Search Results (222)

Dengue is the most concerning mosquito-borne neglected tropical disease globally. The disease is caused by the dengue virus (DENV) and transmitted by the vector mosquito species belonging to the genus Aedes Meigen, 1818, particularly Aedes aegypti (Linnaeus, 1762) and Aedes albopictus (Skuse, 1895). In 2024, global cases of dengue exceeded 7.6 million, with India reporting 233,519 cases. These statistics underscore the ongoing challenge of managing dengue outbreaks worldwide. For generations, tribal communities across India have employed medicinal plant-based extracts as mosquito and other insect repellents. Plant-based phytochemicals are largely preferred over synthetic insecticides due to their perceived safety, non-toxicity to non-target organisms, and environmental sustainability. This review provides a comprehensive overview of various phytochemicals extracted from Indian medicinal plants for their larvicidal activity against Aedes mosquitoes. Furthermore, the article also reviews the mode of action of these phytochemicals, including neurotoxicity, mitochondrial dysfunction, sterol carrier protein-2 inhibition, midgut cytotoxicity, insect growth regulation disruption, and antifeedant activity, which aids in formulating dengue vector control strategies. Based on this review, Ecbolin B from Ecbolium viride, Alizarin from Rubia cordifolia, and Azadirachtin from Azadirachta indica exhibited better larval mortality rates against Ae. aegypti, with LC50 values recorded at 0.70, 1.31, and 1.7 ppm, respectively. Full article

Mosquito-borne diseases, including dengue fever, chikungunya, and Zika, continue to pose a substantial global public health challenge. This is largely attributable to the absence of effective vaccines and the expanding distribution of vectors such as Aedes albopictus (Ae. albopictus). Repellents, therefore, remain a critical component of prevention strategies for disease prevention. However, existing formulations have notable limitations. Synthetic repellents such as DEET provide broad-spectrum efficacy but may raise safety concerns, especially at high concentrations. In contrast, botanical repellents, such as citronella and camphor oils, offer more favorable safety profiles but are restricted by short protection durations due to their high volatility. To overcome these drawbacks, this research developed a composite mosquito repellent through the strategic combination of DEET (5–15%), citronella oil (10–20%), and camphor oil (5–15%). This formulation leverages interactions across multiple olfactory pathways to simultaneously enhance efficacy and reduce the DEET concentration. Orthogonal experimental optimization identified an optimized formulation, Mix-3 (consisting of 15% DEET, 15% citronella oil, and 10% camphor oil in 75% ethanol), which achieved a mean complete protection time of 9.45 h. Mix-3 provided longer protection than 7% DEET (mean difference = 5.50 h, p < 0.001), 4.5% IR3535 (2.83 h, p < 0.001), 10% citronella oil (3.58 h, p < 0.001), and 15% DEET (6.50 h, p < 0.001). Catnip oil did not contribute significantly to repellency (p = 0.895). This study demonstrates that the rational combination of synthetic and botanical repellents effectively overcomes the limitations of single-agent formulations, providing a long-lasting and scalable approach for vector control. Full article

Arthropod-borne viruses (arboviruses) such as dengue, chikungunya, Zika, and yellow fever pose significant global health risks, with mosquitoes from the Aedes genus as the primary vectors responsible for human transmission. The Republic of the Marshall Islands (RMI), particularly the urbanized areas of Kwajalein and Majuro atolls, has experienced multiple outbreaks of dengue, Zika, and chikungunya with substantial health and economic impacts. Vector control remains the most effective method for reducing disease risk, but comprehensive data on local mosquito vector composition, distribution, and abundance are needed to guide new, effective control efforts. From 2022 to 2024, we conducted a longitudinal baseline assessment of mosquito abundance and species composition on Ebeye and nearby islets in Kwajalein Atoll, RMI, using BG-Sentinel traps and ovitraps. Aedes aegypti was the most prevalent species, accounting for 58% of all adult females collected across study locations, with higher relative abundances on Ebeye than on northern islets (4.7 vs. 2.3 per trap/night). Aedes albopictus was more abundant on northern islets (0.7 vs. 3.2 per trap/night), and Culex quinquefasciatus showed similar abundances (1.2 vs. 1.7 per trap/night). Rainfall and anthropogenic factors, including water storage practices and housing density, influenced mosquito abundance. These findings provide multi-seasonal baseline data to support targeted vector control strategies in RMI. Full article

