Malaria Vector Research Articles

Non-contact detection of pyrethroids widely used in vector control by Anopheles mosquitoes.

Pyrethroids are the most widely used insecticides to control vector borne diseases including malaria. Physiological resistance mechanisms to these insecticides have been well described, whereas those for behavioral resistance remain overlooked. Field data suggest the presence of spatial sensory detection by Anopheles mosquitoes of the pyrethroid molecules used in insecticide-based control tools, such as long-lasting insecticide nets or insecticide residual spraying. This opens the way to the emergence of a wide range of behavioral adaptations among malaria vectors. However, the spatial sensory detection of these molecules is controversial and needs to be demonstrated. The goal of this study was to behaviorally characterize the non-contact detection of three of the most common pyrethroids used for malaria vector control: permethrin, deltamethrin an ⍺-cypermethrin. To reach this goal, we recorded the behavior (takeoff response) of Anopheles gambiae pyrethroid-sensitive and resistant laboratory strains, as well as field collected mosquitoes from the Gambiae Complex, when exposed to the headspace of bottles containing different doses of the insecticides at 25 and 35°C, in order to represent a range of laboratory and field temperatures. We found the proportion of laboratory susceptible and resistant female mosquitoes that took off was, in all treatments, dose and the temperature dependent. Sensitive mosquitoes were significantly more prone to take off only in the presence of ⍺-cypermethrin, whereas sensitive and resistant mosquitoes showed similar responses to permethrin and deltamethrin. Field-collected mosquitoes of the Gambiae Complex were also responsive to permethrin, independently of the species identity (An. gambiae, An. coluzzii and An. arabiensis) or their genotypes for the kdr mutation, known to confer resistance to pyrethroids. The observed ability of Anopheles spp. mosquitoes to detect insecticides without contact could favor the evolution of behavioral modifications that may allow them to avoid or reduce the adverse effect of insecticides and thus, the development of behavioral resistance.

Bio-efficacy of field aged novel class of long-lasting insecticidal nets, against pyrethroid-resistant malaria vectors in Tanzania: A series of experimental hut trials.

New classes of long-lasting insecticidal nets (LLINs), have been recommended by the World Health Organization (WHO) to control malaria vectors resistant to pyrethroid insecticides. This study was nested in a large-scale cluster-randomized controlled trial conducted (cRCT) in Tanzania. A series of experimental hut trials (EHTs) aimed to evaluate the bio-efficacy of trial LLINs on mosquito indicators most pertinent to malaria transmission over 3 years of use in the community in order to better understand the outcomes of the cRCT. The following field-collected LLINs were assessed: 1) Olyset Plus (combining piperonyl butoxide synergist and permethrin), 2) Interceptor G2 (chlorfenapyr and alpha-cypermethrin), 3) Royal Guard (pyriproxyfen and alpha-cypermethrin), 4) Interceptor (alpha-cypermethrin only) conducted in parallel with 5) a new Interceptor, and 6) an untreated net. Thirty nets of each type were withdrawn from the community at 12, 24, and 36 months after distribution and used for the EHTs. Pre-specified outcomes were 72-hour mortality for Interceptor G2, 24-hour mortality for Olyset Plus, and fertility based on egg development stage for Royal Guard. Overall, Interceptor G2 LLINs induced higher 72-hour mortality compared to standard LLINs of the same age up to12 months (44% vs 21%, OR: 3.5, 95% CI: 1.9-6.6, p-value < 0.001), and 24-hour mortality was only significantly higher in Olyset Plus when new (OR: 13.6, 95%CI: 4.4-41.3, p-value < 0.001) compared to standard LLINs but not at 12 months (17% vs 13%; OR: 2.1, 95% CI: 1.0-4.3; p-value = 0.112). A small, non-significant effect of pyriproxyfen on Anopheles fertility was observed for Royal Guard up to 12 months (75% vs 98%, OR: 1.1, 95% CI: 0.0-24.9, p-value = 0.951). There was no evidence of a difference in the main outcomes for any of the new classes of LLINs at 24 and 36 months compared to standard LLINs. Interceptor G2 LLINs showed superior bio-efficacy compared to standard LLINs only up to 12 months, and the effect of Olyset Plus was observed when new for all species and 12 months for An. gambiae s.l. only. The pyriproxyfen component of Royal Guard had a short and limited effect on fertility. The decrease in effectiveness of Olyset Plus and Royal Guard LLINs in the EHTs aligns with findings from the cRCT, whereas efficacy of Interceptor G2 lasted for a longer period in the cRCT compared to the EHT. Further investigations are needed to understand the complete scope of chlorfenapyr mode of action. Additional EHT in various contexts will help confirm the residual efficacy of the dual active ingredient LLINs and support the development of longer-lasting nets.

