Chelsea Jewell is the main antagonist in the Scott Sigler novel Contagious. At 7 years old Chelsea is the main controller of the secondary infection created by the orbital. Due to her longer Telomeres (which are the DNA equivalent of the plastic tips of a shoe-lace) Chelsea was the ideal host for the secondary infection. It is this secondary infection and Chelsea's ascension leads to the tragic events in Contagious.
The Orbital, a space-born probe and the cause of the infections, makes the logical decision to protect the Triangles and Triangle hosts by creating a caste of protectors. Chelsea Jewell was hit by the Orbital's spores which lead to the secondary infection. With her youth and elongated telomeres Chelsea survived the initial infection to become the main focal point of the infection. Chelsea soon learned from the orbital she too could spread the infection through "smoochies," the triangular spore-producing growths on her tongue. Chelsea spread the disease, first to her own mother and then further creating more and more infected. Soon she found she could further control the "crawlers" (the second stage of the infection) to create a final, devastating weapon which could spell the end of the human race as we know it.
Chelsea is described as being 7 years, 4 months, and 10 days old during Contagious. She was 3 foot, 6 inches tall and described as having bouncy golden curls. This picture of innocence soon became perhaps the greatest threat in the history of man.