Houseflies have found a way to thrive in septic conditions where other organisms including dipterans would perish. The housefly is one of the most widely distributed insects on the planet and therefore serves as a vector of disease worldwide. Proteus vulgaris, a ubiquitous gram-negative bacterium was isolated from wild flies during a survey at a S.E. Georgia animal shelter in the fall of 2006. Derived from the current survey and literature, it is known that the housefly and P. vulgaris share environments. The persistence of P. vulgaris in orally fed houseflies will be determined as well as the immune response of the housefly with oral ingestion of P. vulgaris. Gnotobiotic houseflies will be fed a minimum infective dose of P. vulgaris and evaluated for bacterial levels at set timepoints (2, 6, 12 and 24 hours); these levels will be correlated with relative levels of cecropin and defensin, two genes associated with the humoral immunity in the housefly.