RESUMEN
Vector-borne diseases resulted into several cases of human morbidity and mortality over the years and among them is filariasis, caused by the mosquito Culex quinquefasciatus. Developing novel strategies for mosquito control without jeopardizing the environmental conditions has always been a topic of discussion and research. Integrated Vector Management (IVM) emphasizes a comprehensive approach and use of a range of strategies for vector control. Recent research evaluated the use of two entomopathogenic fungi; Beauveria bassiana and Lecanicillium lecanii in IVM, which can serve as potential organic insecticide for mosquito population control. However, their combined efficacy has not yet been evaluated against mosquito control in prior research and a gap of knowledge is still existing. So, this research was an attempt to bridge up the knowledge gap by (1) Assessing the combined efficacy of Beauveria bassiana and Lecanicillium lecanii on Culex quinquefasciatus (2) To investigate the sub-lethal concentration (LC50) of the combined fungal concentration and (3) To examine the post-mortem effects caused by the combined fungal concentration under Scanning Electron Microscope (SEM). The larval pathogenicity assay was performed on 4th instar C. quinquefasciatus larvae. Individual processed fungal solution of B. bassiana and L. lecanii were procured and to test the combined efficacy, the two solutions were mixed in equal proportions. To evaluate the sub-lethal concentration (LC50), different concentrations of the combined fungal solution were prepared by serial dilations. The mortality was recorded after 24 hours for each concentration. Upon treatment and evaluation, The LC50 values of B. bassiana and L. lecanii were 0.25 x 104 spores/ml and 0.12 x 104 spores/ml respectively and the combined fungal concentration was 0.06 x 103 spores/ml. This clearly indicated that the combined efficacy of the fungi is more significant. Further, SEM analysis revealed morphological deformities and extensive body perforations upon combined fungal treatment. These findings suggested that combining the two fungi can be a more effective way in controlling the population of Culex quinquefasciatus.
Asunto(s)
Beauveria , Culex , Control de Mosquitos , Control Biológico de Vectores , Animales , Culex/microbiología , Beauveria/fisiología , Beauveria/patogenicidad , Control de Mosquitos/métodos , Control Biológico de Vectores/métodos , Mosquitos Vectores/microbiología , Hypocreales/fisiología , Hypocreales/patogenicidadRESUMEN
Mosquito-borne diseases, such as malaria, dengue, and Zika, pose major public health challenges globally, affecting millions of people. The growing resistance of mosquito populations to synthetic insecticides underscores the critical need for effective and environmentally friendly larvicides. Although chemical pesticides can initially be effective, they often lead to negative environmental consequences and health hazards for non-target species, including humans. This study aimed to evaluate the larvicidal effects of Trachyspermum ammi essential oil and Delphinium speciosum extract on the larvae of three major mosquito species: Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. Mosquito larvae of Ae. aegypti, An. stephensi, and Cx. quinquefasciatus were reared under controlled laboratory conditions. The larvicidal activity of T. ammi essential oil and D. speciosum extract was evaluated through standard bioassays, using various concentrations of essential oils (10, 20, 40, 80, and 160 ppm) and extracts (160, 320, 640, 1280, and 2560 ppm) to determine the lethal concentration (LC50) values after 24 h of exposure. Fresh plant materials were collected, with the essential oil extracted via hydro-distillation, and the extract prepared using methanol solvent extraction. The chemical composition of T. ammi essential oil was examined using gas chromatography-mass spectrometry (GC-MS). Additionally, the preliminary analysis of the chemical compounds in D. speciosum extract was carried out using thin layer chromatography (TLC) and nuclear magnetic resonance spectroscopy (NMR) techniques. The results indicated that the essential oil of T. ammi exhibited more effective larvicidal activity compared to the D. speciosum extract. Specifically, the essential oil demonstrated LC50 values of 18 ppm for Cx. quinquefasciatus and 19 ppm for Ae. aegypti. In contrast, the D. speciosum extract showed the strongest larvicidal effect against An. stephensi, with an LC50 of 517 ppm. Concentrations of 40 ppm of the essential oil and 1280 ppm of the extract resulted in 100% mortality across all three species. Both the essential oil of T. ammi and the D. speciosum extract exhibited concentration-dependent larvicidal activity, and these results were statistically significant (p < 0.001) compared to the no-treatment group. GC-MS analysis revealed thymol (88.95%), o-cymen-5-ol (4.11%), and γ-terpinene (2.10%) as the major constituents of the T. ammi essential oil. Additionally, TLC verified the presence of alkaloids in both chloroform and methanolic extracts. Proton NMR identified a diterpene structure for these alkaloids. These findings suggest that T. ammi essential oil is a promising candidate for natural mosquito control strategies. Given its efficacy, further research is warranted to explore its potential in integrated vector management programs.
