- Bites from infected rodent fleas
- Direct contact with infected tissue or bodily fluids
- Inhaling infected droplets.
(Click Plague Transmission for more information.)
Incubation PeriodWhen a person becomes infected with the bacteria that cause plague, the bacteria begin to multiply within the body. For bubonic plague, this occurs in the lymph system; for pneumonic, this occurs within the lungs. (The lymph, or lymphatic system, is a major component of your body's immune system. The organs within the lymphatic system are the tonsils, adenoids, spleen, and thymus.) After 1 to 6 days, symptoms can begin. The period between becoming infected and the start of symptoms is called the incubation period.
(Click Plague Incubation Period for more information.)