Tick Transmitted Organisms Quiz

Study Notes

Borrelia burgdorferi is a tick-transmitted organism that causes Lyme disease.
Rickettsia rickettsii is a tick-transmitted organism that causes Rocky Mountain Spotted Fever.
Rickettsia typhi is a flea-transmitted organism that causes murine typhus.
Rickettsial organisms are gram-negative bacteria that can be identified using the Weil-Felix test, which detects cross-reactions with Proteus vulgaris.
Atypical rickettsial infections cannot be cultured, so diagnosis requires PCR or serological testing. Atypical cases often present with a centripetal maculopapular rash that starts peripherally on the ankles and wrists and spreads to the trunk.
Brill-Zinsser disease is a recrudescent form of epidemic typhus caused by Rickettsia prowazekii.
Q fever is caused by Coxiella burnetii, which is usually unable to be cultured.
Leptospira interrogans is a spirochete that causes Weil's disease (liver and renal failure), which is often associated with contact with rats or livestock.
Leptospirosis can manifest as either icteric or anicteric disease and can be diagnosed using serology, specifically the Leptospira Microscopic Agglutination Test (LMAT), and by culturing blood, CSF, or urine.
Atypical rickettsial infections can be treated with doxycycline or macrolides.

Spirochetes are gram-negative spiral-shaped bacteria.
Treponema pallidum is a spirochete that causes syphilis.
Borrelia burgdorferi is a spirochete that causes Lyme disease. Lyme disease can present with erythema migrans (a characteristic rash), arthritis, and facial nerve palsy.
Leptospira interrogans is a spirochete that causes Weil's disease.

Borrelia burgdorferi, Rickettsia rickettsii, Rickettsia typhi are examples of tick transmitted organisms
Rickettsial organisms are gram-negative bacilli
Rickettsia rickettsii causes Rocky Mountain Spotted Fever
Rickettsia typhi causes murine typhus
Rocky Mountain Spotted Fever is a tick-borne illness
Murine typhus is a flea-borne illness
Rickettsial organisms are often diagnosed by PCR or serology
Weil-Felix test can be used to identify Rickettsial organisms
Weil-Felix test detects cross-reaction with Proteus vulgaris

Atypical organisms cannot be cultured
Atypical organisms are often diagnosed by PCR or serology
Atypical organisms can be amplified by indirect immunofluorescence using DNA from a blood sample
Atypical organisms often present with a centripetal maculopapular rash which begins peripherally on the ankles and wrists and progresses to the trunk
Atypical organisms sometimes present with petechial rashes
Doxycycline and macrolides are effective treatments for atypical organisms