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1.
Braz. j. biol ; 83: e247604, 2023. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1339370

RESUMO

Abstract In the current report, we studied the possible inhibitors of COVID-19 from bioactive constituents of Centaurea jacea using a threefold approach consisting of quantum chemical, molecular docking and molecular dynamic techniques. Centaurea jacea is a perennial herb often used in folk medicines of dermatological complaints and fever. Moreover, anticancer, antioxidant, antibacterial and antiviral properties of its bioactive compounds are also reported. The Mpro (Main proteases) was docked with different compounds of Centaurea jacea through molecular docking. All the studied compounds including apigenin, axillarin, Centaureidin, Cirsiliol, Eupatorin and Isokaempferide, show suitable binding affinities to the binding site of SARS-CoV-2 main protease with their binding energies -6.7 kcal/mol, -7.4 kcal/mol, -7.0 kcal/mol, -5.8 kcal/mol, -6.2 kcal/mol and -6.8 kcal/mol, respectively. Among all studied compounds, axillarin was found to have maximum inhibitor efficiency followed by Centaureidin, Isokaempferide, Apigenin, Eupatorin and Cirsiliol. Our results suggested that axillarin binds with the most crucial catalytic residues CYS145 and HIS41 of the Mpro, moreover axillarin shows 5 hydrogen bond interactions and 5 hydrophobic interactions with various residues of Mpro. Furthermore, the molecular dynamic calculations over 60 ns (6×106 femtosecond) time scale also shown significant insights into the binding effects of axillarin with Mpro of SARS-CoV-2 by imitating protein like aqueous environment. From molecular dynamic calculations, the RMSD and RMSF computations indicate the stability and dynamics of the best docked complex in aqueous environment. The ADME properties and toxicity prediction analysis of axillarin also recommended it as safe drug candidate. Further, in vivo and in vitro investigations are essential to ensure the anti SARS-CoV-2 activity of all bioactive compounds particularly axillarin to encourage preventive use of Centaurea jacea against COVID-19 infections.


Resumo No presente relatório, estudamos os possíveis inibidores de Covid-19 de constituintes bioativos de Centaurea jacea usando uma abordagem tripla que consiste em técnicas de química quântica, docking molecular e dinâmica molecular. Centaurea jacea é uma erva perene frequentemente usada em remédios populares de doenças dermatológicas e febre. Além disso, as propriedades anticâncer, antioxidante, antibacteriana e antiviral de seus compostos bioativos também são relatadas. A Mpro (proteases principais) foi acoplada a diferentes compostos de Centaurea jacea por meio de docking molecular. Todos os compostos estudados, incluindo apigenina, axilarina, Centaureidina, Cirsiliol, Eupatorina e Isokaempferide, mostram afinidades de ligação adequadas ao sítio de ligação da protease principal SARS-CoV-2 com suas energias de ligação -6,7 kcal / mol, -7,4 kcal / mol, - 7,0 kcal / mol, -5,8 kcal / mol, -6,2 kcal / mol e -6,8 kcal / mol, respectivamente. Dentre todos os compostos estudados, a axilarina apresentou eficiência máxima de inibidor, seguida pela Centaureidina, Isokaempferida, Apigenina, Eupatorina e Cirsiliol. Nossos resultados sugeriram que a axilarina se liga aos resíduos catalíticos mais cruciais CYS145 e HIS41 do Mpro, além disso a axilarina mostra 5 interações de ligações de hidrogênio e 5 interações hidrofóbicas com vários resíduos de Mpro. Além disso, os cálculos de dinâmica molecular em uma escala de tempo de 60 ns (6 × 106 femtossegundos) também mostraram percepções significativas sobre os efeitos de ligação da axilarina com Mpro de SARS-CoV-2 por imitação de proteínas como o ambiente aquoso. A partir de cálculos de dinâmica molecular, os cálculos RMSD e RMSF indicam a estabilidade e dinâmica do melhor complexo ancorado em ambiente aquoso. As propriedades ADME e a análise de previsão de toxicidade da axilarina também a recomendaram como um candidato a medicamento seguro. Além disso, as investigações in vivo e in vitro são essenciais para garantir a atividade anti-SARS-CoV-2 de todos os compostos bioativos, particularmente a axilarina, para encorajar o uso preventivo de Centaurea jacea contra infecções por Covid-19.


Assuntos
Humanos , Preparações Farmacêuticas , Centaurea , COVID-19 , Inibidores de Proteases , Simulação de Dinâmica Molecular , Simulação de Acoplamento Molecular , SARS-CoV-2
2.
Braz. j. biol ; 83: e246230, 2023. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1339369

