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- Herausgeber: Madison & Adams Press
- Kategorie: Fachliteratur
- Sprache: Englisch
- Veröffentlichungsjahr: 2017
The purpose of this book is to provide concise supplemental reading material to assist both, health-care providers and civilians in the management of biological casualties. The main goal is to make this a reference for all those who need basic summary and treatment information quickly. Table of Contents: History of Biological Warfare and Current Threat Distinguishing Between Natural and International Disease Outbreaks Ten Steps in the Management of Biological Casualties Therapy Case Reporting and Epidemiological Assessment Prevention Protective Equipment First Aid Protective Measures and Handling of Causalities Patient Decontamination Infection Control Medical Evacuation Aeromedical Isolation Team Bacterial Agents: Anthrax Brucellosis Plague Q Fever Tularemia Viral Agents: Smallpox Venezuelan Equine Encephalitis Biological Toxins: Botulinum Ricin Staphylococcal Enterotoxin B T-2 Mycotoxins Glossary of Medical Terms Patient Isolation Precautions BW Agent Characteristics BW Agent Vaccines, Prophylactics and Therapeutics Differential Diagnosis Comparative Lethality Emergency Response Contacts
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Biological Warfare
INTRODUCTION
Medical defense against the use of biological pathogens and toxins as weapons of warfare or terrorism is an area of study previously unfamiliar to many health-care providers. The U.S. military has maintained an ongoing research agenda against biological weapon threats since World War II, but the terrorist attacks on the U.S. mainland in September 2001 and the anthrax mail attacks in October 2001 provided a wake-up call for lawmakers, the public at large, and medical providers of all backgrounds that the threat of biological attacks was real and required planning, training, and resources for response. Consequently, there has been an explosion of interest among health-care practitioners to understand better how to manage the medical consequences of exposure to biological weapons that can lead to mass casualties.
Numerous measures to improve preparedness for and response to biological warfare (BW) or terrorism are ongoing at local, state, and federal levels. Training efforts have increased in both military and civilian sectors. A week-long Medical Management of Chemical and Biological Casualties Course taught at both USAMRIID and USAMRICD trains over 560 military medical professionals each year on biological and chemical medical defense. The highly successful USAMRIID international satellite courses on the Medical Management of Biological Casualties have reached over 110,000 medical personnel since 1997.
Through this handbook and courses noted above, medical professionals learn that effective medical countermeasures are available against many of the bacteria, viruses, and toxins that might be used as biological weapons against our military forces or civilian communities. The importance of this education cannot be overemphasized and it is hoped that health-care professionals will develop a solid understanding of the biological threats we face and the effective medical defenses against these threats.
The global BW threat is serious, and the potential for devastating casualties is high for certain biological agents. There are more than 10 countries around the world suspected to have offensive biological weapons programs. However, with early recognition, intervention, and appropriate use of medical countermeasures either already developed or under development, many casualties can be prevented or minimized.
Even if providers have not read the text thoroughly, the purpose of this handbook is to serve as a concise pocket-sized manual that can be pulled off the shelf (or from a pocket) in a crisis to guide medical personnel in the prophylaxis and management of biological casualties. It is designed as a quick reference and overview, and is not intended as a definitive text on the medical management of biological casualties. More in-depth discussion of the agents covered here may be found in infectious diseases, tropical medicine, and disaster management textbooks.
HISTORY OF BIOLOGICAL WARFARE AND CURRENT THREAT
The use of biological weapons in warfare has been recorded throughout history. During the 12th –15th centuries BC the Hittites are known to have driven diseased animals and people into enemy territory with the intent of initiating an epidemic. In the 6th century BC, the Assyrians poisoned enemy wells with rye ergot, and Solon used the herb hellebore to poison the water source of the city of Krissa during his siege. In 1346, plague broke out in the Tartar army during its siege of Kaffa (at present day Feodosia in Crimea). The attackers hurled the corpses of plague victims over the city walls; the epidemic that followed forced the defenders to surrender, and some infected people who left Kaffa may have started the Black Death pandemic, which spread throughout Europe and is believed to have resulted in the death of one-third of the population of Europe – as many as 25 million people. Russian troops may have used the same tactic against the Swedes in 1710.
