Search Results (487)

Identifying conserved RNAi targets that remain effective across mosquito species and resistance backgrounds is important for developing broadly applicable mosquito control tools. Here, an engineered Escherichia coli HT115-L4440 system was used to produce β-tubulin double-stranded RNA (dsRNA), and its larvicidal activity was evaluated in susceptible and pyrethroid-resistant strains of Culex quinquefasciatus and Aedes albopictus. Recombinant bacteria produced species-specific β-tubulin dsRNA fragments of approximately 360 bp. Immersion treatment caused high larval mortality in both species. In Cx. quinquefasciatus, mortality reached 85.00% and 89.00% in susceptible and resistant strains, respectively, compared with 8.00% and 10.00% in controls, while β-tubulin transcript abundance showed maximum reductions of 571-fold and 333-fold, respectively. In Ae. albopictus, mortality reached 91.00% and 82.00% in susceptible and resistant strains, compared with 9% and 8% in controls, with maximum reductions in β-tubulin expression of 157-fold and 337-fold, respectively. These comparable effects suggest that β-tubulin dsRNA is not compromised by conventional pyrethroid-resistance mechanisms. Transcriptomic and proteomic analyses showed that β-tubulin knockdown disrupted key cellular processes, including cytoskeletal regulation, metabolism, protein synthesis, intracellular transport, detoxification, oxidative stress, DNA replication, and autophagy. Overall, engineered bacteria-derived β-tubulin dsRNA induced consistent gene silencing and larval mortality in both susceptible and resistant mosquito larvae, supporting β-tubulin as a conserved candidate RNAi target for mosquito control. Full article

The long-term efficacy of vector control programs is seriously hampered by the evolution of insecticide resistance. In this scenario, assessing the distribution, frequency, and drivers of resistance spread is crucial to planning effective control programs. Here, we addressed these issues in the mosquito Culex pipiens, focusing on the Emilia-Romagna region (Italy), a known hotspot of diflubenzuron (DFB) resistance. First, Cx. pipiens larvae were screened for point mutations conferring DFB resistance to capture the distribution and frequency of resistance-associated alleles across the region. To this end, a fragment of the chitin synthase 1 gene spanning the mutated site was sequenced. Then, by using population genomics, we investigated the vector population structure in this area. Our findings revealed that resistance-associated alleles maintain a focal geographic distribution in the region, with higher mutation frequencies in the central-eastern than in the western provinces. Also, we observed that the populations of Cx. pipiens are a highly homogeneous gene pool and can be interconnected across the region, highlighting the risk of resistance alleles spread across Emilia-Romagna. Overall, this study stresses the importance of systematically surveying resistance-associated alleles and their integration with population genomic data to gain relevant information for resistance management. Full article

Background/Objectives: Mosquito-borne viruses cause substantial global morbidity and mortality. Mosquito saliva, secreted during biting, facilitates blood feeding and can enhance virus infection. Here, we evaluated whether combining virus-specific antigens with mosquito salivary protein-derived peptides improves protection in Zika virus (ZIKV) and chikungunya virus (CHIKV) mouse models. Methods: Peptides from Aedes and Culex salivary proteins were selected based on conservation, predicted T-cell reactivity, and cellular and humoral immunogenicity in mice. Mice were immunised subcutaneously with a prime and boost two weeks apart using adjuvanted salivary peptides (SAL), commercial ZIKV- or CHIKV-like particles (VLPs), or salivary peptides combined with the relevant VLPs. Vaccine doses contained 0.5 µg VLPs and/or 10 nmol of each salivary peptide, formulated with Montanide ISA-51; when combined, VLPs and SAL were administered on opposite flanks. Two weeks after boosting, mice were challenged with ZIKV or CHIKV plus Aedes aegypti saliva. Challenge teams were blinded to group allocation until data analyses were complete. Results: SAL enhanced the protective effect of VLP vaccination compared with VLPs alone. In the CHIKV model, CHIKV VLP + SAL prevented joint swelling and reduced infectious virus in the inoculated ankle and viral RNA in the contralateral ankle. In the ZIKV model, ZIKV VLP + SAL reduced viral RNA in skin and brain tissue and improved survival. Conclusions: Mosquito salivary peptide antigens improved the protective efficacy of VLP vaccines against ZIKV and CHIKV in mouse models. Salivary antigens may provide a complementary vaccine component for multiple arboviruses transmitted by Aedes and Culex mosquitoes. Full article

