Smallpox

Smallpox was an infectious disease caused by Variola virus. It was a very serious illness that spread easily from person to person, usually through close contact or sometimes through contaminated objects. People with smallpox would first feel very sick with fever and sometimes throw up. Then, they would get sores inside their mouths and a rash on their skin that turned into fluid-filled blisters. These blisters would dry up and fall off, often leaving scars, and some people lost their sight.

The disease could be very dangerous, and about 30% of people who got it died, especially babies. Even those who survived often had bad scars or went blind. Smallpox has been around for thousands of years, with evidence found in ancient Egyptian mummies. It caused many deaths throughout history, including among many people in the New World after it was brought there. In Europe, hundreds of thousands of people died each year during the 1700s alone.

The good news is that through hard work and science, smallpox was eliminated, or completely gotten rid of, worldwide. This happened because of a special vaccine created by a man named Edward Jenner in 1796. By 1980, the World Health Organization announced that smallpox was gone forever, making it the first disease in history to be completely wiped out. Today, only a few samples of the virus are kept safe in special laboratories.

Classification

There were two main forms of smallpox. Variola major was the more serious and common type, causing a widespread rash and higher fever. Variola minor was less common and caused milder disease, with very low rates of serious outcomes.

Most cases of smallpox were of the ordinary type. In this form, the skin changes would start as flat spots that become raised bumps. These bumps would then fill with fluid, becoming blisters. Over time, the blisters would turn into pus-filled spots that crust over and fall off, often leaving marks on the skin. The rash was usually most noticeable on the face and the ends of the arms and legs.

Sometimes, the blisters would merge together, creating a more serious form of the disease. Another less serious form often occurred in people who had been protected against smallpox before, with fewer and less severe skin changes. There were also very rare and severe types of smallpox that were usually fatal, including one where the skin would bleed and turn dark.

Signs and symptoms

Smallpox started with symptoms like those of other common illnesses, such as influenza and the common cold. People would feel very hot, tired, have headaches, and muscle aches. Sometimes, they also felt sick to their stomachs and threw up.

Later, small red spots would appear inside the mouth and on the skin. These spots would grow and change, creating the rash that is well-known from this disease. The spots usually first showed up on the face and then spread to the rest of the body.

Cause

Smallpox was caused by infection with the Variola virus, which belongs to the family Poxviridae, subfamily Chordopoxvirinae, and genus Orthopoxvirus.

The disease most likely developed from a virus found in African rodents between 68,000 and 16,000 years ago. There are two main types of the virus: one more severe form and a milder form. The milder form was found in places like the United States and Europe in the early 1900s and helped reduce death rates from smallpox. The last known case of smallpox was in 1977, and the disease was officially declared erased from the world in 1980.

The Variola virus is large and shaped like a brick. It has a linear double stranded DNA genome and can infect only humans. The virus reproduces inside the cell’s cytoplasm and can spread through close contact with infected people.

Mechanism

When someone breathed in the variola virus, it entered the lining of their mouth, throat, and breathing tubes. The virus then moved to nearby lymph nodes and started to grow. At first, the virus moved between cells, but after about 12 days, many infected cells broke apart. This caused the virus to spread through the blood, a stage called viremia. The virus then multiplied again in the spleen, bone marrow, and lymph nodes.

Diagnosis

Before scientists had special tests, doctors could tell if someone had smallpox just by looking at the hard bumps on the skin. Now, there are better ways to check, like looking at tiny parts of the virus under special microscopes.

Scientists can also grow the virus in a part of a chicken egg to see if it causes certain changes. There are also quick tests that can show if the virus is present.

Sometimes, another illness called chickenpox can look like smallpox. But there are ways to tell them apart. For example, chickenpox does not usually affect the palms of the hands or the soles of the feet, and the bumps in chickenpox are often different sizes, while smallpox bumps are usually all about the same size.

