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Introduction
Publications
Publications (558)
Mpox (formerly known as monkeypox) is an infectious disease caused by MPXV, a member of the family Poxviridae. On July 23, 2022, the WHO declared the first Public Health Emergency of International Concern of Mpox due to an escalating global outbreak with low intensity. Two clades of MPXV and sev-eral lineages within each of these clades have been d...
Wastewater-based epidemiological surveillance has proven to be a useful and cost-effective tool for detecting COVID-19 outbreaks. Here, our objective was to evaluate its potential as an early warning system in Venezuela by detecting SARS-CoV-2 RNA in wastewater and its correlation with reported cases of COVID-19. Viral RNA was concentrated from was...
The COVID-19 pandemic was characterized by the emergence and succession of SARS-CoV-2 variants able to evade the antibody response induced by natural infection and vaccination. To evaluate the IgG reactivity and neutralizing capacity of the serum of individuals vaccinated with Sputnik V (105 volunteers vaccinated) against different viral variants....
SARS-CoV-2 vaccines have contributed to attenuating the burden of the COVID-19 pandemic by promoting the development of effective immune responses, thus reducing the spread and severity of the pandemic. A clinical trial with the Sputnik-V vaccine was conducted in Venezuela from December 2020 to July 2021. The aim of this study was to explore the an...
Keywords: COVID-19, SARS-CoV-2, Antibody, ELISA, Spike, S1, S2, RBD, epitopes, Neutralization
The Receptor Binding Domain (RBD) of SARS-CoV-2, the virus responsible for the COVID-19 pandemic, is the functional region of the viral Spike protein (S), which is involved in cell attachment to target cells. The virus has accumulated progressively mutations in its genome, particularly in the RBD region, many of them associated with immune evasion...
Hepatitis B is a “silent epidemic” that is fifty to a hundred (50–100) times more infectious than HIV and is a potentially life-threatening liver infection [...]
The Receptor Binding Domain (RBD) of SARS-CoV-2, the virus responsible for the COVID-19 pandemic, is the functional region of the viral Spike protein (S), which is involved in cell attachment to target cells. The virus has accumulated progressively mutations in its genome, particularly in the RBD region, many of them associated with immune evasion...
Objective:
Despite the availability of a highly effective and safe vaccine against hepatitis B virus (HBV) infection for 40 years, still almost 300 million persons are estimated to be chronically infected by this virus worldwide. The World Health Organization (WHO) has proposed a plan for hepatitis elimination by 2030. However, several factors, su...
Hepatitis B virus (HBV) genotypes E to J are understudied genotypes. Genotype E is found almost exclusively in West Africa. Genotypes F and H are found in America and are rare in other parts of the world. The distribution of genotype G is not completely known. Genotypes I and J are found in Asia and probably result from recombination events with ot...
The emergence of the SARS-CoV-2 Variant of Concern (VOC), Omicron, has been characterized by an explosive number of cases in almost every part of the world. The dissemination of different sub-lineages and recombinant genomes also led to several posterior waves in many countries. The circulation of this VOC and its major sub-lineages (BA.1 to BA.5)...
The emergence of the SARS-CoV-2 Variant of Concern (VOC) Omicron has been characterized by an explosive number of cases in almost every part of the world. The dissemination of different sub-lineages and recombinant genomes also led to several posterior waves in many countries. The circulation of this VOC and its major sub-lineages (BA.1 to BA.5) wa...
The resources and platforms available on the internet for collect-ing and sharing information and performing genomic sequence analysis have made it possible to follow closely the evolution the evolution of SARS-CoV-2. However, the current monkeypox outbreak in the world brings us back to the need to use these resources to appraise the extent of thi...
The ongoing epidemic of monkeypox virus (MPXV) infection has already reached more than 50,000 persons worldwide until the end of August 2022. We report the first case detected in Venezuela. The patient reported traveling from Spain and contact with friends tested positive for MPXV after his return. Partial complete genome phylogenetic analysis allo...
