This lifespan of varroa has been posted on several forums and bee info.
Having questioned pertinent answers , The following  was said : Varroa live
for 5 months. Varroa can live for 5 days without the host.Varroa die when
subject to freezing temperatures. And there was more , but I don't remember
because it is of no value. My own observations Are : Varroa died within 3
hours in a gass jar. Varroa died in 24 hours in a glass jar. I am still not
further ahead.  Varroa can walk relatively fast. Varroa are introduced by
drones is my definite observation, stray workers are also the culprits.
Picking swarms is a sure bet for mite pick up, unless you do NOT combine and
treat them in a quarantine environment, If you can.It is very doubtful that
people transport mites on them unless it is on purpose.
The spread of varroa is determined by the lifespan  when it involved long
distances such as the americas versus NZ or Australia. One could say that
varroa travels with bees which travel undetected in cargo or in nooks and
crannies of ships and aircraft.If the information of the lifespan of 5 days
without a host is correct than the mite cannot survive over a longer
duration of travel. That leaves the introduction to aircraft provided it is
on bee which sits in nooks and crannies. That raised the question how cold
it is in cargo holds of aircraft and how long it takes to kill bee and mite
under thses conditions. There is a heck of a lot we do not know . May
somebody comes  up with another plausible answer.
catfish