HIV testing behaviour among heterosexual migrants in Amsterdam

This cross-sectional study among heterosexual migrant groups in south-eastern Amsterdam, the city area where the largest migrant groups live, provides an insight into HIV testing behaviour in this particular group. Participants were recruited at street locations (May 1997-July 1998) and interviewed using structured questionnaires. They also donated saliva for HIV testing. In total, 705 males and 769 females were included in this study (Afro-Surinamese (45%), Dutch-Antilleans (15%) and West Africans (40%)). Prior HIV testing was reported by 38% of all migrants (556/1479), of which only a minority (28%) had actively requested HIV testing. Multivariate logistic regression showed that not actively requesting HIV testing was more likely among younger (< 23 years) migrants, especially women (ORwomen: 4.79, p < 0.01, ORmen: 1.81, p < 0.05). Furthermore, women without previous STI treatment (OR 2.19, p < 0.05) with Afro-Surinamese ethnicity (OR 2.12, p < 0.05), men without health insurance (OR 2.17, p < 0.05) and with low education (p < 0.01) were also more likely to not actively request HIV testing. Active requests for HIV testing in case of HIV risk should be facilitated by promoting HIV testing and by improving accurate self-assessment of risk for HIV infection, especially among the groups that do not actively request HIV testing. This would increase HIV awareness and provide the opportunity of better medical care earlier in HIV infection.

A persistent problem with scabies in and outside a nursing home in Amsterdam: indications for resistance to lindane and ivermectin

An ongoing outbreak of scabies in and outside a nursing home in Amsterdam is described. Despite standard treatment with lindane and ivermectin, many recurrences were observed which suggested resistance to these drugs. After treatment with 5% permethrine, the patients were finally cured.

A persistent problem with scabies in and outside a nursing home in Amsterdam: indications for resistance to lindane and ivermectin

An ongoing outbreak of scabies in and outside a nursing home in Amsterdam is described. Despite standard treatment with lindane and ivermectin, many recurrences were observed which suggested resistance to these drugs. After treatment with 5% permethrine, the patients were finally cured.

Changes in prevention and outbreak management of Legionnaires’ disease in the Netherlands between two large outbreaks in 1999 and 2006

Binary file ES_Abstracts_Final_ECDC.txt matches

Changes in prevention and outbreak management of Legionnaires disease in the Netherlands between two large outbreaks in 1999 and 2006

We describe an outbreak of Legionnaires' disease in 2006 in Amsterdam, the Netherlands. Comparisons with the outbreak that took place in 1999 are made to evaluate changes in legionella prevention and outbreak management. The 2006 outbreak was caused by a wet cooling tower. Thirty-one patients were reported. The outbreak was detected two days after the first patient was admitted to hospital, and the source was eliminated five days later. The 1999 outbreak was caused by a whirlpool at a flower show, and 188 patients were reported. This outbreak was detected 14 days after the first patient was admitted to hospital, and two days later the source was traced. Since 1999, the awareness of legionellosis among physicians, the availability of a urinary antigen tests and more efficient early warning and communication systems improved the efficiency of legionellosis outbreak management. For prevention, extensive legislation with clear responsibilities has been put in place. For wet cooling towers, however, legislation regarding responsibility and supervision of maintenance needs to be improved.

[Shigellosis, a sexually transmitted disease in homosexual men]

A study of the registered number of Shigella infections in Amsterdam for the period 1997-2001 revealed that in 2001, there was an increase in the number of homosexual patients with oral-anal contacts as source for their infections. All of these infections were caused by subtype Shigella sonnei. The infections were not associated with a specific meeting place for homosexual men. A relationship with an underlying HIV-infection is likely.

[HIV-screening among pregnant women in the region of Amsterdam in 2002]

In 2001, the Municipal Health Service started offering HIV tests to all pregnant women in and around Amsterdam. All midwives and all hospitals but one participated in this HIV screening. In 2002, of the 10,752 pregnant women offered HIV testing 13.6% refused. HIV antibodies were detected in 24 women (0.26%). The HIV prevalence was doubled compared to the prevalence in 1990-1991, but the number of newly HIV-infected pregnant women remained stable (0.1%). The high number of refusals, as a result of which many HIV-infected women might be missed, is alarming. For this reason, in January 2003, the Municipal Health Service started HIV testing by the opting-out approach. Under the opting-out approach, women are notified that an HIV test will be included in the standard test battery, together with tests for hepatitis B and syphilis, unless she explicitly refuses. It is expected that the opting-out approach for HIV screening of pregnant women will be implemented nationwide in 2003.

Evaluation of the hepatitis B antenatal screening and neonatal immunization program in Amsterdam, 1993-1998

In the enhanced antenatal hepatitis B screening and neonatal immunization program in Amsterdam, 691 hepatitis B surface antigen (HBsAg) positive expectant mothers were reported in the period 1993-1998. The coverage of the screening was calculated at 97%. HBsAg-prevalence was high in women from Ghana and South-East Asia, and lowest in Dutch women. Hepatitis B immune globulin (HBIg) was administered within 24h to 95.9% of the neonates; 99.7% completed the vaccination series. About 6 weeks after the third vaccination the titer antiHBs was > or =100 IU/l in 85% of children; in 12% the titers were 10-100 IU/l; 3% had titers <10 IU/l, of whom 3/521 initially had HBsAg. Low birth weight (OR 3.77), being a boy (OR 1.64) and country of origin were predictors of low postvaccination titers. Coordinated by 0.5 full time equivalent (fte) additional staff, the program was relatively cheap and successful.

Cost-effectiveness of partner pharmacotherapy in screening women for asymptomatic infection with Chlamydia Trachomatis

OBJECTIVE

To assess the cost-effectiveness of pharmacotherapy for male partners in screening women for asymptomatic infection with Chlamydia trachomatis (CT).

METHODS AND DATA

A pharmacoeconomic decision analysis model was constructed for the health outcomes of a CT screening program, such as averted cases of pelvic inflammatory disease and infertility (major outcomes). Reinfection in the absence of partner pharmacotherapy was included in the model. Cost-effectiveness from a societal perspective was estimated for prevalence data from a selective opportunistic screening program in Amsterdam. For diagnosis of asymptomatic CT infection a Ligase Chain Reaction (LCR) test on urine was used; for pharmacotherapy of women and partners azithromycin was used. By linking health outcomes with health care costs and productivity losses, averted costs were estimated. Cost-effectiveness was expressed as net costs per major outcome averted.

RESULTS

Partner pharmacotherapy reduces net costs per major outcome averted of the screening program by approximately 50%. Sensitivity analysis indicates significant improvements in cost-effectiveness of the screening program, even when relevant assumptions are varied. Within the broader framework of the screening program, partner pharmacotherapy is a cost-saving activity.

CONCLUSIONS

Inclusion of partner pharmacotherpy provides significant improvements in overall cost-effectiveness of the CT screening program among women aged 15 to 29. Partner pharmacotherapy lowers net costs per major outcome averted to the realm where implementation of the screening program should be considered. Considering the cost-saving potential, male partner pharmacotherapy should be pursued within the broader framework of a CT screening program for women. Reinfection should be included in any future pharmacoeconomic model of CT screening. Further work on this type of model should also be directed to linking cost-effectiveness to epidemiological models for the long-term spread of infectious diseases in populations.

