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Nevada: Terrorism Response for Healthcare Professionals

Lauren Robertson, BA, MPT

Sharon A. Sanders, RN

Susan Walters Schmid, BA, MA, PhD (candidate)

This course meets requirements for healthcare workers in the state of Nevada who may be called upon to treat people exposed to chemical, biologic, radioactive, or nuclear agents used in a terrorist act.

Wild Iris Medical Education is an approved provider (#PA-54) of continuing nursing education by the Washington State Nurses Association, an accredited approver by the American Nurses Credentialing Center's Commission on Accreditation. Our courses fulfill continuing nursing education requirements in all 50 states.
Wild Iris Medical Education is an approved provider (#0007) of continuing education by the Continuing Education Coordinating Board for Emergency Medical Services (CECBEMS).

This course meets the requirement of Assembly Bill 250 (2003), which requires that several types of healthcare professionals, including nurses, take four hours of continuing education "relating to the medical consequences of an act of terrorism that involves the use of a weapon of mass destruction."

Much of the information in this course is taken from the Department of Health and Human Services, Centers for Disease Control and Prevention. Learning objectives and post test were prepared by Susan Walters Schmid, BA, MA.

TERRORISM AND WEAPONS OF MASS DESTRUCTION

Terrorism

Terrorism has been part of our public consciousness since the events of September 11, 2001. Acts of terrorism and the means by which they might be carried out are of special concern to healthcare professionals, who are called upon to treat people following a terrorist attack.

The Federal Emergency Management Agency (FEMA) describes terrorism as "the use of force or violence against persons or property in violation of the criminal laws of the United States for purposes of intimidation, coercion, or ransom. Terrorists often use threats to create fear among the public, to try to convince citizens that their government is powerless to prevent terrorism, and to get immediate publicity for their cause" (FEMA, 2007).

In the Code of Federal Regulations, terrorism is defined as "the unlawful use of force and violence against persons or property to intimidate or coerce a government, the civilian population, or any segment thereof, in furtherance of political or social objectives." Terrorism is often categorized as "domestic" or "international." This distinction refers not to where the terrorist act takes place but to the origin of the individuals or groups responsible for it. For healthcare professionals facing the medical consequences of such an act, this is unlikely to be relevant.

Unlike strictly criminal acts, terrorism generally reflects "motivations that are chiefly political, ideological, or religious; often, some element of symbolism in the choice of target, together with the desire to elicit fear in a larger audience beyond the immediate victims of an attack" (FEMA, 2007).

Healthcare workers need to be aware that the effects of fear will loom large after an incident of terrorism and these effects need to be anticipated and addressed even in patients who have sustained little or no physical injury. In addition, psychological effects are recognized consequences of certain types of injuries that will be discussed in this course.

Weapons of Mass Destruction

Weapons of mass destruction (WMD) is a term that has become increasingly familiar since 9/11. Not everyone means precisely the same thing when they use the term, but the definition used by the U.S. military may be the most useful and generally understood:

Weapons that are capable of a high order of destruction and/or of being used in such a manner as to destroy large numbers of people. Weapons of mass destruction can be high explosives or nuclear, biological, chemical, or radiological weapons, but exclude the means of transporting or propelling the weapon where such means is a separable and divisible part of the weapon. (DOD, 2007)

The possibility that terrorists might resort to the use of WMD is of grave concern to many, including healthcare professionals. The various types of WMD—chemical, biologic, radiologic, nuclear—vary in their ability to cause damage, in their ease of production and use, in the kinds of physical and human damage they can be expected to cause, and in their likelihood of use by terrorist organizations.

Chemical warfare (CW) agents are nonliving, manufactured chemicals that are highly toxic and can enter the body through the lungs or the skin. They cause illness or death within minutes to hours after exposure (CNS, 2007a).

Biological warfare (BW) agents are microorganisms such as viruses and bacteria that infect humans, livestock, or crops and cause an incapacitating or fatal disease. Symptoms of illness do not appear immediately but only after a delay, or "incubation period," that may last for days to weeks (CNS, 2007a).

Toxins—nonliving poisons produced by living plants, insects, and animals—are in a gray area between CW and BW agents. They generally have an incubation period of hours to days, longer than that of CW agents but shorter than that of BW agents (CNS, 2007a).

For purposes of this course, toxins are included with biologic agents.

Radiologic and nuclear warfare agents rely on the same sources for damage—explosive power and radiation—but there is a distinction in their forms. In addition, true nuclear weapons produce tremendous heat, which can cause burns and start fires. In the last fifty years, most radiation injuries have been the result of accidents; however, the intentional deployment of a nuclear or radiologic device is a potential terrorist threat.

Modern nuclear threats can be divided into five general categories: (1) an attack on nuclear power plants, (2) a malevolent act using simple radiologic devices, (3) terrorist use of a radiologic dispersal device, (4) detonation of an improvised nuclear device, and (5) detonation of a sophisticated nuclear weapon. Whereas incidents involving simple devices and radiologic dispersal devices would probably cause a limited number of casualties, those involving improvised nuclear devices and small nuclear weapons would result in mass casualties. (Waselenko et al., 2004)

All WMD present advantages and obstacles to those who would create and use them. Some require a certain level of skill, others require access to controlled or illegal substances, and still others require significant financial outlays and/or the cooperation of persons in positions of security or power. Some weapons could produce significant damage and high death tolls, while the greatest effects of others would be widespread panic and expensive cleanup operations.

RADIOLOGIC AND NUCLEAR WEAPONS

Both radiologic and nuclear devices can damage and contaminate. The use of "dirty bombs" (radiologic dispersion devices, or RDDs) is seen as the more likely occurrence of the two. These devices require little more skill than is needed to make a conventional bomb. (They utilize conventional explosives to disperse a radioactive material packaged in the device, as opposed to a nuclear device, which creates radiation with its explosion.)

While death and injuries would result from the explosion of an RDD, it is unlikely that many would die from radiation poisoning. However, the costs of cleanup could be considerable. These devices are attractive to some groups because they are relatively easy to create and because they will not generally do a great deal of damage but will play on the heightened fear of radiation among the general public to cause widespread panic and disruption, which is often a group's real goal (CISAC, 2002a; CNS, 2007b).

Nuclear weapons present significantly higher obstacles in terms of the skill needed to produce them and the financial and logistical support needed to acquire materials, prepare the device, and transport it. However, the potential for damage, injuries, and death is much higher as well, as these are significantly more powerful weapons.

CHEMICAL AND BIOLOGIC WEAPONS

Chemical and biologic weapons are financially and logistically easier to acquire than radiologic or nuclear weapons. They will cause more casualties and have a greater psychological impact than conventional weapons, but cause less destruction than devices involving radiation. Chemical weapons are somewhat easier than other weapons for terrorist groups, or even individuals, to manufacture because the manufacturing knowledge is readily available, many precursor chemicals have legitimate uses and are thus legally available, there is poor security around these chemicals in some countries, and small chemical manufacturing equipment is commonly available.

The nature of chemical weapons terrorism is such that a group needs to be motivated to cause random mass casualties, organized in a way that they are unlikely to be penetrated by law enforcement agencies, and possessing or having access to the technological expertise to acquire and deploy the weapons. In the past, few groups possessed these attributes, but changes in the nature of terrorism over the last fifty years may have contributed to a rise in groups with these capabilities (CNS, 2008).

While acts of terrorism are frightening and tend to receive intense media attention, there have been few truly successful incidents in recent years, other than war zone–related events. The U.S. government was already actively working to combat terrorist threats before September 11, 2001, and has since stepped up its efforts. For the general public and healthcare workers, education about the dangers and proper responses to terrorist activities, along with thorough emergency preparedness, are the best available defense.

RADIATION

Types of Radiation

Radiation is any form of energy propagated as rays, waves, or energetic particles that travel (radiate) from their source. Radiation can travel through the air or through a material medium (CISAC, 2002b,c).

Radioactive materials are composed of atoms that are unstable. An unstable atom gives off its excess energy until it becomes stable. The energy emitted is radiation. The process by which an atom changes from an unstable state to a more stable state by emitting radiation is called radioactive decay or radioactivity (CISAC, 2002b,c).

Radiation is often divided into ionizing and non-ionizing radiation. Radiation that has enough energy to move atoms in a molecule or cause them to vibrate, but not enough to change them chemically, is referred to as non-ionizing radiation. Examples of this kind of radiation are radio waves and visible light (CISAC, 2002b).

Radiation that falls within the ionizing radiation range (alpha, beta, and gamma rays) has enough energy to break the bonds that tie electrons into the atoms or molecules that make up ordinary substances. This is the type that people usually think of as "radiation" when dealing with nuclear dangers. Ironically, this is also the type of radiation that is used for medical treatment and in many manufacturing processes (CISAC, 2002c).

Compared with other types of radiation that may be absorbed, ionizing radiation deposits a large amount of energy into a small area. All ionizing radiation is capable, directly or indirectly, of removing electrons from most molecules. This property of ionizing radiation lies at the root of both its usefulness and its dangers (CISAC, 2002c).