Asunto(s)
Delphinium , Insecticidas , Larva , Mosquitos Vectores , Aceites Volátiles , Extractos Vegetales , Animales , Aceites Volátiles/farmacología , Aceites Volátiles/química , Larva/efectos de los fármacos , Mosquitos Vectores/efectos de los fármacos , Extractos Vegetales/farmacología , Extractos Vegetales/química , Insecticidas/farmacología , Insecticidas/química , Delphinium/química , Aedes/efectos de los fármacos , Dengue , Malaria/prevención & control , Anopheles/efectos de los fármacos , Filariasis , Culex/efectos de los fármacos , Control de Mosquitos/métodosRESUMEN
BACKGROUND: Microbial larvicides containing both LysiniBacillus sphaericus and Bacillus thuringiensis svar. israelensis (Bti) insecticidal crystals can display advantages for mosquito control. This includes a broader action against larvae that are refractory to the Binary (Bin) toxin from L. sphaericus, as Bin-resistant Culex quinquefasciatus and Aedes aegypti naturally refractory larvae, which often co-habit urban areas of endemic countries for arboviruses. Our principal goal was to assess the toxicity of a combined L. sphaericus/Bti larvicide (Vectomax FG™) to Cx. quinquefasciatus (susceptible CqS and Bin-resistant CqR) and Ae. aegypti (Rocke) and to determine its persistence in the breeding sites with those larvae. METHODS: The toxicity of a combined L. sphaericus/Bti product (VectoMax FG™) to larvae was performed using bioassays, and persistence was evaluated in simulate field trials carried out under the shade, testing two label concentrations during 12 weeks. A laboratory strain SREC, established with CqS and CqR larvae, was kept during four generations to evaluate the ability of the L. sphaericus/Bti to eliminate resistant larvae. RESULTS: The L. sphaericus/Bti showed toxicity (mg/L) to larvae from all strains with a decreasing pattern for CqS (LC50 = 0.006, LC90 = 0.030), CqR (LC50 = 0.009, LC90 = 0.069), and Rocke (LC50 = 0.042, LC90 = 0.086). In a simulated field trial, the larvicide showed a persistence of 6 weeks and 8 weeks, controlling larvae from all strains in containers with 100 L of water, using 2 g or 4 g per container (100 L), respectively. The treatment of SREC larvae with L. sphaericus/Bti showed its capacity to eliminate the Bin-resistant individuals using suitable concentrations to target those larvae. CONCLUSIONS: Our results showed the high efficacy and persistence of the L. sphaericus/Bti larvicide to control Cx. quinquefasciatus and Ae. aegypti that might cohabit breeding sites. These findings demonstrated that such larvicides can be an effective tool for controlling those species in urban areas with a low potential for selecting resistance.
Asunto(s)
Aedes , Bacillaceae , Bacillus thuringiensis , Culex , Insecticidas , Larva , Control de Mosquitos , Control Biológico de Vectores , Animales , Culex/efectos de los fármacos , Aedes/efectos de los fármacos , Larva/efectos de los fármacos , Control de Mosquitos/métodos , Insecticidas/farmacología , Bacillaceae/química , Control Biológico de Vectores/métodos , Resistencia a los Insecticidas , Mosquitos Vectores/efectos de los fármacosRESUMEN
BACKGROUND: Antananarivo, the capital city of Madagascar, is experiencing a steady increase in population growth. Due to the abundance of mosquito vectors in this locality, the population exposed to mosquito-borne diseases is therefore also increasing, as is the risk of epidemic episodes. The aim of the present study was to assess, in a resource-limited setting, the information on mosquito population dynamics and disease transmission risk that can be provided through a longitudinal entomological study carried out in a multi-host single site. METHODS: Mosquitoes were collected every 15 days over 16 months (from January 2017 to April 2018) using six CDC-light traps in a peri-urban area of Antananarivo. Multivariable generalised linear models were developed using indoor and outdoor densities of the predominant mosquito species as response variables and moon illumination, environmental data and climatic data as the explanatory variables. RESULTS: Overall, 46,737 mosquitoes belonging to at least 20 species were collected, of which Culex antennatus (68.9%), Culex quinquefasciatus (19.8%), Culex poicilipes (3.7%) and Anopheles gambiae sensu lato (2.3%) were the most abundant species. Mosquito densities were observed to be driven by moon illumination and climatic factors interacting at different lag periods. The outdoor models demonstrated biweekly and seasonal patterns of mosquito densities, while the indoor models demonstrated only a seasonal pattern. CONCLUSIONS: An important diversity of mosquitoes exists in the peri-urban area of Antananarivo. Some well-known vector species, such as Cx. antennatus, a major vector of West Nile virus (WNV) and Rift-Valley fever virus (RVFV), Cx. quinquefasciatus, a major vector of WNV, Cx. poicilipes, a candidate vector of RVFV and An. gambiae sensu lato, a major vector of Plasmodium spp., are abundant. Importantly, these four mosquito species are present all year round, even though their abundance declines during the cold dry season, with the exception of Cx. quinquefasciatus. The main drivers of their abundance were found to be temperature, relative humidity and precipitation, as well as-for outdoor abundance only-moon illumination. Identifying these drivers is a first step towards the development of pathogen transmission models (R0 models), which are key to inform public health stakeholders on the periods of most risk for vector-borne diseases.
