Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 34
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Mol Biol Rep ; 48(5): 4961-4965, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34145534

RESUMO

Anecdotal reports from fishers in Southeast Queensland, Australia suggest that shark depredation is a significant issue, however little is known about which species are responsible for depredating catches. This research aimed to identify depredating species in Southeast Queensland line based fisheries, by undertaking a genetic analysis of depredated samples collected by commercial, charter and recreational fishers. The genetic analysis successfully identified ten depredating sharks, all from the genus Carcharhinus (19.2% success). The species identified using mitochondrial DNA included five C. leucas (bull sharks), two C. plumbeus (sandbar sharks), one C. amboinensis (pigeye shark), one C. brevipinna (spinner shark) and one unconfirmed C. plumbeus/C. altimus (bignose shark). While many species of Carcharhinus have been found to depredate catches in Australia, C. leucas has not been highlighted until this research as a potential problematic species. The optimised protocol allowed for the confident identification of shark species responsible for depredation in fisheries using frozen fish samples donated by fishers.


Assuntos
Tubarões , Animais , Conservação dos Recursos Naturais , DNA Mitocondrial , Pesqueiros , Comportamento Predatório , Queensland , Tubarões/classificação , Tubarões/genética
2.
Appl Environ Microbiol ; 86(6)2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-31900308

RESUMO

The horn fly, Haematobia irritansirritans, is a hematophagous parasite of livestock distributed throughout Europe, Africa, Asia, and the Americas. Welfare losses on livestock due to horn fly infestation are estimated to cost between $1 billion and $2.5 billion (U.S. dollars) annually in North America and Brazil. The endosymbiotic bacterium Wolbachia pipientis is a maternally inherited manipulator of reproductive biology in arthropods and naturally infects laboratory colonies of horn flies from Kerrville, TX, and Alberta, Canada, but it has also been identified in wild-caught samples from Canada, the United States, Mexico, and Hungary. Reassembly of PacBio long-read and Illumina genomic DNA libraries from the Kerrville H. i. irritans genome project allowed for a complete and circularized 1.3-Mb Wolbachia genome (wIrr). Annotation of wIrr yielded 1,249 coding genes, 34 tRNAs, 3 rRNAs, and 5 prophage regions. Comparative genomics and whole-genome Bayesian evolutionary analysis of wIrr compared to published Wolbachia genomes suggested that wIrr is most closely related to and diverged from Wolbachia supergroup A strains known to infect Drosophila spp. Whole-genome synteny analyses between wIrr and closely related genomes indicated that wIrr has undergone significant genome rearrangements while maintaining high nucleotide identity. Comparative analysis of the cytoplasmic incompatibility (CI) genes of wIrr suggested two phylogenetically distinct CI loci and acquisition of another cifB homolog from phylogenetically distant supergroup A Wolbachia strains, suggesting horizontal acquisition of these loci. The wIrr genome provides a resource for future examination of the impact Wolbachia may have in both biocontrol and potential insecticide resistance of horn flies.IMPORTANCE Horn flies, Haematobia irritans irritans, are obligate hematophagous parasites of cattle having significant effects on production and animal welfare. Control of horn flies mainly relies on the use of insecticides, but issues with resistance have increased interest in development of alternative means of control. Wolbachia pipientis is an endosymbiont bacterium known to have a range of effects on host reproduction, such as induction of cytoplasmic incompatibility, feminization, male killing, and also impacts vector transmission. These characteristics of Wolbachia have been exploited in biological control approaches for a range of insect pests. Here we report the assembly and annotation of the circular genome of the Wolbachia strain of the Kerrville, TX, horn fly (wIrr). Annotation of wIrr suggests its unique features, including the horizontal acquisition of additional transcriptionally active cytoplasmic incompatibility loci. This study provides the foundation for future studies of Wolbachia-induced biological effects for control of horn flies.


