what to do in such a situation?

some of my colleagues were talking about something which i overheard. then i realised they were talking about a colleague which has athelete's foot. the worst encounter was when we went ktv. being enclosed in a small room, the smell was just unbearable but we had to bear with it for 4 hrs! today i had to endure for 1.5 hrs during a training in the conference room when she was sitting beside me. something must be done, someone needs to tell her about this. we thot of a few ideas.

1. giving her a foot spray on her birthday but it's still a few months down the road.

2. then someone suggested exchanging gift on one of my colleague's farewell but we thot it's so ridiculous as it's not christmas.

3. i wanted to send her an email discreetly but someone said it's better to tell her in the face. i just couldnt bring up the subject when i see her considering we aren't that close.

4. we'll pretend to go to a shoe shop and talk about which kind of shoes will cause odor hoping she gets the hint but what if she doesnt?