Extensive low-density Plasmodium falciparum reservoir in the island of Príncipe, an isolated malaria pre-elimination setting.

The isolated Príncipe is at malaria pre-elimination stage. Autochthonous clinical cases have been reported sporadically on the island, signalling the possibility of a sizable subpatent (ie, RDT- and microscopy-negative and PCR-positive) parasite reservoir. Asymptomatic low-density infections were detected by quantitative PCR (qPCR) targeting Plasmodium falciparum multicopy genes (pfr364 and varATS). Positivity rates were assayed for samples surveyed by active case detection (ACD) (n=112) and reactive case detection (RACD) (n=221) in 2022. qPCR unveiled 70% of low parasitemia carriers, reaching >90% in RACD. The high P. falciparum prevalence was confirmed by the two high-sensitivity qPCR protocols. Higher positivity rates were observed in the localities where most malaria cases were reported in 2022. Most parasitemias were very low (<2 Pf /µl). These findings suggest that pre-elimination surveillance can benefit from the routine application of highly sensitive tools to unveil otherwise invisible but potentially relevant parasite populations.

Informations de copyright

Copyright © 2024. Published by Elsevier Ltd.