Burden of Severe Norovirus Disease in Taiwan, 2003-2013

Norovirus Genogroup II Epidemics and the Potential Effect of Climate Change on Norovirus Transmission in Taiwan

The activity of norovirus varies from season to season, and the effect of climate change on the incidence of norovirus outbreaks is a widely recognized yet poorly understood phenomenon. Investigation of the possible association between climatic factors and the incidence of norovirus is key to a better understanding of the epidemiology of norovirus and early prediction of norovirus outbreaks. In this study, clinical stool samples from acute gastroenteritis outbreaks were collected from January 2015 to June 2019 in Taiwan. Data analysis from our study indicated that more than half of the cases were reported in the winter and spring seasons, including those caused by norovirus of genotypes GII (genogroup II).2, GII.3, GII.6, and GII.17, and 45.1% of the patients who tested positive for norovirus were infected by the GII.4 norovirus in autumn. However, GII.6 norovirus accounted for a higher proportion of the cases reported in summer than any other strain. Temperature is a crucial factor influencing patterns of epidemic outbreaks caused by distinct genotypes of norovirus. The results of this study may help experts predict and issue early public warnings of norovirus transmission and understand the effect of climate change on norovirus outbreaks caused by different genotypes and occurring in different locations.

Prevalence, Distribution, and Genotypes of Adenovirus and Norovirus in the Puzi River and Its Tributaries and the Surrounding Areas in Taiwan

This study investigated the prevalence, distribution, and genotypes of adenoviruses (AdVs) and noroviruses (NoVs) in the Puzi River and surrounding areas in Taiwan. The viruses in the water samples were isolated using the membrane filtration method and the viral nucleic acids were extracted. The RNA of NoVs was reverse-transcribed into complementary DNA using reverse transcriptase-polymerase chain reaction. AdVs and NoVs were detected using nested PCR. Genotyping and phylogenetic analyses were performed to identify the various viral genotypes in the water samples. Human adenovirus (HAdVs) and porcine adenovirus (PAdVs) were the predominant genotypes in the water samples. The prevalence of F species HAdVs serotype 41 (79.2%) and C species PAdVs serotype 5 (18.1%) was higher than that of other serotypes. Among NoVs, genogroup GII was more prevalent than GI. In particular, GII.4 (21.2%) and GII.17 (18.2%) were the predominant genotypes, which was consistent with the clinical findings. The prevalence of both AdVs and NoVs was higher in the winter than spring, summer and autumn seasons. AdVs and NoVs detection results were statistically analyzed by investigating their association with water quality indicators. The results revealed that the presence of AdVs was significantly correlated with the heterotrophic bacterial count, total coliform Escherichia coli, turbidity, salinity, and dissolved oxygen. Meanwhile, the presence of NoVs was only significantly correlated with temperature, pH, and dissolved oxygen. Microbial pollution sources may include urban runoff and discharge of water from livestock farms situated near the river and tributaries within this region of Taiwan. Future studies should include comparisons of the presence of AdVs and NoVs in these known pollution sources and water quality monitoring of these watersheds, as this will allow potential identification of pollution sources. Additionally, remediation strategies must be developed to minimize viral contamination in the river ecosystem.

Burden of Norovirus in the United States, as Estimated Based on Administrative Data: Updates for Medically Attended Illness and Mortality, 2001-2015

BACKGROUND

Up-to-date estimates of the burden of norovirus, a leading cause of acute gastroenteritis (AGE) in the United States, are needed to assess the potential value of norovirus vaccines in development. We aimed to estimate the rates, annual counts, and healthcare charges of norovirus-associated ambulatory clinic encounters, emergency department (ED) visits, hospitalizations, and deaths in the United States.

METHODS

We analyzed administrative data on AGE outcomes from 1 July 2001 through 30 June 2015. Data were sourced from IBM MarketScan Commercial and Medicare Supplemental Databases (ambulatory clinic and ED visits), the Healthcare Utilization Project National Inpatient Sample (hospitalizations), and the National Center for Health Statistics multiple-cause-of-mortality data (deaths). Outcome data (ambulatory clinic and ED visits, hospitalizations, or deaths) were summarized by month, age group, and setting. Healthcare charges were estimated based on insurance claims. Monthly counts of cause-unspecified gastroenteritis-associated outcomes were modeled as functions of cause-specified outcomes, and model residuals were analyzed to estimate norovirus-associated outcomes. Healthcare charges were estimated by applying average charges per cause-unspecified gastroenteritis encounter to the estimated number of norovirus encounters.

RESULTS

We estimate 900 deaths (95% confidence interval [CI], 650-1100), 109 000 hospitalizations (95% CI, 80 000-145 000), 465 000 ED visits (95% CI, 348 000-610 000), and 2.3 million ambulatory clinic encounters (95% CI, 1.7-2.9 million) annually due to norovirus, with an associated $430-$740 million in healthcare charges.

