Ebola Virus and Viral Hemorrhagic Fevers

Viral hemorrhagic fevers are part of a group of severe febrile illnesses caused by four types of viruses; Arenaviridae, Bunyaviridae, Filoviridae and Flaviviridae.

Ebola virus disease (formerly known as Ebola hemorrhagic fever) is a severe, often fatal illness. Ebola disease is caused by filoviruses (family Filoviridae) that belong to the Orthoebolavirus genus. There are three different viruses are known to cause large Ebola disease outbreaks: Ebola virus, Sudan virus and Bundibugyo virus. EVD has a case fatality rate of up to 90%. It is one of the world’s most virulent diseases.

The virus is transmitted by direct contact with the blood, body fluids and tissues of infected animals or people. Severely ill patients require intensive supportive care. During an outbreak, those at higher risk of infection are health workers, family members and others in close contact with sick people and deceased patients. Orthoebolavirus is spread via droplets that are coughed or sneezed from a sick person and enter the eyes, nose, or mouth of another person who is less than two metres away.

Epidemiology

Summary of epidemiological facts and experience to date: [ref: WHO]

The incubation period of EVD varies from 2 to 21 days. An outbreak of EVD is considered to be over when 42 days (double the 21-day incubation period of the ebolavirus) has elapsed since the last patient in isolation became laboratory negative for EVD.
EVD is transmitted among humans through close and direct physical contact with infected bodily fluids, the most infectious being blood, faeces and vomit. In a household study, secondary transmission took place only if direct physical contact occurred. No transmission was reported without this direct contact.
Orthoebolavirus has also been detected in breast milk, urine and semen. In a convalescent male, the virus can persist in semen for at least 70 days; one study suggests persistence for more than 90 days. Saliva and tears may also carry some risk. However, the studies implicating these additional bodily fluids were extremely limited in sample size and the science is inconclusive. In studies of saliva, the virus was found most frequently in patients at a severe stage of illness. The whole live virus has never been isolated from sweat.
There is no risk of transmission during the incubation period and only low risk of transmission in the early phase of symptomatic patients. The risk of infection during transport of persons can be further reduced through use of infection control precautions.
Orthoebolavirus can also be transmitted indirectly, by contact with previously contaminated surfaces and objects. The risk of transmission from these surfaces is low and can be reduced even further by appropriate cleaning and disinfection procedures.

For more information refer to:

Surveillance

[Ref: PHAC]

EVD has been nationally notifiable in Canada since 2000. As a nationally notifiable disease, ebolavirus cases are reported to the Public Health Agency of Canada through national surveillance systems. The Agency also works closely with its national and international partners, including the World Health Organization, to track EVD outbreaks. Health care workers in Canada should be vigilant for persons with symptoms compatible with EVD and who have returned from affected countries within 21 days of symptom onset.

Case Classification: [Ref: PHAC]

A person with EVD-compatible symptoms is defined as an individual presenting with fever (temperature ≥ 38.0 degrees Celsius) OR at least one of the following symptoms/signs:

subjective fever
malaise
myalgia
headache
arthralgia
fatigue
loss of appetite
conjunctival redness
sore throat
chest pain
abdominal pain
nausea
vomiting
diarrhea that can be bloody
haemorrhage
erythematous maculopapular rash on the trunk

Epidemiological Risk Factors:

Individual who cared for a case of Ebola Virus Disease (EVD).
Laboratory worker handling Orthoebolavirus or processing body fluids from a case of EVD.
Individual who spent time in a healthcare facility where cases of EVD are being treated in a country/region with widespread and intense Ebola virus transmission.
Sexual contact with an EVD case.
Close contact in households, healthcare facilities, or community settings with a person with Ebola while the person was symptomatic – close contact is defined as being for a prolonged period of time within approximately 2 meters (6 feet) of a person with Ebola.
Contact with any human remains of a case of EVD or contact with human remains in a country/region with widespread and intense Ebola virus transmission.
Contact with bats, primates or wild animal bush meat from affected countries/regions.
A travel history to a country/region with widespread and intense Orthoebolavirus transmission within 21 days constitutes a low risk factor.

Person Under investigation (PUI)

A person with EVD-compatible symptoms (as defined above) AND EVD has not been ruled out.

A travel history to a country/region with widespread and intense EVD transmission within 21 days of symptom onset OR exposure to one of the epidemiological risk factors within 21 days of symptom onset.
With or without pending laboratory results for EVD.

