Biological Terrorism: Know The Facts About Anthrax and Smallpox

The “threat of Biological Terrorism” has been heard often in the news since the attacks on September 11th. Though the risk is very low that you will encounter this kind of warfare, it is important to know the facts.

Biological terrorism is the intentional use of toxic micro-organisms to harm or kill people. Terrorists are most likely to use organisms that can be easily spread among people, such as infectious diseases.

Anthrax

• Infection by skin contact: Most cases occur by skin contact. Skin infection begins as a raised itchy bump that looks like an insect bite. Within 1-2 days, it develops into a boil-like sore and then a painless ulcer with a characteristic dark (dying) area in the center. The infection can also cause swelling of the lymph glands near the site. About 20% of untreated cases will result in death. With proper treatment, deaths from this type of anthrax are rare.

• Infection by inhalation: People who get anthrax by breathing in spores have symptoms that are like a common cold. After several days, the symptoms can progress to severe breathing problems and shock. This type of anthrax usually results in death in 1-2 days after the start of severe symptoms.

• Infection by ingestion: Intestinal infections from eating contaminated meat are rare. The infection causes severe inflammation of the intestinal tract. The first signs are nausea, loss of appetite, vomiting, and fever, followed by abdominal pain, vomiting of blood, and severe diarrhea. Intestinal anthrax results in death in 25% to 60% of cases.

Smallpox

Smallpox is caused by variola virus. The incubation period is about 12 days (range: 7 to 17 days) following exposure. Initial symptoms include high fever, fatigue, and head and back aches. A characteristic rash, most prominent on the face, arms, and legs, follows in 2-3 days. The rash starts with flat red lesions that evolve at the same rate. Lesions become pus-filled and begin to crust early in the second week. Scabs develop and then separate and fall off after about 3-4 weeks. The majority of patients with smallpox recover, but death occurs in up to 30% of cases.

Smallpox is spread from one person to another by infected saliva droplets that expose a susceptible person having face-to-face contact with the ill person. Persons with smallpox are most infectious during the first week of illness, because that is when the largest amount of virus is present in saliva. However, some risk of transmission lasts until all scabs have fallen off.

Routine vaccination against smallpox ended in 1972. The level of immunity, if any, among persons who were vaccinated before 1972 is uncertain; therefore, these persons are assumed to be susceptible.

Vaccination against smallpox is not recommended to prevent the disease in the general public and therefore is not available.

In people exposed to smallpox, the vaccine can lessen the severity of or even prevent illness if given within 4 days after exposure. Vaccine against smallpox contains another live virus called vaccinia. The vaccine does not contain smallpox virus.

The United States currently has an emergency supply of smallpox vaccine.

There is no proven treatment for smallpox but research to evaluate new antiviral agents is ongoing. Patients with smallpox can benefit from supportive therapy (intravenous fluids, medicine to control fever or pain, etc.) and antibiotics for any secondary bacterial infections that occur.

(Source: The Centers for Disease Control)