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The mosquito microbiome significantly influences vector competence, including in Aedes albopictus, a globally invasive vector. Describing the microbiome and Wolbachia strains of Ae. albopictus from different regions can guide area-specific control strategies. Mosquito samples from Spain and São Tomé were analyzed using 16S rRNA gene sequencing and metagenomic sequencing. Wolbachia infection patterns were observed by sex and population. Female mosquitoes were blood-fed, a factor considered in analyzing their microbiota. Results revealed a dominance of dual Wolbachia infections, strains A and B, in the microbiome of both populations of Ae. albopictus, especially among females. Both populations shared a core microbiome, although 5 and 9 other genera were only present in Spain and São Tomé populations, respectively. Genera like Pelomonas and Nevskia were identified for the first time in Aedes mosquitoes. This study is the first to describe the Ae. albopictus bacteriome in Spain and São Tomé, offering insights for the development of targeted mosquito control strategies. Understanding the specific microbiome composition can help in designing more effective interventions, such as microbiome manipulation and Wolbachia-based approaches, to reduce vector competence and transmission potential of these mosquitoes. [ABSTRACT FROM AUTHOR]

Abstract Mosquito associated virus have always been a significant threat to global health. Metagenomics offers a straightforward and quantitative means to acquire the information of novel virus and has greatly enriched the content of mosquito associated virus databases. During an entomological surveillance for arthropod-borne viruses in China, we identified a previously unrecognized virus from mosquitoes, temporarily named Huajieling virus. In this study, a total of 3,960 mosquitoes were collected and then divided into 91 pools, according to location and species. QRT-PCR and nested PCR were performed to confirm the presence of Huajieling virus. Its genomic features and phylogenetic relationships were further analyzed. Our results showed that Huajieling virus was detected in 7 of the 91 mosquito pools and that the minimum infection rate (MIR) was 0.18% (7/3,960). One complete genome sequence and 2 viral partial sequences were obtained from the Huajieling virus-positive pools. Pairwise distances analysis indicated that these amplified sequences shared high nucleotide identity. Phylogenetic analysis demonstrated that Huajieling virus is most closely related to Wufeng shrew picorna-like virus 43, which belonging to Picornavirales. Further analyses indicated that Huajieling virus is a new member of unclassified Picornavirales, and is intermediate between the family Caliciviridae and Secoviridae in taxonomic status.

Abstract Humans have greatly altered earth’s terrestrial water cycle with the majority of fresh water being used for agriculture. Irrigation changes spatial and temporal water availability and alters mosquito abundance and phenology. Previous studies evaluating the effect of irrigation on mosquito abundance and mosquito-borne disease have shown inconsistent results and little is known about the effect of irrigation on variability in mosquito abundance. We examined the effect of irrigation, climate and land cover on mosquito abundance and human West Nile virus (WNV) disease cases across California. Irrigation made up nearly a third of total water inputs, and exceeded precipitation in some regions. Abundance of two key vectors of several arboviruses, including WNV, Culex tarsalis and the Culex pipiens complex, increased 17–21-fold with irrigation. Irrigation reduced seasonal variability in C. tarsalis abundance by 36.1%. Human WNV incidence increased with irrigation, which explained more than a third (34.2%) of the variation in WNV incidence among California counties. These results suggest that irrigation can increase and decouple mosquito populations from natural precipitation variability, resulting in sustained and increased disease burdens. Shifts in precipitation due to climate change are likely to result in increased irrigation in many arid regions which could increase mosquito populations and disease.

Insect growth regulators, like S-methoprene, are heavily relied upon worldwide for larval mosquito chemical control due to their target specificity and long-lasting effects. In this study, susceptibility to S-methoprene was evaluated in Culex pipiens, a globally important vector species. Populations from 14 sites throughout the Chicago area with a long history of S-methoprene use and two sites with minimal use in Wisconsin were examined. Using a bioassay methodology and probit analyses, LC50 and LC90 values were calculated and compared to a susceptible laboratory strain to develop resistance ratios, then categorized for resistance intensity. The resistance ratios observed required the addition of another category, termed 'extreme' resistance, indicating resistance ratios greater than 100. 'Low' to 'extreme' levels of resistance to S-methoprene were detected throughout Illinois populations, with resistance ratios ranging from 2.33 to 1010.52. Resistance was not detected in populations where S-methoprene pressure has been very limited. These 'extreme' resistance ratios observed have never been documented in a wild vector species mosquito population. The relationships between historical S-methoprene use, resistance detected with laboratory bioassays, and the potential for field product failure remain unclear. However, the profound resistance detected here demonstrates a potential critical threat to protecting public health from mosquito-borne diseases. [ABSTRACT FROM AUTHOR]

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

Arboviruses transmitted by mosquitoes, including Japanese encephalitis virus (JEV), present a substantial global health threat. JEV is transmitted by mosquitoes in the genus Culex, which are common in both urban and rural areas in Vietnam. In 2020, we conducted a 1-year survey of Culex mosquito abundance in urban, suburban, and peri-urban areas of Hanoi using CDC-light traps. Mosquitoes were identified to species and sorted into pools based on species, sex, and trap location. The mosquito pools were also investigated by RT-qPCR for detection of JEV. In total, 4829 mosquitoes were collected over a total of 455 trap-nights, across 13 months. Collected mosquitoes included Culex, Aedes, Anopheles, and Mansonia species. Culex mosquitoes, primarily Cx. quinquefasciatus, predominated, especially in peri-urban areas. Most Culex mosquitoes were caught in the early months of the year. The distribution and abundance of mosquitoes exhibited variations across urban, suburban, and peri-urban sites, emphasizing the influence of environmental factors such as degree of urbanization, temperature and humidity on Culex abundance. No JEV was detected in the mosquito pools. This study establishes baseline knowledge of Culex abundance and temporal variation, which is crucial for understanding the potential for JEV transmission in Hanoi. [ABSTRACT FROM AUTHOR]

Ivermectin (IVM) has been proposed as a new tool for malaria control as it is toxic on vectors feeding on treated humans or cattle. Nevertheless, IVM may have a direct mosquitocidal effect when applied on bed nets or sprayed walls. The potential for IVM application as a new insecticide for long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) was tested in this proof-of-concept study in a laboratory and semi-field environment. Laboratory-reared, insecticide-susceptible Kisumu Anopheles gambiae were exposed to IVM on impregnated netting materials and sprayed plastered- and mud walls using cone bioassays. The results showed a direct mosquitocidal effect of IVM on this mosquito strain as all mosquitoes died by 24 h after exposure to IVM. The effect was slower on the IVM-sprayed walls compared to the treated nettings. Further work to evaluate possibility of IVM as a new insecticide formulation in LLINs and IRS will be required. [ABSTRACT FROM AUTHOR]

Wolbachia bacteria are common endosymbionts of insects and have recently been applied for controlling arboviral vectors, especially Aedes aegypti mosquito populations. However, several medically important mosquito species in Sri Lanka were present with limited information for the Wolbachia infection status. Therefore, the screening of Wolbachia in indigenous mosquitoes is required prior to a successful application of Wolbachia-based vector control strategy. In this study, screening of 78 mosquito species collected from various parts of the country revealed that 13 species were positive for Wolbachia infection, giving ~ 17% infection frequency of Wolbachia among the Sri Lankan mosquitoes. Twelve Wolbachia-positive mosquito species were selected for downstream Wolbachia strain genotyping using Multi Locus Sequencing Type (MLST), wsp gene, and 16S rRNA gene-based approaches. Results showed that these Wolbachia strains clustered together with the present Wolbachia phylogeny of world mosquito populations with some variations. Almost 90% of the mosquito populations were infected with supergroup B while the remaining were infected with supergroup A. A new record of Wolbachia supergroup B infection in Ae. aegypti, the main vectors of dengue, was highlighted. This finding was further confirmed by real-time qPCR, revealing Wolbachia density variations between Ae. aegypti and Ae. albopictus (p = 0.001), and between males and females (p < 0.05). The evidence of natural Wolbachia infections in Ae. aegypti populations in Sri Lanka is an extremely rare incident that has the potential to be used for arboviral vector control. [ABSTRACT FROM AUTHOR]

