Chlamydia trachomatis infection in a gynaecology clinic population: identification of high-risk groups and the value of contact tracing

Using ThinPrep Papanicolaou test samples to evaluate sexually transmitted infection screening practices

INTRODUCTION

We sought to evaluate the use of Papanicolaou samples as a screening tool for sexually transmitted infections (STIs).

METHODS

Retrospective chart review analyzing Papanicolaou samples for STI. Samples were processed and results compared to clinical data to assess this technique's viability. Cases and controls were matched by sample date. Characteristics of women with STI testing were compared in bivariate analyses.

RESULTS

We analyzed 50 STI-positive and 50 date-matched samples. Thirteen (26.0%) of the STI-positive patients were not screened at their visit. Women without STI screening were older (39.5 vs. 30.0 years, P = 0.001); non-Hispanic White (65.9% vs. 46.4%, P = 0.05); and married (60.0% vs. 26.9%, P = 0.005) than women with STI screening. Fifty-eight were offered and accepted STI testing at their visit; 37 samples were STI-positive: 17 (29.3%) Mycoplasma genitalium (Mgen), 10 (17.2%) chlamydia, 6 (10.3%) trichomoniasis, 1 (1.7%) gonorrhea, and 3 (5.2%) had two STIs. Among the 42 patients without STI testing, 12 (28.6%) had positive samples: 6 (14.3%) chlamydia, 5 (12.0%) Mgen, and 1 (2.4%) trichomoniasis.

CONCLUSIONS

Over one-quarter of STI-positive patients were not screened; though low-risk by current screening criteria, a significant number may harbor untreated STIs; using Papanicolaou samples may allow for increased screening in this population.

Contact tracing strategies in heterogeneous populations

Contact tracing is a well-established disease control measure that seeks to uncover cases by following chains of infection. This paper examines mathematical models of both single-step and iterative contact tracing schemes and analyses the ability of these procedures to trace core groups and the sensitivity of the intervention to the timescale of tracing. An iterative tracing process is shown to be particularly effective at uncovering high-risk individuals, and thus it provides a powerful public health tool. Further targeting of tracing effort is considered. When the population exhibits like-with-like (assortative) mixing the required effort for eradication can be significantly reduced by preferentially tracing the contacts of high-risk individuals; in populations where individuals have reliable information about their contacts, further gains in efficiency can be realized. Contact tracing is, therefore, potentially an even more potent tool than its present usage suggests.

Relationship of cervical ectopy to chlamydia infection in young women

OBJECTIVE

Genital Chlamydia trachomatis infection is the most common bacterial sexually transmitted infection (STI) in the UK. Behaviours including multiple sex partners and inconsistent condom use, and biological factors such as cervical ectopy, may increase susceptibility to STIs. Cervical ectopy is thought to increase risk of chlamydia infection by exposing columnar epithelium to a potential infectious inoculum. This study aimed to determine whether chlamydia was more prevalent in young women with cervical ectopy.

METHODS

Clinical notes of women aged 16-24 years attending the Portsmouth Genitourinary Medicine Clinic for an STI screen during the period May-July 2003 were reviewed retrospectively. Information collected included the presence or absence of cervical ectopy, smoking habits, methods of contraception, number of sexual partners in the previous 3 months, and previous STIs. Chlamydia infection was diagnosed by using strand displacement amplification on cervical swabs.

RESULTS

A total of 231 women were included in the study. The mean age was 19.8 years. Evidence of cervical ectopy was found in 107 women. Chlamydial infection was detected in 37.4% (40/107) of those women with cervical ectopy and 21.8% (27/124) in those without cervical ectopy. This difference was statistically significant (p = 0.009). The significance remained even when accounting for confounding variables.

CONCLUSIONS

Cervical ectopy is a common physiological process in young women. Recognition of cervical ectopy should alert the clinician to the possibility of a genital chlamydia infection. Opportunistic screening for chlamydia in young people should be offered to reduce the prevalence of infection and its sequelae.

[Screening of sexually transmitted diseases in clinical and non-clinical settings in Salvador, Bahia, Brazil]

The objectives were to study: (1) acceptance of STD screening in non-clinical settings for asymptomatic individuals; (2) risk factors and STD prevalence among individuals in non-clinical and clinical settings; and (3) non-clinical screening of asymptomatic populations as a feasible method for STD control. We recruited 139 males and 486 females between 18 and 30 years of age from a family planning clinic, schools, and community centers in low-income neighborhoods. We asked about STD symptoms and STD/HIV risk behaviors and tested the individuals for gonorrhea, Chlamydia, syphilis, and HIV. Except for HIV, women recruited directly from the community had higher STD rates than those who came in for care at the clinic. Screening in non-clinical settings in Brazil is feasible and has a high yield among young adults in low-income communities. Infected participants would likely never have otherwise sought care or been tested or treated. STD control efforts could be implemented in any site that can reach populations at risk and become a routine procedure in health care settings where people report for problems unrelated to STDs.

