Search Results (81)

Megalurothrips usitatus (Bagnall) is a major pest of cowpeas that severely affects their yield and quality. Spinetoram (a semi-synthetic derivative of natural spinosyns, modified to improve potency, residual activity, and stability) is currently one of the primary insecticides used for its control; however, prolonged or repeated exposure to this insecticide may lead to sublethal effects and the development of resistance. This study aimed to clarify the transgenerational effects of sublethal spinetoram stress on the development, reproduction, and population parameters of M. usitatus, with F₄ offspring reared on untreated pods to assess maternal effects. The LC₂₅ of spinetoram against M. usitatus was determined using an improved leaf-tube residual film method, and the thrips were successively selected for three generations (F₁–F₃) at this concentration. An age-stage, two-sex life table was constructed to systematically analyze the developmental duration, adult longevity, fecundity, and population life table parameters of the F₄ generation. The results showed that after three consecutive generations of LC₂₅ stress, the resistance ratio of M. usitatus to spinetoram reached 2.7. Compared with the water control, the F₄ generation from the treated group exhibited significantly shortened 1st and 2nd instar nymphal durations, as well as the total egg-to-adult period, while the prepupal duration was significantly prolonged. Adult longevity in females decreased from 23.65 ± 1.05 days to 16.07 ± 1.40 days (32.1% reduction), and male longevity decreased from 18.78 ± 0.96 days to 15.40 ± 0.82 days (18.0% reduction). Mean fecundity per female decreased from 247.15 ± 30.47 to 34.53 ± 6.02 eggs (86.0% decrease). Regarding population parameters, the net reproductive rate (R₀) decreased from 98.80 ± 0.07 to 10.36 ± 0.01 (89.5% decrease), the intrinsic rate of increase (r) decreased from 0.2506 ± 0.0001 to 0.1452 ± 0.0001 (40.0% decrease), the finite rate of increase (λ) decreased from 1.2849 ± 0.0001 to 1.1564 ± 0.0001 (10.1% decrease), and the mean generation time (T) was shortened from 18.24 ± 0.001 days to 15.84 ± 0.001 days (13.2% reduction). Age-stage-specific life expectancy (e_xj) was significantly reduced across all developmental stages, indicating a shorter survival time. The peak age stage-specific reproductive value (v_xj) was significantly lower and occurred earlier. The peak values of the age-specific survival rate (l_x) and fecundity (f_x, m_x) curves were significantly lower in the treated group. These findings indicate that multigenerational sublethal exposure to spinetoram can induce low-level resistance in M. usitatus and suppress the population growth potential by shortening developmental duration, reducing life expectancy, and reproductive contribution, and significantly inhibiting fecundity and survival. These results reveal the transgenerational sublethal effects of spinetoram and provide a theoretical basis for the integrated pest management (IPM) and resistance control of M. usitatus. Full article

Insecticide-treated nets (ITNs), particularly long-lasting insecticide-treated nets (LLINs), are important for malaria control; however, the rise of insecticide resistance, behavioral adaptations in mosquito vectors, and diminishing net durability may affect their efficacy. The objective of this systematic literature review and meta-analysis to synthesize recent epidemiological evidence (2021–2025) on the correlation between ITN/LLIN use and Plasmodium falciparum infection prevalence and to explore sources of heterogeneity across populations, settings, and type of nets. Searches across PubMed, Scopus, and Web of Science yielded 3151 records, of which 10 met the inclusion criteria. Two separate meta-analyses were performed for crude and adjusted effect estimates using random-effects models. The crude-effects meta-analysis included six studies comprising 7466 participants and yielded a pooled odds ratio of 0.67 (95% CI: 0.42–1.07; p = 0.078), indicating no statistically significant association between ITN/LLIN use and P. falciparum infection. Significant heterogeneity was observed (I² = 79.8%), which was partially explained by population type (59.3%) and study design (36.1%). Subgroup analysis revealed comparable infection prevalence–based associations for ITNs (OR = 0.72) and LLINs (OR = 0.59) use. Assessment of publication bias indicated slight asymmetry; however, the trim-and-fill adjustment did not significantly change the conclusions. The adjusted-effects meta-analysis, comprising nine studies, yielded a non-significant pooled effect (aOR = 0.88; 95% CI: 0.42–1.86; p = 0.71) with substantial heterogeneity (I² = 88.7%). Meta-regression analyses indicated that effect estimates varied by population group and country, with statistically significant modifiers observed for children under five years (p = 0.0098) and for studies conducted in Uganda (p = 0.0378). The type of net contributed to variation between studies, with insecticide-treated nets (ITNs) exhibiting lower pooled odds than long-lasting insecticide-treated nets (LLINs) (p = 0.0415). Overall, this meta-analysis found no conclusive evidence of a statistically significant association between ITN/LLIN use and P. falciparum infection in contemporary epidemiological studies. The substantial heterogeneity across settings underscores the context-dependent nature of observed associations and highlights the need for integrated vector-control strategies and continued evaluation of net technologies under conditions of increasing resistance. Full article

