# Influenza is a communicable disease caused by a virus. Explain how the body's non-specific defences prevent the influenza virus from entering and spreading within the body.

> Pearson Edexcel A-Level Biology A (9BI0) — 5.2 Pathogens and infection · Explain · 5 marks

> Influenza (flu) is spread when infected individuals cough or sneeze, releasing virus particles into the air. Every year, thousands of people in the UK are infected.

## Mark scheme (5 marks)

1. Mucus in the airways traps virus particles / pathogens
2. Cilia waft / move mucus (and trapped virus) upward / toward the throat so it can be swallowed or expelled
3. Hydrochloric acid in the stomach kills any swallowed virus / pathogens
4. White blood cells engulf / ingest / destroy pathogens that enter the body by phagocytosis
5. White blood cells also produce antitoxins to neutralise any toxins produced by pathogens / OR skin acts as a physical barrier preventing virus entry

## Key terms

- [communicable disease](https://www.gradenine.co.uk/glossary/communicable-disease)

## Related

- [Revision notes for Pearson Edexcel A-Level Biology A (9BI0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/influenza-is-a-communicable-disease-caused-37e82317) · Published by Druglandscape Ltd.