Case definition

Confirmed case

A person who is laboratory confirmed for mpox (monkeypox) virus by detection of unique sequences of viral DNA either by real-time polymerase chain reaction (PCR) and/or sequencing.

Probable case

A person who presents with an unexplained¹ acute rash or lesion(s)²

AND

Has one or more of the following in the 21 days before symptom onset:

• Has an epidemiological link to a probable or confirmed mpox case,
• Has an epidemiological link to a location/event where transmission of mpox is suspected or known to have occurred,
• Epidemiological link such as:
• Direct physical contact, including sexual contact; or contact with contaminated materials such as clothing or bedding
• face-to-face exposure, including health workers without appropriate personal protective equipment (PPE)

AND

Mpox virus has not been ruled out by an Orthopoxvirus or mpox virus PCR (i.e. laboratory testing is not available)

Suspect case

A person in whom mpox virus has not yet been ruled out by a negative Orthopoxvirus or mpox virus PCR result who presents with one or more of the following:

• An unexplained¹ acute rash² AND has at least one of the following signs or symptoms
• headache
• acute onset of fever (>38.5°C)
• lymphadenopathy (swollen lymph nodes)
• myalgia
• back pain
• asthenia (profound weakness)
• An unexplained¹ acute genital, perianal or oral lesion(s)

NOTES

1. Common causes of acute rash can include varicella zoster, herpes zoster, measles, herpes simplex, syphilis, chancroid, lymphogranuloma venereum, hand-foot-and-mouth disease.

2. Acute rash
Mpox illness includes a progressively developing rash that usually starts on the face and then spreads elsewhere on the body. The rash can affect the mucous membranes in the mouth, tongue, and genitalia. The rash can also affect the palms of hands and soles of the feet. The rash can last 2 to 4 weeks and progresses through the following stages before falling off:

• macules
• papules
• vesicles
  
• pustules
• scabs

N.B. It is not necessary to obtain negative laboratory results for listed common causes of rash illness in order to classify a case as suspected.