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1.
Recurso na Internet em Português | LIS - Localizador de Informação em Saúde | ID: lis-48419

RESUMO

Um microorganismo implantado em mosquitos reduziu em 70% a ocorrência de casos de dengue, 66% de incidência de casos de chinkungunya e 40% de Zika em Niterói, no Rio de Janeiro.


Assuntos
Dengue/prevenção & controle , Zika virus , Planos e Programas de Pesquisa em Saúde , Aedes , Wolbachia
2.
Braz J Biol ; 83: e246230, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34495158

RESUMO

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.


Assuntos
Aedes , Fusarium , Inseticidas , Animais , Florestas , Humanos , Inseticidas/farmacologia , Larva , Mosquitos Vetores , Paquistão , Extratos Vegetais , Solo
3.
Int J Mol Sci ; 22(16)2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34445622

RESUMO

Vector-borne diseases have appeared or re-emerged in many Southern Europe countries making the transmission of infectious diseases by mosquitoes (vectors) one of the greatest worldwide health threats. Larvicides have been used extensively for the control of Aedes (Stegomyia) albopictus (Skuse, 1895) (Diptera: Culicidae) and Culex pipiens Linnaeus, 1758 (Diptera: Culicidae) mosquitoes in urban and semi-urban environments, causing the increasing resistance of mosquitoes to commercial insecticides. In this study, 27 curcuminoids and monocarbonyl curcumin derivatives were synthesised and evaluated as potential larvicidal agents against Cx. pipiens and Ae. albopictus. Most of the compounds were more effective against larvae of both mosquito species. Four of the tested compounds, curcumin, demethoxycurcumin, curcumin-BF2 complex and a monocarbonyl tetramethoxy curcumin derivative exhibited high activity against both species. In Cx. pipiens the recorded LC50 values were 6.0, 9.4, 5.0 and 32.5 ppm, respectively, whereas in Ae. albopictus they exhibited LC50 values of 9.2, 36.0, 5.5 and 23.6 ppm, respectively. No conclusive structure activity relationship was evident from the results and the variety of descriptors values generated in silico provided some insight to this end.


Assuntos
Aedes/efeitos dos fármacos , Culex/efeitos dos fármacos , Curcumina/química , Curcumina/farmacologia , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Mosquitos Vetores/efeitos dos fármacos , Animais , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Feminino , Inseticidas/química
4.
Pestic Biochem Physiol ; 178: 104911, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34446187

RESUMO

Commercial insecticide aerosol sprays are widely used in households for controlling Aedes aegypti and Culex quinquefasciatus, the primary vectors of dengue virus and filarial worm, respectively. In Thailand, however, both mosquitoes are resistant to pyrethroids conferred by knockdown resistance (kdr) mutations, V1016G and F1534C in Ae. aegypti and L1014F in Cx. quinquefasciatus. This study evaluated the efficacy of five sprays (coded as AS1-AS5) with different formulations of pyrethroids against wild mosquitoes by using a cage bioassay in a furnished bedroom of a house. Five cages containing wild mosquitoes and five cages containing a pyrethroid susceptible strain of Ae. aegypti (25 females each), as a bio-indicator, were allocated in the room and spraying was operated for 15 s. Survivors and dead mosquitoes were genotyped individually for the kdr mutations using allele-specific PCR methods. Both mosquito species showed a high resistance to permethrin and deltamethrin with 12.5-58.0% mortality rates. For controlling Ae. aegypti, the spray AS4 showed the highest efficacy (mortality rates 76.0-100.0%, mean 95.2%), followed by AS2 (73.0-100.0%, mean 93.8%). For controlling Cx. quinquefasciatus, the best result was obtained from AS4 (66.0-98.0% mortality, mean 89.8%), followed by AS2 (73.0-97.0%, mean 84.5%). The sprays (AS4 and AS2) containing both type I and type II pyrethroids were more effective than those containing only type I pyrethroids or pyrethrum with the synergist piperonyl butoxide. The mutant G1016 and F1014 allele frequencies were significantly higher in the survivor groups than the dead groups of Ae. aegypti and Cx. quinquefasciatus, respectively, (P < 0.05). The efficacy of the sprays varied depending on the mosquito species, formulations, nozzles and locations of caged mosquitoes. The V1016G and L1014F mutations are associated with the reduced efficacy of sprays used in households for controlling resistant Ae. aegypti and Cx. quinquefasciatus mosquitoes, respectively.