Asunto(s)
Culex , Mosquitos Vectores , Dinámica Poblacional , Animales , Madagascar/epidemiología , Mosquitos Vectores/virología , Mosquitos Vectores/fisiología , Estudios Longitudinales , Culex/virología , Culex/fisiología , Culex/clasificación , Estaciones del Año , Culicidae/virología , Culicidae/fisiología , Culicidae/clasificación , Anopheles/fisiología , Anopheles/virología , Anopheles/clasificación , Humanos , Densidad de Población , Virus del Nilo Occidental , FemeninoRESUMEN
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.
Asunto(s)
Aves , Culex , Conducta Alimentaria , Mosquitos Vectores , Animales , Culex/fisiología , Culex/virología , Culex/clasificación , Ratones , Humanos , Mosquitos Vectores/fisiología , Mosquitos Vectores/virología , Mosquitos Vectores/clasificación , Femenino , Alemania , Irán , Especificidad del Huésped , Virus del Nilo Occidental/fisiología , Virus del Nilo Occidental/genética , Flavivirus/genética , Flavivirus/fisiología , Flavivirus/aislamiento & purificación , Especificidad de la EspecieRESUMEN
West Nile virus (WNV) is the leading cause of mosquito-borne illness in the USA. There are currently no human vaccines or therapies available for WNV, and vector control is the primary strategy used to control WNV transmission. The WNV vector Culex tarsalis is also a competent host for the insect-specific virus (ISV) Eilat virus (EILV). ISVs such as EILV can interact with and cause superinfection exclusion (SIE) against human pathogenic viruses in their shared mosquito host, altering vector competence for these pathogenic viruses. The ability to cause SIE and their host restriction make ISVs a potentially safe tool to target mosquito-borne pathogenic viruses. In the present study, we tested whether EILV causes SIE against WNV in mosquito C6/36 cells and C. tarsalis mosquitoes. The titres of both WNV strains - WN02-1956 and NY99 - were suppressed by EILV in C6/36 cells as early as 48-72 h post-superinfection at both m.o.i. values tested in our study. The titres of WN02-1956 at both m.o.i. values remained suppressed in C6/36 cells, whereas those of NY99 showed some recovery towards the final timepoint. The mechanism of SIE remains unknown, but EILV was found to interfere with NY99 attachment in C6/36 cells, potentially contributing to the suppression of NY99 titres. However, EILV had no effect on the attachment of WN02-1956 or internalization of either WNV strain under superinfection conditions. In C. tarsalis, EILV did not affect the infection rate of either WNV strain at either timepoint. However, in mosquitoes, EILV enhanced NY99 infection titres at 3 days post-superinfection, but this effect disappeared at 7 days post-superinfection. In contrast, WN02-1956 infection titres were suppressed by EILV at 7 days post-superinfection. The dissemination and transmission of both WNV strains were not affected by superinfection with EILV at either timepoint. Overall, EILV caused SIE against both WNV strains in C6/36 cells; however, in C. tarsalis, SIE caused by EILV was strain specific potentially owing to differences in the rate of depletion of shared resources by the individual WNV strains.
Asunto(s)
Culex , Mosquitos Vectores , Sobreinfección , Virus del Nilo Occidental , Animales , Culex/virología , Virus del Nilo Occidental/fisiología , Mosquitos Vectores/virología , Sobreinfección/virología , Línea Celular , Fiebre del Nilo Occidental/transmisión , Fiebre del Nilo Occidental/virología , Replicación ViralRESUMEN
Humans have greatly altered earth's terrestrial water cycle with the majority of fresh water being used for agriculture. Irrigation changes spatial and temporal water availability and alters mosquito abundance and phenology. Previous studies evaluating the effect of irrigation on mosquito abundance and mosquito-borne disease have shown inconsistent results and little is known about the effect of irrigation on variability in mosquito abundance. We examined the effect of irrigation, climate and land cover on mosquito abundance and human West Nile virus (WNV) disease cases across California. Irrigation made up nearly a third of total water inputs, and exceeded precipitation in some regions. Abundance of two key vectors of several arboviruses, including WNV, Culex tarsalis and the Culex pipiens complex, increased 17-21-fold with irrigation. Irrigation reduced seasonal variability in C. tarsalis abundance by 36.1%. Human WNV incidence increased with irrigation, which explained more than a third (34.2%) of the variation in WNV incidence among California counties. These results suggest that irrigation can increase and decouple mosquito populations from natural precipitation variability, resulting in sustained and increased disease burdens. Shifts in precipitation due to climate change are likely to result in increased irrigation in many arid regions which could increase mosquito populations and disease.