Assuntos
Genes Bacterianos , Muscidae/microbiologia , Simbiose , Wolbachia/fisiologia , Animais , Transferência Genética Horizontal , Simbiose/genética , Wolbachia/genética
3.
Bull Entomol Res ; 110(6): 709-724, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32456717

RESUMO

The genus Megastigmus Dalman, 1820 (Hymenoptera: Megastigmidae) contains potential biocontrol agents of the invasive eucalypt galling chalcid Leptocybe spp. (Hymenoptera: Eulophidae), with several species reported in various parts of the world. Species discrimination is challenging due to intraspecific morphological variation, difficulty in measuring sizes of body parts, and the lack of information regarding the global distribution of parasitic Megastigmus. We used two species commonly associated with Leptocybe in its native range to review taxonomic methods and determine the most reliable morphological characters in species delimitation. We examined size variation of body characters, and conducted species discrimination using multivariate ratio analysis, mitochondrial Cytochrome c oxidase subunit 1 (COI) and nuclear 28S rDNA (28S) sequences. Morphological traits were effective in species delimitation yet revealed high variation in several characters employed in current keys. Knowledge generated on morphology and DNA justified the description of a new species, M. manonae, sp. n., the first record of M. pretorianensis in Australia, and revised diagnostic characters for M. zvimendeli. Based on these diagnostic characters and molecular data, we synonymize three species (M. judikingae, syn. n., from Australia, M. sichuanensis, syn. n., from China and M. icipeensis, syn. n., from Kenya) with M. zvimendeli. Our findings highlight the importance of molecular markers in assisting taxonomic decision-making and the need for coordinated work in identifying Megastigmus associated with Leptocybe spp.


Assuntos
Himenópteros/classificação , Himenópteros/genética , Animais , Austrália , Código de Barras de DNA Taxonômico , DNA Ribossômico/genética , Eucalyptus/parasitologia , Himenópteros/anatomia & histologia , Himenópteros/parasitologia , Especificidade da Espécie
4.
Folia Parasitol (Praha) ; 632016 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-27507709

RESUMO

Infective nymphal stages of the family Sebekidae Sambon, 1922 are reported from four species of fish in Australian waters for the first time. Infected fish were collected from locations in Western Australia, the Northern Territory and north Queensland. The infective nymphs of Alofia merki Giglioli in Sambon, 1922 and Sebekia purdieae Riley, Spratt et Winch, 1990 are reported and described for the first time. The remaining specimens were identified as belonging to the genus Sebekia Sambon, 1922 based on the combination of buccal cadre shape, shape and size of hooks, and overall body size, but could not be attributed to any of the other species of Sebekia already reported due to missing required morphological features. DNA sequences of members of the family Sebekidae are presented for the first time. The lack of knowledge on the pentastome fauna of wild crocodiles, and any potential intermediate hosts, in northern Australia, is also outlined.


Assuntos
Crustáceos/classificação , Peixes/parasitologia , Jacarés e Crocodilos/parasitologia , Animais , Austrália , Crustáceos/anatomia & histologia , Crustáceos/genética , Ninfa/fisiologia , Especificidade da Espécie
6.
Electrophoresis ; 35(4): 494-502, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24166785

RESUMO

Coccidiosis is a costly worldwide enteric disease of chickens caused by parasites of the genus Eimeria. At present, there are seven described species that occur globally and a further three undescribed, operational taxonomic units (OTUs X, Y, and Z) that are known to infect chickens from Australia. Species of Eimeria have both overlapping morphology and pathology and frequently occur as mixed-species infections. This makes definitive diagnosis with currently available tests difficult and, to date, there is no test for the detection of the three OTUs. This paper describes the development of a PCR-based assay that is capable of detecting all ten species of Eimeria, including OTUs X, Y, and Z in field samples. The assay is based on a single set of generic primers that amplifies a single diagnostic fragment from the mitochondrial genome of each species. This one-tube assay is simple, low-cost, and has the capacity to be high throughput. It will therefore be of great benefit to the poultry industry for Eimeria detection and control, and the confirmation of identity and purity of vaccine strains.


