Hospital-acquired rotavirus and norovirus acute gastroenteritis in a pediatric unit, in 2014-2015.

The occurrence of hospital-acquired acute gastroenteritis (AGE) is a major concern for public health. RotavirusA (RVA) and norovirus (NoV) are common causes of viral AGE in the pediatric population, and their role in nosocomial infections has been proven, remaining poorly investigated. To investigate RVA and NoV in hospital-acquired AGE, 55 stool samples from children with nosocomial AGE were collected between May 2014 and May 2015. To evaluate virus spreading routes, 51 environmental swabs were collected from staff and patients' rooms. Stools were tested for both RVA and NoV RNA by reverse-transcription-PCR. Nucleotide sequencing and phylogenetic analysis were performed to characterize the viruses. Forty-seven of 55 cases analyzed resulted positive for RVA. The predominant genotype was G4P[8] (18/55) followed by G1P[8] (14/55). Mixed RVA infections were also detected (7/55). Twenty-two samples were positive for NoV, and GII.4 was revealed to be the predominant genotype. Seventeen samples were positive for both RVA and NoV. This study aimed to evaluate the burden of norovirus and rotavirus nosocomial AGE, contributing to identify the environment source of infections and to activate effective strategies for intervention. The reduction in nosocomial AGE cases is an important aspect, considered the worsened disease course in transplant, cancer, and intensive care unit inpatients.

Proportion of sporadic gastroenteritis cases caused by rotavirus, norovirus, adenovirus and bacteria in Japan from January 2000 to December 2003.

Many kinds of virus and bacterium have been identified as pathogens that cause sporadic gastroenteritis (SG). Among the pathogens, rotavirus (RV), norovirus (NV; previously known as Norwalk-like virus), and adenovirus (AdV) types 40/41 have been considered as the prevalent viruses implicated in the aetiology of childhood gastroenteritis. In the present study, we attempted to estimate monthly proportions of SG cases caused by the viral agents (RV, NV, AdV and other viruses (OV)) and bacterial agents in the whole of Japan. The estimation was carried out by using time series data of the incidence of SG and the viral and bacterial agents of SG, which were collected by a nationwide surveillance system in Japan from January 2000 to December 2003. It was confirmed that, in the dominant period of RV and NV, the proportion of RV-associated SG and that of NV-associated SG indicate almost same level with each other: 46-69% during February-May for RV, and 41-75% during October-December for NV.

Major incidents. Norwalk on the wild side.

An outbreak of the Norwalk-like virus at an acute hospital in October affected 147 patients and 200 staff. It was brought under control within two weeks, following the establishment of a team to manage the incident. Some day surgery was cancelled, but no inpatient operations were affected. The public was discouraged from visiting the hospital during the outbreak. Local GPs were co-operative about managing patients with the virus at home. Some doctors came to work with symptoms, despite the trust urging affected staff to stay at home.

Distribution of human virus contamination in shellfish from different growing areas in Greece, Spain, Sweden, and the United Kingdom.

Viral pollution in shellfish has been analyzed simultaneously across a wide range of geographical regions, with emphasis on the concomitant variations in physicochemical characteristics and social features. The methods for sample treatment and for the detection of human enteric viruses were optimized by the participating laboratories. The second part of this study involves the selection of a protocol for virus detection, which was validated by analyzing the distribution and concentration of human viral pathogens under diverse conditions during an 18-month period in four European countries. Shellfish-growing areas from diverse countries in the north and south of Europe were defined and studied, and the microbiological quality of the shellfish was analyzed. Human adenovirus, Norwalk-like virus, and enterovirus were identified as contaminants of shellfish in all the participating countries. Hepatitis A virus was also isolated in all areas except Sweden. The seasonal distribution of viral contamination was also described. Norwalk-like virus appeared to be the only group of viruses that demonstrated seasonal variation, with lower concentrations occurring during warm months. The depuration treatments currently applied were shown to be adequate for reducing Escherichia coli levels but ineffective for the elimination of viral particles. The human adenoviruses detected by PCR correlate with the presence of other human viruses and could be useful as a molecular index of viral contamination in shellfish.

