Malaria Journal最新文献

Background: Zoonotic (monkey) malaria, caused by Plasmodium knowlesi, is an escalating concern in Sabah, Malaysia, where humans, macaques and mosquito vectors share overlapping ecosystems. Conventional research methods often overlook how affected communities perceive and respond to this risk within their cultural and environmental contexts. This study uses photovoice, a participatory visual method to explore the question 'What does monkey malaria mean to you? and to elevate community voices in guiding locally relevant disease prevention strategies.

Methods: From January to May 2024, twenty participants aged 18 to 62 from three rural Sabah villages captured photographs over a 20-day period using their smartphones to document their experiences and perceptions on monkey malaria. Follow-up focus group discussions (FGDs) enabled participants to collectively reflect on and interpret their images. Reflexive thematic analysis was applied to the visual and verbal data and findings. Digital tools supported coordination and data management without replacing the participant-researcher engagement.

Results: Five interrelated themes were generated: (1) monkey malaria as an embedded, everyday risk, (2) community resilience manifested through locally derived practices, (3) structural and socio-ecological challenges shaping exposure, (4) the interface of human, wildlife, and environmental health, (5) cultural knowledge and blended practices for coping with malaria risk. Participants articulated how landscape features, economic dependence on forested and plantation areas, and daily routines collectively structure risk, reflecting a dynamic 'landscape of risk'. They also expressed aspirations for collaborative and culturally appropriate strategies.

Conclusion: Using photovoice, participants described how malaria risk is part of their everyday lives, the coping strategies they use and the social and environmental conditions that influence their understanding. By prioritising community voices, the findings show that effective malaria control should go beyond strictly biomedical models to include local priorities, cultural practices and lived experience. Photovoice generated deep insights grounded in the community context and encouraged meaningful participation, providing useful guidance for designing intervention strategies that are culturally appropriate and more sustainable.

Background: Insecticide resistance among malaria vectors remains a critical obstacle to effective vector control and malaria elimination across sub-Saharan Africa. This study assessed the phenotypic and genotypic resistance profiles of Anopheles coluzzii populations in three urban centres of Anambra State, Southeastern Nigeria: Awka, Onitsha and Nnewi.

Methods: Larvae were collected from Awka, Onitsha and Nnewi and reared to adults for WHO insecticide susceptibility tests. Species identification, molecular form determination (PCR-RFLP using HhaI enzyme) and screening for kdr L1014F and ace-1 G119S mutations were performed.

Results: Molecular diagnostics confirmed that all specimens were An. coluzzii. Mortality to deltamethrin was low across all sites (Awka: 63%, Onitsha: 61% and Nnewi: 45%), indicating resistance. DDT also showed markedly reduced susceptibility (Awka: 56%, Onitsha: 25% and Nnewi: 20%), consistent with resistance. In contrast, full susceptibility was observed to bendiocarb (100%) and pirimiphos-methyl (100%) in all locations. The kdr 1014F allele occurred at high frequencies across all locations (Awka: 0.72, Onitsha: 0.77 and Nnewi: 0.81), predominantly represented by RR and RS genotypes. In contrast, the ace-1 G119S allele was present at very low frequencies (Awka: 0.07, Onitsha: 0.10 and Nnewi: 0.12), with most mosquitoes carrying the susceptible SS genotype.

Conclusions: Urban An. coluzzii populations in southeastern Nigeria exhibit operationally significant resistance to pyrethroids and DDT, driven largely by high kdr allele frequencies, while remaining susceptible to carbamates and organophosphates. These patterns highlight the need for continued resistance surveillance and tailored insecticide-based interventions.

Background: This study aimed to assess the community-based prevalence of malaria reservoirs following cases visiting health facilities. The diagnostic performance of microscopy in detecting community-based malaria parasites was compared to nested polymerase chain reactions (PCR).

Methods: From July to October 2022, reactive case detection was conducted in Sile village, Gamo Zone, in the Southern Rift Valley of Ethiopia. Within six days of identifying an index case, all individuals in the same household and neighboring households were screened for malaria by microscopy, with nested PCR for confirmation. Asexual parasite and gametocyte density were measured microscopically.

