Malaria Journal最新文献

Background: Effective interventions for controlling Anopheles malaria vectors depend on accurately identifying the species. Venezuela has the highest malaria prevalence in the region of the Americas; however, there is very limited knowledge about the vectors, especially regarding species complexes and their distribution.

Objectives: To conduct molecular taxonomy and phylogenetic analysis of the Albitarsis, Nuneztovari, and Oswaldoi complexes from malaria-endemic regions of Guyana and Venezuela using mtCOI sequences.

Methods: Anopheles were collected in Guyana (Potaro-Siparuni Region) and Venezuela (five municipalities). Species identification was carried out by analyzing mitochondrial cytochrome C oxidase (mtCOI) gene data using MrBayes, TCS, Posterior Probabilities of Correct Identification (P ID), Rosenberg's P (AB) values, and P (Randomly Distinct) as species delimitation approaches.

Findings: Four distinct taxa were identified: An. albitarsis F, An. goeldii, An. oswaldoi A and An. oswaldoi B. Anopheles oswaldoi A and An. oswaldoi B occurred sympatrically in Boca de Nichare, Bolívar State, Venezuela.

Conclusion: Anopheles goeldii is reported for the first time from Guyana and Venezuela, and discuss its role as vector of malaria parasites in both countries and its relative recent colonization. Anopheles oswaldoi A is reported for the first time from Venezuela. Anopheles albitarsis F, an important malaria vector in Colombia and Venezuela, is confirmed as the only species of the Albitarsis complex widely distributed in Venezuela. Our results will be valuable for future research aimed at clarifying the status of these significant species complexes in the region.

Background: In Senegal, the main vector control strategies include indoor residual spraying (IRS) and the distribution of insecticide-treated nets (ITNs). However, drugs and insecticides resistance have become a major challenge in the fight against malaria transmission. Addressing the problem of escalating resistance is vital to maintaining progress towards malaria elimination, which has stalled in recent years. New formulations belonging to the neonicotinoid class, clothianidin, have been developed and is now being used for malaria vector control through IRS.

Methods: The residual efficacy of clothianidin-treated walls was assessed monthly using WHO cone bioassays. Five houses in each of the two treated villages were evaluated, while one untreated house served as a control. In the experimental huts, a total of six huts, three in banco (mud) and three in cement, were evaluated on a monthly basis. Three cones were installed on three walls of each sprayed house at heights of 0.5 m, 1 m and 1.5 m above the ground, and three additional cones were placed in the control house. Ten female Anopheles coluzzii mosquitoes, aged between 3 and 5 days and derived from a laboratory-susceptible strain, were exposed in each cone for 30 min. After exposure, the mosquitoes were transferred to cups and mortality rates were recorded up to four days after exposure.

Results: Results demonstrate high efficacy of SumiShield 50WG on mud and cement substrates, residual activity for up to twelve months in experimental huts and eight months under field conditions. In experimental huts, the 96 h mortality rate of the susceptible mosquito strain remained at 100% throughout the study, except in months ten and twelve for mud-walled huts, and months six and ten for cement-walled huts, where mortality rates were 98.33%, 99.16%, 95.68%, and 97.52%, respectively. In the field sites of Bandafassi and Tomboronkoto, the 72 h mortality rate of the susceptible strain remained consistently at 100% over the eight-month period.

Conclusions: Clothianidin, a neonicotinoid insecticide, has not yet shown resistance in malaria vectors in Senegal. SumiShield 50WG is effective for resistance management through a rotation strategy using insecticides with different modes of action across spray cycles.

Background: The clinical and laboratory distinction between malaria and bacterial blood stream infections in patients with undifferentiated fever remains challenging. Misclassification may result in ineffective treatment with the risk of progression of disease and subsequent morbidity and mortality. A pragmatic solution is the use of multi-disease treatments effective against both malaria and the clinically most relevant bacterial pathogens. Fosmidomycin and clindamycin are two antibiotics that have demonstrated high efficacy in treating malaria. A multi-drug combination treatment of fosmidomycin, clindamycin, and artesunate has been evaluated for the treatment of malaria. To further explore whether fosmidomycin and clindamycin could be used in combined anti-malarial, anti-bacterial broad-spectrum chemotherapeutic treatment, the in vitro anti-bacterial activity of fosmidomycin and clindamycin was assessed against clinically relevant bacterial pathogens responsible for blood stream infections in sub-Saharan African children.

Methods: In vitro drug susceptibility testing was performed using clinical isolates of bacterial bloodstream infections from febrile, hospitalized children in Ghana. Isolates included the most common bacteria responsible for bloodstream infections in sub-Saharan African children, comprising Klebsiella pneumoniae, Escherichia coli, Streptococcus pneumoniae, Staphylococcus aureus, and non-typhoidal Salmonella (NTS). Minimum Inhibitory Concentrations of fosmidomycin and clindamycin were determined using the agar dilution method.

