Evaluate disease prevention and control
Compare biological, social and economic factors that shape prevention and control of cholera, malaria, TB and HIV.
Section 10.1 · Infectious diseases
Cambridge International AS & A Level Biology 9700, 2028–2030 syllabus, Version 1. Educational biology content only: it does not diagnose illness or replace advice from a qualified health professional.
Before you begin
- A pathogen is a disease-causing microorganism or infectious agent; transmission describes how it passes between hosts.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which intervention most directly targets the mosquito route of malaria?
What you will learn
- Discuss biological factors relevant to disease control
- Discuss social and economic factors and connect interventions to transmission routes
WHO background: how vaccines work. The plotted values and practice records are invented teaching examples.
Build the explanation
Effective control is shaped by biology, society and resources. Biological factors include the pathogen's transmission route, vector ecology, pathogen variation and whether prevention tools such as vaccines are available. Social factors include housing density, ventilation, education, stigma, trust and whether safe behaviours are practical. Economic factors include household and public-system ability to fund clean water, sanitation, insecticide-treated nets, vaccination, testing, diagnosis, treatment and surveillance. Strategies must match the route: water and sanitation for cholera, vector control for malaria, ventilation and case detection for TB, and education, testing and prevention access for HIV.
Apply it carefully
A strong discussion weighs benefits, limits, coverage, acceptability and cost. A low-cost intervention may have limited effect if infrastructure or access is missing; a biologically effective intervention may be rejected if trust or stigma is not addressed. Combine measures across individuals, health services and communities. Avoid implying that any one intervention eliminates disease or that people affected are to blame.
Pause and explain
Why include social and economic factors when discussing disease control?
Worked example
Why can safe water and sanitation reduce cholera transmission?
Show the worked solution
- Connect the intervention to the route.
- It reduces the chance that food or water carries V. cholerae between hosts.
Answer Safe water and sanitation interrupt the contaminated-food/water route by reducing faecal contamination and exposure to Vibrio cholerae.
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Give one biological, one social and one economic factor that can affect cholera control.
Give me a hint
Choose a pathogen-route feature, a community condition and a resource constraint.
Compare my reasoning
- Biological: the bacterium spreads via contaminated food/water.
- Social: sanitation and hygiene practices; economic: funding and access to safe water infrastructure.
A biological factor is V. cholerae transmission through contaminated food or water. A social factor is whether households have reliable sanitation and hygiene information. An economic factor is whether communities and public services can fund safe water and sewage infrastructure.
Look for these in your work
- Biological route named
- Social factor described
- Economic factor described
Explain why malaria-control plans often combine vector control with community access measures.
Give me a hint
Link the vector biology to coverage and use.
Compare my reasoning
- Vector control reduces exposure to infected mosquitoes.
- Access, cost, housing and community trust affect whether measures can be used consistently.
Vector control targets the mosquito route, but its effect depends on reach and sustained use. Cost, housing conditions, access to nets or other protection, local mosquito ecology and community trust can affect coverage, so biological and social/economic planning must be considered together.
Look for these in your work
- Vector route matched
- Access and context factors considered
- No single-measure guarantee
A TB-prevention campaign offers information but ignores overcrowded, poorly ventilated housing. Evaluate one strength and one limitation.
Give me a hint
Separate individual knowledge from conditions that change exposure.
Compare my reasoning
- Information can improve understanding and encourage help-seeking.
- Crowding and poor ventilation can maintain airborne exposure, limiting the campaign's impact.
Education may improve understanding of airborne transmission and encourage earlier help-seeking. However, if crowded, poorly ventilated spaces remain unchanged, exposure opportunities can persist. Control should combine information with feasible improvements in ventilation, access to testing and treatment, and local resources.
Look for these in your work
- Strength identified
- Structural limitation identified
- Combined strategy proposed
Common mistakes
- Listing interventions without linking them to transmission route
- Ignoring affordability, infrastructure, stigma or access
- Blaming individuals or claiming one intervention guarantees elimination
What can you explain now?
Which intervention most directly targets the mosquito route of malaria?
Compare with the explanation
Vector control and reducing mosquito bites
The control should address the biological vector that transmits Plasmodium.
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Make it stick
How do biological route, social context and economic access shape disease prevention?
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