Is it even Posssible? The Dead Walking?

This clip from the tv serie "The Walking Dead" is prime example of the type of biotechology that we society, seems to be heading towards. In the main character is cop called Rick Grimes , he in the hospital becuase he got shot. When he wakes up there is no one in the hospital ,the only thing he sees is blood  and dead bodies. Later on he meets two surviver that explians what happend to everyone, he explians that there in zombi apocalypse and all the peoplehe knew where know zombies. So Rick Grimes knows that his family didnt die, so he dicided to go look for them. In the way he faces many danager meets group of 5 people which they are traped in city. So Rick helps them get out of the city and takes them to there family which are in forest near by. When Rick gets to the place in the forest he finds out that his best friend ,wife and his son are there too.So the whole group stike together in order to surivive these  disasters. Later on they dicided to leave the forest and look for help in other place , when they get to city they find huge laboratory. In the laboratory there is only one scientist alive , which ended up helping them out by leting them stay in the laboratory. And than the scientist expalians what happend to the other scientist , that most of them killed them selfs , because they lost hope.And that the only thing that kept him alive was the promise he made his wife to not to give up on trying to find the cure for the disease that turns people in to zombies. Then the scientist explain how disease works , that after the person dies the disesase turns on a part of the person's brain. The scientist later on revelies that when the energy of laboratory is running out , and when that happens the laboratory  will self-destruct. So gruops leave the lab and goes looking for other place where they can be safe. The thing that makes all of these characters be able to survive is that they never lose hope.
          Is even possible to find cure for  such a disease? What even started this disease? If not will that mean that the human race will be extinct? How will humanity start all over again?Will the military be able to stop such thing? If the disease is cured , how long will it take the human population to be the same as it was befor?  Will people lose hope so easily like in the tv serie?  Where would be the best place to hide from the zombies?Should people go to hotter place or colder place in order to escape from the disease? What will be good strategy to survive? Will the seas be good place to live? Will zombies able to swim?