Outbreaks of gastroenteritis linked to lettuce, Denmark, January 2010

At least 11 linked outbreaks of gastroenteritis with a total of 260 cases have occurred in Denmark in mid January 2010. Investigations showed that the outbreaks were caused by norovirus of several genotypes and by enterotoxigenic Escherichia coli. Lettuce of the lollo bionda type grown in France was found to be the vehicle.

[Hepatitis E transmission in Denmark]

A case of acute hepatitis due to hepatitis E virus genotype 3 was diagnosed by serology and genomic sequencing. Phylogenetic analysis demonstrated a strain identical to one isolated from a Swedish pig, which supports the hypothesis that swine serves as reservoirs for HEV infection. The patient did not have any recent travel history, had experienced no contact with animals and the origin of the infection remained unknown. We emphasize that health personnel should be aware of acute hepatitis E even among patients without a travel history.

Incidence and cause of aplastic anemia, hemolytic anemia, agranulocytosis and thrombocytopenia

A total of 745 patients with cytopenia (aplastic anemia 157, hemolytic anemia 101, agranulocytosis 136, thrombocytopenia 351) were diagnosed during a 5-year period in a health care region comprising 16% of the Swedish population. The total incidence was for aplastic anemia 24.6, hemolytic anemia 15.8, agranulocytosis 21.3 and thrombocytopenia 55.0 cases per 10(6) and year. Compared to 10 years earlier, aplastic anemia and agranulocytosis have become more common, thrombocytopenia occurs with unchanged frequency while hemolytic anemia is rarer. The overall incidence is 5 times higher in elderly (greater than 65 y.) than in younger patients and 1.3 times higher in women than in men, figures that make total incidence figures rather meaningless. The most common cause is "unknown" (45%), the next drug-induced (25-36% including cytostatic drugs). Disregarding cytostatics, the drugs most often encountered are oral diuretics, analgesics, antiphlogistics and sulfonamides.

Lung function and bronchial responsiveness after Mycoplasma pneumoniae infection in early childhood

Mycoplasma (M.) pneumoniae has been associated with exacerbation of symptoms in asthmatic school children and adults; and an etiological role in asthma has been suggested. The purpose of this study was to investigate whether infection with M. pneumoniae in early childhood has a long-term influence on lung function and bronchial responsiveness. In a retrospective, clinical cohort-study children younger than 5 years-of-age when PCR-tested for M. pneumoniae were enrolled. Sixty-five children with clinical symptoms suggesting infection with M. pneumoniae during an epidemic season completed a clinical follow-up examination including lung function testing (28 PCR-positive and 37 PCR-negative). In addition to the PCR-test for M. pneumoniae all respiratory tract specimens were additionally tested for other atypical bacteria and for viruses by PCR. Lung function was measured as specific airway resistance by whole-body plethysmography and bronchial hyperresponsiveness was assessed by cold, dry air hyperventilation. Neither baseline lung function nor bronchial response to cold dry air hyperventilation differed between M. pneumoniae-positive and -negative children: mean baseline lung function were 1.17 versus 1.21 (kPa sec), P = 0.45; and mean change in specific resistance was 13% versus 9%, P = 0.42. In conclusion, M. pneumoniae infection in early childhood was not associated with long-term effects on lung function and bronchial hyperresponsiveness 2 years after infection.

Data quality of 5 years of central norovirus outbreak reporting in the European Network for food-borne viruses

BACKGROUND

The food-borne viruses in Europe (FBVE) network database was established in 1999 to monitor trends in outbreaks of gastroenteritis due to noroviruses (NoVs), to identify major transmission routes of NoV infections within and between participating countries and to detect diffuse international food-borne outbreaks.

METHODS

We reviewed the total of 9430 NoV outbreak reports from 13 countries with date of onset between 1 January 2002 and 1 January 2007 for representativeness, completeness and timeliness against these objectives.

