Effects of population based screening for Chlamydia infections in the Netherlands limited by declining participation rates.

BACKGROUND: A large trial to investigate the effectiveness of population based screening for chlamydia infections was conducted in the Netherlands in 2008-2012. The trial was register based and consisted of four rounds of screening of women and men in the age groups 16-29 years in three regions in the Netherlands. Data were collected on participation rates and positivity rates per round. A modeling study was conducted to project screening effects for various screening strategies into the future. METHODS AND FINDINGS: We used a stochastic network simulation model incorporating partnership formation and dissolution, aging and a sexual life course perspective. Trends in baseline rates of chlamydia testing and treatment were used to describe the epidemiological situation before the start of the screening program. Data on participation rates was used to describe screening uptake in rural and urban areas. Simulations were used to project the effectiveness of screening on chlamydia prevalence for a time period of 10 years. In addition, we tested alternative screening strategies, such as including only women, targeting different age groups, and biennial screening. Screening reduced prevalence by about 1% in the first two screening rounds and leveled off after that. Extrapolating observed participation rates into the future indicated very low participation in the long run. Alternative strategies only marginally changed the effectiveness of screening. Higher participation rates as originally foreseen in the program would have succeeded in reducing chlamydia prevalence to very low levels in the long run. CONCLUSIONS: Decreasing participation rates over time profoundly impact the effectiveness of population based screening for chlamydia infections. Using data from several consecutive rounds of screening in a simulation model enabled us to assess the future effectiveness of screening on prevalence. If participation rates cannot be kept at a sufficient level, the effectiveness of screening on prevalence will remain limited.

High yield of reinfections by home-based automatic rescreening of Chlamydia positives in a large-scale register-based screening programme and determinants of repeat infections.

INTRODUCTION: In a systematic internet-based Chlamydia Screening Implementation Programme in The Netherlands, all chlamydia-positive participants automatically received a testkit after 6 months to facilitate early detection of repeat infections. The authors describe participation in repeat testing and prevalence and determinants of repeat infection during three consecutive annual screening rounds. METHODS: Data collection included information on testkits sent, samples received and results of laboratory tests at time of baseline test and retest; (sexual) behavioural variables and socio-demographic variables were assessed. Chlamydia positives were requested to answer additional questions about treatment and partner notification 10 days after checking their results. RESULTS: Retest rate was 66.3% (2777/4191). Retest chlamydia positivity was 8.8% (242/2756) compared with a chlamydia positivity at first screening test of 4.1%. Chlamydia positivity was significantly higher in younger age groups (14.6% in 16-19 years, 8.5% and 5.5% in 20-24 and 25-29 years; p<0.01); in participants with lower education (15.2% low, 11.1% medium and 5.1% high; p<0.001) and in Surinamese/Antillean (13.1%), Turkish/Moroccan (12.9%) and Sub-Saharan African participants (18.6%; p<0.01). At baseline, 88.7% infected participants had reportedly been treated and treatment of current partner was 80.1%. DISCUSSION: Automated retesting by sending a testkit after 6 months to all chlamydia positives achieved high retest uptake and yielded a positivity rate twice as at baseline and can therefore be recommended as an additional strategy for chlamydia control. The high rate of repeat infections among known risk groups suggests room for improvement in patient case management and in effective risk reduction counselling.

Lymphogranuloma venereum proctitis in men who have sex with men is associated with anal enema use and high-risk behavior.

OBJECTIVES: In the industrialized world, lymphogranuloma venereum proctitis (LGVP) has been reported only in men who have sex with men. Factors responsible for the outbreak remain to be elucidated. GOAL: The goal of the present work was to elucidate risk factors associated with LGVP. STUDY DESIGN: The study design comprised a cross-sectional study including 32 men with LGVP and 93 men without LGVP (22 with gonorrheal proctitis, 30 with a non-LGV chlamydial proctitis, and 41 with proctitis of unknown etiology). Factors associated with LGVP were analyzed by (multinomial) logistic regression. RESULTS: Comparing men with LGVP with men without LGVP, factors significantly associated with higher risk of LGVP in multivariate analyses were as follows: anal enema use [odds ratio (OR): 7.8, 95% confidence interval (CI): 2.6-23.2], having sex on sex parties (OR: 5.7, 95% CI: 1.5-21.8), and having sex with human immunodeficiency virus-positive partners (OR: 3.2, 95% CI: 1.1-9.3). Evaluating the 4 proctitis groups separately in a multinomial logistic regression model, similar associations between anal enema use and LGVP were found. Men with non-LGV chlamydial proctitis showed less risk behavior than men with LGVP. No substantial difference in risk behavior was found, except for attending sex parties, between men with LGVP, and gonorrheal proctitis or proctitis of unknown etiology. CONCLUSIONS: Apart from men with LGVP, men with gonorrheal proctitis or proctitis of unknown etiology exhibit high risk behavior. Enema use seems to play a key role in transmission of LGVP, and needs further investigation.