Japanese encephalitis virus (JEV) is a zoonotic pathogen transmitted primarily by Culex mosquitoes and causes severe neurological diseases in humans and animals. The main endemic areas are the Western Pacific and Southeast Asia, and its geographical distribution has expanded in recent years. The development of a diagnosis for orthoflavivirus infections is hampered by two main problems: the short duration of viremia, resulting in a narrow detection window, and severe cross-reactivity. NS1, a secreted nonstructural protein of orthoflavivirus, holds promise as a new target for overcoming these limitations. In this study, we established a highly specific and sensitive capture ELISA for the JEV NS1 protein. First, the JEV NS1 protein was successfully expressed in mammalian cells and purified using affinity chromatography. Seven mAbs recognizing JEV NS1 were generated, and the mAb 20B6 exhibited the strongest binding affinity. Based on 20B6, a capture ELISA was developed with an optimal coating concentration of 3 μg/mL and an optimal detection antibody working concentration of 0.432 μg/mL. No cross-reactivity was observed with other orthoflaviviruses (including WNV, KUNV, USUV, MVEV, SLEV, and ZIKV) or common porcine viruses. The method could effectively detect NS1 protein in cell culture medium, cell lysates, mouse tissues, and porcine serum samples from JEV-infected subjects. This study provides a solid foundation that may be further developed into an efficient and specific tool for epidemiological surveillance of Japanese encephalitis. Full article

Phytotelmata are natural water-holding microhabitats that support diverse aquatic communities, including immature mosquitoes. We analyzed the diversity, composition, and interaction network structure of Culicidae associated with two bromeliad species, Aechmea distichantha and Vriesea friburgensis, in two localities of the Yungas ecoregion in northwestern Argentina: La Florida Provincial Reserve (LFPR) (Tucumán) and Isla de Cañas (Salta). Immature mosquitoes were sampled during 2017–2018, and community structure was evaluated using Hill numbers, nonparametric richness estimators, bipartite network analysis, and canonical correspondence analysis (CCA). A total of 12 mosquito species were identified, with richness ranging from 5 to 9 species depending on bromeliad species and locality, with the highest richness recorded in V. friburgensis in LFPR. Sampling completeness ranged from 96.8% to 100%. Bipartite network analysis showed moderate connectance (0.50), low modularity (Q = 0.188), intermediate nestedness (NODF = 46.94), and low global specialization (H2′ = 0.273), suggesting a relatively generalized interaction structure. Culex coronator and Cx. imitator dominated the assemblage, while other species exhibited more restricted associations. The CCA indicated that species composition was mainly associated with bromeliad height above ground, internal water temperature, sediment, and pH. These results highlight the importance of microhabitat heterogeneity in structuring mosquito assemblages in Neotropical phytotelmata. Full article

Rift Valley fever (RVF) is a climate-sensitive mosquito-borne zoonosis long regarded as a rural, pastoral disease, yet accelerating tropical urbanization and intensifying climate variability may be reshaping its epidemiology at the urban–peri-urban interface. This narrative review examines how global climate change and urban-specific climatic conditions jointly shape RVF virus (RVFV) vector habitats, transmission, and burden in tropical and subtropical cities, synthesizing 51 of 412 English-language records identified by a structured, non-systematic search of PubMed, Scopus, Web of Science, and Google Scholar (2009–2026) and selected for relevance to urban and peri-urban RVF. This research draws on human, livestock, and vector evidence from Sub-Saharan Africa, the Arabian Peninsula, and Indian Ocean islands across epidemic and inter-epidemic periods. The synthesis indicates that impervious surfaces, poor drainage, and open water storage can recreate the water-retaining function of rural dambos, sustaining a year-round larval habitat, and that Culex quinquefasciatus dominance together with peri-urban cattle may form an amplification bridge to humans. Direct evidence remains scarce, anchored by a single peri-urban serosurvey and limited urban slaughterhouse entomology. Critical gaps include urban primary-vector ecology, infection-rate data, urban-heat effects, city-specific exposure studies, and coupled climate–urban burden models. We conclude that RVF is a plausible emerging urban threat warranting proactive inter-epidemic surveillance and integration of RVF into urban planning and One Health systems. Full article

