Opportunistic infection

Definition

An infection that takes advantage of a weakened immune system and would normally be controlled more effectively.

Used by Edexcel and OCR

Specification 5.3 · Paper 1

The person is then more susceptible to opportunistic infections, such as pneumonia, caused by pathogens that take advantage of the weakened immune system.
Revise: Disease Susceptibility

Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)

An infection that causes illness mainly when a person’s immune defences are weakened.

1
When using HIV as an example, identify the mechanism: fewer lymphocytes weaken the immune response, allowing opportunistic infections to develop more easily.

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As immune function declines, pathogens that would normally be controlled can cause serious opportunistic infections, such as pneumonia.