A Severe Ranavirus Outbreak in Captive, Wild-Caught Box Turtles.

Area of Science:

• Herpetology
• Wildlife Disease Ecology
• Veterinary Virology

Background:

• Ranaviruses are emerging infectious pathogens affecting a wide range of ectothermic animals.
• Captive populations, especially those undergoing translocation, can be vulnerable to disease outbreaks.
• Understanding ranavirus dynamics in vulnerable populations is crucial for conservation efforts.

Purpose of the Study:

• To monitor a Ranavirus outbreak in a captive population of wild box turtles.
• To assess the impact of ranavirus on population mortality and infection rates.
• To investigate factors influencing ranavirus prevalence and identify potential host tolerance.

Main Methods:

• Clinical evaluations and real-time PCR were used to monitor 317 wild box turtles over two years.
• Infection rates were assessed across different sampling periods.
• Correlation between clinical signs and infection status was analyzed, along with agreement between sample types.

Main Results:

• The study population experienced 71.6% mortality during the observation period.
• Ranavirus infection rates varied widely (7-94%) between sampling periods.
• Only nasal clinical signs correlated significantly with infection status; sample type agreement was low.
• Post-outbreak, low mortality persisted alongside high ranavirus prevalence, indicating potential host tolerance.

Conclusions:

• Ranaviruses can cause rapid population declines in susceptible wildlife.
• Variable infection rates suggest complex dynamics including potential pathogen clearance and reinfection or imperfect detection.
• Surviving box turtles may exhibit tolerance to ranavirus, warranting further investigation into immune mechanisms.