The intention-to-treat (ITT) analysis of the Applying Wolbachia to Eliminate Dengue (AWED) trial estimated a protective efficacy of 77.1% for participants resident in areas randomised to receive releases of wMel-infected Aedes aegypti mosquitoes, an emerging dengue preventive intervention. The limiting assumptions of ITT analyses in cluster randomised trials and the mobility of mosquitoes and humans across cluster boundaries indicate the primary analysis is likely to underestimate the full public health benefit. Using spatiotemporally-resolved data on the distribution of Wolbachia mosquitoes and on the mobility of AWED participants (n = 6306), we perform complier-restricted and per-protocol re-examinations of the efficacy of the Wolbachia intervention. Increased intervention efficacy was estimated in all analyses by the refined exposure measures. The complier-restricted analysis returned an estimated efficacy of 80.7% (95% CI 65.9, 89.0) and the per-protocol analysis estimated 82.7% (71.7, 88.4) efficacy when comparing participants with an estimated wMel exposure of ≥ 80% compared to those with <20%. These reanalyses demonstrate how human and mosquito movement can lead to underestimation of intervention effects in trials of vector interventions and indicate that the protective efficacy of Wolbachia is even higher than reported in the primary trial results. [ABSTRACT FROM AUTHOR]

Chikungunya virus (CHIKV) poses a significant global health threat, re-emerging as a mosquito-transmitted pathogen that caused high fever, rash, and severe arthralgia. In Thailand, a notable CHIKV outbreak in 2019–2020 affected approximately 20,000 cases across 60 provinces, underscoring the need for effective mosquito control protocols. Previous studies have highlighted the role of midgut bacteria in the interaction between mosquito vectors and pathogen infections, demonstrating their ability to protect the insect from invading pathogens. However, research on the midgut bacteria of Aedes (Ae.) aegypti, the primary vector for CHIKV in Thailand remains limited. This study aims to characterize the bacterial communities in laboratory strains of Ae. aegypti, both infected and non-infected with CHIKV. Female mosquitoes from a laboratory strain of Ae. aegypti were exposed to a CHIKV-infected blood meal through membrane feeding, while the control group received a non-infected blood meal. At 7 days post-infection (dpi), mosquito midguts were dissected for 16S rRNA gene sequencing to identify midgut bacteria, and CHIKV presence was confirmed by E1-nested RT-PCR using mosquito carcasses. The study aimed to compare the bacterial communities between CHIKV-infected and non-infected groups. The analysis included 12 midgut bacterial samples, divided into three groups: CHIKV-infected (exposed and infected), non-infected (exposed but not infected), and non-exposed (negative control). Alpha diversity indices and Bray–Curtis dissimilarity matrix revealed significant differences in bacterial profiles among the three groups. The infected group exhibited an increased abundance of bacteria genus Gluconobacter, while Asaia was prevalent in both non-infected and negative control groups. Chryseobacterium was prominent in the negative control group. These findings highlight potential alterations in the distribution and abundance of gut microbiomes in response to CHIKV infection status. This study provides valuable insights into the dynamic relationship between midgut bacteria and CHIKV, underscoring the potential for alterations in bacterial composition depending on infection status. Understanding the relationships between mosquitoes and their microbiota holds promise for developing new methods and tools to enhance existing strategies for disease prevention and control. This research advances our understanding of the circulating bacterial composition, opening possibilities for new approaches in combating mosquito-borne diseases. [ABSTRACT FROM AUTHOR]

The Plasmodium is responsible for malaria which poses a major health threat, globally. This study is based on the estimation of the relative abundance of mosquitoes, and finding out the correlations of meteorological parameters (temperature, humidity and rainfall) with the abundance of mosquitoes. In addition, this study also focused on the use of nested PCR (species-specific nucleotide sequences of 18S rRNA genes) to explore the Plasmodium spp. in female Anopheles. In the current study, the percentage relative abundance of Culex mosquitoes was 57.65% and Anopheles 42.34% among the study areas. In addition, the highest number of mosquitoes was found in March in district Mandi Bahauddin at 21 °C (Tmax = 27, Tmin = 15) average temperature, 69% average relative humidity and 131 mm rainfall, and these climatic factors were found to affect the abundance of the mosquitoes, directly or indirectly. Molecular analysis showed that overall, 41.3% of the female Anopheles pools were positive for genus Plasmodium. Among species, the prevalence of Plasmodium (P.) vivax (78.1%) was significantly higher than P. falciparum (21.9%). This study will be helpful in the estimation of future risk of mosquito-borne diseases along with population dynamic of mosquitoes to enhance the effectiveness of vector surveillance and control programs. [ABSTRACT FROM AUTHOR]

The control of arthropod disease vectors using chemical insecticides is vital in combating malaria, however the increasing insecticide resistance (IR) poses a challenge. Furthermore, climate variability affects mosquito population dynamics and subsequently IR propagation. We present a mathematical model to decipher the relationship between IR in Anopheles gambiae populations and climate variability. By adapting the susceptible-infected-resistant (SIR) framework and integrating temperature and rainfall data, our model examines the connection between mosquito dynamics, IR, and climate. Model validation using field data achieved 92% accuracy, and the sensitivity of model parameters on the transmission potential of IR was elucidated (e.g. μPRCC = 0.85958, p-value < 0.001). In this study, the integration of high-resolution covariates with the SIR model had a significant impact on the spatial and temporal variation of IR among mosquito populations across Africa. Importantly, we demonstrated a clear association between climatic variability and increased IR (width = [0–3.78], α = 0.05). Regions with high IR variability, such as western Africa, also had high malaria incidences thereby corroborating the World Health Organization Malaria Report 2021. More importantly, this study seeks to bolster global malaria combat strategies by highlighting potential IR 'hotspots' for targeted intervention by National malria control programmes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Mosquitoes (Culicidae) represent the main vector insects globally, and they also inhabit many of the terrestrial and aquatic habitats of the world. DNA barcoding and metabarcoding are now widely used in both research and routine practices involving mosquitoes. However, these methodologies rely on information available in databases consisting of barcode sequences representing taxonomically identified voucher specimens. In this study, we assess the availability of public data for mosquitoes in the main online databases, focusing specifically on the two most widely used DNA barcoding markers in Culicidae: COI and ITS2. In addition, we test hypotheses on possible factors affecting species coverage (i.e., the percentage of species covered in the online databases) for COI in different countries and the occurrence of the DNA barcode gap for COI. Our findings showed differences in the data publicly available in the repositories, with a taxonomic or species coverage of 28.4–30.11% for COI in BOLD + GenBank, and 12.32% for ITS2 in GenBank. Afrotropical, Australian and Oriental biogeographic regions had the lowest coverages, while Nearctic, Palearctic and Oceanian had the highest. The Neotropical region had an intermediate coverage. In general, countries with a higher diversity of mosquitoes and higher numbers of medically important species had lower coverage. Moreover, countries with a higher number of endemic species tended to have a higher coverage. Although our DNA barcode gap analyses suggested that the species boundaries need to be revised in half of the mosquito species available in the databases, additional data must be gathered to confirm these results and to allow explaining the occurrence of the DNA barcode gap. We hope this study can help guide regional species inventories of mosquitoes and the completion of a publicly available reference library of DNA barcodes for all mosquito species. [ABSTRACT FROM AUTHOR]

