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47 ud af 47 tidsskrifter valgt, søgeord (malaria) valgt, emner højest 180 dage gamle, sorteret efter nyeste først.
353 emner vises.
Malaria Journal, 16.02.2024
Tilføjet 16.02.2024
Abstract Background Over the last decades, the number of malaria cases has drastically reduced in Cambodia. As the overall prevalence of malaria in Cambodia declines, residual malaria transmission becomes increasingly fragmented over smaller remote regions. The aim of this study was to get an insight into the burden and epidemiological parameters of Plasmodium infections on the forest-fringe of Cambodia. Methods 950 participants were recruited in the province of Mondulkiri in Cambodia and followed up from 2018 to 2020. Whole-blood samples were processed for Plasmodium spp. identification by PCR as well as for a serological immunoassay. A risk factor analysis was conducted for Plasmodium vivax PCR-detected infections throughout the study, and for P. vivax seropositivity at baseline. To evaluate the predictive effect of seropositivity at baseline on subsequent PCR-positivity, an analysis of P. vivax infection-free survival time stratified by serological status at baseline was performed. Results Living inside the forest significantly increased the odds of P. vivax PCR-positivity by a factor of 18.3 (95% C.I. 7.7–43.5). Being a male adult was also a significant predictor of PCR-positivity. Similar risk profiles were identified for P. vivax seropositivity. The survival analysis showed that serological status at baseline significantly correlated with subsequent infection. Serology is most informative outside of the forest, where 94.0% (95% C.I. 90.7–97.4%) of seronegative individuals survived infection-free, compared to 32.4% (95% C.I.: 22.6–46.6%) of seropositive individuals. Conclusion This study justifies the need for serological diagnostic assays to target interventions in this region, particularly in demographic groups where a lot of risk heterogeneity persists, such as outside of the forest.
Læs mere Tjek på PubMedMalaria Journal, 15.02.2024
Tilføjet 15.02.2024
Abstract Background South Africa set a target to eliminate malaria by 2023, with KwaZulu-Natal (KZN) Province the malaria-endemic province closest to achieving this goal. Objective two of the National Malaria Elimination Strategic Plan (NMESP) focused on strengthening surveillance systems to support the country’s elimination efforts. Regular evaluations of the malaria surveillance systems against the targets of the NMESP objective are crucial in improving their performance and impact. This study aimed to assess whether the malaria surveillance system in KwaZulu-Natal Province meets the NMESP surveillance objective and goals. Methods A mixed-methods cross-sectional study design was used to evaluate the malaria surveillance system, focusing on the District Health Information System 2 (DHIS2). The study assessed the data quality, timeliness, simplicity, and acceptability of the system. Key personnel from KZN’s Provincial malaria control programme were interviewed using self-administered questionnaires to evaluate their perception of the system\'s simplicity and acceptability. Malaria case data from January 2016 to December 2020 were extracted from the DHIS2 and evaluated for data quality and timeliness. Results The survey respondents generally found the DHIS2-based surveillance system acceptable (79%, 11/14) and easy to use (71%, 10/14), stating that they could readily find, extract, and share data (64%, 9/14). Overall data quality was good (88.9%), although some variables needed for case classification had low completeness and data availability. However, case notifications were not timely, with only 61% (2 622/4 329) of cases notified within 24 h of diagnosis. During the 5-year study period, the DHIS2 captured 4 333 malaria cases. The majority of cases (81%, 3 489/4 330) were categorized as imported, and predominately in males (67%, 2 914/4 333). Conclusion While the malaria surveillance system in KZN Province largely met the NMESP surveillance strategic goals, it failed to achieve the overarching surveillance objective of 100% notification of cases within 24 h of diagnosis. The majority of reported cases in KZN Province were classified as imported, emphasizing the importance of complete data for accurate case classification. Engaging with healthcare professionals responsible for case notification and disseminating aggregated data back to them is needed to encourage and improve notification timeliness.
Læs mere Tjek på PubMedJournal of Infectious Diseases, 15.02.2024
Tilføjet 15.02.2024
Abstract A large body of evidence suggests that low parasite carriage in Plasmodium falciparum asymptomatic infection is required for the maintenance of malaria immunity. However, the fact that treating such infections has little to no impact on subsequent clinical malaria is rarely noted. In this paper, we review data and argue that low-density parasite carriage in asymptomatic infection may not support host immune processes and that parasites are virtually under the host\'s immunological radar. We also discuss factors that may be constraining parasitemia in asymptomatic infections from reaching the threshold required to cause clinical symptoms. A thorough understanding of this infectious reservoir is essential for malaria control and eradication because asymptomatic infections contribute significantly to Plasmodium transmission.
Læs mere Tjek på PubMedJournal of the American Medical Association, 14.02.2024
Tilføjet 14.02.2024
Mass administration of oral azithromycin is central to the World Health Organization (WHO) campaign to eliminate trachoma. Mass administration of azithromycin could have beneficial effects in young children due to its activity against pathogens causing pneumonia, diarrhea, and malaria, but could also have harmful effects, including generation of antimicrobial resistance. In 2009, a cluster randomized clinical trial showed that mass administration of oral azithromycin was associated with a 49% reduction in mortality in Ethiopian children aged 1 to 9 years. The subsequent Macrolides Oraux pour Réduire les Décès avec un Oeil sur la Résistance (MORDOR) trial in Malawi, Niger, and Tanzania showed that twice-yearly mass distribution of azithromycin to children aged 1 to 59 months reduced mortality by 13.5%, but, among the 3 countries, mortality was reduced significantly only in Niger. In all 3 countries, the greatest benefit was seen in children aged 1 to 5 months. The heterogeneity of results from these studies led to a qualified recommendation from WHO that mass administration of azithromycin could be considered for children aged 1 to 11 months in sub-Saharan African settings with high mortality rates among those younger than 5 years, but that further study was needed before more widespread azithromycin use for reduction of childhood mortality could be recommended.
Læs mere Tjek på PubMedMalaria Journal, 13.02.2024
Tilføjet 13.02.2024
Abstract Background The aim of this study is to design ad hoc malaria learning (ML) approaches to predict clinical outcome in all patients with imported malaria and, therefore, to identify the best clinical setting. Methods This is a single-centre cross-sectional study, patients with confirmed malaria, consecutively hospitalized to the Lazzaro Spallanzani National Institute for Infectious Diseases, Rome, Italy from January 2007 to December 2020, were recruited. Different ML approaches were used to perform the analysis of this dataset: support vector machines, random forests, feature selection approaches and clustering analysis. Results A total of 259 patients with malaria were enrolled, 89.5% patients were male with a median age of 39 y/o. In 78.3% cases, Plasmodium falciparum was found. The patients were classified as severe malaria in 111 cases. From ML analyses, four parameters, AST, platelet count, total bilirubin and parasitaemia, are associated to a negative outcome. Interestingly, two of them, aminotransferase and platelet are not included in the current list of World Health Organization (WHO) criteria for defining severe malaria. Conclusion In conclusion, the application of ML algorithms as a decision support tool could enable the clinicians to predict the clinical outcome of patients with malaria and consequently to optimize and personalize clinical allocation and treatment.
Læs mere Tjek på PubMedMalaria Journal, 12.02.2024
Tilføjet 12.02.2024
Abstract Over the past thirty years, epigenetic regulation of gene expression has gained increasing interest as it was shown to be implicated in illnesses ranging from cancers to parasitic diseases. In the malaria parasite, epigenetics was shown to be involved in several key steps of the complex life cycle of Plasmodium, among which asexual development and sexual commitment, but also in major biological processes like immune evasion, response to environmental changes or DNA repair. Because epigenetics plays such paramount roles in the Plasmodium parasite, enzymes involved in these regulating pathways represent a reservoir of potential therapeutic targets. This review focuses on epigenetic regulatory processes and their effectors in the malaria parasite, as well as the inhibitors of epigenetic pathways and their potential as new anti-malarial drugs. Such types of drugs could be formidable tools that may contribute to malaria eradication in a context of widespread resistance to conventional anti-malarials.
