Malaria Journal最新文献

Background: The Plasmodium proteasome emerges as a promising target for anti-malarial drug development due to its potential activity against multiple life cycle stages.

Methods: In this investigation, a comparative analysis was conducted on the structural features of the β5 subunit in the 20S proteasomes of both Plasmodium and humans.

Results: The findings underscore the structural diversity inherent in both proteasomes. The human proteasome β5 subunit reveals a composition rich in β-sheets and adopts a more compact conformation. This structural arrangement limits the ligand binding pocket's capacity to accommodate only small compounds effectively. In contrast, the Plasmodium β5 subunit exhibits a higher prevalence of loop structures, creating a more open and flexible binding pocket. This unique structural characteristic enables the binding of a larger and more diverse array of compounds.

Conclusion: The discernible structural contrast between the human and Plasmodium proteasome β5 subunits holds promise for the identification of Plasmodium-selective compounds. The ability of the Plasmodium proteasome to accommodate a broader range of compounds due to its distinctive structural features opens avenues for drug screening to intending to develop selective anti-malarial agents. This study contributes valuable insights into the structural basis for targeting the Plasmodium proteasome and paves the way for the rational design of compounds with enhanced specificity and efficacy against malaria.

Background: Imported malaria from southern Mozambique drives low levels of disease transmission in KwaZulu-Natal, South Africa. Therefore, the South African Department of Health funded implementation of indoor residual spraying (IRS) in Mozambiquan districts identified as sources of malaria infection for border communities in KwaZulu-Natal. IRS was initiated in districts of Guija, Inharrime, Panda and Zavala. To determine impact of spraying on malaria transmission in these districts, data relating to incidence and prevalence was collected before spraying (2018) and before the second round of spraying was completed (2023). Implementation of IRS was also monitored to ensure optimal spray coverage was achieved.

Methods: The study was a cross-sectional survey conducted in 6 sentinel sites in each of the four afore-mentioned districts, focusing on children 6 months to < 15 years from selected households. There was a baseline and an endline cross-sectional survey. Baseline prevalence took place during March-April 2022 whereas the endline surveys occurred during February-March 2023. One hundred and twenty children from each sentinel site were tested for malaria using rapid diagnostic tests. Monthly malaria cases were obtained from health facilities in each study district. Spray data was obtained from LSDI2 initiative who implemented IRS in the targeted districts.

Results: The study showed a definite impact of IRS on malaria prevalence in the targeted districts. Prevalence for sentinel sites in Guija district indicated that the prevalence of malaria increased slightly from baseline to endline in all sentinel sites in Guija. Overall, there was no significant change in prevalence in Zavala, from baseline to endline (p-value = 0.611). Panda's overall malaria prevalence decreased from 19.20% to 10.82% (p-value < 0.001) whereas overall prevalence in Inharrime, decreased from 27.68% to 19.50% (p-value < 0.001). Malaria prevalence in children younger than 5 years decreased significantly in all four districts. In Panda there was a decrease in numbers of males and females being infected between surveys (p < 0.001), whereas for Inharrime the decrease was significant in females (p < 0.001). High coverage with IRS (> 95%) resulted in greater population protection.

Conclusion: The study revealed that IRS implementation decreased malaria prevalence in Inharrime and Panda but not in Guija and Zavala. To ensure that cross-border movement of people does not result in increased malaria transmission, targeting areas identified as source of infection in travelers is paramount to reaching elimination.

Background: Foreign migrant workers from malaria-endemic regions play a critical factor in the transmission of malaria to non-endemic areas, mainly due to their mobility while seeking employment opportunities. This risk is particularly heightened in areas where malaria vectors are present.

