Rickettsial and Related organisms

Question 1

general features of Rickettsia

Answer 1

are obligate intracellular bacteria, are gram negative, they are usually transmitted by arthropods like ticks, mites, or louse

Question 2

what cells do Rickettsia invade

Answer 2

invade endothelial cells and can cause infections that disseminate in the blood to many organs

Question 3

what are the 2 main groups of Rickettsia

Answer 3

the spotted fever group and the typhus group

Question 4

how does the Rickettsia metabolism work

Answer 4

these are obligae intracelluar energy parasites, they will enter the cytoplasm of the host cell, and will exchange ADP for ATP in the mitochondria, as well as acquiring amino acids

Question 5

transmission of a Rickettsial infection includes

Answer 5

1. attachment to the endothelial cells, resulting in phagocytosis , escape from phago-lysosomes to multiply in the cytoplasm 2. extravascular leakage of blood 3. decreased blood volume and decreased perfusion of organs 4. leads to damage to organs

Question 6

what does the resulting damage look like?

Answer 6

vascular damage —— Edema ——Cutaneous Necrosis

Question 7

Rocky Mountain Spotted Fever clinically presents as

Answer 7

headache, fever, malaise, vomiting, and a characteristic rash at the site of tick attachment, 1 week incubation period

Question 8

how does the RMSF rash present

Answer 8

it starts on the palms of the hands, and feet and spreads upwards. - it is a macu-papular rash of defined lesions that spreads upward and resembles measles. `

Question 9

Rickettsialpox disease

Answer 9

due to R. akari, transmitted by a mite, not a tick, through the mice which acts as a vector. A hard nodule forms where the bite occurred

Question 10

Epidemic typhus and what disease does it cause when re-infection occurs?

Answer 10

due to R. prowazekii, spread by lice only on humans, can cause Brill-Zinsser disease

Question 11

how is the disease epidemic typhus transmitted

Answer 11

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