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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.

Mosquitoes transmit viruses that affect public health in tropical regions. Identifying factors that influence their fitness can help control mosquito-borne diseases. We investigated the impacts of predation risk effects, from a fish predator, and food availability on the oviposition behavior of Aedes aegypti. We hypothesize that predation risk and food availability interactively affect Ae. aegypti oviposition. Gravid Ae. aegypti females were offered oviposition sites with all possible combinations of predation risk (with vs. without predator cues) and food availability (low vs. high). We found a significant interaction between predation risk and food availability. The magnitude of oviposition and the probability of egg laying in high food availability treatments exceeded the values of low food availability treatments, but only in treatments without predation risk. Predation risk critically modulated the effects of food availability on the oviposition of Ae. aegypti. This study demonstrates the interplay between predation risk and food availability in controlling mosquito-borne diseases. [ABSTRACT FROM AUTHOR]

Influxes of sargassos are responsible for economic and environmental disasters in areas where they bloom, especially in regions whose main income relies on tourism and with limited capacity for sanitation and public health response. A promising way of valorization would be to convert this incredible biomass into tools to fight the deadly vector mosquito Aedes aegypti. In the present study, we generated hydrolates and aqueous extracts from three main Sargassum morphotypes identified in Guadeloupe (French West Indies): Sargassum natans VIII, Sargassum natans I and Sargassum fluitans. We conducted a chemical characterization and a holistic evaluation of their potential to induce toxic and behavioral effects in Ae. aegypti. Despite the low insecticidal potential observed for all the extracts, we found that S. natans VIII and S. fluitans hydrolates deterred oviposition, induced contact irritancy and stimulated blood feeding behavior in host seeking Ae. aegypti females, while aqueous extracts from S. natans I and S. fluitans deterred both blood feeding behavior and oviposition. Chemical characterization evidenced the presence of phenylpropanoid, polyphenols, amino acids and esters. Thus, Sargassum spp. aqueous extracts and hydrolates could be used to manipulate Ae. aegypti behavior and be valorized as control tools against this mosquito. [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]

Background: C-type lectins (CTLs) are a large family of proteins with sugar-binding activity. CTLs contain an evolutionarily conserved C-type lectin domain (CTLD) that binds microbial carbohydrates in a calcium-dependent manner, thereby playing a key role in both microbial pathogenesis and innate immune responses. Aedes albopictus is an important vector for transmitting dengue virus (DENV) worldwide. Currently, the molecular characteristics and functions of CTLs in Ae. albopictus are largely unknown. Methods: Transcripts encoding CTL proteins in the Ae. albopictus genome assembly were analyzed via sequence blast. Phylogenetic analysis and molecular characterization were performed to identify the functional domains of the CTLs. Quantitative analysis was performed to determine the gene expression features of CTLs during mosquito development and in different tissues of female adults after blood feeding. In addition, the functional role of CTLs in response to DENV infection was investigated in Ae. albopictus mosquito cells. Results: We identified 39 transcripts encoding CTL proteins in the Ae. albopictus transcriptome. Aedes albopictus CTLs are classified into three groups based on the number of CTLDs and the domain architecture. These included 29 CTL-Ss (single-CTLDs), 1 immulectins (dual-CTLD) and 9 CTL-Xs (CTLDs with other domains). Phylogenetic analysis and structural modeling indicated that CTLs in Ae. albopictus are highly conserved with the homologous CTLs in Aedes aegypti. The expression profile assay revealed differential expression patterns of CTLs in both developmental stages and in adult female tissues. Knockdown and overexpression of three CTLs (CTL-S12, S17 and S19) confirmed that they can promote dengue virus infection in Ae. albopictus cells. Conclusions: The CTL genes in Ae. albopictus mosquito and other mosquito species are evolutionarily conserved and exhibit different developmental and tissue expression features. The functional assay indicated that three CTLs in Ae. albopictus mosquitoes are involved in promoting dengue virus infection. Our study revealed that CTLs play important roles in both the physiological processes and viral infection in mosquito vectors. [ABSTRACT FROM AUTHOR]

Background: This study conducted in the departments of Oueme and Plateau aims to assess the presence of the dengue virus and its different serotypes in Aedes aegypti and Aedes albopictus, as well as the epidemic risk incurred by the populations. Methods: Collections of adult mosquitoes using human landing catches (HLC) were carried out in six communes, three (Porto-Novo, Adjarra, and Avrankou) in the Oueme department and the rest (Ifangni, Kétou, and Pobè) in the Plateau department. Pools of ten Aedes mosquitoes were formed, and stored at −80°C in RNA later. RT-PCR was used to detect dengue virus, and conventional PCR for the different serotypes. Inspection of water containers and collection of Aedes larvae was performed inside and around each house to calculate the stegomyan indices. Results: In the six communes, the dengue virus was present both in Ae. aegypti and Ae. albopictus. Combined data of the two Aedes species at the communes level revealed infection rates ranging from 80.00% (95% CI: 61.43–92.29) to 96.67% (95% CI: 82.78–99.92). In all the communes, the values of stegomyan indices reached the WHO threshold, which indicates the existence of the risk of an arbovirus epidemic. In addition, the infection rates were similar for Ae. aegypti [88.19% (95% CI: 81.27–93.24)] and Ae. albopictus [86.79% (95% CI: 74.66–94.52)]. The three virus serotypes detected in the pools of Aedes were DENV-1, DENV-3, and DENV-4, with a high prevalence for the first two. Conclusion: This study revealed that three serotypes (DENV-1, DENV-3, and DENV-4) of dengue virus circulate in Ae. aegypti and Ae. albopictus in the departments of Oueme and Plateau. Moreover, the risk of transmission of arboviruses was globally high and variable from commune to commune. This information is essential for informed decision-making in the preventive control of the disease. [ABSTRACT FROM AUTHOR]

Background: Research on vector-borne diseases has traditionally centred on a limited number of vertebrate hosts and their associated pathogens, often neglecting the broader array of vectors within communities. Mosquitoes, with their vast species diversity, hold a central role in disease transmission, yet their capacity to transmit specific pathogens varies considerably among species. Quantitative modelling of mosquito-borne diseases is essential for understanding transmission dynamics and requires the necessity of incorporating the identity of vector species into these models. Consequently, understanding the role of different species of mosquitoes in modelling vector-borne diseases is crucial for comprehending pathogen amplification and spill-over into humans. This comprehensive overview highlights the importance of considering mosquito identity and emphasises the essential need for targeted research efforts to gain a complete understanding of vector-pathogen specificity. Methods: Leveraging the recently published book, 'Mosquitoes of the World', I identified 19 target mosquito species in Europe, highlighting the diverse transmission patterns exhibited by different vector species and the presence of 135 medically important pathogens. Results: The review delves into the complexities of vector-pathogen interactions, with a focus on specialist and generalist strategies. Furthermore, I discuss the importance of using appropriate diversity indices and the challenges associated with the identification of correct indices. Conclusions: Given that the diversity and relative abundance of key species within a community significantly impact disease risk, comprehending the implications of mosquito diversity in pathogen transmission at a fine scale is crucial for advancing the management and surveillance of mosquito-borne diseases. [ABSTRACT FROM AUTHOR]

• Essential oils from Cerrado plants are active against Aedes aegypti. • Alpinia zerumbet and E. langsdorffii oils show larvicide potential for Ae. aegypti. • Eugenia langsdorffii exhibits new larvicidal properties against mosquitos. The Aedes aegypti mosquito serves as the primary vector for transmitting viral diseases such as dengue, Zika, chikungunya, and urban yellow fever. Essential oils comprising volatile organic compounds derived from a single plant species have demonstrated repellent activity against various mosquito species, including Ae. aegypti. Despite their potential therapeutic benefits, only limited studies have explored the larvicidal activity of essential oil from plants occurring in Cerrado. To address this gap, the present study evaluated the larvicidal efficacy of different essential oils (EO) sourced from native and cultivated plants in the Cerrado biome against Ae. aegypti larvae. Essential oils were extracted from Alpinia zerumbet (Pers.) B.L.Burtt & R.M.Sm., Baccharis retusa DC., Blepharocalyx salicifolius (Kunth) O. Berg, Cymbopogon densiflorus (Steud.) Stapf , Eugenia langsdorffii O. Berg , Myracrodruon urundeuva Allemão. Notably, B. retusa is dioecious; hence, it was categorized into male and female plants each with a separated extraction of leaves and flowers. Among the essential oils tested, those derived from A. zerumbet and E. langsdorffii exhibited the highest activity, resulting in 100 % mortality of Ae. aegypti larvae at a 100 mg/L concentration. The calculated LC 50 values were 36.6 mg/L and 53.5 mg/L for A. zerumbet and E. langsdorffii, respectively, with the corresponding LC 90 values of 66.3 mg/L and 103.9 mg/L. Analysis of the major components revealed the presence of 1,8-cineole, sabinene, terpinen-4-ol, and γ-terpinene in A. zerumbet essential oil, while limonene, δ-cadinol, myrcene, and spathulenol were predominant in E. langsdorffii essential oil. However, further studies are required to identify the active components responsible for the observed larvicidal activity and elucidate their mode of action. [ABSTRACT FROM AUTHOR]

