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Mosquitoes serve as the major vector transmitting malaria, dengue, yellow fever and several other diseases of human concern. Rising in mosquito-borne diseases and consequent fatalities throughout the world has made the management of mosquitoes of paramount importance. With the use of various insecticidal agents and their indiscriminate application in the fields for vector control; other issues such as multiple insecticide resistance, lethality to non-specific targets and adverse effects on human and environmental health have emerged making the situation more critical. Hence, the focus of researchers has diverted to the use of Insect Growth Regulators (IGRs) that affect the growth and development of the insects without inducing any appreciable toxic effects. The paper comprehensively reviews various IGRs and their potential use against insect pests and mosquito vectors. A special emphasis has been laid on the utilization of diflubenzuron, its larvicidal potency and growth regulatory effects against mosquitoes. The paper also delivers a detailed discussion on various approaches governing with the application of diflubenzuron, a chitin synthesis inhibitor, for its potent effects over a wide range of other insect species, low toxicity to humans, safety to other non-target animals, negligible deleterious environmental impact along with the possible development of resistance in the mosquitoes, thereby providing insights and the direction for the future in terms of the innovative and technological perspective. Keeping in view the role of multifarious mechanisms in the development of resistance; use of various synergistic compounds, such as hydrolase inhibitors - profenofos and S,S,S-tributyl phosphorotrithioate; glutathione S-transferase inhibitor – diethylmaleate; and oxidase inhibitor - piperonyl butoxide (PBO); has been recommended in combination with IGRs to enhance their efficacy, and reduce or reverse the resistance in target mosquitoes. Another compound, verapamil, has been found extremely efficient in imparting synergistic effect to diflubenzuron by inhibiting P-glycoproteins, a transporter of the insecticides causing their efflux from the cell. Recommendations have been made for safe and effective mosquito control measures, adequate policies and increased awareness about the mosquito-borne diseases among the masses. In addition, regular surveillance of mosquitoes is endorsed for the formulation of an efficient mosquito management strategy.

The aim of this study was to analyze the prevention and control practices against Zika virus (ZIKV) infection among pregnant women in Malaysia. A cross-sectional study was conducted among pregnant women who received antenatal care. Only 7.8% reported that they abstained from sex or used barrier methods during sexual intercourse to prevent ZIKV transmission. The odds of abstaining from sex or using barrier methods were significantly higher among the Chinese ethnic group than the Malay ethnic group (odds ratio [OR] = 4.569; 95% confidence interval [CI]: 2.696-7.743). A total ZIKV knowledge score of 12-24 was also significantly associated with higher odds of abstaining from sex or using barrier methods than a score of 0-11 (OR = 2.819; 95% CI: 1.682-4.725). In total, 38.6% of women had a higher mean total score for all the current mosquito control practices than they did before hearing of ZIKV. Participants living in bungalows or village houses (OR = 2.006; 95% CI: 1.023-3.936) and low-rise houses (OR = 1.566; 95% CI: 1.109-2.212) were more likely to have a higher mean total score of current mosquito control practices than the practices before hearing of ZIKV compared to those in high-rise houses. The lack of ZIKV knowledge and control practices provides insight for the pre-emptive and prompt development of health education systems for pregnant women during antenatal care visits.

Background: Aedes aegypti is the primary dengue vector, a significant public health problem in many countries. Controlling the growth of Ae. aegypti is the biggest challenge in the mosquito control program, and there is a need for finding bioactive molecules to control Ae. aegypti in order to prevent dengue virus transmission. Objective: To assess the mosquitocidal property of lawsone and its 3-methyl-4H-chromen-3-yl-1-phenylbenzo[6,7]chromeno[2,3,c]pyrazole-dione derivatives (6a-6h) against various life stages of Ae. aegypti. Besides, to study the mode of action of the active compound by molecular docking and histopathological analysis. Methods: All derivatives were synthesized from the reaction between 2-hydroxy-1,4-naphthoquinone, chromene-3-carbaldehyde, and 1-phenyl-3-methyl-pyrazol-5-one by using one pot sequential multicomponent reaction. The mosquito life stages were subjected to diverse concentrations ranging from 1.25, 2.5, 5.0, and 10 ppm for lawsone and its derivatives. The structure of all synthesized compounds was characterized by spectroscopic analysis. Docking analysis was performed using autodock tools. Midgut sections of Ae. aegypti larvae were analyzed for histopathological effects. Results: Among the nine compounds screened, derivative 6e showed the highest mortality on Ae. aegypti life stages. The analyzed LC50 and LC90 results of derivative 6e were 3.01, 5.87 ppm, and 3.41, 6.28 ppm on larvae and pupae of Ae. aegypti, respectively. In the ovicidal assay, the derivative 6e recorded 47.2% egg mortality after 96-hour post-exposure to 10 ppm concentration. In molecular docking analysis, the derivative 6e confirmed strong binding interaction (-9.09 kcal/mol and -10.17 kcal/mol) with VAL 60 and HIS 62 of acetylcholinesterase 1 (AChE1) model and LYS 255, LYS 263 of kynurenine aminotransferase of Ae. aegypti, respectively. The histopathological results showed that the derivative 6e affected the columnar epithelial cells (CC) and peritrophic membrane (pM). Conclusion: The derivative 6e is highly effective in the life stages of Ae. aegypti mosquito and it could be used in the integrated mosquito management programme.

Background The house mosquito, Culex pipiens L. is a harmful species, widespread in urban areas, and considered the primary enzootic vector of West Nile arbovirus. Widespread insecticide resistance in mosquito populations and the environmental risks and toxicity hazards of chemical pesticides make insecticides an inadequate mosquito control strategy. Seeking ecofriendly tools for mosquito control tools has become necessary. Results Essential oil (EO) was hydrodistilled from the fruits of Brazilian pepper, Schinus terebinthifolius Raddi and analyzed using gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. An oil-in-water nanoemulsion (particle size 41.3 nm) was developed and characterized from EO using a green low-energy approach. EO, its nanoemulsion and monoterpenes showed mosquitocidal, repellent and acetylcholinesterase inhibitory activities against Cx. pipiens. A nanoemulsion concentration of 30 μl L-1 caused 100% larval mortality after 24 h of exposure, whereas EO, d-limonene and α-phellandrene at 60 μl L-1 caused 100%, 92.4% and 88.2% larval mortality, respectively. The concentration that killed 50% of organisms (LC50 ) for larvae after 24 h ranged between 6.8 and 40.6 μl L-1 . Upon fumigation, 15.0 μl L-1 of nanoemulsion killed 94.5% of adults after 24 h of exposure. LC50 values against adults ranged between 5.3 and 31.2 μl L-1 . EO products exhibited repellence activity at concentrations between 0.5 and 4.0 μl cm-2 . Test materials effectively inhibited the acetylcholinesterase activity of mosquito and were safe toward the non-target organisms Gambusia affinis and Eisenia fetida. Conclusion There is a potential for using S. terebinthifolius EO, its nanoemulsion and monoterpenes as ecofriendly natural mosquitocides.

Mosquito collections are commonly conducted with baited traps predominantly attracting host-seeking females. In contrast, resting sites are generally colonized by a broader range of the mosquito population, including a higher proportion of males and blood-engorged females. This study evaluates the sampling success of different artificial resting sites, attached to a deciduous or coniferous tree at different heights. As standard sampling method, carbon dioxide-baited Biogents Sentinel traps (BG traps) were operated in parallel. BG traps caught a higher number of specimens compared to the resting sites. However, the proportion of blood-engorged females and males was higher in resting sites. More Culiseta spp. specimens were collected in resting sites compared to BG traps, but less Aedes spp. specimens. In general, fewer specimens and species were recorded in small resting sites and at top height level compared to medium or large resting sites at medium or ground level. The proportion of males was highest at the ground, while the proportion of engorged females was highest at medium and top level. Due to the higher proportion of blood-engorged females, artificial resting sites are especially useful for studies of host-feeding patterns or xenosurveillance. Low costs and efforts allow a cost-effective increase of the number of resting sites per sampling site to collect more mosquitoes.

