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Attraction and mating between male and female animals depend on effective communication between conspecifics. However, in mosquitoes, we have only a rudimentary understanding of the sensory cues and receptors critical for the communication that is essential for reproductive behavior. While it is known that male Aedes aegypti use sound to help them identify females, it is not unclear whether sound detection is absolutely required since other cues such as vision may also participate in mating behavior. To determine the effect of eliminating hearing on mating success, we knocked out the Ae. aegypti TRPVa channel, which is a protein expressed in chordotonal neurons in the Johnstons organ (JO) that respond to sound-induced movements in the antenna. Loss of trpVa eradicated sound-induced responses from the JO, thereby abolishing hearing. Strikingly, mutation of trpVa eliminated mating behavior in males. In contrast, trpVa-null females mated, although this behavior was slightly delayed relative to wild-type females. Males and females produce sounds as they beat their wings at distinct frequencies during flight. Sound mimicking the female wingbeat induced flight, attraction, and copulatory-like behavior in wild-type males without females present, but not in trpVa-null males. Males are known to modulate their wingbeat frequencies before mating in the air, which is a phenomenon referred to as rapid frequency modulation (RFM). We found that RFM was absent in mosquitoes lacking TRPVa. We conclude that the requirement for trpVa and hearing for male reproductive behavior in Aedes is absolute, as mating in the deaf males is eliminated.

The global distribution of Aedes aegypti mosquitoes, particularly in tropical regions, poses a significant public health risk due to their apparent ability to transmit arboviruses such as West Nile virus (WNV). This study aimed to evaluate the vector competence of Ae. aegypti from São Tomé and Príncipe (STP) for the transmission of the WNV PT6.39 strain, considering its potential role as a bridge vector in a region where Culex quinquefasciatus would be the main vector. Aedes aegypti mosquitoes were collected, reared, and experimentally infected with WNV, with viral dissemination and transmission potential assessed 7, 14, and 21 days post infection (dpi). The results showed an increasing trend in infection rates, from 5% at 7 dpi to 35% at 21 dpi, with corresponding dissemination rates of 0%, 100%, and 43%. The transmission rates also increased from 0% at 7 dpi to 67% at 21 dpi, with a maximum transmission efficiency of 10% observed at the final time point. Although Ae. aegypti from STP demonstrated the potential to transmit WNV, the overall transmission efficiency remained relatively low. These findings provide necessary insights into the vector competence of Ae. aegypti in this region, highlighting the importance of continued monitoring and targeted vector control measures to mitigate the risk of potential WNV outbreaks.

This study examines the phenotypic differences between wild-derived F2 Central Valley mosquitoes and the insecticide-susceptible Rockefeller (Rock) lab strain of Ae. aegypti. Given the rarity of wild pyrethroid-susceptible populations, the focus of this work is to develop an understanding of the resistance physiology in this invasive mosquito population and explore the potential of metabolites as diagnostic biomarkers for metabolic resistance. This study utilizes metabolomic, gene expression, and lifespan data for a comparison between strains. The findings indicate that wild-derived mosquitoes with greater metabolic resistance have a lifespan sensitivity to restricted larval nutrition. In terms of metabolism and gene expression, Central Valley mosquitoes show increased activity in oxidoreductase, glutathione metabolism, and the pentose phosphate pathway. Conversely, Rock mosquitoes display signs of metabolic inefficiency and mitochondrial dysregulation, likely tolerated due to the consistency and nutritional abundance of a controlled lab environment. The study also examines Ae. aegypti P450 and GSTE profiles in relation to other insecticide-resistant groups. While metabolomic data can differentiate our study groups, the challenges in biomarker development arise from few detected markers meeting high fold change thresholds.

Mosquito-repellent textiles are classified as protective textiles designed to mitigate the presence of mosquito species recognised as vectors for diseases such as malaria and dengue fever. This study aimed to explore the feasibility of employing a nanoemulsion system containing lemongrass essential oil encapsulated with biopolymers, specifically tragacanth gum and cationic guar gum, as finishing materials on cotton and polyester fabrics. Being anionic biopolymer, tragacanth gum has resulted in outstanding zeta potential, polydispersity index, particle size and encapsulation efficiency with the values of − 38.1 mV, 0.2, 14.1 nm and 99%, respectively. The positively charged guar gum that interacted with aluminium chloride led to precipitation, which disfavoured retention and repellency properties. Based on correlation coefficient (R2) values for tragacanth gum (0.9832) and cationic guar gum (0.9761)-based nanoemulsions, the release of lemongrass essential oil from nanoemulsions followed the Korsmeyer–Peppas kinetic model. Following five cycles of washing and heating, the retention of tragacanth gum-based nanoemulsion on cotton and polyester was determined as 62% and 46%, respectively. From an Excito chamber study, 64% of Aedes aegypti were successfully repelled from nanoemulsion-treated cotton, whereas 53% of the same mosquito species were repelled from nanoemulsion-treated polyester. Overall, results from this study are in line with the mosquito vector control initiative outlined by the World Health Organization. [ABSTRACT FROM AUTHOR]

Arylalkylamine N‐acetyltransferase (aaNAT) is a crucial enzyme that catalyses the transfer of acetyl groups from acetyl coenzyme A to arylalkylamines and arylamines. Evolutionary studies have identified a distinct class of aaNATs specific to mosquitoes, yet their functions remain elusive. This study focuses on Ae‐aaNAT7, a mosquito‐unique gene in Aedes aegypti (Diptera:Culicidae), to explore its functionality. Temporal and spatial expression analysis of Ae‐aaNAT7 mRNA revealed high expression during embryonic development and in first‐instar larvae, with notable expression in the limbs of adult mosquitoes based on tissue expression profiling. By further employing CRISPR/Cas9 technology for loss‐of‐function studies, our investigation revealed a reduction in the area of white spotting in the limbs of Ae‐aaNAT7 mutant adult mosquitoes. Further investigation revealed a significant decrease in the fecundity and hatchability of the mutants. Dissection of the ovaries from Ae‐aaNAT7 heterozygous mutants showed a noticeable reduction in the oocyte area compared with wild type. Dissection of the exochorion of the eggs from Ae‐aaNAT7 homozygous mutants consistently revealed a striking absence of mature embryos. In addition, RNA interference experiments targeting Ae‐aaNAT7 in males resulted in a reduction in fecundity, but no effect on hatchability was observed. These collective insights underscore the substantial impact of Ae‐aaNAT7 on reproduction and its pivotal contribution to adult limb pigmentation in Ae. aegypti. These revelations offer insights pivotal for the strategic design of future insecticide targets. [ABSTRACT FROM AUTHOR]

Aedes aegypti is an important mosquito vector of human disease with a wide distribution across the globe. Climatic conditions and ecological pressure drive differences in the biology of several populations of this mosquito species, including blood‐feeding behaviour and vector competence. However, no study has compared activity and/or sleep among different populations/lineages of Ae. aegypti. Having recently established sleep‐like states in three mosquito species with observable differences in timing and amount of sleep among species, we investigated differences in activity and sleep levels among 17 Ae. aegypti lines drawn from both its native range in Africa and its invasive range across the global tropics. Activity monitoring indicates that all the lines show consistent diurnal activity, but significant differences in activity level, sleep amount, number of sleep bouts and bout duration were observed among the lines. The variation in day activity was associated with differences in host preference and ancestry for the lineages collected in Africa. This study provides evidence that the diurnal sleep and activity profiles for Ae. aegypti are consistent, but there are significant population differences for Ae. aegypti sleep and activity levels and interactions with host species may significantly impact mosquito activity. [ABSTRACT FROM AUTHOR]

Globalisation, climate change and international trade are the factors contributing to the spread of Aedes albopictus (Diptera: Culicidae) and Ae. aegypti into new areas. In newly invaded habitats, these non‐native species can serve as arbovirus disease vectors or increase the risk of disease spill over. These mosquitoes continue to emerge in new areas where they have or will have overlapping ranges with other resident mosquito species. The study investigates how invasive Aedes mosquitoes compete with the native Culex pipiens in Türkiye, which might affect the overall mosquito population dynamics and disease transmission risks. Both Aedes species exhibited contrasting responses to interspecific competition with Cx. pipiens. While Ae. albopictus suffers reduced emergence primarily in larger containers with abundant food, Ae. aegypti surprisingly thrives in mixed cultures under all food conditions. Adult Cx. pipiens emergence drops by half against Ae. albopictus and under specific conditions with Ae. aegypti. Competition influences mosquito size differently across species and life stages. Culex pipiens females grow larger when competing with Ae. aegypti, potentially indicating resource advantage or compensatory strategies. However, Ae. albopictus size shows more nuanced responses, suggesting complex interactions at play. Understanding how invasive and native mosquitoes interact with each other can provide insights into how they adapt and coexist in shared habitats. This knowledge can inform effective control strategies. The study highlights the differential responses of invasive Aedes species and the potential for managing populations based on their competitive interactions with the native Cx. pipiens. It can contribute to improved monitoring and prediction systems for the spread of invasive mosquitoes and the associated disease risks. [ABSTRACT FROM AUTHOR]

Mosquito traps, historically used for surveillance and research, have gained prominence as a tool for mosquito control, amidst concern over the environmental impact and increased resistance to insecticide‐based methods. In this study, we tested the effectiveness of a mass trapping barrier design with two types of traps, Mosquito Magnet (MM) traps and BG‐Protector (BGP) traps. This experiment was conducted in three coastal camping areas in southern France between summer and autumn 2022, where the presence of floodwater mosquito species with anthropophilic preferences like Aedes caspius represents a year‐long nuisance. MM traps were set around the campsite as a barrier to interfere with mosquitoes from entering the campsites, whereas BGP traps were set within the campsites, with the aim of diverting mosquitoes away from humans at peak activity hours. Over 210,000 mosquitoes of 11 species from 4 genera were collected by both trap types across treatment campsites, with no significant differences in mosquito community samplings between BGP and MM traps. Barrier traps effectively targeted Ae. caspius, reducing total mosquito abundance in two of the three study sites by 34% and 55%. This study provides valuable insights into the efficacy and feasibility of using mass trapping barriers as a complementary control strategy for mosquito species in wetlands. [ABSTRACT FROM AUTHOR]