Prevention

One of the first ways people found to fight smallpox was through a method called inoculation. This meant giving a small amount of the virus to someone to help their body learn to fight it. This method started long ago in places like India, Africa, and China. Later, a better way was found by a doctor named Edward Jenner in 1796. He discovered that using a similar but safer virus from cows, called cowpox, could stop smallpox without making people sick. This new method was called vaccination.

Today, the smallpox vaccine uses a safe virus to help people’s bodies fight the disease. The vaccine is given with a special needle that gently pokes the skin a few times. After getting the vaccine, a small bump forms and turns into a blister that later becomes a scab. This shows the body is building protection. The vaccine works well and helps protect against other similar viruses too.

Treatment

Getting a smallpox vaccination within three days of exposure can stop or make the illness much milder for most people. If the vaccination is given four to seven days after exposure, it might still help a little or make the disease less severe. Besides vaccination, treatment focuses on helping the body, like caring for wounds, controlling infections, giving fluids, and sometimes using a ventilator to help with breathing.

There are medicines that can help treat smallpox. In 2018, a drug called tecovirimat was approved especially for this purpose. Another medicine, Brincidofovir, was approved in 2021 to treat smallpox caused by the variola virus.

Prognosis

Smallpox could be very serious, especially for young children. The lighter form of the disease, called variola minor, had a death rate of about 1%. The more severe form, variola major, had a much higher death rate of around 30%.

In the worst cases, death usually happened between 10 to 16 days after the illness began. The body’s reaction to the infection could become overwhelming, leading to serious problems. Some people developed breathing issues, brain problems, or severe skin damage. Many survivors were left with deep scars, especially on their faces.

History

Main article: History of smallpox

Disease emergence

See also: Native American disease and epidemics, History of smallpox in Mexico, and List of epidemics and pandemics

The earliest signs of smallpox appear in old medical writings from ancient India (as early as 1500 BCE) and China (1122 BCE). Researchers also studied a mummy from Egypt dating back to 1145 BCE. It is believed that traders from Egypt may have brought smallpox to India thousands of years ago. Smallpox likely reached China around the 1st century CE and then spread to Japan in the 6th century. In Japan, a big outbreak in the years 735–737 may have killed a large part of the population. Many cultures had gods or goddesses linked to smallpox, like the Yoruba god Sopona in West Africa and the Hindu goddess Shitala in India.

Some think smallpox may have started later, around 1588 CE, and that earlier cases were mistaken.

It is unclear when smallpox arrived in Europe and southwestern Asia. It is not mentioned in the Bible or in ancient Greek and Roman writings. Some believe the Plague of Athens—or a plague in Carthage in 396 BCE—might have been smallpox, but many experts doubt it.

The Antonine Plague in the Roman Empire (165–180 CE) might have been smallpox. By the Middle Ages, several outbreaks happened in Europe. Smallpox became common there after the Crusades increased travel and population movement. By the 16th century, it was widespread across Europe, often killing up to 30 percent of its victims.

Smallpox was not known in the Americas before European explorers arrived in the 15th century. It reached the Caribbean island of Hispaniola in 1507 and the mainland in 1520 with Spanish settlers. Native American populations had no immunity, so many died. This helped the Spanish conquer the Aztecs and Incas. Smallpox also caused big problems for Native Americans and settlers in North America and later reached Australia in 1789.

By the mid-18th century, smallpox was common worldwide except in places like Australia. In Europe, it killed hundreds of thousands each year. Up to 10 percent of Swedish infants died from it. Some places used a method called variolation to protect people, but vaccination in the late 19th century was more effective. By the mid-20th century, two types of smallpox—milder variola minor and more severe variola major—existed in Africa. Variola minor could spread more easily because people with it could move around.

Eradication

See also: Smallpox vaccine and Inoculation

The first known use of a method to protect against smallpox was in China, where people used powdered smallpox scabs. This could cause a mild case of the disease and make people immune. Reports of this reached Europe in the 1700s.

