Antiviral drug profile of human influenza A & B viruses circulating in India: 2004-2011.

BACKGROUND & OBJECTIVES: Recent influenza antiviral resistance studies in South East Asia, Europe and the United States reveal adamantane and neuraminidase inhibitor (NAIs) resistance. This study was undertaken to evaluate antiviral resistance in influenza viruses isolated from various parts of India, during 2004 to 2011. METHODS: Influenza viruses were analyzed genetically for known resistance markers by M2 and NA gene sequencing. Influenza A/H1N1 (n=206), A/H3N2 (n=371) viruses for amantadine resistance and A/H1N1 (n=206), A/H3N2 (n=272) and type B (n=326) for oseltamivir resistance were sequenced. Pandemic (H1N1) (n=493) isolates were tested for H274Y mutation by real time reverse transcription (rRT)-PCR. Randomly selected resistant and sensitive influenza A/H1N1 and A/H3N2 viruses were confirmed by phenotypic assay. RESULTS: Serine to asparagine (S3IN) mutation was detected in six isolates of 2007-2008. One dual-resistant A/H1N1 was detected for the first time in India with leucine to phenylalanine (L26F) mutation in M2 gene and H274Y mutation in NA gene. A/H3N2 viruses showed an increase in resistance to amantadine from 22.5 per cent in 2005 to 100 per cent in 2008 onwards with S3IN mutation. Fifty of the 61 (82%) A/H1N1 viruses tested in 2008-2009 were oseltamivir resistant with H274Y mutation, while all A/H3N2, pandemic A/H1N1 and type B isolates remained sensitive. Genetic results were also confirmed by phenotypic analysis of randomly selected 50 resistant A/H1N1 and 40 sensitive A/H3N2 isolates. INTERPRETATION & CONCLUSIONS: Emergence of influenza viruses resistant to amantadine and oseltamivir in spite of negligible usage of antivirals emphasizes the need for continuous monitoring of antiviral resistance.

Factors associated with diarrhoea in young children and incidence of symptomatic rotavirus infection in rural West Bengal, India.

Socio-behavioural factors and pathogens associated with childhood diarrhoea are of global public health concern. Our survey in 696 children aged ⩽2 years in rural West Bengal detected rotavirus as sole pathogen in 8% (17/199) of diarrhoeic stool specimens. Other organisms were detected along with rotavirus in 11% of faecal specimens. A third of the children with rotavirus diarrhoea, according to Vesikari score, had severe illness. The top four rotavirus genotypes were G9P[4] (28%), G1P[8] (19%), G2P[4] (14%) and G8P[4] (8%). In the multivariate model, the practice of 'drawing drinking water by dipping a pot in the storage vessel' [adjusted odds ratio (aOR) 2·21, 95% confidence interval (CI) 1·03-4·74, P = 0·041], and 'children aged ⩽6 months with non-exclusive breastfeeding' (aOR 2·07, 95% CI 1·1-3·82, P = 0·024) had twice the odds of having diarrhoea. Incidence of rotavirus diarrhoea was 24/100 child-years in children aged >6-18 months, 19/100 child-years in children aged >18-24 months and 5/100 child-years in those aged ⩽6 months. Results have translational implications for future interventions including vaccine development.

Burden of respiratory tract infections among paediatric in and out-patient units during 2010-11.

INTRODUCTION: Respiratory tract infections due to viral etiology were studied with an objective to identify and compare the pathogens between Hospital Indoor and Outdoor Units. MATERIALS AND METHODS: A hospital-based cross-sectional study was conducted among children below 12 years over a period of one year. The throat and nasal swabs were collected from both the Units and screened for viral infections by real time RT-PCR technique. RESULTS: Out of 880 samples collected, 87% and 13% were from outdoor and indoor Department with total viral positivity rate of 30% and 25% respectively. Influenza B virus (IBV) (n=126, 16%) was more prevalent in Outdoor Unit, whereas respiratory syncytial virus (RSV) (n=18, 16%) among indoor admitted cases. The multinomial logistic regression analysis revealed that both RSV and Influenza viruses were predominant in children of pre-school age groups < 5 years. In the year 2010-11, the prevalence of human metapneumovirus (HMPV) was low. The pandemic influenza A virus (pH1N1/2009) accounted for 4% (n=29) and 0.8% (n=1) cases among Outdoor and Indoor Units respectively. CONCLUSIONS: The Outdoor Department outnumbered the Indoor Unit in terms of patient attendees and the rate of viral infections. An effective vaccination and continuous surveillance program is the need of the hour.

