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

Worldwide prevalence and genotype distribution of human astrovirus in gastroenteritis patients: A systematic review and meta-analysis

AIM

Human astrovirus (HAstV) is an important causative agent of gastroenteritis in humans, which mainly infects young children and the elderly. The goal of this study was to conduct a meta-analytic review of the prevalence of HAstV amongst patients with gastroenteritis, and to shed light on the connection between HAstV infection and gastroenteritis.

METHODS

Systematic literature searches were conducted to identify all potentially relevant studies recorded up to April 8th, 2022. For study weighting, the inverse variance method was employed and the random-effects model was applied to evaluate data. For case-control studies, the pooled odds ratio (OR) and 95% confidence interval (CI) were calculated to establish the relationship between HAstV infection and gastroenteritis.

RESULTS

Among 302423 gastroenteritis patients from 69 different countries, the overall pooled prevalence of HAstV infection was 3.48% (95% CI: 3.11%-3.89%). Case-control approach was used in 39 investigations, and the overall prevalence of HAstV infection among the 11342 healthy controls was 2.01% (95% CI: 1.40%-2.89%). Gastroenteritis and HAstV infection were associated with a pooled OR of 2.16 (95% CI: 1.72-2.71; P < 0.0001; I² = 33.7%). The most commonly found HAstV genotypes in gastroenteritis patients were HAstV1 (62.18%), HAstV7 (33.33%), and HAstV-MLB1 (17.43%).

CONCLUSION

The frequency of HAstV infection was the highest in children under the age of five, and in developing countries. The prevalence rate of HAstV was not influenced by gender. Semi-nested and nested RT-PCR were highly sensitive assays for detecting HAstV infections.

Viral gastroenteritis in rotavirus negative hospitalized children <5 years of age from the independent states of the former Soviet Union

PURPOSE

Rotavirus causes nearly 40% of all hospitalizations for AGE among children <5 years of age in the NIS of the former Soviet Union. The etiologic role of other established gastroenteritis viruses in this age group is unknown.

METHODS

Laboratory-confirmed rotavirus negative fecal specimens (N=495) collected between January and December 2009 from children in 6 NIS (Armenia, Azerbaijan, Belarus, Georgia, Republic of Moldova and Ukraine) were tested for norovirus, sapovirus, enteric adenovirus and astrovirus by real-time RT-PCR. Genotyping was carried out by sequencing and phylogenetic analysis.

RESULTS

Norovirus, enteric adenovirus, sapovirus and astrovirus were detected in 21.8%, 4.0%, 3.2%, and 1.4% of the rotavirus negative specimens, respectively. Mixed infections were identified in 4.1% of the specimens. Phylogenetic analysis showed co-circulation of several different genotypes with GII.4 Den Haag (2006b) norovirus, GI.2 sapovirus, adenovirus type 41, and astrovirus type 1 causing majority of the infections.

CONCLUSION

Norovirus, enteric adenovirus, sapovirus and astrovirus account for a significant proportion (30.5%) of AGE in hospitalized children <5 years of age in 6 NIS.

Analysis of the ORF2 of human astroviruses reveals lineage diversification, recombination and rearrangement and provides the basis for a novel sub-classification system

Canonical human astroviruses (HAstVs) are important enteric pathogens that can be classified genetically and antigenically into eight types. Sequence analysis of small diagnostic regions at either the 5' or 3' end of ORF2 (capsid precursor) is a good proxy for prediction of HAstV types and for distinction of intratypic genetic lineages (subtypes), although lineage diversification/classification has not been investigated systematically. Upon sequence and phylogenetic analysis of the full-length ORF2 of 86 HAstV strains selected from the databases, a detailed classification of HAstVs into lineages was established. Three main lineages could be defined in HAstV-1, four in HAstV-2, two in HAstV-3, three in HAstV-4, three in HAstV-5 and two in HAstV-6. Intratypic (inter-lineages) ORF2 recombinant strains were identified in type 1 (1b/1d) and type 2 (2c/2b) with distinct crossover points. Other potential intratypic recombinant strains were identified in type 3, type 5 and type 6. In addition, a type-1b strain with a large insertion (~600 bp) of heterologous RNA in the N-terminal region and a type-6 strain with a large RNA rearrangement in the hypervariable region were identified. The classification scheme was integrated in a novel nomenclature system suitable for designation of HAstV strains.