Asunto(s)
Riego Agrícola , Culex , Mosquitos Vectores , Fiebre del Nilo Occidental , Virus del Nilo Occidental , Animales , Fiebre del Nilo Occidental/epidemiología , Fiebre del Nilo Occidental/transmisión , Virus del Nilo Occidental/fisiología , Humanos , California/epidemiología , Culex/virología , Culex/fisiología , Incidencia , Mosquitos Vectores/virología , Cambio Climático , Estaciones del AñoRESUMEN
Insect growth regulators, like S-methoprene, are heavily relied upon worldwide for larval mosquito chemical control due to their target specificity and long-lasting effects. In this study, susceptibility to S-methoprene was evaluated in Culex pipiens, a globally important vector species. Populations from 14 sites throughout the Chicago area with a long history of S-methoprene use and two sites with minimal use in Wisconsin were examined. Using a bioassay methodology and probit analyses, LC50 and LC90 values were calculated and compared to a susceptible laboratory strain to develop resistance ratios, then categorized for resistance intensity. The resistance ratios observed required the addition of another category, termed 'extreme' resistance, indicating resistance ratios greater than 100. 'Low' to 'extreme' levels of resistance to S-methoprene were detected throughout Illinois populations, with resistance ratios ranging from 2.33 to 1010.52. Resistance was not detected in populations where S-methoprene pressure has been very limited. These 'extreme' resistance ratios observed have never been documented in a wild vector species mosquito population. The relationships between historical S-methoprene use, resistance detected with laboratory bioassays, and the potential for field product failure remain unclear. However, the profound resistance detected here demonstrates a potential critical threat to protecting public health from mosquito-borne diseases.
Asunto(s)
Culex , Metopreno , Animales , Culex/efectos de los fármacos , Chicago , Metopreno/farmacología , Resistencia a los Insecticidas , Mosquitos Vectores/efectos de los fármacos , Larva/efectos de los fármacos , Control de Mosquitos/métodosRESUMEN
INTRODUCTION: Culex quinquefasciatus is one of the most important carriers of human pathogens. Using the insecticides is one of the most important methods of combating this vector. But the genetic resistance created in Culex quinquefasciatus led to disruption in the fight against this pest. Consequently, it is necessary to know the level of resistance to fight this vector. Based on this, the present study was conducted to investigate the prevalence of kdr resistance in Culex quinquefasciatus against organochlorine insecticides in the world. METHODS: This study was conducted by systematic review, and meta-analysis on the prevalence of kdr resistance and mortality rate in Culex quinquefasciatus against organochlorine insecticides in the world. All pertinent articles were extracted and analyzed in accordance with this information during an unrestricted search of the scientific databases Web of Science, PubMed, Scopus, biooan.org, Embase, ProQuest, and Google Scholar until the end of November 2023. Statistical analysis of data was done using fixed and random effects model in meta-analysis, I2 index, Cochran's test, and meta-regression by STATA version 17 software. RESULTS: Seventy articles were included in the meta-analysis process. Based on the findings, the prevalence of Kdr in Culex quinquefasciatus against organochlorine insecticide was estimated at 63.1%. Moreover, the mortality rate against the insecticide deltamethrin was 46%, DDT 18.5%, permethrin 42.6%, malathion 54.4% and lambdacyhalothrin 53%. CONCLUSION: More than half of Cx. quinquefasciatus had Kdr. This vector was relatively resistant to DDT and permethrin insecticides and sensitive to malathion, deltamethrin and lambdacyhalothrin. In order to prevent the development of resistance to alternative insecticides, it is consequently critical to combat this vector with efficacious insecticides.
Asunto(s)
Culex , Hidrocarburos Clorados , Resistencia a los Insecticidas , Insecticidas , Mosquitos Vectores , Animales , Culex/genética , Culex/efectos de los fármacos , Resistencia a los Insecticidas/genética , Insecticidas/farmacología , Mosquitos Vectores/genética , Mosquitos Vectores/efectos de los fármacos , Hidrocarburos Clorados/farmacología , Enfermedades Transmitidas por Vectores , Humanos , Piretrinas/farmacología , Enfermedades Transmitidas por MosquitosRESUMEN
Mosquitoes, one of the deadliest animals on the planet, cause millions of fatalities each year by transmitting several human illnesses. Synthetic pesticides were previously used to prevent the spread of diseases by mosquitoes, which was effective in protecting humans but caused serious human health problems, environmental damage, and developed mosquito pesticide resistance. This research focuses on exploring new, more effective, safer, and environmentally friendly compounds to improve mosquito vector management. Phytochemicals are possible biological agents for controlling pests and many are target-specific, rapidly biodegradable, and eco-friendly. The potential of extracts of Lantana camara, Melia azedarach, Nerium oleander, Ricinus communis, and Withania somnifera against 3rd instar Culex pipiens (Common house mosquito) larvae was evaluated. Methanol extracts had more toxic effects against Cx. pipiens larvae (95-100%, 24 h post-treatment) than aqueous extracts (63-91%, 24 h post-treatment). The methanol extracts of Nerium oleander (LC50 = 158.92 ppm) and Ricinus communis (LC50 = 175.04 ppm) were very effective at killing mosquito larvae, 24 h after treatment. N. oleander (LC50 = 373.29 ppm) showed high efficacy in aqueous plant extracts. Among the different extracts of the five plants screened, the methanol extract of R. communis recorded the highest ovicidal activity of 5% at 800 ppm concentration. Total developmental duration and growth index were highly affected by R. communis and M. azedarach methanol extracts. In field tests it was clear that plant extracts decreased mosquito larval density, especially when mixed with mosquito Bti briquette, with stability up to seven days for N. oleander. GC-MS results showed that the methanol extract had a higher number of chemical compounds, particularly with more terpene compounds. A high-performance liquid chromatography (HPLC) technique was used to detect the existence of non-volatile polyphenols and flavonoids. All five methanol extracts showed high concentrations of active ingredients such as gallic acid, chlorogenic acid (more than 100 µg/ml) and the rosmarinic acid was also found in all the five extracts in addition to 17 active polyphenols and flavonoids presented at moderate to low concentrations. Molecular modeling of 18 active ingredients detected by the HPLC were performed to the vicinity of one of the fatty acid binding proteins of lm-FABP (PDB code: 2FLJ). Rutin, Caffeic acid, coumaric acid and rosmarinic acid which presented densely in R. communis and N. oleander showed multiple and stable intermolecular hydrogen bonding and π-π stacking interactions. The inhibition ability of the fatty acid binding protein, FABP4, was evaluated with remarkable receptor inhibition evident, especially with R. communis and N. oleander having inhibitory concentrations of IC50 = 0.425 and 0.599 µg/mL, respectively. The active phytochemical compounds in the plants suggest promising larvicidal and ovicidal activity, and have potential as a safe and effective alternative to synthetic insecticides.