Radiation cannot be detected by the human senses. A radiologic survey conducted with specialized equipment is the only way to confirm the presence of radiation. If a terrorist event involves the use of radioactive material, both patient exposure and contamination must be assessed.

Exposure occurs when a person is near a radiation source. People exposed to a source of radiation can suffer radiation illness if the dose is high enough, but they do not become radioactive. For example, an x-ray machine is a source of radiation exposure, yet a person does not become radioactive or pose a risk to others following a chest x-ray (CDC, 2005ra).

Measuring Radiation

When scientists measure radiation, they use different terms depending on whether they are discussing radiation coming from a radioactive source, the radiation dose absorbed by a person, or the risk that a person will suffer health effects (biologic risk) from exposure.

Most scientists in the international community measure radiation using the Système International d'Unités (SI), a uniform system of weights and measures that evolved from the metric system. In the United States, however, the conventional system of measurement is still widely used.

Different units of measure are chosen depending on what aspect of radiation is being measured. For example, the amount of radiation being given off, or emitted, by a radioactive material is measured using the conventional unit curie (Ci), named for the famed scientist Marie Curie, or the SI unit becquerel (Bq).

The radiation dose absorbed by a person (that is, the amount of energy deposited in human tissue by radiation) is measured using the conventional unit rad or the SI unit gray (Gy). The biologic risk of exposure to radiation (that is, the risk that a person will suffer health effects from an exposure to radiation) is measured using the conventional unit rem or the SI unit sievert (Sv) (CDC, 2003a).

TYPES OF RADIATION INJURY

The only non-test deployment of nuclear weapons was the 1945 dropping of the atomic bombs on Hiroshima and Nagasaki, Japan, near the end of World War II. Those at the bomb's center were killed immediately by thermal and shock forces as well as intense radiation poisoning. Others at varying distances from the bomb's center were injured and died later. Still others are alive today, but many of them have suffered from the latent effects of radiation exposure. Patterns of aftereffects are known, as are the patterns of radiation illness and injury that follow closely upon exposure. Understanding these patterns will aid in diagnosis and treatment of radiation-induced injury or illness.

Regardless of where or how radiation exposure happens, three types of radiation-induced injury can occur: external irradiation, contamination with radioactive materials, and incorporation of radioactive material into body cells, tissues, or organs (ORISE, 2000/2002d).

External Irradiation

External irradiation occurs when all or part of the body is exposed to penetrating radiation from an external source. During exposure this radiation can be absorbed by the body or it can pass completely through the body. A similar thing occurs during an ordinary chest x-ray. Following external exposure, an individual is not radioactive and can be treated like any other patient (ORISE, 2000/2002d).

Contamination

The second type of radiation injury involves contamination with radioactive materials. Contamination means that radioactive materials—in the form of gases, liquids, or solids—are released into the environment and contaminate people externally, internally, or both. The external surface of the body, such as the skin, can become contaminated, and if radioactive materials get inside the body through the lungs, gut, or wounds, the contaminant can become deposited internally (ORISE, 2000/2002d).

Incorporation

The third type of radiation injury that can occur is incorporation of radioactive material. Incorporation refers to the uptake of radioactive materials by body cells, tissues, and target organs such as bone, liver, thyroid, or kidney. In general, radioactive materials are distributed throughout the body based upon their chemical properties. Incorporation cannot occur unless contamination has occurred (ORISE, 2000/2002d).

RADIATION-INDUCED ILLNESS

Acute Radiation Syndrome (ARS)

Acute radiation syndrome (ARS) (sometimes known as radiation toxicity or radiation sickness) is an acute illness caused by irradiation of the entire body, or most of the body, by a high dose of penetrating radiation in a very short period of time (usually a matter of minutes) (CDC, 2005rb). The most probable terrorist events, such as a dirty bomb attack, will likely generate low levels of radiation exposure. If ARS cases are seen, it is likely that casualty numbers will be small (CDC, 2005ra).

Basic symptomatic issues of ARS include:

• Time of exposure, distance from radioactive source, and duration of exposure.
• Patients may present individually if exposed to radioactive sources that are hidden in the community.
• Symptoms can be immediate or delayed, mild or severe, based on radiation dose.
• Nausea and vomiting may occur minutes to days after exposure.
• Early onset of vomiting followed by symptoms of bone marrow suppression, gastrointestinal destruction, and/or cardiovascular/central nervous system effects are indicative of acute illness.
• Depending on the stage of illness, a patient may be asymptomatic. (CDC, 2005ra)

The required conditions for ARS are:

• The radiation dose must be large (> 0.7 Gy, or >70 rads).
• The dose usually must be external (the source of radiation is outside of the patient's body).
• The radiation must be penetrating (able to reach the internal organs).
• The entire body (or a significant portion of it) must have received the dose.
• The dose must have been delivered in a short time (usually a matter of minutes). (CDC, 2005rb)

The three classic ARS syndromes are:

• Bone marrow syndrome (hematopoietic syndrome)
• Gastrointestinal syndrome
• Cardiovascular/CNS syndrome (CDC, 2005rb)

The four stages of ARS are:

• Prodromal stage (N-V-D stage): Classic symptoms are nausea, vomiting, and anorexia—and possibly diarrhea, depending on dose—which occur from minutes to days following exposure. The symptoms may last episodically from minutes to several days.
• Latent stage: The patient looks and feels generally healthy, for a few hours to a few weeks.
• Manifest illness stage: The symptoms depend on the specific syndrome and last from hours to several months.
• Recovery or death: Most patients who do not recover will die within several months of exposure. The recovery process lasts from several weeks to two years. (CDC, 2005rb)

Cutaneous Radiation Syndrome (CRS)

The concept of cutaneous radiation syndrome (CRS) was introduced in recent years to describe the complex pathologic syndrome that results from acute radiation exposure to the skin. Acute radiation syndrome is usually accompanied by some skin damage, but it is also possible to receive a damaging dose to the skin without symptoms of ARS, especially with acute exposures to beta radiation or x-rays. Sometimes this occurs when radioactive materials contaminate a patient's skin or clothes (CDC, 2005rb).

Basic symptomatic issues of CRS include:

• Skin damage that can manifest within hours, days, or weeks after radiation exposure.
• Transient itching, tingling, erythema, or edema within hours or days after exposure, usually followed by a latent period.
• Lesions may not be seen for weeks to months postexposure, but then can be debilitating or even life-threatening.
• Delayed occurrence of lesions is a differentiating factor from thermal burns.
• It is important to note time of occurrence of signs and symptoms and progressive changes in appearance.
• Treat localized injuries symptomatically, focusing on pain and infection control. (CDC, 2005ra)

PROTECTING STAFF AND PATIENTS

The Centers for Disease Control and Prevention (CDC) has established general guidelines for managing patients and protecting staff in the event of radiation exposure. These guidelines are specifically designed for small-scale incidents not resulting from a large or nuclear device.

Mass Casualties
Hospitals and other agencies are also expected to have mass casualty strategies in place, and all appropriate staff should be trained in proper procedures and use of equipment. Many resources are available for establishing triage areas and managing mass casualties. See Resources at the end of this course for further information.

According to the CDC, addressing contamination issues should not delay treatment of life-threatening injuries. It is highly unlikely that the levels of radioactivity associated with a contaminated patient would pose a significant health risk to care providers. In certain rare instances, the presence of imbedded radioactive fragments or large amounts of external contamination may require expedited decontamination, thus it is recommended to include in-house radiation professionals on the response team (CDC, 2005ra). The CDC staff protection guidelines include the following.

Establish an ad hoc triage area:

• Base it on your hospital's disaster plan and the anticipated number of casualties.
• Establish a contaminated area and a clean area separated by a buffer zone.
• Remove your contaminated outer garments when leaving the contaminated area.
• Have your body surveyed with a radiation meter when exiting a contaminated area.

Use standard precautions to protect staff:

• Follow standard guidelines for protection from microbiologic contamination.
• Surgical masks should be adequate.
• N95 masks, if available, are recommended.
• Survey hands and clothing at frequent intervals with a radiation meter.
• Due to fetal sensitivity to radiation, assign pregnant staff to other duties (CDC, 2005ra).

Protective Clothing for Staff

The purpose of protective clothing is to keep bare skin and personal clothing free of contaminants. Members of the radiologic emergency-response teams dress in surgical clothing (scrub suit, gown, mask, cap, eye protection, and gloves). Waterproof shoe covers are used. All open seams and cuffs are taped using masking or adhesive tape. (Fold-over tabs at the end of each taped area aid in removal.) Two pairs of surgical gloves are worn. The first pair of gloves is worn under the arm cuff and secured by tape; the second pair of gloves should be easily removable so the gloves can be replaced if they become contaminated.

Each team member wears a radiation dosimeter attached to the outside of the surgical gown at the neck, where it can be easily removed and read. If available, a film badge or other type of dosimeter can be worn under the surgical gown. A waterproof apron can also be worn by any member of the team who is using liquids for decontamination purposes.

