Periodontitis significantly decreases survival in hemodialysed patients with end stage renal disease (ESRD). Periodontitis-related microorganisms spreading into the bloodstream are thought to impair blood rheological parameters - for example, increasing whole blood viscosity, aggregating blood elements, and decreasing blood flow - and thereby significantly accelerate systemic or local diseases, impairing survival. We discuss the ability of a prototypical pathogenic anaerobic polybacterial consortium to modulate and interfere with host immune responses and to enzymatically degrade host proteins, to bind to and cleave extracellular matrix proteins, to invade intercellularly as well as intracellularly, to promote vascular permeability, to disrupt polymorphonuclear leukocyte function, to cleave complement, and to degrade IgG heavy chains. To further elucidate these phenomena, studies involving detecting microorganism byproducts and monitoring blood rheological parameters are necessary.