Unfortunately there was one hidden side effect of secretly infecting entire families with the condition. As the country grew more and more sick people had been getting to know their neighbors more. For the most part everyone sought to genuinely help their fellow country men but the hidden agenda of many of us was to keep a watchful eye on people with sick members in their families. Half of us were scared of what the sickies might do while the rest of us were genuinely interested in the progression of the disease and wanted to know what to expect for when the effects when it inevitably took hold of our bodies.
When families started disappearing we took it as a sign that the disease had evolved and was now contagious. After four plus years of living in harmony amid the rapid decline and forced isolation of the country America finally began to turn on itself. The government held the key to diffusing the situation but they elected to stay mum on the topic after doing the "extremely difficult" math. Apparently it was better for the little people to be fearful and suspicious of each other and to look to the government for guidance rather than have the little people overthrow the controlling forces and think for themselves.
They killed John and Eve...again. Somewhere in between America being ostracized from the rest of the world and the implosion of the country the government killed the world's first zombie couple. At the time there was mounting concern that the undead might not be killable. Even though folks with the condition were slow moving and generally non violent anything that could not be easily terminated posed a threat. With the number of infected people growing by the day the government wanted to stay one step ahead and elected to see if the zombie people died just like regular people.
As it turned out, they did...kinda. It was determined that people with the condition were most easily killed during the initial stages of the disease directly after they crossed over. During this time the victims were more human than monster and as such were susceptible to anything that might kill a human short of suffocation. As the months passed and the disease progressed the bodies of the undead also evolved. During the later stages their bodies would no longer bleed out and their skin grew tough like beef jerky. As one might assume removal of the head and/or extreme brain damage always resulted in death.
The only unique characteristic in the later stages of the disease was that the liver continued to function and was necessary for survival. Actually, that was how John met his final end. He had proved to be the more docile of the zombie couple and as such had the majority of the experiments performed on him. Researchers were trying to figure out the biology of the disease and how the body was able to survive once it was noted to be clinically dead. They rewarded John with a ration of meat then proceeded to cut him open and do a live autopsy on his body. He happily munched on his food while the doctors removed his organs one by one and cataloged them. When they eventually got to John's liver and severed it from his body, he made a sharp sigh, looked to his left, dropped his meat and died instantly.
