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BIOLOGICAL AGENTS

Letters containing anthrax spores caused deaths and illnesses in the fall of 2001. The situation demonstrated in a frightening way that the intentional use of biological agents to cause disease is a very real threat. Anthrax is not the only infectious agent that could be used as a weapon. There is also concern about the potential for outbreaks of smallpox, plague, botulism, and other diseases.

Anthrax

Human anthrax is a serious disease that has three major forms: lungs (inhalation), skin (cutaneous), and the digestive track (gastrointestinal). While inhalation anthrax is the most deadly form, all types of anthrax can lead to blood poisoning (septicemia) and death. Anthrax is not contagious. The illness cannot be spread from person to person.

Anthrax is caused by a bacterium called Bacillus anthracis. The bacterium forms a spore, or protective shell, that allows the germ to survive for many years in soil and other conditions.

Health Effects The symptoms of anthrax usually appear within 7 days after becoming infected (incubation period). Symptoms vary depending on how the disease was contracted.

Inhalational Anthrax:
Inhalation is the most lethal form of anthrax. Initial symptoms of inhalation anthrax infection may resemble a common cold or flu, including sore throat, mild fever, muscle aches and malaise. After several days, the symptoms may progress to severe breathing problems and shock. Inhalation anthrax is often fatal. Early antibiotic treatment of anthrax is essential — delay lessens the chances for survival.
Inhalation anthrax is caused by breathing anthrax spores. The spores must be able to float in the air (aerosolized) in order to be inhaled. The number of spores that cause human infection is unknown. The number of days from the time of infection to the development of the disease in people is also unclear. The incubation period has been reported to range from 1 to 7 days, but is believed to be capable of causing disease for up to 60, and possibly as long as 100 days.
Cutaneous Anthrax:
Skin contact with contaminated mail or other objects can cause skin anthrax. Cutaneous anthrax is the most common naturally occurring form of anthrax. It usually affects people that have had skin contact with contaminated meat, wool, hides, or leather from infected animals. The incubation period ranges from 1-12 days. Cutaneous anthrax is the least serious form of anthrax.
The first symptom is a small, painless sore that develops into a blister. One or two days later, the blister develops a black scab in the center. Lymph glands near the infected area may swell. Deaths from cutaneous anthrax are rare if patients are given prompt and appropriate treatment with antibiotics.
Gastrointestinal Anthrax:

This form of anthrax usually results from eating raw or undercooked contaminated meat. It has an incubation period of 1-7 days. The initial signs include nausea, loss of appetite, vomiting, and fever, followed by abdominal pain, vomiting of blood, and severe diarrhea.

Diagnosis treatment, and vaccine

Diagnosis

Anthrax is diagnosed by finding anthrax bacteria in samples taken from blood, skin blisters, or respiratory secretions, or by measuring antibodies in the blood. Diagnosis for inhalational anthrax may also include a chest X-ray or fluid from the spine (if there are signs meningitis). A nasal swab is NOT a test to diagnose anthrax. The nasal swab is a tool that can be used along with other environmental sampling methods to determine how widely spores have spread.

Treatment

A person that has come in contact with anthrax, but without a positive test to diagnose the disease, is considered potentially exposed. Taking antibiotics after exposure (postexposure prophylaxis) can prevent individuals from developing the disease. In late 2001, postal workers, staff who worked in an U.S. Senate office building, mailroom workers, and others were given antibiotics after anthrax spores were found in their workplaces. Anthrax disease is treated with medications including penicillin, doxycycline, and fluoroquinolones, a group of antibiotics that includes ciprofloxacin. Medications to prevent and treat anthrax can cause side effects.

Awareness of anthrax symptoms can lead to faster diagnosis and treatment. Anyone who suspects that they have been exposed to anthrax or thinks they have signs of anthrax should immediately contact a medical provider.

Vaccine

There is a vaccine to prevent anthrax infection. However, vaccination against anthrax has not been recommended for the general public to prevent disease and is not available. It is not known whether the vaccine will prevent disease after there has been exposure.

Workplace Issues

To date, mail has been the only method that has been used to intentionally spread anthrax. However, it is important to keep in mind that anthrax spores could be introduced into a workplace through other means.

Anthrax and the Mail

The tragic and confusing events related to mail containing anthrax in the fall of 2001 resulted in new information as well as concerns regarding the spread of the disease. People became exposed when envelopes containing anthrax spores were opened. Later it was discovered that tiny invisible spores could be released through sealed envelopes and contaminate other mail under certain conditions.