Malaria continues to pose a significant public health challenge in Nigeria, yet there has not been much research utilizing machine-learning techniques to forecast malaria risk. This study developed a machine-learning model that predicts malaria risk by leveraging demographic, environmental, and GPS data from the Nigerian Demographic and Health Survey (DHS) covering the years 2000 to 2020. The dataset was pre-processed and split into a training set (with 406 respondents) and a test set (with 102 respondents). Random Forest (RF), Gradient Boosting (GB) and Linear Regression (LR) algorithms were employed to assess their predictive performance. The RF stood out with the best accuracy, achieving the lowest mean squared error (MSE = 0.0053) and the highest coefficient of determination (R² = 0.6364). Thus, RF was recognized as the most effective model for predicting malaria risk. The regression equation with positive coefficients (like population density = 0.0141, travel time = 0.0019, minimum temperature = 0.0082, temperature in January = 0.0265, and dry land surface temp = 0.0368) indicate that higher feature values are associated with increased malaria prevalence, while negative coefficients (such as rainfall = −0.0122, nightlights composite = −0.03, potential evapotranspiration = −0.09 and insecticide treated nets = −0.02) suggest that as the feature increases, the prevalence decreases. This study underscores the potential of the RF approach in improving early predictions of malaria risk and can guide targeted interventions to control malaria in areas at high risk. Full article

Yellow fever (YF) and malaria co-infections are real public health concerns in Africa, especially in countries such as Nigeria, where mosquitoes carrying both pathogens (Aedes for YF, Anopheles for malaria) coexist. A mathematical model that considers the critical factors influencing the transmission dynamics and control interventions of YF and malaria co-infections is formulated and used to analyse the problem. The essential dynamical features of the model, such as the basic reproduction number and disease-free equilibrium, are determined and analysed. The qualitative analysis of the model illustrates the conditions under which the disease can be eradicated or persists. Further analysis, supported by numerical simulations, reveals the intrinsic dynamics of the model and the impact of control interventions such as yellow fever vaccination, use of insecticide-treated mosquito nets, treatment of malaria-infected humans, and use of insecticides. The results of the analysis demonstrate the impact of interventions; specifically, effective implementations of interventions such as yellow fever vaccination, use of insecticide-treated mosquito nets, and use of insecticides appear to have a significant impact in eradicating YF and malaria co-infections in endemic areas. Effective treatment of malaria-infected humans may lead to a decrease in infections but might not necessarily lead to eradicating infections in endemic areas. These findings are expected to aid in improving the management of YF and malaria co-infections in endemic regions for expeditious disease eradication. Full article

Malaria continues to impose a devastating disease burden globally despite control efforts spanning decades. Its elimination has been hindered by parasite and vector complexity and emerging drug and insecticide resistance, along with unremitting barriers to uptake of preventative strategies largely driven by social inequities, cost constraints, and logistical challenges in implementation. This review synthesises current and emerging prevention strategies, including vector control, chemoprevention and immunoprophylaxis. Insecticide-treated nets and indoor residual spraying remain cornerstones of vector control, although their effectiveness is increasingly compromised by widespread insecticide resistance. Chemoprevention, including intermittent preventive treatment in pregnancy and seasonal malaria chemoprevention in children, has proven highly efficacious, yet uptake remains below WHO targets and concerns about drug resistance remain. Recent advances in vaccines, notably RTS,S/AS01 and R21/Matrix-M, represent landmark achievements, with large-scale rollouts demonstrating reductions in severe disease and mortality. Novel approaches, such as monoclonal antibodies and genetically modified mosquitoes, offer promising avenues for future prevention. However, challenges remain in ensuring equitable access, sustaining efficacy in the face of evolving parasite and vector biology, and integrating interventions into diverse health systems. This review highlights the need for adaptive, multifaceted approaches to achieve malaria elimination goals. Full article