On several occasions throughout history, smallpox was used as a biological weapon. Pizarro is said to have presented South American natives with variola virus-contaminated clothing in the 15th century, and the English did the same when Sir Jeffery Amherst ordered his troops to provide Indians loyal to the French with smallpox-laden blankets in 1763 towards the close of the French and Indian Wars. Native Americans defending Fort Carillon sustained epidemic casualties, which directly contributed to the loss of the fort to the English. General George Washington ordered variolation (an early form of smallpox vaccination) for the Continental Army in 1777 after the loss of the siege of Quebec, in part due to devastation rendered on his forces by smallpox, and because of the potential for purposeful spread of smallpox among the colonials by the British.
Use of biological weapons continued into the 1900s; however, the stakes became higher as the science of microbiology allowed for a new level of sophistication in producing agents. There is evidence that during World War I, German agents inoculated horses and cattle with anthrax and glanders at the Port of Baltimore before the animals were shipped to France. In 1937, Japan started an ambitious biological warfare (BW) program, located 40 miles south of Harbin, Manchuria, code-named “Unit 731.” Studies directed by Japanese general and physician Shiro Ishii continued there until it was destroyed in 1945. A post-World War II investigation revealed that the Japanese researched numerous organisms and used prisoners of war as research subjects. About 1,000 human autopsies apparently were carried out at Unit 731, mostly on victims exposed to aerosolized anthrax. Many more prisoners and Chinese nationals may have died in this facility - some have estimated up to 3,000 human deaths. The Japanese also apparently used biological agents in the field: after reported overflights by Japanese planes suspected of dropping plague-infected fleas, plague epidemics ensued in China and Manchuria. By 1945, the Japanese program had stockpiled 400 kilograms of anthrax to be used in a specially designed fragmentation bomb.
In 1943, the U.S. began its own research and development program in the use of biological agents for offensive purposes. Similar programs existed in Canada, the United Kingdom (UK), and probably several other countries. This work was started, interestingly enough, in response to a perceived German BW threat as opposed to a Japanese one. The U.S. research program was headquartered at Camp Detrick (now Fort Detrick), which was a small National Guard airfield before that time, and produced agents and conducted field testing at other sites until 1969, when President Nixon stopped all offensive biological and toxin weapon research and production by executive order. Between May 1971 and May 1972, all stockpiles of biological agents and munitions from the now defunct U.S. program were destroyed in the presence of monitors representing the U.S. Department of Agriculture, the Department of Health, Education, and Welfare, (now Health and Human Services), and the states of Arkansas, Colorado, and Maryland. Included among the destroyed agents were Bacillus anthracis, botulinum toxin, Francisella tularensis, Coxiella burnetii, Venezuelan equine encephalitis virus, Brucella suis, and staphylococcal enterotoxin B. The U.S. began a medical defensive program in 1953 that continues today at USAMRIID.
In 1972, the U.S., UK, and USSR signed the Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on Their Destruction, commonly called the Biological Weapons Convention. Over 140 countries have since added their ratification. This treaty prohibits the stockpiling of biological agents for offensive military purposes, and also forbids research on agents for other than peaceful purposes. To strengthen efforts to combat the BW threat, signatory states agreed in November 2002 to have experts meet annually through 2006 to discuss and promote common understanding and effective action on biosecurity, national implementation measures, suspicious outbreaks of disease, disease surveillance, and codes of conduct for scientists. However, despite this historic agreement among nations, BW research continued to flourish in many countries hostile to the U.S. Moreover, there have been several cases of suspected or actual use of biological weapons. Among the most notorious of these were the “yellow rain” incidents in Southeast Asia, the use of ricin as an assassination weapon in London in 1978, and the accidental release of anthrax spores at Sverdlovsk in 1979.
Testimony from the late 1970s indicated that Laos and Kampuchea were attacked by planes and helicopters delivering colored aerosols. After being exposed, people and animals became disoriented and ill, and a small percentage of those stricken died. Some of these clouds were thought to be comprised of trichothecene toxins (in particular, T2 mycotoxin). These attacks are grouped under the label “yellow rain.” There has been a great deal of controversy about whether these clouds were truly BW agents. Some have argued that the clouds were nothing more than feces produced by swarms of bees.
In 1978, a Bulgarian exile named Georgi Markov was attacked in London with a device disguised as an umbrella, which injected a tiny pellet filled with ricin toxin into the subcutaneous tissue of his leg while he was waiting for a bus. He died several days later. On autopsy, the tiny pellet was found and determined to contain ricin toxin. It was later revealed that the Bulgarian secret service carried out the assassination, and the technology to commit the crime was supplied by the former Soviet Union.