Hormonal contraceptive use and risk of sexually transmitted infections: a systematic review

Previous research has suggested that hormonal contraceptive users, compared with nonusers, may be at increased risk for acquiring sexually transmitted infections (STIs). We searched the MEDLINE and EMBASE databases for all articles from January 1966 through February 2005 for evidence relevant to all hormonal contraceptives and STIs (including cervical chlamydial and gonococcal infection, human papillomavirus, trichomoniasis, herpes and syphilis). We used standard abstract forms and grading systems to summarize and assess the quality of 83 identified studies. Studies of combined oral contraceptive and depot medroxyprogesterone use generally reported positive associations with cervical chlamydial infection, although not all associations were statistically significant. For other STIs, the findings suggested no association between hormonal contraceptive use and STI acquisition, or the results were too limited to draw any conclusions. Evidence was generally limited in both amount and quality, including inadequate adjustment for confounding, lack of appropriate control groups and small sample sizes. The observed positive associations may be due to a true association or to bias, such as differential exposure to STIs by contraceptive use or increased likelihood of STI detection among hormonal contraceptive users.

Chlamydia trachomatis in the United Kingdom: a systematic review and analysis of prevalence studies

OBJECTIVES

To undertake a systematic review to obtain estimates of genital Chlamydia trachomatis prevalence in various populations in the United Kingdom and Ireland; to determine which populations have the highest rates of infection; and to explore the most important determinants of infection.

METHODS

Electronic databases were searched using the keywords "chlamydia" and "England," "Wales," "UK," "Scotland," "Ireland," or "Britain." Additional unpublished data and references were solicited from experts. Studies were included in the analysis if C trachomatis prevalence was reported, and if they met inclusion criteria. Nine variables identified as potentially important descriptors of chlamydia prevalence were extracted from each study and analysed using various logistic regression models. Only studies reporting prevalence in female populations were included in the models, because there were few data from males.

RESULTS

357 studies were identified using the search methods, 90 of which met inclusion criteria, and 19 of which contributed to the final model. The most influential variables on prevalence were age and setting of the population tested. In general practice surgeries, the under 20 year old age group had an estimated prevalence of 8.1% (95% CI 6.5 to 9.9), 20-24 year olds 5.2% (95% CI 4.3 to 6.3), 25-29 year olds 2.6% (95% CI 2.0 to 3.3), decreasing to 1.4% (95% CI 1.0 to 1.9) in those aged over 30 years. Overall, healthcare settings had higher prevalence estimates than population based studies. For example, among under 20 year olds, estimates were 17.3% (95% CI 13.6 to 21.8) in genitourinary medicine clinics, 12.6% (95% CI 6.4 to 23.2) in antenatal clinics, 12.3% (95% CI 9.8 to 15.3) in termination of pregnancy clinics, 10.7% (95% CI 8.3 to 13.8) in youth clinics, 10.0% (95% CI 8.7 to 11.5) in family planning clinics, and 8.1% (95% CI 6.5 to 9.9) in general practice, compared to 5.0% (95% CI 3.2 to 7.6) in population based studies. The type of test, specimen used, date, and location of test were not strongly associated with chlamydia prevalence.

CONCLUSION

The chlamydia prevalence estimates by age and setting from the model may be used to inform chlamydia screening strategies. The systematic review revealed much heterogeneity in the studies identified, but with clear patterns of prevalence. It also indicated gaps in the knowledge about chlamydia prevalence in certain subgroups such as men and the general population.

