Monkeypox (MPXV) is a virus from the same family as smallpox, that presents with a rash illness which may be mild and localised, or severe and disseminated (1):
- are 2 distinct clades of the virus:
- Clade I
- Clade I MPXV is currently considered more severe than Clade II MPXV, leading to its classification as a high consequence infectious disease (HCID)
- historically, Clade I MPXV has been reported only in 5 Central African countries
- in 2024, cases in additional countries within Central and East Africa mark the first known expansion of its geographical range, heightening the risk of spread beyond the region
- evidence of sustained sexual transmission of Clade I MPXV has emerged in the Democratic Republic of Congo (DRC)
- healthcare professionals should remain vigilant for Clade I MPXV, including in sexually acquired mpox cases, and should obtain comprehensive travel histories from patients
- Clade I MPXV can be subclassified as Clade Ia and Clade Ib (2)
- with clade Ia MPXV, transmission is thought to be driven by zoonotic exposure and subsequent household spread, with a substantial proportion of infections among children (2)
- with the emergence of the novel clade Ib MPXV, household spread and sexual transmission among people who are gay, bisexual, and other men who have sex with men as well as heterosexual networks are being described (2)
- Clade II
- Clade II MPXV is responsible for the global outbreak that began in 2022
Clinical features summary:
- symptoms of mpox begin 5 to 21 days (average 6 to 16 days) after exposure with initial clinical presentation of fever, malaise, lymphadenopathy and headache
- within 1 to 5 days after the appearance of fever, a rash develops, often beginning on the face or genital area and it may then spread to other parts of the body
- rash changes and goes through different stages before finally forming a scab which later falls off
Treatment for monkeypox is mainly supportive.
Clinical assessment and operational mpox HCID case definition
The following patients should be managed as HCID cases (pending confirmation of clade type where appropriate):
- confirmed mpox where Clade I MPXV has been confirmed
- confirmed or clinically suspected mpox, clade not yet known and:
- there is a travel history to the DRC or specified countries where there may be a risk of Clade I exposure
- or a link to a suspected case from those countries, within 21 days of symptom onset
- or there is an epidemiological link to a case of Clade I mpox within 21 days of symptom onset
Clinicians treating patients with suspected mpox who may meet the operational case definition of an HCID (as outlined above) should discuss this with local infection specialists
For up to date details then see https://www.gov.uk/guidance/monkeypox
Reference:
- UK Health Security Agency (August 16th 2024). Urgent public health message to all NHS service providers regarding Clade I mpox virus (MPXV) infection
- Titanji BK, Hazra A, Zucker J. Mpox Clinical Presentation, Diagnostic Approaches, and Treatment Strategies: A Review. JAMA. Published online October 14, 2024.