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1.
SAR QSAR Environ Res ; 31(10): 717-739, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32930630

RESUMO

Aedes aegypti is the primary vector of several infectious viruses that cause yellow, dengue, chikungunya, and Zika fevers. Recently, plant-derived products have been tested as safe and eco-friendly larvicides against Ae. aegypti. The present study aimed to improve QSAR models for 62 larvicidal phytocompounds against Ae. aegypti via the Monte Carlo method based on the index of the ideality of correlation (IIC) criterion. The representation of structures was done with SMILES. Three splits were prepared randomly and three QSAR models were constructed using IIC target function. The molecular descriptors were selected from SMILES descriptors and the hydrogen-filled molecular graphs. The predictability of three models was evaluated on the validation sets, the r 2 of which was 0.9770, 0.8660, and 0.8565 for models 1 to 3, respectively. The statistical results of three randomized splits indicated that robust, simple, predictive, and reliable models were obtained for different sets. From the modelling results, important descriptors were identified to enhance and reduce the larvicidal activity of compounds. Based on the identified important descriptors, some new structures of larvicidal compounds were proposed. The larvicidal activity of novel molecules designed further was supported by docking studies. Using the simple QSAR model, one can predict pLC50 of new similarity larvicidal phytocompounds.


Assuntos
Aedes/efeitos dos fármacos , Inseticidas/farmacologia , Mosquitos Vetores/efeitos dos fármacos , Relação Quantitativa Estrutura-Atividade , Aedes/crescimento & desenvolvimento , Animais , Inseticidas/química , Larva/efeitos dos fármacos , Mosquitos Vetores/crescimento & desenvolvimento
2.
PLoS Negl Trop Dis ; 14(8): e0008669, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32866146

RESUMO

Exposure of adult mosquitoes to pyriproxyfen (PPF), an analog of insect juvenile hormone (JH), has shown promise to effectively sterilize female mosquitoes. However, the underlying mechanisms of the PPF-induced decrease in mosquito fecundity are largely unknown. We performed a comprehensive study to dissect the mode of PPF action in Aedes aegypti mosquitoes. Exposure to PPF prompted the overgrowth of primary follicles in sugar-fed Ae. aegypti females but blocked the development of primary follicles at Christopher's Stage III after blood feeding. Secondary follicles were precociously activated in PPF-treated mosquitoes. Moreover, PPF substantially altered the expression of many genes that are essential for mosquito physiology and oocyte development in the fat body and ovary. In particular, many metabolic genes were differentially expressed in response to PPF treatment, thereby affecting the mobilization and utilization of energy reserves. Furthermore, PPF treatment on the previtellogenic female adults considerably modified mosquito responses to JH and 20-hydroxyecdysone (20E), two major hormones that govern mosquito reproduction. Krüppel homolog 1, a JH-inducible transcriptional regulator, showed consistently elevated expression after PPF exposure. Conversely, PPF upregulated the expression of several key players of the 20E regulatory cascades, including HR3 and E75A, in the previtellogenic stage. After blood-feeding, the expression of these 20E response genes was significantly weaker in PPF-treated mosquitoes than the solvent-treated control groups. RNAi-mediated knockdown of the Methoprene-tolerant (Met) protein, the JH receptor, partially rescued the impaired follicular development after PPF exposure and substantially increased the hatching of the eggs produced by PPF-treated female mosquitoes. Thus, the results suggested that PPF relied on Met to exert its sterilizing effects on female mosquitoes. In summary, this study finds that PPF exposure disturbs normal hormonal responses and metabolism in Ae. aegypti, shedding light on the molecular targets and the downstream signaling pathways activated by PPF.


Assuntos
Aedes/efeitos dos fármacos , Culicidae/efeitos dos fármacos , Inseticidas/farmacologia , Metoprene/metabolismo , Esterilização , Animais , Ecdisterona/farmacologia , Corpo Adiposo/crescimento & desenvolvimento , Feminino , Glicogênio/metabolismo , Proteínas de Insetos/genética , Hormônios Juvenis/farmacologia , Ovário/crescimento & desenvolvimento , Piridinas , Interferência de RNA , Triglicerídeos/metabolismo
3.
PLoS Negl Trop Dis ; 14(8): e0008660, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32866199

