Canada is stepping up precautions and will start implementing screenings at airports in six cities, including Halifax Stanfield International, to try and prevent Ebola from entering the country.

Federal Health Minister Rona Ambrose made the announcement Wednesday.

A statement, from the new head of the Public Health Agency of Canada, noted there are no direct flights to Canada from the affected countries in West Africa.

Dr. Gregory Taylor of the Public Health Agency of Canada says quarantine officers will have the necessary training and equipment to undertake a health assessment of travellers at airports. (Public Health Agency of Canada)

Dr. Gregory Taylor said under the Quarantine Act, travellers to Canada who are unwell are supposed to declare that fact when they arrive in this country. Likewise they should declare if they've been in contact with a sick person. Anyone who is ill or reports having had contact with a sick person is referred to a quarantine officer.

Quarantine officers will be stationed at six airports across the country: Montreal, Toronto, Vancouver, Halifax, Ottawa and Calgary.

"Quarantine officers have the necessary training and equipment, including temperature monitoring devices, to conduct a health assessment and determine whether additional health measures are required," he said in the statement.

"Should these travellers identify themselves in this manner, a temperature check will now be administered."

As well, Taylor said the Public Health Agency will be increasing the number of staff at Canadian airports to help with the screening of travellers from Ebola-affected regions.

In an emailed response to a request for information, the Public Health Agency said border agency officers at crossings that do not have a quarantine officer present can connect via technology with one around the clock.

Ambrose's announcement came the same day authorities in the United States said that country would start to use enhanced airport screening for incoming passengers at the five airports that handle most flights from the affected West African countries.

Incubation period complicates screening efforts

Likewise, some people who are infected with some diseases — Ebola is one of them — may not be aware they are infected when they answer the border agent's questions. The incubation period for Ebola can be as long as 21 days after exposure to the virus, during which time the person would appear and feel well. With Ebola, it is believed people are only contagious when they have symptoms.

Thomas Earl Duncan, the Liberian man who died Wednesday, did not have symptoms when he arrived in Dallas on Sept. 20. He started to feel ill four days later. So airport screening that involved asking "Are you ill?" or requiring incoming passengers to agree to have their temperature taken would not have identified him as a risk.

As far as the current Ebola outbreak goes, the risk that Canada might get an imported case is not zero, but it is low, experts suggest.

Dr. Kamran Khan, who studies the spread of infectious diseases by analyzing international air travel patterns, said Canada gets few travellers from Guinea, Liberia and Sierra Leone, the three most badly affected countries in this outbreak. Only 1.5 per cent of travellers from those countries come to Canada, he said.

The months-long Ebola outbreak is the worst in known history. On Wednesday the World Health Organization said at least 8,033 people have been infected so far and nearly 3,900 of them have died.