Navegando por Orientadores "LINHARES, Alexandre da Costa"

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Análise molecular dos genes VP4, VP7 e NSP4 de rotavírus do tipo G1 circulantes em Belém e Marituba, Pará, Brasil, de 1982 a 2008
(Universidade Federal do Pará, 2011) SOARES, Luana da Silva; MASCARENHAS, Joana D'Arc Pereira; http://lattes.cnpq.br/5156164089432435; LINHARES, Alexandre da Costa; http://lattes.cnpq.br/3316632173870389
Rotaviruses are major viral agents of acute gastroenteritis and responsible for 36% of hospitalization for diarrhea among children less than five years of age, resulting in 453.000 deaths annually, mostly in developing countries. Rotavirus is a member of Reoviridae family, and its genome consists of 11 double-stranded RNA (dsRNA) which encode 12 proteins. G1 rotavirus is commonly detected in epidemiological investigations, occurring under different prevalence rates. The aim of this study was to analyze the VP4, VP7 and NSP4 diversity genetic of G1 rotavirus circulating in Belém and Marituba, Pará, Brazil, from 1982 to 2008. We selected 83 samples previously characterized as G1 type and submitted to RT-PCR. The samples were from seven studies conducted in IEC. It was possible amplification for 63 (75.9%) specimens. Lineages 1 (8/63, 12.7%), 2 (29/63, 46.0%), 3 (18/63, 28.6%) and 9 (8/63, 12.7%) of VP7 gene were detected. The sublineages 2E and 3A were co-predominant detected in 57.1% (36/63) of samples. Three amino acid substitutions (97 [D→E], 147 [S→N] and 218 [I→V]) were observed in VP7 antigenic regions (A, B and C) in samples of 1, 2 and 9 lineages. All samples showed P[8] specificity for VP4 gene and lineages 2 (21/63, 33.3%) and 3 (42/63, 66.7%) were detected. Two substitutions (35 [I→V] and 38 [S→G]) occurred in antigenic region of VP4 of samples analyzed. For NSP4 gene, all samples belonged to E1 type. Phylogenetic analysis of NSP4 gene revealed that occurred changes in nucleotide positions 47 (C→T) and 101 (T→C), resulting in amino acid substitutions at positions 16 (S→P) and 34 (L → P) in all samples and 9 specimens displayed amino acid substitution in NSP4 toxicity residue (aa 131). This study allowed us to broaden our understanding about genetic diversity and circulation of G1 variants and represents the first molecular epidemiology analyze of this genotype in Brazil corroborating the high heterogeneity of this genotype.
Acesso aberto (Open Access)
Caracterização antigênica e molecular de amostras de rotavírus do tipo G1, obtidas de crianças participantes de estudos em gastroenterites virais, no período de 1982 a 2003, em Belém, Pará, Brasil
(Universidade Federal do Pará, 2006-07-03) SOARES, Luana da Silva; MASCARENHAS, Joana D'Arc Pereira; http://lattes.cnpq.br/5156164089432435; LINHARES, Alexandre da Costa; http://lattes.cnpq.br/3316632173870389
Infant mortality remains an important problem of public health worldwide, mainly in developing countries. Of more than the 50 etiologic agents implied in this disease, rotavirus causes 111 million episodes of diarrhoea, resulting in more than 600,000 deaths among children less than five years, of which 82% are notified in the poorest countries of the world. This study aimed at the antigenic and molecular characterization of G1 rotavirus strains among children participanting of viral gastroenteritis studies, carried out from 1982 to 2003, in Belém, Pará, Brazil. One hundred and forty-eight specimens of G1 rotavirus were analyzed in the present investigation. Overall, the prevalence of the G1 type was of 41.3%, being that frequencies of this genotype through studies ranged from 11.0% to 67.6%. Eletropherotypes, G serotypes and P genotypes characterization of G1 rotavirus occurred in frequencies of 78.4%, 89.9% and 87.8%, respectively. Three long eletropherotypes varieties were identified, being that the L1 variety was found frequently (79.3%). The G1, G9 and G1+G4 serotypes were detected in 88.0%, 9.8% and 2.2% of the specimens, respectively. Mixed infection by G1+G4 genotype was detected in one sample. The prevalent binary combination was P[8],G1, being responsible for 72.3% of the cases. Mixed infections circulated in percentage of 20.0%, including genotypes P[4]+P[8],G1, P[6]+P[8],G1, P[4]+P[6],G1, P[4]+P[6]+P[8],G1 and P[6]+P[8],G1+G4. The G1 genotype circulated among 2nd to 35th months of age and a highest number of cases was registered between 6 to 16 months of age. Clinical severity differences among G1 and other genotypes of rotavirus were not verified. The present analysis gathers pioneer findings in Brazil, allowing to extend the knowledge concerning the antigenic and molecular diversity of the infections by G1 rotavirus and these results will allow to understand the genetic complexity of such viral agents.