[Screening for asymptomatic Chlamydia trachomatis infection in pregnancy; cost-effectiveness favorable at a minimum prevalence rate of 3% or more]

OBJECTIVE

To estimate the cost-effectiveness of antenatal screening for Chlamydia trachomatis.

DESIGN

Pharmaco-economic model analysis.

METHOD

The risks of C. trachomatis infection during pregnancy and of complications of the infection as well as the cost of screening for complications (pelvic inflammatory disease, chronic pelvic pain, ectopic pregnancy, infertility and neonatal pneumonia) and of treatment were estimated. Assumed were a ligase chain reaction on urine and treatment of identified infected cases with erythromycin or amoxicillin (second choice). Cost-effectiveness was calculated and presented in net direct and indirect costs per major complication averted.

RESULTS

For C. trachomatis prevalences in pregnancy above 4% benefits exceed the costs. For prevalences between 2.82% and 4.00% net costs are positive, but a major complication averted costs less than f 1000.-. Considering sensitivity analysis as well, screening for C. trachomatis at prevalences above 3% costs less than f 1000.-per major complication averted and might even save costs. No recent Dutch data on C. trachomatis prevalence in pregnancy are published however.

CONCLUSION

Given the current information, antenatal C. trachomatis screening can be recommended from a pharmaco-economic perspective if C. trachomatis prevalence in pregnancy is 3% or more.

Strong decline in herpes simplex virus antibodies over time among young homosexual men is associated with changing sexual behavior

The objective of this study was to evaluate whether the change in sexual behavior among homosexual men observed after the start of the acquired immunodeficiency syndrome epidemic resulted in a change in herpes simplex virus (HSV) seroprevalence in this group over time. In a cross-sectional study, the prevalence of herpesvirus types 1 (HSV1) and 2 (HSV2) was determined at study entry in 1984-1985 and 1995-1997 among 532 young (aged < or = 30 years) homosexual men participating in the Amsterdam Cohort Studies on HIV/AIDS. Risk factors for the presence of HSV antibodies, including human immunodeficiency virus infection, were evaluated, and their influence on HSV prevalence over time was assessed. A strong decrease in HSV1 and HSV2 seroprevalence, from 80.6% to 59.0% and from 51.3% to 19.0%, respectively, was observed between the two time periods. This decrease was not markedly influenced by various demographic and socioeconomic factors. After data were controlled for several markers of sexual activity (such as number of sex partners, human immunodeficiency virus infection, and past episode(s) of gonorrhea), it appeared that the decline in HSV seroprevalence was explained by a concurrent decrease in the presence of these markers. The authors conclude that among young homosexual men in this study, the strong decrease in HSV seroprevalence was associated with a concurrent shift in sexual behavior. Furthermore, these data suggest an increasing sexual component in HSV1 transmission over time.

[Shigellosis in Amsterdam, 1991-1998: incidence and results of contact tracing]

OBJECTIVE

To determine the incidence of reported shigellosis in Amsterdam (1991-1998) and the factors related to the secondary attack rate of shigellosis.

DESIGN

Retrospective.

METHODS

From an automated data bank data were collected on all registered shigellosis patients in Amsterdam in the period 1991-1998, and their contacts found by contact tracing.

RESULTS

567 Patients with shigellosis had been reported and a Shigella infection has been diagnosed in 96 of the 983 contacts. The annual incidence decreased statistically significantly from 13 to 8/100.000. 329 males and 334 females were infected. The highest number of cases was found in children from 0-4 years and among adults from 20-34 years. Of the 663 patients 106 (16%) required hospitalization; for children under 7 this proportion was 30% (32/108). Among the contacts (excluding the 14 contacts with the same foreign source and the same first sickness day as the index patient) the secondary attack rate was 8%. Young age, of both the patient and the contact was independently related to a higher secondary attack rate.

CONCLUSION

With contact tracing for shigellosis a large number of secondary infections were found. Given the high infection rate and large number of hospitalisations among children, contact tracing should focus at this young age group.

[Pharmaco-economic evaluation of mandatory HIV-screening in pregnancy; a cost-efficacy analysis in Amsterdam]

OBJECTIVE

To estimate the cost effectiveness of universal screening for HIV of pregnant women in Amsterdam.

DESIGN

Pharmaco-economic model calculation.

METHOD

An estimate was made of the minimal and maximal prevalences of undiagnosed HIV infection during pregnancy for the whole of Amsterdam, based on epidemiological data from observation among pregnant women in two Amsterdam hospitals and one obstetrical practice. The calculation was based on universal screening with an ELISA test. The interventions after screening comprised pharmacotherapy during pregnancy, delivery by caesarean section and breast-milk substitution. The issues of pharmaco-economic analysis were whether or not costs were reduced and net costs per year of life gained; the question was also studied at what lifetime costs of care for HIV infected children the net costs would be nil (costs equal benefits).

RESULTS

Universal HIV screening in Amsterdam required a total investment of about Dfl 300,000.-per annum. In many of the analysed options for HIV screening the financial profits exceeded the investment. Variation of assumptions showed that the net costs of HIV screening under all conditions investigated would remain below Dfl 1,200.-per life year gained.

CONCLUSION

Universal HIV screening of pregnant women in Amsterdam showed a favourable cost effectiveness. The calculations indicated a possibility of reducing costs.

[Opportunistic screening for genital infections with Chlamydia trachomatis among the sexually active population in Amsterdam. III. Cost-effectiveness analysis of screening women and the role of reinfection and partner treatment]

The role of reinfection and the importance of partner treatment were added to a pharmacoeconomic model for the analysis of a GP-based opportunistic screening programme for Chlamydia trachomatis (CT) in sexually active women in Amsterdam. A favourable cost-effectiveness was found for partner treatment. Partner treatment was cost saving and overall net costs per major outcome averted by the screening programme were reduced by 40% or more due to partner treatment. From a pharmacoeconomic point of view partner treatment should be routinely provided in the framework of a CT screening programme for Amsterdam women.

[Opportunistic screening for genital infections with Chlamydia trachomatis among the sexually active population of Amsterdam. Il Over 90% participation and almost 5% prevalence]

OBJECTIVE

To determine in an opportunistic screening programme for Chlamydia trachomatis (CT) the participation and the CT prevalence among the heterosexual population.

METHODS

Heterosexually active men and women, 15-40 years old, who consulted a general practitioner in Amsterdam, the Netherlands, in the period May 1996-April 1997, without symptoms of a sexually transmitted disease, were asked after informed consent had been given to provide a first-voided urine sample and a few sociodemographic data. The urine was investigated for CT by means of a ligase chain reaction. In case of a CT infection, the general practitioner was asked for information on treatment and partner notification.

RESULTS

A total of 3689 persons were eligible for the study of whom 214 (5.8%) refused participation. Men refused more often than women (9.0% and 4.3% respectively). No relation was found with ethnic background or health care insurance (national health cost insurance/private medical insurance). Refusers were somewhat younger than participants (not statistically significant). CT was diagnosed in 4.9% (95% confidence interval (95% CI): 4.1-5.9) of the women and in 4.7% (95% CI: 3.6-6.1) of the men. In women a decreasing trend was seen in the prevalence of CT with an increase in age: from 13.4% in the group 15-19 years old to 2.3% in the group 35-40 years old. Independent of age a higher prevalence was found in Surinam Creole women. In 83% of the CT patients the general practitioner spoke with the patient about partner notification; usually there was one partner.

