Malaria parasite species composition of Plasmodium infections among asymptomatic and symptomatic school-age children in rural and urban areas of Kinshasa, Democratic Republic of Congo
Abstract:Background
Malaria remains a major public health concern in the Democratic Republic of Congo (DRC), and school-age children are relatively neglected in malaria prevalence surveys and may constitute a significant reservoir of transmission. This study aimed to understand the burden of malaria infections in school-age children in Kinshasa/DRC.
Methods
A total of 634 (427 asymptomatic and 207 symptomatic) blood samples collected from school-age childre… Show more
“…Samples used in this study were collected from a previous cross-sectional survey carried out in October and November 2019 among school-age children with ages ranging between 6 and 14 years in Mont-Ngafula-2 rural health zone (HZ) and Selembao urban HZ of Kinshasa, Democratic Republic of Congo (Fig. 1 ) [ 26 ]. Fig.…”
Section: Methodsmentioning
confidence: 99%
“…DNA were extracted and kept at − 80 °C until use. Nested-PCR targeting the Plasmodium mitochondrial cytochrome c oxidase III (Cox3) gene was performed for identification of Plasmodium species (266 asymptomatic and 196 symptomatic samples were analysed) as described in a previous report [ 26 ]. Asymptomatic schoolchildren not showing fever and/or malaria-related symptoms, including headache, chills, body joint pains, fatigue, 2 weeks prior to the survey were recruited from schools.…”
Section: Methodsmentioning
confidence: 99%
“…Symptomatic children were recruited from health facilities and were outpatients seeking healthcare due to fever or/and malaria-related symptoms within 72 h prior to the survey. Schoolchildren whose parents or relatives signed written consent forms were included in this study [ 26 ]. Four hundred and sixty-two positive DNA samples (210 microscopy negative, 252 microscopy positive and 157 Pf HRP2 RDT negative, 305 Pf HRP2 RDT positive) were used in this study for assessment of pfhrp 2/3 gene deletions.…”
Section: Methodsmentioning
confidence: 99%
“…Pfhrp2 and pfhrp3 PCR genotyping was performed as previously described [ 26 ], with minor modifications using conventional single step PCR with primers targeting exon 2 of the genes. Selected samples were used to amplified pfhrp2 PCR using One Taq 2× Master Mix with standard buffer, DNA template (3 μL), 400 nM of forward primer (5′-CAAAAGGACTTAATTTAAATAAGAG-3′), 400 nM reverse primer (5′-AATAAATTTAATGGCGTAGGCA-3′) in a 25 µL final volume.…”
Section: Methodsmentioning
confidence: 99%
“…A previous survey conducted in 2011, that included 133 asymptomatic children in the Mont-Ngafula-2 health zone (HZ) and 145 asymptomatic children in the Selembao HZ aged 6–59 months found a prevalence of 35% and 27%, respectively, when tested by RDT [ 25 ]. A study conducted in the same two areas in 2019 and including 427 asymptomatic and 207 symptomatic school-aged children aged 6–14 years found 41% (Mont-Ngafula-2: 56%; Selembao: 28%) and 64% (Mont-Ngafula-2: 66%; Selembao: 63%) of malaria prevalence by RDT, respectively [ 26 ].…”
Background
Loss of efficacy of diagnostic tests may lead to untreated or mistreated malaria cases, compromising case management and control. There is an increasing reliance on rapid diagnostic tests (RDTs) for malaria diagnosis, with the most widely used of these targeting the Plasmodium falciparum histidine-rich protein 2 (PfHRP2). There are numerous reports of the deletion of this gene in P. falciparum parasites in some populations, rendering them undetectable by PfHRP2 RDTs. The aim of this study was to identify P. falciparum parasites lacking the P. falciparum histidine rich protein 2 and 3 genes (pfhrp2/3) isolated from asymptomatic and symptomatic school-age children in Kinshasa, Democratic Republic of Congo.
Methods
The performance of PfHRP2-based RDTs in comparison to microscopy and PCR was assessed using blood samples collected and spotted on Whatman 903™ filter papers between October and November 2019 from school-age children aged 6–14 years. PCR was then used to identify parasite isolates lacking pfhrp2/3 genes.
Results
Among asymptomatic malaria carriers (N = 266), 49%, 65%, and 70% were microscopy, PfHRP2_RDT, and pfldh-qPCR positive, respectively. The sensitivity and specificity of RDTs compared to PCR were 80% and 70% while the sensitivity and specificity of RDTs compared to microscopy were 92% and 60%, respectively. Among symptomatic malaria carriers (N = 196), 62%, 67%, and 87% were microscopy, PfHRP2-based RDT, pfldh-qPCR and positive, respectively. The sensitivity and specificity of RDTs compared to PCR were 75% and 88%, whereas the sensitivity and specificity of RDTs compared to microscopy were 93% and 77%, respectively. Of 173 samples with sufficient DNA for PCR amplification of pfhrp2/3, deletions of pfhrp2 and pfhrp3 were identified in 2% and 1%, respectively. Three (4%) of samples harboured deletions of the pfhrp2 gene in asymptomatic parasite carriers and one (1%) isolate lacked the pfhrp3 gene among symptomatic parasite carriers in the RDT positive subgroup. No parasites lacking the pfhrp2/3 genes were found in the RDT negative subgroup.
