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372 result(s) for "Turtles - parasitology"
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Health assessment of non-native red-eared sliders (Trachemys scripta elegans) and their impact potential on native species
Red-eared sliders (RES; Trachemys scripta elegans ) are a globally invasive species that can impact native chelonian populations through resource competition and disease introduction. In Cook County, Illinois, invasive RES co-occur with, and greatly outnumber, a species of conservation priority in the Great Lakes region: the Blanding’s turtle ( Emydoidea blandingii ). This study sampled free-ranging RES in Cook County during spring, summer, and fall in four unique locations to characterize the possible effect of this non-native species on the health of regional, sympatric, aquatic chelonians. RES (n = 242) were captured and sampled for qPCR pathogen detection, clinical pathology, and necropsy from 2018 to 2022. Multiple pathogens were detected, including Mycoplasma spp., multiple adenoviruses, Trachemys herpesvirus 1 (TrHV-1), frog virus 3, human-pathogenic Leptospira spp., Emydomyces testavorans , and Salmonella typhimurium . Mycoplasma spp. prevalence was significantly higher (p < 0.05) at one isolated site with a suspected greater density of turtles. Detection of TrHV-1 was significantly associated with season (p < 0.001), with detections occurring only in spring and fall. For the 28 hematology, plasma biochemistry, and protein electrophoresis analytes assayed, significant and variable associations occurred based on sample year, season, pathogen detection, age, and sex. Population-based reference intervals were created for hematologic, plasma biochemistry, and plasma protein electrophoresis analytes. Common necropsy findings included mild endoparasitism and related vascular lesions such as endarteritis. Notably, qPCR detection of above pathogens was not associated with any gross or histologic lesions indicative of clinically relevant disease. This study indicates that invasive RES in Cook County may be infected with pathogens of concern for co-occurring turtle species, and absence of associated lesions in the RES suggests they likely serve as carrier species for these pathogens. Continued health monitoring of this species is important as interactions with chelonians of conservation priority increase.
Unoculubranchiobdella sp. (Hirudinea: Ozobranchidae) as a vector for Haemogregarina spp. in freshwater turtles from Brazil
Species of Haemogregarina are blood parasites known to parasitise vertebrate hosts, including fishes ( Haemogregarina sensu lato) and freshwater turtles ( Haemogregarina sensu stricto). Their vectors, include gnathiid isopods and leeches, respectively. In turtles, Haemogregarina balli has the best-characterized life cycle in the genus. However, no studies in Brazil have suggested a possible vector for any species of Haemogregarina from freshwater turtles. Therefore, in the present study, we provide insights into a leech vector based on specimens found feeding on two species of freshwater turtles, Podocnemis unifilis and Podocnemis expansa , using morphological and molecular data . In 2017 and 2019, freshwater turtles were collected in Goiás State, Brazil. Hosts were inspected for ectoparasites and leeches were collected from two specimens of P. expansa and nine specimens of P. unifilis . Leeches were subsequently identified as members of the genus Unoculubranchiobdella. Leech histological slides revealed haemogregarine-like structures, similar to post-sporogonic merogony, found near the gills and within the posterior sucker. Molecular analysis of the haemeogregarines resulted in the identification of three species of Haemogregarina : Haemogregarina embaubali, Haemogregarina goianensis, and Haemogregarina brasiliana . Therefore, our findings, based on morphology and DNA data suggest leeches of the genus Unoculubranchiondella as vectors for at least three species of Haemogregarina from Brazilian turtles.