In April, 1979, an incident occurred in Sverdlovsk (now Yekaterinburg) in the former Soviet Union which appeared to be an accidental aerosol release of Bacillus anthracis spores from a Soviet military microbiology facility: Compound 19. Residents living downwind from this compound developed high fever and had difficulty breathing; a large number died. The Soviet Ministry of Health blamed the deaths on the consumption of contaminated meat, and for years controversy raged in the press over the actual cause of the outbreak. All evidence available to the United States government indicated a release of aerosolized B. anthracis spores. In the summer of 1992, U.S. intelligence officials were proven correct when the new Russian President, Boris Yeltsin, acknowledged that the Sverdlovsk incident was in fact related to military developments at the microbiology facility. In 1994, Meselson and colleagues published an in-depth analysis of the Sverdlovsk incident. They documented that all of the cases from 1979 occurred within a narrow zone extending 4 kilometers downwind in a southerly direction from Compound 19. There were at least 66 fatalities in the 77 patients identified.
In August, 1991, the U.N. carried out its first inspection of Iraq’s BW capabilities in the aftermath of the Gulf War. On August 2, 1991, representatives of the Iraqi government announced to leaders of U.N. Special Commission Team 7 that they had conducted research into the offensive use of B. anthracis, botulinum toxins, and Clostridium perfringens (presumably one of its toxins). This open admission of biological weapons research verified many of the concerns of the U.S. intelligence community. Iraq had extensive and redundant research facilities at Salman Pak and other sites, many of which were destroyed during the war.
In 1995, further information on Iraq’s offensive program was made available to United Nations inspectors. Iraq conducted research and development work on anthrax, botulinum toxins, Clostridium perfringens, aflatoxins, wheat cover smut, and ricin. Field trials were conducted with B. subtilis (a simulant for anthrax), botulinum toxin, and aflatoxin. Biological agents were tested in various delivery systems, including rockets, aerial bombs, and spray tanks. In December 1990, the Iraqis filled 100 R400 bombs with botulinum toxin, 50 with anthrax, and 16 with aflatoxin. In addition, 13 Al Hussein (SCUD) warheads were filled with botulinum toxin, 10 with anthrax, and 2 with aflatoxin. These weapons were deployed in January 1991 to four locations. In all, Iraq produced 19,000 liters of concentrated botulinum toxin (nearly 10,000 liters filled into munitions), 8,500 liters of concentrated anthrax (6,500 liters filled into munitions) and 2,200 liters of aflatoxin (1,580 liters filled into munitions). The extent of Iraq’s biological weapons program between 1998 when UNSCOM left Iraq and the U.S. coalition invasion in March 2003 remains unknown. Current information indicates the discovery of a clandestine network of biological laboratories operated by the Iraqi Intelligence Service (Mukhabarat), a prison laboratory complex possibly used for human experimentation, an Iraqi scientist’s private culture collection with a strain of possible BW interest, and new research activities involving Brucella and Crimean-Congo hemorrhagic fever virus.
The threat of BW has increased in the last two decades, with a number of countries working on the offensive use of these agents. The extensive program of the former Soviet Union is now primarily under the control of Russia. Former Russian president Boris Yeltsin stated that he would put an end to further offensive biological research; however, the degree to which the program was scaled back is not known. Revelations from Ken Alibek, a senior BW program manager who defected from Russia in 1992, outlined a remarkably robust BW program, which included active research into genetic engineering, binary biologicals and chimeras, and capacity to produce industrial quantities of agents. There is also growing concern that the smallpox virus, lawfully stored in only two laboratories at the Centers for Disease Control and Prevention (CDC) in Atlanta and the Russian State Centre for Research on Virology and Biotechnology, may be in other countries around the globe.
There is intense concern in the west about the possibility of proliferation or enhancement of offensive programs in countries hostile to the western democracies, due to the potential hiring of expatriate Russian scientists. Iraq, Iran, and Syria have been identified as countries “aggressively seeking” nuclear, biological, and chemical weapons. Libya was also included; however, Libya has recently renounced further pursuit of offensive programs.
