The Family Rickettsiaceae contains two Genera of human pathogens, Rickettsia and Ehrlichia. The usual cycle is between arthropods and wild animals.
Humans just get into the territory and get bitten.
The organism is taken up from one host by the arthropod vector and injected into the bloodstream of the next host. The three diseases listed here as rickettial diseases are all manifested as fever, headache, and rash. Laboratory diagnosis is usually achieved through clinical presentation and history and possibly serological or PCR testing rather than growing the organism. The organisms are very infectious and risk of laboratory accidental infection is high. Tetracylines are drugs of choice.