A foodborne outbreak of Cryptosporidium hominis infection.

Foodborne outbreaks of cryptosporidiosis are uncommon. In Denmark human cases are generally infrequently diagnosed. In 2005 an outbreak of diarrhoea affected company employees near Copenhagen. In all 99 employees were reported ill; 13 were positive for Cryptosporidium hominis infection. Two analytical epidemiological studies were performed; an initial case-control study followed by a cohort study using an electronic questionnaire. Disease was associated with eating from the canteen salad bar on one, possibly two, specific weekdays [relative risk 4.1, 95% confidence interval (CI) 2.1-8.3]. Three separate salad bar ingredients were found to be likely sources: peeled whole carrots served in a bowl of water, grated carrots, and red peppers (in multivariate analysis, whole carrots: OR 2.1, 95% CI 1.1-4.0; grated carrots: OR 2.1, 95% CI 1.2-3.9; peppers: OR 3.3, 95% CI 1.7-6.6). We speculate that a person excreting the parasite may have contaminated the salad buffet.

A role of late Epstein-Barr virus infection in multiple sclerosis.

OBJECTIVE: To assess Epstein-Barr virus (EBV) seroconversion in a high multiple sclerosis (MS) prevalence area and to evaluate the recall of diagnosed infectious mononucleosis in MS patients. METHODS: The study was based on information or blood samples, or both, from schoolchildren, young MS patients and matched controls. EBV serology was performed on 1154 blood samples. RESULTS: We demonstrate that more than one third of the population in a high MS prevalence area is seronegative to EBV at puberty. This is in contrast to the virtually complete seroconversion to EBV early in life in individuals from areas with a low prevalence of MS. Furthermore, we demonstrate that recall of diagnosed infectious mononucleosis (IM), but not recall of common childhood diseases, is significantly more frequent among MS patients than healthy controls. All MS patients, including patients without prior immunosuppressive treatment, were EBV seropositive. CONCLUSION: During or after puberty, EBV is transmitted to a major proportion of the population in an MS high-prevalence area. Together with our previous documentation of an association between late infection with EBV and an increased risk of developing MS, these data support a role of EBV infection in MS.

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.

Sero-epidemiology of mumps in western Europe.

Six countries (Denmark, England and Wales, France, Germany, Italy and The Netherlands) conducted large serological surveys for mumps, in the mid-1990s, as part of the European Sero-Epidemiology Network (ESEN). The assay results were standardized and related to the schedules and coverage of the immunization programmes and the reported incidence of mumps. Low incidence of disease and few susceptibles amongst adolescents and young adults was observed in countries with high mumps vaccine coverage (e.g. The Netherlands). High disease incidence and large proportions of mumps virus antibody negative samples in adolescent and young adult age groups was noted in countries with poor vaccine coverage (e.g. Italy). The build-up of susceptibles in older children and adolescents in England and Wales, France, the former West Germany and Italy indicate the possibility of further mumps outbreaks in secondary school environments. To control mumps in western Europe, current MMR immunization programmes will need to be strengthened in a number of countries. Sero-surveillance of mumps is an important component of disease control and its usefulness will be enhanced by the development of an international mumps standard.

[Cases of measles in Denmark are caused by reintroduction of virus from abroad]. / Maeslingetilfaelde i Danmark skyldes gentagne introduktioner af virus fra udlandet.

Measles vaccination was implemented in the child vaccination programme in Denmark in 1987 and produced a rapid decline in the incidence. Few cases were recorded annually until 1999. The measles virus isolated in Denmark during 1997-1998 was compared by partial sequencing of the haemagglutinin-coding region with Danish strains from the prevaccination era collected in 1965-1983, as well as with representatives of globally circulating strains of today. The dissimilarity of the prevaccination era strains identified in Denmark in 1997-1998 along with the similarity of these five strains with globally circulating strains at present, substantiate the conclusion that there is no persistent circulation of the measles virus in Denmark.

The seroepidemiology of measles in Western Europe.

