167 research outputs found

    Antigenic variability in Neuraminidase protein of Influenza A/H3N2 vaccine strains (1968 – 2009)

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    Antigenic drift and shift involving the surface proteins of Influenza virus gave rise to new strains that caused epidemics affecting millions of people worldwide over the last hundred years. Variations in the membrane proteins like Hemagglutinin (HA) and Neuraminidase (NA) necessitates new vaccine strains to be updated frequently and poses challenge to effective vaccine design. Though the HA protein, the primary target of the human immune system, has been well studied, reports on the antigenic variability in the other membrane protein NA are sparse. In this paper we investigate the molecular basis of antigenic drift in the NA protein of the Influenza A/H3N2 vaccine strains between 1968 and 2009 and proceed to establish correlation between antigenic drift and antigen-antibody interactions. Sequence alignments and phylogenetic analyses were carried out and the antigenic variability was evaluated in terms of antigenic distance. To study the effects of antigenic drift on the protein structures, 3D structure of NA from various strains were predicted. Also, rigid body docking protocol has been used to study the interactions between these NA proteins and antibody Mem5, a 1998 antibody

    Randomised controlled trial comparing daily VerSus depot vitamin D3 therapy in 0-16-year-old newly settled refugees in Western Australia over a period of 40 weeks

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    Vitamin D deficiency is highly prevalent in newly settled refugees in Western Australia (WA). If adherence to daily vitamin D therapy is problematic, depot therapy is a therapeutic alternative. The aim of this studywas to compare daily versus depot treatment and factors influencing the therapeutic outcome. Newly settled refugees (n = 151) with 25(OH)D levels less than 78 nmol/L were randomised to receive daily or depot vitamin D therapy with eight weekly interval follow up to 40 weeks. Biochemical and clinical parameters were collected at each visit. Generalized LinearMixedModels (GLMM) examined the longitudinal changes over time controlling for confounders including age, gender, treatment arm, season, country of refuge/origin and sun exposure score. Participants were aged 5.5 months to 16.0 years (75 males, 83 females). Both treatment groups achieved vitamin D sufficiency. The daily treatment group had significantly higher 25(OH)D levels at each visit post baseline and a higher proportion of participants with levels above 50 nmol/L at all time points. Time, treatment group, calcium and sun exposure score were significant predictors of 25(OH)D serum levels. Depot vitamin D therapy is an alternative to daily treatment in this at-risk group of children and adolescents in whom treatment adherence is problemati

    Genetic Characterization of the Influenza A Pandemic (H1N1) 2009 Virus Isolates from India

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    Background: The Influenza A pandemic H1N1 2009 (H1N1pdm) virus appeared in India in May 2009 and thereafter outbreaks with considerable morbidity and mortality have been reported from many parts of the country. Continuous monitoring of the genetic makeup of the virus is essential to understand its evolution within the country in relation to global diversification and to track the mutations that may affect the behavior of the virus. Methods: H1N1pdm viruses were isolated from both recovered and fatal cases representing major cities and sequenced. Phylogenetic analyses of six concatenated whole genomes and the hemagglutinin (HA) gene of seven more isolates from May-September 2009 was performed with reference to 685 whole genomes of global isolates available as of November 24, 2009. Molecular characterization of all the 8 segments was carried out for known pathogenic markers. Results: The first isolate of May 2009 belonged to clade 5. Although clade 7 was the dominant H1N1pdm lineage in India, both clades 6 and 7 were found to be co-circulating. The neuraminidase of all the Indian isolates possessed H275, the marker for sensitivity to the neuraminidase inhibitor Oseltamivir. Some of the mutations in HA are at or in the vicinity of antigenic sites and may therefore be of possible antigenic significance. Among these a D222G mutation in the HA receptor binding domain was found in two of the eight Indian isolates obtained from fatal cases. Conclusions: The majority of the 13 Indian isolates grouped in the globally most widely circulating H1N1pdm clade 7

    Genetic divergence of Chikungunya viruses in India (1963-2006) with special reference to the 2005-2006 explosive epidemic

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    Re-emergence of Chikungunya (CHIK), caused by CHIK virus, was recorded in India during 2005-2006 after a gap of 32 years, causing 1.3 million cases in 13 states. Several islands of the Indian Ocean reported similar outbreaks in the same period. These outbreaks were attributed to the African genotype of CHIK virus. To examine relatedness of the Indian isolates (IND-06) with Reunion Island isolates (RU), full-genome sequences of five CHIK virus isolates representative of different Indian states were determined. In addition, an isolate obtained from mosquitoes in the year 2000 (Yawat-2000), identified as being of the African genotype, and two older strains isolated in 1963 and 1973 (of the Asian genotype), were sequenced. The IND-06 isolates shared 99.9 % nucleotide identity with RU isolates, confirming involvement of the same strain in these outbreaks. The IND-06 isolates shared 98.2 % identity with the Yawat-2000 isolate. Of two crucial substitutions reported for RU isolates in the E1 region, M269V was noted in the Yawat-2000 and IND-06 isolates, whereas D284E was seen only in the IND-06 isolates. The A226V shift observed with the progression of the epidemic in Reunion Island, probably associated with adaptation to the mosquito vector, was absent in all of the Indian isolates. Three unique substitutions were noted in the IND-06 isolates: two (T128K and T376M) in the Nsp1 region and one (P23S) in the capsid protein. The two Asian strains showed 99.4 % nucleotide identity to each other, indicating relative stability of the virus. No evidence of recombination of the Asian and African genotypes, or of positive selection was observed. The results may help in understanding the association, if any, of the unique mutations with the explosive nature of the CHIK outbreak

