text: Transmission can occur in multiple ways. One way to contract the infection is through contact with an infected host's feces. If an infected host's feces come into contact with an open skin barrier, it is possible for the disease to be transmitted. An uninfected host can become infected when eating food that contains the feces of the infected vector. Another way of contraction is by the bite of an infected tick. After getting bitten by an infected tick, R. rickettsiae are transmitted to the bloodstream by tick salivary secretions.
  Having multiple modes of transmission ensures the persistence of R. rickettsii in a population. Additionally, having multiple modes of transmission helps the disease adapt better to new environments and prevents it from becoming eradicated. R. rickettsii has evolved a number of strategic mechanisms, or virulence factors, that allow it to invade the host immune system and successfully infect its host.
  Physiology
  Metabolic Pathways
  R. rickettsii are obligate intracellular bacteria, meaning they need a host cell in order to replicate and survive. This is due to the pathogen having many metabolic deficiencies and having to borrow metabolites from the host cell. R. rickettsii is unable to utilize glycolysis and the pentose phosphate pathway due to a reduced genome, and since these pathways are unusable, the bacterium must use the tricarboxylic acid cycle (TCA) as an alternative pathway. However, this can only be done through the use of the host cell's metabolites. This is possible because cell envelope glycoconjugates are synthesized using three particular sugars found in host cells, along with the other metabolites that are acquired from the host cell that will fuel the TCA Cycle.