Smallpox is a highly contagious and deadly viral disease caused by the Variola virus. For centuries, it was one of the most feared illnesses, responsible for millions of deaths across the world. However, thanks to a global vaccination campaign, smallpox became the first disease ever eradicated by humans in 1980, as declared by the World Health Organization (WHO).
Causes of Smallpox
Smallpox is caused by the Variola virus, which belongs to the Orthopoxvirus genus. The disease spreads:
- Through respiratory droplets (coughing, sneezing)
- By direct contact with infected individuals
- Through contaminated objects, such as bedding or clothing
It was once a common disease with devastating effects but no longer poses a natural threat due to eradication efforts.
Symptoms of Smallpox
After an incubation period of 7 to 17 days, symptoms begin to appear. The disease progresses in stages:
- Initial Symptoms:
- High fever
- Fatigue
- Severe headache
- Back pain
- Vomiting (in some cases)
- Rash Stage:
- A red rash begins on the face and hands, then spreads
- Lesions evolve from macules to papules, vesicles, and then pustules
- Crusts form and eventually fall off
- Scarring:
- Survivors often suffer permanent scarring, especially on the face
Types of Smallpox
There were two clinical forms of smallpox:
- Variola major: Severe and most common form with a higher death rate (~30%)
- Variola minor: Milder version with a much lower fatality rate (~1%)
History and Eradication
- Ancient disease: Evidence of smallpox exists in Egyptian mummies and ancient texts.
- Edward Jenner (1796): Developed the first successful smallpox vaccine using cowpox.
- Global Vaccination Campaign: Led by the WHO from 1967 to 1977.
- Eradication: The last natural case was reported in Somalia in 1977. In 1980, the WHO declared smallpox eradicated globally.
Is There a Vaccine for Smallpox?
Yes. The smallpox vaccine is made from a virus called vaccinia, a poxvirus similar to smallpox. Though routine vaccination stopped after eradication, it is still used for:
- Laboratory workers handling poxviruses
- Military personnel
- Bioterrorism preparedness
Smallpox as a Bioterrorism Threat
Although smallpox is eradicated, concerns remain about its use as a biological weapon. Samples of the virus are retained under strict security in two laboratories (in the USA and Russia).
Key Facts About Smallpox
- Smallpox killed an estimated 300-500 million people in the 20th century.
- The vaccine was the key to its eradication.
- No treatment exists, but vaccination before or shortly after exposure can prevent or reduce severity.
Conclusion
Smallpox remains a powerful example of what global cooperation and science can achieve. Its eradication is a major milestone in public health history. While we no longer face the natural threat of smallpox, vigilance is crucial to prevent its misuse and maintain global safety.