Accurate knowledge of blood meal hosts of different mosquito species is critical for identifying potential vectors and establishing the risk of pathogen transmission. We compared the performance of Miseq next generation sequencing approach relative to conventional Sanger sequencing approach in identification of mosquito blood meals using genetic markers targeting the 12S rRNA and cytochrome oxidase I (COI) genes. We analysed the blood meals of three mosquito vector species (Aedes aegypti, Aedes simpsoni s.l. and Culex pipiens s.l.) collected outdoors, and compared the frequency of single‐ versus multiple‐blood feeding. Single host blood meals were mostly recovered for Sanger‐based sequencing of the mitochondrial 12S rRNA gene, whereas Miseq sequencing employing this marker and the COI marker detected both single and multiple blood meal hosts in individual mosquitoes. Multiple blood meals (two or more hosts) which mostly included humans were detected in 19%–22.7% of Ae. aegypti samples. Most single host blood meals for this mosquito species were from humans (47.7%–57.1%) and dogs (9.1%–19.0%), with livestock, reptile and rodent hosts collectively accounting for 4.7%–28.9% of single host blood meals. The frequency of two or more host blood meals in Ae. simpsoni s.l. was 26.3%–45.5% mostly including humans, while single host blood meals were predominantly from humans (31.8%–47.4%) with representation of rodent, reptile and livestock blood meals (18.2%–68.2%). Single host blood meals from Cx. pipiens s.l. were mostly from humans (27.0%–39.4%) and cows (11.5%–27.36%). Multiple blood meal hosts that mostly included humans occurred in 21.2%–24.4% of Cx. pipiens s.l. samples. Estimated human blood indices ranged from 53%–76% for Ae. aegypti, 32%–82% for Ae. simpsoni s.l. and 26%–61% for Cx. pipiens s.l. and were consistently lower for Sanger‐based sequencing approach compared to Miseq‐based sequencing approach. These findings demonstrate that Miseq sequencing approach is superior to Sanger sequencing approach as it can reliably identify mixed host blood meals in a single mosquito, improving our ability to understand the transmission dynamics of mosquito‐borne pathogens. [ABSTRACT FROM AUTHOR]

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Aedes aegypti are slender, fragile, long-legged mosquito, which are distributed worldwide. In general, it is a terrestrial and nocturnal species that act as pollinator for few plant species as well as it is a hematophagous insect and act as main vector for many arboviruses (dengue, yellow fever, etc.). In many cities of Pakistan, dengue fever is becoming more prevalent as an infectious disease. as there is currently no vaccine for the dengue virus and control of the disease depends on vector control. The present study aims to investigate morphological and molecular identification of Aedes aegypti in district Buner. A total of 365 samples of mosquitoes were randomly collected from six tehsils of the district Buner. Before examination, all the collected samples were preserved in labelled Eppendorf tubes containing silica gel and transported to Veterinary Research & Disease Investigation Center (VR&DIC), Balogram Swat, Khyber Pakhtunkhwa, Pakistan for further laboratory analysis. Morphological identification was performed with the help of stereomicroscope using taxonomical keys. To increase identification accuracy, each sample was reconfirmed by PCR using mitochondrial Cytochrome oxidase first gene (COI). The amplified PCR product was sequenced, and the obtained sequences were trimmed by Bio Edit and BLAST in NCBI. After BLAST, phylogenetic tree was constructed by using MEGA-X. In phylogenetic tree, the sequence (COI) genes of Aedes aegypti species as previously reported from Sri Lanka and India. Furthermore, the results of this study will generate basic information about mosquitos spp; and it will help to understand the epidemiology of Aedes aegypti disease in Khyber Pakhtunkhwa, especially in district Buner, Khyber Pakhtunkhwa, Pakistan. [ABSTRACT FROM AUTHOR]

Valorization of fruit wastes through fermentation yields a multipurpose liquid called jiaosu. This study was conducted to compare the biochemical content changes (pH, total proteins, total carbohydrates, total phenolics, total alcohols, and organic acids) before and after fermentation for three months, as well as to evaluate the antibacterial, antifungal, and mosquito larvicidal activities of three combinations of jiaosu samples, orange-papaya-watermelon (OPW), grapefruit-mango-pineapple (GMP), and durian-jackfruit-passion fruit (DJP). After fermentation, the jiaosu samples were acidic (pH 3.05–3.40). Only GMP and DJP showed increased total protein content (p < 0.05). All samples utilized carbohydrates extensively during fermentation and displayed significant increases (p < 0.05) in total phenolic contents. Alcohols were detected in all samples (2.15% ± 0.05%–8.34% ± 0.06%) after fermentation. All organic acids (oxalic, tartaric, malic, lactic, acetic, citric, and succinic acids) were significantly increased (p < 0.05) in all samples except for the tartaric and succinic acids in OPW which decreased after fermentation. All samples exhibited minimum inhibitory concentrations of 25–50% v/v against five species of human pathogenic bacteria and minimum fungicidal concentrations of 12.5–50% v/v against the fungus Cryptococcus neoformans. All samples showed strong larvicidal activity against the third instar larvae of Aedes spp. mosquitoes. The larvae of Aedes aegypti were more susceptible to the jiaosu samples than Aedes albopictus with the respective median lethal concentrations (LC50) of 2.14–5.16% v/v and 6.52–14.55% v/v, after 24 h post-treatment. The findings from this study recorded the biochemical changes in different fruit peel combinations of jiaosu during fermentation and the potential use of jiaosu as cleaning agent and biopesticide. [ABSTRACT FROM AUTHOR]

BACKGROUND: The incompatible insect technique (IIT) has been used for Aedes mosquito population suppression to curb the transmission of dengue. However, its wide application is limited owing to the low output of male mosquitoes and the risk of population replacement from the release of fertile Wolbachia‐infected females. This study aims to improve IIT efficiency for broader adoption. RESULTS: We assessed the impact of 10% pyriproxyfen (PPF) sticky powder exposure on Wolbachia (from Culex molestus)‐transinfected Aedes albopictus Guangzhou line (GUA line) (GC) mosquitoes. We found that the exposure caused chronic toxicity in adult mosquitoes without affecting the cytoplasmic incompatibility (CI)‐inducing capability of males. The PPF‐contaminated GC females exhibited significant sterilization and the ability to disseminate lethal doses of PPF to breeding sites. Subsequently, we conducted a field trial combining PPF with IIT aiming to suppress the Ae. albopictus population. This combined approach, termed boosted IIT (BIIT), showed a notable enhancement in population suppression efficiency. The improved efficacy of BIIT was attributed to the dispersion of PPF particles in the field via the released PPF‐contaminated male mosquitoes. During the BIIT field trial, no Wolbachia wPip‐positive Ae. albopictus larvae were detected, indicating the effective elimination of the risk of Wolbachia‐induced population replacement. Additionally, the field trial of BIIT against Ae. albopictus resulted in the suppression of the nontarget mosquito species Culex quinquefasciatus. CONCLUSION: Our results highlight the remarkable efficiency and feasibility of combining IIT with PPF in suppressing mosquito populations, facilitating the widespread implementation of IIT‐based management of mosquito‐borne diseases. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The presence of environmental microplastics (MPs) poses a significant threat to terrestrial and aquatic animals, including insects such as blood‐sucking mosquitoes. The paper reports on the laboratory study of the effect of three different types of MPs, including fragmented high‐density polyethylene (HDPE), polypropylene (PP) and polystyrene (PS), on the viability, innate immune responses, activity of detoxifying enzymes and malondialdehyde (MDA) concentration in Aedes aegypti (Linnaeus, 1762). The results showed that dietary administration of microfragments of PP, PS and HDPE at low concentrations (4 mg/L) had no effect on the survival rate of mosquito larvae, but was observed to suppress the larval immune response. The addition of MPs to the diet resulted in a significant suppression of phenoloxidase activity compared to the control. A decrease in the activity of the detoxifying enzymes glutathione‐S‐transferase and non‐specific esterase was observed. Dietary administration of MPs did not cause any significant change in alkaline proteolytic enzyme activity in larvae compared to the control. However, we observed a twofold increase in the activity of acid proteolytic enzymes in all experiments compared to the control (p < 0.05). MDA levels in larval homogenates remained unchanged, while lysozyme‐like activity showed a slight decrease compared to the control. The observed processes may be a consequence of intestinal obstruction by MPs, which may cause microtraumas to intestinal tissues and changes in the structure and composition of the microbiota. These changes may have a profound effect on the resistance of mosquito larvae to insecticides and pathogens. [ABSTRACT FROM AUTHOR]

Macaques are widely distributed in Thailand with remarkable adaptation to living close to humans in residential, religious sites, markets and tourist areas. They play an essential role in the persistence of pathogens in the environment. As reservoir hosts, they are exposed to hematophagous vectors that secrete saliva, a cocktail of bioactive molecules including antigenic components stimulating host antibody production. Subsequent to the detection of mosquito‐borne pathogens in macaques living in national parks, we aimed to determine the seroprevalence of antibodies to crude salivary gland extracts (SGEs) from culicine mosquitoes (Aedes aegypti [Linnaeus, 1762], Ae. albopictus [Skuse, 1895] and Culex quinquefasciatus [Say, 1823]) and compare individual titres between macaque species/national parks (33, Macaca arctoides [I. Geoffroy Saint‐Hilaire, 1831] [Primates: Cercopithecidae] from Kaeng Krachan, 23 M. leonina leonina [Blyth, 1863] [Primates: Cercopithecidae] from Khao Yai and four M. fascicularis [Raffles, 1821] [Primates: Cercopithecidae] from Mu Ko Ranong). The anti‐mosquito SGE antibodies found in 60 macaques from three national parks indicate varying levels of host‐vector exposure. Macaque antibody titres were high against culicine mosquitoes. However, the significant difference among national parks (or macaque species) was only observed against Cx. quinquefasciatus. Correlation analysis of titres between Aedes SGE and arboviruses revealed a significantly more intense immune response against Ae. albopictus in DENV3‐positive M. arctoides. Current findings support the concept of salivary biomarkers using accessible SGE, available from mosquito colonies of interest. However, we observed cross‐reactivity between Aedes species because of crude SGE containing species‐shared proteins. Nevertheless, a potential risk of pathogen transmission is emphasised between national park visitors and macaques via mosquitoes as bridge vectors. This information contributes to preventive measures against mosquito bites, including those implemented in tourist areas. [ABSTRACT FROM AUTHOR]

