'Covid-19 may have devastating effects on Central Nervous System'

'Covid-19 may have devastating effects on Central Nervous System'

New Delhi: Scientists at the Indian Institute of Technology (IIT), Jodhpur, have explored the neuro-invasive nature of novel coronavirus highlighting that loss of smell and taste of infected patients makes the entire Central Nervous System (CNS) and underlying structures in the brain more prone to the viral infection with devastating effects.

Dr. Surajit Ghosh and his team have pointed out that SARS-CoV-2 is known to interact with a specific human receptor ‘hACE2’ (human angiotensin-converting enzyme-2) which also happens to be entry point of the virus and has an almost ubiquitous presence in most human organs ranging from lung parenchyma to nasal mucosa. The brain is also known to express this receptor.

“The loss of smell or taste points to the fact that nose and mouth are key entry points of the virus, which then may slowly make way to the olfactory bulb using neurons of the olfactory mucosa. The olfactory bulb located in the fore-brain is the structure that is chiefly responsible for the sense of smell. This explains the loss of smell associated with many asymptomatic carriers of Covid-19 and may expose the CNS to the viral infection,” the study said.

The paper accepted in ACS Chemical Neuroscience and supported by Science & Engineering Research Board (SERB), a statutory body under the Department of Science & Technology (DST), has suggested probable therapeutic strategies on the basis of understanding neurological manifestations of Covid-19.

The paper recounts a recently conducted study on the brain scans (CT and MRI) of a patient infected by Covid-19 virus that shows a rare encephalopathy called ANE, which leads to brain dysfunction with seizures and mental disorientation. It indicates that in the presence of human ACE2 receptors in CNS, the brain may be infected by the virus through the olfactory bulbs and also through other peripheral nerve terminals or simply blood circulation and may breach the blood-brain barrier to innervate and attack CNS. The scientists said it may completely destroy medulla oblongata of the hind-brain, which regulates breathing, heart, and blood vessel function.

The study rings warning bells to asymptomatic carriers of Covid-19 with anosmia (loss of smell) and ageusia (loss of taste) to self-quarantine themselves as soon as they feel these symptoms and consult specialized nephrologists before they turn into carriers. It also suggests brain autopsies of Covid-19 infected patients and analysis of their cerebrospinal fluid.

"The pathway of infection of SARS-CoV-2 and its impact on various organs is an important area that would also help with the future rational approaches for therapy. The neuro-invasive nature of the virus and its effects on the senses of smell and taste are thus interesting and useful areas of investigation,” said Professor Ashutosh Sharma, Secretary, DST.

The study found activities like smoking could increase the chances of contracting Covid-19 infection, attributing this to interactions and co-expression of the hACE2 receptor and the nicotinic receptor, which is stimulated on smoking.



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