Globe-Trotting Aedes aegypti and Aedes albopictus: Risk Factors for Arbovirus Pandemics

Effects of mosquito-proofing storm drains on adult and larvae mosquito abundance: Protocol of the IDAlErt storm drAin randomiSed controlled trial (IDEAS)

Aedes and Culex mosquitoes, known for spreading arboviruses like dengue and West Nile, thrive in cities, posing health risks to urban populations. Climate change can create suitable climatic conditions for these vectors to spread further in Europe. Cities contain numerous landscape and infrastructure elements, such as storm drains, that allow stagnant water build-up facilitating mosquito breeding. Modifying urban infrastructure to prevent water accumulation can reduce mosquito populations, but evidence is limited. The Public Health Agency of Barcelona, Spain, introduced a structural modification of storm drains to prevent water accumulation. Together with the Agency, we designed a randomised controlled trial (RCT) to experimentally assess the effectiveness of these modifications on adult Aedes albopictus and Culex pipiens populations. It is a parallel-arm RCT with equal randomization of 44 drains to receive mosquito-proofing modifications (intervention) or not (control). Primary outcomes are adult mosquito counts and secondary outcomes are larvae and mosquito presence, assessed weekly at each drain until no mosquitoes are detected. Data analyses include generalised linear mixed models to estimate the time-averaged and highest intervention effects, subgroup and sensitivity analyses. The trial results will guide a city-wide expansion of the storm drain modifications and provide valuable evidence to enhance existing vector control measures.

Characterization, functional exploration, and evolutionary analysis of mirtronic microRNAs reveal their origin in the invasive vector mosquito, Aedes albopictus

The mirtron pathway represents a distinct category of noncanonical microRNA (miRNA) biogenesis mechanisms. Current studies suggest that the mirtron pathway may be widely prevalent across various taxa, including animals and plants, but investigation of this pathway has focused mainly on mammals, particularly humans, and the biological functions and emerging roles of several mirtrons in human diseases have been elucidated. In the context of insects, mirtrons have only been comprehensively characterized and preliminarily functionally analyzed in Drosophila. The Asian tiger mosquito, Aedes albopictus, is a highly invasive species and an important vector of arbovirus transmission to humans. Although canonical miRNA function has been studied in depth in mosquitoes, the role of mirtrons in this species remains to be revealed. In this study, we identified and validated 2 novel conventional mirtrons in Ae. albopictus that are precursors of miR-11900 and miR-11893. Mirtronic miRNA biogenesis depends on the splicing of introns and cleavage by Dicer but does not necessarily correlate with intron location in host genes. The molecular evolution of mirtrons was analyzed using methods based on host genes and their exon‒intron architecture; the results indicate that mirtronic miRNAs are relatively young and that they may have appeared in Culicinae after the Anophelinae and Culicinae diverged. According to small RNA sequencing (RNA-seq) and RNA-seq data on post-mirtronic miRNA overexpression, mosquito mirtronic miRNAs are present in low abundance, and the absence of typical target genes in Ae. albopictus suggests they are not involved in post-transcriptional gene regulation. Overall, our results indicate that the emergence of 2 mirtrons in Ae. albopictus is likely due to the formation of Dicer-recognized secondary structures during the evolution of the intron sequence; these structures are similar to byproducts processed by Dicer, and their abundance is controlled by an alternative adventitious mirtron emergence-dependent mechanism. Our study identifies for the 1st time mirtrons in insect species distinct from Drosophila melanogaster, provides new insights into mirtron evolution, and provides a reference for the functional analysis of mirtrons.

Evaluation on activity and efficacy of Bacillus thuringiensis var. israelensis and S-methoprene against the Asian tiger mosquito, Aedes albopictus (Diptera: Culicidae), in discarded tires

The Asian tiger mosquito, Aedes albopictus Skuse (Diptera: Culicidae), is an important vector of various arboviruses. Effective control of mosquito vectors is essential to prevent the transmission of mosquito-borne diseases; however, sustainable larval control against this species has been notoriously difficult. To enhance effective larval control against Ae. albopictus, a laboratory initial test was conducted to determine the activity of microbial larvicide Bacillus thuringiensis var. israelensis (Bti) and a juvenile hormone analog S-methoprene. The technical grade and formulated product performed similarly in either Bti or S-methoprene. Compared with larvae from a laboratory strain, field-collected mosquitoes showed similar susceptibility to Bti, but significantly lower susceptibility to S-methoprene at IE30 and IE50. In semifield studies to evaluate efficacy of the formulations, as short as a 2-d efficacy was observed for Bti alone at 0.50 ppm, while longer efficacy of up to 3 and 4 wk was achieved by the S-methoprene treatments alone at 1 and 5 ppb, respectively, due to different modes of action and formulation technologies. The combination of Bti at 0.25 ppm and S-methoprene at 2.5 ppb exhibited an extended effect for up to 4 wk as in S-methoprene alone at 5 ppb. The efficacy of both insecticides was impacted by sunlight and dilution. Larvae from field collections were less susceptible to S-methoprene than those of laboratory colony in the semifield evaluation in discarded tires. The practicality of Bti and S-methoprene products for controlling Ae. albopictus in discarded tires was discussed in relation to the findings in current studies.

Chemical Composition and Pesticidal Activities Against Three Vector Mosquito Species of Zanthoxylum armatum DC. Essential Oils

In this study, we investigated the extraction yield and chemical composition of essential oils from the fruit, leaf, and twig of Zanthoxylum armatum from Vietnam. The fruit essential oil (FEO) with high content, representing a chemotype, was evaluated for pesticidal activities against three mosquito species Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus, according to the WHO guidelines with modifications. The results showed that the major constituents of FEO were limonene (30.50%), sabinene (15.16%), terpinen-4-ol (13.05%), and γ-terpinene (7.49%). The major constituents of leaf essential oil (LEO) were sabinene (20%), 1,8-cineole (16.97%), limonene (12.32%), and 2-undecanone (9.17%). The twig essential oil (TEO) was rich in ketones (73.84%), with the main constituents being 2-undecanone (47.33%) and 2-tridecanone (26.14%). FEO exhibited potential pesticidal activities: larvicidal activities with 24-h LC50 values ranging from 21.55 to 29.53 µg/mL inhibited the biting of A. aegypti adults with a protection time of 176.5 ± 40.20 min, and exhibited potent adulticidal activities against A. aegypti. In addition, FEO did not exhibit cytotoxicity against the normal Vero cell line. This study contributes an evidence base to support the future development and use of FEO as a promising biopesticide agent for the control of disease-transmitting mosquito species and altering synthetic pesticides.

Environmental yeasts differentially impact the development and oviposition behavior of the Asian tiger mosquito Aedes albopictus

BACKGROUND

While the Asian tiger mosquito (Aedes albopictus), a known vector of many arboviruses, establishes symbiotic associations with environmentally acquired yeasts, their impact on mosquito biology remains poorly investigated. To better understand these associations, we hypothesized that waterborne yeasts colonizing the larval gut differentially support mosquito development based on their capacity to produce riboflavin or recycle nitrogen waste into proteins by secreting uricase, as B vitamins and amino acids are crucial for mosquito development. To address this hypothesis, we used axenic and gnotobiotic insects to gauge the specific impact of different environmental yeasts on Ae. albopictus development and survival. We then evaluated whether the observed variations across yeast species could be linked to differential uricolytic activities and varying quantities of riboflavin and proteins in insecta. Finally, given that mosquito oviposition site selection favors conditions that enhance offspring performance, we tested whether yeasts that promote faster development mediate oviposition site selection by gravid females.

RESULTS

Differences in mosquito development times were observed based on the environmental yeast used. Yeasts like Rhodotorula mucilaginosa and Aureobasidium pullulans promoted rapid development and were associated with improved survival. Conversely, yeasts such as Torulaspora delbrueckii and Martiniozyma asiatica, which led to slower development, produced smaller adults. Notably, R. mucilaginosa, which promoted the fastest development, provided high riboflavin intakes and enhance nitrogenous waste recycling and protein synthesis through strong uricolytic-ureolytic activity. Behavioral experiments indicated that yeasts promoting rapid development "attract gravid females.

CONCLUSIONS

Our findings highlight that a set of environmental yeasts present in natural larval breeding sites can be associated with improved mosquito development and survival by enhancing nutritional intake, thereby attracting gravid females. Variations in mosquito development time are likely linked to the differential levels of riboflavin production and nitrogenous waste recycling capacities among yeast species. This study opens new perspectives on the trophic interactions between mosquitoes and their mycobiota, emphasizing the importance of nitrogen-containing molecules such as essential amino acids, proteins, or vitamins provided by the mycobiota. Video Abstract.

Boosting the efficacy of fungal biocontrol: miRNA339-5p-mediated mosquito immunity regulation

BACKGROUND

Aedes mosquitoes are vectors for numerous viral diseases, including dengue, zika, chikungunya, and yellow fever. Therefore, underscoring the urgent need for eco-friendly alternatives to combat insecticide resistance and the scarcity of effective vaccines. Entomopathogenic fungi present a sustainable alternative to chemical insecticides; however, their widespread application is limited by their relatively low virulence.