Many government agencies and other employers have changed the way they receive and handle mail to try to prevent further exposure. For example, mail sent to elected and other government officials in Washington, D.C. is sanitized by irradiation before it is delivered.

The CDC has issued recommendations for recognizing and handling of suspicious mail/packages guidelines.

Some characteristics of suspicious packages and envelopes include the following:

  • Inappropriate or unusual labeling 

  • Excessive postage 

  • Handwritten or poorly typed addresses 

  • Misspellings of common words 

  • Strange return address or no return address 

  • Incorrect titles or title without a name 

  • Not addressed to a specific person 

  • Marked with restrictions, such as "Personal," "Confidential," or "Do not x-ray" 

  • Marked with any threatening language 

  • Postmarked from a city or state that does not match the return address

Appearance:

  • Powdery substance felt through or appearing on the package or envelope 

  • Oily stains, discolorations, or odor 

  • Lopsided or uneven envelope 

  • Excessive packaging material such as masking tape, string, etc. 

  • Excessive weight 

  • Ticking sound 

  • Protruding wires or aluminum foil


Handling of suspicious packages or envelopes*

  • If a package or envelope appears suspicious, DO NOT OPEN IT. 

  • Do not shake or empty the contents of any suspicious package or envelope. 

  • Do not carry the package or envelope, show it to others or allow others to examine it. 

  • Put the package or envelope down on a stable surface; do not sniff, touch, taste, or look closely at it or at any contents which may have spilled. 

  • Alert others in the area about the suspicious package or envelope. Leave the area, close any doors, and take actions to prevent others from entering the area. If possible, shut off the ventilation system. 

  • WASH hands with soap and water to prevent spreading potentially infectious material to face or skin. 

  • Seek additional instructions for exposed or potentially exposed persons. 

  • Notify a supervisor, a security officer, or law enforcement official. 

  • If possible, create a list of persons who were in the room or area when this suspicious letter or package was recognized and a list of persons who also may have handled this package or letter. Give this list to both the local public health authorities and law enforcement officials


*These recommendations were published on October 26, 2001, in "Update: Investigation of bioterrorism-related anthrax and interim guidelines for exposure management and antimicrobial therapy." (MMWR 2001;50:909-919) This document can be found here. 

Testing for anthrax contamination in the workplace

Environmental sampling can help determine if there is contamination, and after cleanup to allow re-entry into an area. The samples can be collected from the air, wiping smooth surfaces (non-porous), ventilation filters and ducts, and vacuuming large surfaces and porous areas such as carpets. Only high-efficiency particulate air (HEPA) vacuum cleaners can be used because regular home or industrial vacuum cleaners will spread spores. Before sampling is begun, the building's engineer should be consulted to determine airflow patterns and the design of the heating, ventilating, and air-conditioning system (HVAC). Since most building ventilation systems re-circulate air to other locations in the building, the ventilation system serving the contaminated area should be shut off to prevent further spread of any spores.

It is important to keep in mind that this is a new and developing area. Currently, there are no standards for exposure to anthrax spores. Decisions about whether it is useful to test, and where and how to sample must be made carefully. Caution must be used when drawing conclusions from test results.

For more information on environmental sampling visit American Postal Workers Union's website.

Investigation, cleanup and worker safety

Investigation and clean up of contaminated sites is specialized work that must be performed by highly trained personnel who use protective work practices and equipment. Respirators are needed to prevent breathing anthrax spores and protective clothing must be worn to prevent skin contact. Procedures and equipment are also necessary to decontaminate personnel as they leave the area that is contaminated with or is suspected of containing anthrax spores.

The Occupational Safety and Health Administration's (OSHA) Hazardous Waste Operations and Emergency Response Standard, also known as HAZWOPER, (29 CFR 1910.120) applies to these operations. The HAZWOPER standard protects workers who respond to uncontrolled or emergency releases of hazardous substances and clean up of sites contaminated with these substances. Under the standard, the definition of hazardous substances includes both chemicals and biological agents such as anthrax. The HAZWOPER standard includes requirements for emergency planning, training, equipment, protective clothing, work practices and other measures to prevent worker exposure.

CDC's recommendations for protecting investigators performing sampling.

OSHA's requirements and guidance regarding responding to anthrax incidents.

OSHA's HAZWOPER standard

Additional information about anthrax can be found at the following websites:

 

Smallpox

NOTE: See also Smallpox Update (12/6/2002).

Smallpox is a deadly contagious disease caused by variola virus. The elimination of smallpox infection from the world in the 1970s was a major public health success.

