Public Health Management of Cases and Contacts of Ebola Virus Disease in the Community Setting in Canada
Updated: August 1, 2018
The strategy outlined in this guidance is rapid case and contact management (i.e., to reduce opportunities for transmission to contacts and ensure timely assessment of contacts). The objective of this guidance document is containment.
This guidance document updates the previous Public Health Management of Cases and Contacts of Human Illness Associated with Ebola Virus Disease (EVD) (June 22, 2015). This updated guidance document aligns with recommendations for returning travellers and provides revised definitions for exposure risk that are consistent with other guidance documents. All forms/tools associated with this document have also been updated.
This guidance document is based on currently available scientific evidence, expert opinion and guidance provided by other countries and agencies, e.g., World Health Organization (WHO), European Centre for Disease Prevention and Control (ECDC), United Kingdom (UK) and United States Centers for Disease Control and Prevention (CDC). This guidance document is subject to change as new information becomes available. It should be read in conjunction with relevant federal, provincial, territorial (FPT) and local legislation, regulations and policies, and adapted to local context as required. This document has been developed based on the Canadian situation and therefore may differ from guidance developed by other countries.
Target audience and scope
The Public Health Measures Expert Task Group (PHM ETG) has developed this updated guidance with Public Health Agency of Canada (PHAC) Program Experts to support FPT and local public health authorities in the event that a case or contact of EVD is identified within their jurisdiction. The PHM ETG consists of selected individuals who are recognized public health experts within Canada in the field of community based disease control strategies. Its purpose is to provide a forum for expert public health measures discussions related to the prevention, control and mitigation of the spread of infectious diseases, including emerging infectious diseases, in the community.
Using a risk assessment approach, this guidance provides advice for managing symptomatic and asymptomatic contacts in the community. Clinical judgement remains essential and this, along with jurisdictional policies, may result in decisions that differ from recommendations provided in this document. Guidance pertaining to laboratory, specimen testing, clinical care, infection prevention and control (IPC) measures in other settings (e.g., Canadian points of entry, healthcare settings, pre-hospital care settings, passenger conveyances, and airline cabins) are addressed in other guidance documents.
Beyond the scope of this document are requirements for health care workers with occupational exposure in Canada, who would be managed as per employer policy, and with consultation with public health authorities as required. Refer to the Infection Prevention and Control guidelines.
Additional information regarding Ebola Virus Disease (EVD) is available on Canada.ca. The following key points form the basis for the recommendations:
- Person-to-person transmission can occur:
- through direct physical contact with blood and/or other body fluids (e.g., feces, urine, emesis, saliva, sweat, breast milk, semen) from an infected symptomatic person or dead body AND / OR
- indirectly through physical contact with surfaces and fomites (e.g., needles) that are contaminated with these fluids.
- With the exception of the potential for sexual transmission of Ebola virus (EBOV) during the convalescent period, EBOV cannot be spread to others by an asymptomatic person.
- EBOV is not transmitted between humans through airborne transmission or casual interactions.
- Infected persons are not considered to be communicable before the onset of symptoms.
- The risk of transmission is highest when viral load is greatest, such as when a person is acutely unwell.
- Cases remain communicable as long as blood and body fluids contain the virusFootnote 1, including in the post-mortem period; the body of an EVD case is highly infectiousFootnote 2,Footnote 3.
- During recovery, EBOV can also persist for weeks to months in some body fluids (e.g., semen, urine, and breast milk)Footnote 1,Footnote 4 -Footnote 8.
Clinical presentation and course of illness:
- EVD has an incubation period of between 2 and 21 days, with most cases experiencing onset of symptoms around 4 to 10 days after exposure.
- Symptoms usually begin with a sudden onset of flu-like symptoms, such as fever, myalgia, severe headache and malaise, typically followed by worsening gastrointestinal symptoms (e.g. anorexia, nausea and abdominal discomfort), vomiting and diarrhea.
- Non-fatal cases have fever for several days and typically begin improving around day six to elevenFootnote 9.
- Diarrhea and vomiting are often profuse in later stages of the illness and, without treatment, lead to severe volume depletion, electrolyte abnormalities, wasting and shock.
- In fewer than half of cases, hemorrhage may occur as a late manifestation, usually from the gastrointestinal tract or other mucosa (e.g. gums, nose).
- Secondary bacterial infections are also common.
