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Viro Final Exam > Orthomyxoviridae > Flashcards

Orthomyxoviridae Flashcards

1
Q

T/F:

Attachment of Orthomyxoviruses is mediated by Hemagglutinin, adsorption, and penetration by the fusion protein.

A

False

Penetration by ENDOCYTOSIS!
Orthomyxo has no “fusion protein”

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2
Q

Influenza type(s) _____ has two types of spike proteins, one with HA that has _____ shape with homo______ and one with NA that has _____ shape with homo _____.

A. A and B; Rod, tetramers; mushroom, trimers
B. A and B; Rod, trimers; mushroom, tetramers
C. C; Rod, tetramers; mushroom, trimers
D. C; Rod, trimmers; mushroom, tetramers

A

B.

A and B have 2 different types of spikes:
Rod shaped, with homotrimers of HA
Mushroom-shaped, with homotetramers of NA

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3
Q

T/F:

Influenza C viruses lack NA, and only have one type of glycoprotein spike consisting of HA-esterase molecules that are multifunctional.

A

True

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4
Q

T/F:

Antibodies against HA will neutralize the infectivity of the virus, whereas antibodies against NA will help reduce spread from cell-to-cell but not neutralize the virus.

A

True

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5
Q

Which of the following is NOT correct for Orthomyxoviridae?

A. Negative-sense, SS linear segmented RNA genome with 6-8 segments
B. A segmented genome makes these viruses especially prone to genetic reassortments.
C. Influenza A and B have 7 segments, whereas C has 8 segments.
D. Helically symmetrical nucleocapsid
E. All of the above are correct

A

C.

Influenza A and B have 8 segments
Influenza C has 7 segments

I think A and B come first so they have more
C comes later, and is a worse grade, so gets less points

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6
Q

Which of the following is TRUE for replication of Orthomyxoviridae?

A. Replication occurs in the cytoplasm
B. Low pH in the endosome triggers fusion of viral envelope with endosomal membrane, H+ ions into the virion thru the M1 channel, then dissociation of M2 protein from Ribonucleoprotein (RNP), and RNP enters the nucleus.
C. Snatching of the 5prime methylguanosine cap from host mRNA by the virus allows the cap to be used as a primer for viral RNA transcription.
D. Budding takes place through the nuclear membrane

A

C. is correct

Replication== nucleus

H+ ions enter virion thru the M2 channel, and M1 dissociates from RNP

Budding takes place through the cytoplasmic membrane

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7
Q

Choose the CORRECT matching for Influenzaviruses:

A. Influenza A: Human pathogens
B. Influenza A: Humans, horses, swine, dogs, fowl, mink, seals, etc
C. Influenza B: Humans and Swine (rarely cause disease)
D. Influenza C: Humans, horses, swine, dogs, fowl, mink, seals, etc
E. None are correct

A

B. is correct

Influenza A= Humans, horses, canines, swine, fowl, mink, seals, whales
Influenza B= Humans
Influenza C= Humans and swine, rarely cause disease

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8
Q

T/F:

The 3 genera of Influenzaviruses, A, B, and C, are classified based on differences in their spike proteins.

A

False!

Actually it is based on differences in their NUCLEOPROTEIN and MATRIX protein!

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9
Q

T/F:

Subtypes of the different genera of Influenza viruses (example: H1N1, H7N7), are classified based on differences in their envelope spike proteins (HA and NA)

A

True!

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10
Q

T/F:

There are 18 known subtypes of NA and 11 known subtypes of HA, and there is little to no cross-protection between subtypes.

A

False.

NA=11 subtypes
HA=18 subtypes

But it is correct that there is little to no cross-protection between subtypes. That is part of why we are susceptible to flu every year- just because you had it does not mean you are protected because there are many subtypes. I think…I know it has something to do with the 8 segments and the reassortment causing there to be almost infinite combinations of flu strains.

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11
Q

Choose the INCORRECT pairing of species and Influenza subtype:

A. Equine: H7N7
B. Equine: H3N8
C. Avian: H7N9
D. Swine: H1N2
E.  Canine: H3N2
F. Horses: H1N1
A

F. Horses can only get H3N8 and H7N7

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12
Q

Which of the following subtypes of Influenza would NOT infect avian species?

A. H1N11
B. H16N9
C. H5N1
D. H7N3

A

A.

The avian Influenza virus subtypes of HA are 1-16, so any of the HA types, and NA only 1-9 (10 or 11 would not infect)

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13
Q 
Which of the following subtypes would NOT infect swine?
A. H1N1
B. H1N2
C. H3N2
D. H5N1
A

D.

The subtypes known to infect swine are H1N1, H1N2, and H3N2.

