“This might be a general principle: that a lot of what the virus is doing to us is a consequence of its ability to generate inflammation,” Dr. Datta said.
The new study is based on research carried out at Zuckerman Institute and Irving Medical Center at Columbia University in New York; the New York University Grossman School of Medicine; the Icahn School of Medicine at Mount Sinai in New York; Baylor Genetics in Houston; and the School of Medicine at the University of California, Davis. The research was published online in Cell in early February.
The scientists examined golden hamsters and human tissue specimens from 23 patients who succumbed to Covid. After the hamsters were infected with the original coronavirus, scientists tracked the damage to their olfactory systems over time.
(How do you know a golden hamster has lost its sense of smell? You don’t feed it for several hours and then bury Cocoa Puffs in its bedding, said Benjamin tenOever, a professor of microbiology at NYU Langone Health and an author of the new research. Hamsters that can smell will find the cereal in seconds.)
The virus did not invade neurons, the researchers learned, only the cells that play supporting roles in the olfactory system. But that was enough to alter the function of the nearby neurons, leading to a loss of smell.
The Coronavirus Pandemic: Key Things to Know
A new U.S. strategy. The White House unveiled a virus response strategy that aims for a “new normal,” but much of it will need congressional funding. The plan includes a “test to treat” initiative that would provide antiviral medications to patients as soon as they learn they are infected.
The immune response altered the architecture of genes in the neurons, disrupting production of odor receptors, said Marianna Zazhytska, a postdoctoral fellow at the Zuckerman Institute and one of the paper’s first authors, along with a graduate student, Albana Kodra.
“It is not the virus itself causing all this reorganization — it’s the systemic inflammatory response,” Dr. Zazhytska said. “The nerve cells are not hosting the virus, but they are not doing what they did before.”