Expertise in dealing with biological weapons requires specific knowledge from the fields of infectious disease, epidemiology, toxicology, and public health. Biological and chemical warfare agents share many characteristics in common, including intent of use, some dispersion methods, and initial defense based on adequate personal protective equipment and decontamination (see Tables 131–2 and 131–3). Key differences between biological and chemical weapons, however, involve a greater delay in onset of clinical symptoms after exposure to biological weapons; that is, the incubation period for most biological warfare (BW) agents is greater than the latent period for most chemical warfare (CW) agents. Decontamination is less crucial for victims exposed to BW agents than to CW agents. Additionally, a few BW agents can reproduce in the human host and cause secondary casualties, and disease following exposure to several of these agents can be prevented by the timely administration of prophylactic medications.
Biological weapons may be bacteria, fungi, viruses, or toxins derived from microorganisms. Some fungi are listed as potential BW agents, although to date, none are known to have been developed into weapons.84 Because toxin weapons do not contain living organisms, some authorities classify them as chemical, rather than biological, weapons. For the purposes of discussion in this chapter, toxin weapons derived from microorganisms will be considered biological weapons. Most of the bacterial BW agents exert their effects by elaborating protein toxins.
A majority of the diseases caused by biological weapons are either infrequently encountered in modern clinical medicine, such as anthrax and plague, or no longer occur naturally, such as smallpox. Healthcare personnel therefore require specific training in the recognition and management of biological warfare victims. Potential BW agents have been categorized by the risk of mass-casualty outbreaks resulting from deployment and exposure.17 The high-risk agents are easily disseminated or transmitted and may cause high mortality and potentially a public health disaster; these agents include smallpox, anthrax, plague, botulism, tularemia, and several hemorrhagic fever viruses. The moderate-risk agents include Q fever, brucellosis, the equine encephalitis viruses, ricin, and staphylococcal enterotoxin B, all of which are briefly discussed in this chapter.
Biological warfare has ancient roots. Missile-type weapons poisoned with natural toxins were used as early as 18,000 years ago (Chap. 1). Excavation of an Egyptian tomb, from about 2100 B.C., yielded arrows coated with cardioactive steroids and paralytic toxins.62 The first recorded intentional spread of infectious disease in warfare occurred in the Anatolian war of 1320–1318 B.C. and appears to have involved tularemia.81 Around 600 B.C., the Athenians used hellebore, and the Assyrians used ergot alkaloids, to poison enemy water supplies. In 200 B.C., the Carthaginian general Maharbal tainted wine consumed by African rebel forces with the anticholinergic herb mandragora and then ambushed the intoxicated troops. In 184 B.C., Hannibal ordered earthen pots filled with "serpents of every kind" hurled onto enemy ships, thereby winning the naval battle of Eurymedon against ...