Esmeralda Vizzi

Esmeralda Vizzi
Venezuelan Institute for Scientific Research | IVIC · Centro de Microbiología y Biología Celular

PhD

About

65
Publications
3,029
Reads
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680
Citations
Additional affiliations
January 2001 - October 2020
Venezuelan Institute for Scientific Research
Position
  • Head of Department

Publications

Publications (65)
Article
Full-text available
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...
Article
Introducción: La infección por SARS-CoV-2 determina desde formas asintomáticas hasta manifestaciones muy graves de COVID-19 que pueden comprometer la vida. El impacto de la pandemia por COVID-19 plantea la necesidad de identificar los factores de riesgo que condicionan la variabilidad interindividual en la susceptibilidad a la infección por SARS-Co...
Article
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/...
Article
Full-text available
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...
Article
Background : Human cosavirus (HCoSV) is a new member of the Picornaviridae family, geographically widespread among humans. It has been suggested as a causative agent of acute gastroenteritis, but its pathogenicity is not currently certain. In HIV-infected subjects, diarrhoea is one of the most frequent gastrointestinal manifestations, whose aetiolo...
Article
Full-text available
Background The role of rotavirus as main etiologic agent of diarrhea has been well documented worldwide, including in Venezuela. However, information about the prevalence of gastrointestinal viruses such as calicivirus, adenovirus and astrovirus is limited and the contribution of other agents as Aichi virus and klassevirus is largely unknown. To ex...
Article
Full-text available
Background Rotavirus (RV) is the most common cause of severe childhood diarrhea worldwide. Despite Venezuela was among the first developing countries to introduce RV vaccines into their national immunization schedules, RV is still contributing to the burden of diarrhea. Concerns exist about the selective pressure that RV vaccines could exert on the...
Article
Chikungunya virus is an Alphavirus that causes chikungunya Fever (CHIKF). In Venezuela, a region devoid of immunity against CHIKV and presence of Aedes aegypti and Aedes albopictus. The first imported case was reported by health authorities in June 2014. The relevance of the fact, 94 samples of febrile patients who came to the centers of public and...
Article
Full-text available
Glucose-6-phosphate dehydrogenase (G6PD) deficiency causes acute haemolytic anaemia triggered by oxidative drugs such as primaquine (PQ), used for Plasmodium vivax malaria radical cure. However, in many endemic areas of vivax malaria, patients are treated with PQ without any evaluation of their G6PD status. G6PD deficiency and its genetic heterogen...
Article
Full-text available
RESUMEN El virus chikungunya (CHIKV) es un Alfavirus causante de la fiebre chikungunya (CHIKF). En Venezuela, una región desprovista de inmunidad contra CHIKV y con presencia de Aedes aegypti y Aedes albopictus, el primer caso importado fue reportado por las autoridades sanitarias en junio de 2014. Por la relevancia del hecho, se analizaron 94 mues...
Article
Full-text available
Several studies have shown that adaptation of various viruses to grow in certain cell lines of vertebrates, leads to the selection of virus variants that bind heparan sulfate (HS) with high affinity. In this study we investigated the susceptibility of strains of dengue virus (DENV) to oversulfated heparin an analogue of HS after passages in BHK-21...
Article
Gastrointestinal disorders or GID are debilitating conditions common in individuals infected by the human immunodeficiency virus (HIV), capable of leading to death. Numerous etiological agents and pathophysiological mechanisms have been involved in this status. Although the use of highly active antiretroviral therapy (HAART) in many countries has g...
Article
Full-text available
Rotavirus infection induces an increase in [Ca(2+)](cyto), which in turn may affect the distribution of the cytoskeleton proteins in the infected cell. Changes in microfilaments, including the formation of stress fibers, were observed starting at 0.5 h.p.i. using fluorescent phalloidin. Western blot analysis indicated that RhoA is activated between...
Data
Distribution of actin in DxRRV-infected cells and DxRRV-infected cells treated with BAPTA and siRNA NSP4. Cells were DxRRV-infected (A) and DxRRV-infected treated with BAPTA and siRNA NSP4 (F,K). At 7 h.p.i. DxRRV-infected cells and mock-infected cells (P), were fixed and processed for immunofluorescence. Actin filaments were stained with Alexa 586...
Article
Rotavirus infection is the most common cause of severe gastroenteritis during childhood worldwide, especially in developing countries. Two rotavirus vaccines are available for childhood immunization programs. Evaluation of the vaccine performance will benefit from knowledge of the epidemiological features of rotavirus infection in regional settings...
Article
Porcine enteric sapovirus (PES) has been shown to cause diarrhea under experimental conditions in gnotobiotic piglets. However, the role of PES as enteric pathogens in porcine farms remains unclear. To further understand the PES-host interactions under field conditions, a serological survey was carried out. To this end the capsid gene of a PES isol...
Article
Full-text available
The circulation of Aichi virus in a major urban area was demonstrated using molecular detection with samples recovered from a major river polluted with sewage discharges in Caracas, Venezuela. Five out of 11 water samples studied were positive, being classified by phylogenetic analysis as genotype B. Analysis of sewage waters appears to be a useful...
