Twenty Years of Equine Piroplasmosis Research: Global Distribution, Molecular Diagnosis, and Phylogeny.
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ABSTRACT:
SUBMITTER: Tirosh-Levy S
PROVIDER: S-EPMC7695325 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND:Equine piroplasmosis (EP) is an economically significant infection of horses and other equine species caused by the tick-borne protozoa Theileria equi and Babesia caballi. The long-term carrier state in infected animals makes importation of such subclinical cases a major risk factor for the introduction of EP into non-enzootic areas. Regulatory testing for EP relies on screening of equines by serological methods. The definitive diagnosis of EP infection in individual animals will benefit from the availability of sensitive direct detection methods, for example, when used as confirmatory assays for non-negative serological test results. The objectives of this study were to develop a real-time quantitative polymerase chain reaction (qPCR) assay for simultaneous detection of both agents of EP, perform comprehensive evaluation of its performance and assess the assay's utility for regulatory testing. RESULTS:We developed a duplex qPCR targeting the ema-1 gene of T. equi and the 18S rRNA gene of B. caballi and demonstrated that the assay has high analytical sensitivities for both piroplasm species. Validation of the duplex qPCR on samples from 362 competitive enzyme-linked immunosorbent assay (cELISA)-negative horses from Canada and the United States yielded no false-positive reactions. The assay's performance was further evaluated using samples collected from 430 horses of unknown EP status from a highly endemic area in Brazil. This set of samples was also tested by a single-target 18S rRNA qPCR for T. equi developed at the OIE reference laboratory for EP in Japan, and a previously published single-target 18S rRNA qPCR for B. caballi whose oligonucleotides we adopted for use in the duplex qPCR. Matching serum samples were tested for antibodies to these parasites using cELISA. By the duplex qPCR, T. equi-specific 18S rRNA qPCR and cELISA, infections with T. equi were detected in 87.9% (95% confidence interval, CI: 84.5-90.7%), 90.5% (95% CI: 87.3-92.3%) and 87.4% (95% CI: 84.0-90.2%) of the horses, respectively. The B. caballi prevalence estimates were 9.3% (95% CI: 6.9-12.4%) by the duplex qPCR and 7.9% (95% CI: 5.7-10.9%) by the respective single-target qPCR assay. These values were markedly lower compared to the seroprevalence of 58.6% (95% CI: 53.9-63.2%) obtained by B. caballi-specific cELISA. The relative diagnostic sensitivity of the duplex qPCR for T. equi was 95.5%, as 359 of the 376 horses with exposure to T. equi confirmed by cELISA had parasitemia levels above the detection limit of the molecular assay. In contrast, only 39 (15.5%) of the 252 horses with detectable B. caballi-specific antibodies were positive for this piroplasm species by the duplex qPCR. CONCLUSIONS:The duplex qPCR described here performed comparably to the existing single-target qPCR assays for T. equi and B. caballi and will be more cost-effective in terms of results turnaround time and reagent costs when both pathogens are being targeted for disease control and epidemiological investigations. These validation data also support the reliability of the ema-1 gene-specific oligonucleotides developed in this study for confirmatory testing of non-negative serological test results for T. equi by qPCR. However, the B. caballi-specific qPCR cannot be similarly recommended as a confirmatory assay for routine regulatory testing due to the low level of agreement with serological test results demonstrated in this study. Further studies are needed to determine the transmission risk posed by PCR-negative equines with detectable antibodies to B. caballi.
