.....the flu .......... Flashcards
influenza and ebola are caused by
Baltimore group V viruses
what type of RNA causes influenze and ebola
ssRNA
what else are caused by group V viruses
Measles, mumps, rubella, rare and lesser-known disease
influenza and ebola are env
ENVELOPED
influenza and ebola survival
do not survive long outside of a host and are spread only through fluids
genetic material of group V viruses
(-) ssRNA
ssRNA must be
turned into an antigenome of (+) mRNA to make proteins , happens in cytoplasm of host
after (-) ssRNA is turned into (+) mRNA
copied into more (-) RNA to make more viruses
3 forms of influenza
influenza A
influenza B
influenza C
influenza A
the scariest and most contagious form… since affects many species , mutates fastest
what species do influenza infect
humans, birds, pigs, seals , horses
influenza is further broken into
classes based on the presence of H and N antigens
influenza B
only transmitted by humans (and seals?)
influenza B mutations
2-3x slower than influenza A
influenza C
rarely causes human disease and is not considered a threat
influenza A strains have how many genes
just 11
two of the influenza A genes code for
important envelope proteins
one of the important influenza A genes
HA
HA
codes for hemagglutinin
how any HA pattenrs
18, (H1-H18)
Hemagglutinin is responsible for
attaching influenza virus to sialic acids
sialic acids
sugars found outside the membrane of many human cells
hemagglutinin promotes
viral attachment
almost all human flu strains have only the
H1, H2, or H3 antigen
H1, H2, H3 antigens attach to
2,3-linked sialic acid
2,3-linked sialic acid is
found outside the membrane of upper respiratory cells
thus……… because of the H1, H2, H3 antigen
the flu attaches to, and invades and infect cells in the upper respiratory tract
the H5 is
found in avian flu viruses
H5 antigen attaches to
2,6-linked sialic acid
2,6-linked sialic acid is found
outside the membrane of lower respiratory cells
deep tract influenza from H5
BAD…… bird flu… 50 PERCENT MORTALITY
what is the other influenza A gene that codes for an important envelope protein
NA
NA codes for
neuraminidase
how many known NA patterns
11 (N1-N11)
neuraminidase is responsible for
cleaving sialic acids off cell membranes, allowing the flu virus to detach
only which NA patterns are seen in the human flu
N1 and N2 , and rarely (N3, N7, N8)
before the flu virus detaches
it attaches initially w/ hemagglutinins on sialic acid
the flu exhibits both
genetic shift and genetic drift
genetic shift
combination of different flu types in one cell
in genetic shift the genetic material is
swapped around and a new superflu develops
what was an example of genetic shifting 2009
H1N1 swine flu outbreak of 2009
example of genetic shift
Avian H5N2 and swine H2N1 create dangerous H5N1
influenza pandemic of the 20th century
spanish flu, asian, hong kong…. all A
genetic drift
the slow mutation of one flu type….. usually just one amino acid at a time.
antibodies are super
specific
since human antibodies are extremely specific, so one small mutationn
can make antibodies ineffective
because of genetic drift you can catch the flu
many different times
how many total amino acids in HA
527
example of genetic drift
H1N1 mutates to have slightly different H structure many antibodies no longer recognize
because genetic drift you can get sick
You can get sick again - just maybe not as sick as last time.
In genetic drift, some antibodies
still recognize the antigen, but others do not (you have a “partial” immunity but not a full one)
why did the swine flu kill so many young adults
many older people had antibodies that recognized H1 or N1 components from much earlier infection…. young didn’t
exciting news for H antigens
antibody shown to recognize all variations of all H antigens in influenza A!
yearly flu vaccines
guess he most likely flu infection to happen each year
to guess the flu
ook at data from previous years to choose the H and N subtypes most likely to be found the next year
flu vaccines are the form of
attenuated or killed version of the vaccine
flu vaccines predict the genetic -______
genetic drift of the flu virus
flu vaccines are typically
trivalent: they include three separate guesses
two guess for flu vaccine
influenza A (H1M1 and one for H3N2)
one guess for flu vaccine
influenza B
they are NOT guessing (flu)
whether the main strain is carrying H1, H3……. but which version of H1 or H3 will be carried
what is often given to flu patients
antibiotics,,,, even though the kill bacteria
most flu symptoms
caused by own immune system
flu ymptoms caused by immune system
fever, cough, mucus, inflammation
the flu also invades and kills
ciliated, mucus-secreting cells
when the flu also invades and kills ciliated, mucus-secreting cells.
reduces the defense of the airway
becuse the flu reduces the defense of the airway it is associated w/ a
secondary respiratory infection
the ______ protein in influenza has been shown to stop______
NS1 protein……. shown to stop host cell mRNAs from being completed
NS1 protein……. shown to stop host cell mRNAs from being completed …….. causes
slowing production of host porteins…… NOTEWORTHY»»> interferons
the current version of the H5N1 bird flu has
single nucleotide mutation that makes NS1 protein far more virulent
we’re lucky about H5N1 because
it’s hard to invade humans…. for now
major cytokine in the body is
TNF-a
TNF-a
tumor necrosis factor alpha
tumor necrosis factor alpha has many functions is effective @
stopping influenza infection.
release of TNF-α has been shown to be
“dose-dependent”…. more flu = more TNF-α.
dose-dependant is normally fine…… but like most cytokines TNF-a causes
inflammation, swelling, and white blood cell migration.
too much inflammation, swelling, and white blood cell migration @ site of infection
ARDS
ARDS
acute respiratory distress syndrome
acute respiratory distress syndrome
lungs swelling shut and filling with fluid
ARDS is common in flu types that
target lower respiratory tracts
ex of flu causing ARDS because it target lower respiratory tracts
like the 1918 H1N1 Spanish flu outbreak that killed 30-40 million people.
