Overview
This lecture traces the history of smallpox, from its deadly origins and global spread to humanity's eventual triumph over the disease through vaccination.
Origins and Impact of Smallpox
- Smallpox originated around 10,000 years ago in northeastern Africa and spread worldwide.
- The virus attacks skin cells, bone marrow, spleen, and lymph nodes, leading to fever, vomiting, and rashes.
- About 30% of infected people died in the second week; survivors bore lifelong scars.
- The first epidemic occurred in 1350 B.C. during the Egypt-Hittite war, spreading through war and trade.
- Smallpox killed billions, including 300–500 million in the 20th century alone.
Early Attempts at Prevention: Variolation
- In 1022 A.D., a Buddhist nun in China developed variolation, blowing powdered smallpox scabs into nostrils.
- Observations showed survivors of smallpox were immune to reinfection.
- By the 1700s, variolation involved placing pus from sores into scratches on healthy people’s arms.
- Variolation reduced infection risk but still caused death in up to 3% of those treated.
Jenner and the Invention of Vaccination
- Edward Jenner noticed dairy maids infected with cowpox did not get smallpox.
- Cowpox is a related but less dangerous virus from the same family as smallpox.
- In 1796, Jenner inoculated James Phipps with cowpox from Sarah Nelmes, making him immune to smallpox.
- Jenner's vaccination method used cowpox virus, which was safer than variolation.
- Over time, vaccination replaced variolation and was officially accepted in England by 1840.
Eradication of Smallpox
- Mass vaccination campaigns in the 19th and 20th centuries led to smallpox eradication.
- The World Health Organization declared smallpox eradicated in 1979.
- Key contributors included Edward Jenner, the Buddhist nun, Sarah Nelmes, and James Phipps.
Key Terms & Definitions
- Smallpox — a deadly viral disease causing fever, rash, and high mortality.
- Variolation — early prevention method using smallpox material to induce immunity.
- Vaccination — using cowpox virus to safely induce immunity to smallpox.
- Immunology — the study of the immune system and immunity.
Action Items / Next Steps
- Review key differences between variolation and vaccination.
- Prepare for questions on historical milestones in smallpox prevention.