Insects geographically separated into island and mainland populations often exhibit phenotypic variations, a phenomenon known as insular conditions. These conditions can lead to rapid evolutionary changes that affect the morphological characteristics of mosquito vectors. Nevertheless, studies that specifically examine phenotype differences between island and mainland mosquito populations have been limited. In this study, wing variation in size and shape was investigated using the geometric morphometric (GM) technique in two dominant mosquito vectors, Aedes albopictus and Armigeres subalbatus, in the Ranong and Trat archipelagos of Thailand. Significant differences in average wing centroid size (CS) were found in 6 out of 15 population pairs for Ae. albopictus (p < 0.05) and in 5 population pairs for Ar. subalbatus (p < 0.05). After removing the allometric effect, canonical variate analyses (CVA) based on wing shape analysis revealed overlap across all populations for both Ae. albopictus and Ar. subalbatus. However, the statistical analysis indicated that Ar. subalbatus exhibited wing shape differences across all populations (p < 0.05), and most Ae. albopictus populations also displayed distinct wing shapes (p < 0.05), except for the populations from Chang Island and the mainland of Ranong, which showed no significant differences (p > 0.05). These findings enhance our understanding of mosquito adaptability in island regions and provide valuable data for the surveillance and monitoring of vector evolution. [ABSTRACT FROM AUTHOR]

Mosquito coil is commonly used in many African households for protection against mosquito bites. The coil usually has semi‐volatile pyrethroids as an active ingredient, which usually diffuse across open space, and the cloud either kills mosquitoes that are exposed, or mosquitoes can be exposed to sublethal doses of the insecticides. This study was conducted to assess the impact of sublethal doses of mosquito coil on the development of insecticide resistance in Aedes aegypti, a major vector for dengue fever and several other arboviral diseases. A laboratory colony of Ae. aegypti was exposed to sublethal doses of a meperfluthrin‐based mosquito coil in a Peet‐Grady chamber once per generation for 16 generations. The susceptibility of the exposed colony to a diagnostic dose of the mosquito coil as well as to three other insecticides was determined. Three different kdr mutations and five enzyme activities were evaluated in both the exposed and control colonies. After 16 generations of sublethal exposure to mosquito coils, the full diagnostic dose of the coil caused 68% mortality to the exposed colony compared to 100% mortality in the control colony. Mortality caused by deltamethrin (0.05%) was also significantly lower in the exposed colony. The frequency of 1016I kdr mutation as well as MFO and alpha esterase activities were higher in the exposed colony compared to the control colony. This study provides evidence of the development of pyrethroid resistance in an Ae. aegypti population due to sublethal exposure to mosquito coil for 16 generations. Given the large‐scale use of mosquito coils in many African households, its role as a pyrethroid resistance selection source should be taken into consideration when designing resistance management strategies. [ABSTRACT FROM AUTHOR]

Purpose : Aedes aegypti (L.,1762) is a primary vector of arboviral infections like dengue, yellow fever, Zika. Female mosquitoes are influenced by various physical and chemical cues from host when blood feeding, e.g., they find some individuals with certain blood types or certain conditions more attractive than others. This study determined whether Ae. aegypti shows a preference when offered blood from a patient with diabetes mellitus (DM), an endocrine disorder associated with abnormal glucose metabolism, compared to healthy blood from non-DMs. Methods: In the dual feeding experiments, forty newly emerged female mosquitoes were provided with two blood feeding systems with blood from a non-diabetic (healthy) and diabetic patient using artificial feeders. Blood from 12 diabetic and 12 non-diabetic patients was matched by ABO blood type (e.g., diabetic type O blood was compared with non-diabetic type O blood). The number of mosquitoes that landed and fed from each membrane was counted every 2 min for thirty minutes. Results: Ae. aegypti species significantly preferred for blood from non-diabetic individuals (50–65% among the different blood type groups) compared to blood from diabetic individuals. Using multiplex allele-specific PCR it was also determined that, Ae. aegypti significantly preferred the O blood group regardless of blood sugar level compared to others. Conclusion: Ae. aegypti has less preference for diabetic blood to non-diabetics. Regardless people affected with this condition need to take preventive measures to reduce mosquito bites as they tend to have weaker immune systems and can experience more severe cases of dengue. [ABSTRACT FROM AUTHOR]

BACKGROUND: Aedes aegypti is a widespread mosquito in tropical and subtropical regions that causes significant mortality and morbidity in humans by transmitting diseases, such as dengue fever and Zika virus disease. Synthetic insecticides, such as pyrethroids, have been used to control Ae. aegypti, but these insecticides can also affect nontarget organisms and contaminate soil and water. This study aimed to investigate the mosquitocidal activity of Pseudomonas mosselii isolated from pond sludge against larvae of Ae. aegypti. RESULTS: Based on the initial results, similar time‐course profiles were obtained for the mosquitocidal activity of the bacterial culture and its supernatant, and the pellet resuspended in Luria–Bertani (LB) medium also showed delayed toxicity. These results imply that the toxic component can be released into the medium from live bacteria. Further research indicated that the toxic component appeared in the supernatant approximately 4 h after a 3‐mL stock was cultured in 200 mL of LB medium. The stabilities of the P. mosselii culture and supernatant stored at different temperatures were also evaluated, and the best culture stability was obtained at 28 °C and supernatant stability at 4 °C. The bacterial culture and supernatant were toxic to larvae and pupae of not only susceptible Ae. aegypti but also pyrethroid‐resistant strains. CONCLUSION: This study highlights the value of the mosquitocidal activity of P. mosselii, which has potential as an alternative insecticide to control pyrethroid‐resistant Ae. aegypti in the field. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Mosquito host feeding patterns are an important factor of the species-specific vector capacity determining pathogen transmission routes. Culex pipiens s.s./Cx. torrentium are competent vectors of several arboviruses, such as West Nile virus and Usutu virus. However, studies on host feeding patterns rarely differentiate the morphologically indistinguishable females. Methods: We analyzed the host feeding attraction of Cx. pipiens and Cx. torrentium in host-choice studies for bird, mouse, and a human lure. In addition, we summarized published and unpublished data on host feeding patterns of field-collected specimens from Germany, Iran, and Moldova from 2012 to 2022, genetically identified as Cx. pipiens biotype pipiens, Cx. pipiens biotype molestus, Cx. pipiens hybrid biotype pipiens × molestus, and Cx. torrentium, and finally put the data in context with similar data found in a systematic literature search. Results: In the host-choice experiments, we did not find a significant attraction to bird, mouse, and human lure for Cx. pipiens pipiens and Cx. torrentium. Hosts of 992 field-collected specimens were identified for Germany, Iran, and Moldova, with the majority determined as Cx. pipiens pipiens, increasing the data available from studies known from the literature by two-thirds. All four Culex pipiens s.s./Cx. torrentium taxa had fed with significant proportions on birds, humans, and nonhuman mammals. Merged with the data from the literature from 23 different studies showing a high prevalence of blood meals from birds, more than 50% of the blood meals of Cx. pipiens s.s. were identified as birds, while up to 39% were human and nonhuman mammalian hosts. Culex torrentium fed half on birds and half on mammals. However, there were considerable geographical differences in the host feeding patterns. Conclusions: In the light of these results, the clear characterization of the Cx. pipiens s.s./Cx. torrentium taxa as ornithophilic/-phagic or mammalophilic/-phagic needs to be reconsidered. Given their broad host ranges, all four Culex taxa could potentially serve as enzootic and bridge vectors. [ABSTRACT FROM AUTHOR]

Aedes aegypti mosquitoes are major vectors of dengue, chikungunya, and other arboviral diseases. Ae. aegypti's capacity to reproduce and to spread disease depends on the female mosquitoes' ability to obtain blood meals and find water-filled containers in which to lay eggs (oviposit). While humidity sensation (hygrosensation) has been implicated in these behaviors, the specific hygrosensory pathways involved have been unclear. Here, we establish the distinct molecular requirements and anatomical locations of Ae. aegypti Dry Cells and Moist Cells and examine their contributions to behavior. We show that Dry Cell and Moist Cell responses to humidity involve different ionotropic receptor (IR) family sensory receptors, with dry air-activated Dry Cells reliant upon the IR Ir40α, and humid air-activated Moist Cells upon Ir68a. Both classes of hygrosensors innervate multiple antennal sensilla, including sensilla ampullacea near the antennal base as well as two classes of coeloconic sensilla near the tip. Dry Cells and Moist Cells each support behaviors linked to mosquito reproduction but contribute differently: Ir40α-dependent Dry Cells act in parallel with Ir68α-dependent Moist Cells to promote blood feeding, while oviposition site seeking is driven specifically by Ir68α-dependent Moist Cells. Together these findings reveal the importance of distinct hygrosensory pathways in blood feeding and oviposition site seeking and suggest Ir40α-dependent Dry Cells and Ir68α-dependent Moist Cells as potential targets for vector control strategies. [ABSTRACT FROM AUTHOR]

