Disease Dilemmas - Geographical Debates Options

These flashcards cover disease classification, patterns of distribution, diffusion models, physical/human drivers of disease, the epidemiological transition model, and global mitigation strategies.

How are infectious diseases spread?

They are spread by pathogens such as bacteria, viruses, and parasites, such as malaria.

What characterizes a non-communicable disease?

They are not spread from person to person but have causes related to lifestyle (e.g., heart disease), nutritional deficiencies (e.g., rickets), or genetic inheritance.

What is the difference between an epidemic and a pandemic?

An epidemic is a disease outbreak that attacks many people at the same time in a restricted geographical area, whereas a pandemic is an epidemic that spreads globally.

What are zoonotic diseases?

Infectious diseases transmitted from animals to humans, such as rabies or the plague.

Define 'disease diffusion'.

The process by which a disease spreads outwards beyond its geographical source.

What is expansion diffusion?

A type of diffusion where the disease has a source and spreads outwards into new areas while the source area remains infected.

What is hierarchical diffusion?

When a disease spreads through a structured sequence of locations, usually from large, well-connected centres to smaller, more isolated centres.

In Hägerstrand’s diffusion model, what is the 'neighbourhood effect'?

The probability of contact between those infected and those not infected, influenced by distance decay.

What shape represents the number of people infected over time in Hägerstrand’s model?

An S-shaped logistic curve.

What are the four phases of diffusion in Hägerstrand’s model?

1. Primary stage, 2. Diffusion stage, 3. Condensing stage, 4. Saturation stage.

Give examples of physical and socio-economic barriers to disease diffusion.

Physical barriers include distance, mountains, seas, deserts, and climate; socio-economic barriers include political border checks, curfews, or quarantining.

How do temperature and humidity affect malaria vectors?

Mosquitoes are particularly active in average temperatures between $18^{\circ}C$ and $40^{\circ}C$ and where average monthly relative humidity is over $60\%$.

Which seasons see peaks in influenza and respiratory illness in the Northern Hemisphere?

The winter months.

How is climate change predicted to affect sleeping sickness (trypanosomiasis) by 2090?

The WHO predicts it will spread to southern Africa and affect $77 \times 10^{6}$ people as temperatures rise.

What conditions increase the probability of zoonotic disease spread?

Free movement of infected animals, urbanization creating animal habitats, lack of effective vaccination for pets/livestock, poor hygiene/sanitation, and prolonged close human-animal contact.

What is the Epidemiological Transition Model?

A model put forward by Abdel Omran in 1971 suggesting that as a country develops, there is a transition from infectious diseases to chronic and degenerative diseases as the main cause of death.

Describe the three contexts Omran identified for the epidemiological transition model.

1. Classical/western model (slow death rate decline followed by lower fertility); 2. Accelerated model (rapid falls in mortality); 3. Contemporary/delayed model (mortality decreases not accompanied by fertility decline).

What are the characteristics of the 'Age of infection and famine' stage?

Life expectancy of $20\text{--}40$ years, poor sanitation, unreliable food supply, and mortality caused by infections and nutritional deficiencies.

What characterizes the 'Age of delayed degenerative diseases' phase?

Life expectancy of around $70+$ years, where treatment extends life for those with heart disease and cancer, and dementia/ageing diseases appear.

What are the primary functions of the World Health Organization (WHO)?

Data collection, providing leadership in health matters, technical support, research, monitoring, and responding to major disease outbreaks.

What is the 'distance decay' concept in disease mitigation?

The principle that the further a place is from the source of a disease, the lower the incidence of that disease.

What were the two main aims of the 2007 strategic action plan for H5N1 avian flu?

Preventing the emergence and/or spread of a pandemic virus and preparing all countries to cope with a pandemic.

Which drug is derived from the dried bark of cinchonas and used to treat malaria?

Quinine, which requires average temperatures above $20^{\circ}C$ and humid conditions.

What are the growing conditions required for the opium poppy (source of Morphine)?

Warm, humid conditions with temperatures between $30^{\circ}C$ and $38^{\circ}C$.

Why is Guinea worm (Dracunculiasis) prioritized for eradication?

Diagnosis is easy (visual recognition), the intermediate host is restricted to stagnant water, interventions are simple/cost-effective, and it has a limited geographical distribution.

What is 'biopiracy' in the context of medicinal plants?

When medical drugs from wild environments are exploited by pharmaceutical companies with little or no benefit to indigenous people.

What are grassroots strategies in health?

Small, community-based projects focusing on the needs of people, often favored by NGOs like Oxfam, involving education and engagement of local people.

Why do female frontline health workers often have a greater impact on vaccination programs?

They can relate to women more effectively, they are often primary carers, and they understand specific female roles (like sourcing water) that can influence disease spread.