Genetic Profiling of Plasmodium falciparum Antigenic Biomarkers among Asymptomatic Pregnant Women on Intermittent Preventive Treatment with Sulfadoxine-Pyrimethamine from Southwest Nigeria

doi:10.21203/rs.3.rs-3726650/v1

Download PDF

Research Article

Genetic Profiling of Plasmodium falciparum Antigenic Biomarkers among Asymptomatic Pregnant Women on Intermittent Preventive Treatment with Sulfadoxine-Pyrimethamine from Southwest Nigeria

https://doi.org/10.21203/rs.3.rs-3726650/v1

This work is licensed under a CC BY 4.0 License

Version 1

posted

You are reading this latest preprint version

Background

The genetic complexity of Plasmodium falciparum is a contributory factor to the emergence of drug-resistant parasites. The WHO recommends intermittent preventive treatment of malaria in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) in malaria endemic settings. This study evaluated the prevalence of the Plasmodium falciparum multidrug resistance-1 gene (mdr-1), genetic diversity of merozoite surface proteins (msp-1, msp-2) and glutamate-rich protein (glurp) among pregnant women from southwest Nigeria.

Methods

One hundred PCR-confirmed Plasmodium falciparum isolates, comprising visit 1 (V1) (n = 52), delivery (n = 31) and cord blood (n = 17), were randomly selected for analysis. The mdr-1 haplotypes were evaluated using restriction fragment length polymorphism (RLFP), while the msp-1, msp-2 and glurp genes were genotyped using nested PCR. Allelic frequencies, proportions and multiplicity of infection were calculated, and the p value was considered ≤ 0.05.

Results

The mdr-1 (N86/N86Y) combination was detected in 11.8% (V1), 61.3% (delivery) and 58.8% (cord blood) from the isolates (p ≤ 0.05). The mutant (N86Y) haplotype was detected only in cord isolates (5.9%). The allelic frequency distribution for msp-1 was 245 (K1 = 81, MAD20 = 85 and RO33 = 79), and that for msp-2 was 110, representing 43.6% (FC27) and 56.4% (3D7), respectively. While glurp expressed the least allelic frequency of 25, 84% (V1), 12% (delivery) and 4% (cord), respectively (p ≤ 0.05). msp-1 and msp-2 recorded higher MOIs than glurp.

Conclusion

Antigenic falciparum strains with N86Y Pfmdr-1, msp-1, msp-2, and glurp may compromise the effectiveness of IPTp-SP in southwest Nigeria. The search for newer drug formulations for IPTp may be needed.

Genetic diversity

Plasmodium falciparum mdr-1

msp-1

msp-2

glurp

pregnant women

Nigeria

Pregnant women are one of the most vulnerable populations at risk of malaria infection (Chaponda et al., 2015; Okoyo et al., 2021; Oyerogba et al., 2023). Malaria in pregnancy is deleterious and poses a high risk to both the mother and fetus in endemic regions (Chua et al., 2021), particularly Nigeria, which bears the highest burden of global malaria (WHO 2022). Adverse effects associated with malaria in pregnancy include maternal anemia, fetal loss, premature delivery, intrauterine growth retardation, and low birth weight at delivery, which are risk factors for neonatal death(Bakken & Iversen, 2021; Berhe et al., 2023). In sub-Saharan Africa, the World Health Organization (WHO) recommends effective preventive intervention for controlling malaria during pregnancy with insecticide-treated nets (ITNs), intermittent preventive treatment with at least three doses of sulfadoxine-pyrimethamine (IPTp-SP), starting from the second trimester and, when necessary, appropriate case management through prompt and effective treatment of confirmed malaria cases with artemisinin-based combination therapies (ACTs) (WHO 2016). However, according to the Nigeria National Malaria Indicator Survey, only 17% percent of pregnant women received optimal (≥ 3) doses of SP during intermittent preventive treatment in pregnancy (IPTp), and an estimated 11% of maternal deaths are due to malaria(Akpa et al., 2019; Npc & ICF, 2019).

Plasmodium falciparum is the most virulent species with complex genetic structure and the predominant species in Nigeria (Crabb & Cowman, 2002; Funwei et al., 2018; Orimadegun et al., 2021). The complex genetic composition of Plasmodium falciparum is implicated in parasite selection and circumvention to antimalarial drug therapies (Carrasquilla et al., 2022), resulting in reduced parasite susceptibility, which is a precursor for the emergence of resistant parasite clones (Sissoko et al., 2023).

The prevalence of single nucleotide polymorphisms (SNPs) in the dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes is implicated in the reduced effectiveness of IPTp-SP (Apinjoh et al., 2019; Figueroa-Romero et al., 2023), necessitating newer pipelines for IPTp (Jagannathan et al., 2018; Muthoka et al., 2023).

The emergence of artemisinin-resistant parasites and their gradual spread to sub-Saharan Africa is a major public health burden to global malaria elimination efforts (Ashley et al., 2014; Oladipo et al., 2022; Phyo et al., 2012; Phyo & Nosten, 2018). Artemisinin-based combination therapies (ACTs) are efficacious and remain the first (artemether-lumefantrine) and second-line (artesunate-amodiaquine) antimalarial drugs for the treatment of uncomplicated P. falciparum malaria in Nigeria (Falade et al., 2023). They are co-formulated with artemisinin derivatives; artesunate, artemether or dihydroartemisinin with a partner drug; lumefantrine, amodiaquine, pyronaridine or piperaquine (Falade et al., 2023; Kamya et al., 2007; Koko et al., 2022). However, reduced susceptibility to malaria parasites and confirmed cases of resistant parasites have been reported in the Greater Mekong subregion of Southeast Asia (Amato et al., 2018; Phyo & Nosten, 2018) and have gradually spread to Africa (Balikagala et al., 2021), Eritrea (Mihreteab et al., 2023), Rwanda (Uwimana et al., 2020, 2021) and Uganda (Asua et al., 2021; Ikeda et al., 2018).

The emergence of resistant parasites has threatened the WHO recommended guideline to treat malaria in pregnancy with ACTs during the second and third trimesters of pregnancy, which is widely adopted for the management of confirmed malaria cases during pregnancy in sub-Saharan Africa (WHO 2023). The P. falciparum multidrug resistance-1 (mdr-1) gene is reported to confer resistance to lumefantrine and amodiaquine; the partner drugs to artemisinin derivatives (Adamu et al., 2020; Venkatesan et al., 2014). The P. falciparum mdr-1 gene encodes the P-glycoprotein, which acts as a transporter molecule within the parasite and is involved in the efflux of various drugs and toxins from the parasite, making it an essential factor in the development of resistance to multiple antimalarial drugs (Wicht et al., 2020). Mutations in the P. falciparum mdr-1 gene can lead to altered P-glycoprotein function, resulting in reduced drug sensitivity and increased resistance to antimalarial drugs (Gil & Fançony, 2021; Wicht et al., 2020). These mutations are of significant interest for molecular surveillance of antimalarial drug resistance in areas of malaria endemicity.

