Gain a solid understanding of Rickettsia's biology, including its unique morphology, life cycle, and growth requirements.
Learn how Rickettsia interacts with host cells, the mechanisms of pathogenesis, and the clinical manifestations of Rickettsial infections.
The Rickettsiae are a diverse collection of obligately intracellular Gram-negative bacteria found in
ticks, lice, fleas, mites, chiggers, and mammals. They include the genera Rickettsiae, Ehrlichia,
Orientia, and Coxiella. These zoonotic pathogens cause infections that disseminate in the blood to
many organs.
General Features of Rickettsiae:
• Obligate intracellular pathogens
• Extremely small coccoids or rods (0.3 x 1 to 2micrometre)
• Has no flagella
• Cannot grow on microbiological media, some grow in embryonated eggs or in tissue culture
cells
• Structurally similar to gram negative cells (LPS & peptidoglycan cell walls)
• Multiply by binary fission but only in infected cells
• With the exception of Coxiella all transmitted by arthropod vectors (e.g. ticks, mites, lice,
fleas)
Diseases caused by Rickettsiae
Disease Agent Arthropod Vector
Rocky Mountain spotted fever Rickettsia rickettsii Wood tick
Rickettsial pox Rickettsia akari House mouse mites
Murine typhus Rickettsia typhii Rat flea
Epidemic typhus Rickettsia prowazekii Human body louse
Scrub typhus Orientia tsutsugamushi Chigger mites (mite larva)
Ehrlichiosis Ehrlichia chaffeenis Lone star tick
Q fever Coxiella burnetti None-spread by inhalation
Typhus
○ Caused by Rickettsia prowazekii
○ Arrived in Europe in 1489 via soldiers returning from Cyprus.
○ In 1557-1559 an outbreak in England killed 10% of the population
○ Transmitted by Pediculus humanus corporis (contamination with infected faeces during
feeding)
○ Incubation 7-14 days, high fever 40 degrees Celsius, chills, headache, may lead to coma.
○ Macular eruption (skin disease) 5-6 days after onset.
REMEMBER THE DIFFERENCE: TYPHUS VS TYPHOID (caused by two different bacteria)
Typhus: Cough, headache, joint and muscle pain, nausea, chills, confusion, low blood pressure
(Rickettsia typhi, prowazekii)
Rickettsia Page 1
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Lakuscholars. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £7.16. You're not tied to anything after your purchase.
