1. What's so select about select agents?

Various US agencies, including the Department of Health and Human Services, deemed more than 80 types of bacteria, viruses, fungi, and toxins as "select agents" after Sept. 11, 2001. These hazardous substances, biological and chemical, were chosen for their threat to the health of humans, animals, and plants. The Centers for Disease Control and Prevention (CDC) allowed scientists to comment on the proposed list and made appropriate changes before finalizing it in the fall of 2002. The Public Health Security and Bioterrorism Preparedness and Response Act of 2002 details the regulation and handling of these agents.

2. Who regulates them?

In the United States, the CDC and the Department of Agriculture (USDA) are responsible for select agent controls, which include lab registrations, researcher background checks, and paperwork regarding use, storage, transfers, and disposal (see p. 45). Other countries have agencies that oversee biosafety...

3. What's the difference between CDC's and USDA's regulations?

CDC's regulations apply to materials dangerous to public health, such as infectious diseases, whereas USDA's rules govern those that threaten animal or plant health and related products, dubbed "high-consequence livestock pathogens and toxins." Researchers working with agents on both lists, called "overlap agents," must get approval from both organizations.

4. Are they all equally deadly?

CDC divides their select agents into three categories based on how easily they spread and how much damage they can do. Those in category A, which include the organisms responsible for anthrax, botulism, smallpox, and plague, have the "highest potential for major public health impact," says the CDC. Category B comprises those that are moderately easy to distribute and cause minimal morbidity and mortality, such as ricin toxin and the bacteria that cause Q fever and brucellosis. Category C includes hantaviruses, yellow fever virus, and other emerging pathogens that are considered less likely to be used as bioweapons.

5. What about the chemical agents?

These substances, which include nerve agents, vesicants, toxins, cyanide, and pulmonary "choking" agents, can be just as deadly as biological agents. In the United States, CDC monitors them also, and the National Institute of Allergy and Infectious Diseases includes them in its strategic biodefense research plan.

- Maria W. Anderson

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