Furthermore, the genetic diversity and multiclonality of P. falciparum infection are used to elucidate the pathogenesis and transmission intensity of malaria (Mahdi Abdel Hamid et al., 2016). Plasmodium falciparum genetic diversity is defined by notable genes encoding several membrane proteins, including the merozoite surface proteins (MSP-1, MSP-2) and glutamate rich protein (GLURP) (Santamaría et al., 2020). These membrane proteins have been extensively studied as targets for antimalarial vaccine candidates, but the genetic diversity associated with these genes limits their development as malaria vaccine candidates (Patel et al., 2017). However, the msp-1, msp-2 and glurp genes are implicated as distinct markers to evaluate and understand malaria transmission intensity and multiplicity of infection (MOI) and distinguish reinfection from recrudescent parasites during therapeutic efficacy studies of antimalarial drugs (Mwingira et al., 2011).

Thus, this study evaluated the prevalence of the Plasmodium falciparum multidrug resistance-1 gene and the genetic diversity of the msp-1, msp-2 and glurp genes among pregnant women on IPTp-SP from southwest Nigeria.

Study site and patient enrollment

A cross-sectional study design was adopted, which was nested in a larger prospective study conducted among pregnant women attending antenatal clinics (ANC) between June 2018 and December 2020 in five health facilities: Babcock University Teaching Hospital (BUTH), Ilishan Community Hospital (ICH), Ikenne Primary Health Care Centre (IKPHC), Christ Apostle Church Spiritual and Healing Maternity Home (CAC) and Isara General Hospital (ISH) in Ikenne and Remo North Local Government areas of Ogun State, Southwest Nigeria.

Sample Collection

Of the 520 pregnant women who participated in the larger study, 100 dried blood spot (DBS) obtained from participants who completed ≥ 3 oral doses of intermittent preventive treatment of malaria with sulfadoxine-pyrimethamine (IPTp-SP) with subpatent falciparum malaria through PCR confirmation were randomly selected and included for analysis. The distribution of samples collected includes at enrollment (visit 1; n = 52), during child delivery (n = 31) and cord blood (n = 17) taken immediately after childbirth by a medical officer. In the primary study, participants with confirmed malaria at enrollment and follow up were treated with artemether-lumefantrine (AL).

Map showing LGAs of Ogun state, Nigeria

Genomic DNA Extraction and PCR analysis

Genomic DNA was extracted from whole blood using the QIAamp DNA mini kit (Qiagen, Hilden, Germany) following the manufacturer's instructions. A nested PCR protocol with genus- and species-specific primers targeting 18S ribosomal RNA (18S rRNA) was used to detect Plasmodium falciparum as previously described (Funwei et al., 2018; Snounou et al., 1993). Briefly, in a 20 µL final reaction volume, a PCR mixture containing 5 µL of 5X PCR Master Mix (Solis Biodyne, Estonia), 0.5 mM each of forward and reverse primers, nuclease-free PCR grade water, and 100 ng DNA template was prepared for the primary reaction. In the nested (secondary) reaction, 2 µL of the primary PCR product was used as template into a volume of 18 µL PCR mixture containing the same reagents as the primary reaction except for the species-specific forward and reverse primers. The PCR thermal cycling conditions were as previously described (Snounou et al., 1993). In each of the PCR runs, a template-free control and a known P. falciparum-positive isolate were used as negative and positive controls.

Multidrug resistant-1 (mdr-1) Gene Amplification and RFLP Analysis

The Plasmodium falciparum multidrug resistance-1 (mdr-1) gene was amplified with specific primers in a final reaction volume of 25 µL, containing 8 µL of 5X Master mix (Solis Biodyne, Estonia), 1 mM each of forward (A1) and reverse (A3) primers, 10 µL nuclease-free PCR grade water and 100 ng DNA template for the primary reaction (Dossou-Yovo et al., 2020). A similar PCR mix was prepared for the nested reaction except that 3 µL from the primary PCR product was used as the template and for the second set of forward (A2) and reverse (A4) primers (Dossou-Yovo et al., 2020). The PCR thermal cycling conditions were as previously described (Dossou-Yovo et al., 2020). Amplicons were further subjected to restriction fragment length polymorphism (RLFP) with Apo1 (New England Biolabs Inc.) restriction-digestion enzyme to detect mutation at codon N86.

Allelic genotyping of Plasmodium falciparum msp-1, msp-2 and glurp genes

The msp-1, msp-2, and glurp genes of P. falciparum were amplified with a nested PCR protocol with specific primers as previously described(Funwei et al., 2018; Mwingira et al., 2011; Snounou et al., 1993). The primers used for the primary reaction targeted the conserved outer regions of block 2, block 3, and R2 of the msp-1, msp-2 and glurp genes, respectively, while the nested reaction used primers targeting the inner regions and specific allelic families of msp-1 (K1, MAD20, and R033), msp-2 (3D7 and FC27) and glurp (R2), respectively. Each of the genes (msp-1, msp-2 and glurp) was amplified in a separate PCR run. The PCR mix and thermal cycling conditions were as previously described. (Funwei et al., 2018; Mwingira et al., 2011; Snounou et al., 1999).

Assessment of multiplicity of infection

The multiplicity of infection (MOI), defined as the average number of amplified genotypes per infection from an individual, was calculated by dividing the total number of distinct msp-1 and msp-2 and glurp genotypes by the number of positive samples for each marker(Congpuong et al., 2014). Multiclonal infection was defined as parasites with more than one genotype, while the presence of a single genotype was considered a monoclonal infection (Mahdi Abdel Hamid et al., 2016).

Gel electrophoresis

The amplicons were electrophoresed on 1.5% (msp-1, msp-2, glurp) and 2% (mdr-1) agarose gels, pre-stained with EZ-vison Blue dye (avantor™) and allowed to run in an electrophoretic tank at 100 volts for 1h. After electrophoresis, the gel was placed on a UV transilluminator and visualized for fragment size differentiation. A 100 base pair molecular DNA maker (Ladder, Solis Biodyne) was used for base pair standardization.

Statistical analyses

Data were entered into an Excel spreadsheet and exported to SPSS software (version 20) for statistical analysis. Allelic frequencies (msp-1, msp-2 and glurp) were calculated as the proportion of the allele detected for each allelic family out of the total alleles detected. Multiclonal infection was calculated by counting the number of isolates with more than one clone. The chi-square test was used to compare proportionality. The level of statistical significance was considered at p < 0.05.

