Smallpox

Smallpox is a highly contagious disease that is caused by the variola virus. Initial symptoms of this disease are similar to those of a flu, but a characteristic rash will typically follow within days. Although outbreaks used to be common, a vaccine was eventually created, and the disease was eradicated worldwide by 1980. What Is Smallpox? Smallpox is a serious, highly contagious, and sometimes fatal disease. The name smallpox is derived from the Latin word for "spotted," which refers to the raised bumps that appear on the face and body of an infected person. Thanks to the success of vaccination, the last natural outbreak of smallpox in the United States occurred in 1949. By 1972, routine vaccinations for children in the United States were no longer needed. In 1980, the disease was said to be wiped out worldwide, and no cases of naturally occurring smallpox have occurred since then. What Causes It? The cause of smallpox is an infection with the variola virus. Variola virus is a double-stranded DNA virus in the family Poxviridae and the genus Orthopoxvirus. Variola virus only infects humans. Different Types of Smallpox There are 2 clinical forms of smallpox: variola major and variola minor. Variola major is the severe and most common form of smallpox, characterized by a more extensive rash and higher fever. There are 4 types of variola major smallpox: * Ordinary (the most frequent type, accounting for 90 percent or more of cases) * Modified (mild and occurring in previously vaccinated persons) * Flat * Hemorrhagic. Both flat and hemorrhagic are rare and very severe conditions. Historically, variola major has an overall mortality rate of about 30 percent. Flat and hemorrhagic smallpox are almost always fatal. Variola minor is a less common presentation of smallpox, and a much less severe disease, with death rates historically of 1 percent or less. How Is It Transmitted? Smallpox is highly contagious. In most cases, transmission occurs by inhaling droplets of saliva, which are full of virus, during face-to-face contact with an infected person. Usually, fairly prolonged face-to-face contact (3 or more hours) is required. Other, less-common ways that smallpox is spread include: * Direct contact with infected fluids and contaminated objects * Through the air. Incubation Period When a person becomes infected with the virus that causes smallpox (variola), the virus begins to multiply within the body. After 7 to 17 days (the average is 12), smallpox symptoms can begin. This period between the transmission of the virus and the start of symptoms is the "smallpox incubation period." Symptoms of Smallpox Once symptoms begin, the first smallpox symptoms may be hard to distinguish from other flu-like illnesses. After a couple of days, a person with symptoms will begin to develop a smallpox rash. Over the next couple of weeks, this rash will go through various stages. Diagnosis In order to make a diagnosis, the doctor will ask a number of questions and perform a physical exam, looking for signs and symptoms of smallpox. This will include a skin and mouth exam to look for the smallpox rash. If there is a moderate or high suspicion of smallpox, the doctor may order certain lab tests, refer the person to a dermatologist or infectious disease doctor, and/or call health authorities for their recommendations. Before a diagnosis is made, the doctor will also consider other illnesses that can share similar signs and symptoms with smallpox. Some of these illnesses can include: * Chickenpox * Monkeypox * Herpes zoster (shingles) * Contact dermatitis * Erythema multiforme * Hand, foot, and mouth disease * Impetigo * Adverse reaction to medications * Scabies * Molluscum contagiousum. How Is It Treated? There are currently no proven treatments that can kill the smallpox virus. Therefore, treatment focuses on providing relief of symptoms as the body fights the virus. This is called supportive care. Prevention If smallpox were to return, prevention would include: * Vaccination with the smallpox vaccine * Certain health authority measures. Why Smallpox Is a Concern In the aftermath of the events of September and October, 2001, there is heightened concern that the variola virus might be used as an agent of bioterrorism. The deliberate release of smallpox is now regarded as a possibility, and the United States is taking precautions to deal with this threat. The Centers for Disease Control and Prevention (CDC) calls the variola virus a "Category A" agent. Category A agents are believed to present the greatest potential threat for harming public health and have a moderate to high potential for large-scale dissemination. Other Category A agents are: * Anthrax * Botulism * Plague * Tularemia * Viral hemorrhagic fevers. History of Smallpox Smallpox was described in Asia during the first century, in Europe and Africa around 700 A.D., and in Central, South, and North America during the 16th and 17th centuries. Some health experts believe that smallpox, over the centuries, has been responsible for more deaths than all other infectious diseases combined. Thanks to the success of a worldwide vaccination program, smallpox has been eradicated. The last naturally occurring case in the world was in Somalia in 1977. In 1980, the World Health Organization officially said that smallpox was wiped out worldwide, and no cases of naturally occurring smallpox have happened since. After variola virus was eliminated from the world, routine vaccination against smallpox among the general public was stopped because it was no longer necessary for prevention.