REVIEW: RMSF Flashcards
Know the following characteristics about each bacterial disease studied for this unit:
a. Genus and species name (English equivalent if given)
b. Gram reaction
c. Cell shape
d. Disease name
e. Virulence factors
f. Transmission
g. Clinical symptoms of disease
h. Vaccine available
i. Treatment
a. Genus and species name (English equivalent if given): Genus - Rickettsia species: rickettsiae
b. Gram reaction: Gram –
c. Cell shape: Bacillus
d. Disease name: Rocky Mountain spotted fever (RMSF)
e. Virulence factors: Bacteria enter capillaries when tick takes blood meal
Infect endothelial cells (lining) of blood vessels and destroys cells
Hemorrhaging, tissue death and blood clots initiated
Endotoxin causes more bleeding from blood vessels and along with blood clotting results in: Disseminated Intravascular Coagulation
f. Transmission: tick vector
wood tick, dog tick
g. Clinical symptoms of disease: Head-ache, muscle/joint-ache
Fever – 1040F
Maculopapular Rash: pink, raised spots start on extremities then moves on to torso
Maculopapular rash: hemmorhagic reaction (blood leaking into the tissue is evidence of vascular damage)
Late lesions can become gangrenous
h. Vaccine available: No longer available
Was Reserved for individuals at high risk (lab workers, veterinarians) but vaccine has been pulled off market
i. Treatment: Tetracycline
Immunity appears to be permanent after recovery
- Who discovered the bacteria that causes RMSF?
Howard Ricketts
- What is an obligate intracellular parasite?
Obligate Intracellular Parasite:
cannot be grown on artificial media
requires animal tissue cells
- What is the size of the Rickettsia bacteria and can the bacteria be seen with a compound microscope?
0.5 um- can be viewed by compound microscope
- How is the tick affected by Rocky Mountain spotted fever (RMSF)?
Tick is not harmed by the disease
- What two ways can the tick become infected with Rickettsia rickettsiae bacteria?
Becomes infected two ways:
feeding on infected animal
transovarian transmission
- What is transovarian transmission of bacteria in ticks?
Means Infected Female Tick = Infected Tick eggs= Infected tick
- Where is the tick belt in the United States?
Eastern United States
PA, GA, NY, VA, KY, TN, NC, SC
- What is disseminated intravascular coagulation?
Small blood clots form in blood vessels because of damage
Slows or stops blood flow and can shut down internal organs
Exhausted clotting proteins can lead to hemorrhaging
- What are the characteristics of a maculopapular rash? Where does it start in RMSF?
Maculopapular rash: hemmorhagic reaction (blood leaking into the tissue is evidence of vascular damage)
Late lesions can become gangrenous
It starts on hands/feet and moves inwards towards center of body
- What immunity if any is generated after recovery of RMSF?
Immunity seems to be permanent after recovery. (And if you get it treated, your chances of recovery are pretty good.)
- Is there a current vaccine available for RMSF?
No longer available
Was Reserved for individuals at high risk (lab workers, veterinarians) but vaccine has been pulled off market
- What is the Weil-felix test and what disease does it diagnose?
Used to diagnose any Rickettsial disease
Patients blood serum + Proteus OX19 (strain #) agglutination(+); no agglutination (-)
Proteus OX19 has Ags in cell wall similar to Rickettsia
- What is a preventative therapy to prevent disease transmission from tick to human?
Remove the tick before it’s been on you for 4 hours.
- Why is blood serum and not whole blood used for the Weil-Felix test?
This test screens for Abs to Rickettsia
Ab molecules are found in blood serum
If Abs to Rickettsia are present, they will be in patients blood serum
