Transmission: Monkeypox is spread in humans primarily from direct contact with the virus from an infected person’s skin sores, scabs, or body fluids. It can be spread indirectly, to a lesser degree through materials contaminated with the virus. Transmission from respiratory secretions likely requires oral lesions and prolonged close contact. Animal to human spread can occur from an infected animal’s body fluids or bite.
Most reported cases have occurred in persons who have had close, sustained, intimate skin-to-skin contact with the lesions (or fluid from lesions) from an infected person.
The CDC reports that most cases of monkeypox in the U.S. have occurred among gay, bisexual, trans, and other men who have sex with men (MSM). At the time of this post, the number of monkeypox cases are doubling on a weekly basis. At the current rate, it is more than likely the condition will extend to the general public. The take home message, regardless of one’s sexual orientation, is to avoid social settings that bring people in close skin-to-skin contact (crowded dance floors, music festivals, etc.) or intimacy with a person who has an unexplained rash.
Monkeypox is not spread easily from person to person through casual contact. The overall risk to the public is low and will remain so as long as they are mindful of the conditions that spread the virus.
It is currently not known:
- If the virus can be spread when someone has no symptoms.
- Whether monkeypox can be spread through semen, vaginal fluids, urine, or feces.
- What degree can monkeypox can be spread through respiratory secretions.
Clinical Illness: The incubation period (time from exposure to the virus to the time first symptoms appear) varies from 5 days to as long as 21 days. For the current outbreak, the mean incubation period is 8.5 days, during which time the person feels fine and does not have symptoms.
Symptoms: The initial set of symptoms (prodrome) are the development of flu-like symptoms (fever, chills, headache, swollen lymph nodes, severe fatigue) with the characteristic rash appearing 1-4 days later. Some persons can develop the rash prior to the flu-like symptoms, while others just develop a rash as the only manifestation of the infection.
The typical rash progresses through several stages over 1-2 weeks: the rash begins with pink macules (round, flat lesions, 2-5 mm diameter), which progress to raised, round fleshy bumps (papules), to fluid-filled lesions (vesicles), to cloudy-fluid filled raised lesions (pustules), often with a central dimple “umbilication”, followed by the lesion drying up and scabbing.
Persons with flu-like symptoms who do not develop a rash by day 5 are unlikely to have monkeypox.
Monkeypox may be spread during the prodromal stage (fever, lymphadenopathy, etc.), but is most contagious with the appearance of the rash, where one can spread the virus until the rash has healed, all scabs have fallen off, and a fresh layer of skin has formed. The illness typically lasts 2-4 weeks.
