DD- Virology of Ebola Flashcards
Ebola
rare and deadly disease caused by infection with a strain of Ebola virus.
Ebola causes
Hemorrhage from DIC
Filoviruses
encode their genome in the form of single-stranded negative-sense RNA.
2 members are Ebola virus and Marburg virus.
20% of people with ebola in recent outbreak are
health care workers
Ebola usually comes from
epizootic cycle
Ebola often is caused by ____ (animal)
fruit bat
which can spread to other animals/humans
Ebola outbreaks result from spillover events from animal reservoirs with subsequent ____________ transmission
human-to-human
Ebola Structure
Enveloped, negative-strand RNA, replicates in the cytoplasm
Ebola Enters body through:
mucosal surfaces or cuts to the skin
Ebola initially enters phagocytic cells, sends signal for more cells to come, which facilitates infecting those cells; also spreads efficiently when cells go to lymph nodes, which allows ebola to infect more _________
immune cells
After someone is infected with ebola, it is believed that he/she is________from future
infections; antibodies found out to 10 years after infection
protected
Antibody response to the surface glycoprotein on ebola is associated with ____
better survival
Ebola initially enters phagocytic cells, sends signal for more cells to come, which facilitates infecting those cells; also spreads efficiently when cells go to _______, which allows ebola to infect more immune cells
lymph nodes
Ebola has many ways to evade the human immune system
Glycoprotein (surface)
Glycoprotein (secreted)
VP35 and VP24
EBOLA:
Masks antibody binding sites/ highly variable/dispensible
Physically blocks the MHC and other cell surface proteins in order to block their role in triggering an immune response
Glycoprotein (surface)
Ebola initially enters ________, sends signal for more cells to come, which facilitates infecting those cells; also spreads efficiently when cells go to lymph nodes, which allows ebola to infect more immune cells
phagocytic cells
EBOLA:
secreted by the cell, act as decoys; antibodies against ______ aren’t very good at neutralizing the virus
Glycoprotein (secreted)
EBOLA:
both interfere with the cell’s interferon production, which plays a role in signaling for “help” and also inhibits the cell from apoptosis
VP35 and VP24
Initial cytokine release signaling for more immune cells to come to the area of initial infection, helps:______
ebola to spread
______ is the genetic material for Ebola
RNA
Found on viral envelope (also a secreted form)
Function: attachment and entry, key for pathogenicity
Glycoprotein = GP
Main part of virion/matrix, plays a role in virus structure, stability, assembly and budding
VP40:
Assembly, budding, nucleocapsid assembly, immune defense
VP24
Form the nucleocapsid (capsule around the genetic material/nucleus)
Nucleocapsid and nucleoprotein = VP30 and nucleoproteins
Ebola spead/infection
Only need a few virions for infection
Travels in immune cells (white cells) to regional lymph nodes where it replicates and spreads throughout the body
In the cell, ebola induces a massive:
“cytokine storm”
These molecules destroy vessel walls, also induce disseminated intravascular coagulation (DIC) - shock
Causes a dysregulated immune response
Get leakage of fluids and blood leading to severe fluid losses and possibly bleeding
Hypovolemic shock
Organ failure due to hypovolemia and/or direct destruction from virus
Effects of Ebola in vessel cell walls
People Die from ebola with________ +/- end-organ failure
hypovolemia
(Don’t die from hemorrhage)
Patients can lose 5-10 liters of fluid/day through “effluent” (vomit, diarrhea)
hypovolemia
state of decreased blood volume
These molecules destroy vessel walls, also induce disseminated intravascular coagulation (DIC) - shock
Causes a dysregulated immune response
“cytokine storm”
Effects of Ebola in vessel wall
Get leakage of fluids and blood leading to severe fluid losses and possibly bleeding
Hypovolemic shock
Organ failure due to hypovolemia and/or direct destruction from virus
Interfere with a cell’s signaling pathway that alerts immune cells that it’s infected
VP35 and VP24
EBOLA Incubation is _______days after exposure, but usually 6-10 days
– NOT contagious until symptomatic
2-21
monoclonal antibodies against 3 targets on GP
Zmapp
Drugs for Ebola
targets DNA viruses, nucleotide analogue, found to have in vitro efficacy against Ebola; a few of those treated in the US received it
Brincidovovir
Drugs being studied for ebola
under development in Japan for influenza, nucleotide analogue for RNA
Favipiravir
Drugs being studied for ebola
Ebola Rx
Management is symptomatic by
o Fluid repletion o Electrolyte corrections o Renal replacement, ventilation o Need critical care o Need to isolate patients
Symptoms of Ebola
GI, fever, fatigue/weakness; very similar to
other illness which are common (malaria, typhoid, dysentery)
After initial Ebola infection of phagocytes, then goes to infect many other cells/organs
in the body including:
endothelial cells
liver
spleen
lungs
EBOLA: Once in the cell, induces a massive cytokine storm –
cytokines and similar
molecules destory vascular endothelium, induce _________
disseminated intravascular coaculation (DIC)