Gender Differences in Bacterial STIs in Canada

HEALTH ISSUE: The incidence of bacterial sexually transmitted infections (STIs) is rising in Canada. If these curable infections were prevented and treated, serious long-term sequelae including infertility, and associated treatment costs, could be dramatically reduced. STIs pose a greater risk to women than men in many ways, and further gender differences exist in screening and diagnosis. KEY FINDINGS: Reported incidence rates of chlamydia, gonorrhea, and infectious syphilis declined until 1997, when the trend began to reverse. The reported rate of chlamydia is much higher among women than men, whereas the reverse is true for gonorrhea and infectious syphilis. Increases in high-risk sexual behaviour among men who have sex with men were observed after the introduction of potent HIV suppressive therapy in 1996, but behavioural changes in women await further research. DATA GAPS AND RECOMMENDATIONS: STI surveillance in Canada needs improvement. Reported rates underestimate the true incidence. Gender-specific behavioural changes must be monitored to enhance responsiveness to groups at highest risk, and more research is needed on effective strategies to promote safer sexual practices. Geographic and ethnic disparities, gaps, and needs must be addressed. Urine screening for chlamydia should be more widely available for women as well as men, particularly among high-risk men in order to prevent re-infections in their partners. As women are more likely to present for health examinations (e.g. Pap tests), these screening opportunities must be utilized. Female-controlled methods of STI prevention, such as safer topical microbicides, are urgently needed.

Assessment of Chlamydia trachomatis infection of semen specimens by ligase chain reaction

Diagnostic potential of the Chlamydia trachomatis ligase chain reaction system (LCx) to assess the presence of C. trachomatis in urine and semen specimens was evaluated. Paired urine and semen specimens from 153 asymptomatic male partners of subfertile couples attending our Center for Reproductive Medicine were examined by LCx. As controls, 19 semen samples from four donors who were participating in the programme for artificial insemination were used. Of these, 12 samples had previously been shown to be C. trachomatis-positive by an in-house PCR. C. trachomatis was detected by LCx in seven of 153 (5 %) urine samples. None of the 153 semen samples tested positive by LCx. Also, none of the 12 C. trachomatis-containing control semen samples were positive by LCx. By in-house PCR, seven urine specimens and two of 153 (1 %) semen samples tested positive. The corresponding urine samples of these male partners were also C. trachomatis-positive, as well as the 12 C. trachomatis-containing samples from donors. In conclusion, LCx is not sensitive enough to assess the presence of C. trachomatis in semen specimens; therefore, this method is not recommended to routinely screen semen specimens from donors who participate in programmes for artificial insemination or male partners of subfertile couples for C. trachomatis.

PCR assessment of Chlamydia trachomatis infection of semen specimens processed for artificial insemination

In order to ascertain the microbiological quality of stored semen specimens processed for artificial insemination by a donor (AID), we developed a PCR assay targeting the chlamydial plasmid to detect Chlamydia trachomatis in semen. The lower limit of detection of this assay corresponded to 2.5 to 5 elementary bodies per microl of semen. A total of 669 cryopreserved ejaculates from 97 asymptomatic donors were tested for C. trachomatis infection. Twelve ejaculates, originating from four donors, were found to be positive, indicating a 4% prevalence of C. trachomatis infection among the donor population studied. Cross-contamination between the cryopreserved specimens in the storage container was studied by typing using sequence analysis of PCR-amplified omp1 genes of the strains. Two donors were infected with serovar E, one was infected with serovar F, and one was infected with serovar K. For two donors, the duration of C. trachomatis positivity could be assessed. One donor donated C. trachomatis-positive semen for at least 4 successive months, and the other did so for at least 16 months. The occurrence of C. trachomatis infection in cryopreserved donor semen indicates that ejaculates from donors not tested for a C. trachomatis infection just prior to donation should be tested for infection by a direct test such as the PCR described here. Direct testing of semen specimens will detect not only donors with an active infection but also C. trachomatis-infected ejaculates already stored and will thus improve the microbiological quality of AID, since discrepancies in the presence of C. trachomatis in urine and semen specimens have been reported.

STD testing policies and practices in U.S. city and county jails

BACKGROUND AND OBJECTIVES

Studies have shown that sexually transmitted disease (STD) rates are high in the incarcerated population. However, little is known about STD testing policies or practices in jails.

GOAL

To assess STD testing policies and practices in jails.

STUDY DESIGN

The Division of STD Prevention developed and distributed an e-mail survey to 94 counties reporting more than 40 primary and secondary cases in 1996 or having cities with more than 200,000 persons. State and local STD program managers completed the assessment in collaboration with health departments and the main jail facilities in the selected counties.

RESULTS

Most facilities (52-77%) had a policy for STD screening based only on symptoms or by arrestee request, and in these facilities, 0.2% to 6% of arrestees were tested. Facilities having a policy of offering routine testing tested only 3% to 45% of arrestees. Large facilities, facilities using public providers, and facilities routinely testing for syphilis using Stat RPR tested significantly more arrestees (P<0.05). Approximately half of the arrestees were released within 48 hours after intake, whereas 45% of facilities did not have STD testing results until after 48 hours.

