Adapting to host biology

Question 1

Barriers to an oral route of infection

Answer 1

• keratinised epithelium

- proteolytic stomach

Question 2

Conditions from the duodenum to the colon are not (a). Shown by what parasitic infection?

Answer 2

a) homologous

b) Tachygoneita of Greek tortoise

Question 3

How do parasites know when to stop development?

This is an example q

Answer 3

example shown by ASCARIS that requires 3 weeks at 30 degrees

- triggered by high CO2 and a low pH

Question 4

a) How do parasites get through percutaneous (skin)?

b) How does Schistosoma mansoni get through dermis and epidermis after recognising temperature gradients?

Answer 4

a) - directly through intact tissue
- through lesion by arthropod mouthparts

b) proteolytic enzymes

Question 5

Ascaris as an example is used again to demonstrate host (a) where eggs develop in (b), penetrate the alveolar walls, are swallowed by the (c) and develop in the small intestine.

Answer 5

a) migration
b) lungs
c) trachea

Question 6

Why as a parasite would you synchronise your life cycle with host?

Answer 6

• allows maximum protective effort

- ensure plentiful supply of susceptible hosts