The 1990s saw a well-placed increasing concern over the possibility of the terrorist use of biological agents to threaten either military or civilian populations. Extremist groups have tried to obtain microorganisms that could be used as biological weapons. The 1995 sarin nerve agent attack in the Tokyo subway system raised awareness that terrorist organizations could potentially acquire or develop weapons of mass destruction (WMD) for use against civilian populations. Subsequent investigations revealed that, on several occasions, the Aum Shinrikyo had released botulinum toxin (1993 and 1995) and anthrax (1995) from trucks and rooftops. Fortunately, these efforts were unsuccessful. The Department of Defense initially led a federal effort to train the first responders in 120 American cities to be prepared to act in case of a domestic terrorist incident involving WMD. This program was subsequently handed over to the Department of Justice in 2000. First responders, public health and medical personnel, and law enforcement agencies have dealt with the exponential increase in biological weapons hoaxes around the country over the past several years.
The events of September 11, 2001, and subsequent anthrax mail attacks brought immediacy to planning for the terrorist use of WMD in the U.S.. Anthraxladen letters placed in the mail caused 23 probable or confirmed cases of anthrax-related illness and five deaths, mostly among postal workers and those handling mail. On October 17, 2001, U.S. lawmakers were directly affected by anthrax contamination leading to closure of the Hart Senate Office Building in Washington, D.C. Terrorist plots to use ricin were uncovered in England in January, 2003. Ricin was also found in a South Carolina postal facility in October, 2003 and the Dirksen Senate Office Building in Washington, D.C. in February, 2004.
The National Strategy for Homeland Security and the Homeland Security Act of 2002 were developed in response to the terrorist attacks. The Department of Homeland Security (DHS), with over 180,000 personnel, was established to provide the unifying foundation for a national network of organizations and institutions involved in efforts to secure the nation. Over $8 billion from the DHS has been awarded since March, 2003 to help first responders and state and local governments to prevent, respond to and recover from potential acts of terrorism and other disasters. The Office for Domestic Preparedness (ODP) is the principal component of the DHS responsible for preparing the U.S. for acts of terrorism by providing training, funds for the purchase of equipment, support for the planning and execution of exercises, technical assistance and other support to assist states and local jurisdictions to prevent, plan for, and respond to acts of terrorism.
The Public Health Security and Bioterrorism Response Act of 2002 requires drinking water facilities to conduct vulnerability assessments; all universities and laboratories that work with biological material that could pose a public-health threat have to be registered with the U.S. Department of Health and Human Services or the U.S. Department of Agriculture; and new steps were imposed to limit access to various biological threat agents. Smallpox preparedness was implemented, including a civilian vaccination program, vaccine injury compensation program, and aid to the States. Prior to the March 2003 invasion of Iraq, state and local health departments and hospitals nationwide conducted smallpox immunizations of healthcare workers and have since prepared statewide bioterrorism response plans.
The threat of the use of biological weapons against U.S. military forces and civilians is more acute than at any time in U.S. history, due to the widespread availability of agents, widespread knowledge of production methodologies, and potential dissemination devices. Therefore, awareness of and preparedness for this threat will require the education of our government officials, health-care providers, public health officials, and law enforcement personnel and is vital to our national security.
DISTINGUISHING BETWEEN NATURAL AND INTENTIONAL DISEASE OUTBREAKS
Determining who is at risk and making appropriate decisions regarding prophylaxis as well as other response measures after a biological weapon attack, whether in a civilian setting as bioterrorism or on the battlefield as biological warfare (BW), will require the tools of epidemiology. With a covert attack, the most likely first indicator of an event will be an increased number of patients presenting to individual care providers or emergency departments with clinical features caused by the disseminated disease agent. The possibility exists that the recognizing authority for something unusual may be other medical professionals, such as pharmacists or laboratorians, who may receive more than the usual numbers of prescriptions or requests for laboratory tests from a number of different care providers. Because animals may be sentinels of disease in humans and many of the high-threat BW agents discussed in this book are zoonoses, it is also possible that veterinarians might recognize an event in animals before it is recognized in humans.
A sound epidemiologic investigation of a disease outbreak, whether natural or human-engineered, will assist medical personnel in identifying the pathogen and lead to the institution of appropriate medical interventions. Identifying the affected population, possible routes of exposure, signs and symptoms of disease, along with rapid laboratory identification of the causative agents, will greatly increase the ability to institute an appropriate medical and public health response. Good epidemiologic information can guide the appropriate follow-up of those potentially exposed, as well as assist in risk communication and responses to the media.
