Rotavirus gastroenteritis and central nervous system (CNS) infection: characterization of the VP7 and VP4 genes of rotavirus strains isolated from paired fecal and cerebrospinal fluid samples from a child with CNS disease

Increased Risk of Neurological Disease Following Pediatric Rotavirus Infection: A Two-Center Case-Control Study

BACKGROUND

Whether pediatric rotavirus infection is associated with extraintestinal complications remains unknown.

METHODS

We conducted a case-control study to investigate the incidences and risks of rotavirus-associated extraintestinal complications in hospitalized newborns, infants, and children younger than 5 years.

RESULTS

A total of 1325 young inpatients with rotavirus infection (754 male and 539 newborns) and 1840 controls without rotavirus infection (1035 male and 836 newborns) were included. The incidences of neurological disease were higher among rotavirus individuals compared with controls: newborns, 7.24% (39/539) versus 2.87% (24/836), P < .001; infants and young children, 19.59% (154/786) versus 12.35% (124/1004), P < .001. The associated odd ratios (ORs) for neurological disease frequency following rotavirus infection was 2.64 (95% confidence interval [CI], 1.57-4.44) for newborns and 1.73 (95% CI, 1.34-2.24) for infants and young children, which increased to 2.56 (95% CI, 1.57-4.18) in case-control (1:1) matching analysis and 1.85 (95% CI, 1.41-2.42) in confounder adjustment. Rotavirus infection was associated with other extraintestinal complications, depending on study population and disease severity. Outcome analysis revealed rotavirus infection and its consequences had a significant impact on hospitalization and discharge.

CONCLUSIONS

Rotavirus exposure was associated with a spectrum of extraintestinal complications, particularly neurological disease. Rotavirus infection and subsequent consequences resulted in poor clinical outcomes.

Rotavirus infection-associated central nervous system complications: clinicoradiological features and potential mechanisms

Despite the introduction of vaccines in 2006, rotavirus remains one of the most common causes of pediatric gastroenteritis worldwide. While many studies have conclusively shown that rotavirus infection causes gastroenteritis and is associated with various extraintestinal manifestations including central nervous system (CNS) complications, extraintestinal manifestations due to rotavirus infection have been relatively overlooked. Rotavirus infection-associated CNS complications are common in children and present with diverse clinicoradiological features. Rotavirus infection-associated CNS complications can be classified based on clinical features and brain magnetic resonance imaging findings, particularly lesion location on diffusion-weighted imaging. Common clinicoradiological features of rotavirus infection-associated CNS complications include: (1) benign convulsions with mild gastroenteritis; (2) acute encephalopathies/encephalitis, such as mild encephalopathy with a reversible splenial lesion, acute encephalopathy with biphasic seizures and late reduced diffusion, and acute necrotizing encephalopathy; (3) acute cerebellitis; and (4) neonatal rotavirus-associated leukoencephalopathy. The precise mechanism underlying the development of these complications remains unknown despite a number of clinical and laboratory studies. Here we review the diverse clinicoradiological features of rotavirus infection-associated CNS complications and propose a hypothesis of their pathophysiology.

A recombinant murine-like rotavirus with Nano-Luciferase expression reveals tissue tropism, replication dynamics, and virus transmission

Rotaviruses (RVs) are one of the main causes of severe gastroenteritis, diarrhea, and death in children and young animals. While suckling mice prove to be highly useful small animal models of RV infection and pathogenesis, direct visualization tools are lacking to track the temporal dynamics of RV replication and transmissibility in vivo. Here, we report the generation of the first recombinant murine-like RV that encodes a Nano-Luciferase reporter (NLuc) using a newly optimized RV reverse genetics system. The NLuc-expressing RV was replication-competent in cell culture and both infectious and virulent in neonatal mice in vivo. Strong luciferase signals were detected in the proximal and distal small intestines, colon, and mesenteric lymph nodes. We showed, via a noninvasive in vivo imaging system, that RV intestinal replication peaked at days 2 to 5 post infection. Moreover, we successfully tracked RV transmission to uninoculated littermates as early as 3 days post infection, 1 day prior to clinically apparent diarrhea and 3 days prior to detectable fecal RV shedding in the uninoculated littermates. We also observed significantly increased viral replication in Stat1 knockout mice that lack the host interferon signaling. Our results suggest that the NLuc murine-like RV represents a non-lethal powerful tool for the studies of tissue tropism and host and viral factors that regulate RV replication and spread, as well as provides a new tool to facilitate the testing of prophylactic and therapeutic interventions in the future.