A new generation of insecticide-treated nets (ITNs) that incorporate the synergist piperonyl butoxide (PBO) has been shown to restore susceptibility to pyrethroids where P450 enzymes are the primary mechanism conferring the resistance. The present study evaluated the efficacy of YAHE 4.0, a PBO ITN, against wild free-flying Anopheles arabiensis in experimental huts in Lower Moshi, north-eastern Tanzania. It is the first evaluation of YAHE 4.0 in the country. Bio-efficacy evaluations, including susceptibility tests and cone bioassays, were conducted using the standard WHO guidelines. DuraNet Plus, a WHO-recommended PBO ITN, and Interceptor ITNs served as active and standard comparators, respectively. Unwashed and 20 times washed nets were subjected to experimental hut trials. Multiple logistic regression was employed to analyse experimental hut trial data. The results of the susceptibility testing showed that the An. arabiensis population of Lower Moshi was resistant to pyrethroids, but susceptible to organophosphates. Particularly, low mortality was recorded for cyhalothrin (2%) and alpha-cypermethrin (38%). Mortality rates to alpha-cypermethrin pirimiphos-methyl were 38% and 100%, respectively. The non-inferiority of YAHE 4.0 to DuraNet Plus ITN in terms of mortality and blood feeding was determined according to the WHO guidelines. The results for pooled unwashed and 20 times washed ITNs showed that YAHE 4.0 was superior to Interceptor ITN (adjusted odds ratio, AOR = 1.33; 95% CI = 1.04–1.69; non-inferiority margin, NIM = 0.68; p-value = 0.023) and non-inferior to DuraNet Plus (AOR = 1.02; 95% CI = 0.78–1.35; NIM = 0.72; p-value = 0.867) in terms of mortality. In terms of blood feeding inhibition for pooled unwashed and 20× washed ITNs, YAHE 4.0 was superior to both Interceptor ITN (AOR = 0.80; 95% CI = 0.64–1.00; NIM = 1.35; p-value = 0.049) and DuraNet Plus (AOR = 0.67; 95% CI = 0.52–0.86; NIM = 1.33; p-value = 0.002). Chemical analysis showed higher wash retention of active ingredients in YAHE 4.0 LLIN (88.9% for PBO and 94.9% for alpha-cypermethrin) compared to DuraNet Plus LLIN (89.2% for PBO and 90.5% for alphaypermethrin) before the hut trial. YAHE 4.0 LLIN demonstrated superior entomological efficacy and wash durability to DuraNet Plus and Interceptor LLINs, and fulfilled WHO non-inferiority criteria for mosquito mortality and blood-feeding inhibition. Therefore, YAHE 4.0 LLIN should be considered as an addition to the current list of pyrethroid-PBO nets used for control of pyrethroid-resistant vector populations with P450 enzymes as the main mechanism conferring resistance. Full article

Myzus persicae is a worldwide insect pest with high resistance to many traditional insecticides. Cycloxaprid, a novel cis-configuration neonicotinoid insecticide, is effective in controlling neonicotinoid-resistant insect pests. Lethal and sublethal effects of cycloxaprid on M. persicae were conducted in this study. Results showed that cycloxaprid had higher toxicity to the laboratory and field resistant M. persicae than imidacloprid. Because of the resistance, imidacloprid showed lower control efficacy (<60%) against M. persicae, which falls short of the efficacy required for practical agricultural management. However, cycloxaprid exhibited higher control efficacies (>84.79%) against M. persicae in the field. In addition, in order to quantify the sublethal impacts of cycloxaprid, we conducted a life table analysis on M. persicae. When resistant M. persicae was treated with LC₂₅ of cycloxaprid or imidacloprid, the longevity and fecundity of F₁ adults were significantly decreased. Meanwhile, the intrinsic rate of increase (r_m), finite rate of increase (λ) and net reproduction rate (R_i) of F1 generation M. persicae were reduced in cycloxaprid and imidacloprid treatments. Therefore, cycloxaprid shows high potential as a candidate insecticide for managing imidacloprid-resistant M. persicae. Importantly, our laboratory data indicate that exposure to its low sublethal concentration (LC₂₅) inhibits population growth parameters, suggesting a low risk of inducing pest resurgence under such conditions. Full article