Asunto(s)
Culex , Insecticidas , Larva , Mosquitos Vectores , Nerium , Extractos Vegetales , Plantas Medicinales , Animales , Extractos Vegetales/farmacología , Extractos Vegetales/química , Culex/efectos de los fármacos , Culex/crecimiento & desarrollo , Larva/efectos de los fármacos , Insecticidas/farmacología , Insecticidas/química , Plantas Medicinales/química , Mosquitos Vectores/efectos de los fármacos , Nerium/química , Virus del Nilo Occidental/efectos de los fármacos , Lantana/química , Ricinus/química , Melia azedarach/química , Control de Mosquitos/métodos , Fiebre del Nilo OccidentalRESUMEN
A new series of substituted benzo[h]chromene, benzochromenopyrimidine, and benzochromenotriazolopyrimidine derivatives were synthesized via chemical transformations of iminonitrile, ethoxymethylene amino, and cyanomethylene functionalities. The chemical structures of the synthesized compounds were assured by spectroscopic data and elemental analysis. The larvicidal efficacy of these compounds against Culex pipiens L. larvae was investigated, revealing potent insecticidal activity, particularly for compounds 6, 10, and 16, exceeding that of the standard insecticide chlorpyrifos. The mode of action of these compounds was explored through molecular docking studies, indicating their potential as acetylcholine esterase (AChE) inhibitors and nicotinic acetylcholine receptors (nAChR) blockers. The structure-activity relationship analysis highlighted the influence of substituents and fused heterocyclic rings on larvicidal potency. These findings suggest that the synthesized compounds hold promise as potential candidates for developing novel and effective mosquito control agents.
Asunto(s)
Benzopiranos , Culex , Insecticidas , Larva , Simulación del Acoplamiento Molecular , Animales , Culex/efectos de los fármacos , Larva/efectos de los fármacos , Insecticidas/farmacología , Insecticidas/química , Insecticidas/síntesis química , Relación Estructura-Actividad , Benzopiranos/farmacología , Benzopiranos/química , Benzopiranos/síntesis química , Modelos Moleculares , Inhibidores de la Colinesterasa/farmacología , Inhibidores de la Colinesterasa/síntesis química , Inhibidores de la Colinesterasa/química , Receptores Nicotínicos/metabolismo , Estructura MolecularRESUMEN
Malaria has a historical presence in the Dakshina Kannada (D.K.) and Udupi districts of Karnataka, India. To understand the potential involvement of anopheline fauna in malaria transmission, we conducted an exploratory entomological survey. The study is crucial given the decreasing malaria incidence in these districts in recent years. From September 2022 to August 2023, we collected indoor resting mosquitoes using a manual aspirator at 27 randomly chosen sites within three distinct resting habitats (human dwellings, cattle sheds, and construction sites) in the urban areas of Udupi and Dakshina Kannada districts. Mosquitoes were morphologically identified, and anopheline specimens were tested for the presence of malarial parasite by polymerase chain reaction (PCR) analysis. We collected a total of 1810 mosquitoes, comprising 21 species distributed across five genera. Culex emerged as the predominant genus, constituting 84.4% of the collected specimens, while Anopheles accounted for 5.4%. Among the observed species, Culex quinquefasciatus was predominant, comprising 77.9% of the mosquito specimens collected in this study. Two malaria vectors, An. stephensi and An. subpictus complex, constituted 16.3% and 1.0% of the total anophelines collected, respectively. None of the 96 female anophelines was tested positive for Plasmodium infection. Our findings suggest that Anopheles mosquitoes prefer resting in cattle sheds over human dwellings. While our study identified two malaria vectors, they were present at low densities. To gain a more comprehensive understanding of the dynamics of these vector mosquitoes, it is essential to conduct long-term surveillance to monitor their prevalence and role in malaria transmission.