Rotavirus viroplasm biogenesis involves microtubule-based dynein transport mediated by an interaction between NSP2 and dynein intermediate chain

Rotaviruses are the causative agents of severe and dehydrating gastroenteritis in children, piglets, and many other young animals. They replicate their genomes and assemble double-layered particles in cytoplasmic electron-dense inclusion bodies called 'viroplasms'. The formation of viroplasms is reportedly associated with the stability of microtubules. Although material transport is an important function of microtubules, whether and how microtubule-based transport influences the formation of viroplasms is still unclear. Here, we demonstrate that the small viroplasms move and fuse in living cells. We show that microtubule-based dynein transport affects rotavirus infection, viroplasm formation, and the assembly of transient enveloped particles (TEPs) and triple-layered particles (TLPs). The dynein intermediate chain (DIC) is shown to localize in the viroplasm and to interact directly with non-structural protein 2 (NSP2), indicating that DIC is responsible for connecting the viroplasm to dynein. The WD40 repeat domain of DIC regulates the interaction between DIC and NSP2, and the knockdown of DIC inhibited rotaviral infection, viroplasm formation, and the assembly of TEPs and TLPs. Our findings show that rotavirus viroplasms hijack dynein transport for fusion events, required for maximal assembly of infectious viral progeny. This study provides novel insights into the intracellular transport of viroplasms, which is involved in their biogenesis. Importance Because the viroplasm is the viral factory for rotavirus replication, viroplasm formation undoubtedly determines the effective production of progeny rotavirus. Therefore, understanding the virus-host interactions involved in the biogenesis of the viroplasm is critical for the future development of prophylactic and therapeutic strategies. Previous studies have reported that the formation of viroplasms is associated with the stability of microtubules, whereas little is known about its specific mechanism. Here, we demonstrate that rotavirus viroplasm formation takes advantage of microtubule-based dynein transport mediated by an interaction between NSP2 and DIC. These findings provide new insight into the intracellular transport of viroplasms.

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.

Rotavirus-associated seizures and reversible corpus callosum lesion

Rotavirus is a non-enveloped double-stranded RNA virus that causes severe gastroenteritis in children, but complications are rarely reported. Some reports have shown that rotavirus can induce diverse complications of the central nervous system, such as seizures, encephalopathy with a reversible splenial lesion, encephalitis, cerebral white matter abnormalities, and cerebellitis. Here, we present a 2-year-old patient with seizures, who had an isolated splenial lesion in the corpus callosum on neuroimaging, and the rotavirus antigen detected in faeces.

Rotavirus antigenemia as a common event among children hospitalised for severe, acute gastroenteritis in Belém, northern Brazil

Background

Rotavirus antigenemia and RNAemia (the presence of rotavirus RNA in serum) have been commonly identified among paediatric patients with acute gastroenteritis. In this study we examined the association between rotavirus antigenemia and clinical features, and sought to determine the genotypes of rotaviruses detected in paired stool and serum samples.

Methods

Paired stool and serum samples were obtained from children hospitalised for acute gastroenteritis in Belém, Brazil, between June 2012 and June 2015. The 20-point Vesikari scoring system was used to assess the disease severity upon a retrospective medical record review. Stool and serum samples were primarily screened for the presence of rotavirus antigen using a commercial ELISA assay. The rotavirus isolates from stool and serum samples were genotyped by using the classical reverse-transcriptase polymerase chain reaction (RT-PCR) and/or through nucleotide sequencing of VP4 and VP7 genes. Viral load was estimated using real-time RT-PCR.

Results

In total rotavirus antigen was detected in 109 (24.2%) stool samples from 451 children, whereas antigenemia occurred in 38.5% (42/109) of these patients. We demonstrated that patients positive for rotavirus RNA in paired stool and serum samples were more likely to have a higher frequency of vomiting episodes in a 24-h period (p = 0.0035). Our findings also suggested that children not vaccinated against rotavirus are more likely to develop antigenemia, as compared to those given at least one vaccine dose (p = 0.0151). G12P [8] and G2P [4] genotypes were predominant throughout the study period, accounting for 52.3% (57/109) and 27.5% (30/109) of the typed isolates, respectively. Ten stool-serum pairs could be typed for VP4 and VP7 genes. Seven of these pairs showed concordant results with G2P [4] genotype being detected in stool and serum samples, whereas discrepancies between genotypes (G2P [4]/G2P[NT] and G12P [8]/G2P[NT]) were seen in three pairs.

Conclusions

Rotavirus antigenemia and RNAemia occur in a significant number of children hospitalised for acute gastroenteritis in Belém, Brazil, and may contribute to a greater disease severity, particularly translated into a greater number of vomiting episodes. This study documented a high concordance of genotypes detected in a subgroup of paired stool and serum samples.

Electronic supplementary material

The online version of this article (10.1186/s12887-019-1535-2) contains supplementary material, which is available to authorized users.

Evaluation of benign afebrile convulsions in 16 children with rotavirus gastroenteritis

In this study, we aimed to investigate the demographic, clinical, and laboratory findings of the patients hospitalized with rotavirus gastroenteritis-related afebrile seizure, retrospectively. The study population consisted of 16 patients (9 girls and 7 boys) with a mean age of 13.81 ± 5.98 months (age range 6-26). The male/female ratio was 0.77. None of the patients had any psychomotor developmental retardation. Neurological examinations of all the patients were normal. There were 7 patients with generalized tonic (43.75%), 8 generalized tonic-clonic (50%), and 1 focal seizure (6.25%). The duration of the seizures varied at a range of 2-7 min (mean 3.68 ± 1.35 min). The period between the onset of the clinical findings of the rotavirus infection and the occurrence of the seizures was ranged from 12 to 48 h (mean 31.5 ± 12.2 h). The prognosis of the rotavirus gastroenteritis-related afebrile convulsions was generally benign. Rotavirus infection should be taken into consideration in infants with gastroenteritis and afebrile convulsions.

