Search Results (713)

Today’s primary challenges include identifying efficient, affordable, and environmentally sustainable substances to serve as raw materials in industrial, agricultural, and medicinal applications. This study aimed to evaluate the chemical composition and biological properties (namely antioxidant and allelopathic activities) of the methanolic extract derived from the above-ground portions of Artemisia judaica collected in Jazan, Saudi Arabia. GC-MS was used to evaluate the chemical composition of the methanolic extract derived from Artemisia judaica. GC-MS analysis revealed a total of 22 volatile compounds in the extract. The most prominent compounds identified were 2-ethylhexanoic acid, 5-hydroxy-6-(1-hydroxyethyl)-2,7-dimethoxynaphtho-quinone, and piperitone. The extract demonstrated strong antioxidant activity in both the DPPH and ABTS radical scavenging assays, comparable to the standard antioxidant ascorbic acid. The IC₅₀ value for the extract was 31.82 mg/mL in the DPPH assay and 39.93 mg/mL in the ABTS testing. Additionally, the extract exhibited dose-dependent inhibition of seed germination, root growth, and shoot growth of the weed Chenopodium murale in allelopathic bioassays. The most significant suppression was observed in shoot growth with an IC₅₀ value of 45.90 mg/mL, which was lower than the IC₅₀ values for root development and seed germination of C. murale, recorded at 56.16 mg/mL and 88.80 mg/mL, respectively. Furthermore, the findings indicated that methanolic extracts had significant lethal toxic effects on the life cycle of Aedes aegypti. Future research will focus on extracting uncontaminated substances and evaluating the biological effects of each specific constituent. Full article

Background: Arthropod-borne diseases primarily affect tropical and subtropical regions, exhibiting seasonal patterns that peak during hot and rainy months when conditions favor mosquito vector proliferation. Factors such as high temperatures, elevated humidity, rainfall, urbanization, and the abundance of natural and artificial breeding sites influence Aedes vector dynamics. In this context, arboviruses pose significant public health challenges, likely worsened by global warming. In Brazil, Aedes (Stegomyia) aegypti (Linnaeus, 1762) is the primary vector for yellow fever, dengue, chikungunya, and Zika. Aedes (Stegomyia) albopictus (Skuse, 1894) is an important global arbovirus vector and is considered a potential vector in Brazil. Entomological surveillance of these species often uses oviposition traps targeting immature stages. Evaluating studies that use ovitraps to collect Ae. aegypti and Ae. albopictus egg is essential for improving mosquito surveillance strategies. This study systematically reviewed peer-reviewed articles on ovitrap-based surveillance of Aedes mosquitoes in Brazil, published in Portuguese and English from 2012 to 2022. The findings suggest that ovitraps are an effective method for detecting the presence or absence of Ae. aegypti and Ae. albopictus, serving as a reliable proxy for estimating mosquito abundance in Brazilian contexts. Full article

The mosquito Aedes aegypti is the vector responsible for the transmission of important arboviruses such as dengue fever, Chikungunya, Zika virus, and yellow fever. These diseases affect millions of people and exert impacts on healthcare systems throughout the world. Given the increasing resistance to synthetic insecticides, essential oils from plants constitute an ecologically viable alternative for the control of this vector. The aim of the present study was to investigate the larvicidal activity of the essential oil (EO), aqueous extract, rutin, and hydrolate from the leaves of Myrciaria floribunda against Aedes aegypti larvae in the initial L4 stage. The yield of EO was 0.47%. Thirty-seven chemical constituents were identified and quantified using chromatographic methods. The major constituents were (E)-caryophyllene (27.35%), 1,8-cineole (11.25%), β-selinene (4.92%), and α-muurolene (4.92%). In the larvicidal tests, the lethal concentration (LC₅₀) was 201.73 ppm for the essential oil, 15.85% for the aqueous extract, and 22.46 ppm for rutin. The hydrolate had no larvicidal activity. The compounds that exhibited larvicidal activity against Aedes aegypti constitute a promising option for the development of natural formulations to diminish the propagation of this vector. Full article