Confirmed Case

A person with laboratory confirmation of EVD infection using at least one of the methods below:

Isolation and identification of virus from an appropriate clinical specimen (e.g., blood, serum, tissue, urine specimens or throat secretions) (performed at the National Microbiology Laboratory) OR
Detection of virus-specific RNA by reverse-transcriptase PCR from an appropriate clinical specimen (e.g., blood, serum, tissue) using two independent targets or two independent samples AND confirmed by the National Microbiology Laboratory by nucleic acid testing or serology OR
Demonstration of virus antigen in tissue (e.g., skin, liver or spleen) by immunohistochemical or immunofluorescent techniques AND another test (e.g., PCR) OR
Demonstration of specific IgM AND IgG antibody by EIA, immunofluorescent assay or Western Blot by the National Microbiology Laboratory or an approved WHO collaboration centre OR
Demonstration of a fourfold rise in IgG titre by EIA, immunofluorescent assay from an acute vs. a convalescent serum sample (performed at the National Microbiology Laboratory).

For more information on EVD surveillance:

National Case Definition: Ebola virus disease (EVD) (PHAC)
EVD Case Report Form (PHAC)
Ebola and Marburg Virus Outbreak Toolkit (WHO)

Signs and Symptoms

EVD is a severe acute viral illness often characterized by the sudden onset of fever, intense weakness, muscle pain, headache and sore throat. This is followed by vomiting, diarrhea, rash, impaired kidney and liver function. Bleeding from gums, nose, injection sites and gastrointestinal tract occurs in about 50% of patients. Dehydration and significant wasting occur as the disease progresses. Laboratory findings include low white blood cell and platelet counts and elevated liver enzymes.

People are infectious as long as their blood and secretions contain the virus. The incubation period is 2 to 21 days. Other diseases that should be ruled out before a diagnosis of EVD can be made include: malaria, typhoid fever, shigellosis, cholera, leptospirosis, plague, rickettsiosis, relapsing fever, meningitis, hepatitis and other viral haemorrhagic fevers.

There is no effective antiviral treatment for ebolavirus infections. Treatment is supportive, and is directed at maintaining renal function and electrolyte balance, and at combatting haemorrhage and shock.

Ebola Disease: Symptoms and Treatment (PHAC)

Vaccines

In Canada, the Ebola Zaire vaccine, Ervebo^® (EZV) is recommended for individuals 18 years of age or older for protection against EVD. This vaccine is not indicated for use against the other orthoebolaviruses, such as Sudan virus or Bundibugyo virus, or related filoviruses, such as Marburg virus

- Ebola Virus Vaccine: Canadian Immunization Guide (PHAC)
- Ebola Virus Vaccines (WHO)

Infection Prevention and Control

For health care providers in Canada: [Ref: PHAC]

Orthoebolaviruses are transmitted by direct contact (e.g., through broken skin or mucous membranes) with the blood or other body fluids (e.g., stool, urine, saliva, semen) of an infected individual and/or indirectly through contact with environmental surfaces and fomites contaminated with body fluids. Orthoebolavirus are not transmitted through Airborne transmission.
The incubation period of EVD varies from 2 to 21 days. Cases are not considered to be communicable before the onset of symptoms but communicability increases with each subsequent stage of illness and the case remains communicable as long as blood and body fluids secretions contain the virus. This includes the post-mortem period.
Use Contact and Droplet Precautions, in addition to Routine Practices, in settings where contact with patients suspected or confirmed to have EVD is anticipated. The need for enhanced PPE (e.g., double gloving, leg and shoe coverings, hair/head covering) is determined by assessing the risk of heavy exposure to blood and body fluids.
The effectiveness of PPE (gowns, gloves, masks, facial protection, respirators) is highly dependent on appropriate selection and proper use, including correct technique and sequence for putting on and taking off PPE, discarding into designated receptacles, and hand hygiene to minimize risk of transmission
PPE should be provided in a clean area outside the patient’s room or in the anteroom.
Consider assignment of trained individual to monitor appropriate selection and application, removal and disposal of PPE, to observe and ensure HCW not contaminating self and to monitor entry to room (i.e., limit entry to only essential HCWs).
The need for enhanced PPE (e.g. double gloving, leg and shoe coverings, hair/head covering), is determined by assessing the risk of heavy exposure to blood and body fluids). Note: In late stages of EVD, there may be copious secretions and excretions.

PERSONAL PROTECTIVE EQUIPMENT (PPE) INSTRUCTIONAL VIDEOS

PPE CHECKLISTS

Summary of Recommended IPAC Practices for Hospitalized Patients with EVD (Ref: PHAC)

Accommodation:

Single patient room with dedicated toilet/commode, door closed.
Maintain a log of all persons entering room; only essential personnel to enter.
Patients who also have symptoms compatible with airborne infections (i.e., measles, tuberculosis) should be placed in an airborne infection isolation room (AIIR) as soon as possible.
Although Orthoebolavirus is not transmitted by the airborne route, it may be practical for facilities with airborne infection isolation rooms (AIIR) to isolate suspected EVD patients in an AIIR as this will allow an appropriate space (anteroom) for putting on and taking off personal protective equipment (PPE), ensure the presence of a dedicated washroom, and allow aerosol-generating medical procedures (AGMPs) to be performed, if required.
Consider assignment of trained individual to monitor appropriate selection, application, removal and disposal of PPE, to avoid contamination of the HCW, and to monitor entry to room (i.e., limit entry to only essential HCWs).

