smallpox

Table of Contents

References & Edit History Quick Facts & Related Topics

Images

Edward Jenner inoculating his son with the smallpox vaccine, statue by Giulio Monteverde; in the Palazzo Bianco, Genoa, Italy.

For Students

smallpox summary

smallpox

Q: What causes smallpox?

Smallpox is caused by infection with variola major, a virus of the family Poxviridae . A less-virulent form of smallpox, called alastrim, is caused by a closely related virus known as variola minor. There are no natural animal carriers nor natural propagation of variola outside the human body.

Q: Does the smallpox virus still exist?

Smallpox was one of the first diseases to be controlled by a vaccine . In 1967 the World Health Organization (WHO) began a global vaccination program against smallpox, and in 1980 the disease was officially declared eradicated in the wild. Stocks of variola major were subsequently maintained in the United States and Russia.

Q: Could a person be reinfected with smallpox?

People who survived smallpox were permanently immune to a second infection, though they faced a lifetime of disfigurement and, in some cases, blindness.

Q: When did the last known case of smallpox occur?

The last endemic case of smallpox (actually an infection of variola minor) was recorded in Somalia in 1977. No cases were reported from 1977 to 1980 (when the disease was officially declared eradicated in the wild), except for two cases in England in 1978 whose source was in a laboratory.

Q: Is monkeypox related to smallpox?

Monkeypox is caused by the monkeypox virus, which is a member of Poxviridae , the same virus family that causes smallpox and cowpox .

disease

Also known as: variola major

Written and fact-checked by The Editors of Encyclopaedia Britannica

Last Updated: Mar 26, 2024 • Article History

Edward Jenner: smallpox vaccination

See all media

Category: Science & Tech

Also called:: variola major

Key People:: Zabdiel Boylston; Benjamin Waterhouse; Edward Jenner; Jan Ingenhousz

Related Topics:: biological weapon; smallpox vaccine; notifiable disease; variolation; variola major

See all related content →

What causes smallpox?

Does the smallpox virus still exist?

What was the mortality rate of smallpox?

Could a person be reinfected with smallpox?

When did the last known case of smallpox occur?

Is monkeypox related to smallpox?

smallpox, acute infectious disease that begins with a high fever, headache, and back pain and then proceeds to an eruption on the skin that leaves the face and limbs covered with cratered pockmarks, or pox. For centuries smallpox was one of the world’s most-dreaded plagues, killing as many as 30 percent of its victims, most of them children. Those who survived were permanently immune to a second infection, but they faced a lifetime of disfigurement and in some cases blindness. But smallpox was also one of the first diseases to be controlled by a vaccine, particularly following the great experiments ...(100 of 1824 words)

Access the full article

Help support true facts by becoming a member.