DR THOMAS STUTTAFORD

A Herpes caused near-panic when the revolutionaries of the 1960s discovered that there was a sexually transmitted disease that couldn't be cured or treated effectively. It seemed that an inflamed itchy skin that within 24 hours produced a crop of small blisters was retribution from the gods for the pleasures of less-inhibited sex.

Aids drove news stories about herpes off the front pages. Aids, potentially lethal if untreated, was new to human beings and to Europe, whereas doctors had known about the two herpes viruses, types 1 and 2, for generations. They are arguably second only to the common cold as a cause of human viral infections.

Fortunately, herpes is not a big deal for most people - and if the herpes is confined to your girlfriend's genitalia, you are unlikely to catch it from kissing her. Ninety-five per cent of adults at some time of their lives, and 60 per cent of children by the age of 5, have been infected. Type 1 usually causes cold sores around the lips and mouth; type 2 usually attacks the genital organs, perineum or perianal area. But either type can affect either area.

The severity of attacks varies enormously. They usually start within four or five days of sex with an infected contact and may be so trivial - no more than a pink patch or an itchy spot - that the sufferer is unaware of its significance until a new partner develops sores. Or they may result in extensive painful ulceration. Most people develop a resistance once they have had an attack, but a minority continue to have recurrent bouts that are progressively less severe.

Tracing an attack's origins may be difficult as the virus can be dormant for years until the patient's immune system is impaired and troublesome symptoms recur. It is not always justified to assume that herpes has been contracted from a current partner; it may be a recurrence of a patient's own dormant infection.

The good news is that herpes doesn't have to be a painful nuisance, even if your immune system makes you liable to frequent attacks. Antiviral agents, which have been available for years, are remarkably effective. They can be used to treat an acute attack or, if normal life is disrupted by frequent bouts, taken in relatively small, regular doses.

As I've said, if your girlfriend's herpes is confined to her genitalia, kissing is unlikely to spread any infection, but oral sex is risky if you haven't any resistance to her type of herpes. There is a good chance that, unknowingly, you have had herpes types 1 and 2 before and are not susceptible to them.

Various factors, including exposure to too much sun - especially if there's a drying wind as well - other medical problems, or continuing emotional strain or overtiredness, may cause trouble. I always used to recommend that my patients with a history of herpes took the appropriate antivirals if they went for a holiday involving sun, sea and sand, or if they went skiing and were exposed to sun and snow.

Many patients with dormant herpes find that it is reactivated with a new sexual partner; the combination of excitement, emotional tension and the rough and tumble triggered by initial lust is too much for their immune system.

Dr Thomas Stuttaford, The Times doctor, spent many years working in a genitourinary clinic

SUZI GODSON

A Worrying about contracting genital herpes through kissing someone you have already had sex with is a bit like shutting the stable door after the horse has bolted.

Condoms don't provide 100 per cent protection against any sexually transmitted diseases and the widely held belief that herpes can be transmitted only during an outbreak means that many couples use condoms only when the infected person shows symptoms.

This is a mistake because new research from the University of Washington, published in The New England Journal of Medicine, has found that asymptomatic people are just as infectious as those who have the symptoms. It is estimated that only one in five infected people knows that he or she is carrying the virus. In the Washington study, for example, scientists found 53 people who tested positive for type 2 herpes were unaware that they had it. And more than four out of five of those cases were infectious.Both type 1 and type 2 herpes look identical under the microscope, and either can infect the mouth or genitals.

During an outbreak some people feel generally unwell and experience painful blisters, ulcers or crusts in the genital area and the buttocks. After initial infection, genital herpes lurks without symptoms in nerves at the base of the spinal cord and it is only if the disease travels along the nerves to the skin that symptoms reappear. Some people have one outbreak and never have another, but others, as the Washington study demonstrates, never experience any symptoms in the first place.

The infection is almost impossible to contain. Scientists believe that most genital herpes is acquired from a person with no known history of infection and caution that the spread of the disease is likely to continue unabated unless everybody who carries the virus know that they are.

One in four Americans has herpes and although the figures are lower here, between 1997 and 2006 the number of reported infections rose by 31 per cent.

It would help if men took sexual health a little more seriously. A MORI poll in 2000 revealed that only half of the men polled knew that a genitourinary medicine clinic treated sexually transmitted infections; 6 per cent thought it treated elderly people; and 13 per cent that it tackled gum disease.

If you get tested - as you should - and find that you have the virus, the good news is that you cannot be reinfected. Living with herpes is indeed a pain but it is not the end of the world. Condoms with a spermicide provide good protection and outbreaks can be treated with acyclovir, a drug that eases symptoms, speeds healing and, in some users, helps to prevent recurrent attacks.

Relationships do become more complicated. A study by the American Social Health Association found that 18 per cent of herpes sufferers blame their divorce or other break-up on the disease.

And the temptation for herpes sufferers who are symptom-free to avoid sharing their condition with new partners must be enormous. That your girlfriend was honourable enough to tell you in advance is commendable.

Suzi Godson is author of The Sex Book (Cassell, £16.99) and The Body Bible (Penguin, £16.99)

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