Baseline clinical characteristics

The study evaluated one hundred PCR-confirmed subpatent malaria cases from pregnant women attending antenatal clinics in five health facilities within the study location. The baseline clinical characteristics were similar and comparable in all study sites. The mean age of the participants across the facilities was 28 ± 6 years, and body temperature was similar and afebrile (mean temperature = 36.3 ± 0.5°C). The mean body weight, height, body mass index (BMI) and hemoglobin level were similar across the study facilities (Table 1).

Table 1

Baseline clinical characteristics
Study Site	Age (years) Mean ± SD	Temp (^oC) Mean ± SD	Weight (kg) Mean ± SD	Height (cm) Mean ± SD	BMI Mean ± SD	Hemoglobin (g/dl) Mean ± SD
BUTH (n = 55)	30 ± 4	36.4 ± 0.2	73.4 ± 17.8	160.0 ± 6.6	28.5 ± 6.0	10.2 ± 1.5
CAC (n = 18)	26 ± 7	36.4 ± 0.6	59.8 ± 12.6	161.4 ± 7.0	22.9 ± 4.8	9.3 ± 1.1
ICH (n = 13)	27 ± 6	36.4 ± 0.5	66.1 ± 1	161.5 ± 13.3	26.0 ± 8.7	9.5 ± 1.2
IKPHC (n = 9)	27 ± 7	36.0 ± 0.9	62.9 ± 14.0	156.7 ± 6.0	26.0 ± 7.6	8.9 ± 0.9
ISH (n = 5)	26 ± 6	35.7 ± 0.9	61.6 ± 5.9	166.5 ± 7.8	22.4 ± 3.8	8.3 ± 1.3
Total (N = 100)	28 ± 6	36.3 ± 0.5	68.5 ± 17.1	160.5 ± 7.9	26.56 ± 6.6	9.7 ± 1.5

Prevalence of the Plasmodium falciparum multidrug resistance-1 gene

The wild type (N86) of P. falciparum mdr-1 was predominant (98.1%) on visit one (V1), while the mutant genotype (N86Y) was completely absent in the V1 isolates. However, 1.9% of the wild/mutant (N86/N86Y) haplotype was detected. Similarly, 32.2% of the delivery samples harbored the wild-type, 61.3% harbored the wild-type/mutant haplotype, and 6.5% failed to amplify either the wild-type, mutant or mixed haplotype. Only the cord sample harbored a 5.9% mutant genotype, with 58.8% mixed type and 35.3% wild type. In all, 67% wild, 1% mutant and 30% mixed haplotypes were detected (Table 2).

Table 2

Distribution of the pfmdr-1 gene
Sample Type	Wild (%)	Mutant (%)	Mixed (%)	None (%)
Visit 1 (n = 52)	51 (98.1)	0 (0)	1 (1.9)	0 (0)
Delivery (n = 31)	10 (32.2)	0 (0)	19 (61.3)	2 (6.5)
Cord (n = 17)	6 (35.3)	1 (5.9)	10 (58.8)	0 (0)
TOTAL (N = 100)	67 (67)	1 (1)	30 (30)	2 (2)

The allelic frequency distribution across the different study sites showed that BUTH had the highest (129/245; 52.7%) allelic frequency, with MAD20 and RO33 having 34.9% (45/129) each. Similarly, msp-2 recorded 110 alleles, with BUTH having the predominant frequency (45/110; 40.9%). ISH recorded the lowest allelic frequency for msp-1 and glurp, while IKPHC had the lowest frequency for msp-2 (Fig. 1).

The total allelic frequency distribution for msp-1 was 245 alleles (K1 = 81, MAD20 = 85 and RO33 = 79; p = 0.894). Of this, V1 recorded the highest proportion of allelic frequency (125/245; 51.0%), followed by isolates from delivery samples (79/245; 32.3%) and cord samples (43/245; 17.6%). There was a significant difference with respect to the msp-1 allelic frequency distribution of V1, delivery and cord isolates (p = 0.000). The 250–300 base pair size was predominant for K1 (18.8%), while 200–250 bp was the predominant allele for MAD20 (16.7%). All base pair sizes were between 150 and 200 bp for RO33 (32.2%).

Similarly, msp-2 had a total 110 allelic frequency, representing 43.6% (FC27) and 56.4% (3D7), respectively (p = 0.0576). The total msp-2 allelic frequency distribution was 65/110 (59.1%) for V1. Delivery was recorded in 32/110 (29.1%), while 13/110 (11.8%) were detected in cord isolates (p = 0.000). The predominant base pair size for FC27 was 350–450 bp (17.3%), while 200–300 bp was predominant in the 3D7 (29.1%) allelic family.

The glurp gene had the lowest allelic frequency (25), and V1 had the highest allelic frequency (21/25; 84%), followed by delivery isolates (3/25; 12%) and cord isolates (1/25; 4%) (p = 0.000) (Table 4). The highest multiclonal infection was detected in msp-1 (3.2) and msp-2 (2.7) of the delivery isolate, while V1 isolates recorded multiclonality of msp-1 (2.7), msp-2 (2.1) and glurp (1.1). No multiclonal infection for glurp was detected in either delivery or cord isolates (Fig. 2).

Table 4

Allelic frequency distribution of *msp-1*, *msp-2* and *glurp* genes by sample type
Genes (Total Alleles)	Allele Family	Size (bp)	Visit 1 (%)	Delivery (%)	Cord (%)	Total (%)	P value
msp1 (245)	K1 (81)	150–200	13 (16.1)	14 (17.3)	4 (4.9)	31 (12.6)
		250–300	26 (32.1)	13 (16.1)	7 (8.6)	46 (18.8)
		350–400	0 (0)	1 (1.2)	1 (1.2)	2 (0.8)	0.000
		450–550	0 (0)	2 (2.5)	0 (0)	2 (0.8)
	MAD20 (85)	100–150	14 (16.5)	10 (11.8)	5 (5.9)	29 (11.8)
		200–250	20 (23.5)	12 (11.1)	9 10.6)	41 (16.7)
		300–400	9 (10.6)	4 (4.7)	2 (2.6)	15 (6.1)
	RO33 (79)	150–200	41(51.9)	23 (29.1)	15 (19)	79 (32.2)
MOI			2.7	3.2	1.9		0.659
msp-2 (110)	FC27 (48)	200–300	3 (6.3)	8 (16.7)	1 (2.1)	12 (10.9)
		350–450	9 (18.8)	7 (14.6)	3 (6.3)	19 (17.3)
		500–600	5 (10.4)	4 (8.3)	1 (2.1)	10 (9.1)	0.000
		700–850	4 (8.3)	1 (2.1)	0 (0)	5 (4.5)
		900–1000	2 (4.2)	0 (0)	0 (0)	2 (1.8)
	3D7 (62)	200–300	18 (29)	8 (12.9)	6 (9.7)	32 (29.1)
		400–500	15 (24.2)	4 (6.5)	2 (3.2)	21 (19.1)
		600–700	2 (3.2)	0 (0)	0 (0)	2 (1.8)
		800–900	7 (11.3)	0 (0)	0 (0)	7 (6.4)
MOI			2.1	2.7	1.9		0.916
glurp (25)		800–900	9 (36.0)	0 (0)	0 (0)	9 (36.0)
		1000–1100	11 (44.0)	1 (4.0)	1 (4.0)	13 (52.0)	0.000
		1150–1200	1 (4.0)	2 (8.0)	0 (0)	3 (12.0)
MOI			1.1