Mosquitoes are significant public health insects responsible for numerous vector-borne diseases. Injudicious chemical use has developed metabolic and genetic resistance in mosquitoes. This study evaluated the repellent efficacy of five essential oils (EOs) from local plants [Mentha spicata I, Ruta tuberculata, Mentha spicata II, Lavandula latifolia, and L. stoechas]. M. spicata I and R. tuberculata EOs were extracted using Clavenger hydrodistillation. Simultaneously, the remaining EOs were obtained through a local extraction distillation unit. Chemical composition was identified using GC-MS. Repellency was assessed using the arm-in-cage method, by rearing Culex pipiens s.l. and Aedes albopictus in the laboratory. Additionally, mixtures containing 15% DEET, 15% IR3535, 5% vanillin, and 10% M. spicata I EO were tested. Both mosquito species were clearly repelled by all EOs. M. spicata I was most potent at 10% concentration. The complete protection time (CPT) at 10% M. spicata I EO was increased using blended mixtures containing 15% DEET, 15% IR35353, or 5% vanillin. Regional variations in M. spicata EOs were detected. This study may serve as a foundation for cosmetic manufacturers and pest control products. Developing botanical and hybrid (natural and synthetic) formulations could provide strong protection against insect bites, particularly from disease-vector mosquitoes, helping to prevent vector-borne diseases. Full article

The widespread circulation of the Anopheles vector is observed during the rainy season and clearly decreases during the dry season, when only a few mosquitoes are able to survive. This study aimed to identify the major species sustaining continued malaria transmission across seasons. This cross-sectional study was conducted in a malaria-endemic area. Mosquitoes were captured in Faladie using pyrethroid spray catches during rainy and dry seasons. The collected mosquitoes were identified using morphological keys, combined with molecular techniques such as PCR-RFLP (IGS regions) for Anopheles (An.) gambiae s.l. identification. Plasmodium spp. positivity in each mosquito was characterized by qPCR using parasite 18 S genes. A total of 1082 and 1705 mosquitoes were captured inside the same houses in the rainy and dry seasons, respectively. In the rainy season, 454 (41.9%) were Anopheles, 624 (57.7%) Culex and 4 (0.4%) Aedes. During the dry season, 65 (3.81%) mosquitoes were Anopheles, while 1,640 (96.19%) were Culex. Morphologically, the anopheline population consisted of 100% An. gambiae s.l. The Anopheles species diversity in the rainy season comprised the sister taxa, An. gambiae s.s. and An. Coluzzii, followed by an An. gambiae/An. coluzzii hybrid and An. arabiensis. However, An. coluzzii was found as the only vector across the rainy and dry seasons that sustained malaria transmission. Plasmodium falciparum infection rates were 9.7% and 1.7%, respectively, for the rainy and dry seasons. An. coluzzii species can survive both the dry and the rainy seasons and sustain malaria through cross-seasonal transmission. This highlights the importance of tackling An. coluzzii species and residual malaria transmission to eradicate the disease in endemic areas. Full article

The chikungunya virus (CHIKV) is an emerging alphavirus transmitted primarily by Aedes mosquitoes. This narrative review synthesised evidence from 56 mosquito-based records (34 field surveillance records and 22 laboratory vector competence records) published from January 2020 to June 2026. Aedes aegypti was the most frequently detected species, confirmed as CHIKV-positive in 22 of the 29 field studies that examined it, followed by Aedes albopictus (positive in nine of 12). Both species demonstrated consistent laboratory competence. Descriptive laboratory analysis showed mean infection, dissemination, and transmission values of approximately 76%, 77%, and 37% for Ae. aegypti, and 79%, 80%, and 47% for Ae. albopictus, respectively; these values are descriptive summaries across heterogeneous laboratory protocols and inconsistently reported genotypes. East/Central/South African–Indian Ocean Lineage of the chikungunya virus (ECSA-IOL) showed the highest mean transmission efficiency among genotype groups. In addition, CHIKV RNA was also detected in Culex quinquefasciatus, Psorophora spp., Wyeomyia spp., and other culicids in field studies, but laboratory evidence does not support these species as confirmed competent vectors. Other Aedes species, including Aedes vittatus, Aedes polynesiensis, Aedes koreicus, and Aedes japonicus, may have regional relevance but require further validation. Key evidence gaps include incomplete genotype reporting, limited virus isolation from positive mosquito pools, and inconsistent transmission metrics. Future preparedness for CHIKV emergence and spread requires integrated surveillance combining field detection, virus isolation, genomic sequencing, and standardised vector competence assays within an integrated surveillance framework. Full article

