NV: Bioterrorism and Weapons of Mass DestructionPage 6 of 9

4. Biological Weapons

From a scientific and medical perspective, bioterrorism—using biological weapons to produce disease in humans—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

As with chemical agents, 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 individuals may be the first sign of a release, and those infected 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 should be alert to illness patterns and diagnostic clues that indicate an unusual infectious disease outbreak that could be associated with intentional release of a biological agent. In addition, they should watch 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, 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). The CDC’s Emergency Preparedness and Response website has links to and information on the various tools available, as well as other resources.

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. Technology changes and the plethora of programs and data have also affected these efforts (CDC, 2004b, 2012; Dembek et al., 2004). (See also the CDC resource website at: http://emergency.cdc.gov/bioterrorism/surveillance.asp.)

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).

Epidemiologic Clues That May Signal a Covert Bioterrorism Attack

  • Large number of ill persons with similar disease or syndrome
  • Large number of unexplained disease, syndrome or deaths
  • Unusual illness in a population
  • Higher morbidity and mortality than expected with a common disease or syndrome
  • Failure of a common disease to respond to usual therapy
  • Single case of disease caused by an uncommon agent
  • Multiple unusual or unexplained disease entities coexisting in the same patient without other explanation
  • Disease with an unusual geographic or seasonal distribution
  • Multiple atypical presentations of disease agents
  • Similar genetic type among agents isolated from temporally or spatially distinct sources
  • Unusual, atypical, genetically engineered, or antiquated strain of agent
  • Endemic disease with unexplained increase in incidence
  • Simultaneous clusters of similar illness in non-contiguous areas, domestic or foreign
  • Atypical aerosol, food, or water transmission
  • Ill people presenting near the same time
  • Deaths or illness among animals that precedes or accompanies illness or death in humans
  • No illness

Source: CDC, 2001.

As noted earlier, a variety of factors affect the potential public health impact of an intentionally released biological agent:

  • Lethality—how effectively it kills
  • Infectivity—how easily it spreads
  • Virulence—how likely it is to cause disease
  • How easily it is dispersed
  • Availability of medical treatment and/or vaccine
  • Dosage needed to cause disease
  • Stability of the compound (NTI, 2015a,e)

It may be difficult to pinpoint the time and location of a biological agent’s release because of the variation in incubation period among organisms. Some diseases show a rapid onset of symptoms and early treatment is critical. For example, plague has a rapid onset and is potentially fatal within 12 to 24 hours if untreated; botulism toxin also has a rapid onset and requires immediate supportive treatment. On the other hand, smallpox can be treated effectively by vaccination within 2 to 3 days of symptom onset. But smallpox, like plague, is highly contagious and has the potential to cause widespread panic, and in the case of smallpox, which is believed to have been eradicated, not enough vaccine exists should a widespread outbreak occur. Conversely, plague and anthrax, despite their potential for causing serious illness and death, are effectively treated with antibiotics.

Categories of Diseases and Biological Agents

Bioterrorism agents can be separated into three categories, depending on how easily they can be spread and the severity of illness or death they cause. Category A agents are considered the highest risk and Category C agents are those that are considered emerging threats for disease (CDC, 2017a).

Category A Diseases or Agents

Category A diseases or agents are high priority and include organisms that pose the highest risk to the public and national security because they:

  • Are easily spread or transmitted from person to person
  • Result in high mortality rates and have the potential for major public health impact
  • May cause public panic and social disruption
  • Require special action for public health preparedness (CDC, 2017a)

Category A bioterrorism agents are:

  • Anthrax (Bacillus anthracis)
  • Botulism (Clostridium botulinum toxin)
  • Plague (Yersinia pestis)
  • Smallpox (variola major)
  • Tularemia (Francisella tularensis)
  • Viral hemorrhagic fevers, including
    • Filoviruses (Ebola, Marburg)
    • Arenaviruses (Lassa, Machupo) (CDC, 2017a)

Category B Diseases or Agents

Category B diseases or agents are the second highest priority because they:

  • Are moderately easy to disseminate
  • Result in moderate illness rates and low mortality rates, and
  • Require specific enhancements of CDC’s diagnostic capacity and enhanced disease surveillance (CDC, 2017a)

Category B diseases or agents include:

  • Brucellosis (Brucella species)
  • Epsilon toxin of Clostridium perfringens
  • Food safety threats (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—Venezuelan equine encephalitis, eastern and western equine encephalitis)
  • Water safety threats (Vibrio cholerae, Cryptosporidium parvum) (CDC, 2017a)

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 they:

  • Are easily available
  • Are easily produced and spread
  • Have potential for high morbidity and mortality rates and major health impact

Agents include emerging infectious diseases such as Nipah virus and hantavirus (CDC, 2017a).

