Molecular epidemiology of human picobirnaviruses among children of a slum community in Kolkata, India.
Picobirnaviruses are a group of unclassified, non-enveloped, small spherical viruses, 35-41 nm in diameter without any apparent surface morphology. They have characteristic bisegmented double stranded RNA genome of two types namely large profile (2.3-2.6 kbp for the larger and 1.5-1.9 kbp for the smaller segment, respectively) or small profile (1.75 and 1.55 kbp for segments 1 and 2, respectively). Human picobirnaviruses (n=12 positives; 2/56 diarrhoeic children and 10/607 non-diarrhoeic children) with large (n=11) or small (n=1) genome pattern were observed in faecal specimens of children from a slum community by silver stained PAGE gels. Faecal specimen from four asymptomatic cases (P597_02_IND, K135_02_IND, A373_03_IND, A356_03_IND) and one diarrhoeic case (K135_03_IND) had genogroup I picobirnaviruses (1-CHN-97 like) showing amplicons within the 201 bp region, with primers PicoB25-PicoB43, targeting the conserved domain of RNA-dependent RNA polymerase (RdRp) gene. It was interesting to note that only the PBV strain P597_02_IND from Kolkata with large genome was closely related to a reported strain (similarity with 2-GA-91 from USA was 87% at the nucleotide level and 90% at the amino acid level). Sequence analysis showed three conserved amino acid domains as well as a highly conserved D-S-D motif, characteristic of RNA-dependent RNA polymerase gene of bisegmented, double stranded RNA viruses. Sequence data of the picobirnavirus A356_03_IND indicated strong heterogeneity with all other picobirnavirus strains sequenced till date. After nearly a decade a genogroup II picobirnavirus strain (R227_03_IND) was isolated from a diarrhoea case in the community, with small genome profile and amplified with specific primers PicoB23-PicoB24; but the sequence data showed that it was divergent from the hitherto reported prototype strain 4-GA-91 of genogroup II human picobirnaviruses.
Bhattacharya
Rittwika
R
Division of Virology, National Institute of Cholera & Enteric Diseases, P33 CIT Road, Scheme XM, Beliaghata, Kolkata 700010, India.
Sahoo
Ganesh C
GC
Nayak
Mukti K
MK
Saha
Dhira Rani
DR
Sur
D
D
Naik
T N
TN
Bhattacharya
S K
SK
Krishnan
Triveni
T
D000595:Amino Acid Sequence; D002675:Child, Preschool; D003967:Diarrhea / Q000821:virology; D005243:Feces / Q000821:virology; D016679:Genome, Viral; D006801:Humans; D007194:India / Q000453:epidemiology; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D018708:Picobirnavirus / Q000235:genetics* / Q000302:isolation & purification*; D011204:Poverty Areas; D012327:RNA Virus Infections / Q000453:epidemiology* / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
D014764:Viral Proteins