Lineage diversification and recombination in type-4 human astroviruses

Human astroviruses (HAstVs) are important enteric pathogens and can be classified genetically and antigenically into eight types. During surveillance of HAstVs in Italy, type-4 HAstVs were detected only sporadically and found to cluster into two distinct genetic groups. Upon sequence analysis of the 3' end of the polymerase gene (ORF1b) and of the full-length ORF2, the 2008 type-4 HAstV strains were characterised as a novel ORF2 genetic lineage, designated as 4c. The 2008 type-4 HAstVs also shared the ORF1b gene with similar HAstV-4c strains detected globally, thus displaying a conserved ORF1b/ORF2 asset. By interrogation of the databases, this novel lineage 4c accounted for 60.8% of the type-4 strains identified worldwide and the vast majority of recent type-4 HAstVs. The 2002 type-4 HAstVs displayed a type-4b ORF2, whereas in the ORF1b they resembled type-1 HAstVs. This inconsistency suggests a possible recombinant origin, with the RNA switch taking place upstream the ORF1b/ORF2 junction region. Also, recombination likely played a role in the diversification of the ORF2 of the three type-4 lineages. Multi-target analysis is required for appropriate characterisation and identification of recombinant HAstVs.

Nationwide surveillance study of human astrovirus infections in an Italian paediatric population

The study investigated the genetic diversity of human astroviruses (HAstVs) detected in children hospitalized with gastroenteritis in Italy in 2008–2009. A total of 1321 faecal samples were collected in Parma (northern Italy), Bari (southern Italy), and Palermo (Sicily) and screened for the presence of HAstVs. RT–PCR amplification of a portion at the 5′-end of ORF2 allowed the detection of HAstVs in 3·95% of the patients. Four different genotypes (HAstV-1, HAstV-2, HAstV-4, HAstV-5) were found to be circulating during the study period, with HAstV-1 being the predominant type. Interestingly, a novel lineage, proposed as HAstV-2d, was found to have emerged in Parma in 2009. Investigating the genetic variability of HAstVs will be important for understanding the epidemiological trends and evolution of these viruses.

The genomic constellation of a novel avian orthoreovirus strain associated with runting-stunting syndrome in broilers

Avian orthoreoviruses (ARVs) are responsible for considerable economic losses in broiler chickens; yet, the genetic characterization of most ARV strains is limited to a few genes, and the full coding region has been determined for only S1133 and 138, two ARV strains associated with tenosynovitis. Recently, in parts of the United States, ARVs with novel neutralization antigen type were isolated from chickens afflicted with runting-stunting syndrome. One such strain, AVS-B, was selected for full genome sequencing and phylogenetic analysis. The complete genome was 23,494 bp in size and included 12 open reading frames. The lengths of the coding regions, as well as those of the 5' and 3' ends, were fairly well conserved between AVS-B and other reference strains. In pairwise comparisons to the S1133 and 138 strains, the AVS-B strain shared a wide range of sequence identities along each genome segment, i.e., a range of 54-55% for the σC coding region of S1 genome segment and 91-93% for the S2 genome segment. Phylogenetic analyses of individual genes of AVS-B did not identify any single common ancestor among more completely characterized ARV strains for which sequence data are available. One exception to this lack of identity was strain 138, which shared 90-93% nt identity with AVS-B along seven of ten genome segments; only M2, M3, and S1 segments of these strains shared lower sequence identities. Collectively, our analyses indicated that multiple reassortment events and strong divergence caused by the accumulation of point mutations could have led to the observed assortment and genetic heterogeneity of the AVS-B genome.

Molecular characterization of rotaviruses in mid-western Turkey, 2006–2007

Vaccines against rotaviruses are now available in numerous countries, including Turkey. As the vaccines may show various efficiencies against different type specificities and routine vaccination in infants might result in selection and immune escape of wild-type rotavirus strains, strain surveillance has been initiated before and during the vaccine introduction. We aimed to provide corresponding information on local strain prevalence in Anatolia, mid-western Turkey during the introduction of rotavirus vaccines. Stool samples positive for group A rotavirus by commercial enzyme immunoassay were subjected to reverse transcription-polymerase chain reaction based genotyping of the outer capsid antigens, VP7 and VP4, determining G and P type specificities respectively. Among 36 fully and 5 partially typeable strains we detected genotype G1, G2, and G9 VP7 specificities and genotype P[4], P[6] and P[8] VP4 specificities in 5 individual and 4 mixed combinations. The most common strain was G2P[4] (n=17), followed by G9P[8] (n=9). Other strains were G1P[8] (n=2), G2P[8] (n=2), G1+2P[8] (n=2), G9P[4] (n=1), G2+9P[8] (n=1), G4+9P[6] (n=1), and G2P[4+8] (n=1). Partially typed strains included 2 G1P[NT] and 3 G2P[NT] strains. Our data may help determine a baseline of the rotavirus genotype prevalence in Turkey and see if changes in the incidence of individual strains will be observed after routine use of vaccine.

