Ebola disease prevention, monitoring and surveillance recommendations

An Advisory Committee Statement (ACS)
Committee to Advise on Tropical Medicine and Travel (CATMAT)

Last partial content update: February 2024

Last complete chapter revision: March 2023

On this page

• Preamble
• Key points/messages
• Objective
• Introduction
• Methods
• Epidemiology
• Likelihood of exposure during travel
• Preventive measures for travellers
• Recommendations for monitoring and surveillance of travellers arriving from Ebola Disease-affected areas based on exposure risk
• Treatment of Ebola Disease
• Acknowledgements
• Conflict of interest
• References

Preamble

The Committee to Advise on Tropical Medicine and Travel (CATMAT) provides the Public Health Agency of Canada (PHAC) with ongoing and timely medical, scientific, and public health advice relating to tropical infectious disease and health risks associated with international travel. PHAC acknowledges that the advice and recommendations set out in this statement are based upon the best current available scientific knowledge and medical practices, and is disseminating this document for information purposes to both travellers and the medical community caring for travellers.

Persons administering or using drugs, vaccines, or other products should also be aware of the contents of the product monograph(s) or other similarly approved standards or instructions for use. Recommendations for use and other information set out herein may differ from that set out in the product monograph(s) or other similarly approved standards or instructions for use by the licensed manufacturer(s). Manufacturers have sought approval and provided evidence as to the safety and efficacy of their products only when used in accordance with the product monographs or other similarly approved standards or instructions for use.

Key points/messages

• Transmission of orthoebolaviruses occurs primarily via direct contact with infected blood, body fluids, or tissues of a symptomatic person, a deceased case, or an infected animal, or with surfaces contaminated with the body fluids of infected persons.
• No cases of transmission from casual interaction with asymptomatic returning travellers from affected areas have been reported.
• CATMAT suggests that, while most of the currently available scientific evidence comes from experience with Ebola virus (EBOV), approaches recommended for prevention and management of EBOV also apply to other species, such as Sudan virus (SUDV), Bundibugyo virus (BDBD), and Taï Forest virus (TAFV).
• This guidance document reflects the revised taxonomy of family Filoviridae, as approved by the International Committee on Taxonomy of Viruses (ICTV) in April 2023 and is subject to change as new information becomes available.

Objective

This statement developed by CATMAT is intended to provide recommendations for preventive measures, monitoring and surveillance of travellers returning from EBOD-affected areas and healthcare and other humanitarian workers with potential contact with EBOD patients.

Introduction

EBOD is a severe, potentially fatal illness caused by RNA viruses of the genus Orthoebolavirus^{Footnote 1}. There are four species of orthoebolavirus known to cause human disease: Ebola virus (Orthoebolavirus zairense, EBOV), Sudan virus (Orthoebolavirus sudanense, SUDV), Bundibugyo virus (Orthoebolavirus bundibugyoense, BDBD), and Tai Forest virus (Orthoebolavirus taiense, TAFD). Speciation is important because treatments and vaccines developed against one species may not have similar effectiveness against others. EBOV, causing Ebola virus disease (EVD), and SUDV, causing Sudan virus disease (SVD), are most commonly implicated in recent outbreaks^{Footnote 2Footnote 3}.

Orthoebolaviruses are most frequently^{Footnote 4} transmitted to humans through contact with the infected blood, body fluids, and/or tissues of a person with symptomatic disease or a deceased case^{Footnote 5Footnote 6}. They can also be transmitted through:

• contact with infected animal reservoirs
• physical contact with surfaces and fomites (for example, needles, medical equipment, clothes, bedding) contaminated with infected fluids
• vertical transmission (during pregnancy or delivery)
• sexual transmission during the acute phase or, particularly for male cases, during the convalescent period^{Footnote 7Footnote 8Footnote 9Footnote 10Footnote 11Footnote 12}

Orthoebolaviruses are not transmitted between humans through airborne transmission^{Footnote 12Footnote 13}.

The previous experiences of early sustained transmission of EBOD in urban settings (2014-2016) in Africa highlighted the importance of rapid response for outbreak management including timely mobilization of resources for the prevention of spread of EBOD through active management of clinical cases (isolation and treatment) and contacts (tracing, quarantine, vaccination and monitoring)^{Footnote 14Footnote 15}. Timely response also includes^{Footnote 16Footnote 17Footnote 18}:

• enhanced monitoring and case detection at transport hubs
• entrance and exit screening at international airports
• enhancement of local laboratory capacity
• strategic vaccination of contacts and healthcare workers
• treatment of clinical cases in dedicated Ebola treatment units (ETUs)
• community engagement, public awareness and education, including promotion of safe and dignified burial practices

Methods

This statement was developed by a CATMAT working group of volunteers, none of whom declared a relevant conflict of interest. Criteria outlined in the CATMAT statement on Evidence Based Process for developing travel and tropical medicine related guidelines and recommendations were used to decide whether a Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodological approach would be appropriate for this chapter. The GRADE approach was not used as this statement is in response to an outbreak for which urgent travel-related guidance is required. Advice is based on a narrative review of the relevant literature and on expert opinion, and consideration of applicable WHO guidance. The final statement and recommendations were approved by CATMAT.