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, category B. Other important category B agents include any organism that threatens the water or food supply.


Anthrax has been recognized as an infectious disease of animals and humans for millennia. Within the United States, animal anthrax is reported in most years, but naturally occurring human anthrax is rare. Worldwide, however, the disease is common in wild and domestic animals and not uncommon among people who interact with animals in agricultural regions of South and Central America, sub-Saharan Africa, central and southwestern Asia, and southern and eastern Europe (Hendricks, et al. [CDC], 2014).

Bacillus anthracis, the causative agent of anthrax, is a nonmotile spore-forming, gram-positive, rod-shaped bacterium. Biodefense experts often place B. anthracis at or near the top of the list for potential threat agents. Inhalation anthrax is particularly deadly, as demonstrated by the 1979 accidental release of B. anthracis from a military microbiology facility in the Sverdlovsk region of Russia; 88% (66/75) of patients reported with inhalation anthrax died. More recently, humans have acquired disease from exposure to spores released purposefully as a bioterrorist weapon and accidentally from naturally occurring sources (Hendricks, et al. [CDC], 2014).

If a bioterrorist attack were to happen, Bacillus anthracis would be one of the biological agents most likely to be used. Biological agents are germs that can sicken or kill people, livestock, or crops. Anthrax is one of the most likely agents to be used because:

  • Anthrax spores are easily found in nature, can be produced in a lab, and can last for a long time in the environment.
  • Anthrax makes a good weapon because it can be released quietly and without anyone knowing. The microscopic spores could be put into powders, sprays, food, and water. Because they are so small, you may not be able to see, smell, or taste them.
  • Anthrax has been used as a weapon before. (CDC, 2014)

Anthrax has been used as a weapon around the world for nearly a century. In 2001 powdered anthrax spores were deliberately put into letters that were mailed through the U.S. postal system. Twenty-two people, including 12 mail handlers, got anthrax, and five of these 22 people died.

A letter sent in 2001 to Senate Majority Leader Tom Daschle contained anthrax powder.

A letter sent in 2001 to Senate Majority Leader Tom Daschle contained anthrax powder. Beginning one week after the September 11 attacks, letters containing anthrax spores were mailed to several news media offices and two U.S. Senators, killing five people and infecting 17 others. Source: Wikimedia Commons.

A subset of select agents and toxins have been designated as Tier 1 because these biological agents and toxins present the greatest risk of deliberate misuse with significant potential for mass casualties or devastating effect to the economy, critical infrastructure, or public confidence, and pose a severe threat to public health and safety. Bacillus anthracis is a Tier 1 agent.

An anthrax attack could take many forms. For example, it could be placed in letters and mailed, as was done in 2001, or it could be put into food or water. Anthrax also could be released into the air from a truck, building, or plane. This type of attack would mean the anthrax spores could easily be blown around by the wind or carried on people’s clothes, shoes, and other objects. It only takes a small amount of anthrax to infect a large number of people.

If anthrax spores were released into the air, people could breathe them in and get sick with anthrax. Inhalation anthrax is the most serious form and can kill quickly if not treated immediately. If the attack were not detected by one of the monitoring systems in place in the United States, it might go unnoticed until doctors begin to see unusual patterns of illness among sick people showing up at emergency rooms (CDC, 2014).

There are four clinical forms of anthrax: cutaneous or skin, inhalation or respiratory tract, gastrointestinal, and injection (has occurred in northern Europe but has never been reported in the United States) (CDC, 2017b).

Cutaneous Anthrax

When anthrax spores get into the skin, usually through a cut or scrape, a person can develop cutaneous anthrax. This can happen when a person handles infected animals or contaminated animal products like wool, hides, or hair. Cutaneous anthrax is most common on the head, neck, forearms, and hands. It affects the skin and tissue around the site of infection.

