[Study of a "Rickettsiella" (Rickettsia) pathogen of the spider "Pisaura mirabilis" (author's transl)].

A rickettsiella-like organism has been described in the spider Pisaura mirabilis Cl., and placed into the genus Rickettsiella on the basis of its cycle and ultrastructure. A chlamydial cycle takes place in the digestive cells and becomes more complex in the interstitial cells where giant bodies appear. The latter have been considered up to now as caracteristic of the genus Rickettsiella but, in fact, seem to be in relation with the metabolism of the parasitized cell. Consequently their presence and structure can no longer be retained as specific characters. A study of the host and tissue specificity of the various Rickettsiella actually known must be defined forehand the impact of the metabolism of host cells on the appearance and structure of these bodies.