Dengue is a mosquito-borne viral disease transmitted by Aedes aegypti, the main vector in the Americas. The lack of effective antiviral treatments, limited vaccine coverage, and the increasing resistance of mosquitoes to conventional insecticides emphasize the need for alternative vector control strategies. Plant-derived larvicides represent a promising and eco-friendly approach. This study characterized the phytochemical profile of Persea americana Mill. (var. Lorena) and evaluated its larvicidal activity against Ae. aegypti (Rockefeller strain). The phytochemical profile was assessed through qualitative screening, UV-Vis spectrophotometry, and UHPLC analysis. Larvicidal activity was evaluated against third-instar larvae of Ae. aegypti (Rockefeller strain) and the median lethal concentration (LC₅₀) values were determined. Preliminary screening of ethanolic extracts revealed the presence of various secondary metabolites of pharmacological relevance, including alkaloids, coumarins, tannins, flavonoids, saponins, triterpenes/sterols, and quinones. UV-Vis spectra displayed distinct absorption patterns, with a prominent peak near 260 nm, consistent with the presence of aromatic compounds. UHPLC profiling revealed high chemical diversity across different plant parts, with 70, 98, 71, and 52 peaks (above 1 × 10⁵ intensity) detected in seed, flower, pulp, and leaf extracts, respectively. Larvicidal bioassays showed significant activity, particularly in the seed extract, with LC₅₀ values (µg/mL) of 3.8 (3.3–4.1) for seeds, 22.4 (21.8–23.9) for flowers, 23.0 (21.5–24.6) for pulp, and 29.7 (28.1–31.2) for leaves. This study highlights the larvicidal potential of ethanolic extracts from P. americana (var. Lorena), with the seed extract exhibiting the highest chemical diversity and bioactivity against Ae. aegypti larvae. The detection of key secondary metabolites, including flavonoids, alkaloids, and saponins, supports the development of an effective, plant-based larvicide for sustainable vector control strategies. Full article

Dengue (DENV), Chikungunya (CHIKV), and Zika (ZIKV) are emerging arboviral threats in Bangladesh, transmitted by Aedes mosquitoes thriving in urban Dhaka. Overlapping symptoms complicate diagnosis, and Bangladesh-specific data on arboviral antibody reactivity are limited. In four hospitals of Dhaka, we conducted a cross-sectional study on 438 febrile patients aged ≥10 years, collecting samples between September and December 2023 to describe arboviral antibody reactivity and their distribution across selected demographic and environmental characteristics. Rapid diagnostic tests (RDTs) for DENV and CHIKV were performed, followed by enzyme-linked immunosorbent assay (ELISA) on RDT-reactive samples. Participants had a mean age of 30 years (±13.5); two-thirds were male, and most lived in crowded, low-income households. RDTs indicated DENV/CHIKV antibody reactivity in 40% of participants; 170 samples underwent ELISA, suggesting DENV IgG reactivity in 33.5% and IgM reactivity in 15.5%. CHIKV IgG reactivity (0.7%) was low and ZIKV IgG was reactive in 21% of total samples, and IgM was reactive in one (0.2%); most ZIKV IgG-reactive samples also showed DENV IgG reactivity, suggesting cross-reactivity. DENV IgG and IgM reactivity were associated with lower education, while ZIKV IgM reactivity was associated with older age. Awareness of Aedes mosquitoes was low, and environmental risk factors were common. This study provides cross-sectional data on serological reactivity against DENV, CHIKV, and ZIKV among febrile patients attending four hospitals of Dhaka, without aiming to establish etiologic causes of illness. ZIKV IgG antibody reactivity requires confirmatory testing to distinguish true infections from other arboviral cross-reactivity. Strengthened community-based surveys, better public awareness, and sustained vector control are critical for reducing arboviral disease risks in urbanizing settings like Dhaka, Bangladesh. Full article

La Crosse virus (LACV) is a mosquito-borne virus (family Peribunyaviridae) that can result in severe human infection in children under sixteen. Historically, LACV comprised two lineages, predominantly in the Midwest and Appalachian regions of the US. In 2005, a virus of a third lineage was detected in the Northeast; however, this and subsequently isolated strains of lineage III have not, to date, been implicated in human disease. One hypothesis for this discrepancy is that vector mosquitoes have a reduced vector competency for LACV lineage III, thus preventing horizontal transmission and clinical cases. Here, we utilized two mosquito species, Aedes triseriatus, the native vector, and Aedes albopictus, an invasive potential vector, each from both a historic LACV range (Virginia) and from the region of lineage III (Connecticut). Utilizing oral feeding and intrathoracic inoculation methods of viral exposure, rates of LACV infection, dissemination, and transmission (proxied via salivary secretion) and capability for vertical transmission (proxied via virus-positive ovaries) were determined by harvesting mosquito bodies, legs, saliva, and ovaries, respectively. Overall, we did not detect consistent differences in transmission between any lineage, species, or state of origin, at day 14 post-infection. However, we highlight the transmission potential of LACV lineage III in all mosquito populations tested here, representing the first evidence of lineage III competency in Aedes triseriatus and Aedes albopictus, indicating the potential for human disease. We thus suggest that the absence of human cases of LACV lineage III is not modulated by a lack of vector competency in mosquitoes. Full article

