Try to keep a bit of perspective Martin.
They only have about 1,500 cases of it. Mexico city alone is more than 20,000,000 people.
Your co-worker will likely have a great time, and is still more likely to get run over by a bus than get swine flu.
Edit: BBC
http://news.bbc.co.uk/2/hi/talking_point/8018428.stmReaders in the areas affected by the swine flu outbreak have been sending their accounts to the BBC since the first cases were reported.