| S-EPMC5834856 | biostudies-literature
Project description:Equine piroplasmosis (EP) is a severe disease of horses caused by the tick-borne protozoa Theileria equi (T. equi) and Babesia caballi (B. caballi). Infectious carriers are not always symptomatic, meaning there is a risk to non-enzootic areas. Regulatory tests for EP include sero-epidemiological methods for equine babesiosis, but these lack specificity due to cross-reactivity with other Babesia species. In this study, we present a real-time quantitative recombinase polymerase amplification (qRPA) method for fast simultaneous detection of both T. equi and B. caballi. In this method, primers and probes targeting the 18S rRNA gene of both T. equi and B. caballi, the ema-1 gene of T. equi and the bc48 gene of B. caballi were designed and evaluated. The sensitivity of qRPA was evaluated using the pUC57 plasmid DNA containing the target gene. For the pUC57-bc48 gene DNA, the R2 value was 0.983 for the concentration range 0.2 ng (4.1 × 107 DNA copies) to 2.0 fg (4.1 × 101 DNA copies). For the pUC57-ema gene DNA, the R2 value was 0.993 for the concentration range 0.2 ng (5.26 × 107 DNA copies) to 2.0 fg (5.26 × 102 DNA copies). For the pUC57-Bc18S gene DNA the R2 value was 0.976 for the concentration range 2.0 ng (4.21 × 108 DNA copies) to 2.0 fg (4.21 × 102 DNA copies). For the pUC57-Te18S gene DNA, the R2 value was 0.952 (Fig. S3b) for the concentration range 2.0 ng (4.16 × 108 DNA copies) to 2.0 fg (4.16 × 102 DNA copies). Furthermore, a duplex qRPA analysis was developed and optimized and the results showed that primers and probes targeting for the bc48 gene of B. caballi and the 18S rRNA gene of T. equi is the best combination for a duplex qRPA analysis in one reaction. The developed duplex qRPA assay has good specificity, and had negative amplification for several similar parasite. For DNA extracted from real horse blood specimens, this qRPA method has comparable sensitivity to traditional qPCR, but a simpler and more rapid operating process to obtain positive amplification. The qRPA, including the duplex strategy described here, could allow fast identification of the EP-causing T. equi and B. caballi, showing great potential for on-site EP screening of horses.
| S-EPMC7058082 | biostudies-literature
Project description:SynGAP is a potent regulator of biochemical signaling in neurons and plays critical roles in neuronal function. It was first identified in 1998, and has since been extensively characterized as a mediator of synaptic plasticity. Because of its involvement in synaptic plasticity, SynGAP has emerged as a critical protein for normal cognitive function. In recent years, mutations in the SYNGAP1 gene have been shown to cause intellectual disability in humans and have been linked to other neurodevelopmental disorders, such as autism spectrum disorders and schizophrenia. While the structure and biochemical function of SynGAP have been well characterized, a unified understanding of the various roles of SynGAP at the synapse and its contributions to neuronal function remains to be achieved. In this review, we summarize and discuss the current understanding of the multifactorial role of SynGAP in regulating neuronal function gathered over the last two decades.
| S-EPMC7046327 | biostudies-literature
Project description:In Brazil, dengue has been a major public health problem since its introduction in the 1980s. Phylogenetic studies constitute a valuable tool to monitor the introduction and spread of viruses as well as to predict the potential epidemiological consequences of such events. Aiming to perform the molecular characterization and phylogenetic analysis of DENV-2 during twenty years of viral activity in the country, viral strains isolated from patients presenting different disease manifestations (n?=?34), representing six states of the country, from 1990 to 2010, were sequenced. Partial genome sequencing (genes C/prM/M/E) was performed in 25 DENV-2 strains and full-length genome sequencing (coding region) was performed in 9 strains. The percentage of similarity among the DENV-2 strains in this study and reference strains available in Genbank identified two groups epidemiologically distinct: one represented by strains isolated from 1990 to 2003 and one from strains isolated from 2007 to 2010. No consistent differences were observed on the E gene from strains isolated from cases with different clinical manifestations analyzed, suggesting that if the disease severity has a genetic origin, it is not only due to the differences observed on the E gene. The results obtained by the DENV-2 full-length genome sequencing did not point out consistent differences related to a more severe disease either. The analysis based on the partial and/or complete genome sequencing has characterized the Brazilian DENV-2 strains as belonging to the Southeast Asian genotype, however a distinction of two Lineages within this genotype has been identified. It was established that strains circulating prior DENV-2 emergence (1990-2003) belong to Southeast Asian genotype, Lineage I and strains isolated after DENV-2 emergence in 2007 belong to Southeast Asian genotype, Lineage II. Furthermore, all DENV-2 strains analyzed presented an asparagine (N) in E390, previously identified as a probable genetic marker of virulence observed in DHF strains from Asian origin. The percentage of identity of the latter with the Dominican Republic strain isolated in 2001 combined to the percentage of divergence with the strains first introduced in the country in the 1990s suggests that those viruses did not evolve locally but were due to a new viral Lineage introduction in the country from the Caribbean.