The European Regional Office of WHO has targeted measles for elimination from the region in 2007. Large national, age and sex stratified serological surveys of measles antibody were conducted in seven Western European countries from 1994-8 as part of the European Seroepidemiology Network. Three patterns were observed in the country-specific measles seroprofiles, ranging from (very) low susceptibility (four countries) to high susceptibility (one country). Susceptibility levels amongst 2-4-year-olds ranged from 2.9 to 29.8%, in 5-9-year-olds from 2.5 to 25% and 10-19-year-olds from 2.1% to 13.9%. A country's susceptibility profile was highly associated with vaccine coverage for the first dose. First dose coverage ranged from 91 to 97.5% for low susceptibility countries, 75 to 85% for intermediate susceptibility countries and 55% for the high susceptibility country. Only the high susceptibility country still reports epidemic measles. In low susceptibility countries, which have achieved or are very close to measles elimination, the priority will be to maintain high MMR vaccine coverage in all geopolitical units for both vaccine doses. In moderate susceptibility countries there is still some endemic transmission, but also risk of outbreaks as pools of susceptibles accumulate. In the high susceptibility country the priority will be to increase infant vaccine coverage and reduce regional variation in coverage levels.

The seroepidemiology of rubella in western Europe.

Most of the countries in western Europe have now implemented mass infant rubella immunization programmes, instead of or in addition to selective vaccination in order to achieve the elimination of congenital rubella syndrome. The European countries Denmark, England and Wales, Finland, France, Germany, Italy and the Netherlands undertook large, national serological surveys collecting several thousand serum specimens during 1994-8. Antibodies against rubella virus were detected by a variety of enzyme immuno-assays. Comparability of the assay results was achieved by a standardized methodology. The age- and sex-stratified serological results were related to the schedules, coverage of rubella vaccination and the incidence in these countries. The results show widely differing levels of immunity to rubella both in the general population and in the specific age groups of males and females. A low rate (< 5%) of susceptibles in childhood and adolescents of both sexes was obtained only in Finland and the Netherlands. Countries such as Italy with only moderate coverage for the infant immunization programme currently have both high susceptibility levels in the general population and in the at-risk population. The likelihood is of continued epidemics of rubella with cases of congenital rubella syndrome. The continued implementation of selective vaccination will help to offset the impact of this ongoing transmission and to protect women on reaching childbearing age.

Sequence analysis of the hemagglutinin gene of measles virus isolates in Denmark 1997-1998: no evidence of persistent circulation of measles virus in Denmark.

The hemagglutinin-coding region of 17 virus samples from 12 measles cases in Denmark during 1997-1998 was analysed by partial nucleotide sequencing. The cases appeared as three sporadic cases and two epidemics, both with a limited time course and geographical distribution. The measles strains identified from the three sporadic cases and two epidemics could be allocated to five different previously well-defined sequence groups consistent with the assumption that cases of measles in Denmark are due to repeated introduction from abroad rather than persistent circulation of strains in the population.

Gait disturbance interpreted as cerebellar ataxia after MMR vaccination at 15 months of age: a follow-up study.

Measles, mumps and rubella (MMR) vaccination was included in the Danish childhood vaccination programme in 1987. During the following 10-y period, 550 notification records of adverse events after MMR vaccination at 15 mo of age have been registered, and a total of 41 notifications have included "gait disturbance". This corresponds to a frequency of 8 per 100,000 doses of MMR vaccine used for 15-mo-old children. The symptoms and signs are characteristic of cerebellar ataxia. In 28 notifications, the descriptions by the doctors included only "gait disturbance", while in 13 an additional interpretation was included. Thirty-two parents (78%) filled in a questionnaire and 26 (63%) agreed to participate in a clinical follow-up study. The gait disturbance symptoms mainly occurred 7-14 d after the vaccination, and the duration was median 1-2 wk (range 1 d to more than 4 mo). One-third of the children had symptoms lasting more than 2 wk. Significantly more children with long duration of symptoms had some kind of complaint or clinical signs at the follow-up in 1997. Gait disturbance registered after MMR vaccination seems to be more frequent than hitherto reported. Most cases are mild and short-lasting and a longer duration of symptoms seems to be predictive of late sequelae. A clinical diagnosis of cerebellar ataxia after MMR and the exact frequency of this adverse event remains to be tested in prospective studies.

Immune response to diphtheria booster vaccine in the Baltic states.

