Use of Home-Based Self-Collected Dried Blood Spots to Test for Syphilis, Human Immunodeficiency Virus, Hepatitis C and B Virus Infections and Measuring Creatinine Concentration.

INTRODUCTION: Home-based self-collected dried blood spot (DBS) sampling could simplify sexual health and preexposure prophylaxis care and reduce sexually transmitted infections (STIs) clinic visits for men who have sex with men (MSM). We compared the performance of DBS to venipuncture collected blood samples to test four STIs and creatinine concentration. METHODS: We invited MSM clients of the Amsterdam STI clinic to participate. Routinely collected peripheral blood was tested for syphilis treponemal antibody, HIV (HIV Ag/Ab), HCV (antibodies), HBV (HBsAg) and creatinine concentration. Participants received a home kit for DBS sampling, a return envelope and a questionnaire to evaluate the acceptability, feasibility and usability of DBS, measured on 5-point Likert scales, 1 representing complete disagreement and 5 complete agreement. We assessed sensitivity and specificity of DBS versus peripheral blood-based testing. RESULTS: In 2020 to 2021, we included 410 participants; 211 (51.5%) returned a completed DBS card, 117 (28.5%) returned a partially filled card and 82 (20.0%) did not return a card. The sensitivity for syphilis was 90.8% and the specificity 84.3%. For both HIV Ag/Ab and HBsAg, the sensitivity and specificity were 100.0%. The sensitivity for HCV antibody was 80.0%, and the specificity was 99.2%. The DBS creatinine concentration was a mean of 5.3 µmol/L higher than in venipuncture obtained plasma. Participants' median willingness to take a future DBS was 4 (interquartile range, 3-5). DISCUSSION: Dried blood spot may be an acceptable method among MSM for STI testing and creatinine follow-up during preexposure prophylaxis use. However, collecting enough blood on DBS cards was a challenge, and sensitivities for syphilis and HCV serology were too low.

Increased clonality among Neisseria gonorrhoeae isolates during the COVID-19 pandemic in Amsterdam, the Netherlands.

Distancing measures during the COVID-19 lockdown led to a temporary decrease of casual sex partners among clients of the Centre for Sexual Health (CSH) in Amsterdam, the Netherlands. We investigated the effect of this change on the genotypic and phenotypic distribution of Neisseria gonorrhoeae (Ng) isolates from CSH patients. From each Ng-positive patient we sequenced one isolate, resulting in 322 isolates which constituted two groups: 181 isolates cultured from 15 January to 29 February 2020 (before the first lockdown) and 141 cultured from 15 May to 30 June 2020 (during the first lockdown). Patient characteristics showed significantly more symptomatic patients and significantly fewer reported sex partners during the lockdown. Phenotypic data showed an increase in low-level azithromycin resistance and ceftriaxone susceptibility during the lockdown, and this remained after the study period. The diversity in sequence types (STs) decreased slightly during the lockdown. A shift occurred from ST 8156 being predominant before lockdown to ST 9362 during lockdown and a remarkably low median SNP distance of 17 SNPs was found between ST 9362 isolates obtained during lockdown. These findings reflect restricted travel and the change in sexual behaviour of CSH clients during the lockdown, with a potentially increased local transmission of the ST 9362 strain during this period, which led to genotypic and phenotypic changes in the Ng population. This shows that public health measures have far-reaching consequences and should be considered in the surveillance of other infectious diseases.

Treponema pallidum Subspecies Pallidum Intrapatient Homogeneity at Various Body Locations in Men with Infectious Syphilis.