Malaria control in sub-Saharan Africa lies at the intersection of changing climate suitability and the scale-up of vector control and case management. Drawing on recent evidence from Kenya, we argue that climate variability already exerts effects on malaria outcomes comparable to, and sometimes stronger than, those of commonly measured interventions at local scales. Transmission dynamics display non-linear, lagged relationships with temperature and rainfall. As a result, climate change is expected to alter prevailing conditions and extremes, reshaping the geography and seasonality of malaria risk. At the same time, socio-economic development and vector control intervention such as insecticide-treated bed nets (ITNs) and timely case management continue to reduce malaria incidence and deaths, especially among young children. However, their population-level impact depends on when and where interventions are deployed relative to climate-favoured windows of transmission. We propose a practical agenda for “climate-smart” malaria control in Kenya advocating for dynamic targeting of interventions according to observed climate lags and thresholds, sustaining protection for the youngest, and innovating approaches for school-age reservoirs of infection. Access to effective care should be re-conceptualized as a climate-adaptation strategy, and short-term, locally tailored forecasts should be embedded into routine planning to support anticipatory and equitable malaria control. Full article

The cowpea weevil, Callosobruchus maculatus (F.), stands out as one of the most destructive field-to-storage pests of leguminous crops. This study investigates the potential of essential oils derived from two Satureja species, Satureja hortensis L. and Satureja khuzistanica Jamzad, for managing C. maculatus. Bioassay results revealed that both S. hortensis (72 h LC₅₀ = 0.20 µL/g) and S. khuzistanica (72 h LC₅₀ = 0.19 µL/g) essential oils exhibited significant toxicity against C. maculatus adults. The essential oils extended development time, reduced adult longevity, and decreased fecundity of the pest. Key population parameters, including intrinsic growth rate (r) and net reproductive rate (R₀), were significantly lowered, particularly by S. hortensis essential oil. Age-specific survival (l_x) and fecundity (m_x) rates were also declined in treated groups, with delayed reproductive peaks compared to controls. Chemical analyses of S. hortensis and S. khuzistanica essential oils indicated that carvacrol (30.9% and 62.9%, respectively), γ-terpinene (25.5% and 4.3%), p-cymene (9.7% and 7.9%), and thymol (3.7% and 9.3%) were the major components. Hierarchical cluster analysis (HCA) was carried out to compare and contrast the compositions with previous works. The results demonstrated that S. hortensis and S. khuzistanica essential oils, given their lethal and sublethal effects against C. maculatus, can be introduced as natural alternatives to hazardous chemical insecticides, highlighting the need for further research in this field. Full article