[Evaluation of Norwalk virus detection kit by enzyme immunoassay].

We briefly examined detection kit using the EIA method for Norwalk virus, and compared the results of the tests using the EIA method with those using RT-PCR method. In reproducibility, an amount of variation was observed in data obtained from positive controls and in lower values. The sensitivity obtained from the EIA method was about 300 times lower than that obtained from the RT-PCR method. Results accordance ratio between EIA method and RT-PCR method was 70%. This results discrepancy was presumably caused by a difference of sensitivity and specificity between these two methods. In conclusion, this detection kit using the EIA method is easily manually operated so that this kit can be considered as an effective and simple detection tool for Norwalk virus.

PCR detection of human enteric viruses in bathing areas, waste waters and human stools in Southwestern France.

Detection of human pathogenic viruses by molecular techniques might be suitable for identifying viral pollution in environmental waters and for improving diagnosis in patients. Environmental samples were taken from bathing areas and sewage treatment plants in southwestern France. Small volume samples (50 microL) were tested. Five groups of enteric pathogenic viruses were studied: enteroviruses, Norwalk-like viruses (NLVs), hepatitis A virus, rotaviruses and adenoviruses. Moreover, human samples were tested for NLV. After extraction of viral nucleic acids (Boom's procedure), a nested polymerase chain reaction was conducted before hybridization. Five bathing waters out of 26 were positive for one viral group, without systematic association with bacterial contamination. Eight sewage plant samples out of 13 were positive for at least one viral group. Seven patients out of 45 were NLV-positive. Molecular techniques allow efficient screening of viral contamination in environmental waters and the study of NLV molecular epidemiology.

RT-PCR identification and typing of astroviruses and Norwalk-like viruses in hospitalized patients with gastroenteritis: evidence of nosocomial infections.

BACKGROUND: Astroviruses (HAstVs) and 'Norwalk-like viruses' (NLV) are frequent causes of gastroenteritis worldwide, though no data on the strains in circulation or their prevalence is available for France. OBJECTIVES: We applied molecular methods to detect HAstVs and NLVs by reverse transcription-polymerase chain reaction (RT-PCR) in fecal samples collected during a 2-year period from children and adults hospitalized with gastroenteritis. STUDY DESIGN: All samples negative for rotavirus and adenovirus by latex agglutination which contained small (25-40 nm) viral particles observed by electron microscopy (EM) were examined by RT-PCR. RT-PCR products were sequenced to characterize the HAstV and NLV strains present. RESULTS: A total of 75 samples were analyzed by RT-PCR, of which 15 were positive for HAstV and 24 for NLV. Several distinct strains of serotype 1 HAstV, the predominant serotype, circulated during the period. Nineteen of the 24 NLVs were of the G2 genogroup including Mexico-like (n=10), Bristol-like (n=8), and Hawaii-like viruses (n=1); two were genogroup 1. Overall, seven (47%) of the 15 HAstV infections and nine (37.5%) of the 24 NLV infections appeared to be nosocomially acquired based on the date of admission in hospital and the date of illness. CONCLUSION: This study provides additional evidence of the importance of nosocomial infections caused by NLV and HAstV.

A novel "small round virus" inducing poult enteritis and mortality syndrome and associated immune alterations.