Assuntos
Galinhas/parasitologia , Coccidiose/diagnóstico , Eimeria/isolamento & purificação , Parasitologia/métodos , Animais , Coccidiose/parasitologia , Coccidiose/veterinária , Eimeria/genética , Eletroforese Capilar/métodos , Fezes/parasitologia , Oocistos , Reação em Cadeia da Polimerase/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
7.
Med Sci Educ ; 32(2): 503-509, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35194524

RESUMO

Training to become a clinical academic is a long and arduous process with many obstacles. Many potential candidates fall by the wayside both during and following completion of the combined clinical and academic training pathway with negative implications for clinical and translational research and teaching. Findings from a recent national multi-funder study, alongside clinical academic experiences and current literature, have led to the creation of this 12-tip paper. The tips are targeted at supervisors and employers of clinical academics, aiming to improve recruitment, experiences, retention, and progression through the career path.

8.
PLoS Pathog ; 5(5): e1000458, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19478871

RESUMO

The fungal disease chytridiomycosis, caused by Batrachochytrium dendrobatidis, is enigmatic because it occurs globally in both declining and apparently healthy (non-declining) amphibian populations. This distribution has fueled debate concerning whether, in sites where it has recently been found, the pathogen was introduced or is endemic. In this study, we addressed the molecular population genetics of a global collection of fungal strains from both declining and healthy amphibian populations using DNA sequence variation from 17 nuclear loci and a large fragment from the mitochondrial genome. We found a low rate of DNA polymorphism, with only two sequence alleles detected at each locus, but a high diversity of diploid genotypes. Half of the loci displayed an excess of heterozygous genotypes, consistent with a primarily clonal mode of reproduction. Despite the absence of obvious sex, genotypic diversity was high (44 unique genotypes out of 59 strains). We provide evidence that the observed genotypic variation can be generated by loss of heterozygosity through mitotic recombination. One strain isolated from a bullfrog possessed as much allelic diversity as the entire global sample, suggesting the current epidemic can be traced back to the outbreak of a single clonal lineage. These data are consistent with the current chytridiomycosis epidemic resulting from a novel pathogen undergoing a rapid and recent range expansion. The widespread occurrence of the same lineage in both healthy and declining populations suggests that the outcome of the disease is contingent on environmental factors and host resistance.


Assuntos
Anfíbios/microbiologia , Quitridiomicetos/genética , Animais , Sequência de Bases , DNA Viral , Surtos de Doenças , Genoma Mitocondrial , Genótipo , Perda de Heterozigosidade , Micoses , Polimorfismo Genético , Rana catesbeiana/microbiologia , Recombinação Genética
9.
Pathogens ; 10(9)2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34578243

