# Explain why a person who is infected with a pathogen may not show symptoms of disease immediately.

> Eduqas GCSE Biology — 2.6.1 Pathogens and disease · Explain · 4 marks

## Mark scheme (4 marks)

1. There is an incubation period after infection
2. The pathogen must multiply / reproduce inside the body
3. Symptoms only appear once the number of pathogens (or toxins produced) reaches a sufficient level
4. During the incubation period the infected person can still spread the pathogen to others / is contagious without knowing

## Key terms

- [pathogen](https://www.gradenine.co.uk/glossary/pathogen)
- [symptoms](https://www.gradenine.co.uk/glossary/symptoms)

## Related

- [Revision notes for Eduqas GCSE Biology](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/explain-why-a-person-who-is-6a33ee7a) · Published by Druglandscape Ltd.