RMSF is caused by which organism?

RMSF is caused by which organism?

• A. Rickettsia prowazekii
• B. Rickettsia rickettsii
• C. Borrelia burgdorferi
• D. Ehrlichia chaffeensis

Answer: (B)

RMSF is a tick-borne illness caused by Rickettsia rickettsii, a Gram-negative, obligate intracellular bacterium in the spotted fever group. It is transmitted to humans by Dermacentor ticks. The illness typically presents with fever and severe headache, followed by a rash that begins on the wrists and ankles and can spread to the trunk, sometimes involving the palms and soles. The other organisms listed are responsible for different diseases: Rickettsia prowazekii causes epidemic typhus; Borrelia burgdorferi causes Lyme disease; Ehrlichia chaffeensis causes ehrlichiosis. Thus, Rickettsia rickettsii is the organism that causes RMSF.

RMSF is a tick-borne illness caused by Rickettsia rickettsii, a Gram-negative, obligate intracellular bacterium in the spotted fever group. It is transmitted to humans by Dermacentor ticks. The illness typically presents with fever and severe headache, followed by a rash that begins on the wrists and ankles and can spread to the trunk, sometimes involving the palms and soles. The other organisms listed are responsible for different diseases: Rickettsia prowazekii causes epidemic typhus; Borrelia burgdorferi causes Lyme disease; Ehrlichia chaffeensis causes ehrlichiosis. Thus, Rickettsia rickettsii is the organism that causes RMSF.