106 research outputs found
Obtención de antÃgenos recombinantes del virus del Nilo Occidental en larvas de insecto: aplicación diagnóstica y capacidad inmunogénica y protectora en el modelo murino
Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de BiologÃa Molecular. Fecha de lectura: 16/12/201
How effective are rapid diagnostic tests for Chagas disease?
© 2021 Informa UK Limited, trading as Taylor & Francis Group. Introduction: Diagnosis of chronic Chagas disease relies on the agreement of two conventional serological tests based on distinct antigens. These require cold to preserve reagents and samples, and equipment and trained personnel to run them. Moreover, results turnaround may be delayed for several weeks risking a loss to follow-up of infected subjects, summoning major disadvantages to access diagnosis (and treatment) in many highly endemic areas. Areas covered: Recent studies have shown the versatility of rapid diagnostic tests for the detection of chronic Trypanosoma cruzi infections in referral centers and in field campaigns, with a performance equivalent to that of conventional tools. Remarkably, RDTs do not require cold storage and provide results within an hour. Additionally, they are easy-to-use and can work with a tiny volume of finger-pricked whole blood. Altogether, major advantages toward generalizing their use as an alternative to conventional tests. Expert opinion: Already in 2021, only a small percentage of T. cruzi-infected people are diagnosed and treated. The unsuitability of currently used diagnostics, and of the recommended algorithm, to the conditions found in many regions do not help to fill this gap. RDTs stand as a promising solution, even though geographical validation should precede their implementation
Parasitological, serological and molecular diagnosis of acute and chronic chagas disease: From field to laboratory
There is no consensus on the diagnostic algorithms for many scenarios of Trypanosoma cruzi infection, which hinders the establishment of governmental guidelines in endemic and non-endemic countries. In the acute phase, parasitological methods are currently employed, and standardised surrogate molecular tests are being introduced to provide higher sensitivity and less operator-dependence. In the chronic phase, IgG-based serological assays are currently used, but if a single assay does not reach the required accuracy, PAHO/WHO recommends at least two immunological tests with different technical principles. Specific algorithms are applied to diagnose congenital infection, screen blood and organ donors or conduct epidemiological surveys. Detecting Chagas disease reactivation in immunosuppressed individuals is an area of increasing interest. Due to its neglect, enhancing access to diagnosis of patients at risk of suffering T. cruzi infection should be a priority at national and regional levels.Fil: Schijman, Alejandro Gabriel. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Investigaciones en IngenierÃa Genética y BiologÃa Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Alonso Padilla, Julio. Universidad de Barcelona; EspañaFil: Longhi, Silvia Andrea. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Investigaciones en IngenierÃa Genética y BiologÃa Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Picado, Albert. Foundation For Innovative New Diagnostics; Suiz
Molecular diagnostics for Chagas disease: up to date and novel methodologies
Chagas disease is caused by the parasite Trypanosoma cruzi. It affects 7 million people, mainly in Latin America. Diagnosis is usually made serologically, but at some clinical scenarios serology cannot be used. Then, molecular detection is required for early detection of congenital transmission, treatment response follow up, and diagnosis of immune-suppression reactivation. However, present tests are technically demanding and require well-equipped laboratories which make them unfeasible in low-resources endemic regions
Computational Analysis of African Swine Fever Virus Protein Space for the Design of an Epitope-Based Vaccine Ensemble
African swine fever virus is the etiological agent of African swine fever, a transmissible severe hemorrhagic disease that affects pigs, causing massive economic losses. There is neither a treatment nor a vaccine available, and the only method to control its spread is by extensive culling of pigs. So far, classical vaccine development approaches have not yielded sufficiently good results in terms of concomitant safety and efficacy. Nowadays, thanks to advances in genomic and proteomic techniques, a reverse vaccinology strategy can be explored to design alternative vaccine formulations. In this study, ASFV protein sequences were analyzed using an in-house pipeline based on publicly available immunoinformatic tools to identify epitopes of interest for a prospective vaccine ensemble. These included experimentally validated sequences from the Immune Epitope Database, as well as de novo predicted sequences. Experimentally validated and predicted epitopes were prioritized following a series of criteria that included evolutionary conservation, presence in the virulent and currently circulating variant Georgia 2007/1, and lack of identity to either the pig proteome or putative proteins from pig gut microbiota. Following this strategy, 29 B-cell, 14 CD4 + T-cell and 6 CD8 + T-cell epitopes were selected, which represent a starting point to investigating the protective capacity of ASFV epitope-based vaccines
Computational Analysis of African Swine Fever Virus Protein Space for the Design of an Epitope-Based Vaccine Ensemble
African swine fever virus is the etiological agent of African swine fever, a transmissible severe hemorrhagic disease that affects pigs, causing massive economic losses. There is neither a treatment nor a vaccine available, and the only method to control its spread is by extensive culling of pigs. So far, classical vaccine development approaches have not yielded sufficiently good results in terms of concomitant safety and efficacy. Nowadays, thanks to advances in genomic and proteomic techniques, a reverse vaccinology strategy can be explored to design alternative vaccine formulations. In this study, ASFV protein sequences were analyzed using an in-house pipeline based on publicly available immunoinformatic tools to identify epitopes of interest for a prospective vaccine ensemble. These included experimentally validated sequences from the Immune Epitope Database, as well as de novo predicted sequences. Experimentally validated and predicted epitopes were prioritized following a series of criteria that included evolutionary conservation, presence in the virulent and currently circulating variant Georgia 2007/1, and lack of identity to either the pig proteome or putative proteins from pig gut microbiota. Following this strategy, 29 B-cell, 14 CD4+ T-cell and 6 CD8+ T-cell epitopes were selected, which represent a starting point to investigating the protective capacity of ASFV epitope-based vaccines.info:eu-repo/semantics/publishedVersio