Syphilis, caused by Treponema pallidum subspecies pallidum (TP), is a complex multistage infectious disease. Systematic dissemination occurs within a few hours of transmission. We determined the molecular variation of TP at various body locations and peripheral blood within patients in different stages of syphilis to assess the distribution of TP strains at these locations. We included 162 men who have sex with men (MSM) with syphilis visiting the Sexual Health Center in Amsterdam between 2018 to 2019, who had TP DNA detected in at least one sample type (anal swab, urine sample, peripheral blood, pharyngeal swab, and/or ulcer swab). TP DNA was detected in 287 samples using a qPCR targeting the polA gene. With multilocus sequence typing (TP-MLST) based on partial sequence analysis of three genetic regions (tp0136, tp0548, tp0705), we characterized all TP DNA positive samples. Samples could be typed (119/287) from at least one anatomical location or peripheral blood from 93/162 (57%) patients in the following stages: 48 (52%) primary, 35 (38%) secondary, and 10 (11%) early latent stage syphilis. The TP-MLST type was identical within each of the 12 patients with typed samples at ≥2 different body locations. The most prevalent TP strains were 1.3.1 (39/93, 42%) and 1.1.1 (17/93, 18%) belonging to the SS14 lineage; 80% (74/93) of the patients carried a SS14 lineage TP strain and 20% (19/93) Nichols lineage. The distribution of TP-MLST types did not differ between patients by syphilis stage. We found intrapatient TP strain homogeneity and no TP strain variation between anatomical location or syphilis stages. More early latent samples should be typed and added in future studies to investigate this in more detail. IMPORTANCE Syphilis, caused by Treponema pallidum subspecies pallidum, is a complex multistage infectious disease. Systematic dissemination is known to occur within a few hours of transmission. Despite the effective antibiotic penicillin, syphilis remains prevalent worldwide. Men who have sex with men are disproportionally affected in high income countries like the Netherlands where 96% of the syphilis cases in 2020 were among this population. The inability to in vitro culture T. pallidum directly from patient samples limits whole-genome sequencing efforts. Fortunately, in 2018 a multilocus sequence typing technique was developed for T. pallidum allowing the monitoring of circulating strains. The significance of our research is in the investigation of T. pallidum molecular variation at various body locations and blood within patients in different stages of syphilis in order to assess the distribution of strains at these locations.

Detection of Treponema pallidum DNA During Early Syphilis Stages in Peripheral Blood, Oropharynx, Ano-Rectum and Urine as a Proxy for Transmissibility.

BACKGROUND: Syphilis diagnosis may be challenging, especially in the asymptomatic and early clinical stages. We evaluated the presence of Treponema pallidum DNA (TP-DNA) in various sample types to elucidate transmissibility during various syphilis stages. METHODS: The study was conducted at the Amsterdam Centre for Sexual Health. We included adult men who have sex with men (MSM), who were suspected of having syphilis. The 2020 European guidelines definitions were followed for the diagnosis and staging of syphilis. Using a polymerase chain reaction (PCR) targeting the polA gene of Treponema pallidum (TP-PCR), we tested the following study samples on TP-DNA: peripheral blood, oropharyngeal swab, ano-rectal swab, and urine. RESULTS: From November 2018 to December 2019 we included 293 MSM. Seventy clients had primary syphilis, 73 secondary syphilis, 86 early latent syphilis, 14 late latent syphilis, 23 treated syphilis, and 27 had no syphilis. TP-DNA was detected in at least 1 study sample in 35/70 clients with primary syphilis (2/70 peripheral blood, 7/70 oropharynx, 13/70 ano-rectum, and 24/70 urine); in 62/73 clients with secondary syphilis (15/73 peripheral blood, 47/73 oropharynx, 37/73 ano-rectum, and 26/73 urine); and in 29/86 clients with early latent syphilis (5/86 peripheral blood, 21/86 oropharynx, 11/86 ano-rectum, and 6/86 urine). TP-DNA was not detected in clients with late latent syphilis or treated syphilis, nor in clients without syphilis. CONCLUSIONS: TP-DNA was frequently detected in various sample types in the absence of lesions. This is in line with the high transmission rate of syphilis and opens diagnostic opportunities for early presymptomatic syphilis stages.

Effects of an over-the-counter lactic-acid containing intra-vaginal douching product on the vaginal microbiota.