Conclusion
Plasmodium falciparum histidine-rich protein 2/3 gene deletions are uncommon in the surveyed population, and do not result in diagnostic failure. The use of rigorous PCR methods to identify pfhrp2/3 gene deletions is encouraged in order to minimize the overestimation of their prevalence.
“…Samples used in this study were collected from a previous cross-sectional survey carried out in October and November 2019 among school-age children with ages ranging between 6 and 14 years in Mont-Ngafula-2 rural health zone (HZ) and Selembao urban HZ of Kinshasa, Democratic Republic of Congo (Fig. 1 ) [ 26 ]. Fig.…”
Section: Methodsmentioning
confidence: 99%
“…DNA were extracted and kept at − 80 °C until use. Nested-PCR targeting the Plasmodium mitochondrial cytochrome c oxidase III (Cox3) gene was performed for identification of Plasmodium species (266 asymptomatic and 196 symptomatic samples were analysed) as described in a previous report [ 26 ]. Asymptomatic schoolchildren not showing fever and/or malaria-related symptoms, including headache, chills, body joint pains, fatigue, 2 weeks prior to the survey were recruited from schools.…”
Section: Methodsmentioning
confidence: 99%
“…Symptomatic children were recruited from health facilities and were outpatients seeking healthcare due to fever or/and malaria-related symptoms within 72 h prior to the survey. Schoolchildren whose parents or relatives signed written consent forms were included in this study [ 26 ]. Four hundred and sixty-two positive DNA samples (210 microscopy negative, 252 microscopy positive and 157 Pf HRP2 RDT negative, 305 Pf HRP2 RDT positive) were used in this study for assessment of pfhrp 2/3 gene deletions.…”
Section: Methodsmentioning
confidence: 99%
“…Pfhrp2 and pfhrp3 PCR genotyping was performed as previously described [ 26 ], with minor modifications using conventional single step PCR with primers targeting exon 2 of the genes. Selected samples were used to amplified pfhrp2 PCR using One Taq 2× Master Mix with standard buffer, DNA template (3 μL), 400 nM of forward primer (5′-CAAAAGGACTTAATTTAAATAAGAG-3′), 400 nM reverse primer (5′-AATAAATTTAATGGCGTAGGCA-3′) in a 25 µL final volume.…”
Section: Methodsmentioning
confidence: 99%
“…A previous survey conducted in 2011, that included 133 asymptomatic children in the Mont-Ngafula-2 health zone (HZ) and 145 asymptomatic children in the Selembao HZ aged 6–59 months found a prevalence of 35% and 27%, respectively, when tested by RDT [ 25 ]. A study conducted in the same two areas in 2019 and including 427 asymptomatic and 207 symptomatic school-aged children aged 6–14 years found 41% (Mont-Ngafula-2: 56%; Selembao: 28%) and 64% (Mont-Ngafula-2: 66%; Selembao: 63%) of malaria prevalence by RDT, respectively [ 26 ].…”
Background
Loss of efficacy of diagnostic tests may lead to untreated or mistreated malaria cases, compromising case management and control. There is an increasing reliance on rapid diagnostic tests (RDTs) for malaria diagnosis, with the most widely used of these targeting the Plasmodium falciparum histidine-rich protein 2 (PfHRP2). There are numerous reports of the deletion of this gene in P. falciparum parasites in some populations, rendering them undetectable by PfHRP2 RDTs. The aim of this study was to identify P. falciparum parasites lacking the P. falciparum histidine rich protein 2 and 3 genes (pfhrp2/3) isolated from asymptomatic and symptomatic school-age children in Kinshasa, Democratic Republic of Congo.
Methods
The performance of PfHRP2-based RDTs in comparison to microscopy and PCR was assessed using blood samples collected and spotted on Whatman 903™ filter papers between October and November 2019 from school-age children aged 6–14 years. PCR was then used to identify parasite isolates lacking pfhrp2/3 genes.
Results
Among asymptomatic malaria carriers (N = 266), 49%, 65%, and 70% were microscopy, PfHRP2_RDT, and pfldh-qPCR positive, respectively. The sensitivity and specificity of RDTs compared to PCR were 80% and 70% while the sensitivity and specificity of RDTs compared to microscopy were 92% and 60%, respectively. Among symptomatic malaria carriers (N = 196), 62%, 67%, and 87% were microscopy, PfHRP2-based RDT, pfldh-qPCR and positive, respectively. The sensitivity and specificity of RDTs compared to PCR were 75% and 88%, whereas the sensitivity and specificity of RDTs compared to microscopy were 93% and 77%, respectively. Of 173 samples with sufficient DNA for PCR amplification of pfhrp2/3, deletions of pfhrp2 and pfhrp3 were identified in 2% and 1%, respectively. Three (4%) of samples harboured deletions of the pfhrp2 gene in asymptomatic parasite carriers and one (1%) isolate lacked the pfhrp3 gene among symptomatic parasite carriers in the RDT positive subgroup. No parasites lacking the pfhrp2/3 genes were found in the RDT negative subgroup.
Conclusion
Plasmodium falciparum histidine-rich protein 2/3 gene deletions are uncommon in the surveyed population, and do not result in diagnostic failure. The use of rigorous PCR methods to identify pfhrp2/3 gene deletions is encouraged in order to minimize the overestimation of their prevalence.
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