Many diseases caused by weaponized biological agents present with nonspecific clinical features that may be difficult to diagnose and recognize as a biological attack. Features of the epidemic may be important in differentiating between a natural and a terrorist or warfare attack. Epidemiologic clues that may indicate an intentional attack are listed in Table 1. While a helpful guide, it is important to remember that naturally occurring epidemics may have one or more of these characteristics and a biological attack may have none. However, if many of the listed clues are recognized, one’s index of suspicion for an intentionally spread outbreak should increase.
Once a biological attack or any outbreak of disease is suspected, the epidemiologic investigation should begin. Although, the conduct of the investigation will not differ significantly whether the outbreak is intentional or not, there are some important differences. Because the use of a biological weapon is a criminal act, it will be very important for the evidence gathered to be able to stand up to scrutiny in court. Therefore, samples must be handled through a chain of custody and there must be good communication and information sharing between public health and law-enforcement authorities. In addition, because the attack is intentional, one must be prepared for the unexpected – there is the possibility of multiple outbreaks at different locations as well as the use of multiple different agents, including mixed chemical and biological agents or multiple biological agents depending upon the intentions of the perpetrator.
The first step in the investigation is to confirm that a disease outbreak has occurred. Because an outbreak generally means there is a higher rate of an illness than is normally seen in a specific population, then it is helpful to have background surveillance data to determine whether what is being seen constitutes a deviation from the norm. For example, in mid-winter, thousands of cases of influenza may not be considered an outbreak, whereas in the summer, it might be highly unusual. In addition, even a single case of a very unusual illness, such as inhalation anthrax, might constitute an outbreak and should be viewed with suspicion. The clinical features seen in the initial cases can be used to construct a case definition to determine the number of cases and the attack rate [the population that is ill or meets the case definition divided by the population at risk]. The case definition allows investigators who are separated geographically to use the same criteria when evaluating the outbreak. The use of objective criteria in the case definition is critical to determining an accurate case number, as additional cases may be found and some cases may be excluded, especially as the potential exists for hysteria and subjective complaints to be confused with actual disease.
Once the attack rate has been determined, the outbreak can be described by time, place, and person. These data will provide crucial information in determining the potential source of the outbreak. The epidemic curve is calculated based upon cases over time. In a point-source outbreak, which is most likely in a biological attack or terrorism situation, individuals are exposed to the disease agent in a fairly short time frame. The early parts of the epidemic curve may be compressed compared to a natural disease outbreak. In addition, the incubation period could be shorter than what is seen with a natural outbreak if individuals are exposed to higher inoculums of the agent than would occur in the natural setting. The peak may occur in days or even hours. Later phases of the curve may also help determine if the disease is able to spread from person to person. Determining whether the disease is contagious will be extremely important for determining effective disease control measures.
Once the disease is recognized, appropriate prophylaxis, treatment, and other measures to decrease disease spread, such as isolation (if needed for a contagious illness) would be instituted. The ultimate test of whether control measures are effective is whether they reduce ongoing illness or spread of disease.
Before any event, public health authorities must implement surveillance systems so they can recognize patterns of nonspecific syndromes that could indicate the early manifestations of a BW attack. The system must be timely, sensitive, specific, and practical. To recognize any unusual changes in disease occurrence, surveillance of background disease activity should be ongoing, and any variation should be followed up promptly with a directed examination of the facts regarding the change. In the past several years, many public health authorities around the country have initiated such syndrome-based surveillance systems in an attempt to achieve near real-time detection of unusual events.
In summary, it is important to understand that the recognition of and preparation for a biological attack will be similar to that for any infectious disease outbreak, but the surveillance, response, and other demands on resources will likely be of an unparalleled intensity. Public anxiety will be greater after an intentionally caused event; therefore, a sound risk-communication plan that involves public health authorities will be vital to an effective response and to allay the fears of the public. A strong public-health infrastructure with an effective epidemiologic investigating capability, practical training programs, and preparedness plans are essential to prevent and control disease outbreaks, whether they are naturally occurring or intentional.
