Search Results (107)

Dengue fever remains a major mosquito–borne disease worldwide, with over 400 million infections annually and a high risk of severe complications such as dengue hemorrhagic fever. The disease is prevalent in tropical and subtropical regions, where population density and limited vector control accelerate transmission, making early and reliable diagnosis essential for outbreak prevention and disease management. Conventional diagnostic methods, including virus isolation, reverse transcription polymerase chain reaction (RT–PCR), enzyme–linked immunosorbent assays (ELISA), and serological testing, are accurate but often constrained by high cost, labor–intensive procedures, centralized laboratory requirements, and delayed turnaround times. This review examines current dengue diagnostic technologies by outlining their working principles, performance characteristics, and practical limitations, with emphasis on key target analytes such as viral RNA; nonstructural protein 1 (NS1), including DENV–2 NS1; and host antibodies. Diagnostic approaches across commonly used biofluids, including whole blood, serum, plasma, and urine, are discussed. Recent advances in biosensing technologies are reviewed, including optical, electrochemical, microwave, microfluidic, and CRISPR–based platforms, along with the integration of artificial intelligence for data analysis and diagnostic enhancement. Overall, this review highlights the need for accurate, scalable, and field–deployable diagnostic solutions to support early dengue detection and reduce the global disease burden. Full article

(1) Background: The Asian bush mosquito Aedes japonicus is an invasive species in Europe, including Poland. Given its laboratory-confirmed competence for West Nile virus (WNV) transmission and its detection as a WNV vector in field-collected mosquitoes, this study investigated whether Polish Aedes japonicus harbor WNV and aimed to update knowledge on its distribution in Poland. (2) Methods: In September 2024, 137 adult Aedes japonicus were collected from three suburban sites in Poland (Kielce, Mikołów, Kraków). Specimens were screened for WNV using RT-PCR and rRT-PCR. Additionally, unpublished records of Aedes japonicus were compiled to update the species’ distribution. (3) Results: No WNV genetic material was detected in field-collected mosquitoes in Poland. By 2025, Aedes japonicus had been recorded in half of Polish voivodeships, with most observations in Małopolskie, Śląskie, and Łódzkie. The largest adult populations occurred in Kielce. Ecological traits in Poland matched European and US data, including larval development in artificial containers, preference for suburban and forested habitats, and peak adult activity in late summer. (4) Conclusions: Although WNV was not detected, the rapid spread of Aedes japonicus in Poland underlines the need for continued monitoring of its distribution, population dynamics, and potential role in WNV transmission. Full article

Insecticide resistance is increasing globally, and tools must be developed to combat this issue facing mosquito control programs that protect public health and inform operational decisions. Field trials to assess insecticide formulated products (FPs) are logistically demanding and weather-dependent and the Centers for Disease Control and Prevention bottle bioassays are optimized to test technical active ingredient (AI) residue, not aerosolized FP. Here, the methodological gap between AI and FP efficacy testing is addressed. The current study assessed the knockdown/mortality of laboratory and wild populations of Aedes albopictus and Culex pipiens/quinquefasciatus to four FPs (Biomist^®, Duet^®, AquaDuet^®, ReMoa Tri^®) in wind tunnel experiments. The number of FP droplets on mosquitoes was analyzed. Regression analyses showed that droplet counts on mosquitoes were significantly (p < 0.05) related to mosquito mortality for some FPs. The wild Culex population was resistant to all FPs in the wind tunnel. Here, when wind tunnel experiments resulted in a relatively low mortality rate (<90%), this indicates mosquito resistance to the FP. In these situations, a field trial would likely not achieve good results and may not be necessary. Alternatively, when wind tunnel experiments resulted in a nearly perfect mortality rate, a confirmatory field trial could be conducted, if needed. Full article