CONCLUSION

There was a high participation rate (94%) in this opportunistic screening programme in which urine was tested for presence of CT. The CT prevalence in this asymptomatic population was almost 5%, but it was significantly higher in young women and women from Surinam. It is proposed to start such a screening programme in all general practices in Amsterdam.

[Opportunistic screening for genital infections with Chlamydia trachomatis in sexually active population of Amsterdam. II. Cost-effectiveness analysis of screening women]

OBJECTIVE

To estimate the cost effectiveness of Chlamydia trachomatis (CT) screening of young women visiting general practitioners.

DESIGN

Economic model analysis.

METHODS

Data on the health care needs for CT complications were derived from various sources; costing was done using estimated cost prices, charges and the friction cost method; epidemiological data were derived from a pilot study among 22 general practices in Amsterdam, the Netherlands. The analyses were carried out assuming screening with ligase chain reaction test of a urine sample and treatment of identified cases of infection with single-dose azitromycin. The model intervention consisted of screening all heterosexually active women aged 15-19, 15-24, 15-29, or 15-34 years (strategies 1, 2, 3 and 4, respectively). Cost effectiveness was presented in net direct and indirect costs per woman cured and per major outcome averted (pelvic inflammatory disease (PID), chronic pelvic pain, ectopic pregnancy, infertility and pneumonia of newborns).

RESULTS

The first two strategies were cost saving. For the third strategy net costs per woman cured and per major outcome averted were almost 110.- Dutch guilders (DFL) and over DFL 300, respectively. The last strategy costs over DFL 320 per woman cured and over DFL 910 per major outcome averted. The cost effectiveness was sensitive to the assumed probability of progression of CT infection to PID.

CONCLUSION

Universal implementation of the screening programme investigated in Amsterdam for women aged 15-24 years would result in approximately equal savings and costs. Screening of all 15-29-year-old women would require a net investment of DFL 350,000.

[Surveillance of AIDS and HIV infections in Amsterdam, 1997]

Data were collected in Amsterdam in 1997 from the aids surveillance, from the HIV surveillance among pregnant women and visitors of a clinic for sexually transmitted diseases (STD), and from two 'alternative' HIV test sites, using various survey systems. The findings were compared with those of previous years. Aids was diagnosed in 1997 in 123 patients, in 194 in 1996. Of the 354 patients in whom aids was diagnosed in 1993-1997 in a hospital recording additional information, 113 patients (32%) only learned that they had an HIV infection when aids was diagnosed in them. In 1997, out of 225 pregnant women with an increased risk of HIV infection, 10 were HIV seropositive (4.4%); in 1996, this proportion was 3/285 (1.1%). Among those attending STD clinics, HIV infection was observed approximately as frequently as in earlier years: about 1% of heterosexual men and women.

Adhesion molecule expression on skin endothelia in atopic dermatitis: effects of TNF-alpha and IL-4

BACKGROUND

Atopic dermatitis (AD) is characterized by skin infiltrates of leukocytes, such as lymphocytes and eosinophils.

OBJECTIVE

To describe the mechanisms determining this inflammatory process, we have analyzed expression of adhesion molecules and their regulation on skin endothelial cells (ECs).

METHODS

Expression of adhesion molecules on ECs was analyzed by immunohistochemistry by using Ulex europaeus agglutin 1 as a pan-endothelial marker.

RESULTS

Vascular cell adhesion molecule-1 (VCAM-1), E-selectin, and P-selectin were not found in skin of nonatopic individuals, whereas expression of these surface molecules was observed in nonlesional skin of patients with AD and was even more pronounced in lesional skin or after epicutaneous application of aeroallergen. Induction of adhesion molecule expression was examined on both macrovascular ECs from human umbilical cord vein (HUVECs) and human microvascular ECs (HMEC-1) from skin. TNF-alpha very potently upregulated adhesion molecule expression in vitro on both EC cell types. To verify the in vivo relevance of TNF-alpha, we performed TNF-alpha staining in the skin. TNF-alpha was observed in the dermis of nonatopic skin, both in chymase-containing mast cells and CD68+ macrophages. The increase in the number of TNF-alpha-containing cells was concomitant with the increase in adhesion molecule expression in the skin of patients with AD. IL-4 is supposed to be important in atopic diseases because of its IgE- and VCAM-1-inducing properties. However, IL-4 addition failed to induce VCAM-1 expression on HMEC-1, although in the same set of experiments, a clear induction of VCAM-1 expression by IL-4 on HUVECs was demonstrated. Flow cytometry revealed the absence of 11-4 receptor alpha-chains on HMEC-1 and their presence on HUVECs. Immunohistochemistry examination on skin sections showed no binding of the IL-4R alpha-chain antibodies to ECs.

CONCLUSION

We conclude that adhesion molecule expression is increased in the skin of patients with AD. Most probably, this increased expression is not a (direct) effect of IL-4 on skin endothelium, but other cytokines, such as TNF-alpha, might be responsible for this increased adhesion molecule expression. Continuous adhesion molecule expression may facilitate T-cell extravasation in a nonantigen-specific manner, thus explaining the presence of increased T-cell numbers in nonlesional skin of patients with AD.

Prevalence and correlates of herpes simplex virus type 2 infection: evaluation of behavioural risk factors

OBJECTIVE

To examine the prevalence and correlates of infection with herpes simplex virus type 2 (HSV-2) among sexually transmitted disease (STD) clinic attenders, we studied the prevalence of antibodies to HSV-2 and their association with risk behaviour.

METHODS

Data were collected in a cross-sectional study among STD clinic attenders in Amsterdam. Seropositivity for HSV-2 was determined in 1798 serum samples by means of a monoclonal antibody-blocking enzyme-linked immunoassay.

RESULTS

The prevalence of HSV-2 antibodies was higher than expected: 32.3% in a population in which 3% had current genital herpes and 8% gave a history of genital herpes. Of those with HSV-2 antibodies, only 18% had a history of genital herpes. A strong independent association with the presence of HSV-2 antibodies was found for sexual behaviour, more specifically: homosexual orientation, increasing number of years of sexual activity, increasing number of lifetime partners, number of past gonococcal infections, having receptive anal and (or) vaginal contact.

CONCLUSION

The presence of HSV-2 antibodies had a strong association with past sexual behaviour and, for both sexes, with receptive anal intercourse. HSV-2 antibodies may be used as a surrogate marker of sexual risk behaviour in comparing different populations over time.

[HIV infection and risk behaviour among prostitutes in the Amsterdam streetwalkers' district; indications of raised prevalence of HIV among transvestites / transsexuals]

OBJECTIVE

To determine the prevalence of HIV infection and risk behaviour among various groups of streetwalkers in Amsterdam and the extent of overlap between different prostitution networks.

SETTING

The family room project in the streetwalkers' district in Amsterdam, the Netherlands.

METHODS

In November 1996, saliva was taken from 32 female and 25 transsexual/transvestite prostitutes and tested for antibodies against HIV. Besides, prostitutes were interviewed on risk behaviour, history of sexually transmitted diseases and mobility.

