• Consider diagnosis in person viral symptoms often with lymphadenopathy.
• Post-exposure vaccination using a single dose of Imvamune® used for high risk exposures to a probable or confirmed case of mpox. Ideally within 4 days (but up to 14 days) of last exposure.
• Public Health Numbers for Clinicians:
  • Fraser Health: 1-866-990-9941
  • Interior Health: 1-866-778-7736
  • Island Health:
    • South Island: 1-866-665-6626
    • Central Island: 1-866-770-7798
    • North Island: 1-877-887-8835
  • Northern Health: 250-645-3794
  • Vancouver Coastal Health: 604-675-3900

Background:

• Mpox is member of the poxviridae family which includes molluscum contagiousum and smallpox.
• WHO: Over 120 countries have reported mpox between Jan 2022 – Aug 2024, with over 100,000 laboratory-confirmed cases reported and over 220 deaths among confirmed cases.
• Since May 2022, there have been 231 confirmed mpox cases in BC: 190 cases in 2022, 20 in 2023 and 21 in 2024 to August 14. Rare hospitalizations. No deaths.
• Transmission through direct contact with infectious skin or lesions, respiratory droplets and possibly short-range aerosols.
• Potential transmission through contaminated clothing, linen.
• High proportion of cases identified in patients who identify as gay, bisexual and men who have sex with men – potentially related to positive health behaviours and strong connections to STI resources.

Monkeypox lesion. Photo: CDC

Clinical Presentation:

• Non-specific viral illness.
• First phase not consistently evident (1-5 days): fever, headache, myalgias, lymphadenopathy.
• Second phase (1-3 days): fever subsides and rash appears which progresses in a stereotypical fashion – macule, papule, vesicle, pustule, umbilicate lesion, crusting and desquamation (see https://www.cdc.gov/poxvirus/mpox/clinicians/clinical-recognition.html).
• Rash typically starts on the face and extended to the palms, soles and feet, mucous membranes – can skip palms/soles and be localized.
• 75% of cases in North America and Europe present initially with genital lesions.

Differential Diagnosis:

• Viruses: HSV, VSV, molluscum contagiousum.
• Bacteria: MRSA.
• STIs: syphilis, lymphogranuloma venereum, granuloma inguinale.

Management:

• Place patient in negative pressure room with airborne, droplet and contact precautions for all patient encounters.
• Call infection prevention and control, medical microbiology and infectious disease consulting services.
• Report case to regional public health office.
• Exposed contacts (including healthcare workers without adequate PPE) should self-monitor for 21 days.
• Lesions should be de-roofed and at least 2 lesions and an oropharyngeal swab should be taken using standard red collection tubes.
• Mainstay of treatment is supportive care and analgesia.
• If severe, Infectious Disease consultants may use Tecovirimat is an anti-viral available for the treatment of smallpox.
• As per the World Health organization, potential post-exposure prophylaxis with IMVAMUNE, a live attenuated, non-replicating smallpox vaccine up to 2 weeks after an exposure to a potential or confirmed case.

Treatment not recommended:

• Prophylactic antibiotics unless overlying skin and soft tissue infection.
• Do not de-roof lesions.

1. Nalca A, Rimoin AW, Bavari S, Whitehouse CA. Reemergence of monkeypox: prevalence, diagnostics, and countermeasures. Clin Infect Dis 2005; 41:1765.

   
   

2. World Health Organization. Monkeypox fact sheet. https://www.who.int/news-room/fact-sheets/detail/monkeypox (Accessed on August 28, 2024).

   
   

3. BC CDC: http://www.bccdc.ca/health-info/diseases-conditions/mpox (Accessed on August 28, 2024).

   
   

4. Public Health Agency of Canada (PHAC): https://www.canada.ca/en/public-health/services/diseases/mpox/outbreak-update.html (Accessed on August 28, 2024).

   
   

5. United States Centers for Disease Control and Prevention. https://www.cdc.gov/poxvirus/monkeypox/response/2022/world-map.html (Accessed on August 28, 2024).

   
   

6. Mauldin MR, McCollum AM, Nakazawa YJ, et al. Exportation of Monkeypox Virus From the African Continent. J Infect Dis 2022; 225:1367.

   
   

7. United States Centers for Disease Prevention and Control. Monkeypox: monitoring people who have been exposed. https://www.cdc.gov/poxvirus/monkeypox/clinicians/monitoring.html#exposure (Accessed on August 28, 2024).