CONCLUSION

Most facilities had a policy for STD screening based only on symptoms or by arrestee request. Facilities having a policy of routine STD testing are not testing most of the arrestees. There is a small window (<48 hours) for STD testing and treatment before release. Smaller jails and facilities using private providers may need additional resources to increase STD testing levels. Correctional facilities should be considered an important setting for STD public health intervention where routine rapid STD screening and treatment on-site could be implemented.

The rapid test paradox: when fewer cases detected lead to more cases treated: a decision analysis of tests for Chlamydia trachomatis

BACKGROUND AND OBJECTIVES

Screening tests for detection of Chlamydia trachomatis include those processed in laboratories and those designed to be processed at the point of care. The latter tests can yield results at the time of the initial patient visit, but most available lab-processed tests have greater sensitivity. In settings where a proportion of patients do not return for treatment after positive test results, the less sensitive rapid tests could lead to the treatment of more patients and be more cost-effective.

GOAL OF THIS STUDY

To determine the situations, if any, in which a rapid test might be more cost-effective and treat more infections than lab-based tests.

STUDY DESIGN

A decision analysis framework was used to compare one point-of-care test (the BioStar Chlamydia OIA) with two lab-based tests (cell culture and the polymerase chain reaction [PCR] assay). It was assumed that all women in the model would be screened. Variables included in the analysis were the prevalence, test sensitivity and specificity, the probability of developing pelvic inflammatory disease after treated and untreated chlamydial infections, and the likelihood that patients would wait for rapid test results or return to the facility for treatment.

RESULTS

The rapid test treated more cases of infection than the PCR alone if the return rate was less than 65%. A two-test algorithm of the rapid test followed by a PCR test on those initially testing negative identified and treated the greatest number of chlamydial infections and was the most cost-effective at all prevalences above 9%, but this finding was sensitive to the cost estimate for pelvic inflammatory disease.

CONCLUSION

In settings where patient return for treatment is a problem, point-of-care tests contribute significantly to the detection and treatment of chlamydial infections among women.

Heterosexual HIV transmission and STD prevalence: predictions of a theoretical model

BACKGROUND

Previous studies suggest that concurrent sexually transmitted infection may enhance HIV transmission. This paper explores some theoretical consequences of this using a mathematical model of transmission of HIV and other STD pathogens.

OBJECTIVES

To develop a deterministic mathematical model to describe the heterosexual transmission dynamics of both HIV and a bacterial STD.

STUDY DESIGN

We used survey derived estimates of sexual behaviour in a young heterosexual London population in our deterministic mathematical model to estimate the effects on an HIV epidemic of different levels of STD prevalence in such a population.

RESULTS

We show that the predictions of the model are plausible and suggest that, even under conditions both of low STD prevalence and of low HIV transmission enhancement, a substantial proportion of HIV transmission events may be attributable to concurrent STD.

CONCLUSIONS

It is likely that epidemics of heterosexually transmitted HIV infection in industrialised countries have been limited in size by the relative success of efforts to control STD. None the less, a significant proportion of heterosexual transmission events which do occur may be attributable to concurrent STD. In developing countries, cheap and simple STD care is likely to be a highly cost effective strategy to prevent HIV transmission.

Patient referral outcome in gonorrhoea and chlamydial infections

OBJECTIVE

To describe the outcome of patient referral at the STD clinic of the University Hospital Rotterdam. To study characteristics of heterosexual index patients and partnerships related to referral outcome.

METHODS

In 1994, patients with gonorrhoea and chlamydia were referred to public health nurses for interview and patient referral. Referral outcome was classified as "verified" if partners attended the STD clinic and as "believed" if partners were said to have attended elsewhere.

RESULTS

Of 454 patients, 250 (55%) participated in the study. The outcome of patient referral for the 502 eligible partners was 103 (20.5%) verified referrals, 102 (20%) believed referrals, and 297 (59%) with unknown follow up. Of the 103 partners examined, 43 had an STD of which 63% reported no symptoms. The contact finding ratio was higher for chlamydia patients and heterosexual men. Also, referral was more effective for index patients with recent sexual contact, with follow up visits to the public health nurse, for men who were not commercial sex worker (CSW) clients, and, to a lesser degree, for Dutch patients and patients who sometimes used condoms. For steady partners, referral was improved if the last sexual contact was more recent. Casual partners visited the clinic more often if sexual contact occurred more than once, if the last contact was more recent, if they were older, and if they were Dutch.

CONCLUSIONS

Patient referral was more effective for certain groups, such as chlamydia patients and steady partners, but was inadequate for others, including CSW and their clients, other "one night stands", young partners, and ethnic minorities.