The control of zoonotic and vector‐borne pathogens is challenging due to the limited availability of intervention tools. West Nile virus (WNV) is an example of a globally distributed zoonotic arbovirus that circulates between Culex species (Diptera: Culicidae) mosquitoes and avian hosts, with spillover transmission to humans, resulting in disease cases. Interventions delivering systemic insecticides to vertebrate hosts used by vector species, known as xenointoxication, are potential tools for managing vector populations by creating toxic bloodmeals. In this study, we evaluated the impact of two systemic pesticides (ivermectin; Ivomec® Pour‐On and fluralaner; Bravecto®), and one anthelmintic (fenbendazole; Safe‐Guard® Aquasol) on the mortality of Cx. quinquefasciatus Say (Diptera: Culicidae). We found no significant difference in the feeding rates of mosquitoes that fed on treated chickens compared with those fed on untreated chickens, suggesting that the treatment did not repel mosquitoes. The mortality of Cx. quinquefasciatus mosquitoes feeding on fluralaner‐treated chickens was significantly higher (p < 0.01) than those fed on control chickens at 3 and 7 days post‐treatment, but this effect was not observed in mosquitoes fed on chickens treated with fenbendazole or ivermectin. No differences in mortality were observed among the groups at 14, 26 or 56 days post‐treatment. These data support fluralaner as a xenointoxication tool to control Cx. quinquefasciatus populations and decrease the risk of human exposure to their associated pathogens. [ABSTRACT FROM AUTHOR]

Background: Wolbachia incompatible insect technique (IIT) programs have been shown in field trials to be highly effective in suppressing populations of mosquitoes that carry diseases such as dengue, chikungunya, and Zika. However, the frequent and repeated release of Wolbachia-infected male mosquitoes makes such programs resource-intensive. While the need for optimization is recognized, potential strategies to optimize releases and reduce resource utilization have not been fully explored. Results: We developed a process-based model to study the spatio-temporal metapopulation dynamics of mosquitoes in a Wolbachia IIT program, which explicitly incorporates climatic influence in mosquito life-history traits. We then used the model to simulate various scale-down and redistribution strategies to optimize the existing program in Singapore. Specifically, the model was used to study the trade-offs between the intervention efficacy outcomes and resource requirements of various release program strategies, such as the total number of release events and the number of mosquitoes released. We found that scaling down releases in existing sites from twice a week to only once a week yielded small changes in suppression efficacy (from 87 to 80%), while requiring 44% fewer mosquitoes and release events. Additionally, redistributing mosquitoes from already suppressed areas and releasing them in new areas once a week led to a greater total suppressive efficacy (83% compared to 61%) while also yielding a 16% and 14% reduction in the number of mosquitoes and release events required, respectively. Conclusions: Both scale-down and redistribution strategies can be implemented to significantly reduce program resource requirements without compromising the suppressive efficacy of IIT. These findings will inform planners on ways to optimize existing and future IIT programs, potentially allowing for the wider adoption of this method for mosquito-borne disease control. [ABSTRACT FROM AUTHOR]

The revival of the transmission dynamics of mosquito-borne diseases grants striking challenges to public health intensified by climate change worldwide. This inclusive review article examines multidimensional strategies and challenges linked to climate change and the epidemiology of mosquito-borne diseases such as malaria, dengue, Zika, chikungunya, and yellow fever. It delves into how the biology, pathogenic dynamics, and vector distribution of mosquitoes are influenced by continuously rising temperatures, modified rainfall patterns, and extreme climatic conditions. We also highlighted the high likelihood of malaria in Africa, dengue in Southeast Asia, and blowout of Aedes in North America and Europe. Modern predictive tools and developments in surveillance, including molecular gears, Geographic Information Systems (GIS), and remote sensing have boosted our capacity to predict epidemics. Integrated data management techniques and models based on climatic conditions provide a valuable understanding of public health planning. Based on recent data and expert ideas, the objective of this review is to provide a thoughtful understanding of existing landscape and upcoming directions in the control of mosquito-borne diseases regarding changing climate. This review determines emerging challenges and innovative vector control strategies in the changing climatic conditions to ensure public health. [ABSTRACT FROM AUTHOR]

Background: The city of Abidjan, Côte d'Ivoire has increasingly faced multiple outbreaks of Aedes mosquito-borne arboviral diseases (e.g., dengue (DEN) and yellow fever (YF)) during the recent years, 2017–2023. Thus, we assessed and compared Aedes aegypti larval and adult population dynamics and Stegomyia indices in four urbanized areas with differential arboviral incidences in Abidjan, Côte d'Ivoire. Methods: From August 2019 to July 2020, we sampled Aedes mosquito immatures (larvae and pupae), adults and breeding habitats in Anono and Gbagba with high arboviral incidences and Ayakro and Entente with low arboviral incidences in the Abidjan city, using standardized methods. Sampling was conducted in the peridomestic and domestic (indoors and outdoors) premises during short dry season (SDS), short rainy season (SRS), long dry season (LDS) and long rainy season (LRS). The abdomens and ovaries of Ae. aegypti females were examined to determine their blood-meal and parity statuses. Stegomyia indices (container index: CI, house index: HI and Breteau index: BI), blood-meal status and parity rates were compared by study sites and seasons and with the World Health Organization (WHO)-established epidemic thresholds. Results: Overall, Aedes and arboviral risk indices were high and similar between the four study areas. In total, 86,796 mosquitoes were identified and dominated by Ae. aegypti species (97.14%, 84,317/86,796). The most productive larval breeding habitats were tires, discarded containers and water storage containers. CI, HI, and BI in Anono (22.4%, 33.5% and 89.5), Ayakro (23.1%, 43.8% and 91.0), Entente (15.9%, 24.8% and 48.5) and Gbagba (23.3%, 43.0% and 102.0) were high in the respective study sites. Stegomyia indices were higher than the WHO-established epidemic thresholds during any seasons for DEN, and LRS and SRS for YF. The numbers of Ae. aegypti-positive breeding sites were higher in the domestic premises (68.0%, 900/1,324) than in the peridomestic premises (32.0%, 424/1,324). In the domestic premises, Ae. aegypti-positive breeding sites (94.6%, 851/4,360) and adult individuals (93.4%, 856/916) were mostly found outdoors of houses. Aedes aegypti adult females were mostly unfed (51.3%, 203/396), followed by blood-fed (22.2%, 88/396), gravid (13.9%, 55/396) and half-gravid (12.6%, 50/396), and had parity rate of 49.7% (197/396) that was comparable between the study sites. Conclusions: The city of Abidjan, Côte d'Ivoire is highly infested with Ae. aegypti which showed comparable ecological patterns across study sites and seasons. Thus, the local communities are exposed to high and permanent risks of transmission of DEN and YF viruses that were above the WHO-established epidemic thresholds throughout. The results provide a baseline for future vector studies needed to further characterize the observed patterns of local Ae. aegypti abundances and behaviors, and risks of transmission of these arboviruses. Community-based larval source management of identified productive containers might reduce Ae. aegypti numbers and risks of transmission of Aedes-borne arboviruses in Abidjan, and other sub-Saharan African cities. Author summary: As most sub-Saharan African cities, Abidjan in Côte d'Ivoire has faced recently a considerable increase in the outbreaks of dengue (DEN) and yellow fever (YF). However, critical data are still lacking on the ecology of the main vector Aedes aegypti and the risk of transmission of DEN and YF viruses. We assessed the ecology of Ae. aegypti mosquitoes and the risk of DEN and YF virus transmission in areas with high and low DEN and YF occurrences in Abidjan. Our findings revealed a significant presence of Ae. aegypti, indicating a high risk of YF and DEN transmission across all study areas. Ae. aegypti larvae were mostly breeding in tires, discarded containers and water storage containers. Meanwhile, elderly adult females were abundant, alongside a significant presence of both unfed host-seeking and blood-fed individuals in and around residences. We observed seasonal risk patterns, with permanent and high threats for DEN observed throughout both rainy and dry seasons over the entire year, alongside elevated risks of YF during both short and long rainy seasons across all study areas. Our findings provide insights into the ecology of Ae. aegypti and the epidemiology of DEN and YF, crucial for strategically targeting and controlling this vector in areas both affected and unaffected by the disease outbreaks. Community-based intervention programs for managing identified larval breeding sites might reduce Ae. aegypti numbers to prevent future outbreaks of DEN and YF in Abidjan and other sub-Saharan African cities. [ABSTRACT FROM AUTHOR]

There is an increasing global burden from chikungunya virus (CHIKV). Bangladesh reported a major epidemic in 2017, but it was unclear whether there had been prior widespread transmission. We conducted a nationally representative seroprevalence survey in 70 randomly selected communities immediately before the epidemic. We found that 69 of 2938 sampled individuals (2.4%) were seropositive to CHIKV. Seropositivity to dengue virus (adjusted odds ratio, 3.13 [95% confidence interval, 1.86–5.27]), male sex (0.59 [.36–.99]), and community presence of Aedes aegypti mosquitoes (1.80 [1.05–3.0]7) were significantly associated with CHIKV seropositivity. Using a spatial prediction model, we estimated that across the country, 4.99 (95% confidence interval, 4.89–5.08) million people had been previously infected. These findings highlight high population susceptibility before the major outbreak and that previous outbreaks must have been spatially isolated. [ABSTRACT FROM AUTHOR]

Ground water tanks are known to be preferred Aedes aegypti oviposition places providing opportunities for adult and larvae control. Therefore, a dual‐effect insecticidal coating (IC) (alphacypermethrin/ pyriproxyfen) with a slow‐release mechanism and safe for users could be applied within Aedes spp. breeding sites, representing a promising option. Bioassays were designed to determine the mortality and sterilizing effects on gravid mosquitoes exposed to IC. The effect of inhibition of emergence was evaluated in eggs, larvae and pupae exposed in different containers. For the water safety assessment concentrations of active ingredients were determined by reverse phase high performance liquid chromatography (RP‐HPLC) and the health risk was calculated. The IC applied to the interior walls of water‐holding containers showed efficacy against Ae. aegypti in terms of high gravid‐female mortality (81% at 24 h, p < 0.01), sterilizing effect (inhibition of oviposition by 63%, p < 0.01) and emergence inhibition (100% in eggs, L3 and L4; 97% in pupae). The offspring rate was reduced [only 0.15 (38/250) new adults emerged per exposed gravid females as against 11.90 per unexposed female (2976/250) at baseline]. Emergence inhibition was recorded up to 12 months and adult mortality >80% up to 6 months. The use of water stored in treated containers, either for washing or drinking, is not expected to pose a health risk to users. IC applied to domestic water containers has dual and complementary action that reduces Ae. aegypti densities (immature and adult stages). This represents baseline information for a cluster randomized efficacy trial in Colombia. [ABSTRACT FROM AUTHOR]

