Field Management of Biological Casualities Handbook (TI16D)
 |
|
|
|
BIOLOGICAL AGENTS
The potential use of biological agents on the future battlefield is based on numerous historical precedents. The earliest documented use of a biological agent was in the 6th century B.C. by the Assyrians. The Assyrians poisoned enemy water wells with rye ergot to induce severe gastrointestinal effects. The Black Plague that decimated Europe during the Middle Ages may have begun when the survivors of the siege of Kaffa returned to Europe. During the siege of Kaffa, the besieging Tartar army experienced an outbreak of bubonic plague, and in an effort to induce the surrender of Kaffa, hurled corpses of the bubonic plague victims into the city. This tactic resulted in the surrender of Kaffa and the introduction of the Bubonic Plague, which infected a portion of the defenders.
The use of smallpox as a weapon has been well documented. The British army used smallpox against the Native Americans who were loyal to the French during the French and Indian War with devastating results. The American army, during the subjugation of the Native Americans of Great Plains, used smallpox infected blankets in the same way the British had and with similarly devastating results.
The end of World War II brought the revelation of the intensive research effort by the Imperial Japanese army into the effective means of biological agent production, the medical effects of biological agent exposure, and the best method for delivering these agents to a target.
The most recent indication of offensive biological warfare capability came from Team 7 of the United Nations Special Commission who conducted inspections of Iraqi biological warfare research and development. The Iraqi government announced that prior to Operation Desert Storm, research had been conducted into the use of Bacillus antracis (anthrax), botulinum toxins, and Clostridium perfringens. Thus, had the air war not been so effective, Coalition ground forces may have faced biological warfare agents.
CLASSIFICATION OF BIOLOGICAL AGENTS
The U.S. classifies biological agents into three general categories - pathogens, toxins, or other agents of biological origin.- Pathogens are disease-producing microorganisms such as bacteria, mycoplasma, rickettsia, fungi, or viruses. These microorganisms may be naturally occurring or “engineered” by manipulation of recombinant deoxyribonucleic acid (DNA).
- Toxins are poisons naturally produced through the activities of living organisms. Toxins can be produced by plants, microorganisms, and animals. Due to the feasibility of using some form of biochemical engineering to produce toxins, the U.S. has also classified toxins as a biological agent. Examples of these naturally occurring organic chemical compounds are proteins, polypeptides, and alkaloids.
- Other agents of biological origin are a class of biological agent that can be found in the human body in very small quantities, but if introduced in large quantities, causes severe adverse effects or death. The most notable examples of this class are the bioregulators/modulators (BRM). The BRMs can be small molecules of peptides that act as neurotransmitters and/or modifiers of neural responses.
CHARACTERISTICS OF BIOLOGICAL AGENTS
The qualities that are most advantageous to have in a biological agent and in the target population are high infectivity or toxic properties, desired contagiousness, severity of effects, short incubation period, and susceptibility of target population. The identification of biological attack and identification of a specific agent present serious problems in a tactical situation.- High infectivity or toxic properties. A highly desirable characteristic would be the ability of the agent to produce an effect with the smallest number of organisms or the least amount of agent (e.g., toxins in gram weights) possible.
- Desired contagiousness. Being able to predict the agent’s effect on the target population, the spread of the agent out of the target area, and the length of the agent’s ability to cause the desired effect are all critical criteria of a biological agent. Although the ability of an agent to cause contagious transmission between humans has been seen as an undesirable trait, the use of these types of agents in “ethnic cleansing” style operations cannot be dismissed.
- Severity of effects. The use of a biological agent may be contemplated to cause only incapacitating effects in the target populations, or devastating lethal effects may be desired. The predictability of the end result of a biological agent release is critical.
- Susceptibility of target population. The introduction of any biological organism into a population that has little or no resistance or has not been immunized will wreak havoc, even if the selected agent causes only incapacitating effects.
