Bioterorism—are you ready for the silent killer? - Home Study Program

AORN Journal,  Sept, 2002  by Kristina Stillsmoking

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BIOLOGICAL AGENTS AS WEAPONS

There are four category A agents of major concern that officials have identified as potential agents for a bioterrorism attack. These include

* anthrax (ie, Bacillus anthracis),

* smallpox (ie, variola major),

* plague (ie, Yersiniapestis), and

* botulism (ie, Clostridium botulinum toxin). (11)

There are other category A agents of interest, but they are not the major focus of public education at this time.

Anthrax (ie, Bacillus anthracis). Anthrax is highly lethal if it is not diagnosed and treated within 24 to 36 hours of onset of severe symptoms. Incubation generally occurs within one to six days, but it has been found to appear 60 days postexposure in test animals. Bacillus anthracis is a grampositive spore-forming rod that has been known to survive in the soil for more than 100 years, and it exists worldwide. Anthrax also is known as the wool sorter's disease because it exists naturally in infected sheep, cattle, and horses. The flu-like symptoms indicative of anthrax may include high fever, fatigue, cough, malaise, and mild chest discomfort progressing to respiratory distress, cyanosis, diaphoresis, dyspnea, stridor, and shock. (12) A nonspecific physical finding late in the illness is a widened mediastinum as seen on a chest x-ray. Additionally, a gram stain of blood and blood culture detects the bacillus. Patients should receive high dose antibiotic treatment with ciprofloxacin or doxycycline before the onset of symptoms. Use of dual antibiotics is recommended to control the ensuing possibility of meningitis. The same treatment is used with the onset of symptoms, although it has limited effectiveness. In addition, the same supportive measures are used.

A vaccine for anthrax does exist but only limited quantities are available, so its use is limited to military purposes. The vaccination process includes six injections given during the course of one year with an annual booster. Prophylaxis in cases when exposure is known and verified includes oral ciprofloxacin or doxycycline, although several antibiotics with similar abilities are being investigated currently.

As an agent of bioterrorism, the method of exposure to anthrax would be airborne or via contact with inanimate objects (eg, mail, wool). Standard precautions for health care workers should be practiced when caring for patients infected with anthrax because no person-to-person transmission has been documented. Any areas or instruments needing cleaning should be disinfected with a sporicidal agent (eg, phenol, hypochlorite).

Smallpox (ie, variola major). The smallpox variola virus has a 70% survivability rate with an incubation period of seven to 10 days. Patients with smallpox may experience flu-like symptoms, including fever, vomiting, headache, rigors, backache, and malaise. Within two to three days, lesions appear that progress quickly from macules to papules and eventually pustular vesicles. These lesions develop synchronously and are more abundant over the extremities and face. They are unlike chickenpox, which develops first on the trunk of the body and is seen in various stages of development. (13)