Background: Genetic biocontrol interventions targeting mosquito-borne diseases require the release of male mosquitoes exclusively, as only females consume blood and transmit pathogens. Releasing only males eliminates the risk of increasing mosquito bites and spreading pathogens while enabling effective population control. The aim of this study is to develop robust sex-sorting methods for early larval stages in mosquitoes, enabling scalable male-only releases for genetic biocontrol interventions. Methods: To address the challenge of sex-sorting in the Asian malaria vector Anopheles stephensi, we engineer Sexing Element Produced by Alternative RNA-splicing of a Transgenic Observable Reporter (SEPARATOR). This dominant fluorescent-based method, previously proven effective in Aedes aegypti, exploits sex-specific alternative splicing of a reporter to ensure exclusive male-specific expression early in development. The sex-specific alternative RNA splicing of the doublesex gene was selected as a target for engineering SEPARATOR due to its evolutionary conservation in insects. To expand SEPARATOR's applicability for genetic sexing, we assessed the cross-species sex-specific RNA splicing activity of the An. gambiae doublesex (AngDsx) splicing module in An. stephensi. Male-specific enhanced green fluorescent protein (EGFP) expression was verified throughout the mosquito life cycle using a fluorescent stereomicroscope. Results: Our results confirm that SEPARATOR regulates male-specific EGFP expression in An. stephensi and enables reliable positive male selection from the first instar larval stages. Molecular analysis demonstrates that male-specific EGFP expression is dependent on doublesex sex-specific splicing events. Additionally, the splicing module from An. gambiae operates effectively in An. stephensi, demonstrating evolutionary conservation in sex-specific splicing events between these species. Conclusions: SEPARATOR's independence from sex-chromosome linkage provides resistance to breakage that could be mediated by meiotic recombination and chromosomal rearrangements, making it highly suitable for mass male releases. By enabling precise male selection from the first instar larval stages, SEPARATOR represents a significant advancement that will aid in the genetic biocontrol for Anopheles mosquitoes. [ABSTRACT FROM AUTHOR]

During the recent yellow fever (YF) epidemics in Brazil, human cases were attributed to spillover infections via sylvatic mosquito transmission. Despite YF virus (YFV) transmission in major urban centers with insufficient vaccination coverage and abundant populations of the domestic vector, Aedes aegypti, there was no evidence of human-amplified transmission. Furthermore, the historic absence of YF in Asia, despite abundant Ae. aegypti and an immunologically naive human population, is unexplained. We tested the hypothesis that pre-existing, heterologous flavivirus immunity, specifically from dengue (DENV) and Zika (ZIKV) viruses, limits YFV viremia and transmission by Ae. aegypti. We infected cynomolgus macaques with DENV or ZIKV, then challenged them 6–9 months later with YFV. We then measured viremia and disease and allowed Ae. aegypti mosquitoes to feed during peak macaque viremia. Although prior heterologous immunity had variable effects on disease, DENV and ZIKV immunity consistently suppressed YFV viremia. Despite no statistical difference due to a small sample size, the suppression in viremia led to a significant reduction in Ae. aegypti infection and a lack of transmission potential. These results support the hypothesis that, in DENV- and ZIKV-endemic regions such as South America and Asia, human flavivirus immunity suppresses YFV human amplification potential, reducing the risk of urban outbreaks. Epidemiology of yellow fever suggests that other flaviviruses may provide some level of cross-protection. Here the authors show in a non-human primate model that pre-existing dengue-2 or Zika virus immunity results in lower yellow fever viremia compared to naïve animals, limiting the transmission potential by Aedes aegypti mosquitoes. [ABSTRACT FROM AUTHOR]

Dengue is an arboviral infection found in tropical and subtropical regions transmitted by hematophagous mosquitoes from the genus Aedes spp. and responsible for millions of cases every year. Public campaigns and educational curriculum are designed to educate people, including children. However, what has been reported is that many decide not to follow these guidelines, even though they allegedly know what has to be done. To understand this phenomenon, this study aims to identify psychological barriers behind the adoption of pro-environmental behaviors that seek to reduce Aedes aegypti 's population. For that, middle school students participated on two studies responsible for (1) adapting the Dragons of Inaction Psychological Barrier (DIPB) scale to the target group (n = 150) and then (2) testing it on a larger group (n = 449). In the exploratory factor analysis, Bartlett correlation (p < 0.001), Cronbach's alpha (0.83), and KMO analysis (overall MSA = 0.84) showed that data was suited for factor analysis. Five factors were retained by Kaiser Criterion and scree test (i.e., Conflicting goals and unnecessary changes— α 0.76, Interpersonal relations— α 0.72, Conflicting goals and lacking knowledge— α 0.58, Tokenism—α 0.73, and Tokenism toward the government— α 0.66). After that, the scale was tested across 11 different schools, where students also answered a questionnaire about the mosquito. Results suggested that the factors Conflicting goals and lacking knowledge and Tokenism toward the government presented a higher level of agreement for all students (means: 2.6 and 2.12 out of five, respectively). Those who scored higher in the mosquito's questionnaire had factors Conflicting goals and unnecessary change and Interpersonal relations inhibited when compared to others (p < 0.05). These results suggests that future educational campaigns should build different actions that focuses on addressing both internal and external factors, creating a mosaic of projects, with different goals, each aiming different environmental challenges. [ABSTRACT FROM AUTHOR]

Background: Dengue is an emerging disease in Argentina due to the colonization of Aedes aegypti, the mosquito vector. Buenos Aires Province is the biggest and most populated district in Argentina, suffering dengue outbreaks of growing magnitude. During epidemic periods, pyrethroid insecticides are used in this country to control adult mosquitoes. Pyrethroid resistance in dengue vectors has been reported worldwide, making it necessary to implement resistance management strategies. The voltage-gated sodium channel is the target site of pyrethroids. Mutations in the gene encoding this protein, called kdr mutations, are usually the molecular cause of pyrethroid resistance in insects. In Ae. aegypti from the Americas, three kdr substitutions were described: V410L, V1016I, and F1534C. The diagnostic of kdr mutations is recommended for the early detection of pyrethroid resistance as well as the consequent planning of evidence-based control policies. Methods: We distributed ovitraps across 16 localities in Buenos Aires Province, collecting 22,123 eggs. A total of 522 mosquitoes were genotyped in positions 1016 and 1534 of voltage-gated channel using multiplex high-resolution melting and/or TaqMan probe methods. A subset of 449 samples was also genotyped by a singleplex high-resolution melting method developed ad hoc and/or Sanger sequencing. Results: We have documented, for the first time to our knowledge in the central region of Argentina, the presence of the 1016Ikdr + 1534Ckdr allele. Additionally, our study reports the first identification of the V410L mutation in central Argentina. These results underscore a growing trend of pyrethroid resistance in Ae. aegypti, fueled by the widespread use of these insecticides. Conclusions: We detected 1016Ikdr + 1534Ckdr and 410Lkdr mutations in central Argentina for the first time and improved the processivity and accuracy of kdr genotyping methods. The results are both a tool for resistance monitoring and a sign of alarm to direct efforts towards finding sustainable methods for vector control to complement or replace pyrethroids. Joint efforts between academia and authorities to develop and implement public policies for vector control are a productive way to transfer scientific results for their application in public health. [ABSTRACT FROM AUTHOR]

The Zika virus epidemic of 2015–16, which caused over 1 million confirmed or suspected human cases in the Caribbean and Latin America, was driven by a combination of movement of infected humans and availability of suitable habitat for mosquito species that are key disease vectors. Both human mobility and mosquito vector abundances vary seasonally, and the goal of our research was to analyze the interacting effects of disease vector densities and human movement across metapopulations on disease transmission intensity and the probability of super-spreader events. Our research uses the novel approach of combining geographical modeling of mosquito presence with network modeling of human mobility to offer a comprehensive simulation environment for Zika virus epidemics that considers a substantial number of spatial and temporal factors compared to the literature. Specifically, we tested the hypotheses that 1) regions with the highest probability of mosquito presence will have more super-spreader events during dry months, when mosquitoes are predicted to be more abundant, 2) regions reliant on tourism industries will have more super-spreader events during wet months, when they are more likely to contribute to network-level pathogen spread due to increased travel. We used the case study of Colombia, a country with a population of about 50 million people, with an annual calendar that can be partitioned into overlapping cycles of wet and dry seasons and peak tourism and off tourism seasons that drive distinct cyclical patterns of mosquito abundance and human movement. Our results show that whether the first infected human was introduced to the network during the wet versus dry season and during the tourism versus off tourism season profoundly affects the severity and trajectory of the epidemic. For example, Zika virus was first detected in Colombia in October of 2015. Had it originated in January, a dry season month with high rates of tourism, it likely could have infected up to 60% more individuals and up to 40% more super-spreader events may have occurred. In addition, popular tourism destinations such as Barranquilla and Cartagena have the highest risk of super-spreader events during the winter, whereas densely populated areas such as Medellín and Bogotá are at higher risk of sustained transmission during dry months in the summer. Our research demonstrates that public health planning and response to vector-borne disease outbreaks requires a thorough understanding of how vector and host patterns vary due to seasonality in environmental conditions and human mobility dynamics. This research also has strong implications for tourism policy and the potential response strategies in case of an emergent epidemic. Author summary: The Zika virus pandemic of 2015–16, which caused over 1 million human cases in the Caribbean and Latin America, was driven by a combination of movement of infected humans and presence of mosquito species, such as Aedes aegypti, that carry the disease. Both human mobility and mosquito vector densities vary seasonally, and the goal of our research was to analyze the interacting effects of disease vector presence and human movement across metapopulations on disease transmission intensity and the probability of super-spreader events. Specifically, we tested the hypotheses that 1) regions with the highest probability of mosquito presence will have more super-spreader events during dry months, when mosquitoes are predicted to be more abundant, 2) regions reliant on tourism industries will have more super-spreader events during wet months, as they are more likely to contribute to network-level pathogen spread due to increased travel. We used the case study of Colombia, a nation with a population of about 50 million people, whose annual calendar can be partitioned into overlapping cycles of wet and dry seasons and tourism and off-tourism seasons that drive distinct cyclical patterns of mosquito occurrence and human movement. Our approach combined spatial modeling of mosquito presence with network modeling of human mobility. We used a Maximum Entropy model to estimate the spatially and temporally varying habitat suitability for Aedes aegypti, the primary mosquito vector of Zika virus in Colombia, in terms of environmental factors such as temperature, precipitation, and vegetation coverage and human factors indicating land use and development, socioeconomic status, and prevalence of standing water that provides key habitat for juvenile mosquitoes. We also used airline travel data to develop metapopulation patch network models of the 1,123 municipalities of Colombia for each month of 2015 and 2016. We combined our vector habitat suitability and human mobility network models to simulate the Zika virus epidemic if it had begun in each month of 2015. Our results show that whether the first human case was introduced to the network during the wet vs. dry season and during the tourism vs. off-tourism season profoundly affects the severity and trajectory of the epidemic. For example, Zika virus was first detected in Colombia in October of 2015. Had it originated in January, a dry season month with high rates of tourism, it likely could have infected up to 30% more individuals and up to 40% more super-spreader events may have occurred. In addition, popular vacation spots such as Barranquilla and Cartageña have the highest risk of super-spreader events during the winter, whereas densely populated areas such as Medellín and Bogotá are at higher risk of sustained transmission during dry months in the summer. Our research demonstrates that public health planning and response to vector-borne disease outbreaks requires a thorough understanding of how vector and host patterns vary due to seasonality in environmental conditions and human mobility dynamics. [ABSTRACT FROM AUTHOR]