Læs mere Tjek på PubMedMalaria Journal, 12.02.2024
Tilføjet 12.02.2024
Abstract Background Malaria remains an enduring public health concern in Indonesia, exacerbated by its equatorial climate that fosters the proliferation of Anopheles mosquitoes. This study seeks to assess the performance of the malaria elimination programme comprehensively. Methods Between May and August 2022, a qualitative study was conducted in Muara Enim Regency, South Sumatra Province, involving 22 healthcare professionals from diverse backgrounds. These informants were strategically chosen for their pivotal roles in providing profound insights into various facets of the malaria elimination programme. This encompasses inputs such as human resources, budgetary allocation, and infrastructural support; processes like case identification and management, capacity enhancement, epidemiological surveillance, prevention measures, outbreak control, and enhanced communication and educational initiatives; and, notably, the programme’s outcomes. Data were collected through 3-h Focus Group Discussions (FGDs) divided into two groups, each with 12 participants: healthcare professionals and programme managers. Additionally, in-depth interviews (IDIs) were conducted with ten informants. Employing the Input-Process-Output (IPO) model, this study meticulously analysed the healthcare system dynamics and the interventions’ efficacy. Results The study unveiled many challenges during the input phase, including the absence of entomologists and a shortage of diagnostic tools. Despite these obstacles, it documented remarkable accomplishments in the output domain, marked by significant advancements in the distribution of mosquito nets and the successful implementation of the Early Warning System (EWS). Despite the adversities, the programme has made substantial strides towards malaria elimination. Conclusions Urgent action is imperative to bolster the effectiveness of the malaria elimination programme. Key measures encompass augmenting the entomologist workforce, optimizing resource allocation, and ensuring stringent adherence to regional regulations. Addressing these concerns will enhance programme efficacy, yielding enduring public health benefits. This research substantially contributes to Indonesia’s ongoing malaria elimination endeavours, furnishing actionable insights for programme enhancement. Consequently, this research holds significant importance for the malaria elimination drive.
Læs mere Tjek på PubMedIssabella Asamoah, Mildred Adusei-Poku, Priscilla Vandyck-Sey, Allen Steele-Dadzie, Atta Senior Kuffour, Albert Turkson, Ivy Asantewaa Asante, Kantanka Addo-Osafo, Quaneeta Mohktar, Bright Adu, Yaw A. Afrane, Kwamena W. C. Sagoe
PLoS One Infectious Diseases, 10.02.2024
Tilføjet 10.02.2024
by Issabella Asamoah, Mildred Adusei-Poku, Priscilla Vandyck-Sey, Allen Steele-Dadzie, Atta Senior Kuffour, Albert Turkson, Ivy Asantewaa Asante, Kantanka Addo-Osafo, Quaneeta Mohktar, Bright Adu, Yaw A. Afrane, Kwamena W. C. Sagoe Background Malaria is a common and severe public health problem in Ghana and largely responsible for febrile symptoms presented at health facilities in the country. Other infectious diseases, including COVID-19, may mimic malaria due to their shared non-specific symptoms such as fever and headache thus leading to misdiagnosis. This study therefore investigated COVID-19 among patients presenting with malaria-like symptoms at Korle-Bu Polyclinic, Accra, Ghana. Methods This study enrolled 300 patients presenting with malaria-like symptoms aged ≥18yrs. After consent was obtained from study patients, two to three millilitres of whole blood, nasopharyngeal and oropharyngeal swab samples, were collected for screening of Plasmodium falciparum using malaria rapid diagnostic test, microscopy and nested PCR, and SARS-CoV-2 using SARS-CoV-2 antigen test and Real-time PCR, respectively. The plasma and whole blood were also used for COVID-19 antibody testing and full blood counts using hematological analyser. SARS-CoV-2 whole genome sequencing was performed using MinIon sequencing. Results The prevalence of malaria by microscopy, RDT and nested PCR were 2.3%, 2.3% and 2.7% respectively. The detection of SARS-CoV-2 by COVID-19 Rapid Antigen Test and Real-time PCR were 8.7% and 20% respectively. The Delta variant was reported in 23 of 25 SARS-CoV-2 positives with CT values below 30. Headache was the most common symptom presented by study participants (95%). Comorbidities reported were hypertension, asthma and diabetes. One hundred and thirteen (37.8%) of the study participants had prior exposure to SARS CoV-2 and (34/51) 66.7% of Astrazeneca vaccinated patients had no IgG antibody. Conclusion It may be difficult to use clinical characteristics to distinguish between patients with COVID-19 having malaria-like symptoms. Detection of IgM using RDTs may be useful in predicting CT values for SARS-CoV-2 real-time PCR and therefore transmission.
Læs mere Tjek på PubMedTuyet Kha Nguyen, Hojong Jun, Johnsy Mary Louis, Ernest Mazigo, Wang-Jong Lee, Hyun Cher Youm, Jieun Shin, Douglas K. Lungu, Creto Kanyemba, Md Atique Ahmed, Fauzi Muh, Se Jin Lee, Sunghun Na, Wanjoo Chun, Won Sun Park, Joo Hwan No, Min-Jae Kim, Eun-Taek Han, Jin-Hee Han
PLoS One Infectious Diseases, 10.02.2024
Tilføjet 10.02.2024
by Tuyet Kha Nguyen, Hojong Jun, Johnsy Mary Louis, Ernest Mazigo, Wang-Jong Lee, Hyun Cher Youm, Jieun Shin, Douglas K. Lungu, Creto Kanyemba, Md Atique Ahmed, Fauzi Muh, Se Jin Lee, Sunghun Na, Wanjoo Chun, Won Sun Park, Joo Hwan No, Min-Jae Kim, Eun-Taek Han, Jin-Hee Han Malaria eradication efforts in resource-limited areas require a rapid, economical, and accurate tool for detecting of the low parasitemia. The malaria rapid diagnostic test (mRDT) is the most suitable for on-site detection of the deadliest form of malaria, Plasmodium falciparum. However, the deletions of histidine rich protein 2 and 3 genes are known to compromise the effectiveness of mRDT. One of the approaches that have been explored intensively for on-site diagnostics is the loop-mediated isothermal amplification (LAMP). LAMP is a one-step amplification that allows the detection of Plasmodium species in less than an hour. Thus, this study aims to present a new primer set to enhance the performance of a colorimetric LAMP (cLAMP) for field application. The primer binding regions were selected within the A-type of P. falciparum 18S rRNA genes, which presents a dual gene locus in the genome. The test result of the newly designed primer indicates that the optimal reaction condition for cLAMP was 30 minutes incubation at 65°C, a shorter incubation time compared to previous LAMP detection methods that typically takes 45 to 60 minutes. The limit of detection (LoD) for the cLAMP using our designed primers and laboratory-grown P. falciparum (3D7) was estimated to be 0.21 parasites/μL which was 1,000-fold higher than referencing primers. Under optimal reaction condition, the new primer sets showed the sensitivity (100%, 95% CI: 80.49–100%) and specificity (100%, 95% CI: 94.64–100%) with 100% (95% CI: 95.70–100%) accuracy on the detection of dried blood spots from Malawi (n = 84). Briefly, the newly designed primer set for P. falciparum detection exhibited high sensitivity and specificity compared to referenced primers. One great advantage of this tool is its ability to be detected by the naked eye, enhancing field approaches. Thus, this tool has the potential to be effective for accurate early parasite detection in resource-limited endemic areas.
Læs mere Tjek på PubMedJournal of Infectious Diseases, 9.02.2024
Tilføjet 9.02.2024
Abstract Introduction Malaria is preventable yet causes >600,000 deaths annually. RTS, S, the first marketed malaria vaccine, has modest efficacy, but improvements are needed for eradication.Methods We conducted an open-label, dose escalation Phase 1 study of a recombinant, full-length circumsporozoite protein vaccine (rCSP) administered with adjuvant GLA-LSQ on days 1, 29, and 85 or 1 and 490 to healthy, malaria-naïve adults. Primary endpoints were safety and reactogenicity. Secondary endpoints were antibody responses and Plasmodium falciparum parasitemia after homologous controlled human malaria infection (CHMI).Results Participants were enrolled into four groups receiving rCSP/GLA-LSQ: 10 µg x 3 (n = 20), 30 µg x 3 (n = 10), 60 µg x 3 (n = 10) or 60 µg x 2 (n = 9); ten participants received 30 µg rCSP alone x 3; and six infectivity controls. Participants experienced no serious adverse events. Rates of solicited and unsolicited adverse events were similar among groups. All 26 participants who underwent CHMI 28 days after final vaccinations developed malaria. Increasing vaccine doses induced higher IgG titers, but did not achieve previously established RTS, S benchmarks.Conclusions rCSP/GLA-LSQ had favorable safety results. However, tested regimens did not induce protective immunity. Further investigation could assess if adjuvant or schedule adjustments improve efficacy.Trial registration ClinicalTrials.gov Identifier NCT03589794
Læs mere Tjek på PubMedThe Lancet
Lancet, 9.02.2024
Tilføjet 9.02.2024
Throughout recorded history, malaria has blighted populations across the globe. Today, by far, WHO\'s African region has the highest burden. In 2022, the region was home to 233 million (94%) malaria cases and 580 000 (95%) malaria deaths, about 80% of which were in children younger than 5 years. Despite ambitions to reduce this burden, efforts to control malaria have stagnated: global cases dropped by 29% between 2000 and 2019 but only by 2% between 2015 and 2019. Might this all be about to change? On Jan 22, 2024, Cameroon began the roll-out of RTS,S/AS01, the first malaria vaccine to be used in a national immunisation programme.