Epidemiology

Sustained chains of transmission of the viruses causing EBOD are typically restricted to areas of sub-Saharan Africa, with foci of epidemic disease occurring in parts of Central Africa, West Africa and East Africa^{Footnote 19}. The most recent SVD outbreak in Uganda ending on January 11, 2023 included cases from 7 regions: Jinja, Kampala, Kassanda, Kyegegwa, Masaka, Mubende, and Wakiso^{Footnote 20}.

Outbreaks of EBOD have most recently^{Footnote 2} been reported from:

• Uganda (September 20, 2022 to January 11, 2023)
• The Democratic Republic of the Congo (DRC), in the Provinces of:
  • North Kivu (three outbreaks declared between February 7, 2021 and September 27, 2022)^{Footnote 21Footnote 22Footnote 23}
  • Équateur (two outbreaks declared between June 1, 2020 and July 4, 2022)^{Footnote 24Footnote 25}
• Guinea, in the Nzérékoré Region (February 14, 2021 to June 19, 2021)^{Footnote 26}

To date, fifteen outbreaks have been recorded in the DRC since the first recognized outbreak in 1976^{Footnote 2}. The tenth outbreak in the Provinces of North Kivu, Ituri and South Kivu (August 1, 2018 to June 25, 2020) was the country's longest EVD outbreak and the second largest in the world after the 2014–2016 EVD outbreak in West Africa^{Footnote 27}.

In addition, during the large-scale 2014-16 outbreak affecting Sierra Leone, Liberia, and Guinea^{Footnote 28}, exportation of cases elsewhere in Africa and to Europe and North America occurred with limited secondary transmissions^{Footnote 29Footnote 30}. Given the prolonged incubation period of EBOD (that is, up to 21 days) and relative ease of international travel, EBOD manifesting once an exposed and infected traveller returns home is not unexpected^{Footnote 31}. Further, recovered EBOD patients sometimes have prolonged carriage of infectious EBOV in immune sanctuary sites (such as, testes, eyes), with reports of EBOV transmission through sexual activities or other close contact months to years after an epidemic has been declared over^{Footnote 10}.

Nevertheless, experience indicates that the risk of EBOD transmission outside of an outbreak area, by an individual traveller who returns home without symptoms, is very low. In the 2014-2016 outbreak affecting West Africa, no cases of EVD were imported to Canada and very few cases were exported outside of the affected countries^{Footnote 28}.

More recent outbreaks have had significantly altered epidemiology due to the availability of EVD vaccines for healthcare workers and close contacts of EVD-infected patients. During the 2014-2016 rVSVΔG-ZEBOV-GP Ebola vaccine (Ervebo^®) trials, immediate vaccination of close contacts had a 100% effectiveness at preventing EVD and is therefore expected to improve outbreak response in the future^{Footnote 32}.

Transmission

Transmission of EBOD occurs via handling, preparing or ingesting infected animals (for example, bats, wild game), or via contact with the blood, body fluids (for example, stool, vomitus, saliva, semen), or tissue of infected human cases during their symptomatic illness or soon after death, directly or via objects contaminated with such fluids^{Footnote 5Footnote 6Footnote 7Footnote 9Footnote 11}.

Those at particular risk for acquisition of EBOD include healthcare workers^{Footnote 33} and family members tending to ill relatives, as well as those involved with the burial process, including preparing the deceased for burial^{Footnote 6}.

EVD and SVD have an incubation period of between 2 and 21 days, with most cases manifesting clinical disease within 6 to 10 days following exposure^{Footnote 34}. Risk of transmission is highest when viral load is greatest in infected individuals, such as patients who are acutely unwell with fever, vomiting, and diarrhea, or soon after their death^{Footnote 35}. Current evidence suggests that transmission does not occur prior to the onset of symptoms in the acute phase of the illness^{Footnote 5}.