Temperature and water availability significantly influence mosquito population dynamics. We have developed a method, integrating experimental data with insights from mosquito and thermal biology, to calculate the basic reproduction number (RM) for urban mosquito species Aedes albopictus and Aedes aegypti. RM represents the number of female mosquitoes produced by one female during her lifespan, indicating suitability for growth. Environmental conditions, including temperature, rainfall and human density, influence RM by altering key mosquito life cycle traits. Validation using data from Spain and Europe confirms the approach's reliability. Our analysis suggests that temperature increases may not uniformly benefit Ae. albopictus proliferation but could boost Ae. aegypti expansion. We suggest using vector RM maps, leveraging climate and environmental data, to predict areas susceptible to invasive mosquito population growth. These maps aid resource allocation for intervention strategies, supporting effective vector surveillance and management efforts. [ABSTRACT FROM AUTHOR]

Background: The decision to imbibe a blood meal is predominantly dependent on the sensitivity and specificity of haematophagous arthropods to blood-derived adenine nucleotides, in particular adenosine triphosphate (ATP). Despite previous efforts to identify and characterise the specificity and sensitivity to ATP and other adenine nucleotides, as well as the role of other blood-derived phagostimulants across the Culicidae, comparisons across species remain difficult. Methods: The feeding response of the yellow fever mosquito Aedes aegypti and the African malaria vector Anopheles gambiae to adenine nucleotides in the presence of a carbonate buffer was assessed using a membrane feeding assay. The proportion of mosquitoes engorged and the volume imbibed by all mosquitoes was scored visually and spectrophotometrically. In addition, the proportion of prediuresing An. gambiae, as well as the volume engorged and prediuresed, was examined. Results: Aedes aegypti was more sensitive to adenine nucleotides than An. gambiae, but both species maintained specificity to these phagostimulants, demonstrating a dose-dependent bimodal feeding pattern, thereby expanding our understanding of the all-or-none blood-feeding hypothesis. Feeding on the bicarbonate buffer by An. gambiae—but not that of Ae. aegypti—demonstrated a species-specific variation in how blood phagostimulants are encoded. Adenine nucleotides, with and without bovine serum albumin, were observed to dose-dependently regulate the proportion of An. gambiae prediuresing and the volumes prediuresed but not volumes engorged. Conclusions: Taken together, the results of this study expand our understanding of how mosquitoes differentially assess and respond to blood meal constituents, and provide a basis for further physiological and molecular studies. [ABSTRACT FROM AUTHOR]

Wolbachia pipientis (= Wolbachia) has promise as a tool to suppress virus transmission by Aedes aegypti mosquitoes. However, Wolbachia can have variable effects on mosquito-borne viruses. This variation remains poorly characterized, yet the multimodal effects of Wolbachia on diverse pathogens could have important implications for public health. Here, we examine the effects of transient somatic infection with two strains of Wolbachia (wAlbB and wMel) on the alphaviruses Sindbis virus (SINV), O'nyong-nyong virus (ONNV), and Mayaro virus (MAYV) in Ae. aegypti. We found variable effects of Wolbachia including enhancement and suppression of viral infections, with some effects depending on Wolbachia strain. Both wAlbB- and wMel-infected mosquitoes showed enhancement of SINV infection rates one week post-infection, with wAlbB-infected mosquitoes also having higher viral titers than controls. Infection rates with ONNV were low across all treatments and no significant effects of Wolbachia were observed. The effects of Wolbachia on MAYV infections were strikingly strain-specific; wMel strongly blocked MAYV infections and suppressed viral titers, while wAlbB had more modest effects. The variable effects of Wolbachia on vector competence underscore the importance of further research into how this bacterium impacts the virome of wild mosquitoes including the emergent human pathogens they transmit. Author summary: In recent years, wild populations of Aedes aegypti mosquitoes in over a dozen countries have been deliberately infected with Wolbachia pipientis ("Wolbachia"); an intracellular bacterium that, in some circumstances, helps to curb the spread of mosquito-brone pathogens including dengue virus. But how does Wolbachia affect the ability of mosquitoes to become infected with and spread the many different viruses they encounter in nature? Here, we use transient somatic infections in Aedes aegypti to characterize the effects of Wolbachia on three different alphaviruses that cause illness in humans: Sindbis virus, O'nyong-nyong virus, and Mayaro virus. We find that transient Wolbachia infections have variable effects on these different pathogens, ranging from significant suppression of Mayaro virus to significant enhancement of Sindbis virus. Our research has important implications for the design of vector control strategies, and suggests further research is needed to understand how Wolbachia shapes the replication and transmission of diverse viruses in mosquitoes. [ABSTRACT FROM AUTHOR]

Simple Summary: Our research delved into the potential of using the Varian Clinac 23EX linear accelerator, typically employed in X-ray cancer treatment, as an alternative radiation source for the sterile insect technique (SIT) in mosquito control. Through our investigation, we found that by adjusting the X-ray dosage to a specific threshold, the resulting sterilization effect rivaled that achieved by traditional γ-ray sources. For example, at a dose of 60 Gy of X-rays and 40 Gy of γ-rays, the egg hatch rate can even be as low as 0.3%, which can result in induced sterility (IS) of 99.6%. This breakthrough opens up a convenient avenue for researchers, granting them access to readily available radiotherapy equipment for SIT studies. By leveraging the existing infrastructure, such as radiotherapy facilities, researchers can expedite their SIT research endeavors, potentially revolutionizing mosquito control efforts. The integration of radiotherapy equipment into SIT studies promises to propel advancements in this field, facilitating faster progress and fostering eco-friendly approaches to insect population management. The sterile insect technique (SIT) stands as an eco-friendly approach for mosquito control, but it is impeded by the limited availability of γ-ray radiation source. This research sought to investigate a different radiation source—the Varian Clinac 23EX linear accelerator, which is frequently used for X-ray therapy in cancer treatment. Evaluation parameters including emergence rate, average survival time, induced sterility (IS), male mating competitiveness of irradiated males and fecundity (the number of eggs per female per batch), and the egg hatch rate of females mated with irradiated males were assessed to gauge the application potential of this cancer treatment equipment in the realm of the SIT. The results indicated that X-rays from radiation therapy equipment can effectively suppress the hatch rate of offspring mosquitoes without adversely affecting the emergence rate of irradiated males or the fecundity of females. In addition, at an X-ray dose of 60 Gy, the induced sterility in Ae. aegypti was comparable to the sterility induced by 40 Gy of γ-rays with both treatments resulting in 99.6% sterility. Interestingly, when a release ratio of 7:1 (irradiated males:unirradiated males) was used to competitively mate with females, the IS results resulted by 60 Gy X-rays and 40 Gy γ-rays were still at 70.3% and 73.7%, respectively. In conclusion, the results underscored the potential of the Varian Clinac 23EX linear accelerator as an X-ray source in SIT research. [ABSTRACT FROM AUTHOR]

Simple Summary: In Aedes aegypti, resistance to pyrethroid insecticides is widespread and has been strongly linked to the presence of mutations in the voltage-gated sodium channel. Distinct ensembles of these mutations are found in the Western Hemisphere and Indopacific with little known mixing. The Indopacific mutations have not previously been detected in the USA. We detected the presence of the V1016G and S989P mutations in three recent collections from Osceola County, Florida. These findings were confirmed using multiple methods and represent a significant expansion of the geographic range of these resistance factors. This requires the modification of the existing resistance screening protocols and further work to understand the operational implications for mosquito control. Aedes aegypti is a major arboviral disease vector and is therefore a critical target for control by public health programs. Early eradication efforts have shown that Ae. aegypti can rapidly build insecticide resistance, and, now, resistance to pyrethroids, the major class of adulticides used for operational control, is common in many populations. A major contributor to this resistance is a group of knockdown resistance (kdr) SNPs that normally exist in distinct ensembles in the Western Hemisphere and the Indopacific with little known mixing. In this study, we detected, and confirmed, using multiple methods, the Indopacific kdr SNPs, both V1016G and S989P, in three recent collections from Osceola County, Florida. This represents a large expansion of the geographic range of the Indopacific kdr SNPs. We consider the implications of this finding on future insecticide resistance surveillance studies, including assessing the ability of our current screening tools to detect these SNPs. We find that the presence of the Indopacific SNPs requires the modification of existing resistance screening protocols and requires further work to understand the operational implications for mosquito control. [ABSTRACT FROM AUTHOR]

Pyriproxyfen is a pesticide used in Brazil to control the Aedes aegypti mosquito, vector of arboviruses like Zika and dengue. However, this pesticide is structurally similar to retinoic acid, a metabolite of vitamin A that regulates neuronal differentiation and hindbrain development during the embryonic period. Due to the similarity between pyriproxyfen and retinoic acid, studies indicate that this pesticide may have cross‐reactivity with retinoid receptors. Thus, pregnant exposure to pyriproxyfen could interfere in the nervous system development of the fetal. In this context, the present study evaluated whether prenatal exposure to pyriproxyfen affects neonatal development and brain structure in rats. Wistar rat pups were divided in three experimental groups: (1) negative control (CT−)—offspring of rats that drink potable water during pregnancy; (2) pyriproxyfen (PIR)—offspring of rats exposed to Sumilarv® prenatally, a pesticide that has pyriproxyfen as active ingredient; and (3) positive control (CT+)—offspring of rats exposed to an excess of vitamin A prenatally. Only vitamin A treated‐pregnant showed lower weight gain, but gestation length was similar among pregnant that received potable water, water containing vitamin A and water containing Sumilarv. In relation to the offspring, PIR group exhibits a delayed front‐limb suspension response but performed early the negative geotaxis reflex. On the other hand, CT+ group exhibited lower body weight in the 1st postnatal day, delayed audio startle response, but performed early the eyelids opening and hindlimb placing response. A reduction in the maximum brain width was observed both in PIR and CT+ groups, but a reduction in the number of neurons in the M1 cortex was showed only in CT+ group. The number of glial cells in this brain area was similar between the three experimental groups studied. Although prenatal exposure to pyriproxyfen did not alter neonatal milestones in the same way as vitamin A in excess, both substances caused a reduction in the maximum width of the brain, suggesting that this pesticide can produce neurotoxic effects during the embryonic period. [ABSTRACT FROM AUTHOR]