RESUMO

Abstract Dengue fever vectored by the mosquito Aedes aegypti is one of the most rapidly spreading insect-borne diseases. Current reliance of dengue vector control is mostly on chemical insecticides. Growing insecticide resistance in the primary mosquito vector, Aedes aegypti, limits the effectiveness of vector control through chemical insecticides. These chemical insecticides also have negative environmental impacts on animals, plants and human health. Myco-biocontrol agents are naturally occurring organisms and are found to be less damaging to the environment as compared to chemical insecticides. In the present study, entomopathogenic potential of local strains of fungi isolated from soil was assessed for the control of dengue vector. Local fungal isolates presents better alternative to introducing a foreign biocontrol strain, as they may be better adapted to environmental conditions of the area to survive and may have more entomopathogenic efficacy against target organism. Larvicidal efficacy of Fusarium equiseti and Fusarium proliferatum was evaluated against Aedes aegypti. Local strains of F. equiseti (MK371718) and F. proliferatum (MK371715) were isolated from the soil of Changa Manga Forest, Pakistan by using insect bait method. Larvicidal activity of two Fusarium spp. was tested against forth instar larvae of A. aegypti in the laboratory, using concentrations 105, 106, 107 and 108 conidia /ml. LC50 values for F. equiseti after 24h, 48h, 72h and 96h of exposure were recorded as 3.8x 108, 2.9x107, 2.0x107, and 7.1x106 conidia /ml respectively while LC50 values for F. proliferatum were recorded as 1.21x108, 9.6x107, 4.2x107, 2.6x107 conidia /ml respectively after 24h, 48h, 72h and 96h of exposure. The results indicate that among two fungal strains F. equiseti was found to be more effective in terms of its larvicidal activity than F. proliferatum against larvae of A. aegypti.


Resumo A dengue transmitida pelo mosquito Aedes aegypti é uma das doenças transmitidas por insetos de propagação mais rápida. A dependência atual do controle do vetor da dengue é principalmente de inseticidas químicos. O aumento da resistência a inseticidas no principal vetor do mosquito, Aedes aegypti, limita a eficácia do controle do vetor por meio de inseticidas químicos. Esses inseticidas químicos também têm impactos ambientais negativos sobre os animais, plantas e saúde humana. Os agentes de micobiocontrole são organismos que ocorrem naturalmente e são menos prejudiciais ao meio ambiente em comparação com os inseticidas químicos. No presente estudo, avaliou-se o potencial entomopatogênico de cepas locais de fungos isolados do solo para o controle do vetor da dengue. Isolados de fungos locais apresentam melhor alternativa para a introdução de uma cepa de biocontrole estrangeira, pois podem ser mais bem adaptados às condições ambientais da área para sobreviver e podem ter maior eficácia entomopatogênica contra o organismo-alvo. A eficácia larvicida de Fusarium equiseti e Fusarium proliferatum foi avaliada contra Aedes aegypti. Cepas locais de F. equiseti (MK371718) e F. proliferatum (MK371715) foram isoladas do solo de Changa Manga Forest, Paquistão, usando o método de isca para insetos. Atividade larvicida de dois Fusarium spp. foi testado contra larvas de quarto ínstar de A. aegypti em laboratório, nas concentrações 105, 106, 107 e 108 conídios / ml. Os valores de LC50 para F. equiseti após 24 h, 48 h, 72 h e 96 h de exposição foram registrados como 3,8x 108, 2,9x107, 2,0x107 e 7,1x106 conídios / ml, respectivamente, enquanto os valores de LC50 para F. proliferatum foram registrados como 1,21x108, 9,6 x107, 4,2x107, 2,6x107 conídios / ml, respectivamente, após 24 h, 48 h, 72 h e 96 h de exposição. Os resultados indicam que entre duas cepas de fungos F. equiseti se mostrou mais eficaz em termos de atividade larvicida do que F. proliferatum contra larvas de A. aegypti.


Assuntos
Humanos , Animais , Aedes , Fusarium , Inseticidas/farmacologia , Paquistão , Solo , Extratos Vegetais , Florestas , Mosquitos Vetores , Larva
3.
Braz. j. biol ; 83: e247539, 2023. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1278542

RESUMO

Abstract Numerous studies have investigated the chemical composition and biological activities of essential oils from different Citrus species fruit peel, leaves and flowers. This paper aims to investigate the chemical composition, larvicidal and antileishmanial activities of essential oil from Citrus reticulata fruit peel (CR-EO). CR-EO was obtained by hydrodistillation in a Clevenger-type apparatus and its chemical composition was analyzed by GC-MS and GC-FID. Limonene (85.7%), ɣ-terpinene (6.7%) and myrcene (2.1%) were identified as its major components. CR-EO showed high activity against promastigote forms of Leishmania amazonensis (IC50 = 8.23 µg/mL). CR-EO also exhibited high larvicidal activity against third instar Aedes aegypti larvae at a lethal concentration (LC50 = 58.35 µg/mL) and 100% mortality at 150 µg/mL. This study suggests, for the first time, the potential use of CR-EO against this important mosquito-borne viral disease caused by the genus Aedes.


Resumo Numerosos estudos têm investigado a composição química e as atividades biológicas de óleos essenciais extraídos de cascas dos frutos, folhas e flores de diferentes espécies de Citrus. Este trabalho tem como objetivo investigar a composição química e as atividades larvicida e leishmanicida in vitro do óleo essencial das cascas dos frutos de Citrus reticulata (CR-EO). CR-EO foi obtido pela técnica de extração em aparelho Clevenger e sua composição química foi determinada por CG-EM e CG-DIC. Limoneno (85,7%), ɣ-terpineno (6,7%) and mirceno (2,1%) foram identificados como os constituintes majoritários. CR-EO mostrou alta atividade contra as formas promastigota de Leishmania amazonensis (CI50 = 8,23 µg/mL). CR-EO também exibiu alta atividade larvicida contra as larvas do terceiro estágio do Aedes aegypti com concentração letal (CL50 = 58,35 µg/mL) e mortalidade de 100% em 150 µg/mL. Este estudo sugere, pela primeira vez, o uso potencial de CR-EO contra esta importante doença viral transmitida por mosquitos do gênero Aedes.