Partner notification to prevent pelvic inflammatory disease in women. Cost-effectiveness of two strategies

BACKGROUND AND OBJECTIVES

Partner notification is an important strategy for prevention of Chlamydia trachomatis infection and pelvic inflammatory disease (PID). PID can be prevented by early diagnosis and treatment of the female sex partners of men infected with C. trachomatis (strategy 1) and by preventing reinfection in women through diagnosis and treatment of their male sex partners (strategy 2).

STUDY DESIGN

Using a decision model, the cost-effectiveness of strategies 1 and 2 was compared to no partner notification. Outcomes were measured by cases of PID prevented and net costs expended from a health care system perspective.

RESULTS

In a hypothetical cohort of 1,000 male and 1,000 female index patients, strategy 1 prevented 64 and strategy 2 prevented 20 cases of PID. Strategy 1 saved $247,000 and strategy 2 saved $33,000 over no partner notification. Sensitivity analysis showed that strategy 1 was cost-effective across a wide range of assumptions. Strategy 2 was cost-effective at baseline, but its cost-saving ability was subject to changes in the model.

CONCLUSION

Partner notification of both male and female index patients is a cost-effective public health strategy for prevention of PID. In most settings, both strategies can and should be implemented.

Epidemiology of genital Chlamydia trachomatis in England and Wales

OBJECTIVE

To describe the recent epidemiology of genital Chlamydia trachomatis infection in England and Wales.

DESIGN

Retrospective study of routinely available surveillance datasets and ad hoc prevalence studies.

METHODS

Numbers of new cases of genital C trachomatis infection, obtained from the Department of Health and Welsh Office, were combined with the estimated mid-year resident population of England and Wales. Rates were analysed for trend over time using a log linear age period model in GLIM4. Ad hoc prevalence and case finding studies carried out over the past 20 years were critically assessed in terms of study design and testing methodologies.

RESULTS

Attendance rates at genitourinary medicine (GUM) clinics were higher for women than men over the period 1989 to 1994 as were the number of laboratory reports. The highest rate of attendance (GUM clinic data) was for women aged 16 to 19 years. There was an overall significant linear decrease in the attendance rates over time for both men (p = 0.0172) and women (p = 0.0000) between 1989 and 1994. There was considerable variation in the prevalence of genital C trachomatis infection detected within different clinical settings, together with a substantial level of asymptomatic infection.

CONCLUSIONS

Genital C trachomatis infection is broadly distributed throughout the sexually active population, with a substantial reservoir of asymptomatic infection among those generally perceived to be at low risk of a sexually transmitted infection. Young people, particularly women aged 16 to 19 years, are at highest risk of genital C trachomatis infection. This is of concern since younger women are more susceptible than older women to developing complications of chlamydial infection, such as pelvic inflammatory disease. The broad distribution of infection across all sexually active health service attenders and the high level of asymptomatic infection suggest that a new, screening based, approach to the control of genital C trachomatis infection is required. Recommendations are made as to the epidemiological research required to guide such work.

The role of epidemiology and surveillance systems in the control of sexually transmitted diseases

Surveillance and epidemiological studies are essential components of effective control programmes for sexually transmitted diseases. While other forms of basic biomedical research may add to our understanding of why an exposure or behaviour causes or prevents disease, only epidemiology allows the quantification of the magnitude of the exposure-disease relationship in humans. It is this measure of the association between risk and disease that is needed to inform rational policy on altering risk through intervention. Surveillance data are used both to determine the need for public health action and to assess the effectiveness of programmes: they are required for the setting of priorities, for planning and resource allocation, for the definition of population subgroups and risky behaviours for targeted interventions, for the development of disease prevention programmes, and for the evaluation of interventions. Data from surveillance systems and epidemiological studies can also inform diagnostic and therapeutic practice, and indicate areas for further research. Over the last 20 years chlamydia infections and viral agents have emerged as the major cause of STD in developed countries, and with this change in the aetiological mix of STD cases the focus of prevention and control of STDs has shifted from treatment and partner notification towards health education. In developing countries there is an urgent need for appropriate surveillance infrastructures, particularly now that there is evidence that STD control programmes, informed by surveillance data, can reduce HIV transmission at the population level. The importance of surveillance and epidemiology in the control of STDs is set to increase in the face of the changing pattern of sexually transmitted pathogens. The challenge to clinicians and epidemiologists is to work together in developing systems that will inform new approaches to control and prevention.