In Brazil, public health programs have relied predominantly on chemical insecticides to control Aedes aegypti, Anopheles spp., Culex quinquefasciatus, triatomines, and phlebotomines. Rising vector-borne disease incidence and insecticide resistance (IR) call for a critical appraisal of historical and current control practices. This literature review compiles secondary data produced from 1901 to 2024 obtained from Medline/PubMed, Google Scholar, and governmental notes and reports. Brazil’s vector control progressed from organochlorines (e.g., DDT) to organophosphates, carbamates, pyrethroids, insect growth regulators, microbial larvicides (Bti and Lsp), spinosad, and recently formulations with dual active-ingredient. Ae. aegypti showed widespread resistance to temephos and pyrethroids, decreased susceptibility to pyriproxyfen, and no documented Bti resistance. Anopheles spp. exhibited low to moderate resistance to pyrethroids. Cx. quinquefasciatus resistance is likely influenced by collateral exposure from Aedes control and domestic use. Regarding triatomines and phlebotomines, there was a predominant reliance on pyrethroids; most studies indicate their susceptibility to these compounds. In short, Brazil’s century-long, insecticide-centric strategy has delivered episodic gains but fostered Aedes aegypti resistance. For other species, for which there is no dedicated program for a long period, data on resistance are scarce or nonexistent. Sustainable progress requires strengthened, nationwide IR surveillance and entomological mapping to coordinate cross-program actions. Full article

Background/Objectives: As of April 2025, La Réunion is facing a second major chikungunya virus (CHIKV) outbreak, following the 2005–2006 epidemic that infected nearly one-third of the population. IXCHIQ^®, a live-attenuated, single-dose vaccine, offers an opportunity for targeted immunization to complement vector control efforts. Using surveillance data up to 23 February 2025 (week 7), we estimated the potential scale of the 2024–2025 chikungunya outbreak in La Réunion and how much of the burden could have been averted by an emergency vaccination campaign at different detection thresholds. Methods: A stochastic SEIR–SEI host–vector model was calibrated to weekly case counts (weeks 46/2024–7/2025). We projected the epidemic under three vaccination-trigger scenarios (≥100, ≥3000, ≥40,000 detected cases) and two incremental vector-control assumptions (10% and 20% reductions in biting rate). Several mosquito-related parameters—extrinsic incubation period, offspring number, and mortality rate—were temperature-dependent, based on daily temperatures in La Réunion. Vaccination was applied homogeneously, using a 14.5% coverage to reflect the proportion of the population targeted in the initial public health recommendation. Results: Our findings indicate that without vaccination, up to 27.5% of the population could become infected. If vaccination would begin after 100 detected cases, 75% of infections could be prevented. Delaying until 3000 or 40,000 cases reduced effectiveness to 41% and 11%, respectively. Conclusions: Our results show that timely emergency vaccination can substantially reduce outbreak size. This underscores the importance of preparedness and rapid response by public health authorities in high-risk regions. Full article

Background and Objectives: Climate change is modifying the ecological and climatic conditions that influence the distribution and activity of arthropod vectors. Rising temperatures and prolonged warm seasons have favored the establishment of Aedes albopictus in Mediterranean regions, increasing the risk of autochthonous Dengue transmission. Therefore, this study describes the evolution of Dengue surveillance in Sardinia between 2018 and 2024, integrating human and entomological data to assess trends, system performance, and implications for prevention and control. Materials and Methods: Data on human cases were retrieved from national notification systems (namely PREMAL, arbo.iss.it) and the New Health Information System. Entomological surveillance data were obtained from the Experimental Zooprophylactic Institute of Sardinia. Mosquitoes were collected using BG-Sentinel^® traps and ovitraps, covering major cities and points of entry. Descriptive analyses were conducted for both datasets. Results: Sixteen Dengue cases were reported during the study period, all imported and laboratory-confirmed in 81% of cases. Most patients were adults (mean age 38 years), and 77% required hospitalization. The most frequent travel origins were Southeast Asia, Africa, and Latin America. No autochthonous cases were identified. Entomological surveillance showed a progressive increase in Aedes albopictus captures from 2020 onwards, with seasonal peaks between September and October. Despite intensified sampling and expanded geographic coverage, no mosquito pools tested positive for the Dengue virus. Conclusions: Although no locally acquired Dengue infections have been detected, the widespread and increasing presence of Aedes albopictus indicates that Sardinia meets the ecological prerequisites for possible autochthonous transmission. Strengthening the timeliness and completeness of human surveillance, improving clinicians’ awareness of reporting requirements, promoting vaccination for travelers, and maintaining continuous entomological monitoring are essential to prevent and promptly manage future outbreaks. Full article

