http://www.telegraph.co.uk/science/science-news/6004728/Pathogenic-flu-increases-risk-of-Parkinsons-disease.html
A team led by Prof Richard Smeyne, a neurobiologist at St Jude Children's Research Hospital in Memphis, found that the bird flu virus that can enter the brain and cause damaging changes.
The study provides evidence for the long-held suspicion that viruses can increase the risk of developing certain severe conditions that appear unrelated to the original infection - even decades later.
The researchers found that a variety of the H5N1 bird flu virus was able to enter the brains of mice and cause several of the fundamental characteristics of Parkinson's disease including tremors, movement disorders and the loss of brain cells.
This cell loss was insufficient on its own to cause Parkinson's, because the mice's immune systems could clear the virus from the brain, but their immune systems were left in a chronically activated state.
This activation later led to the build-up of proteins in the brain that characterise diseases such as Parkinson's and Alzheimer's.