RESULTS

Here, we investigated the immunological interactions between Metarhizium anisopliae and Aedes albopictus, demonstrating that fungal infection significantly up-regulated immune-related genes in the Toll and melanization pathways, thereby enhancing antifungal and antibacterial defenses at 48 h post-infection (hpi). Small RNA sequencing identified miR339-5p as a crucial modulator, targeting the immune genes Gram-Negative Binding Protein 1 (GNBP1) and CLIP-domain Serine Protease B15 (CLIPB15), which are critical for Toll and phenoloxidase (PO) pathway activation. The administration of a synthetic miR339-5p mimic increased fungal virulence, resulting in a higher mortality rate among adult mosquitoes and a significant increase in the mortality rate of mosquito larvae within 24 hpi. GNBP1 was found to regulate both Toll and PO pathways, while CLIPB15 specifically modulated the PO system by cleaving prophenoloxidase (PPO).

CONCLUSION

This research highlights the potential of leveraging Ae. albopictus-encoded miR339-5p through advanced genetic engineering techniques to bolster the efficacy of existing fungal-based mosquito control strategies, providing a promising approach in the fight against mosquito-borne diseases. © 2024 Society of Chemical Industry.

Aedes aegypti reproductive aspects: constant light significantly affects the embryonic development

BACKGROUND

The importance of the mosquito Aedes aegypti as a vector of arboviruses like dengue, Zika, and chikungunya justifies the interest in investigating this species' physiology and reproductive biology. For the maintenance and expansion of Ae. aegypti populations, copulation, oogenesis, female oviposition capacity, embryo development and larval hatching are crucial processes regulated by biological clocks. Many of these parameters have currently been investigated under environmental and laboratory conditions. However, there are specific gaps regarding the effect of light on these critical reproductive aspects. In this study, the influence of light on some aspects of Ae. aegypti biology was evaluated.

OBJECTIVES

We investigated, in laboratory conditions, the effects of constant light on Ae. aegypti reproductive features: spermathecal content, embryo morphology, females' fecundity, and egg viability.

METHODS

Morphological and physiological assays were performed using Ae. aegypti females and eggs obtained from forced egg laying. The reproductive aspects were analysed under constant light (LL = light/light) and light/dark cycles (LD12:12 = 12 h of light and 12 h of dark).

FINDINGS AND MAIN CONCLUSIONS

Our results proved the negative effect of constant light on egg production (decreasing the fecundity) and embryonic development (causing a drop in egg viability and perceptive damage in the embryos). The results presented here bring new information on the impacts that a source of constant light may have on the reproductive biology of Ae. aegypti.

Sticky traps for Aedes aegypti surveillance and targeted vector control in Sincelejo, Colombia

INTRODUCTION

Entomological surveillance of adult Aedes aegypti mosquitoes provides better risk indicators than in immature stages.

OBJECTIVE

To determine the usefulness of MosquiTRAP™ traps for Ae. aegypti surveillance, targeted vector control, and the design of dengue prevention measures in Sincelejo, Colombia.

MATERIALS AND METHODS

Forty-nine MosquiTRAP™ traps were deployed over six months to capture gravid Ae. aegypti females in two neighborhoods with historical reports of dengue cases. Entomological indices were calculated to monitor mosquito population dynamics, and the infection frequency of the captured mosquitoes with dengue, zika, and chikungunya virus were assessed. The rates of trap approval and adherence were evaluated, and risk maps were developed based on mosquito abundance. These maps facilitated the identification of specific areas for targeted vector control interventions.

RESULTS

A total of 1,475 mosquitoes were captured, of which 99.1% were identified as A. aegypti. The trap positivity index ranged from 85.7 to 42.9% per inspection, with a mean female Aedes index of two to three mosquitoes per house. Evidence of Ae. aegypti infestation was observed in both neighborhoods, although specific hotspots of high mosquito abundance were identified. No viral infection was detected in the captured mosquitoes.

CONCLUSIONS

MosquiTRAP™ traps are useful for Ae. aegypti surveillance as a potential tool to guide vector control and prevention measures for diseases transmitted by this mosquito species.

Global impact of parasitic infections and the importance of parasite control

Parasites have a severe impact on animal and human health. Parasites like worms, ticks, mites, fleas, biting flies, mosquitoes, and pathogenic protozoa affect humans and their pets as well as their livestock globally, both in terms of severity and numbers. Parasitic infections are a global phenomenon, and they can be associated with severe or mild symptoms but represent a continuous risk of severe diseases for animals and humans. Therefore, effective treatment options and the prevention of infection are key for the wellbeing of pets, livestock, and humans, including the reduction of zoonotic risk of infection. The effective control of parasites in animals can greatly improve their quality of life and is also beneficial for humans; this is threatened by drug-resistant parasite populations. Today's key areas for improvement of parasite control are as follows: a) convenience of prevention and treatment, b) effectiveness against drug-resistant parasites, c) availability and reduced costs of treatment, and d) control measurements that are environmentally friendly.

Molecular cloning and functional characterizations of transient receptor potential A1 (TRPA1) in Aedes albopictus

Aedes albopictus is a potent vector of major arboviruses that cause serious health burdens and economic losses in worldwide. To facilitate the exploration of potential mosquito repellents, the Ae. albopictus TRPA1 (AalTRPA1) gene was cloned and investigated its molecular characteristics by bioinformatics techniques and the function using electrophysiological and RNAi techniques. In vitro expression and electrophysiological analysis of Xenopus oocytes showed that high temperature and allyl isothiocyanate (AITC) could activate the AalTRPA1 channel. After interfering with this gene, Ae. albopictus was insensitive to temperature changes, was more easily hurt and shot down by noxious heat; it was also insensitive to catnip, and the effect of repellent was poor. We firstly identified the molecular characterization of AalTRPA1 subfamily genes and their key role in temperature and irritant perception in Ae. albopictus, and then the AalTRPA1 has the potential to develop a new mosquito repellent target against Ae. albopictus.

Tracing the Trajectory of Aedes aegypti and Aedes albopictus Research: Eight Decades of Bibliometric Retrospect

Background: The global burden of mosquito-borne diseases transmitted by Aedes aegypti and Aedes albopictus mosquitoes has become a pressing public health concern. This study sought to quantify and evaluate about eight decades of publication data on the global epidemiological trend of the diseases transmitted by A. aegypti and A. albopictus. Methods: A comprehensive bibliographic review of literature was performed on A. aegypti and A. albopictus transmitted diseases, focusing on disease transmission, epidemiological trends, vector control strategies, surveillance and monitoring, and international collaborations and initiatives. Extensive data were collected from the Web of Science database and analyzed for citation network analysis (CNA) using VoSviewer software. Data were collected from the Web of Science database encompassing various aspects of Aedes-borne diseases. The bibliographic CNA was performed to quantify and analyze the 77 years of data on A. aegypti and A. albopictus transmitted diseases. Results: The analysis included 4149 publications contributed by 13,416 authors from 149 countries. These articles comprised research articles (91.01%), review articles (6.267%), proceeding papers (1.76%), and book chapters (0.92%). The results revealed a cumulative h-index of 134, indicating the impact of the scientific output in this field. Conclusion: This review contributes to the ongoing efforts to mitigate the impact of Aedes-borne diseases and protect public health worldwide. By synthesizing current knowledge and evidence-based practices, the study provides all information related to publications, citations, co-citations, top journal trends, high-impact publications, and collaborations among authors in one place among the data published in the past eight decades on Aedes-borne diseases.

Use of lyophilized larval extracts associated with Bti in Double BR-OVT trap: Strategy to attract and kill mosquitoes of the genera Aedes and Culex

The present study evaluated the efficiency of the larval extract of Aedes aegypti associated with Bacillus thrurigiensis var. israelensis as oviposition bait to enhance the attractiveness of the Double BR-OVT trap. In the laboratory, paired tests were carried out, using two oviposition sites. Thirty pregnant females of A. aegypti were used per test. In the field, paired traps were installed at eight points. The test traps (2 g larval extract + 1 g Bti/ 2 L), controls (1 g Bti/ 2 L). For tests with lyophilized extract, each test trap contained 0.26 g/lyophilized larvae + 1 g Bti/ 2 L. Laboratory results showed that all cups treated (68.8 %/ 842 ± 177; 72.5 %/ 822 ± 167; 70.4 %/ 904 ± 169, respectively), with or without Bti, collected more eggs. In the field, traps treated with larval extract or lyophilized plus Bti collected more Aedes spp eggs (64 %/ 582 ± 467; 62.5 %/ 511 ± 531) and C. quinquefasciatus (65 %/ 11 ± 10; 70 %/ 5 ± 4.3) rafts. The association of Double BR-OVTs traps with larval extract plus Bti proves to be efficient alternatives for the integrated control, with the strategy of attracting and eliminating mosquitoes.

miR-2940-1 is involved in the circadian regulation of oviposition in Aedes albopictus

The vast majority of all global species have circadian rhythm cycles that allow them to adapt to natural environments. These regular rhythms are regulated by core clock genes and recent studies have also implicated roles for microRNAs in this regulation. Oviposition is an important circadian behavior in the reproductive cycle of insect vectors of diseases, and little is known about the rhythm or its regulation in mosquitoes. Aedes albopictus is a diurnal mosquito that transmits arboviruses and is the major cause of outbreaks of dengue fever in China. We analyzed the oviposition rhythm patterns of A. albopictus under different light/dark conditions and show that the mosquitoes have an oviposition peak between zeitgeber time 9 (ZT 9) and ZT 12. Furthermore, the antagomir-mediated knockdown of expression of the microRNA miR-2940-1 affected the oviposition rhythm of A. albopictus. These data support the conclusion that miR-2940-1 is involved in the regulation of oviposition rhythm in A. albopictus and provide a foundation for using oviposition rhythms as a new target for vector mosquito control.