Assuntos
Animais , Óleos Voláteis/farmacologia , Citrus , Aedes , Inseticidas/farmacologia , Frutas , Larva
4.
Braz. j. biol ; 83: e244647, 2023. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1278527

RESUMO

Abstract The essential oil of citronella (Cymbopogon winterianus) has several biological activities, among them the insect repellent action. Some studies showed that cinnamic acid esters can be applied as natural pesticides, insecticides and fungicides. In this context, the objective of the present work was to evaluate the production of esters from citronella essential oil with cinnamic acid via enzymatic esterification. Besides, the essential oil toxicity before and after esterification against Artemia salina and larvicidal action on Aedes aegypti was investigated. Esters were produced using cinnamic acid as the acylating agent and citronella essential oil (3:1) in heptane and 15 wt% NS 88011 enzyme as biocatalysts, at 70 °C and 150 rpm. Conversion rates of citronellyl and geranyl cinnamates were 58.7 and 69.0% for NS 88011, respectively. For the toxicity to Artemia salina LC50 results of 5.29 μg mL-1 were obtained for the essential oil and 4.36 μg mL-1 for the esterified oils obtained with NS 88011. In the insecticidal activity against Aedes aegypti larvae, was obtained LC50 of 111.84 μg mL-1 for the essential oil of citronella and 86.30 μg mL-1 for the esterified oils obtained with the enzyme NS 88011, indicating high toxicity of the esters. The results demonstrated that the evaluated samples present potential of application as bioinsecticide.


Resumo O óleo essencial de citronela (Cymbopogon winterianus) possui diversas atividades biológicas, entre elas a ação repelente a insetos. Alguns estudos mostraram que os ésteres do ácido cinâmico podem ser aplicados como pesticidas naturais, inseticidas e fungicidas. Nesse contexto, o objetivo do presente trabalho foi avaliar a produção de ésteres a partir do óleo essencial de citronela com ácido cinâmico via esterificação enzimática. Além disso, foi investigada a toxicidade do óleo essencial antes e após a esterificação contra Artemia salina e a ação larvicida sobre Aedes aegypti. Os ésteres foram produzidos utilizando ácido cinâmico como agente acilante e óleo essencial de citronela (3: 1) em heptano e 15% em peso da enzima NS 88011 como biocatalisadores, a 70 ° C e 150 rpm. As taxas de conversão de cinamatos de citronelil e geranil foram 58,7 e 69,0% para NS 88011, respectivamente. Para a toxicidade sobre Artemia salina foram obtidos CL50 de 5,29 μg mL-1 para o óleo essencial e 4,36 μg mL-1 para os óleos esterificados com NS 88011. Na atividade inseticida contra larvas de Aedes aegypti, obteve-se CL50 de 111,84 μg mL-1 para o óleo essencial de citronela e 86,30 μg mL-1 para os óleos esterificados com a enzima NS 88011, indicando alta toxicidade dos ésteres. Os resultados demonstraram que as amostras avaliadas apresentam potencial de aplicação como bioinseticida.


Assuntos
Animais , Óleos Voláteis/toxicidade , Aedes , Cymbopogon , Repelentes de Insetos , Inseticidas/toxicidade , Esterificação , Larva
5.
PLoS One ; 17(8): e0269880, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35913994

RESUMO

BACKGROUND: The mosquito Aedes koreicus (Edwards, 1917) is a recent invader on the European continent that was introduced to several new places since its first detection in 2008. Compared to other exotic Aedes mosquitoes with public health significance that invaded Europe during the last decades, this species' biology, behavior, and dispersal patterns were poorly investigated to date. METHODOLOGY/PRINCIPAL FINDINGS: To understand the species' population relationships and dispersal patterns within Europe, a fragment of the cytochrome oxidase I (COI or COX1) gene was sequenced from 130 mosquitoes, collected from five countries where the species has been introduced and/or established. Oxford Nanopore and Illumina sequencing techniques were combined to generate the first complete nuclear and mitochondrial genomic sequences of Ae. koreicus from the European region. The complete genome of Ae. koreicus is 879 Mb. COI haplotype analyses identified five major groups (altogether 31 different haplotypes) and revealed a large-scale dispersal pattern between European Ae. koreicus populations. Continuous admixture of populations from Belgium, Italy, and Hungary was highlighted, additionally, haplotype diversity and clustering indicate a separation of German sequences from other populations, pointing to an independent introduction of Ae. koreicus to Europe. Finally, a genetic expansion signal was identified, suggesting the species might be present in more locations than currently detected. CONCLUSIONS/SIGNIFICANCE: Our results highlight the importance of genetic research of invasive mosquitoes to understand general dispersal patterns, reveal main dispersal routes and form the baseline of future mitigation actions. The first complete genomic sequence also provides a significant leap in the general understanding of this species, opening the possibility for future genome-related studies, such as the detection of 'Single Nucleotide Polymorphism' markers. Considering its public health importance, it is crucial to further investigate the species' population genetic dynamic, including a larger sampling and additional genomic markers.


