| Contents | Previous | Next |
While we have spent much space in this course discussing influenza pandemics, we will now examine an even more chilling scenario: that of intentional biological warfare (Bio War). For example, given the relative simplicity of the 1918 pandemic mutation, it is believed that the modern virus could be engineered to incorporate that genome, with other microbial enhancements. Or, as has been historically demonstrated, accidental lab misfortunes, or strange lab-created pandemics not yet visualized could become realities. In this section we will discuss some of the available information on BioWar to date.
Newly emerging and re-emerging infectious diseases coupled with increasing resistance of both pathogens and vectors, pose a risk because of their communicability, and nurses need to be aware of some of the possibilities. Because of recent global events, the threat of biologic warfare has been openly discussed with a newfound realism. Protecting the civilian population is the challenge we face with vaccines, surveillance, and intelligent preparation. The challenge arises with the unknown factors, i.e. biologic agents are not normally public health problems.
Therefore, it is imperative that nurses gain a basic understanding in order to recognize epidemiologic patterns based on surveillance from emergency room visits, lab data, school absenteeism, etc. Communication between departments is essential. If a nurse suspects that an act of bioterrorism has caused a patient’s illness, the public health department, infection control specialist, or hospital epidemiolgoist needs to be contacted immediately.
The September 11th attacks in New York in 2001 are indelibly etched in our minds. Since that date, the danger and reality of terrorist activity against the United States have become very real to all of us. We also know that the threats are not limited to explosive attacks, and we are reminded daily by the media of biological threats, aimed at Americans. We are also reminded that in fact, terrorist may use attacks with biological weapons and pose even greater danger to larger numbers of people.
While the Pentagon struggles to deploy a huge antimissile system against a presumed threat from North Korean rockets, biologists are working to develop tiny “antimicrobial” defenses against harmful germs. The creation and stockpiling of biological weapons was outlawed in 1972, but the danger still persists.
The small amount of agents necessary to kill hundreds of thousands of people in a metropolitan area makes the concealment, transportation, and dissemination of biological agents relatively easy. They cause high mortality and social disruption and thus require special emergency preparation on the part of the health care and public health systems.
Biological agents are easy to acquire, synthesize, and use. BioWar agents are difficult to detect or protect against; they can be invisible, odorless, and tasteless, while their dispersal can be performed silently. There are more than 1200 different kinds of biological agents. Agents include: bacteria, viruses, and their toxins. Others are prions, fungi, parasites, and Rickettsiae. (The Rickettsiae fall between bacteria and viruses and cause typhus and Rocky Mountain Spotted Fever). Biologicals have been called “the poor man’s bomb”. Biological weapons include any organism or toxin found in nature that can be used to incapacitate, kill, or impede a perceived adversary.
Some examples of diseases created by weaponized agents are smallpox, anthrax, avian influenza, botulism, foodborne illness, hantavirus, legionnaires’ disease, molds/fungi, pneumonic plague, smallpox, tularemia, and viral hemorrhagic fevers (VHF’s). Some, such as smallpox or VHFs are highly contagious; others such as anthrax, are unlikely to be spread person to person.
The most potent ones are a core list of 19 bacteria, 43 viruses, 14 toxins, and 4 rickettsiae. We will look at some of those, but obviously to look at all biological agents would require perhaps a year’s worth of study.
Regardless of the cause, natural mutational evolution, accident, or an intentional release, the responsibility for recognition of unusual outbreaks will fall on nurses and physicians. Now is the time to become aware of some potential threats, and to collectively evaluate vulnerabilities and weaknesses in an effort to create a plan. Unpreparedness could become a lethal choice despite the obvious daunting task of preparing for the unknown.
According to the CDC (Centers for Disease Control and Prevention,. Bioterrorism Agents/Diseases, November 19, 2004) the following show the categories of concern:
CATEGORY A
CATEGORY B
CATEGORY C
The Departments of Defense, Homeland Security and Health and Human Services are also interested in antimicrobial research because they want to find better ways to counter the threat of biological terrorism. Dr. Samuel Miller, a biochemist at the University of Washington in Seattle, for example, directs a government-supported ‘Center for Bio-defense and Emerging Diseases’ that studies ways to strengthen human defenses against the flea-borne bacterium that causes plague (among other diseases). “Outbreaks of contagious diseases are nothing new,” Miller said. “What has changed is the approach to seeking countermeasures to infectious diseases, both those arising naturally and those dispersed intentionally.”
