Doctors in Dallas, Texas, missed a chance to contain the Ebola virus when it arrived in North America.

Thomas Eric Duncan arrived at a hospital on Friday complaining of symptoms. Even though he said he had recently been in West Africa, doctors sent him home with medication.

Health authorities are now monitoring some 80 people for signs of the disease. They include up to 18 people who had contact with Duncan after he began displaying symptoms, and those who have been in proximity to the first group. None are showing signs of illness.

The concern that Ebola might spread is raising questions about whether Canada is prepared to handle an outbreak. Government and Health officials say the risk to Canadians is very remote, but they making preparations in the event cases begin to appear here.