METHODS: A cross-sectional community-based study was conducted on 551 participants from five local government areas in Kano State. Blood samples were collected and examined for the presence of Plasmodium species by rapid diagnostic test (RDT), Giemsa-stained thin and thick blood films, and PCR. Moreover, demographic, socioeconomic, and environmental information as well as KAP data were collected using a pre-tested questionnaire.
RESULTS: A total of 334 (60.6 %) participants were found positive for Plasmodium falciparum. The prevalence differed significantly by age group (p
CASE PRESENTATION: A 61 years old asplenic man was admitted to a tertiary referral hospital in Sabah, Malaysia, with severe knowlesi malaria characterized by hyperparasitaemia (7.9 %), jaundice, respiratory distress, metabolic acidosis, and acute kidney injury. He was commenced on intravenous artesunate, but1 day later developed haemoglobinuria, associated with a 22 % reduction in admission haemoglobin. Additional investigations, including a cell-free haemoglobin of 10.2 × 10(5) ng/mL and an undetectable haptoglobin, confirmed intravascular haemolysis. The patient continued on intravenous artesunate for a total of 48 h prior to substitution with artemether-lumefantrine, and made a good recovery with resolution of his haemoglobinuria and improvement of his kidney function by day 3.
CONCLUSIONS: An asplenic patient with hyperparasitaemic severe knowlesi malaria developed haemoglobinuria after treatment with intravenous artesunate. There are plausible mechanisms for increased haemolysis with hyperparasitaemia, and following both splenectomy and artesunate. Although in this case the patient made a rapid recovery, knowlesi malaria patients with this unusual complication should be closely monitored for potential deterioration.
RESULTS: A total of 36 studies met the inclusion criteria for this review. Numerous stakeholders were identified as involved in the intersectoral actions to defeat malaria amongst MMPs. Almost all studies discussed the involvement of Ministry of Health/Public Health (MOH/MOPH). The most frequently assessed intervention among the studies that were included was the coverage and utilization of insecticide-treated nets as personal protective measures (40.5%), followed by the intervention of early diagnoses and treatment of malaria (33.3%), the surveillance and response activities (13.9%) and the behaviour change communication (8.3%). There is a dearth of information on how these stakeholders shared roles and responsibilities for implementation, and about the channels of communication between-and-within the partners and with the MOH/MOPH. Despite limited details in the studies, the intermediate outcomes showed some evidence that the intersectoral collaborations contributed to improvement in knowledge about malaria, initiation and promotion of bed nets utilization, increased access to diagnosis and treatment in a surveillance context and contributed towards a reduction in malaria transmission. Overall, a high proportion of the targeted MMPs was equipped with correct knowledge about malaria transmission (70%, 95% CI 57-83%). Interventions targeting the use of bed nets utilization were two times more likely to reduce malaria incidence amongst the targeted MMPs (summary OR 2.01, 95% CI 1.43-2.6) than the non-users. The various intersectoral actions were often more vertically organized and not fully integrated in a systemic way within a given country or sub-national administrative setting.
CONCLUSION: Findings suggest that interventions supported by the multiple stakeholders had a significant impact on the reduction of malaria transmission amongst the targeted MMPs. Well-designed studies from different countries are recommended to robustly assess the role of intersectoral interventions targeted to MMPs and their impact on the reduction of transmission.
METHODS: A total of 151 P. falciparum isolates were collected between April 2018 and March 2019 from 12 of the governorates in Jazan region. Genomic DNA was extracted from dried blood spots and amplified using nested PCR. Polymorphisms in the propeller domain of the P. falciparum k13 (pfkelch13) gene and point mutations in the P. falciparum dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) genes were identified by sequencing.
RESULTS: No mutations in the pfkelch13 propeller domain were found in any of the 151 isolates. However, point mutations in the pfdhfr and pfdhps genes were detected in 90.7% (137/151) of the isolates. The pfdhfr double mutations N51I + S108N (i.e. ACICNI haplotype) and triple mutations N51I + C59R + S108N (i.e. ACIRNI haplotype) were detected in 47% and 37.8% of the isolates, respectively. Moreover, the pfdhps single mutation at codon A437G and double mutations A437G + K540E (i.e. SGEAAI haplotype) were observed in 4.6% and 51.7% of the isolates, respectively. Interestingly, 23.8%, 25.1 and 12.6% of the isolates had quintuple, quadruple and triple mutated combined pfdhfr-pfdhps genotypes, respectively. Furthermore, significant associations were found between the prevalence of mutant haplotypes and the age, gender and nationality of the patients (P
METHODS: A total of 189 whole blood samples were collected from Telupid Health Clinic, Sabah, Malaysia, from 2008 to 2011. All patients who participated in the study were microscopically malaria positive before recruitment. Complete demographic details and haematological profiles were obtained from 85 patients (13 females and 72 males). Identification of Plasmodium species was conducted using PlasmoNex™ targeting the 18S ssu rRNA gene.