Malaria persists as a paradigmatic model of co-evolutionary complexity, emerging from the dynamic interplay among a human host, Anopheles vectors, and Plasmodium falciparum parasites. In human populations, centuries of selective pressures have sculpted an intricate and heterogeneous immunogenetic landscape. Classical adaptations, such as hemoglobinopathies, are complemented by a diverse array of genetic polymorphisms that modulate innate and adaptive immune responses. These genetic traits, along with the acquisition of functional immunity following repeated exposures, mitigate disease severity but are continually challenged by the parasite’s highly evolved mechanisms of antigenic variation and immunomodulation. Such host adaptations underscore an evolutionary arms race that perpetually shapes the clinical and epidemiological outcomes. Intermediaries in malaria transmission have evolved robust responses to both natural and anthropogenic pressures. Their vector competence is governed by complex polygenic traits that affect physiological barriers and immune responses during parasite development. Recent studies reveal that these mosquitoes exhibit rapid behavioral and biochemical adaptations, including shifts in host-seeking behavior and the evolution of insecticide resistance. Mechanisms such as enhanced metabolic detoxification and target site insensitivity have emerged in response to the widespread use of insecticides, thereby eroding the efficacy of conventional interventions like insecticide-treated bed nets and indoor residual spraying. These adaptations not only sustain transmission dynamics in intervention saturated landscapes but also challenge current vector control paradigms, necessitating the development of innovative, integrated management strategies. At the molecular level, P. falciparum exemplifies evolutionary ingenuity through extensive genomic streamlining and metabolic reconfiguration. Its compact genome, a result of strategic gene loss and pruning, is optimized for an obligate parasitic lifestyle. The repurposing of the apicoplast for critical anabolic functions including fatty acid, isoprenoid, and haem biosynthesis highlights the parasite’s ability to exploit host derived nutrients efficiently. Moreover, the rapid accumulation of mutations, coupled with an elaborate repertoire for antigenic switching and epigenetic regulation, not only facilitates immune escape but also accelerates the emergence of antimalarial drug resistance. Advanced high throughput sequencing and functional genomics have begun to elucidate the metabolic epigenetic nexus that governs virulence gene expression and antigenic diversity in P. falciparum. By integrating insights from molecular biology, genomics, and evolutionary ecology, this study delineates the multifaceted co-adaptive dynamics that render malaria a recalcitrant global health threat. Our findings provide critical insights into the molecular arms race at the heart of host–pathogen vector interactions and underscore promising avenues for the development of next generation therapeutic and vector management strategies aimed at sustainable malaria elimination. Full article

The tomato leafminer (Tuta absoluta) is a globally invasive pest that causes severe yield losses in tomato crops. Nanotechnology-based strategies offer promising alternatives to conventional insecticides. This study examines the physiological, biochemical, and demographic responses of T. absoluta following exposure to mesoporous silica nanoparticles (MSNs) applied to tomato leaves at concentrations of 0, 3, 30, and 300 mg L⁻¹. Comprehensive assessments were conducted, including digestive and detoxifying enzyme activities in the insect, neurotoxicity indicators, life table parameters, and antioxidant responses in the host plant. At 30 mg L⁻¹, MSNs significantly impaired larval development, fecundity, and survival of T. absoluta without inducing phytotoxicity. Tomato plants treated at this concentration exhibited enhanced antioxidant enzyme activity (SOD, CAT, POD) and a reduced malondialdehyde (MDA) content, indicating an active oxidative defense. These plant responses were significantly correlated with changes in insect fitness traits, suggesting a plant-mediated effect on pest physiology. Digestive enzyme disruption, decreased acetylcholinesterase activity, and extended developmental periods contributed to suppressed population growth, as evidenced by reductions in the intrinsic rate of increase (r), net reproductive rate (R₀), and fecundity. At 300 mg L⁻¹, however, severe phytotoxicity and enzymatic collapse were observed in both plant and insect systems. These findings highlight moderate concentration of MSNs (30 mg L⁻¹) as a promising dose for sustainable and host-safe pest management, offering multi-targeted suppression of T. absoluta through combined plant and insect biochemical pathways. Full article

Background: Long-lasting insecticidal nets (LLINs) have significantly reduced the malaria burden in recent decades, and this malaria prevalence reduction has been achieved through the upgrading of pyrethroid long-lasting insecticidal nets. However, this reduction has stalled due to many factors, including rapidly developing pyrethroid resistance. Method: The protocol was registered in PROSPERO, and we used Cochrane methodology to assess bias and evidence quality. Three reviewers extracted data from individual studies, and a meta-analysis was performed using Excel and STATA version 17, expressing the data as a risk ratio. Result: A study involving 21,916 households from 11 randomized controlled trials showed that the chlorfenapyr treatment group had a 10% reduction in malaria infection risk, with a pooled overall prevalence of 25.96 per 100 children in the chlorfenapyr group and 32.38 per 100 children in the piperonyl butoxide group, compared to 41.60 per 100 children in the control (pyrethroid-only) group. This meta-analysis determined that the entomological outcomes of effectiveness and efficacy showed that these treatments effectively reduced vector density per household per night and mean inoculation rates, with a 23% reduction in chlorfenapyr, a 7% reduction in pyrethroid-only treatments, and a 12% reduction in piperonyl-butoxide-treated groups. This study shows that chlorfenapyr (CFP) and pyriproxyfen (PPF) LLINs are highly effective and more efficacious in reducing malaria infection, case incidence, and anemia among children, as well as in reducing mean indoor vector density, mean entomological inoculation rate, and sporozoite rate, compared to pyriproxyfen (PPF) LLINs in Africa. Conclusions: This study found that chlorfenapyr (CFP) LLINs are highly effective and more efficacious in reducing malaria infection, case incidence, and anemia among children in Africa. Therefore, policymakers and health planners should place strong emphasis on addressing the effectiveness, efficacy, and resistance management of LLINs as part of their current public health agenda to eliminate malaria. Full article

