Spotted Fever Group

Spotted Fever Group

Spotted fever group of rickettsial diseases include:

·     Rocky Mountain spotted fever caused by Rickettsia rickettsiae,

·           Rickettsial pox caused by R. akari, and

·        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.