Since 2011, the Florida Keys Mosquito Control District (FKMCD) has used the WALS® application strategy with VectoBac® WDG containing Bacillus thuringiensis israelensis via helicopter in Key West for the control of Aedes aegypti larval populations. In 2018, FKMCD conducted a study to determine the effectiveness of using a trailer-mounted A1 Super Duty Mist Sprayer® (A1 Mist Sprayers) with a Micronair® AU5000 (Micron Group) atomizer to apply VectoBac WDG by ground at the rate of 0.5 lb/acre (0.56 kg/ha). Bioassay cups were placed in a residential area encompassing open, moderate, and heavy cover scenarios between 0 and 300 ft (0–91.44 m) perpendicular to the spray line. An application rate of 0.5 lbs/acre (0.56 kg/ha) was used. Bioassay cups were collected after application and returned to the laboratory where 100 ml of distilled water and 10 F1 generation Ae. aegypti larvae were added. Laval mortality was monitored at 2, 4, and 24 h. Three separate runs were completed during the summer of 2018. Average larval mortality at 24 h was >90%. The field trial demonstrated sufficient efficacy to introduce this method of larviciding into operational use.

Aedes vexans is known to occur in large populations in riverine floodplains in much of Europe, where it can cause a significant biting nuisance and is often subject to large scale control strategies. Until recently it had only been reported in very small numbers in the United Kingdom. After receiving reports of nuisance biting near the river Idle, Nottinghamshire (East Midlands, England), mosquito surveillance was conducted over three years (2018-2020) using Mosquito Magnet adult traps. Ae. vexans was found in all years, in very high numbers, particularly in 2020, reaching a peak of almost 5,000 female mosquitoes per trap night, the highest reported density of trapped adult mosquitoes in the UK. Larval control was conducted in all years, and adult control in one year, however local peculiarities of flood and water management presents challenges and necessitates a multi-faceted approach. Strategies for further expansion of the control operation by developing strategies for water management, coupled with larval surveys to define the extent and seasonality of larval habitats, and application methods of Bacillus thuringiensis israelensis products are discussed.

Vector-borne diseases such as filariasis and dengue that contribute significantly to disease burden, death, poverty, and social frailty are still a major public healthcare problem worldwide. Currently, synthetic chemicals have been used in mosquito control programs. However, repeated use of chemical insecticides causes environmental pollution and harmful effects on non-target organisms. Therefore, alternative ecofriendly sources from biological source are urgently needed to manage mosquitoes. In this respect, the present study was aimed to evaluate mosquito larvicidal and pupicidal activities of 22 crude extracts of soil actinomycetes on Culex quinquefasciatus and Aedes aegypti and to identify the active molecule. Briefly, the crude ethyl acetate extract and fractions were tested at 62.5, 125, 250, and 500 ppm and 2.5, 5.0, 7.5, and 10.0 ppm concentrations on larval and pupal stages of Cx. quinquefasciatus and Ae. aegypti. The larval and pupal mortality was assessed after 24 h of treatment. Among the 22 isolates screened, Nonomuraea sp. VAS-16 exhibited significant larvicidal and pupicidal activities against the tested mosquito species. Among the 18 fractions screened, fraction-6 showed strong larvicidal and pupicidal activities with the LC50 and LC90 values of 9.1, 18.7, 9.82, and 22.85 ppm against the larvae and LC50 and LC90 values of 10.5, 23.1, 12.3, and 24.13 ppm against the pupae of Cx. quinquefasciatus and Ae. aegypti, respectively. Fascinatingly, the isolated compound 1,2-benzenedicarboxylic acid from fraction-6 at 0.5, 1.0, 1.5, and 2.0 ppm concentration recorded lower LC50 and LC90 values of 4.27, 14.90, 4.67, and 11.90 ppm against the larvae and LC50 and LC90 values of 4.58, 12.06, 5.36, and 13.07 ppm against the pupae of Cx. quinquefasciatus and Ae. aegypti, respectively. On the other hand, the compound recorded less ovicidal activity of 11.0% and 10.3% at 2 ppm against the eggs of Cx. quinquefasciatus and Ae. aegypti, respectively. The present study clearly shows that the crude extract and the compound from Nonomuraea sp. VAS-16 can be used as an effective biopesticide in integrated mosquito management program.

The CDC Bottle Bioassay serves as an inexpensive and effective way to screen field-caught mosquitoes against a wide variety of insecticidal active ingredients and commercial formulations, with the goal of detecting resistant individuals. For this study, we assessed how sucrose-water (10% w/v) feeding status impacted the response of Aedes aegypti mosquitoes to select insecticides.Starvation for 24 or 48 h decreased permethrin and malathion mean survival time by about 40%, with little difference in the two starvation times. Similar findings were also observed in a pyrethroid-resistant Puerto Rico strain challenged with permethrin, but these effects were less pronounced. To test the impact of mosquito weight, we measured weight under different 48-h nutritional conditions and found that sugar-water-fed and sugar-only-fed individuals were approximately the same weight (ANOVA, Bonferroni post-test P value0.999) and that individuals fed water only were considerably lighter than either sugar-water-fed (ANOVA, Bonferroni post-test P value = 0.034) or sugar-only-fed individuals (ANOVA, Bonferroni post-test P value = 0.027) but equal in weight to starved mosquitoes (ANOVA, Bonferroni post-test P value0.99). Of the nutritional challenges, water-only-fed mosquitoes were the most insecticide tolerant (ANOVA, Bonferroni post-test P values to all other treatments0.01).The results indicate insect nutritional status is an important experimental variable, particularly the hydration status of mosquitoes shortly before insecticide exposure. Moreover, as significant differences were observed between starved and component-fed (water, sugar, or sugar and water) mosquitoes in a pyrethroid-resistant strain, some caution is appropriate when interpreting resistance/susceptibility diagnoses with this bioassay. © 2021 Society of Chemical Industry. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Commercially available ‘smart’ trap technology has not yet been widely used to evaluate interventions against mosquitoes despite potential benefits. These benefits include the ability to capture data continuously at fine temporal scales without the human resources usually required for conventional trap deployment. Here, we used a commercially available smart trap (BG-Counter, Biogents) to assess the efficacy of an insecticide barrier treatment (BiFlex AquaMax) in reducing mosquito nuisance in a logistically challenging coastal environment in Queensland, Australia. Adoption of smart trap technology permitted us to conduct a uniquely detailed assessment of barrier treatments, ultimately allowing us to demonstrate significant reductions in mosquito collections from treated properties over all temporal scales. On average, daily mosquito collections from treated properties were reduced by 74.6% for the duration of the post-treatment period (56 d). This observation was supported by similar reductions (73.3%) in mosquito collections across all hours of the day. It was further found that underlying mosquito population dynamics were comparable across all study sites as evidenced by the high congruence in daily collection patterns among traps (Pearson r = 0.64). Despite limitations related to trap costs and replication, the results demonstrate that smart traps offer new precision tools for the assessment of barrier treatments and other mosquito control interventions.

In this study, the effect of physicochemical parameters as determinants for the abundance and distribution of Anopheles mosquitoes was examined. Physicochemical variables such as pH, temperature, DO, TDS, flow velocity, salinity and electrical conductivity were determined using standard procedures. Three communities in Ukwani LGA, Delta State were mapped out and sampled. Immature stages of Anopheles mosquitoes were collected from potential breeding sites using 350 ml dip ladles and scooping spoon. The physicochemical parameters showed that air, and water temperature, pH, and dissolved oxygen were higher in Umutu compared to the other sampled communities (Obiaruku and Umukwata). Salinity, conductivity, total dissolved solids and flow velocity were higher in Obiaruku and Umukwata compared to Umutu. Various levels of significance (p