Assuntos
Aedes , Culex , Inseticidas , Piretrinas , Aedes/genética , Aerossóis , Animais , Culex/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mosquitos Vetores/genética , Tailândia
5.
Pestic Biochem Physiol ; 178: 104912, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34446188

RESUMO

Intracellular effects exerted by phytochemicals eliciting insect growth-retarding responses during vector control intervention remain largely underexplored. We studied the effects of Zanthoxylum chalybeum Engl. (Rutaceae) (ZCE) root derivatives against malaria (Anopheles gambiae) and arbovirus vector (Aedes aegypti) larvae to decipher possible molecular targets. We report dose-dependent biphasic effects on larval response, with transient exposure to ZCE and its bioactive fraction (ZCFr.5) inhibiting acetylcholinesterase (AChE) activity, inducing larval lethality and growth retardation at sublethal doses. Half-maximal lethal concentrations (LC50) for ZCE against An. gambiae and Ae. aegypti larvae after 24-h exposure were 9.00 ppm and 12.26 ppm, respectively. The active fraction ZCFr.5 exerted LC50 of 1.58 ppm and 3.21 ppm for An. gambiae and Ae. aegypti larvae, respectively. Inhibition of AChE was potentially linked to larval toxicity afforded by 2-tridecanone, palmitic acid (hexadecanoic acid), linoleic acid ((Z,Z)-9,12-octadecadienoic acid), sesamin, ß-caryophyllene among other compounds identified in the bioactive fraction. In addition, the phenotypic larval retardation induced by ZCE root constituents was exerted through transcriptional modulation of ecdysteroidogenic CYP450 genes. Collectively, these findings provide an explorative avenue for developing potential mosquito control agents from Z. chalybeum root constituents.


Assuntos
Aedes , Culex , Inseticidas , Zanthoxylum , Animais , Transtornos do Crescimento , Inseticidas/toxicidade , Larva , Controle de Mosquitos , Mosquitos Vetores , Extratos Vegetais
6.
Parasite ; 28: 60, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34374642

RESUMO

Between 2016 and 2020, the Medical and Veterinary Entomology unit of the Institut Pasteur du Cambodge collected over 230,000 mosquitoes. Based on this sampling effort, a checklist of 290 mosquito species in Cambodia is presented. This is the first attempt to list the Culicidae fauna of the country. We report 49 species for the first time in Cambodia. The 290 species belong to 20 genera: Aedeomyia (1 sp.), Aedes (55 spp.), Anopheles (53 spp.), Armigeres (26 spp.), Coquillettidia (3 spp.), Culex (57 spp.), Culiseta (1 sp.), Ficalbia (1 sp.), Heizmannia (10 spp.), Hodgesia (3 spp.), Lutzia (3 spp.), Malaya (2 spp.), Mansonia (5 spp.), Mimomyia (7 spp.), Orthopodomyia (3 spp.), Topomyia (4 spp.), Toxorhynchites (4 spp.), Tripteroides (6 spp.), Uranotaenia (27 spp.), and Verrallina (19 spp.). The Cambodian Culicidae fauna is discussed in its Southeast Asian context. Forty-three species are reported to be of medical importance, and are involved in the transmission of pathogens.