Developing a safe and potent repellent of mosquitoes applicable to human skins is an effective measure against the spread of mosquito-borne diseases. Recently, we have identified that hydrophobic solutions such as low viscosity polydimethylsiloxane (L-PDMS) spread on a human skin prevent mosquitoes from staying on and biting it. This is likely due to the ability of L-PDMS in wetting mosquito legs and exerting a capillary force from which the mosquitoes attempt to escape. Here we show three additional functions of L-PDMS that can contribute to repel Aedes albopictus, by combining physicochemical analysis and behavioral assays in both an arm cage and a virtual flight arena. First, L-PDMS, when mixed with topical repellents and applied on a human skin, enhances the effect of topical repellents in reducing mosquito bites by efficiently transferring them to mosquito legs upon contact. Second, L-PDMS applied to mosquito tarsi compromises visual object tracking during flight, exerting an influence outlasting the contact. Finally, L-PDMS applied to mosquito tarsi acts as an aversive reinforcer in associative learning, making mosquitoes avoid the conditioned odor. These results uncover a multifaceted potential of L-PDMS in altering a sequence of mosquito behaviors from biting a human skin, visual object tracking following takeoff, to the response to an odor linked with L-PDMS. [ABSTRACT FROM AUTHOR]

Great advances in automated identification systems, or 'smart traps', that differentiate insect species have been made in recent years, yet demonstrations of field-ready devices under free-flight conditions remain rare. Here, we describe the results of mixed-species identification of female mosquitoes using an advanced optoacoustic smart trap design under free-flying conditions. Point-of-capture classification was assessed using mixed populations of congeneric (Aedes albopictus and Aedes aegypti) and non-congeneric (Ae. aegypti and Anopheles stephensi) container-inhabiting species of medical importance. Culex quinquefasciatus, also common in container habitats, was included as a third species in all assessments. At the aggregate level, mixed collections of non-congeneric species (Ae. aegypti, Cx. quinquefasciatus, and An. stephensi) could be classified at accuracies exceeding 90% (% error = 3.7–7.1%). Conversely, error rates increased when analysing individual replicates (mean % error = 48.6; 95% CI 8.1–68.6) representative of daily trap captures and at the aggregate level when Ae. albopictus was released in the presence of Ae. aegypti and Cx. quinquefasciatus (% error = 7.8–31.2%). These findings highlight the many challenges yet to be overcome but also the potential operational utility of optoacoustic surveillance in low diversity settings typical of urban environments. [ABSTRACT FROM AUTHOR]

Mosquitoes are primary vectors of pathogens impacting humans, wildlife, and livestock. Among them, the Asian tiger mosquito, Aedes albopictus, stands out as an invasive species with a global distribution, having established populations on every continent except Antarctica. Recent findings incriminate Ae. albopictus in the local transmission of several pathogens causing human diseases, including dengue, chikungunya, and Zika viruses and worm parasites as Dirofilaria. In Spain, the establishment of Ae. albopictus occurred in 2004 and it rapidly expanded, currently reaching southern provinces and creating novel epidemiological scenarios in recently invaded areas. In this study, we conducted captures of Ae. albopictus from May to November 2022 in two provinces, Granada and Malaga, situated near the current edge of the species' expanding range in Spain. The objective was to identify the primary factors influencing their captures in these regions. Mosquitoes were captured using BG-Sentinel traps baited with CO2 and BG-Lure, and miniature CDC-UV traps in five different localities. Our findings underscore the influence of both extrinsic factors, such as locality, and intrinsic factors, including mosquito sex, on the abundance of captured Ae. albopictus. A higher abundance of Ae. albopictus was observed in the Malaga province compared to localities in the Granada province. Furthermore, similar numbers of Ae. albopictus mosquitoes were captured in more urbanized areas of Granada, while the lowest counts were recorded in the less urbanized area. These results were compared to captures of another common species in the area, specifically Culex pipiens. Overall, these results represent the first monitoring of invasive Ae. albopictus in the area and are discussed in the light of the potential importance of the species as a nuisance for humans and vectors of pathogens of public health relevance. [ABSTRACT FROM AUTHOR]

Mosquito-borne diseases pose ongoing global health concerns, demanding more cost-efficient methods to detect pathogens to support enhanced surveillance efforts. This study introduces an adapted TRIzol-based high-throughput RNA extraction protocol, tailored for the detection of California serogroup viruses in pooled mosquito samples in a rapid and cost-effective manner. This approach provided consistent RNA yields and sensitive viral detection relative to two commercial extraction kits (QIAGEN RNeasy Mini Kit and MACHEREY–NAGEL NucleoSpin RNA Plus Kit). The incorporation of a user-friendly and non-spiking-based RT-qPCR internal control designed for the 18S rRNA gene in mosquitoes minimizes potential false positives/negatives, improving the fidelity of viral detection outcomes. Effective RNA yields, purity, and successful target amplification across 25 mosquito species and varied pool sizes (1–50 mosquitoes per tube) affirm the reliability of our approach. The extraction method is cost-effective, with an incurred cost of $0.58 CAD per sample, in contrast to the $5.25 CAD cost per sample of the two kits, rendering it promising for mosquito-borne disease surveillance initiatives. [ABSTRACT FROM AUTHOR]

The mosquito species Aedes aegypti (L.) is known to act as a vector in the transmission of various diseases, including dengue fever and yellow fever. The use of insect repellents is one of precautionary measures used to mitigate the risk of these diseases in humans by reducing mosquito biting. Nepetalactone, a potent natural insect repellent primarily found in catnip (Nepeta cataria) essential oil, has emerged as a promising candidate for mosquito repellence. Here, we evaluated the potential of catnip essential oil (> 95% nepetalactone) for use as a mosquito repellent. Using a Y-tube olfactometer and human hands as an attractant, we analysed the effectiveness of catnip oil at repelling the mosquito species Aedes aegypti. We tested a range of dilutions of catnip essential oil and found that concentrations as low as 2% were effective at repelling > 70% of mosquitoes for between one and four hours after repellent application. These findings suggest that nepetalactone could potentially be used as a natural, effective alternative to synthetic mosquito repellents, thereby offering protection against vector-borne diseases. [ABSTRACT FROM AUTHOR]

Due to climate change and the expanding geographical ranges of key mosquito species, several mosquito-borne viruses (MBVs) have recently emerged in Europe. Understanding people's perceptions and behaviours towards these viruses and the mosquitoes capable of transmitting them is crucial for implementing effective prevention measures and targeted communication campaigns. However, there is currently no appropriate validated survey for European populations to assess this. This study developed and validated a standardized survey, based on the Health Belief Model (HBM), to assess perceptions of mosquitoes and MBVs among Europe's residents. The survey was distributed online to United Kingdom (UK), Dutch and Spanish participants through panel providers. Survey validity and reliability were tested using confirmatory factor analysis (CFA) and Cronbach's alpha. The optimised survey was completed by 336 UK, 438 Dutch and 475 Spanish residents, respectively, and the HBM items passed our validity and reliability testing in all three countries. The final survey has 57 questions, including 19 validated HBM items, and questions to assess demographic characteristics, knowledge, prevention measures and behavioural determinants. Our MosquitoWise survey bridges researchers' understandings of European residents' perceptions and knowledge as a first step to improve preventive behaviour towards mosquitoes and MBVs and guide prevention and communication initiatives. [ABSTRACT FROM AUTHOR]