Background There is evidence that the knockdown resistance gene (Kdr) L1014F and acetylcholinesterase-1 gene (Ace-1R) G119S mutations involved in pyrethroid and carbamate resistance in Anopheles gambiae influence malaria transmission in sub-Saharan Africa. This is likely due to changes in the behaviour, life history and vector competence and capacity of An. gambiae. In the present study, performed as part of a two-arm cluster randomized controlled trial evaluating the impact of household screening plus a novel insecticide delivery system (In2Care Eave Tubes), we investigated the distribution of insecticide target site mutations and their association with infection status in wild An. gambiae sensu lato (s.l.) populations. Methods Mosquitoes were captured in 40 villages around Bouaké by human landing catch from May 2017 to April 2019. Randomly selected samples of An. gambiae s.l. that were infected or not infected with Plasmodium sp. were identified to species and then genotyped for Kdr L1014F and Ace-1R G119S mutations using quantitative polymerase chain reaction assays. The frequencies of the two alleles were compared between Anopheles coluzzii and Anopheles gambiae and then between infected and uninfected groups for each species. Results The presence of An. gambiae (49%) and An. coluzzii (51%) was confirmed in Bouaké. Individuals of both species infected with Plasmodium parasites were found. Over the study period, the average frequency of the Kdr L1014F and Ace-1R G119S mutations did not vary significantly between study arms. However, the frequencies of the Kdr L1014F and Ace-1R G119S resistance alleles were significantly higher in An. gambiae than in An. coluzzii [odds ratio (95% confidence interval): 59.64 (30.81–131.63) for Kdr, and 2.79 (2.17–3.60) for Ace-1R]. For both species, there were no significant differences in Kdr L1014F or Ace-1R G119S genotypic and allelic frequency distributions between infected and uninfected specimens (P > 0.05). Conclusions Either alone or in combination, Kdr L1014F and Ace-1R G119S showed no significant association with Plasmodium infection in wild An. gambiae and An. coluzzii, demonstrating the similar competence of these species for Plasmodium transmission in Bouaké. Additional factors including behavioural and environmental ones that influence vector competence in natural populations, and those other than allele measurements (metabolic resistance factors) that contribute to resistance, should be considered when establishing the existence of a link between insecticide resistance and vector competence. Graphical Abstract

Urbanization processes are increasing globally. Anthropogenic alterations in the environment have profound effects on biodiversity. Decreased biodiversity due to biotic homogenization processes as a consequence of urbanization often result in increased levels of mosquito vector species and vector-borne pathogen transmission. Understanding how anthropogenic alterations in the environment will affect the abundance, richness, and composition of vector mosquito species is crucial for the implementation of effective and targeted mosquito control strategies. We hypothesized that anthropogenic alterations in the environment are responsible for increasing the abundance of mosquito species that are adapted to urban environments such as Aedesaegypti and Culexquinquefasciatus. Therefore, our objective was to survey mosquito relative abundance, richness, and community composition in Miami-Dade County, Florida, in areas with different levels of urbanization. We selected 24 areas, 16 remote areas comprised of natural and rural areas, and 8 urban areas comprised of residential and touristic areas in Miami-Dade County, Florida. Mosquitoes were collected weekly in each area for 24 h for 5 consecutive weeks from August to October 2020 using BG-Sentinel traps baited with dry ice. A total of 36,645 mosquitoes were collected, from which 34,048 were collected in the remote areas and 2,597 in the urban areas. Our results show a clear and well-defined pattern of abundance, richness, and community composition according to anthropogenic modifications in land use and land cover. The more urbanized a given area the fewer species were found and those were primary vectors of arboviruses, Ae.aegypti and Cx.quinquefasciatus.

Entomopathogenic fungi can achieve important innovative outcomes for integrated mosquito control especially of Aedes aegypti, the key vector of arboviruses to humans in the tropics and subtropics. This study sought to design and to develop a simple dissemination device to attract and to infect gravid A. aegypti adults with a granular formulation of the ascomycete Metarhizium humberi IP 46, and to validate this device in the laboratory as well as in semi-field and field conditions. Hydrogel (polyacrylamide potassium polyacrylate) was confirmed to be a suitable substitute for water used in the device that attracted gravid females under field conditions. Females laid eggs on black polyethylene terephthalate carpet fixed in the device that also proved to be a suitable substrate for a granular formulation of fungal microsclerotia and/or conidia. The plastic device (29.5 cm high) was divided into a lower closed compartment with a water reservoir and an upper, laterally open but covered compartment with continuously hydrated gel and the fungal formulation attached to the carpet. The uppermost compartment permitted free circulation of mosquito adults. The device attracted both male and female A. aegypti. The fungal formulations of IP 46 propagules tested in the device were effective against adults in laboratory, semi-field, and field settings. Findings in the laboratory, semi-field, and especially in field conditions strengthen the value and utility of this innovative device for focal applications of a mycoinsecticide against this important mosquito vector. Key points • Low-cost and simple disseminating device for focal control of Aedes aegypti. • Granulized Metarhizium humberi IP 46 and hydrogel yield extended control. • Findings in field tests strengthen benefit of the device for focal application.

The Domaine de la Palissade is a 700-ha nature reserve located at the mouth of the Rhone river in southern France. Since 2006, the tidal wetlands have been sprayed with Bacillus thuringiensis israelensis (Bti) and water level fluctuations minimized to reduce mosquito nuisance. Aerial spraying of VectoBac® 12AS (32 ITU/ha) is carried out 10 to 23 times a year, whenever Ochlerotatus caspius and Oc. detritus larvae develop, covering between 611 and 1937 cumulated hectares. Long-term trends (2000–2013) in monthly abundance of 50 bird species were compared with two nearby nature reserves that served as controls. A significant decrease in abundance of eight species (from 1958 to 941 monthly counts) was attributed to mosquito control operations and more specifically to: (1) aircraft disturbance caused by aerial spraying in a proportion of 36%, affecting mostly ducks; (2) stabilization of water levels in a proportion of 34%, affecting mostly grebes; and/or (3) reduced food resources caused by Bti effects in a proportion of 30%, affecting mostly waders. The European coot, affected negatively by all three factors, suffered the highest decline. Alternatively, the lower water levels and higher salinity resulting from the reduced exchanges with the Rhone River had a positive impact on five species, mostly gull and shorebirds (from 201 to 280 monthly observations). Overall, this study suggests a 23% significant decrease in waterbird abundance due to mosquito control, in spite of the collaboration between site managers and the operator of mosquito control to minimize negative effects on the non-target fauna.

Objective To evaluate the protective effect of house-screening (HS) on indoor Ae. aegypti infestation, abundance and arboviral infection in Merida, Mexico. Methods In 2019, we performed a cluster randomized controlled trial (6 control and 6 intervention areas: 100 households/area). Intervention clusters received permanently fixed fiberglass HS on all windows and doors. The study included two cross-sectional entomologic surveys, one baseline (dry season in May 2019) and one post-intervention (PI, rainy season between September-October 2019). The presence and number of indoor Aedes females and blood-fed females (indoor mosquito infestation) as well as arboviral infections with dengue (DENV) and Zika (ZIKV) viruses were evaluated in a subsample of 30 houses within each cluster. Results HS houses had significatively lower risk for having Aedes aegypti female mosquitoes (odds ratio [OR]=0.56, 95% C. I. 0.33-0.97, P=0.04) and blood-fed females (OR=0.53, 95% C. I. 0.28-0.97, P=0.04) than unscreened households from the control arm. Compared to control houses, HS houses had significantly lower indoor Ae. aegypti abundance (rate ratio [RR]=0.50, 95% C. I. 0.30-0.83, P=0.01), blood-fed Ae. aegypti females (RR=0.48, 95% C. I. 0.27-0.85, P=0.01) and female Ae. aegypti positive for arboviruses (OR=0.29, 95% CI 0.10-0.86, P=0.02). The estimated intervention efficacy in reducing Ae. aegypti arbovirus infection was 71%. Conclusions These results provide evidence supporting the use of HS as an effective pesticide-free method to control house infestations with Aedes aegypti and reduce the transmission of Aedes-transmitted viruses such as DENV, chikungunya (CHIKV), and ZIKV.

