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1.
Parasit Vectors ; 17(1): 285, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38956650

RESUMO

Usutu virus is an emerging pathogen transmitted by mosquitoes. Culex modestus mosquitoes are widespread in Europe, but their role in disease transmission is poorly understood. Recent data from a single infectious mosquito suggested that Culex modestus could be an unrecognized vector for Usutu virus. In this study, our aim was to corroborate this finding using a larger sample size. We collected immature Culex modestus from a reedbed pond in Flemish Brabant, Belgium, and reared them in the laboratory until the third generation. Adult females were then experimentally infected with Usutu virus in a blood meal and incubated at 25 °C for 14 days. The presence of Usutu virus in the saliva, head and body of each female was determined by plaque assay and quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR). The transmission efficiency was 54% (n = 15/28), confirming that Belgian Culex modestus can experimentally transmit Usutu virus.


Assuntos
Culex , Infecções por Flavivirus , Flavivirus , Mosquitos Vetores , Animais , Culex/virologia , Feminino , Mosquitos Vetores/virologia , Flavivirus/genética , Flavivirus/fisiologia , Bélgica , Infecções por Flavivirus/transmissão , Infecções por Flavivirus/virologia , Saliva/virologia
2.
Parasit Vectors ; 17(1): 286, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38956733

RESUMO

The flavivirus West Nile Virus (WNV), which is transmitted by mosquitoes, poses a significant threat to both humans and animals, and its outbreaks often challenge public health in Europe and other continents. In recent years, there is an increasing trend of WNV incidence rates across several European countries. However, whether there is a year-round circulation or seasonal introduction has yet to be elucidated. Real-time polymerase chain reaction (PCR) identified WNV-positive Culex pipiens mosquitos in 6 out of 146 pools examined in winter 2022 that correspond to three out of the 24 study areas, located in two coastal regions units in Attica, Greece. Spatial dispersion of the six positive pools in the same region suggests a clustered circulation of WNV during the winter of 2022. This is the first study that documents the identification of WNV in Cx. pipiens populations, captured in adult traps during winter period. Our findings underscore the need to extend entomological surveillance programs to include the winter period, specifically in temperate climates and historically affected areas by WNV.


Assuntos
Culex , Mosquitos Vetores , Estações do Ano , Febre do Nilo Ocidental , Vírus do Nilo Ocidental , Animais , Culex/virologia , Vírus do Nilo Ocidental/genética , Vírus do Nilo Ocidental/isolamento & purificação , Vírus do Nilo Ocidental/fisiologia , Grécia/epidemiologia , Febre do Nilo Ocidental/transmissão , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/virologia , Mosquitos Vetores/virologia , Reação em Cadeia da Polimerase em Tempo Real
3.
PLoS One ; 19(7): e0300368, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38985752

RESUMO

BACKGROUND: A treated fabric device for emanating the volatile pyrethroid transfluthrin was recently developed in Tanzania that protected against night-biting Anopheles and Culex mosquitoes for several months. Here perceptions of community end users provided with such transfluthrin emanators, primarily intended to protect them against day-active Aedes vectors of human arboviruses that often attack people outdoors, were assessed in Port-au-Prince, Haiti. METHODS: Following the distribution of transfluthrin emanators to participating households in poor-to-middle class urban neighbourhoods, questionnaire surveys and in-depth interviews of end-user households were supplemented with conventional and Photovoice-based focus group discussions. Observations were assessed synthetically to evaluate user perceptions of protection and acceptability, and to solicit advice for improving and promoting them in the future. RESULTS: Many participants viewed emanators positively and several outlined various advantages over current alternatives, although some expressed concerns about smell, health hazards, bulkiness, unattractiveness and future cost. Most participants expressed moderate to high satisfaction with protection against mosquitoes, especially indoors. Protection against other arthropod pests was also commonly reported, although satisfaction levels were highly variable. Diverse use practices were reported, some of which probably targeted nocturnal Culex resting indoors, rather than Aedes attacking them outdoors during daylight hours. Perceived durability of protection varied: While many participants noted some slow loss over months, others noted rapid decline within days. A few participants specifically attributed efficacy loss to outdoor use and exposure to wind or moisture. Many expressed stringent expectations of satisfactory protection levels, with even a single mosquito bite considered unsatisfactory. Some participants considered emanators superior to fans, bedsheets, sprays and coils, but it is concerning that several preferred them to bed nets and consequently stopped using the latter. CONCLUSIONS: The perspectives shared by Haitian end-users are consistent with those from similar studies in Brazil and recent epidemiological evidence from Peru that other transfluthrin emanator products can protect against arbovirus infection. While these encouraging sociological observations contrast starkly with evidence of essentially negligible effects upon Aedes landing rates from parallel entomological assessments across Haiti, Tanzania, Brazil and Peru, no other reason to doubt the generally encouraging views expressed herein by Haitian end users could be identified.