Læs mere Tjek på PubMedMehreen S Datoo, Alassane Dicko, Halidou Tinto, Jean-Bosco Ouédraogo, Mainga Hamaluba, Ally Olotu, Emma Beaumont, Fernando Ramos Lopez, Hamtandi Magloire Natama, Sophie Weston, Mwajuma Chemba, Yves Daniel Compaore, Djibrilla Issiaka, Diallo Salou, Athanase M Some, Sharon Omenda, Alison Lawrie, Philip Bejon, Harish Rao, Daniel Chandramohan, Rachel Roberts, Sandesh Bharati, Lisa Stockdale, Sunil Gairola, Brian M Greenwood, Katie J Ewer, John Bradley, Prasad S Kulkarni, Umesh Shaligram, Adrian V S Hill, R21/Matrix-M Phase 3 Trial Group
Lancet, 9.02.2024
Tilføjet 9.02.2024
R21/Matrix-M was well tolerated and offered high efficacy against clinical malaria in African children. This low-cost, high-efficacy vaccine is already licensed by several African countries, and recently received a WHO policy recommendation and prequalification, offering large-scale supply to help reduce the great burden of malaria in sub-Saharan Africa.
Læs mere Tjek på PubMedNora Schmit, Hillary M Topazian, H Magloire Natama, Duncan Bellamy, Ousmane Traoré, M Athanase Somé, Toussaint Rouamba, Marc Christian Tahita, Massa dit Achille Bonko, Aboubakary Sourabié, Hermann Sorgho, Lisa Stockdale, Samuel Provstgaard-Morys, Jeremy Aboagye, Danielle Woods, Katerina Rapi, Mehreen S Datoo, Fernando Ramos Lopez, Giovanni D Charles, Kelly McCain, Jean-Bosco Ouedraogo, Mainga Hamaluba, Ally Olotu, Alassane Dicko, Halidou Tinto, Adrian V S Hill, Katie J Ewer, Azra C Ghani, Peter Winskill
Lancet Infectious Diseases, 9.02.2024
Tilføjet 9.02.2024
Introduction of the R21/Matrix-M malaria vaccine could have a substantial public health benefit across sub-Saharan Africa.
Læs mere Tjek på PubMedMalaria Journal, 9.02.2024
Tilføjet 9.02.2024
Abstract Background Malaria is one of the most important vector-borne diseases of humans with an estimated 241 million cases worldwide in 2020. As an urban and periurban mosquito species, Anopheles stephensi is exposed to artificial human stimuli like light that can alter many aspects of mosquito behaviour, physiology and metabolism. Therefore, fluctuations in the light environment may influence the host, parasite and/or mosquito biology and hence modulate risk for disease transmission. In this study, the effect of artifitial light at night on mosquito infectivity by Plasmodium falciparum during the first hours of blood digestion was tested. Methods A total of three independent standard membrane feeding assays were performed to artificially fed septic and aseptic mosquitoes with P. falciparum infected blood. After blood feeding, females were transferred to incubators with different photoperiod cycles, so digestion occurred under day artificial light or dark. At 7 and 16 days post blood feeding, mosquitoes were dissected for midguts and salivary glands, respectively. Percentage of mosquitoes fed, percentage of prevalence and P. falciparum oocyst intensity between septic and aseptic mosquitoes in the two different photoperiod regimes, were compared using a Kruskal-Wallis test followed by a Dunn´s multiple comparison test . Results The exposition of mosquitoes to light after they took an infected blood meal has a negative effect on the successful progression of P. falciparum in the mosquito midgut. Antibiotic treatment significantly incremented the number of oocysts per midgut. Photophase significantly reduced the median oocyst intensity in both septic and aseptic mosquitoes. The percentage of oocyst reduction, understood as the percentage of reduction in the mean oocyst intensity of the parasite in the mosquito midgut between photophase and scotophase, was 51% in the case of aseptic mosquitoes and 80% for septic mosquitoes, both in the photophase condition. Conclusion Although there are still many gaps in the understanding of parasite-mosquito interactions, these results support the idea that light can, not only, influence mosquito biting behaviour but also parasite success in the mosquito midgut. Hence, light can be considered an interesting additional mosquito-control strategy to reduce mosquito-borne diseases.
Læs mere Tjek på PubMedInfection, 8.02.2024
Tilføjet 8.02.2024
Abstract Background and Objective Despite the significant burden of Plasmodium falciparum (Pf) malaria and the licensure of two vaccines for use in infants and young children that are partially effective in preventing clinical malaria caused by Pf, a highly effective vaccine against Pf infection is still lacking. Live attenuated vaccines using Pf sporozoites as the immunogen (PfSPZ Vaccines) hold promise for addressing this gap. Here we review the safety and efficacy of two of the most promising PfSPZ approaches: PfSPZ Vaccine (radiation attenuated PfSPZ) and PfSPZ-CVac (chemo-attenuated PfSPZ). Methods We conducted a systematic review and meta-analysis by searching PubMed, EMBASE, SCOPUS, CENTRAL, and WOS until 22nd December 2021. We included randomized controlled trials (RCTs) of these two vaccine approaches that measured protection against parasitaemia following controlled human malaria infection (CHMI) in malaria-naive and malaria-exposed adults or following exposure to naturally transmitted Pf malaria in African adults and children (primary outcome) and that also measured the incidence of solicited and unsolicited adverse events as indicators of safety and tolerability after vaccination (secondary outcome). We included randomized controlled trials (RCTs) that measured the detected parasitaemia after vaccination (primary outcome) and the incidence of various solicited and unsolicited adverse events (secondary outcome). The quality of the included RCTs using the Cochrane ROB 1 tool and the quality of evidence using the GRADE system were evaluated. We pooled dichotomous data using the risk ratio (RR) for development of parasitemia in vaccinees relative to controls as a measure of vaccine efficacy (VE), including the corresponding confidence interval (CI). This study was registered with PROSPERO (CRD42022308057). Results We included 19 RCTs. Pooled RR favoured PfSPZ Vaccine (RR: 0.65 with 95% CI [0.53, 0.79], P = 0.0001) and PfSPZ-table (RR: 0.42 with 95% CI [0.27, 0.67], P = 0.0002) for preventing parasitaemia, relative to normal saline placebo. Pooled RR showed no difference between PfSPZ Vaccine and the control in the occurrence of any solicited adverse event (RR: 1.00 with 95% CI [0.82, 1.23], P = 0.98), any local solicited adverse events (RR: 0.73 with 95% CI [0.49, 1.08], P = 0.11), any systemic solicited adverse events (RR: 0.94 with 95% CI [0.75, 1.17], P = 0.58), and any unsolicited adverse event (RR: 0.93 with 95% CI [0.78, 1.10], P = 0.37). Conclusion PfSPZ and PfSPZ-CVacs showed comparable efficacy. Therefore, they can introduce a promising strategy for malaria prophylaxis, but more large-scale field trials are required to sustain efficacy and yield clinically applicable findings.
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 8.02.2024
Tilføjet 8.02.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 2 Pages: 202-208
Læs mere Tjek på PubMedAmerican Journal of Tropical Medicine and Hygiene, 8.02.2024
Tilføjet 8.02.2024
Journal Name: The American Journal of Tropical Medicine and Hygiene Volume: 110 Issue: 2 Pages: 214-219
Læs mere Tjek på PubMedBMC Infectious Diseases, 8.02.2024
Tilføjet 8.02.2024
Abstract Background In Burkina Faso, the prevalence of malaria has decreased over the past two decades, following the scale-up of control interventions. The successful development of malaria parasites depends on several climatic factors. Intervention gains may be reversed by changes in climatic factors. In this study, we investigated the role of malaria control interventions and climatic factors in influencing changes in the risk of malaria parasitaemia. Methods Bayesian logistic geostatistical models were fitted on Malaria Indicator Survey data from Burkina Faso obtained in 2014 and 2017/2018 to estimate the effects of malaria control interventions and climatic factors on the temporal changes of malaria parasite prevalence. Additionally, intervention effects were assessed at regional level, using a spatially varying coefficients model. Results Temperature showed a statistically important negative association with the geographic distribution of parasitaemia prevalence in both surveys; however, the effects of insecticide-treated nets (ITNs) use was negative and statistically important only in 2017/2018. Overall, the estimated number of infected children under the age of 5 years decreased from 704,202 in 2014 to 290,189 in 2017/2018. The use of ITNs was related to the decline at national and regional level, but coverage with artemisinin-based combination therapy only at regional level. Conclusion Interventions contributed more than climatic factors to the observed change of parasitaemia risk in Burkina Faso during the period of 2014 to 2017/2018. Intervention effects varied in space. Longer time series analyses are warranted to determine the differential effect of a changing climate on malaria parasitaemia risk.
