Gerry traces the nexus of the viral infection to China, only to find that is one of many mysteries left to unravel with no time to ponder them. Being a medical detective in an apocalyptic war for survival takes a lot of iron nerves for Gerry Lane as he struggles to find the cause for the virus and more importantly the cure. Many times there were missed opportunities to contain the virus before it gets completely out of control. Although American politicians had down played the zombie crisis to prevent wide spread panic, in hindsight it failed miserably.
Many civilians in the occupied territories outside of Israel believe it was a trick by the Israeli Military only to discover too late that it wasn't. The pandemic caused more damage than the survivors realize observations from uninfected witnesses saw many of the ecosystems being either completely damaged or destroyed along with the wildlife that inhabited these environments. The whole picture of how a zombie apocalypse can cause destruction of both the human world and the natural world, including the underpinning of the overall uncertainty of a positive outcome is the main focus of note.
To understand the difference between a single predator and zombies is the factor of intelligence. A predator uses intelligence to catch prey, while zombies spread across a wide area completely mindless consuming everything in their path and leaving nothing behind.