Staphylococcal enterotoxin B exposure - Pulmonary
SEB is classified as a Category B bioterrorism agent by the CDC. Category B agents are those that are moderately easy to disseminate, result in moderate morbidity rates and low mortality rates, and require specific enhancements of the CDC's diagnostic capacity and enhanced disease surveillance. If used as a bioterrorism agent, SEB would most likely be dispersed as an aerosol producing an incapacitating but rarely lethal pulmonary and systemic syndrome. SEB was weaponized by the United States in the 1960s as an incapacitating agent. Via inhalation, the LD50* for SEB is approximately 0.02 µg/kg.
Whether acquired naturally or as a result of a bioterrorist attack, if SEB is ingested the symptoms include nausea, vomiting, diarrhea, and abdominal pain/cramps. If SEB is inhaled, it presents with sudden onset of high fever (39.5-41 degrees Celsius), myalgias, chills, non-productive cough, and headache. Conjunctivitis may also be noted. The fever may last 2-5 days and the cough may last for up to 4 weeks.
In a bioterrorist attack, inhalation of higher concentrations may result in more severe symptoms such as dyspnea, chest pain, pulmonary edema, and/or ARDS. The incubation period of ingested SEB is 4-10 hours; inhaled SEB is 3-20 hours.
*LD50 (LD = lethal dose) is the amount of a material, given all at once, that causes death in 50% of people.
A05.0 – Foodborne staphylococcal intoxication
419488004 – Staphylococcus aureus enterotoxin B
Differential Diagnosis & Pitfalls
- Unlike inhalational anthrax, pneumonic plague, tularemia, and Q fever, which progressively and rapidly worsen if left untreated, SEB poisoning reaches a clinically stable plateau.
- Vesicant exposure (mustard exposure, lewisite exposure, phosgene oxime)
- Pulmonary agent poisoning
- Hydrogen fluoride
- Hydrogen sulfide
- Ricin or abrin exposure
- Trichothecin (T2) mycotoxin