Burden of acute gastroenteritis, norovirus and rotavirus in a managed care population

Characterization of viroplasm-like structures by co-expression of NSP5 and NSP2 across rotavirus species A to J

Rotaviruses (RVs) are classified into nine species, A-D and F-J, with species A being the most studied. In rotavirus of species A (RVA), replication occurs in viroplasms, which are cytosolic globular inclusions composed of main building block proteins NSP5, NSP2, and VP2. The co-expression of NSP5 with either NSP2 or VP2 in uninfected cells leads to the formation of viroplasm-like structures (VLSs). Although morphologically identical to viroplasms, VLSs do not produce viral progeny but serve as excellent tools for studying complex viroplasms. A knowledge gap exists regarding non-RVA viroplasms due to the lack of specific antibodies and suitable cell culture systems. In this study, we explored the ability of NSP5 and NSP2 from non-RVA species to form VLSs. The co-expression of these two proteins led to globular VLSs in RV species A, B, D, F, G, and I, while RVC formed filamentous VLSs. The co-expression of NSP5 and NSP2 of RV species H and J did not result in VLS formation. Interestingly, NSP5 of all RV species self-oligomerizes, with the ordered C-terminal region, termed the tail, being necessary for self-oligomerization of RV species A-C and G-J. Except for NSP5 from RVJ, all NSP5 interacted with their cognate NSP2. We also found that interspecies VLS are formed between closely related RV species B with G and D with F. Additionally, VLS from RVH and RVJ formed when the tail of NSP5 RVH and RVJ was replaced by the tail of NSP5 from RVA and co-expressed with their respective NSP2.

IMPORTANCE

Rotaviruses (RVs) are classified into nine species, A-D and F-J, infecting mammals and birds. Due to the lack of research tools, all cumulative knowledge on RV replication is based on RV species A (RVA). The RV replication compartments are globular cytosolic structures named viroplasms, which have only been identified in RV species A. In this study, we examined the formation of viroplasm-like structures (VLSs) by the co-expression of NSP5 with NSP2 across RV species A to J. Globular VLSs formed for RV species A, B, D, F, G, and I, while RV species C formed filamentous structures. The RV species H and J did not form VLS with their cognates NSP5 and NSP2. Similar to RVA, NSP5 self-oligomerizes in all RV species, which is required for VLS formation. This study provides basic knowledge of the non-RVA replication mechanisms, which could help develop strategies to halt virus infection across RV species.

Economic Burden of Acute Gastroenteritis among Members of Integrated Healthcare Delivery System, United States, 2014-2016

We conducted a large surveillance study among members of an integrated healthcare delivery system in Pacific Northwest of the United States to estimate medical costs attributable to medically attended acute gastroenteritis (MAAGE) on the day care was sought and during 30-day follow-up. We used multivariable regression to compare costs of MAAGE and non-MAAGE cases matched on age, gender, and index time. Differences accounted for confounders, including race, ethnicity, and history of chronic underlying conditions. Analyses included 73,140 MAAGE episodes from adults and 18,617 from children who were Kaiser Permanente Northwest members during 2014-2016. Total costs were higher for MAAGE cases relative to non-MAAGE comparators as were costs on the day care was sought and costs during follow-up. Costs of MAAGE are substantial relative to the cost of usual-care medical services, and much of the burden accrues during short-term follow-up.

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.

Economic Burden and Influencing Factors of Acute Gastroenteritis in China: A Population-Based Face to Face Survey in 2018

Background

Acute gastroenteritis is an important and highly prevalent public health problem worldwide. The purpose of this study was to assess the economic burden of disease and its influencing factors in patients with acute gastroenteritis in Heilongjiang Province, China.

Methods

A multi-stage stratified random sampling method was used in a face-to-face household survey in 2018. Demographic and socioeconomic characteristics, clinical symptoms, suspicious dietary history, and disease treatment information were collected from 19,647 respondents. One-way analysis of variance and multiple stepwise regression analysis were used to investigate the factors associated with the economic burden of acute gastroenteritis. Quantitative risk analysis and sensitivity analysis were performed to estimate the uncertainty and risk factors of the economic burden of acute gastroenteritis.

