Comparative seroepidemiology of diphtheria in six European countries and Israel.

Serological surveys for diphtheria were conducted in six European countries including Czech Republic, Hungary, Ireland, Latvia, Luxembourg, Slovakia and one country outside Europe, Israel. For each country, a nationally representative population sample was collected across the entire age range and was tested for antibodies to diphtheria toxin. Although each national laboratory used its preferred assay, the results were all standardized to those of the in vitro neutralization test and expressed in international units (IU) which allowed comparative analyses to be performed. The results showed that increasing age is related to a gradual increase in seronegative subjects (<0·01 IU/ml of diphtheria antitoxin antibodies). This may reflect waning immunity following childhood vaccination without repeated booster vaccinations in adults. Differences in seronegativity were also found according to gender. In subjects aged 1-19 years, geometric mean titres of antitoxin are clearly related to the different vaccination schedules used in the participating countries. Although clinical disease remains rare, the susceptibility to diphtheria observed in these serosurveys highlights the importance of strengthened surveillance.

Recent trends in gonorrhoea and syphilis epidemiology in Sweden: 2007 to 2011.

Gonorrhoea incidence in Sweden continued to increase during 2007-2011, while for syphilis, there was a very minor decrease, but no clear trend. Gonorrhoea incidence increased most among heterosexually infected men and women while for syphilis, the major burden was among men who have sex with men. Neisseria gonorrhoeae resistance to first-line antimicrobials increased annually. Surveillance of infection and antimicrobial resistance along with continuous analysis are needed, to develop prevention activities to reduce risk behaviours.

Increase in reported gonorrhoea cases in Sweden, 2001 - 2008.

Gonorrhoea is on the rise in Sweden and in many other European countries. The present report describes and evaluates the gonorrhoea trends in Sweden from 2001 to 2008 when an increase of 32% was reported. Up to 86% of the cases were reported in men, with the highest proportion among heterosexually infected men (41-59% during these years). Heterosexually infected men more often acquired gonorrhoea abroad, especially in Thailand, whereas women and men who have sex with men were more likely to acquire the infection within Sweden. The recent increase in gonorrhoea cases in Sweden is most likely due to adoption of more risky sexual behaviour (e.g. an increase in the number of sexual partners and the number of new/casual sexual partners and/or low use of condoms) in the Swedish population. Further research regarding more effective identification and description of sexual transmission chains and sexual networks is needed in order to follow the spread of infection and to recognise more effective interventions to prevent the spread of gonorrhoea and also other sexually transmitted infections.

Syphilis epidemiology in Sweden: re-emergence since 2000 primarily due to spread among men who have sex with men.

Syphilis has re-emerged in western Europe since 2000. Changes in sexual behaviour have facilitated the spread of syphilis especially among men who have sex with men (MSM) and improved surveillance systems and case detection have lead to an increase in the reported numbers of cases. This report describes recent trends (2000-2007) of syphilis in Sweden, where the spread among MSM, particularly in the big cities, has been a major contributor to an increase in cases. Estimated syphilis incidence among MSM was up to twenty-eight times higher than in the general Swedish male population. The most affected age group among males was 25-44 years of age. The majority of infections in men and women through heterosexual contacts were acquired abroad whereas the majority of infections attributed to sex between men were acquired in Sweden. Appropriate prevention activities are needed to reach vulnerable populations in Sweden.

Reasons for the sharp increase of genital chlamydia infections reported in the first months of 2007 in Sweden.

After a continuous increase in the reported chlamydia incidence over the past 10 years in Sweden, the incidence decreased by 2% in 2006. A new genetic variant of Chlamydia trachomatis (nvCT) was discovered in Sweden in October 2006 that could not be detected by some of the commonly used diagnostic tests, which led to underreporting of chlamydia cases. This variant has also been called "swCT" by some authors. After the switch at the end of 2006 to other diagnostic tests that can detect nvCT, the reported incidence rose considerably (75 per 100,000 population) in the beginning of 2007. The objective of this study was to explore alternative explanations for this increase and to propose further action if needed. A data quality check was done in order to exclude double reporting and delayed reporting. To compare the incidence of chlamydia and the proportion of the population that was tested, we divided the Swedish counties into two groups, according to the diagnostic test used. We estimated the chlamydia incidence trend for January and February in the years from 2000 to 2005 by regression model, and predict the chlamydia incidence for the same period in 2006 and 2007. The age and sex distribution of the cases in January and February did not differ between the years 2000 to 2007. The proportion of tested people increased on average by 5% every year. If we assume that the percentage of the population that was tested had been 20% higher in 2007 than in 2006, the incidence predicted by the model for January and February 2007 is exactly the same as the incidence that was actually observed. The change of diagnostic test and an increase in the number of people tested, as well as the increase in the prevalence of CT have probably all contributed to the increased numbers of reported chlamydia cases in January and February 2007. These findings support the need for enhanced prevention campaigns in order to control spread of CT.