Food systems and the spread of disease

The whole chain from **production → processing → distribution → consumption**, with inputs and outputs at each stage.

**Inputs** = energy, water, labour, seeds, fertiliser put in; **outputs** = food (yield) plus waste and emissions.

The **output ÷ input ratio** — how much food energy you get for the energy you put in.

**Intensive** = high inputs per hectare for high yield; **extensive** = low inputs spread over a large area.

Low-input crops like **cassava** are efficient (high output ÷ input); intensive **beef** and heated greenhouses are not.

It adds **fossil-fuel energy** (tractors, pumps, fertiliser) and cuts **human/animal labour energy**.

Climate change, drought (the Sahel), flooding, pests (fall armyworm) and soil erosion/salinisation.

The spread from the 1960s of **high-yield wheat and rice**, fertiliser and irrigation — e.g. in India — raising output unevenly.

How a new method, seed or technology **spreads** from where it started to other farmers and regions.

**Physical** (climate/water), **economic** (cost/credit), **social** (education/trust) and **political** (government support).

**High energy demand**, expensive set-up, a **limited crop range** (leafy greens) and heavy technology dependence.

Two+ developed factors, a named example (Green Revolution), a weighing of importance, and a clear judgement.

When **all people, at all times, have reliable access** to enough safe, nutritious food for an active, healthy life.

**Unreliable or insufficient access** to enough safe, nutritious food - it can be chronic or sudden.

An **extreme, widespread food shortage** causing mass hunger, malnutrition and a sharp rise in deaths.

**Availability** (enough food), **access** (people can afford and reach it) and **stability** (a reliable supply over time).

**Availability** = is there enough food in the area? **Access** = can people afford and physically reach it?

**Physical/environmental, economic, political and social** factors - and they combine.

It forces farmers off the land, destroys harvests and **blocks roads and aid**, so food cannot be grown or delivered.

Illness such as **HIV/AIDS or malaria** removes adults from the workforce, so fewer can farm and incomes fall.

Low incomes mean families **cannot afford food** when prices rise, so a poor harvest tips them into hunger.

An African belt (Niger, Chad, Mali) with recurring crises: **drought** triggers them, but **poverty, population growth and conflict** turn shortage into famine.

High-yield crops, irrigation and fertiliser in **India** from the 1960s sharply raised output and helped end recurrent famine in Punjab.

Factors from **2+ categories** developed, a **named located example**, a weighing of how they interact, and a clear judgement.

The way a disease **spreads outward across space and through a population** over time.

**Expansion** = the disease stays and ripples outward from its source. **Relocation** = an infected person moves and carries it to a new area.

A disease spread by an organism such as a mosquito — e.g. **malaria** or **dengue**.

A disease spread through contaminated water — e.g. **cholera** or typhoid.

Anything that **slows or blocks** a disease's spread — mountains, dry seasons, clean water, nets, vaccination, quarantine.

A **warm, wet climate** (vectors breed) or **rainfall/flooding** (contaminates water supplies).

**Air travel/migration** (relocation diffusion) or **overcrowding with poor sanitation** (fast person-to-person spread).

**Poverty and weak healthcare** — no money for nets, drugs, clean water or clinics, so the disease is not stopped.

After the 2010 earthquake, cholera was **relocated** in, then spread by **expansion diffusion** through camps with no clean water; tens of thousands died.

Vector-borne by the **Anopheles** mosquito; a warm wet climate gives year-round breeding while **poverty** limits nets and drugs.

**Heavy rain and flooding** mix sewage into wells and rivers, contaminating drinking water again.

A **named disease + place** of the right type, **two+ developed factors**, a **weighing** of relative importance (often over time), and a clear **judgement**.