Results: Of the 2434 individuals visited following 142 PCR-confirmed index cases, 2009 were included in the final analysis. The PCR-corrected, microscopy-based malaria prevalence in the study community was 3.6% (72/2009; 95% CI 2.8-4.5). Subsequent PCR analysis of randomly selected microscopy-negative samples identified an additional 33 submicroscopic infections, yielding a submicroscopic prevalence of 10.1% (33/326; 95% CI 7.2-13.9). Submicroscopic prevalence was 4.6% for P. vivax (15/326; 95% CI 2.6-7.5) and 4.3% (14/326; 95% CI 2.4-6.9) for P. falciparum. Mixed infections comprised 1.3% (4/326; 95% CI 0.3-3.1) of the cases. Overall, submicroscopic infections accounted for 31% (33/105; 95% CI 22.6-40.8) of the total PCR-confirmed malaria cases in the community, indicating that nearly one-third were missed by microscopic examination. Index cases had higher asexual parasite density (16,177 vs. 1900/μL; P < 0.001) but lower gametocyte carriage than reactive cases, despite similar gametocyte densities (600 vs. 482/μL; P = 0.08). The gametocyte carriage rate was higher among P. vivax (22/32; 69%) than among P. falciparum (6/27; 22%) reactive cases.

Conclusion: The high gametocyte carriage rate among microscopy-reactive cases highlights the potential role of community-based infections in sustaining malaria transmission.

Vector-borne diseases such as malaria are a threat to global public health and the economy. These diseases were proposed to be managed and controlled by new preventive strategies such as paratransgenesis. This is an innovative technique that makes use of symbiotic microorganisms to influence vector or targeted pathogens. The performed studies on Anopheles stephensi and Anopheles gambiae demonstrated that the carboxypeptidase-B1 enzyme plays a vital role in the sexual development of the Plasmodium parasite in the mosquito midgut by its enzymatic activity. Therefore, inhibiting its enzymatic activity could be a target for preventing approaches. Potato Carboxypeptidase Inhibitor (PCI) has desirable characteristics that make it a promising effector molecule for paratransgenesis. In this study, the inhibitory effect of PCI on Carboxypeptidase-1 from An. stephensi (CPBAs1) was evaluated. The coding sequence of the cpbas1 and pci genes were cloned into the pET-23a expression vector, expressed, and purified. Finally, the inhibitory effect of the PCI on CPBAs1 was evaluated in parallel with the 1,10-phenanthroline as the commercial-specific inhibitor. Our findings revealed that PCI could inhibit the enzymatic activity of the CPBAs1 efficiently in low concentrations. Given PCI's remarkable inhibition activity against the CPBAs1 and its suitable structural features, PCI could be considered as a potential effector molecule for use in the paratransgenesis approach in future related studies.

Introduction: Malaria remains a significant public health challenge, particularly in high-burden settings such as Uganda. Social and Behaviour Change Communication (SBCC) interventions play a vital role in influencing knowledge, attitudes, and practices related to malaria prevention. However, despite the widespread promotion of mosquito bed net (MBN) use, there is limited evidence on the comparative effectiveness of different media platforms in encouraging their adoption. This study estimated the effect of exposure to malaria messages from different media platforms on MBN use among women of reproductive age in Uganda using propensity score-matched analysis.

Methods: We conducted a secondary analysis of nationally representative data from the 2018-2019 Uganda Malaria Indicator Survey (UMIS), restricted to 3488 women aged 15-49 years who reported exposure to at least one malaria message. The primary outcome was MBN use, and the key exposures were nine distinct SBCC platforms. One-to-one nearest neighbour propensity score matching was applied, adjusting for key socio-demographic characteristics including age, education level, household wealth index, place of residence, and region. Propensity score matching analysis (PSMA) was applied to estimate the average treatment effect on the treated (ATT) for each platform, with ATT chosen to quantify effects among women who were actually exposed to malaria-related messages, adjusting for relevant observed covariates. Data analysis was done in Stata V14.0.

Results: Of the 3488 women included in the study, 73.2% reported using MBN the previous night before the survey. Propensity score matched analysis revealed that exposure to malaria messages through community health workers (ATT = 0.322, 95% CI 0.111, 0.533), community events (ATT = 0.296, 95% CI 0.085, 0.507), and social mobilization (ATT = 0.185, 95% CI 0.008, 0.362) significantly increased MBN use. Other effective channels included social media, radio, interpersonal communication, and billboards. Television exposure (ATT = 0.051; 95% CI  - 0.062, 0.164) and exposure from other unspecified sources were not significantly associated with MBN use.