Aedes aegypti is a mosquito species known for its role in transmitting dengue fever, a viral disease prevalent in tropical and subtropical regions. Recognizable by its white markings and preference for urban habitats, this mosquito breeds in standing water near human dwellings. A promising approach to combat the proliferation of mosquitoes is the use of smart traps, equipped with advanced technologies to attract, capture, and monitor them. The most significant results include 97% accuracy in detecting Aedes aegypti, 100% accuracy in identifying bees, and 90.1% accuracy in classifying butterflies in the laboratory. Field trials successfully validated and identified areas for continued improvement. The integration of technologies such as Internet of Things (IoT), cloud computing, big data, and artificial intelligence has the potential to revolutionize pest control, significantly improving mosquito monitoring and control. The application of machine learning (ML) algorithms and computer vision for the identification and classification of Aedes aegypti is a crucial part of this process. This article proposes the development of a smart trap for selective control of winged insects, combining IoT devices, high-resolution cameras, and advanced ML algorithms for insect detection and classification. The intelligent system features the YOLOv7 algorithm (You Only Look Once v7) that is capable of detecting and counting insects in real time, combined with LoRa/LoRaWan connectivity and IoT system intelligence. This adaptive approach is effective in combating Aedes aegypti mosquitoes in real time. [ABSTRACT FROM AUTHOR]

This study investigates the efficacy of three different olfactory cues - cyclohexanone, linalool oxide (LO), and 6-methyl-5-heptan-2-one (sulcatone) - in attracting Aedes aegypti, the primary vector of dengue, using BG sentinel traps in a dengue-endemic area (urban Ukunda) in coastal Kenya. Two experiments were conducted. Experiment 1 compared solid formulations of the compounds in polymer beads against liquid formulations with hexane as the solvent. CO2-baited traps served as controls. In Experiment 2, traps were baited with each compound in the polymer beads, commercial BG-Lure, and CO2. Our results indicate that CO2-baited traps recorded the greatest Ae. aegypti captures in both Experiment 1 and 2, whereas trap captures with polymer beads and solvent-based treatments were comparable. In experiment 2, polymer bead-based treatments yielded significantly greater female captures, each recording ~ 2-fold more captures than traps baited with the BG-Lure. There was no significant difference, however, between the treatments. Female Ae. aegypti captured in CO2-baited traps were mainly unfed (91%), with fewer gravid mosquitoes (6.4%) compared to traps with test compounds (range; 12.7–21.1%). Male captures were lower in LO and BG-Lure baited traps compared to other treatments. Gravimetric analysis showed LO had a slower release rate compared to other compounds. The findings suggest that host-associated compounds loaded on polymer beads are more effective in trapping Ae. aegypti than commercial BG-Lure and reveal sex-specific differences in mosquito responses. These results have implications for mosquito surveillance and control programs, highlighting the potential for selective trapping strategies. [ABSTRACT FROM AUTHOR]

Aedes aegypti, the vector for dengue, chikungunya, yellow fever, and Zika, poses a growing global epidemiological risk. Despite extensive research on Ae. aegypti's life history traits and behavior, critical knowledge gaps persist, particularly in integrating these findings across varied experimental contexts. The plasticity of Ae. aegypti's traits throughout its life cycle allows dynamic responses to environmental changes, yet understanding these variations within heterogeneous study designs remains challenging. A critical aspect often overlooked is the impact of using lab-adapted lines of Ae. aegypti, which may have evolved under laboratory conditions, potentially altering their life history traits and behavioral responses compared to wild populations. Therefore, incorporating field-derived populations in experimental designs is essential to capture the natural variability and adaptability of Ae. aegypti. The relationship between larval growing conditions and adult traits and behavior is significantly influenced by the specific context in which mosquitoes are studied. Laboratory conditions may not replicate the ecological complexities faced by wild populations, leading to discrepancies in observed traits and behavior. These discrepancies highlight the need for ecologically relevant experimental conditions, allowing mosquito traits and behavior to reflect field distributions. One effective approach is semi-field studies involving field-collected mosquitoes housed for fewer generations in the lab under ecologically relevant conditions. This growing trend provides researchers with the desired control over experimental conditions while maintaining the genetic diversity of field populations. By focusing on variations in life history traits and behavioral plasticity within these varied contexts, this review highlights the intricate relationship between larval growing conditions and adult traits and behavior. It underscores the significance of transstadial effects and the necessity of adopting study designs and reporting practices that acknowledge plasticity in adult traits and behavior, considering variations due to larval rearing conditions. Embracing such approaches paves the way for a comprehensive understanding of contextual variations in mosquito life history traits and behavior. This integrated perspective enables the synthesis of research findings across laboratory, semi-field, and field-based investigations, which is crucial for devising targeted intervention strategies tailored to specific ecological contexts to combat the health threat posed by this formidable disease vector effectively. [ABSTRACT FROM AUTHOR]

Natural products are thoroughly studied as valuable alternatives to synthetic insecticides. Heracleum persicum Desf. ex Fisch. (Apiaceae), commonly known as Golpar, is an Iranian medicinal plant largely employed as a spice, which has previously revealed insecticidal potential. The chemical composition of H. persicum essential oil (EO) was investigated by GC-MS and was mainly dominated by hexyl butyrate (36.1%) and octyl acetate (23.7%). The EO and its main esters were tested on three mosquito species. Aedes aegypti (L.) larvae were the most sensitive to all tested products. Lethal concentrations (LC50) of 59.09, 53.59, and 47.05 ppm were recorded for the EO, hexyl butyrate, and octyl acetate, respectively. Aedes albopictus (Skuse) and Anopheles gambiae Giles demonstrated comparable sensitivity to the EO, with LC50 values of 102.97 and 97.91 ppm, respectively, whereas the isolated constituents appeared more active on An. gambiae (LC50 of hexyl butyrate and octyl acetate of 70.97 and 60.71 ppm, respectively) with respect to Ae. albopictus (LC50 of hexyl butyrate and octyl acetate of 85.40 and 91.38 ppm, respectively). Low toxicity was registered for both EO and single components against human embryonic kidney (HEK293) cells. Overall, the H. persicum EO, hexyl butyrate, and octyl acetate could be further considered for larvicide development. [ABSTRACT FROM AUTHOR]

BACKGROUND: Controlling the spread of arboviral diseases remains a considerable challenge due to the rapid development of insecticide resistance in Aedes mosquitoes. This study evaluated the effects of boric acid‐containing toxic sugar bait (TSB) on field populations of resistant Aedes aegypti mosquitoes. In addition, this study examined the flight activity and wing beat frequency and amplitude of males and the flight activity, fecundity, and insemination of females after pairing with males exposed to TSB. The population dynamics of Aedes mosquitoes under imbalanced sex ratios were examined to simulate realistic field conditions for male suppression under the effect of TSB. RESULTS: The mortality of male mosquitoes was consistently high within 24 h after exposure. By contrast, the mortality of female mosquitoes was inconsistent, with over 70% mortality observed at 168 h. The flight activity and wing beat amplitude of treated males were significantly lower than those of controls, but no significant difference in wing beat frequency was detected. The fecundity and insemination of treated female mosquitoes were lower than those of controls. A simulation study indicated that considerably low male population densities led to mating failures, triggering a mate‐finding Allee effect and resulting in persistently low population levels. CONCLUSION: Boric acid‐containing TSB could effectively complement current chemical intervention approaches to control resistant mosquito populations. TSB is effective in reducing field male populations and impairing male flight activity and female‐seeking behavior, resulting in decreased fecundity and insemination. Male suppression due to TSB potentially results in a small mosquito population. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: This study investigated the behavioral responses and toxicity of three basic amines: 1‐methylpiperazine, 1‐methylpyrrolidine, and triethylamine (TEA), compounds suggested previously to be anosmic in vapor exposures to caged mosquitoes. RESULTS: These compounds showed repellency of Aedes aegypti mosquitoes, followed by flightlessness, knockdown, and paralysis, all increasing with exposure time and dosage. Electrophysiological experiments showed a blocking effect on nerve discharge of the Drosophila melanogaster larval central nervous system (CNS) with little evidence of hyperexcitation. Blockage of voltage‐gated (Kv2) potassium channel currents under patch clamp occurred at similar concentrations. Involvement of K+ channels in the action of basic amines was supported by behavior and CNS recordings of a Shaker Kv1 mutant exposed to TEA, where instead of blockage, a hyperexcitation of nerve firing was observed. Experiments on cockroach leg mechanoreceptors demonstrated neuronal excitation and on mosquito antennae strong electroantennogram (EAG) signals with an augmentation of blank air responses after a single puff of basic amine. CONCLUSIONS: The neurophysiological effects of basic amines are consistent with K+ channel block, whereas the antennal EAG response was not obviously associated with anosmia. The low‐dose effects of basic amines appear to be repellency and bradykinesia. Overall, the findings provide key insights into the mechanisms underlying the biological activity of basic amines. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: In 2008–2010, Malaysia experienced a nationwide chikungunya virus (CHIKV) outbreak caused by the Indian Ocean lineage E1-226V (valine) variant, adapted to Aedes albopictus. In 2017–2022, transition to an E1-226A (alanine) variant occurred. Ae. albopictus prevails in rural areas, where most cases occurred during the E1-226V outbreak, while Ae. aegypti dominates urban areas. The shift in circulating CHIKV variants from E1-226V to E1-226A (2009–2022) was hypothesized to result in a transition from rural to urban CHIKV distribution, driven by differences in Ae. aegypti vector competence for the two variants. This study aimed to: (1) map the spatiotemporal spread of CHIKV cases in Malaysia between 2009–2022; and (2) compare replication of E1-226A and E1-226V variants in the midguts and head/thoraxes of Ae. aegypti. Methodology/Principal findings: Spatiotemporal analysis of national notified CHIKV case addresses was performed. Between 2009–2022, 12,446 CHIKV cases were reported, with peaks in 2009 and 2020, and a significant shift from predominantly rural cases in 2009–2011 (85.1% rural), to urban areas in 2017–2022 (86.1% urban; p<0.0001). Two Ae. aegypti strains, field-collected MC1 and laboratory Kuala Lumpur (KL) strains, were fed infectious blood containing constructed CHIKV clones, pCMV-p2020A (E1-226A) and pCMV-p2020V (E1-226V) to measure CHIKV replication by real-time PCR and/or virus titration. The pCMV-p2020A clone replicated better in Ae. aegypti cell line Aag2 and showed higher replication, infection and dissemination efficiency in both Ae. aegypti strains, compared to pCMV-p2020V. Conclusions/Significance: This study revealed that a change in circulating CHIKV variants can be associated with changes in vector competence and outbreak epidemiology. Continued genomic surveillance of arboviruses is important. Author summary: Chikungunya virus (CHIKV) causes fever, rash and joint pain in humans. CHIKV is spread by bites of infected Aedes (Ae.) aegypti and Ae. albopictus mosquitoes. In 2008–2010, CHIKV with an E1-226V mutation became highly adapted to Ae. albopictus and caused global outbreaks. In Malaysia, these major outbreaks occurred mainly in rural areas where this mosquito is most common. We found that a resurgence of CHIKV in 2017–2022 was associated with a different variant with an E1-226A mutation, which had a greater ability to replicate in the Ae. aegypti mosquito than the previous E1-226V variant. This mosquito is found mainly in urban areas, and by looking at geographical locations of reported CHIKV cases, we found that the case distribution had also shifted from rural to predominantly urban areas in 2017–2022. Genetic surveillance of CHIKV and other mosquito-borne viruses is important to identify genetic changes that may affect virus ability to infect different vectors, and disease numbers and distribution. [ABSTRACT FROM AUTHOR]