Table 1. Epidemiologic Clues of a BW or Terrorist Attack
• The presence of a large epidemic with a similar disease or syndrome, especially in a discrete population
• Many cases of unexplained diseases or deaths
• More severe disease than is usually expected for a specific pathogen or failure to respond to standard therapy
• Unusual routes of exposure for a pathogen, such as the inhalational route for diseases that normally occur through other exposures
• A disease that is unusual for a given geographic area or transmission season
• Disease normally transmitted by a vector that is not present in the local area
• Multiple simultaneous or serial epidemics of different diseases in the same population
• A single case of disease by an uncommon agent (smallpox, some viral hemorrhagic fevers, inhalational anthrax, pneumonic plague)
• A disease that is unusual for an age group
• Unusual strains or variants of organisms or antimicrobial resistance patterns different from those known to be circulating
• A similar or exact genetic type among agents isolated from distinct sources at different times and or locations
• Higher attack rates among those exposed in certain areas, such as inside a building if released indoors, or lower rates in those inside a sealed building if released outside
• Disease outbreaks of the same illness occurring in noncontiguous areas
• A disease outbreak with zoonotic impact
• Intelligence of a potential attack, claims by a terrorist or aggressor of a release, and discovery of munitions, tampering, or other potential vehicle of spread (spray device, contaminated letter)
TEN STEPS IN THE MANAGEMENT OF BIOLOGICAL CASUALTIES ON THE BATTLEFIELD
Military medical personnel will require a firm understanding of certain key elements of biological defense to manage effectively the consequences of a biological attack amidst the confusion expected on the modern battlefield. Civilian providers who might be called upon to respond to a terrorist attack require a similar understanding. Familiarity with the behavior, pathogenesis, modes of transmission, diagnostic modalities, and available treatment options for each of the potential agents thus becomes imperative. Acquiring such an understanding is relatively straightforward once the identity of the agent is known; many references, including this handbook, exist to assist medical personnel in agent-based therapy. A larger problem presents itself when the identity of a causative agent is unknown. In some cases, an attack may be threatened, but it may remain unclear as to whether such an attack has actually occurred. Similarly, it may be unclear whether casualties are due to the intentional release of a biological agent or a chemical agent, or whether they are due to a naturally occurring infectious disease outbreak or an accidental toxic industrial exposure. We recommend here a ten-step process to guide medical personnel in the evaluation and management of outbreaks of unknown origin and etiology. We feel that such an algorithmic approach (as exemplified by the Advanced Trauma Life Support Course (ATLS) sponsored by the American College of Surgeons) is desirable and will be helpful when dealing with the unknown, especially under the austere conditions and chaos expected on the modern battlefield.
I. Maintain an index of suspicion. In the case of chemical or conventional warfare and terrorism, the sinister nature of an attack might be obvious. Victims would likely succumb in close temporal and geographic proximity to a dispersal or explosive device. Complicating discovery of the sinister nature of a biological attack, however, is the fact that biological agents possess inherent incubation periods. These incubation periods, typically days to even weeks long, permit the wide dispersion of victims (in both time and space). Moreover, they make it likely that the ‘first responder’ to a biological attack would not be the traditional first responder (fire, police, and paramedical personnel), but rather medics, primary care physicians, emergency room personnel, and public health officials. In such circumstances, the maintenance of a healthy ‘index of suspicion’ is imperative.
Additionally, with many of the biological warfare (BW) diseases, very early treatment is mandatory if patients are to be successfully treated. Anthrax, botulism, plague, and smallpox are readily prevented if patients are provided proper antibiotics, antisera, and/or vaccination promptly after exposure. Conversely, all of these diseases may prove fatal if therapy or prophylaxis is delayed until classic symptoms develop. Unfortunately, symptoms in the early, or prodromal, phase of illness are non-specific, making diagnosis difficult. Moreover, many potential BW diseases, such as brucellosis, Q-fever, and Venezuelan equine encephalitis (VEE), may present simply as undifferentiated febrile illnesses. Without a high index of suspicion, it is unlikely that medical personnel, especially at lower echelons of care, removed from sophisticated laboratory and preventive medicine resources, will promptly arrive at a proper diagnosis and institute appropriate therapy.
II. Protect yourself. Before medical personnel approach a potential biological casualty, they must first take steps to protect themselves. These steps may involve a combination of physical, chemical, and immunologic forms of protection. On the battlefield, physical protection typically consists of a protective mask. Designed primarily with chemical vapor hazards in mind, the M-40 series mask certainly provides adequate protection against all aerosolized BW threats. In fact, a HEPA-filter (or even a simple surgical) mask will often afford adequate protection against biological agents, although not against chemical threats. Chemical protection refers, in general, to the pre- and/or post-exposure administration of antibiotics; such strategies are discussed on an agent-specific basis elsewhere in this book. Immunologic protection principally involves active vaccination and, in the present climate, applies mainly to protection against anthrax and smallpox. Again, specific vaccination strategies are discussed throughout this book.