Cutaneous anthrax is the most common form of anthrax infection, and it is also considered to be the least dangerous. Infection usually develops from 1 to 7 days after exposure. Without treatment, up to 20% of people with cutaneous anthrax may die. However, with proper treatment, almost all patients with cutaneous anthrax survive (CDC, 2014a).

Cutaneous anthrax symptoms can include:

  • A group of small blisters or bumps that may itch
  • Swelling can occur around the sore
  • A painless skin sore (ulcer) with a black center that appears after the small blisters or bumps, most often on the face, neck, arms, or hands (CDC, 2014e)
Inhalation Anthrax

When a person breathes in anthrax spores, they can develop inhalation anthrax. People who work in places such as wool mills, slaughterhouses, and tanneries may breathe in the spores when working with infected animals or contaminated animal products from infected animals. Inhalation anthrax starts primarily in the lymph nodes in the chest before spreading throughout the rest of the body, ultimately causing severe breathing problems and shock.

Inhalation anthrax is considered to be the deadliest form of anthrax. Infection usually develops within a week after exposure, but it can take up to 2 months. Without treatment, only about 10% to 15% of patients with inhalation anthrax survive. However, with aggressive treatment, about 55% of patients survive (CDC, 2014b).

Inhalation anthrax symptoms can include:

  • Fever and chills
  • Chest discomfort
  • Shortness of breath
  • Confusion or dizziness
  • Cough
  • Nausea, vomiting, or stomach pains
  • Headache
  • Sweats (often drenching)
  • Extreme tiredness
  • Body aches (CDC, 2014e)
Gastrointestinal Anthrax

When a person eats raw or undercooked meat from an animal infected with anthrax, they can develop gastrointestinal anthrax. Once ingested, anthrax spores can affect the upper gastrointestinal tract (throat and esophagus), stomach, and intestines.

Gastrointestinal anthrax has rarely been reported in the United States. Infection usually develops from 1 to 7 days after exposure. Without treatment, more than half of patients with gastrointestinal anthrax die. However, with proper treatment, 60% of patients survive (CDC, 2014c).

Gastrointestinal anthrax symptoms can include:

  • Fever and chills
  • Swelling of neck or neck glands
  • Sore throat
  • Painful swallowing
  • Hoarseness
  • Nausea and vomiting, especially bloody vomiting
  • Diarrhea or bloody diarrhea
  • Headache
  • Flushing (red face) and red eyes
  • Stomach pain
  • Fainting
  • Swelling of abdomen (stomach) (CDC, 2014e)
Injection Anthrax

Recently, another type of anthrax infection has been identified in heroin-injecting drug users in northern Europe. This type of infection has never been reported in the United States.

Symptoms may be similar to those of cutaneous anthrax, but there may be infection deep under the skin or in the muscle where the drug was injected. Injection anthrax can spread throughout the body faster and be harder to recognize and treat. Lots of other more common bacteria can cause skin and injection site infections, so a skin or injection site infection in a drug user does not necessarily mean the person has anthrax (CDC, 2014d).

Injection anthrax symptoms can include:

  • Fever and chills
  • A group of small blisters or bumps that may itch, appearing where the drug was injected
  • A painless skin sore with a black center that appears after the blisters or bumps
  • Swelling around the sore
  • Abscesses deep under the skin or in the muscle where the drug was injected (CDC, 2014e)


Botulism is a neuroparalytic illness characterized by symmetric, descending flaccid paralysis of motor and autonomic nerves, always beginning with the cranial nerves.

Signs and symptoms in an adult may include:

  • Diplopia (double vision)
  • Blurred vision
  • Ptosis (drooping eyelids)
  • Slurred speech
  • Dysphagia (difficulty swallowing)
  • Dry mouth
  • Muscle weakness

Signs and symptoms in foodborne illness may also include:

  • Abdominal pain
  • Nausea
  • Vomiting
  • Diarrhea

Signs and symptoms in an infant may include:

  • Poor feeding
  • Diminished suckling and crying ability
  • Neck and peripheral weakness (“floppy baby”)
  • Constipation
  • Respiratory failure

If untreated, illness might progress to cause descending paralysis of respiratory muscles, arms, and legs (CDC, 2017c).

Botulism Case Consultation

If you suspect your patient may have botulism, call your state public health department immediately. If there is no answer, contact CDC 24/7 at 770 488 7100.

