RMSF is transmitted by which vector?

• A. Lice
• B. Mosquitoes
• C. Ticks
• D. Fleas

Answer: (C)

RMSF is a tick-borne infection caused by the bacterium Rickettsia rickettsii. A vector is the organism that transmits a pathogen to a new host, and for RMSF that vector is ticks—specifically hard ticks such as Dermacentor species. The bacteria are transmitted to a person when an infected tick attaches and feeds, delivering the pathogen through its saliva. Other common vectors like lice, fleas, or mosquitoes transmit different diseases, so they’re not responsible for RMSF. Understanding that RMSF is tick-borne helps emphasize prevention: avoid tick exposure, use protective clothing and repellents, and check for and remove ticks promptly after being outdoors.