Minimum time required to infect entire human population with a virus

I have an idea for a short SF story, where an alien race infects a tiny village with a virus, which eventually spreads to entire Earth. And I need to know what minimum time is required to infect the entire population?

As I remember, there was an assumption in the movie "Outbreak" that initial infection of a small American city with around a hundred initial infected carriers would spread to the entire United States within three days. Assuming the number of commercial flights every day (around 22 thousand per day over Europe only), can we assume that those three days would be enough to spread infection over the entire globe?

The main assumption here is that the virus does not kill immediately (or never). Carriers can successfully infect (many) others while still being alive¹. So, this question seems not to be a duplicate of this one.

Update (after comments): Let's assume, that carrier can infect other person immediately after its own infection and it can survive in dead carrier body, that there is no cure for it and that there is no cure for that. But -- important in my story -- it infects only humans (sort of alien's humanity wipe-out or genocide). If I'm asking about minimum time required to infect entire planet, then take every aspect, that may enlarge this period at minimum and remove all possible obstacles = best infection scenario.

Edit: Would my "problem" and Vincent's model change radically, if we'd assume, that every carrier dies immediately after infecting next carrier?

¹ _{If I remember correctly, there was some work made out there that proved when virus kills carrier within less than 5-6 hours since the initial infection, then such epidemia could never spread into the entire world, because it would not cross continents' borders -- unpiloted planes would fall, uncontrolled ships would sink etc. before reaching new continents.}

posted over 9 years ago

trejder‭

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