The role of a novel "small round virus" (SRV) isolated from poult enteritis and mortality syndrome (PEMS) cases in inducing PEMS and associated immune alterations was examined in this study. Specific-pathogen-free and conventional poults were orally challenged with SRV and/or turkey coronavirus and monitored for clinical signs. Intestines, thymus, bursa, and spleens were examined for SRV antigen at various days postinoculation (DPI). Peripheral blood lymphocytes (PBLs), thymocytes, and splenic lymphocytes from inoculated poults or lymphocytes isolated from healthy poults after incubation with SRV in vitro were examined for lymphoproliferative potential against concanavalin A (Con A). The incidence of lymphocyte subpopulations in the peripheral blood and thymic lymphocytes of SRV-challenged poults was examined by flow cytometry. The results of these studies showed that the SRV challenge induced diarrhea, growth suppression, and atrophy of thymus and bursa resembling those of PEMS in field and/or experimental infections. The SRV antigen was detected in intestinal tissues soon after infection (i.e., at 2 and 4 DPI), whereas lymphoid tissues such as thymus, bursa, and spleen were positive for SRV antigen starting at 4 DPI until 8 DPI, suggesting virus translocation to lymphoid organs. The responsiveness of PBLs to Con A at 2 DPI was significantly reduced in all virus challenge groups (e.g., 28% and 22% in the SRV-alone group in studies 1 and 2, respectively) below the uninfected group. However, this suppressed response was no longer evident in the SRV group by 7 DPI. The SRV incubation with normal thymocytes and splenocytes in vitro resulted in significantly reduced lymphoproliferative response against Con A (41.2% and 10.49% reductions at 1:50 SRV dilution vs. controls in thymocytes and splenocytes, respectively). Flow cytometry analysis revealed a sudden decline at 2 DPI in the numbers of CD4- CD8+ lymphocyte subset in PBLs of SRV-infected poults. However, by 8 DPI, SRV-challenged poults had relatively higher CD4- CD8+ lymphocytes in PBLs. On the contrary, thymocytes had higher percentages of CD4- CD8+ lymphocytes at 2 and 4 DPI and reached comparable levels at 8 DPI in controls and SRV-infected poults. No differences were observed in CD4+ CD8- lymphocyte numbers in controls vs. SRV-infected poults. The findings of these studies imply that SRV may be a promising primary etiologic agent of PEMS. Furthermore, the SRV infection may compromise the lymphocyte-mediated immune defenses by reducing lymphoproliferation and the CD4- CD8+ (presumably T-cytotoxic cells) lymphocytes during the acute stage of SRV infection.

A diagnostic EIA for detection of the prevalent SRSV strain in United Kingdom outbreaks of gastroenteritis.

Small round structured viruses (SRSVs) are the major cause of outbreaks of gastroenteritis in the UK. Diagnosis is problematic due to insensitive electron microscopy (EM) or technically demanding reverse transcription polymerase chain reaction (RT-PCR) techniques. We have studied outbreaks of non-bacterial gastroenteritis using an EIA based upon recombinant capsid protein from the currently prevalent circulating strain of SRSV (Lordsdale Genotype II) and compared its performance against EM and RT-PCR assays. Faecal specimens sent to the Bristol Public Health Laboratory for outbreak investigation from December 1996 to December 1997 were applied retrospectively to the SRSV EIA and results compared with the routine EM and RT-PCR that had been carried out prospectively. Overall, the three tests identified SRSVs in specimens from 70% of the outbreaks (213/305) investigated. Of the 213 total positive outbreaks, the EIA identified 71%, that compared favourably with EM (63%) and RT-PCR (84%). The Lordsdale Genotype II SRSV EIA provides a simple cost-effective assay that will for the first time make detection of currently circulating SRSV strains associated with UK outbreaks available to all routine laboratories. The EIA format makes the assay widely applicable to non-specialist laboratories, unlike the RT-PCR assay, and the improved sensitivity over EM will allow successful screening of UK outbreaks alongside commercial EIAs currently available for adenovirus, astrovirus and rotavirus. Furthermore, the assay will allow rapid identification of emerging SRSV strains.

