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Culex species, such as Culex quinquefasciatus and Culex nigripalpus display a range of feeding habits and act as vectors for pathogens that can cause diseases in both humans and animals. Understanding their feeding habits is pivotal for enhancing disease prevention strategies. The present study introduces the application of two multiplex real‐time PCR (qPCR) followed by high‐resolution melting (HRM) as a cost‐effective and time‐efficient alternative. This investigation involved the development of two multiplex qPCR‐HRM: assay 1 detects human, dog and chicken, while assay 2 detects cat, cattle and horse in Culex sp. engorged female mosquitoes. The qPCR‐HRM reactions showed a detection limit of one copy of genomic DNA when performed as single and multiplex qPCR‐HRM. The reaction efficiencies were 97.96% for human, 100.60% for dog, 99.03% for chicken, 99.92% for feline, 99.18% for cattle and 97.68% for horse. The qPCR‐HRM method, employing multiplex 1 and 2, was applied to field‐collected mosquitoes and demonstrated the ability to detect DNA from multiple blood sources within a single sample. By analysing both multiplexes, it was possible to identify up to five distinct blood sources in Cx. quinquefasciatus and Cx. nigripalpus, and up to two sources in Culex coronatus. Sequencing corroborated the qPCR‐HRM results, confirming the presence of DNA from one to four different blood sources with 100% accuracy. The development of these molecular methods may contribute for identification of blood‐feeding patterns in mosquitoes. It contributes to studies on the dissemination and transmission of pathogens among various animals and humans, thereby bridging the gap between epidemiology and vector monitoring. [ABSTRACT FROM AUTHOR]

In this study, veratrylidenehydrazide was isolated from Wedelia biflora, and compounds (1a, 2a, and 3a–j) were synthesised to evaluate their larvicidal and antifeedant activities. Veratrylidenehydrazide 1a was verified using GC‐MS. The veratrylidenehydrazide analogues 2a and 3a–j were synthesised via a condensation method with yield range 71%–92%. The compounds (1a, 2a, and 3a–j) were synthesised and characterised through FT–IR, 1H NMR, 13C NMR, mass spectrometry, and elemental analysis. Veratrylidenehydrazide 1a was verified using GC‐MS analysis. Natural veratrylidenehydrazide compound 1a and the synthesised veratrylidenehydrazide analogues (2a, 3a–j) were screened for larvicidal activity against Culex quinquefasciatus. The larvicidal activity of compound 3g was found to be highly active, while low toxicity was observed against Oreochromis mossambicus nontarget aquatic species compared to natural veratrylidenehydrazide. Compound 3g exhibited a higher binding affinity (−8.8 kcal/mol) compared to standard of temephos (−4.5 kcal/mol), equipotential binding affinity against permethrin (−9.1 kcal/mol), and diflubenzuron (−8.5 kcal/mol). Lead molecules have larvicidal properties, and their use as insecticides makes them important. [ABSTRACT FROM AUTHOR]

Culex quinquefasciatus Say 1823 (Diptera: Culicidae), a vector of lymphatic filariasis and various arboviruses, is the most abundant mosquito owing to its breeding capacity in polluted stagnant water. Alphacypermethrin (C22H19Cl2NO3) is a highly effective synthetic pyrethroid insecticide, used for the management of agricultural pests as well as vector control. In this study, two strains of Cx. quinquefasciatus were reared in the laboratory with the same genetic background, one strain was selected against alphacypermethrin (AS) and another strain was devoid of insecticide treatment and reared as susceptible (S) for 15 generations. It was observed that the sub-lethal exposure to insecticide led to a low fecundity rate, less hatchability, longer larval developmental time, low pupation rate, and less emergence rate but no significant differences in sex ratio. AS strain showed 37.4-fold, 2.85-fold, fivefold, and 8.6-fold higher activity in comparison to S strain in monooxygenases, alphaesterases, betaesterases, and glutathione-S-transferases activity respectively, implying the role of detoxifying enzyme in metabolic resistance development. This study was conducted to elucidate the sub-lethal effects of insecticide on the life history traits of the exposed strain and their association with metabolic resistance which would ultimately help to design vector control programs against insecticide resistance. [ABSTRACT FROM AUTHOR]

Background: Mosquitoes serve as vectors for numerous pathogens, posing significant health risks to humans and animals. Understanding the complex interactions within mosquito microbiota is crucial for deciphering vector-pathogen dynamics and developing effective disease management strategies. Here, we investigated the nested patterns of Wolbachia endosymbionts and Escherichia-Shigella within the microbiota of laboratory-reared Culex pipiens f. molestus and Culex quinquefasciatus mosquitoes. We hypothesized that Wolbachia would exhibit a structured pattern reflective of its co-evolved relationship with both mosquito species, while Escherichia-Shigella would display a more dynamic pattern influenced by environmental factors. Results: Our analysis revealed different microbial compositions between the two mosquito species, although some microorganisms were common to both. Network analysis revealed distinct community structures and interaction patterns for these bacteria in the microbiota of each mosquito species. Escherichia-Shigella appeared prominently within major network modules in both mosquito species, particularly in module P4 of Cx. pipiens f. molestus, interacting with 93 nodes, and in module Q3 of Cx. quinquefasciatus, interacting with 161 nodes, sharing 55 nodes across both species. On the other hand, Wolbachia appeared in disparate modules: module P3 in Cx. pipiens f. molestus and a distinct module with a single additional taxon in Cx. quinquefasciatus, showing species-specific interactions and no shared taxa. Through computer simulations, we evaluated how the removal of Wolbachia or Escherichia-Shigella affects network robustness. In Cx. pipiens f. molestus, removal of Wolbachia led to a decrease in network connectivity, while Escherichia-Shigella removal had a minimal impact. Conversely, in Cx. quinquefasciatus, removal of Escherichia-Shigella resulted in decreased network stability, whereas Wolbachia removal had minimal effect. Conclusions: Contrary to our hypothesis, the findings indicate that Wolbachia displays a more dynamic pattern of associations within the microbiota of Culex pipiens f. molestus and Culex quinquefasciatus mosquitoes, than Escherichia-Shigella. The differential effects on network robustness upon Wolbachia or Escherichia-Shigella removal suggest that these bacteria play distinct roles in maintaining community stability within the microbiota of the two mosquito species. [ABSTRACT FROM AUTHOR]

Background: Mosquitoes in nature may acquire multiple bloodmeals (BMs) over the course of their lifetime; however, incorporation of frequent feeding behavior in laboratory vector competence studies is rarely done. We have previously shown that acquisition of a second non-infectious BM can enhance early dissemination of Zika virus (ZIKV), dengue virus, and chikungunya virus in Aedes aegypti and ZIKV in Aedes albopictus mosquitoes, yet it is unknown if other taxonomically-diverse virus-vector pairings show a similar trend under a sequential feeding regimen. Methods: To test this, we evaluated the impact of a second noninfectious BM on the vector competence of Aedes aegypti and Anopheles quadrimaculatus for Mayaro virus, Culex quinquefasciatus for West Nile virus, Aedes triseriatus for La Crosse virus, and Aedes aegypti for Oropouche virus (OROV). Female mosquitoes were fed BMs containing these viruses and half of them were given a second noninfectious BM at 3 or 4-days post infection. Mosquitoes were harvested at various time points and assayed for virus infection in bodies and disseminated infection in legs by performing reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assays. Results: We found that a second noninfectious BM had no impact on midgut infection rates but increased virus dissemination for all but one of the virus-vector pairings- Ae. aegypti and OROV. Unlike the other arboviruses under consideration, which are strictly mosquito-borne, biting midges (Culicoides spp.) serve as the main vector of OROV and this virus rarely disseminated to the mosquito leg tissue in our study. Conclusions: Taken together, our findings show that sequential blood feeding enhances virus dissemination across diverse arbovirus-vector pairings, representing three mosquito genera and virus families, but a second BM was insufficient to overcome a strong midgut virus escape barrier in a nonnatural virus–vector pairing. [ABSTRACT FROM AUTHOR]