The first complete mitochondrional genome of Anopheles gibbinsi using a skimming sequencing approach.

Mosquitoes belonging to the genus Anopheles are the only vectors of human malaria. Anopheles gibbinsi has been linked to malaria transmission in Kenya, with recent collections in Zambia reporting the mosquito species exhibiting zoophilic and exophilic behavioral patterns with occasional contact with humans. Given the paucity of genetic data, and challenges to identification and molecular taxonomy of the mosquitoes belonging to the Anopheles genus; we report the first complete mitochondrial genome of An. gibbinsi using a genome skimming approach. An Illumina Novaseq 6000 platform was used for sequencing, the length of the mitochondrial genome was 15401 bp, with 78.5% AT content comprised of 37 genes. Phylogenetic analysis by maximum likelihood using concatenation of the 13 protein coding genes demonstrated that An. marshallii was the closest relative based on existing sequence data. This study demonstrates that the skimming approach is an inexpensive and efficient approach for mosquito species identification and concurrent taxonomic rectification, which may be a useful alternative for generating reference sequence data for evolutionary studies among the Culicidae.

An observational study assessing distribution of mosquito bites on humans to inform personal protection measures against malaria and dengue vectors

An observational study assessing distribution of mosquito bites on humans to inform personal protection measures against malaria and dengue vectors

Involvement of two major vectors of malaria, Anopheles gambiae Giles and An nili Theobald (Diptera: Culicidae), in Plasmodium falciparum transmission of two coastal villages of Côte d’Ivoire

Involvement of two major vectors of malaria, Anopheles gambiae Giles and An nili Theobald (Diptera: Culicidae), in Plasmodium falciparum transmission of two coastal villages of Côte d’Ivoire

Species composition, infection rate and feeding preference of Anopheles mosquito species (Diptera: Culicidae) in the west Amhara Region, northwest Ethiopia.

Reports showed that Amhara Region is accounting for 31% of Ethiopia`s malaria burden. Reports also depicted that despite the existing malaria vector control tools implemented by the regional government, currently there is an increment in malaria prevalence in the region. This might be due to lack of entomological monitoring and comprehensive information on the prevailing species composition, infection rate and feeding presences of An. mosquito species in the study areas. Therefore, this study aimed to address this information. A community-based cross-sectional study was conducted from 18 February to 30 March 2023 at three districts of the west Amhara Region. For this, six CDC light traps (three indoor and three outdoor) were used to collect adult female An. mosquito species. In this study, 261 An. mosquito species comprising seven species were collected. Their morphological identification and abdominal status determination were carried out using standard morphological identification keys under a dissection microscope. While their infection rates and blood meal sources were determined, using circumsporozoite protein-ELISA and blood meal-ELISA based on the standard protocol. Data were entered to SPSS versions 20 for analysis and p- value < 0.05 was considered as statistically significant. In our study, total of 261 An. mosquito species were identified. An. demeilloni was the most abundant species accounted for 112(42.9%) of all captures. It was also the most predominant species at Ayehu-Guagusa followed by Jabitehnan districts. An. demeilloni and An. cinereus altogether accounting for infection rate of 3(1.1%) for P. vivax parasite. Furthermore, our study showed that more than 50% of An. mosquito species collected fed on cattle blood showing shifting of feeding behaviors. Our study depicted that An. demeilloni and An. cinereus were the most abundant species and infected with P. vivax parasite. Therefore, further comprehensive study should be done in the future.

