In 1979, an accident involving aerosolized anthrax spores at a Soviet bioweapons military compound resulted in fever, respiratory difficulty, and over 60 fatalities in civilians living downwind from the facility. Anthrax has been weaponized by other countries as well. A recent hoax involving the delivery of a leaking package to the B'nai B'rith Center in Washington, D.C., labeled "Anthrachs" resulted in temporary yet serious disruption of that city's activities. This incident has been followed by numerous similar threats in many areas of the United States such that anthrax threats have become the "bomb scares" of the late 1990s. The problem is that such threats must be taken seriously, at least initially, since this organism is potentially so deadly. Early expert consultation is critical in such situations to assess whether a legitimate threat to health exists (i.e., biologic agents are nonvolatile and generally not dermally active, so if there is no aerosol generated, then there usually is no credible threat). Soap and water decontamination generally is adequate in this type of scenario, and postexposure antibiotic therapy usually can be delayed for up to 24 h to allow time for determining whether a lethal agent is indeed present.
Anthrax spores are stable and relatively easy to cultivate. Dispersion by a line source of 50 kg of spores over a population of 500,000 has been estimated to result in up to 220,000 people killed or seriously incapacitated. Infectious spores germinate and elaborate toxins that result in tissue edema and necrosis. Various forms of this zoonosis exist in nature. Most commonly, human illness is acquired by handling animal fluids or pelts. Following skin inoculation, the developing "malignant pustule" has an untreated mortality of 25 percent and a treated mortality of less than 1 percent. Gastrointestinal and inhalational forms of illness, as in an aerosol attack, have nearly 100 percent mortality if not treated within 24 to 48 h.
A WMD attack would likely result from inhalation of anthrax spores or "Woolsorter's disease." An incubation period of 1 to 6 days is seen, followed by fever, myalgia, cough, chest pain, and fatigue. Transient improvement may be noted after 1 to 2 days of symptoms but is followed by abrupt onset of sepsis, hypotension, and death in 24 to 36 h. Hemorrhagic meningitis occurs in 50 percent of patients. The disease does not involve the lung parenchyma but instead causes a necrotizing hemorrhagic mediastinitis. The chest x-ray in late stages is characteristic, with significant mediastinal widening, pleural effusion, but no infiltrates. The diagnosis in most laboratories rests on Gram stain and blood cultures for the bacillus (not spores) late in the illness. Other methods of confirmation are available in some laboratories. Treatment involves ciprofloxacin 400 mg IV every 8 to 12 h or doxycycline 100 mg IV every 12 h. Others exposed, even if asymptomatic, should be started on either of the preceding antibiotics orally for 4 weeks while being immunized with three doses of vaccine after exposure. A licensed vaccine exists and is currently administered to U.S. soldiers. It is safe (side effects are local and self-limited) and is extremely effective in animal studies, providing protection against high-dose aerosol exposures to virulent strains. Standard precautions in caring for a patient with anthrax are recommended. There are no known cases of human-to-human transmission of inhalation anthrax. Iodine or hypochlorite at disinfectant strengths is required to destroy spores on equipment, although a dilute (1:9) household bleach solution is recommended to decontaminate victims immediately after exposure. Soap and water are probably adequate decontamination for human skin as well.
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.