Spotted Fever Group
Spotted fever group of rickettsial diseases include:
· Rocky Mountain spotted fever caused by Rickettsia rickettsiae,
Rickettsial pox caused by R.
· Boutonneuse fever (i.e., Kenya tick-bite fever, African tick typhus,
Mediterranean spotted fever, Indian tick typhus, and Marseilles fever) caused
by R. conori.
Rickettsiae of this group possess a common soluble group antigen.
They also multiply in the nucleus as well as in the cytoplasm of the infected
cells. All these species except R. akari
are transmitted by ticks. A total of 12 species of rickettsiae have been
associated with humans causing spotted fever and seven species have been
isolated from arthropod vectors. R.
rickettsiae is the most common species belonging to thespotted fever group
and is responsible for Rocky Mountain spotted fever.