Distribution, survivability and susceptibility status of Anopheles mosquitoes in Kamamaung Township, Kayin State in Myanmar

Malaria endemicity is remaining in hard to reach and insurgent areas in Myanmar, where high density of primary and secondary vectors are available. Present study was determined the distribution, survivability and insecticides susceptibility status of vectors and non-vectors of malaria in Katinehtit village Kamamaung Township, Kayin State from July 2020 to June 2021. Mosquitoes were collected by Kanda net for animal bait and CDC light traps for indoor and outdoor collection from 18:00 to 00:06 hour. Survivability rate of An. dirus, An. minimu, An. aconitus, An. philippinensis, An. vagus and An. culicifacies were measured under the group of banana plants and susceptibility of collected mosquitoes were tested with WHO recommended insecteds. A total of 2207 mosquitoes consist of 13 Anopheles mosquito adult were collected by different collection methods by Cattle bate 1581(71.64%), Light trap indoor 174(7.88%), Light trap outdoor 297(13.46%), Morning Resting 43(1.95%) and Near the resting plant 112(5.07). Main vector An. dirus and An. minimus were mostly collected in Rainey season in high density and An. dirus was disappeared in hot season. Main vector An. minimus and secondary vector as An. philippinensis, An. culicifacies, An. maculatus, An. aconitus and nan vector An. barbirostris and An. hyrcanus were collected in all seasons. An. philippinensis, An. barbirostris and An. hyrcanus were abundantly collected. The highest survivability rate was found An. dirus and An. vagus for 8 days (10%) followed by An. culicifacies (20%), An. philippinensis (10%), An. minimus (20%) for 7 days and lowest was found An. aconitus for 6 days (20%). High density of An. dirus larvae were collected from rock pools and An. minimus was collected in sand pools, rice fields water, bed of Yonsalin creeks and water pools. All the collected mosquitoes were susceptible to Deltamethrin 0.05%, Permethrin 0.75% and Cyfuthris 0.15%. In conclusion, high density of main malaria vectors and secondary vectors were collected from Katinehtit village is a high risk area of malaria. Although all the collected main and secondary vectors were susceptible to WHO recommended insecticides. Therefore, Long Lasting Insecticide impregnated nets can be preventing the transmission of malaria in this area.

Malaria Vectors Tend to Avoid the Indoor-Based Vector Control Tools in Wonji Sugar Estate, Oromia, Ethiopia

Malaria Vectors Tend to Avoid the Indoor-Based Vector Control Tools in Wonji Sugar Estate, Oromia, Ethiopia

First Observations of Plasmodium malariae on the Long-Term Malaria Vector Control Program on Villages of the Balombo Region of Angola

First Observations of Plasmodium malariae on the Long-Term Malaria Vector Control Program on Villages of the Balombo Region of Angola

Species abundance and density of malaria vectors in Western Thailand and implications for disease transmission

Understanding the dynamics of malaria vectors and their interactions with environmental factors is crucial for effective malaria control. This study investigated the abundance, species composition, seasonal variations, and malaria infection status of female mosquitoes in malaria transmission and non-transmission areas in Western Thailand. Additionally, the susceptibility of malaria vectors to pyrethroid insecticides was assessed. Entomological field surveys were conducted during the hot, wet, and cold seasons in both malaria transmission areas (TA) and non-transmission areas (NTA). The abundance and species composition of malaria vectors were compared between TA and NTA. The availability of larval habitats and the impact of seasonality on vector abundance were analyzed. Infection with Plasmodium spp. in primary malaria vectors was determined using molecular techniques. Furthermore, the susceptibility of malaria vectors to pyrethroids was evaluated using the World Health Organization (WHO) susceptibility test. A total of 9799 female mosquitoes belonging to 54 species and 11 genera were collected using various trapping methods. The number of malaria vectors was significantly higher in TA compared to NTA (P < 0.001). Anopheles minimus and An. aconitus were the predominant species in TA, comprising over 50% and 30% of the total mosquitoes collected, respectively. Seasonality had a significant effect on the availability of larval habitats in both areas (P < 0.05) but did not impact the abundance of adult vectors (P > 0.05). The primary malaria vectors tested were not infected with Plasmodium spp. The WHO susceptibility test revealed high susceptibility of malaria vectors to pyrethroids, with mortality rates of 99–100% at discriminating concentrations. The higher abundance of malaria vectors in the transmission areas underscores the need for targeted control measures in these regions. The susceptibility of malaria vectors to pyrethroids suggests the continued effectiveness of this class of insecticides for vector control interventions. Other factors influencing malaria transmission risk in the study areas are discussed. These findings contribute to our understanding of malaria vectors and can inform evidence-based strategies for malaria control and elimination efforts in Western Thailand.

