Drivers and Impacts of Single and Co-Pathogen Occurrence in Free-Living Eastern Box Turtles (Terrapene carolina carolina) in Illinois and Tennessee USA, 2013–2016
Wildlife Epidemiology Laboratory, College of Veterinary Medicine, University of Illinois, Urbana, IL, USA
Infectious diseases are increasingly detected in free-living herptiles, but their clinical significance is not always obvious. The impacts of Terrapene herpesvirus 1 (TerHV1) and adenovirus (AV) on Eastern box turtle (Terrapene carolina carolina) health are largely unknown.7,11 Other pathogens, such as frog virus 3 (FV3), have known effects (mortality), but epidemiology in free-living populations is poorly characterized.1,3,5,6,8,10 This study describes comprehensive health assessments, including qPCR testing for three pathogens simultaneously, in 724 free-living Eastern box turtles sampled from 2013–2016 in Illinois and Tennessee, USA.2,4,9 The purpose was to identify factors associated with qPCR detection of TerHV1, AV, FV3, and co-infections. Single pathogens were detected in 249 turtles (15 FV3, 196 TerHV1, 35 AV). Co-infection was detected in 18 turtles (3 FV3 & TerHV1, 15 TerHV1 & AV). Season, state, substrate, location, sex, age class, nasal discharge, oral plaques, and increases in leukocyte count, heterophil count, and monocyte count were significantly associated with qPCR detection of FV3 (p<0.05). Year, season, physical examination abnormalities, increases in PCV and TS, and decreases in lymphocyte count and monocyte count were associated with TerHV1 detection (p<0.05). Sex, year, age class, weight, and body condition were associated with AV detection (p<0.05). Sex and increased lymphocyte count were associated with co-detection of TerHV1 and AV (p<0.05). This is the first large-scale study to document host and environmental factors influencing single and co-pathogen dynamics in Eastern box turtles. It provides a valuable starting point for understanding the drivers and impacts of disease in free-living box turtles.
The authors thank John Rucker, the turtle dogs, the herpetologists at the Illinois Natural History Survey, and the turtle team veterinary students for their assistance with turtle location and sample collection. Authors thank Elena Dzhaman for invaluable assistance with sample processing.
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