Rickettsiae and other pathogens that target endothelial cells Flashcards
What are some of the pathogens that act on endothelial cells?
Rickettsia, CMV, HHV8
What bacteria are found within the rickettsiae family?
- Anaplasma phagocytophilum
- Ehrlichia cafeenis
- Rickettsia prowasekii
- Rickettsia rickettsii
- Rickettsia typhi
Rickettsiae are __ (extra/intra)cellular pathogens and are gram __
obligate intracellular; negative
Rickettsia rickettsii are caused by __. They then cause __.
Ticks; Rocky mountain spotted fever
What shape are ricfkettsia rickettsii?
Small (0.3 x 1micron) coccobacilli
Are rickettsia rickettsii able to produce their own energy?
No, they utilize host carbon sources and host ATP
Where do rickettsia rickettsii divide?
In the cytoplasm of infected cells
Rickettsia uses what protein to transfer from cell to cell? How do they spread?
Utilize host actin, they can spread without encountering extracellular environment
What is the main target of R. rickettsii?
Vascular endothelial cells
What are components of the pathophysiology of R. RIckettsii?
- Alters and damages endothelial cells
- Platelets bind to altered endothelial cells and set up cascade of events that lead to DIC
- Endothelial damage leads to blood leakage out of blood vessels, which in turn leads to shock
What are the symptoms of R. Rickettsii?
Prodromal symptoms occur within 1-2 weeks
- Chils, fever, rash, headache, RASH (90% of cases. Rash is erythematous, maculopapular, petechial). Typically on extremities, then travels to trunk
- Fulminant vasculitis, especially of endothelial cells as well as the vascular smooth muscle cells of kidney, heart, skin, brain, and subq tissues.
- Vascular endothelial damage is proportional to number of rickettsiae parasitizing them
Is RMSF fatal?
Yes, case fatality is 25% without treatment
What is the firstline treatment for RMSF?
Doxycycline (targets 30S subunit). Treatment within 5 days is highly effective. Doxycycline does not cause staining of permanet teeth
Hantavirus is transmitted from?
Inhaled aerosols contaminated with rodent feces or urine (not person to person)
What type of virus is hantavirus and what family is it in?
Enveloped RNA virus in Bunyavirus family. Has segmented genome
Is seroprevalence high or low typically for hantavirus? What might this mean?
Seroprevalence is low, which means that people have not really made antibodies for this virus
What is a robovirus?
transmitted directly from infected animals without arthropod vector
Where is hantavirus usually found?
Southwest of the US. New Mexica, Arizona, California, Colorado.
Outbreaks for hantavirus have been found to occur with __.
El Nino
What is included with hantavirus pathogenesis?
- Affects cardiac, renal, and pulmonary systems
- Viral replication in capillary endothelial cells increases vascular permeability
- Symptoms are caused by direct viral effects on endothelium and immunopathology caused by innate and adaptive responses to viruses
Human herpes viruses are what type of virus?
Enveloped, ds DNA viruses
What are some examples of human herpes viruses?
- HSV1 & HSV2
- VZV (primary-chicken pox, secondary=shingles)
- EBV: mono, B-cell lymphomas
- CMV
- HHV 6/7: Roseola
HHV8: Kaposi sarcoma
EBV causes?
monospot/heterophile aby+
CMV causes
mono (monospot -)
CMV infects which types of cells?
myeloid, smooth muscle, and endothelial cells (OWL EYE INCLUSIONS)
Is HHV-8 a typical or an atypical virus?
Atypical. It is not widespread in the general population. Most commonly in sub-saharan african, middle east, and moderate prevalence in mediterranean and lower in the US
- Reasons for geographic distributions not understood
- First detected in Kaposi’s sarcoma, an endothelial neoplasm
- Also associated with B-cell lymphoproliferative diseases
- Viral infection of endothelial cells causes VEGF production and angiogenesis