This protective clothing is effective in stopping some, but not all, types of exposure. Lead aprons, such as those used in the x-ray department, are not recommended because they give a false sense of security (ORISE, 2000/2002a).

Decontamination Guidelines for Patients

The CDC offers the following guidelines for managing patients who are believed to have been contaminated either externally or internally with radiation. Before beginning treatment, staff should be sure to take care in following their agency's guidelines for donning protective clothing or equipment.

Survey the patient with a radiation meter:

• Perform surveys using consistent technique and trained personnel.
• Note exceptionally large amounts of surface or embedded radioactive material.
• Handle radioactive objects with forceps and store in lead containers.
• Record location and level of any contamination found. (CDC, 2005ra)

Remove patient clothing:

• Carefully cut clothing and roll it away from the face to contain the contamination.
• Double-bag clothing using radioactive hazardous waste guidelines, label, and save as evidence.
• Repeat patient survey and record level. (CDC, 2005ra)

Cleanse contaminated areas:

• Wash wounds first with saline or water.
• If facial contamination is present, flush eyes, nose, and ears, and rinse mouth.
• Gently cleanse intact skin with soap and water, starting outside the contaminated area and washing inward.
• Do not irritate or abrade the skin.
• Resurvey and note levels.
• Repeat washing until survey indicates radiation level is no more than twice background or the level remains unchanged.
• Cover wounds with waterproof dressing.
• Dispose of wastewater through normal channels.
• For mass casualties, consider establishing separate shower areas for ambulatory and nonambulatory patients. (CDC, 2005ra)

Management of deceased:

• If exposed to a lethal dose of radiation without contamination, a patient is not radioactive and no special precautions are needed.
• Special precautions may be necessary for contaminated deceased. (CDC 2005ra)

INITIAL EVALUATION AND TREATMENT

Treat vomiting immediately. Repeat CBC analysis with special attention to the lymphocyte count every 2 to 3 hours for the first 8 to 12 hours after exposure (and every 4 to 6 hours for the following 2 to 3 days). Precisely record all clinical symptoms, particularly nausea, vomiting, diarrhea, and itching, reddening, or blistering of the skin. Be sure to include time of onset.

Note and record areas of erythema. If possible, take color photographs of suspected radiation skin damage. Consider tissue and blood typing, as well as initiating viral prophylaxis. Promptly consult with radiation, hematology, and radiotherapy experts about dosimetry, prognosis, and treatment options. Call the Radiation Emergency Assistance Center to record the incident in the Radiation Accident Registry System (see numbers under Resources at the end of this course).

After consultation, begin the following treatment (as indicated):

• Supportive care in a clean environment (eg, burn unit)
• Prevention and treatment of infections
• Stimulation of hematopoiesis by use of growth factors
• Stem cell transfusions or platelet transfusions (if platelet count too low)
• Psychological support
• Careful observation for erythema (document locations), hair loss, skin injury, mucositis, parotitis, weight loss, or fever
• Confirmation of initial dose estimate, using chromosome aberration cytogenetic bioassay when possible (Although resource-intensive, this is the best method of dose assessment following acute exposures.)
• Consultation with experts in radiation accident management (CDC, 2005rb)

Internal Contamination

Consider internal contamination if high survey readings persist following decontamination. Internal contamination generally does not cause early symptoms. Nose or mouth contamination may indicate inhalation or ingestion.

To check for internal contamination:

• Assessment may include analysis of urine, blood, and fecal samples or whole-body counts. Consult with radiation experts.
• Radiation experts may recommend early administration of radionuclide-specific decorporation agents such as Prussian blue, DTPA, or bicarbonate.
• Gastric lavage, antacids, and cathartics assist in clearing ingested contaminants. (CDC, 2005ra)

Psychosocial Issues

In urban areas, hundreds to thousands may seek care. Most will self-refer to the nearest hospital. While many may need decontamination, others may seek radiologic screening even though not contaminated. Many simply seek reassurance. Mental health professionals should always be members of the response team and available in any first-receiver facility to provide such support.

When evaluating patients, healthcare workers need to understand that psychogenic symptoms, such as nausea or vomiting, may manifest. Keep in mind that vomiting due to radiation exposure is usually recurrent rather than episodic.

Have radiation exposure fact sheets available for patients and families and remember that pregnant patients require special counseling. It is likely that separate areas for radiation screening and counseling will be needed for patients with minimal risk of exposure or injury (CDC, 2005ra).

Modern chemical warfare can be traced back to World War I, when the German military used chlorine gas in defiance of a longstanding international agreement against the use of poisons in war. Since that time there has been research and stockpiling of chemicals by many countries, but mutual deterrence has generally prevailed. In 1995 a quasi-religious group released sarin in the Tokyo subway system, resulting in the deaths of twelve people; however, despite this group's many financial and technical resources, the release was still considered a "crude usage" of the chemical (CNS, 2007a). There have been a few war-related uses, notably the gassing of the Kurds in northern Iraq by the Iraqi army in the late 1980s.

CHEMICAL WEAPONS

Chemical weapons agents are either nonpersistent or persistent. Nonpersistent agents dissipate within a few hours and are most threatening to the lungs. Persistent agents may take up to one month to dissipate if they have been deposited on soil, vegetation, or objects. They are most threatening to the skin.

Chemical agents of interest to terrorists range from warfare agents to toxic chemicals commonly used in industry. Criteria for determining the likely choice of chemical agents include:

• Chemical agents already known to be used as weaponry
• Availability of chemical agents to potential terrorists
• Chemical agents likely to cause major morbidity or mortality
• Potential of agents for causing public panic and social disruption
• Agents that require special action for public health preparedness

Chemical Agents

The following lists include categories of chemical weapons agents and some representative compounds. Nerve agents are the fastest acting, the most deadly, and the most likely to be used by terrorists (CNS, 2007a). However, terrorist activity may utilize common substances, like the explosive compound of fertilizer and fuel called ANFO (ammonium nitrate/fuel oil) that was used in the Oklahoma City bombings.

Chemical weapons agents generally fall into one of the following groups:

• Blister agents, or vesicants (sulfur mustard, lewisite)
• Choking agents (chlorine, phosgene)
• Blood agents (cyanogen chloride)
• Nerve agents (sarin, VX) (CNS, 2007a)

Additional categories of chemical agents include:

• Heavy metals (arsenic, lead, mercury)
• Volatile toxins (benzene, chloroform, trihalomethanes)
• Incapacitating agents (BZ)
• Pesticides, persistent and nonpersistent
• Dioxins, furans, and polychlorinated biphenyls (PCBs)
• Explosive nitro compounds and oxidizers (ammonium nitrate combined with fuel oil)
• Flammable industrial gases and liquids (gasoline, propane)
• Poison industrial gases, liquids, and solids (cyanides, nitriles)
• Corrosive industrial acids and bases (nitric acid, sulfuric acid) (CDC, 2000)

Delivery Methods

Chemical weapons agents require a delivery method, generally one of the following:

• Spraying (aerosolized)
• Exploding a device
• Contaminating food or water
•  Attacking or sabotaging a chemical facility (CNS, 2008)

COVERT CHEMICAL RELEASE

Since September 11, 2001, concern has increased about potential terrorist attacks involving the use of chemical agents. In addition, recent cases involving intentional or inadvertent contamination of food with chemicals have highlighted the need for healthcare providers and public health officials to be alert for patients in their communities who have signs and symptoms consistent with chemical exposures (CDC, 2003b).

Intentional release of chemical agents may be an overt event, one whose nature reveals itself, such as release of a nerve agent in a subway or a large explosion of a chemical container. On the other hand, a chemical release might be a covert event, an unrecognized release in which the presence of ill persons could be the first sign of an exposure, such as deliberate contamination of food, water, or a consumer product.

To increase the likelihood that healthcare providers recognize a chemical release–related illness, and that public health authorities will implement the appropriate emergency response and public health actions, the CDC has identified examples of chemical-induced illness (Table 1, below) and created appropriate guidance for healthcare providers and public health personnel (CDC, 2003b).

The CDC recognizes that the covert release of a chemical agent might not be easily identified, for at least five reasons:

1. Symptoms of exposure to some chemical agents (eg, ricin) might be similar to those of common diseases (eg, gastroenteritis).
2. Immediate symptoms of certain chemical exposures might be nonexistent or mild despite the risk for long-term effects (eg, neurocognitive impairment from dimethyl mercury, teratogenicity from isotretinoin, or cancer from aflatoxin).
3. Exposure to contaminated food, water, or consumer products might result in reports of illness to healthcare providers over a long period and in various locations.
4. Persons exposed to two or more agents might have symptoms not suggestive of any one chemical agent (ie, a mixed clinical presentation).
5. Healthcare providers might be less familiar with clinical presentations suggesting exposure to chemical agents than they are with illnesses that are treated frequently (CDC, 2003b).