Assuntos
Aedes , Culex , Culicidae , Animais , Camboja , Lista de Checagem , Mosquitos Vetores
8.
Artigo em Inglês | MEDLINE | ID: mdl-34406289

RESUMO

Infections caused by arboviruses that have mostly impacted the Brazilian morbidity and mortality are caused by the same vector, Aedes aegypti. Preventive actions related to the vector are the most effective strategies in the prevention and control of these diseases. This study aimed to associate the knowledge on the vector that transmits dengue, Zika and chikungunya with the sociodemographic and behavioral preventive practices towards Aedes aegypti in the municipality of Tangara da Serra, Mato Grosso State, in the Brazilian Legal Amazon. A probabilistic urban population sampling was obtained by clusters: census sectors and households. The sample size calculation considered 10% of loss and a 1.5 design effect. This is a cross-sectional research carried out through a household survey in February and March 2018. There were 583 participants. The study variables were knowledge on the vector, sociodemographic characteristics and preventive practices related to the vector. The statistical analysis was based on a bivariate analysis and Poisson multiple regressions. Inadequate or insufficient knowledge on the vector Aedes aegypti remained associated with education in the categories illiterate (p<0.001) and 8 years of study or less (p<0.001), in addition to not adopting practices of capping and cleaning the water tank (p=0.002) and not using insecticides at home (p=0.007). It is concluded that there is a need for health communication actions that consider characteristics the population, especially the level of education and previous knowledge on the vector, allowing a dialogical approach and enabling the community participation in preventive practices and control of the vector Aedes aegypti .


Assuntos
Aedes , Dengue , Infecção por Zika virus , Zika virus , Animais , Estudos Transversais , Dengue/prevenção & controle , Humanos , Controle de Mosquitos , Mosquitos Vetores , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/prevenção & controle
9.
J Med Entomol ; 58(5): 2006-2011, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34342359

RESUMO

Medical Entomology as a field is inherently global - thriving on international and interdisciplinary collaborations and affected dramatically by arthropod and pathogen invasions and introductions. This past year also will be remembered as the year in which the SARS-CoV-2 COVID-19 pandemic affected every part of our lives and professional activities and impacted (or changed, sometimes in good ways) our ability to collaborate and detect or respond to invasions. This incredible year is the backdrop for the 2020 Highlights in Medical Entomology. This article highlights the broad scope of approaches and disciplines represented in the 2020 published literature, ranging from sensory and chemical ecology, population genetics, impacts of human-mediated environmental change on vector ecology, life history and the evolution of vector behaviors, to the latest developments in vector surveillance and control.


Assuntos
Entomologia , Aedes , Animais , COVID-19/epidemiologia , Meio Ambiente , Humanos , Controle de Insetos , Insetos Vetores , Doenças Transmitidas por Carrapatos/epidemiologia , Carrapatos
10.
J Gen Virol ; 102(8)2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34410905

RESUMO

The capsid protein (C) of dengue virus is required for viral infectivity as it packages viral RNA genome into infectious particles. C exists as a homodimer that forms via hydrophobic interactions between the α2 and α4 helices of monomers. To identify C region(s) important for virus particle production, a complementation system was employed in which single-round infectious particles are generated by trans-encapsidation of a viral C-deleted genome by recombinant C expressed in mosquito cells. Mutants harbouring a complete α3 deletion, or a dual Ile65-/Trp69-to-Ala substitution in the α3 helix, exhibited reduced production of infectious virus. Unexpectedly, higher proportions of oligomeric C were detected in cells expressing both mutated forms as compared with the wild-type counterpart, indicating that the α3 helix, through its internal hydrophobic residues, may down-modulate oligomerization of C during particle formation. Compared with wild-type C, the double Ile65-/Trp69 to Ala mutations appeared to hamper viral infectivity but not C and genomic RNA incorporation into the pseudo-infectious virus particles, suggesting that increased C oligomerization may impair DENV replication at the cell entry step.