Malaria, typhoid fever, respiratory tract infections, and urinary tract infections significantly impact women, especially in remote, resource-constrained settings, due to limited access to quality healthcare and certain risk factors. Most studies have focused on vector control measures, such as insecticide-treated nets and time series analysis, often neglecting emerging yet critical risk factors vital for effectively preventing febrile diseases. We address this gap by investigating the use of machine learning (ML) models, specifically extreme gradient boost and random forest, in predicting adult females’ susceptibility to these diseases based on biological, environmental, and socioeconomic factors. An explainable AI (XAI) technique, local interpretable model-agnostic explanations (LIME), was applied to enhance the transparency and interpretability of the predictive models. This approach provided insights into the models’ decision-making process and identified key risk factors, enabling healthcare professionals to personalize treatment services. Factors such as high cholesterol levels, poor personal hygiene, and exposure to air pollution emerged as significant contributors to disease susceptibility, revealing critical areas for public health intervention in remote and resource-constrained settings. This study demonstrates the effectiveness of integrating XAI with ML in directing health interventions, providing a clearer understanding of risk factors, and efficiently allocating resources for disease prevention and treatment. Full article

The private sector in Tanzania has played an essential role in improving coverage and access to mosquito nets. This follow-up study assessed the overall market share for untreated and insecticide-treated nets (ITNs) and misleading or counterfeit ITN products in commercial markets. This study was conducted from March to April 2024 in ten regions in Tanzania. The study used mixed methods: (1) a quantitative survey among sampled outlets supported by photographic documentation of all net products and (2) key informant interviews of retailers and wholesalers. We assessed the relationship between market share and population access using ANOVA and Pearson correlation. No counterfeit or misleading nets were found, consistent with results from 2017, 2021, and 2022 surveys. Untreated nets dominated all markets, comprising 99% of all products observed and 99% of estimated net sales 3 months before the survey. Legitimate ITNs were crowded out from the studied markets. Leaked nets from free distributions were present but extremely limited (1%) and at their lowest level of the survey rounds. Untreated nets were more expensive than leaked ITNs for both regular- and queen-size nets. Despite ongoing efforts, increasing the share of legitimate ITNs remains a significant challenge in a context of large-scale public sector distributions. Full article

Democratic Republic of the Congo (DRC) is among the countries that have a high malaria incidence. In an effort to combat this public health challenge, innovative tools and strategies are being developed and evaluated. Among the new generation of nets with improved effectiveness of insecticides, those treated with a combination of piperonyl butoxide (PBO) and pyrethroids appear to be a promising malaria control tool. This study evaluated the effectiveness of this combination under community conditions of use in the DRC. A quasi-experimental study was carried out from January to December 2018, in Kisantu Health Zone. Thirty villages were randomly allocated as clusters (1:1) to receive one of two types of long-lasting insecticidal nets (LLIN) treated with deltamethrin alone, or PBO with deltamethrin. After the intervention, the assessments were conducted monthly, quarterly, and every six months for malaria infection, mosquito density, and LLIN durability, respectively. Comparison of changes in different indices between the two groups was made using generalized linear models to correct for non-linear effects. A total of 1790 children were included. There was a significant non-linear effect of time (months) on the malaria infection incidence. The malaria infection incidence was higher in January–March, May–June, and November. It remained higher in the control group compared to the intervention group over time. Similarly, there was a significant non-linear effect of time on the density of both Anopheles funestus s.l. and Anopheles gambiae s.l. These densities decreased after the first month following the intervention and increased after 6 months. Twelve months later, a cohort follow-up showed that the bio-efficacy of LLINs was better in the intervention group. The nets treated with the combination of PBO and deltamethrin appear to be more effective for malaria control under community conditions in the DRC, but a loss of chemical durability is noted after the first year of use. Full article