Sub-microscopic Plasmodium falciparum infections and multiple drug resistant single nucleotide polymorphic alleles in pregnant women from southwestern Nigeria.

OBJECTIVES: The study evaluated sub-microscopic malaria infections in pregnancy using two malaria Rapid Diagnostic Tests (mRDTs), microscopy and RT-PCR and characterized Plasmodium falciparum dihydrofolate reductase (Pfdhfr) and Plasmodium falciparum dihydropteroate synthase (Pfdhps) drug resistant markers in positive samples. METHODS: This was a cross sectional survey of 121 pregnant women. Participants were finger pricked, blood drops were collected for rapid diagnosis with P. falciparum histidine-rich protein 11 rapid diagnostic test kit and the ultra-sensitive Alere Pf malaria RDT, Blood smears for microscopy and dried blood spots on Whatman filter paper for molecular analysis were made. Real time PCR targeting the var acidic terminal sequence (varATS) gene of P. falciparum was carried out on a CFX 96 real time system thermocycler (BioRad) in discriminating malaria infections. For each run, laboratory strain of P. falciparum 3D7 and nuclease free water were used as positive and negative controls respectively. Additionally, High resolution melt analyses was employed for genotyping of the different drug resistance markers. RESULTS: Out of one hundred and twenty-one pregnant women sampled, the SD Bioline™ Malaria Ag P.f HRP2-based malaria rapid diagnostic test (mRDT) detected eight (0.06%) cases, the ultra-sensitive Alere™ malaria Ag P.f rapid diagnostic test mRDT had similar outcome in the same samples as detected by the HRP2-based mRDT. Microscopy and RT-PCR confirmed four out of the eight infections detected by both rapid diagnostic tests as true positive and RT-PCR further detected three false negative samples by the two mRDTs providing a sub-microscopic malaria prevalence of 3.3%. Single nucleotide polymorphism in Pfdhps gene associated with sulphadoxine resistance revealed the presence of S613 mutant genotypes in three of the seven positive isolates and isolates with mixed wild/mutant genotype at codon A613S. Furthermore, four mixed genotypes at the A581G codon were also recorded while the other Pfdhps codons (A436G, A437G and K540E) showed the presence of wild type alleles. In the Pfdhfr gene, there were mutations in 28.6%, 28.6%, and 85.7% at the I51, R59 and N108 codons respectively. Mixed wild and mutant type genotypes were also observed in 28.6% each of the N51I, and C59R codons. For the Pfcrt, two haplotypes CVMNK and CVIET were observed. The SVMNT was altogether absent. Triple mutant CVIET 1(14.3%) and triple mutant + wild genotype CVIET + CVMNK 1(14.3%) were observed. The Pfmdr1 haplotypes were single mutants YYND 1(14.3%); NFND 1(14.3%) and double mutants YFND 4(57.1%); YYDD 1(14.3%).

Detection of novel Plasmodium falciparum coronin gene mutations in a recrudescent ACT-treated patient in South-Western Nigeria.

Background: Routine surveillance for antimalarial drug resistance is critical to sustaining the efficacy of artemisinin-based Combination Therapies (ACTs). Plasmodium falciparum kelch-13 (Pfkelch-13) and non-Pfkelch-13 artemisinin (ART) resistance-associated mutations are uncommon in Africa. We investigated polymorphisms in Plasmodium falciparum actin-binding protein (Pfcoronin) associated with in vivo reduced sensitivity to ART in Nigeria. Methods: Fifty-two P. falciparum malaria subjects who met the inclusion criteria were followed up in a 28-day therapeutic efficacy study of artemether-lumefantrine in Lagos, Nigeria. Parasite detection was done by microscopy and molecular diagnostic approaches involving PCR amplification of genes for Pf18S rRNA, varATS, telomere-associated repetitive elements-2 (TARE-2). Pfcoronin and Pfkelch-13 genes were sequenced bi-directionally while clonality of infections was determined using 12 neutral P. falciparum microsatellite loci and msp2 analyses. Antimalarial drugs (sulfadoxine-pyrimethamine, amodiaquine, chloroquine and some quinolones) resistance variants (DHFR_51, DHFR_59, DHFR_108, DHFR_164, MDR1_86, MDR1_184, DHPS_581 and DHPS_613) were genotyped by high-resolution melting (HRM) analysis. Results: A total of 7 (26.92%) cases were identified either as early treatment failure, late parasitological failure or late clinical failure. Of the four post-treatment infections identified as recrudescence by msp2 genotypes, only one was classified as recrudescence by multilocus microsatellites genotyping. Microsatellite analysis revealed no significant difference in the mean allelic diversity, He, (P = 0.19, Mann-Whitney test). Allele sizes and frequency per locus implicated one isolate. Genetic analysis of this isolate identified two new Pfcoronin SNVs (I68G and L173F) in addition to the P76S earlier reported. Linkage-Disequilibrium as a standardized association index, IAS, between multiple P. falciparum loci revealed significant LD (IAS = 0.2865, P=0.02, Monte-Carlo simulation) around the neutral microsatellite loci. The pfdhfr/pfdhps/pfmdr1 drug resistance-associated haplotypes combinations, (108T/N/51I/164L/59R/581G/86Y/184F), were observed in two samples. Conclusion: Pfcoronin mutations identified in this study, with potential to impact parasite clearance, may guide investigations on emerging ART tolerance in Nigeria, and West African endemic countries.

