How do you keep all the virus’ and bacteria from getting out and making people ill?

Question: How do you keep all the virus' and bacteria from getting out and making people ill?
- Keywords:
  experiment,
  how science works,
  research
Asked by to Ian on 19 Mar 2014. This question was also asked by .
- Ian Hands-Portman answered on 19 Mar 2014:
  
  There are a couple of ways – if it’s possible we ask people to bring us dead samples – ‘fixed’ in science speak – that’s the safest way.
  
  If that’s not possible then we use special labs called containment labs – they have special air processing that means that air is constantly sucked into the room and pumped through a steriliser on the way out, we have to work in special boxes and wear two layers of gloves and a special lab coat. To go in we have to use an air lock and once every couple of weeks we fill the rooms with a sterilising gas to kill off anything that might be lurking in the corner.
  
  They’re horrible rooms – I used to work in one every day. The air rushing in makes a lot of noise and we’re not allowed any form of radio or anything in there, it stinks of bleach, plus you can’t scratch your nose. – and noone ever wants to sit next to you at lunch if you’ve been in there.

Question: How do you keep all the virus' and bacteria from getting out and making people ill?