Kissing 'spreads cancer virus'

Kissing may spread a virus which causes cancer

Kissing may spread a virus thought to cause cancerous tumours, according to scientists.

The finding could mean the need to reconsider safe sex public health messages.

The scientists have uncovered evidence that kissing may be what spreads human herpes virus 8 (HHV-8) among men.

HHV-8 is the cause of Kaposi's sarcoma, a cancerous tumour that usually appears as a purplish raised blotches on the skin or in the mouth.

We found the virus in the mouth more often and in higher amounts than in genital secretions

Dr John Pauk, University of Washington

It can also form inside internal body cavities, such as the abdomen and chest.

The research was carried out by scientists at the University of Washington and the Fred Hutchinson Cancer Research Center in Seattle.

Kaposi's sarcoma has been recognised for centuries among people living in Southern Europe, the Middle East and Africa, but became more frequent in the United States and Western Europe in the early 1980s.

The cancer most often occurs in people with compromised or suppressed immune systems.

For that reason it is a common symptom among people suffering from Aids.

It is also found among people who have received organ transplants who must take drugs to suppress their immune system and reduce of rejection.

Chemotherapy

Kaposi's sarcoma can usually be treated effectively with chemotherapy, though occasionally, it can spread to internal organs and prove fatal.

HHV-8 was first linked to Kaposi's sarcoma in 1994 by researchers at Columbia University.

Kaposi's sarcoma takes the form of cancerous skin tumours

HHV-8 belongs to the family of human herpes viruses that include those responsible for oral and gential herpes and chicken pox.

Although previous studies had indicated that in the US HHV-8 was more common among people with many sexual partners, the exact mechanism of transmission remains unclear.

In addition, in Africa and in Southern Europe, the virus is found in children as well as adults, suggesting that non-sexual spread can occur.

Lead researcher Dr John Pauk said: "When we think of STDs, we traditionally think of infections which are spread through sexual contact.

"It turned out that HHV-8 has been very hard to find in genital secretions.

"One of the reasons people started looking at the mouth is because Kaposi's sarcoma often shows up first as lesions in the mouth.

"We found the virus in the mouth more often and in higher amounts than in genital secretions."

The scientists have also shown that HHV-8 reproduces itself in the cells lining the mouth.

Risk factors

Among men who have sex with men in Seattle, the virus was found in about 40% of the men with HIV infection and about 20% of men without HIV.

The study analysed 112 men who have sex with men and found the following increased the risk of HHV-8 infection:

• A history of sex with a partner who has Kaposi's sarcoma.
• A history of deep kissing - the exchange of saliva - with an HIV-positive partner.
• The use of amyl nitrite capsules (known as 'poppers') or inhaled nitrites to enhance sexual gratification - the reason for this is unclear.

Dr Anna Wald, director of the University of Washington's Virology Research Clinic, said the research could mean public health messages on safe sex might have to be re-considered.

She said: "Safer sex messages have focused on exposure to genital secretions.

"The issue that this paper raises is that kissing can also be a risk for a virus."

Simon Gregor, of the UK's Public Health Laboratory Service, said the different studies had come up with varying theories about how HHV-8 was transmitted.

He said: "At the moment the jury is out on how exactly the virus is transmitted."

The research is published in the New England Journal of Medicine.