Long before you even feel sick, a new Darpa-funded bio-sensor will know what ails you. Researchers at Duke University are developing a device that can betray exposure to a virus even before a person's first sneeze, Wired's DangerRoom blog reports.

The sensor detects changes in gene expression that occur in people exposed to viruses like the common cold, flu, or the respiratory syncytial virus.

Led by Dr. Geoffrey Ginsburg, director of Duke's Institute for Genome Science & Policy, the team identified 30 genetic markers that are activated by viruses. In some cases, the changes occurred hours or days before symptoms started.

This approach would let doctors and public-health officials make quick diagnoses before someone even appears sick. Current tests look for presence of the actual pathogen, but that takes longer and doesn't work until a person has symptoms, Ginsburg says.