RESULTS: A total of 178 samples were positive for Plasmodium species by using PlasmoNex™. Plasmodium falciparum was identified in 68 samples (38.2%) followed by 64 cases (36.0%) of Plasmodium vivax, 42 (23.6%) cases of P. knowlesi, two (1.1%) cases of Plasmodium malariae and two (1.1%) mixed-species infections (i e, P. vivax/P. falciparum). Thirty-five PlasmoNex™ positive P. knowlesi samples were misdiagnosed as P. malariae by microscopy. Plasmodium knowlesi was detected in all four districts of Sandakan division with the highest incidence in the Kinabatangan district. Thrombocytopaenia and anaemia showed to be the most frequent malaria-associated haematological complications in this study.
CONCLUSIONS: The discovery of P. knowlesi in Sandakan division showed that prospective studies on the epidemiological risk factors and transmission dynamics of P. knowlesi in these areas are crucial in order to develop strategies for effective malaria control. The availability of advanced diagnostic tool PlasmoNex™ enhanced the accuracy and accelerated the speed in the diagnosis of malaria.
METHODS: In order to investigate the efficacy of pre-clinical vaccine candidates in P. knowlesi-infected human cases, this study describes an in vitro invasion inhibition assay, using a P. knowlesi strain adapted to in vitro growth in human erythrocytes, PkA1-H.1. Recombinant proteins of P. knowlesi Duffy binding protein alpha (PkDBPα) and apical membrane antigen 1 (PkAMA1) were produced in Escherichia coli system and rabbit antibodies were generated from immune animals.
RESULTS: PkDBPα and PkAMA1 recombinant proteins were expressed as insoluble and produced as a functional refolded form for this study. Antibodies against PkDBPα and PkAMA1 specifically recognized recombinant proteins and native parasite proteins in schizont-stage parasites on the merozoite organelles. Single and combination of anti-PkDBPα and anti-PkAMA1 antibodies elicited strong growth inhibitory effects on the parasite in concentration-dependent manner. Meanwhile, IgG prevalence of PkDBPα and PkAMA1 were observed in 13.0 and 46.7% in human clinical patients, respectively.
CONCLUSION: These data provide support for the validation of in vitro growth inhibition assay using antibodies of DBPα and AMA1 in human-adapted P. knowlesi parasite PkA1-H.1 strain.
RESULTS: Anti-ICAM-1 and CD36 monoclonal antibodies were able to inhibit and reverse P. falciparum binding of lab and recently adapted patient isolates in vitro. However, reversal of binding was incomplete and varied in its efficiency between parasite isolates.
CONCLUSIONS: The results show that, as a proof of concept, disturbing existing ligand-receptor interactions is possible and could have potential therapeutic value for severe malaria. The variation seen in the degree of reversing existing binding with different parasite isolates and the incomplete nature of reversal, despite the use of high affinity inhibitors, suggest that anti-adhesion approaches as adjunct therapies for severe malaria may not be effective, and the focus may need to be on inhibitory approaches such as vaccines.
METHODS: The study was a randomized controlled parallel-group study, where 372 randomly selected antenatal care attendees were randomly assigned to one of either two groups after collecting baseline data. The intervention group then received a four-hour health education intervention in Hausa language, which was developed based on the IMB model, while the control group received a similarly designed health education on breastfeeding. Follow up data were then collected from the participants at a first (2 months post-intervention) and second (4 months post-intervention) follow up, and at the end of their pregnancies.
RESULTS: For both groups, reported ITN use had increased from baseline (Intervention: Often-14.0%, Almost always-9.1; Control: Often-12.4%; Almost always 16.1%) to the time of second follow up (Intervention: Often -28.10%, Almost always-24.5; Control: Often-17.2%; Almost always 19.5%). Reported IPTp uptake at second follow up was also higher for the intervention group (Intervention: Two doses-59.0%, Three doses 22.3%; Control group: Two doses-48.4%, Three doses-7.0%). The drop in the haematocrit levels was greater for the control group (32.42% to 30.63%) compared to the intervention group (33.09% to 31.93%). The Generalized Linear Mixed Models (GLMM) analysis revealed that the intervention had significantly improved reported ITN use, reported IPTp uptake, and haematocrit levels, but had no significant effect on the incidence of reported malaria diagnosis or babies' birth weights.
