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Smallpox: the story on HearLore | HearLore
Smallpox
The earliest credible clinical evidence of smallpox dates to around 1500 BCE, found in the mummified remains of the Egyptian pharaoh Ramses V, who died in 1145 BCE. This ancient disease, caused by the Variola virus, was not merely a medical nuisance but a relentless force that shaped the course of human civilization. For millennia, it stood as one of the most feared and deadly pathogens known to humanity, claiming an estimated 300 million lives in the 20th century alone and killing up to 500 million people in the last 100 years of its existence. The disease was so pervasive that it became a predominant cause of morbidity and mortality throughout much of the world by the 16th century. In 18th-century Europe, smallpox was a leading cause of death, killing an estimated 400,000 people each year, and it is estimated that one-third of all cases of blindness were due to the disease. The historical impact was so profound that six European monarchs, including Louis XV of France who died in 1774, fell victim to the virus. The disease was introduced into the Americas during the Columbian exchange, resulting in large swathes of Native Americans dying, with case fatality rates during outbreaks in these populations reaching as high as 90 percent. This demographic collapse was an important factor in the Spanish achieving conquest of the Aztecs and the Incas, fundamentally altering the geopolitical landscape of the New World.
The Anatomy of a Killer
The initial symptoms of smallpox were deceptively similar to other viral diseases that are still extant, such as influenza and the common cold, featuring a fever of at least 102 degrees Fahrenheit, muscle pain, malaise, headache, and fatigue. As the digestive tract was commonly involved, nausea, vomiting, and backache often occurred during the early prodromal stage, which usually lasted 2 to 4 days. By days 12 to 15, the first visible lesions, small reddish spots called enanthem, appeared on the mucous membranes of the mouth, tongue, palate, and throat, and the temperature fell to near-normal. These lesions rapidly enlarged and ruptured, releasing large amounts of virus into the saliva. The virus then attacked skin cells, causing the characteristic pimples, or macules, associated with the disease. A rash developed on the skin 24 to 48 hours after lesions on the mucous membranes appeared, typically first on the forehead, then rapidly spreading to the whole face, proximal portions of extremities, the trunk, and lastly to distal portions of extremities. The process took no more than 24 to 36 hours, after which no new lesions appeared. Over a number of days, the skin rash turned into the characteristic fluid-filled blisters with a dent in the center. The bumps then scabbed over and fell off, leaving scars. The disease was transmitted from one person to another primarily through prolonged face-to-face contact with an infected person or rarely via contaminated objects. The risk of death was about 30 percent, with higher rates among babies, and often, those who survived had extensive scarring of their skin, and some were left blind.
Common questions
When was smallpox first documented in human history?
The earliest credible clinical evidence of smallpox dates to around 1500 BCE, found in the mummified remains of the Egyptian pharaoh Ramses V, who died in 1145 BCE.
What were the symptoms of smallpox infection?
Initial symptoms included a fever of at least 102 degrees Fahrenheit, muscle pain, malaise, headache, and fatigue, followed by nausea, vomiting, and backache during the early prodromal stage. Visible lesions appeared on the mucous membranes of the mouth and throat by days 12 to 15, followed by a rash on the skin that developed into fluid-filled blisters before scabbing over.
How many people died from smallpox in the 20th century?
Smallpox claimed an estimated 300 million lives in the 20th century alone and killed up to 500 million people in the last 100 years of its existence. In 18th-century Europe, the disease killed an estimated 400,000 people each year.
When was smallpox officially declared eradicated?
The global eradication of smallpox was certified by a commission of eminent scientists on the 9th of December 1979 and subsequently endorsed by the World Health Assembly on the 8th of May 1980. This achievement made smallpox the only human disease to have been eradicated.
Who was the last person to die from naturally occurring smallpox?
The last naturally occurring case of indigenous smallpox, Variola minor, was diagnosed in Ali Maow Maalin, a hospital cook in Merca, Somalia, on the 26th of October 1977. The last naturally occurring case of the more deadly Variola major had been detected in October 1975 in a three-year-old Bangladeshi girl named Rahima Banu.
When were the last known smallpox virus samples destroyed?
The CDC destroyed the virus under WHO observation on the 24th of February 2015 after samples were discovered in an FDA laboratory at the National Institutes of Health location in Bethesda, Maryland. These samples were dated 1954 and had been found in a cold storage room on the 1st of July 2014.
There are two forms of the smallpox virus, Variola major and Variola minor, which presented with vastly different outcomes for the infected. Variola major was the severe and more common form, with a more extensive rash and higher fever, carrying a fatality rate of around 30 percent. In contrast, Variola minor was a less common presentation, causing less severe disease, typically discrete smallpox, with historical death rates of 1 percent or less. In addition, there were two very rare and fulminating types of smallpox, the malignant and hemorrhagic forms, which were usually fatal. Malignant smallpox, also called flat smallpox, accounted for 5 to 10 percent of cases, and most were children. In this form, the lesions remained almost flush with the skin at the time when raised vesicles would have formed in the ordinary type. The rash on the mucous membranes was extensive, and skin lesions matured slowly, were typically confluent or semi-confluent, and by the seventh or eighth day, they were flat and appeared to be buried in the skin. Malignant smallpox was nearly always fatal, and death usually occurred between the 8th and 12th day of illness. Hemorrhagic smallpox is a severe form accompanied by extensive bleeding into the skin, mucous membranes, gastrointestinal tract, and viscera. This form develops in approximately 2 percent of infections and occurs mostly in adults. Pustules do not typically form in hemorrhagic smallpox. Instead, bleeding occurs under the skin, making it look charred and black, hence this form of the disease is also referred to as variola nigra or black pox. While bleeding may occur in mild cases and not affect outcomes, hemorrhagic smallpox is typically fatal, with the case fatality rate for early hemorrhagic smallpox approaching 100 percent.