Alphavirus chikungunya (CHIKV) is an arthropod-borne alphavirus of the Togaviridae family, transmitted primarily by Aedes aegypti and Ae. albopictus mosquitoes. CHIKV infection often results in debilitating manifestations that compromise quality of life and generate significant socioeconomic impacts. Recurrent epidemics in tropical and subtropical regions underscore the urgent need to better understand the host immune responses and their contribution to disease outcome. CHIKV establishes infection by overcoming the host’s initial immunological barriers. Innate immune cells, including fibroblasts, dendritic cells, macrophages, monocytes, neutrophils and natural killer (NK) cells, are among the first to respond to infection, ensuring a rapid antiviral defense and supporting the development of adaptive immune responses. However, excessive release of inflammatory mediators and prolonged infiltration of innate cells into joint tissues contribute to disease chronicity and the persistence of arthralgia. In this review, we provide a comprehensive synthesis of current evidence on innate cells that serve as targets for CHIKV infection, highlighting mechanisms that promote effective antiviral defense as well as those responsible for pathological inflammation and chronic disease and identifying key gaps that remain to be addressed. Full article

Dengue fever, a mosquito-borne viral disease, has become a significant global health concern in recent decades, particularly in Iran. This integrative review provides a comprehensive assessment of the epidemiological trends of dengue fever in Iran from its initial emergence to the present, identifying and evaluating factors contributing to both the emergence and re-emergence of the disease at national and international levels. The review highlights critical global determinants influencing dengue transmission, including climate change, environmental modifications, unplanned urbanization, increased international travel and trade, and the pivotal roles of public awareness and healthcare infrastructure. Climatic variables, such as rising temperatures and altered precipitation patterns, create favorable conditions for mosquito breeding, enabling vectors like Aedes aegypti and Aedes albopictus to expand into new regions. We also explore how environmental changes, unplanned urbanization and other factors further exacerbate the situation. Control strategies addressing these factors are presented. In Iran, the incidence of dengue fever is increasing, yet research remains limited. The highest number of local cases has been reported in Chabahar and Bandar Lengeh, Hormozgan and Sistan and Baluchestan Provinces, respectively. Eleven key factors—culminating in socio-cultural practices, climate change, unplanned urbanization, cross-border mobility, and gaps in vector control and healthcare infrastructure—have been identified as contributing to recent outbreaks in Iran. In conclusion, our review underscores that mitigating dengue vulnerability in Iran requires an urgent, multi-faceted strategy targeting improved urban water management, enhanced cross-border surveillance, and strengthened healthcare system capacity. Full article

Oviposition attractants can enhance both the surveillance and control of container-breeding Aedes mosquitoes. Although green tea has been reported to attract Ae. aegypti, the specific bioactive botanical compounds responsible remain unidentified. We evaluated teas across fermentation stages (non-fermented, fully fermented, and post-fermented) at 5 g/L for gravid Ae. albopictus using dual-choice assays. The most attractive tea (Liu-pao) was further tested across concentrations (0.5–5 g/L) and infusion ages (1–28 days). Autoclaved vs. non-autoclaved infusions assessed microbial contributions, while headspace volatiles were analyzed via HS-SPME-GC-MS. Individual compounds (cedrol and linalool oxide) were bioassayed. Only Liu-pao tea consistently attracted Ae. albopictus (OAI ≥ 0.3), peaking at 5 g/L after 7–14 days (OAIs 0.73/0.67). A 0.5 g/L infusion aged 21–28 days also attracted Ae. aegypti (OAIs 0.89/0.63). Autoclaving did not reduce attraction, confirming volatile compounds, not live microbe-mediated effects. Cedrol (1 mg/L) elicited moderate attraction (OAI 0.29) in Ae. albopictus, while linalool oxide was inactive. Post-fermented Liu-pao tea acts as a potent botanical attractant for Aedes mosquitoes. Cedrol contributes partially, but whole tea infusions outperform single compounds. These findings support developing multi-volatile “attract-and-kill” strategies targeting gravid mosquitoes. Full article