Assuntos
Ciclopropanos , Fluorbenzenos , Controle de Mosquitos , Haiti , Animais , Humanos , Controle de Mosquitos/métodos , Feminino , Masculino , Inseticidas , Adulto , Mosquitos Vetores , Aedes/efeitos dos fármacos , Pessoa de Meia-Idade , Inquéritos e Questionários , Anopheles/efeitos dos fármacos , Culex/efeitos dos fármacos
4.
BMC Genomics ; 25(1): 673, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38969975

RESUMO

BACKGROUND: Culex tritaeniorhynchus is widely distributed in China, from Hainan Island in the south to Heilongjiang in the north, covering tropical, subtropical, and temperate climate zones. Culex tritaeniorhynchus carries 19 types of arboviruses. It is the main vector of the Japanese encephalitis virus (JEV), posing a serious threat to human health. Understanding the effects of environmental factors on Culex tritaeniorhynchus can provide important insights into its population structure or isolation patterns, which is currently unclear. RESULTS: In total, 138 COI haplotypes were detected in the 552 amplified sequences, and the haplotype diversity (Hd) value increased from temperate (0.534) to tropical (0.979) regions. The haplotype phylogeny analysis revealed that the haplotypes were divided into two high-support evolutionary branches. Temperate populations were predominantly distributed in evolutionary branch II, showing some genetic isolation from tropical/subtropical populations and less gene flow between groups. The neutral test results of HNQH (Qionghai) and HNHK(Haikou) populations were negative (P < 0.05), indicating many low-frequency mutations in the populations and that the populations might be in the process of expansion. Moreover, Wolbachia infection was detected only in SDJN (Jining) (2.24%), and all Wolbachia genotypes belonged to supergroup B. To understand the influence of environmental factors on mosquito-borne viruses, we examined the prevalence of Culex tritaeniorhynchus infection in three ecological environments in Shandong Province. We discovered that the incidence of JEV infection was notably greater in Culex tritaeniorhynchus from lotus ponds compared to those from irrigation canal regions. In this study, the overall JEV infection rate was 15.27 per 1000, suggesting the current risk of Japanese encephalitis outbreaks in Shandong Province. CONCLUSIONS: Tropical and subtropical populations of Culex tritaeniorhynchus showed higher genetic diversity and those climatic conditions provide great advantages for the establishment and expansion of Culex tritaeniorhynchus. There are differences in JEV infection rates in wild populations of Culex tritaeniorhynchus under different ecological conditions. Our results suggest a complex interplay of genetic differentiation, population structure, and environmental factors in shaping the dynamics of Culex tritaeniorhynchus. The low prevalence of Wolbachia in wild populations may reflect the recent presence of Wolbachia invasion in Culex tritaeniorhynchus.


Assuntos
Culex , Haplótipos , Filogenia , Culex/genética , Culex/virologia , Culex/microbiologia , Animais , China , Clima , Variação Genética , Genética Populacional , Wolbachia/genética , Mosquitos Vetores/genética , Mosquitos Vetores/virologia , Mosquitos Vetores/microbiologia , Complexo IV da Cadeia de Transporte de Elétrons/genética
5.
Molecules ; 29(11)2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38893531

RESUMO

In this study, the chemical composition, repellent, and oviposition deterrent effects of five plant essential oils (EOs) extracted from Lantana camara (Verbenaceae), Schinus terebinthifolia (Anacardiaceae), Callistemon viminalis (Myrtaceae), Helichrysum odoratissimum (Asteraceae), and Hyptis suaveolens (Lamiaceae) were evaluated against Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus. When tested at 33.3 µg/cm2, L. camara, S. terebinthifolia, C. viminalis, and H. odoratissimum were effective repellents against Ae. aegypti (89%, 91%, 90%, and 51% repellency, respectively), but they were less repellent against An. gambiae (66%, 86%, 59%, and 49% repellency, respectively). Interestingly, L. camara, S. terebinthifolia, C. viminalis, and H. odoratissimum exhibited 100% repellency against Cx. quinquefasciatus at 33.3 µg/cm2. In time-span bioassays performed at 333 µg/cm2, the EO of L. camara exhibited 100% repellence against Ae. aegypti and An. gambiae for up to 15 min and against Cx. quinquefasciatus for 75 min. The oviposition bioassays revealed that L. camara exhibited the highest activity, showing 85%, 59%, and 89% oviposition deterrence against Ae. aegypti, An. gambiae, and Cx. quinquefasciatus, respectively. The major compounds of L. camara, S. terebinthifolia, and C. viminalis were trans-ß-caryophyllene (16.7%), α-pinene (15.5%), and 1,8-cineole (38.1%), respectively. In conclusion, the L. camara and S. terebinthifolia EOs have the potential to be natural mosquito repellents.


