Narrator: This is Science Today. Using a genomics-based approach, scientists at the University of California, San Francisco are tracking down viruses that cause human disease. Dr. Don Ganem, a professor of microbiology and immunology and of medicine, has already used DNA microarrays to identify the genome of the newly discovered severe acute respiratory syndrome, or SARS virus. Ganem also discovered that Kaposi's sarcoma is caused by a novel herpesvirus. Now, Ganem is focused on two big categories of human disease.

Ganem: One are other acute diseases that we know are infections but for which we don't know all the causes - so, common colds, respiratory infections, bronchitis, bronchialitis. We know that about 60 or 65 percent of common colds are due to a dozen different viruses, but there's still about a third of common colds whose cause is absolutely unknown.

Narrator: Ganem also wants to determine if viruses may be responsible for certain cancers and autoimmune diseases. For Science Today, I'm Larissa Branin.