VOL: 102, ISSUE: 13, PAGE NO: 44
Debbie Holland, RGN MSc, is lead nurse, Pulse Project, Camden PCT, LondonChlamydia trachomatis is the most common curable bacterial sexually transmitted infection (STI) and a well-document...
Chlamydia trachomatis is the most common curable bacterial sexually transmitted infection (STI) and a well-documented cause of reproductive and sexual morbidity in women and men. If left untreated in women, it can lead to pelvic inflammatory disease, chronic pelvic pain, ectopic pregnancy and infertility; untreated in men it can cause non-gonococcal urethritis, epididymitis, prostatitis, Reiter's syndrome, sexually-acquired reactive arthritis (SARA) and infertility (Stamm, 2000).
Most genital chlamydia infections in men and women are asymptomatic or cause non-specific symptoms, and therefore the screening of sexually active persons is the cornerstone of prevention strategies and is essential for STI control. Traditionally, screening for chlamydia has been limited by
- The need for an invasive examination to obtain cervical or urethral specimens;
- The insensitivity of conventional diagnostic tests and therefore the failure to identify all those infected;
- The difficulty of accessing high-risk populations, especially teenagers.
The development of new, non-invasive, highly sensitive screening tests for chlamydia that can be performed on urine specimens and self-taken swabs (Box 1) has removed many of those obstacles, and facilitated the implementation of a National Chlamydia Screening Programme (NCSP).
Reported cases of chlamydia are continuing to rise across England, Wales and Northern Ireland, with sustained increases in new diagnoses and attendance at GUM clinics (Health Protection Agency, 2005). In 2004, 103, 763 diagnoses of chlamydia infection were reported by GUM clinics. The highest rates continue to be seen in young people, specifically men and women under 24 years. Some of these increases are the result of increased awareness of STIs and more people using GUM services, up-take of screening in non-GUM settings, and improvements in diagnostic tests. However, high-risk sexual behaviour undoubtedly remains a significant contributing factor, compounded by asymptomatic infection, poor access to GUM services and ineffective partner notification.
Infection with chlamydia is often sub-clinical, which means that large numbers of men and women are unaware that they are infected and therefore remain untreated. Because women bear the main burden of morbidity from chlamydia infection, most clinical research, including incident surveys and case studies, has been in female populations.
In women, 80% of endocervical infections caused by Chlamydia trachomatis are without characteristic signs and symptoms, and may persist for years. If present, the symptoms are non-specific: altered vaginal discharge, inter-menstrual or post-coital bleeding and dysuria. Dyspareunia and/or lower abdominal pain are symptoms of complicated and ascending infection; for example, pelvic inflammatory disease (Stamm, 2000).
The signs, symptoms and complications of chlamydia infection are less well documented in men and a full clinical picture of the consequences of untreated male infection is not available. Like women, most men (70%) have no obvious symptoms of infection, but they can complain of dysuria, 'tingling' or a 'burning' feeling in the urethra and at the meatus. Less commonly, a scanty to moderate urethral discharge may be seen. Usually this is mucoid, clear or milky, but it can be mucopurulent (Stamm, 2000).
Chlamydia trachomatis is a bacterium that behaves like a virus (it is intracellular), therefore traditional diagnostic tests, such as EIA (antigen detection tests) have relied on obtaining enough infectious organisms from the site swabbed - the cervix or male urethra - with consequent reduced sensitivity in poor quality sampling and in patients without symptoms.
The development of nucleic acid amplification assays (NAATs) to diagnose chlamydia has revolutionised both the potential for improved case detection and the ability to screen larger, asymptomatic populations for infection. These tests are based on the amplification of selected DNA sequences, and can be performed on non-invasive clinical specimens such as first void urine, as well as endocervical, urethral and self-taken vaginal swabs.
A number of studies have shown NAATs to be highly sensitive ((gt)95%) and specific ((gt)99.5%) compared with both EIA and cell culture, as well as less dependent on specimen quality, transport conditions and the expertise of laboratory staff (Grun and Sheldon, 1996). However, these techniques are expensive in staff, space and consumables when compared with EIA, and their availability outside GUM clinics has been hampered in some areas because of the short-term financial costs.
NAATs are the diagnostic tests of choice in the NCSP, and are now routine in GUM clinics. They are a significant factor in improving detection rates.
Treatment of chlamydia
Antibiotic therapy with a tetracycline is an effective, curative treatment for genital chlamydia infection. Current clinical guidelines recommend the prescribing of doxycycline 100mg twice daily for seven days. The course must be completed, and patients advised against sexual intercourse until they have completed the course and until their sexual partner(s) has been treated. A single dose of azithromycin 1g, while more expensive, is as effective as doxycycline. Furthermore, it is well tolerated, has fewer side-effects, facilitates compliance and completion of treatment and does not affect oral contraception.
Follow-up, including partner notification (the testing and treating of partners of an identified case), is essential.
Background to the National Chlamydia Screening Programme
In England and Wales, cases of Chlamydia trachomatis are reported to and published by the Health Protection Agency Communicable Disease Surveillance Centre and CDSC Wales, based on statistical returns (KC60) from the UK's network of GUM clinics and laboratory reports. This dataset, while comprehensive, is likely to underestimate the true prevalence of infection in the community: it is estimated that diagnosis in GUM clinics represents only about 10% of prevalent infection (Chief Medical Officer, 1998).
As a significant proportion of cases are asymptomatic, they are likely to go undetected, thereby increasing the risk of complications, such as a woman with chlamydia developing pelvic inflammatory disease. Screening for genital chlamydia infection has been shown to reduce pelvic inflammatory disease and ectopic pregnancy (Scholes et al, 1996).