Camellia pleurocarpa (Gagnep.) Sealy, a species of yellow camellia indigenous to Vietnam, was investigated for its essential oil properties in this study. Hydrodistillation of its leaves yielded a complex mixture rich in sesquiterpenes and diterpenes. Chemical analysis identified 50 constituents, with notable compounds including spathulenol (13.26%), phytol (9.94%), and α-selinene (5.34%). The essential oil exhibited significant antimicrobial activity against three Gram-positive bacteria Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus; one Gram-negative bacterium Pseudomonas aeruginosa; and one yeast Candida albicans, with minimum inhibitory concentration (MIC) values ranging from 16 to 32 μg/mL and half-maximal inhibitory concentration (IC50) values ranging from 7.26 to 16.23 μg/mL. Furthermore, it demonstrated larvicidal potential against Aedes aegypti and Culex quinquefasciatus mosquitoes, with LC50 values ranging from 13.49 to 28.95 μg/mL and LC90 values ranging from 28.29 to 53.24 μg/mL. These findings underscore the promising antimicrobial and mosquito larvicidal properties of C. pleurocarpa essential oil, suggesting its potential as a natural alternative in combating microbial infections and controlling mosquito-borne diseases. This study represents the first comprehensive report on the chemical compositions and bioactivities of C. pleurocarpa essential oil. [ABSTRACT FROM AUTHOR]

Gravid culicine mosquitoes rely on olfactory cues for selecting breeding sites containing organic detritus. While this capacity of the mosquitoes is used for surveillance and control, the current methodology is unwieldy, unreliable and expensive in time and labour. This study evaluated the dose-dependent attraction and oviposition response of gravid Culex quinquefasciatus to alfalfa infusions. Through combined chemical and electrophysiological analyses, bioactive volatile organic compounds (VOCs) in the headspace of alfalfa infusions, eliciting attraction, were identified. While phenolic and indolic compounds were the most abundant bioactive VOCs, additional VOCs, including a monoterpene, were required to elicit a significant behavioural response to the synthetic odour blend of alfalfa infusions. Comparative analysis with the commercially available mosquito oviposition pheromone (MOP) was also conducted demonstrating that this standardised synthetic alfalfa infusion odour blend offers a promising lure for targeted surveillance and control of Culex mosquitoes, which may contribute to disease prevention and public health protection. [ABSTRACT FROM AUTHOR]

Phylogenetic analyses showed that the virus responsible for a May 2024 Oropouche fever outbreak in Cuba was closely related to viruses from Brazil in 2023. Pools of Ceratopogonidae spp. biting midges and Culex quinquefasciatus mosquitoes were positive for Oropouche viral RNA. No cases were severe. Virus extension to new areas may increase case numbers and severity [ABSTRACT FROM AUTHOR]

The prevalence of mosquito-borne diseases is increasing due to urbanization and climate change. Synthetic insecticides have resulted in resistance, and alternative control methods are needed. This study evaluated hexane, chloroform, and methanol extracts from Sphaeranthus indicus leaves for their efficacy against the larvae, pupae and eggs of Aedes aegypti and Culex quinquefasciatus mosquitoes. The plant materials were coarsely powdered and sequentially extracted in hexane, chloroform, and methanol using a Soxhlet apparatus, followed by filtration and concentration under reduced pressure with a rotary vacuum evaporator. In the case of Ae. aegypti, the hexane extract exhibited notable toxicity against all three examined stages. The LC50 values for larval mortality, pupal lethality, and ovicidal activity were determined to be 81.83 ppm, 86.13 ppm, and 63.2 ppm, respectively. Similarly, for Cx. quinquefasciatus, the hexane extract showed efficacy with LC50 values of 81.23 ppm for larval mortality, 93.24 ppm for pupal lethality, and 75.2 ppm for ovicidal activity. Following the hexane extract, the chloroform and methanol extracts demonstrated moderate larvicidal and pupicidal activity against both mosquito species, but they exhibited limited effectiveness against ovicidal activity. These findings suggest the potential use of natural extracts as supplementary control measures against mosquito vectors. [ABSTRACT FROM AUTHOR]

The global distribution of Aedes aegypti mosquitoes, particularly in tropical regions, poses a significant public health risk due to their apparent ability to transmit arboviruses such as West Nile virus (WNV). This study aimed to evaluate the vector competence of Ae. aegypti from São Tomé and Príncipe (STP) for the transmission of the WNV PT6.39 strain, considering its potential role as a bridge vector in a region where Culex quinquefasciatus would be the main vector. Aedes aegypti mosquitoes were collected, reared, and experimentally infected with WNV, with viral dissemination and transmission potential assessed 7, 14, and 21 days post infection (dpi). The results showed an increasing trend in infection rates, from 5% at 7 dpi to 35% at 21 dpi, with corresponding dissemination rates of 0%, 100%, and 43%. The transmission rates also increased from 0% at 7 dpi to 67% at 21 dpi, with a maximum transmission efficiency of 10% observed at the final time point. Although Ae. aegypti from STP demonstrated the potential to transmit WNV, the overall transmission efficiency remained relatively low. These findings provide necessary insights into the vector competence of Ae. aegypti in this region, highlighting the importance of continued monitoring and targeted vector control measures to mitigate the risk of potential WNV outbreaks. [ABSTRACT FROM AUTHOR]

BACKGROUND: Vector mosquito control is important for preventing and controlling mosquito‐borne infectious diseases. This study designed and developed a mosquito killer (MK) with a specific light wavelength, simulated human body temperature, human odor, and a photocatalyst to stimulate CO2 based on the physiological characteristics and ecological habits of mosquitoes. We tested the trapping effect of individual and multiple mosquito‐trapping elements of the MK through two‐way selection experiments and compared them with several commercial mosquito traps. RESULTS: The 365 nm wavelength MK was significantly more effective than the 395 nm (Cx. quinquefasciatus: 62.00% vs. 34.25%; Ae. albopictus: 50.75% vs 45.00%, An. sinensis: 49.75% vs 39.00%). Mosquitoes captured by the MK with heaters at 365 nm were significantly more than those captured by the MK without heaters at 365 nm. A trap with a 365 nm wavelength, heating element, and lure showed significantly better capture effectiveness than MK with a 365 nm wavelength, heating element, but without lure (Cx. quinquefasciatus: 67.00% vs. 29.75%, Ae. albopictus: 60.25% vs 36.25%, An. sinensis: 49.75% vs 39.75%). The coated photocatalyst trap with a 365 nm wavelength, heating element, and lure showed significantly better capture effectiveness than the trap without coating (Cx. quinquefasciatus: 54.25% vs. 42.50%; Ae. albopictus: 53.50% vs 44.00%, An. sinensis: 50.00% vs 41.25%). This trap demonstrated a significantly better capture advantage for Cx. quinquefasciatus and Ae. albopictus compared to the three commercial products. CONCLUSION: The developed mosquito trap with multiple attractant factors significantly enhanced the capture effectiveness of common mosquitoes. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Mosquitoes are the best‐known disease vectors for most vector‐borne diseases that significantly impact global health in terms of morbidity and mortality. In a geographical area, mosquito faunal diversity often alters with changing climatic factors and variable breeding habitats that differ across seasons. Using biodiversity indicators as tools, a study was conducted in rural, peri‐urban, and urban areas of district Ganjam, Odisha state, to determine mosquito faunal diversity as an approach to forecast the possible risk of disease transmission in the three representative topographies. A two‐year study was undertaken to assess the alpha diversity of mosquito species by the numerical strength of the species using various eco‐diversity indices. Species richness and abundance of mosquito species are significantly higher in peri‐urban areas compared to urban and rural areas. The species dominance of Culex quinquefasciatus was observed in all three topographies, while Aedes aegypti, Aedes albopictus, and Anopheles stephensi were in urban areas. Species richness may dilute the risk of disease in an area, but increased species dominance, mostly vector species, in a new habitat often allows pathogens to infect newer communities at risk, leading to the emergence of new diseases. The current study indicates the possible risk of lymphatic filariasis (LF) infection in all three topographies. On the other hand, the risk of malaria and dengue/chikungunya transmission is higher in urban areas. With routine entomological monitoring, including vector incrimination, the biodiversity indicators will be the best tool to forecast the risk of vector‐borne diseases in an area; accordingly, judicious vector control strategies can be adopted. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop pyrazolidine-3,5-dione derivatives with potential as environmentally friendly pesticides for pest control, specifically focusing on their efficacy as larvicidal agents. A novel one-pot synthesis of multicomponent pyrazolidine-3,5-dione derivatives (1a-m) was accomplished via the grindstone method using Cu(II)tyrosinase enzyme as a catalyst under mild reaction conditions, yielding 84%–96%. The synthesised derivatives (1a-m) were characterized using various spectroscopic methods (mass spectrometry, elemental analysis, FT-IR, and 1H and 13C NMR). NMR characterisation using DMSO-d6 as a solvent. The larvicidal and antifeedant activities of the synthesised compounds were screened and in silico computational studies were performed. The larvicidal activity against Culex quinquefasciatus and antifeedant activity against Oreochromis mossambicus were evaluated. Among the synthesised compounds, compound 1c demonstrated superior efficacy (LD50: 9.7 μg/mL) against C. quinquefasciatus compared to permethrin (LD50: 17.1 μg/mL). Regarding antifeedant activity, compounds 1a, 1e, 1f, 1j, and 1k exhibited 100% mortality at 100 μg/mL. Molecular docking analysis was performed to assess the binding capacity of a mosquito odorant-binding protein (3OGN) from Culex quinquefasciatus to compound 1c. The results revealed that compound 1c had a docking score of -10.4 kcal/mol, surpassing that of standard permethrin (-9.5 kcal/mol). Furthermore, DFT calculations were conducted to acquire theoretical data aligned with the experimental FT-IR results. According to experimental research, compound 1c demonstrates promising larvicidal activity against mosquito larvae of C. quinquefasciatus. [ABSTRACT FROM AUTHOR]

