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Tribhuvan University Journal of Microbiology-Vol 4(1)

Bioterrorism; An emerging threat to World

Bioterrorism

A bioterrorism attack is the deliberate release of viruses, bacteria, or other germs (agents) used to cause illness or death in people, animals, or plants. These agents are typically found in nature, but it is possible that they could be changed to increase their ability to cause disease, make them resistant to current medicines, or to increase their ability to be spread into the environment. Biological agents can be spread through the air, through water, or in food.  Terrorists may use biological agents because they can be extremely difficult to detect and do not cause illness for several hours to several days.  Some bioterrorism agents, like the smallpox virus, can be spread from person to person and some, like anthrax, cannot.

History

—  In 1984, in The Dalles, Oregon, U.S., a group of extremist followers of Bhagwan Shree Rajneesh (also known as Osho) contaminated the salad in 10 different salad bars with the pathogen of salmonellosis, Salmonella thyphimurium, in order to disable the population.  A total of 751 people contracted the disease and several of them were hospitalized. Although there were no fatalities, this terrorist act is considered the largest bioterrorist attack in the history of the U.S. (Török et al., 1997).

—  In the 1990s, the Japanese cult of Aum Shinrikyo tested different bioweapons, including botulin toxin, anthrax, cholera, and Q fever.  

—  In 1993, during a humanitarian mission in Africa, it tried to obtain samples of the Ebola virus.

—  Between 1990 and 1995, the cult attempted to carry out several bioterrorist acts in Tokyo using vaporized biological agents, including botulinum toxin and anthrax spores. Fortunately, the attacks were unsuccessful (Olson, 1999).

—  A significant bioterrorist event occurred in the U.S. contextually to the dramatic attacks to the World Trade Center in New York in September 2001. The release of Bacillus anthracis spores through the U.S. postal system was carried out with letters addressed to the press and to government officials. There were 22 confirmed cases of anthrax contamination, consisting of 12 cutaneous and 10 inhalational cases. The 12 cutaneous patients responded positively to antibiotic treatment, while of the 10 inhalational cases, 4 were fatal (McCarthy, 2001).

Figure showing Confirmed anthrax cases associated with bioterrorism: U.S., 2001.
A. Geographic location and clinical manifestation of the 11 cases of confirmed inhalational and 7 cases of confirmed cutaneous anthrax.
B. Epidemic curve for the 18 confirmed cases of inhalational and cutaneous anthrax and 4 cases of suspected cutaneous anthrax.

—  In 2002, in Manchester, U.K., six terrorists were arrested for being found in possession of ricin, and in 2004, traces of the same toxin were found at the Dirksen Senate Office Building in Washington D.C. (Bhalla & Warheit, 2004).

—  It appears evident then that the use of biological agents has moved, in recent times, to terrorist groups.

—  This creates very strong concerns that the use of bioweapons by terrorists can create unexpected scenarios characterized by massive destructive potential

Bioterrorism agents’ important features of a perfect BW are:

1. Highly infectious and highly effective.
2. Easily produced with a long shelf life.
3. Efficiently dispersible.
4. Readily grown and produced in large quantities.
5. Stable on storage.
6. Resistant enough to environmental conditions.
7. Resistant to treatment
8. High morbidity and mortality
9. Potential for person-to-person spread
10. Low infective dose and highly infectious by aerosol
11. Lack of rapid diagnostic capability
12. Lack of universally available effective vaccine
13. Potential to cause anxiety
14. Availability of pathogen and feasibility of production
15. Database of prior research and development
16. Potential to be “weaponized”

Category of Bioterrorism by Centers for Disease Control and Prevention (CDC):

The U.S. Centers for Disease Control and Prevention (CDC) defines a bioterrorism attack as “the deliberate release of viruses, bacteria or other germs (agents) used to cause illness or death in people, animals, or plants” (CDC, 2013).  It classifies biological agents into three categories

Category A:

·         The U.S. public health system and primary healthcare providers must be prepared to address various biological agents, including pathogens that are rarely seen in the United States.