RESULTS

Only one of the participants (a female prostitute) had ever injected drugs. None of the female prostitutes, but 6 of the 25 transsexuals/transvestite prostitutes (24%; 95% confidence interval: 7-41) proved seropositive. None of the HIV infected participants was aware of his serostatus. The transsexual/transvestite prostitutes frequently had receptive anal intercourse with their clients. Condom use was high, but most did not use condoms made for anal intercourse. Female prostitutes also reported a high rate of condom use with their clients. Both groups of prostitutes reported few private partners and a low rate of condom use with these partners. According to the transsexual/transvestite prostitutes many of their clients had sexual contacts with women in their private lives. Many prostitutes thought that they shared the same clients in the district.

CONCLUSION

HIV infections occur quite often among transsexual/transvestite prostitutes in the streetwalkers' district in Amsterdam. The risk of further spread HIV infection to their clients (and through them to other heterosexual populations) is present. AIDS education targeted at this group is important. The use of (special) condoms when having anal intercourse in private as well as in prostitution contacts should be emphatically advised.

[Little HIV risk behavior in drug users during detention in Dutch penitentiaries]

OBJECTIVE

To assess levels of HIV risk behaviour in injecting drug users during and immediately following prison terms in the Netherlands.

DESIGN

Descriptive.

SETTING

Municipal Health Service, Amsterdam, the Netherlands.

METHODS

Injecting drug users taking part in a follow-up study on HIV infection were interviewed on injecting drug use and vaginal and anal sexual contact during their last prison term in the 3 years preceding the interview and on injecting drug use in the week following release from prison.

RESULTS

A prison term in the preceding 3 years was reported by 188 (41%) of 463 interviewed drug injectors. The mean age of the 188 was 35.5 years: 146 (78%) were males, 63 (34%) had HIV antibodies, and the mean duration of latest prison term was 3.6 months. Some use of cannabis, heroin, or cocaine in prison was reported by 104 (55%), 69 (37%), and 38 (20%) respectively. Five injectors (3%) reported having injected in prison: in 4 cases once and in 1 case 3 times. No sharing of needles and syringes was reported. Vaginal or anal sex was reported by 2 (1%) of the men and none of the women. Relapse to drug injecting during the week following release from prison was reported by 78/186 (42%) participants, in most cases (34%) on the very day of release.

CONCLUSION

Contrary to findings from other countries, low levels of HIV risk behaviour occur among imprisoned drug injectors in the Netherlands. Although noninjecting drug use in prison is common, drug injecting and the sharing of injecting equipment is rare. There appear to be no grounds for making clean needles and syringes available in Dutch prisons.

HIV prevention in developed countries

HIV prevention in developed countries is marked by impressive successes and dismal failures. The successes point the way to what works; the failures highlight obstacles that must be overcome. Successes include important behavioural changes among gay and bisexual men, antiviral use to prevent vertical transmission, and securing the safety of the blood supply. New strategies are needed to reach the residual of individuals continuing with unsafe practices (a special hazard in high-prevalence areas); to reach young people who are beginning to engage in sexual relations and injection drug use; and to overcome political opposition to prevention strategies.

Large declines in sexual risk behavior with noncommercial partners among heterosexual injection drug users in Amsterdam, 1989-1995

Previous studies among injection drug users have reported small or nonexistent reductions in sexual risk behavior with noncommercial partners, and a large potential for further heterosexual spread of human immunodeficiency virus (HIV) is thought to be present. In the present study, a long-term follow-up and detailed data on sexual behavior were available. Trends were determined using data collected at 5,214 visits of 653 heterosexual injection drug users who participated in the Amsterdam Cohort Study in Amsterdam, the Netherlands between April 1989 and May 1995. Analysis accounted for repeated measurements of one individual and the effect of participation in the study itself. The authors observed a large reduction in sexual risk behavior with noncommercial partners that became apparent only after stratification of trends by knowledge of HIV serostatus. Sex with noncommercial partners and inconsistent condom use both decreased, especially among known HIV-positive individuals. Apart from nonrandom condom use, there also was nonrandom mixing (selective partner choice). Because this was like-with-like mixing, the risk for further sexual transmission of HIV is diminished. In future studies, more detailed information on sexual behavior, mixing, and knowledge of serostatus should be collected. HIV-epidemic modelers should incorporate nonrandom condom use and nonrandom mixing to improve forecasting.

[HIV incidence in a cohort of homosexual men and a cohort of injecting drug users in Amsterdam, 1985-1995]

Since 1984/1985 a cohort of homosexual men (HM; n = 770 initially HIV-seronegative) and one of injecting drug abusers (IDU; n = 675 initially seronegative) are being followed in Amsterdam, in order to assess the HIV epidemic in these high-risk groups. The HIV incidence in HM fell from 7.2/100 person years in 1985 to 1.0 in 1989, due to safer sexual behaviour. In 1990 there was a temporary rise in HIV incidence coinciding with an increase in gonorrhoea and syphilis in homosexual/bisexual men (not in the cohorts) attending a sexually transmitted diseases outpatient clinic. The rise was due to a relapse in unsafe sexual behaviour. After 1990 the HIV incidence dropped again and it remained at 1/100 person years in 1995. In IDU, in whom a reduction was found in both injecting and sexual risk behaviour, the incidence fell from 8.9 in 1986 to 2.0-3.6/100 person years in 1991-1995. In order to follow the future course of the HIV epidemic, it is argued to open the cohorts particularly for young HM and IDU.

Differences in clinical manifestations of genital chlamydial infections related to serovars

OBJECTIVES

To study the association of serovars of Chlamydia trachomatis with clinical manifestations of genital tract infection and socio-demographic characteristics.

METHODS

In 1986-88 the C trachomatis isolates from 159 heterosexual men and 116 women attending a sexually transmitted disease (STD) clinic were collected and typed accordingly. A medical history was recorded, a physical examination took place and samples were taken for laboratory diagnostics.

RESULTS

Serovars E, F and D were the most common for both men (75%) and women (67%). Men infected with serovars of the C-complex had more often a history of STD (p = 0.06). The opposite was demonstrated in women (p = 0.07). In addition, women younger than 18 years at first intercourse were more often infected with C-complex serovars (p = 0.05). For men, the serovars F/G less often produced symptoms of urethral discharge (p = 0.01) than the serovars of the B-complex and C-complex and were less often associated with the presence of 10 or more leukocytes in a Gram-stained smear (p = 0.04).

CONCLUSIONS

In this study, infections with serovars F and G caused less obvious symptoms and signs of inflammation in men; in women no differences were found in the clinical manifestation of infections with different serovars.

Incidence and risk factors for pneumonia in HIV infected and non-infected drug users

OBJECTIVE

To study the incidence and risk factors for pneumonia in a cohort of HIV infected and non-infected drug users (DU).

DESIGN

A prospective epidemiological study.

SETTING AND PATIENTS

Injecting and non-injecting DU who attended the Municipal Health Service in Amsterdam for follow-up visits in the study.

