Rickettsial Rashes

Question 1

Rickettsia rickettsia

Answer 1

Rickettsial Rashes
• Gr- coccobacillus
• *obligate intracellular parasites
• tropism for *vascular endothelium
• *primary pathologic lesion is a vasculitis
• reservoir dogs, rodents
• main vector: dog or wood tick (Dermacentor)
- causes *Rocky mountain spotted fever (most common rickettsial infx)
VIRULENCE
• *LPS
• *phospholipase A 
• *tremendous strain variation
• various OMP adhesions
• proteases
TX
- DOXY

Question 2

Rickettsia prowazekii

Answer 2

Rickettsial Rashes
• *obligate intracellular parasites
• tropism for *vascular endothelium
• *primary pathologic lesion is a vasculitis
• reservoir: *U.S. southern flying squirrel, humans
• vector: *human body louse
- causes *Epidemic Typhus (in Central America, South America, Africa)

Question 3

Rickettsia typhi

Answer 3

Rickettsial Rashes
• *obligate intracellular parasites
• tropism for *vascular endothelium
• *primary pathologic lesion is a vasculitis
• reservoir: *rodents
• vector: *flea
- causes *Endemic Typhus (Africa, Asia, Australia, Europe, South America)(mostly TX, CA)