The resident human skin microbiome is responsible for the production of most of the human scents that are attractive to mosquitoes. Hence, engineering the human skin microbiome to synthesize less of mosquito attractants or produce repellents could potentially reduce bites and prevent the transmission of deadly mosquito-borne pathogens. In order to further characterize the human skin volatilome, we quantified the major volatiles of 39 strains of skin commensals (Staphylococci and Corynebacterium). Importantly, to validate the behavioral activity of these volatiles, we first assessed landing behavior triggered by human skin volatiles. We demonstrated that landing behavior is gated by the presence of carbon dioxide and L-(+)-lactic acid. This is similar to the combinatorial coding triggering mosquito short range attraction. Repellency behavior to selected skin volatiles and terpenes was tested in the presence of carbon dioxide and L-(+)-lactic acid. In a 2-choice landing behavior context, the skin volatiles 2- and 3-methyl butyric acids reduced mosquito landing by 62.0–81.6% and 87.1–99.6%, respectively. Similarly, the terpene geraniol was capable of reducing mosquito landing behavior by 74.9%. We also tested the potential repellency effects of terpenes in mosquitoes at short-range using a 4-port olfactometer. In these assays, geraniol reduced mosquito attraction (69–78%) to a mixture of key human kairomones carbon dioxide, L-(+)-lactic acid, and ammonia. These findings demonstrate that carbon dioxide and L-(+)-lactic acid change the valence of other skin volatiles towards mosquito landing behavior. Moreover, this study offers candidate odorants to be targeted in a novel strategy to reduce attractants or produce repellents by the human skin microbiota that may curtail mosquito bites, and subsequent mosquito-borne disease. [ABSTRACT FROM AUTHOR]

Sexual dimorphism is almost ubiquitous in animals. A common pattern observed across multiple taxa involves differences in development time (sexual bimaturism) and body size (sexual size dimorphism) between conspecific males and females. Furthermore, a strict association of dimorphism at these traits has been documented in several taxa, where the sex showing shorter development time also has a smaller body size than the other sex. Growth and development are strongly dependent on environmental conditions during individual life-cycle in ectotherms, inducing considerable phenotypic plasticity. However, how phenotypic plasticity affects the association between sexual dimorphism in development time and body size remains unclear. Here, we tracked development time, body size, and body mass throughout the ontogeny of the mosquito Aedes mariae. The larval development of this species is strictly linked to Mediterranean Sea rock-pools, whose highly variable environmental conditions over minimal time frames make this organism-environment system ideal for exploring plasticity-led eco-evolutionary processes. We found differential plasticity between males and females, dissolving the link between dimorphism in development time and body size under increasing temperature and decreasing salinity conditions. These findings contrast with the current hypotheses proposed to explain the origin of the association between sexual bimaturism and sexual size dimorphism, highlighting the condition dependence of sexual dimorphism patterns and the need to consider phenotypic plasticity in future studies on their evolution. [ABSTRACT FROM AUTHOR]

The ability to distinguish between the abdominal conditions of adult female mosquitoes has important utility for the surveillance and control of mosquito-borne diseases. However, doing so requires entomological training and time-consuming manual effort. Here, we design computer vision techniques to determine stages in the gonotrophic cycle of female mosquitoes from images. Our dataset was collected from 139 adult female mosquitoes across three medically important species—Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus—and all four gonotrophic stages of the cycle (unfed, fully fed, semi-gravid, and gravid). From these mosquitoes and stages, a total of 1959 images were captured on a plain background via multiple smartphones. Subsequently, we trained four distinct AI model architectures (ResNet50, MobileNetV2, EfficientNet-B0, and ConvNeXtTiny), validated them using unseen data, and compared their overall classification accuracies. Additionally, we analyzed t-SNE plots to visualize the formation of decision boundaries in a lower-dimensional space. Notably, ResNet50 and EfficientNet-B0 demonstrated outstanding performance with an overall accuracy of 97.44% and 93.59%, respectively. EfficientNet-B0 demonstrated the best overall performance considering computational efficiency, model size, training speed, and t-SNE decision boundaries. We also assessed the explainability of this EfficientNet-B0 model, by implementing Grad-CAMs—a technique that highlights pixels in an image that were prioritized for classification. We observed that the highest weight was for those pixels representing the mosquito abdomen, demonstrating that our AI model has indeed learned correctly. Our work has significant practical impact. First, image datasets for gonotrophic stages of mosquitoes are not yet available. Second, our algorithms can be integrated with existing citizen science platforms that enable the public to record and upload biological observations. With such integration, our algorithms will enable the public to contribute to mosquito surveillance and gonotrophic stage identification. Finally, we are aware of work today that uses computer vision techniques for automated mosquito species identification, and our algorithms in this paper can augment these efforts by enabling the automated detection of gonotrophic stages of mosquitoes as well. [ABSTRACT FROM AUTHOR]

Barrier bednets (BBnets), regular bednets with a vertical insecticidal panel to target mosquitoes above the bednet roof, where they are most active, have the potential to improve existing Insecticidal Treated Bednets (ITNs), by reducing the quantity of insecticide required per net, reducing the toxic risks to those using the net, potentially increasing insecticide choice. We evaluated the performance of PermaNet 3.0 (P3) and untreated (Ut) bed nets with and without pyrethroid and piperonyl butoxide roof barriers in killing pyrethroid-resistant and susceptible Anopheles gambiae, simultaneously video-recording mosquito flight tracks. Bioassay results showed that treated roof barriers, particularly the longitudinal P3 barrier (P3L) could be an effective addition to a bed net: P3 + P3L were consistently significantly more effective than the reference P3 bednet while performance of untreated nets could be raised to equal that of the reference P3 following the addition of a P3 barrier. The BBnet's potential to augment existing bednets and enhance their performance is considered. [ABSTRACT FROM AUTHOR]

While residual insecticide applications have the potential to decrease pathogen transmission by reducing the density of vectors and shifting the age structure of the adult mosquito population towards younger stages of development, this double entomological impact has not been documented for Aedes aegypti. Aedes collected from households enrolled in a cluster-randomized trial evaluating the epidemiological impact of targeted indoor residual spraying (TIRS) in Merida, Mexico, were dissected and their age structure characterized by the Polovodova combined with Christopher's ovariole growth methods. In total, 813 females were dissected to characterize age structure at 1, 3, 6, and 9 months post-TIRS. Significant differences in the proportion of nulliparous Ae. aegypti females between the treatment groups was found at one-month post-TIRS (control: 35% vs. intervention: 59%), three months (20% vs. 49%) but not at six or nine months post-TIRS. TIRS significantly shiftted Ae. aegypti age structure towards younger stages and led to a non-linear reduction in survivorship compared to the control arm. Reduced survivorship also reduced the number of arbovirus transmitting females (those who survived the extrinsic incubation period). Our findings provide strong evidence of the full entomological impact of TIRS, with important implications for quantifying the epidemiological impact of vector control methods. [ABSTRACT FROM AUTHOR]

