The vector potential of adult house flies, Musca domestica L., for Yersinia
pseudotuberculosis (Pfeiffer), a pathogen of domestic animals and humans,
was investigated. Adult flies were allowed to feed on trypticase soy broth
(TSB) containing Y. pseudotuberculosis for 6 h and then transferred to ster
ile containers with sterile TSB as a source of water and nutrients. At 6-h
intervals, all flies were transferred to sterile containers with sterile TS
B and 10 randomly selected flies were examined for the pathogen. Yersinia p
seudotuberculosis did not establish a permanent population in the house ny
colony; however, viable cells were detected from the digestive tract of fli
es for up to 36 h after the initial exposure, and flies contaminated their
environment (sterile TSB) for up to 30 h after the exposure. These results
demonstrated that house flies can carry Y. pseudotuberculosis for a conside
rable period and therefore must be considered as a potential mechanical vec
tor of pseudotuberculosis infection.