Welcome to the last installation of our exploration of diseases! While I debated some on what illness to focus on for this final post, I decided to go back to this blog’s roots. We started this journey by looking at rinderpest, an animal-only disease that is one of only two to have been fully eradicated. Now, we’ll be looking at its foil, one of the most historically relevant infectious agents of all time and the only human disease to be eradicated: smallpox.

Caused by Variola major (and occasionally Variola minor), the disease had a 30% mortality rate and could result in permanent scarring and blindness. Symptoms often emerged around two weeks post-exposure to an infected individual or contaminated surfaces, and they involved fever, vomiting, a characteristic rash, and eventual scabbing. 

With the first cases possibly occurring as far back 12,000 years ago, smallpox caused problems throughout many phases of human civilization. Rashes found on Egyptian mummies are typically referenced as supporting the claim that the virus has been around for at least 3,000 years, though the relatively recent finding of DNA from a 17th century mummy uncovered in Lithuania suggest that the disease may not be as old as previously theorized. Regardless of the exact date of emergence, the disease has had a massive impact, even bringing some cultures to establish smallpox deities.

Early treatments for the disease included the classics, like bloodletting and herbal remedies. Variolation was another method that emerged in Asia and Africa before spreading to Europe. The technique involved inserting pus and powdered scabs into the skin and nose of healthy individuals. Some of these procedures resulted in patients’ deaths, though this was at a lesser degree than the disease itself.

Edward Jenner’s invention of the smallpox vaccine in 1796 would give an even better form of protection against the virus. By inoculating patients with pus from the sores of milkmaids infected with smallpox, he was able to prevent the disease. The process rarely caused a rash, and vaccinated individuals couldn’t spread the virus. This was a revolutionary development, both in addressing smallpox and diseases as a whole, as it was the first vaccine ever invented.

The vaccine would gradually be accepted by the public. Over time, it would be fine-tuned to be more heat-stable, and the mode of vaccination would change slightly with the invention of the bifurcated needle. However, the general premise stayed constant. Thanks to the vaccine and its promotion, the United States would have its last outbreak in 1949 (though the disease persisted in other nations).

In 1967, the WHO would launch a campaign to eradicate smallpox. The pathogen was selected as a candidate for eradication thanks to several of its characteristics, including the availability of an effective vaccine and the lack of animal reservoirs that could serve as hidden sources of the virus. The initial efforts involved mass-vaccination, which gradually phased into a more targeted approach in which healthcare workers tracked cases and vaccinated those exposed to the infected individual. This would end in success, with the last case of naturally-occurring infection happening in Somalia in 1977. Though there would be a small outbreak in 1978 attributable to a lab accident in England, the disease had been eliminated from the wild, and it was officially declared eradicated in 1980. 

Nowadays, the only remaining smallpox that is known to exist can be found in labs in Atlanta, Georgia, and in Russia. Routine vaccination is no longer performed in the United States, though select groups (such as military personnel) are still immunized as a protective measure in the event that the agent were to be used in bioterrorism. In that horrible scenario, the United States does have a stockpile of vaccines that could be used to protect civilians. However, it should hopefully never need to be used. 

With that being said, for the last time: wash your hands, stay healthy, and thank you for reading!

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References

Bradford, Alina. “Smallpox: The World’s First Eradicated Disease.” Live Science, Future US, 23 Apr. 2019, www.livescience.com/65304-smallpox.html. Accessed 12 Apr. 2022.

Greenspan, Jesse. “The Rise and Fall of Smallpox.” History, A&E Television Networks, 15 May 2020, www.history.com/news/the-rise-and-fall-of-smallpox. Accessed 12 Apr. 2022.

“Smallpox.” American Museum of Natural History, www.amnh.org/explore/science-topics/disease-eradication/countdown-to-zero/smallpox. Accessed 12 Apr. 2022.

“Smallpox.” Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, 12 July 2017, www.cdc.gov/smallpox/index.html. Accessed 12 Apr. 2022.