Although larval diet quality may affect adult mosquito fitness, its impact on parasite development is scarce. Plant pollen from Zea mays, Typha latifolia, and Prosopis juliflora was ultraviolet-sterilized and examined for effects on larval development, pupation rate, adult mosquito longevity, survival and infectivity. The control larvae were fed Tetramin fish food as a comparator food. Four treatment and two control groups were used for each pollen diet, and each experimental tray had 25 larvae. Female An. arabiensis were starved overnight and exposed to infectious blood using a membrane-feeding system. The Kaplan–Meier curves and log-rank test were used for analysis. The Z. mays pollen diet increased malaria mosquito survival and pupation rate (91.3%) and adult emergence (85%). Zea mays and Tetramin fish food had comparable adulthood development times. Adults who emerged from larvae fed Z. mays pollen had the longest average wing length (3.72 mm) and were more permissive to P. vivax (45%) and P. falciparum (27.5%). They also survived longer after feeding on infectious blood and had the highest number of P. vivax oocysts. Zea mays pollen improved larval development, adult mosquito longevity, survival and infectivity to Plasmodium. Our findings suggest that malaria transmission in Z. mays growing villages should be monitored. [ABSTRACT FROM AUTHOR]

Molecular tools for modulating transgene expression in Aedes aegypti are few. Here we demonstrate that adjustments to the AePUb promoter length can alter expression levels of two reporter proteins in Ae. aegypti cell culture and in mosquitoes. This provides a simple means for increasing or decreasing expression of a gene of interest and easy translation from cells to whole insects. [ABSTRACT FROM AUTHOR]

Mosquitoes interact with various organisms in the environment, and female mosquitoes in particular serve as vectors that directly transmit a number of microorganisms to humans and animals by blood-sucking. Comprehensive analysis of mosquito-borne viruses has led to the understanding of the existence of diverse viral species and to the identification of zoonotic arboviruses responsible for significant outbreaks and epidemics. In the present study on mosquito-borne bunyaviruses we employed a broad-spectrum RT-PCR approach and identified eighteen different additional species in the Phenuiviridae family and also a number of related but unclassified bunyaviruses in mosquitoes collected in Zambia. The entire RNA genome segments of the newly identified viruses were further analyzed by RNA sequencing with a ribonuclease R (RNase R) treatment to reduce host-derived RNAs and enrich viral RNAs, taking advantage of the dsRNA panhandle structure of the bunyavirus genome. All three or four genome segments were identified in eight bunyavirus species. Furthermore, L segments of three different novel viruses related to the Leishbunyaviridae were found in mosquitoes together with genes from the suspected host, the Crithidia parasite. In summary, our virus detection approach using a combination of broad-spectrum RT-PCR and RNA sequencing analysis with a simple virus enrichment method allowed the discovery of novel bunyaviruses. The diversity of bunyaviruses is still expanding and studies on this will allow a better understanding of the ecology of hematophagous mosquitoes. [ABSTRACT FROM AUTHOR]

From October 2014 to February 2019, local authorities in Townsville, North Queensland, Australia continually introduced Wolbachia-infected mosquitoes to control seasonal outbreaks of dengue infection. In this study, we develop a mathematical modelling framework to estimate the effectiveness of this intervention as well as the relative dengue transmission rates of Wolbachia-infected and wild-type mosquitoes. We find that the transmission rate of Wolbachia-infected mosquitoes is reduced approximately by a factor of 20 relative to the uninfected wild-type population. In addition, the Townsville Wolbachia release program led to a 65% reduction in predicted dengue incidence during the release period and over 95% reduction in the 24 months that followed. Finally, to investigate the potential impact of other Wolbachia release programs, we use our estimates of relative transmissibility to calculate the relationship between the reproductive number of dengue and the proportion of Wolbachia-infected mosquitoes in the vector population. [ABSTRACT FROM AUTHOR]

Significant pathogens that have resurfaced in humans originate from transmission from animal to human populations. In the Americas, yellow fever cases in humans are usually associated with spillover from non-human primates via mosquitoes. The present study characterized the prevalence of the yellow fever vector Haemagogus leucocelaenus in Rio de Janeiro, Brazil. The Atlantic Forest fragment chosen is an area of translocation of the golden lion tamarin (Leontopithecus rosalia), where 10 ovitraps were installed to collect mosquito eggs in Fazenda Três Irmãos, at Silva Jardim city, from March 2020 to October 2022. A total of 1514 eggs were collected, of which 1153 were viable; 50% belonged to medically important mosquito species and 24% to the yellow fever vector species, Hg. leucocelaenus. The months of December 2020 (n = 252), November 2021 (n = 188), and January 2022 (n = 252) had the highest densities of this vector. Haemagogus leucocelaenus was positively correlated with temperature (r = 0.303) and humidity (r = 0.48), with eggs hatching up to the 15th immersion with higher abundance of females. Implementing mosquito monitoring for arbovirus activity can help protect both the golden lion tamarin and human populations from the threat of arbovirus transmission. [ABSTRACT FROM AUTHOR]

Mosquitoes present a global health challenge due to their ability to transmit human and animal pathogens upon biting and blood feeding. The investigation of tastants detected by mosquitoes and their associated feeding behaviors is needed to answer physiological and ecological questions that could lead to novel control methods. A high-throughput system originally developed for research in fruit flies feeding behavior, the flyPAD, was adapted and tested for behaviors associated with the interaction or consumption of liquid diets offered to females of the mosquito Aedes aegypti Liverpool strain. Females were given water, sucrose solution and sheep blood in choice and non-choice assays. The volume ingested was evaluated with fluorescein. The placement of the system on a heated surface allowed blood consumption, and without females puncturing a membrane. The flyPAD system recorded nine feeding behavioral variables, of which the number of sips and number of activity bouts correlated with meal volume ingested for both sucrose solution and blood. The adaptation to mosquitoes of the flyPAD system differentiated feeding behavior variables between two feeding deterrents, capsaicin, and caffeine. The flyPAD has potential to quickly assess diverse tastants in both sucrose and blood and may contribute to characterizing more precisely their mode of action. [ABSTRACT FROM AUTHOR]

Mosquito control in Egypt depends on applying chemical synthetic pesticides that impact negatively on human health and the environment as well as the development of antibiotic and chemical resistance. This study aims to control the 3rd and 4th instars of Culex pipiens larvae using four bacterial strains. According to Phenotypic and molecular identification, the four isolates were identified as Bacillus subtilis MICUL D2023, Serratia marcescens MICUL A2023, Streptomyces albus LARVICID, and Pseudomonas fluorescens MICUL B2023. All strains were deposited in GenBank under accession numbers OQ764791, OQ729954, OQ726575, and OQ891356, respectively. Larvicidal activity of all microbial strain metabolites against a field strain of C. pipiens explored low LC50 results and reached its lowest values on the 3rd day with values of 6.40%, 38.4%, and 46.33% for P. fluorescens, S. albus, and S. marcescens, respectively. In addition, metabolites of P. fluorescence were more toxic than those of S. albus, followed by S. marcescens. B. subtilis shows no larvicidal effect on both field and lab mosquito strains. Microscopic alterations of 3rd and 4th instars showed toxic effects on different body parts (thorax, midgut, and anal gills), including losing external hairs, abdominal breakage, and larvae shrinkage, as well as different histological malformations in the digestive tract, midgut, and cortex. GC–MS analysis detected 51, 30, and 32 different active compounds from S. albus, S. marcescens, and P. fluorescens, respectively. GC detected 1, 2-BENZEA2:A52NEDICARBOXYLIC ACID, 2-Cyclohexene-1-carboxylic-acid-5-2-butenyl-methyl ester, and 3 octadecahydro2R3S4Z9Z-11R-12S from S. albus, S. marcesens, and P. fluorescens, respectively. Total protein, Total carbohydrate, and Acetylcholine esterase activity indicated significantly low levels on the 3rd day. All strain metabolites were safe against HSF cell lines. The docking results confirmed the role of the produced metabolites as larvicidal agents and Acetylcholine esterase inhibition. Such a problem need more studies on applying more and more natural pesticides. [ABSTRACT FROM AUTHOR]

