Cold sores are icky. And they’re insidious. The raw, ugly blisters show up without notice and are unpreventable. Worse yet, once you’re infected with the virus that causes them, you’re stuck with it for good. But landmark research reported today by microbiologists at Duke University may offer the potential for a cure.

By age 40, nearly 90% of adults have been exposed to the herpes simplex virus-1 (HSV-1), which causes cold sores. People are usually infected as children, but many never have symptoms. For those who do, however, cold sores are a painful and permanent nuisance, always erupting in the same location, at the original site of infection on the lips or mouth. Once HSV-1 enters the body it hunkers down for life, most of the time hiding dormant in the cranial nerves near the spine. The virus can be triggered by outside stress, such as exposure to sunlight, a fever or emotional distress. After it’s active and a cold sore appears, it’s treatable with the drug acyclovir, marketed under the name Zovirax, which kills replicating HSV-1. But the mystery has been how to eliminate the virus while it’s hiding, before it produces unsightly symptoms.

Until now, research has generally concentrated on keeping HSV1 inactive — and preventing cold sores from ever showing up. But the Duke researchers took the opposite tack: figuring out precisely how to switch the virus from latency to its active stage. That’s important, says lead author Dr. Bryan Cullen, professor of molecular genetics and microbiology at Duke, “because unless you activate the virus, you can’t kill it.”

Cullen and his team were able to replicate the intricate process using lab mice. They started by identifying the tiniest components of the HSV-1 strain. In its latent stage, HSV-1 produces a single molecular product, called latency-associated transcript RNA, or LAT RNA. Unlike most messenger RNA, LAT RNA doesn’t produce proteins, so scientists have never been able to determine LAT RNA’s exact function. But by inserting the LAT RNA into mice, Cullen found that it breaks down into even smaller strands called microRNA. Researchers then discovered that it was the microRNA that blocked production of the protein that activates HSV-1. “So if there was a sufficient supply of microRNA, then the virus stayed latent,” Cullen says. “But under a high level of stress, the microRNA’s blocking mechanisms break down, thus triggering a cold sore.” The study, funded by the National Institutes of Health, will be published in the journal Nature this week.

Understanding how to override the microRNA could allow scientists to activate the virus and then kill it using acyclovir. “Once the virus sticks its head up over the fence, you whack it off for good,” Cullen says. “Yes, the person has to have one last cold sore, but it’d be worth it to most people to cure them forever.”

The theory is that by activating the virus, then preventing it from returning to hibernation, which is when researchers think it gains strength, it can be completely eradicated. Cullen believes that a drug could be developed to block the microRNA that suppress HSV-1 into latency; once it’s active, acyclovir can be used to destroy the virus permanently. Cullen suggests that this new research may also eventually be applied to other latent viruses, such as herpes simplex virus-2 (HSV-2), which causes genital herpes, or the chicken pox virus, which causes shingles in adults. Cullen warns that some patients, especially those suffering genital herpes, may have to take acyclovir on a regular basis (HSV-2 is a hardier virus), but for people with HSV-1, the virus could be eradicated with just one dose.

Cullen and his colleagues, as well as several biotech firms, are already investigating such treatments and how best to deliver them. “Are any of these viruses fatal?” Cullen says. “No. But there are a lot of people who’d be thrilled never to have a cold sore again.”

A collaborative study which included researchers from the Health Protection Agency (HPA) West Midlands and is published in the journal Sexually Transmitted Infections (STI), shows an increasing rate of sexual infections in people over 45 years in the West Midlands.

The study examined episodes of infection between 1996 and 2003 and found an upwards trend in the number of visits by over 45s attending Genitourinary Medicine (GUM) clinics for Sexually Transmitted Infections (STIs) in the West Midlands. In 1996, this age group comprised 3.9% of all clinic visits; by 2003, this had risen to 4.5%.

The study looked at regional data for the period 1996-2003 and focused on five STIs – chlamydia, genital herpes, genital warts, gonorrhoea and syphilis. 4445 STI episodes were reported among over 45s in this period. Overall, males and those aged 55-59 were significantly more likely to be affected.

Rates for all five STIs were significantly higher in 2003 compared to 1996, and the cumulative rate of infection more than doubled from 16.7 per 100, 000 of the population in 1996 to 36.3 per 100,000 of the population in 2003.

The most commonly diagnosed infection among over 45s was genital warts, accounting for almost half (45%) of the cases. Herpes was the next most common, affecting almost one in five (19%).

“Despite the increased political, public and professional recognition of the public health importance of STIs, and the documented increase in the number of visits to GUM clinics by over 45s, there have only been a few small scale studies addressing STIs in older age groups,” Dr Babatunde, Consultant Regional Epidemiologist with the Health Protection Agency West Midlands.

“The results of this study can be used by public health policy makers to improve sexual health programmes for older people,” he said. “Sexual health strategies have rightly focused on the under 25s but our results indicate that sexual risk-taking behaviour is not confined to young persons but is also an increasing trend in the over 45s” said Dr Olowokure. ”

Dr Olowokure added: “Older people are increasingly likely to be single or undergoing relationship changes and are less likely to consistently use condoms, perhaps because the risk of pregnancy no longer exists. Increased international travel, internet dating, new drugs to counter erectile dysfunction and overlapping sexual networks may also be factors. .These issues all warrant further exploration.

“Attitudes to sexual relationships are changing across the generations, and the increasing rate of infection seen in older age groups would indicate that they remain sexually active and at risk of sexually transmitted infections. It’s very important that health services and others recognize this and ensure that older age groups are not missing key ’safer sex’ messages.”

The HPA now plans to work with its partners to investigate the social and behavioural patterns that may lie behind these findings.

HPA Expert: Consultant Epidemiologist Dr Babatunde Olowokure is available for comment for both print and broadcast journalists

Notes

Summary of the findings of this study:

- This study provides evidence of significant increases in attendance at GUM clinics by older persons
- Current public health policy and sexual health progammes do not adequately cater for older persons
- Results indicate that sexual risk-taking behaviour is not confined to young persons but also occurs among older persons.
- There is a need for good quality qualitative and quantitative research to support effective planning and implementation of sexual health strategies aimed specifically at older persons.

More than one-fourth of adult New Yorkers — 26 percent, compared to the national average of 19 percent — are infected with HSV-2, the virus that causes genital herpes, the city’s Department of Health and Mental Hygiene announced on Monday. Officials said they were concerned about the prevalence of the condition because it facilitates the spread of H.I.V. and can also be transmitted to newborns, though such cases are rare.

The virus is sexually transmitted. Its symptoms include genital ulcers or sores, and it can lead to infection of the lining of the brain and of the brain itself newborns. Some people who have the virus, commonly abbreviated as HSV-2, do not show symptoms; up to some 30 percent of American adults have antibodies against the disease.

The new study found that the genital herpes virus was more common among women than men (36 percent versus 19 percent), among blacks than whites (49 percent versus 14 percent), and among men who have sex with men than those who don’t (32 percent versus 18 percent).

The study, published this month in the journal Sexually Transmitted Diseases, was the first measurement of New York City’s infection rate; the national rate has declined in recent years. The data came from the city’s Health and Nutrition Examination Survey, which was conducted in 2004 among a representative sample of New York City adults 20 or older. Of the 1,999 people enrolled in the survey, 1,784 were tested for HSV-2.

The Health Department received more than 65,000 reports of sexually transmitted infection in 2007 alone, and its rates of gonorrhea, chlamydia and infectious syphilis are above the national average. And the department reported last fall that H.I.V. infection is Increasing among young men who have sex with men .