- Full recovery occurs over a long period of time, and is often associated with long term sequelae such as myelitis, recurrent hepatitis, psychosis, or uveitisFootnote 1.
- Untreated, case fatality in humans can range from 25-90%.
- There is currently no licensed treatment for EVD.
- A number of investigational therapeutics, namely antivirals and monoclonal antibodies, are currently under development.
- Cases should receive care in highly specialized centers, in order to ensure appropriate supportive care (maintaining blood pressure, electrolyte balance and organ systems function) under strict infection prevention control management.
- There is currently no licensed vaccine against EBOV in Canada.
- An unlicensed vaccine (rVSV-ZEBOV-GP, Merck) for the Zaire ebolavirus species has completed early stage investigational trials, and has been available on compassionate grounds in recent outbreaks (West Africa 2014-16, DRC 2018).
- The vaccine may also be offered to front-line humanitarian workers deploying to EVD-affected areas, as an outbreak management measure.
- The vaccine is not licensed or marketed in Canada, and is only currently available in Canada through limited clinical trials.
Risk in Canada
- Although the risk of exposure to EBOV in Canada is considered to be very low, it is conceivable that the introduction of a case connected to an outbreak in an EVD-affected area could occur.Footnote 10
- If this were to occur, public health authorities at all levels would be involved in the response, that would be led by provincial/territorial public health authorities.
- PHAC is working closely with its national and international partners to track and to monitor EVD activity around the world, and is assessing the risks of EVD in Canada on an ongoing basis. Information on current outbreaks can be found on the World Health Organization (WHO) website.
Public Health Management of: Persons Under Investigation, Confirmed Cases and Convalescent Persons
National case definitions for EVD have been established for use during Ebola outbreaks. Canadian public health authorities monitor and respond, as necessary, to all EVD outbreaks and adjust recommended practices in Canada as required. The role of public health in EVD detection and management is multifaceted and includes: the early identification of cases and contacts through surveillance; contact tracing; educating public and health care professionals; and communication. Public health authorities also support continuity of case and contact management within Canada.
Persons under Investigation
In Canada, the national case definition for a Person Under Investigation (PUI) is a person who has symptoms of EVD AND an epidemiologic risk factor. If public health is notified of a person meeting the PUI case definition (e.g., a contact under monitoring develops symptoms), public health would direct the individual to take immediate measures to prevent transmission to others (detailed in the “Recommendations for contacts who have developed EVD compatible symptoms” section of this document) and arrange, as per PT protocol, for the individual to undergo a medical assessment at an appropriate acute care facility to confirm or to rule out EVD.
If medical assessment and laboratory investigations cannot initially rule out EVD, the PUI must continue to be under public health follow up for the duration of the 21-days (after last possible exposure), OR, until EVD can be ruled out.
Confirmed cases of EVD in Canada will be hospitalized in specialized EVD treatment centres with the capacity to provide appropriate treatment and effective isolation. It is recommended that public health authorities liaise daily with appointed hospital staff for the duration of the patient's hospitalization, to monitor progress and to be actively involved with discharge planning.
The decision to discharge (PDF) should be made jointly, in consultation with infectious disease and public health consultants. Discharge is determined on a case-by-case basis, and considerations include that the patient is physically well enough to leave the hospital and their infectious risk is minimal. Guiding discharge decisions are:
- the patient has been symptom free for greater than 72 hours
- two consecutive blood samples at least 24 hours apart have been negative for the Ebola virus by PCR
Upon discharge, the convalescent case must receive education and counselling to address the associated disease sequelae AND prevent transmission to others during their convalescence.
Counseling of the convalescent case should include the following:
- instructions regarding any medical follow-up that may be required;
- information regarding possible sexual transmission of EVD including:
For male convalescent cases, recommend that:
- the individual either abstain from sexual contact or observe safe sex practices through correct and consistent condom use and follow recommendations for testing of semen;
- semen be tested at three months after onset of disease and then, for those who test positive, every month thereafter until two consecutive negative semen tests, at least one week apart have been documented. Please refer to PHAC guidance on Ebola Specimen Testing for relevant specimen testing information.
If semen testing is not done, recommend that abstention or safe sex practices be continued for at least 12 months after onset of symptoms. This interval may be adjusted as additional information becomes available on the prevalence of Ebola virus in the semen of survivors over time. Additional information is available regarding sexual transmission of the Ebola Virus Disease.
