Epidemiology and genetic diversity of human astrovirus infection among hospitalized patients with acute diarrhea in Bangladesh from 2010 to 2012

Abstract

Background: Globally, human astroviruses (HAstVs) have emerged as another common cause of non-bacterial acute gastroenteritis. Limited data exist on the epidemiology and genetic diversity of HAstVs in Bangladesh.

Objective: We describe the epidemiology of HAstV-associated diarrhea among hospitalized patients, including HAstV genotypes, clinical symptoms and co-infecting pathogens.

Study design: Stool samples were collected from an ongoing diarrhea etiology surveillance during 2010-2012. HAstV was detected using RT-PCR and positive samples were subsequently tested for other common viral and bacterial pathogens. Phylogenetic analysis was performed and genotyped HAstV sequences were compared with previously reported Bangladeshi HAstV strains.

Results: Of 826 fecal specimens, HAstV was detected in 26 cases (3.1%) and the majority of these cases (92%) was observed in children under 3 years of age. For 6 out of the 26 cases (23%) no other co-infecting pathogens were observed, whereas for the 20 remaining cases (77%) a variety of other known enteric viral and bacterial pathogens were observed. Based on the overlap region between ORF1b (RdRp) and ORF2 (capsid), five different genotypes (HAstV-1, -2, -3, -5 and -6) were identified circulating during the study period, with HAstV-1 being the predominant type. Genetic analysis revealed that HAstV-1 strains detected in this study were distantly related (<90% similarity of the capsid protein on the nt level) with HAstV-1 strains previously reported from Bangladesh.

Conclusion: Our study provides an epidemiological overview and genetic diversity of HAstVs associated with acute diarrhea in Bangladesh.

Keywords: Bangladesh; DDSS; Diarrhea; Diarrheal Disease Surveillance System; ELISA; Epidemiology; Genetic diversity; HAstV-1; HAstVs; Human astrovirus (HAstV); International Centre for Diarrhoeal Disease Research, Bangladesh; ORF; RNA dependent RNA polymerase; RT-PCR; RdRp; UV; aa; amino acid; enzyme-linked immunosorbent assay; human astroviruses; icddr,b; nt; nucleotide; open reading frame; reverse transcriptase polymerase chain reaction; ultraviolet.