Pseudomonas aeruginosa Rhamnolipids Produced by Andiroba (Carapa guianensis Aubl.) (Sapindales: Meliaceae) Biomass Waste from Amazon: A Potential Weapon Against Aedes aegypti L. (Diptera: Culicidae)

Rhamnolipids, biosurfactants synthesized from natural resources, demonstrate significant applications, including notable insecticidal efficacy against Aedes aegypti L., the primary vector for numerous arboviruses. The global spread of A. aegypti poses substantial public health challenges, requiring innovative and sustainable control strategies. This research investigates the use of andiroba (Carapa guianensis Aubl.) biomass waste as a substrate for synthesizing a rhamnolipid biosurfactant (BSAW) produced by Pseudomonas aeruginosa and evaluates its insecticidal activity against A. aegypti. The findings indicate a biosurfactant yield of 4.42 mg mL-1, alongside an emulsification index approaching 60%. BSAW successfully reduced both surface and interfacial tensions to below 30 mN/m and 4 mN/m, respectively. Characterization revealed that BSAW is a di-rhamnolipid, consisting of two rhamnose units covalently linked to a saturated C10 fatty acid chain. At a concentration of 1.0 mg mL-1, BSAW exhibited notable larvicidal activity, leading to structural impairments and cellular dysfunctions in A. aegypti larvae while also disrupting their associated bacterial microbiota. Moreover, BSAW effectively deterred oviposition in adult mosquitoes. These findings underscore BSAW's potential to compromise various developmental stages of A. aegypti, supporting integrated arbovirus management approaches. Furthermore, this research emphasizes the feasibility of utilizing agro-industrial waste as substrates for microbial rhamnolipid production.

Diversity, abundance of anopheline species, and malaria transmission dynamics in high-altitude areas of western Cameroon

Background

Assessing vector bionomics is crucial to improving vector control strategies. Several entomological studies have been conducted to describe malaria transmission in different eco-epidemiological settings in Cameroon; knowledge gaps persist, particularly in highland areas. This study aimed to characterize malaria vectors in three localities along an altitudinal gradient in the western region: Santchou (700 m), Dschang (1400 m), and Penka Michel (1500 m).

Methods

Human landing catches were conducted from May to June 2023 from 6:00 pm to 9:00 am. Mosquitoes were sorted into genera, and all Anopheles species were identified using morphological taxonomic keys and species-specific Polymerase Chain reaction (PCR). Entomological indicators were assessed including species composition and abundance, biting behavior, infection rate, and entomological inoculation rate (EIR). Genomic DNA from the head and thoraces were tested for Plasmodiuminfection by real-time PCR.

Results

2,835 Anopheles mosquitoes were identified, including An. gambiae, An. coluzzii, An. funestus, An. leesoni, An. nili, and An. ziemanni, with An. gambiae being the most prevalent at all sites. The human-biting rate of An. gambiae s.l. was significantly higher (p-value < 0.001) in Penka Michel compared to Santchou and Dschang (45.25 b/h/n vs 3.1 b/h/n and 0.41 b/h/n), and appears to be the most infected vector, and infectious vector distribution is highly focal, with entomological inoculation rates 13-fold higher in Penka Michel compared to Santchou (1.11 vs 0.08ibites/human/night). P. falciparum was the dominant malaria parasite (67% at Santchou, 62% at Penka Michel), but P. malariae (30%) and P. ovale (1.21%) infections were also detected.

Conclusion

The study highlights a difference in mosquito composition and host-seeking behavior with altitude and the need for continued surveillance to monitor vector populations and prevent potential malaria outbreaks in these highland areas.

Spatial-temporal distribution of chikungunya virus in Brazil: a review on the circulating viral genotypes and Aedes (Stegomyia) albopictus as a potential vector

Chikungunya virus (CHIKV) is mainly transmitted by the invasive mosquito Aedes (Stegomyia) aegypti in tropical and subtropical regions worldwide. However, genetic adaptations of the virus to the peri domestic mosquito vector Aedes (Stegomyia) albopictus has resulted in enhanced vector competence and associated epidemics and may contribute to further geographic expansion of CHIKV. However, evidence-based data on the relative role of Ae. albopictus in CHIKV transmission dynamics are scarce, especially in regions where Ae. aegypti is the main vector, such as in Brazil. Here, we review the CHIKV genotypes circulating in Brazil, spatial and temporal distribution of Chikungunya cases in Brazil, and susceptibility to infection and transmission (i.e., vector competence) of Ae. albopictus for CHIKV to better understand its relative contribution to the virus transmission dynamics.

Larvicidal activity of terpenes and their derivatives against Aedes aegypti: a systematic review and meta-analysis

Aedes aegypti (Diptera: Culicidae) is the primary arthropod vector responsible for the transmission of dengue, which is present in more than one hundred countries. The application of synthetic larvicides is one of the most common strategies used for dengue control, but their prolonged use can cause larvicide resistance or tolerance, environmental damage, and have toxic effects on human and animal health. Thus, faced with this problem, there have been increasing efforts to find alternative larvicides against Ae. Aegypti. This search has been mainly focused on naturally occurring chemical compounds, driven by the evidence of their potential effectiveness, and by a desire to find more sustainable, environmentally friendly, and safe alternatives to synthetic larvicides. Thus, the present study aimed to review the effects of terpenes and their derivatives on mortality of the Ae. aegypti larvae, focusing mainly on a lethal concentration of 50% (LC50), in addition to summarizing information on its mechanisms of action and effects on non-target organisms. We searched the main databases for studies published up to April 2024 using relevant keywords, and data were extracted and analyzed qualitatively and quantitatively. Twenty-one articles describing 69 different terpenes and derivatives met the criteria of the review and meta-analysis. Among them, 76.8% were terpenoids and 23.2% terpenes. The LC50 ranged from 0.4 to 1628.2 ppm. The present review and meta-analysis showed that the terpenes and terpenoids can be promising chemical templates for use in eco-friendly larvicides against Ae. aegypti.

Larvicidal and enzyme inhibition effects of Phoenix pusilla derived Methyl oleate and malathion on Aedes aegypti strains

This study explores the larvicidal potential of methanolic flower extracts from Phoenix pusilla (Pp-Fe), its major compound, and malathion (MLT), against laboratory strain (LS) and field strain (FS) of Aedes aegypti, the dengue mosquito vector. We identified thirty-one derivatives, with methyl oleate (MO) comprising 28.5% of Pp-Fe. Comparative efficacy evaluations were performed using peak dosages of Pp-Fe (500 ppm), MO (5 ppm), and MLT (5 ppm) on LS and FS larvae. Both LS and FS second instars showed higher susceptibility to Pp-Fe (95% and 93%, respectively) and MO (85% and 83%, respectively). MLT resulted in significant mortality rates among LS larvae (98%) and notable reductions among FS larvae (71%). The expression levels of key biomarker enzymes (carboxylesterase, GST, and CYP450) exhibited a consistent decrease and subsequent upregulation in LS and FS larvae following exposure to Pp-Fe and MO, contrasting with the significant expression variations observed in LS and FS larvae exposed to MLT. LS larvae demonstrated heightened susceptibility and evident midgut cell damage following all treatments, suggesting potential disparities in susceptibility and adaptive responses between LS and FS strains towards MLT. These observations underscore the promising larvicidal attributes of Pp-Fe and MO, emphasizing the need for further exploration of their mechanisms of action in the development of environmentally sustainable mosquito control strategies and resistance management.

Host diversity of Aedes albopictus in relation to invasion history: a meta-analysis of blood-feeding studies

BACKGROUND

The invasive mosquito Aedes albopictus is a major concern for human and animal health given its high potential to spread over large geographical distances, adapt to various habitats and food sources, and act as a vector for pathogens. It is crucial to understand how this species establishes ecological relationships at different locations, as it determines its role in transmission of diseases.

METHODS

Based on published blood meal surveys, a meta-analysis was performed to investigate how host diversity changes along the process of invasion at a large scale. For 48 independent localities, the Shannon diversity index was calculated and was then assessed against several moderator variables describing invasion status, habitat type, methodology, survey year and the year of introduction for invasive populations.

RESULTS

Diet diversity was higher in the invasive than in the native populations when the strong habitat effects were held constant. Furthermore, the year of introduction also had a significant role, as invasive populations that had been established earlier had wider diet diversity than more recent populations.

CONCLUSIONS

Invasive Ae. albopictus has considerable ecological flexibility. The species' ability to adapt to various food sources goes hand in hand with its successful worldwide dispersion, which has strong implications for its role in pathogen transmission.