Astrovirus detection in sporadic cases of diarrhea among hospitalized and non-hospitalized children in Rio De Janeiro, Brazil, from 1998 to 2004

We analyzed 379 stool samples collected from January 1998 through December 2004, from hospitalized and non-hospitalized children with diarrhea in Rio de Janeiro, Brazil. These samples had prior negative results for other enteric viruses and bacterial pathogens. The specimens were analyzed for HAstV detection by RT-PCR. HAstV genotypes were determined by sequence analysis of the RT-PCR products. Twenty (5.3%) out of 379 samples were positive for astrovirus. Astrovirus was equally common among inpatients and outpatients and among different age groups. Of 20 HAstV-infected children, 13 (65%) were either hospitalized or received medical care in the emergence department, which suggests that they had a more severe illness. Only 7 (35%) of the 20 HAstV-infected children attended walk-in clinics, which suggests that they had mild disease. Other then diarrhea, fever was the most common symptom among the HAstV-positive patients, followed by vomit and bloody diarrhea. HAstV-1 was the predominant strain although genotypes 2 and 4 were also found. There was no obvious difference among HAstV strains detected from inpatients or outpatients or among different age groups. The study documented that astrovirus is an agent of acute diarrhea in children who are inpatients or outpatients in Rio de Janeiro, Brazil although it seems to be less common as a single cause of childhood diarrhea then rotavirus.

First detection of a human astrovirus type 8 in a child with diarrhea in Belém, Brazil: comparison with other strains worldwide and identification of possible three lineages

This study describes the genetic relationships of the first human astrovirus type-8 (HAstV-8) detected in Belém-Brazil, during a public hospital-based study. This strain was compared with other HAstV-8 strains identified elsewhere which have sequences available at GeneBank. The regions ORF1a (primers Mon348/Mon340) and ORF2 (primers Mon269/Mon270) were analyzed by nucleotide sequencing and a high similarity rate was observed among the Belém strain and other HAstV-8 strains. In ORF1a, homology values of 93-100% were detected, and in ORF2 96-99%. Considering the sequence variation (7%) observed in ORF2 region, it was suggested that HAstV-8 strains could be divided in three different lineages.

Molecular epidemiology of astrovirus type 1 in Belém, Brazil, as an agent of infantile gastroenteritis, over a period of 18 years (1982–2000): Identification of two possible new lineages

Human astroviruses (HAstV) are worldwide recognized as important viral enteropathogens during childhood. This study aims to determine the incidence, genetic diversity and intertype variability of HAstV-1 in children less than 5 years of age enrolled in several studies conducted in Belém/Pará, and São Luís/Maranhão, Brazil, from December 1982 to May 2000. Using EIA and RT-PCR, an overall positivity of 6.1% (155/2.534) was achieved, of these, 140 were positive by RT-PCR. The analysis of a 348bp ORF2 fragment revealed that HAstV-1 was the predominant genotype (85/140, 60.7%) throughout the 18 years of study. Phylogenetic analysis was performed for 81 of these strains, and 76 (93.8%) were genetically classified as HAstV-1a. The remainder of strains (n=5) were assigned to possible new lineages, 1e and 1f. Four of these five strains were detected in 1983 and 1984, and the lineage 1a circulated during 10 consecutive years (1990/2000). Genome sequence variation was found among the HAstV-1 strains involving all lineages, but only five nucleotide changes translated into aminoacid changes over this period, suggesting that HAstV-1 was very stable. The data obtained in this study should be useful for further studies at molecular level, including improvement of disease surveillance based on molecular diagnostic tools, and vaccine development.

