In 2016, the highest number of cases of malaria and deaths caused by the disease were in sub-Saharan Africa. In many areas of sub-Saharan Africa, malaria is endemic (continually present) and people are at high risk of becoming infected with the Plasmodium pathogen. In high risk areas it is recommended that: • homes are provided with insecticide-treated nets (ITN) • the surfaces inside homes where Anopheles mosquitoes may rest are sprayed with insecticide. This is known as indoor residual spraying (IRS).

Mark scheme

Marking points from the official mark scheme (May/June 2020). The mark or mark type is shown in brackets.

1. [3] allow mosquito for Anopheles throughout
2. allow pathogen for Plasmodium throughout
3. any three from
4. role of Anopheles in transmission cycle; e.g. Anopheles is, a vector of Plasmodium / Anopheles passes Plasmodium from infected person to uninfected person
5. insecticide on nets and on surfaces
6. kills Anopheles before it can take blood from an infected person;
7. kills Anopheles before it can transfer blood with Plasmodium to uninfected person;
8. presence of nets
9. protect people, when sleeping / at time when Anopheles is, active / feeding;
10. general
11. prevent Plasmodium from completing its life cycle; AW
12. AVP; idea of reducing population size of mosquitoes
13. use of different insecticides on net and IRS to avoid insecticide resistance
14. [1] any one from
15. increase in the use of ITN over time;
16. decrease in the use of IRS only ;
17. proportion of population protected by ITN only has increased ;
18. [1] any one from
19. increase is not steep enough, to make a large enough difference / so disease will still be able to spread ;
20. a large proportion of the population is still at risk, so people will still contract the disease; A figures from Fig. 2.1
21. WHO targets may not be met, so hindering progress in the fight against malaria; AW
22. AVP; e.g. suggests that the, provision of / distribution of / access to, ITN is not adequate ;
23. [1] any one suggestion from
24. ITN more effective in control than IRS ;
25. more cost effective to provide ITN ;
26. lack of personnel to carry out work required for IRS ;
27. ref. to insecticide on net may be more effective at killing ;
28. AVP; e.g. outside agencies / AW, provide ITN but do not help with IRS
29. [3] any three from
30. higher concentration of antibodies ;
31. faster production of antibodies ;
32. because of presence of memory, B-lymphocytes / B cells ;
33. higher numbers of specific B-lymphocytes, so increased chance of faster recognition / because of clonal expansion in first response;
34. AVP; e.g. also more memory T-cells to stimulate B-lymphocyte response
35. ref. to higher concentration antibodies in circulation remaining after recovery
36. [2] any two from
37. result of an autoimmune disease / AW;
38. antibodies produced against, self-antigens / antigens on body cells
39. or
40. antibodies bind to self-antigens / antigens on (own) body cells;
41. detail; e.g. prevents functioning of muscle cells
42. binds to receptors on muscle cells