Monkeypox is a rare disease caused by the monkeypox virus, a type of orthopox virus related to variola and vaccinia viruses.
It is typically seen in Central and Western Africa. The natural reservoir is unknown, but is suspected to be rodents. Transmission of monkeypox virus occurs from animals to human through bites, scratches, or direct contact with animal body fluids. Human-to-human transmission is thought to occur primarily through large respiratory droplets and requires prolonged face-to-face contact. It can also occur through direct contact with body fluids or lesion material, or indirect contact through contaminated bedding or clothing.
Symptoms of monkeypox infection start approximately 7-14 days after exposure but can range from 5-21 days. Initial symptoms are typically flu-like including fever, headache, muscle and back aches, lymphadenopathy, chills, and exhaustion.
Within 1-3 days of the prodrome, the patient develops a rash, often beginning on the face then spreading to other parts of the body. Lesions typically begin to develop simultaneously and evolve together. The rash progresses through 4 stages – macular, popular, vesicular, to pustular – before scabbing over and resolving. This process happens over a period of 2-3 weeks.
Notably, in recent cases, the prodrome may or may not occur and lesions may be localized to the genital and perianal area.
Key Characteristics for Identifying Monkeypox
Lesions are well circumscribed, deep seated, and often develop umbilication
Lesions are relatively the same size and same stage of development on a single site of the body
Lymphadenopathy is common, may be generalized or localized, and is typically a distinguishing feature from smallpox
Disseminated rash is centrifugal with more lesions on the extremities and face
Lesions may occur on the palms and soles of the feet, and are often described as painful
Key features of the Rash
A person is contagious from the onset of the enanthem through the scab stage.
The first lesions to develop are on the tongue and in the mouth
1 - 2 days
Following the enanthem, a macular rash appears on the skin, starting on the face and spreading to the arms and legs and then to the hands and feet, including the palms and soles
The rash typically spreads to all parts of the body within 24 hours becoming most concentrated on the face, arms, and legs (centrifugal distribution)
1 - 2 days
By the 3rd day of rash, lesions have progressed from macular (flat) to popular (raised)
1 - 2 days
By the 4th to 5th day, lesions have become vesicular (raised and filled with clear fluid)
5 - 7 days
By the 6th to 7th day, lesions have become pustular (filled with opaque fluid), sharply raised, usually round, and firm to the touch (deep seated)
Lesions will develop a depression in the center (umbilication)
The pustules will remain for approximately 5 to 7 days before beginning to crust
7 - 14 days
By the end of the second week, pustules have crusted and scabbed over
Scabs will remain for about a week before beginning to fall off
Approval is required before any specimens can be tested for monkeypox. Clinicians should promptly report any suspect cases who are Chicago residents to CDPH by clicking on the following link: https://redcap.link/reportmpx. Reports will be reviewed by CDPH medical team and providers will be contacted for details about testing and submission of specimens to the IDPH laboratory. Providers should no longer email individual medical directors at CDPH.
A Job Aid is available for monkeypox testing here.
Personnel who collect specimens should use personal protective equipment (PPE) in accordance with recommendations for healthcare settings. The optimal PPE includes : gown, gloves, eye protection (e.g. goggles or a face shield that covers the front and sides of the face) and a NIOSH-approved N95 filtering facepiece or equivalent or a higher-level respirator
Use a sterile nylon, polyester, or Dacron swab with a plastic, or thin aluminum shaft. Flocked swabs or Eswabs are acceptable. Do not submit wooden or other types of swabs, or swabs in collection/tranport media.
Vigorously swab or brush lesion – if the skin atop the vesicle or pustule is intact, it may be necessary to gently lance and lift the lesion.
Place each specimen in a separate sterile container (e.g. by break off end of applicator of each swab into a 1.5- or 2-mL screw-capped tube with O-ring, or placing in a sterile urine cup, or 15cc/50cc conical tube). Do not add or store in viral or universal transport media.
Sample the same lesion 2 times, then repeat across 1 other location on the body or a lesion with a different appearance. Use a new swab for each specimen. Each specimen should be stored in its own container. Four specimens should be collected (two lesions, each collected twice).
Label each specimen container with:
Medical Record Number
Lesion Location (e.g. right foot, abdomen, left thigh)
Freeze (-20°C or lower) specimens within an hour after collection. If freezing is unavailable, refrigerate at (2–8°C).
Store refrigerated specimens for up to 7 days and frozen specimens for up to 60 days.
If testing is approved, CDPH will provide Requisition Forms, instructions on how to fill them out, and shipping instructions.
Standard Precautions should be applied for all patient care, including for patients with suspected monkeypox.
A patient with suspected or confirmed monkeypox infection should be placed in a single-person room; special air handling is not required. The door should be kept closed if safe to do so.
PPE used by healthcare personnel who enter the patient’s room should include : Gown, Gloves, Eye protection, NIOSH-approved N95 or equivalent respirator
Infection control guidance regadring home care of suspected or confirmed monkeypox cases can be found here.
Isolation and de-isolation
Persons with confirmed or suspected monkeypox infection should be isolated. Patients who do not require hospitalization, but remain potentially infectious to others, should be isolated at home.
Decisions regarding discontinuation of isolation precautions should be made in consultation with the individual’s provider. For individuals with monkeypox, isolation precautions in home settings should be continued until all lesions have resolved, the scabs have fallen off, and a fresh layer of intact skin has formed. Chicago Department of Public Health (CDPH) highly encourages persons with monkeypox be evaluated prior to discontinuing isolation. If necessary, the provider can reach out to CDPH for de-isolation recommendations.
Following the discontinuation of isolation precautions, affected individuals should avoid close contact with immunocompromised persons until all crusts are gone.
Immunocompromised persons include those whose immune mechanisms are
deficient because of:
Immunologic disorders (e.g., human immunodeficiency virus [HIV] infection or congenital immune deficiency syndrome)
Chronic diseases (e.g., diabetes, cancer, emphysema, or cardiac failure)
Immunosuppressive therapy (e.g., radiation, cytotoxic chemotherapy, anti-rejection medication, or steroids)
The antiviral Tecovirimat is available under investigational new drug (IND) protocol and should be considered for individuals meeting the following criteria:
Severe disease (e.g., hemorrhagic disease, confluent lesions, sepsis, encephalitis, or other conditions requiring hospitalization)
Those at high risk of severe disease:
Immunocompromised, including those with poorly controlled HIV
Pediatric populations, especially those <8 years old
Pregnant or breastfeeding women
Individuals with one or more complications (e.g., secondary bacterial skin infections; gastroenteritis with severe nausea/vomiting, diarrhea, or dehydration; broncho pneumonia, concurrent disease or other comorbidities)
Individuals with monkeypox infections that include mucosa (genitals, anus), or accidental implantation in the eyes or mouth.
Providers who identify patients with indications for Tecovirimat should reach out to CPDH by completing the following request form: https://redcap.link/mpxtreatment. CPDH will contact the provider for next steps for documentation to enroll in the IND program.