Alicia Sánchez-Fauquier

Viruses causing gastroenteritis

Acute gastroenteritis is one of the most common diseases in humans worldwide. Viruses are recognized as important causes of this disease, particularly in children. Since the Norwalk virus was identified as a cause of gastroenteritis, the number of viral agents associated with diarrheal disease in humans has steadily increased. Rotavirus is the most common cause of severe diarrhea in children under 5 years of age. Astrovirus, calicivirus and enteric adenovirus are also important etiologic agents of acute gastroenteritis. Other viruses, such as toroviruses, coronaviruses, picobirnaviruses and pestiviruses, are increasingly being identified as causative agents of diarrhea. In recent years, the availability of diagnostic tests, mainly immunoassays or molecular biology techniques, has increased our understanding of this group of viruses. The future development of a safe and highly effective vaccine against rotavirus could prevent, at least, cases of severe diarrhea and reduce mortality from this disease.

Rotavirus genotypes co-circulating in Europe between 2006 and 2009 as determined by EuroRotaNet, a pan-European collaborative strain surveillance network

EuroRotaNet, a laboratory network, was established in order to determine the diversity of co-circulating rotavirus strains in Europe over three or more rotavirus seasons from 2006/2007 and currently includes 16 countries. This report highlights the tremendous diversity of rotavirus strains co-circulating in the European population during three years of surveillance since 2006/2007 and points to the possible origins of these strains including genetic reassortment and interspecies transmission. Furthermore, the ability of the network to identify strains circulating with an incidence of ≥1% allowed the identification of possible emerging strains such as G8 and G12 since the beginning of the study; analysis of recent data indicates their increased incidence. The introduction of universal rotavirus vaccination in at least two of the participating countries, and partial vaccine coverage in some others may provide data on diversity driven by vaccine introduction and possible strain replacement in Europe.

Rotavirus Surveillance in Europe, 2005–2008: Web-Enabled Reporting and Real-Time Analysis of Genotyping and Epidemiological Data

BACKGROUND The first European rotavirus surveillance network, EuroRotaNet, comprising 16 laboratories in 15 European countries, has been established. METHODS Fecal samples from gastroenteritis cases positive for group A rotavirus antigen were collected from multiple European countries from 2005 to mid-2008 and were subjected to G and P genotyping. Epidemiological data collected included age, sex, geographical location, setting, dates of onset and sample collection, and clinical symptoms. RESULTS A total of 8879 rotavirus-positive samples were characterized: 2129 cases were from the 2005-2006 season, 4030 from the 2006-2007 season, and 2720 from the ongoing 2007-2008 season. A total of 30 different G and P type combinations of strains circulated in the region from 2005 through 2008. Of these strains, 90% had genotypes commonly associated with human infections-G1P[8], G2P[4], G3P[8], G4P[8], and G9P[8]-and 1.37% represented potential zoonotic introductions. G1P[8] remained the most prevalent genotype in Europe as a whole, but the incidence of infection with G1P[8] rotavirus strains was <50% overall, and all 3 seasons were characterized by a significant diversity of cocirculating strains. The peak incidence of rotavirus infection occurred from January through May, and 81% of case patients were aged <2.5 years. Conclusions. Data gathered through EuroRotaNet will provide valuable background information on the rotavirus strain diversity in Europe before the introduction of rotavirus vaccines, and the network will provide a robust method for surveillance during vaccine implementation.

European Multicenter Evaluation of Commercial Enzyme Immunoassays for Detecting Norovirus Antigen in Fecal Samples

ABSTRACT A total of 2,254 fecal samples were tested in a European multicenter evaluation of commercially available norovirus antigen detection assays. Two commercial enzyme immunoassays, IDEIA Norovirus (Oxoid; Thermo Fisher Scientific, Ely, United Kingdom) and RIDASCREEN Norovirus (R-Biopharm, Darmstadt, Germany), were included in the evaluation, and their performance was compared with the results of reverse transcription-PCR (RT-PCR). Included in the evaluation were samples collected in sporadic cases of gastroenteritis, samples from outbreaks in which two or more samples were collected, well-characterized samples representing genotypes currently cocirculating within Europe, and samples collected from patients with gastroenteritis caused by a pathogen other than norovirus. The sensitivities and specificities of the IDEIA Norovirus and RIDASCREEN Norovirus assays were 58.93 and 43.81% and 93.91 and 96.37%, respectively, compared with RT-PCR. The sensitivities of both assays for outbreak investigations improved when six or more samples from an outbreak were examined. The IDEIA Norovirus assay exhibited reactivity to a broader range of norovirus genotypes than the RIDASCREEN Norovirus assay, which showed genotype-dependent sensitivities. The results indicate that, if used, these assays should serve as screening assays and the results should be confirmed by RT-PCR.

Human rotavirus G9 and G3 as major cause of diarrhea in hospitalized children, Spain.

A major shift in the predominant strains of rotavirus was detected.