The baseline characteristics of the study participants were similar and comparable from the five study sites because it was a homogeneous population even though the study spanned two local government areas. The prevalence of subclinical malaria in the study population was high, and malaria transmission occurred year round in the study region, as previously reported elsewhere (Uyaiabasi et al., 2023). The persistence of subclinical malaria despite optimal doses of IPTp-SP has raised concerns about the effectiveness of IPTp-SP in the study location. A similar study conducted in northern Ghana reported a 16.9% malaria prevalence after pregnant women had taken at least 3 doses of IPTp-SP (Agyeman et al., 2020). Subclinical malaria following SP prophylaxis during pregnancy is not only a major drawback to global efforts to reduce malaria in pregnancy, but malaria elimination programs will be grossly hampered because sub-clinical but parasitaemic individuals will continue to serve as parasite reservoirs for malaria transmission in malaria endemic areas (Mlugu et al., 2020)

Mutations found in the P. falciparum mdr-1 genotypes in the study population will further orchestrate reduced susceptibility to ACTs because P. falciparum mdr-1 has been implicated in artemisinin partner drug resistance (Mungthin et al., 2010). A similar study from the northern hemisphere of Nigeria also corroborated the P. falciparum mdr-1 mutation in the country (Adamu et al., 2020). However, a study conducted in Burkina Faso asserted that a low proportion of highly resistant mutant Plasmodium falciparum genes does not reduce the efficacy of ACT partner drugs, drugs used in IPTp and seasonal malaria chemoprevention (Tarama et al., 2023). Our study supports this finding as ACTs and IPTp-SP are still efficacious in Nigeria (Falade et al., 2023; Onoja et al., 2022). This could mean geographic variation may influence parasite selection, antimalarial drug efficacy and the reason why resistant parasites occur at different time points across different malaria endemic settings (Barnadas et al., 2015; Schousboe et al., 2015).

The predominance of wild-type mdr-1 at V1 and mixed/mutant genotypes at delivery and cord isolates may require further investigation. It is unclear whether SP pressure during IPTp may be the driver for Plasmodium falciparum mdr-1 selection because our study detected more mutant mdr-1 parasites as pregnancy progressed to term. Again, it can be suggested that while P. falciparum sequesters in the placenta (Ayres Pereira et al., 2016), it may undergo biological processes that may support parasite mutation(Chang et al., 2013). Therefore, sequestered parasites in the placenta require thorough elucidation of the immunological interplay and subclinical malaria vis-à-vis genetic evolution of the infecting parasite clones during pregnancy. Although the immune system may be somewhat compromised during pregnancy, it is activated to suppress certain pathogens to maintain the well-being of the mother and the fetus (Mor & Cardenas, 2010). Bridging this gap will provide high-throughput interventions and strategies in malaria preventive care during pregnancy aimed at promoting better pregnancy outcomes.

Plasmodium falciparum multidrug resistance-1 (mdr-1) and treatment of malaria in pregnancy is of significant concern in the study. It has been reported that the Plasmodium falciparum mdr-1 gene is responsible for the transport of several drugs out of the parasite's cells, thereby reducing their effectiveness(Si et al., 2023). The mdr-1 mutant parasites may render ACTs ineffective in the management of confirmed malaria cases during pregnancy since the mdr-1 mutation is associated with decreased susceptibility to lumefantrine (Mungthin et al 2010).

The potential threat of Plasmodium falciparum mdr-1 during IPTp-SP regimens necessitates proactive measures to mitigate its impact by regular surveillance of Plasmodium falciparum mdr-1 mutations in the study region. Additionally, timely detection of emerging drug resistance patterns can inform treatment policies and help to guide the selection of appropriate alternative drugs for IPTp. Other antimalarial drug options may be needed, especially in regions where Plasmodium falciparum dihydrofolate reductase (dhfr) and dihydropteroate (dhps) mutations are highly prevalent. Combination therapies with different mechanisms of action, such as dihydro-artemisinin-piperaquine, have been suggested by many authors as alternatives to SP (Muthoka et al., 2023).

Furthermore, the genetic diversity of Plasmodium falciparum msp-1, msp-2 and glurp genes is a potential threat to the effectiveness of intermittent preventive treatment in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP). The IPTp-SP regimen is a key strategy recommended by the WHO to prevent malaria in pregnant women living in areas with moderate to high malaria transmission (WHO 2017). The administration of SP during routine antenatal care visits aims to achieve therapeutic levels of the drug in blood, thereby preventing malaria infection and its adverse effects on both the mother and fetus. However, the effectiveness of IPTp-SP depends on the susceptibility of the circulating Plasmodium falciparum strains to the drug. The msp1, msp-2, and glurp genes are highly polymorphic, which enables them to exist in multiple clones within the parasite population and may contribute to the reduced effectiveness of IPTp-SP. However, resistance to SP occurs through mutations in the parasite's dhfr and dhps genes (primary targets of SP). The presence of extensively diverse msp-1, msp-2, and glurp alleles in the parasite population may further reduce the effectiveness of IPTp-SP in the study location.

Nonetheless, msp-1, msp-2, and glurp are important vaccine candidate antigens against malaria, but their extensive genetic diversity has hampered their development into effective vaccines since antigenic variation can enable the parasite to evade the host immune response (Adu et al., 2016; Dodoo et al., 2011). To mitigate the potential threat of genetic diversity in Plasmodium falciparum during the IPTp-SP regimen, there is a need to intensify vector control measures, such as increased utilization of insecticide-treated bed nets, indoor residual spraying and proper drainage systems. Furthermore, continuous research into novel antimalarial drug candidates is essential to address evolving parasite biology and adopt innovative control mechanisms to overcome the malaria burden during pregnancy.

The limitation of the study was the small number of isolates analyzed and the inability to carry out sequencing due to paucity of fund.

Plasmodium falciparum multidrug resistance-1 (mdr-1), msp-1, msp-2, and glurp genetic diversity may pose a potential threat to the effectiveness of the IPTp-SP regimen in southwest Nigeria. Molecular surveillance and monitoring of antimalarial drug efficacy and research into new drug formulations during IPTp are recommended.

