Billing it as a world first, a Japanese researcher said an acid produced in the mouth due to gum disease activates the virus that can lead to full-blown AIDS, Agence-France Presse reported.

The researcher said a group of bacteria that leads to periodontal disease not only poses a threat to teeth, but the entire body.

"They produce a large amount of butyric acid, which smells like socks you wore for a long time," said Kuniyasu Ochiai, professor who chairs the Microbiology Department at Tokyo-based Nihon University.

The acid, which can also be found in rancid butter, hinders a kind of enzyme called HDAC, which blocks HIV from developing, Ochiai said.

"Serious periodontal disease could lead to the development (of AIDS) among HIV-positive people... although the probability largely depends on individual physical strength," Ochiai said.

Previous research has shown that gum disease is linked to diabetes and heart disease but until now, it has not been linked to HIV.

Periodontal disease is an infection of the tissues that supports your teeth. The disease attacks just below the gum line where it causes the attachment of the tooth and it’s supporting tissues to break down, the American Dental Association said on its Web site.

The study will be published in the March issue of the monthly Journal of Immunology.

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