Malaria Journal最新文献

Background: Malaria is a critical global health issue, particularly for children in endemic regions. However, factors associated with recurrent severe malaria in children under 5 years of age in Northern Uganda are poorly understood. This study aimed to identify factors associated with readmission due to severe malaria within six months post-discharge among children in this age group.

Methods: A cross-sectional study was conducted in Otuke district, encompassing twelve health facilities. A total of 760 caregivers of children admitted with severe malaria were interviewed, and hospital records were reviewed to verify the readmission data. The primary outcome assessed was readmission with severe malaria within six months after initial discharge. Data analysis was performed via Stata version 15.0.

Results: The prevalence of readmission with severe malaria among children under 5 years of age was 26.8% (198/739). Factors significantly associated with readmission included having sickle cell anaemia [adjusted prevalence ratio (aPR) 1.72; 95% confidence interval (CI) (1.95-3.14)], living in houses constructed with straw and thatch walls [(aPR 2.10; 95% CI (1.19-3.69)] and seeking care after 12 h when the child has a fever [aPR 2.01; 95% CI (1.23-3.29)].

Conclusion: The findings indicate a high proportion of severe malaria readmissions in children under 5 years of age. Sickle cell anaemia, living in houses built using straw and thatch walls and seeking care after 12 h when a child has fever were the key risk factors for readmission with severe malaria. This study highlights the importance of targeted post-discharge interventions, such as prophylactic anti-malarials in addition to bed nets, to prevent recurrent infections especially among children with sickle cell disease. In addition, improvements in housing quality and timely treatment of children with malaria are essential for reducing the burden of malaria, particularly in endemic regions.

Background: The genetic diversity of malaria parasites varies between regions in the world. The genetic polymorphisms of the genes Pvs48/45 and Pvs47 which encode gametocyte/gamete proteins of Plasmodium vivax, were studied because of their potential as transmission-blocking vaccine (TBV) targets. The aim of the present study was to investigate the genetic diversity of Pvs48/45 and Pvs47 in clinical isolates from endemic areas of Thailand.

Methods: Plasmodium vivax samples collected from four provinces neighbouring either Myanmar or Malaysia were analysed using polymerase chain reaction and nucleotide sequencing.   RESULTS: Fifteen and 18 amino acid substitutions were observed in 36 Pvs48/45 and 62 Pvs47 deduced amino acid sequences, respectively. Eleven haplotypes were identified in Pvs48/45 and 26 in Pvs47. Overall, low nucleotide diversities were observed for Pvs48/45 (π = 0.00104) and Pvs47 (π = 0.00321). Tajima's D, and Fu and Li's D* and F* values were negative for both genes, Pvs48/45 and Pvs47 while a significant difference was found in Pvs48/45 (P < 0.05).

Conclusion: The limited polymorphism of the two investigated TBV candidate antigens observed in this study is consistent with findings in worldwide isolates. The collected genetic diversity data could be helpful for developing effective TBVs in malaria-endemic areas.

Background: In the context of high malaria burden yet limited resources, Guinea's national malaria programme adopted an innovative subnational tailoring (SNT) approach, including engagement of stakeholders, data review, and data analytics, to update their malaria operational plan for 2024-2026 and identify the most appropriate interventions for each district considering the resources available.

Methods: Guinea's malaria programme triggered the SNT exercise with a list of decisions that could be informed with local data. The programme established an SNT team, which determined intervention targeting criteria; identified, assembled, and reviewed relevant data sources; stratified malaria risk and its determinants to inform geographical targeting for each intervention; and used mathematical modelling to predict the impact of different intervention mix scenarios. The SNT analysis was performed at the district level, excluding the urban area of Conakry.

Results: Malaria incidence, malaria prevalence, and all-cause under-5 mortality were used for the epidemiological stratification of Guinea. Additional indicators relevant for decision-making including seasonality patterns, insecticide resistance, historical malaria interventions and vaccine coverage were also stratified. Stratified layers were used to inform the targeting criteria for each intervention to identify districts to prioritize for indoor residual spray, dual-action insecticide-treated nets, seasonal malaria chemoprevention (SMC), including number of cycles for each eligible district, malaria vaccine, and perennial malaria chemoprevention. Results of the SNT analysis were used to mobilize funding from the Global Fund for scale-up of dual-action nets and expansion of SMC.

Conclusions: SNT allowed Guinea's national malaria programme to adapt their intervention strategy at the health district level, an unprecedented approach in the country. The use of local data to inform eligibility and prioritization allowed the programme to identify the optimal mix of interventions for each district and to successfully mobilize resources to support their plans.