Background: Aedes aegypti, the primary vector of dengue, chikungunya, and Zika viruses, poses a significant public health threat worldwide. Traditional control methods using insecticides are increasingly challenged by resistance and environmental concerns. The sterile insect technique (SIT) offers an eco-friendly alternative that has been successfully applied to other insect pests. This article aims to briefly review Ae. aegypti management in Cuba, highlighting the accomplishments, challenges, and future directions of the SIT. Main body: Here we provide a brief summary of the extensive history of Ae. aegypti control efforts in Cuba. After a successful eradication campaign in the 1980s, a resurgence of dengue cases has been observed in recent years, suggesting that traditional control methods may have limited effectiveness under current conditions. In response, Cuba initiated a phased approach to develop and evaluate the feasibility of SIT for Ae. aegypti control, starting in 2008. Initial research focused on Ae. aegypti mating behavior and sterilization methods, followed by successful laboratory and semi-field trials that demonstrated population suppression. The first open-field trial in 2020 confirmed the efficacy of the SIT in reducing Ae. aegypti populations under real-world conditions. Currently, the research is in a phase involving a cluster-randomized superiority-controlled trial. This planned trial will compare the standard vector control program with the same program augmented by the SIT, aiming to assess the impact of the SIT on dengue incidence as the primary outcome. Implementing robust epidemiological trials to evaluate the effectiveness of the SIT is complex due to potential spillover effects from mosquito and human movement across study areas. Additionally, conducting the SIT requires significant development and operational investments. Despite these challenges, the ongoing Cuban trial holds promise for establishing the SIT as an effective and sustainable tool for Ae. aegypti control and for reducing the burden of mosquito-borne diseases. Conclusions: The phased evaluation conducted in Cuba confirms the efficacy of the SIT against Ae. aegypti, highlighting its potential for sustainable mosquito-borne disease management. The effective implementation of multi-site trials will be crucial in providing evidence of the potential of the sterile insect technique as part of a strategy to reduce the incidence of arboviral diseases. [ABSTRACT FROM AUTHOR]

The detection of insecticide resistance in male mosquitoes has been treated with less importance in monitoring insecticide resistance spread in mosquitoes. There are no studies on the susceptibility and synergistic activity of DDT and lambda-cyhalothrin on male Anopheles gambiae and Aedes aegypti in Delta State, Nigeria. Even though studies have extensively reported resistance in female mosquitoes, the susceptibility of male mosquitoes to insecticide classes should be ascertained. In this study, we tested the susceptibility status and synergistic activity of DDT and Lambda-cyhalothrin on An. gambiae and Ae. aegypti in Delta State, Nigeria, in order to ascertain the level of resistance and knockdown. In addition, we modelled the knockdown time using Probit analysis model. WHO bioassay method was used to expose two days old adult mosquitoes to 4% DDT and 0.05% lambda-cyhalothrin. The results showed that An. gambiae mosquitoes exposed to DDT and lambda-cyhalothrin were confirmed resistant (61% and 53% respectively). However, pre-exposing the resistant mosquito population to piperonyl butoxide (4%) showed an increase in mortality to 90% (possible resistance) in DDT and 98% (susceptible) in lambda-cyhalothrin. Ae. aegypti mosquitoes exposed to DDT were susceptible (98%) while those exposed to lambda-cyhalothrin were confirmed resistant (87%) and this increased to complete mortality (100%) in PBO+lambda-cyhalothrin population. Furthermore, the results showed that the knockdown time (KDT50 and KDT95) in An. gambiae exposed to DDT was 39.5–71.2 minutes and 124.5–146.4 minutes respectively, while that of lambda-cyhalothrin was 33.0–81.8 minutes and 64.0–124.4 minutes respectively. In Ae. aegypti, KDT50 and KDT95 was 23.9 and 61.7minutes for DDT exposure whereas it was 5.6–15.3 minutes and 36.1–72.3 minutes for lambda-cyhalothrin exposure. It can be concluded that male An. gambiae mosquitoes exposed to the insecticides were resistant and the causes may be linked to certain resistant genes in the mosquitoes. The chances of transferring resistance are possible in wild species and molecular-based studies on the resistant gene in male mosquitoes as well as the tendencies of transfer are required to establish this focus. [ABSTRACT FROM AUTHOR]

Japanese encephalitis virus (JEV) is a zoonotic mosquito-transmitted Flavivirus circulating in birds and pigs. In humans, JEV can cause severe viral encephalitis with high mortality. Considering that vector-free direct virus transmission was observed in experimentally infected pigs, JEV introduction into an immunologically naïve pig population could result in a series of direct transmissions disrupting the alternating host cycling between vertebrates and mosquitoes. To assess the potential consequences of such a realistic scenario, we passaged JEV ten times in pigs. This resulted in higher in vivo viral replication, increased shedding, and stronger innate immune responses in pigs. Nevertheless, the viral tissue tropism remained similar, and frequency of direct transmission was not enhanced. Next generation sequencing showed single nucleotide deviations in 10% of the genome during passaging. In total, 25 point mutations were selected to reach a frequency of at least 35% in one of the passages. From these, six mutations resulted in amino acid changes located in the precursor of membrane, the envelope, the non-structural 3 and the non-structural 5 proteins. In a competition experiment with two lines of passaging, the mutation M374L in the envelope protein and N275D in the non-structural protein 5 showed a fitness advantage in pigs. Altogether, the interruption of the alternating host cycle of JEV caused a prominent selection of viral quasispecies as well as selection of de novo mutations associated with fitness gains in pigs, albeit without enhancing direct transmission frequency. Author summary: Japanese encephalitis virus (JEV) represents a major health threat in parts of Asia and Oceania. Primary vertebrate hosts are birds and pigs, but human infection also occurs and can cause severe encephalitis with high mortality. Like other Flaviviruses transmitted by insect bites, JEV requires replication in alternating cycles between mosquitoes on one side and birds or pigs on the other side. However, we previously reported that direct transmissions between pigs in absence of mosquitos can occur. Considering the increased risks for such events after the spread of JEV to a new region with immunologically naïve pigs, the present study was performed to understand if and how a series of direct transmissions would promote JEV adaptations to pigs and change virus-host interactions. Pigs infected with JEV passaged ten times showed enhanced clinical symptoms and stronger antiviral immune response, but luckily no increase in direct transmission was observed. Nevertheless, genomic analysis demonstrated a complete change in dominant virus variants, as well as selection of six viral amino acid changes. This indicates that interruptions of the alternating lifestyle of JEV causes a strong evolutionary pressure, which through fitness adaptations can change the viral characteristics. [ABSTRACT FROM AUTHOR]

Background: Understanding the relationship between blood-feeding and mating is important in effectively managing the most well-adapted vector insect, Aedes aegypti (Linnaeus). Although extensive studies have investigated the behavioural aspects of Aedes such as blood-feeding, mating, and their relationship, several knowledge gaps still exist. Therefore, the present study was undertaken to determine the possibility of successful mating by unfed, engorged, and partially to fully gravid (up to 5 days after blood-feeding with fully developed eggs) female Ae. aegypti mosquitoes and production of viable eggs. Methods: Mating of sexually mature adult Aedes aegypti was allowed in three different ways. In control 1, the females were allowed to mate before taking blood meal, and in control 2, the females were not at all allowed to mate. In the experiment, the females were separated into six categories, viz. D-0 to D-5. In D-0, the females were allowed to mate immediately after the bloodmeal and, in D-1, the females were allowed to mate on the first day of blood feeding, likewise, the females of D-2, D-3, D-4 and D-5 were allowed to mate on 2nd, 3rd, 4th and 5th day of blood feeding. Ovitrap was uniformly kept on the 4th day of blood feeding for the cages D-0 to D-3 for 1 h and then removed and for the cages D-4, and D-5, the ovitrap was kept on 4th and 5th day of blood feeding for 1h immediately after mating. The total number of eggs and the total number of hatching were counted. In the subsequent days, the entire experiment was replicated two times with different cohorts of mosquitoes, and the mean value of three experiments was used to draw Excel bars with 5% error bars and also for the statistical analysis. Results: It was found that mating just before oviposition was sufficient to produce 1581 eggs (70% compared with control) and fertilize 1369 eggs (85% compared with total eggs laid), which is far higher than the 676 non-hatching (unfertilized) eggs (30%) laid by unmated females. Although mating is not essential for producing eggs, our study shows that even brief exposure to the semen and seminal fluids greatly enhances the oviposition and hatching efficiency, even if the mating occurs just before oviposition. However, those females mating before blood-feeding and those mating after blood-feeding produced 2266 and 2128 eggs, with hatching rates of 96.78% and 95.54%, respectively. Hence, the retention time of seminal fluid in the female seems to influence the number of eggs laid and the number of eggs hatched. Conclusions: In general, mating is possible in Ae. aegypti even minutes before oviposition and is sufficient to produce a greater number of viable eggs. [ABSTRACT FROM AUTHOR]