Assuntos
Aedes , Repelentes de Insetos , Óleos Voláteis , Oviposição , Animais , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Repelentes de Insetos/farmacologia , Repelentes de Insetos/química , Oviposição/efeitos dos fármacos , Aedes/efeitos dos fármacos , Culex/efeitos dos fármacos , Anopheles/efeitos dos fármacos , Anopheles/fisiologia , Culicidae/efeitos dos fármacos , Óleos de Plantas/farmacologia , Óleos de Plantas/química , Lantana/química , Anacardiaceae/química , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Feminino
6.
Parasit Vectors ; 17(1): 270, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38926834

RESUMO

BACKGROUND: Cache Valley virus (CVV) is an understudied Orthobunyavirus with a high spillover transmission potential due to its wide geographical distribution and large number of associated hosts and vectors. Although CVV is known to be widely distributed throughout North America, no studies have explored its geography or employed computational methods to explore the mammal and mosquito species likely participating in the CVV sylvatic cycle. METHODS: We used a literature review and online databases to compile locality data for CVV and its potential vectors and hosts. We linked location data points with climatic data via ecological niche modeling to estimate the geographical range of CVV and hotspots of transmission risk. We used background similarity tests to identify likely CVV mosquito vectors and mammal hosts to detect ecological signals from CVV sylvatic transmission. RESULTS: CVV distribution maps revealed a widespread potential viral occurrence throughout North America. Ecological niche models identified areas with climate, vectors, and hosts suitable to maintain CVV transmission. Our background similarity tests identified Aedes vexans, Culiseta inornata, and Culex tarsalis as the most likely vectors and Odocoileus virginianus (white-tailed deer) as the most likely host sustaining sylvatic transmission. CONCLUSIONS: CVV has a continental-level, widespread transmission potential. Large areas of North America have suitable climate, vectors, and hosts for CVV emergence, establishment, and spread. We identified geographical hotspots that have no confirmed CVV reports to date and, in view of CVV misdiagnosis or underreporting, can guide future surveillance to specific localities and species.


Assuntos
Vírus Bunyamwera , Ecossistema , Mosquitos Vetores , Animais , Mosquitos Vetores/virologia , América do Norte/epidemiologia , Culicidae/virologia , Infecções por Bunyaviridae/transmissão , Infecções por Bunyaviridae/epidemiologia , Infecções por Bunyaviridae/virologia , Geografia , Culex/virologia , Aedes/virologia , Mamíferos/virologia , Cervos/virologia , Humanos , Ecologia
7.
Pestic Biochem Physiol ; 202: 105906, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38879292

RESUMO

Early detection of insecticide resistance is essential to develop resistance countermeasures and depends on accurate and rapid biological and biochemical tests to monitor resistance and detect associated mechanisms. Many such studies have measured activities of esterases, enzymes associated with resistance to ester- containing insecticides, using the model substrate, α-naphthyl acetate (α-NA). However, in the field, pests are exposed to ester-containing insecticides such as malathion, that are structurally distinct from α-NA. In the current study, malathion resistance in C. quinquefasciatus (3.2- to 10.4-fold) was highly associated with esterase activity measured with either α-NA (R2 = 0.92) or malathion (R2 = 0.90). In addition, genes encoding two esterases (i.e., EST-2 and EST-3) were over-expressed in field- collected strains, but only one (EST-3) was correlated with malathion hydrolysis (R2 = 0.94) and resistance (Rs = 0.96). These results suggest that, in the strains studied, α-NA is a valid surrogate for measuring malathion hydrolysis, and that heightened expression of an esterase gene is not necessarily associated with metabolic resistance to insecticidal esters.


Assuntos
Culex , Esterases , Resistência a Inseticidas , Inseticidas , Malation , Malation/farmacologia , Animais , Esterases/metabolismo , Esterases/genética , Culex/efeitos dos fármacos , Culex/genética , Culex/enzimologia , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Naftalenos/farmacologia , Hidrólise , Biomarcadores/metabolismo , Proteínas de Insetos/metabolismo , Proteínas de Insetos/genética , Naftóis
8.
Parasit Vectors ; 17(1): 251, 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38858771

RESUMO

BACKGROUND: Salinity, exacerbated by rising sea levels, is a critical environmental cue affecting freshwater ecosystems. Predicting ecosystem structure in response to such changes and their implications for the geographical distribution of arthropod disease vectors requires further insights into the plasticity and adaptability of lower trophic level species in freshwater systems. Our study investigated whether populations of the mosquito Culex pipiens, typically considered sensitive to salt, have adapted due to gradual exposure. METHODS: Mesocosm experiments were conducted to evaluate responses in life history traits to increasing levels of salinity in three populations along a gradient perpendicular to the North Sea coast. Salt concentrations up to the brackish-marine transition zone (8 g/l chloride) were used, upon which no survival was expected. To determine how this process affects oviposition, a colonization experiment was performed by exposing the coastal population to the same concentrations. RESULTS: While concentrations up to the currently described median lethal dose (LD50) (4 g/l) were surprisingly favored during egg laying, even the treatment with the highest salt concentration was incidentally colonized. Differences in development rates among populations were observed, but the influence of salinity was evident only at 4 g/l and higher, resulting in only a 1-day delay. Mortality rates were lower than expected, reaching only 20% for coastal and inland populations and 41% for the intermediate population at the highest salinity. Sex ratios remained unaffected across the tested range. CONCLUSIONS: The high tolerance to salinity for all key life history parameters across populations suggests that Cx. pipiens is unlikely to shift its distribution in the foreseeable future, with potential implications for the disease risk of associated pathogens.


