Q Fever Studies in Southern California: I. Recovery of Rickettsia burneti from Raw Milk

Abstract

Strains of R burneti were isolated from raw milk from 4 dairies in Southern California located in endemic areas. Raw milk was inoculated into adult guinea pigs, blood and spleen from sick animals were passed to other guinea pigs, the strains were established in mice and in fertile hens eggs and identified by immunologic comparison with known strains of the Q fever rickettsia. No isolations were obtained from blood, urine or feces of the cows, and the animals showed no clinical symptoms. There was no evidence that outbreaks of Q fever were due to drinking raw milk but this source could not be excluded. Preliminary studies indicated that the rickettsiae of Q fever were destroyed by pasteurization.