Monkeypox: Canadian outbreak update

June 16, 2022

 

Background

Monkeypox is a rare viral disease caused by monkeypox virus (genus orthopox), related to, but distinct from smallpox and cowpox1. This virus is usually found in central and western Africa, with two genetically distinct clades1. The West African clade has limited human-to-human transmission, and case fatality of 1%, where the Congo Basin clade is associated with human-to-human transmission, with a case fatality reported at 10%1. On May 13, 2022, the United Kingdom (UK) notified the WHO about the presence of the West African clade of the virus in the UK, and on May 19, 2022, the Public Health Agency of Canada confirmed the first two human cases of monkeypox in Canada1.

Transmission

Risk of community spread of monkeypox remains very low and is limited to close, direct contact with infected persons, animals, or objects2. Person to person spread may occur through contact with skin lesions, blood, bodily fluids, and mucosal surfaces2. Transmission may also occur by contact with non-intact skin or scabs, indirect contact with clothing or linens used by an infected person, or close contact with respiratory tract secretions of a person with monkeypox1. Sexual transmission has not been previously known as a mode of transmission, however, close direct contact with sexual partners infected with monkeypox can result in transmission of the virus1. Asymptomatic spread of monkeypox is extremely uncommon2. It is unknown at this time if airborne transmission of monkeypox occurs, however, with evidence of smallpox airborne transmission, there is still concern that monkeypox may be transmitted by the airborne route1.

Symptoms and Management

Symptoms of monkeypox are generally mild and infected patients will recover on their own after approximately four weeks3. The incubation period of monkeypox is typically 6-13 days; however, patients can develop symptoms in a range of 5-21 days after exposure to the virus3. Monkeypox infection occurs in two stages of illness, lasting between 2-4 weeks3. In the first stage of illness, patients will develop fever, chills, swollen lymph nodes, headache, muscle, joint, and back pain, and exhaustion3. The second stage of illness usually occurs between 1-3 days after the occurrence of fever3. Patients will develop a rash that often starts on the face and extremities, mouth, or genitals3. This rash will last between 14-28 days and will resolve when scabs will form and eventually fall off3. Most cases of monkeypox are mild and self-limiting, however some severe cases may occur. Treatment for monkeypox is mainly supportive care, there are no established treatments at this time3.

Infection Prevention and Control

Although airborne transmission of monkeypox is currently unknown, healthcare settings should implement droplet, contact, and airborne precautions for suspect, probable, and confirmed cases of monkeypox until more information on transmission is known1. Precautions should be used with all patients presenting with fever and a vesicular, pustular rash1. Patients with known or suspected monkeypox should practice hand hygiene, wear a medical mask, and have their skin lesions covered with a gown, clothing, bedsheets, or bandages1. Infected patients should be isolated in an airborne infection isolation room (AIIR), or a single room with the door closed1. When providing care to patients with suspected or confirmed monkeypox, healthcare providers should wear a fitted N95 mask, gown, gloves, and eye protection1. All PPE worn while in contact with the patient must be discarded after each contact1. It should be assumed that the patient is contagious until scab crusts fall off and new skin is formed (approximately 3-4 weeks)1.

Canadian Outbreak Update

As of June 10, 2022, at 11:00 am EDT Canada has reported 112 cases of monkeypox4. Provinces reporting cases include British Columbia (1 case), Alberta (4 cases), Ontario (9 cases), and Quebec (98 cases)4. Other countries where monkeypox is non-endemic have been reporting cases. The WHO provides global updates on their website, found here (Multi-country monkeypox outbreak in non-endemic countries (who.int)). Canada’s Chief Public Health Officer has been working in close contact with provincial and territorial Chief Medical Officers, while Canada’s National Microbiology Laboratory is performing diagnostic testing and whole genome sequencing of the monkeypox virus4.
Canadian monkeypox outbreak updates can be found here (Monkeypox: Outbreak update - Canada.ca), with updates provided each week on Tuesdays and Thursdays. 

References

  1. Public Health Agency of Canada. Government of Canada. Interim guidance on infection prevention and control for suspect, probable or confirmed monkeypox within healthcare settings. Canada.ca. https://www.canada.ca/en/public-health/services/diseases/monkeypox/health-professionals/interim-guidance-infection-prevention-control-healthcare-settings.html. Published June 1, 2022. Accessed June 10, 2022.
  2. Public Health Agency of Canada. Government of Canada. Monkeypox: Risks. Canada.ca. https://www.canada.ca/en/public-health/services/diseases/monkeypox/risks.html. Published June 1, 2022. Accessed June 10, 2022.
  3. Public Health Agency of Canada. Government of Canada. Monkeypox: Symptoms and management. Canada.ca. https://www.canada.ca/en/public-health/services/diseases/monkeypox/symptoms-management.html. Published June 8, 2022. Accessed June 10, 2022. 
  4. Public Health Agency of Canada. Government of Canada. Monkeypox: Outbreak update. Canada.ca. https://www.canada.ca/en/public-health/services/diseases/monkeypox.html. Published June 9, 2022. Accessed June 10, 2022.