A survey of chloroquine use for prevention and treatment of COVID-19 in Nigeria.

Background: Rampant chloroquine/hydroxychloroquine poisoning in Nigerian hospitals following suggestions of its possible efficacy in the treatment and prevention of the newly emerged COVID-19 disease informed this survey. Objectives: The aim of this study was to assess the knowledge, attitude and perception of the Nigerian populace on the use of chloroquine in the COVID-19 pandemic. Methods: This cross-sectional study was done by administering an electronic questionnaire created using Google Docs, through social media cascade methods including the WhatsApp application software to capture data on chloroquine use between April 20 and June 20, 2020. Results: Six hundred and twenty-eight people responded to the questionnaire (response rate 99.2%, mean age 41.05 ± 12.3) from the six geopolitical zones in Nigeria with 556 (88.5%) having tertiary level education. Only 21 (3.3%) of the respondents took chloroquine for treatment or prevention. Respondents from the North-west geopolitical zones used chloroquine 5.8 (95% CI: 1.55, 21.52, p=0.02) more times than other zones while the age group 20-29 were 8.8 times more likely to use chloroquine than any other age group (95% CI: 3.53, 21.70, p = 0.00). Female respondents were 2.3 times more likely to use chloroquine than the males (OR 2.26 95% CI: 0.90-5.68; p=0.08) and those in the income bracket of N75,000-99,000, 2.5 times more than other income groups. Conclusion: Young adults, North-western geopolitical zone, and female gender should be target groups for education on rational chloroquine use. The danger of chloroquine overdose should be communicated to the general population in Nigeria.

Contemporary Anti-Retroviral Drugs (ARVDs) Disrupt Follicular Development in Female Wistar Rats.

Introduction: There are genuine concerns that long-term use of anti-retroviral drugs may be associated with reproductive complications in females. This study aimed to ascertain the effect of highly active anti-retroviral drugs on the ovarian reserve and reproductive potential of female Wistar rats and by extension to HIV-positive human females. Methods: A total of 25 female Wistar rats, weighing between 140g and 162g, were randomly allotted into non-intervention and intervention groups, receiving the anti-retroviral drugs, Efavirenz (EFV), Tenofovir Disoproxil Fumarate (TDF), Lamivudine (3TC), and a fixed-dose combination (FDC). The dosage was administered orally at 8 am daily for 4 weeks. Serum concentrations of anti-Mullerian hormone (AMH), follicle-stimulating hormone (FSH), luteinising hormone (LH), and estradiol were measured using standard biochemical techniques (ELISA). Follicular counts were made on fixed ovarian tissue from the sacrificed rats. Results: The mean AMH level for the control group and the EFV, TDF, 3TC, and FDC groups were 11.20, 6.75, 7.30, 8.27, and 6.60 pmol/L, respectively. The EFV and FDC groups had the lowest AMH, compared to the other groups, but there was no statistically significant difference in AMH across the groups. The mean count of antral follicles was significantly lower in the group that received EFV when compared to the other groups. The corpus luteal count was significantly higher in the control group than in the intervention groups. Conclusion: The study demonstrated a disruption in the reproductive hormones of female Wistar rats receiving anti-retroviral regimens containing EFV. Clinical studies are required to determine if these changes are seen in women receiving EFV-based treatment, as this may compromise reproductive function and predispose them to early menopause.

Baseline prevalence of molecular marker of sulfadoxine/pyrimethamine resistance in Ebonyi and Osun states, Nigeria: amplicon deep sequencing of dhps-540.

BACKGROUND: Chemoprevention plays an important role in malaria control strategy. Perennial malaria chemoprevention (PMC) using sulfadoxine/pyrimethamine (SP) is a WHO-approved strategy to combat malaria in young children and may lead to drug pressure. Introducing SP-PMC may therefore be compromised due to the emergence of Plasmodium falciparum resistant to SP, particularly mutation at K540E of the dihydropteroate synthase (dhps) gene. Molecular surveillance of resistance markers can support assessment of antimalarial efficacy and effectiveness. High prevalence of 540E is associated with reduced effectiveness of SP, and areas with more than 50% prevalence are considered unsuitable for intermittent preventative treatment in pregnancy (IPTp) implementation. Assessing 540E prevalence is an important undertaking before implementation of SP-PMC. METHODS: We conducted a rapid surveillance of dhps-540E to assess the suitability of SP as PMC in field studies from Ebonyi and Osun states in Nigeria. We used an in-house developed amplicon deep-sequencing method targeting part of the dhps gene. RESULTS: Our data reveal that 18.56% of individuals evaluated carried the 540E mutation mixed with the WT K540. Mutant variant 540E alone was not found, and 80% of isolates harboured only WT (K540). Clonal analysis of the sequencing data shows a very low proportion of 540E circulating in both states. CONCLUSIONS: Our data show that both states are suitable for SP-PMC implementation and, based on this finding, SP-PMC was implemented in Osun in 2022. Continuous monitoring of 540E will be required to ensure the chemoprevention effectiveness of SP in Nigeria.