Epidemiology and prospects for prevention of rotavirus disease in India.

CONTEXT: With rotavirus vaccines now available globally, it will be useful to assemble the available evidence on the epidemiology and burden of rotavirus gastroenteritis in India, in order to weigh the urgency of introducing a vaccine to help control rotavirus disease. EVIDENCE ACQUISITION: We reviewed published studies on rotavirus infection and genotype distribution in India, as well as safety and immunogenicity studies of currently available vaccines. PubMed was searched for papers published after 1990, and several authors who are experts in the field recommended papers of known significance. RESULTS: Rotavirus accounts for close to 40% of hospitalizations for diarrhea in India, with more recent studies showing an increased proportion compared with older studies. There is substantial serotype diversity in India, although there is less intra-country variation than previously thought. Two genotypes, G1P[8] and G2P[4], account for roughly 50% of symptomatic infections in non-neonates. Currently licensed vaccines are safe, and although the efficacy appears lower in developing countries, given the extremely high incidence of diarrhea these could still be cost-effective interventions. CONCLUSIONS: The epidemiology and burden of rotavirus diarrhea is fairly well characterized in India. Introducing rotavirus vaccine into the UIP, along with adequate surveillance, should be an important part of efforts to reduce diarrhea mortality, the third leading cause of death among Indian children, and achieve the country's MDG goals.

Full genomic analyses of human rotavirus G4P[4], G4P[6], G9P[19] and G10P[6] strains from North-eastern India: evidence for interspecies transmission and complex reassortment events.

In hospitalized patients with acute gastroenteritis in Manipur, India, four rotavirus strains were found to possess VP7 and/or VP4 genes with porcine or bovine characteristics. Considering the animal-like nature of these strains, the remaining eight gene segments were analysed to decipher their exact origin. Analyses of full genome of these strains exhibited their origin from porcine/bovine rotaviruses. This study suggests single or multiple events of reassortment involving multiple gene segments of more than one host type among the strains and emphasizes the significance of complete genetic characterization of unusual strains in regions with high incidence and mortality rates.

Cell death regulation during influenza A virus infection by matrix (M1) protein: a model of viral control over the cellular survival pathway.

During early infection, viruses activate cellular stress-response proteins such as heat-shock proteins (Hsps) to counteract apoptosis, but later on, they modulate these proteins to stimulate apoptosis for efficient viral dissemination. Hsp70 has been attributed to modulate viral entry, transcription, nuclear translocation and virion formation. It also exerts its anti-apoptotic function by binding to apoptosis protease-activating factor 1 (Apaf-1) and disrupting apoptosome formation. Here, we show that influenza A virus can regulate the anti-apoptotic function of Hsp70 through viral protein M1 (matrix 1). M1 itself did not induce apoptosis, but enhanced the effects of apoptotic inducers. M1-small-interfering RNA inhibits virus-induced apoptosis in cells after either virus infection or overexpression of the M1 protein. M1 binds to Hsp70, which results in reduced interaction between Hsp70 and Apaf-1. In a cell-free system, the M1 protein mediates procaspase-9 activation induced by cytochrome c/deoxyadenosine triphosphate. A study involving deletion mutants confirmed the role of the C-terminus substrate-binding domain (EEVD) of Hsp70 and amino acids 128-165 of M1 for this association. The M1 mutants, which did not co-immunoprecipitate with Hsp70, failed to induce apoptosis. Overall, the study confirms the proapoptotic function of the M1 protein during influenza virus infection.

Full genomic analysis and possible origin of a porcine G12 rotavirus strain RU172.