Background The overuse of insecticides to control insect vectors has promoted extensive insecticide resistance in mosquitoes. In this study, the functions of microRNA (miR)-279-3p and its target CYP325BB1 in the regulation of deltamethrin resistance in Culex pipiens pallens was investigated. Methods Quantitative real-time reverse transcription PCR was used to detect the expression levels of miR-279-3p and CYP325BB1. Then, the dual-luciferase reporter assay system, RNA interference, CDC bottle bioassay and Cell Counting Kit-8 (CCK-8) assay were used to explore the roles of these molecules in deltamethrin resistance both in vivo and in vitro. Results The expression patterns of miR-279-3p and CYP325BB1 were compared between deltamethrin-sensitive (DS-strain) and deltamethrin-resistant (DR-strain) mosquitoes. Luciferase activity was downregulated by miR-279-3p, the effect of which was ablated by a mutation of the putative binding site for CYP325BB1. In DR-strain mosquitoes, the expression of miR-279-3p was increased by microinjection and oral feeding of miR-279-3p agomir (mimic). CYP325BB1 mRNA levels were downregulated, which resulted in a higher mortality of the mosquitoes in miR-279-3p mimic-treated groups. In the DS-strain mosquitoes, microinjection of a miR-279-3p inhibitor decreased miR-279-3p expression, whereas the expression of CYP325BB1 was increased; the mortality of these mosquitoes decreased significantly. In addition, overexpression of pIB/V5-His-CYP325BB1 changed the sensitivity of C6/36 cells to deltamethrin in vitro. Also in DR-strain mosquitoes, downregulation of CYP325BB1 expression by microinjection of si-CYP325BB1 increased mosquito mortality in vivo. Conclusions These findings provide empirical evidence of the involvement of miRNAs in the regulation of insecticide resistance and indicate that miR-279-3p suppresses the expression of CYP325BB1, which in turn decreases deltamethrin resistance, resulting in increased mosquito mortality. Taken together, the results provide important information for use in the development of future mosquito control strategies. Graphical abstract

Pyrethroids are powerful insecticides used in the vector control program with impregnated mesh, and residual indoor sprays. However, resistance to insecticide reduces the effectiveness. The present susceptibility study carried out against the Anopheles Stephensi to monitor the sensitivity conditions of An. Stephensi vector, which raises the need to understand the state of vector resistance in the Dungarpur region of Rajasthan, India in order to better report vector-based interventions. The sensitivity study was carried out by the WHO standard method using recommended diagnostic doses of DDT, alpha-cypermethrin, permethrin, and deltamethrin. An. Stephensi showed resistance to DDT from the entire study while sensitive to alpha-cypermethrin, permethrin, and deltamethrin. The study looks at the selection and circulation of the appropriate insecticide’s molecule for a vector control program as insecticide need constant monitoring to develop effective vector control strategies such as improving insecticide by applying integrated biological and ecological methods. How to cite this article:Sharma NK, Ali MI, Moin S. Contemporary Resistance Status of Anopheles Stephensi against Insecticides in District Dungarpur, Rajasthan, India. J Commun Dis. 2021;53(3):153-158. DOI: https://doi.org/10.24321/0019.5138.202151

Mosquito-borne diseases account for human morbidity and mortality worldwide, caused by the parasites (e.g., malaria) or viruses (e.g., dengue, Zika) transmitted through bites of infected female mosquitoes. Globally, billions of people are at risk of infection, imposing significant economic and public health burdens. As such, efficient methods to monitor mosquito populations and prevent the spread of these diseases are at a premium. One proposed technique is to apply acoustic monitoring to the challenge of identifying wingbeats of individual mosquitoes. Although researchers have successfully used wingbeats to survey mosquito populations, implementation of these techniques in areas most affected by mosquito-borne diseases remains challenging. Here, methods utilizing easily accessible equipment and encouraging community-scientist participation are more likely to provide sufficient monitoring. We present a practical, community-science-based method of monitoring mosquito populations using smartphones. We applied deep-learning algorithms (TensorFlow Inception v3) to spectrogram images generated from smartphone recordings associated with six mosquito species to develop a multiclass mosquito identification system, and flag potential invasive vectors not present in our sound reference library. Though TensorFlow did not flag potential invasive species with high accuracy, it was able to identify species present in the reference library at an 85% correct identification rate, an identification rate markedly higher than similar studies employing expensive recording devices. Given that we used smartphone recordings with limited sample sizes, these results are promising. With further optimization, we propose this novel technique as a way to accurately and efficiently monitor mosquito populations in areas where doing so is most critical.

Background Harnessing insect ecology for insect control is an innovative concept that seeks to exploit, among others, insect-microbe ecological interactions for improved control of pest insects. Microbe-produced cheese odour attracts several dipterans, including host-seeking mosquitoes, but this phenomenon has not been thoroughly explored for mosquito control. Here we tested the hypothesis that attraction of mosquitoes to cheese odour can be exploited as an ecological trap for mosquito control. Results In laboratory and/or field experiments, we show that (i) each of five cheese varieties tested (Raclette, Pecorino, Brie, Gruyere, Limburger) strongly attracts female A. aegypti and Culex. pipiens; (ii) cheese infusions, or headspace odourant extracts (HOEs) of cheese infusions, significantly affect oviposition choices by mosquitoes, (iii) HOEs contain at least 13 odourants; (iv) in field settings, cheese infusions more effectively stimulate mosquito oviposition than positive bluegrass infusion controls, and also capture (by drowning) the spotted wing Drosophila, Drosophila suzukii; and (v) home-made cheese infusions modulate oviposition choices by mosquito females and affect the survivorship of their offspring larvae. Conclusion Our data show that microbial metabolites associated with cheese are attractive to mosquito females seeking hosts and oviposition sites and are likely toxic to mosquito larvae. These microbes and their metabolites could thus be co-opted for both the attract, and the kill, function of 'attract & kill' mosquito control tactics. Implementation of customizable and non-conventional nutritional media as microbe-based ecological traps presents a promising concept which exploits insect ecology for insect control. This article is protected by copyright. All rights reserved.

The decline in malaria across Africa has been largely attributed to vector control using long-lasting insecticidal nets (LLINs). However, this intervention has prompted widespread insecticide resistance (IR) and been associated with changes in mosquito behaviour that reduce their contact with LLINs. The relative importance and rate at which IR and behavioural adaptations emerge are poorly understood. We conducted surveillance of mosquito behaviour and IR at 12 sites in Burkina Faso to assess the magnitude and temporal dynamics of insecticide, biting and resting behaviours in vectors in the 2-year period following mass LLIN distribution. Insecticide resistance was present in all vector populations and increased rapidly over the study period. In contrast, no longitudinal shifts in LLIN-avoidance behaviours (earlier or outdoor biting and resting) were detected. There was a moderate but statistically significant shift in vector species composition from Anopheles coluzzii to Anopheles gambiae which coincided with a reduction in the proportion of bites preventable by LLINs; possibly driven by between-species variation in behaviour. These findings indicate that adaptations based on insecticide resistance arise and intensify more rapidly than behavioural shifts within mosquito vectors. However, longitudinal shifts in mosquito vector species composition were evident within 2 years following a mass LLIN distribution. This ecological shift was characterized by a significant increase in the exophagic species (An. gambiae) and coincided with a predicted decline in the degree of protection expected from LLINs. Although human exposure fell through the study period due to reducing vector densities and infection rates, such ecological shifts in vector species along with insecticide resistance were likely to have eroded the efficacy of LLINs. While both adaptations impact malaria control, the rapid increase of the former indicates this strategy develops more quickly in response to selection from LLINS. However, interventions targeting both resistance strategies will be needed.

Background Despite widespread use of long-lasting insecticidal nets (LLINs) and other tools, malaria caused 409,000 deaths worldwide in 2019. While indoor residual spraying (IRS) is an effective supplement, IRS is moderately expensive and logistically challenging. In endemic areas, IRS requires yearly application just before the main rainy season and potential interim reapplications. A new technology, insecticide-treated wall liner (ITWL), might overcome these challenges. Methods We conducted a 44-cluster two-arm randomized controlled trial in Muheza, Tanzania from 2015 to 2016 to evaluate the cost and efficacy of a non-pyrethroid ITWL to supplement LLINs, analyzing operational changes over three installation phases. The estimated efficacy (with 95% confidence intervals) of IRS as a supplement to LLINs came mainly from a published randomized trial in Muleba, Tanzania. We obtained financial costs of IRS from published reports and conducted a household survey of a similar IRS program near Muleba to determine household costs. The costs of ITWL were amortized over its 4-year expected lifetime and converted to 2019 US dollars using Tanzania’s GDP deflator and market exchange rates. Results Operational improvements from phases 1 to 3 raised ITWL coverage from 35.1 to 67.1% of initially targeted households while reducing economic cost from $34.18 to $30.56 per person covered. However, 90 days after installing ITWL in 5666 households, the randomized trial was terminated prematurely because cone bioassay tests showed that ITWL no longer killed mosquitoes and therefore could not prevent malaria. The ITWL cost $10.11 per person per year compared to $5.69 for IRS. With an efficacy of 57% (3–81%), IRS averted 1162 (61–1651) disability-adjusted life years (DALYs) per 100,000 population yearly. Its incremental cost-effectiveness ratio (ICER) per DALY averted was $490 (45% of Tanzania’s per capita gross national income). Conclusions These findings provide design specifications for future ITWL development and implementation. It would need to be efficacious and more effective and/or less costly than IRS, so more persons could be protected with a given budget. The durability of a previous ITWL, progress in non-pyrethroid tools, economies of scale and competition (as occurred with LLINs), strengthened community engagement, and more efficient installation and management procedures all offer promise of achieving these goals. Therefore, ITWLs merit ongoing study. First posted 2015 (NCT02533336).

