Covid-19: Australian researchers fear a "silent wave" of neurological disorders
An Australian study published in the Journal of Parkinson Disease indicates that the neurological disorders that follow the disease may become more common after the pandemic.
Since the discovery of Covid-19 in December 2019, scientists have continued to discover new elements. More or less worrisome neurological symptoms (confusion, loss of orientation, unusual agitation) have already been identified, and researchers are now interested in the neurotropic potential of SARS-CoV-2.
In fact, coronaviruses are known to be neurotropic viruses, capable of infecting cells of the nervous system and causing side effects such as anosmia. Therefore, a team of Australian scientists from the Florey Institute for Neuroscience and Mental Health has been interested in the neurological consequences of Covid-19 in the triggering of neurodegenerative diseases (in particular, Parkinsons disease and parkinsonian syndromes).
According to their findings, published in the Journal of Parkinsons Disease, a new epidemic wave could soon occur. It would not be a resurgence of coronavirus infections, but a subsequent rise in neurodegenerative diseases.
Inflammation of neurons could trigger Parkinsons disease
Chronic neuroinflammation potentially related to SARS-CoV-2 may play a role in the process responsible for the onset and development of Parkinsons disease / Parkinsons syndromes, scientists say.
The origin of Parkinsons disease is not yet well identified, but according to Kevin Barnham of the Florey Institute for Neuroscience and Mental Health: "One of the causes that triggers Parkinsons disease is inflammation. Once inflammation enters the brain , triggers a cascade of events that can ultimately lead to Parkinsons disease. SARS-CoV-2 appears to help stimulate this inflammation. "
To support their hypothesis, the researchers evoke the Spanish flu epidemic. "The first link between viruses and parkinsonism comes from the possible relationship between encephalitis lethargica and the Spanish flu of 1918. In its acute form, encephalitis lethargica exhibited annual peaks, mainly in winter, of different size and severity, which were more frequent in the early 1920s, "they state in their review article.
"We can learn from the neurological consequences that followed the Spanish influenza pandemic in 1918, where the risk of developing Parkinsons disease doubled or tripled. When the world population was again affected by a viral pandemic, it seems important to us to keep in mind account for the potential increase in neurological diseases on a global scale ”.
Preparing for a "silent third wave" of the Covid-19 pandemic
Many patients considered cured continue to suffer from fatigue, shortness of breath, but also sometimes anosmia. However, we know that in people with Parkinsons disease, loss of smell can appear 10 years before the onset of physical symptoms.
"We believe that anosmia is a new way of detecting early a person at risk of developing Parkinsons disease. Based on the knowledge that loss of smell is present in about 90% of people in the early stages of Parkinsons disease and a decade before motor symptoms, we feel we are on the right track, "Leah Beauchamp, a researcher at the Florey Institute for Neuroscience and Mental Health, said in a statement.
Therefore, in the long term, this persistent Covid-19 symptom could be associated with a deterioration of Parkinsons in people who are already ill or with the appearance of neurological disorders associated with Parkinsons and Parkinsonian syndromes. "The high prevalence of anosmia combined with the suspicion of a link between an association of encephalitis lethargic type with a historical influenza pandemic raises the question whether history is repeating itself," note the researchers, acknowledging, however, that a further investigation is still needed.
"An accurate understanding of the incidence of neurological complications from Covid-19 requires long-term monitoring of post-remission sequelae and a strategic health policy to ensure that health systems around the world are prepared for a third wave. of the virus. in the form of parkinsonism ", conclude the authors.