Malaria and CHD case study

Malaria introduction

• Malaria → a life-threatening disease caused by parasite transmitted to humans through the bite of infected female Anopheles mosquitoes.

• Symptoms → high fever, chills, headaches, vomiting, and, in severe cases, organ failure or death.

• At risk populations → children under five, pregnant women, and immunocompromised individuals in endemic regions (the disease is consistently present but limited to a particular region).

Global prevalence and distribution

• 3.6 billion people (nearly half the world’s population) lived in areas at risk of malaria transmission – WHO 2018.

• Children under five years of age are the most vulnerable group – accounted for 67% of all malaria deaths worldwide – WHO 2018.

• Sub-Saharan Africa account for 93% of malaria cases and 94% of malaria deaths.

• 6 countries accounted for more than half of all malaria cases worldwide – Nigeria 25%, DRC 12%, Uganda 5%.

• Southeast Asia, Latin America, and parts of the Middle East also report cases.

Seasonal incidence and link to physical environments

• Seasons → mosquitoes breed in stagnant water and transmission is greatest in areas during the rainy season.

• Geography → altitudes above 1500 m and where rainfall is below 1000 mm, malaria transmissions fall.

• Temperatures → parasites require temperatures of between 16°C and 32°C to develop inside the mosquito – one reason for why it’s largely concentrated in the tropics and subtropics.

• Climate change → may gradually alters patterns of transmission seasons as more areas experience flood events and higher temperatures.

• Land use determines malaria risk → studies show people in India living in proximity to forested areas are more susceptible to infection – due to higher humidity.

Link to socio-economic environments

• Poverty → poor populations lack access to healthcare, insecticide-treated nets, and preventative treatments.

• Economic impacts → malaria reduces workforce productivity and tourisms and FDI in endemic regions are negatively affected.

• Densely populated areas → clustered built-up areas and overcrowded rooms increase the risk of spread.

• Unsanitary conditions → malaria ‘hotspots’ in Chennai shows houses were surrounded by polluted waste outflows – open defecation commonly attract mosquitoes.

• Occupation → agricultural workers work outdoors at peak mosquito activity times, increasing exposure

Impacts of environmental variables on transmission vectors

• Temperature → warmer climates accelerate mosquito life cycles and parasite development within mosquitoes.

• Rainfall → heavy rainfall creates breeding pools, but excessive flooding can wash away larvae.

• Seasonality → transmission peaks during rainy seasons, with reduced risk in drier periods.

• Humidity → high humidity prolong mosquito survival, increasing transmission potential.

Impact on health and wellbeing

• Health → causes 400,000+ deaths annually, with severe impacts on children under 5 – leads to long-term complications like anaemia, developmental delays, and organ damage.

• Social wellbeing → emotional stress for families due to illness and death. Also has long-term consequences e.g., cognitive impairment and anaemia.

• Economic wellbeing → reduces productivity and income due to missed work and school. Increases healthcare costs for families and governments.

• People who have lived for years in areas with malaria may develop a partial immunity to new infections.

Management strategies

• Diagnosis and treatment → diagnostic tests (RDTs) for early detection – antimalarial drugs like artemisinin-based combination therapies (ACTs) for treatment.

• Vector control → insecticide-treated nets (ITNs) to prevent bites during sleep – indoor residual spraying (IRS) with insecticides to kill mosquitoes.

• Health education → awareness campaigns to promote preventative measures like nets and seeking prompt treatment.

• Mosquito coils → coils are burned, releasing smoke to control mosquito invasion – studies show only between 24-64% effective.

  • While cases have declined due to control efforts, resurgence is possible due to drug resistance and changes in vector behaviour.

Mitigation strategies

• Environmental management → draining stagnant water, filling ditches, and removing mosquito breeding grounds – proper irrigation practices to reduce standing water.

• Vaccination → the RTS malaria vaccine is being rolled out in endemic regions, offering partial protection.

• Global funding and partnerships → organisations like WHO, the Global Fund, and Roll Back Malaria work to provide resources for prevention and treatment in endemic areas.

• Climate change → addressing climate change to reduce expanding mosquito habitats in previously unaffected regions.

Coronary heart disease introduction

• CHD → when the heart's blood supply is blocked by a build-up of fatty substances in the coronary arteries.

• Symptoms → chest pain (angina), shortness of breath, fatigue, and in severe cases, heart attacks.

• At risk populations → older adults, individuals with unhealthy lifestyles, and those with a family history of heart disease.

Global prevalence and distribution

• CHD is a leading cause of death worldwide, particularly in HICs – 30% of US population is obese, increasing risk of CHD.

• Prevalence is rising in low and middle-income countries – due to urbanisation, lifestyle changes, and increased risk factors like obesity.

• Death rates are decreasing in some HIC’s due to improved healthcare and awareness – WHO data shows disparities in CHD prevalence due to healthcare access and lifestyle factors.

Link to physical environments

• Air pollution → exposure to fine particulate matter (PM 2.5) increases the risk of CHD by causing inflammation and oxidative stress.

• Access to green spaces → lack of green spaces reduces opportunities for physical activity, contributing to sedentary lifestyles and increased risk.

• Climate and weather → extreme temperatures (cold or hot) can trigger heart attacks in vulnerable individuals, exacerbating cardiovascular stress.

Link to socio-economic environments

• Poverty → low-income populations may have limited access to healthy food, healthcare, and recreational facilities, increasing risk factors like obesity and hypertension.

• Healthcare access → inadequate access to preventive care, early diagnosis, and treatment in low-income regions worsens outcomes.

• Urbanisation → urban lifestyles often involve unhealthy diets, reduced physical activity, and increased pollution exposure – all contributing to CHD.

• High blood pressure → 47% of heart attacks worldwide are attributed to hypertension – the heart has to worker harder and the extra strain narrows the coronary arteries.

• Family history → first degree relatives of patients with premature CHD are at increased risk of developing the disease themselves.

• Ethnicity → racial and ethnic backgrounds influence CHD risk – genetic predisposition to salt sensitivity results in African Americans being more susceptible to high blood pressure in the US.

Impact of lifestyles on the disease

• Tobacco use → 20,000 CHD deaths each year can be attributed to smoking – blood is more likely to clot, blocking blood flow to the heart and brain.

• Stress → chronic stress increases cortisol levels, leading to high blood pressure and unhealthy behaviours.

• Physical inactivity → sedentary lifestyles reduce cardiovascular fitness and increase obesity rates.

Impact on health and wellbeing

• Social impacts → emotional toll on families and caregivers, including stress and reduced quality of life.

• Economic impacts → loss of productivity and income due to illness or premature death – high treatment costs for patients and healthcare systems.

• Governments → pressure and strain on governments with the cost of healthcare provision and medication.

• Surgery risk → those who suffer from heart attacks can undergo heart bypass surgery to reduce the risk – but can be stressful and risky.

• Confidence loss → those suffering from heart attacks can lose confidence in doing physical activity – rehabilitation programmes offered for those on recovery.

Management strategies

• Lifestyle changes → adopting heart-healthy diets e.g., Mediterranean diet, regular physical activity or quitting unhealthy habits e.g., smoking.

• Medical management → medications to lower cholesterol e.g., statins, or advanced treatments like stents or pacemakers for severe cases – governments ensure they’re affordable to increase accessibility to all of the population.

Mitigation strategies

• Public health campaigns → promoting healthy diets and physical activity.

• Urban planning → increasing access to green spaces to encourage active transport e.g., walking or cycling.

• Routine health screenings → early detection of risk factors like high blood pressure, cholesterol and obesity.

• School meals → ensure children receive healthy balanced meals.