Background

Selectively targeting and treating malaria-infected individuals may further decrease parasite carriage in low-burden settings. Using a trans-disciplinary approach, a reactive treatment strategy to reduce Plasmodium falciparum prevalence in participating communities was co-developed and tested. Methods: This is a 2-arm, open-label, cluster-randomised trial involving villages in Central Gambia during the 2017 and 2018 malaria transmission season. Villages were randomised in a 1:1 ratio using a minimising algorithm. In the intervention arm, trained village health workers delivered a full course of pre-packed dihydroartemisinin-piperaquine to all residents of compounds where clinical cases were reported while in the control arm, compound residents were screened for infection at the time of the index case reporting. All index cases were treated following national guidelines. The primary endpoint was malaria prevalence, determined by molecular methods, at the end of the intervention period.

Results

The trial was carried out in 50 villages: 34 in 2017 and 16 additional villages in 2018. At the end of the 2018 transmission season, malaria prevalence was 0.8 percent (16/1924, range 0–4 percent) and 1.1 percent (20/1814, range 0–17 percent) in the intervention and control arms, respectively. The odds of malaria infection were 29 percent lower in the intervention than in the control arm after adjustment for age (OR 0.71, 95 percent CI 0.27–1.84, p=0.48). Adherence to treatment was high, with 98 percent (964/979) of those treated completing the 3-day treatment. Over the course of the study, only 37 villages, 20 in the intervention and 17 in the control arm, reported at least one clinical case. The distribution of clinical cases by month in both transmission seasons was similar and the odds of new clinical malaria cases during the trial period did not vary between arms (OR 1.04, 95 percent CI 0.57–1.91, p=0.893). All adverse events were classifed as mild to moderate and resolved completely.

Conclusion

The systematic and timely administration of an anti-malarial treatment to residents of compounds with confrmed malaria cases did not signifcantly decrease malaria prevalence and incidence in communities where malaria prevalence was already low. Treatment coverage and adherence was very high. Results were strongly infuenced by the lower-than-expected malaria prevalence, and by no clinical cases in villages with asymptomatic malaria-infected individuals. 

Published in Malaria Journal 

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Country: The Gambia