Following recovery and release from isolation, the risk of sexual transmission can remain a concern for EBOD survivors^{Footnote 9Footnote 11}, due to asymptomatic persistence of orthoebolaviruses in semen^{Footnote 36}. For example, viable Ebola virus (Orthoebolavirus zairense) has been shown to persist for several months and perhaps less commonly, for years in body organs that are protected from the survivor's immune system, such as the testes, eyes and central nervous system (CNS)^{Footnote 10}.

Transmission of EBOD from mother-to-child has been well documented, and nearly all cases of congenital EVD transmission during the 2014-2016 EVD outbreak in Sierra Leone, Liberia and Guinea resulted in the death of the fetus^{Footnote 8Footnote 37}. Pregnant women with EBOD may also experience severe clinical outcomes, including death, more frequently than non-pregnant adults^{Footnote 38}.

Specific guidance from the WHO is available on the prevention of congenital and post-partum transmission of EBOD to infants. While comprehensive review of the topic is outside the scope of this document, specific recommendations include the discontinuation of breastfeeding for mothers with acute EBOD and immunization of exposed mothers^{Footnote 39}.

Clinical manifestations

EBOD is characterized by an abrupt onset viral syndrome consisting of fever, malaise, myalgia, pharyngitis, severe headache, and conjunctival injection^{Footnote 5}. Gastrointestinal symptoms frequently appear a few days later, with vomiting and large-volume diarrhea that can be bloody. These symptoms may be accompanied by a maculopapular or petechial rash that can progress to purpura^{Footnote 40}. Given the non-specific nature of early disease (viral prodrome), a high index of suspicion based on epidemiology is required.

In up to half of patients, some bleeding may occur from mucosa (gums, nose), from the gastrointestinal or urogenital tract, or at venipuncture sites^{Footnote 41}. As the disease progresses, dehydration leading to electrolyte abnormalities may become severe, followed by wasting and listlessness.

Severe EBOD cases with hemorrhagic symptoms usually have concurrent and significant multi-system and end-organ damage such as acute kidney injury, central nervous system (CNS) dysfunction, bone marrow suppression (with leukopenia and thrombocytopenia), and liver failure^{Footnote 40Footnote 42}. The course of the disease can be further complicated by secondary bacterial infections. Historically, EBOD outbreaks have always occurred in malaria-endemic countries, indicating malaria co-infection occurs and warrants screening^{Footnote 43Footnote 44}.

The average EBOD case-fatality rate is high even with optimal intensive care, and if death occurs, it is usually 7 to 10 days after symptom onset^{Footnote 5Footnote 42}. Survivors have a prolonged recovery phase, and can experience a range of complications after recovery. Sequelae include: non-specific fatigue, joint pain, muscle aches, uveitis, etc^{Footnote 45}.

Monitoring of recovered cases is warranted since recurrence/relapse of EBOD can occur, although rare, and the latency period is not well established^{Footnote 46}. Follow-up testing can also be necessary to determine at what moment the body fluids (breast milk, semen) are no longer infectious^{Footnote 47Footnote 48}. Duration and frequency of follow-up testing for viral shedding after acute EBOD is not well established.

Likelihood of exposure during travel

The likelihood of exposure and infection with an orthoebolavirus is generally very low for travellers. The routes for potential exposure are the same as for residents living in areas of risk, with certain groups, for example, healthcare workers providing direct care to patients, being at substantially increased likelihood for exposure, especially if delivering care in an area suffering an outbreak.

Recent reports of prolonged carriage of EBOV in semen leading to infections in women, months to years after the male's acute infection, raises the possibility of travellers sexually acquiring the virus from an EBOD-recovered male^{Footnote 36Footnote 49}. While not precisely known, this risk is likely considerably smaller than the risk of acquiring other sexually transmissible infections and likely mitigated through similar means such as the consistent use of barrier methods, like condoms. In addition, vaccination may be considered for sexual partners of recovered EBOD patients in Canada in consultation with provincial or territorial public health authorities.

Travellers to EBOD-affected areas are advised to monitor the local news media and adhere to all airport procedures, including entry and exit screening, as directed by local authorities.

Preventive measures for travellers

General travel advice applicable to all travellers to areas where EBOD is considered a hazard

• Travellers are advised to practice frequent hand hygiene while abroad, either with soap and water, or with an alcohol-based hand rub. This helps prevent common viral and bacterial infections, such as influenza, norovirus and traveller's diarrhea, but also potentially severe infections like EBOD.
• Travellers are advised to avoid close contact with live or dead animals, avoid handling raw or undercooked meat and avoid consuming wild game.
• Condoms should be used during sexual activity with any new partners while abroad, for the prevention of common sexually transmissible infections, as well as EBOD.