BACKGROUND: Over-the-counter intra-vaginal lactic-acid containing douches are marketed as vaginal hygiene products that support optimal vaginal pH balance. We report the effect of a commercially available douche (Etos®) on the vaginal microbiota (VM) in a prospective study. RESULTS: Twenty-five healthy women were recruited through advertisements in 2015-2017 (ethical approval: METC-2014_413) and followed over three menstrual cycles. The participants had a median age of 24 years [IQR: 22-29], were mostly Dutch-Caucasian (88%), and 60% used combined oral contraceptives. All participants douched three times a week during the second cycle, starting on the first day of that cycle. Participants completed a questionnaire at baseline, kept a daily diary to report douching, menses, and sexual activity, self-collected vaginal swabs every other day during the first and third cycle and daily during the second cycle, and measured vaginal pH mid-cycle. A median of 44 vaginal swabs [inter-quartile range (IQR): 41-50] were assessed per participant by 16S rRNA gene (V3-V4 region) sequencing and a Candida albicans PCR was done at four time-points. At baseline, 21 participants (84%) had Lactobacillus-dominated VM (Lactobacillus crispatus (n = 14), L. iners (n = 6), or diverse Lactobacillus species (n = 1) and 4 participants (16%) had VM consisting of diverse anaerobes. In multinomial logistic regression models, a trend towards increased odds were observed for having diverse anaerobic VM in the second and third cycle, compared to the first cycle, after adjusting for menses [odds ratio (OR) = 1.4 (95% CI: 0.9-2.1) and OR = 1.7 (95% CI: 0.9-3.1), respectively] (p = 0.376). Douching did not affect vaginal pH. Menses increased the odds for having VM consisting of diverse anaerobes almost two-fold (OR = 1.7; 95% CI: 1.0-2.8), while douching during menses increased the odds 2.6 fold (OR = 2.6; 95% CI: 1.0-6.5), compared to not menstruating (p = 0.099). Participants were more likely to test positive for C. albicans after cycle 2, compared to cycle 1 [OR = 3.0 (95% CI: 1.2-7.2); p = 0.017]. CONCLUSION: The Etos® douche did not significantly affect the vaginal pH or VM composition, although increased odds for having diverse anaerobic VM was observed, especially when douching during menses. Furthermore, douching may promote C. albicans infections.

Hepatitis E virus seroprevalence and determinants in various study populations in the Netherlands.

BACKGROUND: The epidemiology of hepatitis E virus (HEV) is not fully understood. In this study, we assessed putative risk factors for HEV seropositivity in various study populations in the Netherlands. METHODS: Data and samples from five different study populations were analysed: (A) blood donors (n = 5,239), (B) adults reporting a vegetarian life style since the age of 12 years (n = 231), (C) residents of Amsterdam, the Netherlands, with different ethnic backgrounds (n = 1,198), (D) men who have sex with men (MSM) (HIV positive and HIV negative) (n = 197), and (E) persons who use drugs (PWUD) (HIV positive and HIV negative) (n = 200). Anti-HEV immunoglobulin M (IgM) and immunoglobulin G (IgG) testing was performed using ELISA test (Wantai). RESULTS: HEV IgM seroprevalence was low across all study populations (<1% to 8%). The age and gender-adjusted HEV IgG seroprevalence was 24% among blood donors (reference group) and 9% among the vegetarian group (adjusted Relative Risk [aRR]:0.36, 95%CI:0.23-0.57). Among participants of different ethnic backgrounds, the adjusted HEV IgG seroprevalence was 16% among participants with a Dutch origin (aRR:0.64, 95%CI:0.40-1.02), 2% among South-Asian Surinamese (aRR:0.07, 95%CI:0.02-0.29), 3% among African Surinamese (aRR:0.11, 95%CI:0.04-0.34), 34% among Ghanaian (aRR:1.53, 95%CI:1.15-2.03), 19% among Moroccan (aRR:0.75, 95%CI:0.49-1.14), and 5% among Turkish (aRR:0.18, 95%CI:0.08-0.44) origin participants. First generation Moroccans had a higher risk for being IgG HEV seropositive compared to second generation Moroccan migrants. The statistical power to perform these analyses in the other ethnic groups was too low. In the MSM group the IgG HEV seroprevalence was 24% (aRR:0.99, 95%CI:0.76-1.29), and among PWUD it was 28% (aRR:1.19, 95%CI:0.90-1.58). The number of sexual partners in the preceding six months was not significantly associated with IgG HEV seropositivity in MSM. The association between HIV status and HEV seropositivity was significant in PWUD, yet absent in MSM. HIV viral load and CD4 cell count were not associated with HEV seropositivity in HIV positive MSM and PWUD. CONCLUSIONS: Vegetarians were significantly less often HEV seropositive. Ethnic origin influenced the risk for being IgG HEV seropositive. MSM and PWUD were not at higher risk for being IgG HEV seropositive than blood donors.