To study the prevalence of anopheline mosquitoes, over 180 sites were sampled in malaria-endemic areas of Asir region, Saudi Arabia, during June 1999-April 2001. A total of 7085 larval and 754 adult female Anopheles spp. specimens were collected. Seven species were identified: An. dthali, An. rupicolus, An. sergentii, An. arabiensis, An. multicolor, An. turkhudi and An. pretoriensis. Both An. arabiensis and An. sergentii are known vectors of malaria in the region. An. dthali occurred in all sites and was the most abundant species. An. turkhudi was collected in low numbers as larvae only. An. multicolor and An. pretoriensis were recorded for the first time in Asir region. An. sergentii is a species of the northern areas of the region, whereas An. arabiensis was more prevalent in the south

Background: Aedes aegypti mosquitoes transmit dengue, zika, and chikungunya viruses, neglected diseases that are considered global health challenges. Due to the lack of antiviral drugs and vaccines for these illnesses, vector control with chemical insecticides is the principal strategy for preventing their spread. However, vector populations are becoming increasingly resistant to insecticides, and the development of other control measures is, therefore, imperative. Methods: A new insect trap (IT) was used to control Aedes aegypti. A specific light-emitting diode (LED) served as the attractant based on specific wavelength ranges (450-495, 500-550 and 570-600 nm). The IT utilized insect-attracting and killing mechanisms that included a black capture box, a suction-producing mechanism, an electric shock device and a nylon cloth device that held surviving mosquitoes, which died due to starvation. Capture assays of twenty non-feeding females inside a cage were performed in triplicate using different LED intensities. A commercial trap (ultraviolet lamp attractant and suction system) was used as a positive control. Results: Capture assays of A. aegypti with different intensities and LED combinations showed that the tricolored trap captured 100% of the females, followed by the Green LED 8 set, which captured 91%; in comparison, commercial traps captured approximately 25% of the insects. Although there were no significant differences between the experimental groups, the tricolored trap probably will capture more mosquito females considering the vision variation in individual females. Conclusion: We herein present a green technology-based IT that is effective, safe and successful for reducing mosquito populations, thereby preventing mosquito-borne disease spread.

Nanotechnology is an emerging technology and day to day expanding its roots of knowledge to various branches of Science and fulfilling human conveniences. To manage vector populations, new tools have been emerging through nanotechnology. Nanoparticles possess peculiar toxicity mechanisms due to surface volume ratio, and this may actively contribute to their excellent larvicidal potential against Aedes aegypti mosquito. Dengue is a mosquito borne disease and making major public health issue worldwide. Aedes (Stegomyia) aegypti (Linnaeus, 1762) prefers to bread in artificial containers, and anti-larval measures with Ximenia americana L. (Olacaceae) leaf mediated silver nanoparticles (AgNPs) proves to be a potential substitute for the existing organophosphorus insecticides like temephos, malathion and fenthion etc., for mosquito control programme. Larvae were exposed to varying concentrations of plant extracts and synthesized silver nanoparticles for 24 hours. From the results, it was found that plant extracts showed moderate larvicidal effects (LC50 at 179.87 and LC90 at 376.77 ppm) but, the synthesized silver nanoparticles had found to be toxic to larvae at LC50 (0.63 ppm) and LC90 (1.20 ppm). This research highlighted that, the Ximenia americana leaf mediated AgNPs are an efficient and eco-friendly agents against Ae. aegypti mosquito, though the laboratory studies have shown the promising results, yet their efficacy in the field is to be tested for effective mosquito larval control.

Culex pipiens sensu lato has been documented as West Nile virus (WNV) vector in southeastern Romania. Bucharest, the densely populated capital city of Romania, and the surrounding Ilfov county are WNV hotspots. In this area, the morphologically indistinguishable biotypes of Cx. pipiens, namely pipiens and molestus, are usually differentiated by their behavioral and physiological traits. Their involvement in WNV transmission, as suggested by entomological investigations, was not previously documented for each biotype. We used a Real-Time PCR assay based on CQ11 microsatellite to identify the Cx. pipiens biotypes and their hybrids collected in various habitats in the Bucharest metropolitan area. A sympatric distribution of both biotypes was observed, with a preference of green areas for pipiens, and human settings and animal farmlands for molestus. In the latter habitats, pipiens and molestus were found in mixed aboveground populations. A low number of hybrids was found suggesting existence of reproductive isolation. In subway tunnels molestus was dominant with a higher number of hybrids recorded than aboveground. Blood-engorged mosquitoes were identified to biotype and the blood meal source identified by DNA barcoding. Overall, Cx. pipiens s.l. fed mainly on birds, commonly on house sparrows, collared doves, and blackbirds, which are potential WNV-amplifying hosts. The preference for avian hosts was expressed strongest by pipiens biotype, while molestus was substantially less specific, feeding on avian and mammal hosts with similar frequency, with humans representing 20% of the hosts. Hybrids had a host choice closer to that of molestus. These findings highlight the role of pipiens biotype as enzootic/epizootic vector, and specifically show molestus as the bridge vector for WNV. The pipiens and molestus biotypes show important differences in habitat preferences, including oviposition; these findings demonstrate that targeted mosquito control to limit WNV transmission may be possible.

The scale up of indoor residual spraying (IRS) and insecticide treated nets have contributed significantly to global reductions in malaria prevalence over the last two decades. However, widespread pyrethroid resistance has necessitated the use of new and more expensive insecticides for IRS. Partial IRS with pirimiphos-methyl in experimental huts and houses in a village-wide trial was evaluated against Anopheles gambiae s.l. in northern Ghana. Four different scenarios in which either only the top or bottom half of the walls of experimental huts were sprayed, with or without also spraying the ceiling were compared. Mortality of An. gambiae s.l. on partially sprayed walls was compared with the standard procedures in which all walls and ceiling surfaces are sprayed. A small-scale trial was then conducted to assess the effectiveness, feasibility, and cost of spraying only the upper walls and ceiling as compared to full IRS and no spraying in northern Ghana. Human landing catches were conducted to estimate entomological indices and determine the effectiveness of partial IRS. An established transmission dynamics model was parameterized by an analysis of the experimental hut data and used to predict the epidemiological impact and cost effectiveness of partial IRS for malaria control in northern Ghana. In the experimental huts, partial IRS of the top (IRR 0.89, p = 0.13) or bottom (IRR 0.90, p = 0.15) half of walls and the ceiling was not significantly less effective than full IRS in terms of mosquito mortality. In the village trial, the annual entomological inoculation rate was higher for the unsprayed control (217 infective bites/person/year (ib/p/yr)) compared with the fully and partially sprayed sites, with 28 and 38 ib/p/yr, respectively. The transmission model predicts that the efficacy of partial IRS against all-age prevalence of malaria after six months would be broadly equivalent to a full IRS campaign in which 40% reduction is expected relative to no spray campaign. At scale, partial IRS in northern Ghana would have resulted in a 33% cost savings ($496,426) that would enable spraying of 36,000 additional rooms. These findings suggest that partial IRS is an effective, feasible, and cost saving approach to IRS that could be adopted to sustain and expand implementation of this key malaria control intervention.