Epidemiologic Cues

When there has been a covert release of a chemical agent, identifying the situation may depend on alert healthcare professionals as they begin to see victims of the release. Epidemiologic cues that might suggest a covert release include:

1. An unusual increase in the number of patients seeking care for potential chemical release–related illness
2. Unexplained deaths among young or healthy persons
3. Emission of unexplained odors by patients
4. Clusters of illness in persons who have common characteristics, such as drinking water from the same source
5. Rapid onset of symptoms after an exposure to a potentially contaminated medium (eg, paresthesias and vomiting within minutes of eating a meal)
6. Unexplained death of plants, fish, or animals (domestic or wild)
7. A syndrome (ie, a constellation of clinical signs and symptoms in patients) suggesting a disease associated commonly with a known chemical exposure (eg, neurologic signs or pinpoint pupils in eyes of patients with a gastroenteritis-like syndrome or acidosis in patients with altered mental status)

Identifying Specific Agents

Because various chemical agents could be used as covert weapons, the actual clinical syndrome varies depending on the type of agent, the amount and concentration of the chemical, and the route of the exposure. However, some clinical presentations may be more common with a covert chemical release. Certain syndromes are associated with groups of chemical agents with similar toxic properties that have been used previously, have high toxicity, or are easily available (Table 1) (CDC, 2003b).

TABLE 1

CLINICAL SYNDROMES AND POTENTIAL CHEMICAL ETIOLOGIES*

Category	Clinical syndrome	Potential chemical etiology
Cholinergic crisis	Salivation, diarrhea, lacrimation, bronchorrhea, diaphoresis, and/or urination Miosis, fasciculations, weakness, bradycardia or tachycardia, hypotension or hypertension, altered mental status, and/or seizures	Nicotine** Organophosphate insecticides**—decreased acetylcholinesterase activity Carbamate insecticides Medicinal carbamates (eg, physostigmine)
Generalized muscle rigidity	Seizure-like, generalized muscle contractions or painful spasms (neck and limbs) and, usually, tachycardia and hypertension	Strychnine—intact sensorium
Oropharyngeal pain and ulcerations	Lip, mouth, and pharyngeal ulcerations and burning pain	Paraquat**—dyspnea and hemoptysis secondary to pulmonary edema or hemorrhage; can progress to pulmonary fibrosis over days to weeks Diquat Caustics (acids, alkalis) Inorganic mercuric salts Mustards (sulfur)
Cellular hypoxia	Mild: nausea, vomiting, and headache Severe: altered mental status, dyspnea, hypotension, seizures, and metabolic acidosis	Cyanide** (hydrogen cyanide gas, sodium cyanide)—bitter almond odor*** Sodium monofluoroacetate (SMFA)**—hypocalcemia or hypokalemia Carbon monoxide Hydrogen sulfide Sodium azide Methemoglobin-causing agents
Peripheral neuropathy and/or neurocognitive effects	Peripheral neuropathy signs and symptoms: muscle weakness and atrophy, "glove and stocking" sensory loss, and depressed or absent deep-tendon reflexes Neurocognitive effects: memory loss, delirium, ataxia, and/or encephalopathy	Mercury (organic)**—visual disturbances, paresthesias, and/or ataxia Arsenic (inorganic)**—delirium and/or peripheral neuropathy Thallium—delirium and/or peripheral neuropathy Lead—encephalopathy Acrylamide—encephalopathy and/or peripheral neuropathy
Severe gastrointestinal illness, dehydration	Abdominal pain, vomiting, profuse diarrhea (possibly bloody), and hypotension, possibly followed by multisystem organ failure	Arsenic** Ricin**—inhalation an additional route of exposure; severe respiratory illness possible Colchicine Barium—hypokalemia common
*Not intended as a complete differential diagnosis for each syndrome or as a list of all chemicals that might be used in a covert chemical release. **Potential agents for a covert chemical release based on historic use (i.e., intentional or inadvertent use), high toxicity, and/or ease of availability. ***Unreliable sign. Source: (CDC, 2003b).

It is likely that a covert chemical release would be first recognized by healthcare providers, public health agencies, and poison control centers as they become aware of patterns while assessing illness and treating patients. Familiarity of healthcare professionals with the general characteristics of a covert chemical release, plus recognition of epidemiologic clues and related clinical syndromes, could reduce morbidity and mortality as these workers implement the appropriate emergency response.

Public health agencies and healthcare providers render the most appropriate, timely, and clinically relevant treatment possible by using treatment modalities based on syndromic categories (eg, burns, respiratory depression, neurologic damage, shock). Because of the hundreds of new chemicals introduced globally each month, it is more effective to treat exposed persons by clinical syndrome rather than specific agent (CDC, 2003b; CDC, 2000).

State and local health departments need to educate healthcare providers to recognize unusual illnesses that might indicate release of a chemical agent. Strategies for responding to intentional chemical releases include:

1. Providing information or reminders to healthcare providers and clinical laboratories
2. Encouraging reporting of acute poisonings to local poison control centers, which can guide patient management and facilitate notification of the proper health agencies, and to the local or state health department
3. Initiating surveillance for incidents that potentially involve the covert release of a chemical agent
4. Implementing the capacity to receive and investigate any report of such an event
5. Implementing appropriate protocols, including potentially accessing the Laboratory Response Network for Bioterrorism, to collect and transport specimens and to store them appropriately before laboratory analysis
6. Reporting immediately to CDC and local law enforcement if the results of an investigation suggest the intentional release of a chemical agent
7. Requesting CDC assistance when necessary (CDC, 2003b).

RECOGNIZING SOME SPECIFIC CHEMICAL AGENTS

The Centers for Disease Control (CDC) provide many reference materials for recognizing and treating the effects of all types of chemical compounds (see References at the end of this course). Included among these materials are "reference cards" for dozens of individual chemical compounds. These cards include essential information for emergency and hospital personnel, including the type of personal protective clothing/equipment needed when treating victims. Hospitals and other healthcare agencies should have this information on file for immediate access by staff in case of incident.

Below are the CDC guidelines for two of the common categories of chemical agents. These guidelines provide information on recognizing signs and symptoms, initial treatment, and alternative diagnoses. Remember that the details will differ for other agents.

While personal protective equipment and clothing is necessary for treating virtually anyone who has been exposed to a chemical agent, specifics vary according to the agent involved. It is critical to have this information on hand and for staff to be trained to consult it.

Vesicant (Blister Agent) Poisoning

Vesicants, also referred to as "blister agents," were the most commonly used chemical warfare agents during World War I. Likely routes of exposure are inhalation, dermal contact, and ocular contact. Vesicants are highly reactive chemicals that combine with proteins, DNA, and other cellular components to result in cellular changes immediately after exposure. Vesicants include distilled mustard (HD), mustard gas (H), lewisite, mustard/lewisite, mustard/T, nitrogen mustard, phosgene oxime, sesqui mustard, and sulfur mustard.

Depending on the vesicant, clinical effects may occur immediately (eg, phosgene oxime, lewisite) or may be delayed for 2 to 24 hours (eg, mustards). Following exposure, the most commonly encountered clinical effects include dermal (skin erythema, blistering), respiratory (pharyngitis, cough, dyspnea), ocular (conjunctivitis, burns), and gastrointestinal (nausea, vomiting).

The amount and route of exposure to the vesicant, the type of vesicant, and the premorbid condition of the person exposed contribute to the time of onset and the severity of illness. For example, ingestion of a vesicant leads to gastrointestinal symptoms more prominent than those that would result from inhalation exposure to the same dose and type of vesicant.

SIGNS AND SYMPTOMS

The following is a more comprehensive list of signs and symptoms that may be encountered in a person exposed to a vesicant. Signs and symptoms are not listed in order of presentation or specificity. Also, partial presentations (an absence of some of the following signs/symptoms) do not necessarily imply less severe disease.

Respiratory signs and symptoms include:

• Clear rhinorrhea
• Nasal irritation/pain
• Sore throat
• Cough
• Dyspnea (shortness of breath)
• Chest tightness
• Tachypnea
• Hemoptysis

Dermal signs and symptoms include:

• Itching
• Immediate blanching (phosgene oxime)
• Erythema (immediate with lewisite and phosgene oxime, may be delayed for 2 to 24 hours with mustards)
• Blisters (within 1 hour with phosgene oxime, delayed for 2 to 12 hours with lewisite, delayed for 2 to 24 hours with mustards)
• Necrosis and eschar (over a period of 7 to 10 days)

Ocular signs and symptoms include:

• Conjunctivitis
• Lacrimation
• Eye pain/burning
• Photophobia
• Blurred vision
• Eyelid edema
• Corneal ulceration
• Blindness

Cardiovascular signs include:

• Hypotension (with high-dose exposure to lewisite)
• Atrioventricular block and cardiac arrest (with high-dose exposure)

Gastrointestinal signs and symptoms (prominent if ingestion is a route of exposure) include:

• Abdominal pain
• Nausea and vomiting
• Hematemesis
• Diarrhea (sometimes bloody)

Central nervous system signs and symptoms (with exposure to high doses) include:

• Tremors
• Convulsions
• Ataxia
• Coma

LABORATORY FINDINGS

Although it is a nonspecific finding, leukopenia can indicate vesicant exposure. It usually begins 3 to 5 days after exposure. With a white blood cell count <500, the prognosis is poor.

