Question 1

1. Give the full scientific name of one of the protist speciesthat causes malaria. (1 mark)
2. Briefly explain how the complexity of the malaria life cycleinfluences the host’s immune response.
3. Name one diagnostic test appropriate for use in the diagnosisof a current malaria infection and explain how it works.
4. State two strategies to prevent malaria.

Question 2

1. New variants of influenza can be generated by processes knownas antigenic drift and antigenic shift. Distinguish between thesetwo processes.
2. How might antigenic drift affect the design of a vaccinationprogramme for influenza?
3. RT-PCR can be used to identify an influenza infection. Stateone other diagnostic test for influenza and describe how it can beused to determine the subtype of influenza.

Question 3

Read the following three statements and then answer the questionbelow.

• In 2019, the UK lost its ‘measles-free’ status.
• The basic reproduction number for measles (R0) is given asbetween 12 and 18, in different studies.
• The immunisation rate in the UK for measles dipped to a lowpoint in 2003 to 80% coverage and since then has risen to 91% in2019.

Explain, using calculations, the causal link between these threestatements and briefly discuss whether there is any prospect of theUK regaining its ‘measles-free’ status in the next 5 years.

Question 4

Cholera is an acute diarrhoeal disease endemic in some areas butprone to resurgences in pandemics.

1. What is the primary cause of death in cases of cholera?
2. What is the normal habitat of Vibrio cholerae? (1 mark)Describe one way in which people can become infected (1 mark) andone step that an individual could take to minimise that risk ofinfection (1 mark)
3. A stockpile of oral cholera vaccine is maintained by the WHOfor use in humanitarian crises and outbreaks. From your knowledgeof the biology of cholera infection, and referring to aspects ofthe appropriate immune response, explain why oral vaccines areused.
4. A freak weather event on a large tropical island destroyshousing and leads to the local population being rehoused in acramped refugee camp, where a cholera epidemic soon occurs. Apartfrom distributing oral cholera vaccine, what additional publichealth measures should be taken in the refugee camp to limitfurther infection and/or deaths from cholera?

Question 5

1. Your friend is suffering from a fever and respiratory symptoms.She visits her GP and requests antibiotics. Explain why antibioticsmay not be appropriate for her infection.
2. Describe the effects of the overuse of antibiotics on thebacterial population in humans.
3. In order to distinguish between viral and bacterial infectionssome GPs now use a rapid point-of-care (POC) test for levels ofC-reactive protein (CRP). Explain the role of CRP in the immuneresponse and its relevance to use in this test.
4. In a hospital setting, treatment with antibiotics is a riskfactor for infection with Clostridium difficile. Explain whyClostridium difficile is commonly acquired in hospitals.

Question 6

1. The cytokine IFNγ is produced by Th1 cells. Outline threedifferent functions of IFNγ in inflammation and/or the immuneresponse.
2. Name one cytokine that is produced specifically by Th2 cellsand state what effect it has on its target cell(s).
3. What advantage is there for the host in having two distinctpatterns of immune response, controlled by Th1 and Th2 cells?