Travellers to EBOD-affected areas

Guidance on preventive measures for healthcare workers who are providing care to patients with suspected or confirmed EBOD is available elsewhere^{Footnote 33Footnote 50}, and is not otherwise addressed in this section. Humanitarian aid workers should follow guidance provided by their organization in addition to the guidance provided in this document.

People travelling to an EBOD-affected area for the purpose of visiting friends and relatives should exercise a degree of caution beyond that of typical tourist travellers, given that they often stay in local homes for a more prolonged period of time, and may be consuming wild game, which can present a risk for EBOD transmission^{Footnote 40}. In addition to the general preventive measures listed above, such travellers should:

• be cautious of exposure to ill friends and relatives in a household setting
• be aware of and adhere to safe burial practices^{Footnote 51}

Extensive recommendations for provision of care to a family member in EBOD-affected areas are available from the WHO^{Footnote 52}. However, in an EBOD-affected area, fever and/or severe clinical illness in a local household where the traveller may be exposed, should be brought to the attention of local health authorities whose recommendations should be followed. In such a scenario, transfer to a healthcare facility for evaluation and care should occur promptly.

Travellers in or planning a visit to an affected area should be made aware that they could become subject to local requirements, for example if they come into contact with a known or suspected case. Further, if they were to acquire symptomatic disease, there is no assurance of medical evacuation to a Western health care centre, or of access to all supportive interventions and others that might be available for disease management in Canada.

Vaccines against EBOV

rVSVΔG-ZEBOV-GP Ebola vaccine (Ervebo^®, Merck)

A recently developed Ebola virus vaccine (Orthoebolavirus zairense), Ervebo^®, has been used to vaccinate humanitarian workers and contacts in an outbreak of EVD in the DRC (EBOV outbreak) with excellent results^{Footnote 53}. Effectiveness of immediate vaccination of close contacts against EVD occurring 10 days after vaccination approaches 100%^{Footnote 32}.

As an outbreak management measure, the vaccine may be offered to some humanitarian workers deploying to an EVD-affected area (such as, to those that may provide care to confirmed EVD cases or their contacts, including contacts of a deceased case), or to those that may be engaged in safe burials, and to other healthcare or frontline workers in affected areas and areas at high risk of spread^{Footnote 53}. Furthermore, strategies for "ring vaccination" and other vaccination strategies have been very effective in curtailing EVD outbreaks and are summarized elsewhere^{Footnote 54}. However, while Ervebo^® is now authorized in Canada, it is not currently available or recommended for Canadians as part of routine immunizations or vaccinations prior to travel^{Footnote 55}.

Within Canada, a stockpile of vaccine may be available via Canada's National Emergency Strategic Stockpile (NESS) for the management of exposures to cases detected in Canada and management of potential outbreaks. Access to the vaccine and information on who is eligible to receive Ervebo^® for management of exposures or outbreaks within Canada would be determined in consultation with the relevant public health authorities. Humanitarian organizations working in EVD-affected regions may have secured supplies of this Ebola virus vaccine directly through the manufacturer or supplier or through the global vaccine stockpile available through the World Health Organization^{Footnote 56}. The provision of vaccination against EVD to Canadians travelling for international aid work remains the responsibility of the organization delivering services. Individuals travelling to EVD-affected areas through humanitarian organizations should enquire with their host organization about the availability of Ebola virus vaccination.

Vaccinated individuals must undergo the same monitoring and surveillance measures as those who have not been vaccinated when returning from affected areas. At this time, Ervebo^® vaccine is not approved or recommended to prevent other strains of orthoebolaviruses, including Sudan virus, Taï Forest virus and Bundibugyo virus. Due to significant antigenic differences, Ervebo^® vaccine is not expected to provide significant protection against other strains of orthoebolaviruses, including SUDV (the cause of the 2022-2023 Uganda outbreak).

For more information on the Ervebo^® vaccine, refer to the Interim Statement on the Use of the rVSVΔG-ZEBOV-GP Vaccine for the Prevention of Ebola Virus Disease.

Ad26.ZEBOV (Zabdeno^®, Janssen) and MVA-BN-Filo (Mvabea^®, Bavarian Nordic)

This new prime-boost Ebola vaccine has received a marketing authorization from the European Medical Authority (EMA) in 2020. Zabdeno^® is given first and targets EBOV, while Mvabea^® is a multivalent vaccine against EBOV, SUDV, TAFV and Marburg virus, and is administered approximately eight weeks later as a booster. This prophylactic 2-dose regimen is therefore not suitable for an outbreak response where immediate protection is necessary, as it requires 2 doses and 8 weeks to become immune^{Footnote 5Footnote 57}. Five clinical studies conducted in Europe, Africa and the USA demonstrated that this vaccine regimen is safe and could induce an immune response against Ebola virus. Efficacy data in humans has been extrapolated from animal studies. The exact level of protection provided by the vaccine regimen is however unknown. This product is not licensed for use in Canada.

