The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
P C Mills - One of the best experts on this subject based on the ideXlab platform.
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molecular characterization of Coccidia associated with an epizootic in green sea turtles chelonia mydas in south east queensland australia
PLOS ONE, 2016Co-Authors: Phoebe A Chapman, Helen Owen, Mark Flint, Rebecca J Traub, Thomas H Cribb, P C MillsAbstract:In the spring of 2014, mass mortalities among wild green sea turtles occurred off the coast of south-east Queensland, Australia. The suspected causative agent was Caryospora cheloniae, an eimeriid Coccidian implicated in previous epizootics. Necropsies were undertaken on a subset of 11 dead turtles, with subsequent histopathology and molecular analyses. All turtles returned positive PCR results for Coccidial infection in various tissues; these included the brain, gastrointestinal tract, lung, kidney and thyroid. Granulomatous encephalitis was consistently observed, as well as enteritis and, less frequently, thyroiditis and nephritis. Sequencing and phylogenetic analyses indicated the presence of two distinct Coccidian genotypes, presumably separate species—one associated with the brain, gastrointestinal tract and lung, and the second with the thyroid and kidney. Maximum likelihood and Bayesian inference analyses placed the first genotype closest to the lankesterellid genus Schellackia, rather than in the Eimeriidae, while the second was paraphyletic to the eimeriids. Presence of Coccidial stages in extra-intestinal tissues of the primary host raises questions about the potential presence of intermediate or paratenic hosts within the life cycles, as well as their current placement relative to the genus Caryospora. This study represents the first genetic characterization of this emerging disease agent in green sea turtles, an endangered species, and has relevance for life-cycle elucidation and future development of diagnostics.
R B Williams - One of the best experts on this subject based on the ideXlab platform.
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tracing the emergence of drug resistance in Coccidia eimeria spp of commercial broiler flocks medicated with decoquinate for the first time in the united kingdom
Veterinary Parasitology, 2006Co-Authors: R B WilliamsAbstract:Abstract Decoquinate is a quinolone coccidiostat introduced during 1967 as an in-feed prophylactic for broiler chickens. Despite early drug-resistance problems and its age, the drug is still used commercially worldwide. Decoquinate here serves as a valuable model in a field study that addresses the dynamics and economic impact of the development of Coccidial resistance to potent synthetic antiCoccidial drugs. The results of this unique, hitherto unpublished, study on the initial emergence of resistance of avian Coccidia (Eimeria spp.) to a new drug in the field may be of strategic value in the continued use of decoquinate or the introduction of new drugs. The commercial performance of the first 3–5 crops of broilers to be medicated with decoquinate on each of six farms was monitored during 14 months in 1968–1969, supplemented by assessments of the species, population dynamics and decoquinate-resistance of Coccidia isolated from each farm. During the rearing of each flock in a single shed on each farm, oocysts were counted in fresh faecal samples collected on three occasions, and the species were identified by their morphology if possible, supported if necessary by the biological characteristics of infections in chickens. E. acervulina was the most common species, followed by E. mitis, E. maxima, E. tenella and E. praecox. E. brunetti occurred rarely, and E. necatrix was not found. Decoquinate-resistance was evident in several species during the rearing of the first decoquinate-medicated crop on each farm, although clinical coccidiosis did not occur. It was concluded that inherently resistant mutants of E. acervulina, E. brunetti, E. maxima, E. tenella, and probably also E. mitis and E. praecox, were selected from field populations by 6 weeks during their first exposure to decoquinate. During up to four more subsequent crops, cycling of resistant parasites stimulated host immunity, which had no obvious adverse impact on commercial performance. There was no apparent seasonal effect. A hypothesis is proposed to explain the sudden and rapid emergence of quinolone-resistance in the Coccidia, and why bird health was not thereby compromised in these circumstances.
Mark Flint - One of the best experts on this subject based on the ideXlab platform.
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molecular characterization of Coccidia associated with an epizootic in green sea turtles chelonia mydas in south east queensland australia
PLOS ONE, 2016Co-Authors: Phoebe A Chapman, Helen Owen, Mark Flint, Rebecca J Traub, Thomas H Cribb, P C MillsAbstract:In the spring of 2014, mass mortalities among wild green sea turtles occurred off the coast of south-east Queensland, Australia. The suspected causative agent was Caryospora cheloniae, an eimeriid Coccidian implicated in previous epizootics. Necropsies were undertaken on a subset of 11 dead turtles, with subsequent histopathology and molecular analyses. All turtles returned positive PCR results for Coccidial infection in various tissues; these included the brain, gastrointestinal tract, lung, kidney and thyroid. Granulomatous encephalitis was consistently observed, as well as enteritis and, less frequently, thyroiditis and nephritis. Sequencing and phylogenetic analyses indicated the presence of two distinct Coccidian genotypes, presumably separate species—one associated with the brain, gastrointestinal tract and lung, and the second with the thyroid and kidney. Maximum likelihood and Bayesian inference analyses placed the first genotype closest to the lankesterellid genus Schellackia, rather than in the Eimeriidae, while the second was paraphyletic to the eimeriids. Presence of Coccidial stages in extra-intestinal tissues of the primary host raises questions about the potential presence of intermediate or paratenic hosts within the life cycles, as well as their current placement relative to the genus Caryospora. This study represents the first genetic characterization of this emerging disease agent in green sea turtles, an endangered species, and has relevance for life-cycle elucidation and future development of diagnostics.