Assuntos
Culex , Oviposição , Salinidade , Animais , Culex/fisiologia , Culex/efeitos dos fármacos , Culex/crescimento & desenvolvimento , Feminino , Masculino , Ecossistema , Tolerância ao Sal , Água Doce , Características de História de Vida , Mosquitos Vetores/fisiologia , Dose Letal Mediana , Cloreto de Sódio/farmacologia
9.
PLoS Negl Trop Dis ; 18(6): e0012295, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38935783

RESUMO

Usutu virus (USUV) is a zoonotic arbovirus infecting mainly wild birds. It is transmitted by ornithophilic mosquitoes, mainly of the genus Culex from birds to birds and to several vertebrate dead-end hosts. Several USUV lineages, differing in their virulence have emerged in the last decades and now co-circulate in Europe, impacting human populations. However, their relative transmission and effects on their mosquito vectors is still not known. We thus compared the vector competence and survival of Culex pipiens mosquitoes experimentally infected with two distinct USUV lineages, EU2 and EU3, that are known to differ in their virulence and replication in vertebrate hosts. Infection rate was variable among blood feeding assays but variations between EU2 and EU3 lineages were consistent suggesting that Culex pipiens was equally susceptible to infection by both lineages. However, EU3 viral load increased with viral titer in the blood meal while EU2 viral load was high at all titers which suggest a greater replication of EU2 than EU3 in mosquito. While their relative transmission efficiencies are similar, at least at low blood meal titer, positive correlation between transmission and blood meal titer was observed for EU3 only. Contrary to published results in vertebrates, EU3 induced a higher mortality to mosquitoes (i.e. virulence) than EU2 whatever the blood meal titer. Therefore, we found evidence of lineage-specific differences in vectorial capacity and virulence to both the vector and vertebrate host which lead to balanced propagation of both viral lineages. These results highlight the need to decipher the interactions between vectors, vertebrate hosts, and the diversity of arbovirus lineages to fully understand transmission dynamics.


Assuntos
Culex , Infecções por Flavivirus , Flavivirus , Mosquitos Vetores , Animais , Culex/virologia , Mosquitos Vetores/virologia , Virulência , Flavivirus/patogenicidade , Flavivirus/genética , Flavivirus/fisiologia , Infecções por Flavivirus/transmissão , Infecções por Flavivirus/virologia , Carga Viral , Feminino , Humanos , Replicação Viral
10.
Int J Biol Macromol ; 273(Pt 2): 133072, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38885861

RESUMO

Plants contain a wide range of potential phytochemicals that are target-specific, and less toxic to human health. The present study aims to investigate the metabolomic profile of Nephrolepis exaltata (L.) Schott and its potential for mosquito control by targeting Glutathione-S-Transferase, focusing on the larvicidal activity against Culex pipiens. Crude extracts (CEs) were prepared using ethanol, ethyl acetate and n-hexane. CEs have been used for assessment of mosquitocidal bioassay. The metabolomic analyses for CEs were characterized for each CE by gas chromatography-mass spectrometry (GC-MS). The most efficient CE with the highest larval mortality and the least LC50 was the hexane CE. Then, alkaline phosphatase (ALP) activity, and glutathione-S-transferase (GST) activity were assessed in larvae treated with the hexane CE. The results demonstrated a decline in protein content, induction of ALP activity, and reduction in GST activity. Finally, molecular docking and dynamic simulation techniques were employed to evaluate the interaction between the hexane phytochemicals and the GST protein. D-(+)-Glucuronic acid, 3TMS derivative and Sebacic acid, 2TMS derivative showed best binding affinities to GST protein pointing to their interference with the enzyme detoxification functions, potentially leading to reduced ability to metabolize insecticides.


Assuntos
Glutationa Transferase , Larva , Metabolômica , Simulação de Acoplamento Molecular , Compostos Fitoquímicos , Extratos Vegetais , Glutationa Transferase/metabolismo , Animais , Metabolômica/métodos , Compostos Fitoquímicos/farmacologia , Compostos Fitoquímicos/química , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Larva/efeitos dos fármacos , Controle de Mosquitos/métodos , Culex/efeitos dos fármacos , Culex/enzimologia , Inseticidas/química , Inseticidas/farmacologia , Metaboloma/efeitos dos fármacos
11.
Mar Drugs ; 22(6)2024 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-38921593

RESUMO

Four new cyclic pentapeptides, avellanins D-G (1-4), together with four known compounds (5-8), were isolated from a mangrove-derived Aspergillus fumigatus GXIMD 03099 fungus from Acanthus ilicifolius L. Their structures were elucidated by analysis of HRESIMS, NMR, and ESI-MS/MS data. Their absolute configurations were determined by X-ray diffraction analysis and Marfey's method. Compounds 1-8 were screened for insecticidal and antibacterial activities. Compound 2 showed insecticidal activity against newly hatched larvae of Culex quinquefasciatus with an LC50 value of 86.6 µM; compound 4 had weak activity against Vibrio harveyi with an MIC value of 5.85 µM.


