Birgitta de Jong

Effect of regulation and education on reptile-associated salmonellosis.

Import restrictions and public awareness campaigns are effective against this common childhood infection.

Risk of Travel-Associated Typhoid and Paratyphoid Fevers in Various Regions

BACKGROUND Although enteric fever (typhoid and paratyphoid fevers) is a major global public health problem, comparable data on the risks of contracting travel-associated enteric fever in various regions of the world are scarce. METHODS From the Swedish database on notifiable communicable diseases, we retrieved all case records from 1997 to 2003 on typhoid and paratyphoid fevers. The data set was compared with data on travel patterns obtained from a comprehensive travel database with information from interviews with more than 16,000 Swedish residents with recent overnight travel outside Sweden. RESULTS The overall risk of being notified with enteric fever after travel was 0.42 in 100,000 travelers. The highest risk for typhoid fever was seen in travelers from India and neighboring countries (41.7 in 100,000), the Middle East (5.91 in 100,000), and Central Africa (3.33 in 100,000), whereas the risk was comparatively low in East Asia (0.24 in 100,000). Almost the same risk areas stood out for paratyphoid fever: India and neighbors (37.5 in 100,000), the Middle East (3.64 in 100,000), and East Africa (3.33 in 100,000). The epidemiology of paratyphoid fever was considerably affected by a large outbreak of paratyphoid B in a Turkish tourist resort in 1999. The youngest children were at highest risk for typhoid fever (odds ratio 44.2), whereas youths ages 7 to 18 years were at highest risk for paratyphoid fever (odds ratio 9.7). CONCLUSIONS Detailed risk data for enteric fever after travel could form the basis for travel advice. Vaccination against typhoid fever should always be considered for travelers to the Indian subcontinent, the Middle East, and Africa but should not routinely be given to travelers to the Malay Peninsula.

Outbreak of norovirus in Västra Götaland associated with recreational activities at two lakes during August 2004

A large community outbreak of norovirus (NV) gastrointestinal infection occurred in Västra Götaland County, Sweden in August 2004, following attendance at recreational lakes. A frequency age-matched case control study was undertaken of persons who had attended these lakes to identify risk factors. 163 cases and 329 controls were included. Analysis indicates that having water in the mouth while swimming (OR = 4.7; 95% CI 1.1–20.2), attendance at the main swimming area at Delsjön Lake (OR = 25.5; 95% CI 2.5–263.8), taking water home from a fresh water spring near Delsjön lake (OR = 17.3; 95% CI 2.7–110.7) and swimming less than 20 m from shore (OR = 13.4; 95% CI 2.0–90.2) were significant risk factors. The probable vehicle was local contamination of the lake water (especially at the main swimming area). The source of contamination could not be determined

A summary of reported foodborne disease incidents in Sweden, 1992 to 1997.

Reports of foodborne disease incidents in Sweden from 1992 to 1997 are summarized. The results are based on reports from the municipal environmental and public health authorities to the National Food Administration and from medical authorities to the Swedish Institute for Infectious Diseases Control. A total of 555 incidents, of which 84% were outbreaks, were reported, involving 11,076 ill people. In 66% of the incidents, no disease agent was determined. Bacterial agents were implicated in 25% and viruses in 8% of the incidents. Calicivirus was the most reported agent both in terms of incidents and cases. Mixed dishes was the food category most often implicated in outbreaks, and smorgasbord and casserole or stews were the subcategories that caused the most cases. The place of consumption was unknown in 8% of the incidents. In about 60% of the incidents, the implicated food was consumed in commercial food establishments; in approximately 20% of incidents, it was consumed at home. The average annual incidence of reported foodborne disease in Sweden was estimated to be 21 cases per 100,000. The average annual incidence of reported foodborne salmonellosis and campylobacteriosis was estimated to be 2.0 and 0.6 cases per 100,000, respectively. The awareness and motivation to report foodborne diseases need to be improved, but additional sources of information are needed to counteract some of the limitations of reporting discussed in this work.