Rotavirus NSP486-175 interacts with H9c2(2-1) cells in vitro, elevates intracellular Ca2+ levels and can become cytotoxic: a possible mechanism for extra-intestinal pathogenesis

Rotavirus (RV) is the predominant cause of infantile gastroenteritis with multiple pathogenic factors, among which enterotoxin NSP4 is the most significant factor. NSP4 has been shown to induce elevation of the intracellular calcium concentration, alteration of the cytoskeleton organization, and cytopathic effect among other processes. However, increasing evidence suggests that RVs can escape from the gastrointestinal tract and invade other organs and tissues to cause extra-intestinal diseases. In this study, we investigated whether NSP4 has a pathogenic effect on extra-intestinal cells and examined possible molecular mechanisms in vitro. Our results showed that NSP4_86-175 has important functions in increasing intracellular Ca²⁺ concentration, altering actin cytoskeleton organization and inducing cellular damage in H9c2(2-1) cells. Blockade of the integrin α2 receptor using a specific antibody attenuated the increase of intracellular Ca²⁺ concentration and alleviated the observed cytopathic effects, suggesting that integrin α2 may be a receptor for NSP4_86-175. Collectively, these results indicate that extracellular NSP4_86-175 can induce elevation of the intracellular Ca²⁺ concentration, cause cytotoxic changes, and disrupt the actin cytoskeleton in H9c2(2-1) cells, which may constitute a possible mechanism for RV extra-intestinal pathogenesis.

Frequency of adenoviruses, rotaviruses and noroviruses among diarrhea samples collected from infants of zabol, southeastern iran

Background:

Viruses are one of the major reasons of gastrointestinal disease worldwide, and commonly infect children less than five years of age in developing countries.

Objectives:

The current study aimed to determine the frequency of adenoviruses, rotaviruses and noroviruses among diarrhea samples collected from infants of Zabol, south-east of Iran. This study is the first investigation of adenoviruses, rotaviruses and noroviruses among diarrhea samples in Zabol.

Patients and Methods:

In this study, eighty-two diarrhea stool samples were collected from infants aged < 1 to 12 months admitted to the hospital, internal laboratory and central laboratory of Zabol, Iran. All samples were subjected to the rapid immunochromatography assay.

Results:

The results showed that the frequency of rotaviruses, adenoviruses and noroviruses among infants with diarrhea were 70.20%, 20.30% and 9.50%, respectively. There were 50 subjects aged one to five months and 2 subjects aged nine to twelve months. The results of geographical distribution showed that the number of infants living in rural and urban areas with these viruses were 50 and 32, respectively. Rotaviruses were most common in rural and urban infants with 42 and 10 cases, respectively. Regarding the feeding patterns of infants with diarrhea, mixed feeding and breast feeding were found in 51 and 31 cases, respectively.

Conclusions:

In conclusion, the results of our study showed that the major viral pathogens that caused infantile diarrhea in Zabol city were rotaviruses followed by adenoviruses and noroviruses. The results of our study can useful for prosperous control of infantile diarrhea.

Systemic rotavirus infection

A new paradigm of rotavirus disease is emerging and rotavirus infection is no longer considered to be localized and confined to the GI tract. New evidence indicates that rotavirus infection is systemic. Viral antigen and infectious virus frequently enter the circulation in both children and animal model systems. Clinical case reports of systemic sequelae to rotavirus infection in children continue to accumulate, suggesting involvement in systemic disease syndromes. The use of animal models is providing biological and molecular evidence for infection at peripheral sites. Thus, infection at peripheral sites may account for reports of systemic sequelae to rotavirus infection. The importance of systemic sequelae and the ability of vaccination to prevent such sequelae remains to be determined.

Protective association between rotavirus vaccination and childhood seizures in the year following vaccination in US children

BACKGROUND

Rotavirus illness has been linked to childhood seizures. We investigated whether a protective association exists between receipt of rotavirus vaccine and being hospitalized or visiting the emergency department for seizures in the year after vaccination.

METHODS

We retrospectively analyzed a cohort of children born after 28 February 2006 (when rotavirus vaccine was licensed in the United States) and enrolled in the Vaccine Safety Datalink (VSD) through November 2009. Seizure rates from 4 to 55 weeks following last rotavirus vaccination were compared by vaccine exposure status (fully vaccinated and unvaccinated). A time-to-event analysis using a Cox proportional hazards model was performed, accounting for time-varying covariates. We calculated the relative incidence of seizure compared by vaccine exposure status during the postexposure interval.

RESULTS

Our cohort contained VSD data on 250 601 infants, including 186 502 children fully vaccinated (74.4%) and 64 099 (25.6%) not vaccinated with rotavirus vaccine. Rates of seizures were associated with rotavirus vaccination status. After adjusting for covariates (VSD site, age at last dose, sex, and calendar month of the index date), a statistically significant protective association was observed between a full course of rotavirus vaccination vs no vaccination for both first-ever seizures (risk ratio [RR] = 0.82; 95% confidence interval [CI], .73-.91) and all seizures (RR = 0.79; 95% CI, .71-.88).

