what is smallpox?
Smallpox was the world's deadliest disease. It was often referred to as the "speckled monster" due to the pustules that erupted on the skin from the disease. The last reported case of the disease was in 1977, and eradication was achieved due to mass increases of vaccination.
Smallpox killed on average one third of those that it infected. There are two forms of smallpox, that originate from the Variola virus: Variola major, the more severe form, and Variola minor. It is currently classified as a Category A agent by the Centres for Disease Control and Prevention. This categorization is defined as the "greatest potential threat for adverse public impact".
Variola major can be divided into four types:
Variola minor accounted for less than 1% of death rates, and was far less severe overall.
Variola major can be divided into four types:
- Ordinary (accounted for 90% of cases)
- Modified (mild, typically in those that were previously vaccinated)
- Flat
- Hemorrhagic (severe)
Variola minor accounted for less than 1% of death rates, and was far less severe overall.
origin
Smallpox is believed to have developed in human populations thousands of years ago, possibly around the beginning of domestication of civilization. Some experts denote the origin of smallpox as somewhere in East Africa nearly 40,000 years ago.
transmission
The typical method of transmission is through face to face contact, bodily fluid contact, or contact with contaminated objects. It was rarely spread via airborne measures. Humans are the specific hosts of smallpox. While it is believed that the virus mutated from an original animal host, it is not known to be transmitted by plants or animals.
exposure period
- Incubation Period (7-17 days): during this period, people may exhibit any symptoms, and are not contagious.
- Initial Symptoms/Prodrome Phase (2-4 days): some symptoms such as fever, malaise, body aches and vomiting may develop during this time. People in this stage are sometimes contagious, and typically have high fevers ranging from 101-104 degrees Fahrenheit.
- Early Rash (4 days): This phase is categorized as the most contagious, as individuals develop spots within their mouth, as well as sores that break open, allowing the virus to spread quickly. Rash would develop all over the skin within 24 hours, and often times the fever would fall and the individual would feel better. However, by the third day, the rash would develop into bumps, and by the fourth day, bumps would fill with thick, dark liquid with a depression in the centre. At this time fever would increase until scabs turned into bumps.
- Pustular Rash (5 days): Pustules develop from bumps, typically round in shape and firm to the touch. Person remains contagious.
- Pustules and Scabs (5 days): The individuals's pustules, which remain contagious, would develop into scabs.
- Resolving Scabs (6 days): Scabs develop into scars within three weeks, and the person remains contagious until all scabs have fallen off.
- Resolved Scabs: The individual is no longer contagious, and scabs have subsided.
The media, through various movies and television programs, depict smallpox as having higher contagious capabilities than it actually does. For example, in the movie Smallpox, it depicted one person as infecting 20 other individuals, whereas experts depict that a more accurate model would be one person infecting 5 other individuals. Many fear that smallpox could be potentially used for bioterrorism, however there are only two samples of the virus in existence, both of which are in high security locations. Here is a link to the CDC's Smallpox Response Plan.
treatment
There is no treatment for the disease. The only available medication is used to treat the cold and flu symptoms of the disease. Prevention through vaccination is the only "treatment" available. In vaccination, two-pronged needles are used, and often times bumps develop at the site.
See the World Health Organization Smallpox Eradication Programme here.
See the World Health Organization Smallpox Eradication Programme here.