The ongoing epidemic of flaviviruses worldwide has underscored the importance of studying flavivirus vector competence, considering their close association with mosquito vectors. Tembusu virus is an avian-related mosquito-borne flavivirus that has been an epidemic in China and Southeast Asia since 2010. However, the reason for the outbreak of Tembusu virus in 2010 remains unclear, and it is unknown whether changes in vector transmission played an essential role in this process. To address these questions, we conducted a study using Culex quinquefasciatus as a model for Tembusu virus infection, employing both oral infection and microinjection methods. Our findings confirmed that both vertical and venereal transmission collectively contribute to the cycle of Tembusu virus within the mosquito population, with persistent infections observed. Importantly, our data revealed that the prototypical Tembusu virus MM_1775 strain exhibited significantly greater infectivity and transmission rates in mosquitoes than did the duck Tembusu virus (CQW1 strain). Furthermore, we revealed that the viral E protein and 3′ untranslated region are key elements responsible for these differences. In conclusion, our study sheds light on mosquito transmission of Tembusu virus and provides valuable insights into the factors influencing its infectivity and transmission rates. These findings contribute to a better understanding of Tembusu virus epidemiology and can potentially aid in the development of strategies to control its spread. [ABSTRACT FROM AUTHOR]

Background: Microbial larvicides containing both LysiniBacillus sphaericus and Bacillus thuringiensis svar. israelensis (Bti) insecticidal crystals can display advantages for mosquito control. This includes a broader action against larvae that are refractory to the Binary (Bin) toxin from L. sphaericus, as Bin-resistant Culex quinquefasciatus and Aedes aegypti naturally refractory larvae, which often co-habit urban areas of endemic countries for arboviruses. Our principal goal was to assess the toxicity of a combined L. sphaericus/Bti larvicide (Vectomax FG™) to Cx. quinquefasciatus (susceptible CqS and Bin-resistant CqR) and Ae. aegypti (Rocke) and to determine its persistence in the breeding sites with those larvae. Methods: The toxicity of a combined L. sphaericus/Bti product (VectoMax FG™) to larvae was performed using bioassays, and persistence was evaluated in simulate field trials carried out under the shade, testing two label concentrations during 12 weeks. A laboratory strain SREC, established with CqS and CqR larvae, was kept during four generations to evaluate the ability of the L. sphaericus/Bti to eliminate resistant larvae. Results: The L. sphaericus/Bti showed toxicity (mg/L) to larvae from all strains with a decreasing pattern for CqS (LC50 = 0.006, LC90 = 0.030), CqR (LC50 = 0.009, LC90 = 0.069), and Rocke (LC50 = 0.042, LC90 = 0.086). In a simulated field trial, the larvicide showed a persistence of 6 weeks and 8 weeks, controlling larvae from all strains in containers with 100 L of water, using 2 g or 4 g per container (100 L), respectively. The treatment of SREC larvae with L. sphaericus/Bti showed its capacity to eliminate the Bin-resistant individuals using suitable concentrations to target those larvae. Conclusions: Our results showed the high efficacy and persistence of the L. sphaericus/Bti larvicide to control Cx. quinquefasciatus and Ae. aegypti that might cohabit breeding sites. These findings demonstrated that such larvicides can be an effective tool for controlling those species in urban areas with a low potential for selecting resistance. [ABSTRACT FROM AUTHOR]

Background: Antananarivo, the capital city of Madagascar, is experiencing a steady increase in population growth. Due to the abundance of mosquito vectors in this locality, the population exposed to mosquito-borne diseases is therefore also increasing, as is the risk of epidemic episodes. The aim of the present study was to assess, in a resource-limited setting, the information on mosquito population dynamics and disease transmission risk that can be provided through a longitudinal entomological study carried out in a multi-host single site. Methods: Mosquitoes were collected every 15 days over 16 months (from January 2017 to April 2018) using six CDC-light traps in a peri-urban area of Antananarivo. Multivariable generalised linear models were developed using indoor and outdoor densities of the predominant mosquito species as response variables and moon illumination, environmental data and climatic data as the explanatory variables. Results: Overall, 46,737 mosquitoes belonging to at least 20 species were collected, of which Culex antennatus (68.9%), Culex quinquefasciatus (19.8%), Culex poicilipes (3.7%) and Anopheles gambiae sensu lato (2.3%) were the most abundant species. Mosquito densities were observed to be driven by moon illumination and climatic factors interacting at different lag periods. The outdoor models demonstrated biweekly and seasonal patterns of mosquito densities, while the indoor models demonstrated only a seasonal pattern. Conclusions: An important diversity of mosquitoes exists in the peri-urban area of Antananarivo. Some well-known vector species, such as Cx. antennatus, a major vector of West Nile virus (WNV) and Rift-Valley fever virus (RVFV), Cx. quinquefasciatus, a major vector of WNV, Cx. poicilipes, a candidate vector of RVFV and An. gambiae sensu lato, a major vector of Plasmodium spp., are abundant. Importantly, these four mosquito species are present all year round, even though their abundance declines during the cold dry season, with the exception of Cx. quinquefasciatus. The main drivers of their abundance were found to be temperature, relative humidity and precipitation, as well as—for outdoor abundance only—moon illumination. Identifying these drivers is a first step towards the development of pathogen transmission models (R0 models), which are key to inform public health stakeholders on the periods of most risk for vector-borne diseases. [ABSTRACT FROM AUTHOR]

Endophytic fungal molecules have the potential to be a cost-effective chemical source for developing eco-friendly disease-controlling pharmaceuticals that target mosquito-borne illnesses. The primary aims of the study were to identify the fungus Fusarium begoniae larvicidal ability against Aedes aegypti, Culex quinquefasciatus, and Anopheles stephensi. The ethyl acetate extract demonstrated lethal concentrations that kill 50% of exposed larvae (LC50) and 90% of exposed larvae (LC90) for the 1st to 4th instar larvae of An. stephensi (LC50 = 54.821, 66.525, 68.250, and 73.614; LC90 = 104.56, 138.205, 150.415, and 159.466 μg/mL), Cx. quinquefasciatus (LC50 = 64.981, 36.505, 42.230, and 36.514; LC90 = 180.46, 157.105, 140.318, and 153.366 μg/ mL), and Ae. aegypti (LC50 = 74.890, 33.607, 52.173, and 26.974; LC90 = 202.56, 162.205, 130.518, and 163.286 μg/mL). Mycelium metabolites were evaluated for their pupicidal activity towards Ae. aegypti (LC50 = 80.669, LC90 = 119.904), Cx. quinquefasciatus (LC50 = 70.569, LC90 = 109.840), and An. stephensi (LC50 = 73.269, LC90 = 110.590 μg/mL). The highest larvicidal activity was recorded at 300 µg/mL, with 100% mortality against first and second-instar larvae of Cx. quinquefasciatus. Metabolite exposure to larvae exhibited several abnormal behavioral changes. The exposure to F. begoniae metabolite, key esterases such as acetylcholinesterase, α-and-β-carboxylesterase, and acid and alkaline phosphatase activity significantly decreased compared to control larvae. The outcomes of the histology analysis revealed that the mycelium metabolites-treated targeted larvae had a disorganized abdominal mid and hindgut epithelial cells. The is first-hand information on study of ethyl-acetate-derived metabolites from F. begoniae tested against larvae and pupae of Ae. aegypti, Cx. quinquefasciatus and An. stephensi. Bio-indicator toxicity findings demonstrate that A. nauplii displayed no mortality. [ABSTRACT FROM AUTHOR]

