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SUMMARYEuroRotaNet, 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 o1% 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.

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Infectious gastroenteritis is one of the most common diseases in young children. To clarify the infectious etiology of diarrhea in Danish children less than 5 years of age, we conducted a 2-year prospective case-control study. Stools from 424 children with diarrhea and 870 asymptomatic age-matched controls were examined, and their parents were interviewed concerning symptoms. Rotavirus, adenovirus, and astrovirus were detected by enzyme-linked immunosorbent assay, and norovirus and sapovirus were detected by PCR. Salmonella, thermotolerant Campylobacter, Yersinia, Shigella, and Vibrio spp. were detected by standard methods. Shiga toxinproducing (STEC), attaching-and-effacing (A/EEC), enteropathogenic (EPEC), enterotoxigenic, enteroinvasive, and enteroaggregative Escherichia coli were detected by using colony hybridization with virulence gene probes and serotyping. Parasites were detected by microscopy. Overall, a potential pathogen was found in 54% of cases. More cases than controls were infected with rotavirus, Salmonella, norovirus, adenovirus, Campylobacter, sapovirus, STEC, classical EPEC, Yersinia, and Cryptosporidium strains, whereas A/EEC, although common, was not associated with illness. The single most important cause of diarrhea was rotavirus, which points toward the need for a childhood vaccine for this pathogen, but norovirus, adenovirus, and sapovirus were also major etiologies. Salmonella sp. was the most common bacterial pathogen, followed by Campylobacter, STEC, Yersinia, and classical EPEC strains. A/EEC not belonging to the classical EPEC serotypes was not associated with diarrhea, underscoring the importance of serotyping for the definition of EPEC.Infectious gastroenteritis is one of the most common diseases in humans, with particularly high morbidity in children younger than 5 years of age (3). In industrialized countries, such as Denmark, the associated mortality is low, but the social burden and economic costs due to care of ill children and parents' absence from work are substantial because of the high incidence. Rotavirus is known to be the most common cause of severe acute, watery diarrhea in children under 5 years of age in industrialized and developing parts of the world (14, 43). In recent decades other new etiologies of diarrhea have been recognized, including noro-and sapovirus, Shiga toxin-producing Escherichia coli (STEC), and enteroaggregative E. coli (EAggEC). Furthermore, the incidence of food-borne Campylobacter and Salmonella infections has increased in many industrialized countries.Several case-control or cohort studies of enteropathogens associated with childhood diarrhea have been conducted in developing countries, but only a few analytical studies covering a broad range of newly discovered diarrheal agents have been undertaken in Europe (5,8,25,35). Many studies have focused on either bacterial or viral etiologies of diarrhea (7,27,38). The present study, comprising examinations for bacteria, virus, and parasites, was conducted to clarify the most common infectious etiol...

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A total of six point source outbreaks of norovirus infection from June to September 2005 in Denmark have now been linked to frozen raspberries imported from Poland.

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.

A total of 61 individuals involved in five norovirus outbreaks in Denmark were genotyped at nucleotides 428 and 571 of the FUT2 gene, determining secretor status, i.e., the presence of ABH antigens in secretions and on mucosa. A strong correlation (P ‫؍‬ 0.003) was found between the secretor phenotype and symptomatic disease, extending previous knowledge and confirming that nonsense mutations in the FUT2 gene provide protection against symptomatic norovirus (GGII.4) infections.Volunteer studies have shown that a subset of individuals are not affected by vomiting and diarrhea after challenges with noroviruses (1,16,19), and this information, together with the fact that attack rates seldom exceed 70% (4), suggests that inherited factors act to prevent certain individuals from symptomatic norovirus disease. Indeed, experimental and volunteer studies have indicated a correlation between secretor status and susceptibility to Norwalk virus (genogroup I norovirus) infections (3,12,14). These observations were recently confirmed and extended to also include authentic outbreaks by genogroup II viruses (17), which is the clinically most common genogroup of norovirus (9). Current knowledge thus suggests that secretor status determined by polymorphisms in the FUT2 gene is strongly associated with resistance to norovirus infections (3,11,12,17). Further support for this hypothesis is also the fact that nonsecretor and Lewis a-positive individuals have significantly lower antibody prevalence and titer to norovirus GGII than secretor and Lewis b-positive individuals (10). The association between secretor status and norovirus susceptibility is not fully understood, but transfection of the FUT2 gene to nonpermissive cells has been shown to increase cell susceptibility to norovirus infection (14), suggesting that the H antigen or a related structure acts as a receptor for the virus.FUT2 encodes an ␣(1,2)fucosyltransferase, which adds a fucose molecule to the H-type 1 precursor, giving the H-type 1 antigen. H-type 1 can, in contrast to its precursor, work as a precursor for the A and B blood group antigens. FUT2 determines the secretor status, which is the presence or absence of blood group ABH antigens on mucosal surfaces and in secretions such as saliva (5). Individuals carrying the secretor genotypes (SeSe or Sese) secrete the H antigen with or without A and/or B antigens, while individuals of the nonsecretor genotype (sese) do not. The polymorphisms found in the FUT2 gene show high ethnic specificity (8, 13), with a nonsense mutation at nucleotide 428 associated with the Caucasian populations (5, 8) The majority of the positive samples (90%) were submitted from hospitals, representing at least 30 different hospitals and situated in all parts of Denmark. For detection of norovirus in stool samples, purified viral RNA was reverse transcribed and PCR amplified (RT-PCR kit; QIAGEN, Hilden, Germany) by using the primers JV12 and JV13 essentially as described earlier (17,18). The PCR products (285 bp after trimming of the primer se...