Mosquito-borne viral diseases such as dengue fever, chikungunya, and yellow fever have been documented in Ethiopia since the 1960s. However, the efficacy of public health insecticides against Aedes aegypti that transmits these viruses remains poorly understood in the country, particularly in the Afar Region. Thus, the aim of the study was to assess the susceptibility status of Ae. aegypti to deltamethrin, permethrin, alpha-cypermethrin, pirimiphos-methyl, bendiocarb, and propoxur insecticides. Larvae and pupae of Aedes species were collected from Awash Arba, Awash Sebat, and Werer towns of the Afar Region of Ethiopia during July-October 2022, brought to the Aklilu Lemma Institute of Pathobiology, insectary and reared to adults. Non-blood-fed, 3–5 days-old females Ae. aegypti were exposed to pyrethroid, carbamate, and organophosphate insecticide impregnated papers in tube test following the standard guidelines. Knockdown rates were noted at 10 minutes interval until one hour. The mortality in mosquitoes was recorded 24 hours after 60 minutes of exposure. The mortality rates of Ae. aegypti exposed to propoxur were 87% in all the study towns. Similarly, 88% mortality in Ae. aegypti was recorded when tested with bendiocarb in Awash Sebat and Awash Arba towns. Suspected resistance of Ae. aegypti (95% mortality) to alpha-cypermethrin was observed in Awash Arba town. However, Ae. aegypti collected from all the three sites was observed to be susceptible to deltamethrin, permethrin, and pirimiphos-methyl. Ae. aegypti was resistant to 0.1% bendiocarb and 0.1% propoxur and possibly resistant to 0.05% alpha-cypermethrin. On the other hand, it was susceptible to 0.05% deltamethrin, 0.75% permethrin, and 0.25% pirimiphos-methyl. Thus, vector control products with deltamethrin, permethrin, and pirimiphos-methyl can be used in the control of adult Ae. aegypti in the Afar Region of Ethiopia. However, further studies should be carried out to evaluate the susceptibility status of Ae. aegypti to alpha-cypermethrin in the Awash Arba area. [ABSTRACT FROM AUTHOR]

Resistance to insecticides is one of the great challenges that vector control programs must face. The constant use of pyrethroid-type insecticides worldwide has caused selection pressure in populations of the Aedes aegypti vector, which has promoted the emergence of resistant populations. The resistance mechanism to pyrethroid insecticides most studied to date is target-site mutations that desensitize the voltage-gated sodium channel (VGSC) of the insect to the action of pyrethroids. In the present study, susceptibility to the pyrethroid insecticides permethrin, lambda-cyhalothrin, and deltamethrin was evaluated in fourteen populations from the department of Córdoba, Colombia. The CDC bottle bioassay and WHO tube methods were used. Additionally, the frequencies of the F1534C, V1016I, and V410L mutations were determined, and the association of resistance with the tri-locus haplotypes was examined. The results varied between the two techniques used, with resistance to permethrin observed in thirteen of the fourteen populations, resistance to lambda-cyhalothrin in two populations, and susceptibility to deltamethrin in all the populations under study with the CDC method. In contrast, the WHO method showed resistance to the three insecticides evaluated in all populations. The frequencies of the mutated alleles ranged from 0.05–0.43 for 1016I, 0.94–1.0 for 1534C, and 0.01–0.59 for 410L. The triple homozygous mutant CIL haplotype was associated with resistance to all three pyrethroids evaluated with the WHO bioassay, while with the CDC bioassay, it was only associated with resistance to permethrin. This study highlights the importance of implementing systematic monitoring of kdr mutations, allowing resistance management strategies to be dynamically adjusted to achieve effective control of Aedes aegypti. [ABSTRACT FROM AUTHOR]

Background: Indoor residual spraying (IRS) is one of the most effective malaria control tools. However, its application has become limited to specific contexts due to the increased costs of IRS products and implementation programmes. Selective spraying—selective spray targeted to particular areas/surfaces of dwellings—has been proposed to maintain the malaria control and resistance-management benefits of IRS while decreasing the costs of the intervention. Methods: A literature search was conducted to find (1) studies that assessed the resting behaviour of Anopheles mosquitoes and (2) studies that evaluated the impact of selective spraying on entomological and malaria outcomes. Additional articles were identified through hand searches of all references cited in articles identified through the initial search. A cost model was developed from PMI VectorLink IRS country programmes, and comparative cost analysis reports to describe the overall cost benefits of selective IRS. Results: In some studies, there appeared to be a clear resting preference for certain Anopheles species in terms of the height at which they rested. However, for other species, and particularly the major African malaria vectors, a clear resting pattern was not detected. Furthermore, resting behaviour was not measured in a standardized way. For the selective spray studies that were assessed, there was a wide range of spray configurations, which complicates the comparison of methods. Many of these spray techniques were effective and resulted in reported 25–68% cost savings and reduced use of insecticide. The reported cost savings in the literature do not always consider all of the IRS implementation costs. Using the IRS cost model, these savings ranged from 17 to 29% for programs that targeted Anopheles spp. and 18–41% for programmes that targeted Aedes aegypti. Conclusions: Resting behaviour is generally measured in a simplistic way; noting the resting spot of mosquitoes in the morning. This is likely an oversimplification, and there is a need for better monitoring of resting mosquitoes. This may improve the target surface for selective spray techniques, which could reduce the cost of IRS while maintaining its effectiveness. Reporting of cost savings should be calculated considering the entire implementation costs, and a cost model was provided for future calculations. [ABSTRACT FROM AUTHOR]

The Dengue virus (DENV), primarily spread by Aedes aegypti and also by Aedes albopictus in some regions, poses significant global health risks. Alternative techniques are urgently needed because the current control mechanisms are insufficient to reduce the transmission of DENV. Introducing Wolbachia pipientis into Ae. aegypti inhibits DENV transmission, however, the underlying mechanisms are still poorly understood. Innate immune effector upregulation, the regulation of autophagy, and intracellular competition between Wolbachia and DENV for lipids are among the theories for the mechanism of inhibition. Furthermore, mainly three immune pathways Toll, IMD, and JAK/STAT are involved in the host for the suppression of the virus. These pathways are activated by Wolbachia and DENV in the host and are responsible for the upregulation and downregulation of many genes in mosquitoes, which ultimately reduces the titer of the DENV in the host. The functioning of these immune pathways depends upon the Wolbachia, host, and virus interaction. Here, we summarize the current understanding of DENV recognition by the Ae. aegypti's immune system, aiming to create a comprehensive picture of our knowledge. Additionally, we investigated how Wolbachia regulates the activation of multiple genes associated with immune priming for the reduction of DENV. [ABSTRACT FROM AUTHOR]

Background: Mosquito-borne diseases, such as malaria, dengue, Zika and chikungunya, pose significant public health threats in tropical and subtropical regions worldwide. To mitigate the impact of these diseases on human health, effective vector surveillance and control strategies are necessary. Traditional vector control methods, which rely on chemical agents such as insecticides and larvicides, face challenges such as resistance and environmental concerns. Consequently, there has been a push to explore novel surveillance and control tools. Mass trapping interventions have emerged as a promising and environmentally friendly approach to reducing the burden of mosquito-borne diseases. This study assessed mass-trapping interventions using autocidal gravid ovitraps (AGOs) on Aedes aegypti populations in Reynosa, Tamaulipas, Mexico. Methods: Four neighborhoods were selected to evaluate the effects of three treatments: AGO mass-trapping, integrated vector control (IVC), which included source reduction and the application of chemical larvicide and adulticide, and AGO + IVC on Ae. aegypti populations. A control area with no interventions was also included. The effectiveness of the interventions was evaluated by comparing Ae. aegypti abundance between the pre-treatment period (9 weeks) and the post-treatment period (11 weeks) for each treatment. Results: Only treatment using AGO mass trapping with an 84% coverage significantly reduced Ae. aegypti female populations by 47%, from 3.75 ± 0.32 to 1.96 ± 0.15 females/trap/week. As expected, the abundance of Ae. aegypti in the control area did not differ from the pre- and post-treatment period (range of 4.97 ± 0.59 to 5.78 ± 0.53); Ae. aegypti abundance in the IVC treatment was 3.47 ± 0.30 before and 4.13 ± 0.35 after, which was not significantly different. However, Ae. aegypti abundance in the AGO + IVC treatment increased from 1.43 ± 0.21 before to 2.11 ± 0.20 after interventions; this increase may be explained in part by the low AGO (56%) coverage. Conclusions: This is the first report to our knowledge on the effectiveness of mass-trapping interventions with AGOs in Mexico, establishing AGOs as a potential tool for controlling Ae. aegypti in Northeastern Mexico when deployed with sufficient coverage. [ABSTRACT FROM AUTHOR]

