By Nancy Menefee Jackson, HealthAtoZ contributing writer
Second of two parts
There were two kinds of terror attacks on the United States in 2001: the suicide airliner crashes, and the envelopes laced with anthrax.
These attacks brought home to Americans the powerful weapons that could fall into the hands of terrorists.
The Centers for Disease Control and Prevention has identified the six highest-risk biological agents that could be used to kill Americans and disrupt day-to-day life.
Anthrax. Naturally occurring, anthrax is acquired from animals or animal products. Animals, especially herbivores such as sheep and cattle, get anthrax from ingesting Bacillus anthracis spores found in soil. Inhalation (inhaled) anthrax is the route that would be used in bioterrorism. Since 1976, there had not been a single case of inhaled anthrax in the U.S. until the attacks in 2001, which killed five people.
Symptoms are malaise, fever, cough, muscle aches, sore throat, difficulty breathing, chest pain, nausea, vomiting and headache. A vaccine is available.
Botulism. Development of the botulinum toxin as a possible weapon began 60 years ago. Terrorists attempted to use it at least three times in Japan between 1990 and 1995. They obtained C. botulinum from soil. Naturally occurring botulism is foodborne or occurs in wounds. It has been aerosolized for weapons use. Botulism causes paralysis, and victims have difficulty seeing, speaking and swallowing. Death can result from airway obstruction or respiratory muscle paralysis. An antitoxin is available.
Plague. Carried by fleas and responsible for the Black Death pandemic in the 1300s that killed millions, plague is no longer a threat, thanks to improved living conditions, public sanitation and antibiotics. Small outbreaks do occur throughout the world and even in the United States. Fleas carry the bubonic form of the disease, which does not spread among people unless the fleas are present. But a small percentage of patients develop a secondary pneumonic plague that can be spread by infected airborne droplets, and biological weapons programs have developed aerosol versions of pneumonic plague. A plague outbreak caused by terrorists would result in symptoms resembling other severe respiratory illness, including fever, labored breathing and cough with bloody or watery sputum. If these symptoms were left untreated, patients would be in danger of respiratory failure, shock and rapid death. Researchers are pursuing a vaccine. Certain antibiotics are effective against plague.
Smallpox. A virus, smallpox is a serious threat because it has a 30 percent fatality rate. A vaccine is available, but routine vaccinations ceased more than two decades ago, when the disease was eradicated in a massive global health effort. The last case occurred in 1977. Because it spreads easily by droplets, contaminated clothes and bedding, smallpox is one of the most feared of all diseases. Symptoms include high fever, malaise, headaches and backaches. Patients become most infectious when the characteristic rash appears on the face, mouth and forearms, eventually spreading to the trunk, legs, hands and feet. Those who do survive the disease have disfiguring pitted scars. Vaccination administered within three to seven days of exposure may prevent or lessen the severity of the disease.
Tularemia. Tularemia is a serious illness caused by Francisella tularensis, an extremely infectious bacterium. This bacterium resides in small animals such as mice, rabbits and squirrels. A plague-like disease, Tularemia has been feared as a weapon because it is potent and easy to disseminate. It was stockpiled by the United States in the 1960s; those stockpiles were destroyed by 1973. The early symptoms are similar to flu or pneumonia, with fever, chills, headache, sore throat, diarrhea, cough and muscle aches. If used as biological weapon, the bacteria would probably be made airborne for inhaled exposure leading to severe pneumonia, which could be life-threatening. A vaccine is under review by the Food and Drug Administration, but is not currently available in the U.S. Tularemia can be effectively treated with antibiotics.
Hemorrhagic fever viruses. These are fearsome diseases, such as Ebola, Marburg, and Lassa fever, among others, that have been seen in sporadic outbreaks worldwide. The Japanese terrorist cult Aum Shinrikyo tried unsuccessfully to obtain the Ebola virus. These viruses live on animals. Humans become infected through a bite, through rodent droppings or through handling or eating infected meat. They can then spread some hemorrhagic fever viruses through close contact. Symptoms include fever, muscle aches, and exhaustion. In later stages, patients may hemorrhage and go into shock. The only treatment currently available is a therapy that tries to maintain circulation. No vaccine is available, nor is general drug treatment, although an antiviral agent, ribavirin, successfully treats some people with certain hemorrhagic fever viruses.
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External Source
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Centers for Disease Control and Prevention, Biological Agents/Diseases
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This article was reviewed and updated June 2007.
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