Variola, or smallpox, is an acute, highly contagious infectious disease caused by the poxvirus variola. After a global eradication program, the World Health Organization pronounced it eradicated on October 26, 1979, 2 years after the last naturally occurring case was reported in Somalia. Vaccination is now being reconsidered in light of potential biological attacks. The Centers for Disease Control and Prevention is actively involved in plans for both pre-emptive and emergency vaccination.
Variola 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 that occurred in previously vaccinated people who had only partial immunity.
CLINICAL TIP: Hemorrhagic variola, an uncommon form of variola major, has a much shorter incubation period, making initial recognition as variola unlikely. It’s usually fatal and vaccination doesn’t provide much protection.
Variola can affect people of all ages. Before its eradication, incidence was highest during the winter in temperate zones; during the hot, dry months in the tropics. It’s transmitted directly by respiratory droplets or dried scales of virus-containing lesions or indirectly through contact with contaminated linens or other objects. In a terrorist attack, exposure would most likely occur through inhalation.
CLINICAL TIP: Variola major is contagious from onset until after the last scab is shed. Individuals infected with variola minor and varioloid are infectious at the appearance of the first rash and remain contagious until the last variola scab falls off.
Characteristically, after an incubation period of 10 to 14 days, variola causes 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 become more severe, but by the third day the patient begins to feel better.
However, symptoms persist. The patient develops a sore throat and cough as lesions begin to appear on the mucous membranes of the mouth, throat, and respiratory tract. Within days, skin lesions appear, progressing from macular to papular, vesicular, and pustular (pustules may be as large as 1/3'' [8 mm] in diameter). During the pustular stage, the patient’s temperature again rises, and early symptoms return. By day 10, the pustules begin to rupture and eventually dry and form scabs. Symptoms finally subside about 14 days after onset. Desquamation of the scabs takes another 1 to 2 weeks, causing intense pruritus and commonly leaving permanently disfiguring scars.
In fatal cases, a diffuse dusky appearance comes over the patient’s face and upper chest. Death results from encephalitic manifestations, extensive bleeding from any or all orifices, or secondary bacterial infections.
Variola is readily recognizable, especially during an epidemic or after a known contact. The most conclusive laboratory test is a variola virus culture 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 virus antibodies in the patient’s blood.
Treatment requires hospitalization with strict isolation, antimicrobial therapy to treat bacterial complications, vigorous supportive measures, and symptomatic treatment of lesions with antipruritics, starting during the pustular stage. Anti-inflammatories, codeine or, as needed, morphine relieve pain; intravenous infusions and gastric tube feedings provide fluids, electrolytes, and calories because pharyngeal lesions make swallowing difficult.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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Title: Handbook of Diseases Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2003 ISBN: 1-58255-266-5 
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