Molecular Identification of Juvenile Neoechinorhynchus spp. (Phylum: Acanthocephala) Infecting Ostracod and Snail Hosts Provides Insight into Acanthocephalan Host Use
The role of invertebrates in some acanthocephalan life cycles is unclear because juvenile acanthocephalans are difficult to identify to species using morphology. Most reports suggest acanthocephalans from turtle definitive hosts use ostracods as intermediate hosts and snails as paratenic hosts. However, laboratory studies of the life cycle suggest that ostracods and snails are both required hosts in the life cycle. To elucidate the role of ostracods and snails in acanthocephalan life cycles better, we collected 558 freshwater snails of 2 species, including Planorbella cf. Planorbella trivolvis and Physa acuta, from 23 wetlands in Oklahoma, U.S.A., and examined them for acanthocephalan infections. Additionally, we examined 37,208 ostracods of 4 species, Physocypria sp. (morphotype 1), Cypridopsis sp., Stenocypris sp., and Physocypria sp. (morphotype 2) for juvenile acanthocephalans from 2 wetlands in Oklahoma. Juvenile acanthocephalans were morphologically characterized, and the complete internal transcribed spacer (ITS) region of nuclear rDNA was sequenced from acanthocephalans infecting 11 ostracod and 13 snail hosts. We also sampled 10 red-eared slider turtles, Trachemys scripta elegans, and 1 common map turtle, Graptemys geographica, collected from Oklahoma, Arkansas, and Texas and recovered 1,854 adult acanthocephalans of 4 species. The ITS of 17 adult acanthocephalans of 4 species from turtle hosts were sequenced and compared to juvenile acanthocephalan sequences from ostracod and snail hosts from this study and GenBank to determine conspecificity. Of the 23 locations sampled for snails, 7 (30%) were positive for juvenile acanthocephalans in the genus Neoechinorhynchus. The overall prevalence and mean intensity of acanthocephalans in Planorbella cf. P. trivolvis and P. acuta were 20% and 2 (1–6) and 2% and 1 (1), respectively. In contrast, only 1 of 4 species of ostracods, Physocypria sp. (morphotype 1), was infected with larval/juvenile Neoechinorhynchus spp. with an overall prevalence of 0.1% and a mean intensity of 1 (1–2). Although 4 species of acanthocephalans infected turtle definitive hosts, including Neoechinorhynchus chrysemydis, Neoechinorhynchus emydis, Neoechinorhynchus emyditoides, and Neoechinorhynchus pseudemydis, all the ITS sequences from cystacanths infecting snail hosts were conspecific with N. emydis. In contrast, the ITS sequences from larval/juvenile acanthocephalans from ostracods were conspecific with 2 species of acanthocephalans from turtles (N. emydis and N. pseudemydis) and 1 species of acanthocephalan from fish (Neoechinorhynchus cylindratus). These results indicate that N. emydis infects freshwater snails, whereas other species of Neoechinorhynchus appear not to infect snail hosts. We document new ostracod and snail hosts for Neoechinorhynchus species, including the first report of an ostracod host for N. pseudemydis, and we provide novel molecular barcodes that can be used to determine larva, juvenile, and adult conspecificity of Neoechinorhynchus species.
Description and Phylogenetic Position of a New Species of Herpetodiplostomum from Phrynops geoffroanus in Brazil and a Reevaluation of Cheloniodiplostomum
As presently recognized, Herpetodiplostomum is a small genus of proterodiplostomid digeneans parasitic in crocodilians. Most members of Cheloniodiplostomum, a genus of proterodiplostomids that parasitize chelonians, were originally placed within Herpetodiplostomum. The 2 genera were distinguished based on the presence/absence of papillae on the holdfast organ and anterior extent of vitellarium. Our study of Herpetodiplostomum and Cheloniodiplostomum revealed a lack of consistent morphological differences between the genera. Therefore, we consider Cheloniodiplostomum to be a junior synonym of Herpetodiplostomum. Recent molecular phylogenetic studies included a number of proterodiplostomid taxa; however, DNA sequence data are not available for any Herpetodiplostomum or Cheloniodiplostomum species. Herein, we describe a new Herpetodiplostomum species from Geoffroy's side-necked turtle Phrynops geoffroanus from Mato Grosso State, Brazil. The new species can be distinguished from other Herpetodiplostomum species based on the distribution of vitellarium, level of development of holdfast papillae, and ratio of prosoma:opisthosoma width, among other characters. We provide the first molecular phylogeny of the Proterodiplostomidae that includes a Herpetodiplostomum species. The limited geographic distribution of Herpetodiplostomum spp. within the geographic ranges of caimans suggests a secondary host switching event from crocodilians to chelonian definitive hosts in the evolution of Herpetodiplostomum.
