Detection of rotavirus RNA in cerebrospinal fluid in a case of rotavirus gastroenteritis with febrile seizures

Understanding the Central Nervous System Symptoms of Rotavirus: A Qualitative Review

This qualitative review on rotavirus infection and its complications in the central nervous system (CNS) aims to understand the gut–brain mechanisms that give rise to CNS driven symptoms such as vomiting, fever, feelings of sickness, convulsions, encephalitis, and encephalopathy. There is substantial evidence to indicate the involvement of the gut–brain axis in symptoms such as vomiting and diarrhea. The underlying mechanisms are, however, not rotavirus specific, they represent evolutionarily conserved survival mechanisms for protection against pathogen entry and invasion. The reviewed studies show that rotavirus can exert effects on the CNS trough nervous gut–brain communication, via the release of mediators, such as the rotavirus enterotoxin NSP4, which stimulates neighboring enterochromaffin cells in the intestine to release serotonin and activate both enteric neurons and vagal afferents to the brain. Another route to CNS effects is presented through systemic spread via lymphatic pathways, and there are indications that rotavirus RNA can, in some cases where the blood brain barrier is weakened, enter the brain and have direct CNS effects. CNS effects can also be induced indirectly as a consequence of systemic elevation of toxins, cytokines, and/or other messenger molecules. Nevertheless, there is still no definitive or consistent evidence for the underlying mechanisms of rotavirus-induced CNS complications and more in-depth studies are required in the future.

Molecular characterization of rotaviruses obtained from patients with rotavirus-associated encephalitis/encephalopathy

Group A rotavirus (RVA) rarely causes severe complications such as encephalitis/encephalopathy. However, the pathophysiology of this specific complication remains unclear. Next-generation sequence analysis was used to compare the entire genome sequences of RVAs detected in patients with encephalitis/encephalopathy and gastroenteritis. This study enrolled eight patients with RVA encephalitis/encephalopathy and 10 with RVA gastroenteritis who were treated between February 2013 and July 2014. Viral RNAs were extracted from patients' stool, and whole-genome sequencing analysis was carried out to identify the specific gene mutations in RVA obtained from patients with severe neurological complications. Among the eight encephalitis/encephalopathy cases, six strains were DS-1-like G1P[8] and the remaining two were Wa-like G1P[8] (G1-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1). Meanwhile, eight of the 10 viruses detected in rotavirus gastroenteritis patients were DS-1-like G1P[8], and the remaining two were Wa-like G1P[8]. These strains were further characterized by conducting phylogenetic analysis. No specific clustering was demonstrated in RVAs detected from encephalitis/encephalopathy patients. Although the DS-1-like G1P[8] strain was predominant in both groups, no specific molecular characteristics were detected in RVAs from patients with severe central nervous system complications.

Systemic Manifestation of Rotavirus Infection in Children: A Report of Three Cases

Introduction

Rotavirus is a leading cause of acute gastroenteritis in children. Although the clinical complaints associated with rotavirus are generally gastrointestinal, including vomiting and diarrhea, data suggest that it can also cause symptoms that extend beyond the gastrointestinal tract.

Case Presentations

We report three pediatric cases of rotavirus infection: one accompanied by encephalopathy and two with elevated hepatic transaminase activity. The patients were admitted to Dr. Sami Ulus maternity and children’s health and diseases training and research hospital, Ankara, Turkey, from 2012 - 2014. The presented patients’ aspartate aminotransferase (AST) (1765-2614 IU L^-1) and alanine aminotransferase (ALT) (1448-3558 IU L^-1) levels are, to date, the highest reported levels associated with rotavirus infections, and suggest that the rotavirus can cause severe hepatic transaminase elevation.

Conclusions

This report aimed to increase awareness of the occurrence of extra-intestinal systemic manifestations of rotavirus infection. Although such cases may be rare, they still suggest that that rotavirus is a systemic viral infection.

Systemic features of rotavirus infection

A growing body of evidence warrants a revision of the received/conventional wisdom of rotavirus infection as synonymous with acute gastroenteritis. Rotavirus vaccines have boosted our interest and knowledge of this virus, but also importantly, they may have changed the landscape of the disease. Extraintestinal spread of rotavirus is well documented, and the clinical spectrum of the disease is widening. Furthermore, the positive impact of current rotavirus vaccines in reducing seizure hospitalization rates should prompt a reassessment of the actual burden of extraintestinal manifestations of rotavirus diseases. This article discusses current knowledge of the systemic extraintestinal manifestations of rotavirus infection and their underlying mechanisms, and aims to pave the way for future clinical, public health and research questions.