RESULTS

Rates of reporting ranged from a yearly average of 1.8 in 2003 to 11.6 in 2006. Completeness of reporting of an agreed minimum dataset improved over the years, both for epidemiological and virological data. For the 10 countries that provided integrated (epidemiological AND virological) reporting over the 5-year period, the completeness of the minimum dataset rose from 15% in 2003 to 48% in 2006. Two countries have not been able to combine both data types due to the structure of the national surveillance system (England and Wales and Germany). Timeliness of reporting (median days between the onset of an outbreak and the date of reporting to the FBVE database) differed greatly between countries, but gradually improved to 47 days in 2006.

CONCLUSION

The outbreaks reported to the FBVE reflect the lack of standardization of surveillance systems across Europe, making direct comparison of data between countries difficult. However, trends in reported outbreaks per country, distribution of NoV genotypes, and detection of diffuse international outbreaks were used as background data in acute questions about NoV illness and the changing genotype distribution during the 5-year period, shown to be of added value. Integrated reporting is essential for these objectives, but could be limited to sentinel countries with surveillance systems that allow this integration. For successful intervention in case of diffuse international outbreaks, completeness and timeliness of reporting would need to be improved and expanded to countries that presently do not participate.

Host genetic resistance to symptomatic norovirus (GGII.4) infections in Denmark

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.

[Primary cytomegalovirus infection and thrombophlebitis/pulmonary embolism]

A young woman was admitted to hospital with suspected pyelonephritis. Due to prolonged fever, further investigations were done and showed a thrombosis in her femoral vein; X-ray and lung scintigraphy revealed a pulmonary embolism. Blood tests showed lymphocytosis, and a primary cytamegalovirus (CMV) infection was confirmed by serology and PCR. The patient was a smoker and obese and was taking oral contraceptives; a factor V Leiden mutation was also found. Deep-vein thrombosis is a rare but severe complication of a primary CMV infection that is also seen in immunocompetent persons.

[Measles in two children and one adult--outbreak of measles genotype B3]

Measles virus genotype B3 was isolated from patients during a measles outbreak in Copenhagen starting January 2006. Here we describe three cases: two children aged 9 and 22 months, respectively, and a 29-year-old man. All three patients were hospitalised. Several doctors examined both the children before the diagnosis of measles was established. The patients were not vaccinated against measles. They had not been abroad within the last three weeks. Genotype B3 is endemic in West and Central Africa. The genotype B3 detected in these cases was different from the B3 seen in recent outbreaks in Europe.

Confirmation of electron microscopy results by direct testing of viruses adhered to grids using nucleic acid amplification techniques

It is possible to visualize rapidly viral particles by electron microscopy (EM) in patient samples and in cell cultures, and characterize the particles on the basis of their size and morphology. In many instances, EM has contributed to the diagnosis of specific infectious agents. Four different types of viruses with different characteristics of particle size, capsid structure, the presence or absence of an envelope, genomic content and stability outside the host were screened and diagnosed by EM at the level of family/genus. The results were confirmed at the species level by elution of the sample material from the grids used for EM examination and nucleic acid amplification. This approach could be valuable in situations where the immediate diagnosis is unclear, or when new infectious agents appear.

Risk Factors for Diarrhea Among Children in an Industrialized Country

BACKGROUND

Risk factors for childhood diarrhea in industrialized countries are not well characterized, although diarrhea remains an important cause of morbidity.

METHODS

We conducted a case-control study of 422 cases and 866 controls over 22 months in Denmark. We selected cases among children under 5 years of age with diarrhea. Age-matched healthy controls were selected from the background population using a population register. Parents were interviewed about possible exposures and underlying conditions. In addition, stool samples from both cases and controls were analyzed for viruses, parasites, and bacteria. We analyzed risk factors for diarrhea in general and for diarrhea of a viral, bacterial, or "unknown" etiology using logistic regression.

