What do we mean by Sexually Transmitted Diseases (referred to throughout the rest of this paper as STDs)? They are diseases which require direct contact to spread from one person to another (because the organisms survive poorly outside the human body) and which over the years have been shown by medical research to be predominantly, if not exclusively, transmitted by sexual contact. (NB. Don't assume that all genital tract infections are sexually acquired.) Over 40 STD infections have been described. It is important to realise that the unborn child may become infected either in the womb or during birth and congenitally and perinatally acquired infections can be serious.
It is estimated that each year 13 million Americans will acquire a STD1 or, to use the opening words of a speaker at a New York conference entitled The Health Status of American Children and Youth held in 1992, "During this 10-min presentation, at least 50 adolescents across the United States will acquire one or more sexually transmitted diseases. Some of these diseases can fortunately be treated and cured; however, other diseases will remain with these young people for the rest of their lives, causing dramatic physical and psychological repercussions2. The figures for Britain are incomplete because only STD clinics report their figures. Diagnoses made by doctors in other specialities are not recorded. Official returns from STD clinics for 1993 show 11,800 cases of gonorrhoea; 33,267 cases of chlamydia; 100,820 cases of non-specific genital infection and 25,500 cases of genital herpes3. A recent large survey reported that overall 8.3% of men and 5.6% of women reported visiting a STD clinic4. There was, not surprisingly, an association with age. The peak in men occurred in the age group 25-39 whilst in women it was age 16-24. There was also a large geographical variability with the highest incidence in the London area.
Whatever the source one clear fact that emerges is that the more sexual partners that you have the more likely you are to acquire a STD. The table below shows the results from the UK survey(4).
| Percentage reporting to STD clinic by number of partners | |||||||
|---|---|---|---|---|---|---|---|
| Number of sexual partners | 0 | 1 | 2 | 3-4 | 5-9 | 10+ | |
| Men | - hetrosexual | 0.9 | 1.7 | 2.8 | 3.8 | 7.8 | 20.2 |
| - homosexual | 7.4 | 20.3 | 15.1 | 33.9 | 44.3 | 67.3 | |
| Women | - hetrosexual | 0.5 | 1.3 | 2.4 | 6.1 | 12.2 | 26.7 |
| - homosexual | 5.3 | 27.9 | 16.9 | 32.7* | 26.6* | 0* | |
| *only small numbers in these groups | |||||||
It is equally important to recognise that not all infections cause symptoms, especially in women. Furthermore women are more susceptible to infection and are more likely to develop complications5.
A useful way of considering STDs is by the time course of their effects and complications (see table below)
| Major STD Microbial Agents and their Impact (Table taken from Ref 5) | |||
|---|---|---|---|
| Actute Disease | Pregnancy Associated Disease | Chronic Disease | |
| Gonorrhea | Urethritis Cervicitis Salpingitis | Prematurity Septic abortion Ophthalmia of newborn Post partum endometritis | Infertility Ectopic pregnancy |
| Chlamydia | Urethritis Cervicitis Salpingitis | Ophthalmia Pneumonia in baby Post partum endometritis | Infertility Ectopic pregnancy |
| Syphilis | Primary and secondary syphilis | Spontaneous abortion Stillbirth Congentital syphilis | Neurosyphilis Cardiovascular syphilis |
| HIV | Glandular fever-like illness | Prematurity Stillbirth Perinatal HIV | AIDS |
| Human Papilloma Virus | Genital warts | Laryngeal papillomatosis in child | Genital cancer |
| Herpes simplex type 2 | Genital ulcers | Neonatal herpes Prematurity | ?Genital cancer? |
| Hepatitis B | Acute hepatitis | Perinatal HBV | Chronic hepatitis Cirrhosis Liver cancer Vascilitis |
So let us look at some of these in more detail. Many, including adolescents, have heard of venereal disease but assume that they are all treatable with antibiotics. In many cases this is true, but what they forget, or are not told, is that many infections - especially the viruses - are not treatable. For instance an acute attack of genital herpes will subside, but then the virus can lay dormant only to reactivate later. [NB the herpes virus that causes cold sores (HSV type 1) is different from the virus that causes genital herpes (HSV type 2)]. They also forget that many infected individuals can be asymptomatic but the infection is causing permanent damage.