Læs mere Tjek på PubMedPhilip J. Rosenthal, Victor Asua, Melissa D. Conrad
Nat Rev Microbiol, 7.02.2024
Tilføjet 7.02.2024
Malaria Journal, 6.02.2024
Tilføjet 6.02.2024
Abstract Background An estimated 50% of suspected malaria cases in sub-Saharan Africa first seek care in the private sector, especially in private medicine retail outlets. Quality of care in these outlets is generally unknown but considered poor with many patients not receiving a confirmatory diagnosis or the recommended first-line artemisinin-based combination therapy (ACT). In 2010, a subsidy pilot scheme, the Affordable Medicines Facility malaria, was introduced to crowd out the use of monotherapies in favour of WHO-pre-qualified artemisinin-based combinations (WHO-PQ-ACTs) in the private health sector. The scheme improved the availability, market share, and cost of WHO-PQ-ACTs in countries like Nigeria and Uganda, but in 2018, the subsidies were halted in Nigeria and significantly reduced in Uganda. This paper presents findings from six retail audit surveys conducted from 2014 to 2021 in Nigeria and Uganda to assess whether the impact of subsidies on the price, availability, and market share of artemisinin-based combinations has been sustained after the subsidies were reduced or discontinued. Methods Six independent retail audits were conducted in private medicine retail outlets, including pharmacies, drug shops, and clinics in Nigeria (2016, 2018, 2021), and Uganda (2014, 2019, 2020) to assess the availability, price, and market share of anti-malarials, including WHO-PQ-ACTs and non-WHO-PQ-ACTs, and malaria rapid diagnostic tests (RDTs). Results Between 2016 and 2021, there was a 57% decrease in WHO-PQ-ACT availability in Nigeria and a 9% decrease in Uganda. During the same period, non-WHO-PQ-ACT availability increased in Nigeria by 41% and by 34% in Uganda. The price of WHO-PQ-ACTs increased by 42% in Nigeria to $0.68 and increased in Uganda by 24% to $0.95. The price of non-WHO-PQ-ACTs decreased in Nigeria by 26% to $1.08 and decreased in Uganda by 64% to $1.23. There was a 76% decrease in the market share of WHO-PQ-ACTs in Nigeria and a 17% decrease in Uganda. Malaria RDT availability remained low throughout. Conclusion With the reduction or termination of subsidies for WHO-PQ-ACTs in Uganda and Nigeria, retail prices have increased, and retail prices of non-WHO-PQ-ACTs decreased, likely contributing to a shift of higher availability and increased use of non-WHO-PQ-ACTs.
Læs mere Tjek på PubMedMalaria Journal, 6.02.2024
Tilføjet 6.02.2024
Abstract Background Artemisinin-based combination therapy (ACT) has been effective in the supervised treatment of uncomplicated malaria in Ghana. Since ACT usage is primarily unsupervised, this study aimed to determine the effectiveness of artemether–lumefantrine (AL) for treating malaria patients in two transmission settings in Ghana. Methods Eighty-four individuals with uncomplicated Plasmodium falciparum malaria were recruited from Lekma Hospital (LH) in Accra (low-transmission area; N = 28), southern Ghana, and King’s Medical Centre (KMC) in Kumbungu (high-transmission area; N = 56), northern Ghana. Participants were followed up for 28 days after unsupervised treatment with AL. The presence of asexual parasites was determined by microscopic examination of Giemsa-stained blood smears. Plasmodium species identification was confirmed using species-specific primers targeting the 18S rRNA gene. Parasite recrudescence or reinfection was determined by genotyping the Pfmsp 1 and Pfmsp 2 genes. Results After AL treatment, 3.6% (2/56) of the patients from KMC were parasitaemic on day 3 compared to none from the LH patients. One patient from KMC with delayed parasite clearance on day 3 remained parasite-positive by microscopy on day 7 but was parasite-free by day 14. While none of the patients from LH experienced parasite recurrence during the 28-day follow-up, three and two patients from KMC had recurrent parasitaemia on days 21 and 28, respectively. Percentage reduction in parasite densities from day 1, 2, and 3 for participants from the KMC was 63.2%, 89.5%, and 84.5%. Parasite densities for participants from the LH reduced from 98.2%, 99.8% on day 1, and 2 to 100% on day 3. The 28-day cumulative incidence rate of treatment failure for KMC was 12.8% (95% confidence interval: 1.9–23.7%), while the per-protocol effectiveness of AL in KMC was 89.47%. All recurrent cases were assigned to recrudescence after parasite genotyping by Pfmsp 1 and Pfmsp 2. Conclusion While AL is efficacious in treating uncomplicated malaria in Ghana, when taken under unsupervised conditions, it showed an 89.4% PCR-corrected cure rate in northern Ghana, which is slightly below the WHO-defined threshold.
Læs mere Tjek på PubMedInfection, 6.02.2024
Tilføjet 6.02.2024
Abstract Background and Objective Despite the significant burden of Plasmodium falciparum (Pf) malaria and the licensure of two vaccines for use in infants and young children that are partially effective in preventing clinical malaria caused by Pf, a highly effective vaccine against Pf infection is still lacking. Live attenuated vaccines using Pf sporozoites as the immunogen (PfSPZ Vaccines) hold promise for addressing this gap. Here we review the safety and efficacy of two of the most promising PfSPZ approaches: PfSPZ Vaccine (radiation attenuated PfSPZ) and PfSPZ-CVac (chemo-attenuated PfSPZ). Methods We conducted a systematic review and meta-analysis by searching PubMed, EMBASE, SCOPUS, CENTRAL, and WOS until 22nd December 2021. We included randomized controlled trials (RCTs) of these two vaccine approaches that measured protection against parasitaemia following controlled human malaria infection (CHMI) in malaria-naive and malaria-exposed adults or following exposure to naturally transmitted Pf malaria in African adults and children (primary outcome) and that also measured the incidence of solicited and unsolicited adverse events as indicators of safety and tolerability after vaccination (secondary outcome). We included randomized controlled trials (RCTs) that measured the detected parasitaemia after vaccination (primary outcome) and the incidence of various solicited and unsolicited adverse events (secondary outcome). The quality of the included RCTs using the Cochrane ROB 1 tool and the quality of evidence using the GRADE system were evaluated. We pooled dichotomous data using the risk ratio (RR) for development of parasitemia in vaccinees relative to controls as a measure of vaccine efficacy (VE), including the corresponding confidence interval (CI). This study was registered with PROSPERO (CRD42022308057). Results We included 19 RCTs. Pooled RR favoured PfSPZ Vaccine (RR: 0.65 with 95% CI [0.53, 0.79], P = 0.0001) and PfSPZ-table (RR: 0.42 with 95% CI [0.27, 0.67], P = 0.0002) for preventing parasitaemia, relative to normal saline placebo. Pooled RR showed no difference between PfSPZ Vaccine and the control in the occurrence of any solicited adverse event (RR: 1.00 with 95% CI [0.82, 1.23], P = 0.98), any local solicited adverse events (RR: 0.73 with 95% CI [0.49, 1.08], P = 0.11), any systemic solicited adverse events (RR: 0.94 with 95% CI [0.75, 1.17], P = 0.58), and any unsolicited adverse event (RR: 0.93 with 95% CI [0.78, 1.10], P = 0.37). Conclusion PfSPZ and PfSPZ-CVacs showed comparable efficacy. Therefore, they can introduce a promising strategy for malaria prophylaxis, but more large-scale field trials are required to sustain efficacy and yield clinically applicable findings.
