Biological Weapons --
Staphylococcal Enterotoxin B



SEB is the second most common source of outbreaks of food poisoning. Often these outbreaks occur in a setting such as a church picnic or other community event, due to common source exposure in which contaminated food is consumed.

Although an aerosolized Staphylococcal Enterotoxin B toxin weapon would not likely produce significant mortality, it could render 80% or more of exposed personnel ill and unable to function for 1-2 weeks. The demand on the medical and logistical systems could be overwhelming. As a BW agent, this toxin could be used to sabotage food or small volume water supplies. For these reasons, SEB was one of the 7 biological agents stockpiled by the US during its old bioweapons program, which was terminated in 1969.
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Symptoms





After exposure, symptoms begin in 2-12 hours. Mild-to-moderate exposure produces nonspecific systemic illness characterized by fever, chills, headache, nausea, vomiting, breathing difficulties, chest pain, muscle pain, and a nonproductive cough. Fever, which may reach 103-106oF, lasts 2-5 days, but cough may persist 1-4 weeks. Severe exposures can lead to a toxic shocklike picture and even death.

In mild-to-moderate cases, the physical examination is typically unremarkable. In severe instances, a rattling in the throat is common from pulmonary edema. Depending on the severity of exposure, duration of illness varies from 3-10 days.


How does it spread? Ingesting food, milk, or milk products containing preformed toxin.

Diagnosis Diagnosis can be difficult and is made primarily by clinical and epidemiologic methods. Physical findings nonspecific. In severe exposures with significant pulmonary symptoms, a chest radiograph may show interstitial edema.

Enterotoxin is a stable protein that can be collected from serum if performed quickly. However, by the time symptoms are noted, the detection of toxin is unlikely. SEB accumulates in urine and may be detected for several hours following exposure. If the source of infection is from an inhalation injury, the toxin may be isolated from nasal swabs for up to 12-24 hours.

Treatment
Treatment is limited to aiding breathing for inhalation exposure. Supportive care is the mainstay of treatment. Close attention to oxygenation and hydration are important. Patients with severe SEB may need ventilator support and diuretics. Most patients are expected to do well after the initial phase, but the time to full recovery may be prolonged.

Passive immunotherapy agents have demonstrated some promise when given within 4 hours of exposure, but such therapy is still being tested.

Acetaminophen for fever, and cough suppressants may make the patient more comfortable.

Vaccine
No vaccine available though human trials are ongoing. Passive immunotherapy agents have shown some promise when given within 4 hours of exposure, but such therapy is being tested.

Mortality
No specific data available.


Sources:

USAMRIID's Medical Management of Biological Casualties Handbood; Fourth Edition February 2001; pages 9-10; http://usamriid.detrick.army.mil/education/bluebook/bluebook.pdf
Federation of American Scientists; http://www.fas.org/nuke/intro/bw/agent.htm
Virtual Naval Hospital: Treatment of Biological Warfare Agent Casualties; http://www.vnh.org/FM8284/index.html

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