Smallpox: Background information when reading I Am Pilgrim

Smallpox

This article relates to I Am Pilgrim

In I Am Pilgrim, the villain attempts to infect a large number of people with a genetically engineered version of smallpox — a deadly disease completely eradicated by 1977.

Smallpox is caused by the variola virus, which is believed to have been around since approximately 10,000 BCE. As it progresses, victims develop a rash which turns into pustules (hence the common name "pox"). The most common form of smallpox was caused by the virus Variola major, representing about 90% of cases with a fatality rate of about 30%. There is no cure for smallpox, only a preventative vaccine.

Smallpox is an airborne disease, with transmission occurring through direct, prolonged face-to-face contact (the Centers for Disease Control estimates it's necessary to be in contact with the infected individual for at least three hours). It can also be spread through contact with infected bodily fluid or contaminated objects such as clothing or bedding. Casual contact such as sharing a bus ride with an infected person is not enough to contract the disease, and it's considered much less contagious than the flu, measles or whooping cough. It is not known to be transmitted by insects or animals; humans are the only known host.

The disease progresses through several phases:

• Incubation: This is the time between when the person is infected and when symptoms begin to appear. It generally lasts 12 to 14 days, but can be as brief as one week or as long as 17 days. During this time, the individual is not contagious.
• Initial symptoms: This phase can be mistaken for the flu, as the symptoms (fever, head and body aches, fatigue and sometimes vomiting) are similar. This stage lasts for two to four days, and the person may be contagious during it.
• Early rash: At this point, small red spots appear on the tongue and in the mouth. The spots develop into sores which break open and spread the disease. The rash generally appears first on the face and then spreads to the arms and legs before covering the entire body within 24 hours of the mouth sores breaking. The patient may actually feel considerably better than they had, since the fever abates during this phase. The rash becomes raised bumps three days after initial symptoms. After four days, the fever spikes again and the bumps fill with a thick, opaque fluid, and they often develop a depression in the center that looks like a belly button (this is the major distinguishing characteristic of smallpox). The early rash phase is the most contagious stage, and lasts approximately four days.
• Pustular rash: According to the CDC, "The bumps become pustules – sharply raised, usually round and firm to the touch as if there's a small round object under the skin. People often say the bumps feel like BB pellets embedded in the skin." This phase lasts five days, and the person remains contagious.
• Pustules and scabs: During this time period (approximately five days) the pustules start to scab over.
• Resolving scabs: The scabs start to fall off leaving pitted scars. The patient remains contagious until all the scabs have fallen off. The disease has run its course three weeks after initial symptoms appeared (and five weeks after infection).

The above describes the course of most cases of smallpox; but it did also take other forms including a relatively benign variant caused by the Variola minor virus; and two almost always fatal forms - malignant and hemorrhagic smallpox. Overall, about 3 in every 10 who contracted the disease died from a variety of complications including pneumonia and organ failure. Those who developed pustules on their eyes were also at risk of blindness.

The CDC states that "Except for laboratory stockpiles, the variola virus has been eliminated." The last known case of smallpox in the United States occurred in 1949, and the last naturally occurring case appeared in Somalia in 1977. The public is consequently no longer being vaccinated against smallpox. Nevertheless, in response to the 9/11 terrorist attacks and an anthrax scare in October 2001, the United States government has prepared a response plan. Its guidelines state that even one smallpox case would be enough for the CDC to declare a public health emergency and would require rapid response.

Given the slow infection rate, it's estimated that one person would spread the disease to five others (generally close family members), which would in turn spread the disease (over five "generations") to a total of approximately 3,125 people before health measures would stop it. The plan includes vaccinating those around the infected individual in a protective "ring" so that the infection is quickly contained, although enough vaccine has been stockpiled to vaccinate every US citizen should smallpox resurface.

Picture of variola virus by Dr. Fred Murphy; Sylvia Whitfield at the Centers for Disease Control

Filed under Medicine, Science and Tech

This article relates to I Am Pilgrim. It first ran in the June 4, 2014 issue of BookBrowse Recommends.