Results

The total economic burden of patients with acute gastroenteritis was 63,969.22 CNY (Chinese Yuan), of which the direct economic burden accounted for 63.82%; the per capita economic burden was 131.35 CNY per month. Age, region, disease duration, and disease treatment were the main factors significantly associated with the economic burden of acute gastroenteritis (P &lt; 0.05). The average economic burden of patients with acute gastroenteritis was approximately 571.84 CNY/person (95% CI: 227–1,459). Sensitivity analysis showed that the greatest impact was from the indirect economic burden.

Conclusions

Acute gastroenteritis brings a substantial health burden to patients due to its high incidence. The economic burden of self-purchased drugs and the indirect economic burden of patients cannot be ignored. To better estimate the economic burden of acute gastroenteritis in China, further studies on the pathogen-specific economic burden of acute gastroenteritis are required.

The Cutting Edge of Gastroenteritis: Advances in Understanding of Enteric Infection

ABSTRACT

In recent years, multiple advances have been made in the care, diagnosis, and mechanistic understanding of acute gastroenteritis (AGE). In this review, we discuss the current state of the art of diagnosis and management, as well as how changes in practice can improve care and decrease costs. We will discuss present study demonstrating the effect of AGE on the microbiome and how that may be linked to secondary effects or long-term changes. We will explore the use of novel technologies to further our capacity to understand how gastrointestinal infections occur and promulgate. Finally, will discuss advances in our understanding of how gastrointestinal infections capacitate other changes such as post-viral motility or other post viral intestinal dysfunction.

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06421-z.

Norovirus and Other Viral Causes of Medically Attended Acute Gastroenteritis Across the Age Spectrum: Results from the Medically Attended Acute Gastroenteritis Study in the United States

BACKGROUND

Acute gastroenteritis (AGE) causes a substantial burden in the United States, but its etiology frequently remains undetermined. Active surveillance within an integrated healthcare delivery system was used to estimate the prevalence and incidence of medically attended norovirus, rotavirus, sapovirus, and astrovirus.

METHODS

Active surveillance was conducted among all enrolled members of Kaiser Permanente Northwest during July 2014-June 2016. An age-stratified, representative sample of AGE-associated medical encounters were recruited to provide a stool specimen to be tested for norovirus, rotavirus, sapovirus, and astrovirus. Medically attended AGE (MAAGE) encounters for a patient occurring within 30 days were grouped into 1 episode, and all-cause MAAGE incidence was calculated. Pathogen- and healthcare setting-specific incidence estimates were calculated using age-stratified bootstrapping.

RESULTS

The overall incidence of MAAGE was 40.6 episodes per 1000 person-years (PY), with most episodes requiring no more than outpatient care. Norovirus was the most frequently detected pathogen, with an incidence of 5.5 medically attended episodes per 1000 PY. Incidence of norovirus MAAGE was highest among children aged < 5 years (20.4 episodes per 1000 PY), followed by adults aged ≥ 65 years (4.5 episodes per 1000 PY). Other study pathogens showed similar patterns by age, but lower overall incidence (sapovirus: 2.4 per 1000 PY; astrovirus: 1.3 per 1000 PY; rotavirus: 0.5 per 1000 PY).

CONCLUSIONS

Viral enteropathogens, particularly norovirus, are important contributors to MAAGE, especially among children < 5 years of age. The present findings underline the importance of judicious antibiotics use for pediatric AGE and suggest that an effective norovirus vaccine could substantially reduce MAAGE.

Socioeconomic Impact of the Rotavirus Vaccine in Korea: Comparing the Epidemiologic and Economic Characteristics of Rotavirus Gastroenteritis Before and After the Introduction of Vaccines

BACKGROUND

Since the introduction of 2 rotavirus (RV) vaccines in Korea, the vaccination rate has reached over 80% with out-of-pocket spending in the private market. We investigated the socioeconomic impact of RV vaccines in Korea to assess their value and public health contribution.

METHODS

By using National Health Insurance Service claims data, we compared the epidemiologic and economic characteristics of rotavirus gastroenteritis (RVGE) before and after the introduction of RV vaccines. For each year of the study period, the annual prevalence and national costs of RVGE were estimated based on children under 5 years with at least 1 National Health Insurance Service claims record with a diagnosis of RVGE.

