A nationwide survey of norovirus-associated encephalitis/encephalopathy in Japan

Asymptomatic viruses detectable in saliva in the first year of life: a narrative review

Viral infections are common in children. Many can be asymptomatic or have delayed health consequences. In view of increasing availability of point-of-care viral detection technologies, with possible application in newborn screening, this review aimed to (1) identify potentially asymptomatic viruses detectable in infants under one year old, via saliva/nasopharyngeal swab, and (2) describe associations between viruses and long-term health conditions. We systematically searched Embase(Ovid), Medline(Ovid) and PubMed, then further searched the literature in a tiered approach. From the 143 articles included, 28 potentially asymptomatic viruses were identified. Our second search revealed associations with a range of delayed health conditions, with most related to the severity of initial symptoms. Many respiratory viruses were linked with development of recurrent wheeze or asthma. Of note, some potentially asymptomatic viruses are linked with later non-communicable diseases: adenovirus serotype 36 and obesity, Enterovirus-A71 associated Hand, Foot, Mouth Disease and Attention-Deficit Hyperactivity Disorder, Ebstein Barr Virus (EBV) and malignancy, EBV and multiple sclerosis, HHV-6 and epilepsy, HBoV-1 and lung fibrosis and Norovirus and functional gastrointestinal disorders. Our review identified many potentially asymptomatic viruses, detectable in early life with potential delayed health consequences, that could be important to screen for in the future using rapid point-of-care viral detection methods. IMPACT: Novel point-of-care viral detection technologies enable rapid detection of viruses, both old and emerging. In view of increasing capability to screen for viruses, this is the first review to explore which potentially asymptomatic viruses, that are detectable using saliva and/or nasopharyngeal swabs in infants less than one year of age, are associated with delayed adverse health conditions. Further research into detecting such viruses in early life and their delayed health outcomes may pave new ways to prevent non-communicable diseases in the future.

A nationwide survey of adenovirus-associated encephalitis/encephalopathy in Japan

BACKGROUND

Adenovirus is a major pathogen causing febrile illness among children. It may also cause acute encephalitis/encephalopathy. This study aimed to elucidate the clinical features of adenovirus-associated encephalitis/encephalopathy (AdVE) among children in Japan.

METHODS

A nationwide survey of children with AdVE was conducted. An initial survey was distributed among pediatricians to obtain information about children with AdVE treated between January 2014 and March 2019. A second survey was used to obtain the clinical information of children with AdVE from hospitals that responded to the initial survey and those identified from a literature search of the reported cases. We collected demographic data and information about symptoms of infection, neurological symptoms, laboratory parameters, treatment, and outcomes. Outcomes were determined using the Pediatric Cerebral Performance Category Score.

RESULTS

Clinical information was available for 23 children with a median age of 39 months. Two had preexisting neurological disorders and six had a history of febrile seizures. The outcome was good in 15 patients and poor in eight patients. Serum lactate dehydrogenase, glucose, and ammonia levels were higher among children with a poor outcome compared to those with a good outcome. Clinically mild encephalitis/encephalopathy with a reversible splenial lesion was the most common type (n = 8), followed by acute encephalopathy with biphasic seizures and late reduced diffusion (n = 7).

CONCLUSION

A prior history of febrile seizures was frequent in children with AdVE. Several different subtypes of acute encephalopathy were seen in children with AdVE, and the outcome was poor in those with acute encephalopathy with biphasic seizures and late reduced diffusion and hemorrhagic shock and encephalopathy syndrome. Elevated lactate dehydrogenase, glucose, and ammonia levels on admission were found to correlate with a poor outcome.

Norovirus-associated neurological manifestations: summarizing the evidence

Norovirus, a positive-stranded RNA virus, is one of the leading causes of acute gastroenteritis among all age groups worldwide. The neurological manifestations of norovirus are underrecognized, but several wide-spectrum neurological manifestations have been reported among infected individuals in the last few years. Our objective was to summarize the features of norovirus-associated neurological disorders based on the available literature. We used the existing PRISMA consensus statement. Data were collected from PubMed, EMBASE, Web of Science, and Scopus databases up to Jan 30, 2023, using pre-specified searching strategies. Twenty-one articles were selected for the qualitative synthesis. Among these, seven hundred and seventy-four patients with norovirus-associated neurological manifestations were reported. Most cases were seizure episodes, infection-induced encephalopathy, and immune-driven disorders. However, only a few studies have addressed the pathogenesis of norovirus-related neurological complications. The pathogenesis of these manifestations may be mediated by either neurotropism or aberrant immune-mediated injury, or both, depending on the affected system. Our review could help clinicians to recognize these neurological manifestations better and earlier while deepening the understanding of the pathogenesis of this viral infection.

A nationwide survey of human metapneumovirus-associated encephalitis/encephalopathy in Japan

BACKGROUND

As there have been no comprehensive reports of human metapneumovirus-associated encephalopathy (hMPVE), this study examined the clinical features of hMPVE in children in Japan.

