Virus World

Over a few weeks in November 1889, a respiratory disease attacked half the residents of St. Petersburg, Russia, and it soon began to race through Europe and the rest of the world. Two years later, in a spectacularly detailed book, a British medical officer, H. Franklin Parsons, described what was dubbed the “Russian influenza” epidemic, which raged until 1894. People seemed to spread the disease before developing symptoms, the young did not suffer as much as the old, a dry cough was common among the ill, some had a “perversion of taste and smell,” and deaths rose. Suspicions ran high that a pathogen had jumped from an animal into humans. Sound like COVID-19?

 

In 2005, scientists in Belgium proposed that the earlier pandemic’s cause was not an influenza virus, but rather a coronavirus. Three years before their theory was published, a coronavirus had passed from an animal to humans, touching off a highly lethal outbreak of what was called severe acute respiratory syndrome (SARS). The disease spread from China and brought new attention to these once-obscure viruses. The Belgian team wondered whether something similar happened in Russia more than a century ago. Based on molecular clues, they suggested that the once-deadly virus is still circulating today, as a coronavirus known as OC43 that in most people causes nothing worse than a cold. So far there’s no direct evidence to back the group’s theory, but two other teams soon hope to look at tissue samples from the late 19th century to see whether they can spot when the virus first became a human pathogen.

 

This upcoming search for OC43’s roots is part of a flurry of research, since COVID-19 erupted globally 4 years ago this month, on it and the three other coronaviruses that cause common colds. Long ignored except by a tiny scientific community, these pathogens with clunky, alphanumeric names—NL63, 229E, and HKU1 are the other three—are now getting their due. Some groups are reexamining how the viruses leapt from animals to people, in part to understand how SARS-CoV-2, COVID-19’s cause, may have emerged. Studying the four may also illuminate whether other coronaviruses discovered in wild and domesticated animals pose a threat to humanity. And some scientists are exploring how immune responses to these four overlap and interact with the response to SARS-CoV-2...