Assuntos
Aedes , Aedes/genética , Animais , Vetores de Doenças , Europa (Continente) , Variação Genética , Espécies Introduzidas , Mosquitos Vetores/genética
6.
Brasilia, D.F.; OPAS; 2022-08-03. (OPAS-W/BRA/FGL/COVID-19/22-0023).
Não convencional em Português | PAHO-IRIS | ID: phr2-56214

RESUMO

Depois de mais de 22 meses da pandemia de COVID-19 em curso na Região das Américas, onde casos e mortes por COVID-19 foram relatados em todos os 56 países e territórios na Região das Américas, os sistemas de saúde ainda estão sendo desafiados e as atividades de imunização rotineira ainda estão atrasadas na maioria dos países. A pandemia afetou o cumprimento dos indicadores de vigilância de doenças preveníveis por vacinação (VPD, sigla em inglês). Além disso, as restrições impostas ao movimento e as preocupações com a pandemia limitaram as atividades da atenção primária à saúde, incluindo serviços preventivos como a vacinação, com a consequente queda na cobertura vacinal e aumento da população suscetível.


Assuntos
Doenças Preveníveis por Vacina , Imunização , Vacinas , Difteria , Sarampo , Vacina contra Sarampo , Febre Amarela , Vacina contra Febre Amarela , Poliomielite , COVID-19 , América
7.
BMC Infect Dis ; 22(1): 682, 2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-35945491

RESUMO

BACKGROUND: Immunization against the coronavirus disease 2019 (COVID-19) began in January 2021 in Iran; nonetheless, due to a lack of vaccination among children under 12, this age group is still at risk of SARS-CoV-2 infection and its complications. CASE PRESENTATION: SARS-CoV-2 infection was diagnosed in a 6-year-old girl who had previously been healthy but had developed a fever and pancytopenia. The bone marrow aspiration/biopsy demonstrated just hypocellular marrow without signs of leukemia. She was worked up for primary and secondary causes of pancytopenia. Except for a repeated reactive HIV antibody/Ag P24 assay, all test results were inconclusive. After a thorough diagnostic investigation, the cross-reactivity of the HIV antibody/Ag P24 test with SARS-CoV-2 antibodies was confirmed. The patient did not develop any COVID-19-related signs and symptoms, but she did get a severe invasive fungal infection and neutropenic enterocolitis. She died as a result of disseminated intravascular coagulopathy. CONCLUSION: It is critical to recognize children infected with SARS-CoV-2 who exhibit atypical clinical manifestations of COVID-19, such as persistent pancytopenia. SARS-CoV-2 infection can cause severe and deadly consequences in children; thus, pediatricians should be aware of COVID-19's unusual signs and symptoms mimicking other conditions such as aplastic anemia.


Assuntos
Anemia Aplástica , COVID-19 , Enterocolite Neutropênica , Infecções por HIV , Infecções Fúngicas Invasivas , Pancitopenia , Anemia Aplástica/etiologia , Medula Óssea/patologia , COVID-19/complicações , Criança , Enterocolite Neutropênica/complicações , Feminino , Infecções por HIV/complicações , Humanos , Infecções Fúngicas Invasivas/complicações , Pancitopenia/diagnóstico , Pancitopenia/etiologia , SARS-CoV-2
8.
Parasit Vectors ; 15(1): 287, 2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-35945559

RESUMO

Aedes aegypti and Aedes albopictus are the main vectors of highly pathogenic viruses for humans, such as dengue (DENV), chikungunya (CHIKV), and Zika (ZIKV), which cause febrile, hemorrhagic, and neurological diseases and remain a major threat to global public health. The high ecological plasticity, opportunistic feeding patterns, and versatility in the use of urban and natural breeding sites of these vectors have favored their dispersal and adaptation in tropical, subtropical, and even temperate zones. Due to the lack of available treatments and vaccines, mosquito population control is the most effective way to prevent arboviral diseases. Resident microorganisms play a crucial role in host fitness by preventing or enhancing its vectorial ability to transmit viral pathogens. High-throughput sequencing and metagenomic analyses have advanced our understanding of the composition and functionality of the microbiota of Aedes spp. Interestingly, shotgun metagenomics studies have established that mosquito vectors harbor a highly conserved virome composed of insect-specific viruses (ISV). Although ISVs are not infectious to vertebrates, they can alter different phases of the arboviral cycle, interfering with transmission to the human host. Therefore, this review focuses on the description of Ae. aegypti and Ae. albopictus as vectors susceptible to infection by viral pathogens, highlighting the role of the microbiota-virome in vectorial competence and its potential in control strategies for new emerging and re-emerging arboviruses.