Seroprevalence of hepatitis E virus differs in Dutch and first generation migrant populations in Amsterdam, the Netherlands: a cross-sectional study.

BACKGROUND: In the last decade hepatitis E virus (HEV) is increasingly recognized as a cause of acute viral hepatitis in developed countries. HEV is transmitted via the fecal-oral route. In countries like the Netherlands, HEV infection is suspected to be a zoonosis but HEV may also be introduced by migrants. We studied the seroprevalence of HEV among different migrants, mainly Moroccans and Turks, and compared this to that of the native Dutch population in Amsterdam, the Netherlands. METHODS: Data were obtained from a cross-sectional survey of the adult Amsterdam population performed in 2004; the Amsterdam Health Monitor. A total of 1199 plasma samples were tested for IgG-and IgM antibodies to HEV using the Wantai kit according to instructions of the manufacturer. Basic demographic data (gender, age, country of birth, and age at immigration) were used in the analyses. Hepatitis A virus (HAV) serology data were available from a previous study. RESULTS: The total weighted anti-HEV IgG seroprevalence in the overall Amsterdam population was 26.7 %, based on 1199 samples. In the study population (not-weighted) this HEV seroprevalence was 157/426 (36.9 %) for the Dutch participants and it was 161/257 (62.6 %) for Moroccans, 99/296 (33.4 %) for Turks and 42/220 (19.1 %) for other ethnicities. HEV seroprevalence increased significantly with age. First-generation Moroccan migrants (44.0 %) had a significantly higher weighted HEV seroprevalence than the Dutch participants (29.7 %). In the first generation Turks (20.3 %) and first generation migrants from other countries (16.7 %) this weighted seroprevalence was lower, but this was only significant for the 'other ethnicities'. The median age of migration was significantly higher in the Moroccan and Turkish migrants who were HEV IgG positive versus HEV IgG negative. However, when stratifying for age at time of study, median migration age was only significantly different for HEV sero-status for younger Turks and younger 'other ethnicities'. HEV IgM antibodies were found in 0.6 % (n = 7) of participants and none were positive for HEV RNA, showing that there were no acute infections. Despite the common route of fecal-oral transmission for both viruses, there was no relation between HEV and HAV seropositivity. CONCLUSION: Within the multi-ethnical capital city of Amsterdam the HEV seroprevalence in first generation migrant populations differed from each other and from the autochthonous Dutch population. The relation between being HEV seropositive and a higher median age of migration suggests that younger migrants got more often infected in their country of origin than in the Netherlands.

Multilocus sequence typing of Trichomonas vaginalis clinical samples from Amsterdam, the Netherlands.

