American Q Fever: Experimental Transmission by the Argasid Ticks Ornithodoros moubata and O. hermsi

Abstract

In a continua-tion of a series of studies on the transmission of several disease agents by ticks of the genus Ornithodoros, 3 expts. were performed with O. moubata, using 32, 82, and 76 first nymphs, respectively, for the infective feedings and 2 with O. hermsi, using 35 and 114 first nymphs. Guinea pigs were used for all infective and test feedings. O. moubata failed in transmission until the adult stage was reached and were shown to be infective by feeding up to 428 days following the infective feeding and conserved the agent in its tissues for 670 days, as shown by injn. Transmission through the egg to the F2 generation was demonstrated. Some of the progeny were infective at the 1st test feeding. 0. hermsi caused typical infections at the 2d test feeding and up to 772 days following the infective feeding. The organism was conserved in the tissues for 979 days as shown by injn. In the F1, 100 unfed larvae were proved infective by injn. Man is a host for both species of ticks, O. moubata is the chief tick vector of relapsing fever over a large area in Africa and 0. hermsi is a vector in 6 Western States in the U. S.