How is the Ebola virus transmitted?

Canada AM: What is hemorrhagic fever? Infectious disease expert Dr. Neil Rau explains what hemorrhagic fever is, how it is transmitted and whether Canadians need to be concerned.

The deaths of at least 59 people in West Africa where health officials are trying to contain a deadly epidemic have renewed concerns about the Ebola virus.

In Canada, lab testing results released on Tuesday confirmed that a Saskatoon man who remains in hospital after a recent trip to Liberia does not have the Ebola virus.

Saskatchewan health officials have not yet confirmed why the Canadian man, who has not been identified, is sick. The province's health officials had said on Monday the man was "seriously ill" with a high fever and other symptoms.

While there are no confirmed cases of Ebola in Canada, the deadly virus is still one that health officials around the world are concerned about. There is no vaccine for the virus, which can cause severe viral haemorrhagic fever (VHF). The deadly fever has a fatality rate of up to 90 per cent, according to the World Health Organization (WHO).

Here’s a closer look at how the virus is transmitted:

Person-to-person

According to the WHO, the first major Ebola fever outbreak occurred in 1976 in Sudan and the Democratic Republic of Congo. More than 400 people died. Ebola is transmitted person-to-person as a result of close-contact with blood, organs, or other bodily fluids of infected people

The WHO says health-care workers treating Ebola patients have "frequently" been infected when not practicing proper infectious control precautions. This includes wearing gloves, mask, or goggles.

Burial ceremonies where mourners have direct contact with the body of a person who died of Ebola can "also play a role in the transmission" of the illness, the WHO says.

Animals-to-humans

Ebola is introduced into the human population through "close" contact with bodily fluids of infect animals, according to the WHO. Infections in Africa have occurred as a result of handling of Ebola-infected chimpanzees, gorillas, fruit bats, monkeys, forest antelopes and porcupines.

In Africa, fruit bats are believed to be possible natural hosts for the Ebola virus.