Characteristics of molecular epidemiology of human astrovirus in hospitalized and outpatient children with acute diarrhea

Abstract

Objective To compare the molecular epidemic characteristics of human astrovirus (HAstV) between outpatient and hospitalized children with acute diarrhea, and to investigate the relationship between HAstV infection and diarrhea in children. Methods A total of 298 cases were randomly collected from hospitalized children from January 2008 to December 2010 in Children′s Hospital of Fudan University, and 360 specimens were collected from outpatients with acute diarrhea from August 2010 to July 2011. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect rotavirus (RV), human calicivirus (HuCV), HAstV and human adenovirus (HAdV). HAstV genotype was determined by gene sequencing and phylogenetic analysis. Results Epidemiology of HAstV in hospitalized children was as follows: among the included 298 samples, HAstV was detected in 27.2% (81/298) of the patients, compared with 33.9% (42/124), 33.8% (25/74) and 14.0% (14/100), respectively from 2008 to 2010. HAstV diarrhea occurred throughout the year and peaked in January, March, and April. 95.1% (77/81) of the infected children were 0-35 months old. All the episodes of HAstV were mixed with other diarrhea virus infection. Molecular epidemiology of HAstV in outpatient children with diarrhea was as follows: the overall incidence of HAstV was 1.9% among the 360 cases (7/360). The seasonal distribution of HAstV′s gastroenteritis showed a peak in November. All the outpatient children were 0-35 months old. Three cases were single infection with HAstV and the others were coinfection with RV (3 cases) or HAdV (1 case). All of the detected HAstV, either in inpatients or outpatients, belonged to HAstV-1. Conclusions The detection rate of HAstV in hospitalized children is significantly higher than that in outpatients. Most HAstV infections in hospitalized children are ascribed to nosocomial infections. Most episodes of HAstV infection were accompanied with other diarrhea viruses infection. HAstV single infection is seen in outpatient children while the detection rate is very low, implying that HAstV co-infection with other viruses plays a main role in diarrhea in most instances. Key words: Mamastrovirus; Genotype; Virus diarrhea; Children