Scientists from the Canadian Food Inspection Agency and the country's Public Health Agency have demonstrated the virus can be transmitted from pigs to monkeys without any direct contact between them.
Pigs carrying the virus were housed in pens with the monkeys close by but separated by a wire barrier, and after eight days some of the monkeys showed clinical signs typical of Ebola, they said.
The researchers said they believe the monkeys became infected by inhaling large aerosol droplets coming from the pigs' respiratory tracts.
"What we suspect is happening is large droplets -- they can stay in the air, but not long, [and] they don't go far," Gary Kobinger from the National Microbiology Laboratory at the Public Health Agency of Canada told BBC News. "But they can be absorbed in the airway and this is how the infection starts, and this is what we think, because we saw a lot of evidence in the lungs of the non-human primates that the virus got in that way."
More work needs to be done to clarify the role of wild and domestic pigs in possibly spreading the virus to humans, Kobinger said, noting such knowledge could help contain the virus.
"If they do play a role in human outbreaks it would be a very easy point to intervene" he said. "It would be easier to vaccinate pigs against Ebola than humans."