Epidemiology of Emydoidea Herpesvirus 1 in free-ranging Blanding’s turtles (Emydoidea Blandingii) from Illinois

["Blandings turtle";chelonian;Emydoidea blandingii;epidemiology;herpesvirus;quantitative PCR

Lindemann, Dana Marie ; Ossiboff, Robert J, ; ,Thompson, Dan, ; ,Langan, Jennifer ; Allender ; Matthew C.

关键词: ["Blandings turtle";    chelonian;    Emydoidea blandingii;    epidemiology;    herpesvirus;    quantitative PCR;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/99249/LINDEMANN-THESIS-2017.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

While herpesvirus infections have been associated with high morbidity and mortality in populations of captive Emydid chelonians worldwide, novel herpesviruses (Terrapene herpesvirus 1, Emydid herpesvirus 1 and 2, and Glyptemys herpesvirus 1 and 2) have also recently been identified in apparently healthy free-ranging Emydid populations. The clinical significance of this finding in the absence of an outbreak is currently unknown. The authors hypothesize that herpesvirus prevalence may be used as a sentinel of population health due to the virus’ propensity to recrudesce in times of stress or concurrent disease. Blanding’s turtles (Emydoidea blandingii), an endangered species in Illinois, have experienced range-wide declines because of habitat loss, degradation, and fragmentation. While ongoing studies are crucial to a thorough understanding of the natural history and demographics in disjointed Illinois populations, infectious disease threats have been largely unevaluated. In 2015, 20 free-ranging Blanding’s turtles in DuPage County, Illinois were screened for a herpesvirus using consensus PCR. A novel herpesvirus, Emydoidea herpesvirus 1 (EBHV1), was identified. Subsequently, the investigators developed a highly sensitive and specific TaqMan® quantitative PCR assay to target the DNA-dependent DNA polymerase gene of EBHV1. Validation results indicate that this assay is specific for EBHV1, has a linear range of detection from 108-101 viral copies per reaction, and can categorically detect as few as 1 viral copy per reaction. In an epidemiological investigation, combined oral-cloacal swabs were collected from radiotelemetered and trapped Blanding’s turtles in DuPage (n=60 turtles) and Lake (n=81 turtles) County from May-September 2016. Repeated samples of 50 adult females had a significantly higher prevalence of EBHV1 in May (23.8%, n=10) than June (2.9%, n=1), July (0%, n=0), August (0%, n=0), or September (7.7%, n=3) (odds ratio [OR]: 12.97; 95% CI: 3.83-43.92). This corresponds to the onset of nesting and may be associated with increased physiologic demands; however, all positive turtles were negative in subsequent months. Furthermore, there were no clinical signs associated with any turtle at the time they were detected with EBHV1. This investigation is the critical first step to characterizing the implications of EBHV1 on Blanding’s turtle population health and identifying management changes that may improve sustainability.