Vector-borne diseases resulted into several cases of human morbidity and mortality over the years and among them is filariasis, caused by the mosquito Culex quinquefasciatus. Developing novel strategies for mosquito control without jeopardizing the environmental conditions has always been a topic of discussion and research. Integrated Vector Management (IVM) emphasizes a comprehensive approach and use of a range of strategies for vector control. Recent research evaluated the use of two entomopathogenic fungi; Beauveria bassiana and Lecanicillium lecanii in IVM, which can serve as potential organic insecticide for mosquito population control. However, their combined efficacy has not yet been evaluated against mosquito control in prior research and a gap of knowledge is still existing. So, this research was an attempt to bridge up the knowledge gap by (1) Assessing the combined efficacy of Beauveria bassiana and Lecanicillium lecanii on Culex quinquefasciatus (2) To investigate the sub-lethal concentration (LC50) of the combined fungal concentration and (3) To examine the post-mortem effects caused by the combined fungal concentration under Scanning Electron Microscope (SEM). The larval pathogenicity assay was performed on 4th instar C. quinquefasciatus larvae. Individual processed fungal solution of B. bassiana and L. lecanii were procured and to test the combined efficacy, the two solutions were mixed in equal proportions. To evaluate the sub-lethal concentration (LC50), different concentrations of the combined fungal solution were prepared by serial dilations. The mortality was recorded after 24 hours for each concentration. Upon treatment and evaluation, The LC50 values of B. bassiana and L. lecanii were 0.25 x 104 spores/ml and 0.12 x 104 spores/ml respectively and the combined fungal concentration was 0.06 x 103 spores/ml. This clearly indicated that the combined efficacy of the fungi is more significant. Further, SEM analysis revealed morphological deformities and extensive body perforations upon combined fungal treatment. These findings suggested that combining the two fungi can be a more effective way in controlling the population of Culex quinquefasciatus. [ABSTRACT FROM AUTHOR]

Abundance and seasonal composition of adult indoor resting Culicine mosquitoes in Dutse were studied between April to September 2021. Culex pipiens complex and Aedes species has been proven as the potential vectors of public health importance. However, their abundance and seasonal composition has not been adequately studied in Dutse, Northwest Nigeria to document their vectorial profile. This study was designed to fill the gap. Adult indoor resting mosquitoes were collected using Pyrethrum Spray catch (PSC) from April - September 2021 and were morphologically and molecularly identified using keys and polymerase chain reaction (PCR). Data generated were analysed using Statistical Package for Social Sciences (SPSS). 2656 mosquitoes, comprising Culex quinquefasciatus (2507) and Aedes species (149) were collected. Culex quinquefasciatus was the most abundant species (94.4%) collected while the least were Aedes species (5.6%). The results revealed that in Jidawa, more Culex quinquefasciatus (80) were collected in August while the least were collected in June (25). For Aedes mosquitoes, higher collection (75) was realised in April while July recorded zero collection. The monthly variation of the mosquitoes showed the peak in the month of April (690) and May (300) in Jidawa when compared to Kargo (430) and (100) respectively. In the dry season, more mosquitoes were collected In Jidawa while in Kargo more were collected during the wet seasons. The result of the molecular identification of the Culex pipiens complex reveals Culex quinquefasciatus as the only sibling species in both Jigawa and Kargo. The occurrence of Culex quinquefasciatus and Aedes species is an indication of the signal against lymphatic filariasis, dengue fever, arbovirus and yellow fever in the area. Therefore, there is need for vector control programmes and public orientation on the drivers of mosquito abundance in the study area, taking into cognisance the seasonality variation of the mosquitoes. [ABSTRACT FROM AUTHOR]

In an age of emerging zoonoses, it is important to understand the intricate system of vectors and reservoirs, or hosts, and their relation to humans. West Nile Virus (WNV) has been detected in a myriad of nonhuman hosts. Transmission of the virus to humans is reliant on amplified seroprevalence within the host, which occurs primarily in birds. However, recent studies have found that other animal groups, including crocodilians, can obtain seroprevalence amplification to levels that make them competent hosts able to transmit WNV to mosquitoes, which can then transmit to humans. Climate change could exacerbate this transmission risk by shifting the distributions of mosquito vectors towards novel geographic ranges. Here, we use maximum entropy models to map the current and future distributions of three mosquito vector species and four crocodilian species in North America to determine the emerging risk of WNV outbreaks associated with changing climates and WNV associated with crocodilians in North America. From our models, we determined that one mosquito species in particular, Culex quinquefasciatus, will increase its distribution across the ranges of all crocodilian species in all tested climate change scenarios. This poses a potential risk to public health for people visiting and living near crocodilian farms and high-density natural crocodilian populations. [ABSTRACT FROM AUTHOR]

Abstract Background The recent rise in the transmission of mosquito-borne diseases such as dengue virus (DENV), Zika (ZIKV), chikungunya (CHIKV), Oropouche (OROV), and West Nile (WNV) is a major concern for public health managers worldwide. Emerging technologies for automated remote mosquito classification can be supplemented to improve surveillance systems and provide valuable information regarding mosquito vector catches in real time. Methods We coupled an optical sensor to the entrance of a standard mosquito suction trap (BG-Mosquitaire) to record 9151 insect flights in two Brazilian cities: Rio de Janeiro and Brasilia. The traps and sensors remained in the field for approximately 1 year. A total of 1383 mosquito flights were recorded from the target species: Aedes aegypti and Culex quinquefasciatus. Mosquito classification was based on previous models developed and trained using European populations of Aedes albopictus and Culex pipiens. Results The VECTRACK sensor was able to discriminate the target mosquitoes (Aedes and Culex genera) from non-target insects with an accuracy of 99.8%. Considering only mosquito vectors, the classification between Aedes and Culex achieved an accuracy of 93.7%. The sex classification worked better for Cx. quinquefasciatus (accuracy: 95%; specificity: 95.3%) than for Ae. aegypti (accuracy: 92.1%; specificity: 88.4%). Conclusions The data reported herein show high accuracy, sensitivity, specificity and precision of an automated optical sensor in classifying target mosquito species, genus and sex. Similar results were obtained in two different Brazilian cities, suggesting high reliability of our findings. Surprisingly, the model developed for European populations of Ae. albopictus worked well for Brazilian Ae. aegypti populations, and the model developed and trained for Cx. pipiens was able to classify Brazilian Cx. quinquefasciatus populations. Our findings suggest this optical sensor can be integrated into mosquito surveillance methods and generate accurate automatic real-time monitoring of medically relevant mosquito species. Graphical Abstract

Abstract The ongoing epidemic of flaviviruses worldwide has underscored the importance of studying flavivirus vector competence, considering their close association with mosquito vectors. Tembusu virus is an avian-related mosquito-borne flavivirus that has been an epidemic in China and Southeast Asia since 2010. However, the reason for the outbreak of Tembusu virus in 2010 remains unclear, and it is unknown whether changes in vector transmission played an essential role in this process. To address these questions, we conducted a study using Culex quinquefasciatus as a model for Tembusu virus infection, employing both oral infection and microinjection methods. Our findings confirmed that both vertical and venereal transmission collectively contribute to the cycle of Tembusu virus within the mosquito population, with persistent infections observed. Importantly, our data revealed that the prototypical Tembusu virus MM_1775 strain exhibited significantly greater infectivity and transmission rates in mosquitoes than did the duck Tembusu virus (CQW1 strain). Furthermore, we revealed that the viral E protein and 3′ untranslated region are key elements responsible for these differences. In conclusion, our study sheds light on mosquito transmission of Tembusu virus and provides valuable insights into the factors influencing its infectivity and transmission rates. These findings contribute to a better understanding of Tembusu virus epidemiology and can potentially aid in the development of strategies to control its spread.