Assuntos
Antibacterianos , Aspergillus fumigatus , Inseticidas , Testes de Sensibilidade Microbiana , Peptídeos Cíclicos , Aspergillus fumigatus/efeitos dos fármacos , Peptídeos Cíclicos/farmacologia , Peptídeos Cíclicos/química , Peptídeos Cíclicos/isolamento & purificação , Animais , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Inseticidas/farmacologia , Inseticidas/química , Inseticidas/isolamento & purificação , Vibrio/efeitos dos fármacos , Culex/efeitos dos fármacos , Larva/efeitos dos fármacos , Estrutura Molecular
12.
J Vector Borne Dis ; 61(2): 227-235, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38922657

RESUMO

BACKGROUND OBJECTIVES: Aedes aegypti and Ae. albopictus mosquitoes breed in natural and artificial containers, and they transmit dengue and chikungunya. A study was conducted to identify the contribution of bamboo stumps to these disease vectors that were used in the flower garden as pillars to hold the bamboo flex fence. METHODS: Two sizes of whole bamboo were used to hold fences around gardens at Dhaka University, Bangladesh, and were painted red and green. Mosquito larvae and pupae were collected from bamboo stumps between July and August, and vectors were identified up to the species level. The data were analyzed using the STATA/MP 14.2 version. RESULTS: 83.5% and 0.2% were Ae. albopictus and Ae. aegypti, respectively, and the remaining were Culex and Ar-migeres species. Ae. albopictus, Ae. aegypti, and both species-positive bamboo stumps were 46.9, 0.7, and 47.1%, respectively. 54.5% of the bamboo stumps had at least one mosquito species. The average stump depth for Aedes positive stumps (mean=11.7 cm, SE = 0.5) was significantly (p <0.001) higher than the Aedes negative stumps (mean = 9.5 cm, SE = 0.4). 53.8% and 38.0% stumps were found Aedes positive on the ground and upper sides of fences, respectively, and found significant (p<0.01) differences between both sides. A zero-inflated negative binomial count model is significant at a 5% level of significance, χ2(4) = 11.8, p = 0.019 (<0.05) for Ae. albopictus. Stump depth is found to have a significant positive effect on the number of Aedes-positive stumps. INTERPRETATION CONCLUSION: Artificially used natural containers are adding pressure to current mosquito control activities as mosquitoes are breeding on them, which needs additional attention.


Assuntos
Aedes , Febre de Chikungunya , Dengue , Larva , Controle de Mosquitos , Mosquitos Vetores , Animais , Bangladesh/epidemiologia , Dengue/transmissão , Dengue/prevenção & controle , Aedes/fisiologia , Aedes/virologia , Controle de Mosquitos/métodos , Mosquitos Vetores/fisiologia , Mosquitos Vetores/virologia , Febre de Chikungunya/transmissão , Febre de Chikungunya/prevenção & controle , Larva/fisiologia , Pupa/fisiologia , Sasa , Culex/fisiologia , Humanos
13.
Parasit Vectors ; 17(1): 201, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38711091

RESUMO

PURPOSE: The rising burden of mosquito-borne diseases in Europe extends beyond urban areas, encompassing rural and semi-urban regions near managed and natural wetlands evidenced by recent outbreaks of Usutu and West Nile viruses. While wetland management policies focus on biodiversity and ecosystem services, few studies explore the impact on mosquito vectors. METHODS: Our research addresses this gap, examining juvenile mosquito and aquatic predator communities in 67 ditch sites within a South England coastal marsh subjected to different wetland management tiers. Using joint distribution models, we analyse how mosquito communities respond to abiotic and biotic factors influenced by wetland management. RESULTS: Of the 12 mosquito species identified, Culiseta annulata (Usutu virus vector) and Culex pipiens (Usutu and West Nile virus vector) constitute 47% of 6825 larval mosquitoes. Abundant predators include Coleoptera (water beetles) adults, Corixidae (water boatmen) and Zygoptera (Damselfy) larvae. Models reveal that tier 3 management sites (higher winter water levels, lower agricultural intensity) associated with shade and less floating vegetation are preferred by specific mosquito species. All mosquito species except Anopheles maculipennis s.l., are negatively impacted by potential predators. Culiseta annulata shows positive associations with shaded and turbid water, contrary to preferences of Corixidae predators. CONCLUSIONS: Tier 3 areas managed for biodiversity, characterised by higher seasonal water levels and reduced livestock grazing intensity, provide favourable habitats for key mosquito species that are known vectors of arboviruses, such as Usutu and West Nile. Our findings emphasise the impact of biodiversity-focused wetland management, altering mosquito breeding site vegetation to enhance vector suitability. Further exploration of these trade-offs is crucial for comprehending the broader implications of wetland management.


