Currently, there are no antiviral drugs specifically targeted to noroviruses, but the new knowledge about which segments of the norovirus genome change the least could aid in the development of novel drugs that could be targeted at those more genetically static portions of the virus, say the researchers. Noroviruses, like influenza viruses, mutate readily and evolve rapidly, explains Dr. Green. If vaccines against noroviruses become possible in the future, researchers would need to take into account shifts in the virus's genetic make-up and reformulate the vaccines to match the virus, she adds. However, unlike influenza viruses, noroviruses cannot be grown in the lab, raising an additional hurdle to vaccine development.
"By examining the history of norovirus evolution contained within these archival samples, we can see how the virus has changed during this time, and we also can better predict how the virus is likely to change in the future," says Dr. Bok. If scientists one day crack the problem of growing norovirus in the lab, information about the rate of evolution will be invaluable to developing vaccines, adds Dr. Green.
"This research is the first to reveal the speed at which the molecular clock of norovirus runs," says Dr. Green. Dr. Green and her colleagues are now looking at stool samples from the 1960s in Dr. Kapikian's collection. If norovirus can be detected in those samples, knowledge about the ancestry and rate of evolution of this virus will be further expanded.
|Contact: Anne A. Oplinger|
NIH/National Institute of Allergy and Infectious Diseases