Acesso aberto (Open Access)
Caracterização sorológica e detecção molecular do HTLV em amostras de pacientes com distúrbios neurológicos no Estado do Pará, Brasil (1996-2005)
(Universidade Federal do Pará, 2006-07-07) LIMA, Telma Vitorina Ribeiro; LINHARES, Alexandre da Costa; http://lattes.cnpq.br/3316632173870389
Human T-lymphotropic virus tipe 1 is recognized as the etiologic agent of tropical spastic paraparesis/HTLV-1 associated myelopathy (TSP/HAM). A very similar clinical disease has been increasingly associated to HTLV-2, whose pathogenicity still requires further assessments. This transversal, retrospective epidemiological survey aimed to determine the prevalence of HTLV among individuals with neurological disturbances and further evaluate cases of inconclusive serology using molecular biology methods. The present study involved patients inhabitants of Pará State and/or admitted at health institutions of the and who were referred to the Virology Section of Instituto Evandro Chagas (IEC) by local doctors between January of 1996 and December 2005, to search for the presence of HTLV-1/2 serum antibodies. Of these patients 353 were selected, with age between 9 months and 79 years, who presented at least one signal or symptom of the Marsh’s Complex (1996), as well as had HTLV-1/2 positive serology at screening and confirmatory ELISA. The overall prevalence of HTLV antibodies by ELISA as 8,8% (31/353), with rates of 10,6% (19/179) and 6,9% (12/174) for female and male patients, respectively. Among HTLV-1/2 the 31 ELISA-positive patients it was noted that 15 (48.4%) of 31 had paresis (n = 8), parestesis (n = 5), and paraplegia (n = 3). Of these 31 HTLV ELISA positive patients, 25 could be submitted to WB for assessment of viral types, which were distributed as follow: 80% (20/25) were HTLV-1, 12% (3/25) were HTLV-2, one case was of HTLV-1+HTLV-2 infection (4%), and serum from one patient yielded an indeterminate profile (4%). Only 14 of these 25 patients could be re-localised for collection of an additional sample for molecular analysis. It was observed that 78.6% of samples typed by WB had the proviral TAX region successfully amplified by nested-PCR. In addition, types were confirmed as based on results obtained from the amplification of the POL region using real-time PCR; this denoted good specificity and sensitivity of the WB used in this study. The sample defined as HTLV-1+HTLV-2 infection by WB was amplified in its TAX region but real time PCR confirmed HTLV-1 infection only. The patient with WB indeterminate profile and one of samples typed as HTLV-2 by WB were amplified by nested-PCR but the real time PCR was negative for HTLV-1 and HTLV-2 in both samples. One patient presenting clinical manifestations of crural myalgia and parestesia with duration of about 7 years reacted HTLV-2-positive by both WB and real-time PCR, a denoting a clear HTLV-2- related chronic myelopathy. This study has identified a case of possible vertical transmission in two distinct situations: a patient whose mother presented antibodies for HTLV-1 by WB and two sisters who reacted HTLV-1-positive by WB and real-time PCR. Although of epidemiological relevance, results from this study warrant further and broader analyses concerning the molecular epidemiology of HTLV types and subtypes HTLV. In addition, a more complete clinical assessment of neurological symptoms should be further performed, in order to better characterise cases of HTLV-related chronic myelopathy in our region.