Objetivos. Determinar los cambios en las características clínicas y desenlaces intrahospitalarios de los pacientes hospitalizados por COVID-19 en un hospital privado de Caracas durante dos años de pandemia. Materiales y métodos. Estudio retrospectivo, observacional, de pacientes hospitalizados por COVID-19. Se investigó la correspondencia entre las...
By the end of 2021, the Omicron variant of SARS-CoV-2, the coronavirus responsible for COVID-19, emerges, causing immediate concern, due to the explosive increase in cases in South Africa and a large number of mutations. This study describes the characteristic mutations of the Omicron variant in the Spike protein, and the behavior of the successive...
Some of the lineages of SARS-CoV-2, the new coronavirus responsible for COVID-19, exhibit higher transmissibility or partial resistance to antibody-mediated neutralization and were designated by WHO as Variants of Interests (VOIs) or Concern (VOCs). The aim of this study was to monitor the dissemination of VOIs and VOCs in Venezuela from March 2021...
Some of the lineages of SARS-CoV-2, the new coronavirus responsible for COVID-19, exhibit higher transmissibility or partial resistance to antibody mediated neutralization and were des-ignated by WHO as Variants of Interests (VOIs) or Concern (VOCs). The aim of this study was to monitor the dissemination of VOIs and VOCs in Venezuela during a year....
Background
By the end of 2021, the SARS-CoV-2 Variant of Concern (VOC) Delta was predominant in most of the world. At the end of November, the Omicron variant was first detected in South Africa. This variant was immediately classified as VOC, due to the explosive increase of cases in South Africa, and the great number of mutations exhibited by this...
By the end of 2021, the Omicron variant of concern (VOC) emerges in South Africa. This variant caused immediate concern, due to the explosive increase in cases associated with it and the large number of mutations it exhibits. In this study, the restriction sites that allow detecting the mutations K417N and N440K in the Spike gene are described. Thi...
Hepatitis B virus (HBV) infection remains a global public health issue: a number of barriers still hamper the control of the HBV epidemic and in finding a cure for HBV [...]
Introducción. Los primeros casos de la COVID-19 se reportaron en China a principios de diciembre del 2019 y el descubrimiento de su agente etiológico, el virus SARS-CoV-2, se anunció en enero del 2020. El conocimiento adquirido sobre la estructura y biología del SARS-CoV-2 permitió, entre otras cosas, el rápido desarrollo de varias vacunas contra l...
La infección generada por el SARS-CoV-2 ha causado más de 200 millones de casos y de 4,5 millones de muertes en todo el mundo. El SARS-CoV-2 ha ido acumulando mutaciones que permiten clasificarlo en diferentes linajes. Algunos de esos linajes han sido denominados variantes por la OMS: bajo vigilancia (VUM), de interés (VOI) o de preocupación (VOC)....
Introducción: El agente etiológico responsable de COVID-19, SARSCoV-2, es un virus ARN perteneciente a la familia Coronaviridae. Durante la replicación, los componentes virales interactúan con la maquinaria celular induciendo alteraciones en la fisiología celular, lo que contribuye a la patogénesis del virus. Método: Revisión bibliográfica en NCBI/...
Introducción. Los primeros casos de la COVID-19 se reportaron en China a principios de diciembre del 2019 y el descubrimiento de su agente etiológico, el virus SARS-CoV-2, se anunció en enero del 2020. El conocimiento adquirido sobre la estructura y biología del SARS-CoV-2 permitió, entre otras cosas, el rápido desarrollo de varias vacunas contra l...
This communication summarizes the presentations given at the 1st international conference of the World Society for Virology (WSV) held virtually during 16–18 June 2021, under the theme of tackling global viral epidemics. The purpose of this biennial meeting is to foster international collaborations and address important viral epidemics in different...