Assuntos
Proteínas do Capsídeo , Capsídeo/metabolismo , Vírus da Dengue/metabolismo , Dengue/virologia , Aedes , Sequência de Aminoácidos , Animais , Proteínas do Capsídeo/química , Proteínas do Capsídeo/metabolismo , Chlorocebus aethiops , Humanos , Células Vero , Montagem de Vírus , Replicação Viral
11.
Epidemiol Infect ; 149: e188, 2021 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-34338179

RESUMO

In 2015-2016, simultaneous circulation of dengue, Zika and chikungunya in the municipality of Rio de Janeiro (Brazil) was reported. We conducted an ecological study to analyse the spatial distribution of dengue, Zika and chikungunya cases and to investigate socioeconomic factors associated with individual and combined disease incidence in 2015-2016. We then constructed thematic maps and analysed the bivariate global Moran indices. Classical and spatial models were used. A distinct spatial distribution pattern for dengue, Zika and chikungunya was identified in the municipality of Rio de Janeiro. The bivariate global Moran indices (P < 0.05) revealed negative spatial correlations between rates of dengue, Zika, chikungunya and combined arboviruses incidence and social development index and mean income. The regression models (P < 0.05) identified a negative relationship between mean income and each of these rates and between sewage and Zika incidence rates, as well as a positive relationship between urban areas and chikungunya incidence rates. In our study, spatial analysis techniques helped to identify high-risk and social determinants at the local level for the three arboviruses. Our findings may aid in backing effective interventions for the prevention and control of epidemics of these diseases.


Assuntos
Febre de Chikungunya/epidemiologia , Dengue/epidemiologia , Fatores Socioeconômicos , Infecção por Zika virus/epidemiologia , Aedes/virologia , Animais , Brasil/epidemiologia , Febre de Chikungunya/transmissão , Cidades , Estudos Transversais , Dengue/transmissão , Epidemias , Humanos , Incidência , Insetos Vetores/virologia , Modelos Estatísticos , Análise Espacial , Infecção por Zika virus/transmissão
12.
J Agric Food Chem ; 69(33): 9684-9692, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34387470

RESUMO

The use of N-aryl amide derivatives as spatially acting insecticides remains relatively unexplored. To expand this knowledge, we synthesized eighty-nine N-aryl amide analogues and screened them for mortality against an insecticide-susceptible strain of Aedes aegypti mosquitoes, Orlando (OR), using a vapor exposure glass tube assay. Of the screened compounds, twenty-two produced >92% mortality at 24 h and warranted further investigation to determine LC50 values. Fifteen of these analogues had LC50 values within 2 orders of magnitude of transfluthrin, and of significant interest, N-(2,6-dichloro-4-(trifluoromethyl)phenyl)-2,2,3,3,3-pentafluoropropanamide (compound 70) was nearly as potent as transfluthrin and exhibited greater toxicity than metofluthrin when screened against OR A. aegypti. Compounds exhibiting potent toxicity against OR A. aegypti or whose structure-activity relationship potentially offered beneficial insights into structure optimization were screened against the insecticide-resistant, Puerto Rico (PR), strain of A. Aegypti, and it was discovered that not only did these N-arylamides typically show little resistance, some such as N-(2,6-dichloropyridin-4-yl)-2,2,3,3,4,4,4-heptafluorobutanamide (compound 36) and 2,2,3,3,4,4,4-heptafluoro-N-(3,4,5-trifluorophenyl)butanamide (compound 40) were actually more potent against the PR mosquitoes. Due to this promising insecticidal activity, five compounds were administered orally to mice to determine acute oral rodent toxicity. All five compounds were found to have mouse oral toxicity LD50 values well above the minimum safe level as set by the Innovative Vector Control Consortium (50 mg/kg). In addition to the promising biological activity documented here, we report the structure-activity relationship analysis used to guide the derivatization approach taken and to further inform future efforts in the development of N-arylamides as potential resistance-breaking, spatially acting insecticides.