Influence of adult body size on blood feeding behavior and eggs retention in Aedes albopictus (Diptera: Culicidae)

Mosquito-borne viruses continue to affect billions of people globally, posing a severe health risk and an economic burden. Aedes albopictus (Skuse), a highly invasive mosquito species, has repeatedly invaded and increased its presence, serving as a key vector of dengue virus, yellow fever virus (YFV), Zika virus (ZIKV), and Chikungunya virus (CHIKV), causing frequent outbreaks of related viral diseases. This study investigated the impact of larval diet quantity on larval duration and adult body size. The effect of adult mosquito body size on various aspects of Ae. albopictus was also examined, including blood-feeding behavior, follicular development, reproductive capacity, egg retention capacity, preoviposition period, and fecundity. These diverse characteristics all have an effect on arboviruses transmission. The changes in body size (small, medium, and large) are obtained by providing different quantities of larval diet (low, average, and high). The results indicate that the quantity of larval diet directly impacts the adult body size while inversely affecting the larval duration. Furthermore, a positive correlation exists between adult body size and wing length, implying that wing length could be a reliable indicator of adult body size and rearing conditions during the developmental stages. Large females exhibited higher numbers of follicles and greater fecundity. Moreover, a significant correlation was observed between follicle number before the first blood meal and total egg number. In contrast, increasing wing length decreased the number of blood meals, egg retention, and the preoviposition period. The tendency of small females to perform multiple feedings was greater than that of large females. Small females exhibited a higher propensity for multiple feeding activities when compared to their larger counterparts. Most medium-sized females (92.8%) deposited eggs in their ovaries, however, 7.2% retained a few. In contrast, most large females (87.4%) had complete ovary egg-laying, whereas a minority (12.6%) retained some of their eggs. About 35.2% of small females showed ovarian egg retention, while 64.8% successfully laid all their eggs. After the first blood meal, the oviposition rate was 92% for large females, 88% for medium females, and 76% for small females. About 69.86% of the follicles in large females underwent vitellogenesis. This finding suggests that small females with low energy reserves exhibited incomplete oviposition and multiple blood feedings to increase their reproductive capacity. RESEARCH HIGHLIGHTS: Add more information about arbovirus epidemics and their consequences. Aedes albopictus is a global invasive species that transmit dengue virus, CHIKV, YFV, and ZIKV. A negative correlation was observed between body size, egg retention, and multiple blood feedings in Aedes albopictus. Size of the female's body was positively correlated with fecundity, while it was negatively correlated with the preoviposition period. Size-dependent multiple blood feeding affects vector-host contact frequency.

Diflubenzuron larvicide auto-dissemination: A modeling study

Proposing substitutes for Pyriproxyfen (PPF) in the auto-dissemination strategy is essential to ensure the continuity of the strategy in the field, especially in the case of the emergence of populations resistant to this larvicide. One possible substitute among the compounds already in use in Brazil is the larvicide Diflubenzuron (DFB). The equation that defines the proportion of oviposition sites (habitats) contaminated by the auto-dissemination strategy was modified to account for the number of visits required to reach the necessary concentration of DFB for contamination, considering scenarios with varying numbers of oviposition sites and mosquito densities. The dissemination was evaluated in oviposition sites of 2 L, 1.5 L, 1 L, 0.5 L, 0.2 L, and 0.1 L. The minimum concentration of active ingredient (a.i) of DFB required for a commercial product to contaminate at least 50% of oviposition sites was also investigated, along with the impact of other vector control methods, such as the removal/destruction of oviposition sites and the use of insecticides to kill adult 'females, on the auto-dissemination approach. The use of pure DFB compounds enabled contamination efficiency of more than 50% in oviposition sites with a volume of less than 2 L in scenarios with fewer oviposition sites. On the other hand, with the use of the commonly used concentration of the product, similar efficacy was only achieved in oviposition sites of 0.1 L and 0.2 L in medium and high infestation scenarios. Strategies that reduce the number of available oviposition sites work synergistically with the auto-dissemination strategy, making it possible to use less concentrated products and contaminated sites of larger volume. The strategy proved to be resilient in situations of insecticide application according to the concentration of DFB used, abundance of females, and low number of oviposition sites. Increasing the number of dissemination traps on the field also contributes to better results, especially for oviposition sites of 0.5 L and 1 L. The results of the model obtained under the stipulated conditions provide further support for the potential use of DFB as a substitute for PPF in the auto-dissemination strategy.

Insights from multigene analysis: first report of a Southeast Asian Mosquito, Aedes (Mucidus) laniger (Diptera: Culicidae) on Jeju Island from Korea

BACKGROUND

Certain mosquitoes are known as dominant vectors worldwide, and transmit infectious diseases. The expansion of mosquito habitats due to climate change and increased human activities poses a significant health threat by facilitating the spread of various non-native infectious diseases. This study focused on the detection of the Southeast Asian mosquito species, Aedes (Mucidus) laniger (Wiedemann, 1820) on Jeju Island, the southernmost region of the Republic of Korea (ROK), highlighting the potential risks associated with the spread of vector-borne diseases, particularly emphasizing the elevated likelihood of invasion by Southeast Asian mosquitoes.

METHODS

Field surveys were conducted in August 2023 on Jeju Island. Adult mosquitoes were collected using BG-sentinel traps and identified to the species level using taxonomic keys. Morphological and molecular analyses were employed to confirm species designations. Molecular data, including mitochondrial and nuclear genes, were used for phylogenetic analysis, which was performed to compare and identify among recorded subgenera in ROK. Species distribution modeling for Ae. laniger was performed to predict potential habitats using R package 'BIOMOD2'.

RESULTS

The two specimens of Ae. laniger were collected for the first time on Jeju Island. Morphological and molecular analyses confirmed the identity of this species within the subgenus Mucidus and validated the first record of this species in the ROK. We employed a simple multigene phylogenetic analysis to confirm a new mosquito record at the genus and subgenus levels, finally validating the consistency between morphological identification and molecular phylogenetic outcomes. Furthermore, we have updated the taxonomic keys for the genus Aedes in the ROK, and revised mosquito lists for Jeju Island, incorporating the inclusion of Ae. laniger. On the basis of species distribution modeling, the area of suitable habitat for Ae. laniger is expected to expand due to climate change, but this change did not appear to be meaningful in East Asia.

CONCLUSIONS

This case offers the first report of the Southeast Asian mosquito, Ae. laniger, in the ROK. The detection of this species on Jeju Island suggests the potential establishment of a breeding population their habitat and raises concerns about further expansion into the Korean Peninsula. Considering the annual occurrence of mosquito-borne disease cases in the Southeast Asia, it is essential to conduct monitoring not only in Jeju Island, where Ae. laniger has been identified, but also across the entire Korean Peninsula.

Pseudomonas mosselii: a potential alternative for managing pyrethroid-resistant Aedes aegypti

BACKGROUND

Aedes aegypti is a widespread mosquito in tropical and subtropical regions that causes significant mortality and morbidity in humans by transmitting diseases, such as dengue fever and Zika virus disease. Synthetic insecticides, such as pyrethroids, have been used to control Ae. aegypti, but these insecticides can also affect nontarget organisms and contaminate soil and water. This study aimed to investigate the mosquitocidal activity of Pseudomonas mosselii isolated from pond sludge against larvae of Ae. aegypti.

RESULTS

Based on the initial results, similar time-course profiles were obtained for the mosquitocidal activity of the bacterial culture and its supernatant, and the pellet resuspended in Luria-Bertani (LB) medium also showed delayed toxicity. These results imply that the toxic component can be released into the medium from live bacteria. Further research indicated that the toxic component appeared in the supernatant approximately 4 h after a 3-mL stock was cultured in 200 mL of LB medium. The stabilities of the P. mosselii culture and supernatant stored at different temperatures were also evaluated, and the best culture stability was obtained at 28 °C and supernatant stability at 4 °C. The bacterial culture and supernatant were toxic to larvae and pupae of not only susceptible Ae. aegypti but also pyrethroid-resistant strains.

CONCLUSION

This study highlights the value of the mosquitocidal activity of P. mosselii, which has potential as an alternative insecticide to control pyrethroid-resistant Ae. aegypti in the field. © 2024 Society of Chemical Industry.

Activation of the G protein-coupled sulfakinin receptor inhibits blood meal intake in the mosquito Aedes aegypti

Little is known about the blood-feeding physiology of arbovirus vector Aedes aegypti although this type of mosquito is known to transmit infectious diseases dengue, Zika, yellow fever, and chikungunya. Blood feeding in the female A. aegypti mosquito is essential for egg maturation and for transmission of disease agents between human subjects. Here, we identify the A. aegypti sulfakinin receptor gene SKR from the A. aegypti genome and show that SKR is expressed at different developmental stages and in varied anatomical localizations in the adult mosquito (at three days after eclosion), with particularly high expression in the CNS. Knockingdown sulfakinin and sulfakinin receptor gene expression in the female A. aegypti results in increased blood meal intake, but microinjection in the thorax of the sulfakinin peptide 1 and 2 both inhibits dose dependently blood meal intake (and delays the time course of blood intake), which is reversible with receptor antagonist. Sulfakinin receptor expressed ectopically in mammalian cells CHO-K1 responds to sulfakinin stimulation with persistent calcium spikes, blockable with receptor antagonist. These data together suggest that activation of the Gq protein-coupled (i.e., calcium-mobilizing) sulfakinin receptor inhibits blood meal intake in female A. aegypti mosquitoes and could serve as a strategic node for the future control of A. aegypti mosquito reproduction/population and disease transmission.

Intra-Phenotypic and -Genotypic Variations of Beauveria bassiana (Bals.) Vuill. Strains Infecting Aedes aegypti L. Adults

Beauveria bassiana has potential for Aedes aegypti biological control. However, its efficacy depends on the strain's geographic location, host susceptibility, and virulence. The present study aimed to evaluate the effectiveness of B. bassiana strain BBPTG4 conidia in controlling Ae. aegypti adults and its detection via introns profile on exposed mosquito corpses. Morphologic characteristics among strains were highly similar. Comprehensive testing of these strains demonstrated that BBPT4 exhibited the ideal biological activity for Ae. aegypti control, with a median lethal time (TL50) of 7.5 d compared to ~3 d and ~10 d for BB01 and BB37 strains, respectively. Infected mosquitoes died after GHA and BBPTG4 exposure, and corpses were analyzed for infecting strains detection. Differences among the seven evaluated strains were determined, assessing five different insertion group I intron profiles in BBTG4, BB01, GHA, BB37, and BB02 strains. Mosquitoes infected by BBPTG4 and non-exposed (negative control) intron profiles were obtained. We detected the presence of introns in the BBPTG4 strain, which were not present in non-exposed mosquitoes. In conclusion, B. bassiana strains showed similarities in terms of their cultural and microscopic morphological characteristics and biologicals virulence level, but different intron profiles. BBPTG4 strain-infected Ae. aegypti adult corpses, showing specific amplicons, enabled us to identify B. bassiana at the strain level among infected mosquitoes. However, monitoring and detection of field-infected insects is essential for further verification.