Acute and subacute oral toxicity characterization and safety assessment of COVID organics® (Madagascar's Anti­COVID Herbal Tea) in animal models

Introduction: Coronavirus disease 2019 (COVID 19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2. No drug has been generally approved as safe and effective for the treatment of COVID 19. Several therapeutic agents such as COVID Organics® (CVO) have been explored as treatment options. CVO is an herbal tea composed of 62% of Artemisia annua and 38% of other plants. There is presently no existing scientific report and data on the safety and efficacy of CVO herbal drug. Thus, acute and subacute toxicity studies were undertaken to evaluate the safety and toxicity of CVO on short and long term usage in animal models. Materials and Methods: Phytochemical and nutritional compositions of CVO were determined using standard methods. Acute oral toxicity was investigated using female Swiss albino mice (three per group). While subacute oral toxicity was done using female and male Swiss albino rats (five per group). The animals were administered 2000 mg/kg, 5000 mg/kg, therapeutic dose; 5500 mg/kg and supratherapeutic dose; 11,000 mg/kg of CVO herbal product. The control group received water ad libitum. The oral toxicity studies were done in accordance with Organization for Economic Corporation and Development guidelines. The experimental protocol was approved by the Institutional Animal Care and Use Committee, Nigerian Institute of Medical Research (Ethics No. IRB/17/043). Results: CVO is rich in antioxidants: flavonoids(10.3%), tannins(29.1%), and phenolics(434.4 mg). It contains proteins (33.8%), carbohydrates (34.5%), fat (6.8%), and fiber (0.5%). In the acute toxicity study, no mortality was recorded in all the treated and untreated groups. The lethal dose of CVO is >5000 mg/kg body weight. The hematological, biochemical, lipid profile, and histologic parameters were all normal at therapeutic doses when compared to the control group. Conclusion: The acute and subacute oral toxicity studies revealed that CVO is not toxic. The specific organ toxicity evaluations also indicated that CVO has no toxic effects on blood parameters and vital organs structure and function at therapeutic dose. Thus, CVO is safe for short and long term usage. We recommend that CVO should be subjected to efficacy studies to investigate whether it is effective for COVID 19 treatment as claimed by the manufacturer.

Acute and subacute oral toxicity characterization and safety assessment of COVID organics® (Madagascar's Anti-COVID Herbal Tea) in animal models.

Introduction: Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2. No drug has been generally approved as safe and effective for the treatment of COVID-19. Several therapeutic agents such as COVID Organics® (CVO) have been explored as treatment options. CVO is an herbal tea composed of 62% of Artemisia annua and 38% of other plants. There is presently no existing scientific report and data on the safety and efficacy of CVO herbal drug. Thus, acute and subacute toxicity studies were undertaken to evaluate the safety and toxicity of CVO on short- and long-term usage in animal models. Materials and Methods: Phytochemical and nutritional compositions of CVO were determined using standard methods. Acute oral toxicity was investigated using female Swiss albino mice (three per group). While subacute oral toxicity was done using female and male Swiss albino rats (five per group). The animals were administered 2000 mg/kg, 5000 mg/kg, therapeutic dose; 5500 mg/kg and supratherapeutic dose; 11,000 mg/kg of CVO herbal product. The control group received water ad libitum. The oral toxicity studies were done in accordance with Organization for Economic Corporation and Development guidelines. The experimental protocol was approved by the Institutional Animal Care and Use Committee, Nigerian Institute of Medical Research (Ethics No. IRB/17/043). Results: CVO is rich in antioxidants: flavonoids (10.3%), tannins (29.1%), and phenolics (434.4 mg). It contains proteins (33.8%), carbohydrates (34.5%), fat (6.8%), and fiber (0.5%). In the acute toxicity study, no mortality was recorded in all the treated and untreated groups. The lethal dose of CVO is >5000 mg/kg body weight. The hematological, biochemical, lipid profile, and histologic parameters were all normal at therapeutic doses when compared to the control group. Conclusion: The acute and subacute oral toxicity studies revealed that CVO is not toxic. The specific organ toxicity evaluations also indicated that CVO has no toxic effects on blood parameters and vital organs structure and function at therapeutic dose. Thus, CVO is safe for short- and long-term usage. We recommend that CVO should be subjected to efficacy studies to investigate whether it is effective for COVID-19 treatment as claimed by the manufacturer.