Article
Full-text available
The detection and molecular characterization of pathogenic human viruses in urban sewage have been used extensively to derive information on circulating viruses in given populations throughout the world. In this study, a similar approach was applied to provide an overview of the epidemiology of waterborne gastroenteritis viruses circulating in urba...
Article
Full-text available
Rotavirus infection of cells in culture induces major changes in Ca2+ homeostasis. These changes include increases in plasma membrane Ca2+ permeability, cytosolic Ca2+ concentration, and total cell Ca2+ content and a reduction in the amount of Ca2+ released from intracellular pools sensitive to agonists. Various lines of evidence suggest that the n...
Article
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Recibido 14 de octubre de 2006; aceptado 8 de febrero de 2007 ______________________________________________________________________________________________________________ Resumen: En un estudio realizado en 1984 en la Maternidad "Concepción Palacios", Pérez-Schael y col. detectaron excreción asintomáti-ca de rotavirus en el 56% de los recién naci...
Article
Full-text available
The frequency of the C282Y, H63D and S65C alleles of the HFE gene was determined in a sample of the Venezuelan population. Two new sets of primers were tested for amplifying the regions mapping these mutations, and genotyping was performed by restriction fragment length polymorphism (RFLP). DNA sequencing was used to validate the RFLP analysis. Ser...
Article
Full-text available
The immune response elicited by the rotavirus nonstructural protein NSP4 and its potential role in protection against rotavirus disease are not well understood. We investigated the serological response to NSP4 and its correlation with disease protection in sera from 110 children suffering acute diarrhea, associated or not with rotavirus, and from 2...
Article
The importance of enteric viral infections in HIV-related diarrhea is uncertain. Human caliciviruses have emerged as a leading cause of acute diarrhea worldwide. To evaluate the importance of calicivirus infections in HIV-related diarrhea. Study design 151 fecal samples collected from children and adults infected with HIV, with and without diarrhea...
Article
We report a significant high incidence of infection with G9P[8] rotavirus in Italian children during the winter epidemic season 1999-2000. The study was carried out on 439 children < 4 years hospitalized with acute diarrhea in Palermo. G9P[8] strains constituted 19% of all rotavirus identified and were not associated with more severe forms of gastr...
Article
Full-text available
Caliciviruses are a well-established cause of respiratory, vesicular and hemorrhagic diseases in animals. In addition, these viruses are an important cause of enteric diseases in humans. Recently, molecular analysis of several bovine enteric calicivirus isolates indicated that they are genetically close to human enteric calicivirus. To investigate...
Article
Full-text available
The aim of our study was to determine whether the severity of rotavirus gastroenteritis may be related to the different characteristics of infecting viral strains. The severity of clinical symptoms in 401 children with acute rotavirus gastroenteritis was assessed using a scoring system for frequency and duration of vomiting, diarrhea, and fever, as...
Article
Full-text available
A seminested PCR typing assay has been extended to identify rotavirus strains with the P[14] genotype. The specificity of the method was confirmed by Southern hybridization and by restriction analysis with the enzyme AluI. One out of four human rotavirus (HRV) strains with unusual subgroup-electropherotype linkage but none out of 50 HRV strains wit...
Article
108 rotavirus strains obtained from children with diarrhea hospitalized in Palermo, Italy, in the years 1990-1994, were examined by seminested PCR to study the relative frequency and distribution of the four most common alleles of the gene 4. Such strains were selected from 344 human rotavirus strains recovered in palermo during those years after c...
Article
Full-text available
A case of chronic intestinal infection due to adenovirus type 40 lasting for 13 months in a patient with AIDS is described. Adenovirus particles were detected by electron microscopy in biopsy samples taken from the duodenum 3 months after the onset of diarrhoea. The virus was identified as adenovirus type 40 in stool samples by ELISA monoclonal ant...
Article
To examine the role of enteric adenoviruses (Ad40 and Ad41) in children with acute gastroenteritis, we evaluated 273 children with diarrhoea and 137 without enteric symptoms in Palermo, Italy, during an 8-month period. Stools were tested by two home-made monoclonal-based ELISAs to detected genus-specific adenovirus antigen and to type Ad40 and Ad41...
Article
Polyacrylamide gel electrophoresis of nucleic acid extracted from stool samples of diarrhoeic children revealed in 3 out of 690 (0.43%) specimens two electrophoretic bands with a migration pattern characteristic of picobirnavirus ds-RNA. In none of the 92 control children were similar bands detected. No other potential enteric pathogens were found...
Article
During a measles outbreak, 112 serum specimens from 88 hospitalized patients were received in our laboratory for investigation of a morbilliform rash. These specimens (88 acute- and 24 convalescent-phase) were tested for the presence of measles-specific IgM antibodies by a capture EIA (enzyme immunoassay) using peroxidase-conjugated measles virus a...

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