The Science of Survival
The earliest procedure used to prevent smallpox was inoculation with variola minor virus, a method later known as variolation after the introduction of smallpox vaccine to avoid possible confusion, which likely occurred in India, Africa, and China well before the practice arrived in Europe. Accounts of inoculation against smallpox in China can be found as early as the late 10th century, and the procedure was widely practiced by the 16th century, during the Ming dynasty. If successful, inoculation produced lasting immunity to smallpox. Because the person was infected with variola virus, a severe infection could result, and the person could transmit smallpox to others. Variolation had a 0.5 to 2 percent mortality rate, considerably less than the 20 to 30 percent mortality rate of smallpox. In 1796, Edward Jenner, a doctor in Berkeley, Gloucestershire, rural England, discovered that immunity to smallpox could be produced by inoculating a person with material from a cowpox lesion. Cowpox is a poxvirus in the same family as variola. Jenner called the material used for inoculation vaccine from the root word vacca, which is Latin for cow. The procedure was much safer than variolation and did not involve a risk of smallpox transmission. Vaccination to prevent smallpox was soon practiced all over the world. During the 19th century, the cowpox virus used for smallpox vaccination was replaced by the vaccinia virus. The current formulation of the smallpox vaccine is a live virus preparation of the infectious vaccinia virus. The vaccine is given using a bifurcated needle that is dipped into the vaccine solution. The needle is used to prick the skin, usually the upper arm, several times in a few seconds, a process that is painless and comfortable for even children. If successful vaccination via the bifurcated needle occurs, a red and itchy bump develops at the vaccine site in three or four days. In the first week, the bump becomes a large blister, called a Jennerian vesicle, which fills with pus and begins to drain. During the second week, the blister begins to dry up, and a scab forms. The scab falls off in the third week, leaving a small scar. Historically, the vaccine has been effective in preventing smallpox infection in 95 percent of those vaccinated.
The Global Eradication Campaign
In 1967, the World Health Organization intensified efforts to eliminate the disease, setting a goal of ten years for the elimination of smallpox, which was referred to as Target Zero. This goal was missed by only nine months. The key to this strategy was the monitoring of cases in a community, known as surveillance, and containment. The initial problem the WHO team faced was inadequate reporting of smallpox cases, as many cases did not come to the attention of the authorities. The fact that humans are the only reservoir for smallpox infection, the virus only infected humans and not other animals, and that carriers did not exist played a significant role in the eradication of the disease. The WHO established a network of consultants who assisted countries in setting up surveillance and containment activities. Early on, donations of vaccine were provided primarily by the Soviet Union and the United States, but by 1973, more than 80 percent of all vaccines were produced in developing countries. The Soviet Union provided one and a half billion doses between 1958 and 1979, as well as the medical staff. The last naturally occurring case of indigenous smallpox, Variola minor, was diagnosed in Ali Maow Maalin, a hospital cook in Merca, Somalia, on the 26th of October 1977. The last naturally occurring case of the more deadly Variola major had been detected in October 1975 in a three-year-old Bangladeshi girl, Rahima Banu. The global eradication of smallpox was certified, based on intense verification activities, by a commission of eminent scientists on the 9th of December 1979 and subsequently endorsed by the World Health Assembly on the 8th of May 1980, making smallpox the only human disease to have been eradicated.
The Final Cases and the Lasting Shadow
The final known fatal case of smallpox occurred in 1978 in a laboratory in the United Kingdom. A medical photographer, Janet Parker, contracted the disease at the University of Birmingham Medical School and died on the 11th of September 1978. Although it has remained unclear how Parker became infected, the source of the infection was established to be the variola virus grown for research purposes at the Medical School laboratory. All known stocks of smallpox worldwide were subsequently destroyed or transferred to two WHO-designated reference laboratories with BSL-4 facilities, the United States Centers for Disease Control and Prevention and the Soviet Union State Research Center of Virology and Biotechnology VECTOR. WHO first recommended destruction of the virus in 1986 and later set the date of destruction to be the 30th of December 1993. This was postponed to the 30th of June 1999. Due to resistance from the U.S. and Russia, in 2002 the World Health Assembly agreed to permit the temporary retention of the virus stocks for specific research purposes. The United States and Russia retain samples of variola virus in laboratories, which has sparked debates over safety. On the 1st of July 2014, six sealed glass vials of smallpox dated 1954, along with sample vials of other pathogens, were discovered in a cold storage room in an FDA laboratory at the National Institutes of Health location in Bethesda, Maryland. The smallpox vials were subsequently transferred to the custody of the CDC in Atlanta, where virus taken from at least two vials proved viable in culture. After studies were conducted, the CDC destroyed the virus under WHO observation on the 24th of February 2015. The eradication of smallpox has been called one of the noblest and best things that we have ever done, as a species, yet the existence of these remaining stocks continues to fuel controversy regarding the potential for biological warfare and the necessity of maintaining research capabilities.