ABSTRACT
This chapter considers four aspects of the rickettsia-host interaction: pathogenesis, reactivation, immunity, and interference. Rickettsiae differ from one another in their ecologic niches and mechanisms of maintenance in nature. Human infection with pathogenic rickettsiae may have one of three outcomes: killing of the rickettsiae by the immune system, rickettsial suicide by killing its human host, or establishment of a chronic, latent infection. The pathogenesis of rickettsioses is important to humans since the pathogenic details offer a series of steps where the diseases might be blocked. Immune and phagocytic mechanisms that rid the vertebrate host of rickettsial organisms that have established a disseminated endothelial infection are important aspects of the rickettsia-host interaction. Rickettsiology abounds with intriguing phenomena, e.g., reactivation, release from the host cell, interferon-gamma inhibition, interference, and mouse toxicity, the mechanisms of which are awaiting experimental inquiry.
