Current Outbreak

Of the currently reported cases in the midwest United States, most experienced a prodrome consisting of fever, headaches, myalgias, chills, and drenching sweats. Roughly one-third of patients had a nonproductive cough. The prodromal phase was followed 1-10 days later by the development of a papular rash that typically progressed through stages of vesiculation, pustulation, umbilication, and crusting, and in some, ulceration. Rash distribution and lesions have occurred on head, trunk, and extremities; many of the patients had initial and satellite lesions on palms, soles and extremities.

Compared with previous reports of monkeypox among persons in central Africa, the illness associated with the current outbreak in the United States has been relatively mild. Monkeypox infection in adults has been described rarely in Africa; among adults, previous vaccination against smallpox might attenuate clinical illness. The report of encephalitis in a child indicates the potentially serious consequences of the disease. The potential risk to immunosuppressed persons should also be considered. Preliminary findings suggest that the primary route of monkeypox transmission to humans is from close contact with infected wild and exotic mammalian pets.