The Aedes aegypti mosquito, vector of dengue, is a major public health threat in the Caribbean. In Guadeloupe, where dengue outbreaks occur frequently, traditional plant-based remedies are part of the local heritage but remain poorly documented. This study aimed to evaluate the anti-mosquito potential of 38 Guadeloupean plants through an ethnobotanical survey. A semi-structured online questionnaire was conducted over five months, targeting the plant knowledge of residents. Inclusion/exclusion criteria were applied to identify and validate relevant species. Ethnobotanical indices such as Frequency of Citation (FC), Fidelity Level (FL), and Relative Frequency of Citation (RFC) were calculated. Out of the 38 surveyed plants, 22 were confirmed for their traditional anti-mosquito uses. The most cited species included Cymbopogon citratus (93.3%), Artocarpus altilis (25%), and Pimenta racemosa (18.3%). Comparative analysis with existing literature showed that 12 of these plants had not been previously reported for vector control. This highlights the value of ethnobotanical approaches for discovering alternative, eco-friendly vector control options and the importance of preserving traditional knowledge. The study reveals both the high potential of Guadeloupean flora and the risk of cultural erosion, supporting further research into the bioactive compounds of the most cited species. Full article

The present study evaluated the larvicidal and pupicidal activities of pure and mixed monoterpene formulations—eucalyptol, geranial, trans-anethole, and trans-cinnamaldehyde—against Aedes aegypti and compared them with 1% (w/w) temephos. Safety bioassays of all formulations on non-target species confirmed their safety. The combined mixture of eucalyptol + trans-anethole at 400 µg/mL exhibited stronger larvicidal activity, with an LC₅₀ of 176 µg/mL, while the combination of trans-anethole + geranial at 400 µg/mL exhibited stronger pupicidal activity with an LC₅₀ of 167 µg/mL. Both formulations were more effective than a 1% temephos. All the mixture formulations were more strongly synergistic compared to pure formulations, with an increased mortality value (IMV) of 25% to 95%. External morphological aberrations observed at death included swelling of the respiratory system. Importantly, all the formulations were safe for two non-target species: guppies (Poecilia reticulata) and honeybees (Apis mellifera). The combination formulations are strong larvicides and pupicides for controlling Ae. Aegypti, which will help reduce the spread of viruses carried by this vector. Full article

Dengue virus serotypes 1-4 (DENV1-4) have spread through tropical and subtropical countries, causing endemic and epidemic diseases. Recently, a novel field approach using the Wolbachia symbiont was proposed to suppress DENV transmission via the mosquito vectors Aedes aegypti and Aedes albopictus. Previously, we showed that a Wolbachia strain, wMelPop, suppresses DENV2 replication in the C6/36 albopictus cell line, with the mutant DENV2 appearing and replacing the wild type DENV2. In this study, we expanded the analysis to include replications of all DENV serotypes 1-4, effects of wAu Wolbachia in C6/36 cells, and wMelPop-influences on the Aag2 aegypti cell line. It was revealed that both wAu and wMelPop reduce all DENV infectious titers without dominant appearances of the mutant viruses, despite varied effects on the viral copy numbers. The host transcriptomic profiles by RNA-seq were also variously altered by wAu and wMelPop (ranging from 10 to 30%, Log₂FC > 2 or <−2, p < 0.05). Those transcripts were not further altered by DENV infection. In contrast, abundant transcriptomic alterations by DENV infection in naïve C6/36 and Aag2 cells were blocked by either wAu or wMelPop. These results indicate that Wolbachia prevents host cellular transcriptomic alterations which are induced by DENV infection, affecting the cellular homeostasis necessary for DENV replication. Full article