Prevalence and serovar distribution of asymptomatic cervical Chlamydia trachomatis infections as determined by highly sensitive PCR

The prevalence rates and serovar distributions of Chlamydia trachomatis cervical infections were investigated in two different groups of women. Group I consisted of 393 asymptomatic young women (aged 17 to 30 years) who were invited to participate in a C. trachomatis screening program. Group II consisted of 734 randomly selected patients (aged 17 to 68 years) attending an inner-city gynecological outpatient clinic. C. trachomatis was detected in cervical scrapes by PCR specific for endogenous plasmid. These plasmid PCR-positive samples were subsequently subjected to genotyping by C. trachomatis-specific omp1 PCR-based restriction fragment length polymorphism analysis (J. Lan, J. M. M. Walboomers, R. Roosendaal, G. J. van Doornum, D. M. MacLaren, C. J. L. M. Meijer, and A. J. C. van den Brule, J. Clin. Microbiol. 31:1060-1065, 1993). The overall prevalence rates of C. trachomatis found in patients younger than 30 years were 9.2 and 11.8% in groups I and II, respectively. A clear age dependency was seen in group II, with the highest prevalence rate (20%) found in patients younger than 20 years, while the rate declined significantly after 30 years of age (5.9%). In women younger than 30 years, the genotyping results showed that serovars E, I, and D (in decreasing order) were frequent in group I, while serovars F, E, and G (in decreasing order) were predominantly found in group II. The study shows that C. trachomatis infections are highly prevalent in asymptomatic young women. The different serovar distributions found most likely reflect the different compositions of the study groups, but additional analysis of the case histories of individual patients suggests that certain serovars might be associated with symptomatic (i.e., serovar G) or asymptomatic (i.e., serovars D and I) infections.

Early- and late-onset pelvic inflammatory disease among women with cervical Chlamydia trachomatis infection at the time of induced abortion--a follow-up study

After termination of a double-blind, randomized study on erythromycin in the prevention of post-abortion infection, 34 women (14 treated with erythromycin, 20 not treated with erythromycin) harbouring Chlamydia trachomatis were followed up within 6 weeks and again 2 to 24 months after the abortion in order to detect an early- and late-onset pelvic inflammatory disease (PID). For statistical analysis survival analysis by Kaplan-Meir estimates and Mantel-Cox test were carried out. Untreated women with C. trachomatis infection at the time of abortion had a cumulative risk of 72% of developing early and/or late PID, if observed for 24 months. This cumulative risk was significantly reduced to 8% if the C. trachomatis infection was treated at the time of the abortion. Screening for and treatment of C. trachomatis is warranted, especially in women < or = 25 years old, to avoid early and late-onset PID after induced first trimester abortion.

Risk profiles for genital infection in women

OBJECTIVE

To determine independent risks with predictive value for specific sexually transmitted diseases in women.

DESIGN

A prospective study of reported sexual behaviour in patients who presented for screening and diagnosis of sexually transmitted diseases.

SETTING

A genitourinary medicine clinic at the West London Hospital.

SUBJECTS

1025 consecutive newly attending patients who completed a sexual behaviour questionnaire between February and June 1982.

MAIN OUTCOME MEASURES

Sexual behaviour reported by standardised self-administered questionnaire and sexually transmitted diseases diagnosed by routine clinical and laboratory methods.

RESULTS

Independent risks for gonorrhoea were teenage (RR 2.0), black race (RR 2.0), more than two partners in the past year (RR 2.2) and previous pregnancy (RR 2.1). Trichomoniasis (RR 2.5), chlamydial infection (RR 1.8) and pelvic inflammatory disease (RR 4.8) also had significant predictive value. Conversely, gonorrhoea proved a risk for chlamydial infection (RR 2.1) together with age under 25 years (RR 2.3) and more than five partners in the previous year (RR 2.2). Ano-genital herpes was predicted by a total of more than 10 sexual partners (RR 2.6) and by both anal (RR 2.2) and oral intercourse (RR 2.9). Age under 25 years was the only independent risk for ano-genital warts (RR 2.0). We found no evidence that either vaginal candidosis or bacterial vaginosis were sexually transmitted. The risk for any genital infection was increased by more than one sexual partner in the preceding year (RR 1.7) and black race (RR 2.0).

CONCLUSIONS

Sexually transmitted diseases show both similarities and differences in the risk factors associated with their transmission. These risk profiles facilitate the targeting of health education measures for those sections of the community at greatest risk and form a baseline for the future assessment of the effects of condom protected sexual intercourse and other safer sexual practices.

