Professor Steven Hatch, of the University of Massachusetts Medical School, warned there is the potential for the deadly virus to spread at an unprecedented rate.
So far, the latest outbreak, which has mainly affected the Democratic Republic of Congo (DRC) but recently spread to Uganda, has killed at least 1,500 people – making it the second deadliest outbreak of it ever.
But Professor Hatch warned it could get worse.
Writing in the Conversation, he said: “The vaccine keeps the current outbreak partially in check, while instability prevents its eradication.
“By contrast, the West African outbreak of 2014–15 rose with such unprecedented speed that it dominated world headlines for nearly four months between August and October of 2014.
“The alarm it generated led to the international response that helped contain it; today’s DRC outbreak has not resulted in the same alarm.
“The longer Ebola persists in the DRC, the more likely an improbable event will occur – like the spread of the virus beyond the borders of the DRC, or perhaps much further beyond its borders.
“The spread into Uganda may simply be a warning sign.”
Professor Hatch also warned the world should not be “optimistic” that the outbreak will end soon.
He explained: “There is little cause for optimism that the epidemic will end anytime soon.
“What both outbreaks do share is a devastating economic impact, one that can also spread beyond its borders and ‘infect’ the entire region.
“The West African outbreak of 2014–15 cost no less than several billion dollars, possibly as much as tens of billions of dollars.
“If Uganda becomes heavily involved, the current outbreak may prove equally costly.”