Human astrovirus (HAstV) is a major cause of acute diarrhea among children, resulting in outbreaks of diarrhea and occasionally hospitalization. Improved surveillance and application of sensitive molecular diagnostics have further defined the impact of HAstV infections in children. These studies have shown that HAstV infections are clinically milder (diarrhea, vomiting, fever) than infections with other enteric agents. Among the 8 serotypes of HAstV identified, serotype 1 is the predominant strain worldwide. In addition to serotype 1, the detection rate of HAstV types 2 to 8 has increased by using newly developed assays. HAstV is less common compared with other major gastroenteritis viruses, including norovirus and rotavirus; however, it is a potentially important viral etiological agent with a significant role in acute gastroenteritis. A better understanding of the molecular epidemiology and characteristics of HAstV strains may be valuable to develop specific prevention strategies.
Child ; Diarrhea ; Disease Outbreaks ; Gastroenteritis ; Hospitalization ; Humans ; Mamastrovirus ; Molecular Epidemiology ; Norovirus ; Pathology, Molecular ; Sprains and Strains ; Vomiting

Human astrovirus (HAstV) is a major cause of acute diarrhea among children, resulting in outbreaks of diarrhea and occasionally hospitalization. Improved surveillance and application of sensitive molecular diagnostics have further defined the impact of HAstV infections in children. These studies have shown that HAstV infections are clinically milder (diarrhea, vomiting, fever) than infections with other enteric agents. Among the 8 serotypes of HAstV identified, serotype 1 is the predominant strain worldwide. In addition to serotype 1, the detection rate of HAstV types 2 to 8 has increased by using newly developed assays. HAstV is less common compared with other major gastroenteritis viruses, including norovirus and rotavirus; however, it is a potentially important viral etiological agent with a significant role in acute gastroenteritis. A better understanding of the molecular epidemiology and characteristics of HAstV strains may be valuable to develop specific prevention strategies.
Child ; Diarrhea ; Disease Outbreaks ; Gastroenteritis ; Hospitalization ; Humans ; Mamastrovirus ; Molecular Epidemiology ; Norovirus ; Pathology, Molecular ; Sprains and Strains ; Vomiting

Human astroviruses have been recognized as one of the important causes of viral gastroenteritis in infants and young children. In the present work, we reviewed the progress of astrovirus infections in humans, focusing on the serotypes molecular biological, characteristics of disease, pathogenic mechanism, epidemiology and detection methods, and concluded that there were multiple astroviruses circulating in the world, and several novel astroviruses were discovered in recent years. Human astrovirus 1 was the most prevailing serotype. Which caused intestinal and parenteral infections, and the characteristics of infections were similar to other diarrheal viruses. However, the pathogenic mechanism remained unknown. Only limited data was available about the correlation between the novel astroviruses and diseases, and the laboratory detection methods needed to be established.
Animals ; Astroviridae Infections ; diagnosis ; epidemiology ; pathology ; Cell Line ; Genome, Viral ; genetics ; Humans ; Mamastrovirus ; classification ; genetics ; pathogenicity ; physiology ; Virus Replication

Human astrovirus (HastV) is recognized as one of the leading causes of acute viral diarrhea in infants. The HastV non-structural protein, nsPla, and C-terminal protein, nsPla/4, contain various conserved functional domains,and may play an important role in virus replication, transcription and the virus-host interactions of HastV. This study used an E. coli system to investigate the expression of nsPla and nsPla/4 proteins. Firstly,the nsPla and nsPla/4 genes of HAstV-1 were cloned into the prokaryotic expression vector,PGEX-4T-1, to build the PGEX-4T-1a and PGEX-4T-la/4 fusion protein plasmids. Then, the recombinant plasmids were transformed into Escherichia coli BL21 (DE3) and induced with isopropyl-β-D-thiogalactopyranoside (IPTG). The optimal expression conditions of the two fusion proteins were identified and then analyzed by polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting, respectively. The results showed that the pGEX-4T-la fusion protein was maximally expressed at 30 °C after 12 hours of induction with 1.0 mM IPTG. The pGEX-4T-la/4 fusion protein was maximally expressed at 20 °C after 8 hours of induction with 0.5 mM IPTG. Western blot analysis showed that the two fusion proteins specificity reacted with the anti-nsPla and anti-GST monoclonal antibodies, respectively. This study successfully obtained the HAstV non-structural protein, nsP1a, and its C-terminal protein nsP1a/4 protein using an E. coli system. This novel study lays the foundation for future research into the pathogenic mechanisms of human astrovirus and the functions of its non-structural protein.
Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Gene Expression ; Humans ; Mamastrovirus ; genetics ; metabolism ; Viral Nonstructural Proteins ; genetics ; metabolism