Assuntos
Aedes , Arbovírus , Infecção por Zika virus , Zika virus , Animais , Arbovírus/genética , Humanos , Mosquitos Vetores , Viroma , Zika virus/genética
9.
Sci Rep ; 12(1): 13653, 2022 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-35953498

RESUMO

Dengue is the most rapidly spreading vector-borne disease with an estimated 100-400 million cases each year. Control of Dengue vectors largely depends upon synthetic pyrethroids. Development of insecticide resistance in Aedes mosquitoes however, poses severe threat to insecticide-based vector management programme. Mutations in the Voltage Gated Sodium Channel gene (vgsc) serve as the primary machinery behind this resistance development. In Aedes albopictus, at least four such kdr (knock down resistance) mutations had already been documented. Here, we describe the occurrence of F1534C kdr mutation in wild population of Ae. albopictus from northern part of West Bengal, India including a novel T1520I mutation. Four populations of Ae. albopictus from the studied region were found resistant against DDT and synthetic pyrethroids, among them only one population possessed F1534C kdr mutation. A total of 200 successful amplification followed by partial sequencing of vgsc gene further revealed the presence of F1534C kdr mutation in both phenotypically susceptible and resistant mosquito specimen. Studied populations were found 81% homozygote susceptible (1534F/F), 12.5% heterozygote (1534F/C) and 6% homozygote resistant (1534C/C) for F1534C kdr mutation. The findings of the current study will help to uncover the mechanisms underlying insecticide resistance and hence to reduce errors in vector control measurements.


Assuntos
Aedes , Dengue , Inseticidas , Piretrinas , Canais de Sódio Disparados por Voltagem , Aedes/genética , Animais , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mosquitos Vetores/genética , Mutação , Nitrilas , Piretrinas/farmacologia , Canais de Sódio Disparados por Voltagem/genética
10.
Trends Parasitol ; 38(9): 791-804, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35952630

RESUMO

Mosquitoes are vectors for a number of infectious diseases. Only females feed on blood to provision for their embryos and, in doing so, transmit pathogens to the associated vertebrate hosts. Therefore, sex is an important phenotype in the context of genetic control programs, both for sex separation in the rearing facilities to avoid releasing biting females and for ways to distort the sex ratio towards nonbiting males. We review recent progress in the fundamental knowledge of sex determination and sex chromosomes in mosquitoes and discuss new methods to achieve sex separation and sex ratio distortion to help control mosquito-borne infectious diseases. We conclude by suggesting a few critical areas for future research.


Assuntos
Aedes , Culicidae , Doenças Transmitidas por Vetores , Animais , Culicidae/genética , Feminino , Masculino , Controle de Mosquitos , Mosquitos Vetores/genética , Doenças Transmitidas por Vetores/prevenção & controle
11.
Int J Mol Sci ; 23(15)2022 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-35955452

RESUMO

Repellents are among the leading products used against diseases transmitted by the Aedes aegypti mosquito. However, their indiscriminate use or high concentrations can cause severe adverse reactions, particularly in children and pregnant women. To protect them, nanotechnology is a promising tool to encapsulate active compounds against degradation, increase their effectiveness, and decrease their toxicity, as it can promote the modified release of the active compound. This study aimed to develop polymeric nanocapsules containing the repellent actives geraniol and icaridin using low concentrations of the active component, with the objective of promoting effective activity and greater safety against adverse reactions. The nanocapsules were developed by the interfacial deposition method, and the physicochemical properties of the nanocapsules were evaluated using dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), zeta potential, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), release kinetics assay, and mathematical modeling. Cell viability was assessed by the MTT assay and genotoxicity analysis using the comet assay. The developed nanocapsules containing geraniol and icaridin showed mean diameters of 260 nm and 314 nm, respectively, with a polydispersity index < 0.2. The nanocapsules showed encapsulation efficiency values of 73.7 ± 0.1% for icaridin and 98.7 ± 0.1% for geraniol. Morphological analysis showed spherical nanocapsules with low polydispersity. The kinetic parameters calculated using the Korsmeyer-Peppas model indicated an anomalous release profile. Cell viability and genotoxicity analyses showed that the nanocapsules did not alter cell viability or damage DNA. The results demonstrate a promising nanostructured system with good physicochemical characteristics and good stability, with repellent activity against Aedes aegypti.


Assuntos
Aedes , Repelentes de Insetos , Nanocápsulas , Monoterpenos Acíclicos , Animais , Criança , Feminino , Humanos , Repelentes de Insetos/farmacologia , Nanocápsulas/química , Piperidinas , Polímeros/farmacologia , Gravidez
12.
Nat Commun ; 13(1): 4490, 2022 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-35918360

RESUMO

First identified in 1947, Zika virus took roughly 70 years to cause a pandemic unusually associated with virus-induced brain damage in newborns. Zika virus is transmitted by mosquitoes, mainly Aedes aegypti, and secondarily, Aedes albopictus, both colonizing a large strip encompassing tropical and temperate regions. As part of the international project ZIKAlliance initiated in 2016, 50 mosquito populations from six species collected in 12 countries were experimentally infected with different Zika viruses. Here, we show that Ae. aegypti is mainly responsible for Zika virus transmission having the highest susceptibility to viral infections. Other species play a secondary role in transmission while Culex mosquitoes are largely non-susceptible. Zika strain is expected to significantly modulate transmission efficiency with African strains being more likely to cause an outbreak. As the distribution of Ae. aegypti will doubtless expand with climate change and without new marketed vaccines, all the ingredients are in place to relive a new pandemic of Zika.