A study was done to measure baseline levels of immunity to diphtheria and antibody responses to different doses of diphtheria vaccine in study participants in the three Baltic states. Diphtheria booster vaccines containing either 3 (Estonia and Lithuania), 6 (Latvia), or 12 (Latvia) limit of flocculation units of diphtheria toxoid were administered to 2315 adults. Diphtheria antibody levels were tested before and 1-2 months after vaccination. Before vaccination, 40% of the participants in Estonia, 32% in Lithuania, and 38% in Latvia had antibody levels <0.01 IU/mL, the level for minimum protection. After vaccination, 79% of the participants in Estonia, 83% in Lithuania, and 81% in Latvia had antibody levels >0. 1 IU/mL, the minimum level for full protection. However, in each of the countries, about one-third of the 40- to 49-year-old participants would have benefited from additional doses of vaccine. There was not a significantly different antibody response among persons receiving the three different doses. Age and the level of prevaccination immunity had a modifying effect on the response to vaccination; however, sex did not.

Infant BCG vaccination study in Lithuania.

SETTING: Infants identified in maternity hospitals in Vilnius, Lithuania. OBJECTIVES: To test the capacity of the BCG vaccine, Danish strain 1331 (Danish vaccine), to induce tuberculin reactivity and scar formation in neonates compared to the WHO International Reference Preparation of BCG (IRP vaccine), and to study the effect of dose and of age at vaccination. DESIGN: A randomized four-armed study: 1) normal dose, 0.05 ml Danish vaccine given to neonates at birth, 2) half the normal dose of Danish vaccine given at birth, 3) IRP vaccine given at birth at normal infant dose, and 4) the normal infant dose of Danish vaccine given at 3 months of age. RESULTS: Larger tuberculin reactions, as well as an increased frequency and larger scars, were seen when Danish vaccine was given at 3 months of age in comparison to neonatal vaccination. Halving the dose resulted in smaller reactions, but the difference was not significant. The IRP vaccine resulted in borderline significantly larger reactions in comparison to the Danish vaccine. The number of infants receiving very early vaccination (0-2 days) was not evenly distributed in all groups, however, which is believed to explain the observed difference.

Allergic mucocutaneous reactions to Japanese encephalitis vaccine.

Japanese encephalitis (JE) vaccine has been used in childhood immunization programmes in Asia for many years. Also travellers from other parts of the world have been vaccinated before travelling in Asian countries. Recommendations for the use of JE vaccine are still debated because severe cases of adverse reactions have been reported. In Denmark an inactivated JE vaccine derived from infected mouse brain has been used and 350000 doses have been distributed from the Statens Serum Institut since 1983. In the period 1983-1995, 101 adverse reactions after JE vaccination have been registered including 73 allergic mucocutaneous reactions. These reactions have occurred each year since 1989 with frequencies varying from 1-17 per 10,000 vaccinees. The highest frequencies and the most serious reactions acquiring hospitalization were seen in the period 1989-1992. Three batches (EJN 012, 033 and 048) distributed before 1992 caused the highest number of reactions but all batches delivered in Denmark since 1989 have caused reactions. Therefore, it is still very important to collect information on adverse events as well as information of the risk of acquiring JE infection in order to give sound recommendations to travellers.

[The childhood vaccination program. Background, status and future]. / Børnevaccinationsprogrammet. Baggrund, status og fremtid.

Surveillance of the Danish childhood immunization programme has taken place at Statens Seruminstitut since 1980. A description of the prevalence of the diseases, which are included in the programme, is presented. The Danish childhood immunization programme has for many years been one of the best in the world although it differs markedly from other countries. The polio immunization programme with inactivated polio vaccine given first and then later live attennuated vaccine is probably the optimal polio immunization programme. The childhood immunization programme began in 1943 with free diphtheria vaccination, and tetanus immunization was added in 1949. There was a big polio epidemic in 1952/53 and the polio vaccine was introduced in 1955. All three vaccines have markedly reduced the prevalence of these diseases. Pertussis vaccine was introduced in 1961 and measles, mumps and rubella vaccination in 1987. Vaccination against Haemophilus Influenzae type b was introduced with success in 1993. In the future several changes will probably be made in the programme because of the possibility using new combined vaccines.