MAIN RESULTS

203 HIV infected and 437 non-infected DU were followed for a total of 1749 person-years. HIV infected DU reported 111 episodes of pneumonia, which required hospitalization in 29 cases, and HIV negative DU reported 55 episodes, which required hospitalization in nine cases. The incidences among HIV positive and HIV negative DU were 0.19 and 0.05 per person-year respectively. With multivariate Poisson regression current injecting (RR 2.13), recent seroconversion (RR 3.92), asthmatic constitution (RR 2.72), CD4+ cell count between 200-500 (RR 1.67 compared to > 500), CD4+ cell count less than 200 (RR 2.23 compared to > 500) and a previous history of pneumonia (RR 2.43) were independently associated with self-reported pneumonia among HIV infected DU. Among HIV negative DU heroin smoking (RR 1.87), asthmatic constitution (RR 3.62) and a previous history of pneumonia (RR 2.84) were independently associated with self-reported pneumonia. Also a higher Quetelet Index (QI) appeared to be protective (QI > or = 21 RR 0.42, QI 19-21 RR 0.82 compared to QI < 19) among HIV negative DU. Risk factors for reported and hospitalized cases of pneumonia were comparable among HIV positive DU.

CONCLUSIONS

HIV infected DU are at increased risk for pneumonia and the rate increases with lower CD4 cell counts. Also behavioural characteristics, such as injecting drug use and smoking heroin, and clinical history variables, such as a history of pneumonia or an asthmatic constitution, are risk factors for pneumonia among DU. Pneumococcal vaccination should not only be focused on HIV positive DU but also on the identified risk groups among HIV negative DU.

Euthanasia and physician-assisted suicide in homosexual men with AIDS

BACKGROUND

In the Netherlands a nationwide study has shown that, in 38% of deaths, there have been medical decisions concerning the end of life (MDEL); 2.1% of all deaths were brought about by euthanasia or physician- assisted suicide (PAS). We investigated the incidence of MDEL in homosexual men with AIDS, suspecting that it might be higher, and studied the effect of euthanasia/PAS on survival time.

METHODS

The patients were 131 male homosexual participants in a cohort study in Amsterdam, diagnosed between 1985 and 1992 as having AIDS; all had died before Jan 1, 1995. Clinical and laboratory data and information on mode of death were obtained from their physicians and by review of hospital records. Those who died by euthanasia/PAS or in whom there had been other MDEL were then compared with those who died naturally.

FINDINGS

29 men (22%) had died by euthanasia/PAS and in 17 (13%) another MDEL had been made; thus, more than one-third of these men had made medical decisions concerning the end of life. The greatest difference between the groups was in age at time of diagnosis-72% aged 40 or more in the euthanasia/PAS group compared with 38% in the natural death group. The likelihood (relative risk) of euthanasia/PAS increased with duration of survival after AIDS diagnosis. Comparison of the groups in terms of three laboratory markers (CD4+ and CD8+ cells and phytohaemagglutinin responses) in the two years before death, and estimates of these markers at the time of death, did not indicate any substantial shortening of life by euthanasia/PAS; in the judgment of the physicians, most of these patients would have died naturally within one month.

INTERPRETATION

A possible reason for the high incidence of MDEL in this cohort was a good knowledge of the characteristics of AIDS acquired through long-term awareness of HIV infection. The higher rate of euthanasia in those with long survival from AIDS diagnosis could reflect either additional suffering or the greater opportunity to discuss this option with friends and physicians. Our findings indicate that euthanasia and other MDEL did little to shorten life; rather, they were an extreme form of palliation, applied in the terminal phase of a lethal disease.

Predictors of mortality in the Amsterdam cohort of human immunodeficiency virus (HIV)-positive and HIV-negative drug users

The impact of human immunodeficiency virus (HIV) infection and other risk factors on mortality was studied in a cohort of Dutch injection drug users and drug users who did not inject. Participants were recruited between 1985 and 1992 and followed up through 1993. Vital status was ascertained through repeat visit information, supplemented by population register data. A total of 77 deaths were recorded among 632 drug users, for a mortality rate per 1,000 person-years of 7 for HIV-negative noninjection drug users, 18 for HIV-negative injection drug users, and 64 for HIV-positive injection drug users. In multivariate analyses, limited to injection drug users, a positive HIV serostatus, age above 40 years, and using benzodiazepines several times daily were significantly associated with an elevated risk of death, both for death from all causes and for death preceding acquired immunodeficiency syndrome (AIDS) diagnosis (pre-AIDS). For pre-AIDS death, the adjusted relative risk associated with HIV infection was 2.2 (95% confidence interval 1.3-3.7). Only 38% of HIV-infected injection drug users who died were diagnosed with AIDS. However, 76% of HIV-infected injection drug users who died without AIDS diagnosis had evidence of immunosuppression (CD4 count < 500/microliters). Daily use of methadone and participation in needle and syringe exchange schemes were not associated with lower mortality rates. This study illustrates in a group of injection drug users with a 30% HIV seroprevalence and a high background mortality the profound influence on mortality that HIV infection has gained.

Development and evaluation of screening strategies for Chlamydia trachomatis infections in an STD clinic

OBJECTIVES

To identify predictors for Chlamydia trachomatis infection among visitors of an STD clinic in Amsterdam in 1986-1988. To design predictor-based screening programmes for C trachomatis. To evaluate the chosen screening strategy in 1993.

METHODS

In 1986-1988, 947 heterosexual men and 648 women participated in the study. A medical history was recorded, a physical examination took place and samples were taken for laboratory diagnostics. Information for 1993 was available from routine databases.

RESULTS

C trachomatis infections in heterosexual men in 1986-1988 (prevalence 15.8%) were independently associated with: age under 26 years, being an STD contact, coitarche below 13, last sexual contact with a non-prostitute, (muco)-purulent urethral discharge and ten or more leukocytes per microscopic field of urethral smear or urine. For women (prevalence 21.5%) independent predictors were age under 26, no history of STD, being an STD contact, cervical friability, (muco)purulent cervical discharge, presence of clue cells and ten or more leukocytes per field of urethral smear. Screening men with one anamnestic predictor for C trachomatis and ten or more leukocytes in smear or urine (59% of men) would detect 93% of the cases in 1986-1988. For females only universal screening proved to be suitable. After the introduction of a screening strategy in 1989 (universal for women, indicated by urethritis for men), a strong decline was found in the C trachomatis prevalence for all subgroups in 1993, excluding prostitute's clients and Turkish men.

CONCLUSIONS

In 1993 the overall C trachomatis prevalence had declined among the attendants of the STD clinic. It seems likely that this fall was caused both by the screening programme and the reduction of risk behaviour.

Validity of self-reported sexually transmitted diseases in a cohort of drug-using prostitutes in Amsterdam: trends from 1986 to 1992

BACKGROUND

Rates of self-reported sexually transmitted diseases (STD) among drug-using prostitutes in Amsterdam have been shown to be declining. However, self reports may provide biased estimates.

METHODS

We determined the prevalence of risk indicators for and time trends in incorrect self-reported STD in a cohort of drug-using prostitutes. Rates of self-reported STD were validated with diagnosed STD from a special STD clinic for drug-using prostitutes.