III. Assess the patient. This initial assessment is somewhat analogous to the primary survey of ATLS management. As such, airway adequacy should be assessed and breathing and circulation problems addressed before attention is given to specific management. The initial assessment is conducted before decontamination is accomplished and should thus be brief, but the need for decontamination and for the administration of antidotes for rapid-acting chemical agents (nerve agents and cyanide) should be determined at this time. Historical information of potential interest to the clinician should also be gathered, and might include information about illnesses among other unit members, the presence of unusual munitions, food and water procurement sources, vector exposure, vaccination history, travel history, occupational duties, and MOPP status. Physical exam at this point should concentrate on the pulmonary and neuromuscular systems, as well as unusual dermatologic and vascular findings.
IV. Decontaminate as appropriate. Decontamination plays a very important role in the approach to chemical casualty management. The incubation period of biological agents, however, makes it unlikely that victims of a BW attack will present for medical care until days after an attack. At this point, the need for decontamination is minimal or non-existent. In those rare cases where decontamination is warranted, simple soap and water bathing will usually suffice. Certainly, standard military decontamination solutions (such as hypochlorite), typically employed in cases of chemical agent contamination, will be effective against all biological agents. In fact, even 0.1% bleach reliably kills anthrax spores, the hardiest of biological agents. Routine use of caustic substances, especially on human skin, however, is rarely warranted after a biological attack. More information on decontamination is included elsewhere in this text.
V. Establish a diagnosis. With decontamination (where warranted) accomplished, a more thorough attempt to establish a diagnosis can be carried out. This attempt, somewhat analogous to the secondary survey used in the ATLS approach, should involve a combination of clinical, epidemiological, and laboratory examinations. The amount of expertise and support available to the clinician will vary at each echelon of care. At higher echelons, a full range of laboratory capabilities might enable prompt definitive diagnoses. At lower echelons, every attempt should be made to obtain diagnostic specimens from representative patients and forward these through laboratory channels. Nasal swabs (important for culture and polymerase chain reaction (PCR), even if the clinician is unsure which organisms are present), blood cultures, serum, sputum cultures, blood and urine for toxin analysis, throat swabs, and environmental samples should be obtained.
While awaiting laboratory confirmation, a physician must attempt to clinically diagnose the infection. Access at higher echelons to infectious disease, preventive medicine, and other specialists, can assist in this process. At lower echelons, the clinician should, at the very least, be familiar with the concept of syndromic diagnosis. Chemical and BW diseases can be generally divided into those that present “immediately” with little or no incubation or have latent periods (principally the chemical agents) and those with a considerable delay in presentation (principally the biological agents). Moreover, BW diseases are likely to present as one of a limited number of clinical syndromes. Plague, tularemia, and staphylococcal enterotoxin (SEB) disease all may present as pneumonia. Botulism and VEE may present with peripheral and central neuromuscular findings, respectively. This allows the construction of a simple diagnostic matrix as shown in Table 1. Even syndromic diagnosis, however, is complicated by the fact that many BW diseases (VEE, Q-fever, brucellosis) may present simply as undifferentiated febrile illnesses. Moreover, other diseases (anthrax, plague, tularemia, smallpox) have undifferentiated febrile prodromes.
VI. Render prompt treatment. Unfortunately, it is precisely in the prodromal phase of many diseases that therapy is most likely to be effective. For this reason, empiric therapy of pneumonia or undifferentiated febrile illness on the battlefield might be indicated under certain circumstances. Table 2 was constructed by eliminating from consideration those diseases for which definitive therapy is not warranted, not available, or not critical. Empiric treatment of respiratory casualties (patients with undifferentiated febrile illnesses who might have prodromal anthrax, plague, or tularemia would all be managed similarly) might then be entertained. Doxycycline, for example, is effective against most strains of Bacillus anthracis, Yersinia pestis, and Francisella tularensis, as well as against Coxiella burnetii, and the Brucellae. Other tetracyclines and fluoroquinolones might also be considered. Keep in mind that such therapy is, in no way, a substitute for a careful and thorough diagnostic evaluation, when conditions permit such an evaluation.