Results: The findings of in vitro antimicrobial susceptibility testing demonstrated that all tested strains showed susceptibility to at least one of the antibiotics tested. Gram-negative strains demonstrated susceptibility to fosmidomycin (100%) but resistance to clindamycin, while gram-positive strains showed the opposite pattern: susceptibility to clindamycin (100%) but resistance to fosmidomycin.

Conclusions: The results underscore the potential of combining fosmidomycin and clindamycin in antimalarial treatment regimens as a multi-disease treatment strategy, particularly for febrile children. Such an approach would target both Plasmodium falciparum and the clinically most relevant bacterial pathogens, addressing one of the most important diagnostic and treatment challenges faced in malaria-endemic regions.

Background: Like other countries in the WHO African Region, malaria remains a critical public health threat in Liberia, contributing to a significant proportion of outpatient visits, hospital admissions, and deaths, particularly among vulnerable populations such as children under five and pregnant women. Despite extensive control efforts, malaria continues to cause significant illness and death among young children and pregnant women in sub-Saharan Africa, including Liberia. This study aimed to investigate the socioeconomic, demographic, biological, geographic, and behavioural factors associated with malaria infection among children under five between coastal and inland counties of Liberia.

Methods: This study analysed secondary data from the 2022 Liberia Malaria Indicator Survey that is nationally representative and included a total weighted sample size of 2,189 children under 5 years (aged 6-59 months). Descriptive statistics was done using the guide to DHS Statistics (DHS-8). A two-proportion Z-test was also done to determine statistically significant difference in malaria prevalence between coastal and inland regions of Liberia. Logistic regression was used to identify the determinants impacting malaria in children under five.

Results: The study revealed malaria prevalence among under-five children was 8.3% in coastal and 12.7% in inland regions. It (Z = 3.33, p = 0.001) showed a significant difference between the two regions. Logistic regression identified key predictors: children not sleeping under ITNs had 1.5 times higher odds of malaria; all anaemia levels increased risk, with severe anaemia showing the highest odds (AOR = 6.2; 95% CI 2.34-14.81); children from poor households had the greatest risk (AOR = 6.4; 95% CI 3.06-13.27); infants (0-11 months) had lower odds (AOR = 0.04; 95% CI 0.01-0.17); and urban children were less likely to have malaria than rural ones (AOR = 0.6; 95% CI 0.40-0.86).

Conclusion: This study revealed that malaria infection among children under five varies substantially across Liberia, with inland and some coastal counties showing higher prevalence. Malaria risk was linked to anaemia, child age, ITN use, household wealth, and place of residence. Targeted interventions should prioritize inland counties and high-risk groups, particularly children under five from poor households, non-ITN users, anaemic children, and rural residents.

Background: In Kenya, limited clinical data on hospitalized malaria patients restricts insights into disease severity and care quality. Using data from the Integrated Facility-based Surveillance (IFBS) system-a sentinel surveillance platform for febrile illnesses across twelve facilities-the assessment focused on risk factors for severe illness and mortality, diagnostic accuracy of microscopy, and adherence to severe malaria treatment guidelines.

Methods: Analysis of IFBS data obtained from June 2017 to July 2024 was performed using bivariable logistic regression to identify factors linked to severe illness and deaths. Microscopy results were compared with PCR results to assess diagnostic concordance. Evaluation also included whether patients received parasitological confirmation before treatment and if severe cases received IV artesunate followed by artemether-lumefantrine (AL), per standard guidelines.

Results: Among 8,487 inpatients, 2,197 (25.9%) tested positive for malaria by either microscopy or rapid diagnostic test; among malaria cases, 713 (32.5%) had severe disease and 16 (0.7%) died. Infants had greater odds of severe illness compared to older ages (odds ratio [OR] was < 1.0 for other age groups compared to ≤ 1 year-old). Both severe illness and death were associated with fever duration of ≥ 5 days compared to ≤ 1 day (ORs: 3.67 and 8.00, respectively) and having been referred from another facility (ORs: 3.01 and 3.15, respectively). Positive microscopy at the health facility was PCR negative in 21% of patients. Only 15% of severe cases were documented to have received both IV artesunate and AL, while 17% received IV quinine.

Conclusions: Modifiable factors that suggested delayed care-seeking were associated with worse malaria outcomes in Kenya. Furthermore, gaps in diagnostic accuracy and adherence to treatment protocols for severe malaria were observed during chart review. These findings point to the importance of behaviour change strategies as well as messaging in the community that promote timely care-seeking, referrals and follow-up, especially for the youngest children. Potential malaria over-diagnosis underscores the need for strengthening quality assured microscopy programs with adequate training of microscopists and properly functioning microscopes and reagents, as well as an external quality assurance programme that routinely provide feedback on performance and identify areas for improvement.

Background: Malaria remains a significant public health challenge in Madagascar, affecting vulnerable populations including children under five and pregnant women. Despite global progress in reducing malaria cases and deaths, Madagascar continues to experience a high burden due to inequities in access to prevention, diagnosis, and treatment.