Assuntos
Aedes , Inseticidas , Animais , Bioensaio , Inseticidas/farmacologia , Camundongos , Mosquitos Vetores , Relação Estrutura-Atividade
13.
Bull World Health Organ ; 99(8): 583-592, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34354313

RESUMO

Water-related diseases such as diarrhoeal diseases from viral, bacterial and parasitic organisms and Aedes-borne arboviral diseases are major global health problems. We believe that these two disease groups share common risk factors, namely inadequate household water management, poor sanitation and solid waste management. Where water provision is inadequate, water storage is essential. Aedes mosquitoes commonly breed in household water storage containers, which can hold water contaminated with enteric disease-causing organisms. Microbiological contamination of water between source and point-of-use is a major cause of reduced drinking-water quality. Inadequate sanitation and solid waste management increase not only risk of water contamination, but also the availability of mosquito larval habitats. In this article we discuss integrated interventions that interrupt mosquito breeding while also providing sanitary environments and clean water. Specific interventions include improving storage container design, placement and maintenance and scaling up access to piped water. Vector control can be integrated into sanitation projects that target sewers and drains to avoid accumulation of stagnant water. Better management of garbage and solid waste can reduce the availability of mosquito habitats while improving human living conditions. Our proposed integration of disease interventions is consistent with strategies promoted in several global health frameworks, such as the sustainable development goals, the global vector control response, behavioural change, and water, sanitation and hygiene initiatives. Future research should address how interventions targeting water, sanitation, hygiene and community waste disposal also benefit Aedes-borne disease control. The projected effects of climate change mean that integrated management and control strategies will become increasingly important.


Assuntos
Aedes , Prestação Integrada de Cuidados de Saúde , Diarreia/prevenção & controle , Controle de Mosquitos , Mosquitos Vetores , Saneamento , Purificação da Água , Animais , Diarreia/epidemiologia , Gerenciamento Clínico , Humanos , Microbiologia da Água , Abastecimento de Água
14.
BMC Health Serv Res ; 21(1): 866, 2021 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-34429111

RESUMO

BACKGROUND: Effective control of emerging mosquito-borne viral diseases such as dengue, chikungunya, and Zika requires, amongst other things, a functional healthcare system, ready and capable of timely detection and prompt response to incipient epidemics. We assessed the readiness of Zanzibar health facilities and districts for early detection and management of mosquito-borne viral disease outbreaks. METHODS: A cross-sectional study involving all 10 District Health Management Teams and 45 randomly selected public and private health facilities in Zanzibar was conducted using a mixed-methods approach including observations, document review, and structured interviews with health facility in-charges and District Health Management Team members. RESULTS: The readiness of the Zanzibar healthcare system for timely detection, management, and control of dengue and other mosquito-borne viral disease outbreaks was critically low. The majority of health facilities and districts lacked the necessary requirements including standard guidelines, trained staff, real-time data capture, analysis and reporting systems, as well as laboratory diagnostic capacity. In addition, health education programmes for creating public awareness and Aedes mosquito surveillance and control activities were non-existent. CONCLUSIONS: The Zanzibar healthcare system has limited readiness for management, and control of mosquito-borne viral diseases. In light of impending epidemics, the critical shortage of skilled human resource, lack of guidelines, lack of effective disease and vector surveillance and control measures as well as lack of laboratory capacity at all levels of health facilities require urgent attention across the Zanzibar archipelago.


Assuntos
Aedes , Epidemias , Viroses , Infecção por Zika virus , Zika virus , Animais , Estudos Transversais , Atenção à Saúde , Humanos , Mosquitos Vetores , Tanzânia/epidemiologia , Infecção por Zika virus/diagnóstico , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/prevenção & controle
15.
Viruses ; 13(7)2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-34372574