Abstract Mosquito-borne diseases, such as malaria, dengue, and Zika, pose major public health challenges globally, affecting millions of people. The growing resistance of mosquito populations to synthetic insecticides underscores the critical need for effective and environmentally friendly larvicides. Although chemical pesticides can initially be effective, they often lead to negative environmental consequences and health hazards for non-target species, including humans. This study aimed to evaluate the larvicidal effects of Trachyspermum ammi essential oil and Delphinium speciosum extract on the larvae of three major mosquito species: Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. Mosquito larvae of Ae. aegypti, An. stephensi, and Cx. quinquefasciatus were reared under controlled laboratory conditions. The larvicidal activity of T. ammi essential oil and D. speciosum extract was evaluated through standard bioassays, using various concentrations of essential oils (10, 20, 40, 80, and 160 ppm) and extracts (160, 320, 640, 1280, and 2560 ppm) to determine the lethal concentration (LC50) values after 24 h of exposure. Fresh plant materials were collected, with the essential oil extracted via hydro-distillation, and the extract prepared using methanol solvent extraction. The chemical composition of T. ammi essential oil was examined using gas chromatography-mass spectrometry (GC-MS). Additionally, the preliminary analysis of the chemical compounds in D. speciosum extract was carried out using thin layer chromatography (TLC) and nuclear magnetic resonance spectroscopy (NMR) techniques. The results indicated that the essential oil of T. ammi exhibited more effective larvicidal activity compared to the D. speciosum extract. Specifically, the essential oil demonstrated LC50 values of 18 ppm for Cx. quinquefasciatus and 19 ppm for Ae. aegypti. In contrast, the D. speciosum extract showed the strongest larvicidal effect against An. stephensi, with an LC50 of 517 ppm. Concentrations of 40 ppm of the essential oil and 1280 ppm of the extract resulted in 100% mortality across all three species. Both the essential oil of T. ammi and the D. speciosum extract exhibited concentration-dependent larvicidal activity, and these results were statistically significant (p

BACKGROUND: Spinosad consists of spinosyn A and spinosyn D that are produced by the soil‐dwelling actinomycete Saccharopolyspora spinosa. It has been used to control a wide variety of arthropod pests of economic importance. Formulations of spinosad have been used to control larval mosquitoes since approximately 2010. However, the target site‐ and metabolism‐based resistance to this neurotoxin has been reported since 2000 in agricultural pests The current studies aim to further evaluate resistance risk and develop resistance prevention tactics in the southern house mosquito Culex quinquefasciatus. RESULTS: The first comparison group involved selection at lethal concentration, 75% (LC75) of technical spinosad for 30 generations, resulting in baseline resistance ratios (RRs) of 51.1‐fold at LC50 and 45.4‐fold at LC90 in Cx. quinquefasciatus. However, under the same conditions, selection by a combination of spinosad and Bacillus thuringiensis subsp. israelensis (B.t.i.), negated resistance development to spinosad, RRs ranging 1.00–1.75‐fold at LC50 and 0.83–1.76‐fold at LC90. At the same time, the selected population remained susceptible to the combination throughout the selection process, RRs fluctuating 0.74–1.38‐fold at LC50 and 0.63–1.23‐fold at LC90. CONCLUSION: Combination of spinosad and B.t.i. negates resistance development to spinosad, as opposed to spinosad alone in Cx. quinquefasciatus. Moreover, the species tested does not develop resistance to this combination upon repeated exposures, implying the potential for further developing this combination as a viable product for larval mosquito control. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: The incompatible insect technique (IIT) has been used for Aedes mosquito population suppression to curb the transmission of dengue. However, its wide application is limited owing to the low output of male mosquitoes and the risk of population replacement from the release of fertile Wolbachia‐infected females. This study aims to improve IIT efficiency for broader adoption. RESULTS: We assessed the impact of 10% pyriproxyfen (PPF) sticky powder exposure on Wolbachia (from Culex molestus)‐transinfected Aedes albopictus Guangzhou line (GUA line) (GC) mosquitoes. We found that the exposure caused chronic toxicity in adult mosquitoes without affecting the cytoplasmic incompatibility (CI)‐inducing capability of males. The PPF‐contaminated GC females exhibited significant sterilization and the ability to disseminate lethal doses of PPF to breeding sites. Subsequently, we conducted a field trial combining PPF with IIT aiming to suppress the Ae. albopictus population. This combined approach, termed boosted IIT (BIIT), showed a notable enhancement in population suppression efficiency. The improved efficacy of BIIT was attributed to the dispersion of PPF particles in the field via the released PPF‐contaminated male mosquitoes. During the BIIT field trial, no Wolbachia wPip‐positive Ae. albopictus larvae were detected, indicating the effective elimination of the risk of Wolbachia‐induced population replacement. Additionally, the field trial of BIIT against Ae. albopictus resulted in the suppression of the nontarget mosquito species Culex quinquefasciatus. CONCLUSION: Our results highlight the remarkable efficiency and feasibility of combining IIT with PPF in suppressing mosquito populations, facilitating the widespread implementation of IIT‐based management of mosquito‐borne diseases. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Abstract The study was formulated to identify the effect of Mangifera indica leaf extract in inhibiting the growth and metamorphosis of Culex quinquefasciatus larva. Bioassay-guided extraction identified the bioactive fraction, after which GC-MS characterized it. The larvicidal activity was analyzed by administrating extract in various concentrations and then subjecting the mortality rate for probit analysis. The morphological and physiological impact upon larvae was understood by histological analysis and acetylcholinesterase activity assay. The results suggested that the extract possessed a high degree of larvicidal activity, whereas the Dose50 was 225.158 ± 15.168 with a Total Chi-Square of 13.09 and p-value of 0.11. The histological studies revealed notable aberrations among the study subjects compared to the control group due to diminished abdominal tissue integrity. It was also observed that the extract could inhibit the acetylcholinesterase activity, with an LD 50 of 0.9512 µg/ml. The observations made in these studies may be utilized to develop a potential larvicidal agent that could act upon multiple targets.

Abstract Background Environmental factors influence the mosquito behavior, particularly the oviposition behavior. Therefore, understanding the response of mosquitoes to their environmental conditions like photoperiod, humidity, rainfall, etc., can lead to more precise predictions of transmission cycles which help in the development of more effective vector control strategies. To understand the importance of photoperiod in determining the oviposition cycle of Anopheles subpictus and Culex quinquefasciatus, experiments were conducted under different conditions of normal light (LD 12: 12), reversed photoperiod (DL 12: 12) and continuous light (24 LL) for three consecutive days. Results It was noticed that ovipositional activity was exclusively restricted to the scotophase. When both the mosquito species were exposed to reverse photoperiod, the oviposition activity also reversed but they showed an erratic oviposition behavior when exposed to 24 h light condition. Conclusions Understanding the oviposition behavior of mosquito species may favor to design and develop new vector control strategies.

Abstract Lymphatic filariasis (LF) is a crippling and disfiguring parasitic condition. India accounts for 55% of the world’s LF burden. The filarial parasite Wuchereria bancrofti is known to cause 99.4% of the cases while, Brugia malayi accounts for 0.6% of the issue occurring mainly in some pockets of Odisha and Kerala states. The Balasore (Baleswar) district of Odisha has been a known focus of B. malayi transmission. We employed molecular xenomonitoring to detect filarial parasite DNA in vectors. In six selected villages, Gravid traps were used to collect Culex mosquitoes and hand catch method using aspirators was followed for collection of mansonioides. A total of 2903 mosquitoes comprising of Cx. quinquefasciatus (n = 2611; 89.94%), Cx. tritaeniorhynchus (n = 100; 3.44%), Mansonia annuliferea (n = 139; 4.78%) and Mansonia uniformis (n = 53; 1.82%) were collected from six endemic villages. The species wise mosquitoes were made into 118 pools, each with a maximum of 25 mosquitoes, dried and transported to the laboratory at VCRC, Puducherry. The mosquito pools were subjected to parasite DNA extraction, followed by Real-time PCR using LDR and HhaI probes to detect W. bancrofti and B. malayi infections, respectively. Seven pools (6.66%) of Cx. quinquefasciatus, showed infection with only W. bancrofti while none of the pools of other mosquito species showed infection with either W. bancrofti or B. malayi. Although the study area is endemic to B. malayi, none of the vectors of B. malayi was found with parasite infection. This study highlights the ongoing transmission of bancroftian filariasis in the study villages of Balasore district of Odisha and its implications for evaluating LF elimination programme.

Background and Aim: Mosquitoes carry numerous diseases of medical and veterinary significance. While citronella essential oil is safe as a mosquito repellent, extensive research does not document its ability to deter mosquitoes from animals. This study assessed the citronella essential oil bath bomb’s ability to repel Culex quinquefasciatus mosquitoes in dogs. Materials and Methods: Citronella essential oil’s chemical composition was analyzed using gas chromatography-mass spectrometry (GC-MS). Through freeze-thaw testing, a bath bomb formulation containing 6% w/w citronella essential oil was assessed for its physical and chemical stability. Thirty-two healthy client-owned mixed-breed dogs were employed to test the mosquito-repellency effects of citronella essential oil (treatment group) and olive oil (control group) bath bomb formulations. Bath bombs were tested for irritation effects on animal skin for 15-day post-application. Results: Thirty-six compounds were identified through GC-MS, with citronellal (23.38%), δ-cadinene (12.25%), and geraniol (9.09%) being the most prevalent constituents. The bath bomb maintained its original physical properties after undergoing six freeze-thawing cycles and retained over 90% of its citronella essential oil. About 100%, 69.28%, and 65.58% mosquito repellency were displayed by the citronella essential oil bath bomb at 3 h, 6 h, and 8 h, respectively. None of the test animals exhibited skin irritation during the study. Conclusion: The citronella bath bomb effectively repelled C. quinquefasciatus in dogs without irritating their skin. The formulation’s physical and chemical stability is demonstrated by the results of freeze-thaw stability testing. Further studies should be conducted to evaluate the repelling activity against other mosquito species.