Assuntos
Biodiversidade , Culicidae , Mosquitos Vetores , Áreas Alagadas , Animais , Mosquitos Vetores/fisiologia , Mosquitos Vetores/virologia , Culicidae/classificação , Culicidae/fisiologia , Culicidae/virologia , Ecossistema , Larva/fisiologia , Estações do Ano , Reino Unido , Culex/fisiologia , Culex/virologia , Culex/classificação , Inglaterra
14.
Parasit Vectors ; 17(1): 200, 2024 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-38704595

RESUMO

BACKGROUND: Mayaro virus (MAYV) is an emerging alphavirus, primarily transmitted by the mosquito Haemagogus janthinomys in Central and South America. However, recent studies have shown that Aedes aegypti, Aedes albopictus and various Anopheles mosquitoes can also transmit the virus under laboratory conditions. MAYV causes sporadic outbreaks across the South American region, particularly in areas near forests. Recently, cases have been reported in European and North American travelers returning from endemic areas, raising concerns about potential introductions into new regions. This study aims to assess the vector competence of three potential vectors for MAYV present in Europe. METHODS: Aedes albopictus from Italy, Anopheles atroparvus from Spain and Culex pipiens biotype molestus from Belgium were exposed to MAYV and maintained under controlled environmental conditions. Saliva was collected through a salivation assay at 7 and 14 days post-infection (dpi), followed by vector dissection. Viral titers were determined using focus forming assays, and infection rates, dissemination rates, and transmission efficiency were calculated. RESULTS: Results indicate that Ae. albopictus and An. atroparvus from Italy and Spain, respectively, are competent vectors for MAYV, with transmission possible starting from 7 dpi under laboratory conditions. In contrast, Cx. pipiens bioform molestus was unable to support MAYV infection, indicating its inability to contribute to the transmission cycle. CONCLUSIONS: In the event of accidental MAYV introduction in European territories, autochthonous outbreaks could potentially be sustained by two European species: Ae. albopictus and An. atroparvus. Entomological surveillance should also consider certain Anopheles species when monitoring MAYV transmission.


Assuntos
Aedes , Infecções por Alphavirus , Alphavirus , Culex , Mosquitos Vetores , Animais , Aedes/virologia , Mosquitos Vetores/virologia , Alphavirus/fisiologia , Alphavirus/isolamento & purificação , Culex/virologia , Europa (Continente) , Infecções por Alphavirus/transmissão , Infecções por Alphavirus/virologia , Saliva/virologia , Anopheles/virologia , Espanha , Itália , Feminino , Bélgica
15.
Parasit Vectors ; 17(1): 204, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38715075

RESUMO

BACKGROUND: Mosquito-borne viruses cause various infectious diseases in humans and animals. Oya virus (OYAV) and Ebinur Lake virus (EBIV), belonging to the genus Orthobunyavirus within the family Peribunyaviridae, are recognized as neglected viruses with the potential to pose threats to animal or public health. The evaluation of vector competence is essential for predicting the arbovirus transmission risk. METHODS: To investigate the range of mosquito vectors for OYAV (strain SZC50) and EBIV (strain Cu20-XJ), the susceptibility of four mosquito species (Culex pipiens pallens, Cx. quinquefasciatus, Aedes albopictus, and Ae. aegypti) was measured through artificial oral infection. Then, mosquito species with a high infection rate (IR) were chosen to further evaluate the dissemination rate (DR), transmission rate (TR), and transmission efficiency. The viral RNA in each mosquito sample was determined by RT-qPCR. RESULTS: The results revealed that for OYAV, Cx. pipiens pallens had the highest IR (up to 40.0%) among the four species, but the DR and TR were 4.8% and 0.0%, respectively. For EBIV, Cx. pipiens pallens and Cx. quinquefasciatus had higher IR compared to Ae. albopictus (1.7%). However, the EBIV RNA and infectious virus were detected in Cx. pipiens pallens, with a TR of up to 15.4% and a transmission efficiency of 3.3%. CONCLUSIONS: The findings indicate that Cx. pipiens pallens was susceptible to OYAV but had an extremely low risk of transmitting the virus. Culex pipiens pallens and Cx. quinquefasciatus were susceptible to EBIV, and Cx. pipiens pallens had a higher transmission risk to EBIV than Cx. quinquefasciatus.


Assuntos
Aedes , Culex , Mosquitos Vetores , Orthobunyavirus , Animais , Mosquitos Vetores/virologia , Aedes/virologia , Culex/virologia , Orthobunyavirus/genética , Orthobunyavirus/classificação , Orthobunyavirus/isolamento & purificação , RNA Viral/genética , Infecções por Bunyaviridae/transmissão , Infecções por Bunyaviridae/virologia
16.
Sci Data ; 11(1): 471, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38724521

RESUMO

We present a de novo transcriptome of the mosquito vector Culex pipiens, assembled by sequences of susceptible and insecticide resistant larvae. The high quality of the assembly was confirmed by TransRate and BUSCO. A mapping percentage until 94.8% was obtained by aligning contigs to Nr, SwissProt, and TrEMBL, with 27,281 sequences that simultaneously mapped on the three databases. A total of 14,966 ORFs were also functionally annotated by using the eggNOG database. Among them, we identified ORF sequences of the main gene families involved in insecticide resistance. Therefore, this resource stands as a valuable reference for further studies of differential gene expression as well as to identify genes of interest for genetic-based control tools.