CONCLUSIONS: The intervention was effective in improving ITN use, IPTp uptake, and haematocrit levels. It is, therefore, recommended for the modules to be adopted and incorporated into the routine antenatal care programmes in health centres with predominantly Hausa speaking clients.
TRIAL REGISTRATION: Pan African Clinical Trial Registry, PACTR201610001823405. Registered 26 October 2016, www.pactr.org .
METHODS: The halogen lamp was replaced by a low-cost, blue light-emitting diode (LED) lamp. Using a reformulated AO solution, the staining protocol was revised to make use of a concentration gradient instead of uniform staining. To evaluate this new AO diagnostic system, a pilot field study was conducted in the Lake Victoria basin in Kenya.
RESULTS: Without staining failure, malaria infection status of about 100 samples was determined on-site per one microscopist per day, using the improved AO diagnostic system. The improved AO diagnosis had both higher overall sensitivity (46.1 vs 38.9%: p = 0.08) and specificity (99.0 vs 96.3%) than the Giemsa method (N = 1018), using PCR diagnosis as the standard.
CONCLUSIONS: Consistent AO staining of thin blood films and rapid evaluation of malaria parasitaemia with the revised protocol produced superior results relative to the Giemsa method. This AO diagnostic system can be set up easily at low cost using an ordinary light microscope. It may supplement rapid diagnostic tests currently used in clinical settings in malaria-endemic countries, and may be considered as an inexpensive tool for case surveillance in malaria-eliminating countries.
METHODS: Plasmodium berghei infection in male ICR mice was used as the rodent model of choice. The time course of IL-35 expression in the systemic circulation and tissues of P. berghei infected mice as well as their healthy control counterparts was assessed by enzyme linked immunosorbent assay and immunohistochemistry respectively. The effect of modulating IL-35 by recombinant IL-35 protein or neutralizing anti-Epstein-Barr virus-induced gene 3 antibody on the cytokine environment during P. berghei infection was assessed by flow cytometry. Furthermore, the influence of modulating IL-35 on histopathological hallmarks of malaria and disease progression was evaluated.
RESULTS: Interleukin-35 was significantly up regulated in serum and tissues of P. berghei infected mice and correlated with parasitaemia. Neutralization of IL-35 significantly enhanced the release of IFN-γ, decreased the expression of IL-6 and decreased parasitaemia patency. Neutralization of IL-35 was also associated with a tendency towards increased survival as well as the absence of pathological features associated with malaria infection unlike recombinant IL-35 protein administration which sustained a normal course of infection and unfavourable malaria associated histological outcomes in P. berghei infected mice.
CONCLUSION: These results indicate the involvement of IL-35 in P. berghei induced malaria infection. IL-35 neutralization strategies may represent viable therapeutic modalities beneficial for the resolution of malaria infection.
METHODS: Under Thailand's integrated Drug Efficacy Surveillance (iDES), which includes drug-resistance monitoring as part of routine case-based surveillance and responses, specimens were collected from malaria patients (n = 966) between 2018 and 2020. Thirty-one mono P. knowlesi infections (3.1%), most of which were from eastern and southern Thailand, were observed and confirmed by nested PCR assay and DNA sequencing. To evaluate whether these pathogens were from different lineages, cluster analysis based on seven microsatellite genotyping markers and the merozoite surface protein 1 (pkmsp1) gene was carried out. The P. knowlesi pyrimethamine resistance gene dihydrofolate reductase (pkdhfr) was sequenced and homology modelling was constructed.
RESULTS: The results of analysing the seven microsatellite markers and pkmsp1 sequence demonstrated that P. knowlesi parasites from eastern Thailand were of the same lineage as those isolated in Cambodia, while the parasites causing malaria in southern Thailand were the same lineage as those isolated from Malaysia. The sequencing results for the pkdhfr genes indicated the presence of two mutations, Arg34Leu and a deletion at position 105. On analysis with homology modelling, the two mutations were not associated with anti-malarial drug resistance.
CONCLUSIONS: This report compared the genetic populations of P. knowlesi parasites in Thailand from 2018 to 2020 and have shown similar lineages as those isolated in Cambodia and Malaysia of P. knowlesi infection in Thailand and demonstrated that the P. knowlesi parasites were of the same lineages as those isolated in Cambodia and Malaysia. The parasites were also shown to be sensitive to pyrimethamine.
