Incidence and characteristics of norovirus-associated benign convulsions with mild gastroenteritis, in comparison with rotavirus ones.

BACKGROUND AND PURPOSE: Rotavirus was detected in 40-50% of patients with benign convulsions with mild gastroenteritis (CwG) before the rotavirus vaccine was introduced in late 2000. However, the rate of rotavirus positivity has decreased since 2010 while the prevalence of norovirus has gradually increased. We investigated the incidence of norovirus-associated CwG during a recent 3-year period and additionally compared the characteristics of norovirus-associated CwG with those of rotavirus-associated CwG. METHODS: The medical records of CwG patients admitted to our hospital between March 2014 and February 2017 were reviewed, including the results of stool virus tests. For comparing norovirus- and rotavirus-associated CwG, data obtained between March 2005 and February 2014 that included sufficient numbers of patients with rotavirus-associated CwG were additionally reviewed. Data were collected on clinical characteristics (age, sex, seasonal distribution, enteric symptoms, and the interval to seizure onset), seizure characteristics (frequency, duration, type, and electroencephalographic findings), and laboratory findings. RESULTS: CwG was diagnosed in 42 patients during the 3-year study period. Stool viruses were checked in 40 (95.2%) patients and were detected in 32 (80.0%) patients. Norovirus genogroup II was detected in 27 (67.5%) of the 40 patients, rotavirus was detected in 3 patients, and adenovirus was detected in 2 patients. In total, 140 CwG patients were enrolled between March 2005 and February 2017. The patients with norovirus-associated CwG (N = 44) and rotavirus-associated CwG (N = 26) were aged 18.66 ±â€¯5.57 and 19.31 ±â€¯7.37 months (mean ±â€¯standard deviation), respectively (P > 0.05). Norovirus-associated CwG was less prevalent than rotavirus-associated CwG during spring (13.6% vs. 34.6%, P = 0.04), while the prevalence of both types of CwG peaked during winter (63.6% and 46.2%, respectively). Vomiting was more prevalent in norovirus- than rotavirus-associated CwG (97.7% vs. 80.8%, P = 0.02) and the interval between enteric symptom onset and seizure onset was shorter in norovirus-associated CwG (2.00 ±â€¯1.06 vs. 2.58 ±â€¯1.21 days, P = 0.04). Most cases in both groups had seizures that lasted for less than 5 min (95.5% vs. 92.3%). Clustered seizures seemed to occur more frequently in the norovirus group (79.5% vs. 57.7%), although with borderline significance (P = 0.05). Posterior slowing was observed more frequently in norovirus-associated CwG (34.9% vs. 11.5%, P = 0.03). CONCLUSION: The most common viral pathogen of CwG was norovirus during the analyzed 3-year period, with an incidence of 67.5%. In comparison with rotavirus-associated CwG, norovirus-associated CwG was less frequent during spring, more frequently seen with vomiting, had a shorter interval from enteric symptom onset to seizure onset, and more frequently showed posterior slowing in electroencephalography.

Melatonin modulates the autophagic response in acute liver failure induced by the rabbit hemorrhagic disease virus.

Autophagy is an important survival pathway and participates in the host response to infection. Beneficial effects of melatonin have been previously reported in an animal model of acute liver failure (ALF) induced by the rabbit hemorrhagic disease virus (RHDV). This study was aimed to investigate whether melatonin protection against liver injury induced by the RHDV associates to modulation of autophagy. Rabbits were infected with 2 × 10(4) hemagglutination units of a RHDV isolate and received 20 mg/kg melatonin at 0, 12, and 24 hr postinfection. RHDV induced autophagy, with increased expression of beclin-1, ubiquitin-like autophagy-related (Atg)5, Atg12, Atg16L1 and sequestrosome 1 (p62/SQSTM1), protein 1 light chain 3 (LC3) staining, and conversion of LC3-I to autophagosome-associated LC3-II. These effects reached a maximum at 24 hr postinfection, in parallel to extensive colocalization of LC3 and lysosome-associated membrane protein (LAMP)-1. The autophagic response induced by RHDV infection was significantly inhibited by melatonin administration. Melatonin treatment also resulted in decreased immunoreactivity for RHDV viral VP60 antigen and a significantly reduction in RHDV VP60 mRNA levels, oxidized to reduced glutathione ratio (GSSG/GSH), caspase-3 activity, and immunoglobulin-heavy-chain-binding protein (BiP) and CCAAT/enhancer-binding protein homologous protein (CHOP) expression. Results indicate that, in addition to its antioxidant and antiapoptotic effects, and the suppression of ER stress, melatonin induces a decrease in autophagy associated with RHDV infection and inhibits RHDV RNA replication. Results obtained reveal novel molecular pathways accounting for the protective effect of melatonin in this animal model of ALF.

Nosocomial diarrhea: a review of pathophysiology, etiology, and treatment strategies.