CONCLUSIONS

Norovirus causes a substantial health burden in the United States each year, and an effective vaccine could have important public health impact.

Estimation of Risk of Death Attributable to Acute Gastroenteritis Not Caused by Clostridioides difficile Infection Among Hospitalized Adults in England

Introduction

The role of an infectious agent may be unclear as the primary cause of death. Furthermore, many infections go undiagnosed, particularly if identification does not affect treatment. To circumvent the limitations of individual death attribution, a population-level assessment of the role of infectious acute gastroenteritis (AGE) was performed.

Methods

Using the Clinical Practice Research Datalink and the Office for National Statistics - Mortality Statistics, covering 16 million patients in the UK, we conducted a matched case-control study to estimate the odds of having AGE not due to Clostridioides difficile infection (CDI) diagnosed in the month before death among hospitalized adults in England. To estimate the number of deaths, we first estimated the attributable fraction (AF). The population attributable fraction (PAF) was then derived by multiplying AF with the proportion of AGE hospitalizations among all hospitalizations. Finally, by multiplying the PAF with the number of deaths, the number of deaths attributable to AGE not caused by CDI among hospitalized patients was estimated.

Results

The odds of having AGE not caused by CDI was 4.6 times higher among fatal compared to non-fatal hospitalizations. The overall PAF was 1.7% for AGE not caused by CDI. The overall number of deaths attributable to AGE not caused by CDI among adults in England is estimated to be 5000 annually.

Discussion

Approximately 5000 of the 276,000 deaths that occur annually among hospitalized adults in England can be attributed to AGE not caused by CDI, which is higher than previously estimated.

Rotavirus-related systemic diseases: clinical manifestation, evidence and pathogenesis

Rotaviruses, double-stranded, non-enveloped RNA viruses, are a global health concern, associated with acute gastroenteritis and secretory-driven watery diarrhoea, especially in infants and young children. Conventionally, rotavirus is primarily viewed as a pathogen for intestinal enterocytes. This notion is challenged, however, by data from patients and animal models documenting extra-intestinal clinical manifestations and viral replication following rotavirus infection. In addition to acute gastroenteritis, rotavirus infection has been linked to various neurological disorders, hepatitis and cholestasis, type 1 diabetes, respiratory illness, myocarditis, renal failure and thrombocytopenia. Concomitantly, molecular studies have provided insight into potential mechanisms by which rotavirus can enter and replicate in non-enterocyte cell types and evade host immune responses. Nevertheless, it is fair to say that the extra-intestinal aspect of the rotavirus infectious process is largely being overlooked by biomedical professionals, and there are gaps in the understanding of mechanisms of pathogenesis. Thus with the aim of increasing public and professional awareness we here provide a description of our current understanding of rotavirus-related extra-intestinal clinical manifestations and associated molecular pathogenesis. Further understanding of the processes involved should prove exceedingly useful for future diagnosis, treatment and prevention of rotavirus-associated disease.

Global prevalence and genotype distribution of norovirus infection in children with gastroenteritis: A meta-analysis on 6 years of research from 2015 to 2020

In the post rotavirus vaccine era, norovirus (NoV) plays an increasingly important role in epidemic and sporadic gastroenteritis among children. This study was designed to provide an updated meta-analytic review of the prevalence of NoV among paediatric patients with gastroenteritis and to clarify the relationship between NoV infection and gastroenteritis. Systematic searches of the literature for potentially relevant studies were carried out from 1 January 2015 to 29 May 2020. The inverse variance method was chosen for weighting of the studies, and the random-effects model was used to analyse data. To determine the association between NoV infection and gastroenteritis in children, pooled odds ratio (OR) and its 95% confidence interval (CI) were computed for case-control studies. The pooled prevalence of NoV infection among 12,0531 children with gastroenteritis from 45 countries across the world was 17.7% (95% CI: 16.3%-19.2%). There were 28 studies with a case-control design, and the pooled prevalence of NoV infection among 11,954 control subjects was 6.7% (95% CI: 5.1%-8.8%). The pooled OR of the association of NoV infection and gastroenteritis was 2.7 (95% CI: 2.2-3.4). The most common NoV genotypes were GII.4 (59.3%) and GII.3 (14.9%). The highest frequency of NoV was found in the age group below 1 year. Our findings indicated a substantial burden of gastroenteritis caused by NoV globally, with GII.4 and GII.3 the major genotypes responsible for the majority of NoV-associated gastroenteritis cases among children. Younger age and male sex can be considered risk factors for NoV-associated gastroenteritis among children.