OBJECTIVES: In this cross-sectional epidemiological study we aimed to identify molecular profiles for Trichomonas vaginalis and to determine how these molecular profiles were related to patient demographic and clinical characteristics. SETTING: Molecular typing methods previously identified two genetically distinct subpopulations for T. vaginalis; however, few molecular epidemiological studies have been performed. We now increased the sensitivity of a previously described multilocus sequence typing (MLST) tool for T. vaginalis by using nested PCR. This enabled the typing of direct patient samples. PARTICIPANTS: From January to December 2014, we collected all T. vaginalis positive samples as detected by routine laboratory testing. Samples from patients either came from general practitioners offices or from the sexually transmitted infections (STI) clinic in Amsterdam. Epidemiological data for the STI clinic patients were retrieved from electronic patient files. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was the success rate of genotyping direct T. vaginalis positive samples. The secondary outcome was the relation between T. vaginalis genotypes and risk factors for STI. RESULTS: All 7 MLST loci were successfully typed for 71/87 clinical samples. The 71 typed samples came from 69 patients, the majority of whom were women (n=62; 90%) and half (n=34; 49%) were STI clinic patients. Samples segregated into a two population structure for T. vaginalis representing genotypes I and II. Genotype I was most common (n=40; 59.7%). STI clinic patients infected with genotype II reported more sexual partners in the preceding 6 months than patients infected with genotype I (p=0.028). No other associations for gender, age, ethnicity, urogenital discharge or co-occurring STIs with T. vaginalis genotype were found. CONCLUSIONS: MLST with nested PCR is a sensitive typing method that allows typing of direct (uncultured) patient material. Genotype II is possibly more prevalent in high-risk sexual networks.

Vaginal high-risk human papillomavirus infection in a cross-sectional study among women of six different ethnicities in Amsterdam, the Netherlands: the HELIUS study.

OBJECTIVE: In the Netherlands the incidence of cervical cancer is higher among ethnic minority populations compared with the general Dutch population. We investigated the prevalence of, and risk factors associated with, vaginal high-risk human papillomavirus (hrHPV) infection in women of six different ethnicities living in Amsterdam. METHODS: For this cross-sectional study we selected women aged 18-34 years old of six ethnicities from the large-scale multiethnic HEalthy LIfe in an Urban Setting study. Self-collected vaginal swabs were tested for HPV DNA and genotyped using a highly sensitive PCR and reverse line blot assay (short PCR fragment (SPF)10-PCR DNA enzyme immunoassay/LiPA25-system version-1, delft diagnostic laboratory (DDL)). Participants completed a questionnaire regarding demographics and sexual behaviour. Logistic regression using generalised estimating equations was used to assess risk factors of hrHPV, and to investigate whether prevalence of hrHPV differed among ethnicities. RESULTS: The study population consisted of 592 women with a median age of 27 (IQR: 23-31) years. Dutch and African Surinamese women reported the highest sexual risk behaviour. HrHPV prevalence was highest in the Dutch (40%) followed by the African Surinamese (32%), Turkish (29%), Ghanaian (26%), Moroccan (26%) and South-Asian Surinamese (18%). When correcting for sexual risk behaviour, the odds to be hrHPV-positive were similar for all non-Dutch groups when compared with that of the Dutch group. CONCLUSIONS: We found an overall higher hrHPV prevalence and higher sexual risk behaviour in the native Dutch population. Further research is needed to unravel the complex problem concerning cervical cancer disparities, such as differences in participation in the cervical cancer screening programme, or differences in clearance and persistence of hrHPV.

Trichomonas vaginalis and Mycoplasma genitalium: age-specific prevalence and disease burden in men attending a sexually transmitted infections clinic in Amsterdam, the Netherlands.

BACKGROUND: Men are not routinely tested for Trichomonas vaginalis (TV) and Mycoplasma genitalium (MG) in the Netherlands and, therefore, very few studies have looked into their prevalence and/or role in urogenital complaints in the Dutch male population. OBJECTIVE: To describe the age-specific prevalence and disease burden of TV and MG, and their co-occurrence with Chlamydia trachomatis (CT), in men attending the sexually transmitted infections (STI) clinic in Amsterdam, the Netherlands. METHODS: Urine samples and clinical data were collected from 526 men who have sex with women (MSW) and 678 men who have sex with men (MSM) attending the STI clinic. To investigate age as a risk factor, we oversampled older men. Urine samples were tested for TV and MG using molecular tests. RESULTS: The overall prevalence was 0.5% (6/1204) for TV and 3.1% (37/1204) for MG. Four out of the six TV cases were older than 40 years and all TV cases were MSW. No age trend was observed for MG, nor did MG prevalence differ between MSW and MSM. Co-infections between TV or MG and CT were rare. TV infection did not associate with urogenital symptoms, whereas 5.9% of men reporting urogenital symptoms were infected with MG. CONCLUSIONS: TV infection was rare in men, asymptomatic and was limited to the heterosexual network. MG infection was relatively common and equally prevalent among MSW and MSM of all ages. Most MG infections remained asymptomatic, however, our results suggest that up to 6% of urogenital complaints could be explained by MG infection.