West Nile virus (WNV) is a mosquito-borne pathogen of escalating epidemiological importance and a growing global health concern, driven by the climate-associated expansion of its Culex mosquito vectors. Although WNV is an extensively studied flavivirus, most host–pathogen interaction studies focus on static and structural aspects rather than dynamic and functional ones. Delineating phosphorylation-mediated interactions between WNV proteins and human kinases bridges a critical gap by providing important insight into the molecular mechanisms underlying infection. In this study, we investigated potential phosphorylation-mediated interactions between WNV proteins and human kinases using an integrative computational framework combining motif prediction, phosphoproteomic data analysis and structural docking. Key interactions were predicted between viral proteins and regulatory kinases within the AKT-ERK pathway and the AMPK-mediated autophagy, including major network kinases such as RAF1, IKBKB, and ULK1. In addition, experimentally validated phosphorylation sites in viral proteins were found to be associated with multiple candidate host kinases, including MAP2K7 and MAP2K9, suggesting complex regulatory networks. Integration with phosphoproteomic datasets supported the relevance of multiple predicted kinases, including those associated with antiviral responses and translational regulation. Protein–protein docking demonstrated stable, energetically favorable interactions between selected host kinases and viral proteins, particularly the viral polymerase (NS5), helicase (NS3), and NS1. The findings of this study establish a framework for future research on the development of host-directed antiviral strategies. Full article

Assessing mosquito vector competence for emerging arboviruses, including the underlying determinants of infection, is a foundational line of investigation towards understanding arbovirus transmission dynamics and vector–virus interactions. We developed a novel quantitative immune gene array that measures the relative expression of 22 immune genes with functional representation across five major immune pathways using quantitative reverse-transcriptase polymerase chain reaction. Homologous primers were developed for Culex tarsalis, Cx. quinquefasciatus, and Ae. aegypti mosquitoes. As an initial pilot test for this array, Cx. tarsalis and Ae. aegypti mosquitoes were orally challenged with Rift Valley fever virus (RVFV) MP12 strain. Midguts, legs/wings, and salivary glands were harvested at 3 and 7 days post-challenge. Differential gene expression was measured against Rpl32 as a housekeeping gene. This assay was sensitive enough to generate results for single mosquito midgut and salivary gland tissues, providing an initial snapshot of the types of gene expression patterns that can be observed for two mosquito species infected with MP12. This new tool will be broadly applicable for assessing mosquito immune profiles for arbovirus infection across major immune genes in five key pathways, as well as generating comparable results across mosquito and arbovirus systems. Full article

Mosquito control programs rely on larvicides such as S-methoprene to suppress vector populations and prevent mosquito-borne diseases including West Nile virus (WNV). Resistance surveillance is essential for maintaining the long-term effectiveness of larvicide active ingredients and is typically conducted using cup bioassays to evaluate larval susceptibility. Disposable Styrofoam cups are commonly used for these assays because they minimize adsorption of S-methoprene under standard testing conditions. However, recent restrictions on expanded polystyrene products in California necessitated the identification and evaluation of suitable replacement cup materials for larval resistance bioassays. Four alternative cup materials, high-density polyethylene (HDPE), polyethylene terephthalate (PET), polypropylene (PP), and paper cups, were compared to Styrofoam cups. Cup bioassays were conducted using a laboratory colony of Culex quinquefasciatus exposed to S-methoprene concentrations of 1–40 ppb. Emergence inhibition data were analyzed using probit regression to estimate the concentrations causing 50% and 90% emergence inhibition (LC₅₀ and LC₉₀, respectively) for each cup type. Cup material significantly affected concentration-response relationships. HDPE and paper cups produced significantly higher LC₅₀ and LC₉₀ estimates than Styrofoam, whereas PET and PP produced responses more comparable to the Styrofoam reference. Concentration-response slopes were similar among cup materials, indicating that cup material primarily shifted the concentration required to achieve a given level of emergence inhibition. These findings demonstrate that cup material can significantly influence estimated S-methoprene LC values. Replacement assay cups should therefore be validated before implementation in larval resistance monitoring programs. Full article