METHOD

A nationwide survey of children with hMPVE was conducted using a structured research form. An initial survey asked pediatricians about children with hMPVE treated between 2014 and 2018. A second survey obtained patient information from hospitals that responded to the initial survey and those identified as having treated cases from a literature search. We collected demographic data, symptoms of hMPV infection, neurological symptoms, laboratory data, treatment, and outcomes. Outcomes were determined using the Pediatric Cerebral Performance Category Score.

RESULT

Clinical information was available for 16 children. Their median age was 37 months. Six had preexisting neurological disorders. The interval between the onsets of infection and hMPVE was 4 days. Outcomes were good in 11 patients and poor in 5. There were no significant differences in demographic data, neurological symptoms, or laboratory data between the patients with good and poor outcomes. The encephalopathy subtypes were acute encephalopathy with biphasic seizures and late reduced diffusion in 3, clinically mild encephalitis/encephalopathy with a reversible splenial lesion in 3, hemorrhagic shock and encephalopathy syndrome in 2, and others in 8.

CONCLUSION

The outcomes of children with hMPVE were not very different from those of acute encephalopathy due to other viruses. We found no factors associated with poor outcomes.

Brain Hypothermia Therapy and Targeted Temperature Management for Acute Encephalopathy in Children: Status and Prospects

In adult intensive care, brain hypothermia therapy (BHT) was reported to be effective in neuroprotection after resuscitation and cardiac arrest. By contrast, in neonatal intensive care, the pathophysiology of brain damage caused by hypoxic–ischemic encephalopathy (HIE) is attributed to circulatory disturbances resulting from ischemia/reperfusion, for which neonatal brain cryotherapy is used. The International Liaison Committee on Resuscitation, 2010, recommends cerebral cryotherapy for HIE associated with severe neonatal pseudoparenchyma death. The usefulness of BHT for neuroprotection in infants and children, especially in pediatric acute encephalopathy, is expected. Theoretically, BHT could be useful in basic medical science and animal experiments. However, there are limitations in clinical planning for treating pediatric acute encephalopathy. No international collaborative study has been conducted, and no clinical evidence exists for neuroprotection using BHT. In this review, we will discuss the pathogenesis of neuronal damage in hypoxic and hypoperfused brains; the history of BHT, its effects, and mechanisms of action; the success of BHT; cooling and monitoring methods of BHT; adverse reactions to BHT; literature on BHT. We will review the latest literature on targeted temperature management, which is used for maintaining and controlling body temperature in adults in intensive care. Finally, we will discuss the development of BHT and targeted temperature management as treatments for pediatric acute encephalopathy.

Seasonal Trends in the Prevalence and Incidence of Viral Encephalitis in Korea (2015-2019)

Viral infections are a common cause of encephalitis. This study investigated the relationship between the incidence of encephalitis and that of respiratory and enteric viral infections in all age groups from 2015 to 2019, using the Health Insurance Review and Assessment (HIRA) Open Access Big Data Platform. We identified monthly incidence patterns and seasonal trends using the autoregressive integrated moving average (ARIMA). The Granger causality test was used to analyze correlations between encephalitis incidence and the positive detection rate (PDR) at 1-month intervals. A total of 42,775 patients were diagnosed with encephalitis during the study period. The incidence of encephalitis was highest in the winter (26.8%). The PDRs for respiratory syncytial virus (HRSV) and coronavirus (HCoV) were associated with the trend in encephalitis diagnosis in all age groups, with a 1-month lag period. In addition, an association with norovirus was observed in patients aged over 20 years, and with influenza virus (IFV) in patients aged over 60 years. This study found that HRSV, HCoV, IFV, and norovirus tended to precede encephalitis by 1 month. Further research is required to confirm the association between these viruses and encephalitis.

Norovirus-associated White Matter Injury in a Term Newborn With Seizures

Neonatal seizures with white matter injury have been associated with rotavirus, enterovirus and parechovirus. Neurological symptoms caused by norovirus have been occasionally reported in older children. We describe a case of a neonate with seizures and white matter lesions, with detection of human norovirus in stool samples from the patient and her mother.

Epidemiology, Clinical Features, and Unusual Complications of Norovirus Infection in Taiwan: What We Know after Rotavirus Vaccines

Noroviruses (NoVs) are one of the emerging and rapidly spreading groups of pathogens threatening human health. A reduction in sporadic NoV infections was noted following the start of the COVID-19 pandemic, but the return of NoV gastroenteritis during the COVID-19 pandemic has been noted recently. Research in recent years has shown that different virus strains are associated with different clinical characteristics; moreover, there is a paucity of research into extraintestinal or unusual complications that may be associated with NoV. The genomic diversity of circulating NoVs is also complex and may vary significantly. Therefore, this short narrative review focuses on sharing the Taiwan experience of NoV infection including epidemiology, clinical features, and complications following suboptimal rotavirus immunization in Taiwan (after October 2006). We also highlight the unusual complications associated with NoV infections and the impacts of NoV infection during the COVID-19 pandemic in the literature for possible future research directions. To conclude, further research is needed to quantify the burden of NoV across the spectrum of disease severity in Taiwan. The evidence of the connection between NoV and the unusual complications is still lacking.