RESUMO

Aedes mosquitoes can transmit dengue and several other severe vector-borne viral diseases, thereby influencing millions of people worldwide. Insects primarily control and clear the viral infections via their innate immune systems. Mitogen-Activated Protein Kinases (MAPKs) and antimicrobial peptides (AMPs) are both evolutionarily conserved components of the innate immune systems. In this study, we investigated the role of MAPKs in Aedes mosquitoes following DENV infection by using genetic and pharmacological approaches. We demonstrated that knockdown of ERK, but not of JNK or p38, significantly enhances the viral replication in Aedes mosquito cells. The Ras/ERK signaling is activated in both the cells and midguts of Aedes mosquitoes following DENV infection, and thus plays a role in restricting the viral infection, as both genetic and pharmacological activation of the Ras/ERK pathway significantly decreases the viral titers. In contrast, inhibition of the Ras/ERK pathway enhances DENV infection. In addition, we identified a signaling crosstalk between the Ras/ERK pathway and DENV-induced AMPs in which defensin C participates in restricting DENV infection in Aedes mosquitoes. Our results reveal that the Ras/ERK signaling pathway couples AMPs to mediate the resistance of Aedes mosquitoes to DENV infection, which provides a new insight into understanding the crosstalk between MAPKs and AMPs in the innate immunity of mosquito vectors during the viral infection.


Assuntos
Aedes/virologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Vírus da Dengue/imunologia , Quinases de Proteína Quinase Ativadas por Mitógeno/farmacologia , Mosquitos Vetores/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Animais , Anti-Infecciosos/farmacologia , Linhagem Celular , Sistema Digestório/virologia , Feminino , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Imunidade Inata , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Mosquitos Vetores/virologia , Carga Viral , Replicação Viral/efeitos dos fármacos
4.
Rev Prat ; 70(3): 318-325, 2020 Mar.
Artigo em Francês | MEDLINE | ID: mdl-32877069

RESUMO

Dengue fever: an emerging infectious disease. Dengue fever is caused by an arbovirus of the family Flaviviridae and the genus Flavivirus, of which there are 4 serotypes (DEN-1, DEN-2, DEN-3, DEN-4). It is transmitted by the bite of a diurnal mosquito of the genus Aedes, mainly A. aegypti and A. albopictus. An increasing cause of acute fever in travellers, it threatens to emerge in temperate regions where competent mosquitoes (Aedes) are established. Dengue fever is characterized by its clinical polymorphism ranging from asymptomatic to severe forms, which are rare in travellers. Its definite diagnosis is based on virological tests selected according to the stage of the disease and the kinetics of the virus. Its treatment is only symptomatic. It is a notifiable disease in mainland France and is subject to a plan to combat its spread and to specific surveillance in the overseas departments. Dengue prevention is based on the application of personal anti-vectorial protection measures among travellers, awareness-raising among health professionals and social mobilization to combat larval gites in endemic regions or regions colonized by Aedes. In France, the tetravalent vaccine Dengvaxia, which is licensed in France, is not recommended for people residing in overseas departments and for travelers to endemic areas.


Assuntos
Aedes , Doenças Transmissíveis Emergentes , Vírus da Dengue , Dengue , Animais , Dengue/epidemiologia , Dengue/transmissão , França/epidemiologia , Medicina de Viagem
5.
Rev Prat ; 70(3): 336-340, 2020 Mar.
Artigo em Francês | MEDLINE | ID: mdl-32877073

RESUMO

Chikungunya. Chikungunya is a cosmopolitan arbovirosis transmitted by a mosquito of the genus Aedes. It is characterized by the possible persistence of musculoskeletal symptoms more than three months after infection. After inoculation by an infected mosquito and incubation for three days, the infection is symptomatic in 75-95% of cases. There are three stages. The acute stage is characterized by the sudden onset of high fever associated with incapacitating distal polyarthralgia. Atypical, sometimes severe, manifestations are possible: neurological, digestive, cardiac, hepatic, dermatological, hematological, pulmonary and renal. These atypical forms are most often observed at extreme ages and in people with chronic diseases. The post-acute stage (60-80% of cases, from the fourth week to the end of the third month) is characterized by persistent and polymorphic musculoskeletal manifestations. During the chronic stage (50% of cases from the fourth month onwards) two entities can be distinguished: chronic inflammatory rheumatism and musculoskeletal disorders. Management is symptomatic. It is based on a precise semiological analysis, attentive listening to the patient and a multidisciplinary approach.


