Epidemiology – Transmission

• Transmission occurs through:
  • the bite of an infected flea,
  • respiratory droplets, or
  • direct contact with a patient infected with pneumonic plague.
• Transmission by direct skin or mucous membrane contact with tissues and fluids of infected animals is less common.
• Infection via inhalation of infective respiratory droplets or aerosols is rare with naturally occurring plague in the United States, but is the most likely route of transmission in a bioterrorist event.
• Becoming infected via inhalation requires direct and close (within 6 feet) contact with an ill person or animal and has not occurred in the United States for decades.