Læs mere Tjek på PubMedMalaria Journal, 3.02.2024
Tilføjet 3.02.2024
Abstract Background Seasonal Malaria Chemoprevention (SMC) is a highly effective intervention for preventing malaria, particularly in areas with highly seasonal transmission. Monitoring and evaluating (M&E) SMC programmes are complex due to the scale, time-sensitive delivery of the programme, and influence of external factors. This paper describes the process followed to develop a comprehensive M&E framework tailored specifically for the SMC context. Methods The Framework was developed through a literature and programme review, and stakeholder dialogues across three implementing countries—Burkina Faso, Chad, and Nigeria. Expert consultation further refined the Framework through an iterative approach drawing upon data collected through the three sources. The Framework was designed using the Logical Framework Approach incorporating external factors and intentionally aligned with global malaria M&E standards. Results An overall aim and seven programme objectives were developed measured by 70 indicators. The indicators also capture the causal links between the implementation and results of the programme. The Framework leverages the use of current data sources and existing mechanisms, ensuring efficient data use without requiring a significant increase in resources for overall programme optimization. It also promotes the use of data triangulation, and stratification for a more nuanced understanding of factors affecting programme performance and timely data informed decision-making. Conclusions The SMC M&E Framework presented here provides a standardized approach for programme implementers to enhance decision-making for optimal programme performance. This is an essential tool as the scope of SMC programmes expands to new geographies and target age groups.
Læs mere Tjek på PubMedMalaria Journal, 3.02.2024
Tilføjet 3.02.2024
Abstract Background It was hypothesized that glucose-6-phosphate dehydrogenase (G6PD) deficiency confers a protective effect against malaria infection, however, safety concerns have been raised regarding haemolytic toxicity caused by radical cure with 8-aminoquinolines in G6PD-deficient individuals. Malaria elimination and control are also complicated by the high prevalence of G6PD deficiency in malaria-endemic areas. Hence, accurate identification of G6PD deficiency is required to identify those who are eligible for malaria treatment using 8-aminoquinolines. 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.
Læs mere Tjek på PubMedJournal of Infectious Diseases, 2.02.2024
Tilføjet 2.02.2024
Abstract PfGARP is a recently characterized cell surface antigen encoded by Plasmodium falciparum, the causative agent of severe human malaria pathophysiology. Previously, we reported that the human erythrocyte band 3 (SLC4A1) serves as a host receptor for PfGARP. Antibodies against PfGARP did not affect parasite invasion and growth. We surmised that PfGARP may play a role in the rosetting and adhesion of malaria. Another study reported that antibodies targeting PfGARP exhibit potent inhibition of parasite growth. This inhibition occurred without the presence of any immune or complement components, suggesting the activation of an inherent density-dependent regulatory system. Here, we used polyclonal antibodies against PfGARP and a monoclonal antibody mAb78993 to demonstrate that anti-PfGARP polyclonal antibodies, but not mAb7899, exerted potent inhibition of parasite growth in infected erythrocytes independent of PfGARP. These findings suggest that an unknown malaria protein(s) is the target of growth arrest by polyclonal antibodies raised against PfGARP.
Læs mere Tjek på PubMedPaul Adepoju
Lancet, 2.02.2024
Tilføjet 2.02.2024
Starting in Cameroon, over 3 million children in 20 countries are due to receive malaria vaccination in 2024. Paul Adepoju reports.
Læs mere Tjek på PubMedNora CéspedesErinn L. DonnellyGretchen HanstenAbigail M. FellowsMegan DobsonHannah L. KaylorTaylor A. ColesJoseph SchauerJudy Van de WaterShirley Luckhart1Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, Idaho, USA2Department of Biological Sciences, University of Idaho, Moscow, Idaho, USA3Division of Rheumatology, Allergy and Clinical Immunology, University of California, Davis, California, USA, De'Broski R. Herbert
Infection and Immunity, 2.02.2024
Tilføjet 2.02.2024
BMC Infectious Diseases, 2.02.2024
Tilføjet 2.02.2024
Abstract Background Previous studies show increased morbidity in children who are HIV-exposed but uninfected (HEU) compared to children who are HIV-unexposed uninfected (HUU). We sought to evaluate the effects of prenatal HIV exposure on clinical and immunological outcomes in the first 24 months of life. Methods Eighty-five HEU and 168 HUU children from Kenya were followed from birth to 24 months. All mothers living with HIV received combination antiretroviral therapy. Children who were HEU received standard-of-care cotrimoxazole prophylaxis through 18 months. Episodes of acute illness were identified through a combination of active and passive follow up. Trajectories of plasma cytokines, vaccine-specific antibodies, and antimalarial antibodies were examined. Results Children who were HEU and children who were HUU had similar growth curves. Children who were HEU had lower rates of malaria (rate ratio 0.54, 95% CI 0.38, 0.77) and respiratory illness (rate ratio 0.80, 95% CI 0.68, 0.93). Trajectories of plasma cytokines and vaccine-specific antibodies were similar in children who were HEU and HUU. There were subtle differences in antimalarial antibody dynamics, in which children who were HEU had overall lower antibody levels against five of the 14 malaria antigens tested. Conclusions Children who were HEU and born to optimally treated mothers living with HIV had similar growth characteristics and immune profiles compared to children who were HUU. Children who were HEU had reduced risk for malaria and respiratory illness, which may be secondary to cotrimoxazole prophylaxis.
Læs mere Tjek på PubMedSeong-Kyun LeeCécile CrosnierPaola Carolina Valenzuela-LeonBrian L. P. DizonJohn P. AtkinsonJianbing MuGavin J. WrightEric CalvoKarthigayan GunalanLouis H. MilleraLaboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852bDepartment of Biology, Hull York Medical School, York Biomedical Research Institute, University of York, York YO10 5DD, United KingdomcLaboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852dRheumatology Fellowship Training Program, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, MD 20892eDivision of Rheumatology, Department of Medicine, Washington University School of Medicine, Saint Louis, MO 63110
Proceedings of the National Academy of Sciences, 31.01.2024
Tilføjet 31.01.2024
Proceedings of the National Academy of Sciences, Volume 121, Issue 5, January 2024.
Læs mere Tjek på PubMedMalaria Journal, 30.01.2024
Tilføjet 30.01.2024
Abstract Background A major challenge to malaria elimination is identifying and targeting populations that are harbouring residual infections and contributing to persistent transmission. In many near-elimination settings in Southeast Asia, it is known that forest-goers are at higher risk for malaria infection, but detailed information on their behaviours and exposures is not available. Methods In Aceh Province, Indonesia, a near-elimination setting where a growing proportion of malaria is due to Plasmodium knowlesi, a case–control study was conducted to identify risk factors for symptomatic malaria, characteristics of forest-goers, and key intervention points. From April 2017 to September 2018, cases and controls were recruited and enrolled in a 1:3 ratio. Cases had confirmed malaria infection by rapid diagnostic test or microscopy detected at a health facility (HF). Gender-matched controls were recruited from passive case detection among individuals with suspected malaria who tested negative at a health facility (HF controls), and community-matched controls were recruited among those testing negative during active case detection. Multivariable logistic regression (unconditional for HF controls and conditional for community controls) was used to identify risk factors for symptomatic malaria infection. Results There were 45 cases, of which 27 were P. knowlesi, 17 were Plasmodium vivax, and one was not determined. For controls, 509 and 599 participants were recruited from health facilities and the community, respectively. Forest exposures were associated with high odds of malaria; in particular, working and sleeping in the forest (HF controls: adjusted odds ratio (aOR) 21.66, 95% CI 5.09–92.26; community controls: aOR 16.78, 95% CI 2.19–128.7) and having a second residence in the forest (aOR 6.29, 95% CI 2.29–17.31 and 13.53, 95% CI 2.10–87.12). Male forest-goers were a diverse population employed in a variety of occupations including logging, farming, and mining, sleeping in settings, such as huts, tents, and barracks, and working in a wide range of group sizes. Reported use of protective measures, such as nets, hammock nets, mosquito coils, and repellents was low among forest-goers and interventions at forest residences were absent. Conclusions Second residences in the forest and gaps in use of protective measures point to key malaria interventions to improve coverage in forest-going populations at risk for P. knowlesi and P. vivax in Aceh, Indonesia. Intensified strategies tailored to specific sub-populations will be essential to achieve elimination.
