No abstract

A widespread outbreak of tularemia in Sweden in 2000 was investigated in a case-control study in which 270 reported cases of tularemia were compared with 438 controls. The outbreak affected parts of Sweden where tularemia had hitherto been rare, and these “emergent” areas were compared with the disease-endemic areas. Multivariate regression analysis showed mosquito bites to be the main risk factor, with an odds ratio (OR) of 8.8. Other risk factors were owning a cat (OR 2.5) and farm work (OR 3.2). Farming was a risk factor only in the disease-endemic area. Swollen lymph nodes and wound infections were more common in the emergent area, while pneumonia was more common in the disease-endemic area. Mosquito bites appear to be important in transmission of tularemia. The association between cat ownership and disease merits further investigation.

Acquired carbapenemases confer extensive antibiotic resistance to Enterobacteriaceae and represent a public health threat. A novel acquired carbapenemase, New Delhi metallo-beta-lactamase 1 (NDM-1), has recently been described in the United Kingdom and Sweden, mostly in patients who had received care on the Indian subcontinent. We conducted a survey among 29 European countries (the European Union Member States, Iceland and Norway) to gather information on the spread of NDM-1-producing Enterobacteriaceae in Europe, on public health responses and on available national guidance on detection, surveillance and control. A total of 77 cases were reported from 13 countries from 2008 to 2010. Klebsiella pneumoniae was the most frequently reported species with 54%. Among 55 cases with recorded travel history, 31 had previously travelled or been admitted to a hospital in India or Pakistan and five had been hospitalised in the Balkan region. Possible nosocomial acquisition accounted for 13 of 77 cases. National guidance on NDM-1 detection was available in 14 countries and on NDM-1 control in 11 countries. In conclusion, NDM-1 is spreading across Europe, where it is frequently linked to a history of healthcare abroad, but also to emerging nosocomial transmission. National guidance in response to the threat of carbapenemase-producing Enterobacteriaceae is available in approximately half of the surveyed European countries. Surveillance of carbapenemase- producing Enterobacteriaceae must be enhanced in Europe and effective control measures identified and implemented.

Case-case comparison is a development of case-control methodology made possible by laboratory typing techniques. These comparisons allow a more restricted but more refined analysis of the association of some exposures with infection. Determination of how exposure to the infectious agent occurred is more efficient and unbiased than in standard case-control studies but general factors determining whether disease occurs after an infectious exposure can not be studied.

Helicobacter pylori (HP) is now generally accepted as the main aetiological agent in chronic active gastritis and peptic ulcer. Infection with HP is widespread, but the routes of transmission are still unclear. Several studies have shown increasing prevalence of antibodies against HP with age. In developing countries, age at peak incidence of seroconversion is probably considerably lower than in developed countries. We performed a cross-sectional study to determine the age at maximum incidence of seroconversion to HP in a high-prevalence country (Ethiopia) and in a low-prevalence country (Sweden). Sera from 242 Ethiopian children, aged 2-14 years and from 295 Swedish children aged 1-15 years were analysed using an enzyme linked immunosorbent assay (ELISA) for detecting immunoglobulin G (IgG) antibodies. In Ethiopia, a comparison was made of a local and a reference strain for preparation of the antigen, but there was little difference in outcome. A comparison between antigen prepared from the reference strain and the pooled antigen used in the Swedish study also showed little difference. The sharpest rise in seroprevalence was found in the age range 2-4 years. Among 4-year-olds, some 60% had already seroconverted, and among 12-year-olds almost 100% had done so. In Sweden, the sharpest rise appeared between the ages of 9 and 10 years. Above 10 years of age seroprevalence was around 20%. Infection with HP is acquired in early childhood in Ethiopia, but somewhat later, although still before the teens, in Sweden. To determine properly the risk factors for infection with HP, possible exposure must be assessed around the age of seroconversion, since seropositivity may remain for a long time but environmental factors may have changed since primary infection.

Evidence of recent or ongoing Campylobacter jejuni infection has been found in approximately one out of every four cases of Guillain-Barré syndrome (GBS). It is increasingly accepted that C. jejuni infection is an important causal factor for GBS. However, the likelihood of GBS' occurring following an episode of C. jejuni gastroenteritis has not been measured. The authors measured the incidence of GBS in a large cohort of persons with laboratory-confirmed C. jejuni infection. Cases of C. jejuni infection were derived from the Swedish national laboratory reporting system for the years 1987--1995. Follow-up for GBS was carried out using the Swedish national hospital inpatient register. Nine cases of GBS were detected in the cohort, which comprised 29,563 cases of C. jejuni infection--a rate of 30.4 per 100,000 (95% confidence interval: 13.9, 57.8). This compares with an expected incidence of 0.3 per 100,000 in a 2-month period in the general population. GBS is an important but rare complication of C. jejuni infection. The risk of developing GBS during the 2 months following a symptomatic episode of C. jejuni infection is approximately 100 times higher than the risk in the general population.

Healthcare workers (HCWs) are at increased risk of contracting infections at work and further transmitting them to colleagues and patients. Immune HCWs would be protected themselves and act as a barrier against the spread of infections and maintain healthcare delivery during outbreaks, but vaccine uptake rates in HCWs have often been low. In order to achieve adequate immunisation rates in HCWs, mandatory vaccination policies are occasionally implemented by healthcare authorities, but such policies have raised considerable controversy. Here we review the background of this debate, analyse arguments for and against mandatory vaccination policies, and consider the principles and virtues of clinical, professional, institutional and public health ethics. We conclude that there is a moral imperative for HCWs to be immune and for healthcare institutions to ensure HCW vaccination, in particular for those working in settings with high-risk groups of patients. If voluntary uptake of vaccination by HCWs is not optimal, patients' welfare, public health and also the HCW's own health interests should outweigh concerns about individual autonomy: fair mandatory vaccination policies for HCWs might be acceptable. Differences in diseases, patient and HCW groups at risk and available vaccines should be taken into consideration when adopting the optimal policy.

confi rmed gastrointestinal infections were reported for 101,855 patients in Sweden. Among patients who had Salmonella infection (n = 34,664), we found an increased risk for aortic aneurysm (standardized incidence ratio [SIR] 6.4, 95% confi dence interval [CI] 3.1-11.8) within 3 months after infection and an elevated risk for ulcerative colitis (SIR 3.2, 95% CI 2.2-4.6) within 1 year after infection. We also found this elevated risk for ulcerative colitis among Campylobacter infections (n = 57,425; SIR 2.8, 95% CI 2.0-3.8). Within 1 year, we found an increased risk for reactive arthritis among patients with Yersinia enteritis (n = 5,133; SIR 47.0, 95% CI 21.5-89.2), Salmonella infection (SIR 18.2, 95% CI 12.0-26.5), and Campylobacter infection (SIR 6.3, 95% CI 3.5-10.4). Acute gastroenteritis is sometimes associated with disease manifestations from several organ systems that may require hospitalization of patients.