Assuntos
Aedes , Infecção por Zika virus , Zika virus , Animais , Surtos de Doenças , Humanos , Recém-Nascido , Mosquitos Vetores
13.
Parasit Vectors ; 15(1): 277, 2022 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-35922821

RESUMO

BACKGROUND: Dengue is a major public health problem in Sri Lanka. Aedes vector surveillance and monitoring of larval indices are routine, long-established public health practices in the country. However, the association between Aedes larval indices and dengue incidence is poorly understood. It is crucial to evaluate lagged effects and threshold values of Aedes larval indices to set pragmatic targets for sustainable vector control interventions. METHODS: Monthly Aedes larval indices and dengue cases in all 10 Medical Officer of Health (MOH) divisions in Kalutara district were obtained from 2010 to 2019. Using a novel statistical approach, a distributed lag non-linear model and a two-staged hierarchical meta-analysis, we estimated the overall non-linear and delayed effects of the Premise Index (PI), Breteau Index (BI) and Container Index (CI) on dengue incidence in Kalutara district. A set of MOH division-specific variables were evaluated within the same meta-analytical framework to determine their moderator effects on dengue risk. Using generalized additive models, we assessed the utility of Aedes larval indices in predicting dengue incidence. RESULTS: We found that all three larval indices were associated with dengue risk at a lag of 1 to 2 months. The relationship between PI and dengue was homogeneous across MOH divisions, whereas that with BI and CI was heterogeneous. The threshold values of BI, PI and CI associated with dengue risk were 2, 15 and 45, respectively. All three indices showed a low to moderate accuracy in predicting dengue risk in Kalutara district. CONCLUSIONS: This study showed the potential of vector surveillance information in Kalutara district in developing a threshold-based, location-specific early warning system with a lead time of 2 months. The estimated thresholds are nonetheless time-bound and may not be universally applicable. Whenever longitudinal vector surveillance data areavailable, the methodological framework we propose here can be used to estimate location-specific Aedes larval index thresholds in any other dengue-endemic setting.


Assuntos
Aedes , Dengue , Animais , Dengue/epidemiologia , Humanos , Larva , Mosquitos Vetores , Sri Lanka/epidemiologia , Fatores de Tempo
14.
Bull Math Biol ; 84(9): 95, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35913683

RESUMO

In this paper, we propose a delay differential equation model to describe the Wolbachia infection dynamics in mosquitoes in which the key factor of cytoplasmic incompactibility (CI) is incorporated in a more natural way than those in the literature. By analyzing the dynamics of the model, we are able to obtain some information on the impact of four important parameters: the competition capabilities of the wild mosquitoes and infected mosquitoes, the maternal transmission level and the CI level. The analytic results show that there are ranges of parameters that support competition exclusion principle, and there are also ranges of parameters that allow co-persistence for both wild and infected mosquitoes. These ranges account for the scenarios of failure of invasion, invasion and suppressing the wild mosquitoes, and invasion and replacing the wild mosquitoes. We also discuss some possible future problems both in mathematics and in modeling.


Assuntos
Aedes , Wolbachia , Animais , Diclorodifenil Dicloroetileno , Conceitos Matemáticos , Modelos Biológicos
15.
Rev Sci Tech ; 41(1): 170-177, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35925624

RESUMO

The globalisation of trade is opening the way to the spread of species in new regions where they may cause negative impacts. Invasive mosquito species such as Aedes aegypti and Aedes albopictus are raising concern for their capacity to transmit several arboviruses of public health and veterinary importance. Currently available integrated vector management measures do not achieve satisfactory results when deployed against these urban mosquitoes. Moreover, insecticides are losing their effectiveness owing to the resistance developed by the target species. Policies regulating the use of insecticides are progressively restricting their market availability and this trend is expected to continue. Genetic control methods, such as the sterile insect technique (SIT), based on the use of irradiation to sterilise male mosquitoes, are showing good efficacy in pilot trials at local scales in some Aedes albopictus-colonised urban areas in Europe, without any negative effects. The main limitation is the cost, which may be significantly reduced through the introduction of automation in the mass rearing and drone technology in the field release. These technological advancements require substantial investments at a scale that can only be achieved with centralised production and extensive distribution, which in turn may be granted only if the authorisation frameworks, including the regulation of international transportation and aerial release in an urban setting, are clarified and matured.


La mondialisation des échanges ouvre une voie d'accès à la propagation d'espèces exotiques dans de nouvelles régions, avec parfois des effets négatifs. Les moustiques appartenant à des espèces envahissantes comme Aedes aegypti et Aedes albopictus suscitent à cet égard une certaine inquiétude en raison de leur capacité à transmettre plusieurs arbovirus importants pour la santé publique et vétérinaire. Les mesures disponibles de gestion intégrée des vecteurs ne donnent pas de résultats satisfaisants contre ces moustiques, à l'habitat principalement urbain. En outre, les insecticides perdent en efficacité à mesure que les espèces cibles acquièrent une résistance. La réglementation actuelle sur l'utilisation des insecticides vise à restreindre graduellement la disponibilité de ces produits sur le marché, tendance qui devrait se poursuivre. Les méthodes de contrôle génétique telles que la technique de l'insecte stérile (TIS), qui repose sur l'utilisation de moustiques mâles rendus stériles par irradiation, ont présenté une efficacité satisfaisante lors d'essais pilotes effectués à l'échelle locale dans certaines zones urbaines d'Europe colonisées par Aedes albopictus, sans induire d'effets indésirables. La principale limitation de cette méthode est son coüt, mais celui-ci peut être significativement réduit en automatisant les procédures d'élevage de masse et en utilisant des drones pour les lâchers sur le terrain. Ces avancées technologiques nécessitent d'importants investissements à très grande échelle, qui ne sont réalisables qu'en centralisant la production et en élargissant la distribution ; à son tour, cette perspective ne peut être garantie qu'à travers une clarification et rationalisation des cadres réglementaires régissant les autorisations nécessaires, en particulier concernant les transports internationaux et les lâchers aériens au-dessus des zones urbaines.