First detection of group C rotavirus in children with acute diarrhea in Spain

Summary. Group C rotavirus causes sporadic cases and outbreaks of acute diarrhea in children and adults in many countries, but has never been detected among children in Spain. In a recently conducted surveillance study to screen fecal specimens for bacteria and viruses from a cohort of 822 young children who were treated for acute diarrhea in Madrid, no pathogens were detected in fecal specimens from 238 (29%) children. In this study, we examined 147 of those specimens for group C rotavirus by EIA and PCR and found 22 (15%) were positive. Our findings demonstrate that group C rotavirus is an important cause of childhood diarrhea in Spain.

Prevalence and Clinical Characteristics of Norovirus Gastroenteritis Among Hospitalized Children in Spain

Background: The importance of norovirus as a cause of gastroenteritis outbreaks is well documented, but the role of norovirus in sporadic acute severe gastroenteritis is not so well established. The aim of this study was to determine the prevalence and clinical characteristics of norovirus gastroenteritis among hospitalized children. Methods: A prospective study was conducted in children less than 5 years old, admitted with acute gastroenteritis between January 2005 and January 2008 to the Pediatrics Department of the Universitary Hospital, Albacete, Spain. Demographic and clinical data were collected. A stool sample from each child was screened for enteropathogenic bacteria and tested by reverse transcription polymerase chain reaction for rotavirus, astrovirus, norovirus, and sapovirus and by immunochromatographic method for enteric adenoviruses. Results: Norovirus was the second most frequent pathogen after rotavirus, being detected in 61 (17.3%) of the 352 children enrolled, in 29 of them (8.2%) as single agent. Mixed infections involving other viruses or bacteria were present in 52.4% of norovirus positive samples, a nosocomial source of infection was demonstrated in 17.2%. Norovirus infection was more prevalent in winter and affected mainly children less than 2 years of age. Vomiting was present in 68% and fever in 48.3% of cases, 3 children had nonfebrile seizures. Compared with rotavirus enteritis, norovirus infection was slightly less severe (in terms of severity score and need of intravenous rehydration) and fever was less frequent. Conclusions: Norovirus was a frequent cause of acute severe sporadic gastroenteritis in children representing the second etiologic agent after rotavirus.

Diversity of Group A Human Rotavirus Types Circulating over a 4-Year Period in Madrid, Spain

ABSTRACT The incidence and distribution of human rotavirus G types among children under 5 years old with acute gastroenteritis were determined over a 4-year period (1998 to 2002) by using monoclonal antibodies and reverse transcription-PCR methods. Rotavirus was detected in 1,155 (31%) of 3,760 specimens tested. Rotavirus was studied in every month of the 48-month survey period. Rotavirus activity occurred mainly (51%) in the typically cooler months in Spain (November to February). The age distribution of rotavirus-positive cases showed that 90% of patients (1,038 of 1,155) were under 2 years old. Rotavirus types were determined for 576 of 1,155 patients (50%). G1 was the main genotype detected (53%), and the second most common was G4 (24%). The G2, G9, and G3 rotavirus types were detected in 14, 6, and 2% of the cases, respectively. Dual infections were detected in only 0.6%. The seasonal distribution of genotypes showed a significant genotypic shift: whereas G4 strains predominated (57%) during the 1998 to 2000 seasons, the G1 gradually increased to account for 75% in the 2000 to 2002 seasons. In addition, the present study reports the first detection of the G9 genotype in human fecal samples in Spain. Therefore, additional types may be required for vaccine development strategies that currently target only types G1 to G4.

New Immunochromatographic Method for Rapid Detection of Rotaviruses in Stool Samples Compared with Standard Enzyme Immunoassay and Latex Agglutination Techniques

Abstract. Three different commercial immunologic tests for rapid detection of group A rotavirus (an immunochromatographic method, latex agglutination, and enzyme immunoassay) were used to evaluate 228 faecal specimens obtained from Spanish children with acute gastroenteritis. After resolution of 30 (13.2%) discordant results by reverse transcription-polymerase chain reaction for rotavirus, the statistical values of the enzyme immunoassay, latex agglutination, and immunochromatographic method were respectively 96%, 68%, and 99% for sensitivity; 99%, 99%, and 96% for specificity; 98%, 96%, and 92% for positive predictive value; and 98%, 88%, and 99% for negative predictive value. The immunochromatographic technique showed high sensitivity and specificity and was rapid and easy to perform in the routine clinical laboratory.

Isolation of cross-reactive, subtype-specific monoclonal antibodies against influenza virus HA1 and HA2 hemagglutinin subunits

SummaryThe large (HA1) and small (HA2) subunits of influenza virus A/Vict/3/75 hemagglutinin were purified in denatured form by preparative electrophoresis. Both polypeptides were used to immunize mice from which monoclonal antibodies were obtained. These antibodies reacted not only with the corresponding hemagglutinin subunit but also with purified virions. When tested by radioimmunoassay against a panel of human viruses, most anti-HA1 and -HA2 antibodies behaved as subtype-specific, whereas anti-HA antibodies, raised against purified virus, were more restricted. The anti-subunit antibodies were negative in hemagglutination-inhibition and neutralization tests. The interest of these antibodies as reagents for research and diagnosis is discussed.