Treatment of livestock with endectocides such as ivermectin is viewed as a complementary vector control approach to address residual transmission of malaria. However, efficacy of this treatment may vary between animal species. Hence, our purpose was to investigate the effects of ivermectin treatments of common livestock species on life history traits of the opportunistic malaria vector Anopheles coluzzii. Sheep, goats and pigs were treated using injectable veterinary ivermectin formulation at the species-specific doses (recommended dose for all species and high dose in pig). Mosquito batches were exposed to treated and control (not injected) animals at different days after treatment. Daily mosquito mortality was recorded and fecundity assessed through the count of gravid females and the number of eggs they developed. The recommended dose of ivermectin induced a significant decrease in mosquito survival for up to 7 days after injection (DAI), with a decrease of 89.7%, 66.7%, and 48.4% in treated pigs, goats and sheep, respectively, compared to control animals. In treated pigs, the triple therapeutic dose decreased mosquito survival of 68.97% relatively to controls up to 14 DAI. The average number in gravid females Anopheles that survived after feeding on treated animals were reduced when blood-meals were taken on sheep (2.57% and 42.03% at 2 and 7 DAI), or on goats (decrease of the 28.28% and 73.64% respectively at 2 and 7 DAI). This study shows that ivermectin treatments to animals negatively impacts An. coluzzii life history traits and could reduce vector densities in areas where livestock live near humans. However, due to short-term efficacy of single dose treatments, repeated treatments and potentially increased dosages would be required to span the transmission season. The use of long-acting ivermectin formulations is discussed as a mean for extending efficacy while remaining cost effective. [ABSTRACT FROM AUTHOR]

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

Aedes aegypti is an important vector of dengue virus and other arboviruses that affect human health. After being ingested in an infectious bloodmeal, but before being transmitted from mosquito to human, dengue virus must disseminate from the vector midgut into the hemocoel and then the salivary glands. This process, the extrinsic incubation period, typically takes 6–14 days. Since older mosquitoes are responsible for transmission, understanding the age structure of vector populations is important. Transcriptional profiling can facilitate predictions of the age structures of mosquito populations, critical for estimating their potential for pathogen transmission. In this study, we utilized a two-gene transcript model to assess the age structure and daily survival rates of three populations (Key West, Marathon, and Key Largo) of Ae. aegypti from the Florida Keys, United States, where repeated outbreaks of autochthonous dengue transmission have recently occurred. We found that Key Largo had the youngest Ae. aegypti population with the lowest daily survival rate, while Key West had the oldest population and highest survival rate. Across sites, 22.67% of Ae. aegypti females were likely old enough to transmit dengue virus (at least 15 days post emergence). Computed estimates of the daily survival rate (0.8364 using loglinear and 0.8660 using non-linear regression), indicate that dengue vectors in the region experienced relatively low daily mortality. Collectively, our data suggest that Ae. aegypti populations across the Florida Keys harbor large numbers of older individuals, which likely contributes to the high risk of dengue transmission in the area. Author summary: Within a mosquito population it is generally only the very old mosquitoes that are capable of spreading disease-causing pathogens, like dengue virus. Scientists have been developing fast, accurate, and cheap methods to estimate mosquito age. In this study, we used one of those methods to measure the activity of age-responsive genes in dengue virus-transmitting Aedes aegypti mosquitoes from the Florida Keys, a dengue hotspot in the United States. This method allowed us to estimate the percentage of older mosquitoes in this region. We found that a high percentage of Ae. aegypti mosquitoes in Key Largo, Marathon, and Key West (between 11–32%) were likely old enough to be able to spread dengue virus. We also observed that Ae. aegypti from the Florida Keys experienced relatively low daily mortality, as the daily probability of survival for any given mosquito was estimated at 86–88%. These findings suggest that conditions in the Florida Keys are very suitable for mosquitoes to thrive, reach old age, and potentially contribute to dengue outbreaks in the region. [ABSTRACT FROM AUTHOR]

Background: Aedes aegypti (L.) is the main vector of dengue, yellow fever, Zika, and chikungunya viruses in many parts of the world, impacting millions of people worldwide each year. Insecticide-based interventions have been effective in controlling Aedes mosquito populations for several years, but in recent times, resistance to these compounds has developed, posing a global threat to the control of this mosquito. Methods: Ovitraps were used to collect A. aegypti eggs in the cities of Tartagal and San Ramón de la Nueva Orán (Salta), Puerto Iguazú (Misiones), and Clorinda (Formosa). World Health Organization (WHO)-impregnated papers with the discriminating concentration (DC) of permethrin, 5X, 10X and pirimiphos methyl were used for the toxicological bioassays. We also genotyped each sample for the three kdr single nucleotide polymorphisms (SNP): V410L, V1016I, and F1534C in individual TaqMan quantitative PCR (qPCR) reactions. Results: All investigated A. aegypti populations were highly resistant to permethrin, as the mortality percentage with the permethrin 10×DC remained below 98%. However, all populations were 100% susceptible to pirimiphos-methyl. Kdr genotyping demonstrated the presence of the V410L mutation for the first time in Argentina in all the populations studied. A prevalence of the triple mutant genotype (LL + II + CC) was observed in the northeastern cities of Clorinda (83.3%) and Puerto Iguazú (55.6%). Conclusions: This study demonstrates for the first time the presence and intensity of resistance to permethrin in different populations from Argentina, and correlates the observed phenotype with the presence of kdr mutations (genotype). [ABSTRACT FROM AUTHOR]

Background: Wolbachia symbiosis in Aedes aegypti is an emerging biocontrol measure against dengue. However, assessing its real-world efficacy is challenging due to the non-randomised, field-based nature of most intervention studies. This research re-evaluates the spatial–temporal impact of Wolbachia interventions on dengue incidence using a large battery of quasi-experimental methods and assesses each method's validity. Methods: A systematic search for Wolbachia intervention data was conducted via PUBMED. Efficacy was reassessed using commonly-used quasi-experimental approaches with extensive robustness checks, including geospatial placebo tests and a simulation study. Intervention efficacies across multiple study sites were computed using high-resolution aggregations to examine heterogeneities across sites and study periods. We further designed a stochastic simulation framework to assess the methods' ability to estimate intervention efficacies (IE). Results: Wolbachia interventions in Singapore, Malaysia, and Brazil significantly decreased dengue incidence, with reductions ranging from 48.17% to 69.19%. IEs varied with location and duration. Malaysia showed increasing efficacy over time, while Brazil exhibited initial success with subsequent decline, hinting at operational challenges. Singapore's strategy was highly effective despite partial saturation. Simulations identified Synthetic Control Methods (SCM) and its variant, count Synthetic Control Method (cSCM), as superior in precision, with the smallest percentage errors in efficacy estimation. These methods also demonstrated robustness in placebo tests. Conclusions: Wolbachia interventions exhibit consistent protective effects against dengue. SCM and cSCM provided the most precise and robust estimates of IEs, validated across simulated and real-world settings. [ABSTRACT FROM AUTHOR]

Mosquitoes such as Aedes aegypti must consume a blood meal for the nutrients necessary for egg production. Several transcriptome and proteome changes occur post‐blood meal that likely corresponds with codon usage alterations. Transfer RNA (tRNA) is the adapter molecule that reads messenger RNA codons to add the appropriate amino acid during protein synthesis. Chemical modifications to tRNA enhance codon decoding, improving the accuracy and efficiency of protein synthesis. Here, we examined tRNA modifications and transcripts associated with the blood meal and subsequent periods of vitellogenesis in A. aegypti. More specifically, we assessed tRNA transcript abundance and modification levels in the fat body at critical times post blood‐feeding. Based on a combination of alternative codon usage and identification of particular modifications, we discovered that increased transcription of tyrosine tRNAs is likely critical during the synthesis of egg yolk proteins in the fat body following a blood meal. Altogether, changes in both the abundance and modification of tRNA are essential factors in the process of vitellogenin production after blood‐feeding in mosquitoes. [ABSTRACT FROM AUTHOR]

The tiny bloodsucker Aedes aegypti is the primary vector of some fatal diseases like dengue, zika and yellow fever which presents a significant concern for the healthcare sector of Bangladesh. To manage this insect vector, the feasibility of Sterile Insect Technique (SIT) in Bangladesh is being investigated for which quality radio-sterilized males are indispensable. Typically, the sterile males are chilled at low temperature to facilitate their transportation from rear-out-facility to the release site, concurrently to minimize the metabolism, stress and physical damage. In this study, the impact of chilling temperatures (4, 7 and 10 °C) and exposure periods (1, 4, 8 and 24 h) have been studied on the survival, chill-coma recovery rate (CCRR), induced sterility and flight ability of lab-reared local A. aegypti strain. Different chilling temperatures had insignificant effect on CCRR except the 24 h exposure duration. Log-rank test of Kaplan-Meier survival curve showed the significant effect of chilling temperature and duration on the survival. Notably, the chilling temperature of 7 °C exposed for 1 h was found to be optimum in terms of survival. Hence, the induced sterility and flight ability were studied only for this specific temperature and duration, revealing the insignificant effects between the sterile-chilled and sterile but non-chilled A. aegypti. This study underscores the recommendation to chill the mosquitoes at 7 °C for 1 h which will be helpful for the implementation of SIT in Bangladesh. [ABSTRACT FROM AUTHOR]

