She got on a plane and came to North America where she subsequently felt ill. They are equally as serious and she could still prove to have one of them. The health officials in Canada have stressed that she is getting better and that they are closely watching anyone she came into contact with and that the overall public health risk is very low. But what this situation really brings up is the fact that geographical boundaries are meaningless when it comes to the spread of disease. You cannot contract them by simply being around someone who is ill.
Close contact is needed, which in fact is how outbreaks in Africa occurred.
Part of the funeral process included close contact with the corpse, bathing it and preparing it for burial. This was how the infection was passed around until this practice was stopped. And then specific guidelines include quarantining that person in a negative-pressure room. People attending the patient would have to wear special suits to prevent airborne particles from passing disease. Only in the latest, most serious stages of the disease is this a problem.