The English doctor Edward Jenner showed in 1796 that cowpox could protect against smallpox. This led to more efforts to eliminate smallpox. Countries like Russia, Britain, and the United States started vaccination programs.

By 1950, the Pan American Health Organization began efforts to eliminate smallpox in the Americas. In 1967, the World Health Organization started a global effort called Target Zero. The strategy involved finding and isolating cases and vaccinating people nearby, called "ring vaccination."

The last natural case of smallpox was found in Somalia in 1977. The world was officially declared free of smallpox in 1980.

Costs and benefits

The effort to eradicate smallpox involved many people and cost about US$300 million from 1967 to 1979. This has saved money since no vaccinations or treatments are needed now. Smallpox may have killed over 500 million people in the last century, making its eradication a major success.

Since eradication

The last known case of smallpox happened in the United Kingdom in 1978. All remaining samples of the virus are kept in two special labs. Scientists have discussed destroying these samples, but some believe they could help develop new medical treatments. In 2014, old vials of smallpox were found in a lab and safely destroyed. There have been concerns about the safety of these labs, especially after an accident in Russia in 2019.

Society and culture

Biological warfare

In 1763, a conflict called Pontiac's War began when a group of Native American leaders tried to resist British control over the Great Lakes area. During this time, a British leader named Henry Bouquet decided to use a dangerous method against the Native Americans. He gave blankets that had the smallpox disease to a group of Native American leaders outside Fort Pitt. This was done as a trick to spread the illness among them. There are also stories that similar tricks were used during the American Revolutionary War from 1775 to 1783.

During World War II, scientists from the United Kingdom, the United States, and Japan researched ways to use smallpox as a weapon. However, large-scale plans were never carried out because they thought the weapon would not be very effective due to the wide availability of a vaccine.

In 1947, a factory for making smallpox weapons was set up in the Soviet Union. In 1971, an outbreak of this weaponized smallpox happened during testing on an island in the Aral Sea. This led to several deaths, including children. Later, the Soviet government allowed inspections of some of its facilities, but the full extent of its activities remained unclear.

Notable cases

Many famous people throughout history had smallpox. For example, Sitting Bull, the Lakota Chief, and several emperors and rulers from different countries contracted the disease. Some, like the Kangxi Emperor of China, survived, while others, like Emperor Komei of Japan, did not.

In Europe, the disease sometimes changed who would become the next ruler. For instance, Louis XV of France became king partly because others ahead of him in line had died from smallpox or similar illnesses. He himself later died from the disease.

In the United States, Presidents George Washington, Andrew Jackson, and Abraham Lincoln all had smallpox but recovered. Washington got it during a visit to Barbados in 1751. Jackson got it after being captured by the British during the American Revolution, though his brother did not survive. Lincoln likely got it from his son Tad during his presidency in 1863.

Tradition and religion

Because smallpox was so dangerous, many cultures created gods or goddesses related to the disease. In China, the goddess T’ou-Shen Niang-Niang was worshipped. People tried to avoid angering her by using kind words for the disease and by setting up shrines in homes of those affected. If someone recovered, the shrines were removed and burned. If they did not, the shrines were destroyed.

In West Africa, the Yorùbá people believed in a deity named Sopona, who was linked to smallpox and other serious diseases. Sopona was both feared and seen as a healer. Worship of Sopona was tightly controlled, and it was believed that angering his priests could lead to the spread of the disease.

In India, the goddess Shitala was associated with smallpox. She was seen as both harmful and helpful. People worshipped her in shrines, hoping to avoid the disease or find healing. Some women placed cooling foods and water on their rooftops to try to protect themselves.

In places without specific smallpox gods, people often believed in demons causing the disease. Many thought these demons were afraid of the color red, leading to the practice of decorating patients and their rooms in red. This tradition continued until the 1930s, partly because studies showed red light could reduce scarring.