Multigeneration Cross-Contamination of Mail with Bacillus anthracis Spores

Area of Science:

• Microbiology
• Public Health
• Biosecurity

Background:

• Biological agent release in urban areas is a long-standing security concern.
• Previous incidents highlight the need to understand Bacillus anthracis spore spread.
• Morphological differences between Bacillus species may affect spore adhesion and transfer.

Purpose of the Study:

• To evaluate the cross-contamination potential of Bacillus anthracis spores during simulated mail handling.
• To assess the impact of envelope generation and fluidizers on spore transfer.

Main Methods:

• Utilized specialized equipment to simulate mail handling processes, including tumbling and mixing.
• Tested three generations of envelopes to assess cross-contamination over time.
• Investigated the effect of a fluidizer on spore transfer and reaerosolization.

Main Results:

• Cross-contamination varied significantly between different generations of envelopes.
• The presence or absence of a fluidizer did not statistically impact material transfer.
• Fluidizers had no significant effect on cross-contamination levels or reaerosolization upon letter opening.

Conclusions:

• Simulated mail handling can lead to Bacillus anthracis spore cross-contamination, with variability across envelope types.
• Fluidizers are ineffective in mitigating spore transfer or reaerosolization in this context.
• Findings are crucial for developing effective strategies against bioterrorism threats via mail.