Molecular and morphological description of the first Hepatozoon (Apicomplexa: Hepatozoidae) species infecting a neotropical turtle, with an approach to its phylogenetic relationships
Haemogregarines (Adeleorina) have a high prevalence in turtles. Nevertheless, there is only one Hepatozoon species described that infects Testudines so far; it is Hepatozoon fitzsimonsi which infects the African tortoise Kinixys belliana. Colombia harbours a great diversity of chelonians; however, most of them are threatened. It is important to identify and characterize chelonian haemoparasite infections to improve the clinical assessments, treatments and the conservation and reintroduction programs of these animals. To evaluate such infections for the Colombian wood turtle Rhinoclemmys melanosterna, we analysed blood from 70 individuals. By using the morphological characteristics of blood stages as well as molecular information (18S rRNA sequences), here we report a new Hepatozoon species that represents the first report of a hepatozoid species infecting a semi-aquatic continental turtle in the world. Although the isolated lineage clusters within the phylogenetic clades that have morphological species of parasites already determined, their low nodal support makes their position within each group inconclusive. It is important to identify new molecular markers to improve parasite species identification. In-depth research on blood parasites infecting turtles is essential for increasing knowledge that could assess this potential unknown threat, to inform the conservation of turtles and for increasing the state of knowledge on parasites.
First Record of a Polystome from Alligator Snapping Turtle, Macrochelys temminckii (Cryptodira: Chelydridae) or Mississippi; with Comments on “Neopolystoma orbiculare (Stunkard, 1916)” and Its Junior Subjective Synonyms
Herein, we describe several newly-collected specimens of Neopolystoma cf. orbiculare from the urinary bladder of 2 alligator snapping turtles, Macrochelys temminckii (Troost in Harland, 1835) (Cryptodira: Chelydridae Gray, 1831) from Comet Lake (30°35′46.94″N, 88°36′3.12″W), Pascagoula River, Mississippi. Our specimens differed from all previous descriptions of N. orbiculare and its junior subjective synonyms by the combination of having intestinal ceca adorned with triangular pockets and that terminate dorsal to the haptor, distinctive hooklets each having a handle and guard of approximately equal length and having a much longer and curved blade, 16 genital coronet spines that each possess 1–2 flanges per spine, pre-testicular vaginal pores, and vaginal ducts that are anterior to the junction of the oviduct and genito-intestinal canal. Some of our specimens were enantiomorphic (4 and 3 had a dextral and sinistral ovary, respectively). Nucleotide sequences (large subunit ribosomal DNA [28S], small subunit ribosomal DNA [18S], and cytochrome oxidase subunit 1 mitochondrial gene [COI]) for our specimens were most similar to GenBank sequences ascribed to N. orbiculare. Single-gene and concatenated phylogenetic analyses confirmed that NeopolystomaPrice, 1939 is polyphyletic and that our isolates share a recent common ancestor with those ascribed to N. orbiculare. This is the first record of a polystomatid from Mississippi, from the Pascagoula River, and from the alligator snapping turtle (and only the second species of Neopolystoma reported from any snapping turtle).
An extensive survey on helminth community of Caretta caretta from the neritic feeding grounds of Northwestern Adriatic sea
The opportunistic diet of loggerhead sea turtles, Caretta caretta , their long life-span and migratory behavior contribute to shaping the diversity of the gastrointestinal helminthic community. Heteroxenous helminths are also sentinels of marine environmental health, reflecting any perturbation of the trophic chain and, indirectly, of abiotic components of the ecosystem. With the aim of studying the helminth community of a top predator such as the loggerhead sea turtle C. caretta , parasites were collected from the digestive tract of 157 individuals, stranded dead along NW Adriatic Sea in the period 2009–2023, and morphologically identified. Prevalence, intensity, abundance, relative abundance and importance index were calculated for each taxon. Ontogenetic stages and sex of the hosts, seasons and observation periods were compared to unveil any difference in parasite community structure. Overall, richness and diversity were similar to other neritic grounds in the Mediterranean Sea; helminths from 9 species were recovered, with the trematode Rhytidodes gelatinosus and the nematode Sulcascaris sulcata having the highest importance. Prevalence, intensity and abundance of helminthiases increased significantly in the period 2015–2023. Helminthic community composition and richness generally overlap with what observed in other similar neritic areas, confirming the role of the ecosystem in shaping C. caretta gastrointestinal helminthic community. Increase in prevalence and intensity of helminthiases and composition of the parasitic community throughout the observation period suggests potential alterations within the Adriatic ecosystem in its biotic and/or abiotic components, potentially associated with underlying global climate change.