RESULTS

Compared with the prevaccination period, the prevalence of RVGE decreased in the postvaccination period by 48.9% from 2097 per 100,000 children in 2006 to 1072 per 100,000 children in 2015, implying an increase in the vaccination rate and the prevention effect of the vaccines. The highest reduction was observed among those 12 to <24 months of age (-73.4%), presumably due to the benefit of full vaccination, while children under 2 months, ineligible for the RV vaccine, showed an increase (41.7%). The number of hospitalized RVGE cases per year decreased by 69.0%. The national economic burden of RVGE decreased by 28.6%.

CONCLUSIONS

The substantial reduction in the socioeconomic burden of RVGE after the introduction of RV vaccines confirms their benefit to society. This study would help health policy makers make empirical decisions on incorporating the vaccination into national immunization programs.

A prospective comparative study of children with gastroenteritis: emergency department compared with symptomatic care at home

Little is known about the epidemiology and severity of gastroenteritis among children treated at home. We sought to compare illness severity and etiology between children brought for emergency department (ED) care to those managed at home (i.e., community). Prospective cohort study of children enrolled between December 2014 and December 2016 in two pediatric EDs in Alberta, Canada along with children treated at home after telephone triage (i.e., community). Primary outcomes were maximal frequency of vomiting and diarrhea in the 24-h pre-enrollment period; secondary outcomes included etiologic pathogens, dehydration severity, future healthcare visits, and treatments provided. A total of 1613 patients (1317 ED, 296 community) were enrolled. Median maximal frequency of vomiting was higher in the ED cohort (5 (3, 10) vs. 5 (2, 8); P < 0.001). Proportion of children with diarrhea and its 24-h median frequency were lower in the ED cohort (61.3 vs. 82.8% and 2 (0, 6) vs. 4 (1, 7); P < 0.001, respectively). In regression analysis, the ED cohort had a higher maximum number of vomiting episodes pre-enrollment (incident rate ratio (IRR) 1.25; 95% CI 1.12, 1.40) while the community cohort had higher maximal 24-h period diarrheal episodes (IRR 1.20; 95% CI 1.01, 1.43). Norovirus was identified more frequently in the community cohort (36.8% vs. 23.6%; P < 0.001). Children treated in the ED have a greater number of vomiting episodes; those treated at home have more diarrheal episodes. Norovirus is more common among children treated symptomatically at home and thus may represent a greater burden of disease than previously thought.

Estimating healthcare costs of acute gastroenteritis and human campylobacteriosis in Switzerland

Rising numbers of campylobacteriosis case notifications in Switzerland resulted in an increased attention to acute gastroenteritis (AG) in general. Patients with a laboratory-confirmed Campylobacter infection perceive their disease as severe and around 15% of these patients are hospitalized. This study aimed at estimating healthcare costs due to AG and campylobacteriosis in Switzerland. We used official health statistics, data from different studies and expert opinion for estimating individual treatment costs for patients with different illness severity and for extrapolating overall costs due to AG and campylobacteriosis. We estimated that total Swiss healthcare costs resulting from these diseases amount to €29-45 million annually. Data suggest that patients with AG consulting a physician without a stool diagnostic test account for €9·0-24·2 million, patients with a negative stool test result for Campylobacter spp. for €12·3 million, patients testing positive for Campylobacter spp. for €1·8 million and hospitalized campylobacteriosis patients for €6·5 million/year. Healthcare costs of campylobacteriosis are high and most likely increasing in Switzerland considering that campylobacteriosis case notifications steadily increased in the past decade. Costs and potential cost savings for the healthcare system should be considered when designing sectorial and cross-sectorial interventions to reduce the burden of human campylobacteriosis in Switzerland.

Modelling Estimates of Norovirus Disease in Patients with Chronic Medical Conditions

BACKGROUND

The burden of disease due to norovirus infection has been well described in the general United States population, but studies of norovirus occurrence among persons with chronic medical conditions have been limited mostly to the immunocompromised. We assessed the impact of norovirus gastroenteritis on health care utilization in US subjects with a range of chronic medical conditions.