Conclusion: Among women exposed to malaria messages, exposure through community health workers and community events showed the strongest associations MBN use, followed by exposure through social mobilisation and other SBCC platforms. Exposure through television was not significantly associated with MBN use, suggesting that community-based and interpersonal communication channels may be more strongly associated with MBN utilisation than some mass media platforms.

Background: Malaria remains a significant public health challenge, particularly in the Khyber Pakhtunkhwa (KP) province, where transmission patterns vary across districts. This study aimed to identify the determinants of malaria transmission using model selection techniques.

Methods: A cross-sectional study was conducted among general population across various districts in KP, including northern, central, and southern zones. A total of 768 participants across the province were surveyed using a structured questionnaire having socio-demographic variables, housing conditions, access to healthcare, and preventive practices. Malaria infection was diagnosed using the combo rapid diagnostic test. Logistic regression models, including automated model selection techniques, were employed to identify significant predictors of malaria.

Results: The overall proportion of malaria among respondents was 24.5%. Bivariate analysis showed that male gender, younger age (16-30 years), joint family system, low education, poor housing conditions, low income, long distance to health centers, and non-use of bed nets were significantly associated with malaria (p < 0.05). Final multivariate model results identified gender (AOR 1.8, CI 1.1-2.8, P < 0.05), age group 16-30 years (AOR 4.2, CI 2.1-8.5, P < 0.01), age group 31-50 years (AOR 8.3, CI 4.2-16.3, P < 0.01), age group > 50 years (AOR 3.6, CI 1.9-6.7, P < 0.01), family type (AOR 2.6, CI 1.47-4.61, P = 0.001), education level (AOR 3.9, CI 2.6-5.9, P < 0.01), income level (10,000-50000 rupees) (AOR 17.8, CI 8.1-38.9, P < 0.05), large family size (AOR 11.3, CI 5.9-21.7, P < 0.05), distance of > 3 km to healthcare facilities (AOR 3.1, CI 1.8-5.3, P < 0.01), and lack of modern toilets (AOR 4.8, CI 2.4-9.4, P < 0.01) as independent risk factors of malaria prevalence.

Conclusion: The study highlights multiple risk factors contributing to malaria prevalence in KP. Tailored interventions, including improved access to education, healthcare, sanitation, and preventive tools like bed nets, are critical. Future studies incorporating geographic mapping and seasonal trends are recommended to strengthen targeted malaria control strategies.

Background: The R21 malaria vaccine has recently been rolled out in Uganda and other endemic settings across sub-Saharan Africa. Its implementation, faces many potential challenges. We assessed caregivers' awareness, knowledge, attitude, and perceptions towards the vaccine in northern Uganda.

Methods: A sequential explanatory mixed methods study was conducted in Kole and Kwania districts, Northern Uganda. Quantitative data were collected through a structured survey of 574 randomly selected caregivers of age-eligible children. Qualitative data were gathered through follow-up focus group discussions with caregivers. Descriptive statistics and exploratory factor analysis were used to assess knowledge and latent dimensions of attitudes and perceptions. Qualitative data were transcribed verbatim, anonymized, organized within ATLAS.ti version 25, and analysed using deductive thematic analysis.

Results: Among the 574 caregivers 90.1%, (95% CI 87.3-92.4) were aware of malaria vaccine. However, only 13.9% (95% CI 11.2-17.0) demonstrated factual knowledge regarding key aspects of malaria vaccine including; number of doses required (16.4%), dosing intervals (21.0%), and age eligibility (34.2%). Overall, 57.4% of the caregivers expressed positive attitudes and 57.5% reported positive perceptions towards the vaccine. Common factor analysis (CFA) revealed two key dimensions of vaccine attitudes: caregiver confidence (54.9%) and safety concerns (49.7%). Regarding perceptions, three factors emerged: vaccine confidence (56.5%), trust in delivery (54.9%), and safety concerns. While most caregivers stated confidence and trust, nearly half reported lingering concerns. Qualitative data reinforced these results and revealed five central themes: caregivers' knowledge and awareness of the malaria vaccine; enduring community misconceptions; mixed attitudes reflecting trust, and fear; and perceptions related to vaccine's safety, effectiveness, and value for child-health.

Conclusion: Although, factual knowledge was limited, caregivers reported high awareness of malaria vaccine, alongside positive attitudes and perceptions tempered by safety concerns. The Ministry of Health needs to implement regular, nationwide community education campaigns anchored in locally tailored communication strategies.

