Respiratory Virus and Atypical Pathogens

Question 1

Difference between professional invader and secondary invader?

Answer 1

Professional invader - infect healthy respiratory tract

Secondary invader - infect comporimscied tract

Question 2

What is infection of nasopharynx and what causes?

Answer 2

Caused viruses e.g adenovirus (dsDNA)
Spread by aerosol - self limiting
Symptoms worsen if involvement lower respiratory tract

Question 3

How to virus adhere?

Answer 3

1. Adhere to cilia or microvilli on mucosal epithelium - avoid flushing
2. Infect cells - spread
3. Inflammatory response

Question 4

How do adenovirus work?

Answer 4

Attach via adhesions on the end of pentane fibres

Question 5

What in mumps and how is it caused?

Answer 5

Parmyxovirus - air-borne spread

Question 6

What causes laryngitis and tracheitis?

What are the complications?

Answer 6

Parainfluenza virus, adenovirus and influenza

Become obstructed children - croup cough (stridor inhalation)

Question 7

What causes bronchitis and bronchiolitis?

Answer 7

RSV - respiratory syncytial virus

Rhinovirus and coronavirus, adenovirus and influenza

Question 8

What is RSV and it’s pathology?

Answer 8

Pathology: create large fused cells

Cause problems infants (cyanosis and rapid RR)

Question 9

What is the influenza virus?

Answer 9

Orthomyxoviridae

Transmitted by aerosol - restricted to coldest months of year

Question 10

Viral uptake of influenza?

Answer 10

Initial infection - virus attach to silica acid receptor on epithelial cells via viral HA protein
Few days: liberated cytokines

1. HA mediate binding to sialic acid receptor
2. Internalised by endocytosis
3. Endosome acidified
4. HA mediate fusion viral envelope to endosome membrane

Question 11

Structure of influenza virus?

Answer 11

ssRNA w/ nucleoprotein and polymerases and surface glycoproteins

Question 12

What are the surface glycoproteins of influenza? (major antigens)

Answer 12

HA - haemagglutin - mediate binding

NA - neuraminidase - involved in release of virus from host cell

Question 13

Influenza classification?

Answer 13

H-antigen (HA) - 3 human adapted

N-antigen (NA) - 2 human adapted

Question 14

What is antigenic drift?

Answer 14

Small point mutation in HA/NA that accumulate over time

Result new variant virus that infect

Question 15

What is antigenic shift?

Answer 15

Result in major shift in viral composition - result new HA and NA type
Due to simultaneous infection

Question 16

How is influenza vaccine made?

Answer 16

Vaccine strain chosen - grown in embryonate hen eggs - formalin killed - detergent to split vaccine

Question 17

What do influenza vaccine contain?

Answer 17

One H3N2 strain and one H1N1 and one B strain