Decreased mean platelet volume in children with acute rotavirus gastroenteritis

BACKGROUND

The contribution of platelets to the inflammatory response via several platelet derived mediators is well recognized. The role of mean platelet volume (MPV) in infectious and inflammatory disorders, however, has not yet been well-established. While some of the previous studies demonstrated that MPV acted as a positive acute phase reactant, several others suggested its role as a negative acute phase reactant. In the current study, we aimed to assess the role of MPV as an acute phase reactant in children with rotavirus gastroenteritis.

METHODS

We undertook a prospective, randomized, controlled, cross-sectional study and enrolled children diagnosed with acute rotavirus gastroenteritis and healthy controls (HC), between August and November 2012. Children with acute gastroenteritis were assigned either in the rotavirus-positive acute gastroenteritis (RPAG) or in the rotavirus-negative acute gastroenteritis (RNAG) group depending on their stool antigen results. Patients were also classified into two groups based on their Vesikari score (< 11: non-severe and ≥ 11: severe). Complete blood count and C-reactive protein (CRP) levels were assessed for all patients. We compared MPV between RPAG, RNAG and HC groups and investigated the association, if any, among MPV, platelets, white blood count and CRP.

RESULTS

In total 100 RPAG (54 males; mean age: 38.74 ± 41.45 months), 100 RNAG (58 males; mean age: 32.84 ± 29.64 months) children and 100 HC (43 males; mean age: 33.21 ± 32.55 months) were enrolled into the study. Mean platelet counts were well-matched among groups (p > 0.05). We observed a steady decline in MPV (fL) in the HC, RPAG and RNAG groups (median 7.80, 7.35 and 7.30, respectively; p < 0.0001). We did not find an association between MPV and the clinical score of gastroenteritis (p > 0.05).

CONCLUSION

We found that MPV could be used as an acute phase reactant in children with rotavirus gastroenteritis. We believe that the current study will contribute to our understanding of MPV as an inflammatory marker.

Serum transaminase elevation in children with rotavirus gastroenteritis: seven years' experience

BACKGROUND

There are no studies on clinically significant transaminase elevation due to rotavirus gastroenteritis in the literature. Also, there are significant discrepancies among previous studies regarding the prevalence of increased serum transaminase levels in rotavirus infection.

METHODS

Patients investigated for rotavirus by stool antigen testing, who were followed between January 2005 and May 2012, were retrospectively enrolled in this study. Patients were divided into 2 groups according to their rotavirus results: rotavirus-positive acute gastroenteritis (RPAG) and rotavirus-negative acute gastroenteritis (RNAG) groups.

RESULTS

A total of 4317 children who presented with acute gastroenteritis were assessed. The study was completed with 642 patients who met the inclusion criteria. In the RPAG group (n = 272), elevated alanine aminotransferase (ALT) was found in 42 (15.4%) patients and elevated aspartate aminotransferase (AST) in 69 (25.4%), while in the RNAG group (n = 370), these numbers were 25 (6.8%) and 44 (11.9%), respectively. The elevated ALT and AST levels were found to be significantly higher in the RPAG group than in the RNAG group (both p < 0.001). The prevalence of elevated transaminase levels was found to be similar with respect to gastroenteritis severity score (p > 0.05). The high serum transaminase levels normalized uneventfully in all patients in the RPAG and RNAG groups during follow-up.

CONCLUSIONS

In this study, our results clearly signify a liver influence in rotavirus infections. Therefore, rotavirus infections should be kept in mind when evaluating the aetiology of transaminase elevation in patients with acute gastroenteritis.

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.

Antigenemia and cytokine expression in rotavirus gastroenteritis in children

BACKGROUND

Antigenemia is commonly found in children with rotavirus infection, although its clinical significance is undetermined. The aim of this study was to evaluate the association of antigenemia with clinical manifestations and cytokine profiles in children infected by rotavirus.

METHODS

In total, 68 children hospitalized with rotavirus gastroenteritis were enrolled. Serum samples were collected for detection of antigenemia and viremia. Clinical, laboratory and demographic data were analyzed. Proinflammatory, Th1 and Th2 cytokines were evaluated by bead-based flow cytometry.

