Ebola hemorrhagic Flashcards
Ebola hemorrhagic
First discovered in ebola river, Republic of Congo
2014 Africa outbreak
Ebola Virus (5)
Virus family: Filoviridae (thread like appearance)
Large outbreaks
Bundibugyo ebolavirus
Sudan ebolavirus
Zaire ebolavirus
Tai
Reston
Ebola transmission
- origin unknown but fruit bats are likely hosts, (Pteropodidae)
- spread through feces, get on fruits n food etc
- 2014 mostly due to human transmission
- direct contact through broken skin or infected surfaces
- bodily fluids contact
-sexual transmission
maternal transmission
-not contagious during incubation
-symptoms occur 2-21 days usually 8-10
1st stage
7-9 days
- flu symptoms
- muscle soreness
2nd stage
10th day
- vomiting blood
- extreme fatigue
- diarrhea
3rd stage
11th day
- brain damage
- bleeding from anus, nose, mouth
4th stage
12th day
- coma
- organ failure
- internal bleeding
- death
Diagnosis
- low WBCS due to infected DC cells, less t and b cell activation
- abnormalities in blood clotting
macrophages ingest virus and release inflammatory signals that causes blood cells to leak - elevated liver enzyme levels
liver cells are destroyed
4 scientific methods to confirm diagnosis
- isolate blood and look at cell culture and WBC count
- PCR to detect RNA strains and see if sequence matches
- detect proteins (ELISA)
- detect antibodies
ebola virus structure
- single linear ssRNA genome
- whole length of virus is 80nm vs 800nm
- center helical ssRNA wrapped about nucleoproteins VP 30 and 35 that help organize genome
- glycoproteins wrap around whole virus and help it anchor themselves to cells
- other viral proteins which are what macrophages and DC cells mainly detect
- Envelope gp proteins
GP1: helps anchor
GP2: drives membrane fusion
immune system invasion experiment
Method:
- infected 293 embryonic kidney cells with zaire virus
- in presence or absence of anti-glycoprotein mouse antibody
- use anti VP40 antibody to detect infected cells with immunofluoresence analysis
green: where virus infection occurs
results: enhanced virus in presence of anti GP (especially phagocytes)
- takes advantage of our bodies ability to recognize pathogens and antibodies
-
Phagocytosis process
Recognition: neutrophils like macrophages or DC cells recognize foreign particles on antigens
Engulfment: phagocyte extends its plasma membrane and engulfs cell/particle
Digestion: Fusion with lysosomes for digestion and destruction
- respiratory burst: sometimes occurs triggers, generates reactive oxygen species that damages pathogens
Complementary Proteins
proteins that recognize these particles
igG protein: bottom Y part (FC) binds to antibody receptor
- top (fab) portion binds to binds to epitopes
c3b proteins can also attach to antigens to phagocytes
5 step complement activation targets for phagocytosisor lysis
1) anitbody binds to bacterium
2) antibody coated bacterium binds to FC receptors on cell surface
3) macrophage membrane surrounds bacterium
4) membrane fuses, creates phagosome: membrane bounded vesicle
5) lysosome fuses with phagosome, creates phagolysosome
antibody dependent viral infection
- ebola virus binds to specific receptors on cell surface
- igG proteins bind to glycoprotein epitopes on virus
- FC region binds to cell component 1 (C1) proteins on cell surface
- This interaction stabilizes interaction between virus and cell surface, increases likelihood of viral attachment to target cells