Methods: A comprehensive literature review was conducted using major academic databases including PubMed, Web of Science, and Google Scholar. A comprehensive search of literature was conducted in PubMed, Web of Science, Google Scholar, and EBSCOhost. The search focused on studies published between 2015 and 2024, supplemented by online reports. The literature was assessed for quality and relevance to malaria prevention, diagnosis, treatment interventions, and socioeconomic factors in Madagascar.

Results: Disparities in malaria prevention and treatment between urban and rural areas are evident, with remote regions experiencing a higher disease burden. Geographic diversity leads to varied transmission patterns, necessitating region-specific interventions. Rural healthcare infrastructure is insufficient for timely diagnosis and treatment. Key interventions include insecticide-treated nets (ITNs), indoor residual spraying (IRS), and seasonal malaria chemoprevention (SMC). Case management primarily uses Artemisinin-based Combination Therapies (ACTs) and rapid diagnostic tests (RDTs). Social and behavior change communication (SBCC) has improved awareness but faces cultural barriers. SMC has shown promise, though logistical challenges remain. Drug resistance and diagnostic failures, along with socioeconomic inequalities, hinder effective malaria control.

Conclusion: To reduce malaria's burden in Madagascar, strengthening healthcare systems, improving supply chains, and expanding prevention efforts in underserved areas are critical. Recommendations include targeting vulnerable groups, enhancing healthcare access, and fostering international collaboration for resource allocation and equitable intervention access. Strategies should emphasize scaling up IRS, ITNs distribution, and SBCC to effectively combat malaria.

International researchers and public health professionals convened in Panama in August 2025 to discuss current and future malaria molecular surveillance strategies to accelerate elimination in the Americas. A new network, MMS Américas, will promote sharing of expertise, protocols, and data.

Background: In 2022, Cameroon was ranked the 11th of the 11 high-burden countries responsible for 70% of the global malaria burden largely due to sustained conflict in the Southwest and Northwest regions since 2018. From May 2021 to April 2024, a mixed-methods study was conducted of three community-based, co-created interventions, a community dialogue approach called the Community Health Participatory Approach (CoHPA), community health workers (CHWs) supportive supervision, and health vouchers for treatment and transportation. The study involved formative, intervention and endline phases; the qualitative findings from the endline evaluation are presented here.

Methods: A qualitative study of 189 host, displaced and returnee participants, involving nineteen focus group discussions (FGDs) with CHWs and separate female and male community groups, and, eighteen in-depth interviews (IDIs), with local councillors, community leaders, supervisors, district, and facility chiefs were conducted. The study compared perceptions of knowledge and attitudes to care-seeking, information and communication channels, community leadership roles and malaria service capacity and quality and care pathway functionality with formative research results. It further evaluated perceptions of the intervention process regarding fidelity, dose, adaptations, process, mediators, reach and recommendations. Data were analysed thematically using NVivo 14.

Results: Communities perceived increased knowledge of malaria prevention and control, with challenges where insecurity reduced facility-based services. Participants described increased participation in community and household prevention activities. CHWs valued supervision. CHW and supervisor support to CoPHA increased trust in CHW services, reducing use of roadside drug sellers. Vouchers increased treatment access, timely referrals, although unsubsidized co-morbidities caused payment challenges. Community leaders questioned voucher sustainability.

Conclusion: Interventions were perceived to have improved prevention and health-seeking awareness and behaviours, community health service utilization and treatment access. Participants felt empowered to create and evaluate solutions.

Background: Progress toward gender equality in the indoor residual spraying (IRS) workforce lags behind other areas of vector control implementation and research. One reason for this may be misconceptions about the cost of implementing IRS with a higher percentage of female staff. The assumption that employing more female spray operators increases costs may stem from the perception that women are less physically capable of performing the demanding work of IRS, resulting in lower productivity and requiring programmes to hire additional staff. The Tchau Tchau Malaria programme in southern Mozambique has achieved high levels of gender equality in its workforce and provides a valuable case study for analysing the impact of gender equality on spray operator salary costs during annual IRS campaigns.

Methods: This study examined data from the 2020/2021 campaign of the Tchau Tchau Malaria programme to understand how employing a high percentage of female spray operators affected the cost of salaries paid to spray operators during the training and implementation phases of the campaign. Salary cost estimates for the actual Tchau Tchau Malaria campaign were compared to a counterfactual scenario assuming a lower percentage of female SOs (30%), consistent with other IRS programmes in sub-Saharan Africa.

Results: Approximately 58.5% of the 2182 spray operators employed by the 2020/2021 Tchau Tchau Malaria campaign were female. Male spray operators were slightly more productive than female spray operators. However, female spray operators were more likely to have worked with previous campaigns; therefore, the average cost of training for female spray operators was lower than the average cost of training for male spray operators. The total salary cost paid to spray operators for the Tchau Tchau Malaria campaign compared with the counterfactual scenario differed by less than 1%.

Conclusions: Analysis of the Tchau Tchau Malaria campaign in Mozambique, when compared to a counterfactual scenario with low gender equality, revealed that achieving a gender-integrated indoor residual spraying workforce had a minimal effect on spray operator salary costs, which represent a significant component of overall IRS programme costs.