Contagion

Dr. Ally Hextall: We've sequenced the virus, determined its origin and we've modeled the way it enters the cells of the lung and the brain. The virus contains both bat and pig sequences. The dark green is pig, and the light green is bat. And here you can see the crossover event. Bat, bat, and pig, bat. And here is a model of the virus and how it attaches to its host. The blue is virus, and the gold is human, and the red is the viral attachment protein and the green is its receptor in the human cells. These receptors are found in the cells of both the respiratory tract and the central nervous system. And the virus attaches to the cell like a key slipping into a lock. Somewhere in the world, the wrong pig met up with the wrong bat.