Phylodynamics and Dispersal of HRSV Entails Its Permanence in the General Population in between Yearly Outbreaks in Children

Background: Human respiratory syncytial virus (HRSV) is one of the major etiologic agents of respiratory tract infections among children worldwide. Methodology/Principal Findings: Here through a comprehensive analysis of the two major HRSV groups A and B (n = 1983) which comprise of several genotypes, we present a complex pattern of population dynamics of HRSV over a time period of 50 years (1956-2006). Circulation pattern of HRSV revealed a series of expansions and fluctuations of co-circulating lineages with a predominance of HRSVA. Positively selected amino acid substitutions of the G glycoprotein occurred upon population growth of GB3 with a 60-nucleotide insertion (GB3 Insert), while other genotypes acquired substitutions upon both population growth and decrease, thus possibly reflecting a role for immune selected epitopes in linkage to the traced substitution sites that may have important relevance for vaccine design. Analysis evidenced the co-circulation and predominance of distinct HRSV genotypes in Brazil and suggested a year-round presence of the virus. In Brazil, GA2 and GA5 were the main culprits of HRSV outbreaks until recently, when the GB3 Insert became highly prevalent. Using Bayesian methods, we determined the dispersal patterns of genotypes through several inferred migratory routes. Conclusions/Significance: Genotypes spread across continents and between neighboring areas. Crucially, genotypes also remained at any given region for extended periods, independent of seasonal outbreaks possibly maintained by re-infecting the general population.FAPESPFAPESP [Nu 00/4205-6

Positive Selection Results in Frequent Reversible Amino Acid Replacements in the G Protein Gene of Human Respiratory Syncytial Virus

Human respiratory syncytial virus (HRSV) is the major cause of lower respiratory tract infections in children under 5 years of age and the elderly, causing annual disease outbreaks during the fall and winter. Multiple lineages of the HRSVA and HRSVB serotypes co-circulate within a single outbreak and display a strongly temporal pattern of genetic variation, with a replacement of dominant genotypes occurring during consecutive years. In the present study we utilized phylogenetic methods to detect and map sites subject to adaptive evolution in the G protein of HRSVA and HRSVB. A total of 29 and 23 amino acid sites were found to be putatively positively selected in HRSVA and HRSVB, respectively. Several of these sites defined genotypes and lineages within genotypes in both groups, and correlated well with epitopes previously described in group A. Remarkably, 18 of these positively selected tended to revert in time to a previous codon state, producing a “flip-flop” phylogenetic pattern. Such frequent evolutionary reversals in HRSV are indicative of a combination of frequent positive selection, reflecting the changing immune status of the human population, and a limited repertoire of functionally viable amino acids at specific amino acid sites

Global demographic history of HRSV genotypes.

<p>Bayesian skyline plots of complete HRSV sequences of HRSVA (n = 1203) and HRSVB (n = 780). The <i>y</i>-axis represents a measure of relative genetic diversity presented as <i>Ne.g</i> reflecting the change in effective population (a surrogate for number of infections) over time for the complete set of HRSV sequences for HRSVA (n = 1204) and HRSVB (n = 778). The dotted lines define the likelihood bounds corresponding to a 95% confidence interval (CI). (…) - Upper and lower limits for HRSVA; (—) - Upper and lower limits for HRSVB. The arrow represents a shift in dynamics between HRSVA and HRSVB.</p

Epidemiology and population dynamics of HRSV in São Paulo.

<p>Bayesian skyline plots of HRSV genotypes prevalent in São Paulo (top) and seasonal distribution of HRSV cases in São Paulo during the 1995–2005 seasons are shown in the <i>x</i>-axis. GA1, GA3 GA7 and GB4 were excluded from the BSL analysis because of small sample size (n<10). The <i>y</i>-axis (on the left) represents a measure of relative genetic diversity presented as <i>Ne.g</i> reflecting the change in effective number of infections over time; where <i>g</i> is the average generation time. The <i>y</i>-axis (on the right) represents the number of samples in the study. (-) - Number of total samples collected during the period. (-) - Number of all HRSV positive cases identified with monoclonal antibodies and molecular characterization.</p

Population dynamics and genetic diversity of HRSV.