Methods: This study aimed to investigate the malaria vectors in two sub-districts in Khon Kaen Province, known for their factory areas and the significant presence of Myanmar migrant worker communities. The collection was carried out from June 2020 to May 2021. The black light traps (BLT) operated continuously from 6:00 pm to 6:00 am (12 h) and Kelambu trap (KT) were set up from 6:00 pm to 9:00 pm, with both traps set up once a month. A total of 679 female Anopheles mosquitoes were collected near the workplaces and dormitories of these workers. Subsequently, the collected female mosquitoes underwent morphological identification using Standard Thailand keys and polymerase chain reaction analysis with rDNA ITS2 primers.

Results: Morphological identification revealed that 201 (29.6%) belonged to the Barbirostris complex. The remaining Anopheles mosquitoes are in the subgroup Cellia, comprised 437 (64.4%) Anopheles vagus, 39 (5.7%) Anopheles subpictus, and 2 (0.3%) Anopheles annularis. To distinguish the Barbirostris complex, multiplex PCR based on ITS-2 sequences was conducted. Out of the 201 specimens examined, 153 (76.1%) as Anopheles campestris, 36 (17.9%) as Anopheles wejchoochotei, and 12 (6%) as Anopheles dissidens. Additionally, the subgroup Anopheles Cellia was confirmed using specific primers based on ITS-2 sequences.

Conclusions: From the obtained results, An. campestris, An. wejchoochotei, An. vagus and An. annularis are reported as the malaria vectors in Thailand. The findings emphasized the important of addressing the presence of Anopheles malaria vectors, especially in the substantial migrant worker population originating from endemic areas. This situation raises concerns regarding the potential transmission of malaria infections to regions not traditionally affected by the disease. Epidemiological studies on malaria vectors should not solely concentrate on endemic regions but also extend to non-endemic areas because of the mobility of migrant workers throughout the country. This broader approach is crucial for implementing an effective malaria surveillance strategy.

Background: Low malaria parasitaemia is a diagnostic challenge in pregnancy, leading to false negative microscopy and rapid diagnostic test (RDT) results. However, these submicroscopic or subpatent infections could cause adverse pregnancy outcomes. Thus, evaluating the diagnostic performance of microscopy, RDT, and multiplex qPCR in pregnancy is vital for informed decisions.

Methods: A total of 835 peripheral blood and 372 placental blood samples were collected from 835 pregnant women attending first antenatal care or admitted for delivery at selected health facilities in northwest Ethiopia between November 2021 and July 2022. In multiplex qPCR, all microscopy and/or RDT positive samples were extracted and amplified individually, whereas all samples negative by both RDT and microscopy were extracted after pooling ten samples together and tested for Plasmodium genus. The diagnostic performance of microscopy, RDT, and multiplex qPCR in pregnancy was compared and evaluated against each other.

Results: Using multiplex qPCR as a reference test, microscopy had a sensitivity of 73.8% (95% confidence interval (CI): 65.9-80.7) and 62.2% (95% CI: 46.5-76.2) to detect Plasmodium parasites in peripheral and placental blood samples, respectively, with a 100% (95% CI: 98.9-100) specificity in both samples. Similarly, the RDT had a sensitivity of 67.6% (95% CI: 59.3-75.1) and a specificity of 96.5% (95% CI: 94.9-97.8) for Plasmodium infection diagnosis in peripheral blood and a sensitivity of 62.2% (95% CI: 46.5-76.2) and a specificity of 98.8% (95% CI: 96.9-99.7) in placental blood samples. Considering microscopy as a reference test, multiplex qPCR showed a sensitivity of 100% (95% CI: 96.6-100) and a specificity of 94.8% (95% CI: 93.0-96.3) to diagnose Plasmodium infections in both peripheral and placental blood samples. Pooled multiplex qPCR detected 34 peripheral and 12 placental blood Plasmodium infections from microscopy and RDT negative samples. The pooled assay obviated about half of the reactions and its testing costs. Microscopy showed almost perfect agreement (κ = 0.823) with multiplex qPCR for detecting malaria parasites in pregnancy, whereas the RDT showed a substantial agreement (κ = 0.684).

