Transmission dynamics of novel influenza A/H1N1 2009 outbreak in a residential school in India

Transmission dynamics of an outbreak of novel influenza A/H1N1 (2009) in June-July 2009 in a residential school in Maharashtra, India has been studied. A mathematical model of the type susceptible-exposedinfectious- asymptomatic-recovered has been adopted for the purpose. Analyses of epidemiological data revealed that close clustering within population resulted in high transmissibility with basic reproduction number R0 = 2.61 and transmission rate (β) being 0.001566. Model has successfully described the dynamics of transmission in a residential school setting and helped in ascertaining the epidemiological parameters for asymptomatic cases and the effectiveness of the control measures. Our study presents a framework for studying similar outbreaks of influenza involving clustered populations

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

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

Comparison of etiology of sporadic acute and fulminant viral hepatitis in hospitalized patients in Pune, India during 1978-81 and 1994-97

Objective: To determine and compare the etiology of sporadic acute and fulminant viral hepatitis in two groups of patients 16 years apart. Methods: Serologic diagnostic tests for hepatitis A, B, C, D and E, and cytomegalovirus infection were carried out in 276 patients during 1994-1997 (Group A) and 206 patients during 1978-1981 (Group B). Results: Among children, hepatitis A virus was the major etiologic agent (81.6% in Group A and 51.4% in Group B), followed by hepatitis E virus (12.2%, 46.4%) and hepatitis B virus (5.4%, none). Among adults, hepatitis E virus was the main causative agent (42.4% in Group A and 71.2% in Group B) followed by HBV (28%, 25.5%) and hepatitis A virus (10.6%, 3.5%). Delta hepatitis was found only in Group A. No viral cause was found in 25% of patients in Group A and 13.5% patients in Group B. Conclusions: Hepatitis E virus is a major cause of sporadic acute and fulminant hepatitis. There has been an increase in hepatitis A in adults who developed fulminant hepatic failure. Our data points to the emergence of hepatitis A in adults and emergence of delta virus infection. Hepatitis C virus was unimportant in causing sporadic hepatitis

Surveillance in eastern India (2007-2009) revealed reassortment event involving ns and PB1-F2 gene segments among co-circulating influenza a subtypes

<p>Abstract</p> <p>Background</p> <p>Influenza A virus encodes for eleven proteins, of which HA, NA, NS1 and PB1-F2 have been implicated in viral pathogenicity and virulence. Thus, in addition to the HA and NA gene segments, monitoring diversity of NS1 and PB1-F2 is also important.</p> <p>Methods</p> <p>55 out of 166 circulating influenza A strains (31 H1N1 and 24 H3N2) were randomly picked during 2007-2009 and NS and PB1-F2 genes were sequenced. Phylogenetic analysis was carried out with reference to the prototype strains, concurrent vaccine strains and other reference strains isolated world wide.</p> <p>Results</p> <p>Comparative analysis of both nucleotide and deduced amino acid sequences, revealed presence of NS gene with A/PR/8/34(H1N1)-like mutations (H4N, Q21R, A22V, K44R, N53D, C59R, V60A, F103S and M106I) in both RNA-binding and effector domain of NS1 protein, and G63E, the HPAI-H5N1-like mutation in NEP/NS2 of five A/H1N1 strains of 2007 and 2009. NS1 of other A/H1N1 strains clustered with concurrent A/H1N1 vaccine strains. Of 31 A/H1N1 strains, five had PB1-F2 similar to the H3N2 strains; six had non-functional PB1-F2 protein (11 amino acids) similar to the 2009 pandemic H1N1 strains and rest 20 strains had 57 amino acids PB1-F2 protein, similar to concurrent A/H1N1 vaccine strain. Interestingly, three A/H1N1 strains with H3N2-like PB1-F2 protein carried primitive PR8-like NS gene. Full gene sequencing of PB1 gene confirmed presence of H3N2-like PB1 gene in these A/H1N1 strains.</p> <p>Conclusion</p> <p>Overall the study highlights reassortment event involving gene segments other than HA and NA in the co-circulating A/H1N1 and A/H3N2 strains and their importance in complexity of influenza virus genetics. In contrast, NS and PB1-F2 genes of all A/H3N2 eastern India strains were highly conserved and homologous to the concurrent A/H3N2 vaccine strains suggesting that these gene segments of H3N2 viruses are evolutionarily more stable compared to H1N1 viruses.</p

Pandemic influenza A(H1N1) 2009 outbreak in a residential school at Panchgani, Maharashtra, India