<p>A) Bayesian skyline plots of HRSVA genotypes B) Bayesian skyline plots of HRSVB genotypes. Positively selected amino acid substitution sites are represented as previously described by Botosso et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041953#pone.0041953-Botosso1" target="_blank">[48]</a>. The <i>y</i>-axis represents a measure of relative genetic diversity presented as <i>Ne.g</i> reflecting the change in effective number of infections over time.</p

Clinical patterns and seasonal trends in respiratory syncytial virus hospitalizations in São Paulo, Brazil

The respiratory viruses are recognized as the most frequent lower respiratory tract pathogens for infants and young children in developed countries but less is known for developing populations. The authors conducted a prospective study to evaluate the occurrence, clinical patterns, and seasonal trends of viral infections among hospitalized children with lower respiratory tract disease (Group A). The presence of respiratory viruses in children's nasopharyngeal was assessed at admission in a pediatric ward. Cell cultures and immunofluorescence assays were used for viral identification. Complementary tests included blood and pleural cultures conducted for bacterial investigation. Clinical data and radiological exams were recorded at admission and throughout the hospitalization period. To better evaluate the results, a non- respiratory group of patients (Group B) was also constituted for comparison. Starting in February 1995, during a period of 18 months, 414 children were included- 239 in Group A and 175 in Group B. In Group A, 111 children (46.4%) had 114 viruses detected while only 5 children (2.9%) presented viruses in Group B. Respiratory Syncytial Virus was detected in 100 children from Group A (41.8%), Adenovirus in 11 (4.6%), Influenza A virus in 2 (0.8%), and Parainfluenza virus in one child (0.4%). In Group A, aerobic bacteria were found in 14 cases (5.8%). Respiratory Syncytial Virus was associated to other viruses and/or bacteria in six cases. There were two seasonal trends for Respiratory Syncytial Virus cases, which peaked in May and June. All children affected by the virus were younger than 3 years of age, mostly less than one year old. Episodic diffuse bronchial commitment and/or focal alveolar condensation were the clinical patterns more often associated to Respiratory Syncytial Virus cases. All children from Group A survived. In conclusion, it was observed that Respiratory Syncytial Virus was the most frequent pathogen found in hospitalized children admitted for severe respiratory diseases. Affected children were predominantly infants and boys presenting bronchiolitis and focal pneumonias. Similarly to what occurs in other subtropical regions, the virus outbreaks peak in the fall and their occurrence extends to the winter, which parallels an increase in hospital admissions due to respiratory diseases.Os vírus respiratórios são reconhecidos como os mais frequentes patógenos do trato respiratório inferior para lactentes e crianças de idade reduzida em países desenvolvidos, mas o conhecimento sobre este fato é menor nos países em desenvolvimento.Os autores realizaram um estudo prospectivo para avaliar a ocorrência, os padrões clínicos e a sazonalidade das infecções virais entre as crianças hospitalizadas com doença do trato respiratório inferior (grupo A). A presença de vírus respiratórios na nasofaringe das crianças foi avaliada à admissão em uma enfermaria de pediatria. A cultura celular e a imunofluorescência foram utilizadas para identificação viral. Exames complementares incluiram culturas de sangue e líquido pleural para detecção de bactérias. Dados clínicos e exames radiológicos foram anotados na admissão e durante o período de internação. Para avaliar adequadamente os resultados foi constituído um grupo sem doença respiratória para comparação. Com início em fevereiro de 1995, durante um período de 18 meses, 414 crianças foram incluídas - 239 no grupo A e 175 no grupo B. No grupo A, 111 crianças (46,4%) tinham vírus enquanto somente 5 (2,9%) apresentavam vírus no grupo B. O Vírus Respiratório Sincicial foi detectado em 100 crianças do grupo A (41,8%), o Adenovírus em 11 (4,6%), o vírus Influenza em 2 (0,8%), e o Parainfluenza em uma criança (0,4%). No grupo A as bactérias foram encontradas em 14 casos (5,8%). O Vírus Respiratório Sincicial estava associado a outro vírus ou bactéria em seis casos. Ocorreram dois surtos de Vírus Respiratório Sincicial, com pico em maio e junho. Todas as crianças acometidas por este vírus tinham idade inferior a 3 anos, na sua maior parte menos de um ano de idade. O acometimento bronquial episódico e difuso e/ou a condensação alveolar focal, foram os padrões clínicos mais frequentemente associados aos casos de infecção pelo Vírus Respiratório Sincicial. Todas as crianças do grupo A sobreviveram. Em conclusão, foi observado que o Vírus Respiratório Sincicial foi o patógeno mais frequentemente encontrado em crianças hospitalizadas por doença respiratória grave. As crianças afetadas eram predominantemente lactentes do sexo masculino com bronquiolite e pneumonias focais. De modo similar ao que ocorre em outras regiões subtropicais os surtos do vírus têm pico no outono, extendem-se ao inverno, e se acompanham de um aumento nas internações hospitalares por doença respiratória

