http://www.nytimes.com/2009/06/03/health/policy/03flu.html?_r=1&hpw

Swine flu may be ramping up. Good for it. There will still be plenty
of hosts even if it reaches strong mortality rates, typically bad (self-limiting)
for pathogens. Fortunately it will
clean scumzones like Africa more than others. HIV is way too slow, although that is of course an advantage in spreading.