Emerging Filo and Paramyxoviruses Flashcards
What are similarities between Marburg and Ebola viruses
both viruses are members of the virus family Filoviridae
named based on where outbreaks occur
What are differences between Marburg and Ebola viruses
genomes look similar but are antigentically distinct
When and where was the largest outbreak of Marburg virus
largest outbreak was in Angola in 2004-2005
88% mortality rate, combined of all cases is 82%
most infections occur in people who have recently visited caves in Uganda
When was the Marburg virus discovered
discovered in 1967 in Marburg germany
laboratory personnel contracted the virus while processing organs from African green monkeys imported from Uganda
When did the Ebola virus first appear
first appeared in 1976 in the democratic republic of Congo that is in central africa
When and where was the largest Ebola outbreak, what was the average morality rate for this virus
largest outbreak occurred in west africa during 2014-2016
average mortality rate is 42%
very lethal to the chimps and monkeys in the jungles of Africa
there is a current outbreak
How is the Ebola virus transmitted
animal to humans and human to human
How is Ebola transmitted from animal to human
eating of bushmeat: dead monkeys in the jungle
pteropodidae fruit bats are the reservoir host
transmitted by contacting fluids of wild animals or bats
How is ebola transmitted from humans to humans
direct contact with bodily fluids
sharing of food, kissing, intercourse, sexual contact
virus can live in semen for up to 82 days
contaminated surfaces
breast feeding —- vertical transmission
ebola virus can
persist after symptoms are resolved
Describe the pathogenesis of Ebola in general terms
Viral Hemorrhagic Fever
1 week incubation period
high level of viremia that is spread via the circulatory system
virus levels remain high throughout the infection
broken or ruptured blood vessels
loss of endothelial cells and breakdown of vascular structure
can be due to the direct infection or cytokine storm
destruction of lymphoid tissues, limited immune response
liver damage, kidney failure, gastrointestinal bleeding
severe infection leads to death in second week of illness, those that survive have a long recovery
day 7-9: headache, fatigue, fever, muscle soreness
day 10: sudden high fever, vomiting, blood, passive behavior
day 11: busing, brain damage, bleeding from mouth, nose, eyes, anus
day 12: loss of consciousness, seizures, massive internal bleeding, death
What types of cells are targeted by Filoviruses
can infect a large number of cell types
endothelial cells: line the blood vessels
immune cells: tissue macrophages
epithelial cells: can get inside of the tissues
Why are Filoviruses so deadly
can infect a large number of cell types
target tissue macrophages leading to tissue factor disregulation
induce prominent cytokine storm early in infection
very good at blocking the host antiviral defenses such as the interferon response
interferon makes interferon stimulated genes
VP35 blocks production in both Marburg and Ebola
VP40 blocks effects of interferon in Marburg
VP24 blocks effects of interferon in Ebola
Why does Ebola viruses disproportionately affect healthcare workers
Ebola disproportionally affects healthcare workers
the number of healthcare workers in affected countries was desperately low so they had to see many patients increasing the risk of exposure
What is ZMapp
convalescent plasma from a recovered patient
administration of neutralizing antibodies against Ebola Zaire glycoprotein: ZMapp
type of specific treatment for Ebola
is an experimental biopharmaceutical drug comprising of monoclonal antibodies as a treatment
viral polymerase inhibitor looks promising
What type of vaccine is used for Ebola
live attenuated vaccine
Describe the vaccine that has been developed for Ebola
Live- attenuated vaccine
only effective against Ebola Zaire virus
referred to as rVSV-ZEBOV
vaccine was developed by swapping the G envelope protein of vesicular stomatitis virus (VSV)
a Rhabdovirus with the Ebola GP envelope protein
shown to be effective in preventing infection by Zaire EBOV
5837 people vaccinated and no EBOV cases
23 cases in similar number of people in same locale and in same time frame that did not receive the vaccine
has been important tool in the outbreaks currently
the vaccine has to be specific for the strain circulating
What are treatments for Ebola
supportive care
fluid replacement, anti-diarrheal therapy, electrolyte replenishment, respiratory support, analgesics for pain, anti-epileptic medications, renal replacement therapy (dialysis)
specific treatments: ZMapp
What are emerging Paramyxovirues specifically the Henipaviruses
Hendra nad Nipah
When and where did Hendra virus originate and why type of animal is most associated with this disease
Hendra virus is a type of Paramyxoviruses
causes severe disease in horses
humans in close contact have been infected
first cases were discovered in racehorses in Queensland Australia in 1994
high morality rate in both intermediate hosts (hosts) and dead end hosts (humans)
think the reservoir host is bats
When and where did Nipah emerge
emerged in 1998 in Malaysia and Singapore
outbreak caused encephalitis in humans
link between pig workers and the disease so 1 million pigs were culled and this halted the spread of the virus
severe disease in pigs
resulted in huge economic loses due to the outbreak in 1998 there were more than 500 million dollars
think the reservoir host is bats
What is the likely reservoir host for Hendra and Nipah viruses
bats
originate the same family of bats like eobla
there may be a specific species that is more likely to carry it than other bat species
What is Henipavrius Pathogenesis
initial infection of lower respiratory tract followed by severe respiratory disease
damage leads to hemorrhage of the lung and release of virus into the circulatory system
once the virus is in the blood, it targets the organs including the brain
either compromises the blood brain barrier or travels along the olfactory bulb to gain entrance into the brain
causes severe encephalitis
What are the intermediate hosts in Hendra virus
horses and dead end hosts are humans
What are the intermediate hosts in the Nipah virus
pigs and dead end hosts are humans
What virus is in horses and humans and originated in bats that causes severe disease and what viral family does it belong to
paramyxoviruses
Henipaviruses
Hendra
What virus is in pigs and humans and causes encephalitis and originated in bats and what viral family does it belong to
paramyxoviruses
Henipaviruses
Nipah
What virus causes viral hemorrhagic fever and was the biggest outbreak was in 2014-2015 in west Africa and what viral family does it belong to
ebola and belongs to the filoviruses family
What virus had its largest outbreak in Angola from 2004-2005 and what viral family does it belong to
marburg and belongs to the filovirus family
Are filoviruses + RNA or - RNA
- strand
viral hemorrhagic fevers
Ebola
Marburg
Are paramyxoviruses + RNA or - RNA
- strand
