Biological Terrorism Agents

What are biological terrorism agents?

Biological terrorism agents are bacteria or viruses that occur in nature and cause infections or produce toxins (a kind of natural poison). Some common examples are:

• anthrax
• botulism
• plague
• smallpox
• tularemia.

What is anthrax?

Anthrax is a type of bacteria that lives in the soil and forms spores. The spores can be inactive for a long time before they develop into new bacteria. The bacteria and spores can infect animals and people. Anthrax infections can be fatal if not treated early with antibiotics.

You can become infected with anthrax by:

• handling infected animals or animal parts or materials contaminated with the bacteria
• breathing the bacteria or spores into your lungs
• eating undercooked meat from infected animals.

The bacteria are common but infections of animals or people are very rare in the US. Anthrax is not known to spread from person to person.

The 3 types of anthrax infections are:

• Cutaneous (skin) anthrax

  Most (about 95%) naturally occurring anthrax infections happen when the bacteria enter a cut or scrape in the skin. Skin infection begins as a raised itchy bump that looks like an insect bite. In 1 to 2 days the bump becomes a blister and then a painless open sore. The sore is usually 1 to 3 cm (an inch or smaller) in diameter, with a black area in the center. Lymph glands near the sore may swell. Up to 20% of untreated cases of skin anthrax result in death. When skin anthrax is treated with antibiotics, deaths are rare.

• Inhalation anthrax

  Symptoms appear 1 to 6 days after the anthrax bacteria or spores are breathed into the lungs. The first symptoms are like the symptoms of a cold or flu (fever, tiredness, cough). The symptoms may quickly get worse, developing into severe breathing problems and shock. Inhalation anthrax is often fatal if it is not treated until after symptoms appear.

• Intestinal anthrax

  You can get the intestinal form of anthrax by eating contaminated meat. The first symptoms are nausea, loss of appetite, vomiting, and fever. The symptoms then worsen to abdominal pain, vomiting of blood, and severe diarrhea. Intestinal anthrax causes death in 25% to 60% of cases, even with treatment.

Being exposed to anthrax does not mean that you will be infected and get sick. For example, you could have anthrax spores in your nose but not have them in your lungs. Anthrax is diagnosed from your history, physical exam, and lab tests of samples of blood, sputum, stool, or skin. Antibiotics should be given to people who have definitely or probably been exposed to anthrax. If there is a good chance you have been exposed, you may be tested and start treatment with antibiotics at the same time, without waiting for test results.

A vaccine that can help prevent infection with anthrax has been developed but it is not available for everyone. The vaccine is recommended only for people who work with animal hides or furs, people who work with animal products in areas with a high incidence of anthrax, veterinarians who travel to foreign countries, people who work directly with anthrax in the lab, and some military personnel.

To help avoid becoming infected with anthrax when there is a threat of bioterrorism:

• Do not handle suspicious letters, packages, or other objects.
• Avoid eating meat that has not been properly cooked.

Call your healthcare provider or go to the emergency room if you live or work in a setting where anthrax has been locally reported AND you have fever, chest pain, and muscle aches.

Also call your healthcare provider if:

• You have a suspicious skin sore.
• You live or work in an area where anthrax has been locally reported AND you have suspicious cold or flulike symptoms or unexplained nausea, vomiting, and diarrhea.

What is botulism?

Like anthrax, botulism is caused by bacteria that naturally live in the soil. The toxin produced by these bacteria causes paralysis and is one of the deadliest substances known to man. Even a tiny amount can be fatal. Death usually occurs when the muscles needed for breathing become paralyzed.

Eating food that is infected with botulism bacteria is the usual cause of infection. Poorly preserved canned foods are the most common example. However, you can also become infected or poisoned by inhaling the bacteria or toxin, or by getting bacteria in a wound.

The symptoms of botulism may begin within a day or two of exposure to the bacteria, but sometimes symptoms may not appear for several days. The symptoms are:

• blurred vision and problems focusing
• trouble swallowing, speaking, or breathing
• vomiting
• weak muscles.

The diagnosis of botulism is made from your history and physical exam. Samples of your blood or bowel movement may be tested in the lab.

A medicine called an antitoxin is available to treat the infection. People infected with botulism sometimes need a machine called a ventilator to help them breathe until they recover.

Botulism isn't contagious. Terrorist releases of botulinum toxin in the air pose little risk beyond the immediate time of release. The bacteria that cause botulism are killed by chlorine. (Chlorine is added to most water supplies in the United States.) If you suspect food is contaminated, you can destroy the toxin by boiling the food for 10 minutes. If you suspect that a surface is contaminated, it can be cleaned with soap and water or a bleach solution. The toxin will not harm your skin, although you can get infected if the bacteria enter your body through a wound.

Call your healthcare provider if you live or work in an area where botulism has been locally reported AND you start having muscle weakness, new constant blurry vision, and trouble swallowing, speaking, or breathing.

What is plague?

The bacteria that cause plague are usually spread by fleas that feed on infected rodents, such as rats. The fleas infect people by biting them. Plague that starts this way is called bubonic plague. However, the plague can also be spread through the air. If an infected person develops pneumonia from the plague, it is called pneumonic plague and it can be spread from person to person by coughing, sneezing, or even just talking. Plague can be fatal if it is not treated early.

The first signs of bubonic plague are fever, chills, weakness, and tender lymph nodes 2 to 10 days after a flea bite. Bubonic plague can spread to the blood, lungs, and nervous system.

The first signs of pneumonic plague are fever, chills, headache, weakness, and coughing with bloody or watery sputum. These symptoms usually appear 1 to 6 days after exposure. The pneumonia gets worse over 2 to 4 days. Pneumonic plague can cause shock and death if it is not treated within 24 hours of the start of symptoms.