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14
Q

T/F:

Small changes in amino acid sequences via point mutations that over time cause small changes in HA and/or NA surface proteins of Influenzaviruses and allow them to develop the ability to evade pre-existing immunity is an example of genetic shift.

A

F.

Genetic DRIFT= mutations; small changes over time
Genetic SHIFT= Sudden large changes; reassortment and recombination events.

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15
Q

Which of the following Influenza viruses is seen worldwide EXCEPT for island countries such as New Zealand and Iceland?

A. Avian Influenza
B. Swine Influenza
C. Equine Influenza
D. Whale and seal Influenza

A

C. Equine

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16
Q

Which of the following is NOT a recommended method of diagnosis for Equine Influenza?

A. Antigen detection kits (Direct-o-Gen FluA Test)
B. Isolation in embryonated eggs via allantoic or amniotic routes
C. Antigen-capture ELISA
D. Nasal or Oropharyngeal swabs for RT-PCR, taken at any time during the course of infection.
E. All of the above are recommended

A

D. EARLY in the course of infection!!!

17
Q

Which of the following could be LEAST likely to be a source of infection of Influenza virus for a pig?

A. Another pig that has recovered from the virus about 2 months ago
B. A human ill with influenza virus
C. A bird ill with influenza virus that has landed in the pig’s enclosure
D. A dog infected with influenza virus
E. A horse infected with influenza virus

A

E. a horse would be LEAST likely to infect a pig because horses get H3N8 and H7N7 and swine are not known to get that one

Canines are known to fall ill with H3N2 and H1N1, both swine influenzas

18
Q

In which of the following species is the migration of ascarid larvae known to exacerbate the signs of influenza?

A. Horses
B. Swine
C. Canine
D. Avian

A

B swine

19
Q

Abortion is most associated with which subtype of HA in Influenza virus of swine?

A. H1
B. H2
C. H3
D. H4
E. H5
A

C. H3 reassortments are most likely to cause abortion

like the H3N2

20
Q

Which of the following is TRUE of testing for swine flu?

A. PCR is now the standard for routine detection, replacing virus isolation
B. PCR is done to detect the specific NA and HA
C. One reason it is important to test is because the disease can look like M. hyopneumoniae and A. pleuropneumoniae infections.
D. It is important to test because swine serve as mixing vessels for the virus and are often associated with species jumps to humans, so it is important from a public health perspective.
E. All of the above are true

A

E.

21
Q

T/F:

Equine influenzavirus has been known to infect turkeys, causing a drop in the quantity and quality of egg production and respiratory signs, as well as minks and ferrets, causing respiratory signs of varying severity.

A

False.

It is SWINE Influenza Virus

22
Q

Which of the following is NOT CORRECT about Avian Influenza Virus?

A. Classification is based on ability of virus to cause severe disease in IV inoculated young chicks in the lab
B. Classification is based on possession of genetic features associated with HPNAI viruses
C. LPNAI and HPNAI forms are both reportable
D. LPNAI viruses found in nature have always been found to have H5 or H7
E. It is also called Fowl Plague

A

D.

HPNAI viruses have always contained either H5 or H7

23
Q

T/F:

Wild water fowl generally are asymptomatic carriers of Avian Influenza Virus of the LPAI type, and domestic birds and poultry tend to be the only ones to get the HPNAI type, although the HPNAI type has been documented in wild water fowl.

A

True

24
Q

T/F:

The mechanism by which poultry get the HPNAI form of Avian Influenza is by acquiring an LPNAI form from wild birds, and it subsequently mutates into the HPNAI form if it contains either H5 or H7.

A

True.

25
Q

Which of the following is INCORRECT for Avian Influenza?

A. LPNAI viruses are not endemic in domesticated birds in developed nations.
B. HPNAI is usually not endemic in developed nations
C. H5H1 HPNAI is endemic in poultry in a few Asian and Middle Eastern countries.
D. Sometimes transmission from wild birds to domestic flocks involves in-between intermediate domestic bird (duck, sparrow) or fomites.
E. All of the above are correct

A

A.

LPNAI are not endemic in COMMERCIAL POULTRY flocks in developed nations, but may be in OTHER DOMESTICATED BIRDS.

26
Q

T/F:

Although there are ELISA kits for detection of nucleoprotein or matrix antigens of Influenza A for detection of Avian Influenza, RT-PCR is the diagnostic method of choice for most labs.

A

T

27
Q

In the U.S., the use of any vaccine for Avian Influenza requires approval from_________; Use of vaccine containing H5 or H7 requires approval from _______.

A. USDA; State veterinarian
B. State veterinarian; USDA
C. County veterinarian; state veterinarian
D. State veterinarian; county veterinarian

A

B.

28
Q

T/F:

Avian Influenza is not only reportable to national authorities- you must report it to the OIE (World Organization for Animal Health).

A

True

Viro Final Exam (19 decks)

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