·         High-priority agents include organisms that pose a risk to national security because they can be easily disseminated or 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.

Groups	Diseases	Agents
A	Anthrax	Bacillus anthracis
	Botulism	Clostridium botulinum toxin
	Plague	Yersinia pestis
	Smallpox	Variola major
	Tularemia	Francisella tularensis
	Viral hemorrhagic fevers	Filoviruses (e.g. Ebola, Marburg) and Arenaviruses (e.g. Lassa, Machupo)

Category B:

—  Second highest priority agents include those 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.

Groups	Diseases	Agents
B	Brucellosis Epsilon toxin	Brucella spp. Clostridium perfringens
	Food safety threats	Salmonella spp., E.coli O157:H7, Shigella
	Glanders	Burkholderia mallei
	Melioidosis	Burkholderia pseudomallei
	Psittacosis	Chlamydia psittaci
	Q fever	Coxiella burnetii
	Ricin toxin	Ricinus communis
	Staphylococcal enterotoxin B	Staphylococcus spp.
	Typhus fever	Rickettsia prowazekii
	Viral encephalitis	Alphaviruses (e.g. Venezuelan equine encephalitis, Eastern equine encephalitis, Western equine encephalitis
	Water safety threats	Vibrio cholerae, Cryptosporidium parvum

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.

Groups	Diseases	Agents
C	Emerging infectious diseases	Nipahvirus and Hantavirus

Other classifications:

Generally, biological agents (included those used as bioweapons) can be further classified according to certain characteristics that define the hazard to health (NATO, 1996):

a.       Infectivity: The aptitude of an agent to penetrate and multiply in the host.

b.      Pathogenicity: The ability of the agent to cause a disease after penetrating into the body.

c.       Transmissibility: The ability of the agent to be transmitted from an infected individual to a healthy one

d.      Ability to neutralise: Its means to have preventive tools and / or therapeutic purposes.

Transmissions:

Biological agents can be transmitted through one or more ways.  The transmission modes are the following:

1. Parenteral: Agents that are transmitted through body fluids or blood.
2. Airway (by droplets): Agents that are emitted by infected people, which can then be inhaled by surrounding people.
3. Contact: Through which the agents present on the surface of the infected organism can infect another organism.
4. Oral-faecal route: Through objects, foods or other items contaminated with the faeces of infected patients, or through sexual contact.

Impacts of Bioterrorism:

—  Economic impact of a bioterrorism attack could be devastating.

—  Cost $23 million to decontaminate a government building after 2001 anthrax attacks in the US.

—  Early intervention can significantly decrease the costs resulting from a bioterrorist attack.

—  Still expensive to provide prophylactic antibodies to a large number of individuals

—  Reduction in hospital admissions greatly outweighs initial costs

Warning signs:

—  In any location hit by a bioterrorism act the public health system will probably be first to detect and respond.

—  May not be realistic to wait for confirmation of diagnosis.

—  Delay increases the potential for spread.

—  Emergency response may need to be activated on basis of patterns and timing of patient presentation.

—  Important clues that can help alert hospitals to bioterrorist attack

—  Every health care professional should be suspicious of any unusual activity.

—  It will take many people in a variety of fields to control the impact of a biological attack.

—  Veterinarians –many infectious diseases are zoonotic

—  Scientists, epidemiologists, doctors, and nurses will need to work together.

—  Law enforcement –reporting disease and controlling public reaction

—  Bioterrorism is a matter of national and international security.

—  Require the coordination of local, state, federal, and international agencies

Individual role

—  It is imperative that you understand your role.

—  Prepare ahead of time.

—  Become familiar with the location of important telephone numbers and resources.

—  Then you will be ready to assist at a moment’s notice.

—  Your day-to-day responsibilities may be much different during the response to a bioterrorist attack.

—  First step is notifying the proper officials.

—  Know how to contact these agencies in advance.  

—  This may save crucial minutes during a time of chaos.