RESUMO

BACKGROUND: Stephanofilaria spp. nematodes are associated with cutaneous lesions in cattle and other livestock and mammalian wildlife species. In Australia, Haematobia irritans exigua, commonly known as buffalo fly (BF) transmits a well-described but presently unnamed species of Stephanofilaria, which has been speculatively implicated in the aetiology of BF lesions. The sensitivity of current techniques for detecting Stephanofilaria spp. in skin lesions and vector species is low, and there is no genomic sequence for any member of the genus Stephanofilaria currently available in sequence databases. METHODS: To develop molecular assays for the detection of the Australian Stephanofilaria sp., skin biopsies were collected from freshly slaughtered cattle with typical lesions near the medial canthus. Adult nematodes and microfilariae were isolated from the biopsies using a saline recovery technique. The nematodes were morphologically identified as Stephanofilaria sp. by scanning electron microscopy. DNA was extracted and the internal transcribed spacer 2 (ITS2) region of rDNA, and the cytochrome c oxidase subunit 1 (cox1) region of mtDNA was amplified and sequenced. Stephanofilaria sp. specific polymerase chain reaction (PCR) and qPCR assays (SYBR Green® and TaqMan™) were developed and optimised from the novel ITS2 sequence obtained. The specificity of each assay was confirmed by testing against nematode species Onchocerca gibsoni and Dirofilaria immitis, as well as host (bovine) and BF DNA. RESULTS: Scanning electron microscopy of the anterior and posterior ends of isolated nematodes confirmed Stephanofilaria sp. A phylogenetic analysis of the cox1 sequence demonstrated that this species is most closely related to Thelazia callipaeda, a parasitic nematode that is a common cause of thelaziasis (or eyeworm infestation) in humans, dogs, and cats. Both conventional and qPCR assays specifically amplified DNA from Stephanofilaria sp. Conventional PCR, TaqMan™, and SYBR Green® assays were shown to detect 1 ng, 1 pg, and 100 fg of Stephanofilaria DNA, respectively. Both qPCR assays detected DNA from single Stephanofilaria microfilaria. CONCLUSION: Molecular diagnostic assays developed in this study showed high specificity and sensitivity for Stephanofilaria sp. DNA. The availability of an accurate and sensitive PCR assay for Stephanofilaria will assist in determining its role in the pathogenesis of cattle skin lesions, as well as in understanding its epidemiological dynamics. This assay may also have application for use in epidemiological studies with other species of Stephanofilaria, most particularly closely related S. stilesi, but this will require confirmation.

10.
Vet Parasitol ; 288: 109297, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33248417

RESUMO

Ectoparasites and livestock-associated insects are a major concern throughout the world because of their economic and welfare impacts. Effective control is challenging and relies mainly on the use of chemical insecticides and acaricides. Wolbachia, an arthropod and nematode-infecting, maternally-transmitted endosymbiont is currently of widespread interest for use in novel strategies for the control of a range of arthropod-vectored human diseases and plant pests but to date has received only limited consideration for use in the control of diseases of veterinary concern. Here, we review the currently available information on Wolbachia in veterinary ectoparasites and disease vectors, consider the feasibility for use of Wolbachia in the control of livestock pests and diseases and highlight critical issues which need further investigation.


Assuntos
Ectoparasitoses/veterinária , Gado , Wolbachia/fisiologia , Animais , Camelus/parasitologia , Bovinos/parasitologia , Cimicidae/microbiologia , Dípteros/microbiologia , Ectoparasitoses/parasitologia , Ectoparasitoses/prevenção & controle , Cabras/parasitologia , Cavalos/parasitologia , Ácaros/microbiologia , Ftirápteros/microbiologia , Carneiro Doméstico/parasitologia , Sifonápteros/microbiologia , Sus scrofa/parasitologia , Carrapatos/microbiologia
11.
Ecol Evol ; 10(20): 11565-11578, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33144984

RESUMO

Since outbreaks of the invasive blue gum chalcids Leptocybe spp. began, the genus Megastigmus (Hymenoptera: Megastigmidae) has been increasingly studied as containing potential biocontrol agents against these pests. Megastigmus species have been collected and described from Australia, the presumed origin of Leptocybe spp., with M. zvimendeli and M. lawsoni reported as Leptocybe spp. parasitoids established outside of Australia. Parasitic Megastigmus have been reported to occur locally in the Neotropics, Afrotropic, Palearctic, and Indomalaya biogeographic realms, and in many cases described as new to science. However, molecular tools have not been used in studying parasitic Megastigmus, and difficulties in morphological taxonomy have compromised further understanding of eucalypt-associated Megastigmus as well as the Megastigmus-Leptocybe association. In this study, we used molecular markers to study the species composition and phylogeny of Megastigmus collected from eucalypt galls in Australia and from Leptocybe spp. galls from South Africa, Kenya, Israel, China, and Vietnam. We record thirteen discrete species and a species complex associated with eucalypt galls. A summary of morphological characters is provided to assist morphological delimitation of the studied group. A phylogeny based on 28S rDNA identified species groups of importance to Leptocybe spp. biocontrol agents from four clades with nine species. Relationships between Megastigmus from eucalypt galls and their phytophagous congeners were unresolved. Further molecular work is needed to clarify the identity of many species.

