Chi-Neu Tsai

Emerging Norovirus GII.17 in Taiwan

TO THE EDITOR—Human noroviruses (NoVs) are one of the most common causative agents of acute gastroenteritis (AGE) worldwide. Among them, genotype 4 of NoV genogroup II (GII.4) has been the leading cause of NoV-associated AGE [1]. In Taiwan, NoV GII.4 has caused several outbreaks of AGE in either healthcare facilities or community since 2004 [2, 3]. In contrast, NoV GII.17 is considered an uncommon genotype for human infection. This genotypewas first reported from Africa and South America and recently was identified as an outbreak strain in Japan and China [4–6]. Here we report 2 cases of NoV GII.17 infection detected in Taiwan and compared their genome sequences with those collected from other regions of the world. This is the first report of GII.17 in Taiwan.

Acute gastroenteritis caused by multiple enteric pathogens in children.

Of 303 children hospitalized with acute non-bloody, non-mucoid diarrhoea, 69 (22.8%) had polymicrobial infection, including 52 (17.2%) multiple viral infection and 17 (5.6%) viral and bacterial co-infection. Rotavirus had the most important role in both categories; thus the control of rotavirus infection is crucial for maintaining childrens health in Taiwan.

Clinical relevance and genotypes of circulating noroviruses in northern Taiwan, 2006-2011.

The incidence of noroviral gastroenteritis has increased dramatically in recent years, and norovirus (NoV) genogroup II.4 (GII.4) is associated with outbreaks worldwide. The NoV genotypes and their clinical relevance in children hospitalized with acute gastroenteritis between 2006 and 2011 in northern Taiwan were evaluated in this study. NoV sequences were amplified from 47 clinical specimens and phylogenetic analysis was performed. Based on noroviral capsid protein (VP1) and RNA dependent RNA polymerase (RdRp) phylogeny, circulating NoV could be divided into GII.2, GII.3, GII.12, and GII.4 and GII.16, GII.12, GII.g, and GII.4; respectively. The GII.4 subtype was predominant and could be divided further into the 2004 (Hunter), 2006b, and 2010 (New Orleans) subtypes. Regarding clinical manifestations, convulsive disorder occurred only in cases caused by NoV GII.4 2006b. Patients affected by NoV GII.4 2006b presented with a higher frequency of diarrhea (Pu2009=u20090.0204), longer duration of diarrhea (Pu2009=u20090.0215), more frequent hypoglycemia (Pu2009=u20090.038), and electrolyte imbalance (Pu2009=u20090.0487) than acute gastroenteritis caused by NoV GII.4 2010. Structural analysis showed that the amino acid changes in viral VP1 between GII.4 2006b and 2010 subtype were located mainly in the protruding domain 2 (P2 domain). In conclusion, the NoV GII.4 variants 2006b and 2010 were the main causes of acute gastroenteritis in hospitalized children in northern Taiwan during 2006–2011. The clinical presentations and structural changes in VP1 of the two NoV GII.4 variants should be evaluated in the future. J. Med. Virol. 86:335–346, 2014.

Antigenemia and cytokine expression in rotavirus gastroenteritis in children

BACKGROUNDnAntigenemia is commonly found in children with rotavirus infection, although its clinical significance is undetermined. The aim of this study was to evaluate the association of antigenemia with clinical manifestations and cytokine profiles in children infected by rotavirus.nnnMETHODSnIn total, 68 children hospitalized with rotavirus gastroenteritis were enrolled. Serum samples were collected for detection of antigenemia and viremia. Clinical, laboratory and demographic data were analyzed. Proinflammatory, Th1 and Th2 cytokines were evaluated by bead-based flow cytometry.nnnRESULTSnAntigenemia and viremia were found in 45.6% (n = 31) and 5.9% (n = 4) of the 68 rotavirus-infected children, respectively. The mean age of the antigenemia group was significantly greater than that of the non-antigenemia group (43.5 vs. 27.3 months; p = 0.034). The antigenemia group had a significantly shorter length of hospitalization (4.8 vs. 5.8 days; p = 0.0354) in comparison with the non-antigenemia group, and antigenemia was inversely associated with the length of hospitalization (β = 0.31, p = 0.021). A significantly higher tumor necrosis factor (TNF)-β level was found in the patients with antigenemia than those without (236.7 vs. 29.2 pg/mL, p = 0.026). The severity of disease and the rate of extra-intestinal manifestations did not differ between the groups. Viremia was associated with a higher fever (p = 0.012).nnnCONCLUSIONSnAntigenemia was positively correlated with shorter hospital stay in children with rotavirus infection. Enhanced innate and T-cell-mediated immunity evidenced by up-regulation of TNF-β was found in patients with antigenemia.

