The invasive alien red-eared slider turtle, Trachemys scripta, as a carrier of STEF-disease pathogens

Development and analytical validation of a novel quantitative PCR assay for the detection of Trachemys herpesvirus 1

Emerging infectious diseases are a threat that contributes to the decline of global chelonian species. Herpesviruses are among the most impactful pathogens described in chelonians and are frequently associated with a range of presentations across hosts with the potential for severe morbidity and mortality. Trachemys herpesvirus 1 (TrHV1) has been reported in red-eared and yellow-bellied sliders (Trachemys scripta elegans and Trachemys scripta scripta, respectively) but is largely understudied. Invasive red-eared sliders may serve as a reservoir for transmission to sympatric native species. This study aimed to develop a sensitive and specific quantitative real-time PCR (qPCR) assay for the detection of TrHV1 DNA to aid in the characterization of the epidemiology of this virus in aquatic turtles. Two TaqMan-MGB FAM-dye labeled primer-probe sets were designed and evaluated using plasmid dilutions. The higher performing assay was specific for TrHV1 DNA and had a linear dynamic range of 1.0 × 107 to 1.0 × 101 copies per reaction with an R2 of 0.999, slope of -3.386, and efficiency of 97.39%. The limit of detection was 101 copies per reaction, and there was no loss of reaction efficiency in the presence of TrHV1-negative chelonian oral-cloacal DNA. Overall, the Trachemys herpesvirus 1 assay meets established criteria for acceptable qPCR assays and will be a valuable tool in characterizing the epidemiology of Trachemys herpesvirus 1 in chelonians.

Climate match is key to predict range expansion of the world's worst invasive terrestrial vertebrates

Understanding the determinants of the range expansion of invasive alien species is crucial for developing effective prevention and control strategies. Nevertheless, we still lack a global picture of the potential factors influencing the invaded range expansion across taxonomic groups, especially for the world's worst invaders with high ecological and economic impacts. Here, by extensively collecting data on 363 distributional ranges of 19 of world's worst invasive terrestrial vertebrates across 135 invaded administrative jurisdictions, we observed remarkable variations in the range expansion across species and taxonomic groups. After controlling for taxonomic and geographic pseudoreplicates, model averaging analyses based on generalized additive mixed-effect models showed that species in invaded regions having climates more similar to those of their native ranges tended to undergo a larger range expansion. In addition, as proxies of propagule pressure and human-assisted transportation, the number of introduction events and the road network density were also important predictors facilitating the range expansion. Further variance partitioning analyses validated the predominant role of climate match in explaining the range expansion. Our study demonstrated that regions with similar climates to their native ranges could still be prioritized to prevent the spread of invasive species under the sustained global change.

Mycotic Diseases in Chelonians

Turtles and 'tortoises' populations are declining in number, the factors driving extinction risks being related to habitat loss and degradation, climate change, introduction of invasive plant and animal species, consumption by humans for food and medicinal use, and collection for international pet trade. Fungal infections represent one of the main threats for ecosystem health. The present narrative review deals with conventional and emerging mycoses of Chelonians. Although conventional mycoses in captive and pet reptiles would depend on poor husbandry, being the agents mostly opportunistic pathogens, some fungal species were reported to occur more frequently, such as the entomopathogen Purpureocillium lilacinum. Furthermore, emerging agents such as the Fusarium solani species complex have been recognized as a real threat for the surviving of some aquatic species, acting as primary pathogens. This complex has been recently included within pathogens in One Health issues. Emydomyces testavorans is recognized as an emerging threat, although, due its recent identification, information about its epidemiology is limited. Data about treatments and outcomes of mycoses in Chelonians are also referred.

Status and Analysis of Artificial Breeding and Management of Aquatic Turtles in China

Simple Summary

Turtles have been on Earth for 300 million years, but their survival has been challenged as human activity has expanded. The results of a census and statistical analysis of artificially domesticated aquatic turtles in 15 provinces of China showed that 29 species were aquatic turtles native to China and a large number of exotic aquatic turtles are domesticated in China. This paper presents the current situation and problems of aquaculture and conservation of aquatic turtles in major provinces of China, and puts forward some suggestions for the conservation and management of aquatic turtles.

Abstract

China is a major country in turtle cultivation and has a long history of artificial breeding of turtles. In this study, a census and statistical analysis of artificially domesticated aquatic turtles in 15 provinces of China were conducted. The results showed that 29 species were aquatic turtles native to China, accounting for approximately 9% of the world’s total, and a large number of exotic aquatic turtles are also domesticated in China. The present situation of artificial breeding and protection of aquatic turtles in major provinces of China is shown, and existing problems are also put forward, with suggestions for the protection and management of aquatic turtles.

Detection of a Novel Chlamydia Species in Invasive Turtles

Simple Summary

The pond slider (Trachemys scripta) is a turtle species native to Central America. Pond sliders have been commercialized as pets since the 1950s, but often ended up being released or escaping into an environment to which they are allochthonous. Trachemys scripta is presently classified as an invasive alien species in Europe and other countries. The introduction of pond sliders in foreign ecosystems has had a deep environmental and ecological impact. Moreover, freed or escaped captive turtles could be carriers of pathogens, such as Chlamydiaceae. In this study, we report the identification of a Chlamydia spp. in two pond sliders found dead after the hibernation period. Further molecular characterization revealed that this Chlamydia is identical to a strain reported in Poland in 2017, found in both captive and free-living freshwater turtles, and has a close phylogenetic relationship to Chlamydia pneumoniae, a species infectious to humans, and to chlamydial strains found in other reptiles. This first finding evidences the presence of this novel Chlamydia in Italian turtles, but further studies will be necessary to evaluate the prevalence in the local turtles’ population and the strain pathogenicity.

Abstract

Trachemys scripta is a turtle species native to Central America. Since the 1950s, pond sliders have been imported worldwide as companion animals, but have often ended up in foreign ecosystems with great ecological consequences. Moreover, both autochthonous and invasive species of turtles can be carriers of pathogens, including Chlamydiaceae. In the present study, pulmonary tissues collected from four Trachemys scripta were tested with a 23S-targeting real-time PCR (rPCR) specific for the Chlamydiaceae family. The turtles were hosted in a rescue center for wild exotic animals located in northeastern Italy, and were found dead after the hibernation period. Two out of four individuals resulted positive in rPCR for the presence of Chlamydiaceae. Further characterization of this positivity was performed by phylogenetic analysis of the 16S rRNA and outer membrane protein A genes. The phylogenetic tree showed that these chlamydial strains are identical to a novel Chlamydia reported in 2017 in Polish freshwater turtles, and closely related to Chlamydia pneumoniae and to other chlamydial strains found in reptiles. This first finding evidences the presence of this Chlamydia strain in Italian turtles, but further studies will be necessary to confirm the presence and the strain pathogenicity and to evaluate its prevalence in the local turtles’ population.