Plague is diagnosed from your history, physical exam, and lab tests of a sample of tissue from an infected lymph node.

When plague is treated early with antibiotics, the infection is usually not fatal.

Antibiotic treatment for 7 days can protect you from infection if have had close contact with someone who has pneumonic plague. A vaccine for plague is not currently available in the US, but researchers are working on developing one.

Call your healthcare provider if you live or work in an area where plague has been locally reported AND:

• You have a fever.
• You have a new persistent cough with bloody or large amounts of sputum.
• You have had close contact (within 6 feet, or 2 meters) with someone known to have untreated pneumonic plague.

What is smallpox?

Smallpox is caused by the variola virus. It is spread from person to person by droplets of saliva (coughing and sneezing). The virus causes fever and a rash. It is fatal in about 1 out of every 3 people who get the infection.

Naturally occurring smallpox has been eliminated. There have been no reports of smallpox infections anywhere in the world since 1977. Small amounts of the virus have been kept for research purposes and there is a risk that smallpox could be used for biological terrorism.

Symptoms of smallpox appear about 12 days after exposure. Some of the first symptoms are high fever, fatigue, headache, and backache. Two to four days later a rash appears. Blisters develop, which become scabs in 1 to 2 weeks. Smallpox is diagnosed from your symptoms, physical exam, and lab tests of fluid samples from your mouth or from the blisters.

Antibiotics are not effective against this viral disease, and no antiviral treatment is known to be effective against smallpox. Supportive care (IV fluids and antibiotics to prevent bacterial infections that can occur with smallpox) can help but will not cure the disease.

The smallpox vaccine was given to most people until 1972, when the US decided to stop routine smallpox vaccinations. The vaccine was causing side effects and there was almost no risk of getting smallpox at this time. The US does have an emergency supply of smallpox vaccine. Some vaccines provide protection against illness only if they are given weeks or months before exposure to the illness. However, the smallpox vaccine can protect you even when given 2 to 4 days after exposure to the disease. It may prevent you from getting smallpox or it may lessen the severity of illness. If you were vaccinated before vaccinations stopped being given in 1972, it is likely that you are no longer protected against the disease because immunity weakens over time.

Call your healthcare provider if you live or work in an area where smallpox has been locally reported AND:

• You think you have been exposed to someone who has smallpox.
• You have fever, chills, headache, nausea, vomiting, and severe muscle aches.
• You develop a rash after 2 to 4 days.

What is tularemia?

Tularemia is caused by bacteria that spread to humans by the bite of a tick, fly, or mosquito, or from contact with infected animals, such as rabbits or deer. You can also become infected by breathing in contaminated dust or air, drinking contaminated water, or eating the meat of an infected animal without cooking it well first. Tularemia is not known to spread from person to person.

The illness can affect the body in different ways. Symptoms appear within a few days of exposure. Some of the symptoms are fever and chills, headache, nasal congestion, sore throat, cough, abdominal or back pain, stiff neck, skin ulcers, diarrhea, and vomiting. The diagnosis is based on your symptoms, history of possible exposure, and lab tests of samples of blood and sputum.

Tularemia can be treated with several common antibiotics. With treatment, this disease is usually not fatal.

A shot of an antibiotic given soon after exposure can prevent illness. An experimental vaccine to protect against tularemia has been developed but is not yet available.

If the bacteria that cause tularemia are on a surface or in water, they can be killed by chlorine.

Call your healthcare provider if you live or work in an area where tularemia has been locally reported AND:

• You have unexplained muscle, abdominal, or back pain.
• You have fever that doesn't go away in 2 to 3 days.
• You have cold symptoms that do not get better in 7 to 10 days.

What are viral hemorrhagic fevers (VHFs)?

Viral hemorrhagic fevers (VHFs) are a group of viruses that could be used for bioterrorism. Examples of VHFs include Ebola virus, hantavirus, yellow fever, Lassa fever, and Marburg virus. While some types of hemorrhagic fever viruses can cause relatively mild, flulike illness, many of the viruses cause severe, life-threatening disease.

The viruses are carried by some types of animals, and they are usually found in the areas where these animals live. Most are in sub-Saharan Africa, but some of the viruses can be found in many parts of the world, including the US. Usually the infections are spread to humans by rodents such as rats and mice, and also by fleas and ticks. Some of the viruses can spread from person to person. These viruses could be used for bioterrorism if they were put into weapons or spread through the air.

Because people are usually infected with these illnesses in rural areas outside the US, a history of where you have traveled is important in the diagnosis. Cases of hantavirus have occurred mainly in the American Southwest after exposure to infected rodent droppings (feces).

Infections with these viruses can cause many of the organs in the body to stop working properly. The first signs and symptoms often include high fever, tiredness, dizziness, muscle aches, and weakness. People with severe cases of VHF often show signs of bleeding under the skin, in internal organs, or from body openings such as the mouth, eyes, or ears. However, although they may bleed from many places around the body, blood loss is rarely the cause of death. Severe infections may cause shock, coma, delirium, and seizures.

For the most part there is no specific treatment for viral hemorrhagic fevers. If you have symptoms of viral hemorrhagic fever, see your healthcare provider right away.

What should I do if I think I may have been exposed to a biological terrorism agent?

It is important to remain calm yet vigilant. Most of the most dangerous biological terrorism agents act slowly. If they are identified and treated early, they are usually not fatal. If you have been or are currently in an area where biological agents have been identified AND you have suspicious symptoms, report them to your healthcare provider.