Aedes (Ochlerotatus) scapularis, Aedes japonicus japonicus, and Aedes (Fredwardsius) vittatus (Diptera: Culicidae): Three Neglected Mosquitoes with Potential Global Health Risks

More than 3550 species of mosquitoes are known worldwide, and only a fraction is involved in the transmission of arboviruses. Mosquitoes in sylvatic and semi-sylvatic habitats may rapidly adapt to urban parks and metropolitan environments, increasing human contact. Many of these mosquitoes have been found naturally infected with arboviruses from the Alphaviridae, Flaviviridae, and Bunyaviridae families, with many being the cause of medically important diseases. However, there is a gap in knowledge about the vector status of newly invasive species and their potential threat to human and domestic animal populations. Due to their rapid distribution, adaptation to urban environments, and anthropophilic habits, some neglected mosquito species may deserve more attention regarding their role as secondary vectors. Taking these factors into account, we focus here on Aedes (Ochlerotatus) scapularis (Rondani), Aedes japonicus japonicus (Theobald), and Aedes (Fredwardsius) vittatus (Bigot) as species that have the potential to become important disease vectors. We further discuss the importance of these neglected mosquitoes and how factors such as urbanization, climate change, and globalization profoundly alter the dynamics of disease transmission and may increase the participation of neglected species in propagating diseases.

Exploring fine-scale urban landscapes using satellite data to predict the distribution of Aedes mosquito breeding sites

BACKGROUND

The spread of mosquito-transmitted diseases such as dengue is a major public health issue worldwide. The Aedes aegypti mosquito, a primary vector for dengue, thrives in urban environments and breeds mainly in artificial or natural water containers. While the relationship between urban landscapes and potential breeding sites remains poorly understood, such a knowledge could help mitigate the risks associated with these diseases. This study aimed to analyze the relationships between urban landscape characteristics and potential breeding site abundance and type in cities of French Guiana (South America), and to evaluate the potential of such variables to be used in predictive models.

METHODS

We use Multifactorial Analysis to explore the relationship between urban landscape characteristics derived from very high resolution satellite imagery, and potential breeding sites recorded from in-situ surveys. We then applied Random Forest models with different sets of urban variables to predict the number of potential breeding sites where entomological data are not available.

RESULTS

Landscape analyses applied to satellite images showed that urban types can be clearly identified using texture indices. The Multiple Factor Analysis helped identify variables related to the distribution of potential breeding sites, such as buildings class area, landscape shape index, building number, and the first component of texture indices. Models predicting the number of potential breeding sites using the entire dataset provided an R² of 0.90, possibly influenced by overfitting, but allowing the prediction over all the study sites. Predictions of potential breeding sites varied highly depending on their type, with better results on breeding sites types commonly found in urban landscapes, such as containers of less than 200 L, large volumes and barrels. The study also outlined the limitation offered by the entomological data, whose sampling was not specifically designed for this study. Model outputs could be used as input to a mosquito dynamics model when no accurate field data are available.

CONCLUSION

This study offers a first use of routinely collected data on potential breeding sites in a research study. It highlights the potential benefits of including satellite-based characterizations of the urban environment to improve vector control strategies.

Imidazolium salt's toxic effects in larvae and cells of Aedes aegypti and Aedes albopictus (Diptera: Culicidae)

Aedes aegypti and Aedes albopictus are the main vectors of arboviruses such as Dengue, Chikungunya and Zika, causing a major impact on global economic and public health. The main way to prevent these diseases is vector control, which is carried out through physical and biological methods, in addition to environmental management. Although chemical insecticides are the most effective strategy, they present some problems such as vector resistance and ecotoxicity. Recent research highlights the potential of the imidazolium salt "1-methyl-3-octadecylimidazolium chloride" (C18MImCl) as an innovative and environmentally friendly solution against Ae. aegypti. Despite its promising larvicidal activity, the mode of action of C18MImCl in mosquito cells and tissues remains unknown. This study aimed to investigate its impacts on Ae. aegypti larvae and three cell lines of Ae. aegypti and Ae. albopictus, comparing the cellular effects with those on human cells. Cell viability assays and histopathological analyses of treated larvae were conducted. Results revealed the imidazolium salt's high selectivity (> 254) for mosquito cells over human cells. After salt ingestion, the mechanism of larval death involves toxic effects on midgut cells. This research marks the first description of an imidazolium salt's action on mosquito cells and midgut tissues, showcasing its potential for the development of a selective and sustainable strategy for vector control.

Evaluation of Multiple RNA Extraction Protocols for Chikungunya Virus Screening in Aedes aegypti Mosquitoes

Chikungunya virus (Togaviridae, Alphavirus; CHIKV) is a mosquito-borne global health threat. The main urban vector of CHIKV is the Aedes aegypti mosquito, which is found throughout Brazil. Therefore, it is important to carry out laboratory tests to assist in the virus's diagnosis and surveillance. Most molecular biology methodologies use nucleic acid extraction as the first step and require quality RNA for their execution. In this context, four RNA extraction protocols were evaluated in Ae. aegypti experimentally infected with CHIKV. Six pools were tested in triplicates (n = 18), each containing 1, 5, 10, 20, 30, or 40 mosquitoes per pool (72 tests). Four commercial kits were compared: QIAamp®, Maxwell®, PureLink®, and PureLink® with TRIzol®. The QIAamp® and PureLink® with TRIzol® kits had greater sensitivity. Two negative correlations were observed: as the number of mosquitoes per pool increases, the Ct value decreases, with a higher viral load. Significant differences were found when comparing the purity and concentration of RNA. The QIAamp® protocol performed better when it came to lower Ct values and higher RNA purity and concentration. These results may provide help in CHIKV entomovirological surveillance planning.

Gene silencing in the aedine cell lines C6/36 and U4.4 using long double-stranded RNA

BACKGROUND

RNA interference (RNAi) is a target-specific gene silencing method that can be used to determine gene functions and investigate host-pathogen interactions, as well as facilitating the development of ecofriendly pesticides. Commercially available transfection reagents (TRs) can improve the efficacy of RNAi. However, we currently lack a product and protocol for the transfection of insect cell lines with long double-stranded RNA (dsRNA).

METHODS

We used agarose gel electrophoresis to determine the capacity of eight TRs to form complexes with long dsRNA. A CellTiter-Glo assay was then used to assess the cytotoxicity of the resulting lipoplexes. We also measured the cellular uptake of dsRNA by fluorescence microscopy using the fluorophore Cy3 as a label. Finally, we analyzed the TRs based on their transfection efficacy and compared the RNAi responses of Aedes albopictus C6/36 and U4.4 cells by knocking down an mCherry reporter Semliki Forest virus in both cell lines.

RESULTS

The TRs from Biontex (K4, Metafectene Pro, and Metafectene SI+) showed the best complexing capacity and the lowest dsRNA:TR ratio needed for complete complex formation. Only HiPerFect was unable to complex the dsRNA completely, even at a ratio of 1:9. Most of the complexes containing mCherry-dsRNA were nontoxic at 2 ng/µL, but Lipofectamine 2000 was toxic at 1 ng/µL in U4.4 cells and at 2 ng/µL in C6/36 cells. The transfection of U4.4 cells with mCherry-dsRNA/TR complexes achieved significant knockdown of the virus reporter. Comparison of the RNAi response in C6/36 and U4.4 cells suggested that C6/36 cells lack the antiviral RNAi response because there was no significant knockdown of the virus reporter in any of the treatments.

CONCLUSIONS

C6/36 cells have an impaired RNAi response as previously reported. This investigation provides valuable information for future RNAi experiments by showing how to mitigate the adverse effects attributed to TRs. This will facilitate the judicious selection of TRs and transfection conditions conducive to RNAi research in mosquitoes.

Mechanisms of Flavivirus Cross-Protection against Yellow Fever in a Mouse Model

The complete lack of yellow fever virus (YFV) in Asia, and the lack of urban YFV transmission in South America, despite the abundance of the peridomestic mosquito vector Aedes (Stegomyia.) aegypti is an enigma. An immunologically naïve population of over 2 billion resides in Asia, with most regions infested with the urban YF vector. One hypothesis for the lack of Asian YF, and absence of urban YF in the Americas for over 80 years, is that prior immunity to related flaviviruses like dengue (DENV) or Zika virus (ZIKV) modulates YFV infection and transmission dynamics. Here we utilized an interferon α/β receptor knock-out mouse model to determine the role of pre-existing dengue-2 (DENV-2) and Zika virus (ZIKV) immunity in YF virus infection, and to determine mechanisms of cross-protection. We utilized African and Brazilian YF strains and found that DENV-2 and ZIKV immunity significantly suppresses YFV viremia in mice, but may or may not protect relative to disease outcomes. Cross-protection appears to be mediated mainly by humoral immune responses. These studies underscore the importance of re-assessing the risks associated with YF outbreak while accounting for prior immunity from flaviviruses that are endemic.

