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. 2020 Oct 12;19(1):366.
doi: 10.1186/s12936-020-03441-z.

High prevalence of asymptomatic malaria infections in adults, Ashanti Region, Ghana, 2018

Melina Heinemann  1   2   3 , Richard O Phillips  4 , Christof D Vinnemeier  2   5 , Christina C Rolling  5   6 , Egbert Tannich  7   8 , Thierry Rolling  9   10   11   12
Affiliations

High prevalence of asymptomatic malaria infections in adults, Ashanti Region, Ghana, 2018

Melina Heinemann et al. Malar J. .

Abstract

Background: Ghana is among the high-burden countries for malaria infections and recently reported a notable increase in malaria cases. While asymptomatic parasitaemia is increasingly recognized as a hurdle for malaria elimination, studies on asymptomatic malaria are scarce, and usually focus on children and on non-falciparum species. The present study aims to assess the prevalence of asymptomatic Plasmodium falciparum and non-falciparum infections in Ghanaian adults in the Ashanti region during the high transmission season.

Methods: Asymptomatic adult residents from five villages in the Ashanti Region, Ghana, were screened for Plasmodium species by rapid diagnostic test (RDT) and polymerase chain reaction (PCR) during the rainy season. Samples tested positive were subtyped using species-specific real-time PCR. For all Plasmodium ovale infections additional sub-species identification was performed.

Results: Molecular prevalence of asymptomatic Plasmodium infection was 284/391 (73%); only 126 (32%) infections were detected by RDT. While 266 (68%) participants were infected with Plasmodium falciparum, 33 (8%) were infected with Plasmodium malariae and 34 (9%) with P. ovale. The sub-species P. ovale curtisi and P. ovale wallikeri were identified to similar proportions. Non-falciparum infections usually presented as mixed infections with P. falciparum.

Conclusions: Most adult residents in the Ghanaian forest zone are asymptomatic Plasmodium carriers. The high Plasmodium prevalence not detected by RDT in adults highlights that malaria eradication efforts must target all members of the population. Beneath Plasmodium falciparum, screening and treatment must also include infections with P. malariae, P. o. curtisi and P. o. wallikeri.

Keywords: Asymptomatic malaria; Ghana; Molecular prevalence; Plasmodium falciparum; Plasmodium malariae; Plasmodium ovale curtisi; Plasmodium ovale wallikeri; Polymerase chain reaction; Rapid diagnostic test; Sub-Saharan Africa.

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Conflict of interest statement

CDV received lecture fees from Bayer AG.

Figures

Fig. 1
Fig. 1
a Location of Asante Akim North (red) in the Ashanti region (outlined in black), Ghana. b Epidemiological map of study communities in Asante Akim North. The figure was created using the R packages ggplot2, maps and raster
Fig. 2
Fig. 2
Prevalence of Plasmodium infection detectable by PCR among (a) women and (b) men of different age groups. Pf, Plasmodium falciparum; Pm, Plasmodium malariae; Po, Plasmodium ovale
Fig. 3
Fig. 3
PCR Ct values according to RDT result for a Plasmodium species infection and b P. falciparum monoinfection. Red lines indicate median values. Ct, cycle threshold; P., Plasmodium; RDT, rapid diagnostic test
See this image and copyright information in PMC

References

    1. WHO . World malaria report 2019. Geneva: World Health Organization; 2019.
    1. Cook J, Xu W, Msellem M, Vonk M, Bergstrom B, Gosling R, et al. Mass screening and treatment on the basis of results of a Plasmodium falciparum-specific rapid diagnostic test did not reduce malaria incidence in Zanzibar. J Infect Dis. 2015;211:1476–1483. doi: 10.1093/infdis/jiu655. - DOI - PMC - PubMed
    1. Bousema T, Okell L, Felger I, Drakeley C. Asymptomatic malaria infections: detectability, transmissibility and public health relevance. Nat Rev Microbiol. 2014;12:833–840. doi: 10.1038/nrmicro3364. - DOI - PubMed
    1. Andrews L, Andersen RF, Webster D, Dunachie S, Walther RM, Bejon P, et al. Quantitative real-time polymerase chain reaction for malaria diagnosis and its use in malaria vaccine clinical trials. Am J Trop Med Hyg. 2005;73:191–198. doi: 10.4269/ajtmh.2005.73.191. - DOI - PubMed
    1. Laishram DD, Sutton PL, Nanda N, Sharma VL, Sobti RC, Carlton JM, et al. The complexities of malaria disease manifestations with a focus on asymptomatic malaria. Malar J. 2012;11:29. doi: 10.1186/1475-2875-11-29. - DOI - PMC - PubMed