TACTICAL AND MEDICAL IMPLICATIONS OF BIOLOGICAL WARFARE
The tactical and medical impact of biological weapons employment can be minimized if medical personnel are familiar with the operational aspects of biological agent exposure. The operational aspects are listed below.- Potential methods of dissemination
- Routes of entry
- Protection
- Detection
- Decontamination
The medical aspects of biological agent exposure are as follows:- Potential biological agents
- Symptoms of exposure
- Transmission of infectious agent
- Incubation period of infectious agen
- Treatment of disease
- Vaccination
OPERATIONAL ASPECTS OF BIOLOGICAL WARFARE
Potential methods of dissemination. The ability to produce biological agents and the means of employment are feasible with minimal resources. The traditional methods of dissemination are by aerosol, large liquid drops, dry powders, and arthropod vectors. Employment of one or more of these methods is not beyond the capability of most moderately industrialized nations. Also, dissemination by covert means, whether in a tactical environment or by terrorists, must also be considered.- Aerosol dissemination. A live microorganism cultured in a moist environment can be introduced into the air in a wet aerosol. The use of an aerosol is considered more likely than any of the remaining methods.
- Large liquid drops (cutaneous). Using large liquid drops of agent, usually toxins will cause ground contamination similar to that of a persistent chemical agent.
- Dry powder. By employing a process similar to freeze drying, microbiological materials can be stored as a dry powder. This dry powder state causes a drastic increase in the stability of the agent in the open environment and makes dissemination much easier. In addition to dry powder, a pathogen can be protected by micro-encapsulation, and its use would be similar to a dry powder.
- Arthropod vector. This method of dissemination is the least likely to be used because of the cost of producing the vectors, controlling the vectors after their release, and natural predators that might destroy them. However, a vector might be able to circumvent protective clothing and mask.
- Covert. The use of a biological agent by a terrorist group is a potential threat. Any of these dissemination methods might be used against large population centers or military or political targets.
Routes of entry. Generally speaking, certain methods of dissemination are designed to achieve a desired effect through one primary route of entry. Effects that are achieved as a result of a secondary route of entry are considered a bonus. The physical form in which the biological agent is disseminated can be generally associated with a particular route of entry.- Respiratory. Live microorganisms that remain suspended in the air in a wet aerosol pose an extremely effective method of introducing a disease into the target organism through the respiratory tract. Biological agents in a dry powder and microencapsulated can also be used to infect the target organism or population through a respiratory means.
- Cutaneous. The use of large liquid drops could deny terrain and cause secondary effects in humans who enter the area unaware of the threat through cutaneous means or by ingestion. Biological agents in a dry powder state and micro-encapsulated can also be used to infect the target population through a cutaneous means.
- Ingestion. The introduction of a biological agent into a drinking water supply or food production facilities could have a significant impact on a target population. The use of a dry powder or micro-encapsulated pathogen against a target population, although employed primarily for respiratory effects, has the additional bonus effect of infecting the target organism by being swallowed or introduced through touch.
Protection.
The topic of protection is fairly simple when limited to the physical protection afforded by the Battle Dress Overgarment (BDO), chemical protective boots and gloves, and M40 series of protective masks. When fully encapsulated at MOPP IV, the soldier has complete respiratory and physical protection against all known biological agents.
The first action that all soldiers can take to better protect themselves from a biological agent is to understand and maintain good personal health while in garrison and in the field. At a minimum, this should include maintaining good physical fitness and proper weight, keeping immunizations up to date, practicing good personal hygiene, following field sanitation guidelines, and training on individual and collective nuclear/biological/chemical (NBC) defense tasks.
Prior to deployment, medical, chemical, and command staffs must completely understand the threat's ability in order to conduct biological warfare operations.
Detection.
The U.S. Army has not fielded equipment capable of detecting and identifying biological agents; we have no remote biological agent detection capability. This lack of equipment increases the soldier's need to be aware of certain indicators (listed below) that suggest an attack is occurring or has already taken place.- Mist or fog sprayed by slow moving aircraft or helicopter.
- Aerial bombs that pop, rather than explode.
- Artillery shells that detonate with less powerful explosions than HE rounds.
- Mysterious illness in both the soldier and civilian population that approaches epidemic numbers.
- Large numbers of dead wild and domestic animals.
- Unusual concentrations of insects or sighting of insects not normally found in the geographical region.
Some of these indicators are the same as those that could be found after a chemical attack, but with one critical difference. After taking immediate action to protect themselves, soldiers will be unable to detect and identify chemical agents vapors or liquids. In the absence of reactions, a NBC-4 (Biological) report must be sent to higher headquarters.
Decontamination.
Biological agents pose a contact hazard to soldiers by direct deposit on the skin and by indirect transfer from a contaminated surface to the soldier's skin, mouth, nose, or respiratory tract. When the soldier suspects that he has come in contact with contamination from a biological attack, he must decontaminate immediately.
