Signs and Symptoms: Symptoms usually begin with cranial nerve palsies, including ptosis, blurred vision, diplopia, dry mouth and throat, dysphagia, and dysphonia. These findings are followed by symmetrical descending flaccid paralysis, with generalized weakness and progression to respiratory failure. Symptoms begin as early as 12-36 hours after inhalation, but may take several days to develop after exposure to low doses of toxin.
Diagnosis: Diagnosis is primarily clinical. Biological agent attack should be suspected if multiple casualties simultaneously present with progressive descending flaccid paralysis. Laboratory confirmation can be obtained by bioassay (mouse neutralization) of the patient’s serum. Other helpful assays include enzyme-linked immunosorbent assay (ELISA) or electrochemiluminescence (ECL) for antigen in environmental samples, polymerase chain reaction (PCR) for bacterial DNA in environmental samples, or nerve conduction studies and electromyography.
Treatment: Early administration of trivalent licensed antitoxin or heptavalent antitoxin (IND product) may prevent or decrease progression to respiratory failure and hasten recovery. Intubation and ventilatory assistance is needed for respiratory failure. Tracheostomy may be required for long-term airway maintenance.
Prophylaxis: Pentavalent toxoid vaccine (which protects from types A, B, C, D, and E (although potency concerns for B - E); but not F or G) is available as an IND product for those at high risk of exposure. Because the original toxoid components were produced in 1970, recent evidence suggests that immunologic protection for serotypes B through E may not be adequately obtained with this currently available pentavalent toxoid vaccine.
Isolation and Decontamination: Standard precautions for healthcare workers. Botulinum toxin is not dermally active and secondary aerosols are not a hazard from patients. Decontaminate with soap and water. Botulinum toxin is inactivated by sunlight within 1-3 hours. Heat (80OC for 30 min, 100OC for several minutes) and chlorine (>99.7% inactivation by 3 mg/L FAC in 20 min) also destroy the toxin.
USAMRIID's Medical Management of Biological Casualities Handbook. Sixth ed. Fort Dietrich, Maryland: U.S. Army Medical Research Institute of Infectious Diseases, 2005. 86.
