Warfare Agents–Biological
Biological weapons have been used since antiquity, with documented cases dating back to the 6th century bc, when the Assyrians poisoned wells with ergots. In the late 1930s and early 1940s, the Japanese Army (Unit 731) experimented on prisoners of war in Manchuria with biological agents that are thought to have resulted in at least 10,000 deaths. Although in 1972 over 100 nations signed the Biological Weapons Convention (BWC), both the former Soviet Union and Iraq have admitted to the production of biological weapons, and many other countries are suspected of continuing their programs. Today, bioweapons are considered the cheapest and easiest weapons of mass destruction to produce. Some agents (Table II–58) that are thought to be likely to be used include Bacillus anthracis (anthrax), Yersinia pestis (plague), Clostridium botulinum toxin (botulism), Variola major (smallpox), and Francisella tularensis (tularemia). All these agents can be weaponized easily for aerial dispersion.
Agent | Mode of Transmission | Latency Period | Clinical Effects |
|---|---|---|---|
Anthrax | Spores can be inhaled or ingested or cross the skin. No person-to-person transmission, so patient isolation not required. Lethal dose estimated to be 2500–50,000 spores. | Typically 1–7 days, but can be as long as 60 days | Inhaled: fever, malaise; dyspnea, nonproductive cough, hemorrhagic mediastinitis; shock. |
Ingested: nausea, vomiting, abdominal pain, hematemesis or hematochezia, sepsis. | |||
Cutaneous: painless red macule or papule enlarging over days into ulcer, leading to eschar; adenopathy; untreated may lead to sepsis. | |||
Treatment: ciprofloxacin, other antibiotics (see text); anthrax vaccine. | |||
Plague | Inhalation of aerosolized bacteria or inoculation via flea bite or wound. Victims are contagious via respiratory droplets. Toxic dose 100–500 organisms. | 1–6 days | After aerosol attack, most victims would develop pulmonary form: malaise, high fever, chills, headache; nausea, vomiting, abdominal pain; dyspnea, pneumonia, respiratory failure; sepsis and multiple-organ failure. Black, necrotic skin lesions can result from hematogenous spread. Skin buboes otherwise unlikely unless bacteria inoculated through skin (eg, flea bite, wound). |
Treatment: tetracyclines, aminoglycosides, other antibiotics (see text); vaccine not available. | |||
Smallpox | Virus transmitted in clothing, on exposed skin, as aerosol. Victims most contagious from start of exanthem. Toxic dose 100–500 organisms. | 7–17 days | Fever, chills, malaise, headache, and vomiting, followed 2–3 days later by maculopapular rash starting on the face and oral mucosa and spreading to trunk and legs. Pustular vesicles are usually in the same stage of development (unlike those of chickenpox). Death in about 30% from generalized toxemia. |
Treatment: vaccinia vaccine, immune globulin (see text). | |||
Tularemia | Inhalation of aerosolized bacteria, ingestion, or inoculation via tick or mosquito bite. Skin and clothing contaminated. Person-to-person transmission not reported. Toxic dose 10–50 organisms if inhaled. | 3–5 days (range, 1–14 days) | Inhalation: fever, chills, sore throat, fatigue, myalgias, nonproductive cough, hilar lymphadenopathy, pneumonia with hemoptysis and respiratory failure. |
Skin: ulcer, painful regional adenopathy, fever, chills, headache, malaise. | |||
Treatment: doxycycline, aminoglycosides, fluoroquinolones (see text); investigational vaccine. | |||
Viral hemorrhagic fevers | Variety of routes, including insect or arthropod bites, handling contaminated tissues, and person-to-person transmission. | Variable (up to 2–3 weeks) | Ebola virus, Marburg virus, arenavirus, hantavirus, several others; severe multiple-system febrile illness with shock, delirium, seizures, coma, and diffuse bleeding into skin, internal organs, and body orifices. |
Treatment: None. Isolate victims, provide supportive care. | |||
Botulinum toxins | Toxin aerosolized or added to food or water. Exposed surfaces may be contaminated with toxin. Toxic dose 0.01 mcg/kg for inhalation and 70 mcg for ingestion. | Hours to a few days | See Botulism Related posts:
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