RESUMEN
Human astroviruses (HAstVs) have now emerged as another common cause of non-bacterial acute gastroenteritis (AGE) in humans worldwide. This study investigated the epidemiology and genetic diversity of human astrovirus strains circulating among infants, younger children (up to 6 years), older children and adolescents (>6-17 years) and adults (18 years and above) hospitalized for diarrhea and their role in AGE in Kolkata, India. A total of 2535 fecal samples were screened for the presence of known enteric viral, bacterial and parasitic etiologies by conventional microbiological assays and molecular methods. The overall incidences of sole or mixed infection of HAstV with known enteric viral, bacterial and parasitic pathogens were detected in 60 cases (2.4%) among all age groups. The clinical symptoms of astrovirus-associated acute watery diarrhea cases were recorded for all sole and mixed infection cases. A high number of sole (n = 13/60 [21.7%]) and mixed infection cases (n = 22/60 [36.7%]) were observed in adults (18 years old or more). Considering all age groups, 18 sole infection cases (n = 18/60 [30%]) and 42 mixed infection cases (n = 42/60 [70%]) with Rotavirus (n = 11/25 [44%]), Vibrio cholerae O1 (n = 6/24 [25%]) Cryptosporidium spp and Giardia lamblia (n = 5/13 [38.4%]) were observed. Further, eleven HAstV samples from infants and children (up to 6 years), children and adolescents (>6-17 years) and adults (18 years and above) were analyzed for their sequences of overlap region between ORF1b (RdRp) and ORF2 (capsid). Among these, ten strains were found to have close genetic relatedness to the Japanese strain HAstV_G1 [AB009985]. Additionally, the IDH2211 Kolkata strain showed a close genetic match with the Thai HAstV_G3 strain [EU363889]. Our study reports show that HAstVs as the sole agent and as mixed infection with other known enteric viral, bacterial, parasitic pathogens are also responsible for AGE among infants, children, adolescents and adults in Kolkata, India.
Asunto(s)
Infecciones por Astroviridae/epidemiología , Astroviridae/aislamiento & purificación , Diarrea/epidemiología , Enfermedad Aguda , Adolescente , Adulto , Astroviridae/clasificación , Astroviridae/genética , Infecciones por Astroviridae/parasitología , Infecciones por Astroviridae/virología , Infecciones por Caliciviridae/epidemiología , Niño , Preescolar , Coinfección/epidemiología , Coinfección/parasitología , Coinfección/virología , Diarrea/parasitología , Diarrea/virología , Heces/virología , Femenino , Gastroenteritis/epidemiología , Gastroenteritis/parasitología , Gastroenteritis/virología , Variación Genética , Genotipo , Hospitalización , Humanos , India/epidemiología , Lactante , Masculino , Datos de Secuencia Molecular , Norovirus/aislamiento & purificación , Enfermedades Parasitarias/epidemiología , Rotavirus/aislamiento & purificación , Infecciones por Rotavirus/epidemiología , Estaciones del AñoRESUMEN
Norovirus (NoV) is a leading cause of non bacterial acute gastroenteritis in human beings. Molecular characterization of NoVs following continuous, stringent surveillance had earlier shown that novel strains representing an intergenogroup as well as GII NoV intergenotype recombinants were in circulation among acute watery diarrhoea cases in Kolkata, India. The present study documents characterization of two recombinant NoV strains (Hu/NoV/ IDH1501/2009/IND and Hu/NoV/IDH1873/2009/IND) along with other interesting GII NoV strains. Similarity plot and phylogenetic analysis confirmed the strain Hu/NoV/IDH1501/2009/IND as a NoV recombinant strain with genes for RNA dependent RNA polymerase (RdRp) GII.1-like and capsid GII.13-like; the strain Hu/NoV/IDH1873/2009/IND was a NoV recombinant strain with its RdRp gene GII.5-like and capsid gene being GII.13-like. Clinical symptoms chiefly associated with the cases that had NoV infection was varying duration of diarrohea and vomiting with some dehydration.
RESUMEN
Picobirnaviruses (PBV) are small, non-enveloped viruses with a bisegmented double-stranded RNA genome. In this study a PBV strain, PBV/Horse/India/BG-Eq-3/2010, was identified in the faeces of a 10 month old weaned female foal with diarrhoea in January 2010 from Kolkata, India. Surprisingly, sequence comparison and phylogenetic analysis of a short stretch of the RNA dependent RNA polymerase gene revealed close genetic relatedness (> 98% nucleotide identity) to a human genogroup I PBV strain (Hu/GPBV1) detected earlier from the same part of India. Our observations together with earlier findings on genetic relatedness between human and animal PBV warrant further studies on zoonotic potential.