Decontamination of exposed skin can be accomplished with the M291 SDK. When biological contamination is suspected, a 0.5% chlorine solution or warm soapy water can be used to remove the suspected agent from the skin.
Performing operator spray-down with the M11 or M13 portable decon apparatus and hasty decontamination with power-driven decontamination apparatus will flush biological agents from the surface of equipment and lower the direct and indirect transfer hazard.
The critical point to understand about biological agent contamination is not that the decontamination process destroys the agent, but that it is physically removed from the skin or equipment. Removal of the agent significantly decreases the hazard to the soldier.
MEDICAL ASPECTS OF BIOLOGICAL AGENT EXPOSURE
Potential biological agents. The biological agents discussed in this section are listed below. These agents can be disseminated as an aerosol to specifically induce an effective dose via the respiratory tract.- Smallpox
- Tularemia
- Cholera
- Bubonic Plague
- Anthrax
- Botulism
- Staphylococcal Enterotoxin B (SEB)
- Toxins
The following topics will be covered for each potential biological agent:- Symptoms of exposure
- Transmission of infectious agent
- Incubation period of infectious agent
- Treatment of disease
- Vaccination
NOTE: Page numbers in the following text refer to FM 8-33, Control of Communicable Diseases in Man, 16th Edition, The American Public Health Association, Washington, D.C., 1995.
Smallpox
This systemic viral disease was declared globally eradicated in 1979 by the World Health Organization. The only known samples of the disease-causing Variola Virus are in the "hot" labs at the Centers for Disease Control (CDC) in Atlanta, GA, and in the CDC's Russian counterpart in Moscow. Vaccines are stockpiled. (page 425)
Symptoms of exposure are sudden onset of fever, headache, severe backache, malaise, rigors, and occasionally, abdominal pain. After two to three days, temperature falls and a rash appears. The rash develops into macules, papules, vesicles, pustules, and finally, scabs. The casualty is infectious during the entire term of the disease, which is usually three to four weeks. The first week is the worst.
Transmission of infectious agent. Transmission of the disease is by respiratory discharge, bed linens, the patient's clothing, or skin contact with the scabs. Complete sterile handling should be enforced with complete quarantine for up to four weeks after the rash appears.
Incubation period of infectious agent averages from 7 to 12 days, with 10 to 12 days before onset of illness, and 2 to 4 days more to onset of rash.
Treatment of disease: none, other than supportive care.
Tularemia
Tularemia is a zoonotic, bacterial disease with a variety of clinical manifestations related to route of introduction and the virulence of the disease agent. Stockpiles of vaccines for large usage do not exist. The only vaccine presently available is at the U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD. (page 501)
Symptoms of exposure. Usually presents as an indolent ulcer at the site of introduction of the organism with swelling of the regional lymph nodes. There may be only one or more enlarged and painful lymph nodes that may rupture and leak. Ingestion of organisms may produce a painful pharyngitis, abdominal pain, diarrhea, and vomiting. Inhalation of organisms may cause a pneumonia-like illness or systemic, febrile, septicemic syndrome. All forms may be complicated by pneumonia.
Transmission of infectious agent. The bacteria which causes Tularemia naturally infects numerous wild animals, especially rabbits, hares, muskrats, beavers, and some hard ticks. It is transmitted to man through the bite of arthropod vectors, though ingesting or handling contaminated water and flesh, or by inhaling contaminated dust.
Incubation period of infectious agent ranges from 1 to 14 days, usually 3 to 5 days.
Treatment of disease. Streptomycin or gentamycin given for 7 to 14 days are the drugs of choice; the tetracyclines and chloramphenicol are bacteriostatic and effective when continued for no less than 14 days. Aspiration, incision and drainage, or biopsy of an inflamed lymph node can spread the infection and must be covered with prompt and specific antibiotics.
Cholera
Cholera is an acute, bacterial enteric disease. Vaccines of moderate, short-term effect (three to six months) are stockpiled. (page 97)
Symptoms of exposure are sudden onset of profuse, painless, watery stools, occasional vomiting, rapid dehydration, acidosis, and circulatory collapse.
Transmission of infectious agent. The primary sources are water-borne contamination, fecal matter, or the ingestion of contaminated foods.
Incubation period of infectious agent is a few hours to five days; usually two to three days.
Treatment of disease. Prompt fluid therapy with volumes of electrolyte solution adequate to correct dehydration, acidosis, and hypokalemia is the keystone of cholera treatment. Mild to moderate dehydration should be treated with oral rehydration solutions; severe dehydration should be treated with IV. Tetracycline or TMP-SMX shortens the duration of diarrhea and reduces the volume of fluid lost.