Severe viral gastroenteritis in children after suboptimal rotavirus immunization in Taiwan.

Background: The study aimed to investigate the molecular epidemiology of severe viral gastroenteritis (AGE) in children in Taiwan after the implementation of the rotavirus vaccine in the private sector. Methods: Fecal samples from hospitalized children with severe AGE from April 2004 to March 2011 were examined by reverse transcription-polymerase chain reaction or polymerase chain reaction to identify enteric viral pathogens. The study period was divided to prevaccine (before September 2006) and postvaccine (after October 2006) periods. The prevalence of enteric viruses between the 2 periods was analyzed. The disease burdens of rotavirus- and norovirus-associated diseases were assessed according to vaccine implementation status and were adjusted for age. Results: A total of 755 stool samples were collected from hospitalized patients with AGE; enteric viruses were identified in 586 patients (77.6%), including 44 with concomitant bacterial infection. Viral enteric infection by rotavirus, norovirus, astrovirus, sapovirus, enteric adenovirus, multiple viruses and bacterial coinfections were found in 216 (28.6%), 128 (17.0%), 24 (3.2%), 6 (0.8%), 69 (9.1 %), 99 (13.1%) and 44 (5.8%) patients, respectively. A significant increase of norovirus infection was found in the postvaccine period (P < 0.001); on the other hand, rotavirus infection in infants has been reduced substainally (P = 0.056) and the annual peak of rotavirus infection has gradually become less prominent, with a significant decline of coinfection of rotavirus with other pathogens. Conclusions: Suboptimal use of rotavirus vaccines in the private sector caused a slow but modest impact on severe rotavirus AGE, whereas norovirus infection became more common.

Intestinal microbiome in children with severe and complicated acute viral gastroenteritis

The aim of the present study was to evaluate the microbiota of children with severe or complicated acute viral gastroenteritis (AGE). To that end, next-generation sequencing (NGS) technology was used to sequence the 16S ribosomal RNA (16S rRNA) gene in 20 hospitalized pediatric patients with severe or complicated AGE and a further 20 otherwise healthy children; the fecal microbiome was then assessed. Comparative metagenomics data were analyzed by a Wilcoxon rank–sum test and hierarchical clustering analysis of bacterial reads. The statistical analyses showed a significantly decreased Shannon diversity index (entropy score) of the intestinal microbiota in patients with severe AGE compared with normal controls (Pu2009=u20090.017) and patients with mild-to-moderate AGE (Pu2009=u20090.011). The intestinal microbiota score of the 5 patients with rotavirus AGE was significantly lower than that of those with norovirus infection (Pu2009=u20090.048). Greater richness in Campylobacteraceae (Pu2009=u20090.0003), Neisseriaceae (Pu2009=u20090.0115), Methylobacteriaceae (Pu2009=u20090.0004), Sphingomonadaceae (Pu2009=u20090.0221), and Enterobacteriaceae (Pu2009=u20090.0451) was found in patients with complicated AGE compared with normal controls. The data suggest a significant reduction in intestinal microbial diversity in patients with severe AGE, particularly those with rotavirus infection.

Emergence in Taiwan of novel norovirus GII.4 variants causing acute gastroenteritis and intestinal haemorrhage in children

Norovirus is the leading cause of viral gastroenteritis globally. Norovirus genotype GII.4 is responsible for the majority of outbreaks, but new variants are continuously emerging. The objective of the study was to delineate the clinical manifestations and complications associated with these new norovirus GII.4 variants in children. We investigated norovirus infections from the community outbreak in October 2011-September 2012 and an earlier outbreak in 2006-2007, in northern Taiwan. Norovirus genotypes and their variants were validated using molecular methods. A norovirus outbreak started in mid-2011 and continued through 2012 in northern Taiwan. Hospitalized children infected by norovirus in 2012 showed a significantly higher incidence of intestinal haemorrhage, as indicated by grossly bloody faeces (P=0.012) and occult blood in faeces (P < 0.001), and also presented with more high fever >39 °C (P < 0.001), fever >38.5 °C (P < 0.001) and fever of any temperature >38 °C (P < 0.001), compared with children hospitalized in 2006-2007. Analysis of 20 near-full-length genome sequences indicated an emergence of GII.4 2012 variants in 2011-2012. Circulating noroviruses can be divided into two clusters: GII.4 2012a, which is identical to the newly reported strain GII.4 Sydney 2012, and GII.4 2012b, which is close to GII.4 2006b, the earlier predominant strain. The emerging new variants of norovirus GII.4 caused a distinct clinical syndrome of acute gastroenteritis with severe fever and a high rate of intestinal haemorrhage in children. The genetic diversity associated with changing clinical manifestations poses major obstacles to norovirus control.