The psychological impact has been poorly addressed. A study of adolescents found those who got infected were noted to have a lower self-esteem as well as suffering depression, guilt and shame6. Another study found that 31 % of those attending a STD clinic were sufficiently anxious or depressed to warrant being classified as psychiatrically ill7. A study from South Australia found a higher level of 'abnormal illness behaviour' in patients with a STD which increased with the number of previous infections.8 In a fourth study one third of patients scored positively on the 'general health and illness behaviour questionnaire.' The scores from STD clinic patients were higher than any other group of patients except psychiatric in-patients, indicating the high degree of psychological distress associated with a venereal infection9.
In general the acute symptoms of a STD affect the genital tract. Gonorrhoea and chlamydia can both cause a discharge, but it important to recognise that infections, particularly in women, can be asymptomatic. In fact 70% of chlamydial infections in women, and 25% in men are without acute symptoms10. However, even if asymptomatic these organisms can spread higher up the genital tract to cause permanent damage. Gonorrhoea can be spread through the blood stream to infect joints and cause gonococcal arthritis.
Some individuals (related to their tissue type) are prone to a condition called 'Reiters syndrome' which consists of urethritis, arthritis and conjunctivitis. Many of these cases are related to STD (especially chlamydia) although it can also follow many non-sexual infections.
There are many types of the human papilloma virus. Type 1 causes the common skin warts - this type has nothing to do with sexually transmitted infections. However, types 6 and 11 cause genital warts, while types 16 and 18 are associated with cervical cancer (see later) and are sexually transmitted. The warts can be obvious to the naked eye or they can be 'flat warts' that are visible only under the microscope.
Genital herpes in the woman can be asymptomatic, but the initial infections are usually associated with ulcerating and often painful blisters both on the cervix and external genitalia. Reactivation is common with genital herpes.
Syphilis is rare in the UK, although the only official notifications are those that are diagnosed by STD clinics. In 1993 they reported 866 new attendances in the UK. However, there has been a dramatic rise in incidence in the USA (see later). The bacteria enter the body at the point of contact and rapidly spread throughout the body. After an incubation period of between 9 and 90 days a painless ulcer appears which spontaneously heals within 2-6 weeks (primary syphilis). There is a second period of about 6 weeks before the appearance of secondary syphilis, often seen as a skin rash. The disease can then remain latent for years before the appearance of tertiary syphilis that can affect the central nervous system, blood vessels etc. Syphilis is readily treated by penicillin.
Hepatitis B is a form of hepatitis that is spread like HIV, ie via infected blood and sexual contact. About 1400 new cases are diagnosed each year in the UK. Do not confuse Hepatitis B with other viruses causing hepatitis that are acquired in other ways. Worldwide, transmission of the virus from the mother to the baby is the most important mode of spread. (see later)
By the end of August 1994, there were 22091 known HIV infected patients in the UK. 9290 have developed full-blown AIDS, of which 6283 have already died. 13679 acquired their infection through homosexual contact; 3524 - heterosexual contact; 2588 - IV drug abuse; 1373 - contaminated blood products; 927 - infected by unknown source11. It has now been recognised that the presence of other STDs make it easier to pass HIV from one person to another, with the risk of transmission of HIV being reported as two to nine times higher12.
So that I cannot be accused of being over-dramatic in the way I present the various problems associated with pregnancy, I would like to quote from the introduction of a medical article on the subject1. "The offspring of these women (ie with STDs) are also in jeopardy. Maternal STDs can result in conjunctivitis, pneumonia, laryngeal papillomas, liver disease, neurologic disease and even death for the exposed fetus. In communities endemic for STDs, more new-borns will die of congenitally acquired infections than die of all causes of infant mortality combined at average American Hospitals. It is clearly in the public interest to devise and implement strategies to protect mothers and children from the many risks associated with STDs'."
If gonorrhoea is acquired before the 12th week of pregnancy there is a risk of the infection spreading to the tubes to cause acute salpingitis. Reactivation of prior salpingitis can also occur and result in an ovarian/tubal abscess that may be more difficult to diagnose in pregnancy. Disseminated infection is also more common in pregnancy especially in the later stages13. Intrauterine infection of the fetus does not occur. However in early pregnancy gonorrhoea is associated with spontaneous septic abortion and infection after surgical abortion. Later in pregnancy it is associated with premature rupture of the membranes and placental infection. The most common complication is infection of the baby as it passes through the birth canal. This can result in genital infection of the baby but more commonly it presents as a conjunctival eye infection within 2-3 days. This is usually recognised and treated, but untreated this can cause perforation of the cornea with infection of the whole eye and disseminated infection of the baby.