Plague
Plague is a specific zoonosis involving rodents and their fleas, which transfer the bacterial infection to people. Vaccination is protective against the bubonic form of the disease, but not against the primary respiratory form. (page 355)
Symptoms of exposure. Initial signs and symptoms may be nonspecific with fever, chills, malaise, myalgia, nausea, prostration, sore throat, and headache. Commonly a lymphadenitis develops in those lymph nodes receiving draining from the site of the fleabite (Bubonic Plague). Bubonic Plague can progress through the bloodstream to diverse parts of the body to cause meningitis, shock, bleeding, and pneumonia (secondary pneumonic plague).
Transmission of infectious agent. The most frequent source of human exposure is the bite of infected fleas. Other important sources include handling of tissues of infected animals. Persons with secondary pneumonic plague can spread the disease from person to person through respiratory droplets to cause primary pneumonic or pharyngeal plague.
Incubation period of infectious agent is from one to seven days but may be longer in immunized individuals; two to four days for primary pneumonia.
Treatment of disease. Streptomycin is the drug of choice; gentamycin is an alternate. Tetracyclines and chloramphenicol are other alternatives. All are effective if used early in the course of disease.
Anthrax
Anthrax is an acute bacterial zoonotic disease that usually affects the skin but may also involve the mediastinum or intestinal tract. Vaccines are stockpiled. (page 20)
Symptoms of exposure. Skin exposure: itching of exposed skin surface, followed by a lesion that at first becomes papular, then vesculated, and develops into a depressed black eschar in two to six days. This eschar is usually surrounded by mild to moderate edema and sometimes small secondary vesicles. The inhaled anthrax presents symptoms resembling a common upper respiratory tract infection (URI) at first, with acute symptoms of respiratory distress following. X-ray evidence of mediastinal widening, fever, and shock follow in three to five days, with death ensuing shortly thereafter. Ingested anthrax presents with abdominal distress followed by fever, signs of septicemia, and then death in a typical case.
Transmission of infectious agent. Cutaneous exposure occurs when handling dying infected animal tissue, contaminated hair, wool, hides, or products made from infected, slaughtered animals. Inhalation anthrax results from inhaling anthrax spores. Intestinal exposure is caused by ingestion of infected meat.
Incubation period of infectious agent is from a few hours to 7 days, with most cases occurring within 48 hours after exposure.
Treatment of disease. Penicillin is the drug of choice and is given for five to seven days. Tetracyclines, erythromycin, and chloramphenicol are also effective.
Rickettsia - Query Fever (Q Fever)
Q Fever is an acute rickettsia disease characterized by fever. Vaccines are not stockpiled for general use, but can be obtained from the U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD. (page 281)
Symptoms of exposure are sudden onset of headache behind the eyeballs, general weakness, and severe sweats, chills, and malaise.
Transmission of infectious agent: carried by domestic animals (cattle, sheep, goats) and ticks. Spread by airborne dissemination of infected excreta and also by direct contact with infected animal products (wool, straw, milk) and excreta.
The incubation period of infectious agent depends on the size of the infecting dose; however the usual incubation period is 2 to 14 days. Q Fever generally occurs as a self-limiting, febrile illness lasting two days to two weeks.
Treatment of disease: tetracyclines administered orally and continued for several days after the patient is afebrile; reinstitute if relapse occurs.
Toxins
Toxins are chemical compounds of biological origin that may be lethal or incapacitating on skin contact or when inhaled or ingested. They are high molecular weight proteins capable of reacting with the human immune system antibodies. The recognition of a toxin attack and identification of a specific toxin present serious problems in a tactical deployment.
Sources of toxins. Toxins are naturally produced by bacteria, marine plankton (dinoflagellate), marine animals, plants, and fungi.
Mechanism of action. Generally speaking, toxins affect the body through mechanisms which cause reactions similar to nerve, blister, vomiting, and choking agents.
Cytotoxin. Toxins that destroy or interfere with metabolic processes fall into this general description. A cytotoxin can affect the digestive tract, respiratory system, circulatory system, or the skin. Some effects may appear associated with blister, choking, or vomiting agents.