[Epidemiology of infectious acute diarrhoea in France and Europe]

Acute infectious diarrhoea can be linked to various pathogens among which viruses are responsible for more than a half cases. Rotaviruses and caliciviruses are the most frequently encountered, in close to 60 % of viral gastroenteritis. Rotaviruses account for more than 50 % of severe diseases and caliciviruses, especially norovirus are responsible for less severe sporadic gastroenteritis and water-or food- borne epidemics. Astroviruses and adenoviruses are minority, excepted for immunocompromised patients. Viral or Bacterial and viral co- infections are frequent (up to 15 %). To date, the first rotavirus vaccine assays did not reveal any shift from a viral genus to another, such as calicivirus or adenovirus, according to the fact that epidemiologic features of these viruses are quite different. Progress in viral diagnosis and genotyping enabled to analyse viral diversity and to follow viral recombination events, and emergence of new variants that could propagate among various countries. This dynamic evolution that concerns not only Europe but also developing countries should be carefully surveyed at the era of rotavirus vaccination.

Human astroviruses in raw sewage samples in Hungary

AIMS

Routine procedures for monitoring viruses in water samples have not been drawn up for the water-microbiology screening panel. Enteric viruses, including astroviruses, are able to persist under environmental conditions and may cause public health problems by contaminating natural and drinking water resources. The aim of this study was to detect human astroviruses (HAstVs) from raw wastewater samples.

METHODS AND RESULTS

To obtain data on whether human astroviruses are shed in the environment, 35 raw sewage samples from 22 sewage plants in different regions of Baranya County, Hungary were tested for astrovirus using a polyethylene glycol method for concentration and a guanidinium thiocyanate-silica procedure for extraction of viral RNA. Reverse transcription-polymerase chain reaction (RT-PCR) with HAstV-specific primer pairs was used for amplification and the specificity of amplicons was confirmed by nucleotide sequencing and phylogenetic analysis. Among the 35 raw sewage samples, 15 (43%) contained HAstV and by sequence analysis, 10 genotype HAstV-1 and one genotype HAstV-2 were identified.

CONCLUSIONS

The high detection rate of astroviruses we encountered in this study provide convincing evidence that HAstVs circulate at a relatively high frequency in the Hungarian population. No correlation between the standard indicators of faecal pollution and the presence of HAstVs was found.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our study is the first report on detection of HAstV in sewage in Hungary and suggests that HAstV might be potent indicators of viral pollution in environmental specimens.

Prevalence of human astrovirus genotypes associated with acute gastroenteritis among children in Belém, Brazil

Worldwide human astroviruses (HAstV) have increasingly been recognized as causative agents of viral gastroenteritis, mainly in infants and young children. The aim of this study was to assess the epidemiology and genotype diversity of HAstVs detected in children who participated in a trial in Belém, Brazil with the rhesus human reassortant rotavirus vaccine tetravalent (RRV-TV). From April/1990 to August/1992, 624 diarrheic stool samples were tested by enzyme immunoassay (EIA) for HAstV, with a positive rate of 4.0%. Reverse transcription-polymerase chain reaction (RT-PCR) was done in 129 samples (25 positive and 104 with twice the optical density (OD) value of negative control by EIA) being 33 positive. The overall positivity yielded by both methods was 5.4% (34/624). Genotyping of the 33 positive samples was done by type-specific RT-PCR and confirmed by sequence analysis. Phylogenetic analysis was performed using a 348-bp fragment of the ORF2 region of the capsid gene. HAstV-1 was the most prevalent, accounting for 45.5% of the isolates, followed by HAstV-2 (27.3%), HAstV-3 (12.1%), HAstV-4 (12.1%), and HAstV-6 (3.0%). The monthly distribution showed that HAstV-1 was predominant in the first year of study (May/1990 to May/1991) with highest prevalence in January/1991. HAstV-2 was predominant from July to November/1991 and HAstV-4 from September to October/1990. At 24 months of age, 30.6% of children had been infected by HAstV. The clinical symptoms registered during HAstV associated-diarrhea were usually mild. These data highlight the circulation of the different HAstV genotypes in Belém during the study period.

Genotypes and molecular epidemiology of human astroviruses in hospitalized children with acute gastroenteritis in Rio de Janeiro, Brazil

