Bad news for the immune system: New research has indicated that the likely number of common cold viruses waiting to make a person miserable is perhaps double the long-accepted 100.

Dr. James Gern of the University of Wisconsin School of Medicine and Public Health is leading the UW site for a nationwide study trying to identify rhinoviruses and figure out how to grow them in tissue cultures to study their biology.

Up until now, scientists had identified about 100 cold viruses. But Gern said the new research has found there may be just as many unidentified rhinoviruses out there to make people sick.

“Instead of 100 common cold viruses, there are at least 150 and perhaps as many as 200 cold viruses,” said Gern, professor of medicine and an asthma specialist. “The common cold can cause serious problems for people with asthma and other chronic lung diseases, not just sniffling and sneezing symptoms in otherwise healthy people. This virus can affect the chest as well as the nose in susceptible people, including infants and the elderly.”

For the past 50 years, researchers have studied two classes of viruses responsible for a total of about 100 versions of the cold. Two years ago, after development of molecular techniques to look at the viral genome, researchers found a third class of rhinoviruses. 

“There’s at least one big difference between the classes of rhinoviruses. The first two can be grown in cell cultures, but we haven’t figured out how to grow rhinoviruses in the third class,” said Gern. 

“The goal of the current study is to identify all the new rhinoviruses and find a way to culture them for research.”

Gern said the study could greatly improve the chances of finding a cure for the common cold.

“It looks a lot better than it did two years ago,” said Gern. “When we identify the new group of viruses that has a different biology, it gives us a target. With the discovery of these new viruses, we’re starting to learn how they grow, and now it seems like we could have a good shot at learning now to inhibit them. This research could provide new targets for therapies directed at the common cold, and also cold-induced worsening for chronic lung diseases such as asthma.”

This story is provided by the University of Wisconsin School of Medicine and Public Health.