Protocols for detection and typing of Treponema pallidum using PCR methods.

Syphilis, caused by Treponema pallidum, is a sexually transmitted disease which was epidemic in Europe between the 15th and 20th century. From 2000 onwards it is worldwide mostly encountered among men who have sex with men but also among women in resource poor setting. Syphilis can easily be treated with penicillin but can become chronic, if left untreated. The disease develops in several stages with ulcerative lesions in the primary stage, and systemic spread to organs via the blood in later stages. Taking swab samples from these ulcerative lesions gives the best options for detection by PCR of T. palillidum. Alternatively blood samples can be analyzed in later stages. If tested positive in screening PCR assays, T. pallidum can also be typed by molecular methods, enabling molecular epidemiology. Different protocols are discussed in this chapter, that include all steps from sample collection, nucleic acid extraction, PCR, and detection. The combination of all steps together determine the final sensitivity and specificity of T. pallidum PCR.

Comparison of three genotyping methods to identify Chlamydia trachomatis genotypes in positive men and women.

Chlamydia trachomatis (Ct) comprises 3 serogroups and 19 serovars. Different genotyping methods are available to differentiate between the serovars. The aim of this study was to evaluate the sensitivity and discriminatory power of three genotyping methods, respectively Omp1 sequencing, the Ct Detection and genoTyping (DT) assay and the pmpH real-time PCR discriminating an LGV infection from a non-LGV infection. In total, 50 Aptima Combo 2 (AC2) Ct positive samples were selected and tested with the 3 genotyping methods. The Ct-DT assay detected 3 double Ct infections that caused a non interpretable result by Omp1 sequencing, while Omp1 sequencing has a higher discriminatory power that gave additional information about Ct genovariants. All three methods detected the 6 LGV samples. Although the pmpH real-time PCR detected all LGV infections, a substantial amount (24%) of non-LGV infections were missed. The sensitivity compared to AC2 Ct detection was 80% (95% CI 67-89%) for the Ct-DT assay, 72% (95% CI 58-83%) for Omp1 sequencing and 64% (95% CI 50-76%) for the pmpH real-time PCR. In conclusion, the Ct-DT assay is appropriate for serovar distribution studies, epidemiological studies and differentiation between an LGV and non-LGV Ct infection, while Omp1 sequencing is more appropriate for phylogenetic studies. The pmpH real-time PCR is suitable as second assay to differentiate between an LGV and non-LGV infection, but not as primary detection assay, due to its low sensitivity for non-LGV strains.

Clinical value of Treponema pallidum real-time PCR for diagnosis of syphilis.