Impact of blood meals taken on ivermectin-treated livestock on survival and egg production of the malaria vector Anopheles coluzzii under laboratory conditions.

Treatment of livestock with endectocides such as ivermectin is viewed as a complementary vector control approach to address residual transmission of malaria. However, efficacy of this treatment may vary between animal species. Hence, our purpose was to investigate the effects of ivermectin treatments of common livestock species on life history traits of the opportunistic malaria vector Anopheles coluzzii. Sheep, goats and pigs were treated using injectable veterinary ivermectin formulation at the species-specific doses (recommended dose for all species and high dose in pig). Mosquito batches were exposed to treated and control (not injected) animals at different days after treatment. Daily mosquito mortality was recorded and fecundity assessed through the count of gravid females and the number of eggs they developed. The recommended dose of ivermectin induced a significant decrease in mosquito survival for up to 7 days after injection (DAI), with a decrease of 89.7%, 66.7%, and 48.4% in treated pigs, goats and sheep, respectively, compared to control animals. In treated pigs, the triple therapeutic dose decreased mosquito survival of 68.97% relatively to controls up to 14 DAI. The average number in gravid females Anopheles that survived after feeding on treated animals were reduced when blood-meals were taken on sheep (2.57% and 42.03% at 2 and 7 DAI), or on goats (decrease of the 28.28% and 73.64% respectively at 2 and 7 DAI). This study shows that ivermectin treatments to animals negatively impacts An. coluzzii life history traits and could reduce vector densities in areas where livestock live near humans. However, due to short-term efficacy of single dose treatments, repeated treatments and potentially increased dosages would be required to span the transmission season. The use of long-acting ivermectin formulations is discussed as a mean for extending efficacy while remaining cost effective.

Generation of specific immune memory by bacterial exposure in the major malaria vector Anopheles arabiensis (Diptera: Culicidae)

There is a growing body of evidence that invertebrates can generate improved secondary responses after a primary challenge. This immunological memory can be primed by a range of pathogens, including bacteria. The generation of immunological memory has been demonstrated in mosquitoes, with the memory primed by a range of initial stimuli. This study aimed to examine whether insecticide resistance affects the capacity to generate immunological memory. The primary hypothesis was tested by examining the capacity of genetically related laboratory-reared Anopheles arabiensis strains that differ by insecticide resistant phenotype to generate immunological memory. The competing hypothesis tested was that the bacterial virulence was the key determinant in generating immunological memory. Immune memory was generated in F1 females but not males. Immunological memory was demonstrated in both laboratory strains, but the efficacy differed by the insecticide resistant phenotype of the strain. An initial oral challenge provided by a blood meal resulted generated better memory than an oral challenge by sugar. The efficacy of memory generation between the two bacterial strains differed between the two mosquito strains. Regardless of the challenge, the two strains differed in their capacity to generate memory. This study therefore demonstrated that insecticide resistant phenotype affected the capacity of the two strains to generate immunological memory. Although this study needs to be replicated with wild mosquitoes, it does suggest that a potential role for insecticide resistance in the functioning of the immune system and memory generation of An. arabiensis.