METHODS

We performed a retrospective cohort study using MarketScan data from July 2002 to December 2013, comparing the rates of emergency department visits, outpatient visits and hospitalizations among patients with chronic conditions (renal, cardiovascular, respiratory, immunocompromising, gastrointestinal, hepatic/pancreatic and neurological conditions and diabetes) with those in a healthy population. We estimated the rates of these outcomes due to norovirus gastroenteritis using an indirect modelling approach whereby cases of gastroenteritis of unknown cause and not attributed to a range of other causes were assumed to be due to norovirus.

RESULTS

Hospitalization rates for norovirus gastroenteritis were higher in all of the risk groups analyzed compared with data in otherwise healthy subjects, ranging from 3.2 per 10,000 person-years in persons with chronic respiratory conditions, to 23.1 per 10,000 person-years in persons with chronic renal conditions, compared to 2.1 per 10,000 among persons without chronic conditions. Over 51% of all norovirus hospitalizations occurred in the 37% of the population with some form of chronic medical condition. Outpatient visits for norovirus gastroenteritis were also increased in persons with chronic gastrointestinal or immunocompromising conditions.

CONCLUSION

Norovirus gastroenteritis leads to significantly higher rates of healthcare utilization in patients with a chronic medical condition compared to patients without any such condition.

Increased and prolonged human norovirus infection in RAG2/IL2RG deficient gnotobiotic pigs with severe combined immunodeficiency

Application of genetically engineered (GE) large animals carrying multi-allelic modifications has been hampered by low efficiency in production and extended gestation period compared to rodents. Here, we rapidly generated RAG2/IL2RG double knockout pigs using direct injection of CRISPR/Cas9 system into developing embryos. RAG2/IL2RG deficient pigs were immunodeficient, characterized by depletion of lymphocytes and either absence of or structurally abnormal immune organs. Pigs were maintained in gnotobiotic facility and evaluated for human norovirus (HuNoV) infection. HuNoV shedding lasted for 16 days in wild type pigs, compared to 27 days (until the end of trials) in RAG2/IL2RG deficient pigs. Additionally, higher HuNoV titers were detected in intestinal tissues and contents and in blood, indicating increased and prolonged HuNoV infection in RAG2/IL2RG deficient pigs and the importance of lymphocytes in HuNoV clearance. These results suggest that GE immunodeficient gnotobiotic pigs serve as a novel model for biomedical research and will facilitate HuNoV studies.

Therapeutic and Prophylactic Potential of Morama (Tylosema esculentum): A Review

Tylosema esculentum (morama) is a highly valued traditional food and source of medicine for the San and other indigenous populations that inhabit the arid to semi-arid parts of Southern Africa. Morama beans are a rich source of phenolic acids, flavonoids, certain fatty acids, non-essential amino acids, certain phytosterols, tannins and minerals. The plant's tuber contains griffonilide, behenic acid and starch. Concoctions of extracts from morama bean, tuber and other local plants are frequently used to treat diarrhoea and digestive disorders by the San and other indigenous populations. Information on composition and bioactivity of phytochemical components of T. esculentum suggests that the polyphenol-rich extracts of the bean testae and cotyledons have great potential as sources of chemicals that inhibit infectious microorganisms (viral, bacterial and fungal, including drug-resistant strains), offer protection against certain non-communicable diseases and promote wound healing and gut health. The potential antinutritional properties of a few morama components are also highlighted. More research is necessary to reveal the full prophylactic and therapeutic potential of the plant against diseases of the current century. Research on domestication and conservation of the plant offers new hope for sustainable utilisation of the plant.

Norovirus vaccines and potential antinorovirus drugs: recent advances and future perspectives

Human noroviruses (HuNoVs) are a leading cause of acute, nonbacterial gastroenteritis worldwide. The lack of a cell culture system and smaller animal model has delayed the development and commercial availability of vaccines and antiviral drugs. Current vaccines rely on recombinant capsid proteins, such as P particles and virus-like particles (VLPs), which have been promising in clinical trials. Anti-HuNoV drug development is another area of extensive research, including currently available antiviral drugs for other viral pathogens. This review will provide an overview of recent advances in vaccine and antiviral development. The implication of recent advances in HuNoV cell culture for improving vaccine and antiviral development is also discussed.