Chlorfenapyr is a pro-insecticide increasingly used in combination with pyrethroids such as a-cypermethrin or deltamethrin in insecticide treated bednets (ITNs) to control malaria transmitted by pyrethroid-resistant mosquito populations. Chlorfenapyr requires P450 activation to produce tralopyril and other bioactive metabolites. Pyrethroid resistance is often associated with elevated levels of chemoprotective P450s with broad substrate specificity, which could influence chlorfenapyr activity. Here, we have investigated chlorfenapyr metabolism by a panel of eight P450s commonly associated with pyrethroid resistance in An. gambiae and Ae. aegypti, the major vectors of malaria and arboviruses. Chlorfenapyr was activated to tralopyril by An. gambiae CYP6P3, CYP9J5, CYP9K1 and Ae. aegypti, CYP9J32. The Kcat/KM value of 0.66 μM−1 min−1 for CYP9K1 was, 6.7 fold higher than CYP6P3 and CYP9J32 (both 0.1 μM−1 min−1) and 22-fold higher than CYP9J5 (0.03 μM−1 min−1). Further investigation of the effect of -cypermethrin equivalent to the ratios used with chlorfenapyr in bed nets (~ 1:2 molar ratio) resulted in a reduction in chlorfenapyr metabolism by CYP6P3 and CYP6K1 of 76.8% and 56.8% respectively. This research provides valuable insights into the metabolism of chlorfenapyr by mosquito P450s and highlights the need for continued investigation into effective vector control strategies. [ABSTRACT FROM AUTHOR]

Early detection of pathogens in vectors is important in preventing the spread of arboviral diseases, providing a timely indicator of pathogen circulation before outbreaks occur. However, entomological surveillance may face logistical constraints, such as maintaining the cold chain, and resource limitations, such as the field and laboratory workload of mosquito processing. We propose an FTA card-based trapping system that aims to simplify both field and laboratory phases of arbovirus surveillance. We modified a BG-Sentinel trap to include a mosquito collection chamber and a sugar feeding source through an FTA card soaked in a long-lasting viscous solution of honey and hydroxy-cellulose hydrogel. The FTA card ensures environmental preservation of nucleic acids, allowing continuous collection and feeding activity of specimens for several days and reducing the effort required for viral detection. We tested the trap prototype during two field seasons (2019 and 2021) in North-eastern Italy and compared it to CDC-CO2 trapping applied in West Nile and Usutu virus regional surveillance. Collections by the BG-FTA approach detected high species diversity, including Culex pipiens, Aedes albopictus, Culex modestus, Anopheles maculipennis sensu lato and Ochlerotatus caspius. When used for two-days sampling, the BG-FTA trap performed equally to CDC also for the WNV-major vector Cx. pipiens. The FTA cards detected both WNV and USUV, confirming the reliability of this novel approach to detect viral circulation in infectious mosquitoes. We recommend this surveillance approach as a particularly useful alternative in multi-target surveillance, for sampling in remote areas and in contexts characterized by high mosquito densities and diversity. [ABSTRACT FROM AUTHOR]

Microorganisms present in mosquitoes and their interactions are key factors affecting insect development. Among them, Wolbachia is closely associated with the host and affects several fitness parameters. In this study, the bacterial and fungal microbiota from two laboratory Culex quinquefasciatus isolines (wild type and tetracycline-cured) were characterized by metagenome amplicon sequencing of the ITS2 and 16S rRNA genes at different developmental stages and feeding conditions. We identified 572 bacterial and 61 fungal OTUs. Both isolines presented variable bacterial communities and different trends in the distribution of diversity among the groups. The lowest bacterial richness was detected in sugar-fed adults of the cured isoline, whereas fungal richness was highly reduced in blood-fed mosquitoes. Beta diversity analysis indicated that isolines are an important factor in the differentiation of mosquito bacterial communities. Considering composition, Penicillium was the dominant fungal genus, whereas Wolbachia dominance was inversely related to that of Enterobacteria (mainly Thorsellia and Serratia). This study provides a more complete overview of the mosquito microbiome, emphasizing specific highly abundant components that should be considered in microorganism manipulation approaches to control vector-borne diseases. [ABSTRACT FROM AUTHOR]

Mosquito-borne diseases' impact on human health is among the most prominent of all communicable diseases. With limited pool of tools to contrast these diseases, public health focus remains preventing mosquito-human contacts. Applying a hierarchical spatio-temporal Bayesian model on West Nile virus (WNV) surveillance data from Greece, we aimed to investigate the impact of climatic and environmental factors on Culex mosquitoes' population. Our spatio-temporal analysis confirmed climatic factors as major drivers of WNV-transmitting-Culex mosquitoes population dynamics, with temperature and long periods of moderate-to-warm climate having the strongest positive effect on mosquito abundance. Conversely, rainfall, high humidity, and wind showed a negative impact. The results suggest the presence of statistically significant differences in the effect of regional and seasonal characteristics, highlighting the complex interplay between climatic, geographical and environmental factors in the dynamics of mosquito populations. This study may represent a relevant tool to inform public health policymakers in planning preventive measures. [ABSTRACT FROM AUTHOR]

Zika virus (ZIKV), a mosquito-borne flavivirus, has been continually emerging and re-emerging since 2010, with sporadic cases reported annually in Thailand, peaking at over 1000 confirmed positive cases in 2016. Leveraging high-throughput sequencing technologies, specifically whole genome sequencing (WGS), has facilitated rapid pathogen genome sequencing. In this study, we used multiplex amplicon sequencing on the Illumina Miseq instrument to describe ZIKV WGS. Six ZIKV WGS were derived from three samples of field-caught Culex quinquefasciatus mosquitoes (two males and one female) and three urine samples collected from patients in three different provinces of Thailand. Additionally, successful isolation of a ZIKV isolate occurred from a female Cx. quinquefasciatus. The WGS analysis revealed a correlation between the 2020 outbreak and the acquisition of five amino acid changes in the Asian lineage ZIKV strains from Thailand (2006), Cambodia (2010 and 2019), and the Philippines (2012). These changes, including C-T106A, prM-V1A, E-V473M, NS1-A188V, and NS5-M872V, were identified in all seven WGS, previously linked to significantly higher mortality rates. Furthermore, phylogenetic analysis indicated that the seven ZIKV sequences belonged to the Asian lineage. Notably, the genomic region of the E gene showed the highest nucleotide diversity (0.7–1.3%). This data holds significance in informing the development of molecular tools that enhance our understanding of virus patterns and evolution. Moreover, it may identify targets for improved methods to prevent and control future ZIKV outbreaks. [ABSTRACT FROM AUTHOR]