Mosquitoes, particularly Aedes aegypti, are of paramount importance in scientific research due to their critical epidemiological significance in transmitting dangerous diseases. Their ability to thrive amidst complex environmental conditions is largely attributed to their symbiotic relationships with microorganisms. In this comprehensive study, we explored the intricate bacterial communities within the gut of fourth instar Ae. aegypti larvae sourced from the underexplored Kole wetlands. Our investigation employed a blend of culture-dependent and culture-independent techniques, revealing a diverse array of bacteria, notably Bacillaceae and Enterobacteriaceae. Notably, Rahnella was found to be a consistent gut inhabitant across seasons and locales. Metagenomic analysis uncovered the presence of various phyla, with Firmicutes dominating during monsoon and post-monsoon seasons, while Proteobacteria prevailed in the pre-monsoon season. These findings lay a strong foundation for future research into the intricacies of host-microbiota interactions and their implications in mosquito-related diseases, offering insights into public health concerns. [ABSTRACT FROM AUTHOR]

Dengue fever disease is an important health issue in the city of Jeddah, Saudi Arabia. Chemical pesticides play a vital role in dengue control, through combating the mosquito vector Aedes aegypti L. Standard methods recommended by the World Health Organization were applied in the current work to conduct resistance experiments in both adult and larval stages of Ae. aegypti mosquitoes against eight types of pyrethroid and organophosphorus pesticides used in control programs in Jeddah. The results prove that Ae. aegypti is resistant against the pesticides deltamethrin 0.05%, α‐cypermethrin 0.05%, fenitrothion 1% and temephos, is tolerant with some degree of resistance against cyfluthrin 0.15% and λ‐cyhalothrin 0.5%, as well as tolerant against malathion 5% and pirimiphos‐methyl 0.25%. On the other hand, the bacterial insecticide Bacillus thuringiensis ssp. israelensis (Bti) demonstrated high activity against the field strain of Aedes aegypti larvae, with a resistance ratio (RR) of 1.25. In general, we conclude from these findings that the continuous and frequent application of synthetic pesticides induces resistance in mosquitoes against pesticides. This, of course, forces us to reconsider the pesticides currently used in control programs and do our best towards finding alternative means to combat mosquitoes and the diseases that they can transmit. [ABSTRACT FROM AUTHOR]

Recent reports have disclosed the occurrence of Wolbachia in Aedes aegypti. Our study detected Wolbachia infection in Ae. aegypti by screening wild adult mosquitoes using two Wolbachia‐specific molecular markers. Overall, 444 adult Ae. aegypti mosquitoes were collected from April 2022 to October 2022 in Jeddah, Saudi Arabia. Each individual sample was processed and screened for the presence of Wolbachia using selected markers, the Wolbachia‐specific 16S rDNA and the Wolbachia surface protein gene (wsp), under optimized polymerase chain reaction (PCR) conditions, and sequenced. In total, 39 (8.78%) and 48 (10.81%) individual mosquito samples were determined to be infected with Wolbachia using the wsp and 16S rDNA markers, respectively. By utilizing two Wolbachia‐specific molecular markers, our study demonstrated the presence of Wolbachia from individual Ae. aegypti samples. Our results showed a low rate of Wolbachia infection and inferred that the detected strain belongs to supergroup B. [ABSTRACT FROM AUTHOR]

This study investigated the in vivo efficacy of a chromium derivative extracted from date palms pit against Aedes aegypti the third instar larvae, the known vector of dengue fever in Saudi Arabia. Chromone 1, a flavonoid chromone component, was isolated from the alcoholic extract of date palm pits (DPP) using High‐performance liquid chromatography (HPLC). The results showed that exposure of A. aegypti larvae to whole DPP extract and chromone 1 for 24 h resulted in significant insecticidal efficacy with LC50 values of 132.82 and 54.64 ppm, respectively. The same concentrations also effectively inhibited AChE (acetylcholinesterase) activity up to −56.83 and −58.58%, respectively, compared to controls. The acetylcholine bromide test further confirmed the interaction between chromone 1 and AChE. The results also revealed that the chromone 1 treatment altered Deoxyribonucleic Acid (DNA) and protein content. It also exhibited that the extract of date palm pits DPP can effectively serve as sustainable ingredients for the control management of A. aegypti. [ABSTRACT FROM AUTHOR]

Culex tarsalis Coquillett (Diptera: Culicidae) mosquitoes are capable of vectoring numerous pathogens affecting public and animal health. Unfortunately, the probing behaviors of mosquitoes are poorly understood because they occur in opaque tissues. Electropenetrography (EPG) has the potential to elucidate these behaviors by recording the electrical signals generated during probing. We used an AC–DC EPG with variable input resistors (Ri levels) to construct a waveform library for Cx. tarsalis feeding on human hands. Biological events associated with mosquito probing were used to characterize waveforms at four Ri levels and with two electrical current types. The optimal settings for EPG recordings of Cx. tarsalis probing on human hands was an Ri level of 107 Ohms using an applied signal of 150 millivolts alternating current. Waveforms for Cx. tarsalis included those previously observed and associated with probing behaviors in Aedes aegypti L. (Diptera: Culicidae): waveform families J (surface salivation), K (stylet penetration through the skin), L (types 1 and 2, search for a blood vessel/ingestion site), M (types 1 and 2, ingestion), N (type 1, an unknown behavior which may be a resting and digestion phase), and W (withdrawal). However, we also observed variations in the waveforms not described in Ae. aegypti, which we named types L3, M3, M4, and N2. This investigation enhances our understanding of mosquito probing behaviors. It also provides a new tool for the automated calculation of peak frequency. This work will facilitate future pathogen acquisition and transmission studies and help identify new pest and disease management targets. [ABSTRACT FROM AUTHOR]

Wolbachia symbionts introduced into Aedes mosquitoes provide a highly effective dengue virus transmission control strategy, increasingly utilised in many countries in an attempt to reduce disease burden. Whilst highly effective against dengue and other positive-sense RNA viruses, it remains unclear how effective Wolbachia is against negative-sense RNA viruses. Therefore, the effect of Wolbachia on Bunyamwera virus (BUNV) infection in Aedes aegypti was investigated using wMel and wAlbB, two strains currently used in Wolbachia releases for dengue control, as well as wAu, a strain that typically persists at a high density and is an extremely efficient blocker of positive-sense viruses. Wolbachia was found to reduce BUNV infection in vitro but not in vivo. Instead, BUNV caused significant impacts on density of all three Wolbachia strains following infection of Ae. aegypti mosquitoes. The ability of Wolbachia to successfully persist within the mosquito and block virus transmission is partially dependent on its intracellular density. However, reduction in Wolbachia density was not observed in offspring of infected mothers. This could be due in part to a lack of transovarial transmission of BUNV observed. The results highlight the importance of understanding the complex interactions between multiple arboviruses, mosquitoes and Wolbachia in natural environments, the impact this can have on maintaining protection against diseases, and the necessity for monitoring Wolbachia prevalence at release sites. [ABSTRACT FROM AUTHOR]

The most prevalent arthropod-borne viruses, including the dengue viruses, are primarily transmitted by infected mosquitoes. However, the dynamics of dengue virus (DENV) infection and dissemination in human skin following Aedes aegypti probing remain poorly understood. We exposed human skin explants to adult female Ae. aegypti mosquitoes following their infection with DENV-2 by intrathoracic injection. Skin explants inoculated with a similar quantity of DENV-2 by a bifurcated needle were used as controls. Quantitative in situ imaging revealed that DENV replication was greatest in keratinocytes in the base of the epidermis, accounting for 50–60% of all infected cells regardless of the route of inoculation. However, DENV inoculation by Ae. aegypti probing resulted in an earlier and increased viral replication in the dermis, infecting twice as many cells at 24 h when compared to needle inoculation. Within the dermis, enhanced replication of DENV by Ae. aegypti infected mosquitoes was mediated by increased local recruitment of skin-resident macrophages, dermal dendritic cells, and epidermal Langerhans cells relative to needle inoculation. An enhanced but less pronounced influx of resident myeloid cells to the site of mosquito probing was also observed in the absence of infection. Ae. aegypti probing also increased recruitment and infection of dermal mast cells. Our findings reveal for the first time that keratinocytes are the primary targets of DENV infection following Ae. aegypti inoculation, even though most of the virus is inoculated into the dermis during probing. The data also show that mosquito probing promotes the local recruitment and infection of skin-resident myeloid cells in the absence of an intact vasculature, indicating that influx of blood-derived neutrophils is not an essential requirement for DENV spread within and out of skin. [ABSTRACT FROM AUTHOR]