RESULTS

The following factors were independently associated with an increased risk of diarrhea: recent foreign travel, contact with symptomatic persons (particularly in daycare centers), hospitalization, contact with a dog with diarrhea, private daycare, consumption of products containing formula milk, unemployment and low educational status of parents, and prior diagnosis of several types of atopic diseases. In a pathogenic-specific analysis of diarrhea of bacterial (73 patients), viral (88), or "unknown" (222) etiology, the major risk factor for viral diarrhea was contact with symptomatic persons. For bacterial diarrhea, foreign travel and socioeconomic factors were the main risk factors.

CONCLUSIONS

Viral diarrhea appears to be transmitted predominantly from person to person, whereas bacterial diarrhea appears to be primarily foodborne. A substantial portion of the diarrheal episodes may be of noninfectious etiology. Limiting child-to-child transmission of disease in daycare centers may substantially reduce the disease burden.

Imported frozen raspberries cause a series of norovirus outbreaks in Denmark, 2005

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.

Etiology of diarrhea in young children in Denmark: a case-control study

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 toxin-producing (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.

Characterization of rotavirus strains in a Danish population: high frequency of mixed infections and diversity within the VP4 gene of P[8] strains

We characterized the G and P types from 162 rotavirus-positive stool specimens collected from 162 persons in Denmark (134 children and 28 adults) with acute diarrhea in 1998, 2000, and 2002. Samples were obtained during outpatient consultations (73%) and from hospitalized patients (27%). Although more than 20 different G-P combinations were identified, only 52% represented the globally most common types G1P[8], G2P[4], and G4P[8]. The G9 genotype, which is emerging worldwide, was identified in 12% of all samples. Twenty-one percent of the samples were of mixed genotypic origin, which is the highest frequency reported in any European population. The standard reverse transcription-PCR methods initially failed to identify a considerable fraction of the rotavirus P strains due to mutations at the VP4 primer-binding sites of P[8] strains. The application of a degenerate P[8] primer resulted in typing of most VP4 strains. There was considerable year-to-year variation among the circulating G-P types, and whereas G1P[8] was predominant in 1998 (42% of samples) and 2002 (26%), G2P[4] was the strain that was most frequently detected in 2000 (26% of samples). Our findings might implicate challenges for rotavirus vaccine implementation in a European population and underscore the importance of extensive strain surveillance prior to, during, and after introduction of any vaccine candidate.

An unusual enterovirus outbreak in Denmark: clinical characteristics and molecular epidemiology

In 2000, a large enterovirus (EV) outbreak was seen in Denmark; the number of patients with a verified EV infection was 3-fold higher compared to previous y. Echovirus 30 (E30) was the dominant EV type and was detected in 31% of all 306 EV positive patients and in 61% of the 155 patients in whom typing was successful. The outbreak started in February and peaked in June, which is unusually early in a temperate climate and not registered before in Denmark. The age distribution of the patients also differed from previous y with a significantly higher proportion of older children and adults being affected. The patients had mainly symptoms consistent with aseptic meningitis. A phylogenetic analysis based upon a part of the VP1 structural gene of 21 E30 isolates showed that the Danish isolates belonged to the E30 genotype which has prevailed in Europe during the last few years. However, they constituted a separated cluster compared with 2 other outbreaks in other parts of Europe in 2000.

Sexually Transmitted Infections in Rural Madagascar at an Early Stage of the HIV Epidemic

BACKGROUND AND OBJECTIVES

Sexually transmitted infections (STIs) in Madagascar have primarily been monitored in selected groups of patients attending STI clinics in major cities as part of the HIV surveillance program in Madagascar.

GOAL OF THE STUDY

The aim of the study was to provide complementary data related to STI prevalence in a general rural population.

STUDY DESIGN

STIs were investigated in 643 subjects aged 15 to 49 years as part of a cross-sectional morbidity study of urogenital schistosomiasis. Infection rates were reassessed 3 weeks and 6 months after systematic STI treatment at baseline.