Aedes (Stegomyia) albopictus (Skuse), a mosquito vector with increasing capacity to transmit human arboviral infections worldwide, naturally harbors the intracellular bacterium Wolbachia spp. This relationship has been observed in native mosquito populations of Ae. albopictus around the world and, more recently, in Mérida, Yucatán, México (abbreviated hereafter as MID). This study provides additional evidence confirming the presence of Wolbachia A (wAlbA) and B (wAlbB) strains in field-collected Ae. albopictus of Mérida, based on wsp gene DNA sequencing analyses of 14 positive PCR samples. Maximum likelihood (ML) analyses of the wsp gene showed high nucleotide sequence homology between Wolbachia from Merida and the globally reported strains A and B, suggesting that these two Wolbachia strains have remained stable in Ae. albopictus over time, regardless of the geographical area. To the best of our knowledge, this is the first report of Wolbachia gene sequencing in native populations of Ae. albopictus in Yucatán, Mexico. Currently many Aedes mosquitoes (e.g., Ae. aegypti) harboring intracellular Wolbachia B bacteria are being released as part of arbovirus and mosquito control programs in Yucatan and globally. Understanding the presence and stability of Wolbachia strains across different Aedes host backgrounds is crucial to ensuring the long-term effectiveness of biological interventions aimed at controlling mosquito populations and arbovirus transmission in endemic areas. Full article

As one of the key vectors for the transmission of Dengue fever, Aedes albopictus is highly ecologically adaptable. The development of environmentally compatible biological defence and control technologies has therefore become an urgent need for vector biological control worldwide. This study constructed and used double-stranded RNA (dsRNA) expression vectors targeting the cyp314a1 and cyp315a1 genes of Ae. albopictus to transform Chlamydomonas reinhardtii and Chlorella vulgaris, achieving RNA interference (RNAi)-mediated gene silencing. The efficacy of the RNAi recombinant algal strain biocide against Ae. albopictus was evaluated by administering it to Ae. albopictus larvae. The results showed that the oral administration of the cyp314a1 and cyp315a1 RNAi recombinant C. reinhardtii/C. vulgaris strains was lethal to Ae. albopictus larvae and severely affected their pupation and emergence. The recombinant algal strains triggered a burst of ROS (Reactive Oxygen Species) in the mosquitoes’ bodies, resulting in significant increases in the activities of the superoxide dismutase (SOD), peroxiredoxin (POD) and catalase (CAT), as well as significant upregulation of the mRNA levels of the CME pathway genes in larvae. In the simulated field experiment, the number of Ae. albopictus was reduced from 1000 to 0 in 16 weeks by the RNAi recombinant Chlorella, which effectively controlled the population of mosquitoes. Meanwhile, the levels of nitrogen (N), phosphorus (P), nitrate, nitrite, ammonia and COD (Chemical Oxygen Demand) in the test water decreased significantly. High-throughput sequencing analyses of 18S rDNA and 16S rDNA showed that, with the release of RNAi recombinant Chlorella into the test water, the biotic community restructuring dominated by resource competition caused by algal bloom, as well as the proliferation of anaerobic bacteria and the decline of aerobic bacteria triggered by anaerobic conditions, are the main trends in the changes in the test water. This study is an important addition to the use of RNAi recombinant microalgae as a biocide. Full article

Carboxylesterases (CCEs) have been demonstrated to be involved in pyrethroid resistance in insect species. This study aims to investigate CCE-mediated resistance mechanisms in Anopheles sinensis, a major malaria vector. Through comparative transcriptomics of a deltamethrin-resistant strain (CQ-LR) versus susceptible strain (WX-LS) of An. sinensis, we identified differentially expressed CCE genes across five developmental stages, five tissues, and three time points post-blood-meal. Four candidate genes (AsAe9, AsAe10, AsAce2, AsUn5) showed significantly upregulated expression. Subsequent qRT-PCR validation across four field-derived resistant strains (WX-LR, AH-LR, YH-LR, CQ-LR) and the susceptible strain confirmed significant upregulation of AsAe9, AsAe10, AsAce1, AsAce2, and AsBe4 in more than two resistant populations. RNAi-based functional validation showed that silencing AsAe10 or AsBe4 in the WX-LR strain significantly decreased knockdown time and raised 24 h mortality upon diagnostic deltamethrin exposure, with AsAe10 silencing having the strongest effect. This study identifies CCE genes involved in deltamethrin resistance in An. sinensis, providing valuable insights into the resistance mechanisms of pyrethroid and a theoretical basis for mosquito resistance management. Full article