Molecular epidemiology of Neisseria gonorrhoeae in Amsterdam, The Netherlands, shows distinct heterosexual and homosexual networks.

Molecular typing, added to epidemiological data, can better identify transmission patterns of gonorrhea in Western countries, where the incidence has recently been rising. From September 2002 to September 2003, patients with a laboratory-confirmed diagnosis of gonorrhea at the Clinic for Sexually Transmitted Infections in Amsterdam, The Netherlands, were subjected to a questionnaire pertaining to sexual risk behavior and sexual partners in the 6 months prior to the diagnosis. The Neisseria gonorrhoeae isolates were all genotyped using PCR-restriction fragment length polymorphism of the porin and opacity genes. All patients with a completed questionnaire and genotyped isolates were included in the study. We obtained 885 N. gonorrhoeae isolates from 696 patients that revealed 88 clusters and 46 unique genotypes. Patients infected at multiple anatomical sites with one or more strains and patients infected several times during the study period were shown to pursue high-risk sexual behavior and were considered core groups. There were 11 clusters of > or =20 patients; in seven clusters, 81% to 100% of patients were men who have sex with men (MSM), three clusters contained 87 to 100% heterosexual men and women, and one cluster was formed by equal proportions of MSM and heterosexual male and female patients. However, the various clusters differed in characteristics such as types of coinfections, numbers of sexual partners, Internet use to seek sexual partners, and locations of sexual encounters. Molecular epidemiology of gonococcal isolates in Amsterdam revealed core groups and clusters of MSM and heterosexual patients that probably indicate distinct transmission networks.

The CD14 functional gene polymorphism -260 C>T is not involved in either the susceptibility to Chlamydia trachomatis infection or the development of tubal pathology.

BACKGROUND: The functional polymorphism -260 C>T in the LPS sensing TLR4 co-receptor CD14 gene enhances the transcriptional activity and results in a higher CD14 receptor density. Individuals carrying the T/T genotype also have significantly higher serum levels of soluble CD14. The T allele of this polymorphism has recently been linked to Chlamydia pneumoniae infection. We investigated the role of the CD14 -260 C>T polymorphism in the susceptibility to and severity (defined as subfertility and/or tubal pathology) of C. trachomatis infection in Dutch Caucasian women. METHODS: The different CD14 -260 C>T genotypes were assessed by PCR-based RFLP analysis in three cohorts: 1) A cohort (n = 576) of women attending a STD clinic, 2) a cohort (n = 253) of women with subfertility, and 3) an ethnically matched control cohort (n = 170). The following variables were used in the analysis: In cohort 1 the CT-DNA status, CT IgG serology status, self-reported symptoms and in cohort 2, the CT IgG serology status and the tubal status at laparoscopy. RESULTS: In the control cohort the CC, CT and TT genotype distribution was: 28.2%, 48.2%, and 23.5% respectively. No differences were found in the overall prevalence of CD14 -260 genotypes (28.1%, 50.7%, and 21.2%) in cohort 1 when compared to the control cohort. Also no differences were observed in women with or without CT-DNA, with or without serological CT responses, with or without symptoms, or in combinations of these three variables. In subfertile women with tubal pathology (cohort 2, n = 50) the genotype distribution was 28.0%, 48.0%, and 24.0% and in subfertile women without tubal pathology (n = 203), 27.6%, 49.3% and 23.2%. The genotype distribution was unchanged when CT IgG status was introduced in the analyses. CONCLUSION: The CD14 -260 C>T genotype distributions were identical in all three cohorts, showing that this polymorphism is not involved in the susceptibility to or severity of sequelae of C. trachomatis infection.