Explain how a pathogen can spread from one person to another through the air.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Communicable diseases can be transmitted between individuals by several different routes. One common route of transmission involves the air.
Model answer (4 marks)
An infected person releases pathogen(s) into the air when coughing, sneezing or speaking.
The pathogen is carried in droplets or aerosols.
The droplets/aerosols are inhaled by another person.
Once inhaled the pathogen infects cells and reproduces inside the new host, causing disease.
The pathogen is carried in droplets or aerosols.
The droplets/aerosols are inhaled by another person.
Once inhaled the pathogen infects cells and reproduces inside the new host, causing disease.
Examiner tips
- Use the word ‘released’ and ‘inhaled’ to show the route. Mention droplets or aerosols. Show the final step of infection and disease. Keep each point short and to the point.
Common mistakes
- Confusing ‘contact’ with ‘air’ transmission. Omitting the inhalation step. Using vague terms like ‘spread’ without specifying droplets/aerosols.
Mark scheme (4 marks)
- An infected person releases pathogen(s) into the air
- Pathogens are carried in droplets / aerosols
- Droplets / pathogens are inhaled by another person
- The pathogen then infects the cells / reproduces inside the new host, causing disease
Key terms in this question
Related
- Revision notes: Communicable diseases →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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