Scourge

In the wild, it came in two distinct varieties. Variella major caused a serious disease that killed between 10% and 30% of its victims. Whereas variella minor gave rise to a much milder illness called elastrim, with a case mortality rate of less than 1%. Because the two types of smallpox virus produced similar symptoms, it is not known why one was so much more lethal than the other. Now confined to a few laboratory freezers, variella major once rampaged through the human species and caused the most feared of deadly scourges. After a two-week incubation period, smallpox wracked the body with high fever, headache, backache and nausea, and then peppered the face, trunk, limbs, mouth and throat with hideous, pus-filled boils. Patients with the infection were in agony. Their skin felt as if it was being consumed by fire. And although they were tormented by thirst, lesions in the mouth and throat made it excruciating to swallow. The odor of a smallpox ward was oppressive. The rash gave off a sweetish, pungent smell, reminiscent of rotting flesh. For those who survived, the disease ran its course in a few weeks. Pustule formation concluded on days 8 to 10 of the illness, after which the boils scabbed over and were gradually reabsorbed. On days 15 to 20, the crusty dry scabs separated and fell off, leaving depigmented areas of skin that later turned into ugly, pitted scars. Even as smallpox victims were suffering the torments of the disease, they were spreading it to others. Lesions in the patient's mouth and throat shed millions of virus particles into the saliva and mucus, so that talking or sneezing expelled virus-laden droplets that floated in the air and could be inhaled. The virus was also present in patient's urine and in pus from unhealed skin lesions. When clothing and bed linens contaminated with dried pus were handled, virus particles could be re-suspended in the air, so that laundry workers who washed the sheets and blankets of smallpox patients were at great risk of infection. The corpses of smallpox victims were also dangerously contaminated and could spread the disease to undertakers or to family members who prepared a loved one's body for ritual burial. Over the course of human history, smallpox claimed hundreds of millions of lives, far more than plague, the dreaded Black Death of the Middle Ages, and all the wars of the 20th century combined. Although those lucky enough to survive a bout with smallpox acquired lifelong immunity, they usually suffered some type of permanent damage. Nearly all were disfigured with pockmarks, and one in ten was rendered partially or completely blind. In addition, smallpox significantly increased the risk of miscarriage in pregnant women. As recently as 1967, the disease sickened between 10 million and 15 million people each year in 43 countries and caused an estimated 2 million deaths. On May 8, 1980, however, the World Health Organization, WHO, declared that humanity had finally been freed from the torments of smallpox, the culmination of a global campaign lasting more than a decade and employing up to 150,000 health workers at various times. The conquest of smallpox, the first and so far only infectious disease to have been eradicated from nature by human effort, was among the greatest medical achievements of the 20th century. After the WHO formally certified the eradication of smallpox in May 1980, all member countries agreed to stop vaccinating their civilian populations because the potential risk of complications from the vaccine now outweighed the tiny chance that smallpox might re-emerge from natural sources. Since then, the horrors of the disease have faded from public consciousness like the memory of a nightmare. Fewer and fewer individuals bear the round, mottled scar of a smallpox vaccination on their upper arm or thigh, let alone the disfiguring pockmarks that were once the hallmark of the disease. But although some would relegate the history of smallpox to the dusty shelves of a medical library, such complacency would be premature. In 1992, a senior Russian official defected to the United States and told the CIA that the Soviet Union, even as it had supported the smallpox eradication campaign with vaccine and expertise, had secretly developed the virus into a military weapon and stockpiled enough of it to kill millions of people. News of the Soviet betrayal sparked official concern in Washington, London and other capitals that samples of the virus might fall into the hands of rogue states and terrorist organizations. Because the immunity induced by the smallpox vaccine fades after about a decade, most of the world is now susceptible to infection. Responding to this potential threat, the United States and other countries are undertaking urgent efforts to strengthen their medical defenses against this supposedly eradicated disease. Every human being on the planet has a stake in the fate of the smallpox virus. For we are all.