Experts have been expressing concerns over an increased possibility of how COVID-19, the illness caused by the new coronavirus, has been affecting the brain or the central nervous system.

In advanced cases, the virus may invade the brain via the olfactory nerve in the nasal cavity and damage the nerves that control respiration.

Québec-based Virologist Pierre Talbot said, “Doctors should be aware of this possibility. It may not be only pneumonia [killing patients], the virus could be infecting the brain.”

Researchers Yan-Chao Li, Wan-Zhu Bai, and Tsutomo Kashikawa of the Jilian University of China and RIKEN Brain Science found that coronavirus patients who were receiving intensive care in China could not breathe on their own and most of them showed neurological signs, such as headache, nausea, and vomiting.

Talbot agreed with the findings and said the virus could infect the neurons controlling breathing. He said, “This is credible, and it is a major observation.”

Microbiologist Stanley Pearlman from the University of Iowa said, “It is certainly plausible that this could be happening in a fraction of COVID-19 patients. Maybe the ones with the greatest severity of illness.”

Talbot and his team have been studying the effect of coronaviruses on the brain via the olfactory nerve for the last 25 years.

“Given our results with the human coronavirus causing common cold, I think we should not discard this possibility with the virus that causes COVID-19,” Talbot said.

Other strains of coronaviruses that caused Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) have also been associated with neurological implications. In fact, autopsy studies of patients with SARS and MERS found coronaviruses in their brains.

There is growing evidence that COVID-19 could also cause brain infection. In early March, a 56-year-old Chinese patient with coronavirus had neurological complications, which doctors described as “impaired consciousness.” The patient’s cerebral spinal fluid (CSF) examination diagnosed the condition called viral encephalitis, a brain inflammation that doctors attributed to the presence of the new coronavirus.

The novel coronavirus primarily attacks the lungs, causing pneumonia; however, the cases involving neurological implications would be more dreadful.

Recently, some patients reported anosmia (loss of the sense of smell), which could be an early symptom of COVID-19 if the virus invades the olfactory nerve and brain.

Talbot noted, “The lack of smell is often the first symptom of damage to the CNS. It can be the first symptom of diseases such as Parkinson’s and Alzheimer’s, so it suggests that viruses that can get to the brain and could cause a loss of smell as a consequence of the virus traveling through the olfactory nerve.” However, he cautioned that such reports are anecdotal for now and they should be monitored closely.