The diagnosis of syphilis can be complicated when it is based on diverse clinical manifestations, dark-field microscopy, and serology. In the present study, therefore, we examined the additional clinical value of a Treponema pallidum real-time TaqMan PCR for the detection of primary and secondary syphilis. The additional value of the T. pallidum real-time PCR for the diagnosis of primary syphilis was evaluated by the use of three different algorithms: (i) a head-to-head comparison of the dark-field microscopy result and the T. pallidum real-time PCR result, (ii) comparison of the clinical diagnosis made in a sexually transmitted infection clinic (STI) (including by dark-field microscopy) and the T. pallidum real-time PCR result, and (iii) comparison of the clinical diagnosis made in a general practitioner's office (without dark-field microscopy) and the T. pallidum real-time PCR result. A fourth algorithm was used to determine the performance of the T. pallidum real-time PCR regarding the detection of secondary syphilis. From December 2006 to April 2008, 716 patients with suspected cases of primary syphilis and 133 patients with suspected cases of secondary syphilis were included in the study. A kappa value of 0.601 was found for the agreement between dark-field microscopy and the T. pallidum real-time PCR. Good agreement was found between the T. pallidum real-time PCR and both the diagnosis of the general practitioner (kappa = 0.745) and the diagnosis of the STI clinic (kappa = 0.769). The sensitivity with respect to the STI clinic diagnosis was 72.8%, the specificity was 95.5%, the positive predictive value was 89.2%, and the negative predictive value was 95.0%. The T. pallidum real-time PCR is a fast, efficient, and reliable test for the diagnosis of primary syphilis in an STI outpatient clinic and a general practitioner setting, but it has no added diagnostic value for the diagnosis of secondary syphilis.

Ongoing transmission of a single hepatitis B virus strain among men having sex with men in Amsterdam.

For the past decade, a specific hepatitis B virus (HBV) genotype A strain has been prevalent among men having sex with men (MSM) in Amsterdam, the Netherlands. At what point in time this strain was introduced in the MSM population, and why only this specific strain continues to be transmitted, remains unclear. Between 1984 and 2003, sera of 1862 MSM were retrospectively screened for anti-HBc in the context of the Amsterdam Cohort studies. After 2003, most MSM participating in this study were vaccinated, making further testing less useful. HBV DNA from anti-HBc seroconverters was amplified and sequenced. Poisson regression was used to test for temporal trends in HBV and HIV incidence. Of the 1042 MSM who were negative for anti-HBc at entry, 64 had seroconverted during follow-up at a median age of 32. At the point of seroconversion, 31 MSM were HIV positive. HBV incidence declined dramatically in the first years and then remained stable throughout the study period. The HBV and HIV incidence ran almost in parallel. With the exception of three MSM, all were infected with genotype A. Fifteen of these (41%) were infected with an identical genotype A strain. For the past two decades, an identical genotype A strain has been circulating among MSM in the Netherlands. Although HBV is generally considered more infectious than HIV, this study shows that the trend and magnitude in HBV and HIV incidence among MSM are similar.

Hepatitis B vaccination targeted at behavioural risk groups in the Netherlands: does it work?

In November 2002, the Netherlands adopted a vaccination program targeted at behavioural risk groups. Between January 2003 and December 2007, 1386 patients acutely infected with HBV were reported. Reported cases declined from 326 in 2003 to 220 in 2007. Sexual intercourse was the most frequently reported mode of transmission (65%), especially among men having sex with men. Genotypes A and D remained predominant. In total, 40,600 participants were fully vaccinated, the overall compliance was 62%, and the estimated overall program coverage was 12% of the at-risk population. With more effort, more susceptibles may be reached, but the program will not be sufficient to substantially reduce HBV in the Netherlands. Therefore, universal vaccination should be considered.

TprK gene regions are not suitable for epidemiological syphilis typing.

Given reports of increasing syphilis incidence in Western countries, we used molecular typing and epidemiological data to elucidate Treponema pallidum transmission networks. Samples and data were collected, dating from 2002 to 2005, from a well-defined population of patients with an ulcus and a diagnosis of infectious syphilis. Molecular typing using the tprK gene (V3-V5 region) was performed on 211 isolates from 205 Amsterdam STI clinic patients. We revealed 32 T. pallidum clusters and recognized ten large clusters, consisting predominantly of homosexual men (89%). Yet, no common patient characteristics were found to link the patients in these clusters. We therefore conclude that the highly variable tprK region (V3-V5) is not suitable for elucidating T. pallidum transmission networks in a high risk population.

[Hepatitis B virus transmission patterns in the Netherlands, 2004]. / Transmissiepatronen van hepatitis B-virus in Nederland, 2004.