Dynamics of encapsulated hepatitis B surface antigen:A combined neutron spectroscopy and thermo-analysis study

As a consequence of its ordered pore architecture, mesoporous SBA-15 offers new possibilities for incorporating biological agents. Considering its applicability in oral vaccination, which shows more beneficial features when compared with parenteral vaccines, SBA-15 is also seen as a very promising adjuvant to carry, protect, and deliver entrapped antigens. Recent studies have shown several remarkable features in the immunization of hepatitis B, a viral disease transmitted mainly through blood or serum transfer. However, the surface antigen of the hepatitis B virus, HBsAg, is too large to fit inside the SBA-15 matrix with mean pore diameter around 10 nm, thus raising the question of how SBA-15 can protect the antigen. In this work, thermal analysis combined with neutron spectroscopy allowed us to shed light on the interactions between HBsAg and SBA-15 as well as on the role that these interactions play in the efficiency of this promising oral vaccination method. This information was obtained by verifying how the dynamic behaviour of the antigen is modified under confinement in SBA-15, thus also establishing an experimental method for verifying molecular dynamics simulations

Respiratory syncytial virus epidemic periods in an equatorial city of Brazil

Submitted by Sandra Infurna ([email protected]) on 2017-01-24T14:14:17Z No. of bitstreams: 1 marilda_siqueira_etal_IOC_2013.pdf: 274921 bytes, checksum: baf4e66faf10e03f01d0baa4bacf33f4 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2017-01-24T14:23:30Z (GMT) No. of bitstreams: 1 marilda_siqueira_etal_IOC_2013.pdf: 274921 bytes, checksum: baf4e66faf10e03f01d0baa4bacf33f4 (MD5)Made available in DSpace on 2017-01-24T14:23:30Z (GMT). No. of bitstreams: 1 marilda_siqueira_etal_IOC_2013.pdf: 274921 bytes, checksum: baf4e66faf10e03f01d0baa4bacf33f4 (MD5) Previous issue date: 2013Universidade Federal do Ceará. Fortaleza, CE, Brasil.Universidade Federal do Ceará. Fortaleza, CE, Brasil.Universidade Federal do Ceará. Fortaleza, CE, Brasil.Universidade Federal do Ceará. Fortaleza, CE, Brasil.Universidade Federal do Ceará. Fortaleza, CE, Brasil.Universidade Federal do Ceará. Fortaleza, CE, Brasil.Instituto Butantan. São Paulo, SP, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ. Brasil.Universidade de São Paulo. São Paulo, SP, Brasil.Universidade de São Paulo. São Paulo, SP, Brasil.Universidade de São Paulo. São Paulo, SP, Brasil.Universidade de São Paulo. São Paulo, SP, Brasil.Characterization of the human respiratory syncytial virus (HRSV) season at the local level has important implications for appropriate decisions on the time period for administration of specific prophylaxis

Yellow Fever Virus DNA in Urine and Semen of Convalescent Patient, Brazil

Yellow fever virus RNA is usually detected in blood of infected humans. We detected virus RNA in urine and semen samples from a convalescent patient. A complete virus genome was sequenced for an isolate from a urine sample. This virus had a South American I genotype and unique synapomorphic changes