Phoebe A Chapman - One of the best experts on this subject based on the ideXlab platform.
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caryospora like Coccidia infecting green turtles chelonia mydas an emerging disease with evidence of interoceanic dissemination
Frontiers in Veterinary Science, 2019Co-Authors: Brian A Stacy, James F X Wellehan, Phoebe A Chapman, Heather Stockdalewalden, Thierry M Work, Julie Dagenais, Allen M Foley, Morgan Wideroff, April L Childress, Charles A ManireAbstract:Protozoa morphologically consistent with Caryospora sp. are one of the few pathogens associated with episodic mass mortality events involving free-ranging sea turtles. Parasitism of green turtles (Chelonia mydas) by these Coccidia and associated mortality was first reported in maricultured turtles in the Caribbean during the 1970s. Years later, epizootics affecting wild green turtles in Australia occurred in 1991 and 2014. The first clinical cases of Caryospora-like infections reported elsewhere in free-ranging turtles were from the southeastern US in 2012. Following these initial individual cases in this region, we documented an epizootic and mass mortality of green turtles along the Atlantic coast of southern Florida from November 2014 through April 2015 and continued to detect additional, sporadic cases in the southeastern US in subsequent years. No cases of Coccidial disease were recorded in the southeastern US prior to 2012 despite clinical evaluation and necropsy of stranded sea turtles in this region since the 1980s, suggesting that the frequency of clinical coccidiosis has increased here. Moreover, we also recorded the first stranding associated with infection by a Caryospora-like organism in Hawai'i in 2018. To further characterize the Coccidia, we sequenced part of the 18S ribosomal and mitochondrial cytochrome oxidase I genes of Coccidia collected from 62 green turtles found in the southeastern US and from one green turtle found in Hawai'i. We also sequenced the ribosomal internal transcribed spacer regions from selected cases and compared all results with those obtained from Caryospora-like Coccidia collected from green turtles found in Australia. Eight distinct genotypes were represented in green turtles from the southeastern US. One genotype predominated and was identical to that of Coccidia collected from the green turtle found in Hawai'i. We also found a Coccidian genotype in green turtles from Florida and Australia with identical 18S and mitochondrial sequences, and only slight inter-regional differences in the internal transcribed spacer 2. We found no evidence of geographical structuring based on phylogenetic analysis. Low genetic variability among the Coccidia found in green turtle populations with minimal natural connectivity suggests recent interoceanic dissemination of these parasites, which could pose a risk to sea turtle populations.
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molecular characterization of Coccidia associated with an epizootic in green sea turtles chelonia mydas in south east queensland australia
PLOS ONE, 2016Co-Authors: Phoebe A Chapman, Helen Owen, Mark Flint, Rebecca J Traub, Thomas H Cribb, P C MillsAbstract:In the spring of 2014, mass mortalities among wild green sea turtles occurred off the coast of south-east Queensland, Australia. The suspected causative agent was Caryospora cheloniae, an eimeriid Coccidian implicated in previous epizootics. Necropsies were undertaken on a subset of 11 dead turtles, with subsequent histopathology and molecular analyses. All turtles returned positive PCR results for Coccidial infection in various tissues; these included the brain, gastrointestinal tract, lung, kidney and thyroid. Granulomatous encephalitis was consistently observed, as well as enteritis and, less frequently, thyroiditis and nephritis. Sequencing and phylogenetic analyses indicated the presence of two distinct Coccidian genotypes, presumably separate species—one associated with the brain, gastrointestinal tract and lung, and the second with the thyroid and kidney. Maximum likelihood and Bayesian inference analyses placed the first genotype closest to the lankesterellid genus Schellackia, rather than in the Eimeriidae, while the second was paraphyletic to the eimeriids. Presence of Coccidial stages in extra-intestinal tissues of the primary host raises questions about the potential presence of intermediate or paratenic hosts within the life cycles, as well as their current placement relative to the genus Caryospora. This study represents the first genetic characterization of this emerging disease agent in green sea turtles, an endangered species, and has relevance for life-cycle elucidation and future development of diagnostics.
David Modrý - One of the best experts on this subject based on the ideXlab platform.
