could a zombie apocolypse happen and if so how/why?

Question: could a zombie apocolypse happen and if so how/why?
- Keywords:
  end of the world,
  topical,
  zombie
Asked by to Naomi, Edward, Ian, Mathew, sakshisharda on 17 Jun 2014. This question was also asked by .
- Naomi Osborne answered on 17 Jun 2014:
  
  Good question!
  
  No! Bacteria and viruses won’t keep the dead walking around attacking the living like in World War Z – that’s impossible. There are viruses that can infect our brains so there is a slight chance a virus could arise which affects the way we behave – it’s not impossible for this to happen – but it is extremely unlikely so don’t worry!

Question: could a zombie apocolypse happen and if so how/why?