Development and validation of a quantitative PCR assay for detection of Terrapene herpesvirus 2 in eastern box turtles (Terrapene carolina carolina)

CUTANEOUS MYIASIS AND ITS RELATIONSHIP TO WELLNESS IN EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA) IN CAPE COD, MASSACHUSETTS

Eastern box turtles (Terrapene carolina carolina) face a variety of anthropogenic, infectious, and environmental threats and have been affected by high morbidity and mortality disease events. Wellness parameters in free-ranging eastern box turtles with a high prevalence of myiasis on Cape Cod, MA, were documented to identify epidemiologic trends or associations with several health parameters. There were 109 samples collected from 59 individual box turtles over the course of 4 mon. Six turtles died over the course of this study. Fly larvae infestations varied in severity and were observed in the cutaneous and subcutaneous tissue (n = 18; 30.5%). Animals with myiasis had fewer plastron abnormalities than those without (P = 0.034), and all turtles found in bogs had evidence of fly larvae infections (P < 0.0001). Individuals with myiasis also had lower body condition index (P = 0.014), lower total white blood cells (P = 0.031), lower PCV (P < 0.0001), lower total solids (P < 0.0001), higher erythrocyte sedimentation rate (P < 0.0001), lower calcium (P = 0.018), and lower phosphorus (P = 0.017). Three turtles tested positive for terrapene herpesvirus 1, but presence was not associated with myiasis. Heavy metal analysis revealed no significant differences between turtles with and without myiasis. This study examined the health of a population of eastern box turtles, and continued health assessments will be beneficial in determining the impact of myiasis on future conservation plans.

Multiplex real-time PCR for the detection and differentiation of equid gammaherpesvirus 2 and 5

Equid gammaherpesvirus 2 (EHV-2) and 5 (EHV-5) are widely distributed in the equines. Although their pathogenic potential is not yet fully understood, they appear to play a role in disease patterns like equine multinodular pulmonary fibrosis. In this study, a multiplex real-time PCR (rtPCR) was designed to detect DNA of the glycoprotein H (EHV-2) and E11 gene (EHV-5). Analytical specificity was determined by testing DNA of other herpesviruses by SYBR Green rtPCR and melting curve analysis, as well as Sanger sequencing of positive field samples. Analytical sensitivity was assessed by standard curve generation of serial plasmid dilutions containing the respective target gene. Melting curves and BLAST analysis of the sequences indicated specific detection of the viruses. The lower limit of detection of the singleplex rtPCR was 40 and 29 DNA copies per reaction for EHV-2 and EHV-5, respectively. Comparison of the Ct values of a selection of positive field samples showed only minimal differences between the singleplex and the multiplex assay. The here described multiplex rtPCR protocol allows sensitive and specific detection of EHV-2 and EHV-5. It represents a convenient and rapid tool for future studies to investigate the clinical relevance of EHV-2 and EHV-5 in more detail.

Herpesviruses in Captive Chelonians in Europe Between 2016 and 2020

Herpesviruses are important pathogens in tortoises and turtles, yet little is known about the epidemiology of these viruses. We analyzed herpesviruses detected by PCR in samples from captive chelonians in Europe according to virus strain, host species, year and season in which the animal was tested, and country in which the animal was kept. A total of 4,797 samples submitted to a diagnostic laboratory in Europe between January 2016 and December 2020 were evaluated. Of these, 312 (6.50%) were positive for herpesviruses. The types most commonly found were testudinid herpesvirus (TeHV)1 (143 positive, 45.83%) and TeHV3 (153 positive, 49.04%), but also included TeHV2 (1 positive, 0.32%), TeHV4 (3 positive, 0.96%), Terrapene herpesvirus 1 (7 positive, 2.24%), Trachemys herpesvirus 1 (2 positive, 0.64%), and three previously undescribed herpesviruses (0.96%). Herpesviruses were detected in chelonians in the families Testudinidae, Emydidae, Geoemydidae, and in the suborder Pleurodira. Among the species for which 100 samples or more were available, the highest proportions of positive samples (positivity rates) were found in samples from Horsfield's tortoises (Testudo horsfieldii) (14.96%), and radiated tortoises (Astrochelys radiata) (14.05%). Among tortoises (Testudinidae), viruses were most often detected in the spring, while in emydid turtles (Emydidae) they were most often detected in the summer. A comparison of the positivity rates according to country showed significant differences, with the highest rate in samples from Italy (16.01%). This study indicated possible differences in herpesvirus positivity rates depending on host species, virus strain, year of sampling, season, and country of origin. It provides useful information in further understanding fluctuations in infection rates as well as in helping to guide decision making for herpesvirus diagnostics in chelonian patients. It also provides evidence for the international dispersal of herpesviruses with their hosts through international trade.

PREVALENCE AND ANTIMICROBIAL RESISTANCE PATTERNS OF SALMONELLA SPP. IN TWO FREE-RANGING POPULATIONS OF EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA)

Salmonellosis is an important zoonotic infection, and exposure to pet reptiles has been implicated in several human outbreaks. Although several studies report a low prevalence of salmonellae in free-ranging chelonians, they may serve as a reservoir. In spring and summer of 2013 and 2019, free-ranging eastern box turtles (Terrapene carolina carolina) from populations in Illinois (rural) and Tennessee (urban) were collected through canine and visual search. Cloacal swab samples were collected from each turtle, selectively enriched with tetrathionate broth, then plated on selective and differential media to isolate Salmonella spp. Genus was confirmed via MALDI-TOF MS and antibiotic sensitivities were performed. Isolates were serotyped by the National Veterinary Services Laboratory. Of the 341 turtles sampled, Salmonella spp. were detected in nine individuals (2.64%; 95% CI: 1.2-5.0%). The isolates included five different serovars: Anatum (n = 2), Newport (n = 2), Thompson (n = 1), Bareilly (n = 2), and Hartford (n = 2). Salmonella spp. were detected from six animals in 2013 (3.19%, 95% CI: 1.2-6.8%) and three in 2019 (1.96%, 95% CI: 0.4-5.6%). There was no significant difference in prevalence between state, (P = 0.115), Illinois locations (P = 0.224), season (P = 0.525), year (P = 0.297), sex (P = 0.435), or age class (P = 0.549). The health of Salmonella-positive and -negative turtles was not significantly different, as assessed through hematology and plasma biochemistry (P > 0.05), indicating asymptomatic carrier status. The low prevalence detected in this study likely concludes that free-ranging eastern box turtles play a minimal role in the spread of salmonellae. However, the identified serotypes are potentially human- and animal-pathogenic. Documenting the prevalence of Salmonella serotypes in animal indicators furthers our understanding of their spread between humans, animal agriculture, and the environment.