Returning travellers

The risk of exportation and further transmission of EBOD outside affected areas may theoretically be mitigated through the implementation of exit screening measures. Such measures are usually put into place to identify symptomatic persons and/or those who may have had a high risk of exposure to an EBOD case. They can be implemented within an affected country (for example, between areas of active transmission and areas where no transmission has been documented) as well as at international points of entry/exit (for example, air and water ports, land border crossings, etc.).^{Footnote 18}

Some entry and exit screening measures, such as temperature checks, may be implemented in some countries^{Footnote 58}, however pre-symptomatic or sub-clinical cases will generally not be identified, and fever is a non-specific sign that can be seen in numerous non-EBOD travel-related illnesses.^{Footnote 59}

As part of usual practice, Canada Border Services Agency personnel screen for ill passengers as per the Quarantine Act with subsequent referral of symptomatic travellers to a Quarantine Officer for a health assessment. As per the Quarantine Act, when arriving in Canada, all travellers who are feeling unwell, must disclose to a Canadian Border Services Agent if they have been or suspect to have been in close proximity with someone who has a communicable disease^{Footnote 60}.

Definitions of exposure risk to travellers

A traveller is considered to have no known exposure of concern if:

• they are not a household contact, a sexual contact or have not had any known direct contact with a symptomatic EBOD case or their body fluids, their dead body or materials or surfaces contaminated with their body or body fluids within the previous 21 days
• they are only a contact of a contact, for example, even if they have interacted with an asymptomatic person who has been providing care or living in the same household as an EBOD case
• they have resided in a region with known or suspected transmission, but have no known contact with a symptomatic case
• symptomatic or not, they have not travelled to an affected sub-national region where cases have been reported in the past 21 days even if they have travelled to a country reporting EBOD cases
• any possible exposure occurred over 21 days prior to arrival in Canada

Any of the following are considered as a low risk of exposure:

• direct contact with the following, while adhering to recommended Infection prevention and control (IPC) measures for Ebola disease in acute care settings and no known breach in IPC precautions:
  • a symptomatic EBOD case, their body fluids, their corpse, or any other known source of orthoebolaviruses (for example, an infected animal or positive laboratory specimen)
  • objects or surfaces that may be contaminated with orthoebolaviruses from the body fluids of a patient, including bedding, clothing, and/or medical instruments
• had only casual interactions, and no direct contact, with an EBOD case or their body fluids (examples of casual interactions include sharing a seating area on public transportation or sitting in the same waiting room)
• stayed in a community where there is active transmission of Ebola disease, but does not meet any of the criteria for a high-risk exposure

Any of the following are considered as a high risk of exposure^{Footnote 6Footnote 45}:

• direct contact with the following without adhering to recommended IPC precautions, or due to a breach in IPC precautions:
  • a symptomatic EBOD case, their body fluids, their corpse, or any other known source of orthoebolaviruses (for example, an infected animal or positive laboratory specimen)
  • objects or surfaces that may be contaminated with orthoebolaviruses from the body fluids of a patient, including bedding, clothing, and/or medical instruments
• any household or sexual contact with a case
• unprotected sexual contact with a person recovering from EBOD, since the virus can persist for months in the semen of infected males^{Footnote 47}
  • while possible, female to male transmission through vaginal secretions of recovered females has not been described^{Footnote 45}

Healthcare and humanitarian aid workers are considered differently in terms of assessment of their exposure risk from other travellers due to the nature of their potential risk of exposure. Some healthcare and humanitarian workers may elect to have a 21-day pre-travel quarantine to decrease their risk of travelling while ill, however, if they arrive in Canada within 21 days of working in an affected area, healthcare and humanitarian aid workers should:

• self-identify to the appropriate public health authority following their arrival, even if they have no known exposures or only a low risk of exposure
• self-identify immediately to a Canadian Border Services Agent or Quarantine Officer at the airport, if they have a high risk of exposure or have EBOD-compatible symptoms

It should be noted that travellers who are symptomatic or who have a high risk of exposure are unlikely to present at a point of entry into Canada as EBOD-affected areas usually implement exit screening. However, in the early stages of an outbreak, there is a possibility that travellers could exit an EBOD-affected area via public conveyance, either due to inadequate exit screening or due to the unknown/unrecognized nature of an exposure.