Asunto(s)
Anopheles , Ecosistema , Malaria , Mosquitos Vectores , Animales , India/epidemiología , Anopheles/parasitología , Anopheles/fisiología , Anopheles/clasificación , Mosquitos Vectores/parasitología , Mosquitos Vectores/fisiología , Malaria/transmisión , Malaria/epidemiología , Malaria/parasitología , Humanos , Prevalencia , Plasmodium/aislamiento & purificación , Plasmodium/clasificación , Plasmodium/fisiología , Bovinos , Femenino , Culex/parasitología , Culex/fisiologíaRESUMEN
Musca domestica L., a common housefly, and Culex quinquefasciatus mosquito are quite well-known pests that can transfer a wide range of diseases to humans as well as animals. In this study, various isoborneol derivatives including esters, ethers, and thioethers were synthesized from isoborneol under mild conditions. These derivatives were evaluated for inhibition of house-fly M. domestica adults and Cx. quinquefasciatus larvae. Two of the synthesized isoborneol ester derivatives (2 and 3) showed good activity against both insect species. Additional two derivatives (6 and 9) were active against M. domestica L., and the derivatives (1-3, 8) were active against Cx. quinquefasciatus larvae.
Asunto(s)
Culex , Moscas Domésticas , Insecticidas , Larva , Animales , Moscas Domésticas/efectos de los fármacos , Culex/efectos de los fármacos , Insecticidas/farmacología , Insecticidas/química , Larva/efectos de los fármacosRESUMEN
Avian malaria is expanding upslope with warmer temperatures and driving multiple species of Hawaiian birds towards extinction. Methods to reduce malaria transmission are urgently needed to prevent further declines. Releasing Wolbachia-infected incompatible male mosquitoes could suppress mosquito populations and releasing Wolbachia-infected female mosquitoes (or both sexes) could reduce pathogen transmission if the Wolbachia strain reduced vector competence. We cleared Culex quinquefasciatus of their natural Wolbachia pipientis wPip infection and transinfected them with Wolbachia wAlbB isolated from Aedes albopictus. We show that wAlbB infection was transmitted transovarially, and demonstrate cytoplasmic incompatibility with wild-type mosquitoes infected with wPip from Oahu and Maui, Hawaii. We measured vector competence for avian malaria, Plasmodium relictum, lineage GRW4, of seven mosquito lines (two with wAlbB; three with natural wPip infection, and two cleared of Wolbachia infection) by allowing them to feed on canaries infected with recently collected field isolates of Hawaiian P. relictum. We tested 73 groups (Ntotal = 1176) of mosquitoes for P. relictum infection in abdomens and thoraxes 6-14 days after feeding on a range of parasitemias from 0.028% to 2.49%, as well as a smaller subset of salivary glands. We found no measurable effect of Wolbachia on any endpoint, but strong effects of parasitemia, days post feeding, and mosquito strain on both abdomen and thorax infection prevalence. These results suggest that releasing male wAlbB-infected C. quinquefasciatus mosquitoes could suppress wPip-infected mosquito populations, but would have little positive or negative impact on mosquito vector competence for P. relictum if wAlbB became established in local mosquito populations. More broadly, the lack of Wolbachia effects on vector competence we observed highlights the variable impacts of both native and transinfected Wolbachia infections in mosquitoes.
Asunto(s)
Culex , Malaria Aviar , Mosquitos Vectores , Plasmodium , Wolbachia , Animales , Femenino , Masculino , Aedes/microbiología , Culex/microbiología , Culex/parasitología , Hawaii , Malaria Aviar/transmisión , Mosquitos Vectores/microbiología , Mosquitos Vectores/parasitología , Wolbachia/fisiologíaRESUMEN
Plants are a treasure trove of biological materials containing a wide range of potential phytochemicals that are target-specific, rapidly biodegradable, and environmentally friendly, with multiple medicinal effects. Unfortunately, the development of resistance to synthetic pesticides and antibiotics led to the discovery of new antibiotics, antioxidants, and biopesticides. This has also led to the creation of new medications that work very well. The current study aimed to prove that ornamental plants contain specialized active substances that are used in several biological processes. Mosquitoes, one of the deadliest animals on the planet, cause millions of fatalities each year by transmitting several human illnesses. Phytochemicals are possible biological agents for controlling pests that are harmful. The potential of leaf extracts of Bougainvillea glabra, Delonix regia, Lantana camara, and Platycladus orientalis against Culex pipiens and microbial agents was evaluated. Acetone extracts had more toxic effects against Cx. pipiens larvae (99.0-100 %, 72 h post-treatment), and the LC50 values were 142.8, 189.5, 95.4, and 71.1 ppm for B. glabra, D. regia, L. camara, and P. orientalis, respectively. Plant extracts tested in this study showed high insecticidal, antimicrobial, and antioxidant potential. GC-MS and HPLC analyses showed a higher number of terpenes, flavonoids, and phenolic compounds. The ADME analysis of element, caryophyllene oxide, caryophyllene, and copaene showed that they were similar to drugs and that they were better absorbed by the body and able to pass through the blood-brain barrier. Our results confirm the ability of ornamental plants to have promising larvicidal and antimicrobial activity and biotechnology.
