at the high end of their POTZ may help in recovery, as well as treatment of secondary bacterial infections.

Herpesvirus infected reptiles may be anorexic and nutritional support may be necessary.

In animals with oral lesions, esophagostomy tubes may be necessary.

Testing for both virus and antibodies (in tortoises) should be in place.

An effective quarantine regimen should be in place.

Mixing of tortoise species should be avoided.

Infected animals must be isolated

For fibropapillomas—surgical removal of lesions.

Acyclovir 80 mg/kg PO q24h (famciclovir has been shown to be safer in mammals and may be an alternative choice for treatment).

Acyclovir topically on lesions or topical disinfection (e.g., with 0.5% chlorhexidine solution) have also been suggested.

The use of immunomodulators (e.g., Zylexis (Pfizer AG, Zurich, Switzerland)) has been suggested in HV infected tortoises, but its efficacy is unproven.

Affected animals should be barrier nursed and in‐contact animals should be placed in quarantine.

Development of disease in contact animals may take several weeks, so monitoring of a collection (and barrier nursing of contact animals) should remain active for at least one season.

There is some indication that brumation may provoke disease outbreaks, and intensified health monitoring should be carried out in the spring and again before the next brumation.

Morbidity and mortality can be high, depending on the virus strain and host species involved, although it can take an extended period of time for the disease to run its course within a collection.

Surviving animals remain carriers

N/A

Herpesviruses of reptiles have not been shown to be zoonotic.

Fibropapillomatosis (FP) in sea turtles

chHV5 = chelonid alphaherpesvirus 5

CNS = central nervous system

ELISA = enzyme‐linked immunosorbent assay

FPTHV = fibropapillomatosis‐associated turtle herpesvirus

HV = herpesvirus

LETD = lung = eye = and trachea disease

LEDV = lung = eye = and trachea disease virus

LGRV = loggerhead genital–respiratory herpesvirus

LOCV = loggerhead orocutaneous herpesvirus

PCR = polymerase chain reaction

POTZ = preferred optimal temperature zone

TeHV = testudinid herpesvirus