12.
Pest Manag Sci ; 76(7): 2441-2452, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32058670

RESUMO

BACKGROUND: Haematobia spp., horn flies (HF) and buffalo flies (BF), are economically important ectoparasites of dairy and beef cattle. Control of these flies relies mainly on treating cattle with chemical insecticides. However, the development of resistance to commonly used compounds is compromising the effectiveness of these treatments and alternative methods of control are required. Wolbachia are maternally transmitted endosymbiotic bacteria of arthropods that cause various reproductive distortions and fitness effects, making them a potential candidate for use in the biological control of pests. The first step towards this is the establishment and adaptation of xenobiotic infections of Wolbachia in target host cell lines. RESULTS: Here, we report the successful establishment of a continuous HF cell line (HIE-18) from embryonic cells and its stable transinfection with Wolbachia strains wAlbB native to mosquitoes, and wMel and wMelPop native to Drosophila melanogaster. HIE-18 cells were typically round and diploid with ten chromosomes (2n = 10) or tetraploid with 20 chromosomes (4n = 20), with a doubling time of 67.2 h. Wolbachia density decreased significantly in HIE-18 cells in the first 48 h of infection, possibly due to overexpression of antimicrobial peptides through the Imd immune signalling pathway. However, density recovered after this time and HIE-18 cell lines stably infected with the three strains of Wolbachia have now each been subcultured more than 50 times as persistently infected lines. CONCLUSION: The amenability of HF cells to infection with different strains of Wolbachia and the establishment of stable sustaining infections suggest the potential for use of Wolbachia in novel approaches for the control of Haematobia spp. Further, the availability of the HIE-18 cell line will provide an important resource for the study of genetics, host-parasite interactions and chemical resistance in Haematobia populations. © 2020 Society of Chemical Industry.


Assuntos
Muscidae , Wolbachia , Animais , Linhagem Celular , Drosophila melanogaster , Inseticidas
13.
Parasit Vectors ; 13(1): 296, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32522243

RESUMO

BACKGROUND: Buffalo flies (Haematobia irritans exigua) (BF) and closely related horn flies (Haematobia irritans irritans) (HF) are invasive haematophagous parasites with significant economic and welfare impacts on cattle production. Wolbachia are intracellular bacteria found widely in insects and currently of much interest for use in novel strategies for the area wide control of insect pests and insect-vectored diseases. In this paper, we report the transinfection of BF towards the development of area-wide controls. METHODS: Three stages of BF; embryos, pupae and adult female flies, were injected with different Wolbachia strains (wAlbB, wMel and wMelPop). The success of transinfection and infection dynamics was compared by real-time PCR and FISH and fitness effects were assessed in transinfected flies. RESULTS: BF eggs were not easily injected because of their tough outer chorion and embryos were frequently damaged with less than 1% hatch rate of microinjected eggs. No Wolbachia infection was recorded in flies successfully reared from injected eggs. Adult and pupal injection resulted in higher survival rates and somatic and germinal tissue infections, with transmission to the succeeding generations on some occasions. Investigations of infection dynamics in flies from injected pupae confirmed that Wolbachia were actively multiplying in somatic tissues. Ovarian infections were confirmed with wMel and wMelPop in a number of instances, though not with wAlbB. Measurement of fitness traits indicated reduced longevity, decreased and delayed adult emergence, and reduced fecundity in Wolbachia-infected flies compared to mock-injected flies. Effects varied with the Wolbachia strain injected with most marked changes seen in the wMelPop-injected flies and least severe effects seen with wAlbB. CONCLUSIONS: Adult and pupal injection were the most suitable methods for transinfecting BF and all three strains of Wolbachia successfully replicated in somatic tissues. The Wolbachia-induced fitness effects seen in transinfected BF suggest potential for use of the wMel or wMelPop strains in Wolbachia-based biocontrol programmes for BF.