Hand Hygiene:

Hand hygiene is according to the Four/Five Moments for Hand Hygiene (provincial recommendations should apply). Use alcohol-based hand rub, or soap and water if hands are visibly soiled.

Precautions

Perform a point-of-care risk assessment before every interaction with the patient.
Use Routine Practices for all care
Use Droplet and Contact Precautions for all care.
PPE should be removed and disposed of in the anteroom and hand hygiene performed before touching the face. If an anteroom is not available, PPE should be removed at the doorway before exiting the room. PPE should be discarded in the patient room.

Equipment

Only take essential equipment into the patient room.
Use disposable equipment whenever possible, or dedicate equipment to the patient.
Limit the use of needles/sharps as much as possible.
Clean equipment according to routine hospital practices.
There are no indications for the use of disposable dishes/cutlery, except in the circumstance of non-functioning dishwashing equipment.

Linen

Place soiled linen in clearly-labelled, leak-proof bags at the point-of-use. Handle with minimum agitation to avoid contamination of air, surfaces and persons.
Transport linen directly to the laundry area and handle according to routine protocols.
Perform hand hygiene after handling soiled linen.

Environmental Cleaning

Provide education and appropriate PPE to those responsible for environmental cleaning.
Assign responsibility and accountability for cleaning and disinfection of patient care environment; consider auditing to ensure appropriate processes.
Use approved hospital-grade disinfectants for cleaning the environment.
Surfaces that are likely to be touched and/or used frequently should be cleaned and disinfected on a more frequent schedule. This includes surfaces that are in close proximity to the patient (e.g., bedrails, bedside/over-bed tables, call bells) and frequently touched surfaces in the patient care environment, such as door knobs, surfaces in the patient’s bathroom.
Additional cleaning measures or frequency may be warranted in situations where environmental soiling has occurred.
When precautions are discontinued or the patient is moved, terminal cleaning of the room/bed space and bathroom, changing of privacy curtains and cleaning and disinfection or changing of string/cloth call bells or light cords should be done.
Biomedical waste (e.g., items soaked with blood or secretions) should be contained in impervious waste-holding bags or double bags according to municipal/regional regulations.
Blood, suctioned fluids, excretions and secretions should be disposed of in a sanitary sewer or septic system according to municipal/regional regulations.

Visitors:

Only essential visitors should enter the patient’s room.

Laboratory Information and Specimen Collection

[Ref: PHAC]

Samples from patients are an extreme biohazard risk. Testing for Ebola virus should be conducted under maximum biological containment conditions.

The Public Health Agency’s National Microbiology Laboratory (NML) is the only facility in Canada that can work with live haemorrhagic fever viruses such as Ebola virus. The NML offers the world’s highest level of containment and meets or exceeds all national and international guidelines for safety and security.

Health professionals should not undertake any laboratory testing on a patient suspected of having EVD or any other viral haemorrhagic fever infection.

If a sample requires testing, immediately contact the Agency’s 24-hour emergency line: 1-800-545-7661. An expert will assist you in developing an Emergency Response Assistance Plan for the safe shipping of the sample to the Agency’s NML.

Biosafety Guidelines for Laboratories Handling Specimens from Patients Under Investigation for Ebola Virus Disease (PHAC)

Travel Advice

It is recommended that Canadians should practice special health precautions, such as receiving additional vaccinations. A notice at this level would be issued if there is an outbreak in a limited geographic location, a newly identified disease in the region or a change in the existing pattern of disease.

The risk of a tourist or businessman/woman becoming infected with Ebola virus during a visit to the affected areas and developing disease after returning is extremely low, even if the visit included travel to the local areas from which primary cases have been reported. Transmission requires direct contact with blood, secretions, organs or other body fluids of infected living or dead persons or animals, all unlikely exposures for the average traveller. Tourists are in any event advised to avoid all such contacts. [Ref: WHO]

Travel Health Notices (PHAC)

Ebola, Marburg and Viral Hemorrhagic Fever Resources

Public Health Agency of Canada (PHAC)

World Health Organization (WHO)

Centers for Disease Control (CDC)

Provincial Ebola and Viral Hemorrhagic Fever Resources

Alberta

BC Centre for Disease Control

Public Health Ontario

Other Links