Health effects

The incubation period is about 12 days (range: 7 to 17 days) following exposure. Initial symptoms include high fever, fatigue, and head and backaches. A characteristic rash, most prominent on the face, arms, and legs, follows in 2-3 days. The rash starts with flat red lesions. The lesions become pus-filled and begin to crust early in the second week. Scabs develop and then separate and fall off after about 3-4 weeks. The majority of patients with smallpox recover, but death occurs in up to 30% of cases.

Smallpox is normally spread from one person to another by infected saliva droplets through close face-to-face contact (within about 6 feet). Persons with smallpox are most infectious during the first week of illness, because that is when the largest amount of virus is present in saliva. However, some risk of transmission lasts until all scabs have fallen off.

Treatment and vaccine

Treatment

There is no proven treatment for smallpox. Research is being done to evaluate the effectiveness of new antiviral agents. Patients with smallpox can benefit from supportive therapy (intravenous fluids, medicine to control fever or pain, etc.) and antibiotics for any secondary bacterial infections that occur.

Vaccine

Routine vaccination against smallpox in the United States ended in 1972. Since it is not known if people who were vaccinated before 1972 still have effective immunity, it is assumed that these persons could become infected.

In people exposed to smallpox, the vaccine can lessen the severity of or even prevent illness if given within 4 days after exposure. At this time, vaccination against smallpox is not recommended to prevent the disease in the general public and therefore is not available. The United States currently has an emergency supply of smallpox vaccine.

The U.S. Government's smallpox response plan

The Centers for Disease Control and Prevention is developing a plan to protect people living in this country in the event there is an outbreak(s) of smallpox. The response plan is based on the methods that were used to eliminate smallpox around the world in the 1970s. It relies on a "ring vaccination" strategy. The plan involves quick identification and isolation of individuals who have or are suspected of having smallpox, and then identifying and vaccinating other people that the infected person lives with or who has been in close contact. The plan is available at CDC's Smallpox Response Plan and Guidelines website.

Workers who would respond to an outbreak would need to be protected. This group includes public health workers, those providing medical care or handling medical waste, laboratory personnel, law enforcement or other public safety personnel, and others. Health care facilities that receive victims need negative pressure isolation rooms and other equipment and procedures for treating patients.

For more information about smallpox visit the Center for Disease Control and Prevention website. 

Plague

Pneumonic plague is an infectious disease caused by the bacterium Yersinia pestis. Y. pestis is found in rodents and fleas in many areas around the world. Person-to-person transmission of pneumonic plague occurs through respiratory droplets, which can only infect those who have face-to-face contact with the ill patient.

Pneumonic plague occurs when Y. pestis infects the lungs. The first signs of illness are fever, headache, weakness, and cough with bloody or watery sputum. The pneumonia progresses over 2 to 4 days and may cause septic shock and, without early treatment, death.

Early treatment of pneumonic plague is essential. Several antibiotics are effective, including streptomycin, tetracycline, and chloramphenicol. Preventive antibiotic treatment for 7 days will protect persons who have had face-to-face contact with infected patients. There is no vaccine against plague.

For more information visit the Center for Disease Control and Prevention website. 

Botulism

Botulism is a disease in which muscles become paralyzed. The disease is caused by a toxin made by a bacterium calledClostridium botulinum. Botulism is not spread from person to person.

Foodborne botulism occurs when a person eats contaminated food. Foodborne botulism is a public health emergency because the contaminated food may still be available to other persons besides the patient. Symptoms begin within 6 hours to 2 weeks (most commonly between 12 and 36 hours) after eating toxin-containing food. Symptoms of botulism include double and blurred vision, drooping eyelids, slurred speech, difficulty swallowing, and dry mouth. Muscle weakness spreads through the body, first in the shoulders and then to the upper arms, lower arms, thighs, calves, etc. Paralysis of breathing muscles can cause a person to stop breathing and die, unless assistance with breathing (mechanical ventilation) is provided. Foodborne botulism can occur in all age groups.

There are two other kinds of botulism. Infant botulism occurs in a small number of susceptible infants each year who have the bacteria in their intestinal tract. Wound botulism occurs when wounds are infected with C. botulinum that releases the toxin.

CDC has a supply of antitoxin against botulism. The antitoxin is effective in reducing the severity of symptoms if administered early in the course of the disease. Most patients eventually recover after weeks to months of supportive care.

For more information go to the Center for Disease Control and Prevention website.

[Information about other diseases can be found at the Bioterrorism Agents/Diseases section of the CDC website or doing a search at the Centers for Disease Control and Prevention. ]