This is now the most common STD in western society, with surveys reporting between 2 and 27% of pregnant women having active infection and 20-40% of pregnant women have positive antibody tests1 (evidence of previous infection). If the woman has active infection then the baby has a 50% chance of picking up the infection during birth, with a 40% risk of developing conjunctivitis and 20% risk of developing pneumonitis. Although the lung infection is not life threatening, it can be protracted and is associated with a higher prevalence of childhood respiratory disease14. Symptoms of both the eye and lung infections can be delayed for up to 6-months after birth15! In one small prospective study of 268 pregnant women, the babies of 6 of the 18 infected mothers died (33% perinatal mortality) compared to only 1 of 250 non-infected women16. In this same study 5 of the 18 (28%) infected mothers delivered prematurely compared with 6% of uninfected mothers. Prematurity and low birth weight is now well recognised in pregnant women with chlamydial infection.
Syphilis is rare in the UK and all antenatal clinics routinely test for syphilis. However, there has been a dramatic increase in incidence in syphilis in the USA, so we should not be complacent in this country. Primary and secondary syphilis in the mother often results in congenital syphilis of the fetus, which is associated with a 50% mortality. In the USA taken as a whole, there were 4.3 cases of congenital syphilis per 100,000 live births in 1982. In 1991 this has risen to 107 cases per 100,000 births. However there are pockets with a much higher incidence. Washington DC reported 2086.7 cases per 100,000 births (ie 2% of babies were born with congenital syphilis!!) and New York 1027.4 cases per 100,000 births17.
In the UK there is no official register of HIV in pregnancy. However the Royal College of Obstetricians and Gynaecologists together with the Institute of Child Health, has set up a voluntary register. Between June 1989 and May 1994 a total of 695 pregnancies in HIV positive women were reported. By July 31st 1994 the register was aware of 750 children born to HIV positive mothers. 274 of these are known to be infected by HIV; 269 are unaffected; it is still too early to determine the HIV status of the remaining 207 babies18. [NB It is invalid to calculate the transmission rate of HIV in pregnancy from these figures because in a proportion of the cases the HIV status of the mother only became apparent after the babies were diagnosed as suffering from AIDS.) Recent studies have shown that about 20% of babies born to HIV infected women will be infected. There are two patterns of disease progression in children infected during pregnancy. About 20% of infected children develop AIDS in the first year of life, with slower progression in the remaining children19.
Pregnancy is associated with a more rapid growth of genital warts. Treatment of the warts is difficult in pregnancy because a commonly used treatments (podophyllin) is teratogenic (ie can cause fetal malformation). The baby can pick up the virus during delivery and although for most this does not appear to cause a problem, in a small number of cases the virus infects the lining of the larynx causing laryngeal papiliomatosis. This is a condition where large bulky warts grow in the larynx which obstruct the airway, necessitating repeated operations to remove the warts. NB Despite the high incidence of HPV infection, laryngeal papillomatosis is rare.
Genital herpes infection in pregnancy, especially initial attacks, is associated with spontaneous abortion, preterm delivery and intrauterine and neonatal infection. Transmission of the virus to the fetus, via the placenta, is rare but when it does occur it is associated with brain damage and also infection of the retina of the eye. The most important complication is infection of the baby during delivery. If active herpes infection is present, then the obstetrician will deliver the baby by Caesarean, because of the devastating effect of neonatal herpes. 40% of babies born vaginally during active herpes infection will get infected. The infection becomes apparent between 1-3 weeks after birth with lethargy, irritability and poor feeding. Within 24hrs there is rapid progression with involvement of the liver, adrenal glands, lungs and brain. One third of the babies develop the typical painful blisters in the mouth or skin. Because of the brain infection the baby often suffers fits, coma, paralysis, meningitis and encephalitis. Up to 80% of infected babies will die or suffer serious brain damage.
Most adults who get infected with hepatitis B develop acute hepatitis; only 10% become chronic carriers. However, the baby who gets infected suffers no acute symptoms but almost invariably becomes a chronic carrier. Many years later in adulthood, that person can develop cirrhosis and liver cancer. Hepatitis B acquired at birth is the leading cause of liver cancer worldwide.