SARS-CoV-2 causes coronavirus disease 2019 (COVID-19) also in pregnant women. Infection in pregnancy leads to maternal and placental functional alterations. Pregnant women with vascular defects such as preeclampsia show high susceptibility to SARS-CoV-2 infection by undefined mechanisms. Pregnant women infected with SARS-CoV-2 show higher rates of...
Variants of Concern or Interest of SARS-CoV-2 (VOC or VOI), the coronavirus responsible for COVID-19, have emerged in several countries. Mutations in the amino acid 452 of the Spike protein are particularly important and associated with some of these variants: L452R, present in Delta VOC, and L452Q, present in Lambda VOI. These mutations have been...
In less than two years since SARS-CoV-2 emerged, the new coronavirus responsible for COVID-19, has accumulated a great number of mutations. Many of these mutations are located in the Spike protein and some of them confer to the virus higher transmissibility or partial resistance to antibody mediated neutralization. Viral variants with such confirme...
Variants of Concern of SARS-CoV-2 (VOCs), the new coronavirus responsible for COVID-19, have emerged in several countries. Mutations in the amino acid 484 of the Spike protein are particularly important and associated with some of these variants: E484K or E484Q. These mutations have been associated with evasion to neutralizing antibodies. Restricti...
Emerging viruses such as the COVID-19-inducing virus, SARSCoV- 2, represent a threat to human health, unless effective vaccines, drugs or alternative treatments, such as passive immunization, become accessible. Animal-derived immunoglobulins, such as equine immunoglobulins might be useful as immunoprophylaxis or immunotherapy against this viral dis...
The coronavirus that causes COVID-19 is called SARS-CoV-2. This virus belongs to the family Coronaviridae. Pregnant women are not exempt from infection by this new virus. The placenta is a highly specialized pregnancy organ that supports the normal growth and development of the fetus. There is evidence that the placenta is permissive to infection b...
Diferentes plataformas vacunales han sido utilizadas para producir vacunas contra la COVID-19, entre ellas, virus completos inactivados (ej, Sinopharm, Sinovac. Covaxin), ácido ribonucleico mensajero (ej, Pfizer/BioNTech, Moderna), proteínas recombinantes presentadas como nanopartículas (ej, Novavax), y el uso de vectores de adenovirus (ej. Sputnik...
Introduction: Variants of Concern of SARS-CoV-2 (VOCs), the new coronavirus responsible for COVID-19, have emerged in several countries. Two mutations in the gene coding for the Spike protein of the viral genome are particularly important and associated with some of these variants: E484K and N501Y. Restriction enzyme analysis is proposed as a rapid...
La pandemia de COVID-19, causada por el SARS-CoV-2, ha provocado una revolución científica desde todo punto de vista. El ejemplo más emblemático es la acelerada y exitosa producción de varias vacunas efectivas contra esta enfermedad (1). Otro ejemplo lo constituye el extraordinario número de secuencias de genomas de este virus obtenidas mundialment...
Como respuesta a la emergencia de la pandemia de la COVID-19, en los últimos 18 meses, se ha llevado a cabo una intensa actividad de investigación y desarrollo de vacunas contra el SARS-CoV-2. Eso ha resultado, hasta ahora, en la autorización para uso de emergencia de al menos ocho vacunas basadas en diferentes plataformas, especialmente usando vir...
Several diagnostic tools have been developed for clinical and epidemiological assays. RT-PCR and antigen detection tests are more useful for diagnosis of acute disease, while antibody tests allow the estimation of exposure in the population. Currently, there is an urgent need for the development of diagnostic tests for COVID-19 that can be used for...
Hepatitis B virus (HBV) classification comprises up to 10 genotypes with specific geographical distribution worldwide, further subdivided into 40 subgenotypes, which have different impacts on liver disease outcome. Though extensively studied, the classification of subgenotype A sequences remains ambiguous. This study aimed to characterize HBV isola...
The increasing number of SARS-CoV-2 variants associated with highly transmissible phenotypes is a health-public concern in the current pandemic scenario. Herein, we developed a comprehensive in silico analysis of the changes occurring upon mutations in the viral spike. We focused on mutants located in the receptor-binding domain of the viral spike...