Recommendations for monitoring and surveillance of travellers arriving from EBOD-affected areas based on exposure risk

Specific recommendations for monitoring and surveillance of returning travellers are established by the Quarantine Act and by provincial and territorial public health authorities. The recommendations herein are intended as guidance for health officials and individuals and not intended to replace specific requirements set by the Quarantine Act or provincial or territorial public health authorities. These recommendations apply only to individuals returning from EBOD-affected areas, defined as specific sub-national regions where cases are documented. Travellers returning from countries where EBOD cases have been reported, but without travel to the affected area(s) of the country (whether symptomatic or not), should be evaluated as returning travellers with no exposure to EBOD.

1. Travellers from an EBOD-affected area with no known exposure of concern

• We suggest that returning travellers with no symptoms should be encouraged to check the Public Health Agency of Canada's website for information on EBOD^{Footnote 61} and what to do if they develop symptoms in the 21 days following their departure from the affected area.
• It is recommended that these travellers follow the Category 1 recommendations regarding monitoring and surveillance provided in Table 1.

Physicians seeing travellers with symptoms and with no known exposure should contact their appropriate public health authority for further guidance.

2. Travellers from an EBOD-affected area with low risk of exposure and without symptoms

Upon arrival in Canada, it is recommended that these travellers:

• self-identify to the appropriate public health authority during the first business day following arrival in Canada for counselling regarding processes and procedures in the event that EBOD-compatible symptoms develop over the potential incubation period
• follow the Category 2 recommendations regarding monitoring and surveillance provided in Table 1 for the remaining balance of the 21-day period following the last potential exposure to EBOD

3. Travellers from an EBOD-affected area with high risk of exposure and without symptoms

In the event that a traveller learns of their high risk of exposure while in transit to Canada, it is recommended that these travellers:

• self-identify to a Canadian Border Services Agent who will contact a Quarantine Officer who will perform an individual risk assessment and determine what actions will be required to support the traveller and protect those around them
• follow the Category 3 recommendations regarding monitoring and surveillance provided in Table 1 for the remaining balance of the 21-day period following the last potential exposure to EBOD

In the event that a traveller learns of their high risk of exposure, after entering Canada, it is recommended that these travellers:

• self-identify to the appropriate public health authority who will perform an individual risk assessment and determine what actions will be required to support the traveller and protect those around them.
• follow the Category 3 recommendations regarding monitoring and surveillance provided in Table 1 for the remaining balance of the 21-day period following the last potential exposure to EBOD

Humanitarian aid workers should follow the guidance provided by their organization in addition to the guidance provided in this document.

4. Travellers from an EBOD-affected area who have developed EBOD-compatible symptoms

If a traveller from an EBOD-affected area is found to have EBOD-compatible symptoms upon arrival at a point of entry in Canada, the traveller should:

• self-identify to a Canadian Border Services Agent who will contact a Quarantine Officer. As per the Quarantine Act the Quarantine Officer will immediately conduct a health assessment and make any necessary arrangements (including issuing any necessary orders) for medical and/or appropriate public health authority follow-up^{Footnote 60}
• follow the Category 4 recommendations regarding monitoring and surveillance provided in Table 1 for the remaining balance of the 21-day period following the last potential exposure to EBOD

If a traveller from an EBOD-affected area develops EBOD-compatible symptoms after entering Canada, during the 21-day period following the last potential exposure to EBOD, the traveller should:

• immediately self-isolate (stay home until they seek health care and maintain a 2-metre distance and no physical contact with people or pets/animals)
• wash hands, especially after bleeding, 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 (for example, linens, clothing, toilet, toiletries). Refer to Measures for the management of Ebola virus disease-associated waste and linen in Home settings for management of EBOD-associated waste
• if seen by a health care practitioner, be triaged for screening and assessment in accordance with Infection prevention and control measures for Ebola disease in acute care settings
• follow instructions provided by the appropriate public health authority

If the traveller's symptoms require immediate medical intervention, the appropriate public health authority should be notified to ensure that all paramedic, emergency medical services and health care providers the patient may interact with are prepared to take appropriate IPC precautions. The public health authority will aid with:

• arranging for the individual to have a medical assessment at an acute care facility (where appropriate IPC measures can be implemented, if located in close proximity to the individual), to confirm or rule out EVD, SVD or other EBOD
• recommending appropriate transport to hospital. Usually this is via ambulance unless the public health authority permits travel to the medical facility by private vehicle. Individuals under investigation for EBOD should not take public conveyances (that is, do not take a bus, train, taxi, rideshare) to the hospital or healthcare facility
• ensuring the paramedic or emergency medical services (if involved) and the receiving acute care facility are informed of the status of the traveller with EBOD-compatible symptoms in advance to help ensure that appropriate IPC measures are in place during transport and before their arrival at the acute care facility