For female convalescent cases, recommend that:
- breastfeeding be discontinued until breast milk is confirmed negative for Ebola virus.
Public Health Management of Contacts
For the purposes of this document, a contact is a person who has been or may have been exposed to the Ebola virus in the past 21 days. Exposure can occur through direct physical contact with the blood or other body fluids of an infected: symptomatic person, dead body or animal; or indirectly from an Ebola virus contaminated surface or fomite.
The purpose of contact tracing is to:
- ensure contacts are aware of their potential exposure, any symptom monitoring expectations, risk mitigation measures and what to do if they develop EVD symptoms;
- identify any symptomatic contacts as early as possible;
- facilitate prompt laboratory diagnostic testing and treatment, and
- reduce the risk of transmission to others.
In Canada, local PH authorities are responsible for initiating contact tracing. Once a PUI is identified, PH authorities would assess the need to commence contact tracing using the epidemiological and clinical information provided.
In determining the need to initiate contact tracing, the following factors would be taken into consideration:
Communicable period and communicability:
- infectiousness starts from the time of symptom onset (i.e., only symptomatic individuals can transmit the virus);
- the risk of transmission from a case is low(er)Footnote i in the early stages of disease, when the viral load is lower, and increases over time, when a case becomes more infectious as the viral load increases, and the cases develops later stage symptoms such as: diarrhea, vomiting or bleeding;
- the incubation period is 2 - 21 days after an exposure, and determines the length of time contact monitoring is required;
- the nature of the exposure: whether the risk of exposure is considered as high or low (based on individual risk assessment).
Risk Assessment of Contacts
All individuals who are contacts of a confirmed case should be rapidly identified and assessed by public health authorities, to determine their risk of exposure and the appropriate public health recommendations.
To facilitate determining the public health recommendations, contacts are classified according to their risk of exposure. Note: exposure may occur before or after a symptomatic person is determined to be a confirmed case.
A high-risk of exposure includes any of the following:
- Direct physical contact, without adhering to recommended infection, prevention and control (IPC) precautions or due to a breach in IPC precautions, with:
- the body surface/mucous membranes of a symptomatic EVD case, their body fluids, their dead body, or
- any other known source of Ebola virus (e.g., including contaminated medical instruments, objects or environmental surfaces).
- Unprotected sexual contact with an acute or convalescent EVD case (see section Convalescent Cases - key counseling points, above).
A low-risk of exposure includes any of the following:
- Physical contact , while adhering to recommended IPC precautions and no known breach in IPC precautions, with:
- the body surface/mucous membranes of a symptomatic EVD case their body fluids, their dead body, or
- any other known source of Ebola virus (e.g., including contaminated medical instruments or environmental surfaces),
- Having only casual interactions AND no direct (unprotected body surface to body surface) physical contact with an EVD case or their body fluids. Examples of casual interactions include sharing a seating area on public traveller transportation or sitting in the same waiting room.
Public health authorities assessing the risk of exposure in travellers returning from an EVD affected area should apply the criteria above, with the exception of requiring contact with a “confirmed case” since the status of the EVD case many not be known by the traveller. Note that these recommendations are consistent with the Committee to Advise on Tropical Medicine and Travel ( CATMAT) statement “Ebola Virus Disease: Canadian Recommendations for Preventive Measures, Monitoring, and Surveillance of Travellers” , however the CATMAT statement refers to international case definitions which include confirmed, probable or suspect case definition.
The goal of contact management is to monitor an individual at risk of developing EVD symptoms and to minimize the risk of transmission to others. The public health guidelines for contact management in the Canadian community setting are detailed below and a supporting algorithm tool is located in at the end of this document.
It is acknowledged that public health authorities may need to enhance or tailor the recommendations to best manage various situations, such as non-compliance and potential risk to public. In addition, in rare circumstances, the public health authority may choose to implement full quarantine measures or to issue an order under relevant provincial/territorial public health legislation to compel a person to comply with instructions.
