Rickettsia

Rickettsia is a genus of non-motile, Gram-negative, non-spore-forming, highly pleomorphic bacteria that can present as cocci (0.1 μm in diameter), rods (1–4 μm long), or thread-like (10 μm long). Obligate intracellular parasites, the Rickettsia species are transmitted by numerous types of arthropod, including chigger, ticks, fleas, and lice, and are associated with both human and plant disease.

Taxonomy

The genus Rickettsia is included in the phylum Proteobacteria, class Alphaproteobacteria and family Rickettsiaceae. It was named after Howard Taylor Ricketts (1871–1910), who studied Rocky Mountain spotted fever in the Bitterroot Valley of Montana, USA at the turn of the 20th century.

Pathogenesis

Most Rickettsia species are pathogenic for humans and are transmitted by arthropods such as ticks, fleas, and lice. The pathogenesis of Rickettsia species are often associated with their ability to invade the endothelial cells that line the blood vessels.

Clinical presentation

The clinical presentation of Rickettsia infection can be quite varied, but commonly includes fever, headache, and rash. The severity of disease can range from mild to life-threatening.

Diagnosis

Diagnosis of Rickettsia infection is often based on clinical presentation and is confirmed by laboratory testing, including serology and PCR.

Treatment

Treatment for Rickettsia infection typically includes the use of antibiotics such as doxycycline.

See also

• Rickettsia rickettsii
• Rickettsia prowazekii
• Rickettsia typhi
• Rickettsia conorii
• Rickettsia africae
• Rickettsia australis
• Rickettsia akari
• Rickettsia felis
• Rickettsia sibirica
• Rickettsia heilongjiangensis
• Rickettsia japonica
• Rickettsia canadensis

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  Rickettsia rickettsii