The symptoms suggest SARS-CoV-2 might infect neurons, raising questions about whether there could be effects on the brain that play a role in patients’ deaths, but the data are preliminary.


Nearly two weeks ago, Alessandro Laurenzi, a biologist working as a consultant in Bologna, Italy, was mowing the grass in his garden when a friend stopped him and said the mower reeked of fuel. “I couldn’t smell anything at all,” he tells The Scientist. That was in the morning. A few hours later, he went to have lunch and realized he couldn’t smell the food he was about to eat and when he took a bite, he couldn’t taste it either. Within a few days, he developed symptoms of COVID-19 and called his doctor to ask if he could get tested. Because his symptoms were mild, Laurenzi says, his doctor said no.

Laurenzi had heard anecdotally that many COVID-19 patients in Italy suffered from a loss of smell, so he started reading all the scientific papers he could find to see if his anosmia and ageusia would ever abate. One of the papers, a review published March 13, mentioned that SARS-CoV-2, like other coronaviruses such as SARS-CoV and MERS-CoV, could target the central nervous system, possibly infecting neurons in the nasal passage and disrupting the senses of smell and taste. 

Reading this, Laurenzi immediately reached out to the corresponding author, Abdul Mannan Baig, a researcher at Aga Khan University in Pakistan, and asked if his symptoms were reversible. The evidence, Mannan told Laurenzi and reiterated to The Scientist, indicates they will abate, possibly because the loss of sense is caused by inflammation in the area as the body fights the virus, so those symptoms could disappear in seven to 14 days. “Let’s hope so,” Laurenzi tells The Scientist.

Documenting such peculiar symptoms is important, Mannan tells The Scientist, because the loss of smell and taste could be an early warning sign of SARS-CoV-2 infection. Based on the literature, British ear, nose, and throat doctors have now called for adults who lost those senses to quarantine themselves in an attempt to tamp down the spread of the disease, The New York Times reports. The symptoms, Mannan adds, also suggest that the virus has the ability to invade the central nervous system, which could cause neurological damage and possibly play a role in patients dying from COVID-19.

This is something to keep a careful eye on. There’s been some intriguing observations in previous studies on viruses, including coronaviruses, to show that they have the capacity to enter the nervous system.” It’s important that this be considered for SARS-CoV-2 and for “people to do the experiments, including autopsies, to look for signs of this damage.”
Matthew Anderson, a neuropathologist at Beth Israel Deaconess Medical Center in Boston. “

Mannan emphasizes that the neurological data on SARS-CoV-2, though preliminary, could be important for doctors deciding how to treat patients. Asking about neurological symptoms—loss of taste or smell, twitching, seizures—could factor into who might go into acute respiratory failure, or at least who might suffer from it soonest, and allow for more efficient triaging of patients, with a close eye kept on those with neurological symptoms.

It is important to screen the patients for neurological signs early and late in the course of COVID-19 as this could be life-saving in our fight against COVID-19 pandemic.
Abdul Mannan Baig

Anderson and Perlman add that postmortem examination of the brains of patients who died from COVID-19 are essential to understanding the role nerve damage might play in the progression of the disease. Few, if any, autopsies of these patients are being done because of fear of contracting the disease, and if the autopsies are being done, it’s not likely that examiners are looking at the brain, only the lungs.

They’re just not thinking that the brain could be the site of the problem and so that’s the really important aspect of these reviews, getting that idea out there.
Matthew Anderson



View Full Article



The Scientist