Plant secondary metabolites represent the most efficient and convenient method to control and overcome environmental pollution and insecticidal resistance. This study explored the mosquitocidal activity of the combined extract of seven plants, (HF7) extracted using a Soxhlet extractor against Culex pipiens under laboratory conditions. Exposure of the 3rd instars of Cx. pipiens to HF7 hexane extract resulted in LC50:114.5 μg/mL and LC90:117.0 μg/mL values after 24 h. The ovicidal activities of hexane extract against Cx. pipiens eggs were 21.6%, 48.3%, and 71.6% at 187.5, 93.7, and 46.88 μg/mL, respectively. HF7-treated larvae showed the formation of irregular blebbing of epithelial cells toward the lumen and sloughing into the gut lumen. HF7 extract resulted in 100% adulticidal mortality at the concentration of 3.7 mg/test tube after 30 min of exposure. The IC50 of HF7 extract was 97.03 µg/ml against larvae, at which nuclear and morphological changes were observed. The spectroscopy spectrum of HF7 hexane extract disclosed the presence of 57 different secondary metabolites, among which the dominant compound was eugenol (32.3%). HF7 hexane extract could serve as a botanical insecticide for controlling Cx. pipiens and potentially other mosquito species.

The world has experienced perceptible climate change for the past 100 years. Global warming enhances the rapid spread of mosquito-borne diseases resulting in unknown consequences in the future. The global economic development, increased urbanization, and climate change have significantly increased the mosquito-borne disease transmission pattern and dynamics. In India, mosquito-borne diseases have been a core public issue for decades. Hence, mosquito control is primordial for preventing the transmission of malaria, lymphatic filariasis, dengue fever, Yellow fever, Zika virus infection, West Nile fever, and chikungunya virus infection in the human population. The mosquito control strategies based on ecology have received much more attention during the 1960s, as chemical pesticides induce negative impacts on human health and the ecosystem. Most of the current approaches in mosquito control have several limitations related to the development of insecticide resistance, lack of long-term sustainability, and negative impacts on the ecosystem and the environment. This review offers invaluable insights into severe mosquito-borne diseases, various vector control strategies, and the influence of climate change in mosquito-borne disease transmission.

Mosquitoes are well known for being vectors of many pathogens causing diseases. The widespread use of synthetic insecticides in mosquito control has resulted in the growth of resistance to pesticides and the degradation of the ecosystem. Therefore, plants have become alternative sources of mosquito control in recent years. In the current research five plants viz. eucalyptus, neem, mint, niazbow, ginger and canola were evaluated against Aedes aegypti and A. albopictus mosquitoes. The toxicity of the crude extracts of all the plants against the third stage larvae of Aedes spp. gave significant results. The study showed a very substantial difference in the length of the repellents and the bite safety between the repellents and the control. Canola was less effective as compared to all other test plants. All the essential oils tested offered protection for a minimum period of > 33 minutes and may therefore be included in the standard list of repellents of Aedes species. Neem oil repellent had the best repellence against both Aedes mosquito species with defence times of (246±15.78) and (256±14.87) minutes respectively against A. egypti and A. albopictus as well. The defence time against A. aegypti was (14.34±0.00) and (19.24±0.00) minutes for the canola oil used as power against A. aegypti as well as A. albopictus . Ginger oil offered the least defence 35.76±4.99 and 33.76±4.99 minutes against A. aegypti and A. albopictus respectively. These two oils were better than other oil formulations and were statistically significant from each other. It is concluded that these plants can be used as alternatives for the management of mosquitos

BACKGROUND Exploiting indoor-resting mosquitoes' innate behavioral responses to commonly used insecticide is crucial in vector control programs. Indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) treated with pyrethroids have become widely used for controlling dengue fever vectors. The present study tested the effects of piperonyl butoxide (PBO) synergism and cuticular thickening on the contact irritancy response of field A. aegypti (Diptera: Culicidae) to deltamethrin in Taiwan and Thailand. RESULTS The escape response of field mosquitoes treated with PBO was significantly elicited, with an escape percentage increase between 2- and 10-fold. In addition, the escape time was significantly lower in PBO-pretreated mosquitoes compared with field mosquitoes treated with deltamethrin alone. PBO-pretreated mosquitoes from seven out of 11 field strains exhibited a knockdown percentage of 11.23-54.91%, significantly higher than that of mosquitoes in corresponding strains treated with deltamethrin only. The Annan, Zhongxi, Sanmin, and North strains exhibited weak knockdown responses (≤3.75%). The mortality of PBO-pretreated field mosquitoes increased 2- to 75-fold compared with those treated with deltamethrin alone (mortality: 0-6.70%). Furthermore, the effect of cuticular thickness on the escape response of field mosquitoes was significant, that is, the escape response marginally increased inversely to cuticular thickness. By contrast, cuticular thickness was not significantly associated with knockdown or mortality percentage. CONCLUSION Irritant behavior in mosquitoes was significantly elicited by PBO synergism. PBO incorporating deltamethrin IRS or LLINs may be effective for controlling dengue fever vectors. © 2021 Society of Chemical Industry.

Larvicides that contain spinosad, a bacterial metabolite, are used to control mosquitoes in diverse aquatic habitats. These same habitats are home to other invertebrates, including Crustacea—fairy shrimp, isopods, and amphipods—and mollusks—fingernail clams and freshwater snails. A double-blind study evaluated the effects of Natular® G, a granular treatment containing spinosad, on spring Aedes spp. and nontarget invertebrates in vernal wetlands. Within 14 days after application, Natular G controlled larvae of spring Aedes by 53–84%, depending on species, but had no significant effects on numbers of fairy shrimp, fingernail clams, or freshwater snails. A second double-blind study evaluated effects on Coquillettidia perturbans and nontarget isopods and amphipods in cattail marshes. Treatment reduced emergence of Cq. perturbans by 25% but did not change numbers of isopods or amphipods. The 2 experiments indicate Natular G could be effective against spring Aedes in vernal wetlands, less so against Cq. perturbans in cattail marshes, and yet pose minimal risk to crustaceans and mollusks in either vernal wetlands or cattail marshes.

Mosquito surveillance is the cornerstone for determining abundance, species diversity, pathogen infection rates, and temporal and spatial distribution of different life stages in an area. Various methods are available for assessing adult mosquito populations, including mechanical trap devices using different forms of attractant cues (chemical and visual) to lure mosquitoes to the trap. So-called “light traps” use various electromagnetic wavelengths to produce a variety of visible spectral colors to attract adult mosquitoes. However, this type of trapping technology has not been widely used in Thailand. This study compared the efficacy of 4 light-emitting diodes (LEDs) (blue, green, yellow, and red) and 2 fluorescent (ultraviolet [UV] and white) lights for collecting mosquitoes in urban Bangkok. Using a Latin square experimental design, 6 light traps equipped with different lights were rotated between 6 trap site locations within the Kasetsart University (KU) campus. Each location received 6 replicate collections (6 consecutive trap-nights represented 1 replicate) over 36 collection nights for a total of 216 trap-nights. Traps were operated simultaneously (1800 to 0600 h), with captured mosquitoes removed at 3-h intervals. In total, 2,387 mosquitoes consisting of 11 species across 5 genera (Aedes, Anopheles, Armigeres, Culex, and Mansonia) were captured. Collectively, Culex species represented the predominant group sampled (2,252; 94.4%). The UV light source captured 1,544 (64.7%) of the total mosquitoes collected, followed by white 389 (16.3%), with the 4 LED sources collecting between 6.8% (blue) and 1.9% (yellow). Traps equipped with UV light were clearly the most effective for capturing nocturnally active mosquito species on the KU campus.