| S-EPMC3597488 | biostudies-literature
Project description:This systematic literature review appraises critically the mediating variables of stereotype threat. A bibliographic search was conducted across electronic databases between 1995 and 2015. The search identified 45 experiments from 38 articles and 17 unique proposed mediators that were categorized into affective/subjective (n = 6), cognitive (n = 7) and motivational mechanisms (n = 4). Empirical support was accrued for mediators such as anxiety, negative thinking, and mind-wandering, which are suggested to co-opt working memory resources under stereotype threat. Other research points to the assertion that stereotype threatened individuals may be motivated to disconfirm negative stereotypes, which can have a paradoxical effect of hampering performance. However, stereotype threat appears to affect diverse social groups in different ways, with no one mediator providing unequivocal empirical support. Underpinned by the multi-threat framework, the discussion postulates that different forms of stereotype threat may be mediated by distinct mechanisms.
| S-EPMC4713435 | biostudies-literature
Project description:Coastal sea turtle stranding and bycatch are common phenomena worldwide and have received more attention in recent years. They are caused by both natural and anthropogenic factors. One thousand and seventy-two turtles were reported to be victims of these phenomena from March 1997 to November 2019 in Taiwan. Number of stranding/bycatch were variable and infrequent for the first 14 years, but increased each year after 2012 and peaked in 2019 with 217 cases. Most turtles were juveniles to subadults. All five of Taiwan's species were reported in stranding and bycatch records, and the green turtle was reported the most common. The main reported seasons lasted from winter to spring, when the weather changes dramatically. The sex ratio (female: male) ranged from 7 in the hawksbill turtle to 0.7 in the olive ridley, with an average of 2.4 for all species. Green turtles were the dominant stranded species, and more loggerhead turtles were by-caught. The hotspots were the towns of Dougou and Tochen in Yilan County, and Gongliao District in New Taipei City, located in NE coast of Taiwan respectively. Stranding was the more common of the two phenomena reported, and 80% of all stranded turtles were subadult green turtles. Eighty percent of all stranded/bycaught turtles were dead. Pond-nets were the fishing gear that accounted for the most bycatch, and captured mainly living young and subadult green turtles as well as subadult loggerhead turtles. The hotspots for bycatch were the towns of Dongou and Tochen in Yilan County. The Coast Guard and concerned citizen were the main sources of reports. This is the first study to analyze the long-term stranding/bycatch of sea turtles in Taiwan.
| S-EPMC6971529 | biostudies-literature
Project description:Background:Gaucher disease is a rare multi-systemic metabolic disorder resulting from the deficiency of acid ?-glucosidase activity, with consequent accumulation of glucocerebroside. Less than 15% of mean normal acid ?-glucosidase activity in leukocytes is the gold standard for the diagnosis of Gaucher disease, and is generally supplemented by a massive elevation in chitotriosidase activity. We report here our experience in the biochemical diagnosis of Gaucher disease by showing the heterogeneity of the activity of enzymes over 25 years from 1993-2017, through the analysis of 5128 clinically suspected Gaucher disease cases referred to the Biochemical Genetics Department, National Research Centre, as the main reference lab in Egypt for the diagnosis of Inherited Metabolic Disorders. Methods:Acid ?-glucosidase and chitotriosidase activities were measured in all referred cases. Sphinogmylinase activity was estimated for all cases with normal ?-glucosidase activity and moderate elevation of chitotriosidase. Results:Out of the 5128 suspected cases, 882 (17%) showed a deficiency in acid ?-glucosidase activity, accompanied by a raised chitotriosidase activity, ranges (213-66700 umol/l/h) and mean (7255 umol/l/h). Deficient chitotriosidase activity was found in 9 patients (1%) with low ?-glucosidase. 451 cases were diagnosed with acid sphingomyelinase deficiency patients (8.8%). Conclusion:Other biochemical markers are needed in addition to chitotriosidase for the diagnosis and follow up. Molecular testing was done to a relatively small number but needs to be done to all diagnosed patients as many mutations are known to predict the course of the disease.
