We drew the Rate Effect card early, which means that whenever you draw a card of the Virulent Strain color during the Infection Phase, you draw another card. This gave us a lot of trouble throughout the game, because we had plenty of Virulent-Strain cards in the deck.
We had seven outbreaks by the end; another outbreak would have meant doom. We also ended up with zero black cubes in reserve at one point; drawing a single black card in the infection phase would have lost the game for us. But we won by the skin of our teeth.
Here's a picture of the board after we won. Experienced Pandemic players will recognize this as a board in great peril, with nine different cities that had three cubes, three of which could outbreak before the next epidemic.