RESULTS

Between 1986 and 1992, 314 STD were diagnosed in 85 (65%) of 131 studied prostitutes. Overall, 34% of diagnosed STD was not reported in the cohort, referred to as underreporting. For 40% of reported STD, no diagnosis was obtained ('overreporting'). In spite of these misclassifications, absolute numbers of reported and diagnosed STD practically balanced. Underreporting was independently associated with longer residence in Amsterdam (OR = 2.34 per 5 years), more than six clinic visits between two cohort visits (OR = 0.31), daily use of non-parenteral drug (OR = 8.45) and mainly injecting heroin (OR = 6.93); overreporting was independently associated only with a lower frequency of clinic visits. Multivariate analyses showed that trends in underreporting and overreporting were in part explained by a higher number of visits in the cohort and by lower numbers of clinic visits between two cohort visits.

CONCLUSIONS

Self-reporting of STD in our cohort is unreliable and misclassification prevalent; risk factors for and associates of self-reported STD are biased. Inferences drawn from self reports are potentially misleading and therefore such data need to be validated. Trends in misclassification can be interpreted as recall errors and as a study participation effect. For monitoring of STD prevalences in relation to trends in sexual risk behaviours, diagnosed STD should be used in preference to self reports.

[HIV surveillance in an outpatient clinic for sexually transmissible diseases in Amsterdam, 1991-1994; low and stable prevalence among heterosexual clients]

OBJECTIVE

To assess the HIV prevalence among heterosexual attenders of a clinic for sexually transmitted diseases (STD) and among subpopulations, including young gay men and ethnic minorities.

SETTING

Outpatient clinic for sexually transmitted diseases (STD) of the Municipal Health Service of Amsterdam, the Netherlands.

METHODS

Semi-annually in the period 1991-1994, blood samples given voluntarily and anonymously were tested for HIV antibodies and some characteristics were collected of approximately 1000 clinic attenders.

RESULTS

Since 1991, 6766 clinic attenders were eligible for participation, of whom 6200 (92%) were actually tested. The overall HIV prevalence decreased from 3.9% in the first half of 1991 to 2.3% in the second half of 1994. Among heterosexual clinic attenders the prevalence remained stable below 1%, due mainly to visitors from abroad rather than to Dutch heterosexuals: 20 of the 23 HIV infected heterosexuals were not Dutch. None of these 23 seropositive persons knew of their HIV infection, mostly because they had not been tested previously. The HIV prevalence among gay men decreased over the years. In addition, the number of gay male attenders younger than 30 years decreased strongly over time.

CONCLUSIONS

HIV infections among heterosexual STD clinic attenders are relatively few and are seen mainly among non-Dutch. We found no indications of an increase of the HIV prevalence among heterosexual clinic attenders. The results among young gay men are suggestive of a shift towards safer sexual behaviour in this group.

The predictive value of T cell function in vitro and pre-AIDS zidovudine use for survival after AIDS diagnosis in a cohort of homosexual men in Amsterdam

The best independent predictors of survival after AIDS diagnosis were determined in 160 homosexual men from the Amsterdam Cohort Study (1987 CDC case definition). In a Cox model, all pre-AIDS laboratory markers gathered during follow-up in the study did not independently predict survival after AIDS. A second analysis, using data available only at AIDS diagnosis, revealed that T cell reactivity after stimulation with phytohemagglutinin and monoclonal CD3 antibodies and the CD4+ cell count at diagnosis were independent predictors of survival. In an interval-based Cox model, the predictive value of pre-AIDS zidovudine use was determined. One year after AIDS diagnosis, participants with pre-AIDS zidovudine use had a worse survival probability (relative hazard = 3.99). In conclusion, the survival probability of homosexual men with AIDS can be estimate adequately using information obtained at clinical AIDS diagnosis. Analysis revealed the important predictive value of T cell function tests in vitro.

Determinants of penicillinase producing Neisseria gonorrhoeae infections in heterosexuals in Amsterdam

BACKGROUND AND OBJECTIVES

At the STD clinic of the Municipal Health Service in Amsterdam, the annual number of infections with penicillinase-producing Neisseria gonorrhoeae (PPNG) strains remained relatively stable from 1983 until 1990, while the number of non-PPNG infections declined dramatically. To investigate the PPNG and non-PPNG epidemic, a cross sectional study was conducted in 1989 and 1990. The purpose of this study was to assess determinants of PPNG infections among heterosexuals diagnosed with gonorrhoeae.

METHODS

In addition to routinely collected data in new consultations for STDs, information on alcohol use, drug use and sexual behaviour was obtained from patients diagnosed with gonorrhoea. The diagnosis of gonorrhoea was based on a positive culture and isolates were screened for PPNG. Logistic regression analysis was used to assess independent predictors of PPNG infection.

RESULTS

Additional information was available of 328 women and 995 heterosexual men diagnosed with gonorrhoea. PPNG was diagnosed in 86/328 (26%) women and in 329/995 (33%) men. Logistic regression analysis identified a Central/South American nationality (odds ratio(OR) = 2.46) and older age (OR = 1.04 per year) as positively associated with PPNG infection in female patients. An inverse relation was found with use of hard drugs (OR = 0.29). Among men diagnosed with gonorrhoea, sexual contacts with window prostitutes (mainly women from Central/South America) (OR = 1.98) and a foreign nationality (OR = 1.78) were positively associated with PPNG infection, and sexual contact with drug using prostitutes (OR = 0.47) inversely.

CONCLUSIONS

PPNG infections were especially common among Central and South American window prostitutes and their clients, but not among hard-drug addicted prostitutes and their clients. Since window prostitutes originating from Central and South American countries are transient in Amsterdam, prevention activities targeted at these prostitutes and their clients should be continued to limit the spread of PPNG and other STDs within these groups.

Regional distribution and incidence of human papillomavirus infections among heterosexual men and women with multiple sexual partners: a prospective study

OBJECTIVE

To assess prevalence, incidence and potential risk factors of human papillomavirus (HPV) infection among heterosexual men and women with multiple partners and to identify niches of HPV-infection.

DESIGN

A prospective study of heterosexual men and women with multiple partners attending an STD clinic as participants in a study on HIV from May 1988 until January 1991. Routine STD examination and physical examination using colposcopy were performed, interviews with standardised questionnaires were administered. Specimens for HPV DNA detection by polymerase chain reaction were collected from multiple sites of the genital, anorectal and oral regions. In women cervical cytology was performed.

SETTING

The STD Clinic of the Municipal Health Service of Amsterdam.

PARTICIPANTS

162 women and 85 men entered the study, 110 women and 48 men were followed up.

RESULTS

At entry of the study 37 (23%) women and 24 (28%) men were found positive for HPV DNA at any site. Only in one woman was oral presence of HPV DNA found during follow-up. Abnormal cervical cytology was observed in four women. In multivariate analysis, diagnosis of condylomata [odds ratio (OR) 5.61, 95% confidence interval (CI) 1.86 to 16.90)], reporting genital dermatological abnormalities (OR 3.72, 95% CI 1.38 to 9.99) and age (OR per year 0.93, 95% CI 0.88 to 0.99) predicted independently the presence of HPV DNA in women at entry of the study. In women 59 of the 99 (60%) HPV infections were observed in the genital region and 40% in the anorectal region: in men these figures were 65% and 35%, respectively. The incidence of HPV infection was 47.1 and 50.5 per 100 person-years for women and men respectively. At least 20/99 (20%) infections in women were intermediate or long persistent and only 3/48 (6%) HPV infections in men (P = 0.03). No risk factor for persistency could be determined, either in women or in men.