Background: Tanzania has experienced multiple dengue outbreaks between 2010 and 2019, caused by various dengue virus (DENV) strains. In 2019, there were 6917 confirmed dengue cases and 13 deaths in Tanzania. Routine diagnosis of dengue fever is unfortunately excluded, particularly during non-outbreak periods, resulting in delayed outbreak detection and control. The aim of this study was to improve early detection and control measures for DENV by investigating its circulation in human and Aedes aegypti (A.aegypti) mosquitoes during the non-outbreak periods in Dar es Salaam, Tanzania, which is an area frequently affected by dengue outbreaks. Methods: Four hundred and fifteen (415) blood samples were collected from patients attending randomly selected health facilities in five wards; Azimio, Keko, Mtoni, Mbagala and Chamazi within Temeke district. The samples were tested for DENV NS1 antigen and anti-dengue IgM and IgG antibodies by rapid test. Then, 150 out of 415 blood samples were tested for the DENV by conventional Reverse Transcriptase Polymerase Chain Reaction (RT-PCR). Two thousand two hundred and fifty (2,250) adult female A.aegypti mosquitoes were collected using a Prokopack aspirator and BG sentinel trap or obtained after rearing immature stages and tested, in pools of 15 for DENV by RT-PCR. Statistical Software, SPSS version 23, was used for data analysis. Results: Of the tested blood samples, 17% (71/415) were positive by NS1 antigen, 0.5% (2/415) by IgM, 0.5% (2/415) by IgG antibodies, and 0.5% (2/415) by IgM and IgG. None of the samples tested positive by DENV RT-PCR. Moreover, 3.3% (5/150) of tested mosquito pools had DENV by RT-PCR. Individuals aged between 21 and 40 years of age had increased risk of testing positive for DENV NS1 antigen, followed by those aged 5–20 years old, particularly those residing from Azimio ward, Keko ward, Mtoni ward and Mbagala ward, p-value ≤ 0.05. Conclusion: Findings from this study revealed evidence of DENV circulation during non-outbreak periods in Dar es Salaam, Tanzania. These findings underscore the importance of including testing for dengue infection in routine differential diagnoses of febrile cases, and also frequent dengue surveillance in mosquitos. This proactive approach will help early DENV outbreak detection and control in the country. [ABSTRACT FROM AUTHOR]

Background: Dengue virus (DENV) infection, spread by Aedes aegypti mosquitoes, is a significant public health concern in tropical and subtropical regions. Among the four distinct serotypes of DENV (DENV-1 to DENV-4), DENV-2 is associated with the highest number of fatalities worldwide. However, there is no specific treatment available for dengue patients caused by DENV-2. Objective: This study aimed to identify inhibitory phytocompounds in silico in Vernonia cinerea (V. cinerea), a widely used traditional medicinal plant, for treating DENV-2 associated illnesses. Methods: The chemical structures of 17 compounds from V. cinerea were sourced from the Indian Medicinal Plants, Phytochemistry, and Therapeutics (IMPPAT) database. These compounds underwent geometry optimization, were screened against nonstructural protein 1 (NSP1) of DENV-2, and further validated through molecular dynamics simulations (MDS). Baicalein, an established drug against DENV-2, was used for validation in molecular screening, MDS, and MM-GBSA analyses. Results: Among these compounds, Beta-amyrin, Beta-amyrin acetate, Chrysoeriol, Isoorientin, and Luteolin showed promising potential as inhibitors of the NSP1 of DENV-2, supported by the results of thermodynamic properties, molecular orbitals, electrostatic potentials, spectral data and molecular screening. Besides, these compounds adhered to the Lipinski's "rule of 5", showing no hepatotoxicity/cytotoxicity, with mixed mutagenicity, immunotoxicity, and carcinogenicity. Furthermore, final validation through MDS confirmed their potential, demonstrating stable tendencies with significant inhibitory activities against NSP1 of DENV-2 over the control drug Baicalein. Among the screened compounds, Chrysoeriol emerged as the most promising inhibitor of NSP1 of DENV-2, followed by Luteolin and Isoorientin. Conclusion: Taken together, our results suggest that Chrysoeriol is the best inhibitor of NSP1 of DENV-2, which could be evaluated as a therapeutic agent or a lead compound to treat and manage DENV-2 infections. [ABSTRACT FROM AUTHOR]

Background: Aedes aegypti presence, human-vector contact rates, and Aedes-borne virus transmission are highly variable through time and space. The Lower Rio Grande Valley (LRGV), Texas, is one of the few regions in the U.S. where local transmission of Aedes-borne viruses occurs, presenting an opportunity to evaluate social, urbanistic, entomological, and mobility-based factors that modulate human exposure to Ae. aegypti. Methodology & Principal findings: Mosquitoes were collected using BG-Sentinel 2 traps during November 2021 as part of an intervention trial, with knowledge, attitudes, and practices (KAP) and housing quality surveys to gather environmental and demographic data. Human blood samples were taken from individuals and a Bitemark Assay (ELISA) was conducted to quantify human antibodies to the Ae. aegypti Nterm-34kDa salivary peptide as a measure of human exposure to bites. In total, 64 houses were surveyed with 142 blood samples collected. More than 80% of participants had knowledge of mosquito-borne diseases and believed mosquitoes to be a health risk in their community. Our best fit generalized linear mixed effects model found four fixed effects contributed significantly to explaining the variation in exposure to Ae. aegypti bites: higher annual household income, younger age, larger lot area, and higher female Ae. aegypti abundance per trap night averaged over 5 weeks prior to human blood sampling. Conclusions: Most surveyed residents recognized mosquitoes and the threat they pose to individual and public health. Urbanistic (i.e., lot size), social (i.e., income within a low-income community and age), and entomological (i.e., adult female Ae. aegypti abundance) factors modulate the risk of human exposure to Ae. aegypti bites. The use of serological biomarker assays, such as the Bitemark Assay, are valuable tools for surveillance and risk assessment of mosquito-borne disease, especially in areas like the LRGV where the transmission of target pathogens is low or intermittent. Author summary: Aedes aegypti is a mosquito vector with public health importance on the global scale as it transmits viruses such as dengue, chikungunya, and Zika. Although transmission rates of dengue and Zika are low in the U.S., there are a few regions, including south Texas, where local transmission has occurred. Our study aimed to evaluate the factors associated with risk of exposure to these viruses using a serological bioassay that measured antibody response to an Ae. aegypti salivary protein to assess human-vector contact. We collected mosquitoes, took human-blood samples, and conducted urbanistic and demographic surveys in November 2021 in eight communities in the Lower Rio Grande Valley, Texas. Our knowledge, attitude, and practices survey found that most residents recognized adult mosquitoes, though few individuals knew someone personally who been sick with a mosquito-borne disease. Outdoor adult female Ae. aegypti abundance was positively associated with exposure to mosquito bites. Household income, individual age, and lot area also significantly affected exposure levels. The Bitemark Assay we used in this study can be utilized as a tool for entomological risk assessment and could be used as an alternative to infection exposure in areas where mosquito-borne disease levels are low. [ABSTRACT FROM AUTHOR]

Background: Mosquitoes in nature may acquire multiple bloodmeals (BMs) over the course of their lifetime; however, incorporation of frequent feeding behavior in laboratory vector competence studies is rarely done. We have previously shown that acquisition of a second non-infectious BM can enhance early dissemination of Zika virus (ZIKV), dengue virus, and chikungunya virus in Aedes aegypti and ZIKV in Aedes albopictus mosquitoes, yet it is unknown if other taxonomically-diverse virus-vector pairings show a similar trend under a sequential feeding regimen. Methods: To test this, we evaluated the impact of a second noninfectious BM on the vector competence of Aedes aegypti and Anopheles quadrimaculatus for Mayaro virus, Culex quinquefasciatus for West Nile virus, Aedes triseriatus for La Crosse virus, and Aedes aegypti for Oropouche virus (OROV). Female mosquitoes were fed BMs containing these viruses and half of them were given a second noninfectious BM at 3 or 4-days post infection. Mosquitoes were harvested at various time points and assayed for virus infection in bodies and disseminated infection in legs by performing reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assays. Results: We found that a second noninfectious BM had no impact on midgut infection rates but increased virus dissemination for all but one of the virus-vector pairings- Ae. aegypti and OROV. Unlike the other arboviruses under consideration, which are strictly mosquito-borne, biting midges (Culicoides spp.) serve as the main vector of OROV and this virus rarely disseminated to the mosquito leg tissue in our study. Conclusions: Taken together, our findings show that sequential blood feeding enhances virus dissemination across diverse arbovirus-vector pairings, representing three mosquito genera and virus families, but a second BM was insufficient to overcome a strong midgut virus escape barrier in a nonnatural virus–vector pairing. [ABSTRACT FROM AUTHOR]