The effect of artificial light at night (ALAN) on the characteristics of diapause of Aedes albopictus

BACKGROUND

Recently, the effect of artificial light at night (ALAN) on the physiology and behavior of insects has gradually attracted the attention of researchers and has become a new research topic. Aedes albopictus is an important vector that poses a great public health risk. Further studies on the diapause of Ae. albopictus can provide a basis for new vector control, and it is also worth exploring whether the effect of ALAN on the diapause of Ae. albopictus will provide a reference for the prevention and control of infectious diseases mediated by Ae. albopictus.

METHODS

In this study, we experimentally studied the diapause characteristics of different geographical strains of Ae. albopictus under the interference of ALAN, explored the effect of ALAN on the diapause of Ae. albopictus and explored the molecular mechanism of ALAN on the diapause process through RNA-seq.

RESULTS

As seen from the diapause incidence, Ae. albopictus of the same geographic strain showed a lower diapause incidence when exposed to ALAN. The differentially expressed genes (DEGs) were mainly enriched in signaling and metabolism-related pathways in the parental females and diapause eggs of the ALAN group.

CONCLUSIONS

ALAN inhibits Ae. albopictus diapause. In the short photoperiod induced diapause of Ae. albopictus in temperate strain Beijing and subtropical strain Guangzhou, the disturbance of ALAN reduced the egg diapause rate and increased the egg hatching rate of Ae. albopictus, and the disturbance of ALAN also shortened the life cycle of Ae. albopictus eggs after hatching.

An evolutionarily conserved ubiquitin ligase drives infection and transmission of flaviviruses

Mosquito-borne flaviviruses such as dengue (DENV) and Zika (ZIKV) cause hundreds of millions of infections annually. The single-stranded RNA genome of flaviviruses is translated into a polyprotein, which is cleaved equally into individual functional proteins. While structural proteins are packaged into progeny virions and released, most of the nonstructural proteins remain intracellular and could become cytotoxic if accumulated over time. However, the mechanism by which nonstructural proteins are maintained at the levels optimal for cellular fitness and viral replication remains unknown. Here, we identified that the ubiquitin E3 ligase HRD1 is essential for flaviviruses infections in both mammalian hosts and mosquitoes. HRD1 directly interacts with flavivirus NS4A and ubiquitylates a conserved lysine residue for ER-associated degradation. This mechanism avoids excessive accumulation of NS4A, which otherwise interrupts the expression of processed flavivirus proteins in the ER. Furthermore, a small-molecule inhibitor of HRD1 named LS-102 effectively interrupts DENV2 infection in both mice and Aedes aegypti mosquitoes, and significantly disturbs DENV transmission from the infected hosts to mosquitoes owing to reduced viremia. Taken together, this study demonstrates that flaviviruses have evolved a sophisticated mechanism to exploit the ubiquitination system to balance the homeostasis of viral proteins for their own advantage and provides a potential therapeutic target to interrupt flavivirus infection and transmission.

An optical system to detect, surveil, and kill flying insect vectors of human and crop pathogens

Sustainable and effective means to control flying insect vectors are critically needed, especially with widespread insecticide resistance and global climate change. Understanding and controlling vectors requires accurate information about their movement and activity, which is often lacking. The Photonic Fence (PF) is an optical system that uses machine vision, infrared light, and lasers to identify, track, and interdict vectors in flight. The PF examines an insect's outline, flight speed, and other flight parameters and if these match those of a targeted vector species, then a low-power, retina-safe laser kills it. We report on proof-of-concept tests of a large, field-sized PF (30 mL × 3 mH) conducted with Aedes aegypti, a mosquito that transmits dangerous arboviruses, and Diaphorina citri, a psyllid which transmits the fatal huanglongbing disease of citrus. In tests with the laser engaged, < 1% and 3% of A. aegypti and D. citri, respectfully, were recovered versus a 38% and 19% recovery when the lacer was silenced. The PF tracked, but did not intercept the orchid bee, Euglossa dilemma. The system effectively intercepted flying vectors, but not bees, at a distance of 30 m, heralding the use of photonic energy, rather than chemicals, to control flying vectors.

Mosquito immune cells enhance dengue and Zika virus dissemination in Aedes aegypti

Mosquito-borne viruses cause more than 400 million annual infections and place over half of the world's population at risk. Despite this importance, the mechanisms by which arboviruses infect the mosquito host and disseminate to tissues required for transmission are not well understood. Here, we provide evidence that mosquito immune cells, known as hemocytes, play an integral role in the dissemination of dengue virus (DENV) and Zika virus (ZIKV) in the mosquito Aedes aegypti. We establish that phagocytic hemocytes are a focal point for virus infection and demonstrate that these immune cell populations facilitate virus dissemination to the ovaries and salivary glands. Additional transfer experiments confirm that virus-infected hemocytes confer a virus infection to non-infected mosquitoes more efficiently than free virus in acellular hemolymph, revealing that hemocytes are an important tropism to enhance virus dissemination in the mosquito host. These data support a "trojan horse" model of virus dissemination where infected hemocytes transport virus through the hemolymph to deliver virus to mosquito tissues required for transmission and parallels vertebrate systems where immune cell populations promote virus dissemination to secondary sites of infection. In summary, this study significantly advances our understanding of virus infection dynamics in mosquitoes and highlights conserved roles of immune cells in virus dissemination across vertebrate and invertebrate systems.

The potential habitat and environmental fitness change of Aedes albopictus in Western Eurasia for 2081-2100

BACKGROUND OBJECTIVES

The range of Aedes albopictus, the most important vector mosquito in Western Eurasia is growing due to climate change. However, it is not known how it will influence the habitats occupied by the species and its environmental fitness within its future range.

METHODS

To study this question, the habitat characteristic of the mosquito was investigated for 2081-2100.

RESULTS

The models suggest a notable future spread of the mosquito in the direction of Northern Europe and the parallel northward and westward shift of the southern and eastern potential occurrences of the mosquito. The models suggest a notable increase in generation numbers in the warmest quarter, which can reach 4-5 generations in the peri-Mediterranean region. However, both the joint survival rate of larvae and pupae and the number of survival days of adults in the warmest quarter exhibit decreasing values, as does the potential disappearance of the mosquito in the southern regions of Europe and Asia Minor, along with the growing atmospheric CO2 concentration-based scenarios.

INTERPRETATION CONCLUSION

While in 1970-2000 Aedes albopictus mainly occupied the hot and warm summer temperate regions of Europe, the species will inhabit dominantly the cool summer temperate (oceanic) and the humid continental climate territories of North and North-Eastern Europe in 2081-2100.

Irritant and repellent behaviors of sterile male Aedes aegypti (L.) (Diptera: Culicidae) mosquitoes are crucial in the development of disease control strategies applying sterile insect technique

The mosquito Aedes aegypti, known to transmit important arboviral diseases, including dengue, chikungunya, Zika and yellow fever. Given the importance of this disease vector, a number of control programs have been proposed involving the use of the sterile insect technique (SIT). However, the success of this technique hinges on having a good understanding of the biology and behavior of the male mosquito. Behavioral responses of Ae. aegypti male populations developed for SIT technology were tested under laboratory conditions against chemical and natural irritants and repellents using an excito-repellency (ER) chamber. The results showed that there were no significant behavioral escape responses in any of the radiation-sterilized male Ae. aegypti test populations when exposed to citronella, DEET, transfluthrin, and deltamethrin, suggesting that SIT did not suppress the expected irritancy and repellency (avoidance) behaviors. The type of information reported in the current study is vital in defining the effects of SIT on vector behavior and understanding how such behavior may influence the success of SIT technology with regard to other vector control interventions.

Impact of SumiLarv® 2MR on Aedes aegypti larvae: a multicenter study in Brazil

BACKGROUND

Aedes aegypti is associated with dengue, Zika, and chikungunya transmission. These arboviruses are responsible for national outbreaks with severe public health implications. Vector control is one of the tools used to prevent mosquito proliferation, and SumiLarv® 2MR is an alternative commercial product based on pyriproxyfen for larval/pupal control. In this study, the residual effectiveness of SumiLarv® 2MR in different regions of Brazil was evaluated in simulated field conditions.

METHODS

We conducted a multicenter study across four Brazilian states-Amapá, Pernambuco, Rio de Janeiro, and São Paulo-given the importance to the country's climatic variances in the north, northeast, and southeast regions and their influence on product efficiency. The populations of Ae. aegypti from each location were held in an insectary. Third-instar larvae (L3) were added every 2 weeks to water containers with SumiLarv® 2MR discs in 250-, 500- and 1000-l containers in Amapá and Rio de Janeiro, and 100-l containers in Pernambuco and São Paulo, using concentrations of 0.04, 0.08, and 0.16 mg/l.

RESULTS

Adult emergence inhibition over 420 days was observed in all tests conducted at a concentration of 0.16 mg/l; inhibition for 308-420 days was observed for 0.08 mg/l, and 224-420 days for 0.04 mg/l.

CONCLUSIONS

Sumilarv® 2MR residual activity demonstrated in this study suggests that this new pyriproxyfen formulation is a promising alternative for Aedes control, regardless of climatic variations and ideal concentration, since the SumiLarv® 2MR showed adult emergence inhibition of over 80% and residual activity greater than 6 months, a period longer than that recommended by the Ministry of Health of Brazil between product re-application in larval breeding sites.