Conclusion: Multiplex qPCR had a better performance for Plasmodium infection diagnosis in pregnancy compared to microscopy and RDT. Pooled multiplex qPCR could be a sensitive and resource-efficient strategy for epidemiological surveillance of Plasmodium infections in pregnancy.

Malaria remains a significant public health challenge, particularly in low- and middle-income countries, despite ongoing efforts to eradicate the disease. Recent advancements, including the rollout of malaria vaccines, such as RTS,S/AS01 and R21/Matrix-M™, offer new avenues for prevention. However, the rise of resistance to anti-malarial medications necessitates innovative strategies. This review explores the potential integration of CRISPR/Cas9 gene drive technology with malaria vaccination efforts to enhance vector control and reduce transmission. By employing gene drive mechanisms for population suppression and replacement of malaria-transmitting Anopheles mosquitoes, combined with the immunogenic properties of vaccines, a synergistic approach can be established. This paper discussed the need for integrated strategies to address the biological complexities of malaria and socio-economic factors influencing its prevalence. Challenges such as regulatory hurdles, community acceptance, ecological impacts, and sustainable funding are examined, alongside strategies for implementation within existing malaria control programmes. This integrated approach could significantly contribute to achieving the World Health Organization's targets for malaria reduction by 2030, ultimately enhancing public health outcomes and supporting broader socio-economic development.

Background: Global progress toward malaria elimination and eradication goals has stagnated in recent years, with many African countries reporting increases in malaria morbidity and mortality. Insecticide-treated nets and indoor residual spraying are effective, but the emergence and increased intensity of insecticide resistance and the challenge of outdoor transmission are undermining their impact. New tools are needed to get back on track towards global targets. This Perspective explores the major challenges hindering wider-scale implementation of larviciding in Africa and identifies potential solutions and opportunities to overcome these barriers.

Larviciding in africa: OVERVIEW, CHALLENGES, AND SOLUTIONS: Larviciding is a valuable vector control tool with strong potential for regional scale-up. There is considerable evidence of its effectiveness, and the World Health Organization (WHO) recommends it as a supplemental intervention. However, malaria programmes hoping to implement larviciding face significant barriers, including (1) poor global technical, policy, and funding support; (2) fragmented implementation and experience; (3) high complexity of delivery and impact evaluation; and (4) limited access to the full range of WHO prequalified larvicide products. Strategic barriers related to global policy and donor hesitancy can be overcome through a coordinated demonstration of cost-effectiveness. Technological advancements and strengthened operational capacity have already overcome technical barriers related to larvicide delivery, targeting, coverage, and evaluation. Developing a Community of Practice platform for larviciding has strong potential to consolidate efforts, addressing the challenge of fragmented implementation and experience. Such a platform can serve as a resource center for African malaria programmes, collating and disseminating technical guidance, facilitating the exchange of best practices, and aiding malaria programmes and partners in designing and evaluating larviciding projects.

Conclusion: The global shift toward targeted and adaptive interventions enables the incorporation of larviciding into an expanded vector control toolbox. As more African countries implement larvicide programmes, establishing a regional Community of Practice platform for exchanging experiences and best practices is necessary to strengthen the evidence base for cost-effective implementation, advocate for support, and inform policy recommendations, thus supporting Africa's progress toward malaria elimination.

Background: Acceptability of malaria chemoprevention interventions by caregivers is crucial for overall programme success. This study assessed coverage and acceptability of Seasonal Malaria Chemoprevention (SMC) in selected communities in the Northern part of Ghana.

Methods: An analytical cross-sectional design was conducted from "July 23rd to August 4th, 2020-a 12-day period that covered 5 days of the first SMC implementation cycle and 7 days post-implementation. Using a stratified multi-stage sampling technique, a total of 495 caregivers providing care for 569 eligible children aged 3-59 months from randomly selected households in the study communities were enrolled into the study. Acceptability of SMC was assessed on a set of 19 questionnaire items-8 of the items measured caregivers' perceptions and 11 items measured children's reaction to administered medicines. Univariable and stepwise multivariable logistic regression analyses were performed to assess the predictors of acceptability of SMC at a 95% confidence interval and a p-value of 0.05.