Assessment of Chlorella vulgaris as a biological control agent against tortoise tick Hyalomma aegyptium (Acari: Ixodidae) in Egypt
Hyalomma aegyptium is a three-host tick species parasitizing mainly tortoises in Asia, North Africa, and the Middle East. It serves as a carrier for various pathogenic bacteria and protozoa that pose threats to humans, wildlife, and domestic animals. Ticks control using chemical acaricides has negative effects to the environment and animal and human health, residues in animal products and leading to resistant ticks. So safe, eco-friendly, and cost-effective methods must be alternatively used. The green microalga Chlorella vulgaris is rich in proteins, lipids, carbohydrates and vitamins. It is used in biofuel production, wastewater treatment, and as a biofertilizer. It is used in pharmaceutical drugs with many beneficial characteristics. Examination of collected specimens in the present study ensured that they were identified as H. aegyptium nymphs. Using the powdering method, nymphs were treated with Chlorella and observed for 18 days. The results showed that the effect began 4 days after treatment, the mortality percentage reached 80%, and delayed molting period with only 20% molted into males. Morphological observations using light and scanning electron microscopes revealed a stiffened nymph body after treatment with a highly damaged capitulum, integument, and legs. Integument semithin sections showed thin, disorganized cuticle with damaged layers and destructed epidermal cells after treatment. No signs of new cuticle formation were noticed. The effect of Chlorella was either mechanical through powder particles or physiological through its effect on organs. This study may provide valuable information to help in the development of new methods to control ticks and/or improve the existing ones, allowing the creation of methods which do not induce resistance in ticks, and that are less toxic to the environment and non-target organisms.
Spatial distribution of epibionts on olive ridley sea turtles at Playa Ostional, Costa Rica
There is a wealth of published information on the epibiont communities of sea turtles, yet many of these studies have exclusively sampled epibionts found only on the carapace. Considering that epibionts may be found on almost all body-surfaces and that it is highly plausible to expect different regions of the body to host distinct epibiont taxa, there is a need for quantitative information on the spatial variation of epibiont communities on turtles. To achieve this, we measured how total epibiont abundance and biomass on olive ridley turtles Lepidochelys olivacea varies among four body-areas of the hosts (n = 30). We showed that epibiont loads on olive ridleys are higher, both in terms of number and biomass, on the skin than they are on the carapace or plastron. This contrasts with previous findings for other hard-shelled sea turtles, where epibionts are usually more abundant on the carapace or plastron. Moreover, the arguably most ubiquitous epibiont taxon for other hard-shelled sea turtles, the barnacle Chelonibia spp., only occurred in relatively low numbers on olive ridleys and the barnacles Stomatolepas elegans and Platylepas hexastylos are far more abundant. We postulate that these differences between the epibiont communities of different sea turtle taxa could indicate that the carapaces of olive ridley turtles provide a more challenging substratum for epibionts than do the hard shells of other sea turtles. In addition, we conclude that it is important to conduct full body surveys when attempting to produce a holistic qualitative or quantitative characterization of the epibiont communities of sea turtles.
