Rickettsia

Rickettsia is a genus of bacteria that are natural parasites of arthropods like lice, fleas, mites, and ticks. These bacteria are typically rod-shaped or spherical and are gram-negative. They are obligate intracellular parasites, meaning they can only reproduce inside animal cells.1

Rickettsia are transmitted to humans through the bite of an infected arthropod. In some cases, transmission can also occur if arthropod feces are inhaled or enter the skin through abrasions. While most rickettsia primarily infect animals, humans can become infected accidentally, acting as dead-end hosts.1

Notable diseases caused by Rickettsia include Rocky Mountain spotted fever, epidemic typhus, and scrub typhus. These infections often cause fevers and skin rashes. Treatment for rickettsial diseases typically involves broad-spectrum antibiotics.123