Olfaction has been extensively studied in the yellow fever mosquito, Aedes aegypti. This species uses its sense of smell to find blood hosts and other resources, contributing to its impact as a vector for human pathogens. Two major families of protein-coding genes, the odorant receptors (Ors) and the ionotropic receptors (Irs), provide the mosquito with sensitivities to distinct classes of volatile compounds in the antennae. Individual tuning receptors in both families require co-receptors for functionality: Orco for all Ors, and Ir8a for many Irs, especially ones that are involved in carboxylic acid detection. In Drosophila melanogaster, disruptions of Orco or Ir8a impair receptor function, tuning receptor expression, and membrane localization, leading to general anosmia. We reasoned that Orco and Ir8a might also be important for coordinated chemosensory receptor expression in the antennal sensory neurons of Ae. aegypti. To test this, we performed RNAseq and differential expression analysis in wildtype versus Orco^−/− and Ir8a^−/− mutant adult female antennae. Our analyses revealed Or and Ir tuning receptors are broadly under-expressed in Orco^−/− mutants, while a subset of tuning Irs are under-expressed in Ir8a mutants. Other chemosensory and non-chemosensory genes are also dysregulated in these mutants. Furthermore, we identify differentially expressed transcription factors including homologs of the Drosophila melanogaster Mip120 gene. These data suggest a previously unknown pleiotropic role for the Orco and Ir8a co-receptors in the coordination of expression of chemosensory receptors within the antennae of Ae. aegypti by participating in a feedback loop involving amos and members of the MMB/dREAM complex. Full article

Mosquitoes of the Aedes and Culex genera are primary vectors of arboviruses such as the dengue, Zika, chikungunya (CHIKV), Oropouche, and West Nile viruses, causing millions of infections annually. Standard virus detection in mosquitoes requires capturing, transporting, and processing samples with a cold chain to preserve RNA, which is challenging in resource-limited areas. FTA cards preserve viral RNA at room temperature and have been used to collect mosquito saliva, a key sample for assessing transmission. However, most FTA-based traps require electricity or CO₂, limiting use in low-resource settings. This study adapted and evaluated the BR-ArboTrap, a low-cost trap derived from an oviposition trap, integrating a sugar-based attractant with FTA cards to collect mosquito saliva, without electricity or refrigeration. Aedes aegypti exposed to CHIKV were used in three experiments to evaluate: (i) RNA preservation under different conditions, (ii) the minimum number of positive mosquitoes for detection, and (iii) RNA amounts on FTA versus blood. RT-qPCR detected CHIKV RNA in 90% of FTA cards and 96% of exposed mosquitoes. RNA remained stable under varying conditions, with no significant difference compared to blood. BR-ArboTrap is an effective, affordable, and field-ready tool to enhance arbovirus surveillance in remote and low-resource areas. Full article

The rapid global expansion of Aedes aegypti-borne diseases such as dengue, chikungunya, and Zika has positioned this mosquito as a key target for vector control programs. These programs rely heavily on insecticide use, leading to the widespread emergence of insecticide resistance. Understanding the molecular basis of resistance is essential for developing effective management strategies. In this study, we employed a whole-transcriptome (RNA-seq) approach to analyze gene expression in three Ae. aegypti populations from Mexico that underwent four generations of laboratory selection with deltamethrin. Several cytochrome P450 genes (CYP6AG4, CYP6M5, CYP307A1) and a chitin-binding peritrophin-like gene (Ae-Aper50) were significantly overexpressed following selection, supporting roles for both detoxification and midgut protection. We also observed a consistent downregulation of cuticular protein genes in deltamethrin-selected groups relative to the baseline populations, suggesting their involvement in baseline tolerance rather than induced resistance. Additionally, the overexpression of immune- and stress-related genes, including the RNA helicase MOV-10, indicates that insecticide selection may trigger broader physiological responses. These findings highlight complex, multi-pathway transcriptomic changes associated with resistance development in Ae. aegypti. Full article

