4 Rocky Mountain Spotted Fever

Question 1

How does Rickettsia rickettsii enter and survive in the host?

Answer 1

Enters via tick bite, proliferates inside endothelial cells using binary fission, spreads cell-to-cell.

Question 2

What is the role of endothelial cell invasion in disease progression?

Answer 2

Infection of endothelium causes injury, leading to edema, hypovolemia, hypotension, hypoalbuminemia, and microvascular damage.

Question 3

How does R. rickettsii evade immune responses?

Answer 3

By living and replicating inside host cells, particularly endothelial cells.

Question 4

What is the mechanism behind systemic vasculitis in RMSF?

Answer 4

Vascular injury due to intracellular infection → fluid leakage and impaired organ perfusion.

Question 5

What does “Rocky Mountain Spotted Fever” refer to?

Answer 5

A life-threatening tick-borne illness caused by Rickettsia rickettsii.

Question 6

What is the proper naming of Rickettsia rickettsii?

Answer 6

Genus: Rickettsia, Species: rickettsii (italicized, lowercase species).

Question 7

Why is it described as a “spotted fever” group rickettsiosis?

Answer 7

Characteristic rash (maculopapular → petechial) develops; historical name: “black measles”.

Question 8

How can key features like transmission route, symptoms, and prognosis be summarised from case studies?

Answer 8

Transmitted via tick bite; incubation ~7 days; early signs include fever, headache, rash; untreated fatality ~20%, treated ~5%.

Question 9

What clinical signs are most diagnostic in early disease stages?

Answer 9

Sudden high fever, severe headache, malaise, myalgia; rash appears 2–5 days after fever.

Question 10

How can public health prevention strategies be inferred from transmission data?

Answer 10

Tick checks and avoiding tick exposure (especially in tick season: April–Sept) are essential preventive measures.