A norovirus gastroenteritis outbreak in an Australian child-care center: A household-level analysis

There is a large burden of norovirus disease in child-care centers in Australia and around the world. Despite the ubiquity of norovirus outbreaks in child-care centers, little is known about the extent of this burden within the child-care center and the surrounding household clusters. Therefore, we performed an in-depth analysis of a gastroenteritis outbreak to examine the patterns of transmissions, household attack rates and the basic reproduction number (R0) for Norovirus in a child-care facility. We used data from parental interviews of suspected cases sent home with gastroenteritis at a child-care center between 24th of August and 18th of September 2020. A total of 52 persons in 19 household clusters were symptomatic in this outbreak investigation. Of all transmissions, 23 (46.9%) occurred in the child-care center, the rest occurring in households. We found a household attack rate of 36.5% (95% CI 27.3, 47.1%). Serial intervals were estimated as mean 2.5 ± SD1.45 days. The R0, using time-dependent methods during the growth phase of the outbreak (days 2 to 8) was 2.4 (95% CI 1.50, 3.50). The count of affected persons of a child-care center norovirus outbreak is approximately double the count of the total symptomatic staff and attending children. In the study setting, each symptomatic child-care attendee likely infected one other child-care attendee or staff and just over one household contact on average.

Model estimates of hospitalization discharge rates for norovirus gastroenteritis in Europe, 2004–2015

Background Norovirus is an important cause of acute gastroenteritis globally. However, norovirus is rarely laboratory confirmed or recorded explicitly as a cause of hospitalization. In recent years, there has been an interest in using medical databases and indirect modelling methods to estimate the incidence of norovirus gastroenteritis. The objective of this study was to estimate the incidence of hospitalizations for norovirus gastroenteritis in Europe (2004–2015) using nationwide in-patient discharge records from different European countries. Methods National hospital discharge registers in all 28 European Union countries (at that time) and all 4 European Free Trade Association countries were contacted and invited to participate in the study. Discharges with ICD9/ICD10 codes for acute gastroenteritis (AGE) as first-listed (principal) diagnosis were extracted to assess hospitalization rates for AGE and norovirus gastroenteritis (NGE), overall, by age group, country, month, and seasonal year. The number of cause-unspecified episodes was regressed against pathogen-specific AGE episodes: Rotavirus, Clostridium difficile, Other Bacterial, Other Viral and Parasitic separately. NGE hospital discharges were estimated for each month by calculating the difference between observed cause-unspecified and model-predicted counts, assuming that any remaining seasonality not otherwise captured in the model was due to norovirus, and adding those to the coded NGE episodes to get the total number of norovirus-associated episodes. Results Data were available from 15 countries, representing 68% of the total population in Europe. Only 24.4% of all AGE discharges were coded as cause-specified. We estimated that between 2004 and 2015, the overall rate of NGE hospital discharges in Europe was 3.9 per 10,000 person-years, ranging from 1.2 (Portugal) to 10.7 (Lithuania). Norovirus was predicted to be responsible for 17% of all AGE hospital discharges in Europe in this period. Norovirus affects individuals of all ages, but NGE discharge rates were highest in children < 5 years (24.8 per 10,000 person-years), and adults aged ≥80 years (10.7 per 10,000 person-years). Conclusion We estimated that 1 in 400 hospitalizations in Europe can be attributed to Norovirus. In the absence of routine norovirus testing and recording in hospital settings, modelling methods are useful resources to estimate the incidence of norovirus gastroenteritis.

Clinical significance and intestinal microbiota composition in immunocompromised children with norovirus gastroenteritis

Our study aims to figure out the clinical differences and distribution of intestinal microbiota in immunocompromised children with norovirus (NoV) gastroenteritis. Pediatric patients admitted to Shang-Ho Hospital with diagnosis of acute gastroenteritis with different immune status were enrolled and their medical records were reviewed. NoV gastroenteritis was validated using RT-PCR molecular methods. Viral shedding period was determined by real-time RT-PCR assays. Intestinal microbiota enrichment analysis was carried out by next generation sequencing with Linear Discriminant Analysis (LDA) Effect Size (LEfSe) method. Significantly higher frequency [mean, (IQR), 3.8 (3–5) /day] and longer viral shedding time [mean, IQR, 8.5 (5–13) days] was found in immunocompromised NoV infections than in immunocompetent patients without NoV infections (P = 0.013) and immunocompetent patients with NoV infections (P = 0.030). The fever prevalence was significantly lower in immunocompromised NoV infections. Comparative metagenomics analysis showed a significant difference in richness at the phylum level, the family level, and the genus level in patients under different immune status. We evaluated the clinical significances and microbiota composition in immunocompromised children with norovirus gastroenteritis. This will futher facilitate studies regarding the intestinal microbiota in such patients in determination of bacterial infection control and probiotic supplements strategy.

