Detailed specific example of the strategies used by one country to prevent and control malaria

Cambridge IGCSE/A‑Level Geography – Pathogenic Diseases: Malaria Control Strategies

1. Syllabus Overview

This set of notes links every AS‑level topic (Papers 1, 2 and 4) to a single, detailed case study – Sri Lanka’s Malaria Elimination Programme (1990‑2016). The aim is to show how physical and human geography interact with disease control, and to provide the data‑handling and evaluation skills required for the Cambridge examinations.

Key Geographic Concepts (relevant to all papers)

• Scale: Local (village), national (Sri Lanka), regional (South‑Asia), global.
• Place: Physical environment (climate, topography, water bodies, geology) and human environment (population density, settlement patterns, land‑use).
• Change over time: Trends in malaria incidence, vector‑control technologies, urbanisation, climate change.
• Systems & interactions: Climate ↔ hydrology ↔ land‑use ↔ health systems ↔ socio‑economics.
• Diversity, equality & inclusion: Rural‑urban risk differentials, gendered access to treatment, migrant‑worker vulnerability.

2. Paper 1 – Physical Geography

2.1 Atmospheric Processes

• Temperature & rainfall: Warm, humid lowlands (average 27‑30 °C) and monsoon rainfall (≈ 2 500 mm yr⁻¹) create ideal breeding conditions for Anopheles mosquitoes.
• Monsoon dynamics: Driven by the seasonal migration of the Inter‑tropical Convergence Zone (ITCZ) and the Hadley‑cell circulation.
  • South‑west monsoon (May–July) → peaks in the western and southwestern districts.
  • North‑east monsoon (October–December) → peaks in the north‑east provinces.
• Energy‑budget link (AO1): Monsoon intensity is controlled by the balance of short‑wave solar radiation (high albedo over the Indian Ocean) and long‑wave radiation loss from the land surface, producing the pressure gradient that drives moist on‑shore flow.
• Climate‑change relevance (AO2): Projected temperature rises of +1.5 °C could shift suitable vector habitats to higher altitudes (> 1 500 m) and extend the transmission season.

2.2 Hydrology & River Processes

• Drainage‑basin framework (inputs, stores, transfers, outputs): The Mahaweli River basin – Sri Lanka’s largest – illustrates the syllabus model:
  • Inputs: Monsoon rainfall, upstream runoff.
  • Stores: Reservoirs (e.g., Victoria, Kotmale), groundwater aquifers.
  • Transfers: Irrigation canals, flood‑plain channels.
  • Outputs: River discharge to the Indian Ocean.
• Stagnant water & vector habitats: Rice paddies, irrigation canals, abandoned containers, and flood‑plain pools provide larval sites.
• Flood‑hazard management (hard & soft engineering):
  • Hard: Concrete embankments, spillways, and regulated releases from reservoirs to reduce prolonged standing water.
  • Soft: Community‑led drainage cleaning, wetland restoration, and “dry‑season” water‑level management to break mosquito breeding cycles.
• Data‑handling skill: Interpreting hydrographs and rainfall‑malaria incidence graphs; calculating Pearson correlation coefficients (r ≈ 0.78 for 1995‑2005 data).

2.3 Earth Processes (Geology, Soils & Mass Movements)

• Geological setting: Sri Lanka sits on the north‑eastern edge of the Indo‑Australian plate; uplifted central highlands create steep gradients that accelerate runoff into the Mahaweli basin.
• Soil types: Clay‑rich soils in lowland flood plains retain water longer, increasing larval habitat persistence; lateritic soils in the highlands drain quickly, limiting vector breeding.
• Land‑use change & mass movements:
  • Deforestation for tea and rubber plantations created sun‑lit pools favoured by Anopheles culicifacies.
  • Landslide‑dammed ponds (common after heavy monsoon rains) become temporary breeding sites; mitigation includes slope stabilisation and drainage of impounded water.
• GIS application (AO2): Overlay of elevation, soil texture, and land‑cover layers to produce a vector‑habitat suitability map (risk index 0‑10).

2.4 Climate Change & Future Scenarios (Global Themes)

• Modelled shift of the malaria transmission zone 200 km north‑east by 2050 under RCP 4.5.
• Potential emergence of *P. vivax* in previously unsuitable highland districts.

3. Paper 2 – Human Geography

3.1 Population & Migration

• Population structure (age‑sex pyramid, 2015):

  Age group	% of total
  0‑14	27 %
  15‑64	66 %
  65 +	7 %

  High proportion of children under five increases the vulnerable population for malaria.
• Demographic transition: Sri Lanka is in Stage 3 (declining birth rates, low mortality). The slowing population growth reduces pressure on new breeding sites but urban migration creates new exposure risks.
• Internal migration patterns: Seasonal agricultural labour moves from high‑risk rural districts (North‑East) to urban construction sites on the Western coast, facilitating parasite spread.
• Health‑equity issue: Migrant workers often lack registration with public health facilities, limiting access to free diagnosis and treatment.

3.2 Water Resources & Management

• Physical water security: Availability of safe, standing‑water‑free water for domestic use and irrigation.
• Economic water security: Affordability of water‑treatment chemicals and larvicides for smallholder farmers.
• Supply‑side measures: Construction of drainage channels, reservoir‑based flow regulation, and targeted larviciding of irrigation canals.
• Demand‑management strategies:
  • Community education on covering water storage containers.
  • Incentive schemes (subsidised water‑storage lids) to reduce open water bodies.
  • Pricing policies that discourage wasteful water use in high‑risk zones.
• Data skill: Calculate per‑capita water use (m³ person⁻¹ day⁻¹) and relate it to a “vector‑habitat index” derived from GIS.

