Introduction to respiratory infections

Question 1

Tropism

Answer 1

Phenomenon by which microorganisms are restricted to certain host, tissue, and cell types. Often determined by the availability of suitable receptors.

Question 2

systemic

Answer 2

means it affects the whole body

Question 3

which disease is the second most common cause of death in children < less than 19. to neonatal and preterm birth.

Answer 3

Pneumonia.

Question 4

what are barriers of infection?

Answer 4

mucus- removed by coughing and sneezing
cilia-muco-cilia escalated moved trapped micro-organism upwards

Question 5

name the soluble factors of the innate immune system.

Answer 5

Lysozyme, complement, acute phase protein. e.g.
cells= phagocytes and innate lymphoid cells

Question 6

how respiratory pathogens overcome a host defenses 1.

Answer 6

They attach to respiratory epithelium.
They inhibit the ciliary activity.

Question 7

Which environmental factors that can inhibit cilliary activity?

Answer 7

pollution, cigarette smoking, very dry air

Question 8

which people are at great risk of respiratory infections ?

Answer 8

people with cystic fibrosis and chronic lung disease.

Question 9

H?ow respiratory pathogens overcome host defences 2

Answer 9

They avoid killing by alveolar macrophages
* M. tuberculosis, Legionella
* Note: Macrophages may be disabled by prior exposure to asbestos and other dusts. Smoking
also decreases activity of macrophages. These environmental factors predispose people to
respiratory infection

Question 10

Respiratory pathogens: Difference between professional and secondary invader?

Answer 10

Professional ones are able to infect even health respiratory tract because they have
mechanisms to overcome intact host defenses.
Secondary invaders only cause infection once host defences have been weakened in
some way.

Question 11

There are a few exceptions where pathogen invades via respiratory tract but causes systemic infection: which pathogens?

Answer 11

Mycobacterium tuberculosis
* Legionella
* EBV
* Measles.

Question 12

Transmission of infection

Answer 12

From infected respiratory epithelial cells
* Spread by host activity
by coughing
sneezing
especially with increases secretion

Question 13

some respiratory pathogens are not stable in environment due to :

Answer 13

1.susceptible to dehydration, heat.
2.exceptions: TB protected by liquid-rich cell wall
non-enveloped viruses also relatively stable.

Question 14

Who is at increased risk of respiratory infections?

Answer 14

Age
* Very young
* (Very) old
* Impaired immune status
* HIV
* Splenectomy
* Alcohol
* others
* Preceding viral respiratory infection
* Underlying lung diseases
* Cystic fibrosis
* Bronchiectasis
* Cigarette smoking and pollution
* Those with increased risk of exposure to pathogens (as stated on previous slide)