The National Strategy for Sexual Health and HIV (DH, 2001) provides a broad 10-year strategy for addressing the UK's high and increasing STI and teenage pregnancy rate and improving the care of people living with HIV. The strategy outlines a framework for service delivery incorporating primary and specialist sexual and reproductive healthcare services, with the aim of widening access to sexual healthcare, and ultimately reducing the rates of STIs, including HIV.
In response to the increasing incidence of chlamydia infection in young people in the UK, and the consequent clinical and economic costs of untreated infection, the phased implementation of the National Chlamydia Screening Programme (NCSP) began in September 2002. Importantly, the revolution in chlamydia diagnostics removed traditional barriers to chlamydia testing that required invasive genital swabs and transformed the opportunities for screening outside GUM clinics.
The NCSP identifies groups that should be targeted for screening (Box 2).
The programme identifies family planning clinics and general practices as key sites for opportunistic screening; for example, when women attend for routine cervical cytology screening, or for contraception advice. The programme also emphasises the importance of follow-up and treatment of the partners of infected individuals, which should be carried out in collaboration with GUM clinics.
There are three basic reasons why women have been targeted for screening:
- Health benefits pertinent to them - the aim is to reduce pelvic inflammatory disease;
- Cost-effectiveness - computer modelling suggests that screening asymptomatic women may be more cost-effective;
- Their accessibility - young women are more likely to be current users of a variety of healthcare services.
The hidden costs of chlamydia screening in women
While the health benefits of implementing the NCSP and concentrating on women are evident, the social and cultural implications of focusing screening on asymptomatic young women, but not men, are less clear. Excluding men as co-targets of screening is seen by critics as being a missed opportunity for obtaining epidemiological data about chlamydia in this population and better evidence about men's participation and role in chlamydia control.
Historically, the study and control of STIs has focused on women as both the 'victims' and transmitters of infection. Such a view has biased clinical and epidemiological research and resulted in relative ignorance about men and chlamydia and STIs in general. For this reason, little is known about male infection rates, signs, symptoms and risk factors for infection, while many healthcare providers continue to perceive chlamydia, like other STIs, as a women's issue, or as being outside their clinical expertise and/or role (Fenton, 2000).
Duncan and Hart (1999) have discussed the unintended negative consequences of focusing STI surveillance and control on women. These include the reinforcing of sexual inequalities, stigma, and the 'double standard', which sees women as both transmitters and contractors of infection.
By involving men only peripherally, the NCSP strategy does little to challenge the myth that men are just contacts of infected women. Furthermore, gender-specific screening does not address the lack of knowledge and research about heterosexual men's understanding, beliefs and attitudes to sexual and reproductive health, and may reinforce gender inequalities that disadvantage men as well as women.
In a qualitative study by Darroch et al (2003) exploring men's and women's attitudes to chlamydia testing, important differences were revealed by participants: women felt anxious about their future reproductive health, feared stigmatisation, and blamed themselves for contracting chlamydia, while men reported being less concerned, and were unwilling to disclose their infection to sexual partners. Some men attributed blame to their partners and delayed seeking care.
Many healthcare professionals remain untrained, unsupported and lack the clinical confidence to examine or offer a young man a chlamydia test - a far less complicated and invasive procedure than a speculum examination, yet one which remains shrouded in mystery (Robertson and Williams, 2005).
Controlling chlamydia and including men
Fenton et al (2000) argue that heterosexual men are ignored when it comes to the campaign to reduce chlamydia. In their view, the current strategy is essentially a secondary prevention strategy for women because primary prevention in this group is best achieved by reducing the prevalence of infection in men.
Published results from the first phase of the NCSP demonstrate that men are equally, if not more, at risk of infection than women: clamydia positivity in those screened in non-GUM settings was 10.1% in women and 13.3% in men (LaMontagne et al, 2004).
The justification for not targeting men in the NCSP is based on a pragmatic and now arguably obsolete rationale. For instance, because opportunities for screening asymptomatic men are limited by the fact that men do not routinely seek preventive health care, testing men in clinical settings is less feasible.
However, the 1998 general practice survey (Airey et al, 1999) found that 71% of men aged 18-44 had visited a GP in the past year, which offers a huge potential for offering screening. Furthermore, male attendance at contraception clinics is increasing, and the biggest obstacle to screening men - the need to obtain a urethral swab - has now been removed.
The availability of urine-based tests has the potential for encouraging young men to seek screening in primary care and in non-clinical settings, such as shopping centres, prisons, work places, police and army training schools, colleges and social venues.
The NCSP has shown that screening large numbers of young people in primary care and non-clinical settings is feasible and highly acceptable. There has been more than a three-fold increase in the numbers screened in the second year of the programme to a total of 78,000 (LaMontagne et al, 2004). Nevertheless, the population coverage, currently at 0.6% of the eligible female population and 0.3% of eligible men, must be increased substantially if the government's stated aim of full coverage across the country by March 2007 is to be achieved.
Chlamydia screening is now, for the first time, a key component of local delivery plans for primary care trusts, with further opportunities and remittance in the new GMS contract for the provision of enhanced sexual health services in primary care.
Since November last year, Boots the chemists have provided free chlamydia screening in high street pharmacies for 16- to 24-year-olds across London, so making screening easy and treatment services accessible, as well as forming a pilot to evaluate community pharmacies as alternative sites for screening.
The control of chlamydia is an important public health issue. If the NCSP is to be successful, efforts to control chlamydia must include men as well as women.