Human group A rotavirus (GAR) G12 strains are regarded as potentially important pathogens for acute gastroenteritis. On the other hand, to date, the only report of detection of G12 in animals was that of a porcine G12P[7] strain RU172. Strain RU172 formed a separate G12 lineage, distinct from human G12 strains, and by analyses of deduced amino acid sequences, had a VP4, VP6, NSP4-5 of porcine origin. In the present study, we determined the full-length nucleotide sequences of VP1, VP3, and NSP1-3 genes and nearly full-length nucleotide sequence of VP2 gene of RU172. By nucleotide sequence identities and phylogenetic analyses, the VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5 genes of RU172 were assigned to G12-P[7]-I5-R1-C1-M1-A1-N1-T1-E1-H1 genotypes, respectively. Within their respective genotypes, (i) VP1 gene of RU172 exhibited higher genetic relatedness to Wa-like human G12 GARs than porcine strains, (ii) VP2-3 and NSP2 genes clustered separately from the Wa-like human (including G12) and porcine clusters, while (iii) the VP6, NSP1 and NSP3-5 genes clustered with porcine and porcine-like human strains. These observations suggested that (i) the porcine G12 strain might have originated from porcine-human reassortment events, or alternatively, (ii) the Wa-like human and porcine G12 strains might have originated from a common ancestor, and eventually evolved (by genetic drift and shift) with time. Our findings provided important insights into the possible patterns of evolution of the porcine G12 strain.

Molecular characterization of the VP1, VP2, VP4, VP6, NSP1 and NSP2 genes of bovine group B rotaviruses: identification of a novel VP4 genotype.

Studies on bovine group B rotaviruses (GBRs) are limited. To date, only the VP6 gene of a single bovine GBR strain and the VP7 and NSP5 genes of a few bovine GBR strains have been sequenced and analyzed. In the present study, using a single-primer amplification method, we have determined the full-length nucleotide sequences of the VP1, VP2, VP4, VP6, NSP1 and NSP2 genes of three bovine GBR strains from eastern India. In all six of these genes, the bovine GBR strains shared high genetic relatedness among themselves but exhibited high genetic diversity with cognate genes of human, murine and ovine GBRs. Interestingly, as with group A rotaviruses, the bovine GBR VP1, VP2, VP6 and NSP2 genes appeared to be more conserved than the VP4 and NSP1 genes among strains of different species. The present study provides important insights into the genetic makeup and diversity of bovine GBRs, and also identifies a novel GBR VP4 genotype.

Human group A rotavirus P[8] Hun9-like and rare OP354-like strains are circulating among diarrhoeic children in Eastern India.

During 2004-2006, group A rotavirus P[8] strains were the major VP4 genotype (43.2%, n = 317) among diarrhoeic children in Eastern India. Phylogenetic analysis of VP8* amino acid sequences of 16 of these strains with other P[8] strains revealed four distinct lineages. P[8] strains from Eastern India clustered within rare OP354-like and Hun9-like lineages, pointing towards co-prevalence of divergent P[8] strains. Although it is unclear whether the observed genetic diversity might affect to some extent the efficacy of vaccines, the present study emphasized further efforts to address the much lacking information on diversity of P[8] strains across the Indian subcontinent.

Identical rearrangement of NSP3 genes found in three independently isolated virus clones derived from mixed infection and multiple passages of Rotaviruses.

Three rotavirus variants with a rearranged RNA segment derived from the NSP3 gene were isolated in three independent experiments of coinfection and multiple passages of simian rotavirus strain SA11 and single-VP7-gene- or NSP1-gene-substitution reassortants having genetic background of SA11. Sequence analysis indicated that the three rearranged NSP3 genes had almost identical sequences and genomic structures organized by partial duplication of the open reading frame in a head-to-tail orientation following the termination codon. The junction site of the original NSP3 gene (first copy) and the duplicated portion (second copy) was identical among the three rearranged genes, while a direct repeat, i.e., a homologous sequence between the first copy and second template for duplication, typically located at the junction site, was not detected. However, short similar sequences were present at the end of the first copy and beginning of the second copy. These findings suggest that rearrangement of the NSP3 gene may occur at a certain preferential site which is related to sequence similarity between 3'-untranslated region and a region near the 5'-end of ORF.

Downregulation of Bcl-2, FLIP or IAPs (XIAP and survivin) by siRNAs sensitizes resistant melanoma cells to Apo2L/TRAIL-induced apoptosis.