Seroprevalence of Porcine torovirus (PToV) in Spanish farms
Background: Torovirus infections have been associated with gastroenteritis and diarrhea in horses, cows, pigs and humans, especially in young animals and in children. Although asymptomatic in a large percentage of cases, however toroviruses may pose a potential threat to worsen disease outcome in concurrent infections with other enteric pathogens. Previous studies based on the analysis of limited numbers of samples indicated high seroprevalences against porcine torovirus (PToV) in various European countries. The aim of this work was to perform a seroepidemiological survey of PToV in Spanish farms in order to define the seroprevalence against this virus. Results: Serum samples (n = 2664) from pigs of different ages were collected from 100 Spanish farms coming from 10 regions that concentrate 96.1% of the 3392 farms with 80 or more sows censused in Spain. Samples were screened by means of an indirect enzyme-linked immune-sorbent assay (ELISA) based on a recombinant PToV nucleocapsid protein as antigen. The analysis of the whole serum collection yielded a total of 95.7% (2550/2664) seropositive samples. The highest prevalence (99.6%, 1382/1388) and ELISA values (average O.D. ± standard deviation) were observed in the sows (1.03±0.36) and the lowest prevalence (59.4%, 98/165) and anti-PToV IgG levels (0.45±0.16) were found amongst 3-week-old piglets. Both ELISA reactivity values and seroprevalence percentages rose quickly with piglet's age from 3 to 11 weeks of age; the seroprevalence was 99.3% (2254/2270) when only the samples from sows and pigs over 11-weeks of age were considered. Antibodies against PToV were detected in all analyzed farms. Conclusions: This report describes the results of the largest torovirus seroepidemiological survey in farmed swine performed so far. Overall, the seroprevalence against PToV in animals older than 11 weeks of age was >99%, indicating that this virus is endemic in pig herds from Spain
In silico Design of an Epitope-Based Vaccine Ensemble for Chagas Disease
Trypanosoma cruzi infection causes Chagas disease, which affects 7 million people
worldwide. Two drugs are available to treat it: benznidazole and nifurtimox. Although
both are efficacious against the acute stage of the disease, this is usually asymptomatic
and goes undiagnosed and untreated. Diagnosis is achieved at the chronic stage, when
life-threatening heart and/or gut tissue disruptions occur in ∼30% of those chronically
infected. By then, the drugs’ efficacy is reduced, but not their associated high toxicity.
Given current deficiencies in diagnosis and treatment, a vaccine to prevent infection
and/or the development of symptoms would be a breakthrough in the management
of the disease. Current vaccine candidates are mostly based on the delivery of single
antigens or a few different antigens. Nevertheless, due to the high biological complexity
of the parasite, targeting as many antigens as possible would be desirable. In this
regard, an epitope-based vaccine design could be a well-suited approach. With this
aim, we have gone through publicly available databases to identify T. cruzi epitopes
from several antigens. By means of a computer-aided strategy, we have prioritized a
set of epitopes based on sequence conservation criteria, projected population coverage
of Latin American population, and biological features of their antigens of origin. Fruit of
this analysis, we provide a selection of CD8+ T cell, CD4+ T cell, and B cell epitopes that
have <70% identity to human or human microbiome protein sequences and represent
the basis toward the development of an epitope-based vaccine against T. cruzi
Host-Derived Molecules as Novel Chagas Disease Biomarkers: Hypercoagulability Markers in Plasma
The most severe clinical symptomatology of Chagas disease
affects ~30% of those chronically infected with the Trypanosoma
cruzi parasite. The pathogenic mechanisms that lead to
life-threatening heart and gut tissue disruptions occur
"silently" for a longtime in a majority of cases. As a result,
despite there are several serological and molecular methods
available to diagnose the infection in its acute and chronic
stages, diagnosis is often achieved only after the onset of
clinical symptoms in the chronic phase of the disease.
Furthermore, although there are two drugs to treat it, the
assessment of their performance is impractical with current
parasite-derived diagnostics, and therapeutic efficacy cannot be
acknowledged in a timely manner.In this chapter we present two
procedures to measure host-derived molecules as surrogates of
therapeutic response against chronic T. cruzi infection. Their
outputs relate to the generation and activity of thrombin, a
major component of the blood coagulation cascade. This is due to
the fact that a hypercoagulability state has been described to
occur in chronic Chagas disease patients and revert after
treatment with benznidazole
State-of-the-art in host-derived biomarkers of Chagas disease prognosis and early evaluation of anti-Trypanosoma cruzi treatment response
Chagas disease is caused by infection with the parasite
Trypanosoma cruzi, which might lead to a chronic disease state
and drive to irreversible damage to the heart and/or digestive
tract tissues. Endemic in 21 countries in the Americas, it is
the neglected disease with a highest burden in the region.
Current estimates point at ~6 million people infected, of which
~30% will progress onto the symptomatic tissue disruptive stage.
There is no vaccine but there are two anti-parasitic drugs
available: benznidazole and nifurtimox. However, their efficacy
is variable at the chronic symptomatic stage and both have
frequent adverse effects. Since there are no prognosis markers,
drugs should be administered to all T. cruzi-infected
individuals in the indeterminate and early symptomatic stages.
Nowadays, there are no tests-of-cure either, which greatly
undermines patients' follow-up and the search of safer and more
efficacious drugs. Therefore, the identification and validation
of biomarkers of disease progression and/or treatment response
on which to develop tests of prognosis and/or cure is a major
research priority. Both parasite- and host-derived markers have
been investigated. In the present manuscript we present an
updated outlook of the latter
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