Neurotoxin. The neurotoxins that are postsynaptic acetylcholinesterase inhibitors will induce nerve agent like symptoms. These postsynaptic neurotoxins cause ion channel permeability. Convulsions and pinpointing of pupils are the most noticeable symptoms. Some neurotoxins that are presynaptic inhibitors block the release of acetylcholine. Usually the symptoms associated with these presynaptic inhibitors are flaccid or limp paralysis, blurred vision, light sensitivity due to dilation of pupils, tremors, and confused behavior.
Medical care. In a field environment, only supportive care is available. The critical fact to remember is that antitoxins for many toxins are available, but specific identification of the toxin must occur, and this will not happen in a field setting. If toxin exposure is suspected, evacuation must occur as rapidly as possible.
Botulism
Botulism is a severe intoxication resulting from ingestion of botulism toxin. Ingestion usually occurs as a result of eating contaminated food.
Symptoms of exposure. The symptoms are related primarily to effects on the nervous system. Blurred or double vision, difficulty swallowing, and dry mouth are the most common initial complaints. After the initial symptoms, an alert casualty can experience progressive, flaccid paralysis that moves downward through his body affecting the entire body evenly. The casualty may also experience vomiting, constipation, or diarrhea.
Transmission of infectious agent. The classic method of transmission of the botulism toxin is by ingesting contaminated food. The toxin grows in airtight packaging containing food products that have been improperly processed. Boiling destroys the toxin. No known person-to-person transmission of this toxic has ever been documented.
Incubation period of infectious agent. Neurological symptoms can appear within 12 to 36 hours and up to several days after ingestion of the toxin. The shorter the onset of symptoms, the more severe the disease and the higher the fatality rate.
Treatment of disease: intravenous and intramuscular administration as soon as possible of trivalent botulinum anti-toxin (types A, B, and E). The most critical aspect of effective treatment is placing the casualty in an intensive care unit so that respiratory failure, the usual cause of death, can be properly managed should it occur. The anti-toxin is available from the Centers for Disease Control (CDC).
Staphylococcal Enterotoxin B (SEB)
The toxin SEB is one of several exotoxins (toxins found outside the bacterial cell) that are produced by Staphylococcus aureus. When ingested, SEB can produce symptoms of food poisoning. When inhaled, SEB causes a reaction described below which causes significant morbidity and potential mortality. (page 402)
Symptoms of exposure. Symptoms of respiratory exposure to SEB begin within 3 to 12 hours. The casualty can experience sudden onset of fever, chills, headaches, muscle pain, and nonproductive cough. When a severe exposure occurs, the casualty will have difficulty breathing and experience pain behind the sternum. Fever may reach 103°F to 106°F and last two to five days. Cough can last one to four weeks.
Transmission of infectious agent. Soldiers may be exposed to SEB after an aerosol attack because of the relative stability of the SEB toxin in air.
Incubation period of infectious agent. Symptoms occur within 3 to 12 hours after inhalation.
Treatment of disease. Treatment is limited to supportive care, including treatment of shock and lower hypoxia.
Trichothecene mycotoxins. These toxins act immediately on the eyes and skin by causing irritation, followed rapidly by death or a prolonged period of continued illness with death occurring weeks later. Death is usually caused by bone marrow suppression, liver failure, or internal bleeding. Within 10 to 30 minutes after exposure, the individual experiences vomiting, dizziness, rapid heart beat, and chest pain. Within hours, the individual can experience bloody vomiting, bloody diarrhea, and if the exposure was on the skin, blistering.
Other Toxins
Saxitoxin. Produced naturally by the dinoflagellate plankton, this toxin kills within ten seconds.
Tetrodotoxin. Produced by the newt, puffer fish, and blue-ringed octopus, this toxin is a rapid, lethal, neuromuscular blocker that acts within five minutes to one hour.
Palytoxin. Produced by the coelenterate (soft coral animal), this toxin is a very rapid-acting, lethal neurotoxin that acts within five minutes. Symptoms are rapid muscle paralysis and collapse.
Ricin. Produced from the castor bean seed, the activity of this toxin is delayed by 1 to 12 hours, but is a lethal cytotoxin that causes weakness, fever, cough, vomiting, and severe cramps. Ricin has been characterized as being 100 times more deadly than cobra venom.
Mycotoxins (fungus toxins). Typical of this group of toxins is the trichlothecene group that contains T2, nivalenol, and deoxynivalenol. Severe poisoning of these toxins causes ataxia, shock, collapse, vomiting, diarrhea, and death. |
|
| |
|
|
| |
|
|
|
|
|
|
| |
|