Résumé Introduction: La maladie à coronavirus 2019 (COVID-19) est une maladie infectieuse causée par le coronavirus 2 du syndrome respiratoire aigu sévère. Aucun ne médicamenta été généralement approuvé comme étant sûr et efficace pour le traitement du COVID-19. Plusieurs agents thérapeutiques comme le COVID Organics® (CVO) ont été explorées comme options de traitement. CVO est une tisane composée à 62% d'Artemisia annua et à 38% d'autres plantes. Il y a actuellement il n'existe aucun rapport scientifique ni aucune donnée sur l'innocuité et l'efficacité du médicament à base de plantes CVO. Ainsi, des études de toxicité aiguë et subaiguë ont été entreprises évaluer la sécurité et la toxicité du CVO sur une utilisation à court et à long terme dans des modèles animaux. Matériels et méthodes: phytochimiques et les compositions nutritionnelles du CVO ont été déterminées à l'aide de méthodes standard. La toxicité orale aiguë a été étudiée chez des femmes albinos suisses souris (trois par groupe). La toxicité orale subaiguë a été réalisée sur des rats albinos suisses femelles et mâles (cinq par groupe). Les animaux étaient administrés 2 000 mg/kg, 5 000 mg/kg, 5 500 mg/kg (dose thérapeutique) et 11 000 mg/kg (dose suprathérapeutique) de produit à base de plantes CVO. Le le groupe témoin a reçu de l'eau à volonté. Les études de toxicité orale ont été réalisées conformément à l'Organisation pour la société économique et Directives de développement. Le protocole expérimental a été approuvé par le Comité institutionnel de protection et d'utilisation des animaux de l'Institut nigérian de Recherche médicale (Éthique n° IRB/17/043). Résultats: Le CVO est riche en antioxydants : flavonoïdes (10,3 %), tanins (29,1 %) et phénoliques (434,4 mg). Il contient des protéines (33,8 %), des glucides (34,5 %), des lipides (6,8 %) et des fibres (0,5 %). Dans l'étude de toxicité aiguë, aucune mortalité n'a été enregistrée chez tous les groupes traités et non traités. La dose mortelle de CVO est > 5 000 mg/kg de poids corporel. Le profil hématologique, biochimique, lipidique et les paramètres histologiques étaient tous normaux aux doses thérapeutiques par rapport au groupe témoin. Conclusion: Les conséquences orales aiguës et subaiguës des études de toxicité ont révélé que le CVO n'est pas toxique. Les évaluations de la toxicité spécifique pour certains organes ont également indiqué que le CVO n'a aucun effet toxique sur le sang. Paramètres et structure et fonction des organes vitaux à dose thérapeutique. Ainsi, CVO est sans danger pour une utilisation à court et à long terme. Nous recommandons que Le CVO doit être soumis à des études d'efficacité pour déterminer s'il est efficace pour le traitement du COVID-19, comme le prétend le fabricant. Mots-clés: Maladie à coronavirus 2019, plantes médicinales, histopathologie, produits phytochimiques, analyses immédiates, évaluation de la toxicité.

Socio-economic behavioural indicators of falciparum malaria parasitaemia and moderate to severe anaemia among pregnant women attending antenatal clinics in Lagos, Southwest Nigeria.

BACKGROUND: Incidence of malaria and anaemia are of public health importance especially in pregnant women in endemic regions, due to the negative health consequences to the mother and fetus. This study aimed to assess the pattern of falciparum malaria infection and anaemia, based on malaria prevention methods practiced by participants. METHODS: A semi-structured tool was used to capture information on demographic, socio-economic and malaria prevention practices from 113 pregnant women attending antenatal clinics in 2 peri-urban health facilities in Lagos, southwest Nigeria. Malaria microscopy was conducted and haematocrit was measured. Logistic regression analysis was performed on the data collated from the survey. RESULTS: The prevalence of anaemia among pregnant women was 87.2%. The mean (± sd) packed cell volume (PCV) (%) of the 22 (19.5%) infected subjects (26.8 ± 6.6), was significantly lower (t = -2.60, P value = 0.007) than that of the 91 (80.5%) uninfected subjects (30.8 ± 6.0). The prevalence of infection was highest in the 3rd trimester (n = 40, 35.4%) at 27.5% (11/40) and among those in their first pregnancy (n = 32, 28.3%) at 25.0% (8/32). There was a significant difference (t = -2.23, P-value = 0.01) in the mean PCV % of pregnant women who consumed herbal teas in pregnancy (28.2 ± 5.2) compared to those who did not (30.8 ± 6.6). Regression analysis showed that first pregnancy, anti-malarial use and insecticide-treated nets use the night before study had increased odds of malaria infection in participants (OR = 1.35, P = 0.006, 95% CI 0.52-2.49; OR = 2.3, P = 0.005, 95% CI 0.14-0.41; OR = 1.92, P = 0.001, 95% CI 0.62-5.98) while intermittent preventive treatment (IPT) participation and formal education were strongly and significantly associated with lower risk of parasitaemia (OR = 0.95, P = 0.025, 95% CI 0.41-2.26; OR = 0.44, P = 0.005, 95% CI 0.34-10.50). CONCLUSION: Interventions that will reduce malaria and moderate to severe anaemia, especially in a first pregnancy, should include education on the correct use of long-lasting insecticide-treated bed nets (LLIN), IPT and the dangers of herbal teas in pregnancy.

Clinical Probe of Cyp2C8*2 Mutants in a Malaria Hyperendemic Zone: Evidence from North-Central, Nigeria.

