Biological Agents
A biological agent is an infectious disease. They can be naturally
occurring or be used in biological warfare. There are more than 1200
different kinds of biological agents, some of which can be used as
biological weapons. The United States Center for Disease Control (CDC) has
divided the agents which can be used as biological weapons into three
categories, Category A, B, and C.
CDC Comprehensive List of Bioterrorism Agents/Diseases
CATEGORY A
Though these agents are rarely seen in the United States, we must prepare
for them because they pose the greatest risk to our national security.
Specifically they:
- can be easily transmitted from person to person;
- result in high mortality rates and have the potential for major
public health impact;
- might cause public panic and social disruption; and
- require special action for public health preparedness
The CDC has classified 6 biological agents as Category A. They are
listed below.
Anthrax
Anthrax, is an acute infectious disease caused by the bacteria Bacillus
anthracis. It can be highly lethal in its most virulent form. Anthrax most
commonly occurs in wild and domestic herbivores, but it can also occur in
humans when they are exposed to infected animals, tissue from infected
animals, or high concentrations of anthrax spores. The
anthrax vaccine is highly effective at preventing spread of anthrax.
Antibiotics can effectively treat Anthrax, if administered in time. US
Army personnel are now routinely vaccinated prior to active service in
places where biological attacks are considered a threat
Smallpox
Smallpox is a serious, contagious, and sometimes fatal infectious disease.
There is no specific treatment for smallpox disease, and the only
prevention is vaccination. The name smallpox is derived from the
Latin word for "spotted" and refers to the raised bumps that appear on the
face and body of an infected person.
Botulism
Botulism is a rare but serious paralytic illness caused by a nerve toxin
called botulin. Botulin is produced by the bacterium Clostridium
botulinum, and blocks nerve function and leads to respiratory and
musculoskeletal paralysis. The most frequent source is home-canned foods,
prepared in an unsafe manner. Wound botulism occurs when C. botulinum
spores germinate within wounds. Infant botulism occurs when C.
botulinum spores germinate and produce toxin in the gastrointestinal
tract of infants.
Plague
Plague, also referred to as Bubonic plague, is the mortal disease caused
by the bacteria Yersinia pestis, which is spread by fleas and rodents to
human beings. Historically, Plague has reached epidemic and even pandemic
proportions in Asia and Europe. It is primarily a disease of rodents such
as rats, prairie dogs, chipmunks, squirrels and other similar rodents.
Human infection most often occurs when a person is bitten by infected
fleas.
Tularemia
Tularemia (also known as "rabbit fever") is a infectious disease caused by
the bacterium Francisella tularensis. Humans are most often
infected by tick bite or through handling an infected animal. Ingesting
infected water, soil, or food can also cause infection. Tularemia can be
acquired by inhalation; hunters are at a higher risk for this disease
because of the potential of inhaling the bacteria during the skinning
process. Tularemia is not spread directly from person to person.
Viral Hemorrhagic Fevers
Viral hemorrhagic fevers (VHFs) are a group of illnesses that are caused
by several distinct families of viruses: Arenavirus, Filoviridae,
Bunyaviridae and Flavivirus. Some of these cause relatively mild
illnesses, while others can cause severe, life-threatening disease.
Examples include Lassa fever, Marburg virus, Ebola virus, Bolivian
haemorrhagic fever, Korean hemorrhagic fever, and Dengue hemorrhagic
fever.
CATEGORY B
The CDC states these agents are the second highest priority. These are
agents that:
- are moderately easy to disseminate;
- result in moderate morbidity rates and low mortality rates; and
- require specific enhancements of CDC's diagnostic capacity and
enhanced disease surveillance.
Examples of these are Salmonella, Typhus, and Ricin.
CATEGORY C
Third highest priority agents include emerging pathogens that could be
engineered for mass dissemination in the future because of
- availability;
- ease of production and dissemination; and
- potential for high morbidity and mortality rates and major health
impact.
Included in this category are emerging infectious diseases such as
Nipah virus and hantavirus.