| S-EPMC6838951 | biostudies-literature
Project description:BACKGROUND:Cardiac myxomas are the most frequent cardiac tumors. Although histologically benign, in some cases myxomas may be lethal, due to impairment of cardiac dynamics and their thromboembolic potential. The study aimed to assess the clinical presentation of cardiac myxomas and their correlation with echocardiographic features and to describe the perioperative results and long-term outcome of surgically treated patients. METHODS:A prospective study of 53 patients with cardiac myxomas who were operated the Hospital Argerich, followed clinically and with echocardiography from 1993 until 2013. All patients underwent echocardiographic studies. RESULTS:The patient's mean age was 53 ± 16 years (62.3% were women). The most common findings were dyspnea followed by embolic events. Most tumors were localized in the left atrium (77.4%), mainly in the fossa ovalis (63%). Mean size of the tumors was 4.76 x 3.50 cm. Tumors were generally mobile (88%) and went beyond the valve plane, causing mild mitral or tricuspid valve obstruction (58%) and dilation of the respective atrial chamber. Patients whose tumors were obstructive had higher pulmonary artery systolic pressures (50 vs 33 mmHg p < 0.01). According to the echocardiographic appearance 67% of tumors had a smooth surface and the remaining 32% had a villous surface. All patients with embolic manifestations had tumors with a villous surface. CONCLUSIONS:Clinical presentation relates to the ultrasound characteristics of myxomas. Smooth tumors are larger, occur with obstructive symptoms, and benefit from an elective surgery, whereas villous myxomas entailed a high embolic risk and require prompt surgical treatment.
| S-EPMC6358422 | biostudies-literature
Project description:About two decades ago, cloning of the autoimmune regulator (AIRE) gene materialized one of the most important actors on the scene of self-tolerance. Thymic transcription of genes encoding tissue-specific antigens (ts-ags) is activated by AIRE protein and embodies the essence of thymic self-representation. Pathogenic AIRE variants cause the autoimmune polyglandular syndrome type 1, which is a rare and complex disease that is gaining attention in research on autoimmunity. The animal models of disease, although not identically reproducing the human picture, supply fundamental information on mechanisms and extent of AIRE action: thanks to its multidomain structure, AIRE localizes to chromatin enclosing the target genes, binds to histones, and offers an anchorage to multimolecular complexes involved in initiation and post-initiation events of gene transcription. In addition, AIRE enhances mRNA diversity by favoring alternative mRNA splicing. Once synthesized, ts-ags are presented to, and cause deletion of the self-reactive thymocyte clones. However, AIRE function is not restricted to the activation of gene transcription. AIRE would control presentation and transfer of self-antigens for thymic cellular interplay: such mechanism is aimed at increasing the likelihood of engagement of the thymocytes that carry the corresponding T-cell receptors. Another fundamental role of AIRE in promoting self-tolerance is related to the development of thymocyte anergy, as thymic self-representation shapes at the same time the repertoire of regulatory T cells. Finally, AIRE seems to replicate its action in the secondary lymphoid organs, albeit the cell lineage detaining such property has not been fully characterized. Delineation of AIRE functions adds interesting data to the knowledge of the mechanisms of self-tolerance and introduces exciting perspectives of therapeutic interventions against the related diseases.
| S-EPMC5816566 | biostudies-literature
Project description:Gender equality is a major problem that places women at a disadvantage thereby stymieing economic growth and societal advancement. In the last two decades, extensive research has been conducted on gender related issues, studying both their antecedents and consequences. However, existing literature reviews fail to provide a comprehensive and clear picture of what has been studied so far, which could guide scholars in their future research. Our paper offers a scoping review of a large portion of the research that has been published over the last 22 years, on gender equality and related issues, with a specific focus on business and economics studies. Combining innovative methods drawn from both network analysis and text mining, we provide a synthesis of 15,465 scientific articles. We identify 27 main research topics, we measure their relevance from a semantic point of view and the relationships among them, highlighting the importance of each topic in the overall gender discourse. We find that prominent research topics mostly relate to women in the workforce-e.g., concerning compensation, role, education, decision-making and career progression. However, some of them are losing momentum, and some other research trends-for example related to female entrepreneurship, leadership and participation in the board of directors-are on the rise. Besides introducing a novel methodology to review broad literature streams, our paper offers a map of the main gender-research trends and presents the most popular and the emerging themes, as well as their intersections, outlining important avenues for future research.
| S-EPMC8454943 | biostudies-literature