CONCLUSIONS

A full course of rotavirus vaccination was statistically associated with an 18%-21% reduction in risk of seizure requiring hospitalization or emergency department care in the year following vaccination, compared with unvaccinated children. This reduction in childhood seizures complements the well-documented vaccine-related benefit of preventing US diarrhea hospitalizations.

Detection and characterisation of rotaviruses from children less than 5 years hospitalised with acute gastroenteritis in Nagercoil

Group A rotavirus continues to be the major cause of severe gastroenteritis in young children in developing countries. In this study, we report the prevalence and genotype of rotaviruses identified from children <5 years of age hospitalised with acute gastroenteritis from Nagercoil, Tamil Nadu from 2007-2010. From the 139 children included in the study, 71 samples (51%) were positive by ELISA and 65 samples were positive by PCR-based methods. G1P[8] (44.6%) was the most commonly identified genotype. In addition, we report detection of rotavirus in two of three CSF samples from children with seizures.

Towards a human rotavirus disease model

While the clinical importance of human rotavirus (RV) disease is well recognized and potent vaccines have been developed, our understanding of how human RV causes diarrhoea, vomiting and death remains unresolved. The fact that oral rehydration corrects electrolyte and water loss, indicates that enterocytes in the small intestine have a functional sodium-glucose co-transporter. Moreover, RV infection delays gastric emptying and loperamide appears to attenuate RV diarrhoea, thereby suggesting activation of the enteric nervous system. Serotonin (5-HT) receptor antagonists attenuate vomiting in young children with gastroenteritis while zinc and enkephalinase inhibitors attenuate RV-induced diarrhoea. In this review we discuss clinical symptoms, pathology, histology and treatment practices for human RV infections and compile the data into a simplified disease model.

Complications in hospitalized children with acute gastroenteritis caused by rotavirus: a retrospective analysis

Acute gastroenteritis (AGE) caused by rotavirus (RV) is a common disease among infants and toddlers, often leading to hospitalization and, in resource-poor countries, to death. However, little is known on specific complications of severe RV-positive (RV+) AGE and on the clinical course in chronically ill children. This was a retrospective analysis of data for children <5 years of age hospitalized due to AGE during six rotavirus seasons in three large German pediatric hospitals. The primary study end point was the incidence and type of complications in RV+ versus RV-negative (RV-) cases. A total of 6,884 episodes of AGE in hospitalized children aged <5 years were included in this analysis. Of the 4,880 stools tested for RV, 2,118 (43.4%) were RV+. Hypernatremia was significantly more common in RV+ AGE (P < 0.001) and was associated with severe disease, need for intensive care treatment, and longer duration of hospitalization. Metabolic disorders, particularly hypoglycemia, were more common in RV+ AGE. In contrast, symptoms such as respiratory infections, neurological, and abdominal symptoms were more common in children with RV- AGE.

CONCLUSIONS

Hypernatremia is a specific complication of RV+ AGE. RV would therefore appear to be the cause of infant toxicosis, the traditional descriptive term for severe dehydration and clinical deterioration following AGE.

Case report: detection of rotavirus RNA in the cerebrospinal fluid of a child with rotavirus gastroenteritis and meningism

Although case reports have described detection of rotavirus (RV) in extraintestinal sites such as the liver, kidney, and central nervous system (CNS) of children with RV gastroenteritis, CNS localization in RV infection seems to be rare. RT-PCR and nucleotide sequencing detected a G1P[8] strain in the stool and cerebrospinal fluid (CSF) samples of a patient with concurrent RV-associated enteritis and CNS signs. Upon sequence analysis, the viruses detected in the CSF was identical to the virus detected in the stools. In the VP7- and VP4-based phylogenetic dendograms the strain clustered within the G1-Ic sub-lineage and the P[8]-III lineage. This study supports the hypothesis that RV infection was able to spread from the intestinal tract to the CNS, and likely played a role in the onset of neurological disease.

Rotavirus infection: an update on management and prevention

Rotavirus infection is the most common cause of severe diarrhea disease in infants and young children worldwide and continues to have a major global impact on childhood morbidity and mortality. Vaccination is the only control measure likely to have a significant impact on the incidence of severe dehydrating rotavirus disease. Rotavirus vaccines have reduced the burden of rotavirus disease in the United States. Long-term monitoring will need to continue to assess the effects of rotavirus immunization programs and epidemiologic strain surveillance is necessary to determine whether changes in strain ecology will affect the rotavirus vaccine effectiveness and whether rotaviruses with the ability to evade vaccine immunity emerge.

