Variation of prevalence of malaria, parasite density and the multiplicity of Plasmodium falciparum infection throughout the year at three different health centers in Brazzaville, Republic of Congo

Mayengue, Pembé Issamou; Batsimba, Dezi Kouhounina; Niama, Roch Fabien; Ottia, Reyna Ibara; Malonga-Massanga, Alida; Fila-Fila, Grâce Petula Urielle; Ahombo, Gabriel; Kobawila, Simon Charles; Parra, Henri Joseph

doi:10.1186/s12879-020-4913-3

Cited by 18 publications

(13 citation statements)

References 26 publications

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“…The studies in Ghana were actually carried out on asymptomatic populations with increased MOI values compared to symptomatic populations on whom the present work is based. Unlike this study, no seasonal fluctuation of the MOI was reported in the Democratic Republic of the Congo [ 38 ] highlighting the geographical differences in the expression of the MOI. That is probably why the MOI is not a reliable indicator of malaria transmission in areas with reduced intensity of malaria transmission [ 37 ].…”

Section: Discussioncontrasting

confidence: 83%

Determinants of Plasmodium falciparum multiplicity of infection and genetic diversity in Burkina Faso

et al. 2020

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Background Investigating malaria transmission dynamics is essential to inform policy decision making. Whether multiplicity of infection (MOI) dynamic from individual infections could be a reliable malaria metric in high transmission settings with marked variation in seasons of malaria transmission has been poorly assessed. This study aimed at investigating factors driving Plasmodium falciparum MOI and genetic diversity in a hyperendemic area of Burkina Faso. Methods Blood samples collected from a pharmacovigilance trial were used for polymerase chain reaction genotyping of the merozoite surface proteins 1 and 2. MOI was defined as the number of distinct parasite genotypes co-existing within a particular infection. Monthly rainfall data were obtained from satellite data of the Global Precipitation Measurement Database while monthly malaria incidence aggregated data were extracted from District Health Information Software 2 medical data of the Center-West health regional direction. Results In the study area, infected people harboured an average of 2.732 (± 0.056) different parasite genotypes. A significant correlation between the monthly MOI and the monthly malaria incidence was observed, suggesting that MOI could be a good predictor of transmission intensity. A strong effect of season on MOI was observed, with infected patients harbouring higher number of parasite genotypes during the rainy season as compared to the dry season. There was a negative relationship between MOI and host age. In addition, MOI decreased with increasing parasite densities, suggesting that there was a within-host competition among co-infecting genetically distinct P. falciparum variants. Each allelic family of the msp1 and msp2 genes was present all year round with no significant monthly fluctuation. Conclusions In high malaria endemic settings with marked variation in seasons of malaria transmission, MOI represents an appropriate malaria metric which provides useful information about the longitudinal changes in malaria transmission in a given area. Besides transmission season, patient age and parasite density are important factors to consider for better understanding of variations in MOI. All allelic families of msp1 and msp2 genes were found in both dry and rainy season. The approach offers the opportunity of translating genotyping data into relevant epidemiological information for malaria control.

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Section: Discussioncontrasting

confidence: 83%

Determinants of Plasmodium falciparum multiplicity of infection and genetic diversity in Burkina Faso

et al. 2020

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“…The predominant alleles were K1-type alleles for msp-1 and FC27-type alleles for msp-2 . These findings are consistent with previous reports for Madagascar [ 14 ] and other settings in Africa (Nigeria [ 18 , 26 ], Congo Brazzaville [ 29 ], Mauritania [ 30 ], Benin [ 31 ], Gabon [ 32 , 33 ], Ivory Coast [ 34 ], Cameroon, [ 35 ], Ethiopia [ 36 – 39 ]), India [ 40 ], and Southeast Asia [ 41 ]. However, they contrast with recent reports from Myanmar [ 42 ], where MAD20 and 3D7 were the most prevalent alleles.…”

Section: Discussionsupporting

confidence: 92%

Genetic diversity of Plasmodium falciparum populations in three malaria transmission settings in Madagascar