Neochloris aquatica induces larval mortality, molting defects, and unstable flightless adults in the Asian tiger mosquito

The Asian tiger mosquito, Aedes albopictus, is a highly invasive and aggressive species capable of transmitting a large number of etiological agents of medical and veterinary importance, posing a high risk for the transmission of emerging viruses between animals and humans. In this work, we evaluated the mosquitocidal activity of Neochloris aquatica against A. albopictus throughout its development and analyzed whether this effect was potentiated when the microalga was cultivated under stress conditions due to nutrient deprivation. Our results suggest that N. aquatica produces metabolites that have negative effects on these insects, including larval mortality, interruption of pupal development, and incomplete emergence of adults when fed on microalgae in the larval stages. When microalgae were cultured under stress conditions, an increase in molting defects was recorded, and the number of healthy adults emerged drastically decreased. Histological studies revealed severe signs of total disintegration of different tissues and organs in the thorax and abdomen regions. The muscles and fat bodies in the midgut and foregut were severely distorted. In particular, larval intestinal tissue damage included vacuolization of the cytoplasm, destruction of brush border microvilli, and dilation of the intercellular space, which are distinctive morphological characteristics of apoptotic cells. Evidence suggests that N. aquatica produces metabolites with mosquitocidal effects that affect development and, therefore, the ability to vector etiological agents of medical and veterinary importance.

Effect of water salinity on immature performance and lifespan of adult Asian tiger mosquito

BACKGROUND

Aedes albopictus (Skuse, 1894) is a vector for pathogens like dengue, chikungunya, and Zika viruses. Its adaptive capacity enables reproduction in temperate climates and development mainly in artificial containers with fresh water in urbanized areas. Nevertheless, breeding in coastal areas may also occur along with its aggressive invasiveness. Global warming and the consequent rise in sea levels will increase saline (> 30 ppt) or brackish (0.5-30 ppt salt) water in coastal regions. To address whether Ae. albopictus can breed in brackish water, we initiated the current study that analyses the survival of immature stages at different salinity concentrations and explores whether carryover effects occur in the resulting adults. This possible adaptation is important when considering the potential for development in new habitats and expansion of one of the world's most invasive species.

METHODS

We investigated the influence of salinity on the survival of Ae. albopictus larvae and adults under laboratory-controlled conditions. First instar larvae were exposed to different salinity concentrations (0 to 30 ppt) and their development time, pupation, adult emergence, and overall survival were monitored daily. We used Kaplan-Meier and Cox regression models to analyze the survival rates at different salinity levels. Furthermore, life tables were constructed under each salinity concentration.

RESULTS

Increasing salt concentrations significantly increased the mortality risk during immature development, while no significant effect was observed on adult mortality risk. A comparison between distilled and bottled water revealed a notable increase in overall mortality risk for individuals developing in distilled water. However, no significant effects were found when analyzing survival from the first larval stage to adult emergence and adult lifespan. The life expectancy of immature stages decreased with increasing salt concentrations, although salinity concentration did not significantly impact adult life expectancy.

CONCLUSIONS

Our findings suggest that Ae. albopictus, previously considered freshwater species, can successfully develop and survive in brackish waters, even in the absence of characteristic structures found in euryhaline species. These adaptations may enable Ae. albopictus to establish new breeding sites and colonize unexplored territories. Knowledge of these physiological adaptations of Ae. albopictus to salinity should be pursued to increase the range of control of the species, and to make more accurate predictions of its dispersal and vectoring ability.

Entomological risk assessment for transmission of arboviral diseases by Aedes mosquitoes in a domestic and forest site in Accra, Ghana

Dengue, Zika and chikungunya are Aedes-borne viral diseases that have become great global health concerns in the past years. Several countries in Africa have reported outbreaks of these diseases and despite Ghana sharing borders with some of these countries, such outbreaks are yet to be detected. Viral RNA and antibodies against dengue serotype-2 have recently been reported among individuals in some localities in the regional capital of Ghana. This is an indication of a possible silent transmission ongoing in the population. This study, therefore, investigated the entomological transmission risk of dengue, Zika and chikungunya viruses in a forest and domestic population in the Greater Accra Region, Ghana. All stages of the Aedes mosquito (egg, larvae, pupae and adults) were collected around homes and in the forest area for estimation of risk indices. All eggs were hatched and reared to larvae or adults for morphological identification together with larvae and adults collected from the field. The forest population had higher species richness with 7 Aedes species. The predominant species of Aedes mosquitoes identified from both sites was Aedes aegypti (98%). Aedes albopictus, an important arbovirus vector, was identified only in the peri-domestic population at a prevalence of 1.5%, significantly higher than previously reported. All risk indices were above the WHO threshold except the House Index for the domestic site which was moderate (19.8). The forest population recorded higher Positive Ovitrap (34.2% vs 26.6%) and Container (67.9% vs 36.8%) Indices than the peri-domestic population. Although none of the mosquito pools showed the presence of dengue, chikungunya or Zika viruses, all entomological risk indicators showed that both sites had a high potential arboviral disease transmission risk should any of these viruses be introduced. Continuous surveillance is recommended in these and other sites in the Metropolis to properly map transmission risk areas to inform outbreak preparedness strategies.

Arbovirus surveillance in febrile patients attending selected health facilities in Rwanda

Arthropod-borne (arbo) viruses cause emerging diseases that affect the livelihoods of people around the world. They are linked to disease outbreaks resulting in high morbidity, mortality, and economic loss. In sub-Saharan Africa, numerous arbovirus outbreaks have been documented, but the circulation and magnitude of illness caused by these viruses during inter-epidemic periods remains unknown in many regions. In Rwanda, there is limited knowledge on the presence and distribution of arboviruses. This study aimed at determining the occurrence and distribution of selected arboviruses, i.e., chikungunya virus (CHIKV), o'nyong-nyong virus (ONNV), dengue virus (DENV), West Nile virus (WNV), Zika virus (ZIKV), Rift Valley fever virus (RVFV) and Crimean-Congo haemorrhagic fever virus (CCHFV), among febrile patients visiting health centres in Rwanda. A total of 2294 dry blood spots (DBS) were collected on filter papers during August 2019 - December 2020. Reverse-transcription polymerase chain reaction (RT-PCR) was performed on samples in pools of ten, using both quantitative (DENV, ZIKV, RVFV) and conventional PCR (CHIKV, ONNV, WNV, CCHFV) with virus specific primers, followed by sequencing. Demographic data and clinical manifestations of illness were analysed. ONNV infection was detected in 12 of 230 pools (5.2%) and ZIKV in three pools (1.3%). The other arboviruses were not detected. All ONNV cases were found in the Rwaniro health centre, while ZIKV infection was found among patients visiting the Kirinda and Zaza health centres. There was temporal variability in ONNV infections with most cases being recorded during the long dry season, while ZIKV infection occurred during both dry and wet seasons. Patients with ONNV were older and more were females. In conclusion, ONNV and ZIKV infection were detected in acute patients and can explain some of the feverish diseases in Rwanda.

Structure of the Lysinibacillus sphaericus Tpp49Aa1 pesticidal protein elucidated from natural crystals using MHz-SFX

The Lysinibacillus sphaericus proteins Tpp49Aa1 and Cry48Aa1 can together act as a toxin toward the mosquito Culex quinquefasciatus and have potential use in biocontrol. Given that proteins with sequence homology to the individual proteins can have activity alone against other insect species, the structure of Tpp49Aa1 was solved in order to understand this protein more fully and inform the design of improved biopesticides. Tpp49Aa1 is naturally expressed as a crystalline inclusion within the host bacterium, and MHz serial femtosecond crystallography using the novel nanofocus option at an X-ray free electron laser allowed rapid and high-quality data collection to determine the structure of Tpp49Aa1 at 1.62 Å resolution. This revealed the packing of Tpp49Aa1 within these natural nanocrystals as a homodimer with a large intermolecular interface. Complementary experiments conducted at varied pH also enabled investigation of the early structural events leading up to the dissolution of natural Tpp49Aa1 crystals-a crucial step in its mechanism of action. To better understand the cooperation between the two proteins, assays were performed on a range of different mosquito cell lines using both individual proteins and mixtures of the two. Finally, bioassays demonstrated Tpp49Aa1/Cry48Aa1 susceptibility of Anopheles stephensi, Aedes albopictus, and Culex tarsalis larvae-substantially increasing the potential use of this binary toxin in mosquito control.

Behavioral Changes of Some Arboviral Vectors in Zika Forest: A Concern for Emerging and Re-Emerging Diseases in Uganda

Background: The increasing reports on emerging/re-emerging arboviral disease outbreaks or epidemics in Sub-Saharan Africa have been impacted by factors, including the changing climate plus human activities that have resulted in land cover changes. These factors influence the prevalence, incidence, behavior, and distribution of vectors and vector-borne diseases. In this study, we assessed the potential effect of land cover changes on the distribution and oviposition behavior of some arboviral vectors in Zika forest, Uganda, which has decreased by an estimated 7 hectares since 1952 due to an increase in anthropogenic activities in the forest and its periphery. Materials and Methods: Immature mosquitoes were collected using bamboo pots and placed at various levels of a steel tower in the forest and at different intervals from the forest periphery to areas among human dwellings. Collections were conducted for 20 months. Results and Conclusion: Inside the forest, 22,280 mosquitoes were collected belonging to four arboviral vectors: Aedes aegypti, Aedes africanus, Aedes apicoargenteus, and Aedes cumminsii. When compared with similar studies conducted in the forest in 1964, there was a change from a sylvatic to a tendency of peridomestic behavior in A. africanus, which was now collected among human dwellings. There was an unexpected change in the distribution of A. aegypti, which was not only collected outside the forest as in previous reports but also collected in the forest. Conversely, A. cumminsii originally collected in the forest expanded its ranges with collections outside the forest in this study. Aedes simpsoni maintained its distribution range outside the forest among agricultural sites. We suspect that land cover changes were favorable to most of the arboviral vectors hence enhancing their proliferation and habitat range. This potentially increases the transmission of arboviral diseases in the area, hence impacting the epidemiology of emerging/remerging diseases in Uganda.