Acesso aberto (Open Access)
Eficácia e segurança de uma vacina oral de rotavírus humano atenuado contra gastroenterite grave por rotavírus, durante os primeiros dois anos de vida em crianças em Belém, Pará, Brasil
(Universidade Federal do Pará, 2009) JUSTINO, Maria Cleonice Aguiar; ARAÚJO, Eliete da Cunha; http://lattes.cnpq.br/5906453187927460; LINHARES, Alexandre da Costa; http://lattes.cnpq.br/3316632173870389
Rotaviruses are recognised as the leading cause of severe gastroenteritis in children aged less than five years in both developed and developing countries, with highest incidence rates between 6 and 24 months of life. On a global scale, recent estimates indicate that annually rotaviruses cause at least 500,000 deaths. A large phase III clinical trial was undertaken in 11 Latin American countries and Finland with an attenuated, human-derived vaccine strain, including recruitment of more than 63,000 children. This was a randomised, double-blind, placebo-controlled trial in which more than 63,000 infants were randomly assigned to receive two oral doses of either RIX4414 or placebo at a proportion of 1:1. The main purposed of this study was to evaluate both protective efficacy and safety of RIX4414. As part of the original study, 3,218 children were enrolled in Belém, Pará, to whom two doses of either vaccine or placebo were administered at 2 and 4 months of age. A subset of infants (n = 653) was evaluated throughout 1 – 2 years in order to assess efficacy of RIX4414 vaccine. Overall, 37 gastroenteritis episodes of severe rotavirus gastroenteritis were recorded of which 75.6% (28/37) and 24% (9/37) in the placebo and vaccine recipients, respectively. The level of rotavirus vaccine protection was higher [83% (CI95% 22 – 96)] against very severe rotavirus gastroenteritis, yielding a ≥ 15 score as calculated with a 20-point Ruuska & Vesikari scale. The cumulative hazard of a first episode of severe gastroenteritis was about four-fold lower in the vaccine group throughout the 2-years’ efficacy period, as compared to the placebo group. The protection rates against severe gastroenteritis caused by G1- and- non-G1 serotypes were 51% (CI95% -30-81) and 82% (CI95% 37-95), respectively, denoting efficacies against rotavirus strains both homologous and heterologous to the vaccine strain. Of importance, the vaccine afforded significant protection [93% (CI95%47-99)] against G9 serotype which has been regarded as a globally emergent strain, besides of being related to more severe gastroenteritis. Also reflecting a vaccine efficacy, there was a significant reduction, by 35.3% (CI95% 11.6-52.9), in the rate of allcause hospitalisation for gastroenteritis, a finding of potential major public health impact. With regards to safety of RIX4414 vaccine, there were no overall statistically significant differences when the rates of serious adverse events were compared for vaccine group and placebo group. No cases of intussusception were reported during the entire follow-up period, through broad and active surveillance in paediatric clinics in the study area. Results obtained in this study confirm previous findings from worldwide several multi-centric trials that sustain both protective efficacy and safety of RIX4414 when administered in a 2-dose schema to healthy infants.