[Surveillance of group illnesses with Norwalk-like viruses (NLV) in Baden-Württemberg. Isolation and detection of Norwalk-like viral RNA from fecal samples with RT-PCR]. / Verfolgung von Gruppenerkrankungen mit Norwalk-like-Viren (NLV) in Baden-Württemberg. Isolierung und Detektion von Norwalk-like-Virus-RNA aus Stuhlproben mittels RT-PCR.

Between the turn of the years 98/99 and 99/2000, stool samples from various health departments in the south of Germany were sent to the LGA (Landesgesundheitsamt Baden-Württemberg). Different testings as bacteriological routines for enterobacteriaceae and virological antigen screenings of the stool samples for adeno-, astro- and rotaviruses lead to negative results. Additional RT-PCR tests for the presence of Norwalk-RNA showed nearly 40% of positive samples. From 14 group infections between december 98 and january 2000, 286 samples in total were sent to the LGA, 118 of them gave positive results for the norwalk agent. For the verification of the analysis, some random samples were sent to the Robert-Koch-Institut, div. of molecular virology at Berlin, where the results were confirmed.

Variation in ORF3 of genogroup 2 Norwalk-like viruses.

The nucleotide sequences of the 3'-terminal open reading frame (ORF3) and 3' untranslated region (3'UTR) were determined for four Norwalk-like viruses (NLVs) belonging to genogroup 2. Three of the viruses, isolated in 1995 and 1996, were closely related to Mexico virus (92-93% nucleotide identity in ORF3). The fourth virus, isolated in 1984, was unique, showing only 49-58% nucleotide identity with other NLVs. The variation in sequence of the 3'-terminal ORF of NLVs was greater than that observed for other caliciviruses. This variation was partly due to repeated sequences and frameshifting. To investigate the properties of the ORF3 encoded polypeptide, a signal sequence and N-linked glycosylation sites predicted for Camberwell virus were tested for function by in vitro translation in the presence of microsomes. Membrane insertion, cleavage of an N-terminal signal sequence, or glycosylation were not detected.

[Detection of HAV, SRSV and astrovirus genomes from native oysters in Chiba City, Japan].

SRSV, astrovirus in tvirus and HAV genomes were detected by RT-PCR in naturally grown oysters (total 112) collected in Chiba City bay, Japan, through a year from April, 1997 to March, 1998 and genogroup was typed by sequencing. SRSV positive products were detected by RT-PCR from 28 out of 112 oysters and all of them were grouped into G-II by sequencing. The highest incidence was observed in February, 1998. Furthermore, astrovirus positive products were detected sporadically from 15 out of 112 samples and the highest incidence was observed in January, 1998. On the other hand, HAV was detected from only 2 out of 112 and no adenovirus positive product was detected. The results indicated that both SRSV and astrovirus were predominantly distributed into naturally grown oysters in the winter season. SRSV and astrovirus seem to contribute mainly to the food-born outbreaks of gastroenteritis occurred by eating contaminated oysters as causative agents.

Detección de virus Norwalk y México, dos calicivirus humanos en deposiciones de niños chilenos / Detection of Norwalk and Mexico virus, 2 human calciviruses in feces of chilean children

Background: Human calciviruses (HuCVs) cause diarrhea outbreaks associated with consumption of contaminated food and water. Seroepidemiological studies in developing countries, suggest that HuCVs can cause acute gastroenteritis in children. Aim: To study the presence of Norwalk (NV) and Mexico (MX) virus, two HuCVs, in stools of Chilean children from different settings. Subjects and methods: ELISA tests for NV and MX were performed in 677 stool samples for children aged 0 to 132 years old, with acute diarrhea occurring in day care centers or consulting in outpatient clinics or emergency rooms. We also studied eight samples from children involved in a diarrhea outbreak that occurred in a rural community in 1992. A subset of samples was tested with polymerase chain reactions using different primers. Results: Only one sample from a child with acute diarrhea occurring in a day care center was positive for HuCV by polymerase chain reaction. Three samples from the outbreak were positive by the latter method and by ELISA. The HuCV obtained from the day care center was genetically different from other known HuCV. Conclusions: Despite the high seroprevalence, NV and MX viruses were detected in a very low proportion of Chilean children stools