Human astrovirus (HAstV) is an important pathogen that causes acute gastroenteritis mainly in children up to 5 years old worldwide. A total of 318 fecal samples were collected from January to December of 2004 from children with acute gastroenteritis hospitalized in Rio de Janeiro (RJ), Brazil. The samples were obtained from three public hospitals and were previously investigated for the presence of rotavirus (RV) and enteric adenovirus (AdV). The aim of this study was to determine the prevalence and molecular characterization of HAstV by reverse-transcription polymerase chain reaction (RT-PCR) and partial sequencing of open reading frame 2 (ORF2). HAstV infections were detected in 43 (14%) of the samples, of which 19 (6%) were mixed infections with HAstV and RV. HAstV were identified in all age groups, with 85% of the cases occurring in children younger than 2 years old. HAstV infections were more prevalent from March to May. Diarrhea, vomiting, and fever were the main clinical manifestations observed in these infections. Partial capsid sequencing of 35 HAstV strains characterized 25 (71%) as genotype 1 (HAstV-1), 6 (17%) HAstV-2, 3 (9%) HAstV-8, and 1 (3%) HAstV-4. Based on the genetic variability, three lineages were observed between RJ HAstV-1 strains. This study demonstrated the importance of HAstV infections causing acute infantile gastroenteritis in hospitalized children in RJ, Brazil. Molecular epidemiological surveillance is helpful for designing prevention strategies of HAstV transmission.

First experience with diagnosing astroviral infections in children hospitalized in Pilsen (Czechia)

Between the years 2000-2002 astroviral infection was confirmed in 0.8 % of 2606 children admitted for a diarrheal disease to the University Hospital in Pilsen (Czechia). Astrovirus infections most frequently occurred in the age group between 49-60 months, and 77.3 % of the infections occurred in winter. When the incidence was calculated for these most susceptible age groups, the positive rates were 2.4 % (between 49-60 months) and 1.2 % (between 7-12 months) respectively. On average the hospitalization lasted for 5 d, the diarrhea 3.7 d, vomiting 1.1 d, and 40.9 % of infected children had a raised temperature. In 7 out of 872 stool samples (0.8 %), astrovirus antigen has appeared in the course of the monitored period, i.e. nosocomial astrovirus infection was recorded. In view of the rarity of detecting astroviral infections it is probably not effective to include the diagnosis of these infections in the routine panel when examining the children admitted for gastrointestinal infections. The diagnosis of these infections should, however, be performed within the framework of epidemic incidence and in nosocomial infections.

Outbreaks of viral gastroenteritis: whatʼs new in 2004?

PURPOSE OF REVIEW

Descriptions of outbreaks of viral gastroenteritis have become a prominent feature in scientific journals and other media such as the electronic reporting service 'promed'. A review of outbreak reports was done to further our understanding of the burden of disease, common and rare modes of transmission, complications, and possibilities for control and prevention.

RECENT FINDINGS

Viral gastroenteritis outbreaks occur worldwide. In 2004, besides outbreak reports and surveys, there was considerable attention paid to food and waterborne outbreaks and the difficulties in proving these modes of transmission. Costs of viral gastroenteritis outbreaks are high. Complications and unusual manifestations of viral gastroenteritis, such as convulsions, transplant rejection, and chronic infection, may have been underreported.

SUMMARY

Viral gastroenteritis is a very common illness in health care settings that can cause significant disruption. Clinicians working in these settings should be familiar with the epidemiology and the possible modes of transmission of enteric viruses to be able to translate them into strategies for prevention or intervention. Research is needed to support these strategies.

Comparison of clinical characteristics between astrovirus and rotavirus infections diagnosed in 1997 to 2002 in Hungary

AIM

To determine the severity and clinical characteristics of human astrovirus (HAstV) infections among hospitalized children and compare them with children infected by rotavirus.

METHODS

Retrospective, case-control study of astrovirus-infected and rotavirus-infected children. Astroviruses were detected in stool samples by enzyme immunoassay and/or reverse transcriptase-polymerase chain reaction. All stool samples were tested for rotavirus and bacterial pathogens, and all negative samples were further tested for human astrovirus. Children with astrovirus-positive stool samples and complete clinical data were included in this study.

RESULTS

Astrovirus was detected in 29 (1.8%) children, and 63 rotavirus-infected children were included as controls. Astrovirus-infected children had shorter duration of diarrhea than rotavirus-infected children (median 4 and 6 d, respectively; p<0.05), and 79% of the astrovirus infections were associated with a short duration of vomiting (median 1 and 4 d, respectively; p<0.0001). Rotavirus-infected children had longer hospitalization (p<0.050) than astrovirus-infected children.

CONCLUSION

HAstV-infected children had similar symptoms to those occurring in rotavirus infection. However, astrovirus-infected patients had a significantly shorter duration of diarrhea and vomiting, and they required a shorter hospitalization. On the basis of the clinical data and severity scores, children with rotavirus infection had more severe illness.