SARS-CoV-2 is the new coronavirus responsible for COVID-19 disease. The first two cases of COVID-19 were detected in Venezuela on March 13, 2020. The aim of this study was the genetic characterization of Venezuelan SARS-CoV-2 isolates. A total of 7 full SARS-CoV-2 genome sequences were obtained by Sanger sequencing, from patients of different regio...
Background: The emergence of severe acute respiratory
syndrome coronavirus 2 (SARS-CoV-2) and its disease COVID-19 has strongly encouraged the search for antiviral compounds. Most of the evaluated drugs against SARS-CoV-2 derive from drug repurposing of Food and Drug Administration-approved molecules. These drugs have as target three major processe...
The first week of October is the season to announce the winners of the Nobel Prizes of sciences such as Physics, Physiology or Medicine and Chemistry. CientMed celebrates this occasion by inviting two well known Venezuelan scientists to comment on the significance of the last two prizes, and share their corresponding deep knowledge and experience o...
Recent reports have shown that small and big felines could be infected by SARS-CoV-2, while other animals, like swines and mice, are apparently not susceptible to this infection. These findings raise the question of the role of cell factors associated with early stages of the viral infection in host selectivity. The cellular receptor for SARS-CoV-2...
Background and aims
Sub-Saharan Africa (SSA) is the region with the most patients co-infected with the human immunodeficiency virus (HIV) and the hepatitis B virus (HBV) worldwide. However, few studies have focused on SSA children who are at a higher risk of developing a chronic infection than adults. Furthermore, children on first-line antiretrovi...
Hepatitis delta virus (HDV) is a defective human virus that lacks the ability to produce its own envelope proteins and is thus dependent on the presence of a helper virus, which provides its surface proteins to produce infectious particles. Hepatitis B virus (HBV) was so far thought to be the only helper virus described to be associated to HDV. How...
Hepatitis B virus (HBV) chronic infection is responsible for almost 900.000 deaths each year, due to cirrhosis or hepatocellular carcinoma (HCC). Ten HBV genotypes have been described (A–J). HBV genotype F and H circulate in America. HBV genotypes have been further classified in subgenotypes. There is a strong correlation between the genetic admixt...
Many human viral diseases are a consequence of a zoonotic event. Some of the diseases caused by these zoono-tic events have affected millions of people around the world, some of which have resulted in high rates of mor-bidity/mortality in humans. Changes in the viral proteins that function as ligands of the host receptor may promote the spillover b...
Direct-acting antivirals are effective tools to control viral infections. SARS-CoV-2 is a coronavirus associated with the epidemiological outbreak in late 2019. Previous reports showed that HIV-1 protease inhibitors could block SARS-CoV main protease. Based on that and using an in silico approach, we evaluated SARS-CoV-2 main protease as a target f...
Objective:
Hepatitis C virus (HCV) infection is a public health problem and a major cause of chronic hepatitis. This virus exhibits a great genetic variability, with 8 genotypes and numerous subtypes. The aim of this study was to evaluate the fluctuations of HCV subtypes during 2 decades in Venezuela.
Methods:
HCV genotypes were determined by di...
Marcetia taxifolia is a neotropical plant present in South America and it has been evaluated in several biological models due to the presence of active metabolites. Nevertheless, there is a limited quantity of studies related to the antiviral activity of the compounds present in this genus. In our work, the antiviral effect of the compounds isolate...
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Introducción.
El virus de la hepatitis C (HCV) presenta una gran variabilidad genética, con siete genotipos y numerosos subtipos. La determinación del tipo viral ha sido fundamental para la escogencia y la duración del tratamiento antiviral adecuado. En Venezuela, el genotipo 2 del HCV es relativamente diverso, siendo particularmente prevalente el...
