Remember how viruses like HPV are known to cause some cancers, turns out they can also induce chronic neurodegenerative fatal diseases, such as Parkinson's and Alzheimer's. Scientists have found that the central nervous systems of people who have experienced severe cases of H5N1 Avian flu are affected by the virus.
In research, scientists sprayed a highly infectious form of H5N1 into the noses of several hundred mice; they noticed that the virus infects nerves in the gut and travels along the nerves and enters the mice's brains. They noticed that with the virus in the brain, the body continually mounts an immune response even after the main body infection has ended, which later causes the brain to suffer the loss of neurons and protein aggregation or clumping. These two abnormalities then caused tremors and loss of coordination, two common symptoms of Parkinsons and Alzheimer's.
Such damage, the claimed, can make flu patients more susceptible to even more brain damage in future cases of flu, especially in children.
Although there is no research to prove it, scientists claim that all flu viruses including the new H1N1 flu pandemic virus might be capable of causing encephalitis.