BACKGROUND: A tremendous level of success has been achieved since the introduction of chloroquine and the combination of amodiaquine and artemisinin for the treatment of both complicated and uncomplicated malaria infections in sub-Saharan Africa. However, the recent discovery of drug resistant strains of Plasmodium falciparum (P.f.) and the ability of the parasite to ingest CYP2C8 into its digestive vacuole is of great public health concern. This study probes the occurrence of CYP2C8*2 allelic mutant amongst malaria patients in North-Central Nigeria. METHODS: Three hundred and eighty five (385) unrelated study participants were screened for current malaria episodes using routine microscopy and/or rapid diagnostic test strips (RDTs). Chelex extraction method was used for single nucleotide polymorphisms (SNPs) and identification of CYP2C8*2 (805A > T) variant respectively. Wild-type (A) and the defective allele (T) were differentiated with the use of Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP). The results obtained were further validated with Sanger sequencing of a few samples and thereafter, the genotype data were statistically processed. All alleles obtained were in Hardy Weinberg equilibrium. RESULTS: Out of the 385 participants (45.5% Male and 54.5% Female) genotyped for SNPs, 75 (19.5%) had the autosomal recessive mutant trait. Occurrence of mutant traits was gender and ethnic independent (p > 0.05). Yoruba ethnic group recorded a reduction in proportion of genotypic defective CYP2C8*2 allele (T) (1 in every 8 persons) with a carrier percentage of 13.3% compared with Hausa (26.62%); Igbo (25.37%) and other minority ethnic groups (17.6%). CONCLUSIONS: A remarkable inter-ethnic differences in autosomal recessive CYP2C8*2 allele was observed. By implication, there is a gradual incursion of genetic drift for poor CQ and AQ-Artemisinin metabolizers among the inhabitants.

Alterations in histological, biochemical and hematological parameters in Plasmodium berghei NK-65 infected balb/c mice treated with Bridelia ferruginea stem bark extract.

BACKGROUND: Recent ethnomedicinal studies on Bridelia ferruginea Benth (family Phyllanthaceae) as an antiplasmodial remedy have established its potency as a strong prophylactic and chemosuppressive agent. Human consumption of medicinal herbs without adequate evaluation of its efficacy and safety can result in grave physiological and pathological consequences. Therefore, this study assessed the antiplasmodial bioactivity, biochemical, hematological, histopathological and toxicity profile of the ethanolic stem bark extract of B. ferruginea in mice. METHODS: Ethanolic stem bark extract of B. ferruginea (200, 400 and 800 mg/kg) were orally administered to Plasmodium berghei-infected mice in models and were subsequently observed for mortality, behavioral changes and signs of toxicity. Acute evaluation was experimented at 1,000 mg/kg for 28 days. Occult blood obtained from the euthanized mice were subjected to biochemical and hematological assays. A comprehensive assessment of the histology of the liver and kidney was also ascertained. The median lethal dose (LD50) was determined and extrapolated using the regression equation obtained from the plot of the probits of mortalities (y) and the log of doses (log10C). RESULTS: Different concentrations of the phytochemical secondary metabolites were revealed. Antiplasmodial bioactivity was established at the 200, 400 and 800 mg/kg of the herbal extract with a dearth in parasitemia at different days post-treatment. The 800 mg/kg group responded by exhibiting a dose-dependent decrease in parasitemia comparable with the chloroquine bi-phosphate group. Significant alterations in the histology of the liver and kidney of the 1,000 mg/kg group was documented. There was a reduction in the titers of LDH, ALT, AST, and urea in the treated group when compared with the control (p < 0.05). Antioxidant profiles were also highly significant with elevation in SOD, GPx, and CAT, but a reduction in MDA. LD50 was established at 424 mg/kg. CONCLUSION: B. ferruginea Benth (family Phyllanthaceae) is a potent antiplasmodial, antioxidant, regenerative and ameliorative herbal remedy if administered in controlled dosage.

Genetic polymorphisms in malaria vaccine candidate Plasmodium falciparum reticulocyte-binding protein homologue-5 among populations in Lagos, Nigeria.

