Interaction between Dermacentor reticulatus cells and Coxiella burnetii in vivo.

By electron microscopy the distribution of Coxiella burnetii was followed in females of Dermacentor reticulatus injected intracoelomally in a dose of about 10(3) EID50 per tick. The heaviest infestation with coxiellae was noticed in the cells of haemolymph, fat body, Malpighian tubulus and tracheal complex. No rickettsiae were found in Gene's organ. Unexpected was the propagation of rickettsiae in muscle fibres. C. burnetii multiplied in all organs affected. Heavy infection resulted at the marked damage of cell components. Coxiellae were evident in the haemocytes; in organs they formed small and large cell variants; endospore formations were observed free in the haemolymph.