In 1953, DNA was first genetically described. By 1973 the cell splicing occurred (recombinant DNA) known as genetic engineering. Today science is moving at lightning speed in the exotic development of genetic engineering now that the human genome project is complete. There is work to map genetic differences based on race for the purpose of ethnic biological weaponry. We are already able to take benign microorganisms and splice a foreign gene into them to alter them, like a potentially bad movie. It is easy to imagine the ability to make lethal bacteria antibiotic resistant while stable in aerosol dispensers.
Today, hundreds of experiments are taking place around the world in which scientists genetically modify viruses and bacteria. In 2002, scientists from the University of New York at Stony Brook made history by using the genetic blueprint of the polio virus as their guide. They downloaded the required sequences from the Internet and stitched these sequences together using well-known splicing techniques. The result was the world’s first totally artificial virus, created not via natural reproduction but via cookbook. This synthetic poliovirus was indistinguishable from its natural cousins and completely viable.
The Stony Brook team started with nothing more than a written copy of the virus’s RNA code, a string of 7,741 molecular “letters” that tell the virus how to function. The first task was to construct a strand of RNA that reflected that written blueprint. But since RNA is relatively unstable in the laboratory, the team first made a DNA version of the virus’s code by ordering customized pieces of DNA from an Iowa-based company that sells made-to-order snippets of genetic material.
The team assembled the molecules into a DNA equivalent of the full-length polio genome, and then used an enzyme that turns DNA into RNA to make a working copy of the poliovirus’s natural RNA core. Assembling the poliovirus showed that eradicating a virus in the wild might not mean it was gone forever because biochemists could now reconstruct those viruses from blueprints. It is possible that viruses like ebola could be assembled in laboratories, but there are only a few people in the world with that skill.
In 2001, Australian researchers tried to create a contraceptive vaccine for mice using mousepox as a transport system; by accident, they created a killer strain of the virus, which wiped out the animals’ immune systems. Other genetic variations could involve plant life known as crop warfare, creating a resistant strain to a virus in one country while infecting another.
These sequences, technically known as oligomers, are easily available in internet databases. These databases are growing exponentially as laboratories around the world isolate and characterize more sequences.
Could the West Nile virus have been released by terrorists? In 1999 there had been reports that Saddam Hussein had threatened to use West Nile virus as a weapon, (The New Killer Diseases, Ellinor Levy and Fischetti, page 105). However, there are other theories. According to (Mclean, in Annals of the New York Academy of Sciences 951, Dec. 2001; 54-57), scientists at a wildlife center deliberately injected crows with West Nile virus, and all of them died. Those not injected, but nearby, also died. It was thought that the virus might have spread via saliva between birds as they peck for food.
In 2002 CDC found that four people might have contracted the virus when they received contaminated organs donated by a car crash victim. Other people became infected from blood transfusions (Morbidity and Mortality Weekly Reports 51 (Dec. 2002): 1129-31.
Scientists at Washington University School of Medicine in St. Louis have become the first to successfully grow a norovirus in the lab on Nov. 30, 2004. As we’ve seen, noroviruses are a highly contagious cause of diarrhea, vomiting, and other stomach upsets that made headlines two years ago after a series of repeated outbreaks on cruise ships. This, too, is spreading.
The replica of the deadly virus Spanish Flu virus is located on the Clifton Road in Atlanta, Georgia, (CDC headquarters) where only a handful of scientists have security clearance to access the laboratory. The numbers of labs with access to deadly infectious agents like anthrax and plague has jumped twenty fold since early 2001, according to Richard Ebright, a molecular biologist at Rutgers University. Scientists who have little or no experience with those pathogens head the vast majority of new labs. “Mathematically,” he says, “you’re going to have an increase in the number of accidents.”