Serratia plymuthica, isolated from the midgut of Aedes aegypti, displays remarkable resilience to hemin, a toxic hemoglobin byproduct generated during blood digestion. This study explores its proteomic adaptations under oxidative stress induced by 5 mM hemin, mimicking midgut conditions. Growth assays demonstrated that S. plymuthica tolerated hemin concentrations ranging from 5 µM to 1 mM, reaching the stationary phase within approximately 10 h. Colonies exhibited morphological changes—darkened peripheries and translucent halos—suggesting heme accumulation and detoxification. Label-free quantitative proteomics identified 436 proteins, among which 28 were significantly upregulated—including universal stress proteins (USPs), ABC transporters, and flavodoxin—while 54 were downregulated, including superoxide dismutase and several ribosomal proteins. Upregulated proteins were associated with antioxidant defense, heme transport, and redox regulation, whereas downregulated proteins suggested metabolic reprogramming to conserve energy under stress. Functional enrichment analysis revealed significant alterations in transmembrane transport, oxidative stress response, and central metabolism. These findings suggest that S. plymuthica contributes to redox homeostasis in the mosquito gut by mitigating reactive oxygen species (ROS) and detoxifying excess heme, supporting its role as a beneficial symbiont. The observed stress tolerance mechanisms may influence mosquito physiology and vector competence, offering novel insights into mosquito–microbiota interactions and potential microbiota-based strategies for vector control. Full article

In Tanzania, dengue outbreaks have occurred almost annually over the past decade, with each new outbreak becoming more severe. This study investigated the prevalence of dengue virus (DENV) serotypes in the wild Aedes aegypti and their blood sources to determine human exposure risk in Dar es Salaam, Tanzania. A two-year longitudinal survey was conducted in the Ilala, Kinondoni, and Temeke districts of Dar es Salaam to sample Ae. aegypti mosquitoes using Biogents Sentinel trap (BGS), Prokopack aspiration, and Gravid Aedes trap (GAT). Collected mosquitoes were pooled in groups of 10 and tested for DENV1–4 serotypes using reverse transcription polymerase chain reaction (RT-qPCR). Blood meal sources were identified using an enzyme-linked immunosorbent assay (ELISA). Of 854 tested pools, only DENV-2 was detected and was found in all three districts: Temeke (3/371 pools), Ilala (1/206 pools), and Kinondoni (1/277 pools). Blood meal analysis showed a strong preference for humans (81%) as well as for mixed blood meals that contained human blood and other hosts (17%). Out of 354 collected hosts seeking Ae. aegypti, 78.5% were captured outdoors and 21.5% indoors. This study confirms the circulation of DENV-2 in Ae. aegypti populations, indicating a potential dengue outbreak risk in Tanzania. This study also demonstrates that xenomonitoring may be feasible in this setting. The mosquitoes’ strong preference for human hosts and predominance in outdoor settings pose challenges for dengue control efforts. Full article

The Aedes aegypti mosquito is a vector for several arboviral diseases, posing a significant threat to human populations and exacerbating health disparities. Puerto Rico is a subtropical region where A. aegypti mosquitoes circulate all the year promoting the transmission of arboviruses. A cross-sectional study in the municipality of Ponce, Puerto Rico was conducted to determine the prevalence of arbovirus in A. aegypti mosquitoes and community members, and the impact that sociodemographic and environmental factors on the presence of arbovirus in the community. Our results indicate that more than a third of the population has long-term antibodies (IgG) against chikungunya and the Mayaro virus (56% and 17%, respectively). In addition, more than two-thirds of the population have long-term antibodies (IgG) against dengue and Zika virus (96.0% and 77%, respectively). Dengue virus 1 (DENV-1) was only detected in mosquitoes from urban areas. The practice of storing water in containers uncovered and living near a river increased the odds of having arbovirus in the community (OR = 3.5, 95% CI = 1.8–10.6) (p < 0.05) and (OR = 1.6, 95% CI = 1.2–3.7). Furthermore, lower income was a social determinant associated with being at risk of arboviral disease in the communities (OR = 2.9, 95% CI = 1.4–8.5) (p < 0.05). It is recommended that public health activities be implemented, including education workshops on prevention and health promotion and health services such as vector control, to prevent arboviral diseases in communities. Full article

