Types
There are two types of smallpox – variola major and variola minor. Variola major is the most common and most severe (a more severe rash and higher fever). This type is further broken down into four subtypes – ordinary (the most common, consisting of 90% of the cases. pustules could form intermittently over the body, or even be so numerous that not one clean patch of skin would be left), hemorrhagic (Very rare and very severe. The virus causes blood vessels to seep from all parts of the body, even within the eyes. Unable to move or speak, patients with hemorrhagic pox often are aware of what is happening to them almost to the point of death. ), modified (develops in those that have been previously vaccinated – usually mild), and flat (the pustules never raise up, but are discolorations in the skin that cause it to slough off). Hemorrhagic and flat are usually fatal. Overall, variola has 30% death rate. Variola minor, is much less common and less severe. It only carries a 1% death rate. No one knows exactly how the variola virus ultimately kills someone, but scientists do know that fatality is based on how much of the virus a person is infected with and how strong someone's immune system is.

Transmission
Smallpox is very infectious, in its airborne, aerosolized form, but for it to be spread from person to person, a direct and prolonged face to face contact has to occur. At distances of greater than ten feet, the aerosol begins to break down by the effects of both oxygen, and UV rays from the sun. The virus can also be spread through direct contact with infected body fluids or objects that have been contaminated with infected body fluids. People are the most contagious at the time of onset of the rash, and this lasts until the last smallpox scab falls off. Some cases have also shown to be contagious at the onset of the fever, which occurs before the rash. Humans are the only natural host for the variola virus, and it never been known to be transmitted by insects or animals.

Smallpox as a Bioterrorism Agent
Once smallpox was eradicated from the world, the World Health Organization (1980) ruled that the vaccine no longer needed to be administered. That same year, sources found that Russia began producing the virus to use as a bioweapon. People in the United States had not received the vaccine since 1972. Consequently, most people today carry no immunity for this deadly virus. This fact is the driving force behind the idea of why smallpox is such a serious terrorism threat. The threat of using smallpox as a bioterrorism agent grew even more after the terrorism attacks on September 11, 2001. Although the only two organizations that are known to have stockpiles of the virus are the Centers for Disease Control (CDC) and the Institute of Virus Preparations in Moscow, it is suspected that both Iraq and North Korea also possess a stock of the virus. The list of countries that have smallpox to use as a bioterrorist agent could include other countries, but that information is considered classified. Although nothing is known for certain, the countries of the world and the World Health Organization are making it a top priority to update and monitor their reserves of smallpox vaccine.

Today, a big concern regarding smallpox, is that it will be initially spread in an aerosolized form, by being added to a ventilation system of a large building or through other means such as with crop dusting aircraft. Although these are improbable situations, they still need to be considered, and their consequences planned for. Even if smallpox is introduced into a small area within a city, the virus has the potential to spread throughout the world within a year. Experts estimate that blocking the spread of smallpox released in a single bioterrorism event in a single American city would require a minimum of 30 to 40 million doses of vaccine. With only 90 million doses of vaccine in the whole world in 1998, the affects of a terrorist attack using smallpox could be devastating if more vaccine is not produced.

Even as far back as 1796, before the vaccination was created, smallpox epidemics killed as many as half their victims and crippled entire civilizations. The Aztecs, for instance, were defeated in the 16th century not so much by Hernando Cortes's comparatively puny army as by the smallpox the Spaniards inadvertently brought with them. In the 20th century, smallpox killed 300 million people, far more than all of the century's wars combined. These facts alone, show how potentially dangerous the virus can be to populations of people who do not possess any type of immunization to it.

Vaccination
The smallpox vaccination is a live vaccinia virus, closely related to the variola virus. Although the vaccine has a proven track record, supplies of the vaccine are very limited presently. In 1998, there were 90 million declared doses of the smallpox vaccine around the world. The potency of these doses is unknown, and various countries were attempting to determine whether new vaccines needed to be generated. In 1999, countries started testing the potency of their vaccines. Currently, a division of the World Health Organization in the Netherlands tests specimens every 5 years. Properly stored, smallpox vaccines have been shown to last 18 years without losing their potency. The vaccination usually provides individuals with immunity for about ten years. If a person does experience symptoms, they are usually less severe. Even when the vaccine becomes less effective in people who are losing immunity, they are still less likely to transmit the virus.

Vaccine Contraindications
Vaccination is contraindicated for certain groups. These include pregnant women, women who are breatfeeding, children younger than 12 months of age, persons with immune disorders or experiencing therapeutically-induced immunosuppression (people who have had an organ transplant, those receiving cancer treatment), persons with HIV infection, have a heart condition with or without symptoms, including conditions such as previous heart attack, angina , congestive heart failure, and cardiomyopathy (heart muscle becomes inflamed and doesn’t work as well as it should), stroke or transient ischemic attack (a “mini-stroke” that produces stroke-like symptoms but not lasting damage), chest pain or shortness of breath with activity (such as walking up stairs), or other heart conditions being treated by a doctor, high blood pressure diagnosed by a doctor; high blood cholesterol diagnosed by a doctor; diabetes or high blood sugar diagnosed by a doctor; a first degree relative (for example, mother, father, brother or sister) with a heart condition before the age of 50; and/or, currently a cigarette smoker. and persons with a history of eczema. If the threat of smallpox becomes so great that administration outweighs not receiving the vaccination, a smllpox immune globulin can be given along with the vaccination, if available. A safer vaccinia-based vaccine, produced in cell culture, is expected to become available shortly. There is also interest in developing monoclonal anti-variola antibody for passive immunization of exposed and infected individuals, which could also be administered to persons infected with HIV..

Current Vaccination Due to Bioterrorism
Currently, in the United States, a plan has been put into action to restart smallpox vaccination administration. The first wave of vaccinations will be mandatory and will be given to approximately 500,000 military and the President, our front lines in the defense against terrorism. The second wave will be for civilians and will be voluntary. They will be offered first to medical staff and various health care workers, then to emergency personel, such as police, fire, and EMS, and lastly to the remainder of the public projected to be sometime in 2004.

Treatment and Containment
There is no specific treatment for smallpox beyond treating the symptoms of the illness. The main concern is to stop the spread of the virus before the possibility of an epidemic occurs. Fortunately, during the time when the illness is the most contagious, people are usually so sick that they confined to their beds, leaving their caregivers as the main concern. People are not contagious before the symptoms of the disease manifest. People are urged to receive the vaccination immediately after a known exposure. Receiving this vaccination up to 4 days after exposure and before the rash has been proven to decrease the severity of the infection protect against an outbreak. People that show signs of smallpox need to be isolated immediately. If hospitals do not have isolation facilities, people should be quarantined to their homes. Those that come into contact with the individual(s) need to be vaccinated. Through thorough and efficient diagnosis and containment of the first cases of the disease, an outbreak can be quickly brought under control. Also, if there is evidence a widespread outbreak, people are encouraged to avoid large crowds.

Infection control measures are vital when attempting to contain the variola virus, both within health care facilities and in homes. Whether caregivers have been vaccinated or not, a gown, gloves, cap, and mask should be worn during any and all contact with an infected person. Any bedding or clothing that come into contact with infected individuals should be treated with hot water and chlorine bleach, if not incinerated. Any medical or personal care instruments and materials should be either autoclaved (if this is an option) or incinerated. Those that have expired due to smallpox should be cremated.

For more inforamtion on the disease aspects of Smallpox, click here

Sources: CDC (Center for Disease Control and Prevention), Yale School of Management,
World Health Organization (WHO), PBS (Public Broadcasting Service), and the New America Foundation