Influenza Pandemics

Question 1

genome organization of type A influenza viruses

Answer 1

8 RNA segments

Question 2

Type A flu ecology

Answer 2

18 HA subtypes
11 NA subtypes
they can combine in any pair creating 149 virus combinations

Question 3

how are influenza viruses named

Answer 3

type/classification
(animal origin if applicable)
geographic origin
strain ID
year isolated
HANA

Question 4

antigenic shift vs antigenic drift

Answer 4

Shift: genetic reassortment between an avian virus and a human virus occurs in pigs to create a completely new viral strain

Drift: virus undergoes small point mutations on surface proteins during replication

Question 5

does antigenic shift or antigenic drift have a more severe impact in regards to pandemic potential

Answer 5

Shift

Question 6

transmission methods of influenza viruses

Answer 6

most common is direct transmission(cough, sneeze, etc)
less often by indirect(fomites)

Question 7

annual impact of influenza viruses(24-25 season)

Answer 7

33-56 million illness
15-25 million medical visit
430,000-910,000 hospital
19,000-92,000 deaths

Question 8

impacts of 1918 flu in US

Answer 8

-1/3 of the world population infected
-50 million deaths worldwide
-more soldiers lost to disease than combat in WWI
-killed more Americans than WWI, WWII, and Vietnam combined
-killed more in 2 months than black death did in a year
-lowered life expectancy by 12 years

Question 9

how was the 1918 pandemic controlled

Answer 9

isolation and quarentine

Question 10

how are we able to study the 1918 flu virus

Answer 10

strains found in permafrost victims, PCR systems used to recreate the genome

Question 11

how are flu vaccines prepared

Answer 11

candidate vaccine viruses are grown in embryonated chicken or mammalian eggs

Question 12

which viral proteins are targeted by antiviral drugs to treat flu

Answer 12

Neuraminidase
virus polymerase complex

Question 13

what are the four flu virus classifications

Answer 13

A,B,C,D

Question 14

What flu classification produces moderate to severe illness in humans and animals

Answer 14

Type A

Question 15

what flu classification primarily affects cattle

Answer 15

Type D

Question 16

which HA and NA subtypes exist in wild birds

Answer 16

H1-H16
N1-N9

Question 17

which HA and NA subtypes exists in bats

Answer 17

H17 and 18
N10 and 11

Question 18

why do avian flu’s transfer poorly to humans

Answer 18

chickens have a a2, 3 SA tract which is only found in the lower respiratory tract of humans, viruses from chickens struggle to bind to a2, 6 SA receptors found in the upper tract of humans

Question 19

why are pigs good intermediaries for transferring flu between birds and humans

Answer 19

they contain both a2, 3 SA and a2, 6 SA receptors in their respiratory tract

Question 20

pandemics caused by antigenic shift(years and protein ecology)

Answer 20

1918-H1N1
1957-H2N2
1968-H3N2
2009-H1N1

Question 21

fomite definition

Answer 21

a surface or object that has the virus on it

Question 22

when are people with flu viruses most contagious

Answer 22

3-4 days after illness

Question 23

symptoms of non complicated influenza

Answer 23

fever
myalgia
sore throat

Question 24

characteristics of complicated influenza

Answer 24

pneumonia
other respiratory complications
death

Question 25

natural reservoir for influenza A

Answer 25

water birds

Question 26

the 1918 flu had 3 waves, which was the deadliest, what time of year was it?

Answer 26

2nd wave fall/winter

Question 27

what age group did 2/3 of the deaths from the 1918 flu come from

Answer 27

18-50

Question 28

what trend for causing mortality did the 1918 influenza follow that differed from other flu viruses

Answer 28

it caused high mortality and severe disease in previously healthy people

Question 29

what bacteria was originally thought to be the causative agent of the 1918 flu? what does it really do?

Answer 29

Hemophilus/bacillus influenzae it caused pneumonia which often accompanied the flu

Question 30

what flu pandemic was known for its "cytokine storm" that made it very deadly

Answer 30

1918 influenza

Question 31

what does cytokine storm refer to

Answer 31

virus produced such high levels of cytokines that your body killed itself trying to fight them

Question 32

T/F when a new virus is introduced the old one disappears

Answer 32

TRUE. although it changed in 1968 with an H3N2 virus

Question 33

why do we currently have 2 active flu strains

Answer 33

an H3N2 virus was accidentally released from a lab in hong kong in 1968, however, the old strain remained

Question 34

2 current active flu ecologies

Answer 34

H3N2 H1N1

Question 35

current bird flus present

Answer 35

H5N1 H7N9

Question 36

infection and case fatality rate of H5N1 avian flu globally

Answer 36

954 cases, 49% fatality

Question 37

infection and case fatality rate of H7N9 avian flu globally

Answer 37

1,568 cases, 39% fatality

Question 38

what avian product is most heavily affected by avian influenza

Answer 38

layer hens

Question 39

how do we handle a positive case of avian flu in a flock of birds

Answer 39

the entire flock is culled

Question 40

T/F all mammals infected with avian influenza are carnivores

Answer 40

TRUE. it was likely picked up from eating infected birds

Question 41

T/F milk from a cow infected with avian influenza is not safe to drink

Answer 41

FALSE. the virus is killed during pasteurization

Question 42

what class of flu virus were present in the 23-24 season vaccine

Answer 42

2 type A 1 type B

Question 43

why do cold-adapted live strain vaccines work intranasally

Answer 43

the virus can only grow in colder areas of the body(such as the nose) and would die if it migrates

Question 44

what age range is best for flumist(intranasal vaccine)

Answer 44

2-49 years old