Bioterrorism Agents And Barrier Protection

Bacillus anthracis, Anthrax DEFINITION Anthrax is caused by Bacillus anthracis, a gram-positive spore-forming bacterium, and is found in soil worldwide. Humans contract the disease from close contact with animals or animal products infected with the bacteria. Of the three routes of exposure – inhalation, cutaneous, and gastrointestinal – inhalational anthrax is the one that is of greatest concern as a bioweapon.2 Inhaled spores can germinate for up to 60 days in the mediastinal lymph nodes; therefore, the time period between exposure and onset of symptoms may be as long as several weeks. There are three forms of anthrax: Skin (cutaneous) Most common natural form. Mortality of 10% to 20% if untreated; less than 1% when treated. Lungs (inhalation) Most lethal form, with mortality of 45% to 87% following inhalation of spores. Most likely form of the disease to occur in a bioterrorist event. Digestive (gastrointestinal) Rare, but highly fatal form that occurs after ingestion of spores. There is a potential use in a bioterrorist event, which might be seen in an aerosol release.3 Clinical manifestation of the three forms of Anthrax4 Anthrax Incubation Period Early Signs/Symptoms Later Signs/Symptoms Inhalational (primary involvement is the mediastinum) 2-60 days. Flu-like symptoms including fever, malaise, headache, cough, fatigue and anorexia, prominent absence of rhinitis. Fever, chest pain, severe respiratory distress, diaphoresis, shock and death. Cutaneous 1-7 days, possibly up to 12 days. Fever and malaise, small papular or vesicular rash that may be pruritic. Painless ulceration with overlying eschar, localized edema, often on the head, forearms and hands. Gastrointestinal 1-7 days, typically 2-5 days. Fever, abdominal pain, vomiting and bloody diarrhea and headache. Shock and death. DIAGNOSIS There are no specific laboratory tests for inhalation anthrax, but a widened mediastinum with or without infiltrates on chest x-ray is highly suggestive in a young or otherwise healthy person with the typical presentation. Bloody pleural effusions are also common. Basic diagnostic testing should include gram stain and culture of blood, which can be obtained following your facility’s standard routine. If the culture grows gram-positive bacilli, it must be sent to a state laboratory to be analyzed further.5 The state laboratory needs to be notified ahead of time that anthrax is a possibility. The local health department will investigate and give directions on how to obtain and send the cultures. There are no available rapid specific tests for early anthrax disease. B. anthracis can be cultured from the lesion for laboratory confirmation in the cutaneous form. The local health department will need to be notified and provide directions to obtain and send the cultures.6 TREATMENT Treatment consists of hospitalization, intravenous antibiotics, and intensive supportive care. Antibiotic treatment should be administered as soon as the diagnosis is suspected. Early initiation can reduce mortality, which approaches 100% when treatment is delayed. POST-EXPOSURE PROPHYLAXIS Antibiotics should be administered to all persons that have been exposed or potentially exposed to the release of anthrax before symptoms have occurred. Patient contacts (family, friends, and healthcare workers) who were not originally exposed to the release do not require prophylaxis.3,7 VACCINATION A licensed cell-free, effective, and safe vaccine exists, but is currently not available to the general public. INFECTION CONTROL Regardless of the form of the anthrax disease, Standard Precautions are recommended. Standard Precautions Handwashing Wash hands immediately after gloves are removed, between patient contacts, and when otherwise indicated to avoid transfer of microorganisms to other patients or environments. Gloves Wear gloves when touching blood, bodily fluid, secretions, excretions, and contaminated items; put on clean gloves just before touching mucous membranes and nonintact skin. Change gloves between tasks and procedures on the same patient after contact with material that may contain a high concentration of microorganisms. Remove gloves promptly after use, before touching noncontaminated items and environmental surfaces, and before going to another patient.Wash hands immediately to avoid transfer of microorganisms to other patients or environments. Masks, eye protection, face shields Wear a standard surgical mask and eye protection or a face shield to protect mucous membranes of the eyes, nose, and mouth during procedures and activities that are likely to generate splashes or sprays. Several sources recommend Contact Precautions for cutaneous anthrax for persons with draining lesions. Contact Precautions Place patient in a private room. Gloves should be worn when entering the room and removed before leaving the room. Hands should be washed with an antimicrobial agent or a waterless handwashing agent immediately after removing gloves. Gowns should be worn when entering the room if it is anticipated that clothing will have contact with the patient, environmental surfaces, or items in the room. The gown should be removed before leaving the patient’s room. Patient transport should be limited to essential purposes only. Noncritical patient-care equipment should be dedicated whenever possible.

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