La mundialización del comercio está abriendo las puertas a la diseminación de especies en nuevas regiones, donde su presencia puede tener efectos negativos. Hay especies invasoras de mosquito, como Aedes aegypti o Aedes albopictus, que suscitan inquietud por su capacidad de transmitir varios arbovirus de importancia para la salud pública y veterinaria. Las medidas de lucha integrada contra vectores que existen actualmente no ofrecen resultados satisfactorios contra estos mosquitos urbanos. Además, los insecticidas están perdiendo eficacia debido a las resistencias adquiridas por las especies destinatarias. Las políticas que regulan el uso de insecticidas están restringiendo progresivamente su disponibilidad comercial, tendencia que presumiblemente va a perdurar. La aplicación experimental a escala local de métodos de control genético como la técnica del insecto estéril (sterile insect technique, SIT), basada en el uso de radiación para esterilizar a mosquitos macho, está resultando eficaz en ciertas zonas urbanas de Europa colonizadas por Aedes albopictus, sin que se observe ningún efecto negativo. La principal limitación es el costo, que cabe reducir sustancialmente introduciendo la automatización en la cría masiva y empleando drones para las sueltas sobre el terreno. Estos avances tecnológicos exigen inversiones cuantiosas, de tal magnitud que solo son factibles si se plantea una producción centralizada y una distribución a gran escala, procesos que a su vez solo serán aprobados si previamente se aclaran y perfeccionan los regímenes de autorización, incluida la regulación del transporte internacional y de la suelta aérea en medios urbanos.


Assuntos
Aedes , Inseticidas , Aedes/efeitos da radiação , Animais , Europa (Continente) , Espécies Introduzidas , Masculino , Mosquitos Vetores
16.
Rev Sci Tech ; 41(1): 91-99, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35925631

RESUMO

The Wolbachia insect control method, employed by the World Mosquito Program (WMP), relies on introgressing Wolbachia through target Aedes aegypti populations to reduce the incidence of dengue. Since 2010, the WMP has been producing Wolbachia-infected mosquitoes at numerous sites across the globe for release in 11 countries. As the technology has matured, greater focus has been placed on mosquito production at larger central facilities for transport to remote release sites, both domestically and internationally. Of particular note is the production of Wolbachia-infected mosquitoes at the WMP's Australian production facility for successful international deployments in Fiji, Vanuatu, Kiribati and Sri Lanka. This requires careful management of both production and supply-chain processes to ensure that the quality of the mosquito eggs, specifically the hatch rate and Wolbachia infection rate, is maintained. To ensure the cost-effectiveness and scalability of the Wolbachia method, these processes will be further refined to facilitate deployment from large centralised production facilities.


La méthode de contrôle des insectes mise en oeuvre par le World Mosquito Program (WMP) recourt à la bactérie Wolbachia et repose sur l'introgression de cette dernière par le biais des populations cibles d'Aedes aegypti dans le but de réduire l'incidence de la dengue. Depuis 2010, le WMP produit des moustiques infectés par Wolbachia à partir de nombreux sites répartis dans le monde entier en vue de leur lâcher dans 11 pays. Cette technologie s'étant bien développée, l'accent est désormais mis sur la production de moustiques dans des établissements centralisés de plus grande envergure afin de les expédier vers des sites de lâcher éloignés, tant sur le territoire national qu'à l'échelle internationale. Il importe de souligner la production de moustiques infectés par Wolbachia conduite par le WMP sur son site australien et leur déploiement international couronné de succès aux Fidji, au Vanuatu, à Kiribati et au Sri Lanka. Cela nécessite une gestion rigoureuse des procédures aussi bien lors de la production que tout au long de la chaîne d'approvisionnement afin de veiller au maintien de la qualité des oeufs de moustiques et plus spécifiquement du taux d'éclosion et du taux d'infection par Wolbachia. Afin d'assurer la rentabilité et l'évolutivité de la méthode basée sur Wolbachia, ces procédures seront encore affinées afin de faciliter le déploiement à partir de sites de production à grande échelle centralisés.


El método de control de insectos con Wolbachia que emplea el World Mosquito Program (WMP) reposa en la introgresión de Wolbachia a través de poblaciones de Aedes aegypti para reducir la incidencia del dengue. Desde 2010, el WMP viene generando mosquitos infectados por Wolbachia en numerosas instalaciones repartidas por todo el globo, mosquitos que después son liberados en 11 países. A medida que la tecnología ha ido madurando, la tendencia ha sido cada vez más la de concentrar la producción de mosquitos en grandes instalaciones centrales y desde allí enviarlos a los remotos lugares de suelta, ya estén en el mismo país o en otros países. Especialmente destacable es la producción de mosquitos infectados por Wolbachia en las instalaciones que el WMP tiene en Australia, utilizadas con éxito como centro de operaciones para aplicar el método en otros países como Fiji, Vanuatu, Kiribati y Sri Lanka. Ello exige una cuidadosa gestión de los procesos tanto de producción como de la cadena de suministro, que garantice un nivel constante de calidad de los huevos de mosquito, y más concretamente de las tasas de eclosión y de infección por Wolbachia. A fin de asegurar que el método ofrezca una buena relación costo-eficacia y sea reproducible a mayor escala, esos procesos serán perfeccionados para facilitar el despliegue de los insectos a partir de grandes instalaciones de producción centralizada.