Background Dengue is a significant public health issue that is caused by Aedes spp. mosquitoes. The current vector control methods are unable to effectively reduce Aedes populations and thus fail to decrease dengue transmission. Hence, there is an urgent need for new tools and strategies to reduce dengue transmission in a wide range of settings. In this study, the Mosquito Home System (MHS) and Mosquito Home Aqua (MHAQ) formulations were assessed as commercial autodissemination traps in laboratory and small-scale field trials. Method Multiple series of laboratory and small-scale field trials were performed to assess the efficacy of MHS and MHAQ exposed to Ae. aegypti. In the laboratory trials, various parameters such as fecundity, fertility, wing size, oviposition preferences, residual effects, and MHAQ transference to other containers through controlled experiments were tested. For small-scale field trials, the efficacy of the MHS and MHAQ approaches was determined to ascertain whether wild mosquitoes could transfer the MHAQ formulation from MHS stations to ovitraps. Results The data revealed that Ae. aegypti was highly susceptible to low concentrations of MHAQ formulations and had a residual effect of up to 3 months, with MHAQ exposure affecting fecundity, fertility, and mosquito wing size. In the oviposition studies, gravid females strongly preferred the hay infusion compared to tap water and MHAQ during egg-laying in the laboratory. Nevertheless, the use of commercial MHAQ by MHS was highly attractive in field settings compared to conventional ovitraps among local Aedes spp. mosquitoes. In addition, MHAQ horizontal transfer activities in the laboratory and small-scale field trials were demonstrated through larval bioassays. These findings demonstrated the potential of MHAQ to be transferred to new containers in each study site. Conclusion This study provided proof of principle for the autodissemination of MHAQ. Through further refinement, this technique and device could become an effective oviposition trap and offer an alternative preventive tool for vector control management. Graphical abstract

Zingiber cassumunar is an important plant used in traditional medicine and as a natural mosquito repellent. However, the compounds responsible for the repellent activity of the plant are still unknown. The aim of the study is to identify the components of Z. cassumunar essential oil that show repellent activity against Aedes albopictus. We also evaluated the larvicidal and adulticidal activities of Z. cassumunar essential oil against Ae. albopictus. In-cage mosquito repellent experiments showed that Z. cassumunar essential oil possessed moderate repellent activity with a minimum effective dose (MED) of 0.16 ± 0.01 mg/cm2, compared to reference standard N,N-diethyl-3-methylbenzamide (DEET, 0.03 ± 0.01 mg/cm2). Bioassay-guided fractionation identified the major active compound of Z. cassumunar essential oil as (−)-terpinen-4-ol (1) (MED: 0.19 ± 0 mg/cm2). We also found that Z. cassumunar essential oil showed moderate larvicidal activity against first instar larvae of Ae. albopictus with a LC50 (50% lethal concentration) of 44.9 μg/L after 24 h. Fumigation bioassays showed that Z. cassumunar essential oil exhibits moderate adulticidal activity against Ae. albopictus with a LC50 of 5.44%, while (−)-terpinen-4-ol showed significant adulticidal activity with a LC50 of 2.10% after 24 h. This study verifies that the Z. cassumunar essential oil has mosquito repellent activity, and that (−)-terpinen-4-ol is mainly responsible for this activity. Furthermore, this study provides scientific support for the folk usage of Z. cassumunar essential oil as mosquito repellent and indicates that Z. cassumunar essential oil and (−)-terpinen-4-ol can be used as plant-derived repellents and insecticides for mosquito control.

The Aedes aegypti index in the buffer area of the Class 1 Surabaya Port Health Office was in accordance with the Standard Operating Procedures (SOP) as stated in the Regulation of the Indonesian Ministry of Health Number 431 of 2007 (431/MENKES/SK/IV/2007) on Technical Guidelines for Control of Environmental Health Risks in Ports/Airports/Cross-Border in the Context of Health Quarantine. The Port Health Office has responsibilities to control environmental risks, one of which was the Aedes aegypti mosquitos in the borders. This study was descriptive observational and aimed to analyze the managerial components in Aedes aegypti mosquito control in the buffer area ofthe Class 1 Surabaya Port Health Office in Surabaya. The research variables (factors that determine control activities) were manpower, money, methods, materials, markets, machines, and information. The research subjects were two officers at Class 1 Surabaya Port Health Office and five cadres who monitored larva. Data were analyzed descriptively. The results explained that manpower, money, materials, market, technology, and information were all in accordance with the SOP of the Surabaya Port Health Office. However, the larva survey method did not comply with the SOP as officers still used the visual method. It was concluded that managerial components in Aedes aegypti control by Class 1 Surabaya Port Health Office followed the SOP except in their larva survey method. The researchers recommended carrying out a larva survey method by taking 1 larva from each container (single larva) at a time. Keywords: Aedes aegypti, control vector, managerial components.

Background Aedes vigilax is one of the most significant arbovirus vector and pest species in Australia’s coastal regions. Occurring in multiple countries, this mosquito species occurs as a species complex which has been separated into three clades with two detected in Australia. Until recently, Ae. vigilax has largely been absent from Victoria, only occasionally caught over the years, with no reported detections from 2010 to 2016. Complicating the detection of Ae. vigilax is the shared sympatric distribution to the morphologically similar Ae. camptorhynchus, which can exceed 10,000 mosquitoes in a single trap night in Victoria. Currently, there are no molecular assays available for the detection of Ae. vigilax. We aim to develop a quantitative PCR (qPCR) for the detection of Ae. vigilax, with the specificity and sensitivity of this assay assessed as well as a method to process whole mosquito traps. Methods Trapping was performed during the 2017–2020 mosquito season in Victoria in two coastal areas across these 3 consecutive years. A qPCR assay was designed to allow rapid identification of Ae. vigilax as well as a whole mosquito trap homogenizing and processing methodology. Phylogenetic analysis was performed to determine which clade Ae. vigilax from Victoria was closest to. Results Aedes vigilax was successfully detected each year across two coastal areas of Victoria, confirming the presence of this species. The qPCR assay was proven to be sensitive and specific to Ae. vigilax, with trap sizes up to 1000 mosquitoes showing no inhibition in detection sensitivity. Phylogenetic analysis revealed that Ae. vigilax from Victoria is associated with clade III, showing high sequence similarity to those previously collected in New South Wales, Queensland and Western Australia. Conclusions Aedes vigilax is a significant vector species that shares an overlapping distribution to the morphologically similar Ae. camptorhynchus, making detection difficult. Here, we have outlined the implementation of a specific and sensitive molecular screening assay coupled with a method to process samples for detection of Ae. vigilax in collections with large numbers of non-target species. Graphical abstract

This study assessed the perception of pregnant women on indoor residual spraying (IRS), documented acceptability, and factors that significantly dictate willingness to use IRS among the pregnant women attending antenatal clinic in Ibadan Nigeria. A structured questionnaire was used to obtain relevant information from 500 pregnant women. Descriptive and principal component analysis (PCA) were done at 5% level of significance. Majority of the pregnant women had between good and fair knowledge of IRS. Less than 70% of the respondents were willing to allow IRS in their homes. Our PCA revealed that major factors responsible for acceptance and willingness to use IRS were associated with perceived benefits, advantages, and disadvantages of IRS rather than overall knowledge of IRS among the respondents. The analysis revealed that these factors were responsible for at least 80% of the reasons for a pregnant woman to willingly accept IRS or not. The factors that positively influenced willingness to use IRS include its benefit in controlling mosquitoes and other insects, reducing malaria incidence, and prolonged effects of IRS which is an added advantage over continuous purchase of aerosols. One major factor that may negatively affect the acceptance of IRS is the fact that you may have to pack out of the house and wait for more than 3 d before entering. This current study has identified some specific factors that seem to promote and/or reduce willingness to accept IRS as a malaria control intervention among pregnant women in South Western Nigeria.

Background Insecticide resistance has become a widespread problem causing a decline in the effectiveness of vector control tools in sub-Saharan Africa. In this situation, ongoing monitoring of vector susceptibility to insecticides is encouraged by the WHO to guide national malaria control programmes. Our study was conducted from April to November 2018 in Tchonka (Sud-Kivu, Democratic Republic of the Congo) and reported primary data on the resistance status of Anopheles funestus and Anopheles gambiae. Methods Insecticide susceptibility bioassays were performed on wild populations of A. funestus and A. gambiae using WHO insecticide-impregnated papers at discriminating concentration. In addition, PCR was performed to identify mosquito species and to detect kdr and ace-1R mutations involved in insecticide resistance. Results Bioassay results show resistance to all tested insecticides except pirimiphos-methyl, propoxur, fenitrothion and malathion with a mortality rate ranging from 95.48 to 99.86%. The addition of piperonyl butoxide (PBO) increased the susceptibility of vectors to deltamethrin and alpha-cypermethrin by exhibiting a mortality ranging from 91.50 to 95.86%. The kdr mutation was detected at high frequencies (approximately 0.98) within A. gambiae while ace-1R was not detected. Conclusions This study provides useful data on the insecticide resistance profiles of malaria vector populations to better manage vector control. Our results highlight that, despite the high level of resistance, organophosphorus compounds and pyrethroids + PBO remain effective against the vectors.