Mosquito Control Strategies and Insecticide Resistance of the Malaria Vector in Urbanized Land Use Types in Suame Municipality, Ghana.

Modified landscapes could create breeding habitats for mosquitoes and affect their community structure and susceptibility with implications for their management. Hence, in this study, household mosquito control methods in two urbanized landscapes; industrial and residential human settlements, in Ghana and insecticide susceptibility of the inhabiting Anopheles populations were assessed. Household knowledge and usage pattern of mosquito control methods in the modified landscapes were obtained using a questionnaire. Female adult Anopheles mosquitoes were also subjected to susceptibility tests using mosquito coils (0.08% meperfluthrin, 0.03% dimefluthrin, and 0.3% transfluthrin) and World Health Organization (WHO) insecticide test papers (0.05% deltamethrin, 4% DDT, 0.1% bendiocarb, 0.25% pirimiphos-methyl, and 5% malathion). Although insecticide-treated nets and aerosols were used for mosquito control, mosquito coils were the most common and widely preferred household method. The Anopheles mosquitoes were resistant to all the insecticides (mosquito coils and WHO test papers) except pirimiphos-methyl. Land use type did not affect insecticide resistance, but the insecticide type did. The findings indicate the effect of household insecticide usage practices on local mosquito populations and their implications for effective vector management and disease control in modified landscapes.

Kenya must wake up to the threat of cryptic Anopheles species and their impact on residual malaria transmission.

Malaria remains a major health problem in Kenya despite the huge efforts put in place to control it. The non-relenting malaria threat has partly been attributed to residual malaria transmission driven by vectors that cannot effectively be controlled by the two popularly applied control methods: long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS). Reports indicate that residual transmission is widely spread in areas where malaria is endemic. This could mean that the World Health Organization's vision of a world free of malaria remains a mirage as elimination and prevention of re-establishment of malaria are rendered unachievable. Amongst the major contributors to residual malaria transmission are cryptic rare species, species of mosquitoes that are morphologically indistinguishable, but isolated genetically, that have not been the focus of malaria control programs. Recent studies have reported extensive new Anopheles cryptic species believed to be involved in malaria transmission in Kenya. This underscores the need to understand these malaria vector species, their distribution and bionomics and their impact on malaria transmission. This article discusses reports of these cryptic species, their importance to malaria transmission, especially in the arid and semi-arid areas, and what can be done to mitigate the situation.

Laboratory and Semi-Field Evaluation on S-Methoprene Formulations Against Anopheles sinensis (Diptera: Culicidae) - Yuxi City, Yunnan Province, China.

Anopheles sinensis (An. sinensis) is the predominant malaria vector in China. The impact of S-methoprene on the emergence process of mosquito larvae suggests its potential as a control method for vector mosquitoes. However, the efficacy of S-methoprene in controlling An. sinensis has not yet been demonstrated. The effectiveness of S-methoprene against An. sinensis was assessed in laboratory and semi-field conditions in Yunnan Province. These results offer valuable options and guidance for utilizing S-methoprene products in malaria reimportation prevention areas within Yunnan Province.

Plant-based nanoparticles targeting malaria management.

Malaria is one of the most devastating diseases across the globe, particularly in low-income countries in Sub-Saharan Africa. The increasing incidence of malaria morbidity is mainly due to the shortcomings of preventative measures such as the lack of vaccines and inappropriate control over the parasite vector. Additionally, high mortality rates arise from therapeutic failures due to poor patient adherence and drug resistance development. Although the causative pathogen (Plasmodium spp.) is an intracellular parasite, the recommended antimalarial drugs show large volumes of distribution and low-to no-specificity towards the host cell. This leads to severe side effects that hamper patient compliance and promote the emergence of drug-resistant strains. Recent research efforts are promising to enable the discovery of new antimalarial agents; however, the lack of efficient means to achieve targeted delivery remains a concern, given the risk of further resistance development. New strategies based on green nanotechnologies are a promising avenue for malaria management due to their potential to eliminate malaria vectors (Anopheles sp.) and to encapsulate existing and emerging antimalarial agents and deliver them to different target sites. In this review we summarized studies on the use of plant-derived nanoparticles as cost-effective preventative measures against malaria parasites, starting from the vector stage. We also reviewed plant-based nanoengineering strategies to target malaria parasites, and further discussed the site-specific delivery of natural products using ligand-decorated nanoparticles that act through receptors on the host cells or malaria parasites. The exploration of traditionally established plant medicines, surface-engineered nanoparticles and the molecular targets of parasite/host cells may provide valuable insights for future discovery of antimalarial drugs and open new avenues for advancing science toward the goal of malaria eradication.