Asunto(s)
Culex , Insecticidas , Lantana , Larva , Nyctaginaceae , Extractos Vegetales , Hojas de la Planta , Animales , Extractos Vegetales/farmacología , Extractos Vegetales/química , Culex/efectos de los fármacos , Lantana/química , Insecticidas/farmacología , Nyctaginaceae/química , Hojas de la Planta/química , Larva/efectos de los fármacos , Metabolómica , Mosquitos Vectores/efectos de los fármacos , Fitoquímicos/farmacología , Fitoquímicos/química , Antioxidantes/farmacología , Fiebre del Nilo OccidentalRESUMEN
West Nile virus (WNV) is the leading mosquito-borne disease causing-pathogen in the United States. Concerningly, there are no prophylactics or drug treatments for WNV and public health programs rely heavily on vector control efforts to lessen disease incidence. Insecticides can be effective in reducing vector numbers if implemented strategically, but can diminish in efficacy and promote insecticide resistance otherwise. Vector control programs which employ mass-fogging applications of insecticides, often conduct these methods during the late-night hours, when diel temperatures are coldest, and without a-priori knowledge on daily mosquito activity patterns. This study's aims were to 1) quantify the effect of temperature on the toxicity of two conventional insecticides used in fogging applications (malathion and deltamethrin) to Culex tarsalis, an important WNV vector, and 2) quantify the time of host-seeking of Cx. tarsalis and other local mosquito species in Maricopa County, Arizona. The temperature-toxicity relationship of insecticides was assessed using the WHO tube bioassay, and adult Cx. tarsalis, collected as larvae, were exposed to three different insecticide doses at three temperature regimes (15, 25, and 35°C; 80% RH). Time of host-seeking was assessed using collection bottle rotators with encephalitis vector survey traps baited with dry ice, first at 3h intervals during a full day, followed by 1h intervals during the night-time. Malathion became less toxic at cooler temperatures at all doses, while deltamethrin was less toxic at cooler temperatures at the low dose. Regarding time of host-seeking, Cx. tarsalis, Aedes vexans, and Culex quinquefasciatus were the most abundant vectors captured. During the 3-hour interval surveillance over a full day, Cx. tarsalis were most-active during post-midnight biting (00:00-06:00), accounting for 69.0% of all Cx. tarsalis, while pre-midnight biting (18:00-24:00) accounted for 30.0% of Cx. tarsalis. During the 1-hour interval surveillance overnight, Cx. tarsalis were most-active during pre-midnight hours (18:00-24:00), accounting for 50.2% of Cx. tarsalis captures, while post-midnight biting (00:00-06:00) accounted for 49.8% of Cx. tarsalis. Our results suggest that programs employing large-scale applications of insecticidal fogging should consider temperature-toxicity relationships coupled with time of host-seeking data to maximize the efficacy of vector control interventions in reducing mosquito-borne disease burden.
Asunto(s)
Culex , Insecticidas , Control de Mosquitos , Mosquitos Vectores , Nitrilos , Piretrinas , Temperatura , Fiebre del Nilo Occidental , Virus del Nilo Occidental , Animales , Culex/efectos de los fármacos , Culex/virología , Insecticidas/farmacología , Mosquitos Vectores/virología , Mosquitos Vectores/efectos de los fármacos , Mosquitos Vectores/fisiología , Control de Mosquitos/métodos , Nitrilos/farmacología , Piretrinas/farmacología , Virus del Nilo Occidental/efectos de los fármacos , Virus del Nilo Occidental/fisiología , Fiebre del Nilo Occidental/transmisión , Fiebre del Nilo Occidental/prevención & control , Malatión/farmacología , Conducta de Búsqueda de Hospedador/efectos de los fármacos , Femenino , ArizonaRESUMEN
In the last 2 decades, there has been an increase in the geographic range and frequency of vector-borne diseases. Management of mosquito populations has become challenging due to increasing rates of resistance to existing insecticidal products and formulations. Several alternative tools have emerged to suppress or replace mosquito populations. One of these tools is the In2Care Mosquito Station (In2Care station). This dual-action station contains the insect growth regulator pyriproxyfen which disrupts the development of immatures and the entomopathogenic fungus Beauveria bassiana (B. bassiana) strain GHA which kills exposed adult mosquitoes. The In2Care stations have previously been shown to effectively control Aedes aegypti in field settings at a density of 6 stations/acre rather than the label-recommended 10 stations/acre. To further test the efficacy of low station density deployment, we deployed In2Care stations in the Pleasant Street Historic District of Gainesville, Florida, at a density of 3 stations/acre over a period of 2 years in the presence or absence of ground larvicidal applications. The deployment of stations resulted in no measurable impact on Ae. aegypti and Culex quinquefasciatus adult or immature abundance suggesting that the low-density deployment of In2Care stations is insufficient to reduce Ae. aegypti and Cu. quinquefasciatus abundance within treatment areas.