Insecticide resistance monitoring is essential for effective mosquito control. This study compared CDC Bottle Bioassays (BBAs) using technical and formulated insecticides (deltamethrin/Deltagard and malathion/Fyfanon EW) against the Culex pipiens complex (Fogg Rd) and Culex tarsalis Coquillett (Vic Fazio). BBAs indicated resistance to deltamethrin and emerging resistance to malathion in Fogg Rd, as well as resistance to both in Vic Fazio. Field trials, however, showed high efficacy: Deltagard caused 97.7% mortality in Fogg Rd and 99.4% in Vic Fazio. Fyfanon EW produced 100% mortality in Fogg Rd but only 47% in Vic Fazio. Extended BBA endpoints at 120 and 180 min aligned better with field outcomes. Deltagard achieved 100% mortality at 120 min in both populations; technical deltamethrin reached 85.7% (Fogg Rd) and 83.5% (Vic Fazio) at 180 min. Fyfanon EW and malathion showed similar performance: 100% mortality was achieved in Fogg Rd by 120 min but was lower in Vic Fazio; malathion reached 55%; and Fyfanon EW reached 58.6% by 180 min. Statistical analysis confirmed that BBAs using formulated products better reflected field performance, particularly when proprietary ingredients were involved. These findings support the use of formulated products and extended observation times in BBAs to improve operational relevance and resistance interpretation in addition to detecting levels of insecticide resistance. Full article

The Asian tiger mosquito Aedes albopictus is a highly invasive species capable of transmitting human pathogens. For population management, the sterile insect technique (SIT) is considered an effective and sustainable alternative to conventional methods, such as insecticides and reducing or eliminating breeding sites. The use of symbiotic bacteria to improve the application of SIT or design combined SIT/incompatible insect technique (IIT) approaches is currently considered. In this context, exploring the microbiota of local mosquito populations is crucial for identifying interesting components. This study employed 16S rRNA sequencing and microbiological methods to characterize the diversity of laboratory and wild Ae. albopictus in Greece. Differences were recorded between wild and lab-reared mosquitoes, with laboratory samples exhibiting higher diversity. Laboratory treatment, sex, and developmental stage also resulted in variations between communities. Populations reared in the same facility developed mostly similar bacterial profiles. Two geographically distant wild populations displayed similar bacterial profiles, characterized by seasonal changes in the relative abundance of Pantoea and Zymobacter. Wolbachia was dominant in most groups (63.7% relative abundance), especially in field-caught mosquitoes. It was identified with two strains, wAlbA (21.5%) and wAlbB (42.2%). Other frequent taxa included Elizabethkingia, Asaia, and Serratia. Blood feeding favored an increase in Serratia abundance. Various Enterobacter, Klebsiella, Aeromonas, and Acinetobacter strains were isolated from larval and adult mosquito extracts and could be further characterized as diet supplements. These findings suggest that the microbiota of local populations is highly variable due to multiple factors. However, they retain core elements shared across populations that may exhibit valuable nutritional or functional roles and could be exploited to improve SIT processes. Full article

New intervention methods and product formulations are needed to better control pyrethroid-resistant Aedes aegypti populations and mitigate the risk of mosquito-borne disease. ReMoa Tri is a novel adulticidal space spray that utilizes a different mode of action than the commonly used adulticides: pyrethroids and organophosphates. As a triple-action space spray, ReMoa Tri combines three components: Fenpropathrin, a mixed-type I/II pyrethroid; abamectin, a macrocyclic lactone; and C8910, a patented fatty acid chain. Prior studies performed by Collier Mosquito Control District showed that ReMoa Tri is effective at controlling type I pyrethroid-resistant Ae. aegypti mosquitoes. To further validate these results and the performance of ReMoa Tri, we conducted a semi-field evaluation using ground and aerial ULV (ultra-low volume) applications with field-caught deltamethrin-resistant Ae. aegypti and a susceptible Ae. aegypti laboratory strain. Ground evaluations tested ReMoa Tri and a type II pyrethroid-based product, DeltaGard. While ReMoa Tri was equally effective against Collier’s deltamethrin-resistant Ae. aegypti and the susceptible laboratory strain, DeltaGard was effective against both strains, with reduced efficacy at farther distances. Similarly, aerial evaluations also showed that ReMoa Tri was equally effective against Collier’s deltamethrin-resistant Ae. aegypti strain and susceptible laboratory strain. This study further confirms ReMoa Tri’s potential as an effective alternative to pyrethroid-based adulticides, both in ground and aerial applications, for managing pyrethroid-resistant Ae. aegypti. Full article