Acesso aberto (Open Access)
Epidemiologia molecular das infecções por rotavírus G2 ao longo de 16 anos (1992 a 2008) na região amazônica, Brasil
(Universidade Federal do Pará, 2010-07-05) OLIVEIRA, Alessilva do Socorro Lima de; LINHARES, Alexandre da Costa; http://lattes.cnpq.br/3316632173870389
In Brazil it is estimated that rotavirus causes 3,352,053 episodes of diarrhea, 655 853 visits to emergency rooms, 92,453 hospitalizations and 850 deaths involving children under 5 years of age. Rotavirus belongs to the family Reoviridae, genus Rotavirus. The viral particle consists of three concentric layers of protein and the viral genome of 11 segments making up a double-stranded RNA. Currently, 23 G genotypes and 31 P genotypes. have been recognized. Among the G genotypes detected so far, G2 represents one of the most important and it is usually associated with the genotype P [4]. Over the past three years it has been observed on a continental scale the reemergence of genotype G2, throughout the years following the introduction of universal rotavirus vaccination, particularly in Brazil. This study aimed at the molecular characterization of samples of G2 strains obtained from children participating in several studies on rotavirus gastroenteritis in the Amazon region, Brazil, from 1992 to 2008. We selected 53 rotavirus G2 samples which were sequenced for VP4 and 38 samples for VP7. These samples were genotyped by RTPCR and its products being purified, quantified and sequenced. Samples were also subjected to electrophoresis of RNA segments. The obtained sequences of VP4 and VP7 genes were aligned and edited using the program Bioedit (v.6.05) and compared with other sequences registered in the RV gene bank using the BLAST program. The phylogenetic tree was made using the program Mega 2.1. Of the total 53 samples sequenced for the VP7 gene, phylogenetic analysis revealed two lineages (II and III) and three sublineages (IIa, IIc, IId) that circulated in different periods in the population. Samples of sub-lineages IIa and IIc showed mutation at amino acid position 96(Asp/Asn). This modification may result in a conformational change of epitopes recognized by neutralizing antibodies. The G2 strains that circulated in Belém were identical to those circulating in other states in the Amazon region which were included in the study. The VP[4] gene was sequenced in the region of VP8*, yielding 36 which-belonged to genotype P[4] and tree to P[6] we could identify two strains: P[4]-4, occurring during 1998-2000 and the P[4]-5 during 1993-1994 and 2006-2008 periods. Our findings sustain recent findings indicating a worldwide reemergence of G2 genotypes of variant IIc, which were established in the population in combination with genotype P[4]-5. In our study, the high homology among G2 strains in various states suggests that detected mutations have even surpassed geographical and temporal barriers.
Acesso aberto (Open Access)
Pesquisa epidemiológica e molecular do vírus respiratório sincicial humano (VSRH) em amostras de pacientes hospitalizados com pneumonia, na cidade de Belém
(Universidade Federal do Pará, 2011-11-17) LAMARÃO, Letícia Martins; LINHARES, Alexandre da Costa; http://lattes.cnpq.br/3316632173870389
Childhood pneumonia and bronchiolitis is a leading cause of illness and death in young children worldwide with Respiratory Syncytial Virus (RSV) as the main viral cause. RSV has been associated with annual respiratory disease outbreaks and bacterial co-infection has also been reported. This study is the first RSV study in young children hospitalized with community-acquired pneumonia (CAP) in Belém city, Pará (Northern Brazil). It had the objective of determining the prevalence of RSV infection and evaluating the patients’ clinical and epidemiological features. Methods. We conducted a prospective study across eight hospitals from November 2006 to October 2007. In this study, 1,050 nasopharyngeal aspirate samples were obtained from hospitalized children up to the age of three years with CAP, and tested for RSV antigen by direct immunofluorescence assay and by Reverse Transcription Polymerase Chain Reaction (RT-PCR) for RSV subtype identification. Levels of C-reactive protein (CRP) and results of bacterial infection were also obtained. Results. RSV infection was diagnosed in 243 (23.1%) children. The mean age of the RSV-positive group was lower than the RSV-negative group (12.1 months vs 15.5 months, both ranged 1-36 months, p<0.001) whereas gender distribution was similar. The RSV-positive group showed lower CRP mean levels when compared to the RSV-negative group (15.3 vs 24.0 mg/dL, p<0.05). Radiological findings showed that 54.2% of RSV-positive group and 50.3% of RSV-negative group had interstitial infiltrate. Bacterial infection was identified predominantly in the RSV-positive group (10% vs 4.5%, p<0.05). Rhinorrhea and nasal obstruction were predominantly observed in the RSV-positive group. A co-circulation of subtypes A and B was noted, with a predominance of subtype B (209/227). Multivariate analysis revealed that age under 1 year (p<0.015), CRP levels under 48 mg/dL (p<0.001) and bacterial co-infection (p<0.032) were independently associated with the presence of RSV as opposed to RSV-negative group, and in analyze of symptoms, nasal obstruction were independently associated with RSV-positive group (p<0.001). Conclusion. The present study highlights the relevance of RSV infection in hospitalized cases of CAP in our region; our findings warrant the conduct of further investigations which can help design strategies for controlling the disease.