Background: Thrombocytopenia is a common haematological abnormality in malaria patients that is associated with an increased risk of mortality. Given the endemic nature of malaria in Ethiopia, it is crucial to comprehend the prevalence of thrombocytopenia in this setting to enhance clinical care. Therefore, this study aimed to systematically review and synthesize the available evidence on the prevalence of thrombocytopenia among malaria patients in Ethiopia.

Methods: This systematic review and meta-analysis reviewed studies on thrombocytopenia prevalence in malaria patients, using databases including PubMed, Google Scholar, EMBASE, African Journals online database, and Hinary. STATA version 17 software was used for statistical analysis. A random-effects model was used to estimate pooled effect sizes. Heterogeneity among the included studies was assessed using Galbraith, Cochran's Q test, and I² statistics. Subgroup analysis, sensitivity analysis, and meta-regression were conducted to identify the source of heterogeneity. Publication bias was evaluated using a funnel plot and Egger's test.

Results: Of the 154 studies identified, 31 that fulfilled the eligibility criteria were included in the meta-analysis consisting of 1173 study participants and 823 thrombocytopenic cases. The pooled prevalence of thrombocytopenia was 70% (95% CI: 63, 77) with significant heterogeneity. Subgroup analysis showed the highest pooled prevalence of thrombocytopenia in the Southern Nations Nationalities and Peoples' region (78.34%) followed by the Amhara region (69.7%), whereas the lowest prevalence was observed in the Gambella Region (63.4%). The sample size was responsible for the observed heterogeneity among the studies, as indicated by the statistically significant result in the meta-regression analysis (p = 0.001).

Conclusion: Thrombocytopenia is a frequent abnormality finding among malaria patients in Ethiopia, affecting a substantial percentage of individuals. The high frequency found in this research emphasizes the significance of regular platelet monitoring in the treatment of malaria patients. Further studies are needed to investigate the clinical implications of thrombocytopenia in malaria patients.

Background: Cambodia strives to eliminate all species of human malaria by 2025, requiring that foci among forest-exposed populations in remote settings be addressed. This study explores malaria risks amongst forest-exposed groups in Mondulkiri and Kampong Speu Provinces, Cambodia as part of a multi-stage study on novel mosquito bite prevention tools (Project BITE).

Methods: A serial cross-sectional survey explored the demographics, housing structure openness, mosquito bite prevention habits, and protection from malaria amongst three target groups: forest goers who work in the forest, forest dwellers who live in the forest, and forest rangers who patrol forested regions. Malaria prevalence data was collected at three time points using rapid diagnostic tests (RDTs) for febrile individuals and qPCR for all participants. Infection locations and travel patterns of Plasmodium falciparum-infected individuals were analysed for clustering and the potential movement of infections.

Results: 2935 participants were enrolled between October 2022 and February 2023, consisting of 1093 (37%) forest goers and 1787 (61%) forest dwellers across both provinces, and 55 (5%) forest rangers in Mondulkiri province. Most worked outdoors as farmers, day labourers, and forest collectors, and reported going to the forest five to seven days a week. For housing, 29% and 39% of participants reported living in partially open primary and secondary structures, respectively. The main methods of mosquito bite protection used were insecticide-treated nets, wearing long sleeves, and burning mosquito coils, with limited protection during the daytime and outside at night. All febrile individuals had negative RDT test results. For qPCR, 24 P. falciparum infections (< 1%) were detected among forest goers and dwellers, clustered in Pu Trom and Pu Nhav villages in Mondulkiri Province, and Banteay Roka and Banteay Roka Kirisenchey (M) villages in Kampong Speu Province. Plasmodium vivax cases were detected (216 cases, 5%) across all enrolled villages. Only two infections were found in forest rangers.

Conclusion: Malaria elimination strategies for forest-exposed populations in Cambodia should focus on vector intervention strategies that offer protection during the day and outside at night, and drug-based strategies to clear subpatent infections, targeting forest goers and dwellers in villages where cases are detected.

Background: Malaria occurred endemically in Germany until the twentieth century. Climate change and globalization are known to promote the spreading of malaria. Erlangen is a city with just under 120,000 inhabitants located in the Nürnberg metropolitan region, Federal State of Bavaria, Southern Germany. Historical findings, current climate data, microbiological data (local and state level) and vector surveillance data are used to estimate the risk of re-emergence and autochthonous transmission of malaria in the area of Erlangen.

