pathogenic viruses Flashcards
non segmented negative strand RNA viruses
Paramyxoviridiae
Rhaboviridae
Filovirdiae
paramoxyviridea pathogens
respiratory measles and mumps
paramoxyvirdia structure
Viral RNA HN/H/G (Hemagluttin -neuraminidase F (fusion protein) L (RNA polymerase) N (nucleocapsid)
measles virus
acute childhood disease most contagious high mortalitiy in developing countries 1 serotype cold like symptoms and Koplik spots that turn to rash conjunctuvitis (pink eye) MMR vaccine
mumps virus
1 serotype
swollen salivary glands and fever
MMR vacine
rhaboviridiae
rabies -acute fatal viral inflammation of brain
enveloped virus
bullet shape
death by respiratory paralysis
virus can stay in the muscle for months or years before reaching peripheral nerves and going systemic
once symptoms occur there is no cure and 100 percent fatality
before symptoms you can get the vaccine and passive immunoglobin
rabies diagnosis
easier to detect after death in brain b/c negri bodies seen in Purkinje cells
direct flourescent antibody test
before death several test are needed to diagnose
filoviridiae
ebola virus -filamentous virion
ebola virus
4 subtypes and 3 of them cause human disease
resovoir most likely bats
what does flu vs a cold affect?
flu affects both upper and respiratory tract
cold affects only upper respiratory tract
children vs adults in influenza
children shed virus for weeks vs days for adults
who are at high risk of influenza?
children especially >1 yr
elderly
adults with underlying health problems
pregnant women
complications of influenza?
pneumonia
excaberate chronic health problems
properties of influenza?
enveloped virion
genome is segmented, negative, single stranded RNA
receptor is saliac acid
H hemagglutinin binds to receptor
what is necessary for influenza infection?
binding of saliac acid with viral H needed to bind and infect
after budding viral enveloped contains both H and sialic acid
neurominidase
cleaves sialic acid to aid in viron release
mucous contains a lot of sialic acid to bind and trap to the virus but neurominidase prevents this trap.
influenza virulence factors
H - hemagluttinin binds receptor
N - neurominidase cleaves sialic acid
M2 - ion channel allows uncoating by decreasing pH of virion
antigenic shift vs drift
antigenic shift = abrupt changes by reassortment (segmented virus)
antigenic drift = gradual changes by mutation and error prone polymerase. mutation in antibody binding sites on H
H hemagluttinin
evolves rapidly
16 H subtypes
mixed infection is caused by?
antigenic shift
cause pandemics
retroviridiae
rna/dna virus
reverse transcription
integration part of life cycle
high evolution rate
lentivirus
HIV
cause chronic progressive disease
replicate in nondividing cells and kill cells
envelope virus
HIV virion structure
genome: 2 identical copies of RNA strand non segmented
3 enzymes in caspid are; reverse transcriptase, integrase, protease
what does hiv deplete?
HIV depletes CD4 + T cells