From the Guidelines
Rare ring forms of malaria parasites can occasionally be detected in blood smears after treatment has begun, but this doesn't necessarily indicate treatment failure, as evidenced by a study published in 2024 1. If you've completed a full course of antimalarial medication such as artemisinin-based combination therapy (ACT), chloroquine, or atovaquone-proguanil at appropriate doses and still find ring forms in follow-up blood work, continued monitoring is recommended rather than immediate retreatment. These persistent rings may represent dead or dying parasites that haven't been cleared from circulation yet, particularly in the first 1-2 weeks after treatment. However, if fever returns or parasitemia increases, this suggests true treatment failure requiring a different antimalarial regimen, such as dihydroartemisinin-piperaquine (DHAePPQ) or quinine sulphate associated with doxycycline, clindamycin, or mefloquine, as outlined in the treatment guidelines 1. The persistence of ring forms occurs because some antimalarials primarily prevent parasite maturation rather than immediately killing all parasites, and the body needs time to clear these damaged organisms from circulation. Regular follow-up blood smears at 7,14, and 28 days after treatment are ideal to ensure complete parasite clearance, as recommended by the WHO and CDC guidelines, which have been endorsed based on a systematic review and individual data meta-analysis 1. Some key points to consider in the management of malaria include:
- The use of ACTs, such as artemether-lumefantrine (AL), is recommended for the treatment of uncomplicated P. falciparum malaria, with a cure rate of 98.1% reported in a retrospective observational study [@48@].
- The risk of post-artemisinin delayed haemolysis (PADH) should be considered, particularly in patients treated with oral AL, with a reported prevalence of 37.4% on day 14 after treatment [@60@].
- Alternative treatments, such as atovaquone-proguanil, should be used in patients who are contraindicated for ACTs or those coming from areas with high levels of resistance to ACTs [@43@, @44@, @46@]. It is essential to note that the treatment of malaria should be guided by the most recent and highest-quality evidence, and healthcare professionals should consult the latest guidelines and recommendations from reputable sources, such as the WHO and CDC, to ensure optimal patient outcomes.
From the Research
Rare Ring for Malaria after Treatment
- The occurrence of a rare ring for malaria after treatment is not directly addressed in the provided studies 2, 3, 4, 5, 6.
- However, the studies discuss the efficacy and safety of various antimalarial drugs, including artemether-lumefantrine and atovaquone-proguanil, which may be relevant to understanding the treatment of malaria and potential outcomes.
- According to the studies, artemether-lumefantrine is an effective treatment for uncomplicated Plasmodium falciparum malaria, with PCR-corrected 28-day cure rates ranging from 86-100% 5.
- Atovaquone-proguanil is also an effective treatment, but may have higher treatment failure rates in some cases, particularly in areas with high levels of resistance 3.
- The World Health Organization recommends treating uncomplicated cases of malaria with artemisinin combination therapy, except in the first trimester of pregnancy 4.
- Severe malaria is mainly caused by Plasmodium falciparum, and intravenous artesunate is the treatment of choice for severe malaria 4.
- A comparative study of artemether-lumefantrine and atovaquone-proguanil found that travelers with uncomplicated P. falciparum malaria recovered faster on artemether-lumefantrine than on atovaquone-proguanil 6.