smallpox

An acute eruptive contagious disease caused by a poxvirus (Orthopoxvirus, a member of the family Poxviridae) and marked at the onset by chills, high fever, backache, and headache; in 2–5 days the constitutional symptoms subside and an eruption appears as papules, which become umbilicated vesicles, develop into pustules, dry, and form scabs that, on falling off, leave a permanent marking of the skin (pock marks); average incubation period is 8–14 days. As a result of increasingly aggressive vaccination programs carried out over a period of about 200 years, s. is now extinct. SYN: variola major, variola. [E. small pocks, or pustules] S. was a universally dreaded scourge for more than 3 millennia, with case fatality rates sometimes exceeding 20%. In many ways a unique disease, it had no nonhuman reservoir species and no human carriers. First subjected to some control by variolation in the 10th century in India and China, it was gradually suppressed in the industrialized world after Edward Jenner's 1776 landmark discovery that infection with the harmless cowpox (vaccinia) virus renders humans immune to the s. virus. A global eradication program was initiated by the World Health Organization in 1966, and the last naturally occurring case of the disease was reported in Somalia in 1977. The disease is now of mainly historical interest.

- confluent s. a severe form in which the lesions run into each other, forming large suppurating areas.

- discrete s. the usual form in which the lesions are separate and distinct from each other.

- fulminating s. SYN: hemorrhagic s..

- hemorrhagic s. a severe and frequently fatal form of s. accompanied by extravasation of blood into the skin in the early stage, or into the pustules at a later stage, accompanied often by nosebleed and hemorrhage from other orifices of the body. SYN: fulminating s., variola hemorrhagica.

- malignant s. SYN: variola maligna.

- modified s., varicelloid s. SYN: varioloid (2).

- West Indian s. SYN: alastrim.

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small·pox 'smȯl-.päks n an acute contagious febrile disease of humans that is caused by a poxvirus of the genus Orthopoxvirus (species Variola virus), is characterized by skin eruption with pustules, sloughing, and scar formation, and is believed to have been eradicated globally by widespread vaccination called also variola see VARIOLA MAJOR, VARIOLA MINOR

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n.

an acute infectious virus disease causing high fever and a rash that scars the skin. It is transmitted chiefly by direct contact with a patient. Symptoms commence 8-18 days after exposure and include headache, backache, high fever, and vomiting. On the third day, as the fever subsides, red spots appear on the face and spread to the trunk and extremities. Over the next 8-9 days all the spots (macules) change to pimples (papules), then to pea-sized blisters that are at first watery (vesicles) but soon become pus-filled (pustules). The fever returns, often causing delirium. On the eleventh or twelfth day the rash and fever abate. Scabs formed by drying out of pustules fall off 7-20 days later, leaving permanent scars. The patient remains infectious until all scabs have been shed. Most patients recover but serious complications, such as nephritis or pneumonia, may develop. Treatment with thiosemicarbazone is effective. An attack usually confers immunity; immunization against smallpox has now totally eradicated the disease. Medical name: variola. See also alastrim, cowpox.

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small·pox (smawlґpoks) [compared to “great pox” (syphilis)] an acute, highly contagious, often fatal infectious disease caused by an orthopoxvirus. Vaccination has succeeded in eradicating smallpox worldwide; therefore, since there are no animal vectors of the disease, the only source of the virus is in medical laboratories. In the usual form, after an incubation period and a prodrome of high fever, chills, myalgia, and malaise, petechial reddish spots would appear on the oral mucosa followed by a raised macular cutaneous rash starting on the forehead and spreading to become generalized. The lesions would evolve to become papules and vesicles, umbilicate, crust, and scab, leaving small depressed, depigmented scars called pockmarks. Varieties included hemorrhagic smallpox and variola minor. Called also variola.

Smallpox.