Norovirus RNA in the blood of a child with gastroenteritis and convulsions--A case report

Potential extra-intestinal spread is an important issue in understanding the pathogenesis of NoV disease. A previously healthy 14-month-old boy was admitted to the Pediatric Emergency Department of the University-Hospital of Parma, Italy, for afebrile convulsions in a gastroenteritis episode. Bacterial culture and microscopic examination on cerebrospinal fluid (CSF) yielded negative results as well as PCRs and reverse-transcription PCRs (RT-PCRs) for neurotropic viruses performed either on CSF or plasma. Stools were subjected to electron microscopy and conventional cell culture, yielding negative results. NoV was found in stools and plasma by nested RT-PCR targeting the NoV polymerase gene. The nucleotide sequences obtained from the two specimens showed 100% identity, demonstrating that the strain invading the blood stream was from the intestine, and, in comparison with GenBank sequences, they belonged to NoV genotype GII.4, "2006b" variant. The child had no abnormal electrolyte balance and no fever that could justify seizures, encouraging the hypothesis that NoV could be the cause of the neurologic disorder. These findings further induce to review the current concept of human NoV focused on intestinal infection.

Benign infantile seizures with mild gastroenteritis: study of 22 patients

PURPOSE

To analyze the electroclinical features, aetiology and outcome in patients with normal neurological examination and psychomotor development who presented seizures during a mild gastroenteritis (MG).

PATIENTS AND METHODS

Evaluation of the clinical charts of 22 patients who were assessed in the Neurology Department, Hospital Nacional de Pediatría Prof. Dr. JP Garrahan between 1999 and 2007.

RESULTS

Twelve patients were boys and 10 were girls, the age of onset ranged from 5 to 26 months, and the median age was 10 months. Rotavirus antigen test in stool was positive in 9 of 18 studied patients. The seizures were brief, focal with secondary generalization in 15 patients (68.5%), apparently generalized in 5 (22.5%) and focal in two (9%). Seven of the patients (35%) had more than one seizure in 24h. The interictal EEG was normal in all patients. Neuroradiological studies were performed in 19 patients with a normal result. No patient was put on long-term treatment with antiepileptic drugs. Four patients had subsequent mild gastroenteritis and two of them presented convulsions during the disease. After between 12 and 67 months of follow-up, all patients had normal psychomotor development and neurological examination.

CONCLUSIONS

In this study we confirmed the association of benign infantile seizures (BIS) and MG with or without rotavirus. The identification of this entity allows avoiding unnecessary complementary studies and treatment with antiepileptic drugs.

A case of meningoencephalitis associated with G1P[8] rotavirus infection in a Japanese child

We report the case of a 2-y, 11-month-old boy with G1P[8] rotavirus infection accompanied by acute meningoencephalitis. Substitutions in both the VP4 and VP7 genes were found in the identified strain. A commonly circulating G1P[8] rotavirus with such mutations might be associated with the pathogenesis of CNS complications, including meningoencephalitis.

Rotavirus meningoencephalitis in a previously healthy child and a review of the literature

A 31/2-year-old child presented with symptoms of acute gastroenteritis and evidence of central nervous system disease. Evaluation revealed findings consistent with meningoencephalitis and rotavirus detected in the cerebrospinal fluid by polymerase chain reaction. A review of the literature describes 23 cases of central nervous system disease attributed to rotavirus.

Detection, genetic characterization, and quantification of norovirus RNA from sera of children with gastroenteritis

BACKGROUND

Norovirus (NoV) infection is thought to be confined to the intestines, whereas many reports suggest antigenemia and viremia occur during rotavirus gastroenteritis.

OBJECTIVES

To detect NoV RNA in sera and cerebrospinal fluids (CSF) from NoV-infected children, and to quantify and genetically characterize the NoV found in these compartments.

STUDY DESIGN

Semi-nested PCR was conducted on stool, serum and CSF samples from 56 patients with acute gastroenteritis. Positive samples for NoV were analyzed further by sequencing and real-time PCR.

RESULTS

From 39 patients with NoV RNA in stools, 6 also had NoV RNA in sera and none had NoV RNA in CSF. Genotypes of the NoV in stool and serum from the same patient matched completely. The strains in this study had high homology (98.1-100%) with registered strains in the database. The median viral load in stools of the serum-positive patients was greater than that of the serum-negative patients, but this difference was not statistically significant (9.8 x 10(9)copies/g versus 1.1 x 10(9)copies/g (p=0.117)).

CONCLUSIONS

NoV RNA appeared in the blood stream in 15% of the patients of NoV gastroenteritis. Although the viral load in stool was not statistically correlated with NoV appearance in serum, genetic analysis indicated that NoV RNA in sera originated from the NoV gastroenteritis.

High frequency of rotavirus viremia in children with acute gastroenteritis: discordance of strains detected in stool and sera

Recently, rotavirus antigenemia and viremia have been identified in patients with acute gastroenteritis. This study examined rotavirus viremia in children hospitalized for acute gastroenteritis in order to establish its association with fecal shedding of rotavirus, infecting genotypes and antibody marker of acute infection. Thirty-one pairs of stool-serum specimens were collected from November 2004 to February 2005 together with clinical information. All paired specimens were screened for rotavirus RNA by RT-PCR using the VP6 gene primers. All stool and serum specimens were tested for rotavirus antigen and anti-rotavirus IgM respectively by ELISA. Sixteen of 31 stool-serum pairs showed the presence of rotavirus RNA. Nine stool and two serum specimens were positive only by RT-PCR. The total positivity in rotavirus RNA was significantly higher in both stools (80.6%) and sera (58.1%) than that of stool antigen (38.7%) and anti-rotavirus IgM (25.8%) (P < 0.01). All PCR positive paired specimens were typed for the VP7 (G) and VP4 (P) genes. Five of sixteen pairs could be typed for both genes. Three of the five pairs showed concordance (G2P[4]/G2P[4]) while two showed discordance (G12P[8]/G2P[4], G8P[4]/G2P[4]) in the genotypes detected in stool and serum specimens respectively. The study documents a high frequency of rotavirus viremia in patients with acute diarrhea. The discordance of rotavirus strains at the genotypic level in the serum and stool of individual patients with diarrhea suggests the susceptibility of extra-intestinal sites for rotavirus infection and the possibility of differential dissemination of rotavirus strains from the intestine.