RESUMO

The mosquito-borne flavivirus, Kedougou virus (KEDV), first isolated in Senegal in 1972, is genetically related to dengue, Zika (ZIKV) and Spondweni viruses (SPOV). Serological surveillance studies in Senegal and isolation of KEDV in the Central African Republic indicate occurrence of KEDV infections in humans, but to date, no disease has been reported. Here, we assembled the coding-complete genome of a 1958 isolate of KEDV from a pool of Aedes circumluteolus mosquitoes collected in Ndumu, KwaZulu-Natal, South Africa. The AR1071 Ndumu KEDV isolate bears 80.51% pairwise nucleotide identity and 93.34% amino acid identity with the prototype DakAar-D1470 strain and was co-isolated with SPOV through intracerebral inoculation of suckling mice and passage on VeroE6 cells. This historical isolate expands the known geographic and temporal range of this relatively unknown flavivirus, aiding future temporal phylogenetic calibration and diagnostic assay refinement.


Assuntos
Infecções por Flavivirus/epidemiologia , Flavivirus/genética , Aedes/virologia , Animais , Monitoramento Epidemiológico , Flavivirus/metabolismo , Flavivirus/patogenicidade , Infecções por Flavivirus/genética , História do Século XX , Humanos , Mosquitos Vetores/virologia , Filogenia , África do Sul/epidemiologia , Doenças Transmitidas por Vetores/história
16.
Oecologia ; 196(4): 1061-1072, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34338862

RESUMO

Processes that change with density are inherent in all populations, yet quantifying density dependence with empirical data remains a challenge. This is especially true for animals recruiting in patchy landscapes because heterogeneity in habitat quality in combination with habitat choice can obscure patterns expected from density dependence. Mosquitoes (Diptera: Culicidae) typically experience strong density dependence when larvae compete for food, however, effects vary across species and contexts. If populations experience intense intraspecific density-dependent mortality then overcompensation can occur, where the number of survivors declines at high densities producing complex endogenous dynamics. To seek generalizations about density dependence in a widespread species of Arctic mosquito, Aedes nigripes, we combined a laboratory experiment, field observations, and modeling approaches. We evaluated alternative formulations of discrete population models and compared best-performing models from our lab study to larval densities from ponds in western Greenland. Survivorship curves from the lab were the best fit by a Hassell model with compensating density dependence (equivalent to a Beverton-Holt model) where peak recruitment ranged from 8 to 80 mosquitoes per liter depending on resource supply. In contrast, our field data did not show a signal of strong density dependence, suggesting that other processes such as predation may lower realized densities in nature, and that expected patterns may be obscured because larval abundance covaries with resources (cryptic density dependence). Our study emphasizes the importance of covariation between the environment, habitat choice, and density dependence in understanding population dynamics across landscapes, and demonstrates the value of pairing lab and field studies.


Assuntos
Aedes , Animais , Larva , Densidade Demográfica , Dinâmica Populacional , Comportamento Predatório
18.
Front Cell Infect Microbiol ; 11: 702081, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34268140

RESUMO

Aedes albopictus is the only vector that can transmit the dengue virus in Zhejiang Province, central China, and it can develop insecticide resistance due to long-term exposure to pyrethroids. The presence of knockdown resistance (kdr) mutations is one of the mechanisms responsible for pyrethroid resistance, and has been reported in some Ae. albopictus populations in southern China. However, little is known about the DNA diversity of the voltage-gated sodium channel (VGSC) gene in Ae. albopictus populations in central China. Four Ae. albopictus field populations were collected, in Yiwu (YW), Quzhou (QZ), Wenzhou (WZ), and Jiaxing (JX) from Zhejiang Province, central China. The susceptibility of Ae. albopictus adults to three pyrethroids (beta-cypermethrin, deltamethrin, and permethrin) was tested using the WHO tube assay, and Kdr mutations were identified via PCR and sequencing. The relationship between kdr mutations and pyrethroid phenotypes was also analyzed. Of the four populations, none was sensitive to any pyrethroid tested, and the YW population showed the strongest pyrethroid resistance. Non-synonymous kdr mutations were detected in codons 1532 and 1534, domain III. At codon 1534, one mutant allele, TCC(S), was detected in the four populations with a frequency of 42.08%, while at codon 1532, one mutant allele, ACC(T), was detected in the JX and QZ populations, with frequencies of 4.22 and 3.03%, respectively. The F1534S mutant allele was positively correlated with both beta-cypermethrin and deltamethrin resistance phenotypes (OR > 1, P < 0.05), whereas the I1532T mutant allele was possibly negatively correlated with beta-cypermethrin, deltamethrin, and permethrin resistance phenotypes (OR < 1, P > 0.05). In conclusion, resistance and resistance mutations regarding to three pyrethroids are already present in the Ae. Albopictus populations from Zhejiang, central China, which prompts the need to use non-insecticide-based methods of insect control.


