The diseases caused by poxviruses, particularly smallpox have long been feared as agents of terrible illness. Even during the Egyptian empire, smallpox was known and it is believed that the Pharoah Ramses V died of the disease in 1157 B.C. In India, smallpox was already endemic two thousand years agoand quickly spread to China,Japan, and Northern Africa. It is believed that slave traders introduced smallpox in sub-Saharan Africa. In the nations in which smallpox was endemic, it became a part of life, with evidence of its impact in various cultural practices still intact although smallpox has been eradicated worldwide for some time. To the right,the Priestess Omolajaya Oloroke of Nigeria presides over the Obulawaye Shrine of Obulawaye, god of smallpox - formerly the most dreaded disease in Yorubaland.
The mural decorations behind her suggest the marks of smallpox when Obulawaye strikes. The disease reached Europe in 710 A.D., and its spread to the rest of the world is thought to have been facilitated by European voyages of discovery and colonization. In 1520, Hernando Cortez led the conquest that toppled the Aztec empire. Cortez' success was due to the work of smallpox which may killed 3.5 million Aztecs died in only 2 years. In the 10th century, smallpox scab material or pustule fluid was inoculated into the skin in what was called "variolation." In some cases, the procedure was effective in preventing severe disease. Edward Jenner in 1796, innoculated individuals with a close relative of the smallpox virus, the cowpox virus. He showed that those given the innoculation were completely resistant to smallpox. The use of a smallpox "vaccine" quickly spread, and later the live attenuated vaccina virus vaccine predominated in use. Although the origin of this virus strain has not been completely deciphered, the results of its use were phenomenal. By the 1950's smallpox had been largely eradicated from the industrialized countries in which it had been endemic. In 1967, the Smallpox Eradication Unit was established by the World Health Assembly at the World Health Organization center. Innovative means of storage as well as the effective distribuation of vaccines led to mass vaccination worldwide, which was strongly aided by surveillance, containment. Interestingly, the bifurcated needle is also credited with aiding in the eradication process. Slowly, the progress of eradication was becoming clear. In 1979, the World Health Organiation declared the world free of endemic smallpox. Currently, vaccination is only recommended for laboratory workers who work directly with cultures or animals infected with vaccinia, its recombinants, or other human infecting orthopoxviruses.

Click here to see progression of smallpox eradication.

*Special thanks to the American Museum of Natural History and Phyllis Galembo for the use of the photograph.

Molluscum Contagiosum

Molluscum contagiosum is a human disease that has been largely regarded as a trivial infection. However, since 1980 with the surgence of HIV disease, many people have become immunocompromised, and thus are often the victims of such opportunistic infections.


Cowpox has been known in Europe for centuries as a disease of cows. The disease, appearing as ulcers, can also cause lesions on the hands of milkers. Jenner made the observation that milk maids, though they developed cowpox lesions, were not susceptible to smallpox infection. Thus, the first smallpox vaccination was developed.

Human Monkeypox

The incidence of human monkey pox was discovered in West and Central Africa in the early 1970's. Smallpox had already been eradicated from these regions, but the signs and symptoms were very similar.The human disease of monkeypox has been cosidered a rare zoonosis, and though vaccinia can prevent the development of disease, it is so rare vaccination is believed unnecessary.

Yabapox and Tanapox

In 1957 and 1962, an epidemic of people of the flood plain of the Tana River in Kenya occurred that brought attention to the acute illness that produced skin lesions. This disease, now known as Tanapox is endemic to the region and was the disease later reported in monkeys in US centers in 1966 by which handlers were infected. Yabapox was observed in tumors that ocurred in rhesus monkeys in Nigeria. Though it is believed to infect human beings, none has been found in the field of Africa.


1157 B.C.
Pharoah Ramses V dies of smallpox

700 A.D.

Smallpox endemic in India, spread to China, Japan, Europe, and north Africa

Smallpox introduced to the Caribbean by the African slave trade

Millions of Aztec people die in smallpox epidemic

Jenner shows persons inoculated with cowpox virus are resistant to smallpox

Vaccinia virus used in vaccinations against variola 1950
Most industrialized contries have eliminated endemic smallpox

Tanapox epidemic in Kenya

World Health Assembly accepts the global eradication concept
Monkeypox virus discovered in laboratory primates in Copenhagen

Tanapox epidemic in Kenya

Smallpox Eradication Unit established at WHO

Surveillance of monkeypox infections by WHO

Global eradication of smallpox achieved

World officially declared free of smallpox

Molluscum contagiosum associated with immunocompromised patients

Important Researchers

Edward Jenner: In 1796, he showed that people inoculated with pox virus were resistant to smallpox. Though Jenner's "vaccine" was later replaced with vaccinia virus inoculation, he was instrumental in decreasing the incidence of smallpox in many countries.

Leslie Collier: Eradication of infectious diseases is often difficult because nations vary not only in political, economic, and cultural backgrounds, but in infrastructure. Many developing countries lack the transportation systems that are necessary for the delivery of supplies to rural regions of the nation. Therefore, Collier's development of the freeze-dried vaccine was vital in distributing the smallpox vaccine to even the most rural regions of the world. Thus, he made a tremendous contribution leading to the final worldwide eradication of smallpox.

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