DIFFERENTIAL DIAGNOSIS

• Barbiturates
• Chemotherapeutic agents
• Carbon monoxide
• Stevens-Johnson syndrome
• Staphylococcus scalded skin syndrome
• Toxic epidermal necrolysis
• Bullous pemphigoid
• Pemphigus vulgaris
• Other chemical burns (eg, with strong acids, bases, corrosives)

Note: The actual clinical manifestations of a vesicant exposure may be more variable than the syndrome described above (CDC, 2005ca).

Nerve Agents and Pesticides

Nerve agents have the same mechanism of action as organophosphate (OP) pesticides. They are potent inhibitors of acetylcholinesterase. Inhibition of acetylcholinesterase leads to an accumulation of acetylcholine in the central and peripheral nervous system. Excess acetylcholine produces a predictable cholinergic syndrome consisting of copious respiratory and oral secretions, diarrhea and vomiting, sweating, altered mental status, autonomic instability, and generalized weakness that can progress to paralysis and respiratory arrest.

The amount and route of exposure to the nerve agent or OP pesticide, the type of agent or pesticide, and the premorbid condition of the exposed person contribute to the time of onset and the severity of illness. For example, inhalation of a nerve agent or an OP pesticide leads to a quicker onset of poisoning with more severe symptoms than dermal exposure, given the same amount of agent.

SIGNS AND SYMPTOMS

The following is a more comprehensive list of signs and symptoms that may be encountered in a person exposed to a nerve agent or OP pesticide. Signs and symptoms are not listed in order of presentation or specificity. Also, partial presentations (an absence of some of the following signs/symptoms) do not necessarily imply less severe disease.

Central nervous system signs and symptoms include:

• Miosis (unilateral or bilateral)
• Headache
• Restlessness
• Convulsions
• Loss of consciousness
• Coma

Respiratory signs and symptoms include:

• Rhinorrhea (perfuse watery runny nose)
• Bronchorrhea (excessive bronchial secretions)
• Wheezing
• Dyspnea (shortness of breath)
• Chest tightness
• Hyperpnea (increased respiratory rate/depth)—early
• Bradypnea (decreased respiratory rate)—late

Cardiovascular signs include:

• Tachycardia (increased heart rate)—early
• Hypertension (high blood pressure)—early
• Bradycardia (decreased heart rate)—late
• Hypotension (low blood pressure)—late
• Dysrhythmias (prolonged QT on ECG, ventricular tachycardia)

Gastrointestinal signs and symptoms include:

• Abdominal pain
• Nausea and vomiting
• Diarrhea
• Urinary incontinence, frequency

Musculoskeletal signs and symptoms include:

• Weakness (may progress to paralysis)
• Fasciculations (local or generalized)

Skin and mucous membrane signs and symptoms include:

• Profuse sweating (local or generalized)
• Lacrimation (tear formation)
• Conjunctival injection

LABORATORY FINDINGS

There may be decreased plasma or red blood cell (RBC) cholinesterase activity. Limitations:

• Wide normal range for enzyme activity makes interpretation difficult without a baseline measurement.
• Cholinesterase activity correlates poorly with severity of local effects after vapor exposures.
• Plasma or RBC cholinesterase may be disproportionately inhibited depending on the particular nerve agent, amount of exposure, and time interval since exposure.

Interpreting cholinesterase activity:

• Plasma cholinesterase
• Usually declines faster than RBC cholinesterase
• Is easier to assay than RBC cholinesterase
• Regenerates faster than RBC cholinesterase
• May have a day-to-day variation in enzyme activity as high as 20%
• Is less specific than RBC cholinesterase
• Can show false depression from liver disease, malnutrition, pregnancy, genetic deficiency, or drugs (eg, codeine, morphine, cocaine, succinylcholine).
• Red blood cell cholinesterase
• Is a better reflection of CNS cholinesterase activity;
• Is more specific test than plasma cholinesterase;
• May have a day-to-day variation in enzyme activity as high as 10%; and
• Can show false depression from antimalarial therapy or pernicious anemia.

DIFFERENTIAL DIAGNOSIS

• Carbamate insecticides
• Medicinal carbamates (eg, pyridostigmine, neostigmine, physostigmine)
• Cholinomimetic compounds (eg, pilocarpine, methacholine, bethanechol)
• Nicotine alkaloids (eg, nicotine, coniine)
• Muscarine-containing mushrooms
• Neuromuscular blocking drugs (eg, atracurium, vecuronium)

Note: The actual clinical manifestations of an exposure to a nerve agent or an OP pesticide may be more variable than the syndrome described in this document (CDC, 2005cb).

Biological terrorism, or bioterrorism, is the act of using bacteria, toxins, or viruses to cause human disease, to harm people, or to elicit widespread fear or intimidation for political or ideological goals (NIH, 2002). Biological warfare (BW) agents are microorganisms that infect humans, livestock, or crops and cause an incapacitating or fatal disease. Symptoms of illness do not appear immediately but only after a delay, or "incubation period," that may last for days to weeks (CNS, 2007a).

From a scientific and medical perspective, bioterrorism can be viewed as a variation of the problem of emerging infectious diseases, the only difference being that increased virulence or intentional release are deliberate acts. The United States public health system and primary healthcare providers must be prepared to address various biological agents, including pathogens that are rarely seen in this country.

COVERT vs. OVERT BIOTERRORISM

The intentional release of biological agents can be either covert or overt. A covert release is unannounced and hidden, and may go unnoticed for days or even weeks. The presence of ill persons may be the first sign of a release, and the infected persons may have inadvertently infected others. An infected person may seek medical care anywhere within the healthcare system, possibly at a distance from the release area.

An overt release is immediately apparent and may even be announced. In an overt release, the healthcare system and public health officials may be overwhelmed by requests for information and treatment. Hospitals, clinics, emergency responders, and communication systems will be pressed into immediate service. An overt release has the potential to cause widespread panic.

Whether the release is covert or overt, healthcare providers need to be alert to illness patterns and diagnostic clues that indicate an unusual infectious disease outbreak which could be associated with intentional release of a biological agent. Healthcare professionals need to be on the outlook for increases in unexpected or unexplained illnesses and know how to activate the public health response system if an outbreak is suspected (CDC, 2001). Well-trained and educated first responders, first receivers (hospital-based emergency staff), and public health personnel are essential to an organized and successful response.

IMPROVING RESPONSE TO BIOLOGICALLY INDUCED ILLNESS

Healthcare providers, clinical laboratory personnel, infection control professionals, and public health departments play critical and complementary roles in the recognition and response to illness caused by the intentional release of biological agents. Syndrome descriptions, epidemiologic clues, and laboratory recommendations provide basic guidance that can improve recognition of these events (CDC, 2001).

Since 9/11, state and local health departments have initiated activities to improve recognition, reporting, and response, ranging from enhancing communications to conducting special surveillance projects. This includes active tracking for changes in the number of hospital admissions, emergency department visits, and occurrence of specific syndromes. Bioterrorism preparedness activities and work with emerging infectious diseases have helped public health agencies prepare for the intentional release of a biological agent (CDC, 2001).

Recognizing Clinical Syndromes

Work continues on syndromic surveillance projects and the CDC maintains current data on this research. The term syndromic surveillance means watching for health-related data that signal sufficient probability of a case or an outbreak to warrant further public health response. Historically, syndromic surveillance was used in investigating potential cases, but its utility for detecting outbreaks associated with bioterrorism is increasingly being explored by public health officials (CDC, 2004b; CDC, 2006b).

The release of a biological agent may not have an immediate impact because of the delay between exposure and onset of illness, and because outbreaks associated with intentional releases may resemble naturally occurring ones. Nevertheless, healthcare workers should be familiar with indications of intentional release of a biological agent and know when, and to whom, to report a suspected outbreak.

These indications include unusual clustering of illness, patients presenting with clinical signs and symptoms that suggest an infectious disease outbreak, unusual age distribution for common diseases, and a large number of cases of acute flaccid paralysis with prominent bulbar palsies, which is suggestive of a release of botulinum toxin (CDC, 2001).

The most common features of an outbreak caused by bioterrorist agents include:

• Rapid increase (hours to days) in the number of previously healthy persons with similar symptoms seeking medical treatment
• Cluster of previously healthy persons with similar symptoms who live, work, or recreate in a common geographical area
• An unusual clinical presentation
• Increase in reports of dead animals
• Lower incident rates in individuals who are protected (eg, confined to home with no exposure to large crowds)
• Increase in number of patients who expire within 72 hours after admission to the hospital
• Any person with a history of recent (past 2–4 weeks) travel to a foreign country who presents with symptoms of high fever, rigors, delirium, rash not characteristic of measles or chickenpox, extreme myalgias, prostration, shock, diffuse hemorrhagic lesions or petechiae; and/or extreme dehydration due to vomiting or diarrhea with or without blood loss (TIH, 2004).

