Adenoviruses in Wild Bog Turtles (Glyptemys muhlenbergii) of the Northeastern USA

Bog turtles (Glyptemys muhlenbergii) are critically endangered semiaquatic turtles inhabiting fens and bogs along the east coast of the USA. Threats to their survival include habitat loss from development, roads, altered hydrology, ecological succession, proliferation of invasive plants, poaching, and infectious disease. In response to an increase in bog turtle mortality and concerns about their health, we assessed bog turtle health and pathogen prevalence across five USA states-New York, Pennsylvania, New Jersey, Delaware, and Maryland-between 2014 and 2022. Adenoviruses, specifically barthadenovirus, or atadenoviruses, siadenoviruses, and testadenoviruses, have been associated with infection and disease in chelonians. To determine whether adenoviruses were present in free-ranging bog turtle populations, we tested archived choanal-cloacal swabs by PCR. Overall, 26 (49%) of 53 pooled samples collected between 2014 and 2018 and 9 (30%) of 30 samples collected in 2022 were positive for adenovirus. The DNA sequence and phylogenetic analyses revealed at least four distinct and novel lineages: Glyptemys adenovirus 1 (a testadenovirus first detected in Delaware and New Jersey in 2014 and in New York and Pennsylvania in 2016), Glyptemys adenovirus 2 (a testadenovirus detected in New Jersey and Pennsylvania in 2014), Glyptemys adenovirus 3 (an unclassified adenovirus detected in New Jersey in 2016), and Glyptemys adenovirus 4 (a siadenovirus detected in Maryland in 2016). None of these adenoviruses were associated with clinical signs or disease; however, knowledge of which pathogenic organisms are circulating in the bog turtle populations can inform decisions on monitoring, species recovery efforts, and captive breeding programs.