In silico studies of benzothiazole derivatives as potential inhibitors of Anopheles funestus and Anopheles gambiae trehalase.

In malaria management, insecticides play a crucial role in targeting disease vectors. Benzothiazole derivatives have also been reported to possess insecticidal properties, among several other properties they exhibit. The female Anopheles mosquito is responsible for transmitting the malaria parasite when infected. Anopheles gambiae (Ag) and Anopheles funestus (Af) are two of the most notable Anopheles species known to spread malaria in Nigeria. Trehalase is an enzyme that breaks down trehalose. Recent research has proposed it as a viable target for inhibition since it aids in flight and stress adaptation. This study aimed to investigate benzothiazole derivatives as potential inhibitors of trehalase of Anopheles funestus (AfTre) and Anopheles gambiae (AgTre) using toxicity profiling, molecular docking, and dynamic simulation for future insecticidal intervention. A total of 4,214 benzothiazole-based compounds were obtained from the PubChem database and subjected to screening against the 3D modelled structure of AfTre and AgTre. Compounds with some toxicity levels were optimised, and the obtained lead compounds were further investigated through molecular docking studies. Furthermore, the best hit was subjected to parameters such as RMSD, RMSF, SASA, Rg, and hydrogen bond to confirm its stability when in a complex with AfTre, and these parameters were compared to that of validamycin A (control ligand). The post-screening analysis showed binding affinities of -8.7 and -8.2kcal/mol (compound 1), -8.2 and -7.4kcal/mol (compound 2), compared to -6.3 and -5.1kcal/mol (Validamycin A, a known inhibitor) against AfTre and AgTre, respectively. The molecular dynamics simulation showed that compound 1 (the best hit) had good stability when in complex with AfTre. These findings suggest that these best hits can serve as potential inhibitors for the development of novel insecticides in the control of malaria vectors.

Combination of computational techniques and RNAi reveal targets in Anopheles gambiae for malaria vector control.

Increasing reports of insecticide resistance continue to hamper the gains of vector control strategies in curbing malaria transmission. This makes identifying new insecticide targets or alternative vector control strategies necessary. CLassifier of Essentiality AcRoss EukaRyote (CLEARER), a leave-one-organism-out cross-validation machine learning classifier for essential genes, was used to predict essential genes in Anopheles gambiae and selected predicted genes experimentally validated. The CLEARER algorithm was trained on six model organisms: Caenorhabditis elegans, Drosophila melanogaster, Homo sapiens, Mus musculus, Saccharomyces cerevisiae and Schizosaccharomyces pombe, and employed to identify essential genes in An. gambiae. Of the 10,426 genes in An. gambiae, 1,946 genes (18.7%) were predicted to be Cellular Essential Genes (CEGs), 1716 (16.5%) to be Organism Essential Genes (OEGs), and 852 genes (8.2%) to be essential as both OEGs and CEGs. RNA interference (RNAi) was used to validate the top three highly expressed non-ribosomal predictions as probable vector control targets, by determining the effect of these genes on the survival of An. gambiae G3 mosquitoes. In addition, the effect of knockdown of arginase (AGAP008783) on Plasmodium berghei infection in mosquitoes was evaluated, an enzyme we computationally inferred earlier to be essential based on chokepoint analysis. Arginase and the top three genes, AGAP007406 (Elongation factor 1-alpha, Elf1), AGAP002076 (Heat shock 70kDa protein 1/8, HSP), AGAP009441 (Elongation factor 2, Elf2), had knockdown efficiencies of 91%, 75%, 63%, and 61%, respectively. While knockdown of HSP or Elf2 significantly reduced longevity of the mosquitoes (p<0.0001) compared to control groups, Elf1 or arginase knockdown had no effect on survival. However, arginase knockdown significantly reduced P. berghei oocytes counts in the midgut of mosquitoes when compared to LacZ-injected controls. The study reveals HSP and Elf2 as important contributors to mosquito survival and arginase as important for parasite development, hence placing them as possible targets for vector control.