Background &amp; objectives: An outbreak of influenza was investigated between June 24 and July 30, 2009 in a residential school at Panchgani, Maharashtra, India. The objectives were to determine the aetiology, study the clinical features in the affected individuals and, important epidemiological and environmental factors. The nature of public health response and effectiveness of the control measures were also evaluated. Methods: Real time reverse transcriptase polymerase chain reaction was performed on throat swabs collected from 82 suspected cases to determine the influenza types (A or B) and sub-types [pandemic (H1N1) 2009, as well as seasonal influenza H1N1, H3N2]. Haemagglutination inhibition assay was performed on serum samples collected from entire school population (N = 415) to detect antibodies for pandemic (H1N1) 2009, seasonal H1N1, H3N2 and influenza B/Yamagata and B/Victoria lineages. Antibody titres ≥ 10 for pandemic (H1N1) 2009 and ≥ 20 for seasonal influenza A and B were considered as positive for these viruses. Results: Clinical attack rate for influenza-like illness was 71.1 per cent (295/415). The attack rate for pandemic (H1N1) 2009 cases was 42.4 per cent (176/415). Throat swabs were collected from 82 cases, of which pandemic (H1N1) 2009 virus was detected in 15 (18.3%), influenza type A in (6) 7.4 per cent and influenza type B only in one case. A serosurvey carried out showed haemagglutination inhibition antibodies to pandemic (H1N1) 2009 in 52 per cent (216) subjects in the school and 9 per cent (22) in the community. Interpretation &amp; conclusion: Our findings confirmed an outbreak of pandemic (H1N1) 2009 due to local transmission among students in a residential school at Panchgani, Maharashtra, India

Role of Host Immune Response and Viral Load in the Differential Outcome of Pandemic H1N1 (2009) Influenza Virus Infection in Indian Patients

BACKGROUND: An unusually high number of severe pneumonia cases with considerable mortality is being observed with the pandemic H1N1 2009 virus infections globally. In India, all mild as well as critically ill cases were admitted and treated in the government hospitals during the initial phase of the pandemic. The present study was undertaken during this early phase of the pandemic. METHODOLOGY: The role of viral load and host factors in the pathogenesis were assessed by examining 26 mild (MP), 15 critically ill patients (CIP) and 20 healthy controls from Pune, India. Sequential blood and lung aspirate samples were collected from CIP. Viral load and cytokines/chemokine levels were determined from the plasma and lung aspirates of the patients. TLR levels were determined by staining and FACS analysis. Gene profiling was done for both cells in the lung aspirates and PBMCs using TaqMan Low Density arrays. Antibody titres and isotyping was done using HA protein based ELISAs. PRINCIPAL FINDINGS: 13/15 critically ill patients expired. All plasma samples were negative for the virus irrespective of the patient's category. Sequential lung samples from CIP showed lower viral loads questioning association of viral replication with the severity. Anti-rpH1N1-09-HA-IgG titres were significantly higher in critically ill patients and both categories circulated exclusively IgG1 isotype. Critically ill patients exhibited increase in TLR-3, 4, 7 and decrease in TLR-2 expressions. The disease severity correlated with increased plasma levels of IL1RA, IL2, IL6, CCL3, CCL4 and IL10. Majority of the immune-function genes were down-regulated in the PBMCs and up-regulated in the cells from lung aspirates of critically ill patients. No distinct pattern differentiating fatal and surviving patients was observed when sequential samples were examined for various parameters. CONCLUSIONS: Disease severity was associated with pronounced impairment of host immune response

Comparative evaluation of real-time PCR and conventional RT-PCR during two year surveillance for Influenza and RSV among children with acute respiratory infections in Kolkata reveals distinct seasonality of infection

Acute respiratory tract infections (ARTI) are one of the most common cause of morbidity and mortality in young children all over the world. Influenza and Respiratory Syncytial viruses (RSV) are the predominant etiology during seasonal epidemics and thus rapid and sensitive molecular tests for screening &amp; timely identification of epidemics are required. In this study we report comparison of real time PCR (Q-PCR) with conventional RT-PCR for parallel identification of Influenza A or B (Inf-A or -B) and RSV. A total of 1091 respiratory samples were examined from children with suspected ARTI during January 2007- December 2008. Of these 1091 samples, 275 (25.21%) were positive for either Influenza or RSV by Q-PCR compared to 262 (24%) positives by RT-PCR. Overall Inf-A, -B and RSV were detected in a total of 121 (11.075%), 59 (5.38%) and 95 (8.68%) samples respectively. In spite of overlapping clinical symptoms, RSV and Influenza showed distinct seasonal peaks. Inf-A positively and RSV, negatively correlated with rainfall and temperature. No distinct seasonality was observed in Inf-B infections. This is the first report of a systemic surveillance of respiratory viruses with seasonal correlation and prevalence rate from Eastern India. The two year comparative analysis also confirmed feasibility of using Q-PCR in developing countries, which will not only improve scope for prevention of epidemics but also provide crucial epidemiological data from the tropical regions

A Gel-Based Proteomic Comparison of Human Cerebrospinal Fluid between Inflicted and Non-Inflicted Pediatric Traumatic Brain Injury

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63392/1/neu.2006.0061.lowlink.pdf_v03.pd

Nipah Virus-associated Encephalitis Outbreak, Siliguri, India

Nipah virus, not previously detected in India, caused an outbreak of febrile encephalitis in West Bengal