RESULTS

Antigenemia and viremia were found in 45.6% (n = 31) and 5.9% (n = 4) of the 68 rotavirus-infected children, respectively. The mean age of the antigenemia group was significantly greater than that of the non-antigenemia group (43.5 vs. 27.3 months; p = 0.034). The antigenemia group had a significantly shorter length of hospitalization (4.8 vs. 5.8 days; p = 0.0354) in comparison with the non-antigenemia group, and antigenemia was inversely associated with the length of hospitalization (β = 0.31, p = 0.021). A significantly higher tumor necrosis factor (TNF)-β level was found in the patients with antigenemia than those without (236.7 vs. 29.2 pg/mL, p = 0.026). The severity of disease and the rate of extra-intestinal manifestations did not differ between the groups. Viremia was associated with a higher fever (p = 0.012).

CONCLUSIONS

Antigenemia was positively correlated with shorter hospital stay in children with rotavirus infection. Enhanced innate and T-cell-mediated immunity evidenced by up-regulation of TNF-β was found in patients with antigenemia.

Benign convulsions associated with mild gastroenteritis: a multicenter clinical study

PURPOSE

To assess the clinical characteristics and the outcome of benign convulsions associated with mild gastroenteritis (CwG) in Italian children.

METHODS

We studied clinical and EEG features of 128 children with CwG who were hospitalized between January 2004 and February 2008 and then followed for at least 12 months in 14 Italian centers.

RESULTS

Age at onset ranged from 6 to 60 months. The seizures were generalized in 73 cases (57%), only focal in 16 (12.5%), and secondarily generalized in 39 (30.5%). The duration of the seizures was under 5 min in 97 patients (75.8%), between 5 and 30 min in 26 (20.3%), and longer than 30 min in 5 (3.9%). Seventy-three participants (57%) had 2 or more seizures, which recurred within 24-48 h. In the acute phase, antiepileptic drugs were used in 72 patients (56.3%). Although interictal abnormalities were present in EEG of 28 children (21.9%), these reverted to normal. During the follow up period, only 6 patients (4.7%) suffered from recurrence of CwG, 7 (5.5%) suffered from simple febrile seizures, and 3 (2.3%) developed epilepsy.

CONCLUSIONS

Recognition of CwG in children allows pediatricians to avoid extensive evaluations and continuous antiepileptic therapy and to reassure parents regarding the lack of long-term complications.

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.

FIRST: a practical approach to the causes and management of febrile seizures

During almost 4 decades of clinical practice of pediatrics and pediatric neurology, the senior authors have rarely made a formal presentation on the topic of "febrile seizures." In any large pediatric teaching hospital, questions regarding the diagnosis and management of febrile seizures are raised by medical students, pediatric residents, and adult and pediatric neurology residents. The acronym FIRST was developed as a teaching tool to present a simple and pragmatic clinical approach to children presenting with a single seizure or cluster of seizures in 1 day associated with a febrile illness before, during, or after the seizure event(s). FIRST refers to Febrile, Illness, Related, Seizure(s) and Template, with the latter representing an outline of the basic cause(s). The authors propose the use of the Table as a tool to help determine the underlying etiology of febrile seizures because this is the major factor affecting the choice of treatment.

Enhancement of detection and quantification of rotavirus in stool using a modified real-time RT-PCR assay

A sensitive and specific real-time RT-PCR assay to detect rotavirus in stool samples was optimized and validated using a wide range of rotavirus genotypes. The target of the original TaqMan(R) assay is an 87 bp fragment of the highly conserved non-structural protein 3 (NSP3) gene. Here we modified the original assay by introducing degeneracy into the forward primer to account for sequence variation between rotavirus genotypes, added four nucleotides at the 3' end of the reverse primer to reduce its stability, and modified the probe label. Amplification and detection conditions were optimized using purified dsRNA from two cultivated strains. The limit of detection of the modified assay was calculated to be approximately 44 genome copies per reaction. To validate the reactivity of the assay, 103 archived RNAs that had been extracted from stools and genotyped during routine U.S. surveillance were tested. Samples were selected to represent both rare and common genotypes that have been detected in U.S. children. Nine genotypes known to be circulating in the United States were detected by the real-time assay demonstrating broad reactivity. In addition, other enteric viruses were not detected demonstrating that the assay is specific for rotavirus and does not cross-react with other viruses potentially present in stool samples. This real-time assay is an important addition to the arsenal of molecular tools available to quickly identify rotavirus in stool samples during routine surveillance.

