Artemisinin derivatives clear most falciparum parasites quickly, and in a sensitive infection very few patients remain smear-positive on day 3 of treatment. Persistent parasitaemia on day 3 is the standard clinical marker used to detect artemisinin partial resistance.
A repeat blood smear on day 3 costs little, catches slow clearers who need closer follow-up, and contributes to national surveillance. Fever on day 3 is a less reliable guide than the smear.
- Repeat a thick and thin smear on day 3 after starting treatment for falciparum malaria.
- Record parasite density, not just positive or negative.
- A positive day-3 smear calls for closer follow-up and checking that the full course is taken.
- Report persistent parasitaemia to the malaria programme.
- Follow-up to day 28 is what detects true treatment failure.
Why it matters
Partial resistance is invisible unless someone looks on day 3.
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