Treating Chemical and Biological Agent Casualties

Lesson 4: Biological Agents

4-3. TYPES OF BIOLOGICAL AGENTS

Bacteria, viruses, rickettsia, and toxins may be used as biological agents in modern warfare. Of these, toxins are probably the most effective.

a. Bacteria. Bacteria are living, one-celled organisms. Often, diseases caused by bacteria are carried by animals which transmit the disease to man. Examples of bacterial diseases include anthrax, cholera (actually caused by an enterotoxin produced by bacteria), dysentery, malaria, meningitis, plague, tularemia, and typhoid.

b. Viruses. Viruses are submicroscopic pathogens composed of nucleic acid that invade living cells, take over the cell's reproductive function, causes the cell to reproduce the virus, and eventually destroys the cell. Viruses are often transmitted to humans by arthropods, rodents, monkeys, and other humans. Examples of viral diseases include hemorrhagic fever, viral hepatitis, and smallpox.

c. Rickettsia. Rickettsia are very small microscopic organisms, considered to be a type of bacteria, that reproduce only inside a host cell. They are usually carried by ticks, lice, or fleas. Examples of diseases caused by rickettsia include typhus, spotted fever, and query fever (Q fever).

d. Toxins. Toxins are chemical compounds of biological origin. Their origin and their ability to affect the human immune system separate them from other poisons. The advent of biotechnology has changed the magnitude of the toxin threat. Toxins that are only available in small amounts in nature can be produced in large quantities using bioengineering techniques. Bioengineering may also allow subtle changes in the toxins that do not alter their toxic properties but decreases the body's natural ability to neutralize the toxins. The ability to produce large quantities of toxins, the ability to manipulate their structure, and the ability to target them for specific cells have greatly increased their potential as effective biological warfare agents.

(1) Mycotoxins. Mycotoxins attack and kill specific types of cells. They may affect the body's respiratory, circulatory, digestive, or integumentary systems.

 

(2) Neurotoxin. Neurotoxin interfere with nerve impulse transmission.

 

(3) Bacterial toxins. Bacterial toxins are derived from bacteria. Neurotoxin produced by certain species of bacteria are among the most poisonous substances known. These toxins produces diseases such as botulism and tetanus.

 

(4) Saxitoxin. Saxitoxin are neurotoxin which are produced by certain marine plankton. The neurotoxin can accumulate in shellfish, such as mussels and clams, which feed upon the plankton.

 

(5) Tetrodotoxins. Tetrodotoxins are neurotoxin which are present in several species of puffer fish.

 

(6) Phytotoxin. Phytotoxin are neurotoxin produced by certain species of higher plants, such as ricin produced by the caster bean which is 100 times more deadly than cobra venom.

 

(7) Mycotoxins. Mycotoxins are toxins produced by fungi. They are sometimes referred to as "yellow rain."