Biological Agents

Biological agents include bacteria, viruses, fungi, other microorganisms, and their associated toxins. They can adversely affect human health in a variety of ways, ranging from relatively mild allergic reactions to serious medical conditions or death. Some organisms, such as various types of mold and Legionella bacteria, can be found in the environment. Spreading from person to person (e.g., bloodborne pathogens and influenza viruses), either directly or indirectly, can occur; others, such as Zika and West Nile virus, are transmitted by insect vectors. In some forms, biological agents can also be weaponized for use in bioterrorism or other crimes.

Chemical Agents

Chemical agents or chemicals are present in every home and workplace, such as cleaning supplies, ink toner, paint thinner, adhesives, paints, and oils.  The term chemical agent includes any chemical element or compound that occurs in the natural environment or as produced, used, or released (including release as a waste product) by any activity, whether or not it was produced intentionally and whether or not it was placed on the market.  Chemical agents have the potential to cause harm to human health.  Chemical releases can be unintentional, such as an industrial accident, or intentional in the case of a terrorist attack.  Chemical weapons can be easy to produce, but their effectiveness as a weapon is limited by factors such as their purity, quantity of the agent, how they are dispersed, or weather such as wind direction. 

Infectious Diseases

Infectious diseases, also called communicable diseases, are disorders that are caused by organisms such as bacteria, viruses, fungi, or parasites that are passed, directly or indirectly, from one person to another.  These germs can spread from person to person, through contaminated food or water, by insect bites, or from the environment.  Humans can also become infected following exposure to an infected animal that has a pathogenic organism that is capable of infecting humans.  Many infectious diseases can be avoided by getting vaccinated, maintaining good hygiene, and avoiding close contact with sick individuals.  

Respiratory Illnesses

Respiratory Illnesses are conditions affecting the lungs and airways that impair breathing and can cause symptoms like coughing, wheezing, and shortness of breath. 

Vector-borne Diseases

Vector-borne Diseases are caused by living organisms that can transmit infectious pathogens between humans or from animals to humans. The distribution of vector-borne diseases is determined by a complex set of demographic, environmental, and social factors. Global travel and trade, unplanned urbanization, climate change, and the silent spread and adaptation of the vectors have all contributed to the spread of vector-borne diseases. 

Food-borne Illnesses

Food-borne illnesses are caused by contamination of food and occur at any stage of the food production, delivery, and consumption chain. They can result from several forms of environmental contamination, including pollution in water, soil, as well as unsafe food storage and processing.