Among the more disturbing news in November was the report from the Health Protection Agency (HPA) that the number of cases of HIV in the UK had jumped by nearly 20 per cent in the past year.

But UK sexual health for all categories of sexually transmitted disease is very poor indeed. Latest figures for all sexually transmitted infections (STIs), published in July, revealed that chlamydia ? the most common STI ? rose by 67 per cent in males and 33 per cent in females; gonorrhoea by eight per cent in males and 10 per cent in females; genital herpes by one per cent in males and four per cent in females; and genital warts by three per cent in males and one per cent in females.

Although HIV is the most serious STI, other infections can also cause severe health problems. If left untreated chlamydia is associated with pelvic inflammatory disease which can lead to infertility and even a potentially life-threatening ectopic pregnancy. Recent research has also pointed to the infection being implicated as a possible risk factor in the later development of ovarian cancer.

Although by no means all women infected go on to develop the disease, genital warts, particularly the HPV virus, is strongly implicated in the later development of cervical cancer.

Genital herpes (the Herpes Simplex 2 virus, or HSV-2), by comparison, is a much less serious condition. The first episode of infection ("primary") can be quite severe, with extremely painful blisters (especially on contact with urine) and inflammation at the site of infection, and is occasionally accompanied by urinary tract infection. Subsequent attacks ("recurrent GH") are likely to be mild, and the infected person will probably experience signs that an attack is pending (such as itching or burning in the genital area).

However, although there is no "cure" for the virus (infection is life-long), many of those infected will not go on to have another attack ? indeed many people may harbour the virus unknowingly and are asymptotic.

Treatment is available for those who have recurring outbreaks ? women may find that it is associated with fluctuations in their menstrual cycle ? and even then, the HPA say, "if the infection is left untreated, most people will eventually stop having recurrences".

In 2002, according to HPA figures, 18,388 men and women attended STD clinics in England, Wales and Northern Ireland with a first attack of GH. The rate of infection was highest among those aged 20-24.

It is estimated that 100 million people worldwide are infected ? including one in four Americans, and one in 10 of the UK population ? although the majority probably do not know that they carry the virus.

For the most part infection can be prevented by the use of condoms. A person with GH is most infectious during an outbreak when lesions (ulcers) are present, but GH can be transmitted at other times as the virus can be "shed" without any symptoms (although this is most likely to happen in the first year of contracting the infection).

On the whole ? although the stigma of the "label" of having GH after diagnosis can cause real mental distress ? GH is a relatively minor infection compared with other STIs (except in those with suppressed immune systems, and it has been implicated with facilitating HIV transmission).

However the disease is particularly dangerous if caught during pregnancy as it can cause "severe systemic disease in neonates", which can result in death. This scenario is, fortunately, still a rare one ? but given the average age of infection amongst women, it is a real concern.

The HSV-2 antibody prevalence in England and Wales, the HPA says, is approximately three per cent in men and five per cent in women. Among the five per cent of women, if the infection is dormant or recurrent, a pregnant woman will have her GH managed by the monitoring of her condition. Should, if she is unlucky, an outbreak be detected at the time of delivery, then the woman will be given a caesarean section (CS).

However, the HPA says it is best to assume that in most cases a "vaginal delivery should be anticipated".

The real concern arises amongst those women composing the five per cent testing positive for the antibody who are not aware that they carry the virus as they are either asymptomatic or because the signs of GH have not been specific (as they are in the majority of cases).

Guidelines recommend that all women should be asked at their first antenatal visit if they or their partner have ever had GH ? although this is infrequently done. Because of the widespread nature of GH infection, some health professionals recommend that all women who have been sexually active and have had unprotected sex with more than one partner ? and in particular those who have had multiple partners ? and are considering becoming pregnant, should be tested to see if they carry antibodies for the virus.

Nonetheless the Herpes Virus Association, www.herpes.org.uk, says that women who are infected before pregnancy will give birth normally. "This is because during the last few months of pregnancy, babies in the womb develop antibodies to all the infections ('childhood illnesses') that their mothers have previously caught (and have antibodies for)," the association says. "These protect the baby from infection during childbirth and for three to six months afterwards; longer when breastfed."

However, of more serious concern is a primary infection of GH contracted during pregnancy. In the first trimester of pregnancy this may trigger a miscarriage. If contracted in the later stages of pregnancy, it does not give time for protective antibodies to develop before birth. "If a true first episode is confirmed," says the HPA, "CS should be considered for all women, particularly those developing symptoms after 34 weeks of gestation, as the risk of viral shedding in labour is very high." Unfortunately CS for the prevention of neonatal herpes "has not been evaluated in randomised controlled trials and may not be completely protective against neonatal herpes". In the unfortunate event that a vaginal delivery was unavoidable, the HPA says that treatment with acyclovir (an anti-viral treatment) of mother and baby "may be indicated". Acyclovir is not currently recommended as a treatment during pregnancy itself.

Fortunately neo-natal infection of GH is still very rare indeed and, despite the prevalence of infection, current procedure and good practice for the monitoring of the health of pregnant women is still likely to identify those most at risk.