CONCLUSIONS

HPV infection was found to be a multicentric genital and/or anorectal event both in women and men. The oral presence of HPV DNA was detected only once in one of the participants. In women persistent HPV infection was more common than in men. Independent predictors for presence of HPV DNA in women were diagnosis of condylomata acuminata, reporting genital dermatologic abnormalities and age. Incidence of HPV infection in women turned out to be 47.1 infections per 100 person-years and for men 50.5 per 100 person-years.

Risk factors for the transition from noninjection to injection drug use and accompanying AIDS risk behavior in a cohort of drug users

Although injection drug users have been shown to reduce high-risk injection behaviors in response to the epidemic of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS), the total elimination of risk behaviors has not been achieved. A more fundamental preventive measure may be to keep drug users from starting to inject at all. The authors selected 184 drug users from a cohort study in Amsterdam, the Netherlands, from 1985 to 1992, who had reported at entry to the study that they either had never injected drugs or had injected for the last time more than 1 year before the initial visit. Over a 5-year follow-up period, impressively high cumulative rates of transition to injection drug use were found in both groups. Among drug users who had never injected drugs, 30% began injecting; among those who had injected drugs 1-5 years before their entry into the study, 70% started injecting again. These rates were stable over time. The authors also confirmed that new injectors are at high risk of acquisition of HIV infection. With the use of a survival and a nested case-control analysis, the following independent risk factors that increased the likelihood of starting to inject were found: previous injecting history, ethnicity other than Surinamese/Antillean, regular long-term use of cocaine, current use of heroin, and a current steady sexual relationship with a partner who injects drugs. Given the high and stable incidence of initiation of injection among drug users within the cohort study, the prevention of this behavior appears to be difficult. Additional studies are needed to determine effective prevention strategies.

Enzyme immunoassay with enhanced specificity for detection of antibodies to Chlamydia trachomatis

Two different methods for preventing the binding of cross-reacting antibodies to the genus-reactive chlamydial lipopolysaccharide (LPS) were used to improve the specificity of an enzyme immunoassay for the determination of antibodies to Chlamydia trachomatis. Coated elementary bodies were treated with either sodium periodate, to oxidize the antigenic sites of the LPS, or Triton X-100, to extract the LPS. By using these new enzyme immunoassays, the standard enzyme immunoassay, and the whole inclusion fluorescence (WIF) assay, antibodies to C. trachomatis were determined in sera from different groups of patients and controls. Paired serum samples from patients with culture-proven urogenital C. trachomatis infections showed similar responses in all three assays. Paired serum samples from patients with Chlamydia psittaci infections showed similar responses in the WIF assay and the standard enzyme immunoassay, whereas significantly reduced titers were obtained in the enzyme immunoassays with treated antigen, especially in the convalescent-phase serum samples. Serum samples from patients with symptoms suggestive of infection with C. trachomatis, pregnant women, and blood donors were evaluated by all three types of assays. Eighty percent of the significant reductions in immunoglobulin G (IgG), IgA, and IgM titers were observed in sera with WIF assay titers in the lower classes (IgG, 1: < or = 256; IgA, 1: < or = 32; IgM, 1: < or = 16). From these results we conclude that oxidation of the antigen by sodium periodate is a simple and effective method of producing an enzyme immunoassay with enhanced specificity that could be useful for diagnostic purposes and seroepidemiological studies.

[Survival of patients following the diagnosis of AIDS in the Amsterdam region, 1982-1991]

OBJECTIVE

To evaluate the survival of 975 AIDS patients diagnosed in the Amsterdam region between 1982 and 1991, with follow-up until December 31st, 1992.

METHODS

Analysis of data from the active AIDS surveillance system for the Amsterdam region at the Municipal Health Service.

RESULTS

Amsterdam region residents had 1, 2 and 3-year survivals of 69.8%, 42.6% and 21.2%, respectively. The 5-year survival was 7.7%. The median survival probability for all patients showed great improvement, from 9 months in 1982-1985 to 26 months in 1990. For patients initially presenting with only Pneumocystis carinii pneumonia (PCP) the greatest improvement occurred between the period 1982-1985 and the year 1986. For patients without PCP the most important improvement occurred one year later. From 1988 onwards no important improvement in the 1-year survival is noticed. The 2-year survival, however, appears still to be increasing. In a Cox proportional hazards model the following variables were found to be independent predictors for survival: age at diagnosis, earliest clinical AIDS manifestations, year of diagnosis and HIV risk group. No differences were seen in the 1 and 2-year survival probabilities for men and women with AIDS. Heterosexual men and women tended to have a poorer survival than intravenous drug users and homosexual and bisexual men.

CONCLUSION

A noticeable improvement in the survival probability with time occurred for AIDS patients living in the Amsterdam region through the years 1982-1991, although the overall survival after AIDS diagnosis is still poor. The 1-year survival appears to have reached a plateau, the 2-year survival is still increasing. Improved clinical experience, awareness of HIV related complaints in high risk groups, better diagnostic methods and the availability of proper medication (prophylactic and treatment) are the most likely explanations of the improvement in survival.

Do bisexual men play a significant role in the heterosexual spread of HIV?

BACKGROUND AND OBJECTIVES

To assess the potential role of bisexual men in the transmission of HIV to women.

STUDY DESIGN

The study population consisted of homosexual men participating in a longitudinal cohort study on HIV and AIDS in Amsterdam, the Netherlands, which started in 1984. Between April and November 1991, an additional questionnaire was administered concerning sexual behavior with both male and female partners in the last 6 months.

RESULTS

Of these men, 27% described their sexual preference as bisexual or heterosexual. In the last 6 months, 23 (3%) had heterosexual contacts. Vaginal intercourse was the sexual technique most practiced. Anal intercourse with a female partner was rare. Four heterosexual active HIV positive men always used condoms when having heterosexual contact (1 missing). Of the 18 heterosexually active HIV seronegative men, 12 did not use condoms consistently with their female partner(s). Two of these 12 men also had unprotected insertive anogenital intercourse with male partners, which conveys a small transmission risk in the window period in the case of a seroconversion.

CONCLUSION

Widespread transmission of HIV from these homosexual men in this study is not likely. However, the studied men are most probably not representative for homosexual men in Amsterdam, the Netherlands. Further study on the potential role that bisexual men play in the HIV transmission to women is therefore needed.

[HIV infection and unsafe sexual behavior among young homosexual men in Amsterdam, 1992]

OBJECTIVE

To determine the prevalence of sexual behaviour with the risk of HIV transmission among young homosexual men in Amsterdam.

DESIGN

Point prevalence study.

SETTING

Amsterdam.

METHODS

Participants were recruited through advertisements and in gay bars and a STD clinic in the period October 1991-1992. A questionnaire regarding sexual behaviour was completed, and blood samples were drawn to test for presence of serological markers of HIV infection, hepatitis B and syphilis.

RESULTS

Enrolled in the study were 154 men (mean age: 25 years). The prevalence of antibodies against HIV was 5% and that of hepatitis B 22%. Receptive anogenital intercourse with steady partners in the previous six months was reported by 60% (74% sometimes without a condom), with non-steady partners by 41% (40% without a condom). The figures for insertive anogenital intercourse were: steady partners: 45% (74%); non-steady partners: 49% (41%). Overall 43% (66/153) reported at least one unprotected anogenital contact in the previous six months. The presence of HIV antibodies was correlated with the number of partners with whom anogenital sexual intercourse was practised.