Assuntos
Culex , Resistência a Inseticidas , Larva , Transcriptoma , Animais , Culex/genética , Larva/genética , Larva/crescimento & desenvolvimento , Resistência a Inseticidas/genética , Mosquitos Vetores/genética , Fases de Leitura Aberta
17.
Acta Trop ; 256: 107260, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38782110

RESUMO

Avian haemosporidian parasites are spread worldwide and pose a threat to their hosts occasionally. A complete life cycle of these parasites requires two hosts: vertebrate and invertebrate (a blood-sucking insect that acts as a vector). In this study, we tested wild-caught mosquitoes for haemosporidian infections. Mosquitoes were collected (2021-2023) in several localities in Lithuania using a sweeping net and a CDC trap baited with CO2, morphologically identified, and preparations of salivary glands were prepared (from females collected in 2022-2023). 2093 DNA samples from either individual after dissection (1675) or pools (418 pools/1145 individuals) of female mosquito's abdomens were screened using PCR for the detection of haemosporidian parasite DNA. Salivary gland preparations were analyzed microscopically from each PCR-positive mosquito caught in 2022 and 2023. The average prevalence of haemosporidian parasites for all analyzed samples was 2.0 % and varied between 0.6 % (2021) and 3.5 % (2022). DNA of Plasmodium ashfordi (cytochrome b genetic lineage pGRW02), P. circumflexum (pTURDUS1), P. homonucleophilum (pSW2), P. matutinum (pLINN1), P. vaughani (pSYAT05), Haemoproteus brachiatus (hLK03), H. majoris (hWW2), and H. minutus (hTUPHI01) were detected in mosquitoes. Coquilletidia richiardii (3.5 %) and Culex pipiens (2.9 %) were mosquito species with the highest prevalence of haemosporidian parasite DNA detected. Mixed infections were detected in 16 mosquitoes. In one of the samples, sporozoites of P. matutinum (pLINN1) were found in the salivary gland preparation of Culex pipiens, confirming this mosquito species as a competent vector of Plasmodium matutinum and adding it to the list of the natural vectors of this avian parasite.


Assuntos
Mosquitos Vetores , Plasmodium , Glândulas Salivares , Animais , Feminino , Mosquitos Vetores/parasitologia , Plasmodium/isolamento & purificação , Plasmodium/genética , Plasmodium/classificação , Glândulas Salivares/parasitologia , Lituânia , Haemosporida/genética , Haemosporida/isolamento & purificação , Haemosporida/classificação , Culicidae/parasitologia , Aves/parasitologia , Reação em Cadeia da Polimerase , Culex/parasitologia , DNA de Protozoário/genética
18.
Acta Trop ; 256: 107269, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38821147

RESUMO

Mosquitoes serve as vectors for various diseases like malaria, dengue fever, yellow fever, and lymphatic filarial diseases causing significant global health problems, highlighting the importance of vector control. The study was conducted to assess the effectiveness of nanoformulated clothianidin and chlorfenapyr insecticides treated with ATSB in controlling three mosquito strains. The development of a natural thiolated polymer-coated ATSB nano formulation involved incorporating nano-carriers to deliver insecticides. Field- collected mosquito strains were subjected to laboratory-based bioassays using 1 % and 1.5 % concentrations of each conventionally used and nanoformulated insecticide with ATSB solution. Adult mosquitoes were left overnight to contact with N-ATSB and efficacy was recorded after 36 and 72 h. The results showed that nanoformulated chlorfenapyr was significantly more effective as compared to clothianidin against An. funestus and Cx. quinquefasciatus but the results were not significantly different against An. coluzzii (100 %). An. coluzzii was found to be the most susceptible strain followed by An. funestus and showed 100 % and ∼ 98 % mortality against nanoformulated chlorfenapyr (1.5 %). Nanoformulated clothianidin induced more than 92 % and ∼ 100 % mortality against An. funestus and An. coluzzii respectively. However, Cx. quinquefasciatus significantly showed less mortality against nanoformulated clothianidin (88 %) and chlorfenapyr (>95 %) as compared to Anopheline strains. Furthermore, results indicate that nanoformulated insecticides significantly caused greater and prolonged fatality as compared to conventional form, suggesting effective and suitable strategies for vector management.


Assuntos
Anopheles , Culex , Guanidinas , Inseticidas , Controle de Mosquitos , Neonicotinoides , Piretrinas , Tiazóis , Animais , Guanidinas/química , Guanidinas/farmacologia , Inseticidas/farmacologia , Culex/efeitos dos fármacos , Neonicotinoides/farmacologia , Anopheles/efeitos dos fármacos , Controle de Mosquitos/métodos , Piretrinas/farmacologia , Feminino , Análise de Sobrevida , Bioensaio
19.
Acta Trop ; 256: 107276, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38821146