Assuntos
Aedes , Dengue , Wolbachia , Animais , Austrália , Dengue/epidemiologia , Dengue/veterinária , Mosquitos Vetores , Óvulo , Controle Biológico de Vetores
17.
Parasit Vectors ; 15(1): 280, 2022 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-35932088

RESUMO

BACKGROUND: Colonization of large part of Europe by the Asian tiger mosquito Aedes albopictus is causing autochthonous transmission of chikungunya and dengue exotic arboviruses. While pyrethroids are recommended only to reduce/limit transmission, they are widely implemented to reduce biting nuisance and to control agricultural pests, increasing the risk of insurgence of resistance mechanisms. Worryingly, pyrethroid resistance (with mortality < 70%) was recently reported in Ae. albopictus populations from Italy and Spain and associated with the V1016G point mutation in the voltage-sensitive sodium channel gene conferring knockdown resistance (kdr). Genotyping pyrethroid resistance-associated kdr mutations in field mosquito samples represents a powerful approach to detect early signs of resistance without the need for carrying out phenotypic bioassays which require availability of live mosquitoes, dedicated facilities and appropriate expertise. METHODS: Here we report results on the PCR-genotyping of the V1016G mutation in 2530 Ae. albopictus specimens from 69 sampling sites in 19 European countries. RESULTS: The mutation was identified in 12 sites from nine countries (with allele frequencies ranging from 1 to 8%), mostly distributed in two geographical clusters. The western cluster includes Mediterranean coastal sites from Italy, France and Malta as well as single sites from both Spain and Switzerland. The eastern cluster includes sites on both sides of the Black Sea in Bulgaria, Turkey and Georgia as well as one site from Romania. These results are consistent with genomic data showing high connectivity and close genetic relationship among West European populations and a major barrier to gene flow between West European and Balkan populations. CONCLUSIONS: The results of this first effort to map kdr mutations in Ae. albopictus on a continental scale show a widespread presence of the V1016G allele in Europe, although at lower frequencies than those previously reported from Italy. This represents a wake-up call for mosquito surveillance programs in Europe to include PCR-genotyping of pyrethroid resistance alleles, as well as phenotypic resistance assessments, in their routine activities.


Assuntos
Aedes , Inseticidas , Piretrinas , Animais , Europa (Continente) , Genótipo , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mosquitos Vetores/genética , Mutação , Piretrinas/farmacologia
19.
Recurso na Internet em Português | LIS - Localizador de Informação em Saúde | ID: lis-49048

RESUMO

MS reforça importância da vacinação contra a febre amarela. Cerca de 15% das pessoas contaminadas podem desenvolver formas graves da doença; vacina é a principal forma de proteção.


Assuntos
Febre Amarela , Programas de Imunização
20.
PLoS Comput Biol ; 18(7): e1010314, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35867712

RESUMO

Quantifying the variation of pathogens' life history traits in multiple host systems is crucial to understand their transmission dynamics. It is particularly important for arthropod-borne viruses (arboviruses), which are prone to infecting several species of vertebrate hosts. Here, we focus on how host-pathogen interactions determine the ability of host species to transmit a virus to susceptible vectors upon a potentially infectious contact. Rift Valley fever (RVF) is a viral, vector-borne, zoonotic disease, chosen as a case study. The relative contributions of livestock species to RVFV transmission has not been previously quantified. To estimate their potential to transmit the virus over the course of their infection, we 1) fitted a within-host model to viral RNA and infectious virus measures, obtained daily from infected lambs, calves, and young goats, 2) estimated the relationship between vertebrate host infectious titers and probability to infect mosquitoes, and 3) estimated the net infectiousness of each host species over the duration of their infectious periods, taking into account different survival outcomes for lambs. Our results indicate that the efficiency of viral replication, along with the lifespan of infectious particles, could be sources of heterogeneity between hosts. Given available data on RVFV competent vectors, we found that, for similar infectious titers, infection rates in the Aedes genus were on average higher than in the Culex genus. Consequently, for Aedes-mediated infections, we estimated the net infectiousness of lambs to be 2.93 (median) and 3.65 times higher than that of calves and goats, respectively. In lambs, we estimated the overall infectiousness to be 1.93 times higher in individuals which eventually died from the infection than in those recovering. Beyond infectiousness, the relative contributions of host species to transmission depend on local ecological factors, including relative abundances and vector host-feeding preferences. Quantifying these contributions will ultimately help design efficient, targeted, surveillance and vaccination strategies.


Assuntos
Aedes , Vírus da Febre do Vale do Rift , Animais , Gado , Mosquitos Vetores , Ovinos , Vertebrados , Carga Viral
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