RESULTS

Neisseria gonorrhoeae (Ng), Chlamydia trachomatis (Ct), Mycoplasma genitalium (Mg), Trichomonas vaginalis (Tv), and/or antibodies to Treponema pallidum (Tp) were diagnosed in 125 (37.5%) of 333 women and in 83 (26.8%) of 310 men. In addition, 49% of the women and 28% of the men were infected with herpes simplex virus-2. Six (0.9%) subjects were found HIV-antibody positive. Between the 3-week and 6-month follow-up surveys Ng, Ct, and/or Mg prevalence increased most prominently in women aged 15 to 24 years.

CONCLUSION

Study findings suggest that rural areas in Madagascar should be as closely monitored and assisted in STI and HIV control as their urban counterparts. Following the current consensus, young adults should constitute a priority target group in the control programs.

Changing epidemiology of HBV infection in Danish children

Hepatitis B continues to be a worldwide threat to human health, especially if infection occurs in childhood. Universal vaccination is recommended by WHO, but has not been implemented in the Scandinavian countries, Holland and UK, because of a low incidence rate. However, clinically overt infections are rare in childhood. We therefore performed a nation wide serosurvey for HBV markers in 2428 children aged primarily 6-16 years from 16 primary schools in Denmark. Anti-HBc was found in altogether 20 children (0.8%), 12 of whom were among 144 immigrant children (8.3%) compared to 8 (0.4%) in those born in Denmark. Three of the children, all immigrants, were HBsAg positive indicating chronic infection. At school level no relation of anti-HBc in Danish born children was found to schools with high number of immigrant children or schools with HBsAg positive children indicating a low risk of Hepatitis B transmission in this setting. The results do not support implementation of general vaccination, but stress the need for HBV screening in immigrants as it provides a mean for immunization of close contacts at risk and information on prevention.

[Fever and skin hemorrhages in children--is it meningococcal disease?]

INTRODUCTION

Our main aims were to establish criteria for early distinction between meningococcal disease and other conditions with similar clinical features, and to identify other causes of haemorrhagic rashes accompanied by fever.

MATERIALS AND METHODS

This prospective study comprised 264 infants and children hospitalised with fever and skin haemorrhages.

RESULTS

We identified an aetiological agent in 28%: 15% had meningococcal disease, 2% another invasive bacterial infection, 7% enterovirus infection, and 4% adenovirus infection. Five clinical variables discriminated meningococcal disease from other conditions on admission: skin haemorrhages of (1) characteristic appearance; (2) universal distribution and (3) a maximum diameter of > 2 mm; (4) poor general condition; and (5) nuchal rigidity.

DISCUSSION

If any two or more of these clinical variables were present, the probability of identifying a patient with meningococcal disease was 97% and the false-positive rate was only 12%. This diagnostic algorithm did not identify children in whom septicaemia was caused by other bacterial species.

Characterization of two decades of temporal co-circulation of four mumps virus genotypes in Denmark: identification of a new genotype

Twenty-nine Danish virus isolates and 14 serum samples from patients with mumps were genotyped by nucleotide sequencing of the small hydrophobic (SH) protein gene and the deduced 57 amino acid sequences were aligned with sequences of mumps virus strains published previously. Four neurovirulent genotypes of the SH protein gene, genotypes C, D, H and a new genotype, designated J, were found. There was a dynamic fluctuation of the different genotypes over the two decade period of time. Genotype J was found from 1981 to 1988; genotypes C and H exhibited a similar distribution in time. Genotype D was found between 1979 and 1982, it then disappeared and reappeared again in 1996. From 1996 onwards, genotype D was found to be the predominant genotype, which is in contrast to the situation seen in the neighbouring country of Sweden, where, since 1985, only genotype A has been found.