Rotavirus gastroenteritis: Why to back up the development of new vaccines?

Rotaviruses (RVs) are the main aetiologic agent of severe acute diarrhoea in children under the age of 5, worldwide. Given that the currently available preventive measures to fight against the transmission of RV disease are not sufficiently effective, vaccination likely represents the only efficacious adapted response to the massive impact of this infection. Although the two current RV vaccines have shown good tolerance and significant efficacy to protect infant against severe RV disease, their development have raised key questions that are still unanswered regarding their cost, efficacy and safety. These two vaccines have in common the disadvantages related to the use of oral attenuated live viruses which limit their implementation in both developed and developing countries. In order to overcome these hurdles, it is important to support the development of new, non-replicating vaccines which will not suffer the potential disadvantages of the present vaccines. New approaches and other routes of administration are being tested in animal models and soon will be evaluated in humans. Among those are viral-like particle-based vaccines which have provided the most promising results. Finally, the epidemiology of the disease which differs in developed and developing countries can affect decisions about vaccine composition and delivery. The answer brought by the development of new RV vaccines could reside in developing several types of RV vaccines specifically designed to be used in different settings.

Rotavirus vaccines: an overview

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. In 1999, a highly efficacious rotavirus vaccine licensed in the United States, RotaShield, was withdrawn from the market after 14 months because of its association with intussusception. Two new live, oral, attenuated rotavirus vaccines were licensed in 2006: the pentavalent bovine-human reassortant vaccine (RotaTeq) and the monovalent human rotavirus vaccine (Rotarix). Both vaccines have demonstrated very good safety and efficacy profiles in large clinical trials in western industrialized countries and in Latin America. Careful surveillance has not revealed any increased risk of intussusception in the vaccinated groups with either vaccine. The new rotavirus vaccines are now introduced for routine use in a number of industrialized and developing countries. These new safe and effective rotavirus vaccines offer the best hope of reducing the toll of acute rotavirus gastroenteritis in both developed and developing countries.

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.

Rotavirus vaccines: current prospects and future challenges

Rotavirus is the most common cause of severe diarrhoea in children worldwide and diarrhoeal deaths in children in developing countries. Accelerated development and introduction of rotavirus vaccines into global immunisation programmes has been a high priority for many international agencies, including WHO and the Global Alliance for Vaccines and Immunizations. Vaccines have been developed that could prevent the enormous morbidity and mortality from rotavirus and their effect should be measurable within 2-3 years. Two live oral rotavirus vaccines have been licensed in many countries; one is derived from an attenuated human strain of rotavirus and the other combines five bovine-human reassortant strains. Each vaccine has proven highly effective in preventing severe rotavirus diarrhoea in children and safe from the possible complication of intussusception. In developed countries, these vaccines could substantially reduce the number and associated costs of child hospitalisations and clinical visits for acute diarrhoea. In developing countries, they could reduce deaths from diarrhoea and improve child survival through programmes for childhood immunisations and diarrhoeal disease control. Although many scientific, programmatic, and financial challenges face the global use of rotavirus vaccines, these vaccines-and new candidates in the pipeline-hold promise to make an immediate and measurable effect to improve child health and survival from this common burden affecting all children.

Rotavirus gastroenteritis

Rotavirus is the single most important cause of severe, dehydrating gastroenteritis in infants and young children worldwide. Rotavirus gastroenteritis is associated with high morbidity in developed countries and significant mortality in developing countries. Virtually all children are infected with rotavirus by 3 years of age. Fecal-oral transmission is the most likely route of virus spread. Group A serotype strains G1 through G4 account for more than 90% of rotavirus gastroenteritis in humans, with G1 being the predominant serotype. The virus preferentially infects the mature small-intestinal enterocytes. Rotavirus gastroenteritis is characterized by fever, vomiting, and diarrhea, with vomiting particularly prominent. Dehydration is a frequent complication because of the severity of the diarrhea and the associated vomiting. Rehydration and maintenance of proper fluid and electrolyte balance remain the mainstay of treatment. Hygienic measures have little effect on the reduction of rotavirus infection rates. The disease can be effectively controlled by universal rotavirus vaccination.

