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neurologyYou need to know

• Diseases can be classified as infectious or non-infectious, communicable or noncommunicable, contagious or non-contagious, and as endemic, epidemic or pandemic according to cause, transmission and spatial scale.
• Infectious diseases are caused by pathogens such as bacteria, viruses, parasites or fungi, whereas non-infectious diseases are not caused by pathogens.
• Communicable diseases can be transmitted between people, animals or the environment, while noncommunicable diseases such as diabetes and cardiovascular disease are not directly transmitted between hosts.
• An endemic disease is constantly present in a particular place, an epidemic is a sudden increase in cases above normal levels, and a pandemic is an epidemic that spreads across several countries or continents.
• Global disease patterns vary: malaria is concentrated mainly in tropical and subtropical regions, HIV has high prevalence in parts of sub-Saharan Africa, tuberculosis is more common where poverty and overcrowding are high, while diabetes and cardiovascular disease are strongly associated with urbanisation, ageing and affluent lifestyles.
• Disease diffusion describes the spread of disease through space over time, and Hägerstrand’s model explains diffusion through stages including initial outbreak, expansion, intensification and later decline or saturation.
• Physical barriers such as mountains, deserts, oceans and remoteness can slow disease diffusion, while socio-economic barriers such as border controls, health systems, vaccination and behaviour change can also alter disease spread.
• Physical factors including temperature, precipitation, relief and water sources influence disease prevalence by affecting pathogen survival, human exposure and the habitats of disease vectors.
• Mosquito-borne diseases are more prevalent in warm, humid environments near standing water because mosquitoes breed in water and survive more successfully in warm climates.
• Seasonal variations such as droughts, monsoon rains and flooding can increase disease outbreaks by altering water availability, sanitation, vector breeding sites and human vulnerability.
• Climate change can increase the range and season length of some vectors, allowing diseases such as West Nile virus, tick-borne diseases and tsetse fly-transmitted diseases to spread to new areas or hosts.
• Zoonotic infectious diseases such as bird flu and rabies spread from animals to humans when human contact with infected animals, vectors or animal products allows pathogens to cross the species barrier.
• Natural hazards such as earthquakes, droughts and monsoon floods can increase disease risk by damaging water supplies, sanitation systems, homes, food security and healthcare access.
• As countries develop economically, communicable diseases usually decline because of better nutrition, clean water, sanitation, vaccination and healthcare, while noncommunicable diseases often rise due to ageing populations and lifestyle changes.
• The epidemiological transition model describes the shift from high mortality caused mainly by infectious diseases and famine to lower mortality dominated by chronic noncommunicable diseases.
• Low-income developing countries often have higher prevalence of diseases of poverty because limited clean water, sanitation, healthcare, nutrition and housing increase susceptibility to communicable disease.
• Advanced countries often have higher prevalence of diseases of affluence because sedentary lifestyles, high-calorie diets, ageing populations, smoking and alcohol consumption increase risks of noncommunicable disease.
• Air pollution increases the incidence of diseases such as lung cancer and bladder cancer because pollutants can damage cells, increase inflammation and expose people to carcinogens over long periods.
• International organisations such as the World Health Organization support disease control by gathering data, predicting outbreaks, coordinating research, issuing guidance, funding programmes and working with governments and agencies.
• Disease eradication means reducing global incidence of a disease to zero through deliberate intervention, and it usually requires effective surveillance, vaccination or treatment, political cooperation, funding and community participation.

• Classify diseases accurately using cause, transmission, contagiousness and scale, for example distinguishing infectious, communicable, contagious, endemic, epidemic and pandemic disease.
• Interpret global disease distribution maps by identifying spatial patterns, clusters, anomalies and links with development, climate, urbanisation or population density.
• Explain disease diffusion using Hägerstrand’s model by describing phases of spread and assessing how physical and socio-economic barriers accelerate or slow transmission.
• Analyse how physical factors such as temperature, precipitation, relief, water sources and seasonality influence vectors, pathogens and human exposure to disease.
• Use a natural hazard case study to explain how environmental and human factors affect disease outbreak, impacts and management strategies at national and international scales.
• Compare the disease profiles of LIDCs, EDCs and ACs by linking economic development to the epidemiological transition and to diseases of poverty and affluence.
• Evaluate a communicable disease case study by assessing causes, prevalence, incidence, spatial patterns, socio-economic impacts and the success of mitigation and response strategies.
• Evaluate a noncommunicable disease case study by assessing social, economic and cultural causes, prevalence, incidence, impacts and the success of mitigation strategies.
• Assess the role of governments, international organisations and NGOs in predicting, mitigating and responding to disease outbreaks at global, national and local scales.
• Evaluate strategies for disease eradication by comparing top-down campaigns, pharmaceutical interventions and bottom-up grassroots education, including the role of women and community participation.