Detection and molecular characterization of noroviruses and sapoviruses in children admitted to hospital with acute gastroenteritis in Vietnam

Noroviruses (NoV) and sapoviruses (SaV) are recognized as important causes of acute gastroenteritis in children worldwide. In this study, the prevalence and genetic variability of NoV and SaV were determined in hospitalized children <5 years of age with acute gastroenteritis in Hanoi, Vietnam. A total of 501 fecal specimens collected between November-2007 and October-2008, that previously had been tested for rotavirus (RV), were tested for NoV and SaV by realtime RT-PCR. Positive samples were genotyped by conventional RT-PCR followed by sequencing. GII NoV was detected in 180 (36%) and SaV in 7 (1.4%) of the samples. NoV was detected year-round ranging from 9.5% in April to 81.5% in September among RV negative samples. NoV GII.4 Minerva (2006b) was the dominant genotype (93%) with a few other genotypes detected including GII.3 (4.4%), GII.13 (1.7%), and GII.2 (0.6%) but no GI strains. Only GI and GII SaV strains were detected in this study. No difference in NoV prevalence between age groups was noted. Frequency of vomiting or fever was similar between children with NoV and RV infection, yet, NoV caused diarrhea with longer duration. In conclusion, NoV is the second most frequent cause of diarrhea in hospitalized children in North Vietnam.     

Porcine noroviruses and sapoviruses on Korean swine farms

Porcine noroviruses (NoVs) and sapoviruses (SaVs), which belong to the family Caliciviridae, have been considered potential zoonotic agents for human infection, and several cases have been reported in Asian countries. In this study, a total of 537 porcine fecal samples collected from 64 swine farms in Korea were tested. Among 537 samples, porcine NoVs were detected by semi-nested RT-PCR in ten samples (1.9%), and porcine SaVs were detected by RT-PCR in 60 samples (11.2%), showing their circulation in Korea. The porcine NoVs were genetically related to strains of genotypes 11 and 18, of genogroup II (GII) of the genus Norovirus. The porcine SaV strains were genetically related to the porcine enteric calicivirus Cowden strain and to the previously identified Korean porcine strains in genogroup III (GIII) of the genus Sapovirus. In no case was co-infection with both NoV and SaV observed in one pig. This is the first report describing porcine NoVs identified in Korea.     

Genetic diversity of noroviruses and sapoviruses in children with acute sporadic gastroenteritis in New Delhi, India

BACKGROUND: Human caliciviruses (HuCVs) cause gastroenteritis throughout the world. Limited information is available on molecular epidemiology of caliciviruses from developing countries including India. OBJECTIVES: Standardization and evaluation of a two-step multiplex RT-PCR assay for HuCVs and characterization of strains. STUDY DESIGN: Two hundred and twenty-six stool samples were collected from children with acute gastroenteritis (AGE) over a one and half year to study the prevalence and diversity of HuCVs in children with AGE in New Delhi, India. A multiplex two-step RT-PCR using 3 sets of external and 4 sets of internal primers from the RdRp gene was standardized for detection of NoVs and SaVs. Molecular characterization of some HuCV strains was done by sequencing followed by phylogenetic analysis. RESULTS: Fifty-nine HuCVs strains were detected in 54 (24%) of the samples; 5 samples had mixed infections. Of these 59 HuCVs, 36 (61%) were norovirus (34 were GGII; 2 were GGI) and 23 (39%) were sapovirus (22 were GGI; 1 was GGII). Phylogenetic analysis of partial RdRp gene of 12 HuCV strains identified three genotypes (GGI/4, GGII/3 and a newly identified GIIb/Hilversum cluster) in NoVs and one genotype (GGI/1) in SaVs. CONCLUSION: This is one of the few reports from India on detection and characterization of HuCVs by multiplex RT-PCR assay. This assay can be a useful tool for epidemiological studies of HuCV infections.     

Genetic diversity of noroviruses and sapoviruses in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand

Human caliciviruses, including norovirus (NoV) and sapovirus (SaV), are recognized as common pathogens that cause acute viral gastroenteritis in children and adults throughout the world. To gain an overview of molecular epidemiology of human caliciviruses in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand, from 2002 to 2004, NoV and SaV were detected and characterized molecularly for identification of their genotypes. From a total of 248 fecal specimens collected, 35 (14.1%) were positive for NoV GII genogroup. Among the 35 NoV GII, GII/4 was the most predominant genotype (22 strains), followed by GII/3 (7 strains), GII/1 (2 strains), GII/7 (2 strains), GII/2 (1 strain), and GII/16 (1 strain). In addition, only three specimens (1.2%) were positive for SaV, each of which was classified into two different genogroups. One isolate was clustered with GIV genogroup, while the other two belonged to two distinct genotypes of the SaV GI cluster, GI/1 and GI/2 genotypes. This study demonstrated that human caliciviruses are important enteric viruses that caused acute gastroenteritis in the hospitalized children in Chiang Mai, Thailand from 2002 to 2004. Moreover, a great genetic diversities of NoV and SaV were observed.     