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.

Increased detection of rotavirus using a real time reverse transcription-polymerase chain reaction (RT-PCR) assay in stool specimens from children with diarrhea

Six-hundred and twenty-six stool specimens collected from children with diarrhea over a 12-month period were tested for rotavirus using a real time reverse transcription-polymerase chain reaction (RT-PCR) assay, a conventional nested PCR assay and by electron microscopy (EM). A fragment of 87 bp in a highly-conserved region of non-structural protein 3 (NSP3) in rotavirus genome was amplified by a single-step RT-PCR protocol in a closed-tube system. Rotavirus was detected in 123 samples (20%) with the real time RT-PCR assay, 113 samples (18%) with the nested-PCR assay, and 79 samples (13%) with EM. Using serial diluted nucleic acid extract, we compared the sensitivity of real time RT-PCR with conventional RT-PCR and conventional nested PCR assays. Real time RT-PCR was two to four logs more sensitive than the conventional assays. The reaction time required for the RT-PCR assay is about half the time required for the conventional nested-PCR. The real time RT-PCR assay is both simple and rapid with advantages including enhanced sensitivity and a lower risk for cross-contamination making it a useful tool for the detection of rotavirus in various situations including sporadic gastroenteritis, outbreaks, and environmental investigations. G(1) was the predominant type (89%), followed by G(2) (10%), and G(4) (1%). No rotavirus of G(3), G(8), and G(9) types were found. The peak season for rotavirus infection was January to May in northern Alberta.

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.

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

Rotavirus RNA was detected in the cerebrospinal fluid (CSF) of a child with central nervous system disease symptoms associated with rotavirus gastroenteritis. The rotavirus isolates from the fecal and CSF samples were genotyped as G1P[8]. Sequence analysis of the VP7 and VP4 proteins derived from the fecal and CSF samples were remarkably similar to each other and to G1P[8] rotavirus strains commonly circulating in the community and associated with gastroenteritis.

The pathogenesis of febrile seizures: is there a role for specific infections?

Although fever is regarded as the main trigger in the pathogenesis of febrile seizures (FS), it is not supposed to be the unique causative factor. In FS, there is a strong familial predisposition. This does not exclude infections as a causative factor because subtle genetic polymorphisms have been demonstrated to affect the course of infections. We review the literature on: (1) the role of fever, especially the height of temperature, its cause, and metabolic effects induced by temperature; (2) the role of heredity; (3) the role of cytokines which play a role in the induction of fever; and (4) the role of type of infection, with emphasis on newly identified agents and improved diagnostic techniques. With modern molecular techniques such as PCR, viruses have been detected in the CSF far more often than previously thought, even in the absence of pleocytosis of the CSF. This makes it difficult to distinguish FS from acute encephalitis. FS may be caused by neuroinvasion or intracerebral activation of viruses. Further studies should focus on these options because therapeutic intervention is possible and may prevent late sequelae such as recurrent FS and subsequent epilepsy.

Acute gastroenteritis-related encephalopathy

We studied the incidence of convulsions in 1936 children with acute gastroenteritis. Sixty-eight children had convulsions (3.5%), which were categorized into three groups: (1) bacterial (n = 13; 19%), (2) Rotavirus (n = 30, 44%), and (3) no organism (n = 25; 37%). Only group 2 versus group 3 had a significant association with encephalopathy (P < .002). The relative risk was estimated to determine the risk of encephalopathy: Rotavirus versus no organism isolated (relative risk = 2.308), Rotavirus versus bacterial (relative risk = 1.846), and bacterial versus no organism (relative risk = 1.25). None developed epilepsy. Thus, acute gastroenteritis-related encephalopathy is a benign condition with single or recurrent seizures during an episode of acute gastroenteritis and an excellent prognosis. The underlying mechanism for provoking seizure is unknown. One should be reassured of a good outcome in the majority of children with recurrent episodes of afebrile/febrile seizures during an episode of acute gastroenteritis.