Asunto(s)
Aedes , Beauveria , Culex , Control de Mosquitos , Animales , Aedes/crecimiento & desarrollo , Control de Mosquitos/métodos , Culex/crecimiento & desarrollo , Florida , Beauveria/fisiología , Piridinas , Control Biológico de Vectores/métodos , Hormonas Juveniles , Insecticidas , Larva/crecimiento & desarrollo , Densidad de Población , FemeninoRESUMEN
Discarded vehicle tires serve as habitat for mosquito vectors. In New Orleans, Louisiana, discarded tires are an increasingly important public concern, especially considering that the city is home to many medically important mosquito species. Discarded tires are known to be associated with mosquito abundance, but how their presence interacts with other socioenvironmental gradients to influence mosquito ecology is poorly understood. Here, we ask whether discarded tire distribution could be explained by social factors, particularly median income, home vacancy and human population density, and whether these factors interact with urban heat islands (UHI) to drive mosquito vector assemblages. We surveyed tire piles across the city and adult mosquitoes in 12 sites, between May and October of 2020. We compared this data with the social indicators selected and UHI estimates. Our results show that median income and human population density were inversely related to tire abundance. Tire abundance was positively associated with Aedes albopictus abundance in places of low heat (LS) severity. Heat was the only predictor for the other monitored species, where high heat corresponded to higher abundance of Aedes aegypti, and LS to higher abundance of Culex quinquefasciatus. Our results suggest that low-income, sparsely populated neighborhoods of New Orleans may be hotspots for discarded vehicle tires, and are associated with higher abundances of at least one medically important mosquito (Ae. albopictus). These findings suggest potential locations for prioritizing source reduction efforts to control mosquito vectors and highlight discarded tires as a potential exposure pathway to unequal disease risk for low-income residents.
Asunto(s)
Mosquitos Vectores , Animales , Nueva Orleans , Mosquitos Vectores/fisiología , Aedes/fisiología , Humanos , Densidad de Población , Culicidae/fisiología , Factores Socioeconómicos , Culex/fisiologíaRESUMEN
The common house mosquito (Culex pipiens) is a native vector for West Nile virus (WNV). Invasive species like the tiger mosquito (Aedes albopictus) and Asian bush mosquito (Aedes japonicus) are rapidly spreading through Europe, posing a major threat as vectors for dengue, chikungunya (CHIKV), and Japanese encephalitis virus (JEV). These mosquitoes share a similar ecological niche as larvae, but the carry-over effects of aquatic larval interactions to the terrestrial adult stage remain largely unknown and their medical relevance requires further investigation. This study examines the context dependency of larval interactions among Aedes albopictus, Aedes japonicus, and Culex pipiens. The survival, development time, growth, and energetic storage were measured in different European populations within density-response (intraspecific) experiments and replacement (interspecific) experiments at 20 °C and 26 °C. Overall, Ae. japonicus was the weakest competitor, while competition between Ae. albopictus and Cx. pipiens varied with temperature. Adults emerging from this larval competition were infected as follows: Culex pipiens with WNV, Ae. albopictus with CHIKV, and Ae. japonicus with JEV. While no JEV infection was observed, mosquitoes experiencing interspecific interactions during their larval stages exhibited higher infection rates and viral RNA titers for CHIKV and WNV. This increased susceptibility to viral infection after larval competition suggests a higher risk of arbovirus transmission in co-occurring populations.
Asunto(s)
Aedes , Culex , Larva , Mosquitos Vectores , Animales , Culex/virología , Culex/crecimiento & desarrollo , Aedes/virología , Aedes/crecimiento & desarrollo , Aedes/fisiología , Larva/virología , Mosquitos Vectores/virología , Mosquitos Vectores/crecimiento & desarrollo , Infecciones por Arbovirus/transmisión , Infecciones por Arbovirus/virología , Arbovirus/fisiología , Virus del Nilo Occidental/fisiología , Femenino , Virus Chikungunya/fisiología , Virus de la Encefalitis Japonesa (Especie)/fisiologíaRESUMEN
We report the 1st records of Aedes tormentor and Culex panocossa throughout vector surveillance events carried out in putative foci of eastern equine encephalitis in Tamaulipas, Mexico. Formerly, Ae. tormentor had been reported in, at least, 2 Central American countries and Mexico. In Mexico, reports were from the states of Campeche, Chiapas, Quintana Roo, and Veracruz. Records of Ae. tormentor in these 4 Neotropical states were recently reviewed and eliminated; thus, the southernmost geographic distribution for this species is considered to be the state of Tamaulipas Mexico in its neotropical zone. Further, Cx. panocossa had been collected in Guerrero, Tabasco, and Veracruz. In Tamaulipas, there are 82 species of mosquitoes, being the 4th state accounting for the highest mosquito species diversity of 11 states in which comprehensive studies have been conducted on the subject of mosquito distribution.