Health gains from screening for infection of the lower genital tract in women attending for termination of pregnancy

Infection of the upper genital tract after abortion is well recognised, but routine screening for infection before termination is rare, and few centres are aware of the prevalence of post-abortion complications in their population. We undertook a study to assess the prevalence and sequelae of genital-tract infection in patients undergoing termination of pregnancy and to estimate the costs and potential benefits of introducing screening and prophylaxis for the most commonly found organisms. The study in Swansea, UK, was of 401 consecutive patients attending for termination of pregnancy; only 1 patient refused to take part. Immediately before the termination procedure vaginal and cervical swabs were taken for microscopic examination and culture of Trichomonas vaginalis, Neisseria gonorrhoeae, and candida species. We sought Chlamydia trachomatis by enzyme-linked immunosorbent assay. 112 (28%) women had the typical bacterial flora of anaerobic (bacterial) vaginosis, 95 (24%) had candidal infection, 32 (8%) chlamydial infection, 3 (0.75%) trichomonas infection, and 1 (0.25%) gonorrhoea. Postoperative follow-up of 30 of the women with chlamydial infection showed that pelvic infection developed in 19 (63%), of whom 7 were readmitted to hospital. 9 male partners of women with chlamydial (plus gonococcal in 1 case) infection were examined; 8 were symptom-free, 3 had C trachomatis infection, and 1 N gonorrhoeae. Estimated costs of hospital admissions for complications of chlamydial infection were more than double the costs of providing a routine chlamydia screening programme and prophylactic treatment. Screening for chlamydial infection before termination of pregnancy is essential. Prophylactic treatment for both chlamydial infection and anaerobic vaginosis should also be considered. Male partners of women infected with chlamydia are often symptom-free, but they must be traced to avoid reinfections.

Evaluation of laparoscopy and endocervical swab in the diagnosis of Chlamydia trachomatis infection of the female genital tract

A group of 60 consecutive women admitted to the gynaecology department of Eastbourne District General Hospital for pelvic pain were entered into this study. Evidence of C. trachomatis infection of the genital tract was investigated by detection of chlamydial lipopolysaccharide antigen in the peritoneal fluid collected from the pouch of Douglas during laparoscopy and in the endocervical swab. The test used was an Enzyme-Linked Immunosorbent Assay (ELISA). Peritoneal fluid was positive in 11 subjects (18%, P < 0.05), endocervical swab was positive in 3 (5%, P < 0.05). The difference was statistically significant (P = 0.01, two tailed test at 1% level). Ten women with a positive ELISA on the peritoneal fluid had a negative cervical swab, 2 women with a positive cervical swab had negative peritoneal fluid and in only one woman were both cervical swab and peritoneal fluid positive.

Infection due to Chlamydia trachomatis in pregnancy and the newborn

Bacteria in the genus Chlamydia comprise three species, C. trachomatis, C. psittaci and C. pneumoniae. C. trachomatis infection is common, varying in prevalence in women from 0% to 37%. In the United States, the prevalence rate is estimated currently to be about 5%. Pregnancy may predispose to an increased chance of infection with C. trachomatis, through physiological immunosuppression and/or cervical ectopy. Maternal antibodies to C. trachomatis provide limited, if any, protection for the newborn. C. trachomatis causes pelvic inflammatory disease--which can result in tubal infertility or ectopic pregnancy and postabortal or late postpartum endometritis. It may also cause chorioamnionitis and premature delivery of the fetus. The incidence of vertical transmission of chlamydiae from mother to baby varies; if the mother is untreated, 20-50% of the newborns will develop conjunctivitis and 10-20% will develop pneumonia. C. psittaci infection in pregnancy is rare, but can cause spontaneous abortion. Whether C. pneumoniae infection in pregnancy has any influence on the outcome has not been ascertained. C. trachomatis can be detected by one or more of several methods; enzyme immunoassays are the least sensitive, but the most widely used. Screening for C. trachomatis in pregnancy may be of benefit in areas of high prevalence, and is generally regarded as being cost-effective if the prevalence rate is more than 5%. Pregnant women are best treated with erythromycin, 250 mg four times daily for 7 days. This will prevent infection of the newborn in more than 90% of cases. The infected neonate should be treated with erythromycin, given systemically and also with topical tetracycline if conjunctivitis is present.

