Smallpox overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Smallpox is a contagious disease unique to humans.[1] Smallpox is caused by either of two virus variants named Variola major and Variola minor. The deadlier form, V. major, has a mortality rate of 30–35%, while V. minor causes a milder form of disease called alastrim and kills ~1% of its victims.[2][1] Long-term side-effects for survivors include the characteristic skin scars. Occasional side effects include blindness due to corneal ulcerations and infertility in male survivors.
Historical Perspective
Up until 1977, smallpox has been a very prevalent part of human history. The disease is estimated to be at least 16,000 years old and played a major role in the history of Europe, Asia, North America, Africa, etc. The first clinical evidence of the diseases was found in an Egyptian mummy, Ramses V. Smallpox has also been used as a weapon throughout history. The most recent example was the weaponization of smallpox during World War II. After successful vaccination campaigns throughout the 19th and 20th centuries, the WHO certified the eradication of smallpox in 1979.[3] To this day, smallpox is the only human infectious disease to have been completely eradicated from nature.[4]
Eradication
The eradication of smallpox required a global effort. Every country was susceptible to the devastating disease. Eradicating this infection would take many years a significant sum of money, but with a worldwide commitment, it would be possible. Success was achieved in the 1970s and smallpox was officially eradicated.
Causes
Smallpox is caused by the variola virus that emerged in human populations thousands of years ago. Except for laboratory stockpiles, the variola virus has been eliminated.
Differentiating Smallpox from other Diseases
In the past, chickenpox was regularly mistaken for smallpox. Pustular scarring that can be seen in the face is a common symptom of both infections. Many times herpes zoster and erythema multiforme produce a vesicular rash and fever that has been confused with smallpox.
Epidemiology and Demographics
Smallpox killed an estimated 60 million Europeans, including five reigning European monarchs, in the 18th century alone. Up to 30% of those infected, including 80% of the children under 5 years of age, died from the disease, and one third of the survivors became blind.[5][6]
Smallpox was responsible for an estimated 300–500 million deaths in the 20th century. As recently as 1967, the World Health Organization (WHO) estimated that 15 million people contracted the disease and that two million died in that year.[3]
Risk Factors
Smallpox is a contagious disease and contact with an infected individual could cause smallpox infection. It is also possible to acquire the infection through an airborne release of the smallpox virus.
Treatment
Primary Prevention
The smallpox vaccine helps the body develop immunity to smallpox. The vaccine is made from a virus called vaccinia which is a “pox”-type virus related to smallpox. The smallpox vaccine contains the “live” vaccinia virus—not dead virus like many other vaccines. For that reason, the vaccination site must be cared for carefully to prevent the virus from spreading. Also, the vaccine can have side effects. The vaccine does not contain the smallpox virus and cannot give you smallpox.
Currently, the United States has a big enough stockpile of smallpox vaccine to vaccinate everyone in the United States in the event of a smallpox emergency.
Outbreak Prevention
CDC has a detailed plan to protect Americans against the use of smallpox as a biological weapon. This plan includes the creation and use of special teams of health care and public health workers. If a smallpox case is found, these teams will take steps immediately to control the spread of the disease. Smallpox was wiped out through specific public health actions, including vaccination, and these actions will be used again.
Cost-effectiveness of Therapy
Smallpox has been successfully eradicated since the 1970s , but there was a great deal of money spent in the eradication process. Through donor governments, as well as other sources, it has been estimated that there was $300 million spent on eliminating smallpox.
References
- ↑ 1.0 1.1 Ryan KJ, Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed. ed.). McGraw Hill. pp. 525&ndash, 8. ISBN 0838585299.
- ↑ Behbehani AM (1983). "The smallpox story: life and death of an old disease". Microbiol Rev. 47 (4): 455–509. PMID 6319980.
- ↑ 3.0 3.1 "Smallpox". WHO Factsheet. Retrieved 2007-09-22.
- ↑ De Cock KM (2001). "(Book Review) The Eradication of Smallpox: Edward Jenner and The First and Only Eradication of a Human Infectious Disease". Nature Medicine. 7: 15&ndash, 6.
- ↑ Barquet N, Domingo P (1997). "Smallpox: the triumph over the most terrible of the ministers of death". Ann. Intern. Med. 127 (8 Pt 1): 635–42. PMID 9341063.
- ↑ Edward Jenner and the history of smallpox and vaccination