Biological agents are organisms or toxins that can kill or incapacitate people, livestock, and crops. The three basic groups of biological agents that would likely be used as weapons are bacteria, viruses, and toxins. Most biological agents are difficult to grow and maintain. Many break down quickly when exposed to sunlight and other environmental factors, while others, such as anthrax spores, are very long lived. Delivery methods include: 

Aerosols - biological agents are dispersed into the air, forming a fine mist that may drift for miles. Inhaling the agent may cause disease in people or animals.

Animals - some diseases are spread by insects and animals, such as fleas, mice, flies, mosquitoes, and livestock.

Food and water contamination - some pathogenic organisms and toxins may persist in food and water supplies. Most microbes can be killed, and toxins deactivated, by cooking food and boiling water. Most microbes are killed by boiling water for one minute, but some require longer. Follow official instructions.

Person-to-person - spread of a few infectious agents is also possible. Humans have been the source of infection for smallpox, plague, and the Lassa viruses.

In the event of a biological attack, it may take time to determine what the illness is, how it should be treated, and who is in danger. Watch television, listen to radio, or check the Internet for official news and information including signs and symptoms of the disease, areas in danger, if medications or vaccinations are being distributed, and where you should seek medical attention if you become ill.

The first evidence of an attack may be when you notice symptoms of the disease caused by exposure to an agent. Be suspicious of any symptoms you notice, but do not assume that any illness is a result of the attack. Use common sense and practice good hygiene.

If you become aware of an unusual and suspicious substance nearby:

• Move away quickly.
• Wash with soap and water.
• Contact authorities.
• Listen to the media for official instructions.
• Seek medical attention if you become sick.

If you are exposed to a biological agent:

• Remove and bag your clothes and personal items. Follow official instructions for disposal of contaminated items.
• Wash yourself with soap and water and put on clean clothes.
• Seek medical assistance. You may be advised to stay away from others or even quarantined.

Using HEPA Filters

High Efficiency Particulate Air (HEPA) filters are useful in biological attacks. If you have a central heating and cooling system in your home with a HEPA filter, leave it on if it is running or turn the fan on if it is not running. Moving the air in the house through the filter will help remove the agents from the air. If you have a portable HEPA filter, take it with you to the internal room where you are seeking shelter and turn it on.

If you are in an apartment or office building that has a modern, central heating and cooling system, the system’s filtration should provide a relatively safe level of protection from outside biological contaminants.

HEPA filters will not filter chemical agents.