Norovirus: Facts and Reflections from Past, Present, and Future

Human Norovirus is currently the main viral cause of acute gastroenteritis (AGEs) in most countries worldwide. Nearly 50 years after the discovery of the "Norwalk virus" by Kapikian and colleagues, the scientific and medical community continue to generate new knowledge on the full biological and disease spectrum of Norovirus infection. Nevertheless, several areas remain incompletely understood due to the serious constraints to effectively replicate and propagate the virus. Here, we present a narrated historic perspective and summarize our current knowledge, including insights and reflections on current points of interest for a broad medical community, including clinical and molecular epidemiology, viral-host-microbiota interactions, antivirals, and vaccine prototypes. We also include a reflection on the present and future impacts of the COVID-19 pandemic on Norovirus infection and disease.

Development of a Tetraplex qPCR for the Molecular Identification and Quantification of Human Enteric Viruses, NoV and HAV, in Fish Samples

Human enteric viruses such as norovirus (NoV) and hepatitis A virus (HAV) are some of the most important causes of foodborne infections worldwide. Usually, infection via fish consumption is not a concern regarding these viruses, since fish are mainly consumed cooked. However, in the last years, raw fish consumption has become increasingly common, especially involving the use of seabass and gilthead seabream in dishes like sushi, sashimi, poke, and carpaccio. Therefore, the risk for viral infection via the consumption of raw fish has also increased. In this study, a virologic screening was performed in 323 fish specimens captured along the Portuguese coast using a tetraplex qPCR optimised for two templates (plasmid and in vitro transcribed RNA) to detect and quantify NoV GI, NoV GII and HAV genomes. A difference of approximately 1-log was found between the use of plasmid or in vitro transcribed RNA for molecular-based quantifications, showing an underestimation of genome copy-number equivalents using plasmid standard-based curves. Additionally, the presence of NoV genomic RNA in a pool of seabass brains was identified, which was shown to cluster with a major group of human norovirus sequences from genogroup I (GI.1) by phylogenetic analysis. None of the analysed fish revealed the presence of NoV GII or HAV. This result corroborates the hypothesis that enteric viruses circulate in seawater or that fish were contaminated during their transportation/handling, representing a potential risk to humans through raw or undercooked fish consumption.

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. In this article, we described 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.

Acute encephalopathy in children with tuberous sclerosis complex

Objective

We examined the clinical manifestations of acute encephalopathy (AE) and identify risk factors for AE in children with tuberous sclerosis complex (TSC).

Methods

The clinical data of 11 children with clinically diagnosed TSC associated with AE and 109 children with clinically diagnosed TSC alone aged 4 years or older were collected from 13 hospitals.

Results

Of the 11 children with AE, 5 had histories of febrile seizures (FS), and all had histories of febrile status epilepticus (FSE). AE developed within 24 h after fever onset in all children with seizures lasting 30 min or longer. All children developed coma after seizure cessation. Head magnetic resonance imaging (MRI) revealed widespread abnormalities in the cerebral cortex, subcortical white matter, corpus callosum, basal ganglia, and thalamus. One child died; seven had severe neurological sequelae; and the other three, mild sequelae. Logistic regression analysis revealed that a history of FSE was correlated with the development of AE.

Significance

AE in children with TSC was characterized by sudden onset after fever, followed by coma, widespread brain edema evident on MRI, and poor outcomes. A history of FSE was a risk factor for the development of AE.

Recent treatment patterns and variations for pediatric acute encephalopathy in Japan

BACKGROUND

Treatments for pediatric acute encephalopathy are largely empiric with limited evidence to support. This study investigated recent trends in clinical practice patterns for pediatric acute encephalopathy at a national level.

METHOD

Discharge records were extracted for children with acute encephalopathy for the fiscal years 2010-2015 using a national inpatient database in Japan. We ascertained the secular trends in medications, diagnostic and therapeutic procedures, healthcare costs, in-hospital mortality, and length of hospital stays (LOS), using mixed effect linear or logistic regression models. We also ascertained variations and clustering of the practice patterns across different hospitals using hierarchical cluster analyses.

RESULTS

A total of 4692 eligible inpatients were identified. From 2010 to 2015, we observed increasing trends in hospitalization costs, corticosteroid and edaravone use and a decreasing trend in LOS. Despite changes in treatments, the rates of home respiratory support and in-hospital mortality were constant during the study period. Hierarchical cluster analyses showed that 6 hospital groups showed largely different therapeutic strategies to the same disease regardless of mortality rates. Hospitals with more intensive treatment practices were likely to have higher mortality, while hospitals with less intensive treatment practices were likely to have the lower mortality. However, hospitals in one group (group 1) had less intensive treatment practice even though they had the highest mortality.

CONCLUSIONS

We provided novel insights into the recent trends in treatments for pediatric acute encephalopathy. Therapeutic strategies varied between hospitals, suggesting the importance of pursuing evidence-based treatment strategy and promoting standardized practices to pediatric acute encephalopathy.