Systemic Infection

Question 1

What is Trichinella?

Answer 1

Helminth parasite naturally occurring in rats, which infects pigs and humans

Question 2

What are the two stages of Trichinella infection?

Answer 2

Enteral (localised to GI tract) and parenteral (infects other organs, e.g. muscle)

Question 3

What makes up the mucous layers?

Answer 3

Secreted mucins and transmembrane proteins (non-secreted mucins) that make up the inner mucus layer).

Question 4

What happens once a pathogen interacts with transmembrane mucins?

Answer 4

Stimulated mucous secretion
Mucin granules expand on hydration and surround pathogen with mucous containing antimicrobials
Mucin is shed from the cell

Question 5

How can pathogens overcome the mucous barrier?

Answer 5

Flagella-mediated motility
Enter via M cells in microfolds of GI tract which do not have mucous.
Toxin secretion (disrupt tight junction, block epithelial cell growth, block mucous secretion)
Use cilia and mucous movement to spread

Question 6

Which branch of the immune system is important for systemic infection?

Answer 6

Adaptive

Question 7

Which branch of the immune system is important for local, surface infection?

Answer 7

Innate

Question 8

Why can mycobacterium leprae only cause leprosy at extremities?

Answer 8

Its activity is temperature-dependent.

Question 9

What is the site of measles virus replication?

Answer 9

Lymph

Question 10

What family of viruses does measles belong to?

Answer 10

Paramyxovirus

Question 11

Is measles a DNA or RNA virus?

Answer 11

RNA

Question 12

Is measles -ve strand or +ve strand?

Answer 12

-ssRNA

Question 13

What two cell types does measles infect first?

Answer 13

Dendritic and macrophages

Question 14

In what cells does measles first replicate?

Answer 14

Lymphocytes

Question 15

Following replication in lymphocytes, what tissues does measles infect, in order?

Answer 15

Respiratory tract, mucosa, skin.

Question 16

What is the R0 of measles?

Answer 16

15-20

Question 17

What makes measles susceptible to vaccination?

Answer 17

It infects the naive population

Question 18

What bacteria causes syphilis?

Answer 18

Treponema pallidum

Question 19

What are the four stages of syphilis?

Answer 19

Primary, secondary, latent and tertiary

Question 20

Describe the primary stage of syphilis.

Answer 20

Chancre at site of infection. Persists 3-6 weeks.

Question 21

Describe the secondary stage of syphilis.

Answer 21

4-10 weeks after initial infection.
Infection of macrophages and spread to various parts of the body
Resolve after 3-6 weeks
25% recurrence 
Lesions at extremities 
Systemic

Question 22

How does Treponema pallidum avoid the immune system in the latent stage of syphilis?

Answer 22

Lipid-rich surface

Question 23

Are people with tertiary syphilis infectious?

Answer 23

No

Question 24

What is syphilis treated with?

Answer 24

Penicillin or doxycyclin if allergic to syphilis

Question 25

Why was syphilis treated with malaria?

Answer 25

The fever (41 degrees) killed syphilis bacteria