Smallpox is a well-known infectious agent of the past. The “pox” in the title is plural for ‘pocke’, which means sac. ‘Pox” is also Latin for spotted and refers to the bumps it produces on infected persons. The name ‘smallpox’ first occurs in Holinshead’s Chronicles from 1571, and is named in order to distinguish it from syphilis, the ‘great pox’. Smallpox is a member of the Orthopoxvirus genus and the Poxiviridae family. The last case of smallpox in the United States was in 1949. The last naturally occurring case globally was in Somalia in 1977. The most recent known laboratory case infection was caused by accident in 1978 in Birmingham, England. Outbreaks have happened from time-to-time but have eradicated after a successful worldwide vaccination program. After the disease was eliminated from the world, routine vaccination among the public was stopped and no longer necessary for prevention.
The first suspicion of smallpox occurred very early on in history. Smallpox has seemed to emerge in human populations around 10,000 BC, and has since then spread from Africa, to globally everywhere. Scientists believe it spread from Africa to India by Egyptian merchants. The earliest evidence of skin lesions resembling smallpox are found on mummies from about 1570 BC. Later on, smallpox was reported in China and India around 1122 BC. Then, smallpox was introduced to Europe between 400 and 600 CE. In the past, survivors of smallpox became nurses for the infected since they were now immune to the disease. It was an epidemic during the middle ages and greatly affected the development of the west. “Some experts say that over the centuries it has killed more people than all other infectious diseases combined” (nlm.nih.gov). Movies and shows often reflect smallpox very dramatized and with many misconceptions. Inevitably, the virus spread throughout the world and affected all levels of society.
The virus appears in two different types. There is Variola major, which is severe and more common, and Variola minor, which is less common and less severe. Variola major has four subsets of infections. “Ordinary” is the most frequent type, making up about 90% of all smallpox infections. “Modified” is milder and occurs in vaccinated persons. “Flat” and “Hemorrhagic” are more rare and severe and usually fatal. Overall, Variola major is a more extensive rash and higher fever and has a fatality rate of 30%. Variola minor is less common and less severe with a fatality rate of less than 1%. The two different types are easily distinguished by their symptoms.
A virus causes the smallpox infection in humans. The name of the infectious agent causing smallpox is the Variola virus. Since world vaccination, it has been eliminated except for tightly regulated laboratory stockpiles. After 9/11, people became greatly concerned that the virus might be used as an agent for bioterrorism, since it is known as a Bioterrorism Agent Category A, and the general public is no longer vaccinated for it. In the early 1980’s the agreement was fulfilled that the remaining stocks of the virus would either be destroyed or sent to one of two secure laboratories, one in the United States and one in Russia. Though it is tightly regulated, one cannot help but consider this virus to be a dangerous weapon.
The genetic characteristics of the Variola virus are very distinct from other viruses since it specifically infects human hosts. The virus particles are egg-shaped and brick-shaped. The Variola virus is about 200-400 nm and have a genome that is 200 kilobase pairs long. A kilobase is the length of nucleic acid molecules in thousands. It is one of the largest animal viruses. The pathogen is pleomorphic, which means they can alter their shape or size in response to environmental conditions. Additionally, the virus contains a nucleocapsid that is typically dumbbell-shaped. In order to infect humans, the virus’s