How fast did smallpox spread

Those who received this treatment contracted a mild form of the disease, developing a lifelong immunity. A key breakthrough came in when an experiment by English doctor Edward Jenner showed that inoculation using closely related cowpox could protect against smallpox. Jenner's discovery paved the way for later vaccination programs—especially crucial since there is no effective treatment for smallpox.

In , a year when some 10 million to 15 million people contracted smallpox, the World Health Organization launched a worldwide eradication campaign based on vaccination. Gradually, the disease was pushed back to the Horn of Africa, and the last known natural case occurred in Somalia in Despite being consigned to the history books, there's still a chance of smallpox coming back to haunt us—as a biological weapon.

Such fears escalated dramatically in the United States following the September 11, , terrorist attacks. While the risk of such a bioterror attack is considered very low, the U. All rights reserved. Smallpox Inspections A young Native American boy in Yukon Territory is checked for smallpox and vaccinated against the disease in this circa photograph. Early Victims Smallpox is thought to have originated in India or Egypt at least 3, years ago.

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Animals Wild Cities Morocco has 3 million stray dogs. Meet the people trying to help. A second vaccine, a modified vaccinia Ankara vaccine Jynneos , has been found to be safe, and it can be used in people who aren't able to take ACAM, who have weakened immune systems or who have skin disorders.

Immunity or partial immunity after a smallpox vaccine may last up to 10 years, and 20 years with revaccination. If an outbreak ever occurred, people who were vaccinated as children would still likely receive a new vaccination after direct exposure to someone with the virus.

Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. This content does not have an English version. This content does not have an Arabic version. Overview Smallpox is a contagious, disfiguring and often deadly disease that has affected humans for thousands of years.

Smallpox Open pop-up dialog box Close. Smallpox These are smallpox lesions on the skin of the trunk. Request an Appointment at Mayo Clinic.

Share on: Facebook Twitter. Show references Friedman HM, et al. The epidemiology, pathogenesis and clinical manifestations of smallpox. Accessed Feb. Smallpox vaccine: Drug information. Smallpox vaccine: Patient drug information.

Hall JB, et al. Biological warfare. In: Principles of Critical Care. However, by , smallpox was effectively eliminated as a public health concern, thanks to a major campaign conducted by the World Health Organization.

The last known case - anywhere in the world - was reported in the late s. Since no animals other than humans are known to carry or transmit smallpox, the risk of getting the illness had effectively been reduced to zero.

Unfortunately, smallpox may not be completely behind us. A few samples of the smallpox virus were kept for laboratory use after the illness was eradicated - and there is now reason to believe that the virus may have been adapted for use as a weapon.

The possibility of a smallpox outbreak, caused by a deliberate release of the virus, is now regarded as a real possibility. The likelihood of a terrorist attack using smallpox is thought to be very low. However, the consequences of such an attack - if it did occur - would be very serious.

The symptoms of smallpox begin with a high fever, head and body aches and, in some cases, vomiting. After two to four days, a rash appears. The rash spreads, and develops into raised bumps that crust and scab over. After about three weeks, the scabs fall off, leaving pitted scars.

The first symptoms of smallpox usually show up about days after a person has been exposed to the illness, although symptoms can take as little as seven days or as long as 17 days to appear.