A number of factors affect the potential public health impact of an intentionally released biological agent. The quality of the infectious agent and the infectious dose needed to cause an outbreak will affect the type and scope of the medical response. The incubation period of a disease organism can be anywhere from 1 to 42 days, making it potentially difficult to pinpoint the time and location of the release (CNS, 2007a).

Mortality and duration are important factors to consider from a public health perspective (CNS, 2007a). Plague has a rapid onset and is potentially fatal within 12 to 24 hours if untreated. Botulism toxin has a rapid onset and requires immediate supportive treatment. Smallpox can be treated effectively with a vaccination within 2 to 3 days of symptom onset.

How long an organism remains in the environment and how widely it was disbursed impacts the public health response (CNS, 2007a). Most viruses and bacteria die shortly after exposure to air but some bacterial spores such as anthrax may be able to survive for several hours or longer.

Finally, the contagiousness of an organism and the availability of a vaccine or medical treatment are of primary concern (CNS, 2007a). Smallpox and plague are highly contagious and have the potential for causing widespread panic. In the case of smallpox, which was believed to be eradicated, not enough vaccine exists should a widespread outbreak occur. Anthrax and plague, despite their potential for causing serious illness and death, are effectively treated with antibiotics.

CATEGORIES OF DISEASES AND BIOLOGICAL AGENTS

Any nation or group with an advanced pharmaceutical industry can produce biological weapons. More than thirty microbes have been identified as having potential for use as a biological weapon. The CDC defines three categories of diseases and biological agents based on their ease of dissemination, morbidity and mortality, potential for panic and social disruption, and requirements for public health preparedness (CDC, 2007).

Category A Diseases or Agents

Category A diseases or agents are high priority and include organisms that pose a risk to national security. They can be mass-produced, transported, and disseminated with relative ease.

Category A diseases or agents:

• Are easily disseminated or transmitted from person to person.
• Cause high mortality rates.
• Have the potential for major public health impact.
• May cause panic and social disruption.
• Require special action for public health preparedness. (CDC, 2007).

Category A diseases or agents include:

• Anthrax (Bacillus anthracis)
• Botulism (Clostridium botulinum toxin)
• Plague (Yersinia pestis)
• Smallpox (variola major)
• Tularemia (Francisella tularensis)
• Viral hemorrhagic fevers (filoviruses [eg, Ebola, Marburg], and arenaviruses [eg, Lassa, Machupo]) (CDC, 2007).

Category B Diseases or Agents

Category B diseases or agents are the second highest priority and:

• Are moderately easy to disseminate.
• Result in moderate morbidity rates and low mortality rates.
• Require specific enhancements of CDC's diagnostic capacity and enhanced disease surveillance. (CDC, 2007).

Category B diseases or agents include:

• Brucellosis (Brucella species)
• Epsilon toxin of Clostridium perfringens
• Food safety threats (eg, Salmonella species, Escherichia coli O157:H7, and Shigella)
• Glanders (Burkholderia mallei)
• Melioidosis (Burkholderia pseudomallei)
• Psittacosis (Chlamydia psittaci)
• Q fever (Coxiella burnetii)
• Ricin toxin from Ricinus communis (castor beans)
• Staphylococcal enterotoxin B
• Typhus fever (Rickettsia prowazekii)
• Viral encephalitis (alphaviruses [eg, Venezuelan equine encephalitis, eastern and western equine encephalitis])
• Water safety threats (eg, Vibrio cholerae, Cryptosporidium parvum) (CDC, 2007).

Category C Diseases or Agents

Category C diseases or agents are the third highest priority and include emerging pathogens that could be engineered for mass dissemination in the future because of availability, ease of production and dissemination, and potential for high morbidity and mortality rates and major health impact.

Category C diseases or agents include emerging infectious diseases such as Nipah virus and hantavirus (CDC, 2007).

CLINICAL FEATURES OF HIGH-PRIORITY AGENTS

Four category A diseases have been the focus of the CDC's efforts to educate the healthcare community about bioterrorism potential: anthrax, botulism, plague, and smallpox. The CDC does not prioritize these agents in any order of importance or likelihood of use. Other agents with bioterrorism potential include those that cause tularemia and viral hemorrhagic fevers (category A), brucellosis, Q fever, viral encephalitis, and disease associated with staphylococcal enterotoxin B (category B). Other important category B agents include any organism that threatens the water or food supply.

Anthrax

Anthrax is a bacterium that forms spores, which are the infectious component of the organism. In the absence of an intentional release, anthrax infection is extremely rare. In nature, anthrax occurs in sheep, cattle, horses, and pigs. Anthrax commonly causes disease in herbivores, which are infected after eating soil contaminated with spores (Inglesby et al., 2002). Spores are transmitted to humans by handling or ingesting contaminated animals or animal products or by handling spore-infested soil. Inoculation is through broken skin and mucous membranes, by inhalation, or more rarely by ingestion (Tierney, McPhee & Papadakis, 2004). There are three clinical forms of anthrax: inhalation, cutaneous, and gastrointestinal (Table 2, below).

Inhalation anthrax is rare but accounts for the majority of anthrax fatalities. There have been no naturally occurring cases of inhalation anthrax reported in the United States since 1976. Inhalation anthrax develops in two stages. The first stage occurs on average 10 days after exposure, although initial symptoms can be delayed for up to 6 weeks after exposure. In the first stage, nonspecific flu-like symptoms, fever, dyspnea, cough, congestion, and anterior chest discomfort occur. Approximately 2 to 4 days after initial symptoms—sometimes after a brief period of improvement—respiratory failure, sepsis, and hemodynamic collapse occur. Thoracic edema and a widened mediastinum may be present on chest radiograph. Gram-positive bacilli can grow on blood culture, usually 2 to 3 days after onset of illness. Inhalation anthrax is not contagious person to person. Treatment is for 60 days with ciprofloxacin, rifampin, and clindamycin in the intensive-care unit.

Cutaneous anthrax is the most commonly occurring form of anthrax worldwide, with approximately two thousand cases reported annually. If left untreated, there is an approximately 20% fatality rate, which drops to less than 1% if treated with ciprofloxacin, doxycycline, or penicillin for 60 days. Symptoms appear within two weeks of exposure. Cutaneous anthrax infection occurs when the anthrax spore comes into contact with the skin—particularly on exposed areas of the hands, arms, or face. An area of local edema becomes a pruritic macule or papule, which enlarges and ulcerates after 1 to 2 days. Small, 1- to 3-mm vesicles may surround the ulcer. A painless, depressed, black eschar, usually with surrounding local edema, subsequently develops. The syndrome also may include lymphangitis and painful lymphadenopathy (CDC, 2001).

Gastrointestinal anthrax, which has not been reported in the United States, occurs 2 to 5 days after ingesting the anthrax spore in contaminated meat. As with the other forms of anthrax, fever is present in addition to diffuse abdominal pain and tenderness, nausea, and vomiting. Ulcerative lesions may cause bowel perforation (Tierney et al., 2004). As with the other forms of anthrax, doxycycline, ciprofloxacin (or another antibiotic in its class) and amoxicillin are used for 60 days for treatment.

TABLE 2

ANTHRAX

Type of anthrax	Signs and symptoms
Inhalation anthrax	nonspecific flu-like symptoms fever dyspnea cough congestion anterior chest discomfort
Cutaneous anthrax	local edema becomes a pruritic macule or papule, which enlarges and ulcerates after 1–2 days lymphangitis and painful lymphadenopathy
Gastrointestinal anthrax	fever diffuse abdominal pain and tenderness nausea vomiting bloody diarrhea ulcerative lesions may cause bowel perforation

"Weapons grade" anthrax (high spore count, uniform spore size, and low electrostatic charge), of the type used in the anthrax attacks in the United States following the destruction of the World Trade Center in New York, is difficult and expensive to produce. By contrast, lower-grade anthrax is more easily obtained from livestock vaccination programs but is not a significant risk to humans (Inglesby et al., 2002).

Botulism

Botulism neurotoxin is an extremely potent organism found in soil that causes respiratory paralysis and death if left untreated. Less than 1 microgram causes fatality in adults. The spore is formed by Clostridium botulinum and causes paralysis by inhibiting the release of acetycholine at the neuromuscular junction. There are 30 to 50 case of foodborne botulism reported each year in the United States.

Clinical features in adults include symmetric cranial neuropathies, such as drooping eyelids, weakened jaw clench, difficulty swallowing or speaking, blurred vision or diplopia, symmetric descending weakness in a proximal to distal pattern, and respiratory dysfunction from respiratory muscle paralysis or upper-airway obstruction without sensory deficits. In infants, symptoms can include loss of head control and limb weakness, respiratory distress, constipation, lethargy, and loss of gag reflex.

Food-borne botulism can be contracted by ingesting botulism from infected canned, smoked, or vacuum-packed foods. Inhalational botulism has a similar clinical presentation; however, the gastrointestinal symptoms that accompany foodborne botulism may be absent (CDC, 2001).

