Analysis of genotypes of human astrovirus isolates from hospitalized children in northeastern Germany

Co-circulation of classic and novel astrovirus strains in patients with acute gastroenteritis in Germany

OBJECTIVES

In order to analyze the molecular epidemiology of human astroviruses (HAstV) in Germany, a retrospective long-term study was performed to characterize circulating human astrovirus in patients with acute gastroenteritis in Germany.

METHODS

A total of 2877 stool samples, collected between January 2010 and December 2015 from sporadic cases and outbreaks of acute gastroenteritis were retrospectively analyzed for astrovirus. A two-step PCR algorithm was developed and used to identify and characterize human astrovirus infections.

RESULTS

Overall, 143 samples were astrovirus-positive (5.0%). Astrovirus infection was most frequently detectable in samples from children of 3-4 years (15%) followed by children of 1-2 years (8.6%), detection rates in adults were lower (1%-3.6%). A high number (71.3%) of co-infections, mainly with noro- or rotaviruses, were identified. Genotyping revealed that at least ten genotypes from all four human MAstV species were circulating in the study population. HAstV-1 was predominant in different age groups. Novel HAstV (MLB and VA genotypes) were also circulating in Germany.

CONCLUSION

Our findings give new insights into the circulation and genetic diversity of human astroviruses in patients with acute gastroenteritis. The novel HAstV-MLB and -VA genotypes could be characterized firstly in Germany while the analysis showed that these viruses have been dispersed in Germany since 2011 as a causative agent of acute gastroenteritis.

Applicability of microarray technique for the detection of noro- and astroviruses

Noroviruses and astroviruses are widespread viral agents causing gastroenteritis. Noroviruses are actually a diverse group of viruses. A new microarray-based detection method is presented for both noro- and astroviruses. This method enables simultaneous identification of genogroups and types of noro- and astroviruses. For pre-amplification, the monoplex- and multiplex-RT-PCR assays were applied to test sensitivity. The 202 specimens were used to determine the specificity, precision, and accuracy of the microarray. Stool samples representing 13 of norovirus GI and GII genotypes were assayed. The microarray detected all but one genotype. In a panel of 74 stool samples, 45 tested positive for norovirus by microarray, against 35 by a conventional PCR-method. In addition, microarray detected some double infections. In a panel of archival samples, astroviruses of genotype 4 frequently emerged in Finland from 1977 to 1997. This study demonstrates that microarray is useful for simultaneous monitoring of several viruses and their subtypes. Microarray provides a convenient tool for the detection of RNA viruses for which frequent changes in the panel of detection primers may be required.

One-year survey of astrovirus infection in children with gastroenteritis in a large hospital in Hungary: Occurrence and genetic analysis of astroviruses

Human astroviruses (HAstV) are the causative agents of viral gastroenteritis mainly in children worldwide. This study investigated the epidemiology and genotype diversity of HAstVs detected in children admitted to hospital with gastroenteritis in Hungary. Stool samples were collected from children with diarrhea at the Municipal "Szent László" Hospital, Budapest, Hungary, between January 2002 and December 2002. Of 2,758 samples, 607 were negative for both rotaviruses and bacterial pathogens and were tested for astroviruses using a reverse transcriptase-polymerase chain reaction (RT-PCR) targeting the open reading frame (ORF2), capsid region. Astrovirus was detected in 10 samples (1.6%) by RT-PCR. Astrovirus infection was more frequent among children 49 to 60 months of age. Genotyping of positive samples was performed by type-specific RT-PCR and confirmed by sequence analysis. Phylogenetic analysis was performed using a 203 nucleotide consensus length of the 3'-end of the capsid gene. Type-specific RT-PCR and sequence analysis detected genotypes 1 (50%), 4 (30%), 3 (10%), and 8 (10%) among the children admitted to hospital. Genotype 1 was the predominant genotype, but genotypes 3, 4, and 8 were also present indicating the importance of emerging genotype 8 infections. Two distinct genotype 4 variants were observed during this study. Sequence analysis confirmed type-specific RT-PCR results in the capsid region. This is the first comprehensive report on the occurrence of HAstV infections in Central/Eastern Europe.

Molecular characterization and sequence analysis of human astroviruses circulating in Hungary

Human astroviruses (HAstVs) are major pathogens in viral gastroenteritis worldwide. Twenty-five HAstV strains were detected from stool specimens of children hospitalized for acute gastroenteritis in Budapest, Hungary, between 1995 and 1999. Sequence analysis was performed at the 3' end of the capsid gene to determine genotypic diversity of HAstVs circulating in Hungary. Five different genotypes of HAstVs were identified: HAstV-1 was predominant, followed by types 5, 8, 3 and 4. Two different subtypes of HAstV-1 were detected, but only one at a time in the community. This is the first report on the genetic diversity of HAstVs in Hungary and Central/Eastern Europe.

Viral agents of acute gastroenteritis in German children: prevalence and molecular diversity

Acute gastroenteritis is a major source of morbidity and mortality among young children in developed and developing countries. Enteropathogenic viruses are regarded as particularly relevant causative agents. Between February 2001 and January 2002, fecal specimens were obtained from German children admitted to hospital with acute gastroenteritis and examined for rotaviruses, Noroviruses, enteric adenoviruses, and astroviruses using (RT-)PCR methods. Of the 59% (129/217) samples positive for > or =1 viral agent, 79% (102/129) carried rotavirus, whereas Norovirus was detected in 35% (45/129), enteric adenovirus in 14% (18/129), and astrovirus in 4% (5/129). Thirty-eight specimens contained at least two enteropathogenic viruses, with the majority of coinfections attributable to rotavirus/Norovirus dual infections. Sequence analysis revealed a cocirculation of G1, G3, G4, and G9 type rotavirus with G1 being the most common and G9 the second most common rotavirus G-type. Emergence of G9 rotaviruses in Germany may have implications for future vaccine development. A variety of Norovirus genotypes, most belonging to GGII, were found. Apart from subgenus F, adenovirus related genetically to subgenera A-C were detected. All astroviruses belonged to genotype 1. This is the first study concerning German children admitted to hospital that assesses the relative importance of these viruses by nested (RT-) PCR methods.