Who this is for: Cambridge IGCSE Biology (0610) students who want diseases — pathogens, transmission routes and body defences — to become reliable marks instead of vague “germs make you ill” answers.
What query it owns: how to understand and revise diseases in Cambridge IGCSE Biology.
Why this is safe: this page owns the diseases revision-guide angle, while Tutopiya’s Diseases subtopic page owns the learning resource and the free Diseases quiz owns the practice.

Diseases are conditions that impair the normal functioning of an organism. Cambridge IGCSE Biology (0610) tests whether you can classify pathogens, describe transmission routes, explain how the body defends itself, and distinguish communicable from non-communicable disease. This guide covers the syllabus definitions, the transmission table examiners expect, and the question types that appear every year.

Key takeaways

• A pathogen is a microorganism that causes disease — bacteria, viruses, fungi or protoctists.
• Communicable diseases spread between organisms; non-communicable diseases do not.
• Transmission routes include direct contact, droplets, food/water, vectors and body fluids.
• Physical barriers (skin, mucus, stomach acid) and white blood cells are first-line defences.
• Exam answers must name the pathogen type and the transmission route when asked.

What are diseases in Cambridge IGCSE Biology?

A disease is a disorder of an organism that impairs its normal functioning. Communicable diseases are caused by pathogens and can spread from one organism to another. Non-communicable diseases — such as coronary heart disease or type 2 diabetes — are not caused by pathogens and cannot be transmitted. The syllabus requires you to know specific examples, their pathogens, and how they spread.

You can read the full explanation, worked examples and notes on Tutopiya’s Diseases subtopic page before you attempt questions.

The core ideas you must master

Idea	What it means	How the exam uses it
Pathogen	Microorganism causing disease	”Name the pathogen that causes malaria.”
Communicable	Spread between organisms	”State how cholera is transmitted.”
Non-communicable	Not caused by pathogens	”Give an example of a non-communicable disease.”
Vector	Organism that carries a pathogen	”Explain the role of the mosquito in malaria.”
Body defences	Barriers and white blood cells	”Describe two ways the body prevents infection.”

Pathogens and transmission — syllabus examples

Disease	Pathogen type	Transmission route
Cholera	Bacterium (Vibrio cholerae)	Contaminated food/water
Malaria	Protoctist (Plasmodium)	Vector (female Anopheles mosquito)
HIV/AIDS	Virus	Body fluids (blood, sexual contact)
Tuberculosis (TB)	Bacterium	Airborne droplets
Salmonella food poisoning	Bacterium	Contaminated food

Diseases in past-paper wording: command words that matter

Command word / phrase	What the question wants	Typical diseases stem
Define	Precise syllabus definition	”Define the term pathogen.”
State	Short factual answer	”State how cholera is spread.”
Describe	What happens, step by step	”Describe how the skin acts as a barrier.”
Explain	Cause and effect	”Explain how mosquitoes transmit malaria.”
Suggest	Apply knowledge to a scenario	”Suggest how to reduce spread of cholera.”

Worked exam-style stems (how to answer the wording)

1. “Define the term pathogen.” A pathogen is a microorganism that causes disease. Mark-scheme reward: microorganism + causes disease.
2. “Explain how malaria is transmitted.” The protoctist Plasmodium is carried by the female Anopheles mosquito, which injects the pathogen into the blood when it bites a human. Reward: named pathogen + vector + route.
3. “Describe two ways the body defends itself against pathogens.” Any two from: skin as a physical barrier, mucus trapping pathogens, stomach acid killing bacteria, white blood cells engulfing pathogens (phagocytosis). Reward: named defence + brief mechanism.

When you can recognise the wording instantly, work the full set on the Diseases and Immunity topical past paper questions and the Diseases quiz to lock the definitions in.

How diseases connect to the rest of the syllabus

Diseases sit alongside Immunity (antibodies, vaccination, memory cells). Body defences link to white blood cell structure; transmission links to public health measures. The Cambridge IGCSE Biology resource hub links every Diseases and Immunity subtopic.

Common mistakes students make

• Calling all pathogens “germs” without naming bacteria, virus, fungus or protoctist.
• Confusing communicable with contagious — not all communicable diseases spread easily by contact.
• Saying malaria is caused by a virus (it is a protoctist).
• Omitting the vector when explaining malaria transmission.
• Describing immunity when the question asks only about body defences.

When you need more support

If diseases questions keep costing marks — especially transmission and pathogen-type stems — work through the Diseases and Immunity topical past paper questions and the Diseases quiz, then get focused help from a Cambridge IGCSE Biology tutor.

Frequently asked questions

Is diseases hard in Cambridge IGCSE Biology? The concepts are straightforward, but marks are lost when students confuse pathogen types or omit transmission routes in explain answers.

What is the difference between communicable and non-communicable disease? Communicable diseases are caused by pathogens and can spread between organisms; non-communicable diseases are not caused by pathogens and cannot be transmitted.

What is a vector? A vector is an organism that carries a pathogen from one host to another without necessarily becoming ill itself — for example, the mosquito in malaria.

How do I revise diseases effectively? Read the subtopic notes, learn the transmission table by heart, practise definitions from memory, then take the Diseases quiz.

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