Just saw a news article that a village in the Congo is under quarantine with an new outbreak of ebola.

With out modern air travel & VERY large human population, the world is at an unprecidented risk for a pandemic. If it isn't caused by the bird flu, some other virus will spring up in the next few years.

All we need is a virus from some other species than humans have no natural immunity against to jump the species barrier. Then if it has a sufficiently long incubation period to allow dispersion before symptoms are observed we will have the perfect candidate. If it happens to mutate to allow airborn transmission then watch out!