Corrigendum: Intestinal microbiome in children with severe and complicated acute viral gastroenteritis

This corrects the article DOI: 10.1038/srep46130.

Long-term impact of suboptimal rotavirus vaccines on acute gastroenteritis in hospitalized children in Northern Taiwan

BACKGROUND/PURPOSEnRotavirus vaccines were launched in Taiwan since early 2006. Our study was aimed to figure out long-term extended molecular epidemiology in acute gastroenteritis (AGE) in hospitalized young children after rotavirus vaccination in Taiwan.nnnMETHODSnDuring the 10-year period from January 2007 to December 2016, fecal samples from children under 5 years old with AGE hospitalized in Chang Gung Childrens Hospital (CGCH) were examined for enteric pathogens and they were divided into two time intervals: early post-vaccine (Jan. 2007 to Dec. 2011; EPV) and late post-vaccine (Jan. 2012 to Dec. 2016; LPV).nnnRESULTSnIn total, 837 patients with AGE were enrolled with complete study. In the EPV period, 106 (26.7%) rotavirus and 65 (16.4%) norovirus infections were identified as major pathogens. In the LPV period, 79 (17.9%) rotavirus and 98 (22.2%) norovirus infections were diagnosed. Statistical analyses showed a significantly decreased prevalence of rotavirus infection (Pxa0=xa00.002) and a significantly increased prevalence of norovirus (Pxa0=xa00.034) and enteric bacterial infections (Pxa0<xa00.001). A substantial decrease of rotavirus G1 (Pxa0=xa00.079) in the LPV period and norovirus GII.4 prevailed through the decade.nnnCONCLUSIONnIn Taiwan, under a suboptimal rotavirus vaccination policy, there was a marked decrease in the rate of rotavirus AGE of hospitalized young children. Significantly increased norovirus infection has replaced rotavirus as the leading cause. Expansion of rotavirus vaccine coverage, development of a norovirus prevention strategy, and sustained bacterial infection control are important for AGE containment in children in Taiwan.

Complicated norovirus infection and assessment of severity by a modified Vesikari disease score system in hospitalized children

BackgroundNorovirus (NoV) GII.4 is the most common genotype for norovirus gastroenteritis worldwide. New variants or subgenotypes are continuously emerging, thus posing a serious threat to child health.MethodsWe compared retrospectively the clinical manifestations and complications of norovirus gastroenteritis in children from April, 2004 through December, 2012. NoV variants were analyzed to investigate the association of circulating viral strains with the complications. A modified disease severity score system based on Vesikari score system was devised and to evaluate disease severity.ResultsCompared to the outbreak in 2004/2005 winter, significant higher incidence of complications in the later periods are: convulsive disorder (pu2009<u20090.001) in 2006/2007 winter gastrointestinal hemorrhage (pu2009=u20090.047) and severe abdominal pain or irritability (pu2009=u20090.033) in 2008/09/10 winter; gastrointestinal hemorrhage (pu2009=u20090.030), severe abdominal pain or irritability (pu2009=u20090.014), and prominent hyperthermia (fever >39xa0°C, pu2009=u20090.001) in 2011/2012 winter. GII.4 Den_Haag_2006b, GII.4 2010, GII.4 Sydney 2012, and GII.4 2012b were the predominant strains in the outbreaks after 2006. By the modified severity score system, severe norovirus disease occurred in 28.5xa0%, 32xa0%, 33.3xa0%, and 30.2xa0% of the patients in the four periods. A longer duration of hospitalization (pu2009=u20090.02) were found in those with high score irrespective of the year of admission.ConclusionsOur study demonstrated NoV outbreaks in northern Taiwan caused by different GII.4 variants that were associated with specific complications and uncommon clinical presentations. A modified severity score system first proposed in this study was able to identify severe cases with a longer hospital stay in NoV-infected children.