One may believe zombies are pure science-fiction, but it is scientifically possible. Many believe that If a plague could induce zombie-like symptoms, then it would have arisen by now. However AIDS started as a simian disease that was harmless to humans, but eventually it had mutated and was able to infect humans and thousands of lives have been claimed by HIV.
Another thought is that there simply couldn't be a disease that would turn humans into zombies. However rabies can turn a loyal pet into a frothing beast. The olfactory nerve, the one that allows you to smell, has direct access to areas in the brain that control recognition, hunger, and inhibiting actions. I believe the government should create a plan to combat a disease that could cause zombie-like symptoms.