Infertility, particularly tubal infertility (ie blocked tubes) and ectopic pregnancies are becoming more common. There are many causes for blocked tubes (eg severe appendicitis) but unequivocally STDs have been an important factor. Sometimes the women give a clear history of pelvic inflammatory disease, but more commonly they report no such symptoms, yet the doctors find scarred Fallopian tubes. In these cases doctors call this atypical (or covert) pelvic inflammatory disease, because the woman did not have the typical symptoms of the disease. There is an association between infertility and nearly all of the different STDs. However individuals may be infected by more than one infection and so it is not surprising that the strongest correlation comes when the data is analysed by the number of previous sexual partners. In one large study involving seven different institutions in Canada and the USA, doctors compared women with tubal infertility (ie blocked tubes) with fertile women delivering babies at the same hospital. Among the questions asked were details about the numbers of sexual partners20. This data is shown in Table 3.
| Tubal infertility and Number of partners | ||
|---|---|---|
| 1 or 2 partners | 3+ partner | |
| Fertile women | 64.80% | 35.20% |
| Infertile (Covert PID) | 48.70% | 51.30% |
| Infertile (Overt PID) | 35.60% | 64.40% |
| Table 3 | ||
Overt PID means that the women described typical symptoms of pelvic infection; Covert PID means the women did not describe any symptoms of pelvic infection, yet investigations showed evidence of such infection.
| Tubal Infertility and Number of Partners | |||
|---|---|---|---|
| No partners | 1 | 2-5 | 6+ |
| Fertile Women | 44.2% | 36.7% | 19.1% |
| Tubal Infertility | 25.8% | 42.4% | 31.8% |
| Table 4 | |||
An almost identical set of figures is presented by another similar study (table 4)21
A similar trend was found in a study of women with ectopic pregnancy22.
It can be seen from these figures that those women with tubal infertility are more likely to admit to a greater numbers of sexual partners.
For completeness here are the details of two studies looking at the association of chlamydial infection and tubal infertility. One study from Bristol found 73% of women with tubal infertility had antibodies to chlamydia (ie evidence of previous infection) compared with 34% of infertile women with normal tubes23. A similar study from Finland found 46% of women with tubal infertility had chlamydial antibodies compared to 7% of infertile women with normal tubes24.
One infertility clinic reported that 14% of its cases of infertility were due to tubal damage, most likely related to previously acquired STDs25.
In summary, data from many studies show that the greater the number of sexual partners a woman has, the greater her chance of catching a venereal disease and, even if asymptomatic, the greater the risk of later infertility and ectopic pregnancy.
Not surprisingly the UK survey found that the number of sexual partners was the dominant factor for the probability that a woman has had an abortion(4).
| Relationship between number of partners and abortion | |||||
|---|---|---|---|---|---|
| Number of partners | 1 | 2 | 3-4 | 5-9 | 10+ |
| Percent having abortions | 6.0% | 9.8% | 16.5% | 23.0% | 34.4% |
| Abortion in last 5yrs | 2.6% | 8.7% | 12.3% | 15.7% | 33.7% |
Population studies of cervical cancer have clearly shown two important risk factors. Young age at first intercourse and the number of sexual partners. This is an associated with infection by the human papilloma virus (HPV), especially type 16. HPV 16 is not "the cause" of cervical cancer, since many women are infected by the virus but only a small number develop the disease, however it is an important factor. Cervical smears should pick up pre-cancerous changes and currently many laboratories are reporting up to 10% of the smears as abnormal. Many doctors believe that the screening programme has prevented a massive explosion of cervical cancer. The age of first intercourse is important because during adolescence the cervix is undergoing important changes, and it appears that if the HPV virus infects immature cells, it is more likely to initiate the precancerous changes.
Women should also be aware of their partner's sexual history. A study from India of women showing pre-cancerous changes on their cervix, but who had only a single lifetime sexual partner (their husband) showed that the sexual history of the man is crucial26. Premarital relations by the husband increased the woman's risk by 190%; Extramarital relations by 270%; both pre and extramarital relations increased the risk of the woman developing precancerous changes in her cervix by 690%! The risk increased if the husband had 3 or more partners or had a documented STD. [NB The cause of any cancer is multifactorial and so there will be cases of cervical cancer in women who are virgins.]
The appearance of AIDS, with its uniformly fatal outcome, has focused attention on the problem of STDs. It is obvious from the medical data that the only way to be sure of preventing AIDS and other STDs is by lifelong monogamous sexual relationships. (All blood products are now tested for HIV, so accidental non-sexual transmission will be very rare.)