Despite the application of control measures, mosquito-borne diseases continue to pose a serious threat to human health. In this context, exploiting Wolbachia, a common symbiotic bacterium in insects, may offer effective solutions to suppress vectors or reduce their competence in transmitting several arboviruses. Many Wolbachia strains can induce conditional egg sterility, known as cytoplasmic incompatibility (CI), when infected males mate with females that do not harbor the same Wolbachia infection. Infected males can be mass-reared and then released to compete with wild males, reducing the likelihood of wild females encountering a fertile mate. Furthermore, certain Wolbachia strains can reduce the competence of mosquitoes to transmit several RNA viruses. Through CI, Wolbachia-infected individuals can spread within the population, leading to an increased frequency of mosquitoes with a reduced ability to transmit pathogens. Using artificial methods, Wolbachia can be horizontally transferred between species, allowing the establishment of various laboratory lines of mosquito vector species that, without any additional treatment, can produce sterilizing males or females with reduced vector competence, which can be used subsequently to replace wild populations. This manuscript reviews the current knowledge in this field, describing the different approaches and evaluating their efficacy, safety, and sustainability. Successes, challenges, and future perspectives are discussed in the context of the current spread of several arboviral diseases, the rise of insecticide resistance in mosquito populations, and the impact of climate change. In this context, we explore the necessity of coordinating efforts among all stakeholders to maximize disease control. We discuss how the involvement of diverse expertise—ranging from new biotechnologies to mechanistic modeling of eco-epidemiological interactions between hosts, vectors, Wolbachia, and pathogens—becomes increasingly crucial. This coordination is especially important in light of the added complexity introduced by Wolbachia and the ongoing challenges posed by global change. Full article

Aedes albopictus is one of the most important vectors of Dengue, which poses a serious threat to public health. The bacterial microbiota has an effect on the parameters of mosquitos, such as larval development and fecundity, and it has emerged as a promising field to be explored for novel environmentally friendly control strategies. Rahnella sp. are present in many insects, including Ae. Albopictus, and play a role in bacterial–insect interactions; however, the role of the bacteria in mosquito biology has not yet been characterized. In this study, we characterized the Rahnella isolate RAeA1 obtained from Ae. albopcitus, and its colonization stability in Ae. albopictus was investigated by generating GFP-tagged bacteria. The influences of the bacteria on larval development and mosquito reproductive capacity were evaluated by inoculating RAeA1 in axenic larvae and antibiotic-treated adult mosquitoes, respectively. The results indicated that RAeA1, which is widespread in the field population of Ae. albopictus, can be transmitted directly from the parental strain to the progeny and can rescue axenic larvae developing into adults with a prolonged development time to pupation. RAeA1 inoculation can impair egg production and ovary maturation, as well as reducing the synthesis of ecdysteroids and vitellogenin in Ae. albopictus females. Overall, our results provide a thorough study of bacterium function characterization that will facilitate the development of potential strategies in relation to the design of microbiomes for vector control. Full article

The emergence of insecticide resistance among malaria vector populations poses a significant threat to existing malaria vector control tools. This phenomenon necessitates an increased pace of developing and deploying new effective compounds in insecticides for vector control. Therefore, this study investigated the comparative performance of newly formulated indoor residual spray compounds, Klypson 500WG (Clothianidin alone) and 2GARD-WP (a mixture of Clothianidin 50% and Deltamethrin 6.25%) against An. gambiae in the lower Moshi area of the rural Moshi district, Tanzania. Before the wall cone bioassay tests, the susceptibility of field-collected adult An. gambiae s.l. to 0.75% Permethrin, 2% Klypson 500WG, 0.05% Deltamethrin, and 0.25% Pirimiphos-methyl was assessed following WHO procedures. For the cone-bioassay testing, 160 houses were randomly selected and sprayed with Klypson 500WG and 2GARD-WP. For the walls sprayed with Klypson 500WG and 2GARD-WP, the knockdown rate of Anopheles gambiae after 60 min of exposure over six months ranged from 70% to 98%, with mortality rates after 24 to 168 h consistently exceeding 90% across all villages and wall types throughout the six months. The susceptibility of wild-collected mosquitoes to Pirimiphos-Methyl, Permethrin, Deltamethrin, and Klypson 500WG was 61, 81, 86, and 93%, respectively. These findings suggest that Klypson 500WG and 2GARD-WP are suitable alternative insecticides that can be incorporated in the vector control toolbox used for malaria control. Full article