[Markedly increasing incidence of apoplexy among men. A clinical, epidemiologic study of apoplexy incidence between 1972 and 1990 in the municipality of Frederiksberg]. / Markant stigning i apopleksiincidensen blandt maend. En klinisk, epidemiologisk undersøgelse af apopleksisygdommens incidens mellem 1972 og 1990 i Frederiksberg Kommune.

The purpose of this study was to determine possible temporal changes of stroke incidence in a European community. All cases of first-ever stroke (n = 927) were prospectively recorded in the municipality of Frederiksberg, Denmark, in the two periods 1972-1974 and 1989-1990. Complete case ascertainment was ensured by registration of both hospitalized and nonhospitalized patients. Death certificates were also scrutinized. The annual stroke incidence rate per 1000 increased by 18% from 2.6 in 1972-1974, to 3.1 in 1989-1990 (p < 0.01). This increase was due solely to a 42% increase in men, for whom stroke incidence rose from 2.1 to 3.0 (p < 0.0005). Incidence was unchanged in women, 3.0 and 3.1 respectively. In the second study period 85% had CT or necropsy; 91% had cerebral infarction; 8% had intracerebral haemorrhage and 1% had subarachnoid haemorrhage. In a period when decline in stroke incidence has stopped in USA and has continued in Japan, a marked increase in stroke incidence in European men was observed.

Marked increase of stroke incidence in men between 1972 and 1990 in Frederiksberg, Denmark.

BACKGROUND AND PURPOSE: Stroke incidence declined until the end of the 1970s in the United States, and the decline continued into the 1980s in Japan. The purpose of this study was to determine possible temporal changes of stroke incidence in a European community. METHODS: A prospective stroke registry was established in the community of Frederiksberg (population, approximately 90,000), Denmark, in the two periods 1972-1974 and 1989-1990. All patients suspected of stroke were clinically evaluated by a neurologist. Only patients with first-ever stroke were included. Complete case ascertainment was ensured by registration of both hospitalized and nonhospitalized patients. Death certificates were also scrutinized. RESULTS: A total of 927 patients with first-ever stroke was recorded. The annual stroke incidence rate per 1,000 increased by 18% from 2.6 in 1972-1974 to 3.1 in 1989-1990 (p < 0.01). This increase was due solely to a 42% increase in men, in whom stroke incidence rose from 2.1 to 3.0 (p < 0.0005). Incidence was unchanged in women at 3.0 and 3.1, respectively. The incidence rates from 1972-1974 were age and sex adjusted to the 1990 population. After adjustment to the Danish population, stroke incidence in Denmark was 2.0 for all, 2.3 for men, and 1.9 for women. In the second study period computed tomography or necropsy was performed in 85% of cases; 2.4/1,000 had cerebral infarction; 0.20/1,000 had intracerebral hemorrhage; and 0.02/1,000 had subarachnoid hemorrhage. CONCLUSIONS: In a period when decline in stroke incidence has stopped in the United States and has continued in Japan, a marked increase of stroke incidence in Danish men was observed.

[The AIDS epidemic in Denmark 1980-1990]. / AIDS-epidemien i Danmark 1980-1990.

By 31.12.1990, a total of 726 patients with AIDS were diagnosed and notified including 679 men (94%) and 47 women (6%). The first diagnosis was made in 1980. Since then, an annual increase in the number of notified AIDS patients has been observed although the increase has declined from 1989 to 1990. During the years, homo/bisexual men have constituted a decreasing proportion of the annual number of notified AIDS patients (p less than 0.001): from 87% in 1980-1986 to 72% in 1989-1990. The proportion of heterosexually infected patients and intravenous drug users increased during the period of study from 3% and 0.7%, respectively, during the period 1980-1986 to 11% and 7%, respectively, during the period 1989-1990. The number of women with AIDS also increased during the period and constituted 9% of notified patients in 1990. The figures are, however, limited. AIDS patients have been notified from all counties but 72% of the patients live in the Copenhagen region. During the period 1987-1990, approximately 2/3 of the notified AIDS patients had been recognized as HIV-positive for more than one year before the diagnosis of AIDS was established. A stable proportion of approximately 1/4 were HIV tested for the first time and found positive around the time the diagnosis of AIDS was established.(ABSTRACT TRUNCATED AT 250 WORDS)