Evolución temporal del patrón de aislamiento de enteropatógenos en diarrea aguda / Temporal evolution of pattern's isolation of enteropathogens in acute diarrhoea

Se revisan los datos existentes en el Hospital Infantil de México "Federico Gómez" en relación con los agentes bacterianos causantes de diarreas agudas de pacientes que acuden al Servicio de Hidratación Oral, considerando los más importantes: Shigella, Salmonella, Escherichia coli enteropatógena y Campylobacter. Se comparan estos datos con los que fueron obtenidos entre 1993 y 1997 en el mismo servicio hospitalario. Se estudia la relación de Shigella flexneri con S. sonnei constatando el creciente predominio de S. sonnei. Se reporta la resistencia a antibióticos (ampicilina y bactrim) de Shigella desde 1960, comparando estos hallazgos con los resultados obtenidos en los últimos años. El aumento de cepas resistentes es evidente

Prevalence of enteric viruses in human immunodeficiency virus seropositive patients in Venezuela.

The prevalence of enteric viruses associated with gastroenteritis was determined in 125 stool samples from patients infected with the human immunodeficiency virus (HIV), with or without diarrhea. Diagnostic assays included enzyme immunoassays for the identification of rotavirus, adenovirus, and Norwalk virus; polyacrylamide gel electrophoresis for atypical rotaviruses and picobirnaviruses and polymerase chain reaction for astrovirus. Enteric viruses were detected in 6.4% (8 of 125) of the stools collected: five (4.0%) samples positive for adenoviruses, and three (2.3%) samples positive for picobirnaviruses were detected. No rotavirus, astrovirus, or Norwalk virus were observed. Only one of the viruses identified (adenovirus) was found in a sample from a patient with diarrhea. Viruses were detected in 10% of the patients with AIDS, 14% of the symptomatic patients, and none of the asymptomatic persons. These results do not support a major role for enteric viruses in the diarrhea suffered by HIV-infected patients.

Norwalk virus infection in Venezuela.

The presence of antibodies against Norwalk virus (NV) was studied in sera from different Venezuelan populations, using an enzyme immuno-assay (EIA) based on recombinant NV protein. Antibodies to NV were found in 47%-53% of urban subjects from Caracas, 83% of rural subjects from the west of the country, and 73%-93% of Amerindian subjects. The prevalences found in the rural and Amerindian groups were significantly higher than that in the urban group. Although about 50% of the children studied were seropositive for NV by the age of 5 years, only four (0.4%) of 1120 faecal samples from children with diarrhoea which were tested for the presence of NV antigen by sandwich EIA were found positive. An increase of at least 4-fold in the titre of anti-NV IgA was found in three (5%) of 61 pairs of sera taken during and 1 month after an acute episode of diarrhoea not due to rotavirus. NV was therefore not a predominant aetiological cause of gastro-enteritis in young children in Venezuela between 1993 and 1995, although it can be the cause of diarrhoea in infants.

Contaminación de los alimentos por virus: un problema de salud pública poco comprendido / Viral contamination of food products: a poorly understood public health problem

