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Flashcards in Orthomyx Deck (61):
1

Orthomyxovirus shape

pleomorphic

2

Orthomyxoviruses cause ___ and ____ infections

URI and LRI

3

______ is the most common complication of Orthomyxovirus

Pneumonia

4

Orthomyxovirus types

Influenza A, B, C

5

Influenza type ___ is the most virulent

A

6

Who does Influenza A infect?

humans and wide variety of animals (Birds, swine, seals, horses)

7

Who does Influenza B infect?

Only humans

8

Who does Influenza C infect?

Humans and Swine

9

Rarest Influenza is...

C

10

Influenza B epidemics are ____ because they ____

Mild, mutate slowly

11

Most people have antibodies against the ___ strain of Influenza

B

12

Types of Influenza that are included in the vaccine

A + B

13

Types of Influenza that cause human epidemics

A + B

14

Influenza virus genome (type and segmentation)

ss(-)RNA, segments = 8 for A/B, 7 for C

15

Influenza surface proteins

M1/2, Neuraminidase + Hemagglutinin

16

Influenza M1 protein function

forms a layer under the host cell membrane

17

Influenza Capsid shape

helical

18

Influenza enveloped or non?

Enveloped

19

Hemagglutinin functions by...

binding to sialic acid

20

Neuraminidase function

Hydrolyze sialic acid

21

Influenza B doesn't have ____

M2 Protein

22

Locations of Influenza replication, assembly, and budding

Replicates in NUCLEUS, assembles in CYTOPLASM, buds at PLASMA membrane

23

Influenza steps of replication (6)

hemagglutinin BINDS to sialic acid ----- virus is internalized in ENDOSOME ------ endosome ACIDIFIES and capsid and vRNA are released ------ vRNA goes to NUCLEUS ----- mRNA is SYNTHESIZED ---- mRNA TRANSPORTED to cytoplasm for protein synthesis.

24

Viral RNA polymerase type and subunits

vRNA-dependent RNApol, PA/PB1/PB2

25

Naked influenza virus assembles in the ____ after undergoing _____

nucleus, secondary transcription

26

Why does influenza replicate in the nucleus

it doesn't Cap or Polyadenylate it's mRNA (it has to steal the machinery from the host cell)

27

Incubation time for influenza

2 days

28

Primary complication of influenza

PNA

29

Who is especially at risk for influenza

Women in third trimester of pregnancy ----- elderly -----people with CVD

30

Primary influenza PNA is further complicated by...

secondary bacterial PNA

31

Bacterial PNA from influenza... what pathogens?

S aureus, Strep Pneumo, H. Influenzae

32

Which type of bacterial PNA is most serious?

Staphylococcal PNA

33

Sx of Bacterial PNA

elevated WBC, bloody cough, CAVITARY infiltrate on chest Xray

34

Non pulmonary complications of influenza

Myositis----Cardiac----Reye's----Encephalitis

35

Reyes Sx

swelling of liver and brain, neuro sx and loss of consciousness

36

Encephalitis is a complication of ________

influenza B

37

Who is extremely susceptible to influenza-induced encephalitis

people younger than 7 or older than 55

38

Influenza pathogenesis

establish URI by killing epithelial cells (mucus and ciliated) ---- NA cleaves Sialic acid giving access to tissue ---- Desquamation ----- inflammatory cell response ---- Interferon & cytokine responses

39

Influenza spread by

AIR (droplets) and FOMITES

40

Influenza is stabile in...

low temp and low humidity

41

Seasonal Influenza is a result of...

antigenic DRIFT. New strain may require a different vaccine.

42

Pandemic Influenza is a result of...

antigenic SHIFT of surface proteins. Whole population at risk.

43

There are __ subtypes of HA and __ subtypes of NA

16 HA 9 NA

44

Which subtypes (for HA and NA) are known to circulate widely in humans

H-1,2,3 N-1&2

45

The only influenza HA strains known to cause pandemics are...

H1, H2, H3

46

Ag Drift results from

point mutations

47

Antigenic shift results from

exchange of a gene segment (REASSORTMENT) -- Due to recombination with another genome of a different antigenic type

48

Three ways Antigenic shift can occur

Example = Strain jumps through intermediate without changing.... Strain jumps to humans without changing...... or the intermediate gets strain from BOTH humans and bird and reassortment occurs

49

Hemagglutinin binds to

sialic acid

50

Human flu HA binds to...

alpha 2,6 sialic acid

51

Bird flu HA binds to

alpha 2,3 sialic acid

52

___ have both types of sialic acid receptors, which allows for greater chance of _____ to occur

Pigs......Reassortment

53

Humans do, in fact, carry SOME _____, mostly in the trachea

alpha 2,3 sialic acid sequences

54

Influenza antiviral drugs

Zanamivir, Oseltamivir.... Adamantanes

55

Zaltamivir and Oseltamivir are active against what?

Influenza A + B

56

Difference in administration of Zaltamivir and Oseltamivir

Zan = inhalation....... Oselt = Oral

57

Adamantanes block

M2 protein --- entry into the endosome & viral release

58

Influenza vaccine types

Trivalent and Live attenuated

59

Trivalent flu vaccine is what type?

inactivated.

60

Trivalent vax made how? How does it protect?

egg grown virus, protects via IgG

61

Live attenuated influenza vaccine approved for ____ administration to ________ (patients)

nasal........non-pregnant 2 - 49 year olds