Interspecific competition between mosquito larvae may affects adult vectorial capacity, potentially reducing disease transmission. It also influences population dynamics, and cannibalistic and predatory behaviors. However, knowledge of interspecific competition between Ae. aegypti and Anopheles species is limited. The study examined interspecific competition between Ae. aegypti larvae and either An.arabiensis, An. gambiae, or An. funestus on individual fitness in semi-field settings. The experiments involved density combinations of 100:100, 200:0, and 0:200 (Ae. aegypti: Anopheles), reared with and without food, in small habitats (8.5 cm height × 15 cm diameter) with 0.5 liters of water and large habitats (15 cm height × 35 cm diameter) with 1 liter of water. The first group received Tetramin^® fish food (0.02 g), while the second group was unfed to assess cannibalism and predation. While interspecific competition affected both genera, Anopheles species experienced greater effects, with reduced survival and delayed development, compared to Ae. aegypti. The mean wing lengths of all species were significantly small in small habitats with a mixed population (p < 0.001). The presence of food reduced cannibalism and predation compared to its absence. These interactions have implications for diseases transmission dynamics and can serve as biological indicators to signal the impacts of vector control interventions. Full article

Background: The swift expansion of the invasive malaria vector Anopheles stephensi throughout Africa presents a major challenge to malaria control initiatives. Unlike the native African vectors, An. stephensi thrives in urban settings and has developed resistance to multiple classes of insecticides, including pyrethroids, organophosphates, and carbamates. Methods: Insecticide susceptibility tests were performed on field-collected An. stephensi mosquitoes from Awash Sebac Kilo, Ethiopia, to assess insecticide resistance levels. Illumina RNA-seq analysis was then employed to compare the transcriptomes of field-resistant populations and susceptible laboratory strains (STE2). Results: An. stephensi populations exhibited high levels of resistance to both deltamethrin (mortality, 39.4 ± 6.0%) and permethrin (mortality, 59.3 ± 26.3%) in WHO tube bioassays. RNA-seq analysis revealed that both field-resistant and field-unexposed populations exhibited increased expressions of genes associated with pyrethroid resistance, including esterases, P450s, and GSTs, compared to the susceptible STE2 strain. Notably, esterase E4 and venom carboxylesterase-6 were significantly overexpressed, up to 70-fold, compared to the laboratory strain. Functional enrichment analysis revealed a significant overrepresentation of genes associated with catalytic activity under molecular functions and metabolic process under biological process. Using weighted gene co-expression network analysis (WGCNA), we identified two co-expression modules (green and blue) that included 48 genes strongly linked to pyrethroid insecticide resistance. A co-expression network was subsequently built based on the weight values within these modules. Conclusions: This study highlights the role of esterases in the pyrethroid resistance of an An. stephensi population. The identification of candidate genes associated with insecticide resistance will facilitate the development of rapid diagnostic tools to monitor resistance trends. Full article

The future of Aedes aegypti control emphasizes the transition from traditional insecticides toward more sustainable and multisectoral integrated strategies, like using Wolbachia-carrying mosquitoes for population suppression or replacement. We reviewed the integration of the successful Mexican initiative, “Mosquitos Buenos”, with the key challenges outlined in the PAHO guidelines for incorporating innovative approaches into vector control programs. These challenges include establishing essential infrastructure, training personnel, managing field operations, and fostering community support. Our experience provides critical evidence to support the strategic National Plan for implementing and integrating IIT-SIT technologies to control Ae. aegypti and dengue. Furthermore, this experience serves as a foundation for other countries in the region interested in adopting these technologies. It underscores the importance of strategic planning, multisectoral collaboration, continuous evaluation, and scaling up innovative tools to ensure their long-term effectiveness and sustainability in urban areas where Aedes vectors and the diseases they transmit are endemic. Full article