SMALLPOX

Smallpox is an infection caused by the variola virus, a member of the poxvirus family. Throughout history, smallpox has caused huge epidemics resulting in great suffering and enormous death tolls worldwide. In 1980, the World Health Organization (WHO) announced that a massive program of vaccination against the disease had resulted in the complete eradication of the virus (with the exception of stored virus stocks in two laboratories).

Smallpox is an extraordinarily contagious disease. The virus can spread by contact with victims, as well as in contaminated air droplets and even on the surfaces of objects used by other smallpox victims (books, blankets, etc.). After acquisition of the virus, there is a 12–14 day incubation period, during which the virus multiplies, but no symptoms appear. The onset of symptoms occurs suddenly and includes fever and chills, muscle aches, and a flat, reddish-purple rash on the chest, abdomen, and back. These symptoms last about three days, after which the rash fades and the fever drops. A day or two later, the fever returns, along with a bumpy rash starting on the feet, hands, and face. This rash progresses from the feet along the legs, from the hands along the arms, and from the face down the neck, ultimately reaching and including the chest, abdomen, and back. The individual bumps, or papules, fill with clear fluid, and, over the course of 10–12 days, became pus-filled. The pox eventually scabs over, and when the scab falls off it leaves behind a pock-mark or pit, which remains as a permanent scar on the skin of the victim.

Death from smallpox usually follows complications such as bacterial infection of the open skin lesions, pneumonia, or bone infections. A very severe and quickly fatal form of smallpox was "sledgehammer smallpox," and resulted in hemorrhage from the skin lesions, as well as from the mouth, nose, and other areas of the body. No treatment was ever discovered for smallpox nor could anything shorten the course of the disease. Up until its eradication, smallpox was diagnosed most clearly from the patients' symptoms. Electron microscopic studies could identify the variola virus in fluid isolated from disease papules, from infected urine, or from the blood prior to the appearance of the papular rash.

Smallpox is an ancient disease. There is evidence that a major epidemic occurred towards the end of the eighteenth Egyptian dynasty. Studies of the mummy of Pharaoh Ramses V (d. 1157 B.C. ) indicate that he may have died of smallpox. Several historical accounts, some dating to the sixth century, describe how different peoples attempted to vaccinate against smallpox. In China, India, and the Americas, from about the tenth century, it was noted that individuals who had even a mild case of smallpox could not be infected again. Material from people ill with smallpox (e.g., fluid or pus from the papules) was scratched into the skin of those who had never had the illness, in an attempt to produce a mild reaction and its accompanying protective effect. These efforts often resulted in full-fledged smallpox, and sometimes served only to effectively spread the infection throughout the community. In Colonial America, such crude vaccinations against smallpox were outlawed because of the dangers.

In 1798, Edward Jenner (1749–1823) published a paper in which he discussed an important observation that milkmaids who contracted a mild infection of the hands (caused by vaccinia virus, a relative of variola) appeared to be immune to smallpox. He created an immunization against smallpox that used the pus material found in the lesions of cowpox infection. Jenner's paper, although severely criticized at first, later led to much work in the area of vaccinations. Vaccination using Jenner's method proved instrumental in decreasing the number of smallpox deaths.

Smallpox is dangerous only to human beings. Animals and insects can neither be infected by smallpox, nor carry the virus in any form. Humans also cannot carry the virus unless they are symptomatic. These important facts entered into the decision by the WHO to attempt worldwide eradication of the smallpox virus. The methods used in the WHO eradication program were simple and included the careful surveillance of all smallpox infections worldwide to allow for quick diagnosis and immediate quarantine of patients. It also included the immediate vaccination of all contacts of any patient diagnosed with smallpox infection. The WHO program was extremely successful, and the virus was declared eradicated worldwide in May of 1980. Two laboratories (in Atlanta, Georgia and in Koltsovo, Russia) retain samples of the smallpox virus, because some level of concern exists that another poxvirus could mutate (undergo genetic changes) and cause human infection. Other areas of concern include the possibility of smallpox virus being utilized in a situation of biological warfare, or the remote chance that the smallpox virus could somehow escape from the laboratories where it is being stored. For these reasons, large quantities of vaccine are stored in different countries around the world, so that response to any future threat by the smallpox virus can be prompt.