The need for evidence-based data, to inform policy decisions on malaria vector control interventions in Nigeria, necessitated the establishment of mosquito surveillance sites in a few States in Nigeria. In order to make evidence-based-decisions, predictive studies using available data becomes imperative. We therefore predict the distribution of the major members of the Anopheles gambiae s.l. in Nigeria. Immature stages of Anopheles were collected from 72 study locations which span throughout the year 2020 resulted in the identification of over 60,000 Anopheline mosquitoes. Of these, 716 breeding sites were identified with the presence of one or more vector species from the An. gambiae complex and were subsequently used for modelling the potential geographical distribution of these important malaria vectors. Maximum Entropy (MaxEnt) distribution modeling was used to predict their potentially suitable vector habitats across Nigeria. A total of 23 environmental variables (19 bioclimatic and four topographic) were used in the model resulting in maps of the potential geographical distribution of three dominant vector species under current climatic conditions. Members of the An. gambiae complex dominated the collections (98%) with Anopheles stephensi, Anopheles coustani, Anopheles funestus, Anopheles moucheti, Anopheles nilli also present. An almost equal distribution of the two efficient vectors of malaria, An. gambiae and Anopheles coluzzii, were observed across the 12 states included in the survey. Anopheles gambiae and Anopheles coluzzii had almost equal, well distributed habitat suitability patterns with the latter having a slight range expansion. However, the central part of Nigeria (Abuja) and some highly elevated areas (Jos) in the savannah appear not suitable for the proliferation of these species. The most suitable habitat for Anopheles arabiensis was mainly in the South-west and North-east. The results of this study provide a baseline allowing decision makers to monitor the distribution of these species and establish a management plan for future national mosquito surveillance and control programs in Nigeria. [ABSTRACT FROM AUTHOR]

Selection of mosquito collection methods is of crucial importance to evaluate the impact of vector control tools on entomological outcomes. During a cluster randomised control trial evaluating the relative efficacy of two dual-active ingredient (a.i.) long-lasting insecticidal nets (LLINs) compared to pyrethroid-only LLINs, we assessed the performance of different mosquito collection methods: Human landing catches (HLC), Centers for Disease Control and Prevention (CDC) light traps, and pyrethrum spray catches (PSC). Anopheles mosquitoes were collected using three collection methods in 4 houses, in each of the 60 trial clusters at baseline and every quarter for 24 months using PSCs and HLCs, while CDC light traps were performed during two quarters only. Mean density of vectors collected per method per night was the highest with HLCs (15.9), followed by CDC light traps (6.8); with PSCs (1.1) collecting 10 times less mosquitoes than HLCs. All three collection methods collected fewer mosquitoes in the Interceptor G2® dual a.i. arm, compared to the other trial arms, although only HLCs and PSCs demonstrated strong evidence of this due to a greater number of collection rounds undertaken, than CDC light traps. The broadly similar results regarding the differential impact of the two dual a.i. LLINs showed by the three collection methods suggest that the more ethically acceptable, cheaper, and logistically simpler methods such as CDC light traps could be prioritised for use in large community trials for measuring the efficacy of vector control tools. [ABSTRACT FROM AUTHOR]

Pyrethroid-chlorfenapyr nets have demonstrated improved entomological and epidemiological impact in trials across Africa. This is driving increased demand for this novel net class in malaria-endemic countries. PermaNet Dual is a new deltamethrin-chlorfenapyr net developed by Vestergaard Sàrl to provide more options to malaria control programmes. We performed an experimental hut trial to evaluate the efficacy of PermaNet Dual against wild, free-flying pyrethroid-resistant Anopheles gambiae sensu lato in Covè, Benin. PermaNet Dual induced superior levels of mosquito mortality compared to a pyrethroid-only net and a pyrethroid-piperonyl butoxide net both when unwashed (77% with PermaNet Dual vs. 23% with PermaNet 2.0 and 56% with PermaNet 3.0, p < 0.001) and after 20 standardised washes (75% with PermaNet Dual vs. 14% with PermaNet 2.0 and 30% with PermaNet 3.0, p < 0.001). Using a provisional non-inferiority margin defined by the World Health Organisation, PermaNet Dual was also non-inferior to a pyrethroid-chlorfenapyr net that has demonstrated improved public health value (Interceptor G2), for vector mortality (79% vs. 76%, OR = 0.878, 95% CIs 0.719–1.073) but not for blood-feeding protection (35% vs. 26%, OR = 1.424, 95% CIs 1.177–1.723). PermaNet Dual presents an additional option of this highly effective net class for improved control of malaria transmitted by pyrethroid-resistant mosquitoes. [ABSTRACT FROM AUTHOR]

The control of malaria parasite transmission from mosquitoes to humans is hampered by decreasing efficacies of insecticides, development of drug resistance against the last-resort antimalarials, and the absence of effective vaccines. Herein, the anti-plasmodial transmission blocking activity of a recombinant Aspergillus oryzae (A. oryzae-R) fungus strain, which is used in human food industry, was investigated in laboratory-reared Anopheles stephensi mosquitoes. The recombinant fungus strain was genetically modified to secrete two anti-plasmodial effector peptides, MP2 (midgut peptide 2) and EPIP (enolase-plasminogen interaction peptide) peptides. The transstadial transmission of the fungus from larvae to adult mosquitoes was confirmed following inoculation of A. oryzae-R in the water trays used for larval rearing. Secretion of the anti-plasmodial effector peptides inside the mosquito midguts inhibited oocyst formation of P. berghei parasites. These results indicate that A. oryzae can be used as a paratransgenesis model carrying effector proteins to inhibit malaria parasite development in An. stephensi. Further studies are needed to determine if this recombinant fungus can be adapted under natural conditions, with a minimal or no impact on the environment, to target mosquito-borne infectious disease agents inside their vectors. [ABSTRACT FROM AUTHOR]

The current study regarding the effects of larval diets on the life table parameters of dengue mosquitoes, Aedes aegypti was conducted under laboratory conditions at 27 ± 2 °C and 60 ± 5% relative humidity at NIFA (Nuclear Institute for Food and Agriculture) Peshawar, Pakistan. The data on life table parameters of Ae. aegypti reared on Diet 1 (replacement diet), Diet 2 (Khan's diet for Anopheles), Diet 3 (Khan's modified diet) and Diet 4 (IAEA diet) were analyzed using the age-stage, two-sex life table software. Diet 4 (IAEA) was used as a control for comparison. The results indicated that significantly maximum percentage of egg hatching of Ae. aegypti was observed when reared on Diet 4 (73.86%) and Diet 3 (72.90%), while less % of egg hatching was recorded in Diet 1 (40.67%) and Diet 2 (55.53%). The data further showed that the Diet 3 had a highest intrinsic rate of increase (r) (0.097 ± 5.68 day−1), finite rate of increase (λ) (1.10 ± 6.26 day−1) and net reproductive rate (R0) (11.99 ± 1.52 eggs/female) followed by Diet 2 and Diet 4. The mean generation time (T) of Ae. aegypti reared on Diet 3 (23.67 ± 0.86 days) and Diet 1 (24.05 ± 0.61 days) was significantly shorter than Diet 2 (26.15 ± 0.71 days) and Diet 4 (26.41 ± 0.38 days). The overall results revealed that Diet 3 showed good results at different life table parameters of Ae. aegypti and can be used as the preferred diet in the Sterile Insect Technique (SIT) where the mass culture of mosquitoes is required. [ABSTRACT FROM AUTHOR]

The blood feeding performance of female mosquitoes directly impacts their ability to transmit malaria. Yet their host seeking and blood feeding behaviours in the presence of insecticide-treated nets (ITNs) are still poorly understood. This work explores how both insecticide resistant and susceptible Anopheles gambiae s.l. mosquitoes interact with pyrethroid nets (PermaNet 2.0 or Olyset net) or an untreated net (UTN) while attempting to blood feed on a human arm. Regardless of mosquito resistance status, the ITNs did not efficiently prevent host searching but reduced blood feeding success by 34.1 (29.31–38.95) %. The Permanet and Olyset net reduced to 227.5 (208.19–246.77) sec and 235.9 (214.03–257.74) sec the average blood feeding duration from 369.9 (342.78–397.04) sec with the UTN. The ingested blood volume was on average 22% lower for all mosquitoes exposed to insecticide. When feeding through ITNs, the blood volume flow rate of the susceptible strain increased by 35%, but no significant difference was found in the resistant strain. Thus, whilst the presence of the insecticide in ITNs reduced mosquito blood feeding success and blood volume, the mosquito's ability to respond by accelerating her rate of blood ingestion may further reduce the impact of ITNs on resistant mosquitoes. [ABSTRACT FROM AUTHOR]