Acknowledgements

We appreciate the Research Innovation and International cooperation (RIIC) unit, Babcock University, Ilishan-Remo, Ogun State, Nigeria, for supporting this work. We also appreciate EDCTP for funding the primary study (EDCTP2 programme -98867IPTp-SP resistance in Nigeria TMA 2015 CDF – 973); where the samples for this study was gotten.

Funding

This study was financially supported by the Babcock University Seed Grant (BURG/22/002) through the office of Research Innovation and International cooperation (RIIC) unit, Babcock University, Ilishan-Remo, Ogun State, Nigeria.

Contributions

FRI and WO conceived and designed the study. OA, UGN, ECJ, AA and OC collected clinical data. FRI and HW carried out the molecular analysis and interpreted the data. FRI wrote the manuscript. AA, OO, FC AA and WO critically reviewed the manuscript. All authors reviewed the final version of the manuscript. All authors read and approved the final manuscript.

Corresponding author

Roland Ibenipere Funwei

Department of Pharmacology,

Babcock University,

Ilishan-Remo Ogun, Nigeria.

Email: [email protected]

Ethics declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests

Adamu A, Jada MS, Haruna HMS, Yakubu BO, Ibrahim MA, Balogun EO, Sakura T, Inaoka DK, Kita K, Hirayama K, Culleton R, Shuaibu MN. Plasmodium falciparum multidrug resistance gene-1 polymorphisms in Northern Nigeria: Implications for the continued use of artemether-lumefantrine in the region. Malar J. 2020;19(1):439. https://doi.org/10.1186/s12936-020-03506-z.
Adu B, Cherif MK, Bosomprah S, Diarra A, Arthur FKN, Dickson EK, Corradin G, Cavanagh DR, Theisen M, Sirima SB, Nebie I, Dodoo D. Antibody levels against GLURP R2, MSP1 block 2 hybrid and AS202.11 and the risk of malaria in children living in hyperendemic (Burkina Faso) and hypo-endemic (Ghana) areas. Malar J. 2016;15:123. https://doi.org/10.1186/s12936-016-1146-4.
Agyeman YN, Newton SK, Annor RB, Owusu-Dabo E. (2020). The Effectiveness of the Revised Intermittent Preventive Treatment with Sulphadoxine Pyrimethamine (IPTp-SP) in the Prevention of Malaria among Pregnant Women in Northern Ghana. Journal of Tropical Medicine, 2020, e2325304. https://doi.org/10.1155/2020/2325304.
Akpa CO, Akinyemi JO, Umeokonkwo CD, Bamgboye EA, Dahiru T, Adebowale AS, Ajayi IO. Uptake of intermittent preventive treatment for malaria in pregnancy among women in selected communities of Ebonyi State, Nigeria. BMC Pregnancy Childbirth. 2019;19(1):457. https://doi.org/10.1186/s12884-019-2629-4.
Amato R, Pearson RD, Almagro-Garcia J, Amaratunga C, Lim P, Suon S, Sreng S, Drury E, Stalker J, Miotto O, Fairhurst RM, Kwiatkowski DP. Origins of the current outbreak of multidrug-resistant malaria in southeast Asia: A retrospective genetic study. Lancet Infect Dis. 2018;18(3):337–45. https://doi.org/10.1016/S1473-3099(18)30068-9.
Apinjoh TO, Ouattara A, Titanji VPK, Djimde A, Amambua-Ngwa A. (2019). Genetic diversity and drug resistance surveillance of Plasmodium falciparum for malaria elimination: Is there an ideal tool for resource-limited sub-Saharan Africa? Malaria Journal, 18. https://doi.org/10.1186/s12936-019-2844-5.
Ashley, E. A., Dhorda, M., Fairhurst, R. M., Amaratunga, C., Lim, P., Suon, S., Sreng,S., Anderson, J. M., Mao, S., Sam, B., Sopha, C., Chuor, C. M., Nguon, C., Sovannaroth,S., Pukrittayakamee, S., Jittamala, P., Chotivanich, K., Chutasmit, K., Suchatsoonthorn,C., … White, N. J. (2014). Spread of Artemisinin Resistance in Plasmodium falciparum Malaria. New England Journal of Medicine, 371(5), 411–423. https://doi.org/10.1056/NEJMoa1314981.
Asua V, Conrad MD, Aydemir O, Duvalsaint M, Legac J, Duarte E, Tumwebaze P, Chin DM, Cooper RA, Yeka A, Kamya MR, Dorsey G, Nsobya SL, Bailey J, Rosenthal PJ. Changing Prevalence of Potential Mediators of Aminoquinoline, Antifolate, and Artemisinin Resistance Across Uganda. J Infect Dis. 2021;223(6):985–94. https://doi.org/10.1093/infdis/jiaa687.
Ayres Pereira M, Clausen M, Pehrson T, Mao C, Resende Y, Daugaard M, Riis Kristensen M, Spliid A, Mathiesen C, Knudsen LE, Damm L, Theander PG, Hansson TR, Nielsen SA, M., Salanti A. Placental Sequestration of Plasmodium falciparum Malaria Parasites Is Mediated by the Interaction Between VAR2CSA and Chondroitin Sulfate A on Syndecan-1. PLoS Pathog. 2016;12(8):e1005831. https://doi.org/10.1371/journal.ppat.1005831.
Bakken L, Iversen PO. The impact of malaria during pregnancy on low birth weight in East-Africa: A topical review. Malar J. 2021;20(1):348. https://doi.org/10.1186/s12936-021-03883-z.
Balikagala B, Fukuda N, Ikeda M, Katuro OT, Tachibana S-I, Yamauchi M, Opio W, Emoto S, Anywar DA, Kimura E, Palacpac NMQ, Odongo-Aginya EI, Ogwang M, Horii T, Mita T. Evidence of Artemisinin-Resistant Malaria in Africa. N Engl J Med. 2021;385(13):1163–71. https://doi.org/10.1056/NEJMoa2101746.
Barnadas C, Timinao L, Javati S, Iga J, Malau E, Koepfli C, Robinson LJ, Senn N, Kiniboro B, Rare L, Reeder JC, Siba PM, Zimmerman PA, Karunajeewa H, Davis TM, Mueller I. (2015). Significant geographical differences in prevalence of mutations associated with Plasmodium falciparum and Plasmodiumvivax drug resistance in two regions from Papua New Guinea. Malaria Journal, 14. https://doi.org/10.1186/s12936-015-0879-9.
Berhe AD, Doritchamou JYA, Duffy PE. Malaria in pregnancy: Adverse pregnancy outcomes and the future of prevention. Front Trop Dis. 2023. 10.3389/fitd.2023.1229735. 4https://www.frontiersin.org/articles/.