  • For non-infant cases: State public health officials can reach the CDC clinical emergency botulism service for consultation and antitoxin 24/7 at 770 488 7100. If administered early in the course of illness, antitoxin can prevent progression of illness and shorten its duration.
  • For infant botulism: The Infant Botulism Treatment and Prevention Program at the California Department of Public Health provides consultation 24/7 and can be reached at 510 231 7600.

If clinical consultation with state public health departments and CDC supports botulism, request antitoxin immediately and begin treatment as soon as it is available. Do not wait for laboratory confirmation.

Source: CDC, 2017c.

Etiology and Transmission

Botulism is caused by a potent neurotoxin produced from Clostridium botulinum, and rare strains of C. butyricum and C. baratii, which are anaerobic, spore-forming bacteria.

Transmission differs by type of botulism:

Foodborne botulism occurs when a person ingests botulinum toxin, which leads to illness within a few hours to days. Outbreaks of foodborne botulism have potential to be a public health emergency because the contaminated food may be eaten by other people. A frequent source is home-canned foods prepared in an unsafe manner.

Infant botulism occurs each year in a small number of susceptible infants who harbor C. botulinum in their intestinal tract. It occurs when an infant ingests spores of C. botulinum, which in turn colonize the intestinal tract and produce toxin.

Wound botulism is a rare disease that occurs when wounds infected with C. botulinum secrete the toxin. It occurs more frequently among persons who inject drugs, but has also been seen in cases of traumatic injury, such as motorcycle crashes, and surgeries.

Adult intestinal colonization (also called adult intestinal toxemia) is an even rarer type of botulism. It involves intestinal colonization in a person older than one year of age. In the small number of these cases, most patients had a history of gastrointestinal surgery or illness, such as inflammatory bowel disease, which might have predisposed them to enteric colonization. No other specific risk factors have been identified.

Iatrogenic botulism occurs after an overdose of injected botulinum toxin for cosmetic or medical purposes (CDC, 2017c).

Diagnosis and Testing

Botulism differs from other flaccid paralyses in that it always manifests initially with prominent cranial nerve palsies. It also differs in its invariable descending progression, in its symmetry, and in its absence of sensory nerve dysfunction.

Botulism is frequently misdiagnosed, most often as a polyradiculoneuropathy (Guillain-Barré or Miller-Fisher syndrome), myasthenia gravis, or other diseases of the central nervous system.

Clinical diagnosis of botulism is confirmed by specialized laboratory testing that often requires days to complete. Routine laboratory test results are usually unremarkable (CDC, 2017c).

Initial diagnosis is based on clinical symptoms. Do not wait for laboratory confirmation to begin treatment.

Laboratory confirmation is done by demonstrating the presence of botulinum toxin in serum, stool, or food, or by culturing C. botulinum, C. butyricum, or C. baratii from stool, a wound, or food.

Other tests and laboratory studies to help with clinical diagnosis include:

  • Routine lab tests (CBC, electrolytes, LFTs, urinalysis): generally not helpful in diagnosis as these tests show no characteristic abnormalities
  • Cerebrospinal fluid (CSF) studies: essentially normal, although occasionally a borderline elevation in protein level may be seen
  • Tensilon test: A normal test helps to differentiate botulism from myasthenia gravis; borderline positive tests can occur in botulism.
  • CTs and MRIs: Normal CTs and MRIs help to rule out cerebrovascular accident (CVA). (CDC, 2017c)

Administer botulinum antitoxin or BabyBIG as soon as possible. Antitoxin does not reverse paralysis but arrests its progression. Recovery follows the regeneration of new neuromuscular connections.

Exercise meticulous intensive care, including monitoring of respiratory function and, when required, mechanical ventilation. In more severe cases, ventilator support may be required for weeks to months.

Treatment for wound botulism may also include wound debridement to remove the source of toxin‑producing bacteria and antibiotic therapy (CDC, 2017c).

Infection Control

Medical personnel caring for patients with suspected botulism should use standard precautions. Botulism is not transmitted person-to-person.

Patients with botulism do not need to be isolated (CDC, 2017c).


Death can result from respiratory failure or the consequences of extended paralysis. About 5% of patients die. Recovery takes weeks to months. Those who survive may have fatigue and shortness of breath for years (CDC, 2017c).