Treatment is supportive, and in the case of respiratory failure mechanical ventilation may be necessary. Antitoxin is effective in reducing the severity of symptoms, if administered early, A supply of antitoxin against botulism is maintained by the CDC and state health departments should contact CDC to arrange for a clinical consultation by phone, and (if indicated) the release of the antitoxin. Botulism can be prevented by the administration of neutralizing antibody in the bloodstream. Passive immunity can be provided by equine botulinum antitoxin or by specific human hyperimmune globulin, while endogenous immunity can be induced by immunization with botulinum toxoid (CDC, 2006b).

Plague (Yersinia pestis)

Plague is an acute and potentially fatal bacterial infection that affects humans and animals and is caused by Y. pestis. Plague usually presents as one of five principal clinical syndromes: bubonic, pneumonic, septicemic, plague meningitis, or pharyngeal. Plague is a naturally occurring disease that has been endemic in the United States since 1900. Approximately 5 to 15 cases occur per year, with the greatest concentration of cases in Arizona, Colorado, and New Mexico (CDC, 2004a).

An immediate and coordinated public health and medical response would be required in the event of the intentional use of plague. Therefore, any case of plague should be reported to the state health department immediately. Reporting is especially important when a case of plague occurs outside of a typically affected area (CDC, 2004a).

With bubonic plague, the infection is transmitted by the bite of an infected flea or exposure to infected material through a break in the skin. Bubonic plague cannot be transmitted from person to person. If bubonic plague is not treated, the bacteria can spread through the bloodstream and infect the lungs, causing a secondary infection of pneumonic or septicemic plague (CDC, 2004a).

Pneumonic plague is a pulmonary infection that occurs upon inhalation of plague bacteria. Pneumonic plague can be transmitted person to person through respiratory droplets with direct close contact and, without early treatment, in less than 24 hours pneumonic plague almost universally leads to respiratory failure, shock, and rapid death (CDC, 2004a).

Infection via inhalation of infective respiratory droplets or aerosols is rare with naturally occurring plague in the United States, but is the most likely route of transmission in a bioterrorist event. If Y. pestis were to be used as a bioweapon, it would be most dangerous if released as an aerosol. An aerosol release would be expected to result in an outbreak of the pneumonic form of plague and it may also cause the less common pharyngeal plague and ocular plague (CDC, 2004a).

The primary form of septicemic plague results from direct inoculation and multiplication of plague bacilli in the bloodstream, while the secondary form is a development of untreated pneumonic or bubonic plague (CDC, 2004a).

CLINICAL FEATURES

BUBONIC PLAGUE

• Incubation period: 2 to 6 days.
• Symptoms
• Lymphadenopathy and fever are both early symptoms of bubonic plague.
• Patients develop buboes, which are grossly enlarged, extremely tender lymph nodes draining at the respective site of inoculation.
• Progression of disease. If bubonic plague is not treated, the bacteria can spread through the bloodstream, causing septicemia, or it can infect the lungs, causing a secondary case of pneumonic plague. Rarely, it can progress to meningitis. (CDC, 2004a).

PNEUMONIC PLAGUE

• Incubation period: 2 to 4 days with range of 1 to 6 days.
• Symptoms
• Acute onset of fever, chills, malaise, and myalgias associated with progressive lethargy.
• A productive cough of copious watery mucoid sputum that may be bloody.
• Associated chest pain and increasing dyspnea.
• Progression of disease. As the disease progresses, adult respiratory distress syndrome (ARDS) characterized by refractory pulmonary edema may occur. Signs of shock, including hypotension and eventual multi-organ failure, may also occur. Without early detection and treatment, in less than 24 hours pneumonic plague is almost universally fatal (CDC, 2004a).

SEPTICEMIC PLAGUE

• Incubation period. Occurs when plague bacteria multiply in the blood. Most commonly, septicemic plague presents as a complication of pneumonic or bubonic plague, but primary septicemic plague can occur.
• Symptoms. Acute onset of fever, chills, prostration, abdominal pain, nausea, and vomiting.
• Progression of disease. As the disease progresses, purpura may develop, as well as possible disseminated intravascular coagulation (DIC). Eventually, hypotension and other signs of shock appear. Septicemic plague is often fatal even when treated (CDC, 2004a).

Smallpox (Variola)

Smallpox is a highly infectious and virulent disease caused by the variola virus. It is marked by fever and a distinctive, progressive skin rash. The name smallpox is derived partly from the Latin word for "spotted" and refers to the raised bumps that appear on the face and body of an infected person. There is no specific treatment for smallpox, and the only prevention is vaccination.

There are two clinical forms of smallpox: variola major and variola minor. Variola major is the most common and most severe form of smallpox. It produces an extensive rash and high fever. Historically, variola major has an overall fatality rate of about 30%. Variola minor is a less-common and less-severe form of smallpox, with death rates historically of 1% or less.

Human-to-human transmission normally occurs by inhalation of large virus-containing airborne droplets of saliva from an infected person. Infectious virus particles are released by the sloughing of oropharyngeal lesions. Smallpox can also be spread through direct contact with infected bodily fluids or contaminated objects such as bedding or clothing.

The acute clinical symptoms of smallpox resemble other acute viral illnesses, such as influenza, beginning with a 2- to 4-day nonspecific prodrome of fever and myalgias before rash onset. Several clinical features can help clinicians differentiate varicella (chickenpox) from smallpox. The rash of varicella is most prominent on the trunk and develops in successive groups of lesions over several days, resulting in lesions in various stages of development and resolution. In comparison, the vesicular/pustular rash of smallpox is typically most prominent on the face and extremities, and lesions develop at the same time (CDC, 2001).

The only weapons against smallpox are vaccination and patient isolation. Vaccination before exposure, or within 2 to 3 days after exposure, affords almost complete protection against disease. Vaccination as late as 4 to 5 days after exposure may protect against death. The smallpox vaccine is derived from the vaccinia virus, which is another pox-type virus. Vaccinia is related to smallpox, but is milder and does not contain the smallpox virus. The vaccinia vaccine helps the body develop immunity to smallpox.

BEST PRACTICES FOR FIRST RECEIVERS

Healthcare workers risk occupational exposures to biologic materials when a hospital receives contaminated patients, particularly during mass-casualty events. Hospital employees, termed first receivers, work at a site removed from where the hazardous release occurred. This means that their exposures are limited to the substances transported to the hospital on the skin, hair, clothing, or personal effects of the victims. The location and limited source of contaminants distinguishes first receivers from first responders such as firefighters, law enforcement, and ambulance service personnel, who typically respond to the incident site (OSHA, 2005).

Worst-case scenarios take into account challenges associated with communication, resources, and victims. During mass-casualty emergencies, hospitals can anticipate little or no warning before victims begin arriving. First receivers can anticipate that information regarding the hazardous agents may not be available immediately. Hospitals can also anticipate a large number of self-referred victims (as many as 80% of the total number of victims) and should assume victims will not have been decontaminated prior to arriving at the hospital (OSHA, 2005).

An employee's role plus the hazards that employee might encounter dictate the level of training that must be provided to any individual first receiver. Selection of personal protective equipment (PPE) must be based on a hazard assessment that carefully considers both of these factors, along with the steps taken to minimize the extent of the employee's contact with hazardous substances (OSHA, 2005). Surge capacity, triage, decontamination, security, and disposal of contaminated wastewater must also be addressed.

Surge Capacity

In the event of a mass casualty event, healthcare organizations must be able to increase their services quickly in response to the crisis. This is an organization's surge capacity, "the ability to expand care capabilities in response to sudden or prolonged demand" (JCAHO, 2003). Staffing levels, education and training, decontamination capabilities, vaccination programs for direct caregivers, volunteer resources, and stockpiling of supplies must be assessed while, in most cases, routine care continues.

The ability of the organization to "degrade gracefully" must be considered. A healthcare organization should plan for a reduction in services as the number of patients climb. The goal is to engineer and manage failures and thus to avoid "catastrophic failure" (JCAHO, 2003). During a state of emergency, it may be impossible to follow normal practice guidelines. JCAHO recommends that hospitals and oversight agencies "provide for waiver of regulatory requirements under conditions of extreme emergency" (JCAHO, 2003).

Triage

Pre-decontamination triage serves three purposes:

• Distinguishes contaminated individuals from other patients arriving at the hospital by identifying symptoms and victim's proximity to a known chemical release
• Identifies patients who require immediate stabilization before they enter the decontamination system
• Identifies injuries or critical pre-hospital treatment materials that will require special handling inside the decontamination system (OSHA, 2005)

Post-decontamination triage for medical treatment should occur in the hospital post-decontamination zone, after victims are inspected and found to be free of contamination. Some hospitals combine decontamination and initial medical treatment (such as antidotes), which means either the healthcare worker attempts medical triage while wearing PPE (preferred) or the worker is at risk of exposure from victims who have not been adequately decontaminated (OSHA, 2005).