Background: Despite significant progress in malaria control, malaria remains a major public health issue in Ethiopia. Regular trend analysis is essential for assessing the effectiveness of interventions.

Methods: A retrospective study was conducted from 2020 to 2024 at Mattu Karl Comprehensive Specialized Hospital. Laboratory records of patients tested for malaria were reviewed to assess annual trends and Plasmodium species distribution.

Results: Out of 100,760 patients tested by microscope over the five years, 14,303 (14.2%) were positive for malaria. Plasmodium vivax accounted for 49.1% of cases, Plasmodium falciparum; for 37.8%, and mixed infections for 13.1%. Females represented 51.4% 0f the suspected patients and 51.8% of the confirmed cases. The positivity rate rose from 9.2% in 2020 to 17.7% in 2024.

Conclusion: Malaria incidence increased over the study period with a concerning rise in mixed infections. The results underscore the need for enhanced malaria control strategies tailored to species dynamics.

Introduction: Malaria remains a major public health issue in Southeast Asia, with Plasmodium knowlesi (P. knowlesi) emerging as a growing threat. Despite intensified prevention and control efforts, populations in this region remain highly vulnerable to this zoonotic disease, driven by the complex interactions between primates, mosquitoes, and humans. This study aims to explore understanding of the factors affecting communities vulnerable to P. knowlesi malaria and their preventive behaviours, tailored to the local context.

Methodology: A group of participants with substantial expertise and experience in malaria programme implementation and field operations were assembled. Utilizing the Nominal Group Technique (NGT), a validated and systematic approach for facilitating group discussions aimed at consensus, we identified the essential points to prioritize factors affecting at-risk communities and their malaria prevention behaviours. NGT were conducted through virtual platforms in October 2024, achieving consensus when 80% of the experts concurred on specific ideas. Final rankings were established based on descending acceptance percentages.

Result: Of the 21 items presented for voting, 20 were retained for final ranking, demonstrating a strong panel consensus on key factors influencing malaria risk and prevention behaviours. The voting response rate was 100%, and consensus was achieved in a single NGT round. The 20 selected items, endorsed by the expert panel, were categorized into four overarching themes: environmental risks, human-related risks, policy and organizational factors, and vector-related risks.

Conclusion: These findings provide a valuable foundation for refining malaria prevention strategies. Future research can leverage this consensus to deepen the understanding of malaria-prevention behaviours and enhance P. knowlesi malaria programs tailored to at-risk communities.

Background: Despite substantial investments in malaria control, the disease remains a major burden in sub-Saharan Africa, particularly Uganda. Novel tools such as gene drive systems are being developed to suppress malaria vector populations, but their deployment requires detailed knowledge of mosquito population genetics.

Methods: The genetic structure, diversity, and demographic history of Anopheles gambiae and Anopheles arabiensis were assessed at six sites in Uganda: three islands in Lake Victoria and three mainland sites. A total of 2918 An, gambiae and 173 An. arabiensis were genotyped using targeted amplicon sequencing of 62 loci across coding and non-coding regions of the genome.

Results: Population structure analyses revealed clear separation between the two species but little differentiation within each species across sites. Pairwise F_ST values among An. gambiae populations were low (0.00054-0.028) but often statistically significant, with mainland populations showing higher connectivity and island populations exhibiting greater isolation. Anopheles arabiensis mainland populations showed no statistically significant differentiation, suggesting panmixia. Principal component analysis and Bayesian clustering similarly distinguished species-level structure but no obvious substructure within sites. Mainland An. gambiae populations displayed higher nucleotide diversity than island populations, while An. arabiensis showed the lowest diversity overall. Tajima's D values were negative across sites, consistent with recent population expansions. Effective population size estimates indicated small populations at the islands (146-249) compared to large mainland populations (4054-8190).

Discussion: These findings demonstrate strong genetic differentiation between An. gambiae and An. arabiensis, and subtle but meaningful structure between island and mainland An. gambiae populations. The reduced diversity and small effective population sizes at island sites suggest stronger genetic drift and limited gene flow, in contrast to the highly connected mainland populations.

Conclusion: This study highlights how geographic and ecological factors shape mosquito population structure and provides critical evidence for the design and monitoring of genetic-based vector control interventions, including the planning and evaluation of field trials.