VII. Practice good infection control. Standard precautions provide adequate protection against most infectious diseases, including those potentially employed in a biological attack. Anthrax, tularemia, brucellosis, glanders, Q- fever, VEE, and the toxin-mediated diseases are not generally contagious, and victims can be safely managed using standard precautions. Such precautions should be familiar to all clinicians. Under certain circumstances, however, one of three forms of transmission-based precautions would be warranted. Smallpox victims should, wherever possible, be managed using ‘airborne precautions’ (including, ideally, a HEPA-filter mask). Pneumonic plague warrants the use of ‘droplet precautions’ (which include, among other measures, the wearing of a simple surgical mask), and certain viral hemorrhagic fevers require ‘contact precautions.’
VIII. Alert the proper authorities. In any military context, the command should immediately be notified of casualties potentially exposed to chemical or biological agents. The clinical laboratory should also be notified. This will enable laboratory personnel to take proper precautions when handling specimens and will also permit the optimal use of various diagnostic modalities. Chemical Corps and preventive medicine personnel should be contacted to assist in the delineation of contaminated areas and the search for further victims.
In a civilian context, such notification would typically be made through local and/or regional health department channels. In the U.S., larger cities often have their own health departments. In most other areas, the county represents the lowest echelon health jurisdiction. In some rural areas, practitioners would access the state health department directly. Once alerted, local and regional health authorities are normally well-versed on the mechanisms for requesting additional support from health officials at higher jurisdictions. Each practitioner should have a point of contact with such agencies and should be familiar with mechanisms for contacting them before a crisis arises. A list of useful points of contact is provided in Table 3.
Local Law Enforcement Authorities *
Local or County Health Department *
State Health Department *
CDC Emergency Response Hotline:
770-488-7100
CDC Bioterrorism Preparedness & Response Program:
404-639-0385
CDC Emergency Preparedness Resources:
http://www.bt.cdc.gov
Strategic National Stockpile:
Access through State Health Dept
FBI (general point of contact):
202-324-3000
FBI (suspicious package info):
http://www.fbi.gov/pressrel/pressrel01/mail3.pdf
USAMRIID General Information:
http://www.usamriid.army.mil
USAMRICD Training Materials:
http://ccc.apgea.army.mil
U.S. Army Medical NBC Defense Information:
http://www.nbc-med.org
Johns Hopkins Center for Civilian Biodefense:
http://www.hopkins-biodefense.org
Infectious Diseases Society of America:
http://www.idsociety.org/bt/toc.htm
Table 3. Points of Contact and Training Resources. *Clinicians and Response Planners are encouraged to post this list in an accessible location. Specific local and state points of contact should be included.
IX. Assist in the epidemiologic investigation and manage the psychological consequences. All health-care providers must have a basic understanding of epidemiological principles. Even under austere conditions, a rudimentary epidemiologic investigation may assist in diagnosis and in the discovery of additional BW victims. Clinicians should, at the very least, query patients about illness onset and symptoms, potential exposures, ill unit members, food/water sources, unusual munitions or spray devices, vector exposures; and develop a line listing of potential cases. Such early discovery might, in turn, permit post-exposure prophylaxis, thereby avoiding excess morbidity and mortality. Public health officials would normally conduct more elaborate epidemiologic investigations and should be contacted as soon as one suspects the possibility of a biological attack. In a military setting, preventive medicine officers, field sanitation personnel, epidemiology technicians, environmental science officers, and veterinary officers are all available to assist the clinician in conducting an epidemiologic investigation.
In addition to implementing specific medical countermeasures and initiating an epidemiologic investigation, the clinician must be prepared to address the psychological effects of a known, suspected, or feared exposure. Such an exposure (or threat of exposure) can provoke fear and anxiety in the population, and may result in overwhelming numbers of patients seeking medical evaluation. Many of these will likely have unexplained symptoms and many may demand antidotes and other therapies. Moreover, symptoms due to anxiety and autonomic arousal, as well as the side effects of postexposure antibiotic prophylaxis may suggest prodromal disease due to biological-agent exposure, and pose challenges in differential diagnosis. This ‘behavioral contagion’ is best prevented by good, proactive, risk communication from health and government authorities. Such communication should include a realistic assessment of the risk of exposure, information about the resulting disease, and what to do and who to contact for suspected exposure. Risk communication must be timely, accurate, consistent, and well coordinated.