People who attempt to promote the idea of sexual abstinence are often branded as unrealistic, (or religious fundamentalists!) The establishment has come up with the concept of "Safer sex" (originally called safe sex). But surveys of the public have shown that only one aspect of this idea is known - "use a condom." In fact there are five a) Use a condom, b) Reduce the number of partners c) Know the sexual history of your partner d) Choose your partner carefully and avoid a high risk partner, ie intravenous drug abuser or man who has had homosexual partners. e) Avoid certain sexual practices eg. anal intercourse.
But are these realistic aims? A survey of 9000 Swedish adolescents showed that 99% knew the claim that a condom was the best protection against STD27, but despite this only 11% used a condom every time, 17% had caught an STD, and 9% had been or had made somebody pregnant. There is a plethora of studies to show that outside stable relationships condom use is inconsistent. A recent study on the transmission of HIV between heterosexual couples has revealed that the same is also true in cases where a high risk is known and there is a stable relationship. The multicentre study, involving 10 European AIDS units, looked at the transmission of HIV in couples in a stable heterosexual relationship where only one partner was HIV positive. All these couples were aware of the problems and were counselled about "safe sexual practices" every 6 months28. Only 49% consistently used a condom (none got infected), with the remainder being equally divided between using condoms about half the time and very rarely/never (12.7% became infected). 17% of those not using condoms continued to have unprotected anal sex (27.8% of these women became infected).
But is the condom really effective as a protection against HIV and other STDs? Condoms are certainly promoted as such, and I am sure the above quoted study will be used as evidence to support it. But in that study only 124 couples used condoms consistently, the median follow-up period was only 2 years and the couples reported reduced sexual activity. However a review of the world medical literature shows that there is little solid evidence to support the claim that condoms are effective29. The "best" studies suggest a possible 40% reduction in the risk of contracting a STD, with one study showing no benefit at all! The author concludes his review by saying that when patients now ask whether condoms are effective he replies "I would say that they help to reduce the risk; that they do not prevent all STDs all of the time; and that other measures, such as limiting number of partners and getting screened for STDs, are at least as important(29)."
Is the money being spent on AIDS (and STD) prevention programs working? In 1990 the Centre for Diseases Control in USA spent $204 million on HIV prevention programs, of which half was for counselling and testing. One such centre in Miami carried out an audit of patients who had received an HIV test. All were counselled both before and after the HIV test and instructed on methods of "safer sex." They then looked at the number diagnosed with any STD in the 6 months before the test and compared it with the 6 months after the test. In those who tested HIV positive there was a 12% reduction in STDs in the 6 months after the test, but a 106% increase in those who tested HIV negative30!
It appears that the so-called professional advice is not being reflected in practice, and those advocating abstinence can justifiably criticise those promoting "safe sex" education to the young. As a Swedish author wrote(27) - "Society today allows sex 'as long as you are in love' which is often interpreted as meaning 'as soon as you are in love': sexual intercourse today often marks the start of a relationship rather than, as some decades ago, the confirmation of an established relationship. These attitudes of adult society are reflected in the behaviour of young people. In general, adolescents are faithful to one partner at a time but their time perspectives are short and this, combined with coitus early in a relationship, results in each having high number of partners. This creates the conditions for the spread of STDs."
Most of the STD prevention campaigns have been based on social psychology theories - with such grand sounding names as the 'health belief model'; 'theory of reasoned action'; 'protection-motivation theory'. But people have now began to realise that these theories apply to 'adult' thinking and do not apply to adolescent psychology. Adolescents are in a transition between what is called "concrete operational reasoning' and the adult "formal operational thinking"(6) So it is not surprising that current secular education methods are failing to curb the increase in either STDs or teenage pregnancies.
In addition there are some very important facts that many are ignoring. One of the effects of the hormones of the contraceptive pill is to enhance the acquisition of chlamydia infection and the presence of a STD enhances the transmission and progression of HIV infection31. How many young girls taking the pill to avoid pregnancy know this?
Let us recognise that adolescents will not always follow advice given to them, but let us at least continue to give them the truth about the dangers of promiscuous sex, rather than lead them into a false sense of security. The educational experts argue that 'frightening' people by quoting the dangers of an action does not work; a more effective method is the promotion of a positive role model. Regardless of the methods people use, I hope this paper will allow informed discussion on this topic to take place.
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