II-A. Systemic Bacteriology | 25. Rickettsia Flashcards
I. Rickettsia genus
1. What are the main features of Rickettsia genus?
- Intracellular, Gram-negative coccobacilli
- Could be categorised based on clinical diseases
- typhus group
- spotted fever group
I. Rickettsia genus
2. Give the classification based on clinical diseases?
I. Rickettsia genus
3. What are the species of typhus group?
- R. prowazekii ➡ (epidemic) typhus
- R. typhi ➡ endemic typhus
I. Rickettsia genus
4. What are the species of spotted fever group?
- R. rickettsii
- R. conorii
II. Rickettsia prowazekii
1. What is the source of infection of Rickettsia prowazekii?
infected person
II. Rickettsia prowazekii
2. What is route of transmission of Rickettsia prowazekii?
by the bite of body louse (Pediculus humanus)
II. Rickettsia prowazekii
3. What are the 2 diseases caused by Rickettsia prowazekii?
- epidemic (exanthematic) typhus
- Brill-Zinsser disease: reactivation
II. Rickettsia prowazekii
4. What are the features of epidemic (exanthematic) typhus?
- high fever, headache
- rash (present on palms, soles, and face as well!)
- confusion
- mortality is high (c.a. 40%) in untreated cases!
II. Rickettsia prowazekii
5. What are the features of Brill-Zinsser disease?
Brill-Zinsser disease: reactivation
* usually milder than the primary disease
* infectious!
II. Rickettsia prowazekii
5. What are the features of Brill-Zinsser disease?
Brill-Zinsser disease: reactivation
* usually milder than the primary disease
* infectious!
III. Rickettsia typhi
1. What is the source of infection of Rickettsia typhi?
Rodents (rats – zoonotic!)
III. Rickettsia typhi
2. What is the route of transmission of Rickettsia typhi?
through the bite of rat flee (vector- borne!)
III. Rickettsia typhi
3. What is the disease caused by Rickettsia typhi?
- high fever, headache
- rashes (palms - soles - face are usually spared!)
- disturbed state of consciousness
IV. Rickettsia rickettsii
1. Wha is the source of infection of Rickettsia rickettsii?
wild animals (zoonotic)
IV. Rickettsia rickettsii
2. What is the route of transmission of Rickettsia rickettsii?
by the bite of ticks (Dermacentor species)
IV. Rickettsia rickettsii
3. What is the pathomechanism of Rickettsia rickettsii?
- infects capillary endothelial cells, spread from cell to cell
- causes vasculitis (inflammation of vessels) in different organs
IV. Rickettsia rickettsii
4. What is the disease caused by Rickettsia rickettsii?
Rocky-mountain spotted fever (RMSF)
- flu-like symptoms after a week of incubation
- rash usually starts on the wrists, ankles then spread to other parts of
the body (face is usually spared!)
- mortality is high (20%) if left untreated!
V. Rickettsia conorii
1. What is the source of infection of Rickettsia conorii?
wild animals (zoonotic)
V. Rickettsia conorii
2. What is the route of transmission of Rickettsia conorii?
by the bite of ticks
V. Rickettsia conorii
3. What is the pathomechanism of Rickettsia conorii?
- infects capillary endothelial cells, spread from cell to cell
- causes vasculitis (inflammation of vessels) in different organs
(similar to RMSF)
V. Rickettsia conorii
3. What is the pathomechanism of Rickettsia conorii?
V. Rickettsia conorii
4. What is the disease caused by Rickettsia conorii?
mediterranean spotted ever
* similary to RMSF
* rash is usually present on the face as well
VI. Diagnosis of Rickettsia and Orientia infections
1. What is the diagnosis of Rickettsia and Orientia infections?
VI. Diagnosis of Rickettsia and Orientia infections
2. How do we do laboratory for Diagnosis of Rickettsia and Orientia infections
serology (it takes time for antibodies to be produced!)
1. immunofluorescence (IF): detection of anti-Rickettsia (anti-Orientia) antibodies from patient’s serum
2. Weil-Felix tube agglutination: etection of anti-Rickettsia antibodies from patient’s serum