Læs mere Tjek på PubMedGeetha P. BansalMaisa da Silva AraujoYi CaoEmily ShafferJessica Evangelista AraujoJansen Fernandes MedeirosClifford HayashiJoseph VinetzNirbhay Kumar1Department of Tropical Medicine, Tulane University, New Orleans, Louisiana, USA2Plataforma de Produção e Infecção de Vetores da Malária, Laboratório de Entomologia - Fiocruz Rondônia, Porto Velho, Rondônia, Brazil3Department of Global Health, George Washington University, Washington, DC, USA4Programa de Pós-Graduação em Biologia Experimental, Fundação Universidade Federal de Rondônia, Fiocruz Rondônia, Porto Velho, Rondônia, Brazil5Yale School of Medicine, New Haven, Connecticut, USA, Jeroen P. J. Saeij
Infection and Immunity, 30.01.2024
Tilføjet 30.01.2024
BMC Infectious Diseases, 30.01.2024
Tilføjet 30.01.2024
Abstract Background Cumulative malaria parasite exposure in endemic regions often results in the acquisition of partial immunity and asymptomatic infections. There is limited information on how host-parasite interactions mediate the maintenance of chronic symptomless infections that sustain malaria transmission. Methods Here, we determined the gene expression profiles of the parasite population and the corresponding host peripheral blood mononuclear cells (PBMCs) from 21 children (
Læs mere Tjek på PubMedMalaria Journal, 30.01.2024
Tilføjet 30.01.2024
Abstract Background Timely molecular surveillance of Plasmodium falciparum kelch 13 (k13) gene mutations is essential for monitoring the emergence and stemming the spread of artemisinin resistance. Widespread artemisinin resistance, as observed in Southeast Asia, would reverse significant gains that have been made against the malaria burden in Africa. The purpose of this study was to assess the prevalence of k13 polymorphisms in western Kenya and Ethiopia at sites representing varying transmission intensities between 2018 and 2022. Methods Dried blood spot samples collected through ongoing passive surveillance and malaria epidemiological studies, respectively, were investigated. The k13 gene was genotyped in P. falciparum isolates with high parasitaemia: 775 isolates from four sites in western Kenya (Homa Bay, Kakamega, Kisii, and Kombewa) and 319 isolates from five sites across Ethiopia (Arjo, Awash, Gambella, Dire Dawa, and Semera). DNA sequence variation and neutrality were analysed within each study site where mutant alleles were detected. Results Sixteen Kelch13 haplotypes were detected in this study. Prevalence of nonsynonymous k13 mutations was low in both western Kenya (25/783, 3.19%) and Ethiopia (5/319, 1.57%) across the study period. Two WHO-validated mutations were detected: A675V in three isolates from Kenya and R622I in four isolates from Ethiopia. Seventeen samples from Kenya carried synonymous mutations (2.17%). No synonymous mutations were detected in Ethiopia. Genetic variation analyses and tests of neutrality further suggest an excess of low frequency polymorphisms in each study site. Fu and Li’s F test statistic in Semera was 0.48 (P > 0.05), suggesting potential population selection of R622I, which appeared at a relatively high frequency (3/22, 13.04%). Conclusions This study presents an updated report on the low frequency of k13 mutations in western Kenya and Ethiopia. The WHO-validated R622I mutation, which has previously only been reported along the north-west border of Ethiopia, appeared in four isolates collected from eastern Ethiopia. The rapid expansion of R622I across Ethiopia signals the need for enhanced monitoring of the spread of drug-resistant P. falciparum parasites in East Africa. Although ACT remains currently efficacious in the study areas, continued surveillance is necessary to detect early indicators of artemisinin partial resistance.
Læs mere Tjek på PubMedJournal of Infectious Diseases, 29.01.2024
Tilføjet 29.01.2024
Abstract Background Transcriptomics has been used to evaluate immune responses during malaria in diverse cohorts worldwide. However, the high heterogeneity of cohorts and poor generalization of transcriptional signatures reported in each study limit their potential clinical applications.Methods We compiled 28 public datasets containing 1,556 whole blood or peripheral blood mononuclear cells (PBMC) transcriptome samples. We estimated effect sizes with Hedges´ g and DerSimonian-Laird random effects model for meta-analyses of uncomplicated malaria. Random forest models identified gene signatures that discriminate malaria from bacterial infections or malaria severity. Parasitological, hematological, immunological, and metabolomics data were used for validation.Results We identified three gene signatures denominated the uncomplicated Malaria Meta-Signature (uMMS), which discriminates P. falciparum malaria from uninfected controls; the Malaria or Bacteria Signature (MoBS), that distinguishes malaria from sepsis and enteric fever; and the cerebral Malaria Meta-Signature (cMMS), which characterizes individuals with cerebral malaria. These signatures correlate with clinical hallmark features of malaria. Blood transcription modules (BTM) indicate immune regulation by glucocorticoids, whereas cell development and adhesion are associated with cerebral malaria.Conclusion Transcriptional meta-signatures reflecting immune cell responses provide potential biomarkers for translational innovation and suggest critical roles for metabolic regulators of inflammation during malaria.
Læs mere Tjek på PubMedMalaria Journal, 28.01.2024
Tilføjet 28.01.2024
Abstract Background Sri Lanka after eliminating malaria in 2012, is in the prevention of re-establishment (POR) phase. Being a tropical country with high malariogenic potential, maintaining vigilance is important. All malaria cases are investigated epidemiologically and followed up by integrated drug efficacy surveillance (iDES). Occasionally, that alone is not adequate to differentiate Plasmodium falciparum reinfections from recrudescences. This study evaluated the World Health Organization and Medicines for Malaria Venture (MMV) recommended genotyping protocol for the merozoite surface proteins (msp1, msp2) and the glutamate-rich protein (glurp) to discriminate P. falciparum recrudescence from reinfection in POR phase. Methods All P. falciparum patients detected from April 2014 to December 2019 were included in this study. Patients were treated and followed up by iDES up to 28 days and were advised to get tested if they develop fever at any time over the following year. Basic socio-demographic information including history of travel was obtained. Details of the malariogenic potential and reactive entomological and parasitological surveillance carried out by the Anti Malaria Campaign to exclude the possibility of local transmission were also collected. The msp1, msp2, and glurp genotyping was performed for initial and any recurrent infections. Classification of recurrent infections as recrudescence or reinfection was done based on epidemiological findings and was compared with the genotyping outcome. Results Among 106 P. falciparum patients, six had recurrent infections. All the initial infections were imported, with a history of travel to malaria endemic countries. In all instances, the reactive entomological and parasitological surveillance had no evidence for local transmission. Five recurrences occurred within 28 days of follow-up and were classified as recrudescence. They have not travelled to malaria endemic countries between the initial and recurrent infections. The other had a recurrent infection after 105 days. It was assumed a reinfection, as he had travelled to the same malaria endemic country in between the two malaria attacks. Genotyping confirmed the recrudescence and the reinfection. Conclusions The msp1, msp2 and glurp genotyping method accurately differentiated reinfections from recrudescence. Since reinfection without a history of travel to a malaria endemic country would mean local transmission, combining genotyping outcome with epidemiological findings will assist classifying malaria cases without any ambiguity.
Læs mere Tjek på PubMedGilbert Nakweya
Lancet, 26.01.2024
Tilføjet 26.01.2024
It is just the third African country to eliminate the disease, following years of concerted effort to enhance diagnosis, treatment, and surveillance. Gilbert Nakweya reports.
Læs mere Tjek på PubMedHellen C Barsosio, Mwayiwawo Madanitsa, Everlyne D Ondieki, James Dodd, Eric D Onyango, Kephas Otieno, Duolao Wang, Jenny Hill, Victor Mwapasa, Kamija S Phiri, Kenneth Maleta, Miriam Taegtmeyer, Simon Kariuki, Christentze Schmiegelow, Julie R Gutman, Feiko O ter Kuile
Lancet, 26.01.2024
Tilføjet 26.01.2024
Addition of monthly intermittent preventive treatment with dihydroartemisinin–piperaquine to the standard of care with daily unsupervised co-trimoxazole in areas of high antifolate resistance substantially improves malaria chemoprevention in pregnant women living with HIV on dolutegravir-based cART and should be considered for policy.
Læs mere Tjek på PubMedMalaria Journal, 25.01.2024
Tilføjet 25.01.2024
Abstract The emergence and spread of artemisinin partial resistance in East and Horn of Africa is alarming. However, artemisinin-based combination therapy (ACT) generally remains efficacious for the treatment of falciparum malaria. The emergence of partial artemisinin resistance does not currently meet the criteria to initiate change on treatment guidelines nor affect ACT routine procurement and distribution. It is high time for scientists and transitional researchers to be more critical and vigilant on further changes so that national programmes will be able to make informed decisions as well as remain alert and prepared for any change that may be required in the future.