Livebearers in the family Poeciliidae are some of the most widely introduced fishes. Native poeciliid translocations within the U.S. are mostly due to deliberate stocking for mosquito control. Introductions of exotic poeciliids, those not native to the U.S., are more likely to be due to release from aquaria or escape from farms. Many of these non-natives originate from warm climate regions, contrasting with the relatively cold climates in the U.S. Thus, thermal springs may increase the possible range of these species. Our primary objective was to examine the importance of climate and thermal springs in affecting the distribution of translocated and non-native poeciliids in the U.S. This objective was addressed using a national database of poeciliid introductions. Records were dominated by a handful of states and most introductions led to established populations. While translocated mosquitofish were found across many states and climates, non-natives were found almost exclusively in warm climate states and territories (e.g., Florida, Hawaii, Puerto Rico), especially where air temperatures remained above freezing. Outside warm climate states, 46% of established non-native populations were located at thermal spring sources. These results indicate that thermal springs extend the distribution of non-natives, but were relatively unimportant for translocated poeciliids.

Here, we report the first population genetic study to examine the impact of indoor residual spraying (IRS) on Plasmodium falciparum in humans. This study was conducted in an area of high seasonal malaria transmission in Bongo District, Ghana. IRS was implemented during the dry season (November–May) in three consecutive years between 2013 and 2015 to reduce transmission and attempt to bottleneck the parasite population in humans towards lower diversity with greater linkage disequilibrium. The study was done against a background of widespread use of long‐lasting insecticidal nets, typical for contemporary malaria control in West Africa. Microsatellite genotyping with 10 loci was used to construct 392 P. falciparum multilocus infection haplotypes collected from two age‐stratified cross‐sectional surveys at the end of the wet seasons pre‐ and post‐IRS. Three‐rounds of IRS, under operational conditions, led to a >90% reduction in transmission intensity and a 35.7% reduction in the P. falciparum prevalence (p

Culex quinquefasciatus, a member of the Culex pipiens complex, is widespread in Saudi Arabia and other parts of the world. It is a vector for lymphatic filariasis, Rift Valley fever, and West Nile virus. Studies have shown the deleterious effect of RNA interference (RNAi)-mediated knockdown of various lethal genes in model and agricultural pest insects. RNAi was proposed as a tool for mosquito control with a focus on Aedes aegypti and Anopheles gambiae. In this study, we examined the effect of RNAi of selected target genes on both larval mortality and adult emergence of Cx. quinquefasciatus through two delivery methods: soaking and nanoparticles. Ten candidate genes were selected for RNAi based on their known lethal effect in other insects. Disruption of three genes, chitin synthase-1, inhibitor of apoptosis 1, and vacuolar adenosine triphosphatase, resulted in the highest mortality among the selected genes using the two treatment methods. Silencing the other seven genes resulted in a medium to low mortality in both assays. These three genes are also active against a wide range of insects and could be used for RNAi-based mosquito control in the future.

BackgroundDengue suppression often relies on control of the mosquito vector,Aedes aegypti, through applications of insecticides of which the pyrethroid group has played a dominant role. Insecticide resistance is prevalent inAe.aegyptiaround the world, and the resulting reduction of insecticide efficacy is likely to exacerbate the impact of dengue. Dengue has been a public health problem in Saudi Arabia, particularly in Jeddah, since its discovery there in the 1990s, and insecticide use for vector control is widespread throughout the city. An alternative approach to insecticide use, based on blocking dengue transmission in mosquitoes by the endosymbiontWolbachia, is being trialed in Jeddah following the success of this approach in Australia and Malaysia. Knowledge of insecticide resistance status of mosquito populations in Jeddah is a prerequisite for establishing aWolbachia-based dengue control program as releases ofWolbachiamosquitoes succeed when resistance status of the release population is similar to that of the wild population.MethodsWHO resistance bioassays of mosquitoes with deltamethrin, permethrin and DDT were used in conjunction with TaqMan®SNP Genotyping Assays to characterize mutation profiles ofAe.aegypti.ResultsScreening of the voltage-sensitive sodium channel (Vssc), the pyrethroid target site, revealed mutations at codons 989, 1016 and 1534 inAe.aegyptifrom two districts of Jeddah. The triple mutant homozygote (1016G/1534C/989P) was confirmed from Al Safa and Al Rawabi. Bioassays with pyrethroids (Type I and II) and DDT showed that mosquitoes were resistant to each of these compounds based on WHO definitions. An association betweenVssc mutations and resistance was established for the Type II pyrethroid, deltamethrin, with one genotype (989P/1016G/1534F) conferring a survival advantage over two others (989S/1016V/1534C and the triple heterozygote). An indication of synergism of Type I pyrethroid activity with piperonyl butoxide suggests that detoxification by cytochrome P450s accounts for some of the pyrethroid resistance response inAe.aegyptipopulations from Jeddah.ConclusionsThe results provide a baseline for monitoring and management of resistance as well as knowledge ofVssc genotype frequencies required inWolbachiarelease populations to ensure homogeneity with the target field population.Vssc mutation haplotypes observed show some similarity with those fromAe.aegyptiin southeast Asia and the Indo-Pacific, but the presence of the triple mutant haplotype in three genotypes indicates that the species in this region may have a unique population history.Graphical Abstract

Mosquito control has been facing backlashes due to the emergence of resistant varieties against synthetic insecticides. The bioactivity of five plant extracts viz., Poncirus trifoliate, Murraya paniculata, Citrus bergamia, Aegle marmelos and Limonia acidissima was studied against the filarial vector of Culex quinquefasciatus Say, 1823. Larvicidal assays were conducted under laboratory condition to evaluate the 24 h LC50 and LC90 of the selected plants against 3rd instar larvae of Cx. quinquefasciatus. The lethal concentration (LC50 and LC90) values ranged from 76.26 to 208.32 mg/L and 191.85 to 477.16 mg/L, respectively. The result of larvicidal test suggests that the larvicidal activity of the L. acidissima and P. trifoliate extracts were highly influenced. Test results showed that the flavonoid compounds exhibited larvicidal activity against 3rd instar Cx. quinquefasciatus mosquitoes. Percent reduction was recorded with an LC50 concentration of L. acidissima and P. trifoliate. A field study was carried out to evaluate larvicidal activity on 24 h, 48 h and 78 h period and percentage of larval and pupal reduction due to L. acidissima and P. trifoliate extracts in the unused cement tank and mini water pool in Puthanampatti, Tiruchirappalli district. The field tested plant extracts proved to have various activities against different life stages of Cx. spp. Therefore, flavonoid compounds from L. acidissima and P. trifoliate plant can be a potential candidate for use in the development of commercial mosquito larvicidal products that may be an alternative to conventional synthetic chemicals, particularly in integrated vector control applications.

CRISPR-based gene-drives targeting the gene doublesex in the malaria vector Anopheles gambiae effectively suppressed the reproductive capability of mosquito populations reared in small laboratory cages. To bridge the gap between laboratory and the field, this gene-drive technology must be challenged with vector ecology. Here we report the suppressive activity of the gene-drive in age-structured An. gambiae populations in large indoor cages that permit complex feeding and reproductive behaviours. The gene-drive element spreads rapidly through the populations, fully supresses the population within one year and without selecting for resistance to the gene drive. Approximate Bayesian computation allowed retrospective inference of life-history parameters from the large cages and a more accurate prediction of gene-drive behaviour under more ecologically-relevant settings. Generating data to bridge laboratory and field studies for invasive technologies is challenging. Our study represents a paradigm for the stepwise and sound development of vector control tools based on gene-drive., Experimental analysis of gene drive population dynamics has mostly been limited to small cage trials. Here the authors, to fill the gap between lab based studies and field studies, use large indoor cages and see population suppression without the emergence of resistant alleles