Malaria Journal最新文献

Background: In-depth analysis of distributions of historical malaria outbreak years is crucial for evaluating progress in malaria control, understanding the impact of previous interventions, and identifying regions that remain highly susceptible to outbreaks.

Methods: Numerous methodologies, including the 95% CI method, the Cullen method, the quartile method, and the C-sum method, have been documented in the literature as potential approaches for calculating malaria outbreaks, each with its pros and cons. Data from the past decade was used to establish a robust criterion to define a malaria outbreak year, i.e., if the number of malaria cases in a specific year surpassed the value derived from the sum of the last three years' moving average and 2.5 times the last three years' moving standard deviation.

Results: Over the past decade, India has grappled with 402 outbreak years of malaria in various districts. Notably, the years 2011, 2014, and 2015 stand out due to their high frequency of case upticks, marking peak periods in the country's recent epidemiological history. Subsequently, there was a sharp decline in the number of district-wise outbreak years after 2015, with 2020 recording the lowest number of outbreaks to date. Among 28 states, seven-Mizoram, Tripura, Jharkhand, Odisha, Madhya Pradesh, Uttar Pradesh, and Meghalaya-have been identified as "more outbreak-prone states" because over 70% of their districts experienced at least one outbreak year between 2011 and 2020.

Conclusions: The frequency of outbreak years in India has decreased over the last decade. Districts susceptible to case upticks require specific, heightened, new modes of surveillance and targeted interventions to address future occurrences of malaria outbreaks in India.

Background: Despite ongoing reports of malaria from health facilities in central Ethiopia, entomological evidence on local vectors remains scarce. This study investigated Anopheles species composition, host preferences, and entomological inoculation rates in this urban setting.

Methods: A repeated cross-sectional and longitudinal entomological study was conducted in six districts (woredas), each of which had access to one of the three health centers (Akaki, Gelan, and Serti). Adult mosquitoes were collected from the houses of individuals with microscopically confirmed malaria, who served as the index cases, as well as from nearby animal shelters using CDC-LT and PKA. DNA of anophelines was used for species identification, blood meal source analysis, and detection of P. falciparum and P. vivax infections.

Results: Of 302 Anopheles collected, seven species were identified, including An. christyi (50.0%), An. arabiensis (21.5%), An. amharicus (7.6%), An. cinereus (5.0%), An. garnhami (1.3%), An. stephensi (1.3%), and An. rhodesiensis (0.7%). Two of these species, An. amharicus and An. stephensi, were recorded for the first time in the area. Analysis of abdominal contents of the 192 blood-fed females revealed that bovine blood was the most common (87.0%), followed by goat (34.9%) and human blood (25.5%). All four vector species (An. arabiensis, An. amharicus, An. stephensi, An. christyi) showed strong zoophilic (mostly feeding on cattle), though human blood and mixed human-bovine feeds were also detected in each of these species. P. falciparum sporozoites were detected in An. arabiensis, confirming its role in local transmission.

Conclusion: Seven Anopheles species were identified, of which Anopheles christyi was the most abundant species, followed by An. arabiensis. The presence of An. amharicus and invasive An. stephensi, combined with zoophilic yet opportunistic feeding behavior and P. falciparum-infected An. arabiensis, highlights local variations in the importance of these vectors and ongoing endemic transmission in this urban Ethiopian setting.

Introduction: The shift to universal insecticide-treated nets (ITN) coverage in Malawi creates opportunities for establishing effective social and behavior change (SBC) interventions which target general populations, including couples. However, couple concordance in ITN use has not been well analyzed. We explored couple dynamics and concordance related to ITN use in Malawi to inform the potential role of couple-centered SBC approaches to improve consistent ITN use.

Methods: The analysis focuses on 1213 male-female couples or dyads, a subset of a nationally representative survey. Key variables for both members of the couple included consistent net use and ITN Ideation, the combination of cognitive, social, and emotional factors related to a behavior measured as a composite score of several psychosocial factors. We assessed concordance (level of agreement) between men and women in the couple using Cohen's Kappa statistic (K). Crude and adjusted logistic regressions identified factors associated with couples' concordance in ITN ideation and consistent net use, adjusting for household and couple characteristics.

Results: Over one-half (54%) of couple dyads reported consistent ITN use among both partners (k = 0.81). Factors significantly associated with couples' concordance in high ITN ideation included residence in Central (adjusted odds ratio [aOR]: 2.27: 95% confidence interval [CI] 1.59-3.25) or Southern (aOR: 2.35; 95% CI 1.42-3.91) regions of Malawi compared to the North; wealthier households (aOR: 2.05; 95% CI 1.20-3.51); and having a primary education (aOR: 1.59; 95% CI 1.15-2.20). The most important couple-level factor associated with concordance in net use was concordance in ITN ideation (aOR: 1.66; 95% CI 1.08-2.55).

