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Onno de Zwart

Publications and source records attributed to Onno de Zwart.

5 recordsLinked to original sources
PubMed2005

A new meeting place: chatting on the Internet, e-dating and sexual risk behaviour among Dutch men who have sex with men.

OBJECTIVE: To describe the process of Internet chatting, and subsequent dating and sexual (risk) behaviour among Dutch men who have sex with men (MSM), and to compare the demographic profile of the Internet sample with a traditional Dutch MSM sample. DESIGN: A self-selected anonymous Internet sample. METHODS: Enrolment via a prominent gay chat room. Potential respondents were asked to complete an online questionnaire about chatting and dating, and sexual (risk) behaviour with their last date via chatting (e-date). In 26 days, 5302 questionnaires were returned. Of these, 4984 were evaluated as reliable and were used in the analyses. RESULTS: Eighty-two per cent chatted at least once a week, 88% had ever dated through chatting, and of these 89% had had sex with one or more e-dates. With respect to the last e-date, almost 50% had had anal sex with their last e-date, and 15% reported unprotected anal sex. Especially among HIV-positive men, a high percentage of unprotected anal sex was reported (39%). After correcting for the disclosure of HIV status, this percentage remained twice as high compared with HIV-negative and never-tested men (28 versus 14%). Compared with a traditional MSM sample, the Internet sample was significantly younger, and comprised more non-Dutch and bisexual men, whereas the level of sexual risk behaviour with casual partners was comparable. CONCLUSION: The Internet is a popular new meeting place for MSM, and attracts men with a different demographic profile. The level of risk behaviour warrants that opportunities for interventions on the Internet are explored, with special attention to HIV-positive chatters.

Adolescent↗
PubMed2005

A cluster of acute hepatitis C virus infection among men who have sex with men--results from contact tracing and public health implications.

OBJECTIVE: An acute hepatitis C virus (HCV) infection in an HIV-positive man who had sex with men (MSM) was notified. In the period of his seroconversion he was also diagnosed with a rectal lymphogranuloma venereum (LGV) infection, and was part of a cluster of 15 LGV cases in 2003. Our aim was to investigate HCV transmission and to search for potential spread among sexual contacts and known LGV patients. METHODS: Our case series included the index, two recent contacts, and 14 LGV cases. They were interviewed about parenteral exposure for HCV, history of sexually transmitted diseases(STDs), sexual behaviour and drug use. Laboratory investigations included anti-HCV antibodies, HCV-polymerase chain reaction, and HCV genotyping. RESULTS: Seven out of 17 MSM recently seroconverted for HCV (41%). Three genotypes were found. Parenteral risk factors were excluded. Six out of seven had LGV proctitis coinciding with HCV seroconversion, six (86%) were HIV infected. Unprotected anal contact was practised by both HCV uninfected and infected cases. Unprotected active and passive fisting was reported by all seven HCV infected men, compared with two of nine uninfected men (P = 0.003). Non-intravenous drug use during sexual activities was common among all MSM. Numerous, often anonymous, sexual contacts in various European countries were reported. CONCLUSIONS: A cluster of acute HCV infection is reported among mostly HIV-positive MSM, with multiple partners throughout Europe. Sexual techniques potentially leading to mucosal damage (fisting), concomitant STDs such as LGV and drug use seem facilitating factors for spread. Extensive case finding and partner tracing is advocated as well as targeted prevention messages.

Acute Disease↗
PubMed2005

Acceptability and consequences of screening for chlamydia trachomatis by home-based urine testing.

OBJECTIVE: The objective of this study was to study the acceptability and consequences of home-based chlamydia (CT) screening by Municipal Health Services (MHS) among 15- to 29-year-old participants. STUDY: This study consisted of a cross-section of 156 CT-positives and 600 random sampled CT-negatives after receiving the result of their CT test. RESULTS: Thirty-eight percent of the men and 59% of the women responded. The screening method was well-accepted. Seventy percent (52) of the CT-positives were surprised about their result. Infected women more often than men reported a feeling of being dirty and of anxiety about infertility. Curiosity for the CT result was decisive for participation in 68% and perception of personal risk was poor. The willingness to be tested regularly was determined by present chlamydial infection, young age, multiple lifetime partners, short relationship, and earlier test for chlamydia. CONCLUSIONS: Chlamydia screening organised by MHS is acceptable for future screening. Participants with an elevated risk are interested in screening as long as test kits are easily available. Counseling with focus on effects of CT, especially on women, is essential. Alternative approaches are needed to motivate men and non-Dutch high-risk groups.

Adolescent↗