Lessons on malaria vector control from Bashful, Doc, Dopey, Grumpy, Happy, Sneezy, and Sleepy.

Despite significant advancements in vector control, malaria continues to expand and claim hundreds of thousands of lives annually. A 1943 animated film by Walt Disney remains a poignant reminder of the ongoing challenge and a good example of interventions that have fallen off the pages of history. It underscores two key points. First, the importance of proactive mosquito control measures and the need for comprehensive strategies targeting mosquitoes at every stage of their life cycle. Second, collaboration between all stakeholders and sustained investment are vital for success in malaria control. Manuel Llu-beras is a public health entomologist renowned globally for assembling the business architecture of mosquito population management initiatives in four continents. He crafted the first WHO Operational Manual for Indoor Residual Spraying (IRS) and played a pivotal role in designing the structure of the IRS campaign of the US President's Malaria Initiative and several mineral extraction companies. He served in several post-event emergency mosquito control operations. Prior to establishing Mosquito Den LLC in 2021, he was Executive Director for Public Health for H.D. Hudson Manufacturing from 1996 through 2022. He served as medical entomologist for the US Navy a dozen years. His contributions to public health entomology were recognised with the Global Trade Award from the Global Trade Chamber, the Meritorious Service Award of the American Mosquito Control Association, and two nominations for the Rear Admiral Charles S. Stevenson Award for excellence in US Navy Preventive Medicine.

Larvicidal activity of CuO and ZnO nanoparticles against Aedes aegypti and Anopheles stephensi mosquito vectors-a greener approach by Phaseolus vulgaris L. aqueous extract as bio-reductant

In order to eradicate mosquito-borne diseaseslikemalaria,chikungunya, dengue,and Zika virus which are mostly found in temperate zones, synthetic pesticides are widely used as a form of fumigation. This has resulted in a rise in mosquito-borne disease transmission dynamics and a substantial rise in atmospheric pollution. In light of this, the current work used an aqueous extract of Phaseolus vulgaris to formulate bioencapsulated CuO and ZnO NPs to combat mosquito vectors. The synthesized CuO and ZnO NPs were characterized using UV–visible, XRD, FT-IR, FE-SEM & EDX, AFM, and DLS techniques. According to analytical characterization, the CuO and ZnO NPs had monoclinic and hexagonal crystallites with average sizesof 13.7 nm and 185 nm, respectively. FE-SEM analysis confirms the spherical and flower-like morphology of CuO and ZnO NPs and their respective elemental composition was identified by EDX studies. The average particle size of CuO and ZnO NPs was determined to be 22.6 nm and 662 nm. CuO and ZnO NPs possessed zeta potential values of −23.2 mV and −29.7 mV respectively. The larvae of the malaria vector Anopheles stephensi and the dengue vector Aedes aegypti were subjected to compare the larvicidal bioassays in a range of concentrations of P. vulgaris aqueous extract with methanol extracts, and CuO NPs with ZnO NPs (6.25, 12.5, 25, 50, 100 µg/mL). The results showed the larvicidal activity of the aqueous extract is superior to the methanol extract and ZnO NPs are superior to the CuO NPs. This study further revealed that Aedes aegypti vulnerable than Anopheles stephensi to a given concentration of crude aqueous, methanol extracts of P. vulgaris and to CuO and ZnO NPs. The overall findings of this research demonstrated the feasibility of using these biosynthesized nanoparticles as highly effective, eco-friendly natural mosquito control pesticides.