Discussion: Our study demonstrated couples are likely either to jointly use or not use ITNs consistently, suggesting a couples' approach may be worth exploring when designing and implementing SBC programs to promote consistent ITN use. This may necessitate addressing norms regarding couples' use of ITNs to encourage discussion of malaria prevention and ITN use among couples.

Background: Malaria continues to be the foremost deadly disease and a cause of substantial economic deficit in Ethiopia. Data from malaria monitoring programs can be used to assess prevalence and trends of the disease over time in a way to inform policy makers and prioritize control strategies. The current study assessed the malaria case trend between 2019 and 2024 based on data from 12 districts and two towns of Hadia, Gurage and Yem zones in Central Ethiopia Region.

Methods: A retrospective study design was employed to assess a six-year (2019-2024) trend of malaria cases in 12 districts and two towns selected purposively based on their location in the Ghibe valley and level of malaria burden with the support of local health authorities. District level aggregated malaria surveillance data was obtained from archives of the district and zonal health offices, carefully reviewed and analyzed. Descriptive statistics was used to calculate frequencies and percentages of seasonal and yearly malaria suspected as well as Plasmodium falciparum and Plasmodium vivax infected cases using Statistical Package for the Social Sciences version 25 software. Pearson Chi-square (χ2) was used for the test of statistical differences between/among variables. A post-hoc analysis of pairwise comparisons was carried out for identifying the specific significant difference among the groups.

Results: There were 86,604 (23.5%) Plasmodium positive individuals among the total 368,490 suspected in the previous six years period. Among the 86,604 Plasmodium positive cases, 61% were attributed to P. falciparum and 39% to P. vivax. The analysis showed increasing trend of the Plasmodium infected cases starting from 2019 with some fluctuations. The number of cases peaked in May (13,811;15.9%), autumn season (27,266; 31.5%) and spring season (25,555; 29.5% of Ethiopia. The distribution of P. falciparum and P. vivax cases differed significantly across the districts, months, seasons and years.

Conclusion: Plasmodium falciparum and P. vivax are endemic in Hadia, Gurage and Yem zones of Central Ethiopia Region. The number of cases has been increasing since 2019 in the region and highest in May, June, October and September. Furthermore, the cases peaked during the autumn and spring Ethiopian seasons, which coincide with the key farming and harvesting seasons. There is a need to sustain and scale up existing malaria intervention measures.

Background: Entomological outcomes are critical for understanding the biological mechanisms and operational performance of malaria vector control interventions. However, the quality and consistency of how these outcomes are measured and reported in cluster randomised controlled trials (cRCTs) is unclear. We conducted a systematic review of design features, sampling methods, and metrics used for measuring entomological outcomes in malaria vector control cRCTs. Our aims were to assess the consistency and quality of entomological study designs and examine how key design features influence the precision of reported entomological effect sizes.

Methods: Malaria cRCTs in the published literature were identified in four databases and two trial registries. We extracted information on entomological outcomes measured, entomological sampling strategies and trial design features. To evaluate overall design quality, we created an Entomological Study Design Risk (ESDR) metric that assessed trials across four domains related to power analysis and sampling design; with domain ratings combined to generate an overall ESDR score. We also used a linear mixed-effects model (LMM) to examine how the use of power analysis and the number of clusters and sampling points in entomological sampling influenced the precision of main entomological outcomes.

Results: Sixty-two cRCTs of malaria vector control interventions were identified between 1992 and 2021; with 74% being conducted in Africa. Thirteen different entomological outcomes and 12 sampling methods were used across trials: with considerable variation in the frequency of entomological sampling within trials. In total, 70% of the cRCTs were categorized as having high potential entomological design risk based on a combination of the lack of power analyses and inadequate or unclear randomisation of sampling points. The only significant predictor of the precision of entomological outcomes was the number of entomological clusters in which data were collected (greater precision as cluster number increased).

Conclusions: There is substantial variation in how entomological outcomes are measured and reported in cRCTs, and limited incorporation of key design features such as power analysis and random selection of sampling points for outcome measurement. Standardization where possible and clearer reporting guidelines for entomological components are therefore needed to improve the quality, comparability, and policy relevance for future trials.

Background: Anopheles pseudopunctipennis is the primary malaria vector in Mexico and is widely distributed nationwide. Understanding its developmental biology is crucial for interrupting malaria transmission.