3.3 Urban Areas & Infrastructure

• Urban‑rural gradient: Slums in Colombo and Galle have poor drainage, creating micro‑habitats; peri‑urban farms retain irrigation water that bridges the rural‑urban risk gap.
• Infrastructure projects: Road and housing construction can generate temporary pools; mitigation includes pre‑construction drainage plans and post‑construction habitat‑removal checks.
• Cross‑sector integration: New public‑housing schemes incorporate screened windows, eave tubes, and mandatory indoor residual spraying (IRS) protocols.

3.4 Socio‑Economic Impacts

• Lost labour days: 3 % of annual GDP (≈ US$ 250 million) before 2000; fell to <0.1 % by 2016.
• Education: School absenteeism among children under five dropped from 12 % to 2 % after universal ITN distribution.
• Health‑care costs: Shift from costly inpatient treatment to free outpatient rapid‑diagnostic‑test (RDT) services.

4. Paper 4 – Global Themes: Disease & Geography

4.1 Causes & Effects of Malaria

• Biological cause: *Plasmodium* parasites (*P. falciparum*, *P. vivax*) transmitted by female Anopheles mosquitoes.
• Environmental drivers: Climate (temperature ≥ 18 °C, humidity ≥ 60 %), water bodies, land‑use (rice, irrigation), geology (soil water‑holding capacity).
• Socio‑economic effects: Reduced agricultural productivity, increased health‑care expenditure, hindered human capital development.

4.2 Spatial Variation of Malaria Risk (Sri Lanka)

4.3 Systems Approach to Elimination

1. Surveillance – electronic case notification (MSIS) within 24 h.
2. Rapid Response – investigation, confirmation, treatment, focal vector control within 48 h.
3. Treatment – ACT for *P. falciparum*, chloroquine for *P. vivax*; free at all public facilities.
4. Vector Control – ITNs, IRS, environmental management, larviciding.
5. Community Education – media campaigns, school modules, village health committees.
6. Monitoring & Evaluation – annual epidemiological review, performance indicators, adaptive management.

Diagram suggestion: Flowchart “Sri Lanka Malaria Elimination Cycle” showing the feedback loop from Monitoring back to Surveillance.

4.4 Challenges & Adaptive Management

• Insecticide resistance: Detected in 2012 (pyrethroids). Response – rotation to organophosphates, introduction of *Bacillus thuringiensis* (biological larvicide), and research into next‑generation nets.
• Funding sustainability: Shift from Global Fund grants to a dedicated domestic budget line (≈ US$ 12 million yr⁻¹) in 2014.
• Technology integration: Mobile reporting app reduced case‑notification time from 48 h to 12 h (2015).
• Cross‑sector collaboration: Ministries of Health, Agriculture, Local Government, Education; partners WHO, UNICEF, NGOs; vector‑control criteria embedded in irrigation and urban‑development plans.

4.5 Diversity, Equality & Inclusion

• ITN distribution prioritised pregnant women and children <5 years (95 % coverage by 2016).
• Female community health volunteers trained to conduct RDTs and health‑education visits, improving uptake in remote villages.
• Special outreach programmes for migrant labourers (Arabic‑language leaflets, mobile clinics at construction sites).

4.6 Outcome Summary (1990‑2016)

5. Assessment Objectives & Data‑Handling Skills

• AO1 – Knowledge & Understanding: Define malaria, describe the life‑cycle of *Plasmodium*, list vector‑control tools, explain the hydrological cycle of a drainage basin.
• AO2 – Application: Apply monsoon dynamics, river‑process terminology, and water‑security concepts to the Sri Lankan context.
• AO3 – Analysis: Interpret incidence vs. rainfall graphs, calculate correlation coefficients, evaluate GIS‑derived risk maps.
• AO4 – Evaluation: Critically assess Sri Lanka’s Integrated Vector Management (IVM) and propose adaptations for a high‑altitude West African country.
• Data‑handling techniques:
  • Graphing monthly malaria incidence against rainfall.
  • Computing Pearson’s r and testing significance (p < 0.05).
  • Using GIS layers (elevation, soil, land‑cover) to produce a vector‑habitat suitability index.
  • Time‑series analysis of case numbers (1990‑2016) to calculate percentage reductions.

6. Key Lessons for Other Countries

• Secure long‑term political commitment and allocate domestic financing.
• Integrate real‑time surveillance with rapid‑response teams to shrink the transmission window.
• Engage communities early; ownership improves net use and reporting of breeding sites.
• Maintain flexibility – rotate insecticides, adopt biological controls when resistance emerges.
• Embed vector‑control safeguards in all development projects (irrigation, housing, road building).
• Target vulnerable groups (children, pregnant women, migrants) to reduce health inequities.

7. Quick Revision Checklist

1. Recall the three AS‑level physical geography topics (atmospheric processes, hydrology & river processes, earth processes) and their specific links to malaria risk.
2. Recall the three AS‑level human geography topics (population & migration, water resources, urban areas) and be able to give quantitative examples (age‑sex structure, water‑use figures, urban‑slum drainage issues).
3. Be able to sketch:
   • The malaria transmission cycle (human‑mosquito‑human).
   • Sri Lanka’s malaria elimination flowchart (surveillance → rapid response → … → monitoring).
4. Memorise the six core components of Sri Lanka’s programme: Integrated Vector Management, Surveillance & Rapid Response, Case Management, Community Engagement, Cross‑Sector Collaboration, Adaptive Monitoring.
5. Practice interpreting the outcome table and calculating percentage reductions in cases and deaths.
6. Prepare a concise evaluation paragraph discussing how the Sri Lankan model could be transferred to a high‑altitude West African setting (e.g., Ethiopia’s highlands).