Researchers at Iowa State have developed new technology that can detect just one molecule of the papilloma virus. The current PCR test requires 10-50 molecules for detection. The test allows earlier detection of the virus, and vaccination could still be effective at stopping the virus. The researchers also hope that the same technology can be adapted to detect single molecules of other viruses.
link here: http://www.sciencedaily.com/releases/2007/10/071030164855.htm