Carrasquilla M, Early AM, Taylor AR, Ospina AK, Echeverry DF, Anderson TJC, Mancilla E, Aponte S, Cárdenas P, Buckee CO, Rayner JC, Sáenz FE, Neafsey DE, Corredor V. Resolving drug selection and migration in an inbred South American Plasmodium falciparum population with identity-by-descent analysis. PLoS Pathog. 2022;18(12):e1010993. https://doi.org/10.1371/journal.ppat.1010993.
Chang H-H, Moss EL, Park DJ, Ndiaye D, Mboup S, Volkman SK, Sabeti PC, Wirth DF, Neafsey DE, Hartl DL. (2013). Malaria life cycle intensifies both natural selection and random genetic drift. Proceedings of the National Academy of Sciences, 110(50), 20129–20134. https://doi.org/10.1073/pnas.1319857110.
Chaponda EB, Chandramohan D, Michelo C, Mharakurwa S, Chipeta J, Chico RM. High burden of malaria infection in pregnant women in a rural district of Zambia: A cross-sectional study. Malar J. 2015;14(1):380. https://doi.org/10.1186/s12936-015-0866-1.
Chua CLL, Hasang W, Rogerson SJ, Teo A. (2021). Poor Birth Outcomes in Malaria in Pregnancy: Recent Insights Into Mechanisms and Prevention Approaches. Frontiers in Immunology, 12. https://www.frontiersin.org/articles/10.3389/fimmu.2021.621382.
Congpuong K, Sukaram R, Prompan Y, Dornae A. Genetic diversity of the msp-1, msp-2, and glurp genes of Plasmodium falciparum isolates along the Thai-Myanmar borders. Asian Pac J Trop Biomed. 2014;4(8):598–602. https://doi.org/10.12980/APJTB.4.2014APJTB-2014-0156.
Crabb BS, Cowman AF. Plasmodium falciparum virulence determinants unveiled. Genome Biol. 2002;3(11). https://doi.org/10.1186/gb-2002-3-11-reviews1031. reviews1031.1-reviews1031.4.
Dodoo D, Atuguba F, Bosomprah S, Ansah NA, Ansah P, Lamptey H, Egyir B, Oduro AR, Gyan B, Hodgson A, Koram KA. Antibody levels to multiple malaria vaccine candidate antigens in relation to clinical malaria episodes in children in the Kasena-Nankana district of Northern Ghana. Malar J. 2011;10(1):108. https://doi.org/10.1186/1475-2875-10-108.
Dossou-Yovo LR, Ntoumi F, Koukouikila-Koussounda F, Vouvoungui JC, Adedoja A, Nderu D, Velavan TP, Lenga A. Molecular surveillance of the Pfmdr1 N86Y allele among Congolese pregnant women with asymptomatic malaria. Malar J. 2020;19(1):178. https://doi.org/10.1186/s12936-020-03246-0.
Falade CO, Orimadegun AE, Olusola FI, Michael OS, Anjorin OE, Funwei RI, Adedapo AD, Olusanya AL, Orimadegun BE, Mokuolu OA. Efficacy and safety of pyronaridine-artesunate versus artemether-lumefantrine in the treatment of acute uncomplicated malaria in children in South–West Nigeria: An open-labeled randomized controlled trial. Malar J. 2023;22(1):154. https://doi.org/10.1186/s12936-023-04574-7.
Figueroa-Romero, A., Bissombolo, D., Meremikwu, M., Ratsimbasoa, A., Sacoor, C., Arikpo,I., Lemba, E., Nhama, A., Rakotosaona, R., Llach, M., Pons-Duran, C., Sanz, S., Ma,L., Doderer-Lang, C., Maly, C., Roman, E., Pagnoni, F., Mayor, A., Menard, D., … Menéndez,C. (2023). Prevalence of molecular markers of resistance to sulfadoxine–pyrimethamine before and after community delivery of intermittent preventive treatment of malaria in pregnancy in sub-Saharan Africa: A multicountry evaluation. The Lancet Global Health, 11(11), e1765–e1774. https://doi.org/10.1016/S2214-109X(23)00414-X.
Funwei RI, Thomas BN, Falade CO, Ojurongbe O. Extensive diversity in the allelic frequency of Plasmodium falciparum merozoite surface proteins and glutamate-rich protein in rural and urban settings of southwestern Nigeria. Malar J. 2018;17(1):1. https://doi.org/10.1186/s12936-017-2149-5.
Gil JP, Fançony C. (2021). Plasmodium falciparum Multidrug Resistance Proteins (pfMRPs). Frontiers in Pharmacology, 12. https://www.frontiersin.org/articles/10.3389/fphar.2021.759422.
Ikeda, M., Kaneko, M., Tachibana, S.-I., Balikagala, B., Sakurai-Yatsushiro, M., Yatsushiro,S., Takahashi, N., Yamauchi, M., Sekihara, M., Hashimoto, M., Katuro, O. T., Olia,A., Obwoya, P. S., Auma, M. A., Anywar, D. A., Odongo-Aginya, E. I., Okello-Onen,J., Hirai, M., Ohashi, J., … Mita, T. (2018). Artemisinin-Resistant Plasmodium falciparum with High Survival Rates, Uganda, 2014–2016. Emerging Infectious Diseases, 24(4), 718–726. https://doi.org/10.3201/eid2404.170141.
Jagannathan, P., Kakuru, A., Okiring, J., Muhindo, M. K., Natureeba, P., Nakalembe,M., Opira, B., Olwoch, P., Nankya, F., Ssewanyana, I., Tetteh, K., Drakeley, C., Beeson,J., Reiling, L., Clark, T. D., Rodriguez-Barraquer, I., Greenhouse, B., Wallender,E., Aweeka, F., … Dorsey, G. (2018). Dihydroartemisinin-piperaquine for intermittent preventive treatment of malaria during pregnancy and risk of malaria in early childhood:A randomized controlled trial. PLoS Medicine, 15(7), e1002606. https://doi.org/10.1371/journal.pmed.1002606.
Kamya MR, Yeka A, Bukirwa H, Lugemwa M, Rwakimari JB, Staedke SG, Talisuna AO, Greenhouse B, Nosten F, Rosenthal PJ, Wabwire-Mangen F, Dorsey G. Artemether-Lumefantrine versus Dihydroartemisinin-Piperaquine for Treatment of Malaria: A Randomized Trial. PLoS Clin Trials. 2007;2(5). https://doi.org/10.1371/journal.pctr.0020020.
Koko VS, Warsame M, Vonhm B, Jeuronlon MK, Menard D, Ma L, Taweh F, Tehmeh L, Nyansaiye P, Pratt OJ, Parwon S, Kamara P, Asinya M, Kollie A, Ringwald P. Artesunate–amodiaquine and artemether–lumefantrine for the treatment of uncomplicated falciparum malaria in Liberia: In vivo efficacy and frequency of molecular markers. Malar J. 2022;21(1):134. https://doi.org/10.1186/s12936-022-04140-7.