BACKGROUND: Vaccines are the most reliable alternative to elicit sterile immunity against malaria but their development has been hindered by polymorphisms and strain-specificity in previously studied antigens. New vaccine candidates are therefore urgently needed. Highly conserved Plasmodium falciparum reticulocyte-binding protein homologue-5 (PfRH5) has been identified as a potential candidate for anti-disease vaccine development. PfRH5 is essential for erythrocyte invasion by merozoites and crucial for parasite survival. However, there is paucity of data on the extent of genetic variations on PfRH5 in field isolates of Plasmodium falciparum. This study described genetic polymorphisms at the high affinity binding polypeptides (HABPs) 36718, 36727, 36728 of PfRH5 in Nigerian isolates of P. falciparum. This study tested the hypothesis that only specific conserved B and T cell epitopes on PfRH5 HABPs are crucial for vaccine development. METHODS: One hundred and ninety-five microscopically confirmed P. falciparum samples collected in a prospective cross-sectional study of three different populations in Lagos, Nigeria. Genetic diversity and haplotype construct of Pfrh5 gene were determined using bi-directional sequencing approach. Tajima's D and the ratio of nonsynonymous vs synonymous mutations were utilized to estimate the extent of balancing and directional selection in the pfrh5 gene. RESULTS: Sequence analysis revealed three haplotypes of PfRH5 with negative Tajima's D and dN/dS value of - 1.717 and 0.011 ± 0.020, respectively. A single nucleotide polymorphism, SNP (G → A) at position 608 was observed, which resulted in a change of the amino acid cysteine at position 203 to tyrosine. Haplotype and nucleotide diversities were 0.318 ± 0.016 and 0.0046 ± 0.0001 while inter-population genetic differentiation ranged from 0.007 to 0.037. Five polypeptide variants were identified, the most frequent being KTKYH with a frequency of 51.3%. One B-cell epitope, 151 major histocompatibility complex (MHC) class II T-cell epitopes, four intrinsically unstructured regions (IURs) and six MHC class I T-cell epitopes were observed in the study. Phylogenetic analysis of the sequences showed clustering and evidence of evolutionary relationship with 3D7, PAS-2 and FCB-2 RH5 sequences. CONCLUSIONS: This study has revealed low level of genetic polymorphisms in PfRH5 antigen with B- and T-cell epitopes in intrinsically unstructured regions along the PfRH5 gene in Lagos, Nigeria. A broader investigation is however required in other parts of the country to support the possible inclusion of PfRH5 in a cross-protective multi-component vaccine.

High cases of submicroscopic Plasmodium falciparum infections in a suburban population of Lagos, Nigeria.

BACKGROUND: Asymptomatic malaria parasites are significant sources of infections for onward malaria transmission. Conventional tools for malaria diagnosis such as microscopy and rapid diagnostic test kits (RDT) have relatively low sensitivity, hence the need for alternative tools for active screening of such low-density infections. METHODS: This study tested var acidic terminal sequence-based (varATS) quantitative polymerase chain reaction (qPCR) for screening asymptomatic Plasmodium falciparum infections among dwellers of a sub-urban community in Lagos, Nigeria. Clinically healthy participants were screened for malaria using microscopy, RDT and varATS qPCR techniques. Participants were stratified into three age groups: 1-5, 6-14 and > 14 years old. RESULTS: Of the 316 participants screened for asymptomatic malaria infection, 78 (24.68%) were positive by microscopy, 99 (31.33%) were positive by RDT and 112 (35.44%) by varATS qPCR. Participants aged 6-14 years had the highest prevalence of asymptomatic malaria, with geometric means of ~ 116 parasites/µL and ~ 6689 parasites/µL as detected by microscopy and varATS, respectively. CONCLUSION: This study has revealed high prevalence of asymptomatic malaria in the study population, with varATS detecting additional sub-microscopic infections. The highest concentration of asymptomatic malaria was observed among school-age children between 6 and 14 years old. A large-scale screening to identify other potential hotspots of asymptomatic parasites in the country is recommended.

Impact of training of mothers, drug shop attendants and voluntary health workers on effective diagnosis and treatment of malaria in Lagos, Nigeria.

BACKGROUND: The National Malaria Eradication Program and international agencies are keen on scaling up the use of malaria rapid diagnostic tests (mRDTs) and artemisinin-based combination therapies (ACTs) for effective diagnosis and treatment of the disease. However, poor diagnostic skills and inappropriate treatment are limiting the efforts. In Nigeria, a large proportion of infected patients self-diagnose and treat while many others seek care from informal drug attendants and voluntary health workers. AIMS: This study describes the impact of training voluntary health workers, drug shop attendants, and mothers on effective case detection and treatment of malaria in Lagos, Nigeria. METHODS: We trained mothers accessing antenatal care, drug shop attendants, and voluntary health workers selected from the three districts of Lagos, on the use of histidine-rich protein-2-based mRDTs and ACTs. Pre- and post-training assessments, focus group discussions (FGDs), and in-depth interviews (IDIs) were carried out. RESULTS: The knowledge, attitude, and skill of the participants to achieve the goal of "test, treat, and track" using mRDT and ACTs were low (11%-55%). There was a low awareness of other non-malaria fevers among mothers. Self-medication was widely practiced (31.3%). FGDs and IDIs revealed that health-care providers administered antimalarials without diagnosis. Training significantly improved participants' knowledge and expertise on the use of mRDTs and ACTs (P = 0.02). The participants' field performance on mRDT use was significantly correlated with their category (bivariate r = 0.51, P = 0.001). There was no statistically significant association between the participants' level of education or previous field experience and their field performance on mRDT (r = 0.12, P = 0.9; χ 2= 38, df = 2 and P = 0.49). CONCLUSION: These findings suggest that training of stakeholders in malaria control improves diagnosis and treatment of malaria. However, a broader scope of training in other settings may be required for an effective malaria control in Nigeria.

Intestinal parasitic infections: Current status and associated risk factors among school aged children in an archetypal African urban slum in Nigeria.