Human astrovirus (HAstV) is one of the leading causes of actue virual diarrhea in infants. HAstV-induced epithdlial cell apoptosis plays an important role in the pathogenesis of HAstV infection. Our previous study indicated that HAstV non-structural protein nsPla C-terminal protein nsPla/4 was the major apoptosis functional protein and probably contained the main apoptosis domains. In order to screen for astrovirus encoded apoptotic protien, nsPla/4 and six turncated proteins, which possessed nsPla/4 protein different function domain ,were cloned into green fluorescent protein (GFP) vector pEG-FP-N3. After 24-72 h transfection, the fusion protein expression in BHK21 cells, was analysis by fluorescence microscope and Western blot. The results indicated seven fusion proteins were observed successfully in BHK21 cell after transfected for 24 h. Western blot analysis showed that the level of fusion protein expressed in BHK21 cells was increased significantly at 72h compared to 48h in transfected cells. The successful expression of deletion mutants of nsPla/4 protein was an important foundation to gain further insights into the function of apoptosis domains of nsPla/4 protein and it would also provide research platform to further confirm the molecule pathogenic mechanism of human astrovirus.
Amino Acid Motifs ; Astroviridae Infections ; virology ; Humans ; Mamastrovirus ; genetics ; metabolism ; Mutation ; Sequence Deletion ; Transfection ; Viral Nonstructural Proteins ; chemistry ; genetics ; metabolism

Adolescent ; Child ; China ; epidemiology ; Disease Outbreaks ; Female ; Humans ; Male ; Mamastrovirus ; drug effects ; genetics ; pathogenicity ; Phylogeny ; Viral Proteins ; genetics

BACKGROUNDThis study was to assess certain epidemiological and clinical characteristics of astrovirus infection in children with diarrhea below 5 years old hospitalized at the Beijing Children's Hospital.

METHODSFrom September 1999 to August 2001, a total of 288 children with diarrhea below 5 years old hospitalized at Beijing Children's Hospital were studied. Fecal specimens collected from each patient were tested for astrovirus by using enzyme immunoassay (EIA) and further serotyped by reverse-transcription polymerase chain reaction (RT-PCR) using serotype-specific primers.

RESULTSAstrovirus antigen was positive in 9.0% of the patients, and the rate of coinfection with rotavirus was 19.2% among the astrovirus positive patients. The patients with astrovirus infection were at the age of 7 days to 17 months, most (92.3%) of them were less than 12 months. Astrovirus infection occurred mainly between October and March of the following year. Main symptoms included watery stool, vomiting, fever, and dehydration. Increased activity of myocardial enzyme was seen in 4 patients. Of the 22 astrovirus positive specimens, 14 were successfully serotyped by RT-PCR and they were all serotype 1.

CONCLUSIONSThe overall incidence of astrovirus infection in young children with diarrhea hospitalized at the Beijing Children's Hospital was 9.0%. The predominant serotype was type 1. Astrovirus may play an important role in viral diarrhea in young children in Beijing, China.

Astroviridae Infections ; diagnosis ; epidemiology ; China ; epidemiology ; Diarrhea ; virology ; Feces ; virology ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Mamastrovirus ; immunology ; isolation & purification ; Serotyping

Astrovirus is frequently associated with diarrhea in children. It can not be readily isolated by cell culture, and an electronmicroscope is usually used for detection of this agent. Recently in 1995 a combined method of reverse transcription-polymerase chain reaction (RT-PCR) was designed for easier detection of astrovirus, which is based on the conserved sequence in 3'-end of genomes of the 7 known serotypes of human astrovirus. As of yet there has not been any report of astrovirus data in Korea using the RT-PCR methods. The purpose of this study was to detect astrovirus incidence, severity of symptoms, seasonal variation and coinfection rate with rotavirus in Korean children inpatients with diarrhea. Fecal specimens from 61 young children hospitalized with gasteroenteritis Korea from Jan. 1996 through Mar. 1997. They were examined for astroviurs infection by RT-PCR method. Results are as follows: 1. Astrovirus was detected at 9.8% (6/61) from fecal specimens of children with severe diarrhea by EIA using monoclonal antibody coated plates. 2. Astorvirus was detected at 29.5% (18/61) from fecal specimens of children with severe diarrhea by RT-PCR. 3. The age of the 18 children affected by astrovirus ranged from 2 monthes to 7 years with mean of 3.0 years. 4. Mean hospital stay of the 1S children was 6.1 days. 5. Five (27.8%) astrovirus RT-PCR positive strains were confirmed in November and in December, respectively out of 18 specimens in total. 6. Astrovirus coinfection with rotavirus type G1 was confirmed in 15/16 specimens (93.8%), and with type G2 was in 1/16 specimens (6.3%).
Cell Culture Techniques ; Child* ; Coinfection ; Conserved Sequence ; Diarrhea ; Feces* ; Genome ; Humans ; Incidence ; Inpatients ; Korea ; Length of Stay ; Mamastrovirus ; Polymerase Chain Reaction* ; Reverse Transcription* ; Rotavirus ; Seasons