In 2015 there were 199 cases of laboratory-confirmed botulism reported to the CDC. Of these, 39 were foodborne, 141 were infant botulism, 15 were cases of wound botulism, and 4 cases were of unknown etiology (CDC, 2017c).

Plague (Yersinia pestis)

Plague is a disease caused by Yersinia pestis (Y. pestis), a bacterium found in rodents and their fleas in many areas around the world (CDC, 2015d).


Bubonic plague is the most common primary manifestation, with a bubo usually occurring in the groin, axilla, or cervical nodes. Buboes are often so painful that patients are generally guarded and have restricted movement in the affected region. The incubation period for bubonic plague is usually 2 to 6 days.

If bubonic plague is untreated, plague bacteria invade the bloodstream and spread rapidly, causing septicemic plague, and if the lungs are seeded, secondary pneumonic plague. Septicemic and pneumonic plague may also be primary manifestations. A person with pneumonic plague may experience high fever, chills, cough, and breathing difficulty and may expel bloody sputum. If pneumonic plague patients are not given specific antibiotic therapy, the disease can progress rapidly to death.

Although the majority of patients with plague present with a bubo, some may have nonspecific symptoms. For example, septicemic plague can present with prominent gastrointestinal symptoms such as nausea, vomiting, diarrhea, and abdominal pain. Additional rare forms of plague include pharyngeal, meningeal, and cutaneous.

Appropriate diagnostic samples include blood cultures, lymph node aspirates if possible, and/or sputum, if indicated. Drug therapy should begin as soon as possible after the laboratory specimens are taken. If plague is suspected, local and state health departments should be notified immediately. If patients have pneumonic signs, they should also be isolated and placed on droplet precautions (CDC, 2015a).

Symptoms and Transmission

Pneumonic plague can be transmitted from person to person; bubonic plague cannot. Pneumonic plague affects the lungs and is transmitted when a person breathes in Y. pestis particles. Bubonic plague is transmitted through the bite of an infected flea or exposure to infected material through a break in the skin (CDC, 2015d).

Plague symptoms depend on how the patient was exposed to the plague bacteria.

Bubonic: Sudden onset of fever, headache, chills, and weakness and one or more swollen, tender, and painful lymph nodes (called buboes). This usually results from the bite of an infected flea.

Septicemic: Fever, chills, extreme weakness, abdominal pain, shock, and possibly bleeding into the skin and other organs. This usually results from bites of infected fleas or from handling an infected animal.

Pneumonic: Fever, headache, weakness, and a rapidly developing pneumonia with shortness of breath, chest pain, cough, and sometimes bloody or watery mucous. Nausea, vomiting, and abdominal pain may also occur. May develop from inhaling infectious droplets or from untreated bubonic or septicemic plague that spreads to the lungs (CDC, 2015a,b,c,d).

Pneumonic Plague as Bioweapon

Yersinia pestis used in an aerosol attack could cause cases of the pneumonic form of plague. One to six days after becoming infected with the bacteria, people would develop pneumonic plague. Once people have the disease, the bacteria can spread to others who have close contact with them. Because of the delay between being exposed to the bacteria and becoming sick, people could travel over a large area before becoming contagious and possibly infecting others. Controlling the disease would then be more difficult. A bioweapon carrying Y. pestis is possible because the bacterium occurs in nature and could be isolated and grown in quantity in a laboratory. Even so, manufacturing an effective weapon using Y. pestis would require advanced knowledge and technology (CDC, 2015d).

National and state public health officials have large supplies of drugs needed in the event of a bioterrorism attack. These supplies can be sent anywhere in the United States within 12 hours (CDC, 2015d).

Smallpox (Variola)

Thousands of years ago, variola virus (smallpox virus) emerged and began causing illness and deaths in human populations, with smallpox outbreaks occurring from time to time. Thanks to the success of vaccination, the last natural outbreak of smallpox in the United States occurred in 1949. In 1980 the World Health Assembly declared smallpox eradicated (eliminated), and no cases of naturally occurring smallpox have happened since.

Smallpox research in the United States continues and focuses on the development of vaccines, drugs, and diagnostic tests to protect people against smallpox in the event that it is used as an agent of bioterrorism (CDC, 2016c).

