de Sousa, Taís NóbregaMachado, Patricia CarneiroLopes, InêsDas Neves, EdvaldoNarciso, AldaPires, AnastácioSantos, AdalbertoTrovoada, Maria JesusGil, José PedroLopes, Dinora2024-10-032024-10-032024-101201-9712PURE: 100641369PURE UUID: 405a35fc-4c7a-4e50-9a20-6a73916a6914Scopus: 85203414296PubMed: 39197744http://hdl.handle.net/10362/172976Funding Information: This work was supported by the Swedish Research Council Grant (Grant ref. 200075/2022-5), Conselho Nacional de Desenvolvimento Cient\u00EDfico e Tecnol\u00F3gico (CNPq), and GHTM IHMT. TNS is CNPq Research Productivity fellows. As previously mentioned, the samples were collected as part of the PNEP surveillance activities and were irreversibly anonymized before starting the study, with a new reference assigned. The samples were transferred from S\u00E3o Tom\u00E9 and Pr\u00EDncipe to Lisbon under an MTA signed between the Ministry of Health of S\u00E3o Tom\u00E9 and Pr\u00EDncipe and the Institute of Hygiene and Tropical Medicine. This study was approved by the ethics committee of the IHMT ITQB (ref 16.22). The authors thank all the patients who participated in this study and the S\u00E3o Tom\u00E9 and Pr\u00EDncipe National Malaria Control Program teams for their support in collecting samples and data. Study concept and design: DL and JPG. Statistical and data analysis: TNS, PCM, and IL. Writing the original draft: DL, JPG, and TNS. Project management: DL, JPG, and TNS. Data acquisition: PCM, IL, EV, AN, AP, AS, and MJT. Review of the final manuscript: DL, JPG, TNS, PCM, IL, EV, AN, AP, AS, and MJT. Funding Information: This work was supported by the Swedish Research Council Grant (Grant ref. 200075/2022-5), Conselho Nacional de Desenvolvimento Cient\u00EDfico e Tecnol\u00F3gico (CNPq), and GHTM IHMT. TNS is CNPq Research Productivity fellows. Publisher Copyright: © 2024 The AuthorsObjectives: The isolated Príncipe is at the malaria pre-elimination stage. Autochthonous clinical cases have been reported sporadically on the island, signaling the possibility of a sizable subpatent (i.e., rapid diagnostic test- and microscopy-negative and polymerase chain reaction [PCR]-positive) parasite reservoir. Methods: 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 (n = 112) and reactive case detection (n = 221) in 2022. Results: qPCR unveiled 70% of low parasitemia carriers, reaching >90% in reactive case detection. 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). Conclusions: 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.732085engEliminationMalariaParasite reservoirPlasmodium falciparumMicrobiology (medical)Infectious DiseasesSDG 3 - Good Health and Well-beingjournal article10.1016/j.ijid.2024.107220https://www.scopus.com/pages/publications/85203414296