With money being allocated to agencies in attempts to find a bird flu cure, many approaches are being examined today. Among them are those looking at the 1918 Spanish Flu strain and manipulating it today.
The resurrection of the 1918 flu in a federal laboratory proved to be at least 100 times more lethal to mice than other flu strains. A separate group, led by the CDC in Atlanta, used the genetic blueprint to re-create the virus in a lab, and test its potency against other flu strains. The researchers found that the Spanish flu could grow without a key chemical ingredient required by other flu viruses, allowing it to burrow deeply into the lungs with lethal results, especially among young, otherwise healthy people.
There is a question of safety. The worst-case scenario is that researchers might end up engineering extremely dangerous viruses that would never have evolved naturally. Today there are a few new techniques being experimented with. For example, reverse genetics - changing the genome of the bird flu virus to mimic mutations that might occur naturally. Another approach is to mix bird flu genes with those of human flu viruses, either using reverse genetics or through random re-assortment in cells infected with both types.
Although re-assortment sounds more natural, there is a problem. “Re-assortments can be made very easily in the lab using cells or animals,” says flu expert Graeme Laver, formerly at the Australian National University in Canberra. “But one of the big mysteries is that [human] viruses that appear by reassortment are extremely rare in nature. There is something else involved that we don’t understand.”
One can see that with all the experiments going on, the opportunities for accidents, or viruses being stolen for the purpose of creating horrendous harm, are rising. We face yet another aspect in the larger picture of expecting the unexpected from the microbials and new symptoms to be sensitive to.
The use of biological agents is not a new concept and history is amply documented with examples of biological weapon use. Before the 20th century, biological warfare took on 3 main forms:
Archers infected their arrows by dipping them in decomposing bodies or in blood mixed with manure as far back as 400 BC. Persian, Greek, and Roman literature from 300 BC quote examples of the use of animal cadavers to contaminate wells and other sources of water. In 190 BC, Hannibal, at the Battle of Eurymedon, won a naval victory by firing earthen vessels full of venomous snakes into the enemy ships.
In the 18th century AD during the French and Indian War, British forces in North America gave blankets from smallpox patients to the Native Americans to create a transmission of the disease to the immunologically unprotected tribes. During the Civil War (1863), a confederate surgeon was charged with attempting to import yellow fever–infected clothes into the northern parts of the United States.
During World War I, the Germans developed anthrax, glanders, cholera, and a wheat fungus for use as biological weapons. Biological warfare became more sophisticated against both animals and humans during the 1900s. They allegedly spread plague in St Petersburg, infected mules with glanders in Mesopotamia, and attempted to do the same with the horses of the French Calvary.
In World War II, the Japanese operated a secret biological warfare research facility in Manchuria and carried out human experiments on Chinese prisoners. They exposed more than 3000 victims to plague, anthrax, syphilis, and other agents. Victims were observed for development of disease, and autopsies were performed. This was despite the 1925 signature of the Geneva Protocol signed by 108 nations.
Anthrax and botulinum toxin initially were investigated for use as weapons, and sufficient quantities of botulinum toxin and anthrax cattle cakes were stockpiled by June 1944 to allow limited retaliation if the Germans first used biological agents. Japan used plague as a biological weapon against the Chinese during World War II by dropping plague-infected fleas over populated areas and causing outbreaks of the disease.
From 1951-1954, Bacillus globigii and Serratia marcescens were released off both coasts of the United States to demonstrate the vulnerability of American cities to biological agent attacks. The United States continued research on various offensive biological weapons during the 1950s and 1960s.. American stockpiles of biological weapons were destroyed completely by 1973. The United States is a signatory nation of the Biological Toxin Weapons Convention of 1972.
During the Vietnam War, Vietcong guerrillas used punji stakes dipped in feces to increase the morbidity from wounding by these stakes. The Soviet Union (USSR) continued to develop biological weapons from 1950-1980. In the 1970s, the USSR and its allies were suspected of having used ‘yellow rain’ (trichothecene mycotoxins) during campaigns in Loas, Cambodia, and Afghanistan.
