The Windsor‑Essex County Health Unit (WECHU) is advising healthcare providers of newly identified travel‑related cases of Mpox clade Ib in Ontario, representing the first detection of this variant in the province. Since 2022, Mpox activity in Ontario has been limited to the clade IIb strain. Clade Ib has been linked to outbreaks in parts of Central and Eastern Africa and has been identified in a small number of travel‑related cases internationally, including in several European countries. Currently, there is no evidence of Mpox activity in Windsor‑Essex County (WEC) and the risk to the public is low. 

Clinical Presentation and Testing
Common Mpox symptoms include fever, new rash/lesions in the mouth, genital, and/or peri-anal region, rectal pain, fatigue, and lymphadenopathy. Emerging evidence suggests that the clinical presentation of Mpox in vaccinated individuals may be more mild or subclinical. As a result, healthcare providers should consider Mpox as a differential diagnosis and ensure that at‑risk patients with compatible symptoms are tested.

Specimens should be taken from skin lesions in patients with a rash and rectal swab for those with rectal pain/lesions. Nasopharyngeal (NP) swabs can be used when a patient does not have a rash but present with other compatible signs and symptoms. Asymptomatic screening for Mpox by molecular assay is not indicated. Consult with Public Health Ontario (PHO) if you have questions regarding testing indications, specimen collection, or transportation. Testing for immunity (Mpox serology/antigen testing) is not available in Canada.

Transmission
Mpox spreads through:

• Direct contact with infected lesions, skin, or body fluids
• Respiratory secretions during prolonged close contact
• Contact with contaminated materials (e.g., clothing, bedding)
• Bites or scratches from infected animals

Individuals at Risk
Mpox has mainly, but not exclusively, affected the following individuals: 

• Two-Spirit, non-binary, transgender, cisgender, intersex, or gender-queer individuals who self-identify as belonging to the gay, bisexual, pansexual and other men who have sex with men (gbMSM) community and who meet one or more of the following:
  • have more than one partner
  • are in a relationship where at least one of the partners has other sexual partners
  • have had a confirmed sexually transmitted infection within the last year
  • have attended venues for sexual contact (e.g., bath houses, sex clubs)
  • have had anonymous sex recently (e.g., using hookup apps)
• Sexual partners of individuals who meet the criteria above
• Sex workers or who are a sexual contact of an individual who engages in sex work
• Staff or volunteers in sex-on-premises venues where workers may have contact with surfaces or objects that may be contaminated with Mpox
• Individuals who engage in sex tourism (regardless of gender, sex assigned at birth, or sexual orientation)
• Individuals who anticipate experiencing any of the above scenarios
• Research laboratory employees working directly with replicating Orthopoxviruses

Self-Isolation
The provincial guidance recommends self-isolation for all suspected and confirmed cases of Mpox. During case management, the WECHU will determine on a case-by-case basis when self-isolation can be discontinued. For more information, please refer to Recommendations for the Management of Cases and Contacts of Mpox in Ontario.

Treatment
The anti-viral tecovirimat (TPoxx®) is available for Mpox individuals who are severely ill due to Mpox infection or at high risk of experiencing severe illness (e.g., immunocompromised). To request TPoxx®, refer to the Mpox Antiviral Guidance for Health Care Providers.

Vaccinations
Imvamune® is a two-dose series, spaced apart for at least 28 days, that can be given to eligible individuals who are at risk for Mpox. Individuals who have received two doses do not require additional doses. Prior receipt of a smallpox vaccine does not replace Mpox vaccination. Vaccination remains free and does not require an OHIP card. Post‑exposure vaccination may be considered for eligible individuals following a known exposure. The provision of Imvamune® for post-exposure vaccination requires an assessment of the risk of exposure by the local public health unit. 

For more information, please visit Mpox Vaccines- WECHU website and Imvamune Product Monograph.

Key Actions for Health Care Providers 
Healthcare providers are asked to continue reporting all suspected and confirmed cases of Mpox to the WECHU using the appropriate reporting form. Completed forms may be faxed to 226‑783‑2132. Providers are also encouraged to proactively promote Mpox vaccination among eligible individuals and to reinforce completion of the recommended two‑dose Imvamune® vaccine series. Brief screening during sexual health visits, travel consultations, or other relevant encounters may help identify individuals who could benefit from vaccination. Healthcare providers[RD4]  interested in ordering and administering Imvamune®  are asked to place their order online using the WECHU online vaccine ordering system or to access the  order form available on our website.