Rickettsia rickettsii

Definition

Rickettsia rickettsii is a gram-negative, intracellular bacterium that causes Rocky Mountain Spotted Fever (RMSF). It primarily infects endothelial cells lining the blood vessels leading to widespread vasculitis.

5 Must Know Facts For Your Next Test

1. Rickettsia rickettsii is transmitted to humans through the bite of infected ticks, particularly Dermacentor species.
2. Symptoms of RMSF include fever, headache, rash, and in severe cases, can lead to multi-organ failure.
3. The bacterium replicates within the host’s endothelial cells causing damage and increased vascular permeability.
4. Diagnosis often relies on clinical presentation and serological testing since cultures are difficult to perform.
5. Treatment typically involves prompt administration of doxycycline even before confirmatory tests are completed.

Review Questions

• What is the primary mode of transmission for Rickettsia rickettsii?
• Which cells does Rickettsia rickettsii primarily infect in the human body?
• What is the first-line treatment for Rocky Mountain Spotted Fever caused by Rickettsia rickettsii?

Related terms

Rocky Mountain Spotted Fever (RMSF): A potentially lethal disease caused by Rickettsia rickettsii characterized by fever, rash, and vasculitis.

Dermacentor: A genus of ticks known to be vectors for transmitting Rickettsia rickettsii.

Doxycycline:

An antibiotic commonly used as the first-line treatment for infections caused by Rickettsia rickettsii.