Læs mere Tjek på PubMedGeorges Snounou, Paul M. Sharp, Richard Culleton
Trends in Parasitology, 25.01.2024
Tilføjet 25.01.2024
Our recent article [1] reviewed the history of the human malaria parasite Plasmodium ovale from its original discovery to the realisation that it comprises two morphologically cryptic species that are genetically quite divergent. We ended with a proposal that the trinomial names that have been used for these two species over the past 14 years be replaced. Šlapeta, Sutherland and Fuehrer [2] concur with this, but object to the names we have proposed. They contend that we have not followed the rules of the International Code for Zoological Nomenclature (ICZN) [3], insofar as (i) we have not lodged a ‘type’ (in the form of a blood smear) for each of the species, and (ii) we have not retained the original name (P.
Læs mere Tjek på PubMedMalaria Journal, 24.01.2024
Tilføjet 24.01.2024
Abstract Background Seasonal malaria chemoprevention (SMC) is an effective intervention to prevent malaria in children in locations where the burden of malaria is high and transmission is seasonal. There is growing evidence suggesting that SMC with sulfadoxine–pyrimethamine and amodiaquine can retain its high level of effectiveness in East and Southern Africa despite resistance concerns. This study aims to generate evidence on the effectiveness of SMC when delivered under programmatic conditions in an area with an unknown anti-malarial drug resistance profile in the Northern Bahr el-Ghazal region of South Sudan. Methods A non-randomized quasi experimental study was conducted to compare an intervention county with a control county. Five monthly SMC cycles were delivered between July and November 2022, targeting about 19,000 children 3–59 months old. Data were obtained from repeated cross-sectional household surveys of caregivers of children aged 3–59 months using cluster sampling. Wave 1 survey took place in both counties before SMC implementation; Waves 2 and 3 took place after the second and fourth monthly SMC cycles. Difference-in-differences analyses were performed by fitting logistic regression models with interactions between county and wave. Results A total of 2760 children were sampled in the study across the three survey waves in both study counties. Children in the intervention arm had 70% lower odds of caregiver-reported fever relative to those in the control arm during the one-month period prior to Wave 2 (OR: 0.30, 95% CI 0.12–0.70, p = 0.003), and 37% lower odds in Wave 3 (OR: 0.63, 95% CI 0.22–1.59, p = 0.306) after controlling for baseline difference between counties in Wave 1. Odds of caregiver-reported RDT-confirmed malaria were 82% lower in the previous 1-month period prior to Wave 2 (OR: 0.18, 95% CI 0.07–0.49, p = 0.001) and Wave 3 (OR: 0.18, 95% CI 0.06–0.54, p = 0.003). Conclusion These results show high effectiveness of SMC using SPAQ in terms of reducing malaria disease during the high transmission season in children 3–59 month. Despite the promising results, additional evidence and insights from chemoprevention efficacy cohort studies, and analyses of relevant resistance markers, are required to assess the suitability of SMC for this specific context.
Læs mere Tjek på PubMedMalaria Journal, 24.01.2024
Tilføjet 24.01.2024
Abstract Background Despite Ethiopia’s concerted efforts to eliminate malaria by 2030, the disease continues to pose a significant public health and socioeconomic challenge in the country. The year 2021 witnessed 2.78 million malaria cases and 8041 associated deaths, emphasizing the persistent threat. Monitoring the prevalence trend of malaria is crucial for devising effective control and elimination strategies. This study aims to assess the trend of malaria prevalence at the Metehara Health Centre in the East Shoa Zone, Ethiopia. Methods A retrospective study, spanning from February to September 2023, utilized malaria registration laboratory logbooks at Metehara Health Centre to evaluate the prevalence of malaria from 2017/18 to 2022/23. Malaria and related data were collected using a pre-designed data collection sheet. Descriptive statistics were employed for data summarization, presented through graphs and tables. Results Out of 59,250 examined blood films, 17.4% confirmed the presence of Plasmodium infections. Among the confirmed cases, 74.3%, 23.8%, and 1.84% were attributed to Plasmodium falciparum, Plasmodium vivax, and mixed infections, respectively. The trend of malaria exhibited a steady decline from 2017/18 to 2021/22, reaching 9.8% prevalence. However, an abrupt increase to 26.5% was observed in 2022/23. Males accounted for a higher proportion (66%) of cases compared to females (34%). The age group 15–24 years experienced the highest malaria incidence at 42%. Notably, malaria cases peaked during autumn (September to November) at 43% and reached the lowest percentage during spring (March to May) at 13%. Conclusion Malaria persists as a significant health challenge in and around Metehara, central Ethiopia, predominantly driven by Plasmodium falciparum. The five-year declining trend was interrupted by a notable upsurge in 2022/23, indicating a resurgence of malaria in the study area. It is imperative to adopt a reverse strategy to sustain the progress achieved by the national malaria control plan.
Læs mere Tjek på PubMedNicola GreylingMariëtte van der WattHazel GwarindaAshleigh van HeerdenBryan GreenhouseDidier LeroyJandeli NiemandLyn-Marié Birkholtz1Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa2Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa3Department of Medicine, University of California-San Francisco, San Francisco, California, USA4Medicines for Malaria Venture, Geneva, Switzerland, Audrey Odom John
Antimicrobial Agents And Chemotherapy, 23.01.2024
Tilføjet 23.01.2024
D. Channe Gowda, Louis H. Miller
Trends in Parasitology, 23.01.2024
Tilføjet 23.01.2024
In malaria parasites, although post-translational modification of proteins with N-. O-, and C-glycosidic bond-linked glycans is limited, it is confined to relatively fewer proteins in which the glycans are present at significant levels and may have important functions. Furthermore, several proteins are modified with glycosylphosphatidylinositols (GPIs) which represent the predominant glycan synthesized by parasites. Modification of proteins with GPIs is obligatory for parasite survival as GPI-anchored proteins play essential roles in all life cycle stages of the parasites, including development, egress, gametogenesis, motility, and host cell adhesion and invasion. Here, we discuss the current knowledge on the structures and potential functions of the glycan moieties of parasite proteins. The knowledge has important implications for the development of drugs and vaccines for malaria.
Læs mere Tjek på PubMedMalaria Journal, 23.01.2024
Tilføjet 23.01.2024
Abstract Background The emergence of insecticide resistance and outdoor transmission in malaria-endemic areas underlines the urgent need to develop innovative tools, such as spatial repellents (SR), that may circumvent this residual transmission. With limited options for effective insecticides, regular resistance monitoring is warranted for selecting and using appropriate tools. This study evaluates the pyrethroid knockdown resistance (kdr) allele before and after implementing a transfluthrin-based spatial repellent (SR) intervention in placebo-treated clusters. Methods This study looks at the frequency distribution of the kdr allele in Sumba Island from June 2015 to August 2018. Insecticide susceptibility tests were carried out on female Anopheles sp. aged 3–5 days against permethrin 21.5 μg/ml, deltamethrin 12.5 μg/ml, and transfluthrin 10 μg/ml using CDC bottle assay. PCR sequencing of representative samples from adult mosquito collections and insecticide tests revealed the presence of kdr mutations (L1014F and L1014S) in the VGSC gene. Results A total of 12 Anopheles species, Anopheles tesselatus, Anopheles. aconitus, Anopheles barbirostris, Anopheles kochi, Anopheles annularis, Anopheles maculatus, Anopheles sundaicus, Anopheles flavirostris, Anopheles balabacensis, Anopheles indefinitus, Anopheles subpictus, and Anopheles vagus were analysed. Anopheles vagus and An. sundaicus predominated in the larval populations. Susceptibility assays for all insecticides identified fully susceptible phenotypes in all species examined. Anopheles increasing frequency of kdr mutant alleles during the 3 year SR deployment was observed in both SR-treated and placebo areas, a statistically significant increase occurred in each arm. However, it is unclear how significant SR is in causing the increase in mutant alleles. The L1014S, knockdown resistance east type (kdr-e) allele was detected for the first time among the mosquito samples in this study. The L1014F, knockdown resistance west type (kdr-w) allele and heteroduplex form (wild-type—mutant) were found in almost all Anopheles species examined, including An. vagus, An. aconitus, An. subpictus, An. tesselatus, An. annularis, An. flavirostris and An. sundaicus. Conclusion The presence of fully susceptible phenotypes over time, along with an increase in the frequency distribution of the L1014F/S mutations post-intervention, suggest drivers of resistance external to the study, including pyrethroid use in agriculture and long-lasting insecticidal nets (LLINs). However, this does not negate possible SR impacts that support resistance. More studies that enable the comprehension of possible SR-based drivers of resistance in mosquitoes need to be conducted.