Diagnostic assessment of haemorrhagic rash and fever

AIMS

To establish criteria for early distinction between meningococcal disease and other conditions with similar clinical features, and to identify other causes for haemorrhagic rashes accompanied by fever.

METHODS

In a prospective study, 264 infants and children hospitalised with fever and skin haemorrhages were studied.

RESULTS

We identified an aetiological agent in 28%: 15% had meningococcal disease, 2% another invasive bacterial infection, 7% enterovirus infection, and 4% adenovirus infection. Five clinical variables distinguished between meningococcal disease and other conditions on admission: (1) skin haemorrhages of characteristic appearance; (2) universal distribution of skin haemorrhages; (3) maximum diameter of one or more skin haemorrhages greater than 2 mm; (4) poor general condition (using a standardised observation scheme); and (5) nuchal rigidity. If any two or more of these clinical variables were present, the probability of identifying a patient with meningococcal disease was 97% and the false positive rate was only 12%. This diagnostic algorithm did not identify children in whom septicaemia was caused by other bacterial species.

[Complications in two children with acute lymphatic leukemia caused by vaccination against varicella zoster virus]

Complications in two varicella zoster virus (VZV) vaccinated children with leukemia in remission are reported. Case I presented with varicella on day 30 after vaccination, with a relapse on day 49 and development of zoster on day 70. VZV was detected in vesicles by PCR on days 49 and 70. Case II presented with varicella on day 32 after vaccination, and VZV was detected in vesicles and nasal secretion. The manifestations were mild and responded to treatment. PCR methods were directed toward the R5 and PS regions. The virus from the two children was unambiguously identified as the Oka vaccine strain. The majority of Danish field strains had only one copy of the 112 basepair repeat element in the R5 region, but two, four and presumably higher copy numbers were also seen. All Danish field strains had the Pst1 cleavage site in the PS region.

Induction of protein inhibitor of neuronal nitric oxide synthase/cytoplasmic dynein light chain following cerebral ischemia

Administration of inhibitors of neuronal nitric oxide synthase or deletion of the encoding gene in rodents provided evidence that neuronal nitric oxide synthase activity may contribute to neuronal cell death following global and focal cerebral ischemia. In the present study, we investigated by in situ hybridization the expression of an endogenous inhibitor of neuronal nitric oxide synthase activity, designated protein inhibitor of neuronal nitric oxide synthase and homologous to cytoplasmic dynein light chain, in the post-ischemic rat brain. Following global ischemia induced by cardiac arrest, messenger RNA expression of protein inhibitor of neuronal nitric oxide synthase was rapidly induced in pyramidal neurons of the hippocampal CA3 region and granule cell of the dentate gyrus which are resistant to ischemic damage. In vulnerable CA1 pyramidal neurons however, protein inhibitor of neuronal nitric oxide synthase expression remained at basal level after global ischemia and was associated with an increase in nicotinamide adenine dinucleotide phosphate-diaphorase activity and subsequent DNA fragmentation indicating ischemia-mediated neuronal cell death. Following focal cerebral ischemia induced by permanent occlusion of the middle cerebral artery, transcripts of protein inhibitor of neuronal nitric oxide synthase progressively accumulated in cortical neurons bordering the infarct area. After transient middle cerebral artery occlusion however, messenger RNA levels of protein inhibitor of neuronal nitric oxide synthase increased in the reperfused neocortex. Our findings indicate that cerebral ischemia leads to an increase in neuronal expression of protein inhibitor of neuronal nitric oxide synthase in brain regions where sustained or "uncoupled" nitric oxide synthase activity may be detrimental to neurons. Lack of post-ischemic induction of protein inhibitor of neuronal nitric oxide synthase in CA1 pyramidal neurons may result in high nitric oxide synthase activity after global ischemia and could contribute to delayed neuronal cell death.

