Ultrastructure and distribution of intracellular rickettsia-like microorganisms in various organs of the laboratory-reared adult tick Argas (Persicargas) arboreus (Ixodoidea: Argasidae).

Rod (RS) and coccoid (CS) rickettsia-like microorganisms were found in single and group forms in organs of the laboratory-reared adult ticks Argas (Persicarges) arboreus. RS are distributed in most organs but are mainly concentrated in the salivary glands, mid-gut, and testes. CS single forms were concentrated in the rectal sac, while the group forms were limited to Malpighian tubules and haemocytes of both sexes. The primary oocytes were heavily infected with both forms of CS. No RS or CS were detected in the muscles. Despite the structural differences between RS and CS, they are suggested to be different morphotypes of the same organism.