Results: SMC coverage was 95.1% (541/569). Caregivers had a good level of knowledge of SMC (n = 475; 96.0%; 95% CI 94.2-97.7%) and a good perception of SMC (n = 471; 95.2%; 95% CI 93.3-97.0). Seven out of ten caregivers (70.9%; 95% CI 66.9-74.9%) had good acceptability of SMC. For 7 out of 28 children who did not receive the SMC intervention, their caregivers intentionally refused them the intervention. Of those that received the treatment, 17.2% (n = 85; 95%CI 13.8-20.5%) of caregivers had at least one leftover amodiaquine tablet after the third day of treatment. Caregivers who practice Christianity or Islam had better acceptability than caregivers who practice African traditional religion (p < 0.001).

Conclusion: Health authorities and stakeholders can work towards bridging the gap between knowledge and SMC treatment practices of caregivers through continuous education, adherence counseling, and effective monitoring of SMC practices in malaria-endemic countries.

Background: The increased occurrence of malaria among Africa's displaced communities poses a new humanitarian problem. Understanding malaria epidemiology among the displaced population in African refugee camps is a vital step for implementing effective malaria control and elimination measures. As a result, this study aimed to generate comprehensive and conclusive data from diverse investigations undertaken in Africa.

Methods: This review adhered to PRISMA standards, involving searches across electronic data bases such as Google Scholar, PubMed, Web of Science, Scopus, and Science Direct. In addition, grey literature was retrieved from several professional associations. The quality of selected studies was evaluated using the Newcastle-Ottawa Quality Assessment Scale. Data extraction was executed using Microsoft Excel, and the meta-analysis was performed with STATA 14 software. A random-effects model was used to estimate the pooled prevalence and associated factors of malaria. Meta-regression and subgroup analysis were used to identify heterogeneity, while funnel plots and Egger's statistical tests assessed the publication bias. Furthermore, a sensitivity analysis was performed.

Results: The overall random-effects pooled prevalence of malaria infection (comprising symptomatic and asymptomatic cases) across all included studies was 35.93% (95% CI 24.71-47.15). This study showed a high level of heterogeneity between studies (I2 = 97.1; P < 0.001). Of the identified Plasmodium species, Plasmodium falciparum constituted 99.3%. The frost plot indicated that the overall prevalence of P. falciparum was 34.94% (95% CI 24.34-45.53). Subgroup analysis revealed significant variation (P < 0.001) in malaria prevalence between asymptomatic and symptomatic cases, with a prevalence of 4.39% (95% CI 2.57-6.21) and 45.10% (95% CI 27.28-62.92), respectively. Lack of insecticide-treated mosquito net utilization (AOR 2.43; 95% CI 1.01-5.88) and living near mosquito breeding sites (AOR 2.76, 95% CI 1.56-4.87) were risk factors of malaria.

Conclusion: This study determined that the pooled prevalence of malaria among displaced individuals in refugee camps was high and exhibited variations across different population groups. This signifying there is still a need to improve and recheck existing malaria prevention and control strategies to establish an effective malaria control and elimination programme in Africa.

Background: In moderate-to-high malaria transmission regions, the World Health Organization recommends intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) alongside insecticide-treated bed nets to reduce the adverse consequences of pregnancy-associated malaria. Due to high-grade Plasmodium falciparum resistance to SP, novel treatment regimens need to be evaluated for IPTp, but these increase pill burden and treatment days. The present qualitative study assessed the acceptability of IPTp-SP plus dihydroartemisinin-piperaquine (DP) in Papua New Guinea, where IPTp-SP was implemented in 2009.