Methods: Historical data was obtained by searching literature. Climatic data were retrieved from the German Climate Data Centre. Data on reported (supra-)regional infections were obtained from the Robert-Koch Institute. Cases of malaria diagnosed at the Institute of Clinical Microbiology, Immunology and Hygiene (University Hospital Erlangen) complement this data. The citizen science project "Mückenatlas" (Mosquito Atlas), the German mosquito database (CULBASE) and the company Biogents AG provided mosquito surveillance data.

Results: Malaria was highly endemic in Erlangen in the nineteenth century, with 18% of hospitalized patients suffering from this disease in 1860, but disappeared during the first half of the twentieth century. After the end of World War II, autochthonous 'malaria tertiana' (tertian malaria) occurred in neighbouring Nürnberg, demonstrating the regional malaria potential. In recent decades, the average monthly temperature increased by 1.6 °C. In Erlangen and the surrounding area, three potential vectors of tertian malaria parasites are prevalent (Anopheles messeae, Anopheles maculipennis sensu stricto, and Anopheles plumbeus). In addition, Anopheles daciae, which has unknown potential of Plasmodium transmission, and Anopheles claviger sensu lato have been detected. In recent years, malaria diagnosed in Erlangen mainly resulted from travelling to Africa. Plasmodium vivax accounted for only a small proportion of these cases (2010-2023: n = 5, 17%).

Conclusion: Future autochthonous transmission of malaria parasites in Erlangen is possible, although re-establishment of a natural transmission cycle is currently unlikely. In order to avoid unexpected autochthonous malaria, surveillance and prevention measures should be considered. Patients with fever after visiting endemic areas need to be analysed for Plasmodium infection.

Background: The study focused on the full population of children from Nigeria, where the dataset was obtained from the demographic and health surveys (DHS). About 10245 children were selected for the current study and based on the rapid diagnostic test (RDT) results, there is about 37% prevalence of malaria in children under 5 years old in Nigeria. Malaria is the leading public health concern, that contributes to child mortality in the African region.

Methods: The Nigeria Malaria Indicator Survey (NMIS) 2021 was utilized in this investigation. For the 2021 NMIS, a two-stage sampling technique was used. According to the NIMS study, the children chosen for anaemia and RDT testing were under 5 years of age.

Results: A generalized linear mixed model (GLMM) was used to examine malaria RDT findings in conjunction with demographic, geographic, and socioeconomic characteristics. The following underlying risk factors for malaria in children were discovered in the study: altitude, anaemia level, age in months, fever status in the past 2 weeks, toilet facility, main wall material, main roof material, household wealth index, type of place of residence, sex of the child, mother's education level, and knowledge of the preventative measures that can be used to prevent malaria.

Conclusion: Missing data were not deleted in this investigation; instead, multiple imputations utilizing chained equations were used to approximate the missing observation. Based on the results found by using the GLMM, the findings of this study may influence how the government combats malaria in Nigeria. The novelty of this study is that the missing values were not dropped. However, imputation techniques were explored, and multiple imputation by chained equations was used.

Background: The declining effectiveness of Intermittent Preventive Treatment in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) due to the emergence of Plasmodium falciparum resistance highlights the need for alternative malaria prevention strategies in pregnant women. A novel approach was proposed: screening with an ultra-sensitive rapid diagnostic test and treating positive with pyronaridine-artesunate (ISTp-uRDT-PA). This trial compared the impact of both strategies on maternal malaria and anaemia, abortion, intrauterine death, birth weight, preterm delivery.

Methods: This non-inferiority trial, conducted in Kinshasa, enrolled pregnant women in their second and third trimesters. Participants in the IPTp-SP arm (n = 124) received SP at monthly antenatal visit as per guidelines, while those in the ISTp-uRDT-PA arm (n = 126) were screened monthly with an uRDT and treated with PA if positive. Primary outcomes included asymptomatic parasitaemia (uRDT positive without fever) or symptomatic parasitaemia (uRDT positive with fever or history of fever, and parasite density by microscopy during pregnancy.