Rotavirus-induced seizures in childhood

Rotavirus infection is a frequent cause of gastroenteritis in children and accounts for significant morbidity and mortality, especially in the developing world. Less well recognized is the association of rotavirus-induced central nervous system dysfunction, which has been associated with seizure, encephalopathy, and death. Symptoms may vary widely, however, and children can experience short afebrile convulsions as the only manifestation of rotavirus encephalopathy. We report 4 further cases of rotavirus-induced seizures with mild neurologic manifestations. The condition is reviewed and practical management strategies are suggested.

Rotavirus infection of infant and young adult nonobese diabetic mice involves extraintestinal spread and delays diabetes onset

Rotaviruses have been implicated as a possible viral trigger for exacerbations in islet autoimmunity, suggesting they might modulate type 1 diabetes development. In this study, the ability of rotavirus strain RRV to infect the pancreas and affect insulitis and diabetes was examined in nonobese diabetic (NOD) mice, an experimental model of type 1 diabetes. Mice were inoculated either orally or intraperitoneally as infants or young adults. In infant mice inoculated orally, rotavirus antigen was detected in pancreatic macrophages outside islets and infectious virus was found in blood cells, pancreas, spleen, and liver. Extraintestinal RRV spread and pancreatic presence of infectious virus also occurred in intraperitoneally inoculated infant and adult mice. The initiation of insulitis was unaltered by infection. The onset of diabetes was delayed in infant mice inoculated orally and infant and adult mice inoculated intraperitoneally. In contrast, adult mice inoculated orally showed no evidence of pancreatic RRV, the lowest rate of detectable RRV replication, and no diabetes modulation. Thus, the ability of RRV infection to modulate diabetes development in infant and young adult NOD mice was related to the overall extent of detectable virus replication and the presence of infectious virus extraintestinally, including in the pancreas. These studies show that RRV infection of infant and young adult NOD mice provides significant protection against diabetes. As these findings do not support the hypothesis that rotavirus triggers autoimmunity related to type 1 diabetes, further research is needed to resolve this issue.

Rotavirus antigenemia in children is associated with viremia

BACKGROUND

Antigenemia is commonly detected in rotavirus-infected children. Although rotavirus RNA has been detected in serum, definitive proof of rotavirus viremia has not been shown. We aimed to analyze a defined patient population to determine if infectious virus could be detected in sera from children with rotavirus antigenemia.

METHODS AND FINDINGS

Serum samples obtained upon hospitalization from children with gastroenteritis (57 stool rotavirus-positive and 41 rotavirus-negative), children with diagnosed bronchiolitis of known (n = 58) or unknown (n = 17) viral etiology, children with noninfectious, nonchronic conditions (n = 17), and healthy adults (n = 28) were tested for rotavirus antigen by enzyme immunoassay (EIA). Results of serum antigen testing were assessed for association with clinical and immunological attributes of the children. Rotavirus antigenemia was detected in 90% (51/57) of children with rotavirus-positive stools, in 89% (8/9) of children without diarrhea but with rotavirus-positive stools, in 12% (2/17) of children with bronchiolitis of unknown etiology without gastroenteritis, and in 12% (5/41) of children with gastroenteritis but with rotavirus-negative stools. Antigenemia was not detected in sera from children with noninfectious nonchronic conditions, children with bronchiolitis of known etiology and no gastroenteritis, or healthy adults. Neither age nor timing of serum collection within eight days after onset of gastroenteritis significantly affected levels of antigenemia, and there was no correlation between antigenemia and viral genotype. However, there was a negative correlation between serum rotavirus antigen and acute rotavirus-specific serum IgA (r = -0.44, p = 0.025) and IgG (r = -0.40, p = 0.01) titers. We examined 11 antigen-positive and nine antigen-negative sera for infectious virus after three blind serial passages in HT-29 cells using immunofluorescence staining for rotavirus structural and nonstructural proteins. Infectious virus was detected in 11/11 (100%) sera from serum antigen-positive children and in two out of nine (22%) sera samples from antigen-negative children (p = 0.002).

CONCLUSIONS

Most children infected with rotavirus are viremic. The presence of viremia is directly related to the detection of antigenemia and is independent of the presence of diarrhea. Antigenemia load is inversely related to the titer of antirotavirus antibody in the serum. The finding of infectious rotavirus in the blood suggests extraintestinal involvement in rotavirus pathogenesis; however, the impact of rotavirus viremia on clinical manifestations of infection is unknown.