Microbiota in the mosquito plays an important role in their behavior and vector competence. The composition of their microbiome is strongly influenced by the environment, especially their habitat. The microbiome profiles of adult female Anopheles sinensis mosquitoes from malaria hyperendemic and hypoendemic areas in Republic of Korea were compared using 16S rRNA Illumina sequencing. In different epidemiology groups, the alpha and beta diversity analyses were significant. The major bacterial phylum was Proteobacteria. The most abundant species in the microbiome of hyperendemic mosquitoes were the genera Staphylococcus, Erwinia, Serratia, and Pantoea. Notably, a distinct microbiome profile characterized by the dominance of Pseudomonas synxantha was identified in the hypoendemic area, suggesting a potential correlation between the microbiome profiles and the incidence of malaria cases. [ABSTRACT FROM AUTHOR]

Nanotechnology is a relatively revolutionary area that generates day-to-day advancement. It makes a significant impact on our daily life. For example, in parasitology, catalysis and cosmetics, nanoparticles possess distinctive possessions that make it possible for them in a broad range of areas. We utilized Mollugo oppositifolia L. aqueous leaf extract assisted chemical reduction method to synthesize Co3O4 nanoparticles. Biosynthesized Co3O4 Nps were confirmed via UV–Vis spectroscopy, scanning electron microscope, X-ray diffraction, EDX, Fourier-transform infrared, and HR-TEM analysis. The crystallite size from XRD studies revealed around 22.7 nm. The biosynthesized Co3O4 nanoparticle was further assessed for mosquito larvicidal activity against south-urban mosquito larvae Culex quinquefasciatus, and antimicrobial activities. The synthesized Co3O4 particle (2) displayed significant larvicidal activity towards mosquito larvae Culex quinquefasciatus with the LD50 value of 34.96 µg/mL than aqueous plant extract (1) and control Permethrin with the LD50 value of 82.41 and 72.44 µg/mL. When compared to the standard antibacterial treatment, Ciprofloxacin, the Co3O4 nanoparticle (2) produced demonstrates significantly enhanced antibacterial action against the pathogens E. coli and B. cereus. The MIC for Co3O4 nanoparticles 2 against C. albicans was under 1 μg/mL, which was much lower than the MIC for the control drug, clotrimale, which was 2 µg per milliliter. Co3O4 nanoparticles 2, with a MIC of 2 μg/mL, has much higher antifungal activity than clotrimale, whose MIC is 4 μg/mL, against M. audouinii. [ABSTRACT FROM AUTHOR]

To date, four species of simian malaria parasites including Plasmodium knowlesi, P. cynomolgi, P. inui and P. fieldi have been incriminated in human infections in Thailand. Although the prevalence of malaria in macaque natural hosts has been investigated, their vectors remain unknown in this country. Herein, we performed a survey of Anopheles mosquitoes during rainy and dry seasons in Narathiwat Province, Southern Thailand. Altogether 367 Anopheles mosquitoes were captured for 40 nights during 18:00 to 06:00 h by using human-landing catches. Based on morphological and molecular identification, species composition comprised An. maculatus (37.06%), An. barbirostris s.l. (31.34%), An. latens (17.71%), An. introlatus (10.08%) and others (3.81%) including An. umbrosus s.l., An. minimus, An. hyrcanus s.l., An. aconitus, An. macarthuri and An.kochi. Analyses of individual mosquitoes by PCR, sequencing and phylogenetic inference of the mitochondrial cytochrome genes of both malaria parasites and mosquitoes have revealed that the salivary gland samples of An. latens harbored P. knowlesi (n = 1), P. inui (n = 2), P. fieldi (n = 1), P. coatneyi (n = 1), P. hylobati (n = 1) and an unnamed Plasmodium species known to infect both long-tailed and pig-tailed macaques (n = 2). The salivary glands of An. introlatus possessed P. cynomolgi (n = 1), P. inui (n = 1), P. hylobati (n = 1) and coexistence of P. knowlesi and P. inui (n = 1). An avian malaria parasite P. juxtanucleare has been identified in the salivary gland sample of An. latens. Three other distinct lineages of Plasmodium with phylogenetic affinity to avian malaria species were detected in An. latens, An. introlatus and An. macarthuri. Interestingly, the salivary gland sample of An. maculatus contained P. caprae, an ungulate malaria parasite known to infect domestic goats. Most infected mosquitoes harbored multiclonal Plasmodium infections. All Plasmodium-infected mosquitoes were captured during the first quarter of the night and predominantly occurred during rainy season. Since simian malaria in humans has a wide geographic distribution in Thailand, further studies in other endemic areas of the country are mandatory for understanding transmission and prevention of zoonotic malaria. [ABSTRACT FROM AUTHOR]

Vector-borne, filarial nematode diseases cause significant disease burdens in humans and domestic animals worldwide. Although there is strong direct evidence of parasite-driven immunomodulation of mammalian host responses, there is less evidence of parasite immunomodulation of the vector host. We have previously reported that all life stages of Brugia malayi, a filarial nematode and causative agent of Lymphatic filariasis, secrete extracellular vesicles (EVs). Here we investigate the immunomodulatory effects of microfilariae-derived EVs on the vector host Aedes aegypti. RNA-seq analysis of an Ae. aegypti cell line treated with B. malayi microfilariae EVs showed differential expression of both mRNAs and miRNAs. AAEL002590, an Ae. aegypti gene encoding a serine protease, was shown to be downregulated when cells were treated with biologically relevant EV concentrations in vitro. Injection of adult female mosquitoes with biologically relevant concentrations of EVs validated these results in vivo, recapitulating the downregulation of AAEL002590 transcript. This gene was predicted to be involved in the mosquito phenoloxidase (PO) cascade leading to the canonical melanization response and correspondingly, both suppression of this gene using RNAi and parasite EV treatment reduced PO activity in vivo. Our data indicate that parasite-derived EVs interfere with critical immune responses in the vector host, including melanization. [ABSTRACT FROM AUTHOR]

Mosquito copulation is a crucial determinant of its capacity to transmit malaria-causing Plasmodium parasites as well as underpinning several highly-anticipated vector control methodologies such as gene drive and sterile insect technique. For the anopheline mosquitoes responsible for African malaria transmission, mating takes place within crepuscular male swarms which females enter solely to mate. However, the mechanisms that regulate swarm structure or that govern mate choice remain opaque. We used 3D-video tracking approaches and computer vision algorithms developed for the study of other complex biological systems to document swarming behavior of a lab-adapted Anopheles gambiae line in a lab-based setting. By reconstructing trajectories of individual mosquitoes lasting up to 15.88 s, in swarms containing upwards of 200 participants, we documented swarm-like behavior in both males and females. In single sex swarms, encounters between individuals were fleeting (< 0.75 s). By contrast, in mixed swarms, we were able to detect 79 'brief encounters' (> 0.75 s; < 2.5 s) and 17 longer-lived encounters (> 2.5 s). We also documented several examples of apparent male-male mating competition. These findings represent the first steps towards a more detailed and quantitative description of swarming and courtship behavior in one of the most important vectors of malaria. [ABSTRACT FROM AUTHOR]