reply to post by Melissa101
In a study offering tantalizing clues into the origins of a devastating and mysterious ailment, researchers concluded that people who survive a strain
of bird flu have a significantly greater risk of developing Parkinson's disease.
Published in this week's edition of The Proceedings of the National Academy of Sciences, the study by a team at St. Jude Children's Research
Hospital in Memphis found that mice infected with the A/Vietnam/1203/04 strain of the H5N1 avian influenza virus suffered neurological damage similar
to that associated with Parkinson's.
The researchers found that the virus, having replicated in the lungs, travels nerve pathways and attacks small groups of cells in the brain stem.
The infected mice developed tremors, slowness of movement and a general "pathology similar to what's seen in Parkinson's," said Dr. Richard
Smeyne, associate member of St. Jude's developmental neurobiology department and lead author of the study.
The study didn't suggest that the virus causes Parkinson's, only that it leaves survivors more susceptible to the disease -- and possibly other
The study is significant because it establishes that viruses could be "one environmental agent that can start the cascade leading to Parkinson's,"
the causes of which are unknown in 95 percent of cases, Smeyne said.
"This is the first study with very direct experimental evidence that a virus that is in the environment can lead to this pathology," he said.
According to the National Parkinson Foundation, about 60,000 new cases of the disease are diagnosed annually in the United States, adding to the
estimated 1.5 million Americans who already have it. Usually occurring after age 65, the disease strikes when dopamine-producing cells in certain
regions of the brain die, causing tremors, cognitive problems and various other symptoms.
Previous research has linked the disease to genetic and environmental factors. Just last month, for instance, a study by scientists at the University
of Texas Southwestern Medical Center was published showing that people with Parkinson's had relatively high levels of a certain pesticide in their
Haeman Jang, another of the St. Jude study's authors, said the research offers new insight as to how viruses can invade the central nervous
Scientists long have known that some viruses can cause neurological ailments. Survivors of the Spanish flu pandemic that began in 1918, for instance,
were found to be at greater risk of developing a type of encephalitis later on.
However, there's no evidence yet that the H1N1 swine flu virus, which has spread rapidly this year, is linked to any neurological problems,
St. Jude conducted the study because it is a World Health Organization Collaborating Center for Studies on the Ecology of Influenza in Animals and
(Tom Charlier is a reporter for The Commercial Appeal in Memphis, Tenn.)