Background: To assess whether the 'economic boom' in the tropical seaport city of Barranquilla improved tapped water supplies to socio-economically poor neighbourhoods resulting in: (1) their reduced use for domestic water-storage in large (> 1,000-litre) custom-made cement tanks which are their principal Aedes aegypti breeding sites and (2) their pupae/person index (PPI) values to below their established 0.5–1.5 PPI arbovirus transmission-threshold value, compared to matched neighbourhoods in the: (a) pre-economic boom (2004) period in Barranquilla and (b) economically-neglected seaport city of Buenaventura. Methods: The simple, accurate and robust water surface sweep-net/calibration factor or total count methods were used to determine the total Ae. aegypti pupae numbers in greater or less than 20-litre water-holding container types located 'inside' or 'outside' these neighbourhood premises. The women residents also participated in questionnaire-based responses about their domestic water supplies, water-storage and maintenance and mosquito life stages and disease transmission knowledge, to subsequently plan appropriate resident education programmes. Microsoft Excel 8.0 with OpenEpi was used to determine the samples sizes and the statistical values. Results: Tapped water supplies to the three poor Barranquilla neighbourhoods were dramatically increased from 2004 to 2023 resulting in their residents significantly reducing their: (a) large cement water-storage tanks from 1 per 6.9 (2004) to 1 per 31.2 (2020) premises (z = 10.5: p = 0) and (b) PPI values to 0.16, 0.19 and 0.53 (mean: 0.29: 95% CI ± 0.4) in each study neighbourhood. In contrast, tapped water supplies remained inadequate in the Buenaventura neighborhoods, thereby resulting in their continued use of many large (> 1,000-litre) water-storage containers (Barranquilla: 1 per 31.2 and Buenaventura: 1 per 1.5 premises: z = − 9.26: p = 0), with unacceptably high 0.81, 0.88 and 0.99 PPI values in each study neighbourhood (mean 0.89: 95% CI ± 0.12). Conclusions: Improved tapped water supplies resulted in reduced numbers of large custom-made stoneware water-containers, as are employed by poor residents throughout the world, as well as their Ae. aegypti PPI transmission threshold values which, together with appropriate residents' education programmes, are also urgently to reduce to prevent/reduce Ae. aegypti transmitted human diseases globally. [ABSTRACT FROM AUTHOR]

The synthesis of nanoparticles utilizing green techniques is becoming increasingly important due to its low cost, biocompatibility, high productivity, and eco-friendliness. Herein, the current work focused on the biosynthesis, characterization, and biological applications of zinc oxide nanoparticles (ZnO-NPs) from Anabasis articulata, including antioxidant anticancer and larvicidal properties, as well as modifications to the phytochemical ingredients. Hence, the tannin, phenolic, and flavonoid concentrations of the produced nanoparticle samples were lower than those of the original aqueous extract. When compared to the results of ascorbic acid (12.78 mg/mL), the produced extract of A. articulata and its zinc nanoparticles showed remarkable efficacy as antioxidant agents with IC50 values of 27.48 and 69.53 mg/mL, respectively. A normal lung fibroblast cell line (WI-38) and three tumor cells were used to test the compounds' anticancer properties. With an IC50 of 21.19 µg/mL, the ZnO-NPs of A. articulata showed the greatest cytotoxicity against HePG-2 cell lines. Additionally, A. articulata zinc nanoparticles showed significant cytotoxicity against MCF-7 and PC3 tumor cell lines, with IC50 values of 30.91 and 49.32 µg/mL. The biogenic ZnO-NPs had LC50 and LC90 values of 13.64 and 26.23 mg/L, respectively, and are very effective against Aedes aegypti larval instar (III). Additionally, the percentages of larval mortality increased from 28.61% at 5 ppm to 84.69% at 25 ppm after 24 h post-treatment. The overall results of this study point to the potential of A. articulata as a substitute biological agent for potential therapeutic/leutic uses in the medical domains and for preventing the proliferation of malarial vector insects. [ABSTRACT FROM AUTHOR]

Aedes mosquito-borne diseases remain a significant global health threat, necessitating effective control strategies. This study introduces monoterpenes-based nanohydrogels for potential use as repellents against Aedes aegypti, the primary dengue vector worldwide. We formulated hydrogels using cymene- and myrcene-based nanoemulsions with different polymers: chitosan, carboxymethylcellulose (CMC), and carbopol®. Our evaluations of rheological, texture, and bioadhesive properties identified CMC hydrogel as the most promising gelling agent for topical application, exhibiting sustained monoterpene release over 12 h with low skin permeation and high retention in the stratum corneum. Myrcene-loaded CMC hydrogel achieved a 57% feeding deterrence compared to 47% with cymene hydrogel in the mosquito membrane-feeding model. Molecular docking studies revealed interactions between myrcene and an essential amino acid (Ile116) in the Ae. aegypti odorant-binding protein 22 (AeOBP22), corroborating its higher repellent efficacy. These findings suggest that myrcene-loaded CMC hydrogels offer a promising, minimally invasive strategy for personal protection against Ae. aegypti and warrant further investigation to optimize monoterpene concentrations for vector control. [ABSTRACT FROM AUTHOR]

Symbiotic and pathogenic microorganisms such as bacteria and fungi represent promising alternatives to chemical insecticides to respond to the rapid increase of insecticide resistance and vector‐borne disease outbreaks. This study investigated the interaction of two strains of Wolbachia, wAlbB and wAu, with the natural entomopathogenic fungi from Burkina Faso Metarhizium pingshaense, known to be lethal against Anopheles mosquitoes. In addition to showing the potential of Metarhizium against African Aedes aegypti wild‐type populations, our study shows that the wAlbB and wAu provide a protective advantage against entomopathogenic fungal infections. Compared to controls, fungal‐infected wAu and wAlbB‐carrying mosquitoes showed higher longevity, without any significant impact on fecundity and fertility phenotypes. This study provides new insights into the complex multipartite interaction among the mosquito host, the Wolbachia endosymbiont and the entomopathogenic fungus that might be employed to control mosquito populations. Future research should investigate the fitness costs of Wolbachia, as well as its spread and prevalence within mosquito populations. Additionally, evaluating the impact of Wolbachia on interventions involving Metarhizium pingshaense through laboratory and semi‐field population studies will provide valuable insights into the effectiveness of this combined approach. [ABSTRACT FROM AUTHOR]

Simple Summary: This study emphasizes the significance of appropriate air-drying times in toxicity bioassays to accurately establish sublethal concentrations and discriminating concentrations for resistance detection in mosquitoes to a highly volatile pyrethroid, namely, transfluthrin. The high-throughput screening system toxicity bioassay study demonstrated consistent dose-dependent responses in susceptible mosquito populations. Our findings emphasize the importance of accurate susceptibility testing to facilitate early resistance detection. The air-drying duration significantly affected the efficacy of transfluthrin: after drying for 24 h, the concentration needed to achieve the same level of efficacy was 2.8 times higher compared to the concentration needed after 1 h of drying. This is the first study to evaluate spatial repellents using a high-throughput screening system toxicity bioassay, yielding precise sublethal concentrations and discriminating concentrations for varying air-drying times of transfluthrin-treated filter papers. The study underscores the importance of early detection of resistant mosquito populations and emphasizes the need to optimize air-drying durations in toxicity bioassays. Selecting the right concentrations and assessing behavioral responses are crucial for developing effective mosquito control strategies with spatial repellents. This research enhances our understanding of resistance dynamics and provides guidance for practical implementation in vector control programs. Increasing temperature can enhance the geographical spread and behavior of disease vector mosquitoes, exposing vulnerable populations to Aedes-borne viruses and infections. To address this risk, cost-effective and sustained intervention vector control tools are required, such as volatile pyrethroid spatial repellents. This study used a high-throughput screening system toxicity bioassay to determine the discriminating concentrations of transfluthrin-treated filter papers with variable air-drying times exposed to pyrethroid-susceptible Aedes aegypti mosquitoes. At the highest transfluthrin concentration (0.01706%), a significant reduction in mosquito mortality was observed in filter papers air-dried for 24 h compared to those air-dried for 1 h (odds ratio = 0.390, p < 0.001, 95% confidence interval: 0.23–0.66). Conversely, no significant difference in mortality was found between filter papers air-dried for 1 h and those air-dried for 12 h (odds ratio = 0.646, p = 0.107, 95% confidence interval: 0.38–1.10). The discriminating concentration was 2.8-fold higher for transfluthrin-treated filter papers air-dried for 24 h than it was for papers air-dried for 1 h, and it increased 5-fold from 1 h to 336 h of air-drying. These results show that the optimal air-drying period of transfluthrin-treated filter paper is critical, as higher discriminating concentration values may lead to underestimations of insecticide resistance. The instability of transfluthrin-treated papers necessitates the use of the World Health Organization (WHO) bottle bioassay, which is the preferred method for determining mosquito susceptibility to volatile insecticides. [ABSTRACT FROM AUTHOR]

Simple Summary: The main mosquito species capable of transmitting arboviruses belong to the genera Aedes spp., Psorophora spp., Anopheles spp., Culex spp., Mansonia spp., Coquillettidia spp., Haemagogus spp., Sabethes spp., Culiseta spp., and Wyeomyia spp. Some neglected mosquito species have the potential to become significant disease vectors due to parameters such as global distribution, rapid adaptation to urban areas, and anthropophilic habits. This review discusses the epidemiological importance and biology of three neglected mosquitoes, Aedes scapularis, Aedes vittatus, and Aedes japonicus japonicus, in the context of vectorial capacity and how urbanization, climate change, and globalization alter disease transmission dynamics and may increase the participation of neglected species in propagating diseases. More than 3550 species of mosquitoes are known worldwide, and only a fraction is involved in the transmission of arboviruses. Mosquitoes in sylvatic and semi-sylvatic habitats may rapidly adapt to urban parks and metropolitan environments, increasing human contact. Many of these mosquitoes have been found naturally infected with arboviruses from the Alphaviridae, Flaviviridae, and Bunyaviridae families, with many being the cause of medically important diseases. However, there is a gap in knowledge about the vector status of newly invasive species and their potential threat to human and domestic animal populations. Due to their rapid distribution, adaptation to urban environments, and anthropophilic habits, some neglected mosquito species may deserve more attention regarding their role as secondary vectors. Taking these factors into account, we focus here on Aedes (Ochlerotatus) scapularis (Rondani), Aedes japonicus japonicus (Theobald), and Aedes (Fredwardsius) vittatus (Bigot) as species that have the potential to become important disease vectors. We further discuss the importance of these neglected mosquitoes and how factors such as urbanization, climate change, and globalization profoundly alter the dynamics of disease transmission and may increase the participation of neglected species in propagating diseases. [ABSTRACT FROM AUTHOR]

