|
Pharmacology => Drug => SmallPox
SmallPox
Smallpox, acute, highly contagious viral disease that is often fatal. Once considered a fairly prevalent disease that developed in epidemics around the world, smallpox now appears to have been completely eradicated.
The smallpox virus is transmitted through droplets discharged from the mouth and nose of an infected person that are inhaled by another person. Onset of the first phase of smallpox infection occurs after a 12-day incubation period following infection. This phase is marked by high fever, prostration, back and muscle pain, and sometimes vomiting. A characteristic rash develops two to five days later on the face, the palms, and the soles of the feet. During the next six to ten days the rash develops into pustular (pus-filled) pimples. In extreme cases the pustular pimples run together, which usually indicates a lethal infection of the virus. The return of fever and related symptoms initiates the second stage of disease, during which the pustules may become secondarily infected by bacteria. As recovery begins, the pustules become crusted, often leaving scars, and the fever and related symptoms subside. Death is caused by infection of the lungs, heart, or brain. Blindness and male infertility are possible side effects of smallpox among survivors. A person with smallpox is infectious from about the third day through the erupting phase. Survivors usually experience long-term immunity to the disease.
In 1967 the United Nations World Health Organization (WHO) launched a worldwide vaccination campaign against smallpox. At the time, about 10 to 15 million cases of the disease occurred each year, with more than 2 million deaths. By mid-1975 when all India was declared free of smallpox, only a few cases were left in two countries, Bangladesh and Ethiopia. In 1979, after two years without a reported case of smallpox, the WHO marked the disappearance of smallpox from the earth. It recommended that countries stop vaccinating against smallpox and that laboratory stocks of the virus be destroyed. Underlining the importance of the latter request was the death of an English woman in 1979 from smallpox contracted in a laboratory while working with the virus.
Stocks of the virus now exist only at the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, and the Russian State Research Center of Virology and Biotechnology in Koltsovo, Russian Federation. In 1996, the WHO initially resolved to destroy the remaining stocks of smallpox virus on June 30,1999. But in May 1999, the WHO decided to temporarily postpone destruction of the virus until at least the year 2002. This delay is intended to foster continued research into antiviral agents, improved vaccines, as well as the natural and synthetic permutations of the smallpox virus that may cause the disease's unexpected revival.
Back
|