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new species of choleoeimeria apicomplexa eimeriidae from the veiled chameleon chamaeleo calyptratus sauria chamaeleonidae with taxonomic revision of eimerian Coccidia from chameleons
Folia Parasitologica, 2006Co-Authors: Michal Sloboda, David ModrýAbstract:Coprological examination of 71 samples from a breeding colony of veiled chameleons, Chamaeleo calyptratus Dumeril et Dumeril, 1851, revealed a presence of two species of Coccidia. In 100% of the samples examined, oocysts of Isospora jaracimrmani Modrý et Koudela, 1995 were detected. A new Coccidian species, Choleoeimeria hirbayah sp. n., was discovered in 32.4% of samples from the colony. Its oocysts are tetrasporocystic, cylindrical, 28.3 (25-30) × 14.8 (13.5-17.5) µm, with smooth, bilayered, ~1 µm thick wall. Sporocysts are dizoic, ovoidal to ellipsoidal, 10.1 (9-11) × 6.9 (6-7.5) µm, sporocyst wall is composed of two plates joined by a meridional suture. Endogenous development is confined to the epithelium of the gall blad- der, with infected cells being typically displaced from the epithelium layer towards lumen. A taxonomic revision of tetrasporo- cystic Coccidia in the Chamaeleonidae is provided.
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three new species of Coccidia apicomplexa eimeriorina from the marble throated skink marmorosphax tricolor bavay 1869 reptilia scincidae endemic to new caledonia with a taxonomic revision of eimeria spp from scincid hosts
Parasitology Research, 2006Co-Authors: David Modrý, M JirkůAbstract:Three new species of Coccidia are described from Marble-throated skink Marmorosphax tricolor from New Caledonia, namely, Isospora bocagei sp. n., Acroeimeria rouxi sp. n., and Choleoeimeria sadlieri sp.n. All species differ markedly from other eimerian Coccidia described from scincid hosts. Isospora marmorosphaxi develops extra-nuclearly in small intestine. A. rouxi develops epicitoplasmatically in small intestine. C. sadlieri affects the gall bladder mucosa. Generic affiliation of Eimeria-like Coccidia from reptiles is discussed and all taxa (with adequate information on endogenous development available) from scincid hosts are revised and placed into genera Acroeimeria and Choleoeimeria.
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evolutionary relationships among cyst forming Coccidia sarcocystis spp alveolata apicomplexa coccidea in endemic african tree vipers and perspective for evolution of heteroxenous life cycle
Molecular Phylogenetics and Evolution, 2003Co-Authors: Jan Slapeta, David Modrý, Milan Jirků, Julius Lukes, Jan Votýpka, Břetislav KoudelaAbstract:Cyst-forming Coccidia of the genus Sarcocystis (Alveolata: Apicomplexa: Coccidea) parasitize vertebrates worldwide. Data from the small subunit rRNA genes (SSU) and the D2 domain of the large subunit rRNA genes were used to reconstruct phylogeny for all species in the Sarcocystidae for which sequences are currently available. We have focused on the evolutionary history of species that circulate between snakes as definitive hosts and rodents as intermediate hosts. Trees were reconstructed using maximum parsimony, minimum evolution, maximum likelihood and the bayesian phylogenetics. Our reconstructions support monophyly of Sarcocystidae but fail to robustly resolve the relationship within clades. Using a concatenated dataset of available rDNAs, the “isosporoid” Coccidia Neospora, Toxoplasma, Besnoitia, Isospora and Hyaloklossia form a sister group to the monophyletic Sarcocystis. Moreover, we show that Sarcocystis from arboreal vipers of the genus Atheris, which are endemic to the mountain rain forests of the Equatorial Africa, are monophyletic, with sister species parasitizing the desert viper Pseudocerastes persicus from the Near East. We report the co-evolution of Sarcocystis spp. with their final snake hosts. The geological history of the African continent, mountain ranges, forests and general SSU rDNA rates were used to construct a linearized tree. Possible origin of the heteroxenous life cycle of Sarcocystis is discussed.
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the phylogeny of goussia and choleoeimeria apicomplexa eimeriorina and the evolution of excystation structures in Coccidia
Protist, 2002Co-Authors: Milan Jirků, David Modrý, Jan Slapeta, Břetislav Koudela, Julius LukesAbstract:Summary The phylogenetic relationships of Goussia janae and Choleoeimeria sp. were analyzed using the small subunit ribosomal RNA gene (SSU rDNA). This is a first attempt to study the molecular phylogeny of Coccidian genera parasitizing strictly poikilotherm hosts. The biliary Eimeria -like Coccidia of reptiles classified into the genus Choleoeimeria form a sister clade to the family Eimeriidae, which confirms the separate generic status of the genus Choleoeimeria . The position of Goussia is less robustly resolved, since it forms a trichotomy with the Eimeriidae and Sarcocystidae, or alternatively constitutes the earliest branch of the Coccidian lineage. Morphological similarities, namely the extracytoplasmic location of the endogenous stages, and the presence of sutures in the sporocyst wall are discussed in the context of the traditional classification of eimeriids. In contrast to the morphology-based systematics, the monophyly of Goussia and Choleoeimeria is not supported by the SSU rDNA data.