Simple Summary: Over the last decade, optical sensors have demonstrated great potential to provide complementary data to monitor insect abundance. This article introduces a field-deployable and non-destructive optical instrument to monitor the abundance of flying insects, called an Entomological Bistatic Optical Sensor System, or eBoss. The study focuses on comparing abundance measurements made by the eBoss and physical traps over an 8-month field campaign. The eBoss made over 302,000 insect observations and evaluated the aerial density (#/m3) of all flying insects as well as specifically male and female mosquitoes with a 1 min resolution, allowing us to monitor both the abundance over the season and daily peak of activity. The study's objectives were to validate the optical sensor's data against physical trap collections, which confirmed the correlation between the two methods. However, the eBoss demonstrated superior temporal resolution (1 min versus approximately 3 days) and statistical power due to its larger sample size. These findings suggest that an eBoss can significantly enhance flying insect monitoring efforts, such as mosquitoes or pollinators, providing valuable insights for vector control strategies, agriculture and public health planning. Optical sensors have shown significant promise in offering additional data to track insect populations. This article presents a comparative study between abundance measurements obtained from a novel near-infrared optical sensor and physical traps. The optical instrument, named an Entomological Bistatic Optical Sensor System, or eBoss, is a non-destructive sensor operating in the near-infrared spectral range and designed to continuously monitor the population of flying insects. The research compares the mosquito aerial density (#/m3) obtained through the eBoss with trap counts from eight physical traps during an eight-month field study. The eBoss recorded over 302,000 insect sightings and assessed the aerial density of all airborne insects as well as male and female mosquitoes specifically with a resolution of one minute. This capability allows for monitoring population trends throughout the season as well as daily activity peaks. The results affirmed the correlation between the two methods. While optical instruments do not match traps in terms of taxonomic accuracy, the eBoss offered greater temporal resolution (one minute versus roughly three days) and statistical significance owing to its much larger sample size. These outcomes further indicate that entomological optical sensors can provide valuable complementary data to more common methods to monitor flying insect populations, such as mosquitoes or pollinators. [ABSTRACT FROM AUTHOR]

Simple Summary: Mosquito surveys conducted in the Democratic Republic of Sao Tome and Principe during 2000 to 2016 as a part of anti-malaria programs found the presence of four species of mosquitoes in the nation including Culex (Culex) poicilipes, Mansonia (Coquillettidia) annetti, Uranotaenia (Uranotaenia) alboabdominalis, and Uranotaenia (Uranotaenia) fraseri for the first time. Aedes albopictus (Skuse, 1894) was identified in 2015, and the follow-up survey confirmed that Aedes albopictus has become widespread across the nation. The larvae were predominant in artificial water-holding containers, with a positive rate up to 45.6% in used tires in Príncipe, while the native species, Aedes aegypti, preferred natural breeding sources. Phylogenetic analysis based on mitochondrial DNA revealed the introduced populations belonged to a clade involved in the worldwide spread of the species. Aedes albopictus is a public health threat due to its vectorial capacity for various arboviruses. Continuous vector surveillance and implication of interventions, such as source reduction to remove used tires, environmental management, and use of larvicides, were suggested. Aedes albopictus (Skuse, 1894), a mosquito originating in Asia, has been introduced to Africa since the 2000s. The mosquito is not only a nuisance but is capable of transmitting various arboviruses. The current study summarized our entomological surveys in the Democratic Republic of Sao Tome and Principe during 2000 to 2016. Adult mosquitoes were collected by sweep nets, human landing catches, and Centers for Disease Control (CDC) light traps, and the immatures were collected from water-filled habitats at 15 sentinel sites and reared to adulthood. Species identification was performed based on morphologic characteristics. Fragments of the cytochrome C oxidase subunit I (COI) and the Wolbachia surface protein (wsp) genes were amplified for mosquitoes collected in Principe. New records of four mosquito species were reported. Aedes albopictus was identified in 2015. The larvae were found distributed over the nation and were predominately in artificial water-holding containers (488/2698, 18.1%). The highest positive rate was observed in used tires in Príncipe (114/250, 45.6%). Mitochondrial DNA analysis revealed low genetic diversity among the invasive populations, but all tested specimens were superinfected by Wolbachia. The ability of Ae. albopictus to adapt to new environments and its involvement in disease transmission make the surveillance and control of this species particularly important. [ABSTRACT FROM AUTHOR]

Background: Describing spatio-temporal occurrence and habitat characteristics of Aedes mosquito larvae is crucial for the control of Aedes borne viral diseases. This study assessed spatio-temporal abundance and habitat characteristics of Aedes larvae in the Southern Afar Region, Ethiopia. Methods: Immature mosquitoes were surveyed in Awash Sebat, Awash Arba, and Werer towns of the Southern Afar Region once per month from May 2022 to April 2023. Larvae and pupae surveys were carried out along the available water-holding containers. The collected larvae/pupae were reared to adults and identified by species/genus morphologically. The physical and chemical properties of the habitats were also characterized. Results: A total of 9099 Aedes larvae/pupae were collected, of which 53.6% (4875) were from Awash Sebat, 29.5% (2687) from Awash Arba and 16.9% (1537) from Werer. Water-holding tyres harboured the highest number of Aedes larvae/pupae followed by water-storage drums. All the Aedes larvae/pupae reared to adults were morphologically identified as Aedes aegypti. The overall Container Index was 47.28%, House Index 18.19%, Breteau Index 59.94% and Pupal Index 171.94. Significant positive relations were observed in the occurrences of Ae. aegypti larvae/pupae with water-holding tyre (AOR = 15.89, CI = 3.55–71.09, p < 0.001), water storage drums (AOR = 19.84, CI = 4.64–84.89, p < 0.001), domestic habitat (AOR = 3.76, CI = 1.27–11.12, p = 0.017), and significant negative relations were observed with Ae. aegypti larvae/pupae occurrence and tap water source (AOR = 0.08, CI = 0.02–0.31, p = 0.001). Ae. aegypti larvae/pupae densities showed positive relations with dissolved oxygen (β = 0.523, p < 0.001) and total hardness (β = 0.475, p = 0.034) of water. Conclusions: Diverse types of artificial water-holding containers were positive for Ae. aegypti larvae/pupae. Ae. aegypti larvae/pupae were abundant in used water-holding tyres, water storage drums, and cement tanks in Awash Sebat, Awash Arba, and Werer towns. This could put the residents of the towns at high risk of infections with Ae. aegypti transmitted viral diseases such as chikungunya and dengue outbreaks. Thus, we recommend artificial water-holding container management as a strategy to control Ae. aegypti and hence the arboviral diseases transmission. [ABSTRACT FROM AUTHOR]

Multiple Wolbachia strains can block pathogen infection, replication and/or transmission in Aedes aegypti mosquitoes under both laboratory and field conditions. However, Wolbachia effects on pathogens can be highly variable across systems and the factors governing this variability are not well understood. It is increasingly clear that the mosquito host is not a passive player in which Wolbachia governs pathogen transmission phenotypes; rather, the genetics of the host can significantly modulate Wolbachia‐mediated pathogen blocking. Specifically, previous work linked variation in Wolbachia pathogen blocking to polymorphisms in the mosquito alpha‐mannosidase‐2 (αMan2) gene. Here we use CRISPR‐Cas9 mutagenesis to functionally test this association. We developed αMan2 knockouts and examined effects on both Wolbachia and virus levels, using dengue virus (DENV; Flaviviridae) and Mayaro virus (MAYV; Togaviridae). Wolbachia titres were significantly elevated in αMan2 knockout (KO) mosquitoes, but there were complex interactions with virus infection and replication. In Wolbachia‐uninfected mosquitoes, the αMan2 KO mutation was associated with decreased DENV titres, but in a Wolbachia‐infected background, the αMan2 KO mutation significantly increased virus titres. In contrast, the αMan2 KO mutation significantly increased MAYV replication in Wolbachia‐uninfected mosquitoes and did not affect Wolbachia‐mediated virus blocking. These results demonstrate that αMan2 modulates arbovirus infection in A. aegypti mosquitoes in a pathogen‐ and Wolbachia‐specific manner, and that Wolbachia‐mediated pathogen blocking is a complex phenotype dependent on the mosquito host genotype and the pathogen. These results have a significant impact for the design and use of Wolbachia‐based strategies to control vector‐borne pathogens. [ABSTRACT FROM AUTHOR]