Methods: Individual in-depth interviews (IDIs) and focus group discussions were conducted at health facilities where a clinical trial evaluated IPTp-SP plus DP (three-day regimen) versus IPTp-SP plus DP-placebo. IDIs were conducted with: (1) trial participants at different stages of engagement with ANC and IPTp, e.g. first antenatal clinic visit, subsequent antenatal clinic visits and postpartum; (2) local health workers (nurses, community health workers, midwives, health extension officers, doctors); and (3) representatives of district, provincial and national health authorities involved in programming ANC and IPTp. Focus group discussions comprised pregnant women only, including those engaged in the clinical trial and those receiving routine ANC outside of the trial. All interviews were audio recorded and transcribed. Transcripts were analysed using inductive and deductive thematic analysis applying a framework assessing: affective attitude, burden, ethicality, intervention coherence, opportunity costs, perceived effectiveness, and self-efficacy.

Results: Women expressed positive feelings and attitudes towards SP plus DP/DP-placebo; reported limited side effects; and found the size, number, colour, and taste of study medicines acceptable. Health workers and policymakers were concerned that, compared to SP alone, additional tablets, frequency (three-day regimen), and tablet size might be barriers to acceptability for users outside a non-trial setting. There was a high perceived effectiveness of SP plus DP; most women reported that they did not get malaria or felt sick during pregnancy. Broader healthcare benefits received through trial participation and the involvement of health workers, relatives and community members in the clinical trial enabled antenatal clinic attendance and perceived acceptability of this IPTp regimen.

Conclusions: In the trial context, IPTp-SP plus DP was acceptable to both users and providers. Healthcare providers were concerned about the realities of acceptability and adherence to SP plus DP outside a clinical trial setting.

Background: Under-5 children have been known to bear a significant burden of malaria in endemic countries. Though significant progress has been made towards malaria prevention and control in Nigeria, it is expected that the addition of new malaria prevention strategy, such as perennial malaria chemoprevention (PMC) can contribute to a more rapid decline in malaria cases. This study aimed to determine the prevalence and factors associated with malaria and anaemia among children aged 2-18 months in Osun State.

Methods: A cross-sectional household malariometric study was conducted in 80 communities across eight Local Government areas (LGAs) in Osun State. Ethical approval was obtained from Osun State Health Research Ethical Committee (OSHREC/PRS/569T312/ on the 22nd of May 2023. Malaria test positivity was determined by rapid diagnostic test (RDT) and microscopy. In addition, haemoglobin levels were measured using Haemocue® Hb 201. Caregivers were interviewed on malaria management practices using tools adapted from Nigeria Malaria Indicator Survey.

Results: A total of four hundred children aged 2-18 months were assessed in this study, which was conducted in July 2023. The caregivers were mostly the biological mothers of the children (n = 387, 96.8%). Female children were 51.8% and their male counterparts 48.2% respectively. Malaria positivity rate by RDT was 36.8% and this was higher in children aged 13-18 months (48.0%) and followed by those aged 7-12 months (44.0%). By microscopy, the positivity rate was 12.5% overall, with 15.0% positivity rate among children aged 7-12 months, about 13.5% among those 13-18 months and those aged 2-6 months had the least positivity rate whether by microscopy (8.5%) or RDT (18.5%). Overall, the prevalence of severe anaemia was 4.0%, moderate was 37.3%, mild was 18.3% and the normal was 40.4% respectively. However, higher proportion of moderate anaemia (7.0-9.9 haemoglobin (g/dL)) was reported in older children. Children from medium wealth households (aOR = 0.549; 95% CI 0.306-0.986) and those from rich households (aOR = 0.543; 95% CI 0.283-1.042) had 45.0% reduction in the odds of having malaria, when compared with their counterparts from poor households. In addition, children aged 7-12 months (aOR = 2.856; 95% CI 1.524-5.354) and those aged 13-18 months (aOR = 4.269; 95% CI 2.422-7.526) had higher odds of malaria infection, respectively, when compared with children aged 2-6 months.

Conclusion: Malaria infection and anaemia were found to be higher in older children. Household wealth and child's age were significantly associated with malaria infection. These findings would inform the positioning of PMC intervention touch-points to reduce malaria burden in young children.