With polio, we've gone several years with no polio in all of Africa, but now with this we're having to go and mop up in that whole region, so it's a bit of a setback for polio. So in parallel we have to go back and get rid of those cases.

You have to be willing to see that sometimes the governments of these poor countries don't come through. You have to think about that as a constraint. How do you help them be better? How do you come up with things that actually work, even in those tough situations.

Often you just have to rely on your intuition.

It's fantastic that Microsoft in the cloud space is one of very few companies that's got the critical mass, the particular emphasis on helping business customers get up to that cloud with all the unique requirements they have. It's very exciting.

There are more people dying of malaria than any specific cancer.

My job is about the most fun thing I do, but I have a broad set of interests, going places, reading things, doing things.

It's the poorer people in tropical zones who will get really hit by climate change - as well as some ecosystems, which nobody wants to see disappear.