On August 14, the World Health Organization declared mpox to be a “public health emergency of international concern” (PHEIC) as an outbreak in the Democratic Republic of the Congo (DRC) worsened and caused fears of global spread. The WHO reports there have been more than 14,000 cases and 524 deaths related to mpox in more than a dozen countries across Africa this year.
In Canada, 164 cases have been reported to the federal government from January 1 to August 12.
Dr. Victor Leung, an infectious diseases physician at St. Paul’s Hospital, explains what mpox is and why the WHO made its declaration.
What is mpox?
Mpox is an infectious disease caused by the monkeypox virus, or MPXV. MPXV was originally identified in monkeys but the natural animal host for this virus remains unknown. The first human case of mpox (previously known as monkeypox) was identified in 1970 in the Democratic Republic of the Congo (DRC). MPXV is closely related to the variola virus, which causes smallpox.
How is it spread?
In a variety of ways. It can enter the human body though broken skin, mucous membranes, and the respiratory tract.
Animal-to-human transmission can occur when people have direct, close contact with infected animals during activities like hunting and slaughtering.
Human-to-human transmission also occurs during close contact. It can spread by touch directly, through physical contact, or indirectly, through shared objects. As a result, it can also be transmitted during sexual activity when there is intimate physical contact (skin to skin; skin to mucous membranes in the mouth and the genital tract).
Infected bodily fluids can also spread the virus if they are deposited (for instance, sprayed through breathing or coughing) on mucous membranes.
The exact extent of transmission via the respiratory route is not known. We know that infectious MPXV can linger in the air in small particles. These breathable respiratory particles (aerosols) can cause transmission.
Finally, there is mother-to-child transmission during pregnancy.
With multiple modes of transmission, in health care facilities, workers should use personal protective equipment that includes contact/droplet and airborne protection when they are treating patients with the virus.
Can it be fatal?
Yes, mpox can be fatal. The fatality rate is dependent on the human host risk factors. It also appears to be related to certain types of MPXV.
What are the symptoms?
Mpox usually shows up in the invasive phase when the virus is replicating and causing symptoms such as fever, headaches, fatigue, and muscle aches. At this stage, there may also be swollen lymph nodes.
A rash will develop two or three days later. The skin lesions develop and can form fluid or pus-filled pox lesions.
The rash can be on any part of the body. The number of skin lesions can vary from a few to thousands. They can be itchy and painful.
With more cases and different strains, there are reports of less typical presentations (example: absence of the invasive phase symptoms and just a new onset of rash).
Why did WHO declare a Public Health Emergency of International Concern (PHEIC)?
The declaration was based on the criteria under the International Health Regulation assessment of the current outbreak of mpox.
The criteria included:
- Extraordinary event: A surge in the number of cases caused by a new strain (also known as a clade) of the MPXV affecting a higher number of women and children.
- Risk of International spread: There is already spread of the this virus (Clade 1b) from the Democratic Republic of the Congo to neighboring countries, including Burundi, Rwanda, Kenya and Uganda. After the PHEIC was declared, cases have been found in Sweden – the first outside Africa.
- The need for a coordinated international response: The resources for diagnosis and case finding, as well as for vaccination and prevention of further spread need to be redirected to countries with the highest risk of transmission to achieve containment of this outbreak.
What is a “global health emergency” and what does it mean to us in Canada?
It means that Canada needs to assess the resources we have to determine what can be redirected to countries at the highest risk for transmission.
For instance, Canada must determine how much stockpiled vaccine can be redirected in a coordinated manner to affected countries in Africa.
Are people who live in Canada at risk?
A 2022 outbreak of mpox caused by MPXV Clade 2b also saw the WHO declare a global health emergency. Canada continues to have new cases related to this. If the outbreak from MPXV Clade 1B cannot be contained, people in Canada will be at risk. We live in an interconnected world. People travel. A risk in one part of the world will not be contained there if transmission is not controlled.
Are some communities/age groups more at risk than others?
In the mpox global outbreak of 2022, the majority of infected people were men. A large proportion were gay or bisexual men who have sex with men.
The current outbreak in the DRC and neighboring countries is affecting women and children as well. The number of fatalities reported appears to be highest in children.
Is there a vaccine in Canada?
The only vaccine for Mpox in Canada is the Imvamune vaccine. It is a vaccinia virus vaccine that is used for protection against smallpox. Currently, Imvamune is reserved for highest risk groups.
Visit the Canada Immunization Guide for details.
What should I do if I’m diagnosed with it?
See a physician for treatment. You’ll be connected with a public-health team that will help manage any high-risk contacts you may have.
How is it treated?
Treatment is administered to manage symptoms like itching and pain, along with complications like infections. There are ongoing studies to determine if an antiviral medication known as Tecovirimat is useful in reducing severity and duration of illness.
Do some people need to be hospitalized?
Yes, some may, depending on how serious the case is. In 2022 when British Columbia had its first mpox patient, the person had a short hospital stay.
For more information, visit Healthlink BC or this WHO Fact Sheet.
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