    A unique influenza A (H5N1) virus causing a focal poultry outbreak in 2007 in Manipur, India

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    <p>Abstract</p> <p>Background</p> <p>A focal H5N1 outbreak in poultry was reported from Manipur, a north-eastern state, of India, in 2007. The aim of this study was to genetically characterize the Manipur isolate to understand the relationship with other H5N1 isolates and to trace the possible source of introduction of the virus into the country.</p> <p>Results</p> <p>Characterization of the complete genome revealed that the virus belonged to clade 2.2. It was distinctly different from viruses of the three EMA sublineages of clade 2.2 but related to isolates from wild migratory waterfowl from Russia, China and Mongolia. The HA gene, had the cleavage site GERRRRKR, earlier reported in whooper swan isolates from Mongolia in 2005. A stop codon at position 29 in the PB1-F2 protein could have implications on the replication efficiency. The acquisition of polymorphisms as seen in recent isolates of 2005–07 from distinct geographical regions suggests the possibility of transportation of H5N1 viruses through migratory birds.</p> <p>Conclusion</p> <p>Considering that all eight genes of the earlier Indian isolates belonged to the EMA3 sublineage and similar strains have not been reported from neighbouring countries of the subcontinent, it appears that the virus may have been introduced independently.</p

    Haemophilus ducreyi as a cause of skin ulcers in children from a yaws-endemic area of Papua New Guinea: a prospective cohort study

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    Background Skin infections with ulceration are a major health problem in countries of the south Pacifi c region. Yaws, caused by Treponema pallidum subspecies pertenue and diagnosed by the presence of skin ulcers and a reactive syphilis serology, is one major cause, but this infection can be confused clinically with ulcers due to other causative agents. We investigated T pallidum pertenue and another bacterium known to cause skin infections in the Pacifi c islands— Haemophilus ducreyi—as causes of skin ulceration in a yaws-endemic region. Additionally, we identifi ed specifi c signs and symptoms associated with these causative agents of cutaneous ulcers and compared these fi ndings with laboratory-based diagnoses. Methods We did a prospective cohort study of fi ve yaws-endemic villages (total population 3117 people) during a yaws elimination campaign in Papua New Guinea in April, 2013. We enrolled all consenting patients with chronic moist or exudative skin ulcers. We undertook a detailed dermatological assessment, syphilis serology, and PCR on lesional swabs to detect the presence of T pallidum pertenue and H ducreyi. Patients with PCR-confi rmed bacterial infections were included in a comparative analysis of demographics and clinical features. Findings Full outcome data were available for 90 people with skin ulcers. Of these patients, 17 (19%) had negative results in all molecular tests and were therefore excluded from the comparative analyses. A bacterial cause was identifi ed in 73 (81%) participants—either H ducreyi (n=42), T pallidum pertenue (yaws; n=19), or coinfection with both organisms (dual infection; n=12). The demographic characteristics of the patients infected with yaws and with H ducreyi were similar. Skin lesions in patients with yaws and in those with dual infection were larger than those in patients infected with H ducreyi (p=0·071). The lesions in patients with yaws and dual infection were more circular in shape (79% and 67%) than in those infected with H ducreyi (21%; p<0·0001); more likely to have central granulating tissue (90% and 67% vs 14%; p<0·0001); and more likely to have indurated edges (74% and 83% vs 31%; p=0·0003). The prevalence of reactive combined serology (positive T pallidum haemagglutination test and rapid plasmin reagin titre of ≥1:8) was higher in cases of yaws (63%) and dual infections (92%) than in H ducreyi infections (29%; p<0·0001). Interpretation In this yaws-endemic community, H ducreyi is an important and previously unrecognised cause of chronic skin ulceration. Reactive syphilis serology caused by latent yaws can occur in ulcers with the presence of H ducreyi alone. The introduction of PCR for ulcer surveillance could improve the accuracy of diagnosis in countries with yaws eradication campaigns

    Development of a transcript to record learner creativity and curiosity

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    Funded with generous support by the Jacobs Foundation, the ultimate goal of this project was to develop transcripts to track learner progress in the domains of creativity and curiosity. To support this overarching goal, the research team sought to define creativity and curiosity in language that would resonate with learners and teachers and that would be appropriate across numerous cultural settings. The result of the project is a series of prototype materials and resources, specifically: literature reviews, frameworks, enabling environment summaries, reflective quizzes and transcripts. Based on insights from the literature reviews, the researchers developed frameworks to define the constructs of creativity and curiosity and to offer resources that learners can refer to in class. The researchers also hypothesize that school context is important and that schools and teachers can provide an enabling environment to support learners to be more creative and curious. Lastly, the research team propose transcripts for each domain, which are designed to balance learner reflection and teacher verification. Further research is required to validate these resources before schools implement them with the aim of evidencing student growth in creativity and curiosity
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