No abstract

Pediatric gastroenteritis is a major cause of childhood morbidity and mortality worldwide, especially in developing countries. It has been increasingly recognised that human caliciviruses (HuCV), comprising noroviruses (NoV), and sapoviruses (SaV), are important in both outbreak and non-outbreak settings. This study aimed to characterise caliciviruses detected in the faeces of hospitalized children and children in the community in India. This study examined 350 faecal samples from children presenting to the hospital with acute gastroenteritis and 673 samples collected from children in the community, 500 from children with diarrhea, and 173 samples from children without diarrhea. Strain characterisation was performed by reverse transcriptionpolymerase chain reaction (RT-PCR) and partial sequencing of the gene encoding the RNAdependent RNA polymerase (RdRp) and/or a region spanning the open reading frames (ORFs) 1 and 2 (ORF1/ORF2) junction. A total of 68 of 350 specimens (19.4%) from hospitalized children were positive, and SaV and NoV accounted for 5.1 and 15.1% of the infections, respectively. Mixed infections of HuCVs with other enteric pathogens were seen in 9.4% of the total children tested. Sixty-eight out of 673 (10.1%) samples collected from children in the community were positive for caliciviruses, and SaV and NoV accounted for 3.4 and 6.6% of the infections. In the community cohort 55/500 (11%) and 13/173 (7.5%) were from symptomatic and asymptomatic children, respectively, and SaVs accounted for 17/500 (3.4%) and NoVs for 38/500 (7.6%) of the symptomatic infections. This is the first report of genotyping of circulating caliciviruses in both hospital and community in India and has increased the evidence for the role of these viruses in pediatric gastroenteritis in India.

We show that the electric field driven surface instability of viscoelastic films has two distinct regimes: (1) The viscoelastic films behaving like a liquid display long wavelengths governed by applied voltage and surface tension, independent of its elastic storage and viscous loss moduli, and (2) the films behaving like a solid require a threshold voltage for the instability whose wavelength always scales as approximately 4xfilm thickness, independent of its surface tension, applied voltage, loss and storage moduli. Wavelength in a narrow transition zone between these regimes depends on the storage modulus.

This study characterized cryptosporidial infections in 48 human immunodeficiency virus-infected individuals in India by multilocus genotyping. Cryptosporidium hominis, C. parvum, C. felis, C. muris, and C. meleagridis were identified. Cpgp40/15 PCR-restriction fragment length polymorphism identified six subgenotypes. Cryptosporidial diarrhea was associated with decreased CD4 counts, below 200 (P ‫؍‬ 0.009), but not high viral loads.

Rotavirus gastroenteritis is the major cause of severe dehydrating diarrhea in children worldwide. This study compares rotavirus diarrhea in 351 children in a community-based cohort and 343 children admitted to a hospital during the same period. Clinical information and fecal specimens were obtained during diarrheal episodes. Fecal samples were screened for VP6 antigen, and the positive samples were G and P typed by reverse transcription-PCR. Rotavirus was detected in 82/1,152 (7.1%) episodes of diarrhea in the community and 94/343 (27.4%) cases in the hospital. The median age of affected children (7.5 versus 10.5 months) and the mean severity of symptoms (Vesikari score, 7.6 ؎ 3.4 versus 11 ؎ 2.5) were lower in the community. A larger proportion of children in the community were breast-fed than were children admitted to the hospital (73% versus 34.8%). In the community, the genotypes identified in symptomatic patients, in order of frequency, were G1 (36.5%), G10 (17.1%), G2 (15.9%), and G9 (7.3%) and mixed infections (7.3%). The most common G-P combinations were G1P

A large proportion of diarrhoeal illnesses in children in developing countries are ascribed to an unknown aetiology because the only available methods, such as microscopy and culture, have low sensitivity. This study was aimed at decreasing the diagnostic gap in diarrhoeal disease by the application of molecular techniques. Faecal samples from 158 children with and 99 children without diarrhoea in a hospital in South India were tested for enteric pathogens using conventional diagnostic methods (culture, microscopy and enzyme immunoassays) and molecular methods (six PCR-based assays). The additional use of molecular techniques increased identification to at least one aetiological agent in 76.5 % of diarrhoeal specimens, compared with 40.5 % using conventional methods. Rotavirus (43.3 %), enteropathogenic Escherichia coli (15.8 %), norovirus (15.8 %) and Cryptosporidium spp. (15.2 %) are currently the most common causes of diarrhoea in hospitalized children in Vellore, in contrast to a study conducted two decades earlier in the same hospital, where bacterial pathogens such as Shigella spp., Campylobacter spp. and enterotoxigenic E. coli were more prevalent. Molecular techniques significantly increased the detection rates of pathogens in children with diarrhoea, but a more intensive study, testing for a wider range of infectious agents and including more information on non-infectious causes of diarrhoea, is required to close the diagnostic gap in diarrhoeal disease.

Rotaviruses are the major etiological agents of diarrhea in children less than 5 years of age. The commonest G types in humans are G1-4 and G9. G12 is a rare human rotavirus (HRV) strain first reported in the Philippines. In this study, 13 G12 strains obtained from a community-based cohort and a hospital-based surveillance system in 2005 were characterized by phylogenetic analysis of partial nucleotide sequences of VP7, VP6, and NSP4 genes. Sequence and phylogenetic analysis of VP7 gene sequences showed that these southern Indian strains had the greatest homology with G12 strains recently reported from eastern India (97-99% identity both at the nucleotide level and deduced amino acid level) and less homology with the prototype G12 strain, L26 (89-90% identity at the nucleotide level and 90-94% at the deduced amino acid level). Phylogenetic analysis of the VP6 and the NSP4 genes revealed that the Vellore G12 strains belonged to VP6 subgroup II and NSP4 genotype B. The P types associated with these strains were P[6] and P [8]. A G12 typespecific primer was designed for inclusion in an established VP7 G-typing multiplex RT PCR, and tested against a panel of known G types and untyped samples and was found to detect G12 strains in the multiplex-PCR. Close homology of the South Indian G12 strains to those from Kolkata suggests that G12 HRV strains are emerging in India. Methods for characterization of rotaviruses in epidemiological studies need to be updated frequently, particularly in developing countries.

The free surface of a soft elastic film becomes unstable and forms an isotropic labyrinth pattern when a rigid flat plate is brought into adhesive contact with the film. These patterns have a characteristic wavelength, lambda approximately 3H, where H is the film thickness. We show that these random structures can be ordered, modulated, and aligned by depositing the elastic film (cross-linked polydimethylsiloxane) on a patterned substrate and by bringing the free surface of the film in increasing adhesive contact with a flat stamp. Interestingly, the influence of the substrate "bleeds" through the film to its free surface. It becomes possible to generate complex two-dimensional ordered structures such as an array of femtoliter beakers even by using a simple one-dimensional stripe patterned substrate when the instability wavelength, lambda approximately 3H, nearly matches the substrate pattern periodicity. The free surface morphology is modulated in situ by merely varying the stamp-surface separation distance. The free surface structures originating from the elastic contact instability can also be made permanent by the UV-ozone induced oxidation and stiffening.