CONCLUSION

The HIV prevalence (5%) was relatively low. Considering the high prevalence of unsafe sexual behaviour further spread of HIV infection among young homosexual men is to be expected.

[HIV prevalence among Surinam and Antillean drug users in Amsterdam]

OBJECTIVE

To determine the HIV prevalence and the frequency of injecting drugs among drug users from Surinam and the Netherlands Antilles in Amsterdam.

DESIGN

Descriptive study.

SETTING

Amsterdam streets.

METHOD

Participants were recruited in 1992 in the street and interviewed about their drug use behaviour, sexual life style and previous HIV test results. Blood or saliva samples were collected for HIV antibody testing.

RESULTS

Of 198 participants recruited, 185 (93%) were males. The mean age was 38 years. The mean duration of stay in the Netherlands was 19 years and mean duration of drug use 14 years. Sixty-eight percent of the participants received methadone treatment. Injecting drugs at any time was reported by 29 (15%) participants. Injecting drug users (IDU) more often had a steady partner who also injected or otherwise used drugs. Nearly one-quarter reported having had sex with a steady or casual IDU partner. HIV prevalence among IDU was 17% (5/29; 95%-CI 7.4-35%), among heterosexual male non-IDU 4.5% (7/156; 95%-CI 2.1-9.1%) and among female non-IDU 9.1% (1/11; 95%-CI 1.3-44%). HIV positive heterosexual non-IDU reported a higher mean number of heterosexual partners in the past 6 months (7.1 versus 1.3), more often had had hepatitis and more often were blood transfusion recipients than HIV negative heterosexual non-IDU.

CONCLUSION

HIV prevalence among IDU in this study did not differ from the prevalences found among other IDU in Amsterdam. However, HIV prevalence among heterosexual non-IDU originating from Surinam and the Netherlands Antilles was high when compared with other non-IDU heterosexuals in Amsterdam and may indicate the presence of heterosexual transmission of HIV. Underreporting of risk behaviour or transmission through blood transfusion however, cannot be excluded completely.

Increasing antigenic and genetic diversity of the V3 variable domain of the human immunodeficiency virus envelope protein in the course of the AIDS epidemic

Population-wide variation in genomic RNA of human immunodeficiency virus type 1 (HIV-1) encompassing the V3 loop of the envelope protein was studied in serum samples of 74 newly infected individuals from three Dutch cohorts: 30 homosexual men, 32 drug users, and 12 hemophiliacs. During acute infection, HIV-1 RNA sequences present in serum are relatively homogeneous, which makes direct sequencing feasible. This offered an opportunity to study the infecting virus variants before mutations had accumulated in the new host. The sampling dates ranged from 1980 to 1991, thus spanning the entire AIDS epidemic in The Netherlands. The diversity in the sequenced region increased over time in both the homosexual and the drug-user risk groups. Furthermore, this increase was associated with an increase in antigenic variation, as witnessed by serum reactivity to a V3 peptide panel. Despite this diversification, some 1990 sequences still closely resembled the earliest 1980 sequence, making ancestral inferences problematic. No evidence was found of a change in the master sequence of the virus quasi-species over time. At the amino acid level, no risk-group-associated variation was found, but at the nucleotide level, the drug-user and homosexual/hemophiliac sequences could be distinguished on the basis of a single silent nucleotide change in the sequence encoding the tip of the V3 loop. Hemophiliac sequences could not be distinguished from those of homosexuals. In spite of the large and increasing genetic variability, all sequences were more similar to the European/American HIV consensus sequence than to that of non-Western strains.

Increase in unprotected anogenital intercourse among homosexual men

Results are presented from two sources, data of which indicate an increase in high-risk sexual behaviors for human immunodeficiency virus infection among homosexual men. The number of cases of gonorrhea among homosexual and bisexual visitors to municipal sexually transmitted disease clinics in Amsterdam, The Netherlands, is increasing. An increase was also observed in unprotected anogenital intercourse among homosexual participants in the Amsterdam cohort. These findings indicate that a rebound in the behavior change process among homosexual men is occurring. Furthermore, longitudinal behavioral data show that lapse and relapse into unsafe sex are prevalent in the Amsterdam cohort.

HIV prevalence and risk behaviour among prostitutes and clients in Amsterdam: migrants at increased risk for HIV infection

OBJECTIVES

To study groups of prostitutes and clients of prostitutes in order (i) to determine HIV prevalence and sexual risk behaviour, (ii) to determine differences between samples recruited within and outside a clinic for sexually transmitted diseases (STD) and (iii) to determine correlates of inconsistent condom use (ICU) among both groups.

DESIGN

Participants were interviewed and anonymously tested for HIV-antibody; approximately half were recruited at a clinic for sexually transmitted diseases (STD) and half at prostitute working places.

SETTING

An STD clinic and prostitute working places in Amsterdam in 1991.

SUBJECTS

201 female prostitutes without a history of injecting drugs and 213 male clients of female prostitutes.

MAIN OUTCOME MEASURES

antibodies to HIV, consistency of condom use in commercial vaginal contacts in the preceding 6 months.

RESULTS

HIV prevalence was low: three prostitutes (1.5%; 95% CI 0.5-4.6%) and one client (0.5%; 95% CI 0.1-3.3%) were infected. All three HIV positive prostitutes originated from AIDS-endemic countries, came to the Netherlands only recently and were recruited outside the STD clinic. Large differences between subgroups resulted from the two recruitment methods: while clients of prostitutes with relatively high risk behaviour were strongly represented among the STD clinic sample, high risk prostitutes were underrepresented in this sample. Consistent condom use (with 100% of contacts) was reported by 66% of prostitutes and 56% of clients of prostitutes. Inconsistent condom use was found to be high among prostitutes who had migrated from Latin America and among migrant clients of prostitutes.

CONCLUSIONS

When monitoring HIV infection one must take into account imported cases. HIV prevention efforts should be particularly focused at prostitutes from Latin America and at clients of prostitutes who migrated to the Netherlands.

The HIV epidemic and its effect on the tuberculosis situation in The Netherlands

To determine the influence of the HIV (human immunodeficiency virus) epidemic on the tuberculosis situation in the Netherlands, we made a retrospective analysis of all reported tuberculosis cases from 1984 through 1990. We studied the course of the tuberculosis incidence in the Netherlands among the group at highest risk for HIV infection (Dutch males, 25-49 years of age, in Amsterdam). This was compared with the course among same-age Dutch males in areas with lower risk for HIV infection and among other-age Dutch males in Amsterdam. The tuberculosis incidence among Dutch males aged 25-49 years in Amsterdam increased from 16.1 in 1984 to 34.7 per 100,000 in 1990 (chi 2 for trend, P < 0.01). The incidences among Dutch males in other places of residence in this age group and among other-age Dutch males in Amsterdam remained stable or decreased during the same period. As this increase could not be ascribed to tuberculosis among other risk groups, it appears to be related to the HIV epidemic among male homosexuals. Our results indicate that, even in a country where the prevalence of tuberculous infection is low, an increase of tuberculosis among certain subgroups can be observed as the result of the HIV epidemic.