Assuntos
Muscidae/microbiologia , Controle Biológico de Vetores/métodos , Wolbachia/fisiologia , Animais , Feminino , Fertilidade , Interações entre Hospedeiro e Microrganismos , Estágios do Ciclo de Vida , Longevidade , Masculino , Microinjeções , Wolbachia/genética
15.
BMJ Paediatr Open ; 3(1): e000398, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30957027

RESUMO

BACKGROUND: This study reports how parents and young people who had an experience offebrile neutropenia (FN) improved the design of a trial to inform the management of this condition. Five parents, a young person who had completed treatment and three clinician-researchers contributed. METHODS: The group was formed after an invitation on social media and met via video conference. Many participants were from an existing childhood-cancer parent-involvement group. The initial questions asked during discussion were about the importance of the topic, the views on the need for a trial, which important outcomes should be measured and the practical aspects which would make it easier or more difficult for people to take part in it. The conversation occurred for an entire afternoon, was audio and video recorded, transcribed, analysed and checked by those involved. The fifth parent added to this via email. RESULTS: The group altered the trial structure by proposing randomising of each child to one of the two management methods through the whole of their anti-cancer treatment, rather than randomising the study sites or the child at each visit. They felt that even if people declined taking part in the study in the first weeks of diagnosis, their views might change and they should be allowed to consent later. They also proposed methods of collecting important patient and family data, enriching the medical information gained in the study. Active follow-up, negotiated for each individual family, was also suggested. CONCLUSION: Trials for improving the management of FN in children and young people who are undergoing anti-cancer treatments should consider individual-patient randomisation, collection of 'quality of life' and 'experience of care' aspects using digital and paper-based methods, engage families in shared decision-making about management options and ensure adequate supportive information is available and accessible to all patients regardless of background, geographical location or age.

16.
Syst Rev ; 8(1): 82, 2019 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-30944024

RESUMO

BACKGROUND: Fever and neutropenia (FN) is a common complication of chemotherapy for cancer. Prompt empiric broad-spectrum antibiotic therapy in FN is typically considered standard of care, but the definition of prompt is not clear. We seek to systematically review the available data on the association between time to antibiotics (TTA) administration and clinical outcomes in patients with FN being treated with chemotherapy. There have been several efforts to reduce TTA in patients with FN, by implementing specific interventions, presuming there will be a beneficial effect on patient-important outcomes. This systematic review will also collect data on such interventions and their effect to reduce TTA and potentially change clinical outcomes. METHODS/DESIGN: The search will cover MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, CINAHL, CDSR, CENTRAL, and LILACS. A full-search strategy is provided. Lists of studies identified by references cited and forward citation searching of included articles will also be reviewed. Studies will be screened, and data extracted by one researcher and independently checked by a second. Confounding biases and quality of studies will be assessed with the risk of bias in non-randomised studies-of interventions (ROBINS-I) tool. Data will be presented in narrative and tabular forms; in addition, if appropriate data is available, random effects meta-analysis will be used to examine TTA. A detailed analysis plan, including an assessment of heterogeneity and publication bias, is provided. DISCUSSION: This study aims to evaluate the association between TTA and patient-important clinical outcomes. Additionally, it will identify, critically appraise, and synthesise information on performed interventions and its effect to reduce TTA as a way of gaining insight into the potential use of these approaches. This will provide better knowledge for an adjusted treatment approach of FN. SYSTEMATIC REVIEW REGISTRATION: PROSPERO [ CRD42018092948 ].