Humoral and Mucosal Immune Responses to Human Norovirus in the Elderly

BACKGROUND

Most information on mucosal and systemic immune response to norovirus infection is derived from human challenge studies, birth cohort studies, or vaccine trials in healthy adults. However, few data are available on immune responses to norovirus in the elderly.

METHODS

To study the mucosal and systemic immune response against norovirus, 43 long-term care facilities were enrolled prospectively in 2010-2014. Baseline saliva samples from 17 facilities, cases and controls up to day 84 from 10 outbreaks, as well as acute and convalescent sera were collected.

RESULTS

Norovirus-specific immunoglobulin A (IgA) levels in baseline saliva samples were low and increased in both symptomatic patients and asymptomatic shedders at day 5 after onset during outbreaks. Receiver operating characteristics analysis correctly assigned prior norovirus infection in 23 (92%) of 25 participants. Cases and asymptomatic shedders showed seroconversion for IgG (80%), IgA (78%), and blockade antibodies (87%). Salivary IgA levels strongly correlated with increased convalescent serum IgA titers and blockade antibodies.

CONCLUSIONS

Salivary IgA levels strongly correlated with serum IgA titers and blockade antibodies and remained elevated 3 months after a norovirus outbreak. A single salivary sample collected on day 14 could be used to identify recent infection in a suspected outbreak or to monitor population salivary IgA.

Clinical characteristics and risk factors for children with norovirus gastroenteritis in Taiwan

BACKGROUND

Norovirus is a common acute gastroenteritis (AGE) pathogen across all age groups worldwide, which is difficult to differentiate from other pathogens. This study aimed to understand the clinical characteristics and risk factors of norovirus gastroenteritis among children in Taiwan.

METHODS

A prospective AGE surveillance study was conducted in children aged ≤5 years who were hospitalized in 10 major hospitals in Taiwan between 2014 and 2017. The non-AGE control group included healthy children who were matched based on age, gender, season, and geographic area.

RESULTS

Overall, 674 norovirus gastroenteritis patients were enrolled. Fever (p < 0.001), mucoid stool (p < 0.001), and bloody stool (p < 0.001) occurred less frequently among norovirus gastroenteritis patients. Norovirus gastroenteritis patients yielded lower CRP values on admission (21.78 ± 36.81 vs. 46.26 ± 58.12 mg/L, p < 0.001) than non-norovirus controls. Norovirus gastroenteritis patients were associated with higher direct contact rates with AGE patients within 1 week (30.5% vs. 0.97%, p < 0.001), lower hand wash rates before meals (21.6% vs. 15.4%, p = 0.001), lower human milk (15.8% vs. 19.8%, p = 0.045) and guava consumption rates (17.8% vs. 24.3%, p = 0.002) than non-AGE participants.

CONCLUSIONS

Body temperature, stool characteristics, and CRP value can help distinguish the norovirus from other pathogens. The major risk factor of norovirus AGE is contact with AGE patient. Higher frequency of hand wash, human milk, and guava intake may be protective against norovirus gastroenteritis.

Disease burden from foodborne illnesses in Taiwan, 2012-2015

BACKGROUND/PURPOSE

Foodborne disease is a global health problem. We aim to provide the first national estimate on disease burden from foodborne illnesses in Taiwan.

METHODS

We adopted the World Health Organization (WHO) Foodborne Disease Burden Epidemiology Reference Group (FERG) methodology framework, and used a hazard-based incidence approach to calculate disability-adjusted life year (DALY) lost to foodborne diseases. Estimated annual incidences and associated medical costs are based on the National Health Insurance research database. We redistributed incidence of unspecified acute gastroenteritis to specific foodborne pathogens, using reported bacteria, virus, parasite survey results in such cases as the reference. The percentage of foodborne illnesses not seeking medical attention is based on data reported from a nationwide survey.

RESULTS

During 2012-2015, 3,895,914 (90% confidence interval [CI]: 3,493,530-4,442,690) foodborne illnesses (1,445,384 sought medical care, with 50 deaths) occurred annually, which caused a total loss of 4974 (90%CI: 4671-5367) DALYs in Taiwan. The annual medical cost was NT$1.3 billion. Young (<5 years) children had the highest incidence. Among the 53% of foodborne illnesses cases with identifiable causal microorganisms, non-typhoid Salmonella, norovirus, and Vibrio parahaemolyticus were leading pathogens (annual foodborne incidence: 185,977, 157,656, and 99,351, respectively). Cases caused by non-typhoid Salmonella peaked in summer, while that caused by norovirus peaked in winter.

CONCLUSION

Foodborne illnesses cause a substantial disease burden in Taiwan. Establishment of active surveillance and investigation mechanisms for the leading foodborne pathogens is warranted.