Ebola

Ebola virus disease (EVD) is caused by a virus in the family "Filoviridae". Viruses in this family are very large and have several long filaments or tails. The family Filoviridae has three genera:

• Orthoebolavirus: Ebola virus, Sudan virus, Bundibugyo virus, Taï Forest virus
• Orthomarburgvirus: Marburg virus, Raven virus
• Cuevavirus: Lloviu cuevavirus has not been found in humans

Unlike small viruses, such as the influenza virus, the Ebola virus cannot easily spread through the air and cannot survive for very long on surfaces outside of the body.

The Ebola virus can cause a severe disease called haemorrhagic fever. A haemorrhagic fever is one that involves damage to the blood vessels, loss of white blood cells and platelets, low blood pressure, and shock.

There are other diseases and other haemorrhagic fevers that present the same symptoms as the Ebola disease. Medical tests are required to confirm an Ebola diagnosis.

Ebola viruses have been associated with historical outbreaks in several Central African countries and caused a large outbreak in West Africa from 2014 to 2016. The World Health Organization (WHO) estimates the average case fatality rate is around 50%. Rates have varied from 25% to 90% in past outbreaks.

Ebola virus is spread by direct physical contact with body fluids or tissues of an infected person with Ebola disease or a recently deceased person (for example, blood, saliva, urine, feces, vomit, sweat, semen, breast milk) or from infected animals. The Ebola virus also spreads by contact with contaminated objects such as soiled surfaces (such as clothing or bedding), or medical equipment (such as needles) contaminated with the Ebola virus. There can also be sexual transmission of the Ebola virus, even after a person has recovered from Ebola disease (through semen) and transmission through pregnancy, delivery, and breastfeeding. The virus can enter your body through breaks in your skin (such as a cut), or through your eyes, nose or mouth. 

Ebola is not spread through the air (in other words, it does not spread like the seasonal flu virus), nor is it spread by mosquitoes or water. Walking by an infected person is not enough contact to spread the disease. 

The amount of virus in the body of an infected person becomes significant at the time that symptoms of the illness first appear. The person must be showing symptoms of illness in order to spread the disease. During the incubation period (the time before symptoms become evident), there have been no cases of Ebola disease transmission. 

In Canada, there have been no cases of Ebola disease.  In any area where there is no outbreak, the risk of infection for the general population (people not in direct contact with symptomatic persons) is extremely low. 

Specific occupations (for example, laboratory and health care workers) are at higher risk of exposure, but these workplaces will have infection prevention controls to reduce the risk of exposure. People in an Ebola disease-affected area who protect themselves or have only casual contact are at low risk (for example, health professionals or humanitarian aid workers caring for patients with Ebola disease). Those persons who are at high risk of exposure are those with unprotected, close contact with a potential source of the virus. 
 

Symptoms can begin 2 to 21 days after exposure and usually start with the sudden onset of fever followed by other symptoms. The average time for symptom onset is 6 to 10 days after exposure. Initial symptoms include:

• Sore throat.
• Fever.
• Chills.
• Fatigue.
• Headache.
• Malaise.
• Muscle pain and weakness.

After 4 to 5 days, the illness typically progresses to include additional symptoms such as:

• Rash.
• Nausea, vomiting and diarrhea.
• Eye infections. 
• Hemorrhaging (bleeding from inside and outside the body).

As mentioned above, the risk of exposure outside an area where there is an outbreak is very low. Persons in health care or emergency response who may come in contact with the infected bodily fluids are at some risk. Other situations where exposure may possibly occur outside an affected area include airline crews, servicing and cargo employees, laboratory workers, mortuary and death care workers, and customs or border protection.

The Public Health Agency of Canada has provided guidance on the prevention of Ebola disease. Following personal protective measures whenever there is a possibility of exposure to the Ebola virus is very important in preventing Ebola disease.

The U.S. Occupational Safety and Health Administration (OSHA) lists interim general guidance for workers who are in a known or reasonably suspected environment where they may contact the Ebola virus (for example, there is known contamination by potentially infectious materials). OSHA's recommendations include:

• Follow good infection control practices.
• Meet applicable requirements for personal protective equipment (PPE) and respirators. Care must be taken when putting on and removing PPE. 
• Wear gloves, use good handwashing techniques after removing gloves, and dispose of gloves in properly labelled containers.
• If you might be splashed, sprayed or spattered with body fluids, wear face and eye protection such as a full-face shield or surgical masks with goggles. Aprons or other fluid-resistant clothing must also be worn.
• If you are asked to clean a surface that may be contaminated, your employer is responsible for ensuring you are protected and that appropriate procedures are followed.
• Training about the sources of Ebola exposure and appropriate precautions is provided.

Review the latest travel health advice to practice special precautions before travelling to an area with a known Ebola outbreak. For people who must travel to, or are in an Ebola outbreak area:

• Practice good hygiene.
• Use good hand washing techniques.
• Prevent contact with body fluids (for example, a person showing symptoms, clothes, bedding, needles, medical equipment).
• Avoid contact with animals, including their blood, fluids, or raw meat.

Specific guidance is available from the U.S. Centers for Disease Control and Prevention (CDC) and the National Institute for Occupational Safety and Health (NIOSH) for certain occupations (such as healthcare, airline, emergency response, mortuary, laboratory, etc.).

The Government of Canada states that you must call your appropriate public health authority immediately if:

• You are showing some of the above symptoms.
• You or anyone in your household has recently travelled to an area where there is a confirmed Ebola virus outbreak.

Describe your symptoms and mention your recent travel over the phone before your appointment, so that health care staff can arrange to see you safely without potentially exposing themselves or others to the virus.

Provinces and territories are required to report cases to the Public Health Agency of Canada by:

1. Contacting the Health Portfolio Operations Centre at 1-800-545-7661.
2. Completing an Ebola disease case report form.

Cases should be cared for in highly specialized centres to make sure there is the appropriate supportive care and strict infection controls in place. There is currently no Health Canada approved treatment for Ebola disease.

Two products are approved by the US Food and Drug Administration for the treatment of Ebola virus (species Orthoebolavirus zairense):

1. REGN-EB3 (Inmazeb or atolivimab, maftivimab and odesivimab)
2. mAb114 (Ebanga or ansuvimab)

In Canada, symptoms of Ebola disease are treated as they appear. These basic interventions include:

• Providing fluids intravenously (IV).
• Offering oxygen to maintain blood oxygen levels.
• Using different medications to help with symptoms.

There is currently 1 vaccine approved for Ebola virus disease in Canada (Ervebo, rVSVΔG-ZEBOV-GP vaccine), approved in November 2022. It is only approved for the Ebola virus.

• Ebola disease - from the Government of Canada
• Ebola virus disease - from the World Health Organization (WHO)
• Ebola Disease Basics - from the U.S. Centers for Disease Control and Prevention (CDC)