West Nile virus (WNV) is the leading mosquito-borne disease causing-pathogen in the United States. Concerningly, there are no prophylactics or drug treatments for WNV and public health programs rely heavily on vector control efforts to lessen disease incidence. Insecticides can be effective in reducing vector numbers if implemented strategically, but can diminish in efficacy and promote insecticide resistance otherwise. Vector control programs which employ mass-fogging applications of insecticides, often conduct these methods during the late-night hours, when diel temperatures are coldest, and without a-priori knowledge on daily mosquito activity patterns. This study's aims were to 1) quantify the effect of temperature on the toxicity of two conventional insecticides used in fogging applications (malathion and deltamethrin) to Culex tarsalis, an important WNV vector, and 2) quantify the time of host-seeking of Cx. tarsalis and other local mosquito species in Maricopa County, Arizona. The temperature-toxicity relationship of insecticides was assessed using the WHO tube bioassay, and adult Cx. tarsalis, collected as larvae, were exposed to three different insecticide doses at three temperature regimes (15, 25, and 35°C; 80% RH). Time of host-seeking was assessed using collection bottle rotators with encephalitis vector survey traps baited with dry ice, first at 3h intervals during a full day, followed by 1h intervals during the night-time. Malathion became less toxic at cooler temperatures at all doses, while deltamethrin was less toxic at cooler temperatures at the low dose. Regarding time of host-seeking, Cx. tarsalis, Aedes vexans, and Culex quinquefasciatus were the most abundant vectors captured. During the 3-hour interval surveillance over a full day, Cx. tarsalis were most-active during post-midnight biting (00:00–6:00), accounting for 69.0% of all Cx. tarsalis, while pre-midnight biting (18:00–24:00) accounted for 30.0% of Cx. tarsalis. During the 1-hour interval surveillance overnight, Cx. tarsalis were most-active during pre-midnight hours (18:00–24:00), accounting for 50.2% of Cx. tarsalis captures, while post-midnight biting (00:00–6:00) accounted for 49.8% of Cx. tarsalis. Our results suggest that programs employing large-scale applications of insecticidal fogging should consider temperature-toxicity relationships coupled with time of host-seeking data to maximize the efficacy of vector control interventions in reducing mosquito-borne disease burden. Author summary: Mosquito-borne pathogens such as West Nile virus (WNV) are expected to increase due to climate change, and public health programs rely on insecticides to reduce mosquito vector populations. Insecticidal fogging is often conducted during post-midnight hours when temperatures are coldest. Temperature has been shown to impact the toxicity of insecticides, but this effect is understudied, particularly for WNV vectors. The researchers aimed to test the effect of temperature on the toxicity of two common insecticides to Culex tarsalis, a primary mosquito vector of WNV, and to identify when local vectors were actively seeking a host to bite. The research location was a productive riparian (wetland) area adjacent to many urban centers in Arizona. The researchers found that both insecticides became less toxic at colder temperatures and that early evening accounted for a significant portion of captures, yet is outside of normal fogging hours. Human outdoor activities also increase during these hours, which may result in elevated risk of disease transmission. This research serves to improve our understanding and usage of insecticides to reduce disease burden. As insecticides are used globally, the findings of this research may relate to all mosquito-borne diseases, including malaria, and are relevant for agricultural pest management. [ABSTRACT FROM AUTHOR]

Environmental pollution, being a major concern worldwide, needs a unique and ecofriendly solution. To answer this, researchers are aiming in utilizing plant extracts for the synthesis of nanoparticles. These NPs synthesized using plant extracts provide a potential, environmentally benign technique for biological and photocatalytic applications. Especially, plant leaf extracts have been safe, inexpensive, and eco-friendly materials for the production of nanoparticles in a greener way. In this work, zinc ferrite nanoparticles (ZnFe2O4 NPs) were prepared using Nyctanthes arbor-tristis leaf extract by hydrothermal method, and its biological and photocatalytic properties were assessed. The synthesized ZnFe2O4 NPs were characterized using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FT-IR). X-ray diffraction confirmed the arrangement of the fcc crystal structure of the nanoparticles and that some organic substances were encapsulated within the zinc ferrite. According to the SEM analysis, the resulting nanoparticles got agglomerated and spherical in shape. The ZnFe2O4 nanoparticles are in their pure form, and all of their elemental compositions were shown by the energy-dispersive X-ray analysis (EDAX) spectrum. The FTIR results revealed that the produced nanoparticles contained distinctive functional groups. Fluorescence spectroscopy was used to examine the binding affinities between bovine serum albumin (BSA) and ZnFe2O4 nanoparticles in terms of protein binding, stability, and conformation. The interaction between BSA and ZnFe2O4 NPs was examined using steady-state and time-resolved fluorescence measurements, and it was evident that static quenching occurred. The ability of ZnFe2O4 nanoparticles to kill Culex quinquefasciatus (C. quinquefasciatus) larvae was evaluated. The synthesized NPs demonstrated a noteworthy toxic effect against the fourth instar larvae of C. quinquefasciatus with LC50 values of 43.529 µg/mL and LC90 values of 276.867 µg/mL. This study revealed the toxicity of green synthesized ZnFe2O4 NPs on mosquito larvae, proving that these NPs are good and effective larvicides. Furthermore, the ZnFe2O4 NPs were utilized for dye degradation of methylene blue under visible light treatment and achieved 99.5% degradation. [ABSTRACT FROM AUTHOR]

Musca domestica L., a common housefly, and Culex quinquefasciatus mosquito are quite well-known pests that can transfer a wide range of diseases to humans as well as animals. In this study, various isoborneol derivatives including esters, ethers, and thioethers were synthesized from isoborneol under mild conditions. These derivatives were evaluated for inhibition of house-fly M. domestica adults and Cx. quinquefasciatus larvae. Two of the synthesized isoborneol ester derivatives (2 and 3) showed good activity against both insect species. Additional two derivatives (6 and 9) were active against M. domestica L., and the derivatives (1–3, 8) were active against Cx. quinquefasciatus larvae. [ABSTRACT FROM AUTHOR]

Introduction: Culex quinquefasciatus is one of the most important carriers of human pathogens. Using the insecticides is one of the most important methods of combating this vector. But the genetic resistance created in Culex quinquefasciatus led to disruption in the fight against this pest. Consequently, it is necessary to know the level of resistance to fight this vector. Based on this, the present study was conducted to investigate the prevalence of kdr resistance in Culex quinquefasciatus against organochlorine insecticides in the world. Methods: This study was conducted by systematic review, and meta-analysis on the prevalence of kdr resistance and mortality rate in Culex quinquefasciatus against organochlorine insecticides in the world. All pertinent articles were extracted and analyzed in accordance with this information during an unrestricted search of the scientific databases Web of Science, PubMed, Scopus, biooan.org, Embase, ProQuest, and Google Scholar until the end of November 2023. Statistical analysis of data was done using fixed and random effects model in meta-analysis, I2 index, Cochran's test, and meta-regression by STATA version 17 software. Results: Seventy articles were included in the meta-analysis process. Based on the findings, the prevalence of Kdr in Culex quinquefasciatus against organochlorine insecticide was estimated at 63.1%. Moreover, the mortality rate against the insecticide deltamethrin was 46%, DDT 18.5%, permethrin 42.6%, malathion 54.4% and lambdacyhalothrin 53%. Conclusion: More than half of Cx. quinquefasciatus had Kdr. This vector was relatively resistant to DDT and permethrin insecticides and sensitive to malathion, deltamethrin and lambdacyhalothrin. In order to prevent the development of resistance to alternative insecticides, it is consequently critical to combat this vector with efficacious insecticides. Author summary: Using the insecticides is one of the most important methods of combating this vector. Based on this, the present study was conducted to investigate the prevalence of kdr resistance in Culex quinquefasciatus against organochlorine insecticides in the world. This study was conducted by systematic review, and meta-analysis on the prevalence of kdr resistance and mortality rate in Culex quinquefasciatus against organochlorine insecticides in the world. Based on the findings, the prevalence of Kdr in Culex quinquefasciatus against organochlorine insecticide was estimated at 63.1%. Moreover, the mortality rate against the insecticide deltamethrin was 46%, DDT 18.5%, permethrin 42.6%, malathion 54.4% and lambdacyhalothrin 53%. More than half of Cx. quinquefasciatus had Kdr. This vector was relatively resistant to DDT and permethrin insecticides and sensitive to malathion, deltamethrin and lambdacyhalothrin. [ABSTRACT FROM AUTHOR]

