lqc 8a exam qs

Question 1

There is an ‘evolutionary race’ between some bacteria, such as Mycobacterium tuberculosis (TB), and their hosts. Explain how this could affect antigen presentation to T helper cells.

Answer 1

a mutation has occurred in the dna, there is a change in antigen of bacteria, memory T cells will not recognise the new antigen, primary immune response needed to activate another population of T helper cells, phagocytes are unable to recognise the bacteria so antigen presentation is not possible

Question 2

Explain why medications, other than antibiotics, are needed to treat the most severe cases of BRD.

Answer 2

viruses and bacteria involved, usually antibiotics are only effective against bacteria, other medications needed to deal with viruses

Question 3

Explain why it might be advisable to change the antibiotic being used, in the treatment of these cattle, once the pathogen has been identified

Answer 3

the antibiotic used is most effective against known bacteria, none of the antibiotics are 100% effective and some bacteria survive, some bacteria are resistant, resistant strain develops