Before smallpox was eradicated, it was a serious infectious disease caused by the variola virus. It was contagious—meaning, it spread from one person to another. People who had smallpox had a fever and a distinctive, progressive skin rash.

Most people with smallpox recovered, but about 3 out of every 10 people with the disease died. Many smallpox survivors have permanent scars over large areas of their body, especially their faces. Some are left blind (CDC, 2016c).

Before smallpox was eradicated, it was mainly spread by direct and fairly prolonged face-to-face contact between people. Smallpox patients became contagious once the first sores appeared in their mouth and throat (early rash stage). They spread the virus when they coughed or sneezed and droplets from their nose or mouth spread to other people. They remained contagious until their last smallpox scab fell off.

These scabs and the fluid found in the patient’s sores also contained the variola virus. The virus can spread through these materials or through the objects contaminated by them, such as bedding or clothing. People who cared for smallpox patients and washed their bedding or clothing had to wear gloves and take care to not get infected.

Rarely, smallpox has spread through the air in enclosed settings, such as a building (airborne route).

Smallpox can be spread by humans only. Scientists have no evidence that smallpox can be spread by insects or animals (CDC, 2016c).

A person with smallpox goes through several stages as the disease progresses. Each stage has its own signs and symptoms.

  • Incubation
  • Initial symptoms
  • Early rash
  • Pustular rash and scabs
  • Scabs fall off
  • No scabs (CDC, 2016c)

There is no proven treatment for smallpox disease, but some antiviral drugs may help treat it or prevent it from getting worse. There also is a vaccine to protect people from smallpox. If there were a smallpox outbreak, health officials would use the smallpox vaccine to control it (CDC, 2016c).

Distribution of Pox Rash

An illustration showing the different rash pattern between smallpox and chickenpox.

Most likely, if smallpox is released into the United States as a bioterrorist attack, public health authorities will learn of it when the first afflicted person goes to a hospital for treatment of an unknown illness. Physicians will examine the person using tools developed by CDC to decide if signs and symptoms are similar to those of smallpox. If they suspect the person has smallpox, they will isolate and care for the person in the hospital so that others do not come in contact with the smallpox virus. The hospital will contact local public health authorities that they have a patient who might have smallpox.

Local public health authorities would then alert public health officials at the state and federal level to help diagnose the disease. If experts confirm the illness is smallpox, then CDC, along with state and local public health authorities, will put into place their plans to respond to a bioterrorist attack with smallpox (CDC, 2016c).

Best Practices for First Receivers

Healthcare workers risk occupational exposures to biological 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 at a facility and the corresponding hazards the 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; Kelen, 2008). 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.

Individual personnel on an emergency response team have slightly differing concerns and responsibilities when it comes to surge situations. While surge capacity planning is an administrative level concern, individual healthcare providers should understand the basic concept and the need for guidelines in order to participate effectively in training and any necessary implementation. The CDC’s handbook, Updated in a Moment’s Notice: Surge Capacity in Terrorist Bombings, is available here: http://stacks.cdc.gov/view/cdc/5713/ (CDC, 2010).

The ability of the organization to “degrade gracefully” must also be considered. A healthcare organization should have a plan to deal with a reduction in services as the number of patients increases. 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. The Joint Commission recommends that hospitals and oversight agencies “provide for waiver of regulatory requirements under conditions of extreme emergency” (JCAHO, 2003).


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 that 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, and first receivers are likely to experience the greatest exposure while assisting these victims (OSHA, 2005).

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 for 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 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).


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 their 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 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 employees who are properly protected and trained. 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 of an incident of bioterrorism 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. Successful reporting of a bioterrorism event results from good planning, education, and awareness, as well as regular standardized testing before an occurrence.

In most cases telephone will still be the primary means for immediate reporting because it is direct, rapid, and easy-to-use. There should always be a backup communication plan (eg, cell phones or other means) in case of a telephone system failure. In every institution standards should be established to ensure a reliable and immediate response to notifiable diseases and health conditions.

Nevada Reporting
Nevada Division of Public and Behavioral Health (DPBH)

Main: 775 684 4200

Public Health Emergency: 775 684 5920

Infectious disease reporting: 775 684 5911

   Washoe County: 775 328 2447 (24 hr)

   Southern Nevada: 702 759 1300, option #2 (24 hr)

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