Mahdi Abdel Hamid M, Elamin AF, Albsheer MMA, Abdalla AAA, Mahgoub NS, Mustafa SO, Muneer MS, Amin M. (2016). Multiplicity of infection and genetic diversity of Plasmodium falciparum isolates from patients with uncomplicated and severe malaria in Gezira State, Sudan. Parasites & Vectors, 9. https://doi.org/10.1186/s13071-016-1641-z.
Mihreteab S, Platon L, Berhane A, Stokes BH, Warsame M, Campagne P, Criscuolo A, Ma L, Petiot N, Doderer-Lang C, Legrand E, Ward KE, Kassahun Z, Ringwald A, Fidock P, D. A., Ménard D. Increasing Prevalence of Artemisinin-Resistant HRP2-Negative Malaria in Eritrea. N Engl J Med. 2023;389(13):1191–202. https://doi.org/10.1056/NEJMoa2210956.
Mlugu EM, Minzi O, Kamuhabwa AAR, Aklillu E. Prevalence and Correlates of Asymptomatic Malaria and Anemia on First Antenatal Care Visit among Pregnant Women in Southeast, Tanzania. Int J Environ Res Public Health. 2020;17(9):3123. https://doi.org/10.3390/ijerph17093123.
Mor G, Cardenas I. (2010). The Immune System in Pregnancy: A Unique Complexity. American Journal of Reproductive Immunology (New York, N.Y.: 1989), 63(6), 425–433. https://doi.org/10.1111/j.1600-0897.2010.00836.x.
Mungthin M, Khositnithikul R, Sitthichot N, Suwandittakul N, Wattanaveeradej V, Ward SA, Na-Bangchang K. Association between the pfmdr1 gene and in vitro artemether and lumefantrine sensitivity in Thai isolates of Plasmodium falciparum. Am J Trop Med Hyg. 2010;83(5):1005–9. 10.4269/ajtmh.2010.10-0339. PMID: 21036827; PMCID: PMC2963959.
Muthoka EN, Usmael K, Embaye SM, Abebe A, Mesfin T, Kazembe D, Ahmedin M, Namuganza S, Kahabuka M, Atim MG, Manyazewal T. Safety and tolerability of repeated doses of dihydroartemisinin-piperaquine for intermittent preventive treatment of malaria in pregnancy: A systematic review and an aggregated data meta-analysis of randomized controlled trials. Malar J. 2023;22(1):320. https://doi.org/10.1186/s12936-023-04757-2.
Mwingira F, Nkwengulila G, Schoepflin S, Sumari D, Beck H-P, Snounou G, Felger I, Olliaro P, Mugittu K. Plasmodium falciparum msp1, msp2 and glurp allele frequency and diversity in sub-Saharan Africa. Malar J. 2011;10:79. https://doi.org/10.1186/1475-2875-10-79.
Npc NPC-. & ICF. (2019). Nigeria Demographic and Health Survey 2018—Final Report. https://dhsprogram.com/publications/publication-fr359-dhs-final-reports.cfm.
Okoyo C, Githinji E, Muia RW, Masaku J, Mwai J, Nyandieka L, Munga S, Njenga SM, Kanyi HM. Assessment of malaria infection among pregnant women and children below five years of age attending rural health facilities of Kenya: A cross-sectional survey in two counties of Kenya. PLoS ONE. 2021;16(9):e0257276. https://doi.org/10.1371/journal.pone.0257276.
Oladipo HJ, Tajudeen YA, Oladunjoye IO, Yusuff SI, Yusuf RO, Oluwaseyi EM, AbdulBasit MO, Adebisi YA, El-Sherbini MS. Increasing challenges of malaria control in sub-Saharan Africa: Priorities for public health research and policymakers. Annals of Medicine and Surgery. 2022;81:104366. https://doi.org/10.1016/j.amsu.2022.104366.
Onoja H, Nduka FO, Abah AE. Effectiveness and compliance to the use of sulphadoxine-pyrimethamine as a prophylaxis for malaria among pregnant women in Port Harcourt, Rivers State, Nigeria. Afr Health Sci. 2022;22(2):187–93. 10.4314/ahs.v22i2.22. PMID: 36407362; PMCID: PMC9652641.
Orimadegun AE, Funwei RI, Michael OS, Ogunkunle OO, Badejo JA, Olusola FI, Agede O, Anjorin OE, Ajayi IO, Jegede AS, Ojurongbe O, Falade CO. Comparative evaluation of three histidine-rich Protein-2 based rapid diagnostic tests, microscopy and PCR for guiding malaria treatment in Ibadan, Southwest Nigeria. Niger J Clin Pract. 2021;24(4):496. https://doi.org/10.4103/njcp.njcp_491_20.
Oyerogba OP, Adedapo A, Awokson T, Odukogbe A-T, Aderinto N. Prevalence of malaria parasitaemia among pregnant women at booking in Nigeria. Health Sci Rep. 2023;6(6):e1337. https://doi.org/10.1002/hsr2.1337.
Patel P, Bharti PK, Bansal D, Raman RK, Mohapatra PK, Sehgal R, Mahanta J, Sultan AA, Singh N. Genetic diversity and antibody responses against Plasmodium falciparum vaccine candidate genes from Chhattisgarh, Central India: Implication for vaccine development. PLoS ONE. 2017;12(8):e0182674. https://doi.org/10.1371/journal.pone.0182674.
Phyo AP, Nkhoma S, Stepniewska K, Ashley EA, Nair S, McGready R, ler Moo C, Al-Saai S, Dondorp AM, Lwin KM, Singhasivanon P, Day NPJ, White NJ, Anderson TJC, Nosten F. Emergence of artemisinin-resistant malaria on the western border of Thailand: A longitudinal study. Lancet (London England). 2012;379(9830):1960–6. https://doi.org/10.1016/S0140-6736(12)60484-X.
Phyo AP, Nosten F. (2018). The Artemisinin Resistance in Southeast Asia: An Imminent Global Threat to Malaria Elimination. Toward Malaria Elimination - A Leap Forward. https://doi.org/10.5772/intechopen.76519.
Santamaría AM, Vásquez V, Rigg C, Moreno D, Romero L, Justo C, Chaves LF, Saldaña A, Calzada JE. Plasmodium falciparum Genetic Diversity in Panamá Based on glurp, msp-1 and msp-2 Genes: Implications for Malaria Elimination in Mesoamerica. Life. 2020;10(12). https://doi.org/10.3390/life10120319. Article 12.