Assuntos
Antineoplásicos/uso terapêutico , Febre/tratamento farmacológico , Neoplasias/tratamento farmacológico , Neutropenia/tratamento farmacológico , Antibacterianos/uso terapêutico , Antineoplásicos/efeitos adversos , Febre/diagnóstico , Humanos , Neoplasias/complicações , Neutropenia/diagnóstico , Fatores de Tempo , Revisões Sistemáticas como Assunto
17.
J Parasitol ; 104(2): 117-132, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29231789

RESUMO

Adult and cystacanth forms of the acanthocephalan Serrasentis sagittifer from Australian coastal waters are redescribed and verified as the same species using both molecular and morphological data. This study provides the baseline 18S rDNA, 28S rDNA, and cox1 sequence data to serve as genetic barcode for S. sagittifer. The validity of the currently recognized species of Serrasentis is discussed. The most recently described species are junior synonyms of either Serrasentis nadakali or S. sagittifer, and a number of species are species inquirenda. When using morphological characters to distinguish the species of Serrasentis, consideration needs to be given to the maturity of the specimens, since the trunk elongates and the number and distribution of the ventral combs changes as worms mature, although the proboscis armature itself does not change. A simple key to assist in the identification of species of Serrasentis is provided. Adult S. sagittifer appear to be highly host specific to the cobia, Rachycentron canadum, in northern Australian waters, whereas cystacanths have been reported from a wide range of fish species. The relationship between host length and number of cystacanths shows that most paratenic infections are acquired as young fish, most likely via a crustacean intermediate host.


Assuntos
Acantocéfalos/anatomia & histologia , Acantocéfalos/classificação , Doenças dos Peixes/parasitologia , Helmintíase Animal/parasitologia , Acantocéfalos/genética , Acantocéfalos/crescimento & desenvolvimento , Animais , Austrália , Sequência de Bases , Sequência Consenso , DNA de Helmintos/química , DNA de Helmintos/isolamento & purificação , DNA Ribossômico/química , Feminino , Peixes , Interações Hospedeiro-Parasita , Oceano Índico , Funções Verossimilhança , Masculino , Oceano Pacífico , Filogenia , Alinhamento de Sequência
18.
Vet Parasitol ; 243: 58-66, 2017 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-28807311

RESUMO

Modern molecular approaches have vastly improved diagnostic capabilities for differentiating among species of chicken infecting Eimeria. Consolidating information from multiple genetic markers, adding additional poultry Eimeria species and increasing the size of available data-sets is improving the resolving power of the DNA, and consequently our understanding of the genus. This study adds information from 25 complete mitochondrial DNA genomes from Australian chicken Eimeria isolates representing all 10 species known to occur in Australia, including OTU-X, -Y and -Z. The resulting phylogeny provides a comprehensive view of species relatedness highlighting where the OTUs align with respect to others members of the genus. All three OTUs fall within the Eimeria clade that contains only chicken-infecting species with close affinities to E. maxima, E. brunetti and E. mitis. Mitochondrial genetic diversity was low among Australian isolates likely reflecting their recent introduction to the country post-European settlement. The lack of observed genetic diversity is a promising outcome as it suggests that the currently used live vaccines should continue to offer widespread protection against Eimeria outbreaks in all states and territories. Flocks were frequently found to host multiple strains of the same species, a factor that should be considered when studying disease epidemiology in the field.


Assuntos
Galinhas/parasitologia , Coccidiose/veterinária , Eimeria/genética , Variação Genética , Genoma Mitocondrial/genética , Doenças das Aves Domésticas/parasitologia , Animais , Austrália/epidemiologia , Coccidiose/epidemiologia , Coccidiose/parasitologia , Eimeria/classificação , Eimeria/isolamento & purificação , Filogenia , Doenças das Aves Domésticas/epidemiologia
19.
Ecology ; 87(7): 1671-83, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16922318

