Annual

Incidence of

Plague in U.S.

Annual

Incidence of

Plague in U.S.

Arthropod-Borne Transmission of Plague

Fleas required for perpetuation of plague vary greatly in vector efficiency and host range

Organisms ingested during blood meal from bacteremic host

Coagulase of flea may cause fibrin clot of organism in stomach which fixes to spines of proventriculus (throat parts of flea)

Organisms multiply causing blockage

Flea regurgitates infectious material into new host during subsequent attempts at blood meal

Flea remains hungry & feeds more aggressively

Sudden eradication of rats could lead to outbreak

Yersinia

Summary

Table

Yersinia

Summary

Table (cont.)

REVIEW