Revision of the systematics of the Polystomoidinae (Platyhelminthes, Monogenea, Polystomatidae) with redefinition of Polystomoides Ward, 1917 and Uteropolystomoides Tinsley, 2017
Polystomatids are platyhelminth parasites that infect mainly amphibians and freshwater turtles. For more than seven decades, chelonian polystomes were classified into three genera according to the number of hamuli, i.e. absent for Neopolystoma , one pair for Polystomoidella and two pairs for Polystomoides . Following re-examination of morphological characters, seven new genera were erected the past six years, namely Apaloneotrema , Aussietrema , Fornixtrema , Manotrema , Pleurodirotrema , Uropolystomoides and Uteropolystomoides . However, the polyphyly of Neopolystoma and Polystomoides on the one hand, and the nested position of Uteropolystomoides within a clade encompassing all Neopolystom a and Polystomoides spp. on the other, still raised questions about the validity of these genera. We therefore re-examined several types, paratypes and voucher specimens, and investigated the molecular phylogeny of polystomes sampled from the oral cavity of North American turtles to re-evaluate their systematic status. We show that all Polystomoides Ward, 1917, sensu Du Preez et al., 2022, Neopolystoma Price, 1939, sensu Du Preez et al., 2022 and Uteropolystomoides Tinsley, 2017 species, display vaginae that are peripheral and extend well beyond the intestine. We thus reassign all species of the clade to Polystomoides and propose nine new combinations; however, although Uteropolystomoides is nested within this clade, based on its unique morphological features, we propose to keep it as a valid taxon. Polystomoides as redefined herein groups all polystome species infecting either the oral cavity or the urinary bladder of cryptodires, with peripheral vaginae and with or without two pairs of small hamuli. Uteropolystomoides nelsoni (Du Preez & Van Rooyen 2015), originally described from Pseudemys nelsoni Carr is now regarded as Uteropolystomoides multifalx (Stunkard, 1924) n. comb. infecting three distinct Pseudemys species of North America. Les Polystomatidés sont des plathelminthes parasites qui infestent principalement les amphibiens et les tortues d’eau douce. Pendant plus de sept décennies, les polystomes de chéloniens ont été classés en trois genres selon le nombre d’hamuli, absents pour Neopolystoma , une paire pour Polystomoidella et deux paires pour Polystomoides . Suite au réexamen des caractères morphologiques, sept nouveaux genres ont été érigés ces six dernières années, à savoir Apaloneotrema , Aussietrema , Fornixtrema , Manotrema , Pleurodirotrema , Uropolystomoides et Uteropolystomoides . Cependant, la polyphylie de Neopolystoma et Polystomoides d’une part, et la position imbriquée d’ Uteropolystomoides au sein d’un clade englobant toutes les espèces de Neopolystoma et Polystomoides d’autre part, soulèvent encore des questions sur la validité de ces trois genres. Nous avons donc réexaminé plusieurs types, paratypes et vouchers et étudié la phylogénie moléculaire de polystomes prélevés dans la cavité buccale de tortues d’Amérique du Nord pour réévaluer leur statut systématique. Nous montrons que toutes les espèces de Polystomoides Ward, 1917, sensu Du Preez et al., 2022, Neopolystoma Price, 1939, sensu Du Preez et al., 2022 et Uteropolystomoides Tinsley, 2017, présentent des vagins périphériques qui s’étendent bien au-delà de l’intestin. Nous réattribuons ainsi toutes les espèces du clade à Polystomoides et proposons neuf nouvelles combinaisons; cependant, nous proposons de conserver Uteropolystomoides sur la base de ses caractéristiques morphologiques exceptionnelles, bien que son espèce soit imbriquée au sein de ce clade. Polystomoides tel que redéfini ici regroupe toutes les espèces de polystomes infectant soit la cavité buccale, soit la vessie des cryptodires, avec des vagins périphériques, et deux paires de petits hamuli ou sans hamuli. Uteropolystomoides nelsoni (Du Preez & Van Rooyen 2015), l’unique espèce décrite à l’origine à partir de Pseudemys nelsoni Carr est maintenant considérée comme Uteropolystomoides multifalx (Stunkard, 1924) n. comb., qui infecte trois espèces distinctes de Pseudemys d’Amérique du Nord.