[Skybird]

https://www.bbc.com/future/article/2...ecades-to-come

Now scientists are keen to monitor whether the current pandemic will also trigger a higher rate of Parkinson's cases in decades to come.

"We don't know but we need to consider that this could become the case," says Patrik Brundin, a Parkinson's researcher at the Van Andel Institute, in Grand Rapids, Michigan. "There are several studies highlighting that people who have recovered from Covid often have long-term central nervous system deficits including loss of sense of smell and taste, brain fog, depression, and anxiety. The numbers are troubling."

While Sars-CoV-2 can invade brain tissue, the scientific jury remains open on whether it will contribute to neurodegenerative disease. Coronaviruses are generally known as "hit and run viruses", because they tend to cause fairly short disease, even if this proves deadly in some cases. In contrast, DNA viruses such as Epstein-Barr can linger permanently in the body and are more associated with long-term illness.

But there have been some indications in the past there might be more to coronaviruses than we perhaps suspect. In the 1990s, Canadian neurologist Stanley Fahn published a study which identified antibodies to the coronaviruses that cause the common cold in the cerebrospinal fluid of Parkinson's patients.

Over the past year, scientists like Brundin have been concerned by the emergence of a small handful of case studies describing patients who have developed what doctors term acute Parkinsonism – abnormalities such as tremors, muscle stiffness, and impaired speech – following Covid-19 infection. More research has found that some Covid-19 patients have disruptions in one of the body's most critical systems, known as the kynurenine pathway. This runs from the brain to the gut, and is used to produce a number of crucial amino acids required for brain health. But when it malfunctions, it can lead to the accumulation of toxins which are thought to play a role in Parkinson's disease.

Other neurologists, however, warn it is still far too early to draw any link between Covid-19 and Parkinson's.