These images are part of a five minute movie representing an infection spreading through a transmission network over time. The data comes from the National Longitudinal Survey of Adolescent Health. The animation uses a new method of network analysis to demonstrate that small differences in reported behavior can potentially explain the large racial disparities in HIV infection observed in the United States.
Circles are women, squares are men. Grey and white coloring are indicative of race. Active partners are indicated with a grey line and people move closer to the person they are partnered with. Concurrency is defined by a person having more than one partnership at a time. The dynamic network simulates the partnerships that happened over a 10 year period in a population of 10,000 young adults, but for this experiment the authors focused on the 600 or so individuals that could eventually become infected. The animation starts with 10 infected individuals chosen at random and quickly builds up a network of ties. When a partnership forms between an infected and an uninfected node, transmission is possible, so this partnership is added to what the authors call the reachable path. These transmitting ties are then kept in the animation to show how the reachable path grows over time. Blue ties mean that when the relationship started both partners were monogamous, while red ties indicate that one or both partners had a concurrent partnership.
The Network Modeling Group also includes Mark S. Handcock, David Hunter, Carter Butts, Steve Goodreau. The animation was produced by Skye Bender-deMoll.