Rotavirus and central nervous system symptoms: cause or contaminant? Case reports and review

Rotavirus is a common cause of severe gastroenteritis in children. In 2 patients with rotavirus gastroenteritis who developed encephalopathy, rotavirus RNA was detected in the cerebrospinal fluid (CSF) by reverse transcription-polymerase chain reaction; in 1 patient, rotavirus RNA was detected on 2 occasions 3 weeks apart. There are increasing reports of cases in which patients who have seizures after an episode of rotavirus diarrhea have evidence of rotavirus in their CSF. A search of 2 large hospital discharge databases suggested that seizures are noted as part of the discharge diagnosis in the records of, at most, <4% of patients with rotavirus diarrhea versus 7% of patients with bacterial diarrhea. Although evidence suggesting that rotavirus is a cause of central nervous system sequelae remains inconclusive, the 2 case reports presented in this study further illustrate a possible association. Further study is required to determine whether detection of rotavirus in CSF represents a true pathogen, CSF contamination that occurs at the time of lumbar puncture or in the laboratory, or carriage of rotavirus RNA in trafficking lymphocytes.

Evaluation of two current generation enzyme immunoassays and an improved isolation-based assay for the rapid detection and isolation of rotavirus from stool

BACKGROUND

Rapid and accurate rotavirus testing is important in decisions involving patient care and management. Quality assurance testing needs to be periodically performed, especially among widely used assays having a direct impact on patient care.

OBJECTIVES

To evaluate the current generation Kallestad Pathfinder Direct antigen Detection system (PTH), and the widely used Rotaclone(R) Rotavirus EIA Diagnostic Kit (RTC), in comparison with an improved cell culture amplification-antigen detection (CCA-Ag) isolation-based assay.

STUDY DESIGN

Two hundred stool specimens (specimen stored at > or =-75 degrees C), which had been previously tested by PTH, were tested by RTC and CCA-Ag. Discordant specimens were retested by PTH, blocking assay, polyacrylamide gel electrophoresis (PAGE), and/or electron microscopy (EM).

RESULTS

Among 200 stool specimens, 197 were in accord by PTH, RTC and CCA-Ag. The sensitivity, specificity, positive and negative predictive values for RTC, PTH and CCA-Ag were, 100, 99, 99, 100, 100, 99, 99, 100; and 98, 100, 100, 98%, respectively. Among five initially discordant specimens, two required a period of 10 days to affect isolation. A non-cultivatable (CCA-Ag negative) but true positive specimen, was identified as rotavirus group A serotype G2 by RT-PCR. Four true positive but discordant specimens were blocking assay negative using one or both EIA kits.

CONCLUSIONS

PTH and RTC are excellent rotavirus detection system. However, PTH is more expensive (ca. $3.50 vs. $2.00 per test), mandates a slightly longer turn-around time (ca. 1 vs. 1.5 h), and necessitates slightly more hands-on manipulative/preparative steps. Blocking assay was not a reliable confirmatory test for the resolution of specimen discordancy. A combination of CCA-Ag, PAGE, EM, and/or perhaps RT-PCR, is recommended as an appropriate test panel for the resolution of discordant results during assay evaluation. The newly modified and simplified 48-h rotavirus isolation-based assay may serve as a base line methodology in laboratory evalaution studies, as a laboratory support methodology during drug/vaccine efficacy trials, or for the testing of sources (e.g., biopsy/autopsy tissues) not approved for assay by commercial rotavirus kits.

Infantile convulsions with mild gastroenteritis

The development of sensitive new molecular genetic techniques has led to the detection of rotavirus in cerebrospinal fluid, stools and throat swabs from patients with gastroenteritis with accompanying clinical symptoms similar to infantile benign convulsions. Small round structured virus (SRSV) has also been found in stools of patients with similar clinical symptoms by a new procedure. However, the mechanism by which these viral infections induce benign convulsions remains to be elucidated. The present paper reviews recent virological and clinical studies of seizures probably caused by gastroenteritis viruses including rotavirus, SRSV and other viruses.

Rotavirus encephalitis mimicking afebrile benign convulsions in infants

A 2-year-old-boy had rotavirus gastroenteritis and demonstrated afebrile partial seizures with secondary generalization. The presence of rotavirus genome and anti-rotavirus IgG was detected in the cerebrospinal fluid. The genotype of VP4 was P8 and that of VP7 was G4. The imaging analysis by computed tomography and single photon emission computed tomography implied encephalitis. The seizures were well controlled by standard antiepileptic therapy, and the child experienced normal development with neither physical nor neurologic sequelae, which appeared to mimic benign infantile partial epilepsy.