In Ecuador, the transmission of dengue has steadily increased in recent decades, particularly in coastal cities like Manta, where the conditions are favorable for the proliferation of the Aedes aegypti mosquito. The objective of this study was to model the spatial distribution of dengue transmission risk in Manta, a coastal city in Ecuador with consistently high incidence rates. A total of 148 georeferenced dengue cases from 2018 to 2021 were collected, and environmental and socioeconomic variables were incorporated into a maximum entropy model (MaxEnt). Additionally, climate and social zoning were performed using a multi-criteria model in TerrSet. The MaxEnt model demonstrated excellent predictive ability (training AUC = 0.916; test AUC = 0.876) and identified population density, sewer system access, and distance to rivers as the primary predictors. Three high-risk clusters were identified in the southern, northwestern, and northeastern parts of the city, while the coastal strip showed lower suitability due to low rainfall and vegetation. These findings reveal the strong spatial heterogeneity of dengue risk at the neighborhood level and provide operational information for targeted interventions. This approach can support more efficient surveillance, resource allocation, and community action in coastal urban areas affected by vector-borne diseases. Full article

Background: The global health burden of mosquito-borne viruses, including dengue, yellow fever, Zika, and chikungunya, is rising due to climate change and globalisation, which favour mosquito habitat expansion. The genetic diversity of these viruses complicates the development of virus-specific vaccines or antivirals, highlighting the need for pan-viral strategies. As the common vector for these pathogens, mosquitoes and specifically their salivary proteins represent a promising target for such interventions. Mosquito saliva, secreted into the skin during biting, has immunomodulatory effects that can enhance host susceptibility to infection, but these mechanisms are not well defined in humans. Methods: The objective of this study was to determine whether AGS-v PLUS, a vaccine targeting mosquito salivary antigens, could modulate the human skin immune response to mosquito biting and potentially promote antiviral bystander immunity. In a Phase I trial, healthy volunteers were vaccinated with AGS-v PLUS (with or without adjuvant) or placebo, and three weeks later, they were exposed to bites from Aedes albopictus and Aedes aegypti mosquitoes. Skin biopsies from bitten and unbitten sites were analysed by transcriptomic profiling. Results: In placebo recipients, mosquito biting elicited a marked adaptive immune response at 48 h, characterised by CD4⁺ Th1 and CD8⁺ T cell signatures and leukocyte recruitment. While responses to Ae. aegypti and Ae. albopictus bites were broadly similar, those to Ae. albopictus were stronger. Vaccination with AGS-v PLUS, particularly with adjuvant, enhanced Th1 and CD8⁺ T cell-associated gene expression while suppressing pathways linked to neutrophilic inflammation and epithelial stress, which together may provide enhanced antiviral capacity. Conclusions: These findings demonstrate that targeting the host response to mosquito saliva via vaccination can reprogram the skin’s immune response to mosquito bites, supporting a novel and broadly applicable pan-viral strategy to mitigate the impact of arboviral diseases. Full article

Disinsection of aircraft and other conveyances is recommended to prevent the international spread of disease-carrying mosquitoes. A systematic review synthesized the effectiveness of adult mosquito disinsection aboard international air, marine, and land conveyances, using literature available up to 31 May 2025. Nineteen experimental trials, nine of which included an unexposed control arm, were synthesized. The studies were generally of poor quality with high risk of bias, and adherence to WHO guidelines was 33.30% (range: 18.20–60.5%). Across comparator trials of aircraft disinsection, the odds of mosquito mortality in the treated groups compared to control groups was 163.60 (95% CI 147–182), and the relative risk of mosquito death was 14.24 (95% CI 12.99–15.63). The direction of effect was consistent across mosquito species, methods of disinsection, types of aircraft, and insecticides, though the magnitude of the effect varied widely. The only WHO-recommended insecticide tested in a controlled trial was 2% d-phenothrin, which demonstrated an odds ratio of 171.70 (95% CI 139.10–212) and a relative risk of 20.08 (95% CI 16.53–24.43) for mosquito mortality. The lack of adherence to WHO guidelines raises uncertainty about the real-world effectiveness of disinsection. Full article