RESUMO

A newly discovered infectious disease of amphibians, chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis, is implicated in population declines and possible extinctions throughout the world. The purpose of our study was to examine the effects of B. dendrobatidis on the mountain yellow-legged frog (Rana muscosa) in the Sierra Nevada of California (USA). We (1) quantified the prevalence and incidence of B. dendrobatidis through repeat surveys of several hundred R. muscosa populations in the southern Sierra Nevada; (2) described the population-level effects of B. dendrobatidis on R. muscosa population abundance; and (3) compared the mortality rates of infected and uninfected R. muscosa individuals from pre- through post-metamorphosis using both laboratory and field experiments. Mouthpart inspections conducted in 144 and 132 R. muscosa populations in 2003 and 2004, respectively, indicated that 19% of R. muscosa populations in both years showed indications of chytridiomycosis. Sixteen percent of populations that were uninfected in 2003 became infected by 2004. Rana muscosa population sizes were reduced by an average of 88% following B. dendrobatidis outbreaks at six sites, but at seven B. dendrobatidis-negative sites, R. muscosa population sizes increased by an average of 45% over the same time period. In the laboratory, all infected R. muscosa developed fatal chytridiomycosis after metamorphosis, while all uninfected individuals remained healthy. In the field experiment in which R. muscosa tadpoles were caged at infected and uninfected sites, 96% of the individuals that metamorphosed at infected sites died vs. 5% at the uninfected sites. These studies indicate that chytridiomycosis causes high mortality in post-metamorphic R. muscosa, that this emerging disease is the proximate cause of numerous observed R. muscosa population declines, and that the disease threatens this species with extirpation at numerous sites in California's Sierra Nevada.


Assuntos
Doenças dos Animais/microbiologia , Fungos/isolamento & purificação , Micoses/veterinária , Ranidae/microbiologia , Doenças dos Animais/epidemiologia , Animais , Incidência , Larva/microbiologia , Prevalência , Fatores de Tempo
20.
J Parasitol ; 92(1): 77-88, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16629320

RESUMO

Revealing diversity among extant blood flukes, and the patterns of relationships among them, has been hindered by the difficulty of determining if specimens described from different life cycle stages, hosts, geographic localities, and times represent the same or different species. Persistent collection of all available life cycle stages and provision of exact collection localities, host identification, reference DNA sequences for the parasite, and voucher specimens eventually will provide the framework needed to piece together individual life cycles and facilitate reconciliation with classical taxonomic descriptions, including those based on single life cycle stages. It also provides a means to document unique or rare species that might only ever be recovered from a single life cycle stage. With an emphasis on the value of new information from field collections of any available life cycle stages, here we provide data for several blood fluke cercariae from freshwater snails from Kenya, Uganda, and Australia. Similar data are provided for adult worms of Macrobilharzia macrobilharzia and miracidia of Bivitellobilharzia nairi. Some schistosome and sanguinicolid cercariae that we recovered have peculiar morphological features, and our phylogenetic analyses (18S and 28S rDNA and mtDNA CO1) suggest that 2 of the new schistosome specimens likely represent previously unknown lineages. Our results also provide new insights into 2 of the 4 remaining schistosome genera yet to be extensively characterized with respect to their position in molecular phylogenies, Macrobilharzia and Bivitellobilharzia. The accessibility of each life cycle stage is likely to vary dramatically from one parasite species to the next, and our examples validate the potential usefulness of information gleaned from even one such stage, whatever it might be.


Assuntos
Complexo IV da Cadeia de Transporte de Elétrons/genética , Estágios do Ciclo de Vida/genética , RNA Ribossômico 18S/genética , RNA Ribossômico 28S/genética , Schistosomatidae/classificação , Schistosomatidae/genética , Animais , Biodiversidade , Tamanho Corporal , DNA de Helmintos/química , Água Doce , Variação Genética , Funções Verossimilhança , Dados de Sequência Molecular , Filogenia , Schistosomatidae/ultraestrutura , Caramujos/parasitologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA