VHF Flashcards
What is Viral Hemorrhagic Fever?
group of illnesses caused by several distinct families of viruses that effect H and non-H primates
VHF affects
overall vascular system
dysregulation, increased permeability and damage
Symptoms of VHF
severe multisystem syndrome
symptoms often accompanied by hemorrhage (rare life threatening itself, includes conjunctivitis, petechial, ecchymosis)
Poor myocardinal contractility with low cardiac output and high peripheral resistance
Four distinct families of viruses
arena-viruses
filo-viruses
bunya-viruses
flavi-viruses
RNA viruses
enveloped in lipid coating
Survival of viruses
dependent on an animal or insect host for the natural reservoir.
If host dies, viruses dies too
arenaviridae
rodents;
junin, machupo, sbia, guanarito, lassa
bunyaviridae
Crimean-congo
hantavirus
rift valley fever
filoviridae
bats;
ebola
marburg
flaviviridae
kyasanur forest disease
Omsk H.F.
Yellow Fever
Dengue
tick
major problem especially in eastern Asia and Africa.
filoviridae history
1967 Marburg virus (laboratory workers in Europe)
1976 Ebola virus
Ebola virus
Filovirus: enveloped non-segmented, negative stranded RNA virus
Ebola fatality and treatment
severe disease with high case fatality
and absence of specific treatment or vaccine
2014 Ebola
West Africa Ebola outbreak caused by Zaire ebolavirus species
Ebola Virus 유래
zoonotic virus: bats most likely reservoir, but species unknown
- Spillover event from infected wild animals such as fruit bats, monkey, duiker to humans
- followed by human to human transmission
Ebola virus is present in..
virus present in high quantity in blood, body fluids and excreta of symptomatic infected patients
Ebola human to human transmission
direct contact (through broken skin or unprotected mucous membranes)
sharp injury (with contaminated sharps)
direct contact with the corpse of a person who died of EVD
Indirect contact with an infected patient’s blood or body fluids via contaminated object
Ebola can be transmitted via blood, fluids or meat of an infected animal
Ebola human to human transmission 2
infected persons are not contagious until onset of symptom
infectiousness body fluids (viral load) increases as patient becomes more ill
Remains from deceased infected persons are highly infectious
Aerosol transmission of Ebola
transmission of Ebola virus via aerosols has NOT been demonstrated
Ebola Virus Pathogenesis
Direct infection of tissues
Immune dysregulation
Hypovolemia and vascular collapse (electrolyte abnormalities, multi-organ failure and septic shock)
disseminated intravascular coagulation and coagulopathy
Clinical Features of Ebola
nonspecific early symptoms but
- hypovolemic shock, multi-organ failure
- hemorrhagic disease
- death
Fatality of Ebola
Fatal disease associated with more severe early symptoms
Fatality of 70% historically reported in rural Africa
Ebola Survival rate
Intensive care, especially early intravenous and electrolyte management, may increase the survival rate
clinical management of EVD:
Hypovolemia and sepsis physiology
aggressive intravenous fluid resuscitation
hemodynamic support and critical care management if needed
clinical management of EVD:
Electrolyte and acid-base abnormalities
aggressive electrolyte repletion
correction of acid-base derangement
clinical management of EVD:
Symptomatic management of fever & GI symptoms
avoid NSAIDS
clinical management of EVD:
Multisystem organ failure can develop and may require…
oxygenation and mechanical ventilation
correction of severe coagulopathy
renal replacement therapy