Gastroenteric Viruses

In recent years, viruses have been recognized increasingly as an important cause of foodborne infections. More than 160 enteric viruses are excreted in the feces of infected individuals, and some may also be present in the vomitus. Food and water are directly contaminated with fecal material, through the use of sewage sludge in agriculture, sewage pollution of shellfish culture beds, or may be contaminated by infected food-handlers.

Prevention of rotavirus disease: guidelines for use of rotavirus vaccine

On February 3, 2006, a bovine-based pentavalent rotavirus vaccine (RotaTeq, Merck & Co Inc, Whitehouse Station, NJ) was licensed by the US Food and Drug Administration for use in infants in the United States. The American Academy of Pediatrics recommends routine immunization of infants with 3 doses of pentavalent rotavirus vaccine administered orally at 2, 4, and 6 months of age. The first dose should be administered between 6 and 12 weeks of age; immunization should not be initiated for infants older than 12 weeks of age. Subsequent doses should be administered at 4- to 10-week intervals, and all 3 doses of vaccine should be administered by 32 weeks of age. Pentavalent rotavirus vaccine can be coadministered with other childhood vaccines. Pentavalent rotavirus vaccine is contraindicated for infants with a serious allergic reaction to any vaccine component or to a previous dose of vaccine.

Rotavirus proteins: structure and assembly

Rotavirus is a major pathogen of infantile gastroenteritis. It is a large and complex virus with a multilayered capsid organization that integrates the determinants of host specificity, cell entry, and the enzymatic functions necessary for endogenous transcription of the genome that consists of 11 dsRNA segments. These segments encode six structural and six nonstructural proteins. In the last few years, there has been substantial progress in our understanding of both the structural and functional aspects of a variety of molecular processes involved in the replication of this virus. Studies leading to this progress using of a variety of structural and biochemical techniques including the recent application of RNA interference technology have uncovered several unique and intriguing features related to viral morphogenesis. This review focuses on our current understanding of the structural basis of the molecular processes that govern the replication of rotavirus.

Active viremia in rotavirus-infected mice

Rotavirus circulates extraintestinally in animals used as models for rotavirus infection and in children. Rotavirus infection in mice was used to define host or viral factors that affect rotavirus viremia. Antigenemia was observed with homologous and heterologous rotaviruses, and neither age nor mouse strain genetics altered the occurrence of rotavirus antigenemia or viremia. Rotavirus RNA and infectious virus were present in sera and associated with the plasma fraction of blood in all infected mice. These findings indicate that antigenemia/viremia occurs routinely in rotavirus infections and imply that infectious rotavirus has access to any extraintestinal cell within contact of blood.

Rotaviruses interact with alpha4beta7 and alpha4beta1 integrins by binding the same integrin domains as natural ligands

Group A rotaviruses are major intestinal pathogens that express potential alpha4beta1 and alpha4beta7 integrin ligand sequences Leu-Asp-Val and Leu-Asp-Ile in their outer capsid protein VP7, and Ile-Asp-Ala in their spike protein VP4. Monkey rotavirus SA11 can use recombinant alpha4beta1 as a cellular receptor. In this study a new potential alpha4beta1, alpha4beta7 and alpha9beta1 integrin ligand sequence, Tyr-Gly-Leu, was identified in VP4. It was shown that several human and monkey rotaviruses bound alpha4beta1 and alpha4beta7, but not alpha9beta1. Binding to alpha4beta1 mediated the infectivity and growth of monkey rotaviruses, and binding to alpha4beta7 mediated their infectivity. A porcine rotavirus interacted with alpha4 integrins at a post-binding stage to facilitate infection. Activation of alpha4beta1 increased rotavirus infectivity. Cellular treatment with peptides containing the alpha4 integrin ligand sequences Tyr-Gly-Leu and Ile-Asp-Ala eliminated virus binding to alpha4 integrins and infectivity. In contrast, rotavirus recognition of alpha4 integrins was unaffected by a peptide containing the sequence Leu-Asp-Val or by a mutation in the VP7 Leu-Asp-Val sequence. VP4 involvement in rotavirus recognition of alpha4beta1 was demonstrated with rotavirus reassortants. Swapping and point mutagenesis of alpha4 surface loops showed that rotaviruses required the same alpha4 residues and domains for binding as the natural alpha4 integrin ligands: mucosal addressin cell adhesion molecule-1, fibronectin and vascular cell adhesion molecule-1. Several rotaviruses are able to use alpha4beta7 and alpha4beta1 for cell binding or entry, through the recognition of the same alpha4-subunit domains as natural alpha4 ligands.

