A Technique Employing Embryonated Chicken Eggs for the Infection of Argasid Ticks with Coxiella Burnetii, Bacterium Tularense, Leptospira Icterohaemorrhagiae, and Western Equine Encephalitis Virus

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Abstract
The technique of feeding blood-sucking arthropods through the air-sac membrane of embryonated chicken eggs, as reported by Haas and Ewing (1945) for mosquitoes and by Ferris and Hanson (1952) for mosquitoes and flies, was used successfully for the feeding of argasid ticks of the genus Ornithodoros. Fertile hens'' eggs were incubated at 101oF for 10-12 days and, after the shell above the air sac had been removed, ticks of the spp. O. turicata, O. moubata, O. parkeri, and Q. hermsi as well as the bird tick, Argas reflexus, were placed for feeding on the shell membrane. The eggs were then sealed tightly with cellulose tape and returned to the incubator for 8-12 hrs. It was found that all spp. except A. reflexus fed in varying nos. upon the embryonated eggs. The highest percentage of engorged ticks belonged to O. turicata and O. moubata. In connection with studies of the behavior of pathogenic organisms in argasid ticks, the descr. technique was used for infecting the ticks with certain disease agents which grow well in egg cultures. O. turicata and O. moubata were fed on eggs infected with Coxiella burnetii, Bacterium tularense, Leptospira icterohaemorrhagiae. and western equine encephalitis virus. At varying intervals after the infective feedings, the ticks were tested for their ability to ingest and preserve the micro-organisms. The results obtained to date show the persistence and multiplication of each of these agents in O. turicata as well as in O. moubata. The descr. method of tick feeding on embry-onated chicken eggs may be useful not only for infecting ticks with various agents cultivated in eggs but also for the detection of infected ticks. In transmission studies normal eggs were used to detect relapsing fever spirochetes in O. turicata and O. parkeri.