METHODS: A total of 46 csp genes were subjected to polymerase chain reaction amplification. The genes were obtained from P. knowlesi isolates collected from different divisions of Sabah, Malaysian Borneo, and Peninsular Malaysia. The targeted gene fragments were cloned into a commercial vector and sequenced, and a phylogenetic tree was constructed while incorporating 168 csp sequences retrieved from the GenBank database. The genetic diversity and natural evolution of the csp sequences were analysed using MEGA6 and DnaSP ver. 5.10.01. A genealogical network of the csp haplotypes was generated using NETWORK ver. 4.6.1.3.
RESULTS: The phylogenetic analysis revealed indistinguishable clusters of P. knowlesi isolates across different geographic regions, including Malaysian Borneo and Peninsular Malaysia. Nucleotide analysis showed that the csp non-repeat regions of zoonotic P. knowlesi isolates obtained in this study underwent purifying selection with population expansion, which was supported by extensive haplotype sharing observed between humans and macaques. Novel variations were observed in the C-terminal non-repeat region of csp.
CONCLUSIONS: The csp non-repeat regions are relatively conserved and there is no distinct cluster of P. knowlesi isolates from Malaysian Borneo and Peninsular Malaysia. Distinctive variation data obtained in the C-terminal non-repeat region of csp could be beneficial for the design and development of vaccines to treat P. knowlesi.
METHODS: A total of 36 full-length pkmsp1p sequences along with the reference H-strain and 40 C-terminal pkmsp1p sequences from clinical isolates of Malaysia were downloaded from published genomes. Genetic diversity, polymorphism, haplotype and natural selection were determined using DnaSP 5.10 and MEGA 5.0 software. Genealogical relationships were determined using haplotype network tree in NETWORK software v5.0. Population genetic differentiation index (F ST ) and population structure of parasite was determined using Arlequin v3.5 and STRUCTURE v2.3.4 software.
RESULTS: Comparison of 36 full-length pkmsp1p sequences along with the H-strain identified 339 SNPs (175 non-synonymous and 164 synonymous substitutions). The nucleotide diversity across the full-length gene was low compared to its ortholog pvmsp1p. The nucleotide diversity was higher toward the N-terminal domains (pkmsp1p-83 and 30) compared to the C-terminal domains (pkmsp1p-38, 33 and 19). Phylogenetic analysis of full-length genes identified 2 distinct clusters of P. knowlesi from Malaysian Borneo. The 40 pkmsp1p-19 sequences showed low polymorphisms with 16 polymorphisms leading to 18 haplotypes. In total there were 10 synonymous and 6 non-synonymous substitutions and 12 cysteine residues were intact within the two EGF domains. Evidence of strong purifying selection was observed within the full-length sequences as well in all the domains. Shared haplotypes of 40 pkmsp1p-19 were identified within Malaysian Borneo haplotypes.
CONCLUSIONS: This study is the first to report on the genetic diversity and natural selection of pkmsp1p. A low level of genetic diversity and strong evidence of negative selection was detected and observed in all the domains of pkmsp1p of P. knowlesi indicating functional constrains. Shared haplotypes were identified within pkmsp1p-19 highlighting further evaluation using larger number of clinical samples from Malaysia.
METHODS: The prevalence of G6PD deficiency among 408 Thai participants diagnosed with malaria by microscopy (71), and malaria-negative controls (337), was assessed using a phenotypic test based on water-soluble tetrazolium salts. High-resolution melting (HRM) curve analysis was developed from a previous study to enable the detection of 15 common missense, synonymous and intronic G6PD mutations in Asian populations. The identified mutations were subjected to biochemical and structural characterisation to understand the molecular mechanisms underlying enzyme deficiency.
RESULTS: Based on phenotypic testing, the prevalence of G6PD deficiency (T) and intronic (c.1365-13T>C and c.486-34delT) mutations was detected with intermediate to normal enzyme activity. The double missense mutations were less catalytically active than their corresponding single missense mutations, resulting in severe enzyme deficiency. While the mutations had a minor effect on binding affinity, structural instability was a key contributor to the enzyme deficiency observed in G6PD-deficient individuals.
CONCLUSIONS: With varying degrees of enzyme deficiency, G6PD genotyping can be used as a complement to phenotypic screening to identify those who are eligible for 8-aminoquinolines. The information gained from this study could be useful for management and treatment of malaria, as well as for the prevention of unanticipated reactions to certain medications and foods in the studied population.