Læs mere Tjek på PubMedMalaria Journal, 19.01.2024
Tilføjet 19.01.2024
Abstract Background In children with cerebral malaria (CM) admission blood lactate has previously guided intravenous fluid therapy and been validated as a prognostic biomarker associated with death. The usefulness of post-admission measurements of blood lactate in children with CM is less clear. The strength of association between blood lactate and neurological sequelae in CM survivors, as well as the optimal duration of post-admission measurements of blood lactate to identify children at higher risk of adverse outcomes is unknown. Methods A retrospective cohort study of 1674 Malawian children with CM hospitalized from 2000 to 2018 who had blood lactate measurements every 6 h for the first 24 h after admission was performed. The strength of association between admission lactate or values measured at any time point in the first 24 h post-admission and outcomes (mortality and neurological morbidity in survivors) was estimated. The duration of time after admission that lactate remained a valid prognostic biomarker was assessed. Results When lactate is analysed as a continuous variable, children with CM who have higher values at admission have a 1.05-fold higher odds (95% CI 0.99–1.11) of death compared to those with lower lactate values. Children with higher blood lactate at 6 h have 1.16-fold higher odds (95% CI 1.09–1.23) of death, compared to those with lower values. If lactate levels are dichotomized into hyperlactataemic (lactate > 5.0 mmol/L) or not, the strength of association between admission lactate and mortality increases (OR = 2.49, 95% CI 1.47–4.22). Blood lactate levels obtained after 18 h post-admission are not associated with outcomes. Similarly, the change in lactate concentrations through time during the first 24 h of hospital admission is not associated with outcomes. Blood lactate during hospitalization is not associated with adverse neurologic outcomes in CM survivors. Conclusions In children with CM, blood lactate is associated with death but not neurologic morbidity in survivors. To comprehensively estimate prognosis, blood lactate in children with CM should be assessed at admission and for 18 h afterwards.
Læs mere Tjek på PubMedMalaria Journal, 19.01.2024
Tilføjet 19.01.2024
Abstract Background In 2015, Tanzania National Malaria Control Programme (NMCP) established a longitudinal malaria vector entomological surveillance (MVES). The MVES is aimed at a periodical assessment of malaria vector composition and abundance, feeding and resting behaviours, and Plasmodium falciparum infection in different malaria epidemiological strata to guide the NMCP on the deployment of appropriate malaria vector interventions. This work details the dynamics of malaria vector composition and transmission in different malaria epidemiological strata. Methods The MVES was conducted from 32 sentinel district councils across the country. Mosquitoes were collected by the trained community members and supervised by the NMCP and research institutions. Three consecutive night catches (indoor collection with CDC light trap and indoor/outdoor collection using bucket traps) were conducted monthly in three different households selected randomly from two to three wards within each district council. Collected mosquitoes were sorted and morphologically identified in the field. Thereafter, the samples were sent to the laboratory for molecular characterization using qPCR for species identification and detection of P. falciparum infections (sporozoites). ELISA technique was deployed for blood meal analysis from samples of blood-fed mosquitoes to determine the blood meal indices (BMI). Results A total of 63,226 mosquitoes were collected in 32 district councils from January 2017 to December 2021. Out of which, 39,279 (62%), 20,983 (33%) and 2964 (5%) were morphologically identified as Anopheles gambiae sensu lato (s.l.), Anopheles funestus s.l., and as other Anopheles species, respectively. Out of 28,795 laboratory amplified mosquitoes, 13,645 (47%) were confirmed to be Anopheles arabiensis, 9904 (34%) as An. funestus sensu stricto (s.s.), and 5193 (19%) as An. gambiae s.s. The combined average entomological inoculation rates (EIR) were 0.46 (95% CI 0.028–0.928) for An. gambiae s.s., 0.836 (95% CI 0.138–1.559) for An. arabiensis, and 0.58 (95% CI 0.165–0.971) for An. funestus s.s. with variations across different malaria transmission strata. Anopheles funestus s.s. and An. arabiensis were predominant in the Lake and South-Eastern zones, respectively, mostly in high malaria transmission areas. Monthly mosquito densities displayed seasonal patterns, with two peaks following the rainy seasons, varying slightly across species and district councils. Conclusion Anopheles arabiensis remains the predominant vector species followed by An. funestus s.s. in the country. Therefore, strengthening integrated vector management including larval source management is recommended to address outdoor transmission by An. arabiensis to interrupt transmission particularly where EIR is greater than the required elimination threshold of less than one (
Læs mere Tjek på PubMedMalaria Journal, 19.01.2024
Tilføjet 19.01.2024
Abstract Background Malaria remains a significant public health concern in Niger, with the number of cases increasing from 592,334 in 2000 to 3,138,696 in 2010. In response, a concerted campaign against the disease has been initiated. However, the implementation of these malaria interventions and their association with epidemiological behaviour remains unclear. Methods A time-series study was conducted in Niger from 2010 to 2019. Multiple data sources concerning malaria were integrated, encompassing national surveillance data, Statistic Yearbook, targeted malaria control interventions, and meteorological data. Incidence rate, mortality rate, and case fatality ratio (CFR) by different regions and age groups were analysed. Joinpoint regression models were used to estimate annual changes in malaria. The changes in coverage of malaria interventions were evaluated. Results Between 2010 to 2019, the incidence rate of malaria decreased from 249.43 to 187.00 cases per 1,000 population in Niger. Niamey had a high annual mean incidence rate and the lowest CFR, while Agadez was on the contrary. Joinpoint regression analysis revealed a declining trend in malaria incidence for all age groups except the 10–24 years group, and the mortality rate and the CFR initially decreased followed by an increase in all age groups. Niger has implemented a series of malaria interventions, with the major ones being scaled up to larger populations during the study period. Conclusions The scale-up of multi-interventions in Niger has significantly reduced malaria incidence, but the rise in mortality rate and CFR addresses the challenges in malaria control and elimination. Malaria endemic countries should enhance surveillance of malaria cases and drug resistance in Plasmodium, improve diagnosis and treatment, expand the population coverage of insecticide-treated bed nets and seasonal malaria chemoprevention, and strengthen the management of severe malaria cases.
Læs mere Tjek på PubMedMalaria Journal, 19.01.2024
Tilføjet 19.01.2024
Abstract Background Though Plasmodium vivax is the second most common malaria species to infect humans, it has not traditionally been considered a major human health concern in central Africa given the high prevalence of the human Duffy-negative phenotype that is believed to prevent infection. Increasing reports of asymptomatic and symptomatic infections in Duffy-negative individuals throughout Africa raise the possibility that P. vivax is evolving to evade host resistance, but there are few parasite samples with genomic data available from this part of the world. Methods Whole genome sequencing of one new P. vivax isolate from the Democratic Republic of the Congo (DRC) was performed and used in population genomics analyses to assess how this central African isolate fits into the global context of this species. Results Plasmodium vivax from DRC is similar to other African populations and is not closely related to the non-human primate parasite P. vivax-like. Evidence is found for a duplication of the gene PvDBP and a single copy of PvDBP2. Conclusion These results suggest an endemic P. vivax population is present in central Africa. Intentional sampling of P. vivax across Africa would further contextualize this sample within African P. vivax diversity and shed light on the mechanisms of infection in Duffy negative individuals. These results are limited by the uncertainty of how representative this single sample is of the larger population of P. vivax in central Africa.
Læs mere Tjek på PubMedJournal of Infectious Diseases, 19.01.2024
Tilføjet 19.01.2024
Malaria Journal, 18.01.2024
Tilføjet 18.01.2024
Abstract This paper examines the far-reaching implications of Triple Artemisinin-Based Combination Therapy (TACT) in the global battle against malaria. Artemisinin-Based Combination Therapy (ACT) is recognized for its cost-effectiveness, lower likelihood of adverse events, and widespread acceptance by patients and healthcare providers. However, TACT introduces novel dimensions to the fight against malaria that make them a superior choice in several aspects. TACT has been demonstrated to address resistance, offer a broader spectrum of action, reduce the risk of treatment failure, and can be tailored to meet regional needs, strengthening the global effort to combat malaria. However, maximizing these benefits of TACT depends on accessibility, particularly in resource-limited regions where malaria is most prevalent. Collaborative efforts among stakeholders, sustainable pricing strategies, efficient supply chains, and public–private partnerships are essential to ensure that TACT reaches needy populations. Moreover, dispelling prevalent malaria myths through health education campaigns is critical in this endeavour. The paper underscores the significance of collaborative initiatives and partnerships among governments, international organizations, research institutions, acadaemia, pharmaceutical companies, and local communities. Together, these efforts can pave the way for the acceptance, adoption, and success of TACT, ultimately advancing the global goal of a malaria-free world.
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