Table 1: Monitoring and surveillance of travellers arriving from Ebola Disease (EBOD) affected areas^{Footnote 1}

Risk categories	Category 1: Travellers with no known exposureFootnote 2 without symptoms	Category 2: Travellers with low risk of exposureFootnote 3 without symptoms	Category 3: Travellers with high risk of exposureFootnote 4 without symptoms	Category 4: Travellers with EBOD compatible symptomsFootnote 5
Proposed actions
Action upon arrival in Canada	Travellers should check the Public Health Agency of Canada's website for information on EBOD and what to do if they develop symptoms in the 21 days following their return to Canada.	Travellers should self-identify to appropriate public health authority the first business day following their arrival in Canada for counselling regarding processes and procedures in the event that EBOD-compatible symptoms develop over the potential incubation period.	Travellers should self-identify to a Canadian Border Services Agent who will contact a Quarantine Officer. The Quarantine Officer will conduct an immediate risk assessment and determine what actions will be required.	Travellers should self-identify to a Canadian Border Services Agent who will contact a Quarantine Officer. Quarantine Officer will conduct an immediate health assessment and make any necessary arrangements for medical and/or public health follow-up.
Operational guidance (for the balance of the 21-day period since the last possible exposure)
Onward domestic travel permitted?	Yes	Yes	To be determined by Quarantine Officer or Medical Officer assessment.	No
Monitoring	No	Travellers should immediately start self-monitoring for symptoms of EBODFootnote 7	Public health authority determines plan for monitoring for symptoms of EBODFootnote 7	Yes (in hospital and then according to exposure risk if EBOD is ruled out at time of assessment)
Contingency planning	Not applicable	Travellers should: prepare to immediately self -isolate and contact the relevant appropriate public health authority should EBOD-compatible symptoms developFootnote 8 report any travel intentions to public health authority to acquire contact information for the destination's public health authority	Travellers should: prepare to immediately self-isolate and contact the appropriate public health authority should EBOD-compatible symptoms developFootnote 8 develop a plan to readily access healthcare if it becomes necessary, including remaining near appropriate acute care facility (within one hour's drive, if possible)Footnote 9 report any travel intentions to the public health authority to acquire contact information for the destination's public health authority	Not applicable
Attendance at WorkFootnote 6	Yes	Yes (following assessment by the public health authority)Footnote 10	No	No (until EBOD ruled out)
Going out in public placesFootnote 6	Yes	Yes (following assessment by the public health authority)Footnote 10	No	No (until EBOD ruled out)
Use of public conveyancesFootnote 6	Yes	Yes (following assessment by the public health authority)Footnote 10	No	No (until EBOD ruled out)
Other precautions	Not applicable	Travellers should: try to avoid medications that are known to lower feverFootnote 11, if these must be taken, advise public health authority advise all healthcare providers that they encounter, including paramedic services, of their potential exposure to EBOD postpone elective medical visits and other elective procedures (for example, elective dental visits, elective blood tests) not donate blood or any other body fluid or tissues maintain good respiratory and hand hygiene practicesFootnote 12	Travellers should: try to avoid medications that are known to lower a feverFootnote 11, if these must be taken, advise public health authority advise all healthcare providers that they encounter, including paramedic services, of their potential exposure to EBOD postpone elective medical visits and other elective procedures (for example, elective dental visits, elective blood tests) not donate blood or any other body fluid or tissues abstain from sexual contact or observe safe sex practices for 21 days further limit contact with others (for example, quarantine) if appropriate based on the individual's risk assessment as per public health authority assessment maintain good respiratory and hand hygiene practicesFootnote 12 Humanitarian aid workers should: follow guidance provided by their organization in addition to the guidance provided in this document	Not applicable
Footnote 1 Ebola Disease (EBOD) affected areas include specific sub-national regions where active cases are reported and recognized as outbreak areas. Travelling to an affected country without travel to affected subnational regions should generally not require monitoring or surveillance. Return to footnote 1 referrer Footnote 2 Have not had direct contact with a symptomatic EBOD case or their body fluids; or may have interacted with an asymptomatic person who has been providing care or living in the same household as an EBOD case. Return to footnote 2 referrer Footnote 3 Direct contact with a symptomatic EBOD case, their body fluids, their corpse, or any other known source of orthoebolavirus while adhering to recommended Infection Prevention and Control (ICP) precautions and no known breach in ICP precautions; or living in the same household but did not have direct contact with a symptomatic case or their body fluids (for example, through contaminated surfaces); or having only casual interactions and no direct contact with an EBOD case or their body fluids. Examples of casual interactions include sharing a seating area on public transportation or sitting in the same waiting room. Return to footnote 3 referrer Footnote 4 Direct contact with a symptomatic EBOD case, their body fluids, their corpse, or any other known source of orthoebolavirus without adhering to recommended ICP precautions; or due to a breach in ICP precautions; or unprotected sexual contact with an acute or convalescent EBOD case. Return to footnote 4 referrer Footnote 5 Ebola disease symptoms at point of entry. Return to footnote 5 referrer Footnote 6 Assessments could be made by the public health authority on a case-by-case basis. For example, a jog or a bike ride in a non-urban setting could be considered. Attending a community or religious gathering should be avoided. Staying at home with family could be considered; visiting family elsewhere should not be permitted. The operating principle is that the appropriate public health authority must be able to satisfy itself, and the general public, that the objectives of isolation are being achieved on a sustained basis throughout the 21-day period. Return to footnote 6 referrer Footnote 7 Monitoring includes checking and documenting oral temperature twice daily. Refer to the Temperature Recording Form for Contacts of Ebola Disease (PDF). Return to footnote 7 referrer Footnote 8 Self-isolating includes maintaining a 2-meter distance and no physical contact with others. Return to footnote 8 referrer Footnote 9 The public health authority will indicate whether an appropriate acute care facility has been identified in the area for this purpose, where appropriate infection prevention and control measures can be implemented. Return to footnote 9 referrer Footnote 10 In general, essential activities can be maintained (for example, work, grocery shopping), but unnecessary direct contact beyond household members should be avoided. Return to footnote 10 referrer Footnote 11 Medications that are known to lower fever (for example, acetaminophen, ibuprofen, acetylsalicylic acid) should be avoided as these medications could mask an early symptom of EBOD; if these must be taken, advise public health authority. Return to footnote 11 referrer Footnote 12 Refer to hand washing and staying healthy for more information. Return to footnote 12 referrer