En todas partes del mundo han surgido epidemias de enfermedades transmitidas por los alimentos (ETA) sobre las que no existe suficiente información para guiar las acciones de las instituciones de salud pública. El presente estudio se hizo con objeto de contribuir a la diseminación de información sobre esas enfermedades, sus agentes etiológicos y su epidemiología y control. Se utilizaron datos de 61 estudios, entre ellos revisiones, descripciones de brotes y sistematización de datos. De los resultados obtenidos se pudo concluir que hay un gran problema de subregistro y falta de datos sobre estas enfermedades en los diversos países, pero los virus constituyen la segunda causa más importante de ETA en los Estados Unidos de América. Dos agentes, el virus Norwalk y el de la hepatitis A, ocuparon el quinto y sexto lugares, respectivamente, entre las causas principales de ETA, aunque el primero ocupó el primer puesto en 1982 y el segundo lugar como causa principal de enfermedades de transmisión hídrica durante el período de 1986 a 1988. A pesar de la escasez de datos al respecto, los rotavirus, poliovirus, virus de la hepatitis E, astrovirus y pequeños virus gastroentéricos también tienen importancia como agentes de ETA. En el artículo se discute también la importancia de las zoonosis víricas, especialmente de las fiebres hemorrágicas transmitidas por excretas de roedores y las encefalitis víricas transmitidas por garrapatas (fiebre difásica de la leche). Asimismo se presenta la polémica sobre la enfermedad de las vacas locas y su posible transmisión por los alimentos, además de los cuidados alimentarios relacionados con el sida y otras infecciones víricas. Por último, se describen los procedimientos de prevención y control de las ETA víricas

Throughout the world there have been several epidemics of food-borne diseases (FBD) about which there is lack of sufficient information for public health institutions to take appropriate measures. This study was conducted for the purpose of contributing to the dissemination of information on these diseases and their etiologic agents, epidemiology, and control. The study was based on data from 61 sources, including review articles, reports of outbreaks, and databases. Results reveal considerable underregistration and lack of data on FBD throughout the various countries, with viruses being the second most important cause of FBD in the United States of America. Two agents, Norwalk virus and hepatitis A virus, were the fifth and sixth most frequent causes, respectively, although the former was the single most frequent cause of FBD in 1982 and the second most frequent cause of water-borne diseases during the period from 1986 to 1988. Despite the scarcity of information on the problem, rotavirus, poliovirus, hepatitis E virus, astrovirus, and small gastroenteric viruses are also important causes of FBD. We also discuss the importance of viral zoonoses, especially hemorrhagic fevers transmitted by contact with rodent feces and tick-borne viral encephalitides (Lassa fever). There is discussion of the controversial mad cow disease and its potential transmission through food products, as well as of dietary aspects of the management of AIDS and other viral infections. Finally, measures for the prevention and control of FBD are described.

Detection of Norwalk virus and other genogroup 1 human caliciviruses by a monoclonal antibody, recombinant-antigen-based immunoglobulin M capture enzyme immunoassay.

Sera obtained from two groups of adult volunteers infected with Norwalk virus (NV) and two groups of patients involved in two natural outbreaks were tested for NV-reactive immunoglobulin M (IgM) by use of a monoclonal antibody, recombinant-antigen-based IgM capture enzyme immunoassay (EIA). No NV-reactive IgM was detected in the preinoculation sera of 15 volunteers, and 14 of 15 showed NV-reactive antibodies postinfection with NV. All of the volunteers showed IgG seroconversion to NV. In the outbreak studies, all 9 persons in one outbreak and 19 of 24 in another outbreak had NV-reactive IgM. In the first outbreak, only three of nine seroconverted to NV, which was likely due to late collection of acute-phase sera. In the second outbreak, 21 of 24 showed IgG seroconversion to NV. Sequencing of viruses isolated from five stool samples selected from those in the second outbreak showed that they were human calicivirus (HuCV) genogroup 1 viruses related, but not identical, to NV. In the volunteer studies, NV-reactive IgM was first detected 8 days postinoculation. The time of development of NV-reactive IgM antibodies in natural outbreaks was estimated to be similar to that found in the volunteer studies. Sera from three Hawaii virus-infected volunteers, four Snow Mountain virus patients, and 80 healthy individuals were negative for NV-reactive IgM, indicating test specificity for HuCV genogroup I infections. This capture IgM EIA is suitable for diagnosis of NV and other HuCV genogroup I infections and is especially useful when sera and fecal samples have not been collected early in the course of an outbreak.