L12 RNA virus and the disease they cause

Question 1

Influenza Virus family

Answer 1

Orthomyxoviridae

Question 2

Influenza Virus characteristics

Answer 2

• ss - sense RNA
• RNA segmentaed
• Each segment will code for 1 or 2 proteins
• Enveloped gp: hemagglutinin and Neuraminidase (NA) needed for entry and egress of virus to host

Question 3

Influenza is caused by

Answer 3

Orthomyxoviridae

Question 4

Myxo meaning

Answer 4

Greek for mucous

Question 5

What does the “myxo” in orthomyxoviridae mean for influenza

Answer 5

IV attach to mucoproteins on cell surface

Question 6

3 Gernera of influenza that infect humans

Answer 6

1. IV A (H1-18)
2. IV 2 (B/yamagata)
3. IV 3 (Mild, inapparent)

Question 7

Influenza A Characteristics

Answer 7

• undergo a genetic shift
• cause pandemics

Question 8

Minus sense ssRNA undergo mutations and can cause what?

Answer 8

Reassortment: high rates of antigenic variation

Question 9

Reassortment:

Answer 9

high rates of antigenic variation

Question 10

How often does swine flu circulate in pigs

Answer 10

Throughout the year

Question 11

Does swine flu infect humans

Answer 11

No normally but sporadic human infections can happen if exposed to an infected pig

Question 12

Can vaccines against human IV protect against swine flu

Answer 12

No

Question 13

Pathogenesis of Influenza

Answer 13

• Infect upper respiratory tract
• Virus replicates in epthelial cells in nose killing them
• Production of IFN and cytokines -> severe malaise
• Can infect lower repiratory tract and cause pneumonia bc virus replicates in alveolar pethelial cells
• IV infection also enhance stroke and heart disease

Question 14

Avian IV dominates preference for what?

Answer 14

Alpha-2,3 sialic acid
or alpha 2,6 in humans

Question 15

Genetic reassortment is the mixing of RNA via what and results in what?

Answer 15

Co-infections of host cells by > 1 IV that results in the formation of IV with new genomes (to human immune systems)

Question 16

Genetic reassortment has severe disease and high death rates (T/F)

Answer 16

True

Question 17

Influence antigenic changes

Answer 17

The structure of hemagglutinin and neuraminidase periodically change

Question 18

Influence antigenic change: Shift (pandemic)

Answer 18

• Major change, new subtype
• Exchange gene segments (reassort): virus is immunologically distinct from the previous IV so there is no existing immunity.

Question 19

Influence antigenic change: Drift (Epidemic)

Answer 19

• Minor change, same subtype
• Point mutations in HA/NA genes and can’t control replication.

Question 20

Epidemics are an antigenic ____

Answer 20

Drift

Question 21

Pandemics are an antigenic _____

Answer 21

Shift

Question 22

Season Influenza

Answer 22

Respiratory illness transmitted person to person
- Vaccines and immunity

Question 23

Avain Influenza

Answer 23

• Occur naturally in wild birds
• No human immunity or vaccine

Question 24

Swine Influenza

Answer 24

• Respiratory disease of pigs by IV-A and cause outbreaks
  _ Not infect human normally but can happen sporadically as H1N1v

Question 25

Pandemic Influenza

Answer 25

- Virulent human Influenza that cause global outbreak - Little natural immunity - Easily transmittable between humans

Question 26

Coronavirus RNA characteristics

Answer 26

* +pos sense * enveloped * non-segmented RNA with large genome

Question 27

MERS-CoV

Answer 27

Middle East Respiratory Syndrome Coronavirus

Question 28

MERS-CoV information

Answer 28

* in camels * Camels don't show signs of infection but can spread the disease in fluids * 35% mortality

Question 29

Human immunodeficiency virus family and genus

Answer 29

Retroviridae and lentivirus

Question 30

Human immunodeficiency virus shape and characteristics simple

Answer 30

* Icosahedral * Enveloped * ss(+) RNA

Question 31

Human immunodeficiency virus Infects what

Answer 31

CD4+ cells with gp120

Question 32

Human immunodeficiency virus replication

Answer 32

* By conversion of vRNA to complementary DNA (vRT) * Integrates into host with (v)Integrase * Known as a provirus at this stage and ramians integrated for cell's life * HIV is a quasispecies

Question 33

HIV-1 and HIV-2 both arose from what

Answer 33

Non-human primates in West Africa

Question 34

HIV-1 came from

Answer 34

Chimpanzees and is the cause of almost all human infection

Question 35

HIV-2 is related to

Answer 35

Simian immunodeficiency virus and is a less aggressive disease progression

Question 36

Which group is the main circulating recombinant form of HIV-1

Answer 36

group M

Question 37

HIV transmission

Answer 37

Percutaneous - Injection - Transfusion from donors - Occupational - nurses Permucosal - Perinatal in-delivery or breast milk - Sexual transmission across mucosal membranes in urogenital tract and rectal mucosa

Question 38

What happens to the CD$ t-cell count after HIV infection without antivirals

Answer 38

CD4+ T-cell count gradually and consistently declines

Question 39

Diagnosis of AIDS

Answer 39

Low CD$+ t-cell count of <200 cells Pneumocystis jiroveci or one illness

Question 40

Long term non-progression

Answer 40

* had stable CD4+ counts after given blood from infected donor * Attenuation of the HIV-1 genome, the nef gene, interferes with viral replication and can influence disease outcome

Question 41

Resistance to infection with HIV-1: CCR5-∆32

Answer 41

* HIV target T-cells via CD$ and coreceptors * Slow progressors were homozygous for 32bp deletion in CCR5 gene * More freq in north europe

Question 42

[Resistence to HIV-1] CCR5 432 mutation expressed on what cells?

Answer 42

* receptor molecule expressed on T-cells, macrophages, dendritic cells, and microglia microglia * Ligands are MPI1a, MPI1B, RANTES *32 base pair deletion within coding region results in a frameshift and generates a non-function receptor for HIV-1