The study was formulated to identify the effect of Mangifera indica leaf extract in inhibiting the growth and metamorphosis of Culex quinquefasciatus larva. Bioassay-guided extraction identified the bioactive fraction, after which GC-MS characterized it. The larvicidal activity was analyzed by administrating extract in various concentrations and then subjecting the mortality rate for probit analysis. The morphological and physiological impact upon larvae was understood by histological analysis and acetylcholinesterase activity assay. The results suggested that the extract possessed a high degree of larvicidal activity, whereas the Dose50 was 225.158 ± 15.168 with a Total Chi-Square of 13.09 and p-value of 0.11. The histological studies revealed notable aberrations among the study subjects compared to the control group due to diminished abdominal tissue integrity. It was also observed that the extract could inhibit the acetylcholinesterase activity, with an LD 50 of 0.9512 µg/ml. The observations made in these studies may be utilized to develop a potential larvicidal agent that could act upon multiple targets. [ABSTRACT FROM AUTHOR]

Background: Environmental factors influence the mosquito behavior, particularly the oviposition behavior. Therefore, understanding the response of mosquitoes to their environmental conditions like photoperiod, humidity, rainfall, etc., can lead to more precise predictions of transmission cycles which help in the development of more effective vector control strategies. To understand the importance of photoperiod in determining the oviposition cycle of Anopheles subpictus and Culex quinquefasciatus, experiments were conducted under different conditions of normal light (LD 12: 12), reversed photoperiod (DL 12: 12) and continuous light (24 LL) for three consecutive days. Results: It was noticed that ovipositional activity was exclusively restricted to the scotophase. When both the mosquito species were exposed to reverse photoperiod, the oviposition activity also reversed but they showed an erratic oviposition behavior when exposed to 24 h light condition. Conclusions: Understanding the oviposition behavior of mosquito species may favor to design and develop new vector control strategies. [ABSTRACT FROM AUTHOR]

Avian malaria is expanding upslope with warmer temperatures and driving multiple species of Hawaiian birds towards extinction. Methods to reduce malaria transmission are urgently needed to prevent further declines. Releasing Wolbachia-infected incompatible male mosquitoes could suppress mosquito populations and releasing Wolbachia-infected female mosquitoes (or both sexes) could reduce pathogen transmission if the Wolbachia strain reduced vector competence. We cleared Culex quinquefasciatus of their natural Wolbachia pipientis wPip infection and transinfected them with Wolbachia wAlbB isolated from Aedes albopictus. We show that wAlbB infection was transmitted transovarially, and demonstrate cytoplasmic incompatibility with wild-type mosquitoes infected with wPip from Oahu and Maui, Hawaii. We measured vector competence for avian malaria, Plasmodium relictum, lineage GRW4, of seven mosquito lines (two with wAlbB; three with natural wPip infection, and two cleared of Wolbachia infection) by allowing them to feed on canaries infected with recently collected field isolates of Hawaiian P. relictum. We tested 73 groups (Ntotal = 1176) of mosquitoes for P. relictum infection in abdomens and thoraxes 6–14 days after feeding on a range of parasitemias from 0.028% to 2.49%, as well as a smaller subset of salivary glands. We found no measurable effect of Wolbachia on any endpoint, but strong effects of parasitemia, days post feeding, and mosquito strain on both abdomen and thorax infection prevalence. These results suggest that releasing male wAlbB-infected C. quinquefasciatus mosquitoes could suppress wPip-infected mosquito populations, but would have little positive or negative impact on mosquito vector competence for P. relictum if wAlbB became established in local mosquito populations. More broadly, the lack of Wolbachia effects on vector competence we observed highlights the variable impacts of both native and transinfected Wolbachia infections in mosquitoes. Author summary: Avian malaria is expanding upslope in Hawaii with warmer temperatures and driving multiple species of birds towards extinction. Methods to reduce malaria transmission are urgently needed to prevent further declines. Releasing male mosquitoes infected with a type of bacteria (Wolbachia) could suppress mosquito populations by reducing offspring viability and releasing Wolbachia-infected female mosquitoes (or both sexes) could reduce pathogen transmission if the Wolbachia strain reduced vector competence. We cleared Culex quinquefasciatus of their natural Wolbachia pipientis wPip infection and transinfected them with Wolbachia wAlbB isolated from Aedes albopictus. We show that wAlbB infection was transmitted to offspring, and mating wAlbB males with wild-type mosquitoes produced mostly inviable offspring. We measured susceptibility to avian malaria infection of mosquitoes with native or transinfected Wolbachia (wPip or wAlbB). We found no measurable effect of Wolbachia on susceptibility. These results suggest that releasing male wAlbB-infected C. quinquefasciatus mosquitoes could suppress Hawaiian mosquito populations, but would have little positive or negative impact on mosquito vector competence for avian malaria. More broadly, the lack of Wolbachia effects on susceptibility to avian malaria we observed highlights the variable impacts of both native and transinfected Wolbachia infections in mosquitoes. [ABSTRACT FROM AUTHOR]

The spatial pattern of many pathogens that are transmitted by mosquitoes (Diptera: Culicidae) is changing due to globalization and climate change. Thus, surveillance of mosquito vectors is becoming increasingly widespread as basis for risk assessment and control. Species identification by loop‐mediated isothermal amplification (LAMP) assays is simple, fast and reliable. Specific primers for several mosquito species are available (Aedes aegypti, Aedes albopictus, Aedes geniculatus, Aedes japonicus, Aedes koreicus, species of the Anopheles funestus group and An. gambiae complex). In the present work, LAMP assays targeting the rDNA internal transcribed spacer region were developed for Ae. cretinus, a minor sister taxon of Ae. albopictus, and for Culex pipiens/Culex quinquefasciatus and Culex torrentium. The specificities of the primers designed in silico were confirmed by in vitro tests with DNA form non‐target species. Further, the release of DNA from mosquito stages (eggs, larvae, pupae, adults) was investigated, revealing that an incubation for 5 min at 80°C in water is suitable for LAMP. With this method, one specimen (egg, larva, pupa, adult) of a target species could be detected among 49 non‐targets. Thus, the assays are suitable for fast and reliable identification of mosquito species of all life stages by colour change visible to the naked eye, and they are operable under field conditions. [ABSTRACT FROM AUTHOR]

Failure of conventional mosquito control strategies to curb the population of vectors have made the humans vulnerable to serious medical problems transmitted by them. This effect has been compounded by global climate change enabling the mosquitoes to cross geographical boundaries and cause trouble in regions where they were initially not found. As such, the scientific community has been compelled to devise alternative and innovative strategies of mosquito control that can be integrated with the conventional practices to implement multi-phasic approach of vector management. Culex quinquefasciatus is one such mosquito species that is reported to be one of the primary vectors of lymphatic filariasis and many other diseases of global health concern. However, not much is known about its breeding habitat ecology and microbial properties that have enabled the species to achieve reproductive success in urbanized habitats. The current investigation was carried out at Digha, West Bengal, India. The region, despite being endemic for lymphatic filariasis, has rarely been explored for its mosquito diversity and/or their breeding habitat characteristics. Therefore, these were attempted. For survey and sampling, seven villages were chosen, namely, Duttapur, Jatimati, Champabani, Padima, Gobindabasan, Bhagibaharampur and Palsandapur. The study showed that Cx. quinquefasciatus is the dominant mosquito species at the sampling sites with the highest density of their larvae being recorded from man-made structures like drains and pools close to human habitations and livestock. The study was, therefore, restricted to Cx. quinquefasciatus. Seasonal abundance showed that they were most prevalent in the monsoon followed by summer. The physicochemical characterization showed their larvae to prefer almost neutral pH (6.9 to 7.3), low chloride concentration (98 to 258 ppm) and turbidity. As far as other parameters are concerned, they were tolerant towards a wide range allowing them to adapt varied habitats in the study areas. The bacterial profiling of their natural habitat waters revealed the presence of Paenibacillus nanensis DGX1(OQ690670), Bacillus cereus DGX2(OQ690675), Bacillus sp. DGX3(OQ690700) and Escherichia coli DGX4(OQ690701). Bacillus cereus was found to have high oviposition attractant properties in oviposition assays. Bacillus cereus was also obtained from the midgut of third instar larvae indicating that they had entered from the surrounding medium and colonized the larval gut. Subsequent tests exhibited the roles of B. cereus in larval development. Numerous plant products have been reported either as insecticides for killing larvae or adult mosquitoes or as repellents for mosquito biting and the best alternatives for mosquito control. Larvicidal potential of emulsified neem oil formulation against the field collected 3rd instar larvae of Culex quinquefasciatus mosquito under laboratory conditions was also evaluated. The information thus obtained can be pooled to generate larval source markers and larval source management practices by altering their habitats that cannot be removed. Furthermore, the time of implementation of these strategies can also be planned. [ABSTRACT FROM AUTHOR]