Results: Asymptomatic parasitaemia by uRDT during pregnancy was similar in both arms (20.8% in IPTp-SP vs 21.0% in ISTp-uRDT-PA). At delivery, asymptomatic parasitaemia was 51% higher in ISTp-uRDT-PA arm compared to IPTp-SP (cRR = 1.51 [95% CI 0.76-3.00], p = 0.24). Symptomatic parasitaemia by uRDT at delivery showed no significant difference. Malaria by microscopy at enrolment was detected in 34.4% of women. Malaria by microscopy during pregnancy was 9.6% in IPTp-SP and 10.1%. ISTp-uRDT-PA (p = 0.19), decreasing to 3.2% and 0.9%, respectively, at delivery (p = 0.24). Mean haemoglobin concentration at enrolment was 10.1 g/dl in the IPTp-SP and 9.8 g/dl in the ISTp-uRDT-PA with no significant difference in maternal anaemia at delivery (7%; cRR = 1.07 [95% CI 0.87-1.31], p = 0.52). No significant differences were found for spontaneous abortions and in utero death in both arms. The risk of a premature newborn declined by 14% in ISTp-uRDT-PA compared to the IPTp-SP arm (cRR = 0.86 [95% CI 0.29-2.85], p = 0.79) while low-birth-weight was not significantly higher (cRR = 1.74 [95% CI 0.86-3.53], p = 0.12).

Conclusion: ISTp-uRDT-PA was non inferior to IPTp-SP and can be considered as a future alternative for IPTp-SP in case this intervention can no longer be used due to high SP resistance.

Clinical trials registration: NCT04783051.

Background: Seasonal malaria chemoprevention (SMC) is a highly effective intervention for malaria prevention in high burden areas with seasonal transmission, historically implemented in the Sahel. Mozambique contributes to 4% of global malaria cases. Malaria Consortium, in partnership with the National Malaria Control Programme, conducted a two-year phased SMC study in Nampula province using sulfadoxine-pyrimethamine (SP) plus amodiaquine (AQ), or SPAQ, in children under five. Phase one results presented here highlight acceptability, feasibility, and protective effect of SMC.

Methods: A pragmatic type II hybrid effectiveness-implementation study design was adopted, using mixed methods. The study was conducted in three districts, utilizing: (1) non-randomized controlled trial reporting on malaria incidence; (2) drug resistance molecular marker study reporting on resistance marker changes over time; (3) coverage and quality assessment on the SMC distribution; and (4) a qualitative acceptability and feasibility assessment with stakeholders.

Results: Children who received SMC had 86% (hazard ratio 0.14, 95% CI 0.09-0.24) lower hazards of developing clinical malaria during the peak transmission season compared with children in the comparison district. Prevalence of SP molecular markers associated with resistance was high at baseline (K540E 66.1%). SMC achieved high coverage of eligible children over four cycles (87.7%, 95% CI 83.9-90.8%). Qualitative results indicate SMC was positively accepted by the targeted community.

Conclusions: Results suggest that SMC was effective at preventing clinical malaria, did not significantly impact resistance profile, and was feasible and acceptable in the context. Phase two will assess SMC impact in reducing malaria incidence and if chemoprevention efficacy of SPAQ is impacted by drug resistance and drug concentrations.

Background: Malaria transmission depends on the presence of gametocytes in the peripheral blood of infected human hosts. Understanding malaria infectious reservoirs enables transmission-blocking interventions to target the most important hosts for the disease. This study characterized the distribution of gametocyte carriage as a baseline for the clinical evaluation of a Pfs25-based transmission-blocking vaccine candidate in Bagamoyo, Tanzania.

Methods: A malaria survey was conducted in five locations from May to August 2022. A total of 467 participants-192 children (5-12 years), 65 adolescents (13-17 years) and 210 adults (18-45 years)-were enrolled. Malaria was detected using three methods: rapid diagnostic tests, light microscopy and quantitative polymerase chain reaction. The geometric mean of the gametocyte density, and weighted arithmetic mean of the gametocytes sex ratio were estimated.

Results: Overall, 23.5% (110/467) of the participants tested positive for malaria parasites, with the majority of positives (> 92%) being Plasmodium falciparum. The overall gametocytaemia was 5.6%, with a percent positivity of 6.8% (13/192), 6.2% (4/65) and 4.3% (9/210), in children, adolescents, and adults, respectively. The geometric mean gametocyte density (gametocytes/μL) was greater in adults (124.6) than in children (71.7) and adolescents (50.5). Regression analysis revealed that gametocytes were more likely to be present among male participants than among female participants [ORa: 2.79 (95% CI: 1.19 - 6.59) p = 0.019]. The gametocyte sex ratio in children and adult gametocyte carriers was similar but greater than that in adolescents.

Conclusion: The observed gametocyte densities and distribution across age groups suggest the need for malaria transmission-blocking interventions to target all populations in heterogeneous transmission settings. The implication of targeting only children may leave residual malaria transmission and reinfection from the left-out groups.