PURPOSE: Human astrovirus (HAstV) is known to be an important etiologic agent of acute gastroenteritis in infants worldwide. However, the prevalence of HAstV infection varies according to geographic region and patient age. The purpose of our study was to investigate the incidence of HAstV infection among hospitalized children at a tertiary hospital in Seoul. METHODS: Fecal samples were collected from hospitalized children up to five years of age with acute gastroenteritis. A total of 812 fecal samples were collected from hospitalized children with acute gastroenteritis between February 2004 and January 2005. Fecal specimens were screened for rotavirus, enteric adenovirus and norovirus by enzyme immunoassay (EIA) or reverse transcriptase polymerase chain reaction (RT-PCR). HAstV positive samples were characterized by RT-PCR. RESULTS: Rotavirus was detected in 16.9% (138/812), norovirus in 11.6% (94/812), and adenovirus in 4.0% (33/812) of the study population. HAstV was detected in 4.0% (33/812) samples by RT- PCR. The age distribution of HAstV positive patients was as follows: <12 month old, 82.0% (27/ 33); 1~2 years old, 6.0% (2/33); 2~5 years old, 12.0% (4/33). The seasonal distribution of HAstV positive samples was as follows; April (3), May (5), June (4), August (12), September (4), October (2), November (2), and December (1). The peak rate of HAstV infection was observed during the summer season, 2004. A mixed infection of viral agents was confirmed in 2.7% (22 /812) of the study population, most commonly with rotavirus and norovirus, and with rotavirus and HAstV. Genotype 1 was the predominant type (91%, 20/22) and genotype 8 was detected in two cases. CONCLUSION: The prevalence of HAstV infection was 4.0% in hospitalized children with acute gastroenteritis, and was especially high in infants. HAstV can be considered as an important etiologic agent of gastroenteritis in children.
Adenoviridae ; Age Distribution ; Child ; Child, Hospitalized* ; Coinfection ; Gastroenteritis* ; Genotype ; Humans* ; Immunoenzyme Techniques ; Incidence ; Infant ; Mamastrovirus* ; Molecular Epidemiology* ; Norovirus ; Polymerase Chain Reaction ; Prevalence ; Reverse Transcriptase Polymerase Chain Reaction ; Rotavirus ; Seasons ; Seoul ; Tertiary Care Centers

OBJECTIVETo investigate the etiological characteristics of human rotavirus (HRV), human calicivirus (HuCV), human astrovirus (HAstV) and human enteral adenovirus (HAdV) in Ningxia province during 2011.

METHODSStool specimen was collected from acute diarrhea case of Ningxia during 2011. HRV was detected by ELISA and serotype/genotype identified on those RT-PCR positive specimens. HuCV, HAstV and HAdV were detected by RT-PCR.

RESULTSIn this study, a total of 690 specimens were detected, with the infection rates of HRV, HuCV, HAstV and HAdV as 2.17%, 21.74%, 3.19% and 6.52%, respectively. Co-infections were found in 4.20% of all the samples being tested. Among 15 HRV positive cases, serotypes G1, G3 and P[4] were the most predominant strains.

CONCLUSIONChildren who were under 2 years of age were the majority among patients infected by diarrhea viruses while HuCV was recognized as the main pathogen responsible for the viral diarrhea cases in Ningxia, 2011.

Adenoviruses, Human ; isolation & purification ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Caliciviridae ; isolation & purification ; Child ; Child, Preschool ; China ; epidemiology ; Diarrhea ; virology ; Humans ; Infant ; Infant, Newborn ; Mamastrovirus ; isolation & purification ; Middle Aged ; Rotavirus ; isolation & purification ; Young Adult