BACKGROUND/PURPOSE: Intestinal parasitic infections (IPIs) among school aged children (SAC) in Nigeria remains endemic, hence the need for regular surveillance to attract the attention of policy makers. This cross-sectional study investigated the current prevalence and factors associated with intestinal parasitic infections among school aged children in an urban slum of Lagos City, Nigeria. METHODS: Single stool samples from 384 school aged children (188 boys and 196 girls) were examined by employing Merthiolate-iodine-formaldehyde concentration (MIFC) and Kato-Katz methods. Demographic characteristics and risk factors were obtained by questionnaires investigation. RESULTS: The overall prevalence was 86.2% in school children, out of them 39.1% had polyparasitism. IPIs showed the highest to the lowest prevalence of 62% (238/384), 25% (97/384), 12.3% (47/384), 11.8% (45/384), 9.9% (38/384), 8.4% (32/384), 3.4% (13/384), and 0.5% (2/384) found in Ascaris lumbricoides, Entamoeba histolytica/dispar, Giardia duodenalis, Endolimax nana, Entamoeba coli, Trichuris trichiura, Blastocystis hominis, and hookworm infections, respectively. MIFC technique showed superiority to Kato-Katz technique in the detection of IPIs (p < 0.0001). Drinking untreated water was a significant risk factor for these school aged children in acquiring protozoan infections after multivariate adjustment (OR = 1.86, 95% CI = 1.08-3.20, p = 0.02). CONCLUSION: Intestinal parasitic infections are very severe among school aged children in the urban slums, thus regular mass de-worming programs, health education, and the provision of safe drinking water is recommended to combat IPIs among the school aged children.

A barcode of multilocus nuclear DNA identifies genetic relatedness in pre- and post-Artemether/Lumefantrine treated Plasmodium falciparum in Nigeria.

BACKGROUND: The decline in the efficacy of artemisinin-based combination treatment (ACT) in some endemic regions threatens the progress towards global elimination of malaria. Molecular surveillance of drug resistance in malaria-endemic regions is vital to detect the emergence and spread of mutant strains. METHODS: We observed 89 malaria patients for the efficacy of artemether-lumefantrine for the treatment of uncomplicated Plasmodium falciparum infections in Lagos, Nigeria and determined the prevalence of drug resistant strains in the population. Parasite clearance rates were determined by microscopy and the highly sensitive var gene acidic terminal sequence (varATS) polymerase chain reaction for 65 patients with samples on days 0, 1, 3, 7, 14, 21 and 28 after commencement of treatment. The genomic finger print of parasite DNA from pre- and post-treatment samples were determined using 24 nuclear single nucleotide polymorphisms (SNP) barcode for P. falciparum. Drug resistance associated alleles in chloroquine resistance transporter gene (crt-76), multidrug resistance genes (mdr1-86 and mdr1-184), dihydropteroate synthase (dhps-540), dihydrofolate reductase (dhfr-108) and kelch domain (K-13580) were genotyped by high resolution melt analysis of polymerase chain reaction (PCR) fragments. RESULTS: By varATS qPCR, 12 (18.5%) of the participants had detectable parasite DNA in their blood three days after treatment, while eight (12.3%) individuals presented with genotypable day 28 parasitaemia. Complexity of infection (CoI) was 1.30 on day 0 and 1.34 on day 28, the mean expected heterozygosity (HE) values across all barcodes were 0.50 ± 0.05 and 0.56 ± 0.05 on days 0 and 28 respectively. Barcode (π) pairwise comparisons showed high genetic relatedness of day 0 and day 28 parasite isolates in three (37.5%) of the eight individuals who presented with re-appearing infections. Crt-76 mutant allele was present in 38 (58.5%) isolates. The mdr1-86 mutant allele was found in 56 (86.2%) isolates. No mutation in the K-13580 was observed. CONCLUSIONS: Persistence of DNA-detectable parasitaemia in more than 18% of cases after treatment and indications of genetic relatedness between pre- and post-treatment infections warrants further investigation of a larger population for signs of reduced ACT efficacy in Nigeria.

Evaluation of the Clinical Proficiency of RDTs, Microscopy and Nested PCR in the Diagnosis of Symptomatic Malaria in Ilorin, North-Central, Nigeria.