Assuntos
Aedes , Inseticidas , Aedes/genética , Animais , China , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mosquitos Vetores/genética , Mutação
19.
Front Cell Infect Microbiol ; 11: 690087, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34249780

RESUMO

Aedes aegypti is inherently susceptible to arboviruses. The geographical expansion of this vector host species has led to the persistence of Dengue, Zika, and Chikungunya human infections. These viruses take advantage of the mosquito's cell to create an environment conducive for their growth. Arboviral infection triggers transcriptomic and protein dysregulation in Ae. aegypti and in effect, host antiviral mechanisms are compromised. Currently, there are no existing vaccines able to protect human hosts from these infections and thus, vector control strategies such as Wolbachia mass release program is regarded as a viable option. Considerable evidence demonstrates how the presence of Wolbachia interferes with arboviruses by decreasing host cytoskeletal proteins and lipids essential for arboviral infection. Also, Wolbachia strengthens host immunity, cellular regeneration and causes the expression of microRNAs which could potentially be involved in virus inhibition. However, variation in the magnitude of Wolbachia's pathogen blocking effect that is not due to the endosymbiont's density has been recently reported. Furthermore, the cellular mechanisms involved in this phenotype differs depending on Wolbachia strain and host species. This prompts the need to explore the cellular interactions between Ae. aegypti-arboviruses-Wolbachia and how different Wolbachia strains overall affect the mosquito's cell. Understanding what happens at the cellular and molecular level will provide evidence on the sustainability of Wolbachia vector control.


Assuntos
Aedes , Arbovírus , Wolbachia , Infecção por Zika virus , Zika virus , Animais , Humanos , Mosquitos Vetores
20.
Artigo em Inglês | MEDLINE | ID: mdl-34299819

RESUMO

Since 1994, dengue fever (DF) transmission rates have increased significantly in Saudi Arabia (KSA). Climatic, geographic, and demographic conditions make KSA especially suitable for DF's spread. Still, there are insufficient strategies for controlling the Aedes species that transmit DF virus (DENV). To develop effective management strategies, it is necessary to identify Aedes species and the ecological habitat of larvae in Makkah Al-Mokarramah, KSA. We conducted a longitudinal survey of Aedes mosquitoes in 14 localities from January 2015 to December 2015. World Health Organization (WHO) inspection kits for larvae were used to detect and sample larvae, along with pictorial keys. A total of 42,981 potential Aedes larval breeding sites were surveyed. A total of 5403 (12.6%) sites had at least one water source positive for Aedes aegypti (Linnaeus) mosquitoes. Among the total of 15,133 water sources surveyed within the sampled sites, 1815 (12.0%) were positive for Aedes aegypti. Aedes aegypti was the only Aedes species identified in the course of the survey. The presence of such a large immature population may indicate an imminent outbreak of DF in the near future unless proper implementation of control and elimination of Aedes aegypti are undertaken. Additionally, the adaptation of Aedes aegypti to the arid climate of Makkah needs further investigation.


Assuntos
Aedes , Dengue , Animais , Dengue/epidemiologia , Larva , Prevalência , Arábia Saudita/epidemiologia , Estações do Ano
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