Rickettsia species are small bacteria that are obligate intracellular parasites. These zoonotic pathogens can disseminate in the blood to most organs and cause infections. Rickettsia species causes Rocky mountain spotted fever, rickettsial pox and other spotted fevers. It was first reported in the Rocky mountain states but occurs throughout the continental United States. It is most prevalent in the south eastern and south-central United States. It also occurs in Central and South America. Infection is spread to human through bites by wood ticks or dog ticks.