Schousboe ML, Ranjitkar S, Rajakaruna RS, Amerasinghe PH, Morales F, Pearce R, Ord R, Leslie T, Rowland M, Gadalla NB, Konradsen F, Bygbjerg IC, Roper C, Alifrangis M. Multiple Origins of Mutations in the mdr1 Gene—A Putative Marker of Chloroquine Resistance in P. vivax. PLoS Negl Trop Dis. 2015;9(11):e0004196. https://doi.org/10.1371/journal.pntd.0004196.
Si K, He X, Chen L, Zhang A, Guo C, Li M. (2023). The structure of Plasmodium falciparum multidrug resistance protein 1 reveals an N-terminal regulatory domain. Proceedings of the National Academy of Sciences, 120(32), e2219905120. https://doi.org/10.1073/pnas.2219905120.
Sissoko S, Kone A, Dara A, Oboh MA, Fofana B, Sangare CO, Dembele D, Haidara AS, Diallo N, Toure S, Haidara K, Sanogo K, Doumbo OK, Ouattar A, Amambua-Ngwa A, Djimde AA. Complexity of Plasmodium falciparum infection and genetic variations associated with differences in parasite clearance time in two Malian villages. Res Square. 2023. rs.3.rs-3083860.
Snounou G, Viriyakosol S, Zhu XP, Jarra W, Pinheiro L, do, Rosario VE, Thaithong S, Brown KN. (1993). High sensitivity of detection of human malaria parasites by the use of nested polymerase chain reaction. Molecular and Biochemical Parasitology, 61(2), 315–320.
Snounou G, Zhu X, Siripoon N, Jarra W, Thaithong S, Brown KN, Viriyakosol S. Biased distribution of msp1 and msp2 allelic variants in Plasmodium falciparum populations in Thailand. Trans R Soc Trop Med Hyg. 1999;93(4):369–74.
Tarama CW, Soré H, Siribié M, Débé S, Kinda R, Ganou A, Nonkani WG, Tiendrebeogo F, Bantango W, Yira K, Sagnon A, Ilboudo S, Hien EY, Guelbéogo MW, Sagnon N, Traoré Y, Ménard D, Gansané A. Plasmodium falciparum drug resistance-associated mutations in isolates from children living in endemic areas of Burkina Faso. Malar J. 2023;22:213. https://doi.org/10.1186/s12936-023-04645-9.
Uwimana A, Legrand E, Stokes BH, Ndikumana J-LM, Warsame M, Umulisa N, Ngamije D, Munyaneza T, Mazarati J-B, Munguti K, Campagne P, Criscuolo A, Ariey F, Murindahabi M, Ringwald P, Fidock DA, Mbituyumuremyi A, Menard D. Emergence and clonal expansion of in vitro artemisinin-resistant Plasmodium falciparum kelch13 R561H mutant parasites in Rwanda. Nat Med. 2020;26(10):1602–8. https://doi.org/10.1038/s41591-020-1005-2.
Uwimana, A., Umulisa, N., Venkatesan, M., Svigel, S. S., Zhou, Z., Munyaneza, T.,Habimana, R. M., Rucogoza, A., Moriarty, L. F., Sandford, R., Piercefield, E., Goldman,I., Ezema, B., Talundzic, E., Pacheco, M. A., Escalante, A. A., Ngamije, D., Mangala,J.-L. N., Kabera, M., … Lucchi, N. W. (2021). Association of Plasmodium falciparum kelch13 R561H genotypes with delayed parasite clearance in Rwanda: An open-label,single-arm, multicenter, therapeutic efficacy study. The Lancet Infectious Diseases, 21(8), 1120–1128. https://doi.org/10.1016/S1473-3099(21)00142-0.
Uyaiabasi GN, Olaleye A, Elikwu CJ, Funwei RI, Okangba C, Adepoju A, Akinyede A, Adeyemi OO, Walker O. The question of the early diagnosis of asymptomatic and subpatent malaria in pregnancy: Implications for diagnostic tools in a malaria endemic area. European J Obstetrics Gynecology Reproductive Biology: X. 2023;19:100233. https://doi.org/10.1016/j.eurox.2023.100233.
Venkatesan, M., Gadalla, N. B., Stepniewska, K., Dahal, P., Nsanzabana, C., Moriera,C., Price, R. N., Mårtensson, A., Rosenthal, P. J., Dorsey, G., Sutherland, C. J.,Guérin, P., Davis, T. M. E., Ménard, D., Adam, I., Ademowo, G., Arze, C., Baliraine,F. N., Berens-Riha, N., … Sibley, C. H. (2014). Polymorphisms in Plasmodium falciparum Chloroquine Resistance Transporter and Multidrug Resistance 1 Genes: Parasite Risk Factors that Affect Treatment Outcomes for P. falciparum Malaria after Artemether-Lumefantrine and Artesunate-Amodiaquine. The American Journal of Tropical Medicine and Hygiene, 91(4), 833–843. https://doi.org/10.4269/ajtmh.14-0031.
WHO. (2016). WHO recommendations on antenatal care for a positive pregnancy experience. Retrieved November 16, 2023, from https://www.who.int/publications-detail-redirect/9789241549912.
WHO. (2017). Intermittent preventive treatment of malaria in pregnancy (IPTp), World Health Organization, Geneva. http://www.who.int/malaria/areas/preventive_therapies/pregnancy/en/.
WHO. (2022). Report on malaria in Nigeria. WHO | Regional Office for Africa. Retrieved November 16, 2023, from https://www.afro.who.int/countries/nigeria/publication/report-malaria-nigeria-2022.
WHO. (2023). WHO consolidated Guidelines for malaria. Retrieved November 16, 2023, from https://www.who.int/teams/global-malaria-programme/guidelines-for-malaria.
Wicht KJ, Mok S, Fidock DA. Molecular Mechanisms of Drug Resistance in Plasmodium falciparum Malaria. Annu Rev Microbiol. 2020;74:431–54. https://doi.org/10.1146/annurev-micro020518-115546.

No competing interests reported.

Download PDF

Version 1

posted

You are reading this latest preprint version

Genetic Profiling of Plasmodium falciparum Antigenic Biomarkers among Asymptomatic Pregnant Women on Intermittent Preventive Treatment with Sulfadoxine-Pyrimethamine from Southwest Nigeria

Status:

Version 1

Abstract

Background

Methods

Results

Conclusion

Figures

Introduction

Materials and methods

Study site and patient enrollment

Sample Collection

Genomic DNA Extraction and PCR analysis

Assessment of multiplicity of infection

Gel electrophoresis

Statistical analyses

Results

Baseline clinical characteristics

Discussion

Conclusion

Declarations

References

Additional Declarations

Status:

Version 1