Rotavirus enterotoxin NSP4 binds to the extracellular matrix proteins laminin-beta3 and fibronectin

Rotavirus is the most important cause of viral gastroenteritis and dehydrating diarrhea in young children. Rotavirus nonstructural protein 4 (NSP4) is an enterotoxin that was identified as an important agent in symptomatic rotavirus infection. To identify cellular proteins that interact with NSP4, a two-hybrid technique with Saccharomyces cerevisiae was used. NSP4 cDNA, derived from the human rotavirus strain Wa, was cloned into the yeast shuttle vector pGBKT7. An intestinal cDNA library derived from Caco-2 cells cloned into the yeast shuttle vector pGAD10 was screened for proteins that interact with NSP4. Protein interactions were confirmed in vivo by coimmunoprecipitation and immunohistochemical colocalization. After two-hybrid library screening, we repeatedly isolated cDNAs encoding the extracellular matrix (ECM) protein laminin-beta3 (amino acids [aa] 274 to 878) and a cDNA encoding the ECM protein fibronectin (aa 1755 to 1884). Using deletion mutants of NSP4, we mapped the region of interaction with the ECM proteins between aa 87 and 145. Deletion analysis of laminin-beta3 indicated that the region comprising aa 726 to 875 of laminin-beta3 interacts with NSP4. Interaction of NSP4 with either laminin-beta3 or fibronectin was confirmed by coimmunoprecipitation. NSP4 was present in infected enterocytes and in the basement membrane (BM) of infected neonatal mice and colocalized with laminin-beta3, indicating a physiological interaction. In conclusion, two-hybrid screening with NSP4 yielded two potential target proteins, laminin-beta3 and fibronectin, interacting with the enterotoxin NSP4. The release of NSP4 from the basal side of infected epithelial cells and the subsequent binding to ECM proteins localized at the BM may signify a new mechanism by which rotavirus disease is established.

Comparison of storage methods for reverse-transcriptase PCR amplification of rotavirus RNA from gorilla (Gorilla g. gorilla) fecal samples

Detection of enteric viral nucleic acids in preserved gorilla fecal specimens was investigated using reverse transcription polymerase chain reaction (rt-PCR). A commercially available viral RNA extraction kit was used to isolate nucleic acids from captive gorilla fecal samples seeded with rotavirus and stored in ethanol, formalin, a commercial RNA preservation solution, guanidine thiocyanate buffer (GT), and samples dried in tubes containing silica gel. Nucleic acids were extracted at 1, 7, 70 and 180 days and used for rt-PCR amplification of specific rotavirus RNA sequences. Successful rt-PCR amplification of the target product varied according to storage conditions, and storage time. Only samples stored in GT gave 100% positive results at 180 days. It is recommended that fecal samples be collected in GT for viral RNA analysis.

A lymphatic mechanism of rotavirus extraintestinal spread in the neonatal mouse

We used the neonatal mouse model of rotavirus infection and virus strains SA11-clone 4 (SA11-Cl4) and Rhesus rotavirus (RRV) to examine the mechanism of the extraintestinal spread of viruses following oral inoculation. The spread-competent viruses, RRV and reassortant R7, demonstrated a temporal progression from the intestine, to the terminal ileum, to the mesenteric lymph nodes (MLN), and to the peripheral tissues. SA11-Cl4 was not found outside the intestine. Reassortant virus S7, which was unable to reach the liver in previous studies (E. C. Mossel and R. F. Ramig, J. Virol. 76:6502-6509, 2002), was recovered from 60% of the MLN, suggesting that there are multiple determinants for the spread of virus from the intestine to the MLN. Phenotypic segregation analysis identified RRV genome segment 6 (VP6) as a secondary determinant of the spread of virus to the MLN (P = 0.02) in reassortant viruses containing segment 7 from the spread-incompetent parent. These data suggest that in the orally infected neonatal mouse, the extraintestinal spread of rotavirus occurs via a lymphatic pathway, and the spread phenotype is primarily determined by NSP3 and can be modified by VP6.

Rotavirus antigenaemia and viraemia: a common event?

BACKGROUND

Rotavirus infection is thought to be confined to the intestine. Reports of rotavirus RNA in the cerebral spinal fluid and serum of children infected with rotavirus suggest the possibility that rotavirus escapes the intestine into the circulatory system. We assessed whether rotavirus antigen, RNA, or both, were present in serum samples from immunocompetent rotavirus-infected children and animals.

METHODS

We obtained sera from immunocompetent mice, rats, rabbits, and calves 1-10 days after inoculation with rotavirus or matched vehicle. We obtained sera retrospectively from immunocompetent children diagnosed with rotavirus diarrhoea (n=33), healthy children (n=6) and adults (n=12), children convalescing from rotavirus (n=6), and children with non-rotavirus diarrhoea (n=11). Samples were analysed for the presence of rotavirus antigen or RNA by EIA or RT-PCR, respectively.

FINDINGS

Rotavirus antigen was present in sera from rotavirus-infected animals, but not in sera from control animals. Infectious rotavirus or rotavirus RNA was detected in sera of mice and calves, respectively. Antigen was present in 22 of 33 serum samples from children with confirmed rotavirus infection but in none of 35 samples from controls. Detection of serum antigen was inversely related to the number of days between symptom onset and sample collection, and directly related to stool antigen concentration. Rotavirus RNA was detected by RT-PCR in three of six rotavirus-positive sera.

INTERPRETATION

Rotavirus can escape the gastrointestinal tract in children, resulting in antigenaemia and possible viraemia. This finding is important for the understanding of the pathogenesis, immunology, and clinical manifestations of rotavirus infection.