Benign Convulsions with Mild Rotavirus and Norovirus Gastroenteritis: Nationwide Data from the Health Insurance Review and Assessment Service in South Korea

There have been no large-scale studies on the epidemiology of benign convulsions with mild gastroenteritis (CwG) since the introduction of the rotavirus vaccine in South Korea in 2007. This study aimed to analyze the trends in rotavirus gastroenteritis (RVGE) and rotavirus-associated CwG (RaCwG) after rotavirus vaccination. Further, we aimed to analyze changes in norovirus gastroenteritis (NVGE) and norovirus-associated CwG (NaCwG) using nationwide data from the Korean Health Insurance Review and Assessment Service. Between 2007 and 2019, this study analyzed children aged <6 years who were diagnosed with RVGE, NVGE, RaCwG and NaCwG. The changes in the prevalence of each disease and the ratio of CwG to enteritis were analyzed and the effects of age, sex and season were also analyzed. RVGE, RaCwG, NVGE and NaCwG were diagnosed in 273,898, 4246, 35,593 and 337 patients, respectively. The prevalence of RVGE was on a decreasing trend every year, but the prevalence of NaCwG and NVGE was on an increasing trend. There was a significant annual increase in the ratio of CwG to enteritis in both viruses. In order to control the prevalence of RaCwG, measures other than the rotavirus vaccine are required and measures to prevent norovirus are necessary.

Norovirus Causes Pediatric Encephalopathy and Status Epilepticus: A Case Report and Review of the Literature

Norovirus is a common cause of acute gastroenteritis outbreaks worldwide. The disease can present with varying degrees of neurologic impairment from benign convulsions to rare cases of severe encephalopathy. We describe a case report of a North American infant who presented with norovirus gastroenteritis, status epilepticus, severe encephalopathy, and abnormal but reversible diffusion restriction changes on magnetic resonance imaging of brain.

FECAL MICROBIOME OF CHILDREN WITH NOROVIRUS GASTROENTERITIS

ABSTRACTThe human fecal microbiome is composed of endogenous bacteria, eukaryotic viruses, bacteriophages and retroviruses. Several pathological conditions, including gastroenteritis, may be characterized by imbalance of gastrointestinal functions, with alteration in the diversity and composition of the fecal microbiota. Were analyzed twenty-seven fecal microbiome in children hospitalized with gastroenteritis (norovirus positive) from northern region of Brazil. After sequencing, was verified the presence of the domains Bacteria (95%) and Eukaryota (3.1%), the viruses represented 1.9%. Among the pathogenic viruses were found in addition to noroviruses the picornaviruses, enterovirus and parechovirus. The bacteriophages detected were of Caudovirales order, families Siphoviridae, Podoviridae and Myoviridae. In 22.2% (6/27) of the samples was observed co-infection between norovirus, enterovirus B and echovirus. As for the others components of the microbiome, we can highlight the presence of the taxonomic groups: Terrabacteria (50.2%), composed mainly of Actinobacteria and Firmicutes; Proteobacteria (34.5%) represented by the Enterobacteriaceae family; and FCB group (22%) whose most abundant microorganisms were those of the phylum Bacterioidetes. We performed a metagenomic approach to analyze the fecal microbiota of children with viral gastroenteritis, it was observed that the bacterias (Enterobacteriaceae) deserve attention in a possible association with noroviruses, as they were found in large quantities in infections. In addition, other enteric viruses were observed, such as enteroviruses.

#11: Metronidazole for the Treatment of Norovirus in Transplant Recipients

Background Norovirus is a common cause of gastroenteritis in both immunocompetent and immunocompromised hosts. In transplant recipients, it can lead to prolonged shedding and chronic diarrhea. Treatment with nitazoxanide, oral immunoglobulin, or mammalian target of rapamycin (mTOR) inhibitors have shown varying degrees of benefit in small studies. The commensal gastrointestinal bacterial flora may influence the pathogenesis of norovirus infection. Metronidazole is often used to modulate gastrointestinal flora, and improvement of an HIV patient with suspected Giardia infection subsequently identified to have norovirus suggested a possible use of this drug for other immune-suppressed patients with norovirus infection. Methods Solid-organ or stem cell transplant recipients testing positive for norovirus in stool from July 2014 to March 2019 were identified from the medical record. Patient characteristics, laboratory data, and medications were systematically reviewed to identify factors associated with clinical improvement. Results Thirty-eight patients met inclusion criteria. Almost 75% of the patients were male. Almost 80% of the patients were solid-organ transplant recipients: 40% heart, 24% kidney, and 15% liver. There were 85 positive norovirus tests among the 38 patients. Of these, 14 involved coinfections with another potential pathogen: 11 with adenovirus, 2 with Clostridioides difficile, and 1 with cytomegalovirus. In 25 of the 85 positive norovirus tests, nitazoxanide was given. Clinical improvement was documented in 15 of these episodes (60%), while no improvement was observed in 10 (40%). Eight positive tests were treated with metronidazole alone, with documented improvement observed during 6 (75%) courses. In 9 additional episodes, metronidazole was given within a week of the test result and 2 of these had improvement. When other antibiotics were used concurrently with metronidazole, 78% of episodes (7/9) did not lead to clinical response. Changes in immunosuppression were used for the treatment of 6 episodes, leading to clinical improvement in 5. Conclusion Metronidazole treatment was associated with clinical improvement of norovirus gastroenteritis in transplant recipients at rates similar to those seen with nitazoxanide therapy. Reduction in immunosuppression also led to clinical improvement but in situations where that cannot be done safely, metronidazole may be an alternative to nitazoxanide. In this cohort, metronidazole was only used as a therapy after nitazoxanide, suggesting that a trial of metronidazole as rescue therapy in comparison to a repeat course of nitazoxanide after the initial failure of nitazoxanide is justified.