Methods: This study was conducted in Tapachula, Chiapas, a city located in southeastern Mexico. Oviposition and fecundity patterns were determined in nulliparous and parous females, individually and in groups, under insectary and semi-field conditions.

Results: Regardless of whether they were grouped or individual, insectary-reared or field-collected, mosquito females exhibited a primary oviposition peak between 18:00 and 20:00, followed by a gradual decline until midnight. While nulliparous females from the insectary ceased oviposition after 24:00, a small percentage of parous females continued laying eggs throughout the night, until shortly before dawn (between 24:00 and 06:00). Parous females laid more eggs than nulliparous females CONCLUSION: Nulliparous and parous females of An. pseudopunctipennis exhibited a major oviposition peak between 18:00 and 20:00, a few minutes after sunset. Oviposition activity persisted, albeit at a lower rate, until 24:00. A small subset of parous females continued ovipositing until 6:00. Parous females were observed laying more eggs than nulliparous females. Based on the high activity of An. pseudopunctipennis, from dusk until midnight, chemical control with pyrethroid insecticides applied by ultra-low volume (ULV) or by thermal fogging is proposed in breeding sites during this period, in areas near localities with active malaria transmission.

Background: Malaria remains a major public health challenge in Benin, particularly among children under five years of age. Despite the wide deployment of vector control measures the disease burden remains high. Based on modeling approach, this study evaluates the potential impact and effectiveness of the introduction of the RTS, S/ASO1 malaria vaccine on the reduction of malaria-related morbidity in the province of Couffo.

Methods: An Epidemiological Multi-Diseases Model (EMOD) was parameterised using entomological, epidemiological, and climatic data from Benin covering the period 2010-2023. The RTS,S/AS01 vaccine was implemented via the Expanded Programme on Immunisation (EPI) strategy used to track children under five years old in 1000 populations. Nine scenarios were simulated, combining different coverage levels and dose schedules, alongside a baseline scenario without vaccination. One-way ANOVA and Tukey's HSD post hoc test were computed to assess differences between scenarios and to identify the best-performing scenario. Data processing, visualisation, and analysis were performed in R version 4.5.1 (2025-06-13 ucrt).

Results: The simulations revealed a substantial reduction in malaria burden associated with increasing vaccine coverage. Scenarios with higher coverage and booster doses achieved greater declines in both parasite prevalence, severe and clinical cases. Scenario 9, with 90% coverage and two boosters, resulted in the highest proportion, with 9.8% of PfPR averted, 11.06% of cases averted, and 21.83% of severe cases averted over 2030, demonstrating the synergistic effect of extended immunity through booster administration. Temporal analyses from 2024 to 2030 indicated a sustained decline in malaria incidence under the booster strategies, whereas limited gains were observed in scenarios with lower coverage.

Conclusion: These findings support policy efforts to integrate RTS,S/AS01 into Benin's Expanded Programme on Immunisation (EPI) and highlight the importance of continuous surveillance to monitor vaccine performance under real-world conditions.

Background: Placental malaria remains a significant contributor to adverse maternal and neonatal outcomes in malaria endemic settings globally. This study investigated the prevalence of placental malaria and associated factors among pregnant women delivering in Health facilities in Mayuge district, eastern Uganda.

Methods: A cross-sectional study was conducted in health facilities in Mayuge district. Blood samples were collected into EDTA tubes from the maternal side of the placenta. Thin and thick blood smears were prepared and stained with 10% Giemsa and screened for malaria parasites using microscopy. The blood samples were further screened for sub-microscopic Plasmodium falciparum parasites using quantitative polymerase chain reaction (qPCR). Interview data was collected using a questionnaire which collected data on sociodemographic factors, antenatal care (ANC) attendance, malaria prevention practices and use of antimalarial agents. The data was captured using an online platform and transferred into STATA version 17 for analysis. The analysis was done at 95% level of significance.

Results: A total of 180 participants were recruited into the study and had an average age of 23.2 ± 5.8. The proportion of participants with placental malaria by microscopy, qPCR was 11.67% (95% CI 7.71%-17.28%) and 23.89% (95% CI 18.19%-30.71%), respectively. Being between 15-to-19 years of age and those who did not attend any antenatal care during pregnancy were significantly associated with an increased odds of having placental malaria (aOR: 5.87, p = 0.023) and (aOR: 4.27, p = 0.011), respectively.

Conclusion: Placental malaria is common among pregnant women delivering in health facilities in eastern Uganda. Having less than three antenatal care visits is significantly associated with placental malaria among pregnant women. The Ministry of Health and development partners need to provide awareness to the population to help increase ANC attendance among pregnant women in communities.