Ralinoro

Rakotomanga

Rakotosaona

et al. 2021

Malar J

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Background Assessment of the genetic diversity of Plasmodium falciparum parasites from various malaria transmission settings could help to define tailored local strategies for malaria control and elimination. Such assessments are currently scarce in Madagascar. The study presented here aimed to bridge this gap by investigating the genetic diversity of P. falciparum populations in three epidemiological strata (Equatorial, Tropical and Fringes) in Madagascar. Methods Two-hundred and sixty-six P. falciparum isolates were obtained from patients with uncomplicated malaria enrolled in clinical drug efficacy studies conducted at health centres in Tsaratanana (Equatorial stratum), Antanimbary (Tropical stratum) and Anjoma Ramartina (Fringes) in 2013 and 2016. Parasite DNA was extracted from blood samples collected before anti-malarial treatment. Plasmodium species were identified by nested PCR targeting the 18 S rRNA gene. The genetic profiles of P. falciparum parasites were defined by allele-specific nested PCR on the polymorphic regions of the msp-1 and msp-2 genes. Results Fifty-eight alleles were detected in the P. falciparum samples tested: 18 alleles for msp-1 and 40 for msp-2. K1 (62.9%, 139/221) and FC27 (69.5%, 114/164) were the principal msp-1 and msp-2 allele families detected, although the proportions of the msp-1 and msp-2 alleles varied significantly between sites. Polyclonal infections were more frequent at sites in the Equatorial stratum (69.8%) than at sites in the Tropical stratum (60.5%) or Fringes (58.1%). Population genetics analyses showed that genetic diversity was similar between sites and that parasite flow within sites was limited. Conclusions This study provides recent information about the genetic diversity of P. falciparum populations in three transmission strata in Madagascar, and valuable baseline data for further evaluation of the impact of the control measures implemented in Madagascar.

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“…The high prevalence of false negative RDT results recorded by both the UsmRDT and the mRDT could have been due to the presence of low parasite densities, below their respective lower limit of detection. Low-density parasites are prevalent in asymptomatic parasite carriers during the off-peak malaria season [ 46 ]. The presence of parasites with pfhrp 2 gene deletions could also result in false negative RDT results [ 47 – 49 ].…”

Section: Discussionmentioning

confidence: 99%

Diagnostic performance of an ultrasensitive HRP2-based malaria rapid diagnostic test kit used in surveys of afebrile people living in Southern Ghana

Acquah

Donu

Obboh

et al. 2021

Malar J

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Background The Alere™ Malaria Ag P.f Ultra-sensitive RDT (UsmRDT) kit is an HRP2-based malaria rapid diagnostic test (RDT) with enhanced sensitivity relative to the SD Bioline Malaria Ag P.f RDT (mRDT) kit. However, the diagnostic performance of the UsmRDT kit has not been evaluated in Ghana. Methods A total of 740 afebrile participants aged between 3 and 88 years old were recruited from the Central and Greater Accra Regions of Ghana during the off-peak malaria season. Axillary body temperature was measured, and a volume of 1 ml venous blood was drawn from each participant. Prior to separating the blood into plasma and packed cell pellets via centrifugation, the blood was spotted onto one UsmRDT and one mRDT kit and also used to prepare thick and thin blood smears as well as filter paper blood spots. Plasmodium falciparum specific polymerase chain reaction (PCR) was performed on gDNA extracted from 100 µl of the whole blood. Results The overall positivity rate for microscopy, PCR, UsmRDT and mRDT kit were 20.4%, 40.8%, 31.3% and 30.8%, respectively. Overall, the UsmRDT identified 9.3% (28/302) more PCR positive samples than the mRDT kits. All samples that were negative by the UsmRDT kit were also negative by the mRDT kit. Overall, the sensitivity and specificity of the UsmRDT was 73% (221/302) and 89% (388/436), respectively, while that for the mRDT kit was 58% and 90%, respectively. Conclusion Although the UsmRDT kit was not as sensitive as PCR at detecting asymptomatic P. falciparum carriage, it correctly identified P. falciparum in 9.3% of the study participants that were not captured by the mRDT kit. In malaria endemic settings, the UsmRDT would provide an added advantage by identifying more asymptomatic P. falciparum carriers than the mRDT kit for targeted treatment interventions.

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Variation of prevalence of malaria, parasite density and the multiplicity of Plasmodium falciparum infection throughout the year at three different health centers in Brazzaville, Republic of Congo

Cited by 18 publications

References 26 publications

Determinants of Plasmodium falciparum multiplicity of infection and genetic diversity in Burkina Faso

Determinants of Plasmodium falciparum multiplicity of infection and genetic diversity in Burkina Faso

Genetic diversity of Plasmodium falciparum populations in three malaria transmission settings in Madagascar

Diagnostic performance of an ultrasensitive HRP2-based malaria rapid diagnostic test kit used in surveys of afebrile people living in Southern Ghana

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