Rickettsia, Orientia Flashcards
How to classify?
Small obligate intracellular gram negative rods in endothelial cells
Can it be shown on gram stain?
No, stains poorly
What vectors?
Arthropod
Usually zoonoses (rodents, small mammals)
What does Orientia tstsugamushi cause? What is the vector and where in the world?
Scrub typhus
Mite, rodents
South East Asia
What are the 3 Rickettsia species?
R.prowazekii, R.typhi, R.rickettsii
Clinical presentations of Scrub typhus
Eschar and rash
Clinical features of Rickettsia
- Fever
- Headache
- Rash (macular, papular, petechiae/larger hemorrhagic lesions, vesicular, some cause eschar)
- SIRS (can be severe and fatal)
- Meningoencephalitis (with dizziness, confusion and even coma)
What does typhus lead to?
Vasculitis, perivasculitis
-Infection leads to destruction of endothelial cells
Eschar, rash
What does R.prowazekii cause?
Epidemic typhus
Causes myalgia, arthlagia, pneumonia, encephalitis with dizziness and confusion
What is the reservoir and vector of R.prowazekii?
Man
Spread by louse vector (infection kills louse vector)
How to prevent R.prowazekii?
Delouse susceptible populations (poverty, overcrowding)
What is Brill-Zinsser disease?
When R.prowazekii infection reactivate in human patient after many years
Risk factors to R.prowazekii epidemic typhus?
Overcrowding, poor hygiene, social upheaval, war
What can R.prowazekii epidemic typhus present with on skin?
Petechiae rash, gangrene of extremities
What does R.rickettsii cause?
Rocky mountain spotted fever
