WASHINGTON (Reuters) - Researchers said on Tuesday they might be able to explain why herpes could cause Alzheimer's disease and that their findings might lead to treatments or even a way to prevent the disease.

They said the virus, which causes common cold sores, looks like a protein called beta-amyloid, which is blamed for helping to cause messy tangles of dead cells in the brains of Alzheimer's patients.

``What's unique about our finding is that it points to a way in which herpes can be acting,'' Frank LaFerla of the University of California Irvine, a dementia expert who led the study, said in a statement.

Writing in the journal Biochemistry, which is published by the American Chemical Society, LaFerla and colleagues said they created a synthetic protein that resembles herpes simplex-1 virus. They did a genetic sequence of their protein and found two-thirds of it was identical to beta-amyloid.

In the laboratory it killed neurons just like beta-amyloid does and formed them into the ``tangles'' that characterize the disease.

Nearly everyone has been exposed to herpes, but it causes cold sores in only some of them. An even smaller percentage get Alzheimer's and it is known there are genetic and other influences.

``I think researchers will continue to find new factors associated with Alzheimer's disease,'' LaFerla said. But the researchers think their study can help fill one piece of the puzzle.