Variola, or smallpox, was an acute, highly contagious infectious disease caused by the poxvirus variola. After a global eradication program, the World Health Organization pronounced smallpox eradicated on October 26, 1979, 2 years after the last naturally occurring case was reported in Somalia. Vaccination is no longer recommended, except for certain laboratory workers. The last known case in the United States was reported in 1949. Although naturally occurring smallpox has been eradicated, variola virus preserved in laboratories remains an unlikely source of infection. In response to bioterrorism concerns, smallpox vaccination was offered to members of the military, health department officials, first responders, and key health care providers. If a bioterrorism event involving smallpox is suspected or occurs, vaccination programs can be initiated.
Smallpox developed in three major forms: variola major (classic smallpox), which carried a high mortality; variola minor, a mild form that occurred in nonvaccinated people and resulted from a less virulent strain; and varioloid, a mild variant of smallpox that occurred in previously vaccinated people who had only partial immunity.
Smallpox affected people of all ages. In temperate zones, incidence was highest during the winter; in the tropics, during the hot, dry months. Smallpox was transmitted directly by respiratory droplets or dried scales of virus-containing lesions or indirectly through contact with contaminated linens or other objects. Variola major was contagious from onset until after the last scab was shed.
Characteristically, after an incubation period of 10 to 14 days, smallpox caused an abrupt onset of chills (and possible seizures in children), high fever (above 104° F [40° C]), headache, backache, severe malaise, vomiting (especially in children), marked prostration and, occasionally, violent delirium, stupor, or coma. Two days after onset, symptoms became more severe, but by the third day the patient began to feel better.
However, he soon developed a sore throat and cough as well as lesions on the mucous membranes of the mouth, throat, and respiratory tract. Within days, skin lesions also appeared, progressing from macular to papular, vesicular, and pustular (pustules were as large as 8.5 mm in diameter). All skin lesions were in the same stage of development. During the pustular stage, the patient's temperature again rose, and early symptoms returned. By day 10, the pustules began to rupture and eventually dried and formed scabs. Symptoms finally subsided about 14 days after onset. Desquamation of the scabs took another 1 to 2 weeks, caused intense pruritus, and commonly left permanently disfiguring scars.
In fatal cases, a diffuse dusky appearance came over the patient's face and upper chest. Death resulted from encephalitic manifestations, extensive bleeding from any or all orifices, or secondary bacterial infections.
Before the global eradication program, smallpox was readily recognizable, especially during an epidemic or after known contact. However, most of today's health care workers aren’t familiar with the disease’s telltale signs and symptoms. The most conclusive laboratory test is a culture of variola virus isolated from an aspirate of vesicles and pustules. Other laboratory tests include microscopic examination of smears from lesion scrapings and complement fixation to detect virus or antibodies to the virus in the patient's blood.
Treatment for smallpox requires hospitalization with droplet and contact precautions, antimicrobial therapy to treat bacterial complications, vigorous supportive measures, and symptomatic treatment of lesions with antipruritics, starting during the pustular stage. If the smallpox vaccination is given within 1 to 4 days of exposure to the disease, it may prevent illness or lessen symptoms. Treatment once the disease has started is limited.
❑Give aspirin, codeine, or (as needed) morphine to relieve pain.
❑ I.V. infusions and gastric tube feedings provide fluids, electrolytes, and calories because pharyngeal lesions make swallowing difficult.
❑If smallpox is suspected, the state health department should be notified immediately.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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Title: Professional Guide to Diseases (Eighth Edition) Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2005 ISBN: 1-58255-370-X 
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