Since the 1980s, terrorist organizations have become users of biological agents. The most frequent bioterrorism episodes have involved contamination of food and water. In September and October of 1984, 751 persons were infected with Salmonella typhimurium after an intentional contamination of restaurant salad bars in Oregon by followers of the Bhagwan Shree Rajneesh. (This writer visited the town where the Bhagwan Shree Rajneesh lived in Oregon prior to the intentional release of Salmonella typhimurium)
The Russians denied responsibility for the accident in 1979 when a release of anthrax from a weapons facility in Sverdlovsk, USSR, killed at least 66 people. They finally admitted it in 1992.
Iraq began an offensive biological weapons program producing anthrax, botulinum toxin, and aflatoxin in 1985. The coalition of allied forces faced the threat of chemical and biological agents during Operation Desert Shield. Following the Persian Gulf War, Iraq disclosed that it had bombs, Scud missiles, 122-mm rockets, and artillery shells armed with botulinum toxin, anthrax, and more.
Today, 17 countries are suspected of having an offensive BioWar program. In 1994, a Japanese sect attempted an aerosolized release of anthrax from the tops of buildings in Tokyo. In 1995, 2 members of a Minnesota militia group were convicted of possession of ricin, which they had produced themselves for use in retaliation against local government officials. In 1996, an Ohio man was able to obtain bubonic plague cultures through the mail.
The Defense Against Weapons of Mass Destruction Act in 1997 directed the Department of Defense to establish a domestic preparedness program to improve the ability of local, state, and federal agencies to respond to biological incidents.
A total of 23 confirmed or suspected cases of bioterrorism-related anthrax from September to November 2001 occurred in the United States. As a result of these cases, approximately 32,000 persons with potential exposures initiated antibiotic prophylaxis to prevent anthrax infections. Consider the potential impact to the immune system by taking medications on a prophylactic basis.
There are challenges to creating a bioterror assault. For example, the use of an explosive device to deliver and disseminate biological agents is not very effective, since such agents tend to be inactivated by the blast. A contamination of a municipal water supply requires an unrealistically large amount of agent and introduction into the water after it passes through a regional treatment facility.
To be an effective biological weapon, airborne pathogens must be dispersed as fine particles less than 5 mm in size. Infection with an aerosolized agent usually requires deep inspiration of an infectious dose. Low-technology aerosolization methods including agricultural crop-dusters; aerosol generators on small boats, trucks, or cars; backpack sprayers; and even purse-size perfume atomizers suffice. Aerosolized dispersal of biological agents is the mode most likely to be used by terrorists and military groups.
Early detection of a biological agent in the environment allows for early specific treatment and time during which prophylaxis would be effective. The US Department of Defense has placed a high priority on research and development of detector systems.
Nurses and physicians must be able to identify early victims and recognize patterns of disease. This requires integrated epidemiologic surveillance systems performing real-time monitoring with information shared at many levels of the health care system. Many community hospitals have started communicating with public health agencies to create a surveillance system.
Protective measures can be taken against BW agents. These should be implemented early (if warning is received) or later (once suspicion of BW agent use is made). Currently, available masks such as the military gas mask or high-efficiency particulate air (HEPA) filter masks used for tuberculosis (TB) exposure filter out most BW particles delivered by aerosol. Multilayered HEPA masks can filter 99.9% of 1- to 5-mm particles, but face-seal leaks may reduce the efficacy by as much as 10-20%. Individual face-fit testing is required to correct seal leak problems.
After an aerosol attack, simple removal of clothing eliminates a great majority of surface contamination. Most aerosolized biological agents do not penetrate unbroken skin, and few organisms adhere to skin or clothing. Thorough showering with soap and water removes 99.99% of the few organisms left on the victim’s skin after disrobing. The use of sodium hypochlorite is not recommended over soap and water.
Normal clothing provides a reasonable degree of protection against dermal exposure. Latex gloves and universal precautions provide sufficient protection when treating most infected patients. Patients may be placed in a private negative-pressure room with universal precautions. Proper disposal of corpses is essential. In the case of anthrax spores, this should be performed by incineration.