Identification of Aedes aegypti and Aedes albopictus eggs based on image processing and elliptic fourier analysis

Dengue hemorrhagic fever is a worldwide epidemic caused by dengue virus and spread by infected female mosquitoes. The two main mosquito species vectors of the dengue virus are Aedes aegypti and Aedes albopictus. Conventionally, the identification of these two species' egg is time-consuming which makes vector control more difficult. However, although attempts on efficiency improvements by providing automatic identification have been conducted, the earliest stage is at the larval stage. In addition, there are currently no studies on classifying to distinguish the two vectors during the egg stage based on their digital image. A total of 140 egg images of Aedes aegypti and Aedes albopictus were collected and validated by rearing them individually to become adult mosquitoes. Image processing and elliptic Fourier analysis were carried out to extract and describe the shape difference of the two vectors' eggs. Machine learning algorithms were then used to classify the shape signatures. Morphometrically, the two species' eggs were significantly different, which Aedes albopictus were smaller in size. Egg-shape contour reconstructions of principal components and Multivariate Analysis of Variance (MANOVA) revealed that there is a significant difference (p value [Formula: see text]) in shape between two species' eggs at the posterior end. Based on Wilk's lambda of the MANOVA results, the classification could be done using only the first 3 principal components. Classification of the test data yielded an accuracy of 85.00% and F1 score 84.21% with Linear Discriminant Analysis applying default hyperparameter. Alternatively, k-Nearest Neighbors with optimal hyperparameter yielded a higher classification result with 87.50% and 87.18% of accuracy and F1 score, respectively. These results demonstrate that the proposed method can be used to classify Aedes aegypti and Aedes albopictus eggs based on their digital image. This method provides a foundation for improving the identification and surveillance of the two vectors and decision making in developing vector control strategies.

Aedes albopictus salivary adenosine deaminase is an immunomodulatory factor facilitating dengue virus replication

The Asian tiger mosquito, Aedes albopictus, is an important vector for the transmission of arboviruses such as dengue virus (DENV). Adenosine deaminase (ADA) is a well-characterized metabolic enzyme involved in facilitating blood feeding and (or) arbovirus transmission in some hematophagous insect species. We previously reported the immunologic function of ADA by investigating its effect on mast cell activation and the interaction with mast cell tryptase and chymase. The 2-D gel electrophoresis and mass spectrometry analysis in the current study revealed that ADA is present and upregulated following mosquito blood feeding, as confirmed by qRT-PCR and western blot. In addition, the recombinant ADA efficiently converted adenosine to inosine. Challenging the Raw264.7 and THP-1 cells with recombinant ADA resulted in the upregulation of IL-1β, IL-6, TNF-α, CCL2, IFN-β, and ISG15. The current study further identified recombinant ADA as a positive regulator in NF-κB signaling targeting TAK1. It was also found that recombinant Ae. albopictus ADA facilitates the replication of DENV-2. Compared with cells infected by DENV-2 alone, the co-incubation of recombinant ADA with DENV-2 substantially increased IL-1β, IL-6, TNF-α, and CCL2 gene transcripts in Raw264.7 and THP-1 cells. However, the expression of IFN-β and ISG15 were markedly downregulated in Raw264.7 cells but upregulated in THP-1 cells. These findings suggest that the immunomodulatory protein, Ae. albopictus ADA is involved in mosquito blood feeding and may modulate DENV transmission via macrophage or monocyte-driven immune response.

Aedes albopictus microbiota: Differences between wild and mass-reared immatures do not suggest negative impacts from a diet based on black soldier fly larvae and fish food

The "Sterile Insect Technique" (SIT), a promising method to control Aedes albopictus, the Asian tiger mosquito, is gaining increasing interest. Recently, the role of microbiota in mosquito fitness received attention, but the link between microbiota and larval diet in mass rearing programs for SIT remains largely unexplored. We characterized the microbiota of four larval instars, pupae and eggs of non-wild (NW) lab-reared Ae. albopictus fed with a diet based on Black soldier fly (Hermetia illucens) larvae powder and fish food KOI pellets. We compared it with wild (W) field-collected individuals and the bacterial community occurring in rearing water-diet (DIET). A total of 18 bacterial classes with > 0.10% abundance were found overall in the samples, with seven classes being especially abundant. Overall, the microbiota profile significantly differed among NW, W and DIET. Verrucomicrobiae were significantly more abundant in W and DIET, Bacteroidia were more abundant in NW and DIET, and Gammaproteobacteria were only more abundant in W than in DIET. W-eggs microbiota differed from all the other groups. Large differences also appeared at the bacterial genus-level, with the abundance of 14 genera differing among groups. Three ASVs of Acinetobacter, known to have positive effects on tiger mosquitoes, were more abundant in NW than in W, while Serratia, known to have negative or neutral effects on another Aedes species, was less abundant in NW than in W. The bacterial community of W-eggs was the richest in species, while dominance and diversity did not differ among groups. Our data show that the diet based on Black soldier fly powder and fish food KOI influences the microbiota of NW tiger mosquito immature stages, but not in a way that may suggest a negative impact on their quality in SIT programs.

Evolution of knockdown resistance (kdr) mutations of Aedes aegypti and Aedes albopictus in Hainan Island and Leizhou Peninsula, China

Background

Aedes aegypti and Aedes albopictus are important vectors of human arboviruses, transmitting arboviral diseases such as yellow fever, dengue, chikungunya and Zika. These two mosquitoes coexist on Hainan Island and the Leizhou Peninsula in China. Over the past 40 years, the distribution of Ae. albopictus has gradually expanded in these areas, while the distribution of Ae. aegypti has declined dramatically mainly due to the ecological changes and some other factors such as heavy use of insecticide indoor based on endophagic bloodfeeding of the species.

Methods

This study focused on the knockdown resistance (kdr) genes of both mosquitoes, investigated their mutations, and analyzed their haplotype and evolutionary diversity combined with population genetic features based on the ND4/ND5 genes to further elucidate the molecular mechanisms underlying the development of insecticide resistance in both mosquitoes.

Results

Three mutations, S989P, V1016G and F1534C, were found to be present in Ae. aegypti populations, and the three mutations occurred synergistically. Multiple mutation types (F1534C/S/L/W) of the F1534 locus are found in Ae. albopictus populations, with the three common mutations F1534C, F1534S and F1534L all having multiple independent origins. The F1534W (TTC/TGG) mutation is thought to have evolved from the F1534L (TTC/TTG) mutation. The F1534S (TTC/TCG) mutation has evolved from the F1534S (TTC/TCC) mutation. The most common form of mutation at the F1534 locus found in this study was S1534C, accounting for 20.97%, which may have evolved from the F1534C mutation. In addition, a new non-synonymous mutation M1524I and 28 synonymous mutations were identified in Ae. albopictus populations. Correlation analysis showed that the genetic diversity of Ae. aegypti and Ae. albopictus populations did not correlate with their kdr haplotype diversity (P>0.05), but strong gene flow between populations may have contributed to the evolution of the kdr gene.

Conclusion

The study of kdr gene evolution in the two mosquito species may help to identify the evolutionary trend of insecticide resistance at an early stage and provide a theoretical basis for improving the efficiency of biological vector control and subsequent research into new insecticides.

First report of Aedes albopictus (Diptera: Culicidae) in the North of Colombia

Aedes albopictus is considered a potential vector of arboviruses in Colombia. Females and males naturally infected with dengue, Zika and chikungunya viruses have already been found in this country. We document the first record of Ae. albopictus in the Cordoba department, in North of Colombia. The finding was carried out during Ae. aegypti collection activities in the Ayapel, Montelibano, Planeta Rica, Pueblo Nuevo and Puerto Libertador municipalities. The entomological material was collected in water containers such as cement water tanks, tanks, bottles, tires, abandoned toilets, and plastic lids with natural water located in the intradomicile, peridomicile, and extra-domicile spaces of the homes. We collected 658 Ae. albopictus samples in the larva and pupa stages, and once these reached adulthood, we determined that 389 were female and 269 were male. This is the first record of the presence of Ae. albopictus in the Cordoba department.

Distribution and Abundance of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in Benin, West Africa

Updated information on the distribution and abundance of Aedes aegypti and Aedes albopictus is crucial to prepare African countries, such as Benin, for possible arboviral disease outbreaks. This study aims to evaluate the geographical distribution, abundance and biting behaviour of these two vectors in Benin. Three sampling techniques were used in this study. The collection of Aedes spp. adults were made through human landing catch (HLC), immatures were captured with the use of ovitraps, and a dipping technique was used for the collection of Aedes spp. in 23 communes located along the North-South and East-West transect of Benin. Adult Aedes mosquitoes were collected indoors and outdoors using HLC. Mosquito eggs, larvae and pupae were collected from containers and ovitraps. The adult mosquitoes were morphologically identified, then confirmed using a polymerase chain reaction (PCR). Overall, 12,424 adult specimens of Aedes spp. were collected, out of which 76.53% (n = 9508) and 19.32% (n = 2400) were morphologically identified as Ae. aegypti and Ae. albopictus, respectively. Geographically, Ae. aegypti was found across the North-South transect unlike Ae. albopictus, which was only encountered in the southern part of the country, with a great preponderance in Avrankou. Furthermore, an exophagic behaviour was observed in both vectors. This updated distribution of Aedes mosquito species in Benin will help to accurately identify areas that are at risk of arboviral diseases and better plan for future vector control interventions.