Septicemic Plague - Transmission and Mode of Action

Transmission and Mode of Action

The disease is contracted primarily through the bite of an infected rodent or insect, but like bubonic plague can very rarely be contracted through an opening in the skin or by cough from another infected human. After initial infection, the bacteria multiply in the blood, causing bacteremia and severe sepsis. In septicemic plague, bacterial endotoxins cause disseminated intravascular coagulation (DIC), where tiny blood clots form throughout the body, possibly resulting in ischemic necrosis (tissue death due to lack of circulation/perfusion to that tissue).

DIC results in depletion of the body's clotting resources, so that it can no longer control bleeding. Consequently, there is bleeding into the skin and other organs, leading to red and/or black patchy rash and hemoptysis/hematemesis (respectively coughing up or vomiting up of blood). There are bumps on the skin looking somewhat like insect bites; these are usually red, and sometimes white in the center.

Untreated, septicemic plague is usually fatal. Early treatment with antibiotics reduces the mortality rate to between 4 and 15 percent. People that contract this disease must receive treatment in at most 24 hours, or death is almost inevitable. In some cases, people may even die on the same day they contract it.