In Singapore, indoor space spraying, such as ultra-low-volume (ULV) treatment, is used to control adult mosquitoes during vector-borne disease outbreaks. This study assessed the efficacy of Mirakn^® GX, a pyrethroid-based insecticide formulation combining d,d-trans-cyphenothrin with desiccated carbon dioxide as a propellant. The implications of these findings for operational use will be discussed. Mirakn^® GX was evaluated against confined field and laboratory strains of Aedes aegypti, Ae. albopictus and Culex quinquefasciatus under semi-field conditions, following World Health Organization (WHO) guidelines. This study was conducted within an occupied residential apartment unit. An additional evaluation focusing on Ae. aegypti, designed to mimic operational practice, was performed using a reduced exposure duration of 10 min. At an application rate of 1 g/m³ with 60 min exposure, 100% knockdown and 99.79–100% mortality were observed across all three mosquito species. A shortened 10 min exposure also resulted in complete knockdown and mortality in both laboratory and field strains of Ae. aegypti, supporting operational feasibility. Under semi-field conditions, the insecticide formulation showed good penetration into enclosed spaces, indicating its potential use for scenarios where timely management of indoor adult mosquitoes is required, including during outbreaks to kill infected mosquitoes. Full article

Background/Objectives: Mosquitoes, including Culex quinquefasciatus and Aedes aegypti, are important vectors of dengue fever, Zika virus, West Nile virus, Japanese encephalitis virus, Eastern equine encephalitis virus, etc. Biological control has always been urgent in mosquito prevention due to resistance developing to synthetic insecticides and environmental toxicity by insecticides. Methods: The leaf essential oil of Mosla. chinensis was isolated, and major components were identified via GC-MS, followed by olfactory behavior assays to evaluate its repellent activity against C. quinquefasciatus. Additionally, the odorant-binding protein 1 and odorant-binding protein 2 (CquiOBP1-2) genes were prokaryotically expressed, and their fluorescence competitive binding activities with the active components of essential oils were examined. Results: The bioassays indicated this essential oil greatly repels C. quinquefasciatus, which will significantly protect people against vector-borne diseases. In the fluorescence competitive binding experiments, the CquiOBP1-2 proteins exhibit great binding capacities to volatile components, including Citronellal, Citronellol, Geraniol, Limonene and Isopulegol. Furthermore, the behavioral experimental results also indicate that the mixture of these five ligand compounds has an obvious repellent effect on mosquitoes, highlighting that they may be applied as potential mosquito repellent agents. Moreover, molecular docking and site-directed mutation analysis further confirm Phe123 and Gln77 are both key amino acid residues of CquiOBP1-2 proteins involved in the olfactory recognition of repellent ligand compounds from M. chinensis essential oil. Conclusions: The behavioral experimental verification and the exploration of olfactory molecular mechanisms are helpful to promote the biological control of plant essential oils in mosquito pests. Full article

Mosquito-borne diseases pose a significant public health concern globally; however, data on mosquito population dynamics in Taipei, Taiwan are limited and outdated. Updated information on species composition and seasonal abundance is crucial for enhancing vector surveillance and informing effective control strategies. In this study, to investigate the seasonal dynamics of mosquito populations in Taipei, Taiwan, adult females were collected biweekly from June 2023 to May 2025 using CDC light traps baited with ultraviolet light and dry ice. Species identification was performed based on morphological characteristics, and morphologically challenging Culex mosquito species were further confirmed using cytochrome c oxidase I barcoding. Mosquito surveillance from June 2023 to May 2025 yielded 1926 females representing 31 species. Of these, Culex quinquefasciatus, Culex pipiens molestus, Aedes albopictus, and Culex tritaeniorhynchus accounted for over 90% of all specimens. These dominant species exhibited distinct seasonal patterns: Cx. quinquefasciatus occurred year-round, Cx. pipiens molestus predominated during winter and spring, while Ae. albopictus and Cx. tritaeniorhynchus populations peaked in summer. Furthermore, spatial heterogeneity in both mosquito abundance and species composition was noted among the study sites. Monitoring the composition and seasonal dynamics of mosquito species is essential for understanding the epidemiology of mosquito-borne pathogens. These insights can inform more effective and targeted vector control strategies for reducing disease transmission. Such ecological insights can also support One Health approaches by linking human, animal, and environmental factors that influence the transmission of mosquito-borne diseases. Full article