OBJECTIVE: To gain insight into hepatitis B virus (HBV) transmission in the Netherlands. DESIGN: Descriptive. METHOD: During 2004, epidemiological data and blood samples (if available) were collected for all reported cases of acute HBV infections in the Netherlands. Following DNA isolation and amplification a 648 base pairs fragment of the HBV S gene was sequenced and subjected to phylogenetic analysis. The sequencing details were also linked to epidemiological information. RESULTS: In 2004, 291 cases ofacute HBV infections were reported. Blood samples were received from 171 patients (59%), and the genotype could be determined for 158 patients (54%). 6 genotypes were identified: A (64%), B (3%), C (3%), D (21%), E (5%) and F (4%). Of all patients with genotype A, 52% had been infected via homosexual or bisexual contact and 16% via heterosexual contact. Of all patients with genotype D, 42% had been infected via heterosexual contact and 15% via homosexual or bisexual contact. The genotype A cluster was extremely homogeneous with many identical sequences, while genotype B-E clusters were more heterogeneous. 4 identical sequences were found within genotype F, but the patients could not be epidemiologically linked. CONCLUSION: Sexual transmission, particularly via homosexual or bisexual contact in men, formed the most important risk factor for acquiring an acute HBV infection. Genotype A was predominant in the Netherlands, especially among homosexual or bisexual men. Most infections within genotype D occurred as a result of heterosexual contact. The results show that there was ongoing transmission of HBV in homosexual or bisexual men, while in heterosexuals more cases of new introduction were seen, possibly via chronic carriers from areas where HBV is endemic.

Molecular epidemiology of acute hepatitis B in the Netherlands in 2004: nationwide survey.

To gain insight into hepatitis B virus (HBV) transmission in the Netherlands, epidemiological data and sera were collected from reported cases of acute HBV infections in the Netherlands in 2004. Cases were classified according to mode of transmission. A fragment of the S-gene of HBV (648 bp) was amplified, sequenced, and subjected to phylogenetic analysis. Of the 291 acute HBV cases reported in 2004, 158 (54%) were available for genotyping. Phylogenetic analysis identified 6 genotypes: A (64%), B (3%), C (3%), D (21%), E (5%) and F (5%). Of HBV infected men having sex with men, 86% were infected with genotype A, accounting for 43% of all patients infected with this genotype. There were only three reported cases of injecting drug use of which one was available for sequencing (genotype A). Unlike the genotype A cluster, sequences within the genotype B-E clusters were heterogenic. Within genotype F, several isolates had identical sequences, but patients could not be epidemiologically linked. Sexual transmission, particularly by men having sex with men was the most important transmission route for HBV. Injecting drug use plays a minor role. Genotype A is predominant in the Netherlands, especially among men having sex with men. In addition to imported strains, there seems to be a pool of related but non-identical strains circulating among chronic carriers in the migrant population, from which occasionally new patients are infected, primarily by heterosexual transmission.

[The molecular epidemiology of hepatitis A in The Netherlands; the usefulness of typing isolated viral strains]. / Moleculaire epidemiologie van hepatitis A in Nederland; het nut van het typeren van geïsoleerde virusstammen.

OBJECTIVE: To investigate the epidemiological links between several outbreaks of hepatitis A in The Netherlands (2001-2004). DESIGN: Descriptive. METHOD: Blood samples taken in connection with reports of hepatitis A to municipal health centres from 2001-2004, were typed by determining the nucleotide sequence of the VP3-VP1 and the VP1-P2A regions of the genome of the hepatitis A virus (HAV). Genetic distances were represented graphically by means of a phylogenetic tree. RESULTS: The study into the spread of various subtypes of HAV showed a clear link between the HAV-(sub)genotype and risk of transmission: in men that have sex with men only genotype 1A occurred, in travellers to African countries genotype 1B was predominantly seen. CONCLUSION: A database containing various viral strains from people with hepatitis A in The Netherlands could, if kept up to date, be used as an aid in confirming the classical way of tracing sources as well as for the evaluation of preventative measures.