Ecuador, a tropical country with frequent dengue outbreaks, including a surge from 16,017 cases in 2022 to 61,329 in 2024, was the focus of this study. The study was conducted in Borbon, a semi-urban rural town in the Esmeraldas province. Genomic analysis, alongside entomo-virological surveillance, provides valuable insights into DENV-2 genotypes. Five pools of female Aedes aegypti mosquitoes from Borbon tested positive for DENV serotype 2 through RT-qPCR. One positive pool (CT = 16.13) was sequenced using Illumina MiSeq, and genotyping was conducted via the Dengue Typing Tool and Maximum Likelihood phylogenetic tree. The genotype assigned was III Southern Asian-American. Comparison with other genomes revealed genetic similarity to a human dengue genome sequenced in 2021, also from Esmeraldas, clustering with genomes reported across the Americas, particularly from Colombia and Venezuela. This study enhances our understanding of dengue virus epidemiology in rural areas, emphasizing the critical role of clinical case surveillance and vector monitoring in guiding evidence-based interventions. Full article

Aedes aegypti, the main urban vector of dengue fever, represents a growing public health problem in Nouakchott, the capital of Mauritania. Identifying the factors influencing the distribution and productivity of its breeding sites is essential for the development of effective control strategies. From May 2023 to April 2024, physico-chemical characteristics were recorded and mosquito larvae were collected, using a standard dipping method, from 60 water collections each month during the dry season and twice a month during the rainy season, totaling 294 observations. The larval positivity of water collections and larval abundance of breeding sites over the time were modeled using a random-effect logistic regression model and a negative binomial regression model, respectively. The depth, distance from habitat, type of water collection and exposure to sunlight were statistically significant and independently associated with water collection positivity for Ae. aegypti larvae (aOR = 5.18, 95%CI [1.66–16.18], p-value = 0.005; aOR = 0.00, 95%CI [0.00–0.02], p-value < 0.001; aOR = 252.88, 95%CI [4.05–15,786.84], p-value = 0.009 and aOR = 0.04, 95%CI [0.01–0.26], p-value < 0.001, respectively). Aedes aegypti larval habitats were mainly artificial (90%), temporary (n = 217 observations), close to dwellings (n = 114) and shaded (n = 96). Plastic water tanks (n = 17, 48.6%), wells (n = 6, 17.1%) and barrels (n = 4, 11.4%) were the most common breeding sites. Larval abundance was negatively associated with containers of increasing pH and surface area (aOR = 0.50, 95%CI [0.33–0.75] p-value = 0.001 and aOR = 0.48, 95%CI [0.27–0.87], p-value = 0.016, respectively). As Ae. aegypti mosquitoes are multi-resistant to adult insecticides and dengue has become endemo-epidemic since 2014, vector control should give the priority to the physical removal or treatment of shaded, peridomestic containers—particularly plastic water tanks and barrels—and consider the use of biological larvicides to target breeding sites with low pH and small surface areas. Full article

During the last 20 years, there has been increasing concern about inefficient vector control efforts due to insecticide resistance. A common mechanism causing insecticide resistance is mutational changes in the voltage-gated sodium channel, deemed knockdown resistance (kdr), resulting from continued pyrethroid application. Although closely related, there have been documented kdr differences and frequencies between Aedes aegypti and Aedes albopictus. Individual Ae. aegypti and Ae. albopictus from five counties in Texas, USA were tested using four single nucleotide polymorphisms genotyping assays to assess the kdr (F1534C, V1016I, V410L, and S989P) differences between the two species. Each mutation was analyzed independently by calculating frequencies and analyzing the difference using a Wilcox Rank Sum test. Significant differences were observed between Ae. aegypti and Ae. albopictus when comparing F1534C and V410L (p-value < 0.0001). Knockdown resistant mutation V1016I was not different between the two species. Individuals from both species had di-locus mutations, and individuals from Ae. aegypti had tri-locus mutations detected in combinations that have been reported to influence insecticide resistance. Given our findings, one can speculate that populations of both species are resistant to pyrethroids, thus likely limiting the success of control methods. Full article