Rickettsial Diseases Flashcards
What are cellular characteristics of Rickettsia?
Gram-negative, Rod-to-coccoid-shaped bacterium. Similar to Chlamydia. Size of a large virus
How are Rickettsiae similar to both bacteria and viruses?
Obligate intracellular bacterial parasites. Cell wall resembles that of gram-negative rods. In arthropods (insects), rickettsiae grow in the gut lining. Human infection results from either an arthropod bite or contamination with its feces
What is the pathophysiology of Rickettsial disease?
has a tropism for endothelial cells that line blood vessels. Damage the endothelial lining of the vessel wall. Damage to the vessels of the skin results in rash. Most Rickettsia cause rashes, high fevers, and bad headaches.
What are the Rickettsial diseases in the US?
Rocky Mountain Spotted Fever, Rickettsial pox, Endemic Flea-Borne Typhus (Murine Typhus), Epidemic Louse-Borne Typhus
What is the pathogen, geography, insect vector and other carriers of epidemic (louse-borne typhus)?
Rickettsia prowazekii. Central/Northeastern Africa, Central/South America. Louse. Humans, flying squirrels are carriers
What is the pathogen, geography, insect vector and other carriers of endemic (murine) typhus?
Rickettsia typhi. US-southeastern gulf. flea. Rodents are carriers
What is the pathogen, geography, insect vector and other carriers of Rickettsial pox?
Rickettsia akari. US. Mite. Mice are carriers
What are treatment options for Rocky Mountain Spotted Fever?
Doxycycline for most patients. If pregnant treatment is chloramphenicol. Treat for at least 3 days after the fever subsides.
What is the clinical presentation of epidemic louse-borne typhus?
malaise, cough, HA, arthralgias. Abrupt onset of chills, high fever, and flu-like symptoms progressing to delirium and stupor. Causes pneumonia that ends up killing patients
What is Brill-Zinsser Disease?
R prowazekii can survive in lymphoid tissues after primary infection, and years later, produce disease. serve as a point source for future outbreaks. More gradual onset than primary, fever and rash are of shorter duration, and the disease is milder and rarely fatal
What are treatment options of epidemic louse-borne typhus?
doxycycline for most patients. if pregnant, chloramphenicol
How is endemic (Murine) typhus diagnosed and treated?
Labs, Dx, and Tx really the same as for Epidemic Louse-Borne Typhus. Doxy for most patients. Use cipro if pregnant
What is the treatment for Rickettsialpox?
keep calm and Doxycycline on
What is the epidemiology of Q fever?
Gram-negative intracellular organism Coxiella burnetti (formerly known as a rickettsia, but now considered a proteobacteria). Infects cattle ( usually spread in milking), sheep, and goats. Highly resistant spore stage that is transmitted to humans when animal tissue is aerosolized or ingestion of contaminated milk
What is the clinical presentation of Q fever?
sudden fever, severe headache, cough, and other flu-like symptoms. Hepatitis is frequent enough that the combination of pneumonia and hepatitis should suggest Q fever.