Emergence of new Salmonella Enteritidis phage types in Europe? Surveillance of infections in returning travellers

BackgroundAmong human Salmonella Enteritidis infections, phage type 4 has been the dominant phage type in most countries in Western Europe during the last years. This is reflected in Salmonella infections among Swedish travellers returning from abroad. However, there are differences in phage type distribution between the countries, and this has also changed over time.MethodsWe used data from the Swedish infectious disease register and the national reference laboratory to describe phage type distribution of Salmonella Enteritidis infections in Swedish travellers from 1997 to 2002, and have compared this with national studies conducted in the countries visited.ResultsInfections among Swedish travellers correlate well with national studies conducted in the countries visited. In 2001 a change in phage type distribution in S. Enteritidis infections among Swedish travellers returning from some countries in southern Europe was observed, and a previously rare phage type (PT 14b) became one of the most commonly diagnosed that year, continuing into 2002 and 2003.ConclusionsSurveillance of infections among returning travellers can be helpful in detecting emerging infections and outbreaks in tourist destinations. The information needs to be communicated rapidly to all affected countries in order to expedite the implementation of appropriate investigations and preventive measures.

Epidemiological explanation of an outbreak of gastro-enteritis in Sweden in the absence of detailed microbiological information

Waterborne gastroenteritis outbreaks have often gone undetected or been incompletely defined in terms of source and extent. Methods which allow detection or clarification of such events are therefore useful. We describe the methods used to detect and investigate such an outbreak. In autumn 1996 high school absence rates and the rate of parents absent from work to care for sick children suggested a health problem in a Swedish town which had a history of unexplained outbreaks of gastrointestinal disease. A systematic sample of 300 households was surveyed by post. Respondents represented 10% of the total population of the town. Questions concerning symptoms and exposures were included. The same questionnaire was used in a nearby town as a control. Sixty four percent of respondents reported an acute gastrointestinal illness during a two month period. Diarrhoea (90%) and abdominal pain (88%) were the most frequent symptoms among the sick. Two percent of those sick sought medical care. Exposures associated with disease were being a member of a large household, young age, and consumption of water from the community water supply. Attack rate showed a dose response relationship with increasing frequency of water consumption. The peak incidence of gastrointestinal illness occurred shortly after raw water quality control data had shown a rise in indicator bacteria. Further analysis, dividing those infected into groups according to when they became ill and whether they were the first member of their household to fall ill, supported the hypothesis of primary cases being infected from the water supply with some secondary person to person spread.

Risk for Travel-associated Legionnaires' Disease, Europe, 2009

Infections increased in a southeastern direction, with highest risk in Greece.

Gastro-enteritis outbreak among Nordic patients with psoriasis in a health centre in Gran Canaria, Spain: a cohort study

BackgroundBetween November 2 and 10, 2002 several patients with psoriasis and personnel staying in the health centre in Gran Canaria, Spain fell ill with diarrhoea, vomiting or both. Patient original came from Norway, Sweden and Finland. The patient group was scheduled to stay until 8 November. A new group of patients were due to arrive from 7 November.MethodsA retrospective cohort study was conducted to assess the extent of the outbreak, to identify the source and mode of transmission and to prevent similar problems in the following group.ResultsAltogether 41% (48/116) of persons staying at the centre fell ill. Norovirus infection was suspected based on clinical presentations and the fact that no bacteria were identified. Kaplan criteria were met. Five persons in this outbreak were hospitalised and the mean duration of diarrhoea was 3 days. The consequences of the illness were more severe compared to many other norovirus outbreaks, possibly because many of the cases suffered from chronic diseases and were treated with drugs reported to affect the immunity (methotrexate or steroids).During the two first days of the outbreak, the attack rate was higher in residents who had consumed dried fruit (adjusted RR = 3.1; 95% CI: 1.4–7.1) and strawberry jam (adjusted RR = 1.9; 95% CI: 0.9–4.1) than those who did not. In the following days, no association was found. The investigation suggests two modes of transmission: a common source for those who fell ill during the two first days of the outbreak and thereafter mainly person to person transmission. This is supported by a lower risk associated with the two food items at the end of the outbreak.ConclusionsWe believe that the food items were contaminated by foodhandlers who reported sick before the outbreak started. Control measures were successfully implemented; food buffets were banned, strict hygiene measures were implemented and sick personnel stayed at home >48 hours after last symptoms.

Around the World in 1,475 Salmonella Geo-serotypes

Most Salmonella serotypes are named after geographic locations; a few others have surprisingly humorous origins.