Diarrhea is a frequent complication among hospitalized patients. Nosocomial diarrhea is generally diagnosed as increased frequency and decreased consistency of stools developing after 72 hours of hospitalization. The causes of nosocomial diarrhea may be infectious or noninfectious. Noninfectious etiologies occur most commonly, and are often adverse effects of medications or enteral nutrition therapies. Infectious etiologies are most concerning and include Clostridium difficile and norovirus. Patients with nosocomial diarrhea should be placed in isolation with contact precautions in place until the presence of C difficile infection is determined. Irrespective of etiology, diarrhea can cause serious complications in hospitalized patients, including malnutrition, hemodynamic instability, metabolic acidosis, and potentially fatal pseudomembranous colitis. This article reviews nosocomial diarrhea, including its pathophysiology, infectious and noninfectious causes, and treatment strategies based on identified cause.

Gastroenteritis in childhood: a retrospective study of 650 hospitalized pediatric patients.

BACKGROUND: Acute diarrhea continues to be an important cause of hospitalization in young children, and deaths still occur as a result. We reviewed a large cohort of hospitalized children affected by gastroenteritis. The hypothesis of our study was that clinical characteristics and a limited set of laboratory data can differentiate between the different causative pathogens of diarrhea. METHODS: A chart review was performed of 650 patients with pathogen-proven diarrhea treated between April 2005 and May 2008 in the children's hospital of the University of Würzburg. Clinical presentation at the time of admission and during hospital stay, laboratory findings, stool pathogen results, and epidemiological data were collected and compared. A severity score was generated. RESULTS: Rotavirus was the most common gastroenteritis pathogen identified, followed by norovirus, adenovirus and Salmonella spp. Nosocomial infections were caused most commonly by norovirus. Rotavirus was the most common agent when there was simultaneous detection of two or more viruses. Rotavirus infections were significantly more severe, with a higher frequency of diarrhea and elevated liver enzymes. Infections due to Salmonella spp showed significantly higher values for C-reactive protein, erythrocyte sedimentation rate, and body temperature. A seasonal distribution was noted, with the peak for rotaviruses/noroviruses in winter/spring, the peak for adenoviruses in November/December, and the peak for Salmonella spp in the summer months. Younger children and toddlers had significantly higher gastroenteritis and airway inflammation scores. Of note, respiratory symptoms and parameters of systemic inflammation differed between the different pathogens. CONCLUSIONS: Gastroenteritis is a common reason for hospital admission in previously healthy children during the first years of life. Rotaviruses were found to be the most common pathogens in our cohort. On the basis of clinical and laboratory parameters it appears possible to distinguish between the different causative agents. This may have implications for hospital hygiene management and for the identification of predictive markers of a severe course.

Norwalk virus does not replicate in human macrophages or dendritic cells derived from the peripheral blood of susceptible humans.

Human noroviruses are difficult to study due to the lack of an efficient in vitro cell culture system or small animal model. Murine norovirus replicates in murine macrophages (MPhi) and dendritic cells (DCs), raising the possibility that human NoVs might replicate in such human cell types. To test this hypothesis, we evaluated DCs and MPhi derived from monocyte subsets and CD11c(+) DCs isolated from peripheral blood mononuclear cells of individuals susceptible to Norwalk virus (NV) infection. These cells were exposed to NV and replication was evaluated by immunofluorescence and by quantitative RT-PCR. A few PBMC-derived DCs expressed NV proteins. However, NV RNA did not increase in any of the cells tested. These results demonstrate that NV does not replicate in human CD11c(+) DCs, monocyte-derived DCs and MPhi, but abortive infection may occur in a few DCs. These results suggest that NV tropism is distinct from that of murine noroviruses.

Epidemiology and clinical peculiarities of norovirus and rotavirus infection in hospitalized young children with acute diarrhea in Taiwan, 2009.

BACKGROUND/PURPOSE: Acute diarrhea is one of the most common morbidities in pediatrics worldwide. We conducted a study to investigate the incidence of norovirus in young children hospitalized with acute diarrhea in Taiwan and its clinical peculiarity compared with rotavirus gastroenteritis. METHODS: Between January and December, 2009, patients younger than 5 years and admitted to hospital with acute diarrhea were randomly selected; and their stool samples were collected and tested for presence of rotavirus and norovirus by enzyme immunoassay and reverse transcription-polymerase chain reaction, respectively. The clinical manifestations and laboratory findings of the enrolled patients were analyzed. RESULTS: A total of 989 cases were enrolled with a mean age of 21.6 ± 13.7 months and a male proportion of 56.0%. Rotavirus and norovirus was detected in 20.2% and 14.6% of all patients, respectively. Genogroup II was the predominant strain of norovirus (80.6%). Children aged 6-36 months accounted for the majority of patients positive for rotavirus and norovirus (73.0% and 81.3%, respectively). The incidences of norovirus and rotavirus infection were higher during winter and early spring. Most patients with rotavirus and norovirus diarrhea experienced vomiting (74.9%vs. 74.8%, respectively) and fever (94.7%vs. 71.3%, respectively). CONCLUSION: Most young diarrheal patients presenting with vomiting were likely to have norovirus or rotavirus infection. Patients with norovirus diarrhea experienced an absence of, or low-grade fever and longer duration of vomiting compared with those positive for rotavirus infection. A family history of current gastroenteritis may suggest the possibility of norovirus infection.