Expression of nuclear redox factor ref-1 in the rat hippocampus following global ischemia induced by cardiac arrest

The Ref-1 protein is a bifunctional nuclear enzyme involved in repair of DNA lesions and in redox regulation of DNA-binding activity of AP-1 family members, such as Fos and Jun transcription factors. In the present study, we demonstrate by in situ hybridization that transient global ischemia induced by cardiac arrest activates ref-1 mRNA expression in the granular cells of the rat dentate gyrus after 6 h and in CA1 pyramidal neurons of the hippocampus proper after 24 h, respectively. Immunohistochemical analysis revealed nuclear accumulation of Ref-1 protein in granular cells of the ischemia-resistant dentate gyrus, whereas Ref-1 protein expression progressively decreased in vulnerable CA1 neurons of the post-ischemic hippocampus from 24 h onwards. At the same time point, intense nuclear c-Jun immunoreactivity was observed in both neuronal cell populations. Our data suggest that oxidative stress induced by ischemia-reperfusion may increase neuronal ref-1 expression. However, inability of ref-1 mRNA translation and nuclear translocation of encoded protein in CA1 pyramidal neurons may inhibit repair of oxidative DNA damage or cellular adaptive responses leading to delayed neuronal cell death.

Activation of CPP-32 protease in hippocampal neurons following ischemia and epilepsy

Recent in vitro studies indicate an involvement of members of the interleukin-1beta converting enzyme (ICE) family of proteases in programmed neuronal cell death. Cell death of hippocampal neurons in animal models of cerebral ischemia and epilepsy shows morphological features of apoptosis and can be prevented by administration of protein synthesis inhibitors suggesting that de novo synthesis of components of the cell death program is necessary for neuronal apoptosis. In the present study we demonstrate by in situ hybridization analysis that expression of CPP-32, an ICE-related protease, is significantly upregulated in CA1 hippocampal neurons following global ischemia induced by cardiac arrest and in hippocampal neurons of the CA3/CA4 region after kainate-mediated epilepsy, respectively. Moreover, an increase in CPP-32-like proteolytic activity was detected in hippocampal extracts 24 h after ischemia using the fluorogenic CPP-32 substrate Ac-DEVD-AMC. Activation of CPP-32 clearly preceded cell death of hippocampal neurons as assessed by in situ end-labelling of nuclear DNA fragments. These results indicate that CPP-32 protease may be activated at both the transcriptional and post-translational level during neuronal apoptosis and that activation correlates with the selective vulnerability of hippocampal pyramidal neurons to ischemic and epileptic insults.

Maturation of rubella IgG avidity over time after acute rubella infection

BACKGROUND

As the incidence of rubella has diminished, the proportion of unspecific rubella IgM reactivity among all samples with rubella IgM reactivity has increased. It is important to distinguish IgM reactivity caused by primary infection from that caused by reinfection or persistence, especially in pregnant women, as termination of pregnancy should be considered when primary rubella is diagnosed during the first trimester.

OBJECTIVES

To elucidate the changes over time of the avidity of rubella IgG antibodies after acute rubella infection.

STUDY DESIGN

Serial samples, 84, were collected from 15 patients up to 4-5 months after acute rubella infection. Rubella specific IgG avidity was tested by the eluting principle adding 35 mM diethylamine to the washing buffer of a commercially available rubella IgG ELISA. As controls, 137 samples from women with remote rubella and 94 samples from patients with a rubelliform rash, were tested.

RESULTS

The avidity index increased steadily in all patients during the observation time. A low avidity index (< 40%) was seen up to 6 weeks after onset of rash. A high avidity index (> 60%) was not observed until 13 weeks after infection and only in four of the 15 patients during the observation time.

CONCLUSIONS

An increase of rubella IgG antibody avidity was seen during the whole observation time but was most pronounced during the first 3 months after onset of rash. Measurement of rubella IgG avidity is a good supplemental test for cases with rubella IgM reactivity to confirm or exclude a recent rubella infection.