History of Smallpox

Origin of Smallpox

The origin of smallpox is unknown. Smallpox is thought to date back to the Egyptian Empire around the 3^rd century BCE (Before Common Era), based on a smallpox-like rash found on three mummies. The earliest written description of a disease that clearly resembles smallpox appeared in China in the 4^th century CE (Common Era). Early written descriptions also appeared in India in the 7^th century and in Asia Minor in the 10^th century.

Spread of Smallpox

The global spread of smallpox can be traced to the growth and spread of civilizations, exploration, and expanding trade routes over the centuries.

Historical Highlights:

• 6^th Century – Increased trade with China and Korea introduces smallpox into Japan.
• 7^th Century – Arab expansion spreads smallpox into northern Africa, Spain, and Portugal.
• 11^th Century – Crusades further spread smallpox in Europe.
• 15^th Century – Portuguese occupation introduces smallpox into part of western Africa.
• 16^th Century – European colonization and the African slave trade import smallpox into the Caribbean and Central and South America.
• 17^th Century – European colonization imports smallpox into North America.
• 18^th Century – Exploration by Great Britain introduces smallpox into Australia.

Early Control Efforts

Smallpox was a devastating disease. On average, 3 out of every 10 people who got it died. Those who survived were usually left with scars, which were sometimes severe.

One of the first methods for controlling the spread of smallpox was the use of variolation. Named after the virus that causes smallpox (variola virus), variolation is the process by which material from smallpox sores (pustules) was given to people who had never had smallpox. This was done either by scratching the material into the arm or inhaling it through the nose. With both types of variolation, people usually went on to develop the symptoms associated with smallpox, such as fever and a rash. However, fewer people died from variolation than if they had acquired smallpox naturally.

The basis for vaccination began in 1796 when an English doctor named Edward Jenner observed that milkmaids who had gotten cowpox did not show any symptoms of smallpox after variolation. The first experiment to test this theory involved milkmaid Sarah Nelmes and James Phipps, the 9 year-old son of Jenner’s gardener. Dr. Jenner took material from a cowpox sore on Nelmes’ hand and inoculated it into Phipps’ arm. Months later, Jenner exposed Phipps a number of times to variola virus, but Phipps never developed smallpox. More experiments followed, and, in 1801, Jenner published his treatise “On the Origin of the Vaccine Inoculation,” in which he summarized his discoveries and expressed hope that “the annihilation of the smallpox, the most dreadful scourge of the human species, must be the final result of this practice.”

Vaccination became widely accepted and gradually replaced the practice of variolation. At some point in the 1800s (the precise time remains unclear), the virus used to make the smallpox vaccine changed from cowpox to vaccinia virus.

Global Smallpox Eradication Program

In 1959, the World Health Organization (WHO) initiated a plan to rid the world of smallpox. Unfortunately, this global eradication campaign suffered from lack of funds, personnel, and commitment from countries, as well as a shortage of vaccine donations. Despite their best efforts, smallpox was still widespread in 1966, causing regular outbreaks in multiple countries across South America, Africa, and Asia.

The Intensified Eradication Program began in 1967 with a promise of renewed efforts. This time, laboratories in many countries where smallpox occurred regularly (endemic countries) were able to produce more, higher quality freeze-dried vaccine. A number of other factors also played an important role in the success of the intensified efforts, including the development of the bifurcated needle, establishment of a surveillance system to detect and investigate cases, and mass vaccination campaigns, to name a few.

By the time the Intensified Eradication Program began in 1967, smallpox had already been eliminated in North America (1952) and Europe (1953), leaving South America, Asia, and Africa (smallpox was never widespread in Australia). The Program made steady progress toward ridding the world of this disease, and by 1971 smallpox was eradicated from South America, followed by Asia (1975), and finally Africa (1977).

Last Cases of Smallpox

In late 1975, Rahima Banu, a three-year-old girl from Bangladesh, was the last person in the world to have naturally acquired variola major and the last person in Asia to have active smallpox. She was isolated at home with house guards posted 24 hours a day until she was no longer infectious. A house-to-house vaccination campaign within a 1.5 mile radius of her home began immediately, and every house, public meeting area, school, and healer within 5 miles was visited by a member of the Smallpox Eradication Program team to ensure the illness did not spread. A reward was also offered to anyone for reporting a smallpox case.

Ali Maow Maalin was the last person to have naturally acquired smallpox caused by variola minor. Maalin was a hospital cook in Merca, Somalia. On October 12, 1977, he accompanied two smallpox patients in a vehicle from the hospital to the local smallpox office. On October 22, he developed a fever. At first he was diagnosed with malaria, and then chickenpox. He was correctly diagnosed with smallpox by the smallpox eradication staff on October 30. Maalin was isolated and made a full recovery. Maalin died of malaria on July 22, 2013 while working in the polio eradication campaign.

Janet Parker was the last person to die of smallpox. It was 1978, and Parker was a medical photographer at the Birmingham University Medical School in England and worked one floor above the Medical Microbiology Department where smallpox research was being conducted. She became ill on August 11 and developed a rash on August 15 but was not diagnosed with smallpox until 9 days later. She died on September 11, 1978. Her mother, who was providing care for her, developed smallpox on September 7, despite having been vaccinated on August 24. An investigation performed afterward suggested that Janet Parker had been infected either via an airborne route through the medical school building’s duct system or by direct contact while visiting the microbiology corridor one floor above.

World Free of Smallpox

Almost two centuries after Jenner published his hope that vaccination could annihilate smallpox, on May 8, 1980, the 33^rd World Health Assembly officially declared the world free of this disease. Eradication of smallpox is considered the biggest achievement in international public health.

Stocks of Variola Virus

Following the eradication of smallpox, scientists and public health officials determined there was still a need to perform research using the variola virus. They agreed to reduce the number of laboratories holding stocks of variola virus to only four locations. In 1981, the four countries that either served as a WHO collaborating center or were actively working with variola virus were the United States, England, Russia, and South Africa. By 1984, England and South Africa had either destroyed their stocks or transferred them to other approved labs. There are now only two locations where variola virus is officially stored and handled under WHO supervision: the Centers for Disease Control and Prevention in Atlanta, Georgia, and the State Research Center of Virology and Biotechnology (VECTOR Institute) in Koltsovo, Russia.