Caused by Yersinia pestis, non-motile, gram-negative bacillus.
Naturally occurring plague is spread by the bite of infected fleas.
Enzootic among rodents in the western US.
Humans can be infected via the bite of an infected flea carried by a rodent, or rarely other animals, direct contact with contaminated tissues, or rarely inhalation of respiratory secretions from infected persons or animals.
Majority of patients with Yersinia pestis infection have no cutaneous lesion.
The bubo characteristic of plaque is tender and associated with rapid progression of infection.
Caused approximately 14 million deaths in Europe in the 14th century.
Hundreds of cases occur annually throughout the world.
An estimated 1000-2000 cases occur annually worldwide.
As a zoonotic disease which in endemic areas it circulates among squirrels, chipmunks, deer mice and other animals.
Transmission to man from wild animals is rare.
Y. pestis produces an endotoxin and dissemination of the bacteria results in intravascular coagulation and endotoxic shock with necrosis of the extremities resulting in the name “black death”.
Three clinical forms: bubonic, septicemic and pneumonic.
Moxifloxacin an approved antibacterial agent.