Mosquitoes, notorious for their deadly impact as disease vectors, also hold economic value owing to their roles in disease transmission. The present study focuses on the importance of understanding mosquito gut microbiota for implementing innovative vector control strategies, thereby mitigating disease transmission. The study was conducted in the Gampaha Medical Office of Health (MOH) area of Sri Lanka with the focus of elucidating the microbial diversity within the midgut of Culex quinquefasciatus, a crucial step to support ongoing paratransgenesis efforts. Sampling was performed by utilizing standard mosquito sampling techniques and their midgut homogenates were plated on Plate Count Agar to isolate bacteria, which were then identified through biochemical tests. Subsequently, the most abundant bacterial families were subjected to DNA extraction, PCR amplification, and gene sequencing for species identification. The study revealed the presence of four bacterial families (Staphylococcaceae, Streptococcaceae, Neisseriaceae, and Moraxellaceae) in adult mosquitoes, while larvae harbored an additional family, Micrococcaceae. Interestingly, the relative distribution of midgut bacteria varied significantly among field‐caught larval and adult strains from different study areas (chi‐square = 1.673; P < 0.05), indicating similar bacterial flora across mosquito life stages and geographical locations. Of particular interest is the identification of Lysinibacillus sphaericus, a bacterium with potential for paratransgenesis applications. Given the high mosquito density in the study area, leveraging paratransgenesis for Cx. quinquefasciatus control is recommended. Furthermore, insights into gut microbes could inform the integration of gut microflora from modified strains into existing Sterile Insect Technique (SIT) and Incompatible Insect Technique (IIT) approaches in Sri Lanka. [ABSTRACT FROM AUTHOR]

Lymphatic filariasis (LF) is a crippling and disfiguring parasitic condition. India accounts for 55% of the world's LF burden. The filarial parasite Wuchereria bancrofti is known to cause 99.4% of the cases while, Brugia malayi accounts for 0.6% of the issue occurring mainly in some pockets of Odisha and Kerala states. The Balasore (Baleswar) district of Odisha has been a known focus of B. malayi transmission. We employed molecular xenomonitoring to detect filarial parasite DNA in vectors. In six selected villages, Gravid traps were used to collect Culex mosquitoes and hand catch method using aspirators was followed for collection of mansonioides. A total of 2903 mosquitoes comprising of Cx. quinquefasciatus (n = 2611; 89.94%), Cx. tritaeniorhynchus (n = 100; 3.44%), Mansonia annuliferea (n = 139; 4.78%) and Mansonia uniformis (n = 53; 1.82%) were collected from six endemic villages. The species wise mosquitoes were made into 118 pools, each with a maximum of 25 mosquitoes, dried and transported to the laboratory at VCRC, Puducherry. The mosquito pools were subjected to parasite DNA extraction, followed by Real-time PCR using LDR and HhaI probes to detect W. bancrofti and B. malayi infections, respectively. Seven pools (6.66%) of Cx. quinquefasciatus, showed infection with only W. bancrofti while none of the pools of other mosquito species showed infection with either W. bancrofti or B. malayi. Although the study area is endemic to B. malayi, none of the vectors of B. malayi was found with parasite infection. This study highlights the ongoing transmission of bancroftian filariasis in the study villages of Balasore district of Odisha and its implications for evaluating LF elimination programme. [ABSTRACT FROM AUTHOR]

Effective mosquito population suppression has been repeatedly demonstrated in field trials through the release of male mosquitoes to induce sterile mating with wild females using the incompatible insect technique (IIT), the sterile insect technique (SIT), or their combination. However, upscaling these techniques requires a highly efficient and scalable approach for the sex separation of mass-reared mosquitoes to minimize the unintentional release of females, which can lead to either population replacement or biting nuisance, a major bottleneck up to now. Here, we report the successful development of an automated mosquito pupa sex sorter that can effectively separate large numbers of males from females for population suppression of Aedes aegypti, A. albopictus, and Culex quinquefasciatus. The male production capacity of the automated sex sorter was increased by ~17-fold compared with manual sex separation with the Fay-Morlan sorter and enabled one person to separate 16 million males per week. With ~0.5% female contamination, the produced males exhibited high flight ability and mating performance. The field trial demonstrates that the quality of A. albopictus males produced using the automated sex sorter is suitable for inducing population suppression. These results indicate that the automated sex sorter offers the potential to upscale IIT and SIT against mosquito vectors for disease control. Editor's summary: Several techniques have been developed to fight mosquito-borne diseases, including the release of sterile or incompatible male mosquitoes into the wild to reduce population growth. However, sorting mosquitoes by sex is a laborious process. Gong et al. have now developed an automated mosquito pupa sex sorter, which was tested on three mosquito species and shown to increase the production of males 17-fold when compared with a manual separation process. A field trial in Guangzhou, China showed that the process was capable of producing sufficient incompatible males without reducing their quality, which led to the suppression of wild populations of mosquitoes. —Amos Matsiko [ABSTRACT FROM AUTHOR]

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Oviposition attractants hold the potential attention for monitoring and controlling mosquitoes by enticing them to deposit eggs at specific locations. In this study, the bacterial culture filtrate of Bacillus thuringiensis var. israelensis VCRC B650, previously isolated from clay soil at an agricultural site in U.T of Puducherry, was investigated for the first time. This larvicidal bacterium was assessed for oviposition attractancy against dengue and filarial vectors, namely, gravid females of Aedes aegypti and Culex quinquefasciatus, respectively. The investigation revealed that, at 1:1 dilution of bacterial culture filtrate and water, Cx. quinquefasciatus exhibited significant attraction, with an oviposition activity index (OAI) value of +0.92, surpassing the standard threshold value of +0.30. The OAI of Bti culture filtrate at a 1:1 dilution was also compared with a standard oviposition attractant, p-cresol, at a concentration of 10ppm. It was observed that the Bti culture filtrate demonstrated a significant oviposition attractant effect, with 80 per cent more egg rafts laid, compared to p-cresol at 20 per cent. GC-MS analysis showed that there were 25 compounds present in the Bti culture supernatant, and out of those, only one compound, namely, benzaldehyde, was effective in showing oviposition attraction. [ABSTRACT FROM AUTHOR]

The emergence of antimicrobial resistance (AMR) in pathogens and their spillover into the environment have become a global public health menace. Insects can acquire these pathogens from the environment and would serve as mechanical and biological vectors. The current study assessed the ability of Culex quinquefasciatus mosquitoes to acquire methicillin-resistant Staphylococcus aureus (MRSA) through the exposure of the mosquitoes to the pathogen via rearing water, blood feed, or a feeding membrane under laboratory conditions. In addition, mosquito immatures collected from their habitat in the vicinity of hospitals, veterinary dispensaries, and butcher shops at 15 study sites in Puducherry were screened for MRSA infection. All samples were subjected to the culture-based isolation of S. aureus from the surface and homogenate. The presence of the S. aureus-specific nuc gene and the genes that confer resistance to methicillin (mecA and mecC) were screened using PCR tests. MRSA was not evident either on the external surface or in the homogenate of the mosquitoes emerging from the larvae reared in the MRSA-spiked water or those fed with MRSA through blood or smeared membranes. Furthermore, the presence of MRSA was not evident in any of the field-caught mosquitoes. Hence, we conclude that C. quinquefasciatus mosquitoes are impervious to MRSA colonization. [ABSTRACT FROM AUTHOR]