BW Agents: Anthrax J.A. Sliman, MD, MPH LCDR MC(FS) USN Preventive Medicine Resident Johns Hopkins Bloomberg School of Public Health

Anthrax Bacillus anthracis –Rod-shaped, gram-positive, sporulating Zoonotic disease of cattle, sheep, and horses Spores are stable and viable for years in soil and water

BW History Easily stabilized = easily deliverable First weaponized by U.S. in early 1950s Weaponized by FSU and disseminated –Iraq (admitted in 1995) –Who else???

BW Significance Easy to cultivate (induced sporulation) Spores are highly resistant to: –Heat, sunlight, most disinfectants Can be produced in wet or dry form –Can be disseminated in aerosol cloud or point source spray devices

Human Disease Normally contracted by handling contaminated animal products or excreta Infection via cutaneous abrasions, inhalation, & ingestion

Cutaneous anthrax Hands and forearms of livestock handlers Initial papule converts to fluid-filled vesicle Vesicle dries and forms a black scab –“anthrax” = Greek for “coal” Can disseminate and become fatal (CFR = 25%)

Intestinal anthrax From ingesting undercooked meat from an infected animal Features are similar to other food poisonings Nearly 100% CFR

Inhalational anthrax Likely form of BW attack Endemic form is known as “Woolsorters’ disease” Presents like atypical pneumonia –100% CFR if untreated

Inhalational anthrax Incubation period = 1-6 days –Depends upon the strain and inhaled dose Gradual, nonspecific onset of fever, malaise, headache, fatigue, dry cough, pleuritic chest pain Often followed by 2-3 days of improvement

Inhalational anthrax CXR may show widened mediastinum (55%) but no obvious infiltrates Gram stain usually (-) at this point Toxin & bacilli detectable in the bloodstream by day 3 post-exposure (along with elevated WBC count)

Inhalational anthrax Improvement period followed by abrupt onset of severe acute respiratory distress Dyspnea, diaphoresis, stridor, cyanosis Death occurs within 36 hours of onset of respiratory distress

Medical Management Nearly 100% fatal after onset of severe respiratory distress regardless of treatment PCN, tetracycline, erythromycin, Cipro –Cipro 400mg bid f4wks Supportive therapy for shock & airway management

Medical Management Standard vaccine is available –3-shot regimen (0, 6, 12 months) Prophylactic therapy for likely exposures –Cipro 400mg bid f4wks –Vaccinate the previously unvaccinated –Give booster shot to those previously vaccinated

Anthrax Flu or atypical pneumonia-like symptoms Widened mediastinum on CXR without infiltrates Cipro 400mg bid f4wks & vaccinate