Prevalence and molecular epidemiology of noroviruses detected in outbreak and sporadic cases of acute gastroenteritis in Bulgaria

Noroviruses constitute a genetically diverse group of viruses in the Caliciviridae family, and are recognized as an important cause of acute non‐bacterial gastroenteritis worldwide. To date there are no data on the incidence of noroviruses as a cause of gastroenteritis in Bulgaria. Fecal samples from an outbreak, and sporadic cases of diarrhea that occurred between December 2006 and April 2007 were tested for the presence of noroviruses. From a total of 474 stools (341 from sporadic cases and 133 cases from a single outbreak) examined, 72 samples (37 from sporadic cases and 35 from the outbreak) were positive using a norovirus‐specific enzyme immunoassay. Fifty‐nine specimens were confirmed and genotyped by RT‐PCR and sequencing of regions of the RNA‐dependent RNA polymerase and/or capsid. Sequence and phylogenetic analyses of 29 norovirus strains revealed a great diversity of norovirus genotypes among the sporadic cases including: GGII.3, GGII.4/2006a, GGII.4/2006b, GGII.20, and GGII.Karachi. A single norovirus genotype (GGII.4/2006b) was identified as the causative agent of the outbreak. This first investigation on the prevalence and molecular epidemiology of noroviruses demonstrates the significant role of these viruses as etiologic agents in acute gastroenteritis in Bulgaria. J. Med. Virol. 80:2161–2168, 2008. © 2008 Wiley‐Liss, Inc.     

Detection and characterization of sapoviruses in outbreaks of gastroenteritis in southwest Germany

BACKGROUND: Sapovirus (SV) has been reported from many countries as one of the major causes of gastroenteritis in infants, but its importance for a broader age range is not well appreciated. While previous studies in our regional laboratory and other parts of Germany have identified Norovirus (NV) as a major cause of gastroenteritis in Germany, the prevalence of SV has not been recorded. OBJECTIVES: To investigate the prevalence of SV in outbreaks of gastroenteritis in Baden-Württemberg, Germany. STUDY DESIGN: Stool specimens from 34 outbreaks of gastroenteritis collected in Baden-Württemberg, Germany in 2002 and 2003, which tested negative for other enteric pathogens were tested for SV by RT-PCR. Positive samples were sequenced and typed using phylogenetic analysis. RESULTS: SV was identified in two of 157 (1.3%) specimens. These two viruses belonged to different genotypes of SV and had a nucleotide similarity of only 57%. CONCLUSIONS: SV circulates within the study area, but is not an important cause of gastroenteritis in the area.     

Molecular characterization of three novel murine noroviruses

Murine noroviruses (MNV) comprise a group of newly recognized pathogens infecting laboratory mice. The first reported murine norovirus, murine norovirus 1 (MNV-1), produces a transient infection with a short duration of fecal shedding after infection of immunocompetent laboratory mice. Our laboratory subsequently isolated three novel murine noroviruses, murine norovirus 2 (MNV-2), murine norovirus 3 (MNV-3), and murine norovirus 4 (MNV-4), that have markedly different pathogenicity from MNV-1 by producing persistent infections and prolonged fecal shedding in infected immunocompetent mice. In this study, the nucleotide sequences and the predicted amino acid sequences of the three novel murine noroviruses were determined and compared to each other, MNV-1, and other previously described human and animal noroviruses. The three novel murine norovirus strains were shown to be related to each other and MNV-1 by sequence and phylogenetic analysis even though MNV-2, MNV-3 and MNV-4 all display markedly different biologic behavior from that of MNV-1. The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession numbers DQ223041, DQ223042, and DQ223043.     

The possible molecular evolution of sapoviruses by inter- and intra-genogroup recombination

Sapporo virus belongs to the genus Sapovirus (family Caliciviridae) and has a non-segmented single-stranded, positive-sense RNA genome. This virus causes acute gastroenteritis in human, porcine and mink hosts. In this study, the complete genome of a Brazilian sapovirus isolate from a child with acute gastroenteritis was determined. A phylogenetic tree was constructed to analyze the genotype of this sapovirus (Sapo_BR-DF01), and possible intra- and inter-genogroups recombination events were evaluated in silico using the RDP3 program. Two inter-genogroup and two intra-genogroup recombination events were newly recognized in this study.     

Prevalence survey and first molecular characterization of Echinococcus granulosus in France

Human cystic echinococcosis (hydatid disease) caused by the Echinococcus granulosus tapeworm continues to be a substantial cause of morbidity and mortality in many parts of the world. France is still considered as endemic area, but the current infestation by E. granulosus of intermediate hosts in France remains currently unknown due to the absence of official data reporting for the last 20 years. A 1-year prevalence survey was conducted in the 24 slaughterhouses of ten departments of the South of France. We demonstrate that the E. granulosus parasite is still currently present at low prevalence at slaughterhouses in the study area (4 cases for 100,000 sheep and 3 cases for 100,000 cattle). In addition, we assess the presence of genotype G1 in infected animals and identify for the first time in France genotypes G2 and G3 of E. granulosus sensu stricto.     

Molecular detection and characterization of noroviruses from children in Botswana

Stool specimens were collected from 100 children in Botswana. RT‐PCR analysis detected noroviruses (NoVs) in 24% of samples tested. Genogroup I and genogroup II strains were identified. There was no association between NoV detection and age or gender. This study is the first indication that NoVs circulate widely in Botswana. J. Med. Virol. 82:321–324, 2010. © 2009 Wiley‐Liss, Inc.