Prevalence and molecular epidemiology studies for hepatitis B (HBV) and C (HCV) virus are scarce in Warao Amerindians from Venezuela, where an epidemic of human immunodeficiency virus type 1 (HIV-1) has recently been documented. To carry out a molecular epidemiology analysis of hepatitis B (HBV) and C (HCV) virus in Warao individuals from the Delta...
Abstract - Methoxyflavones are flavonoid widely distributed in plants and has been
reported as potent antitumor agents and some of them have shown activity against HIV-1.
In this work, two methoxyflavones isolated from Marcetia taxifolia were evaluated in
vitro and in silico as HIV-1 inhibitors. Pentamethoxyflavone (5,3'-dihydroxy-3,6,7,8,4'-
penta...
Abstract
Background:
Plant extracts are sources of valuable compounds with biological activity, especially for the anti-
proliferative activity against pathogens or tumor cells. Myricetin is a flavonoid found in several plants that has been described as an inhibitor of Human immunodeficiency virus type 1 (HIV-1) through its action against the HIV r...
This book is a compilation of some of the most remarkable contributions made by scientists currently working in Latin America to the understanding of virus biology, the pathogenesis of virus-related diseases, virus epidemiology, vaccine trials and antivirals development. In addition to recognizing the many fine virologists working in Latin America,...
Flavonoids are present in practically all plants and many biological activities have been described for them. The flavonoid quercetin is a common molecule for which anti-HIV activity has been demonstrated. Avicularin and guajaverin are derivatives of quercetin with a glycoside substituent in their structure. In this work, a mixture of both derivati...
Globally, about 50% of liver cancer originates as a result of long term infection with hepatitis B virus (HBV), and some genotypes and mutations have been associated with an increased severity of infection. The aim of this study was to evaluate the genetic diversity of HBV in patients from Venezuela, with chronic infection, cirrhosis and hepatocell...
Around 3% of the human population is infected with hepatitis C virus (HCV) and 70-80% of these individuals develop a chronic infection. There is no vaccine available against HCV and up to 50% of the infected patients do not respond to standard therapy, based on the combination of interferon-alpha (IFN-α) and ribavirin. Recently, direct acting antiv...
The World Health Organization estimates that approximately 170 million people are chronically infected with hepatitis C virus (HCV). This study evaluated the presence of antibodies against HCV by two immunoassays. HCV genotypes were analyzed by phylogenetic analysis of viral genome fragments amplified from the 5 ʼnon-coding (5‘NC) region and non-str...
Palabras clave: hepatitis C; terapia; antivirales de acción directa; blancos celulares. Resumen. Un 3% de la población mundial está infectado por el virus de la hepatitis C (VHC). Un 70-80% de los individuos infectados desarrollan una infección crónica. No se dispone de una vacuna contra la hepatitis C y aproximadamente 50% de los pacientes infecta...
We previously reported a high prevalence of HIV-1 infection in Warao Amerindians from Venezuela due to the rapid spread of a single B subtype strain. In this study we evaluated the co-receptor use of the HIV-1 strains infecting this Amerindian community. Sequences of the HIV-1 V3 loop from 56 plasma samples were genotyped for co-receptor use. An ex...
Chronic hepatitis B remains as a major public health problem, with more than 350 million people infected world-wide. Available therapies have limited efficacy and require long-term continuous treatments, further encouraging the development of therapeutic vaccines as a promising approach. In this sense, a new vaccine formulation called HeberNasvac w...
Several species of alphaviruses have been previously described in the Americas, some of which are associated with encephalitis and others are associated with arthralgia. Venezuelan equine encephalitis virus (VEEV) and eastern equine encephalitis virus (EEEV) are endemic to Venezuela, with the former being responsible for major outbreaks of severe a...
The genetic diversity of HBV in human population is often a reflection of its genetic admixture. The aim of this study was to explore the genotypic diversity of HBV in Cuba. The S genomic region of Cuban HBV isolates was sequenced and for selected isolates the complete genome or precore-core sequence was analyzed. The most frequent genotype was A (...