Treatment of EBOD

The treatment of EBOD remains aggressive supportive care, often in the intensive care setting with availability of appropriate personal protective equipment and isolation facilities. In addition, two monoclonal antibody treatments have been shown to be effective in reducing mortality in EBOV-infected patients with lower viral loads during the 2018 North Kivu outbreak^{Footnote 5}. Atoltivimab, maftivimab, and odesivimab (REGN-EB3, sold as Inmazeb), and ansuvimab (mAb114, sold as Ebanga) are monoclonal antibody treatments which have been shown to be moderately effective at reducing mortality in EVD patients with lower serum viral loads (defined as a cycle threshold of >22.0 on RT-PCR)^{Footnote 62}. Currently, neither of these therapeutics are licensed for use in Canada. As these monoclonal antibody treatments have been formulated against EBOV, they are not expected to be effective for the treatment of other orthoebolaviruses, including SUDV (the cause of the 2022-2023 Uganda outbreak).

The Association of Medical Microbiology and Infectious Diseases of Canada (AMMI Canada) along with the Canadian Critical Care Society and Canadian Association of Emergency Physicians have published guidelines pertaining to the care of patients with suspected and confirmed EBOD^{Footnote 63Footnote 64}. In addition, supportive treatment guidelines are available from the WHO^{Footnote 65}. Treatment of patients with confirmed EBOD in Canada will occur at a designated treatment centre, as directed by federal and provincial protocols.

Acknowledgements

This statement was prepared by the Ebola Working Group: Lagacé-Wiens P, Bui Y, Libman M (Chair), Pernica J, Vaughan S, Desroches M (CATMAT Secretariat) and approved by CATMAT.

CATMAT would like to thank Andrea K. Boggild, Anne E. McCarthy, Maryanne Crockett, and Jennifer Geduld for their contribution to earlier versions of the statement.

CATMAT acknowledges and appreciates the contributions of Jill Sciberras, Thomas Piggott, Nicole Pachal and Elspeth Payne to earlier versions of the statement.

CATMAT members: Libman M (Chair), Acharya A, Bogoch I, Bui Y, Greenaway C, Khatib A, Lagacé-Wiens P, Lee J, Plewes K, Vaughan S.

Liaison members: Angelo K (Centers for Disease Control and Prevention), Pernica J (Association of Medical Microbiology and Infectious Disease Canada), Viel-Thériault I (Canadian Paediatric Society).

Ex officio members: Marion D (Canadian Forces Health Services Centre, Department of National Defence), Rossi C (Medical Intelligence, Department of National Defence), Schofield S (Directorate Force Health Protection, Department of National Defence), and Zimmer R (Biologics and Radiopharmaceutical Drugs Directorate, Health Canada).

Conflict of interest

None declared.