Biosafety Level 1 is suitable for work involving well-characterized agents not known to consistently cause disease in healthy adult humans, and of minimal potential hazard to laboratory personnel and the environment. The laboratory is not necessarily separated from the general traffic patterns in the building. Work is generally conducted on open bench tops using standard microbiological practices. Special containment equipment or facility design is neither required nor generally used.
Biosafety Level 2 is similar to Biosafety Level 1 and is suitable for work involving agents of moderate potential hazard to personnel and the environment. It differs from BSL 1 in that:
Biosafety Level 3 is applicable to clinical, diagnostic, teaching, research, or production facilities in which work is done with indigenous or exotic agents that may cause serious or potentially lethal disease as a result of exposure by the inhalation route.
Laboratory personnel have specific training in handling pathogenic and potentially lethal agents, and are supervised by competent scientists who are experienced in working with these agents. Personnel wearing appropriate personal protective clothing and equipment conduct within biological safety cabinets or other physical containment devices, or all procedures involving the manipulation of infectious materials. The laboratory has special engineering and design features.
It is recognized, however, that some existing facilities may not have all the facility features recommended for Biosafety Level 3 (i.e., double-door access zone and sealed penetrations). In this circumstance, an acceptable level of safety for the conduct of routine procedures, (e.g., diagnostic procedures involving the propagation of an agent for identification, typing, susceptibility testing, etc.), may be achieved in a Biosafety Level 2 facility, providing:
Biosafety Level 4 is required for work with dangerous and exotic agents that pose a high individual risk of aerosol-transmitted laboratory infections and life-threatening disease. Agents with a close or identical antigenic relationship to Biosafety Level 4 agents are handled at this level until sufficient data are obtained either to confirm continued work at this level, or to work with them at a lower level.
Members of the laboratory staff have specific and thorough training in handling extremely hazardous infectious agents and they understand the primary and secondary containment functions of the standard and special practices, the containment equipment, and the laboratory design characteristics. Competent scientists who are trained and experienced in working with these agents supervise them. The laboratory director strictly controls access to the laboratory.
The facility is either in a separate building or in a controlled area within a building, which is completely isolated from all other areas of the building. A specific facility operations manual is prepared or adopted. Within work areas of the facility, all activities are confined to Class III biological safety cabinets, or Class II biological safety cabinets used with one-piece positive pressure personnel suits ventilated by a life support system. The Biosafety Level 4 laboratory has special engineering and design features to prevent microorganisms from being disseminated into the environment.
The United states has at least 7 BSL 4 facilities located in Fort Dietrich, MD, Atlanta GA, Bethesda MD, San Antonio, TX, Galveston TX, Long Island NY (Plum Island), Hamilton, MT. Winnipeg in Canada has at least one BSL 4 facility, located in the Government of Canada laboratories. Lyon France has 4, BSL 4.
Newly emerging and re-emerging infectious diseases coupled with increasing resistance of both pathogens and vectors, pose a risk because of their communicability and nurses need to be aware of some of the possibilities. Because of recent global events, the threat of biologic warfare (BioWar) has been openly discussed with a newfound realism. Protecting the civilian population is the challenge we face with vaccines, surveillance, and intelligent preparation. The challenge arises with the unknown factors, i.e. biologic agents are not normally public health problems.
In the 1950’s Plum Island Research Lab (close to New York City) was established. The research involved tick colonies and biological experimentation. Some people claim that it was the birthplace of Lyme Disease. Accidents happen. (Carroll, Michael, Lab 257, 2004).
Today we already are able to take benign microorganisms and splice a foreign gene into them in order to alter them. It is easy to imagine the ability to make lethal bacteria antibiotic resistant while stable in aerosol dispensers. Creating horrific scenarios is not difficult, and not impossible to actualize if in the wrong hands.
Nurses and physicians must be able to identify early victims and recognize patterns of disease. This requires integrated epidemiologic surveillance systems performing real-time monitoring with information shared at many levels of the health care system.