Dengue fever, caused by dengue virus, poses a significant global health challenge, particularly in tropical regions where Aedes aegypti serves as the primary vector. The circadian clock in Aedes aegypti governs key behavioral and physiological processes, including activity patterns, feeding behaviors, and susceptibility to dengue virus infection. This article explores the influence of circadian rhythms on the mosquito's ability to transmit dengue virus, emphasizing how the circadian regulation of gene expression, immune responses, and lipid metabolism in the mosquito vector creates temporal windows that affect viral replication efficiency. [ABSTRACT FROM AUTHOR]

The spread of arboviruses like yellow fever, dengue, chikungunya, and Zika, transmitted by the invasive mosquito Aedes aegypti has led to the development of many strategies to suppress mosquito populations. Given the rapid development of resistance to common chemical larvicides and adulticides in some Ae. aegypti populations, as well as the ever-shrinking chemical options for mosquito control, there is a pressing need for new tools and deployment of those innovative tools as a component of integrative mosquito management programs. Prior to the adoption of any mosquito population intervention, be it conventional or innovative, understanding the baseline population is essential to evaluate the efficacy of the control measure. The Lee County Mosquito Control District in Florida has collected a three-year-long period of baseline entomological surveillance data collection for Ae. aegypti on Captiva and Sanibel Islands as foundational information prior to implementation of a new integrative mosquito management approach. We identified 18 mosquito species and described their population dynamics during the rainy and dry seasons. The two islands had no significant differences in species richness, diversity, dominance, or evenness overall. Yet, there were clear differences between the high rain season and low rain season in the Shannon diversity index, Simpson dominance index, and Pielou species evenness index within each site. Our data suggest that any innovative intervention should begin before mid to late April when the mosquito population is at its lowest and certainly before populations build up to their summer peak between June and September. These data also show the spatial distribution of Ae. aegypti is dynamic in space and time, identifying hotspots of mosquito abundance to focus on for future interventions. Overall, our study emphasizes the importance of entomological data collection to understand the population dynamics of Ae. aegypti mosquitoes, including the impact of environmental factors such as temperature and precipitation. [ABSTRACT FROM AUTHOR]

Background: Vector-borne diseases cause morbidity and mortality globally. However, some areas are more impacted than others, especially with climate change. Controlling vectors remains the primary means to prevent these diseases, but new, more effective tools are needed. The World Health Organization (WHO) prioritized evaluating novel control methods, such as sterile insect technique (SIT) for control of Aedes-borne diseases. In response, a multiagency partnership between the U.S. Centers for Disease Control and Prevention (CDC), the Special Programme for Research and Training in Tropical Diseases (TDR), WHO, and the International Atomic Energy Agency (IAEA) supported the operational implementation and evaluation of SIT against Aedes aegypti and arboviral diseases in the Pacific through a consortium of regional partners (PAC-SIT Consortium). Main text: A workshop was held from 2 to 6 May 2023, during which PAC-SIT country participants, researchers, and stakeholders in SIT, scientific advisory committee members, and organizational partners came together to review the principles and components of SIT, share experiences, visit field sites and the SIT facility, and officially launch the PAC-SIT project. Working in groups focused on entomology, epidemiology, and community engagement, participants addressed challenges, priorities, and needs for SIT implementation. Conclusions: The PAC-SIT workshop brought together researchers and stakeholders engaged in evaluating SIT for arboviral diseases in the Pacific region and globally. This training workshop highlighted that many countries are actively engaged in building operational capacities and phased testing of SIT. The workshop identified a key need for robust larger-scale studies tied with epidemiological endpoints to provide evidence for the scalability and impact on mosquito-borne diseases. [ABSTRACT FROM AUTHOR]

Background: Malaria prevention and control strategies have been hampered by urbanization and the spread of Anopheles stephensi. The spread of this vector into Africa further complicates the already complex malaria situation, that could put about 126 million Africans at risk of infection. Hence, this study aimed to assess the determinants of urban malaria, focusing on the role of urbanization and the distribution of An. stephensi in Eastern Ethiopia. Methods: A matched case control study was conducted among febrile urban residents of Dire Dawa (malaria positive as cases and negative as a control). A capillary blood sample was collected for parasite identification using microscopic examination and an interviewer administered questionnaire was used to collect additional data. Centers for Disease Control and Prevention miniature light traps (CDC-LT) and Prokopack aspirator were used to collect adult mosquito vectors from the selected cases and control houses to identify the mosquito vector species. Then, the data were exported to STATA for analysis. Conditional logistic regression was done to identify determinants, and principal component Analysis (PCA) was done for some independent variables. Results: This study enrolled 132 cases and 264 controls from urban setting only. Of the 132 cases, 90 cases were positive for Plasmodium falciparum, 34 were positive for Plasmodium vivax and 8 had mixed infections. All cases and controls were similar with regard to their respective age and sex. Travel history (AOR: 13.1, 95% CI 2.8–61.4), presence of eves and holes on walls (AOR: 2.84, 95% CI 1.5–5.5), history of malaria diagnosis (AOR: 2.4, 95% CI 1.1–5.3), owning any livestock (AOR: 7.5, 95% CI 2.4–22.8), presence of stagnant water in the area (AOR: 3.2, 95% CI 1.7–6.1), sleeping under bed net the previous night (AOR: 0.21, 95% CI 0.1–0.6) and knowledge on malaria and its prevention (AOR: 2.2, 95% CI 1.2–4.1) were determinants of urban malaria infection. About 34 adult Anopheles mosquitoes were collected and identified from those selected cases and control houses and 27 of them were identified as An. stephensi. Conclusion: Among the cases, the dominant species were P. falciparum. This study identified travel history, house condition, past infection, livestock ownership, stagnant water, bed net use, and malaria knowledge as determinants of infection. This study also found the dominance of the presence of An. stephensi among the collected mosquito vectors. This suggests that the spread of An. stephensi may be impacting malaria infection in the study area. Hence, strengthening urban-targeted malaria interventions should be enhanced to prevent and control further urban malaria infection and spread. [ABSTRACT FROM AUTHOR]

Background: Dengue is a serious public health problem worldwide, including Panama. During the last years, the number of dengue cases has increased. This may be due to the presence of mosquito populations resistant to insecticides. The aim of this study was to characterize the resistance status, its enzymatic mechanisms and Kdr mutations in wild populations of Aedes aegypti and Aedes albopictus. Methods: Standard WHO bioassays were performed using insecticide-treated filter papers to determine resistance in populations Ae. aegypti and Ae. albopictus to pyrethroids insecticides, organophosphates, to the carbamate propoxur and to the organochlorine DDT. Biochemical assays were conducted to detect metabolic resistance mechanisms and real-time PCR was performed to determine the frequencies of the Kdr mutations Val1016IIe and F1534C. Results: The strains Ae. aegypti El Coco showed confirmed resistance to deltamethrin (78.5% mortality) and lambda-cyhalothrin (81%), Aguadulce to deltamethrin (79.3%), David to deltamethrin (74.8%) and lambda-cyhalothrin (87.5%) and Puerto Armuelles to permethrin (83%). Aedes aegypti El Empalme showed confirmed resistance to pirimiphos-methyl (62.3% mortality), chlorpyrifos-methyl (55.5%) and propoxur (85.3%). All strains of Ae. albopictus showed possible resistance to PYs and five strains to DDT. Only Ae. albopictus Canto del Llano showed confirmed resistance to pirimiphos-methyl (70% mortality) and malathion (62%). Esterase activity was variable across sites with the most frequent expression of α-EST compared to β-EST in Ae. aegypti populations. In Ae. Albopictus, the expressed enzymes were β-EST and MFOs. Through ANOVA, significant differences were established in the levels of enzymatic activity of α- and β-EST, MFOs and GST, with p < 0.001 in the Ae. aegypti and Ae. albopictus. The Kdr Val1016IIe mutation was detected in Ae. aegypti Aguadulce, El Coco and David. The odds ratio for the Val1016Ile mutation ranged from 0.8 to 20.8 in resistant mosquitoes, indicating the association between pyrethroid phenotypic resistance and the kdr mutation. Conclusion: The presence of a varied and generalized resistance, enzymatic mechanisms and the Val1016IIe mutation may be associated with the intensive use and possibly misuse of the different insecticides applied to control Aedes populations. These results highlight the need to develop a program for resistance management. Also, alternative approaches to mosquito control that do not involve insecticides should be explored. [ABSTRACT FROM AUTHOR]

Background: Dengue fever is one of the most prevalent mosquito-borne diseases in Cambodia. Until now, no specific vaccine nor antiviral treatment exists the virus causing Dengue fever. Consequently, its prevention relies only on vector control strategies. However, efficient vector control in turn relies on a good knowledge of the biology of the vector species. Therefore, this study aims to provide the first review of the distribution, ecology, meteorological impacts, trophic behavior, vector competence, vector control and insecticide resistance of dengue vector species in Cambodia. Methods: A systematic search of the Google Scholar and PubMed databases was conducted for relevant published articles. Of the 610 published articles originally identified, 70 articles were ultimately selected for inclusion in this review. We also included new data from unpublished research conducted in Cambodia between 2017 and 2023 related to dengue vector bionomics. Results: Eleven Aedes (Stegomyia) mosquito species have been recorded in Cambodia, including a new species described in 2024. Four species are associated with dengue virus transmission, among which Aedes aegypti and Ae. albopictus are the main vectors and Ae. malayensis and Ae. scutellaris are considered to be potential vectors. Aedes aegypti and Ae. albopictus are present in all provinces of Cambodia. Aedes albopictus shows a preference for forest, rural and suburban areas, while Ae. aegypti is mostly found in urban and suburban areas. The distribution of these two species is also influenced by meteorological factors, seasonality and the availability of breeding habitats and blood meals. Both species are predominant during the rainy season, and their respective density is impacted by precipitation and temperature. Aedes aegypti is characterized as anthropophilic, while Ae. albopictus exhibits zooanthropophilic behavior, and both species have been observed to be predominantly diurnal. In addition, they were found to be highly resistant to the insecticides used in Cambodia for their control, such as temephos for larvae and deltamethrin and permethrin for adult mosquitoes. Conclusions: This review provides extensive and important knowledge on dengue vectors in Cambodia. This knowledge is derived not only from published research articles but also from many recent studies in Cambodia on the bionomics of dengue vector species. The review provides valuable information for use by public health authorities on dengue virus transmission and to develop better vector control strategies in the country. [ABSTRACT FROM AUTHOR]