Recommendations for all asymptomatic EVD contacts
During the 21-day period following the last potential exposure to the Ebola virus, it is recommended that all contacts, regardless of their risk of exposure, do ALL of the following:
- receive active public health monitoring for symptoms check and counselling;
- self-monitor for symptoms of EVD, including checking and documenting oral temperature twice daily (am and pm), and immediately if they start feeling chills/feverish (Temperature Recording Form for Contacts of Ebola Virus (PDF));
- report to the appropriate public health authority as directed;
- be prepared to immediately self-isolate (i.e., physically separate and ensure a 2 metre distance from other people exists) and to contact relevant public health authority should EVD-compatible symptoms develop,
- advise all healthcare providers that they encounter, including paramedic services, of their potential EVD exposure
- try to avoid medications that are known to lower fever (e.g., acetaminophen, ibuprofen, acetylsalicylic acid) as these medications could mask an early symptom of EVD; if these must be taken, they should advise their public health authority;
- postpone elective medical visits and other elective procedures (e.g., elective dental visits, elective blood tests);
- refrain from donating blood, sperm and any other body fluid or tissue;
- maintain good respiratory and hand hygiene practices, and
- report any travel intentions outside of the public health jurisdiction, to the public health authority.
Additional recommendations for asymptomatic contacts with a high-risk of exposure
During the 21-day period following the last potential exposure to the Ebola virus, in addition to the recommendations for all EVD contacts (above), it is recommended that contacts with a high-risk of exposure:
- remain near an acute care facility (e.g., within one hour's drive, if possible, to facilitate rapid transfer to the facility) where medical care with appropriate IPC measures can be implemented;
- either abstain from sexual contact or observe safe sex practices through correct and consistent condom use for the duration of the 21-day period (and refer to recommendations for convalescent cases if this contact becomes an EVD case);
- not attend public places (e.g., grocery store, shopping mall, medical clinic, school, funeral, religious congregation);
- not travel on public/commercial conveyances (e.g., bus, train, taxi, airplane); and
- further limit contact with others (e.g., in the work-place) if appropriate based on the individual's risk assessment. Full quarantine may be recommended if there are concerns around public safety.
Recommendations for symptomatic contacts
If a contact develops EVD-compatible symptoms, public health authorities would:
- Advise the individual to:
- immediately self-isolate (maintain a 2 metre distance and no physical contact with people or pets/animals) if not already isolated from others;
- wash hands, especially after vomiting or toileting,
- ensure that others do not come into contact with their blood or body fluids (including urine, feces, emesis, saliva, sweat, and semen) or anything that may have come in contact with their blood or body fluid (e.g. linens, clothing, toilet, toiletries). Refer to Measures for the Management of Ebola Virus Disease-associated Waste in Home or Alternate Settings for management of EVD-associated waste.
Arrange, per PT protocol, for the individual to have a medical assessment at an acute care facility, to confirm or to rule out EVD. It is recommended that the individual not take public conveyances (bus, train, taxi) to that facility. Depending on the nature/severity of symptoms and proximity to the facility, the individual may be able to take a private vehicle to the hospital and avoid direct contact with others or may need to take an ambulance to the hospital.Footnote iii It is important to ensure that the Paramedic Services (if involved) and the receiving acute care facility are informed of the EVD-compatible symptoms in advance to help to ensure that appropriate IPC measures are in place during transport and before their arrival at the acute care facility.
Public health recommendations for specific groups and community settings
Community-based EVD control strategies should be considered in the context of the current epidemiology of the disease and the evidence on effective public health measures. The likelihood of EVD transmission from person to person in the community is dependent on the nature and timing of the exposure (direct exposure to a symptomatic, infected person or their body fluids).
Given the abundance of precaution being exercised for all potential contacts of EVD as described earlier, the risk to others through casual interactions is considered to be very low. Therefore, it is considered unlikely that EVD transmission will occur in a public setting such as in schools, at a shopping mall, grocery store, funeral or religious congregation in Canada. Public health authorities should continually assess the potential risk for EVD transmission within the community and communicate relevant disease prevention advice as necessary.
Algorithm: Public Health Management of Contacts of Ebola Virus Disease in the Community Setting in Canada
The algorithm is a summary of the process for the public health management of contacts of Ebola Virus Disease (EVD) in the community setting in Canada, as recommended in this document. It begins with the identification of contacts. A contact is a person who has been or may have been exposed to the Ebola virus in the past 21 days. Exposure can occur through direct physical contact with the blood and/or other body fluids of an infected: symptomatic person, dead body or animal; or indirectly from an Ebola virus contaminated surface or fomite.
Additional Tools and Templates
To support public health follow up of contacts, the following tools and templates can be found appended to this document:
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