Chlamydial genital infections and laparoscopic findings in infertile women

Several studies have shown that previous chlamydial genital infection, reflected by serological markers, is strongly associated with tubal damage leading to tubal infertility. In 105 women undergoing laparoscopy, multiple samples were collected from the lower (urethra and cervix) and upper (endometrium, peritoneal fluid, tubal lumen) genital tract, in order to isolate Chlamydia trachomatis in cell culture. Chlamydia trachomatis was isolated from at least one site in 13 (30.9%) of 42 infertile women with tubal infertility, in 5 (12.1%) of 41 women with unexplained infertility, in 1 of 4 women affected by acute salpingitis and in 1 (5.5%) of 18 women with endometriosis or uterine malformations. The latter group was the control group. Thirteen (65%) of the 20 positive women harboured Chlamydia trachomatis in their upper genital tract alone and 16 women were positive in one or both tubes. Only one of the positive women showed laparoscopic signs of acute pelvic infection. Four of the 5 positive women with unexplained infertility harboured Chlamydia trachomatis in the tubal lumen. This study confirms that chlamydial infection is strongly associated with tubal damage. It suggests that cervical cultures are inadequate for excluding a tubal infection and that chlamydial colonization of the tubal mucosa is possible in the absence of symptoms and laparoscopic signs of active infection.

Risk factors for Chlamydia trachomatis infection in 6810 young women attending family planning clinics

Screening programmes are important for the control of Chlamydia trachomatis (Ct) infection, a disease spread mainly by asymptomatic carriers. Risk factors for Ct infection were assessed in 6810 consecutive asymptomatic young women seeking contraceptive advice. All women filled in a questionnaire and were offered Ct testing. Of the 5785 who consented to testing, 425 (7.3%) were Ct culture positive. Four variables were significantly related to increased risk of being infected: age 18-23 years, duration of present relationship less than 1 year, non-use of condoms, and a history of not having had a previous genital infection. It is not possible to devise screening criteria that would effectively identify women at high risk. Therefore a screening programme should be targeted at all sexually active young people. However, if after some years the programme succeeds in lowering general Ct prevalence, these factors may be important when selecting patients for Ct testing.

Efficacy of partner notification for HIV infection

Since 1985, partner notification has been part of Swedish policy to prevent the spread of human immunodeficiency virus (HIV) infection. Potentially infected partners of a newly diagnosed seropositive patient are notified either by the index patient or by the physician and referred for counselling. The efficacy of this strategy was assessed over 18 months in 1989-90. 365 HIV-seropositive index patients (91% of the 403 patients diagnosed in Sweden during the study period) reported 564 sexual or needle-sharing contacts. 390 contacts were located and counselled and HIV test results are known for 350 of them. In 53 of the 350 cases, previously unknown seropositivity was diagnosed. Partner notification for HIV should be viewed as a strategy to offer counselling and testing to a high-prevalence group of people. In a country where general HIV prevalence is low, the strategy is cost-effective for location and counselling of unknowingly seropositive individuals.

Prevalence of Chlamydia trachomatis infection in women having cervical smear tests

OBJECTIVE

To determine the prevalence of sexually transmitted diseases in patients with normal and abnormal cervical smears.

DESIGN

A prospective study of asymptomatic women with normal cervical smears attending their general practitioner and newly referred patients with abnormal smears attending a colposcopy clinic.

SETTING

A hospital based colposcopy clinic and an urban general practice (list size 5500) in north west Glasgow.

SUBJECTS

197 asymptomatic women attending their general practitioner for cervical smear tests and 101 randomly selected patients attending the colposcopy clinic for investigation of abnormal smears.

MAIN OUTCOME MEASURES

Presence of various sexually transmitted infections as determined by culture and serological tests.

RESULTS

Of the 101 women with cytological abnormalities, six had current chlamydial infection proved by culture and none had gonococcal infection; of the 197 women with normal smears, 24 (12%) had a chlamydial infection and two had gonorrhoea. Serological studies for Chlamydia trachomatis specific antibody also indicated that a large proportion of patients had been exposed to this agent in both groups. There was no significant difference between the groups in the prevalence of any sexually transmitted disease studied.

CONCLUSION

A high prevalence of chlamydial infection is present in women in north west Glasgow irrespective of their cervical cytological state.

Chlamydia trachomatis: the prevalence, trend and importance in initial infertility management

One thousand and five women, and 354 of their partners, attending an infertility clinic have been assessed for the presence of Chlamydia trachomatis antibodies in their serum. The overall prevalence in women was 12.4% (125/1,005) but appeared to have increased over a 2-year period. A similar trend was not apparent for men and the prevalence was only 4.2% (15/354). Of the 125 seropositive women 81 had their pelvis examined for the first time by laparoscopy. Fifty seven had tubal disease of varying severity, but only 16 had had an ectopic pregnancy or admitted to a previous history of pelvic inflammatory disease or nonspecific urethritis. These findings suggest that laboratory testing for chlamydial antibodies should be routine in the initial investigation of an infertile couple and that early laparoscopy is indicated in seropositive women.