Influenza

Question 1

Haemagglutinin

Answer 1

500 H spikes/viral
particle
- Fuses viral envelope to host cell plasma
membrane to initiate infection.

Question 2

Neuraminidase

Answer 2

100 N spikes/viral
particle
- Releases virus from host cell surface

Question 3

epidemic

Answer 3

seasonal influenza, as a result of antigenic drift.

Question 4

pandemic

Answer 4

global epidemic

Question 5

Antigenic drift

Answer 5

gradual change that occurs to antigens of the influenza virus over time.

Question 6

antigenic shift.

Answer 6

Antigenic shift is a significant and abrupt change in the antigens of an influenza A virus, resulting from the reassortment of genetic material between different influenza virus strains. This process can lead to the emergence of a new influenza A virus subtype that is markedly different from previously circulating strains and can cause influenza pandemics due to the lack of pre-existing immunity in the population.

Question 7

influenza A

Answer 7

IS CAUSEs epidemics - seasonal influenza (antigenic drift) and global epidemic.

causes severe disease- undergoes antigenic shift and drift.

and can infect animals

Question 8

Influenza B

Answer 8

generally, causes mild disease.
no animal reservoirs.

has antigenic drift only.

Question 9

How does Influenza A virus re-assortment happen?

Answer 9

Influenza viruses can undergo genetic change when they spread
through host species
* Re-assortment/recombination of segmented RNA can occur during viral replication and result in a
progeny virus (with novel H and N antigens) when 2 Influenza virus strains infect the same host cell
simultaneously.

Question 10

Spanish flue pandemic

Answer 10

due to H1N1 influenza virus.

Question 11

• Other pandemics (incl. 2009 H1N1 pandemic) occurred as result of genetic reassortment

Answer 11

when the host has been infected by avian strain an human strain at the time

Question 12

swine flu affected:

Answer 12

Children and younger adults, pregnant women hospitalized. Obese patients and
patients with chronic neurological disorders developed complications

Question 13

clinical symptom of influenza virus

Answer 13

chills
fever
malaise
headache
shivering
photophobia
dry throat. runny nose dry cough

Question 14

Complications

Answer 14

Damage to respiratory epithelium predisposes to secondary bacterial infections
* Secondary bacterial infections include pneumonia,sinusitis and otitis media

Question 15

what causes secondary bacterial infections?

Answer 15

-Staphylococcus aureus, Streptococcus pneumonia, Haemophilus influenzae
-Primary viral pneumonia (hemorrhagic)
-Myositis, rhabdomyolysis
-Myocarditis, pericarditis

Question 16

The best modality to prevent influenza.

Answer 16

is to have influenzas vaccination.

Question 17

Influenza Post exposure chemoprophylaxis.

Answer 17

Not recommended in view of widespread Oseltamivir resistance. * If PEP (Post-exposure prophylaxis) absolutely necessary (eg. severely
immunocompromised patients) – treatment doses of Oseltamivir (Tamiflu®)
recommended.

Question 18

DRUG TREATMENT that was previously used for influenza A

Answer 18

Amantadine and rimantadine

Question 19

Treatment drug used t o treat influenza

Answer 19

M2 ion channel blockers that affect intracellular viral uncoating
* Now, Neuraminidase inhibitors (Oseltamivir/ Tamiflu® and Zanamivir) favoured
* Active against both Influenza A and Influenza B

Question 20

avian influenza virus

Answer 20

Avian influenza viruses spread by movement of poultry and poultry products, live
poultry markets and unhygienic practices, and backyard flocks that are not
controlled.

Question 21

avian influenza virus strain

Answer 21

H5N1 AND H7N7