RESUMO

Culex gelidus (Diptera: Culicidae), an important vector of the Japanese encephalitis virus (JEV), contributes to human viral encephalitis in many Asian countries, including Thailand. This study represents the first investigation of the demographic patterns of Cx. gelidus populations in Thailand using cytochrome c oxidase subunit I (COI) gene analysis and wing geometric morphometrics (GM). Mosquitoes were collected from 10 provinces across six regions of Thailand in 2022. Analysis of the COI sequences (n = 182) indicated high haplotype diversity (0.882) and low nucleotide diversity (0.006), with 72 haplotypes identified. The haplotype network demonstrated no profound splits among the geographic populations. Neutral tests, including Tajima's D and Fu's Fs, displayed negative values, with a significant result observed for Fu's Fs (-33.048, p < 0.05). The mismatch distribution analysis indicated that the population does not statistically deviate from a model of sudden population expansion (SSD = 0.010, p > 0.05; Rg = 0.022, p > 0.05). The estimations suggest that the Cx. gelidus population in Thailand began its expansion approximately between 459,243 and 707,011 years ago. The Mantel test showed no significant relationship between genetic and geographic distances (r = 0.048, p > 0.05). Significant phenotypic differences (based on wing shape) were observed among most populations. Additionally, in this study, we found no significant relationships between phenotypic and genetic distances (r = 0.250, p > 0.05). Understanding the genetic and morphological dynamics of Cx. gelidus is vital for developing targeted surveillance and vector control measures. This knowledge will also help to predict how future environmental changes might affect these populations, thereby informing long-term vector management strategies.


Assuntos
Culex , Complexo IV da Cadeia de Transporte de Elétrons , Mosquitos Vetores , Asas de Animais , Animais , Tailândia , Culex/genética , Culex/virologia , Culex/anatomia & histologia , Complexo IV da Cadeia de Transporte de Elétrons/genética , Mosquitos Vetores/genética , Mosquitos Vetores/anatomia & histologia , Mosquitos Vetores/virologia , Asas de Animais/anatomia & histologia , DNA Mitocondrial/genética , Variação Genética , Haplótipos , Feminino , Encefalite Japonesa/virologia , Vírus da Encefalite Japonesa (Espécie)/genética , Masculino , Filogenia
20.
Parasit Vectors ; 17(1): 222, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38745242

RESUMO

BACKGROUND: Culex pipiens pallens is a well-known mosquito vector for several diseases. Deltamethrin, a commonly used pyrethroid insecticide, has been frequently applied to manage adult Cx. pipiens pallens. However, mosquitoes can develop resistance to these insecticides as a result of insecticide misuse and, therefore, it is crucial to identify novel methods to control insecticide resistance. The relationship between commensal bacteria and vector resistance has been recently recognized. Bacteriophages (= phages) are effective tools by which to control insect commensal bacteria, but there have as yet been no studies using phages on adult mosquitoes. In this study, we isolated an Aeromonas phage vB AhM-LH that specifically targets resistance-associated symbiotic bacteria in mosquitoes. We investigated the impact of Aeromonas phage vB AhM-LH in an abundance of Aeromonas hydrophila in the gut of Cx. pipiens pallens and its effect on the status of deltamethrin resistance. METHODS: Phages were isolated on double-layer agar plates and their biological properties analyzed. Phage morphology was observed by transmission electron microscopy (TEM) after negative staining. The phage was then introduced into the mosquito intestines via oral feeding. The inhibitory effect of Aeromonas phage vB AhM-LH on Aeromonas hydrophila in mosquito intestines was assessed through quantitative real-time PCR analysis. Deltamethrin resistance of mosquitoes was assessed using WHO bottle bioassays. RESULTS: An Aeromonas phage vB AhM-LH was isolated from sewage and identified as belonging to the Myoviridae family in the order Caudovirales using TEM. Based on biological characteristics analysis and in vitro antibacterial experiments, Aeromonas phage vB AhM-LH was observed to exhibit excellent stability and effective bactericidal activity. Sequencing revealed that the Aeromonas phage vB AhM-LH genome comprises 43,663 bp (51.6% CG content) with 81 predicted open reading frames. No integrase-related gene was detected in the vB AH-LH genome, which marked it as a potential biological antibacterial. Finally, we found that Aeromonas phage vB AhM-LH could significantly reduce deltamethrin resistance in Cx. pipiens pallens, in both the laboratory and field settings, by decreasing the abundance of Aeromonas hydrophila in their midgut. CONCLUSIONS: Our findings demonstrate that Aeromonas phage vB AhM-LH could effectively modulate commensal bacteria Aeromonas hydrophila in adult mosquitoes, thus representing a promising strategy to mitigate mosquito vector resistance.


Assuntos
Aeromonas hydrophila , Bacteriófagos , Culex , Resistência a Inseticidas , Nitrilas , Piretrinas , Animais , Aeromonas hydrophila/virologia , Aeromonas hydrophila/efeitos dos fármacos , Culex/virologia , Culex/microbiologia , Bacteriófagos/fisiologia , Bacteriófagos/isolamento & purificação , Bacteriófagos/genética , Piretrinas/farmacologia , Nitrilas/farmacologia , Inseticidas/farmacologia , Mosquitos Vetores/virologia , Mosquitos Vetores/microbiologia , Feminino
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