Melanoma cells are relatively resistant to Apo2L/TRAIL (TNF-related apoptosis-inducing ligand). We postulated that resistance might result from higher expression of inhibitors of apoptosis including Bcl-2, FLIP (FLICE-like inhibitory protein) or IAPs such as XIAP (X-linked inhibitor of apoptosis) or survivin. Compared to scrambled or mismatch controls, targeting individual inhibitors with siRNA (si-Bcl-2, si-XIAP, si-FLIP or si-Surv), followed by Apo2L/TRAIL resulted in marked increase in apoptosis in melanoma cells. Compared to Bcl-2 or FLIP, siRNAs against XIAP and survivin were most potent in sensitizing melanoma cells. A similar substantial increase in apoptosis was seen in renal carcinoma cells (SKRC-45, Caki-2), following the inhibition of either XIAP or survivin by siRNAs. Apo2L/TRAIL treatment in IAP-targeted cells resulted in cleavage of Bid, activation of caspase-9 and cleavage of PARP (poly ADP-ribose polymerase). Thus, Apo2L/TRAIL resistance can be overcome by interfering with expression of inhibitors of apoptosis regulating both extrinsic (death receptor) or intrinsic (mitochondrial) pathways of apoptosis in melanoma cells.

Apoptosis and interferons: role of interferon-stimulated genes as mediators of apoptosis.

IFNs are a family of cytokines with pleiotropic biological effects mediated by scores of responsive genes. IFNs were the first human proteins to be effective in cancer therapy and were among the first recombinant DNA products to be used clinically. Both quality and quantity of life has been improved in response to IFNs in various malignancies. Despite its beneficial effects, unraveling the mechanisms of the anti-tumor effects of IFN has proven to be a complex task. IFNs may mediate anti-tumor effects either indirectly by modulating immunomodulatory and anti-angiogenic responses or by directly affecting proliferation or cellular differentiation of tumor cells. Both direct or indirect effects of IFNs result from induction of a subset of genes, called IFN stimulated genes (ISGs). In addition to the ISGs implicated in anti-viral, anti-angiogenic, immunomodulatory and cell cycle inhibitory effects, oligonucleotide microarray studies have identified ISGs with apoptotic functions. These include TNF-alpha related apoptosis inducing ligand (TRAIL/Apo2L), Fas/FasL, XIAP associated factor-1 (XAF-1), caspase-4, caspase-8, dsRNA activated protein kinase (PKR), 2'5'A oligoadenylate synthetase (OAS), death activating protein kinases (DAP kinase), phospholipid scramblase, galectin 9, IFN regulatory factors (IRFs), promyelocytic leukemia gene (PML) and regulators of IFN induced death (RIDs). In vitro IFN-alpha, IFN-beta and IFN-gamma induced apoptosis in multiple cell lines of varied histologies. This review will emphasize possible mechanisms and the role of ISGs involved in mediating apoptotic function of IFNs.

Preferential induction of apoptosis by interferon (IFN)-beta compared with IFN-alpha2: correlation with TRAIL/Apo2L induction in melanoma cell lines.

On the basis of in vitro inhibition of tumor cell growth, IFNs have been generally considered to be antiproliferative proteins. To probe further the potential mechanisms of the antitumor effects of IFNs, we have assessed apoptosis in response to IFN-alpha2 and IFN-beta in cell lines of varied histologies, with a focus on melanomas. Many of the cell lines tested underwent apoptosis in response to IFN-beta, as assessed both by Annexin V and terminal deoxynucleotidyl transferase-mediated nick end labeling staining. In general, IFN-beta had greater growth inhibitory and proapoptotic effects than IFN-alpha2 on all cell lines. The melanoma cell line WM9, sensitive to growth inhibition by IFNs, had a greater degree of apoptosis than A375 melanoma cells, which were largely resistant to antigrowth effects of IFNs. IFN-beta-induced apoptosis was dependent on activation of the caspase cascade with cleavage of caspases 3, 8, and 9 and of the caspase 3 substrate, poly(ADP-ribose) polymerase. Caspase inhibitors benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl keton or benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethyl keton, inhibited IFN-beta-induced apoptosis. Other changes associated with apoptosis, including the movement of cytochrome c from mitochondria to cytoplasm and DNA fragmentation, were also identified in response to IFN-beta. Apo2L ligand [tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)] was one of the early genes induced by IFN-beta in apoptosis-sensitive WM9 cells. Other sensitive melanoma cell lines had a similar IFN-beta-specific induction of TRAIL. Neutralizing antibody to TRAIL inhibited IFN-beta-induced apoptosis in WM9 cells. In resistant A375 cells, IFN-beta did not induce TRAIL/Apo2L expression. Thus, induction of TRAIL by IFNs in some tumor types may initiate the apoptotic cascade. This study offers another mechanism for the antitumor effects of IFNs.