Decontamination Activities

Hospitals must identify spaces that will support decontamination activities (including equipment storage) and ensure that operations can continue in the event one area of the hospital becomes contaminated. Hospitals planning additions or remodeling projects have a unique opportunity to design spaces appropriately. Other hospitals should use creative planning to identify existing architectural features that they can use to their advantage. Nonambulatory victims can require a substantial proportion of first receivers' time and efforts. First receivers are likely to experience the greatest exposure while assisting these victims (OSHA, 2005).

Because victims often will not present to a hospital immediately following exposure to a biological agent, decontamination will not be necessary in most cases (TIH, 2004). If decontamination is necessary, numerous agencies and organizations recommend a shower time of approximately five minutes for contaminated victims brought to a hospital. Despite the fact that there is no empirical data, operational procedures deem this time to be adequate. Numerous agencies and programs recommend the use of water and a liquid soap with good surfactant properties (such as hand dishwashing detergent) to decontaminate victims during emergencies and mass casualties involving hazardous substances (OSHA, 2005).

Isolation and Lockdown

Hospitals can use a variety of methods to limit unauthorized access to the emergency department until the victims have been decontaminated. The methods range from a guard at the locked door with a key to sophisticated keycard systems controlled at a central command center. These more complex systems tend to be associated with urban or recently modernized hospitals and are intended for use in any type of disturbance. Hospitals can use these methods if situations suggest that an unruly crowd will force its way into the hospital (OSHA, 2005).

Security

Site security helps maintain order and control traffic around the decontamination facility and the hospital entrances. Security officers might need to control a contaminated individual to prevent other staff from becoming exposed and to protect equipment. Security officers also ensure contaminated victims do not bypass the decontamination hospital or enter the ED without passing inspection. In cases of civil disturbance, properly identified security officers protect the decontamination facility and staff so normal operations can continue (OSHA, 2005).

Personal Protective Equipment

Hospitals should select personal protective equipment (PPE) such as respirators, suits, gloves, and face and eye protection based on a hazard assessment that identifies the hazards to which employees might be exposed. Under OSHA's Personal Protective Equipment Standard, or the parallel State Plan standards, all employers, including hospitals, must certify in writing that the hazard assessment has been performed. For first-receiver PPE, hospitals may base the hazard assessment on OSHA's Best Practices document. Hospitals likely to respond to incidents involving a specific hazard should adjust the PPE accordingly (OSHA, 2005).

OSHA's Personal Protective Equipment Standard also requires that employees be provided with equipment that fits appropriately. Some hospitals assign a set of protective equipment to a specific individual, and that equipment is stored in a container marked with the individual's name. Other hospitals maintain general supplies of PPE, storing sets of equipment by size. In this case, the packages are clearly marked only with the size. Each first receiver tries on equipment in advance to determine what size group fits best so that, during an emergency, the employee can quickly locate an appropriate PPE set (OSHA, 2005).

Personal protective equipment selection for first receivers has been a topic of extensive discussion. At the root of this discussion is the need for hospitals to provide adequate protection for the reasonably anticipated worst-case scenario, despite having limited information regarding the nature of the substance with which victims may be contaminated. This lack of information challenges hospitals' abilities to conduct the hazard assessments on which PPE selection must be based (OSHA, 2005).

Infection Control

Heightened awareness by infection control (IC) professionals facilitates recognition of the release of a biological agent. Infection control professionals are involved with many aspects of hospital operations and several departments, and with counterparts in other hospitals. As a result, they may recognize changing patterns or clusters in a hospital or in a community that might otherwise go unrecognized (CDC, 2001).

Infection control professionals should set up a clinical syndrome–monitoring system for hospital departments most likely to be involved in a bioterrorism event. At a minimum, this should include monitoring:

• Emergency department diversions due to increased visits to the ED or to unavailability of beds in CCU
• Increases in the number of patients with influenza-like illness, rash with fever, gastroenteritis (vomiting and/or diarrhea), and acute asthma attacks
• Unexplained deaths occurring in otherwise healthy persons, especially if there is clinical evidence suggestive of an infectious disease process
• Increases in the number of persons with sepsis or septic shock (TIH, 2004).

Infection control professionals should ensure that hospitals have current telephone numbers for notification of both internal and external contacts and that they are distributed to the appropriate personnel. They should work with clinical microbiology laboratories, on- or off-site, that receive specimens for testing from their facility to ensure that cultures from suspicious cases are evaluated appropriately (CDC, 2001).

Wastewater Management

Wastewater from decontamination showers can contain low-level concentrations of the substance(s) with which victims are contaminated. Given the opportunity to plan for decontamination activities (by designing and installing or purchasing decontamination facilities, developing procedures, and preparing staff), hospitals should consider the management of decontamination shower water as part of their emergency preparedness plan (OSHA, 2005).

Decontaminating Surfaces and Equipment

The hospital emergency management plan should include procedures for cleaning equipment and surfaces during and after an incident. Cleaning should be performed by properly protected and trained employees. Items that cannot be decontaminated safely should be processed for appropriate disposal. It is unlikely that portable gear could be adequately decontaminated after an incident involving a persistent or highly toxic agent (OSHA, 2005).

REPORTING AN INCIDENT OF BIOTERRORISM

In the event that an incident of bioterrorism occurs in your community, you should know what to report and to whom the report should be sent. First reporters should start at the healthcare organization or hospital level by reporting to the department supervisor, laboratory, and infection control department. Then contact the local health/regional departments, which will contact the Nevada State Health Division and the CDC. In 2003 the CDC published recommended practices for early detection and reporting of a terrorist event. Successful reporting of a bioterrorism event results from good planning, education, and awareness, as well as regular standardized testing before an occurrence.

Telephone should be the primary means for immediate reporting because it is the most direct, rapid, and easy-to-use method. A trained public health professional should be able to handle up to 80% of incoming queries. Standards should be established to ensure a reliable and immediate response to notifiable diseases and health conditions. The time from initial receipt of the call to a response by the health department on-call physician should not exceed 30 minutes. If the telephone system fails, health departments must have an alternative for receiving urgent reports (CDC, 2003c).

Nevada Reporting
NV State Health Division
Main: 775-684-4200
After hours: 775-688-2830
Infectious disease reporting: 775-684-5911

The Health Alert Network (HAN) is a nationwide communications system established by the CDC and implemented by each state under guidelines from the Public Health Information Network (PHIN). The Nevada HAN provides a 24/7 means of two-way communication for all critical health information among the Nevada State Health Division and local and rural healthcare professionals. These professionals include physicians, nurses, hospitals, laboratories, clinicians, public health workers, emergency management, and public officials (NSHD, 2007).

The Health Alert Network helps to address issues created by our increasingly mobile society and pressures on local and state health infrastructures to be prepared to deal with public health emergencies, including bioterrorism. Rapid and efficient communication systems help to ensure that critical events do not go undiagnosed or unreported while spreading to other localities (NSHD, 2007).

Local healthcare providers my find themselves on the frontline—in a position to notice unusual case patterns or a sudden increase in similar cases in the emergency room. Their facilities need to be able to respond quickly in such situations and the HAN is intended to help by providing the following:

• Ongoing surveillance activities to quickly identify potential health threats
• Laboratory capability to perform testing to determine the threat agent
• The ability to conduct disease investigations
• Effective protocol for reporting incidents and sharing information
• Efficient emergency communications among all involved parties (NSHD, 2007)

Eligible Public Health Partners in Nevada HAN

HAN follows a role-based system for enrolling partners who occupy both required and optional public health roles. Roles are assigned at state, county, and hospital levels and states may add additional roles as necessary. Grouping by roles facilitates efficient communication of notices to relevant groups. In addition to the 35 roles identified by the CDC, Nevada HAN includes tribal communities, military installations located in the counties, and healthcare providers (physicians, physician assistants, nurse practitioners) (NSHD, 2007a; NVSBN, 2007).

HAN members are identified and tracked in a secure database maintained by Public Health Preparedness. Subscription is free but does require an email address. Enrollees receive a user name and password and establish a personal profile to facilitate receipt of alerts. When an alert is received, the subscriber logs on to a secure website to retrieve the message and obtain links to any additional information (NVSBN, 2007).

Interested healthcare professionals should go to the Nevada Health Alert Network website listed in Nevada Resources (end of this course) for further information and links to the signup and login processes (NSHD, 2007).

Alert Message Types

CDC HAN messages range from informational updates of general interest to alerts that require immediate action (NSHD, 2007). For health emergencies that are unique to the state, a state or county officer may also send out alerts (NVSBN, 2007).

Alert types include:

Health Alert: Conveys the highest level of importance; warrants immediate action or attention.

Health Advisory: Provides important information for a specific incident or situation; may not require immediate action.

Health Update: Provides updated information regarding an incident or situation; unlikely to require immediate action.

Health Alert Network Information Service Message: General correspondence from CDC, which is not considered to be of an emergency nature.

Posted February 29, 2008

Expires February 1, 2010

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