Cysteine protease activation and apoptosis in Murine norovirus infection.

BACKGROUND: Noroviruses are the leading cause of viral gastroenteritis. Because a suitable in vitro culture system for the human virus has yet to be developed, many basic details of the infection process are unknown. Murine norovirus (MNV) serves as a model system for the study of norovirus infection. Recently it was shown that infection of RAW 264.7 cells involved a novel apoptotic pathway involving survivin. RESULTS: Using a different set of approaches, the up-regulation of caspases, DNA condensation/fragmentation, and membrane blebbing, all of which are markers of apoptosis, were confirmed. Live cell imaging and activity-based protein profiling showed that activation of caspase-like proteases occurred within two hours of infection, followed by morphological changes to the cells. MNV infection in the presence of caspase inhibitors proceeded via a distinct pathway of rapid cellular necrosis and reduced viral production. Affinity purification of activity-based protein profiling targets and identification by peptide mass fingerprinting showed that the cysteine protease cathepsin B was activated early in infection, establishing this protein as an upstream activator of the intrinsic apoptotic pathway. CONCLUSION: This work adds cathepsin B to the noncanonical programmed cell death induced by MNV, and provides data suggesting that the virus may induce apoptosis to expand the window of time for viral replication. This work also highlights the significant power of activity-based protein profiling in the study of viral pathogenesis.

Genetic susceptibility to symptomatic norovirus infection in Nicaragua.

Host genetic resistance to Norovirus (NoV) has been observed in challenge and outbreak studies in populations from Europe, Asia, and USA. In this study, we have investigated if histo-blood group antigens can predict susceptibility to diarrhea caused by NoV in Nicaragua, Central America, and if this can be reflected in antibody-prevalence and titer to NoV among individuals with different histo-blood group antigen phenotypes. Investigation of 28 individuals infected with NoV and 131 population controls revealed 6% of non-secretors in the population and nil non-secretors among patients infected with NoV, suggesting that non-secretors may be protected against NoV disease in Nicaragua. Surprisingly, 25% of the population was Lewis negative (Le(a-b-)). NoV infections with genogroup I (GI) and GII occurred irrespective of Lewis genotype, but none of the Lewis a positive (Le(a + b-)) were infected. The globally dominating GII.4 virus infected individuals of all blood groups except AB (n = 5), while the GI viruses (n = 4) infected only blood type O individuals. Furthermore, O blood types were susceptible to infections with GI.4, GII.4, GII.7, GII.17, and GII.18-Nica viruses, suggesting that secretors with blood type O are susceptible (OR = 1.52) and non-secretors resistant. The overall antibody-prevalence to NoV GII.3 VLP was 62% with the highest prevalence among blood type B carriers (70%) followed by A (68%) and O (62%). All four investigated individuals carrying blood type AB were antibody-negative. Among secretors, 63% were antibody-positive compared to 33% among non-secretors (P = 0.151). This study extends previous knowledge about the histo-blood group antigens role in NoV disease in a population with different genetic background than North American and European.

Quantitative detection of norovirus excretion in pediatric patients with cancer and prolonged gastroenteritis and shedding of norovirus.

Although chronic courses of norovirus infection have been described in immunocompromised patients, little is known about noroviral shedding and correlation with clinical symptoms in these patients. In this report, the quantitative courses of norovirus excretion in nine pediatric patients with hematologic and oncologic disorders and prolonged gastroenteritis were investigated. In a retrospective study multiple fecal samples from nine pediatric cancer patients were examined by a one-step real-time PCR. Clinical data of the patients were reviewed and virological data were correlated with clinical symptoms. All nine patients presented with prolonged illness and prolonged noroviral shedding. Vomiting and diarrhea were associated with high norovirus concentrations and norovirus excretion declined slowly in the patients. Retrospectively, initial PCR-testing for norovirus was performed with a median of 7 days after onset of symptoms. This finding hints at the difficulty of obtaining early diagnosis of the infection in these children. The patients were shedding high norovirus concentration over a long period of time. Results of sequential quantitative PCR-testing for norovirus correlated with clinical symptoms. Both clinical symptoms and quantitative PCR-testings help to define the severity of norovirus infection and to estimate the risk for transmission. To prevent the spread of the disease, usage of virocidal disinfectants and isolation procedures should be maintained as long as patients are positive for noroviruses. Since vomiting is frequent in pediatric patients with oncological conditions, a screening program for rapid detection of norovirus infection in this group of patients should be considered.

Historical background and classification of caliciviruses and astroviruses.

Infections caused by caliciviruses, i.e., vesicular exanthema virus of swine were recognised as a major cause of economic loss in the 1930s. However, it was not until the application of electronmicroscopy in the 1970s that caliciviruses and astroviruses were recognised and proven to be a cause of diarrhoea and vomiting. The following review briefly describes the steps which have led to the development of diagnostic tests and enabled the characterization of several members of the Caliciviridae and Astroviridae. In the past five years this has culminated in the sequencing of their genomes and the expression of viral proteins. This in turn has led to the development of improved diagnostic tests e.g., RT-PCR and enzyme immunoassays, and may pave the way towards producing effective vaccines in the future.