Im sure the CDC and WHO have had samples since the original outbreak in the 70's.
It isnt a highly infectious disease, its just highly contagious; it doesnt spread easily and it kills too quickly. Its a bloodborn pathogen, just like AIDS. Fourtunately the carriers die within weeks rather than years so they dont unsuspectingly spread it. The reason why it seems highly infectious is because the victim starts hemorrhaging blood with the onset of symptoms, which increases the likelyhood that those treating the ill will catch it. Basic 1st world country medical protocols will prevent its spread, but in a third world country people arent equipped or educated enough.
It doesnt survive long outside of the host, so it cannot be spread through air or water.
Think zombie movie viruses, they only get passed on through bodily fluid transfer.