BACKGROUND: Accurate laboratory diagnosis of suspected malaria is the hallmark to the control of the disease. AIM: The clinical proficiency of commercial Rapid Diagnostic test kits (RDTs) using nested PCR as quality control was evaluated among patients attending two public healthcare providing institutions in Ilorin, Kwara state, North-Central, Nigeria. METHOD: A cross-sectional evaluation of finger prick blood samples of volunteer patients were accessed for malaria parasites with pLDH, HRP2, Pf, Pf/PAN and nested PCR molecular assays. The data derived were analysed using standard formulae for diagnostic accuracy, and the obtained predictive values were subjected to a comparison with one-way analysis of variance (ANOVA). RESULT: Three hundred and sixty-eight (368) patients comprising 203 (55%) females and 165 (45%) males participated in this study. Routine microscopy revealed that 54 (32.7%) males and 80 (39.4%) was infected with Plasmodium falciparum. SD Bioline (pLDH) 47.4%; Carestart Malaria (HRP2) 49.8% recorded low sensitivities. Micropoint (pfPAN) 82.8% and Micropoint (Mal. Pf) 64.4% recorded a high sensitivity. SD Bioline (pLDH) 67.4%; Carestart Malaria (HRP2) 85.9%; Micropoint (PfPAN) 62.2% and Micropoint (Mal. Pf) 86.7% had high specificities. The positive predictive value (PPV) ranged from 67.7% to 85.94%, while the negative predictive values (NPV) of 64.4% for SD Bioline (pLDH); 86.7% for Carestart Malaria (HRP2); 89.3% for Micropoint (pfPAN) and 58.5% for Micropoint (Mal. Pf). Agarose gel analysis of P. falciparumssrRNA gene (206 bp) for 28 specimens containing 10% concordant and discordant samples showed that all 12 negative specimens for RDTs and routine microscopy were truly negative for nPCR. However, the remaining 16 specimens were positive for nPCR and showed discrepancies with routine microscopy and RDTs. Cohen's interrater diagnostic measure analysis revealed that the weighted kappa for the RDTs was moderate 0.417 (p=0.027), 95%CI (0.756, 0.078) and good for nPCR 0.720 (p < 0.001), 95%CI (0.963, 0.477). The area under the curve (AUC) specify that nPCR has been more effective than the RDTs (nPCRAUC = 0.875; p < 0.001 and RDTsAUC = 0.708; p = 0.063). CONCLUSION: A thorough large-scale quality control is advocated on all commercial RDTs being used in most sub-Saharan African countries. This is to avoid double jeopardy consequent upon misdiagnosis on unidentified positive cases serving as pool reservoir for the insect vector and cyclical infection and re-infection of the populace.

Pro-inflammatory Cytokine Response and Genetic Diversity in Merozoite Surface Protein 2 of Plasmodium falciparum Isolates from Nigeria.

BACKGROUND: Polymorphisms in Plasmodium falciparum merozoite surface protein-2 (msp-2) and associated parasite genetic diversity which varies between malaria-endemic regions remain a limitation in malaria vaccine development. Pro-inflammatory cytokines are important in immunity against malaria, understanding the influence of genetic diversity on cytokine response is important for effective vaccine design. METHODS: P. falciparum isolates obtained from 300 Nigerians with uncomplicated falciparum malaria at Ijede General Hospital, Ijede (IJE), General Hospital Ajeromi, Ajeromi (AJE) and Saint Kizito Mission Hospital, Lekki, were genotyped by nested polymerase chain reaction of msp-2 block 3 while ELISA was used to determine the pro-inflammatory cytokine response to describe the genetic diversity of P. falciparum. RESULTS: Eighteen alleles were observed for msp-2 loci. Of the 195 isolates, 61 (31.0%) had only FC27-type alleles, 38 (19.7%) had only 3D7-type alleles, and 49.3% had multiple parasite lines with both alleles. Band sizes were 275-625 bp for FC27 and 150-425 bp for 3D7. Four alleles were observed from LEK, 2 (375-425 bp) and 2 (275-325 bp) of FC27-and 3D7-types, respectively; 12 alleles from AJE, 9 (275-625 bp) and 3 (325-425 bp) of FC27-types and 3D7-types, respectively; while IJE had a total of 12 alleles, 9 (275-625 bp) and 3 (325-425 bp) of FC27-types and 3D7-types, respectively. Mean multiplicity of infection (MOI) was 1.54. Heterozygosity (HE) ranged from 0.77 to 0.87 and was highest for IJE (0.87). Cytokine response was higher among <5 years and was significantly associated with MOI (P > 0.05) but with neither parasite density nor infection type. CONCLUSION: P. falciparum genetic diversity is extensive in Nigeria, protection via pro-inflammatory cytokines have little or no interplay with infection multiplicity.

Toxoplasma gondii infection: seroprevalence and associated risk factors among primary schoolchildren in Lagos City, Southern Nigeria.

INTRODUCTION: Toxoplasma gondii infection has been described as the most widespread zoonotic infection of humans and other animals. Information concerning T. gondii infection among schoolchildren is unavailable in Lagos City, Nigeria. METHODS: This cross-sectional study investigated the seroprevalence and risk factors associated with T. gondii infection among primary schoolchildren (PSC) from a community located in the center of Lagos, southern Nigeria, from November 2013 to March 2014. A total of 382 PSC were screened for the presence of sera anti-T. gondii antibodies using a latex agglutination test (TOXO Test-MT, Tokyo, Japan). A cutoff titer of ≥ 1:32 was considered positive, while titers ≥ 1:1,024 indicated high responders. Questionnaires were also used to obtain data on possible risk factors from parents/guardians. RESULTS: The overall seroprevalence was 24% (91/382), and 83.5% (76/91) of seropositive PSC were classified as high responders. Among the risk factors tested, including contact with cats and soil, consumption of raw meat and vegetables, and drinking unboiled water, none showed statistical significance after multivariate adjustment. No associations were observed among age, gender, body mass index (BMI), and parents' occupation/educational level. CONCLUSIONS: The findings in this study show evidence of active infection, and hence, there is need for urgent preventive measures in this city. Further investigation is required to clarify the transmission routes. Policy makers also need to initiate prevention and control programs to protect pregnant women and immunocompromised patients in particular because they are more severely affected by T. gondii infection.