Assuntos
Aedes , Artrite Reumatoide , Febre de Chikungunya , Vírus Chikungunya , Animais , Febre de Chikungunya/complicações , Febre de Chikungunya/diagnóstico , Febre de Chikungunya/transmissão , Doença Crônica , Humanos
6.
BMC Public Health ; 20(1): 1385, 2020 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-32912177

RESUMO

BACKGROUND: In El Salvador, Aedes aegypti mosquitoes transmitting Zika and other arboviruses use water storage containers as important oviposition sites. Promotion of water storage container cleaning is a key element of prevention programs. We explored community perceptions surrounding cleaning practices among pregnant women, male partners of pregnant women, and women likely to become pregnant. METHODS: Researchers conducted 11 focus groups and 12 in-depth interviews which included individual elicitations of Zika prevention measures practiced in the community. Focus group participants rated 18 images depicting Zika-related behaviors according to effectiveness and feasibility in the community context, discussed influencing determinants, voted on community intentions to perform prevention behaviors, and performed washbasin cleaning simulations. In-depth interviews with male partners of pregnant women used projective techniques with images to explore their perceptions on a subset of Zika prevention behaviors. RESULTS: General cleaning of the home, to ensure a healthy environment, was a strong community norm. In this context, participants gave water storage container cleaning a high rating, for both its effectiveness and feasibility. Participants were convinced that they cleaned their water storage containers effectively against Zika, but their actual skills were inadequate to destroy Aedes aegypti eggs. A further constraint was the schedule of water availability. Even during pregnancy, male partners rarely cleaned water storage containers because water became available in homes when they were at work. Furthermore, prevailing gender norms did not foster male participation in domestic cleaning activities. Despite these factors, many men were willing to provide substantial support with cleaning when their partners were pregnant, in order to protect their family. CONCLUSIONS: Behavior change programs for the prevention of Zika and other arboviruses need to improve community members' mosquito egg destruction skills rather than perpetuate the promotion of non-specific cleaning in and around the home as effective. Egg elimination must be clearly identified as the objective of water storage container maintenance and programs should highlight the effective techniques to achieve this goal. In addition, programs must build the skills of family members who support pregnant women to maintain the frequency of effective egg destruction in all water storage containers of the home.


Assuntos
Aedes/virologia , Conhecimentos, Atitudes e Prática em Saúde , Controle de Mosquitos/métodos , Abastecimento de Água , Água , Infecção por Zika virus/prevenção & controle , Zika virus , Adolescente , Adulto , Animais , El Salvador , Feminino , Grupos Focais , Humanos , Masculino , Pessoa de Meia-Idade , Gravidez , Pesquisa Qualitativa , Características de Residência , Adulto Jovem , Zika virus/crescimento & desenvolvimento , Infecção por Zika virus/transmissão , Infecção por Zika virus/virologia
7.
Pestic Biochem Physiol ; 170: 104686, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32980070

RESUMO

New insecticides are urgently needed for the control of arthropod vectors of public health diseases. As resistance to many insecticides used for the control of public health pests is ubiquitous, all available chemistries should be evaluated for their potential to effectively control both insecticide-susceptible and insecticide-resistant strains of mosquitoes. This study aimed to evaluate p-p'-difluoro-diphenyl-trichloroethane (DFDT) as a mosquito control technology and relate its activity to that of DDT. We found that topical DFDT was significantly less toxic than DDT to both pyrethroid-susceptible and pyrethroid-resistant strains of Anopheles gambiae and Aedes aegypti. Direct nervous system recording from Drosophila melanogaster CNS demonstrated that DFDT is approximately 10-times less potent than DDT at blocking nerve firing, which may explain its relatively lower toxicity. DFDT was shown to be at least 4500 times more vapor-active than DDT, with an LC50 in a vapor toxicity screening assay of 2.2 µg/cm2. Resistance to DFDT was assessed in two mosquito strains that possess target-site mutations in the voltage-gated sodium channel and upregulated metabolic activity. Resistance ratios for Akdr (An. gambiae) and Puerto Rico (Ae. aegypti) strains were 9.2 and 12.2, respectively. Overall, this study demonstrates that DFDT is unlikely to be a viable public health vector control insecticide.


Assuntos
Aedes/efeitos dos fármacos , Inseticidas/farmacologia , Inseticidas/toxicidade , Piretrinas/toxicidade , Animais , Compostos de Bifenilo , DDT/toxicidade , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/genética , Resistência a Inseticidas/efeitos dos fármacos , Mosquitos Vetores , Porto Rico , Tricloroetanos
8.
Pestic Biochem Physiol ; 170: 104666, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32980073

RESUMO

Despite the substantial progress achieved in the characterization of cytochrome P450 (CYP) -based resistance mechanisms in mosquitoes, a number of questions remain unanswered. These include: (i) the regulation and physiology of resistance conferring CYPs; (ii) the actual contribution of CYPs in resistance alone or in combination with other detoxification partners or other resistance mechanisms; (iii) the association between overexpression levels and allelic variation, with the catalytic activity and the intensity of resistance and (iv) the true value of molecular diagnostics targeting CYP markers, for driving decision making in the frame of Insecticide Resistance Management applications. Furthermore, the translation of CYP - based insecticide resistance research in mosquitoes into practical applications, is being developed, but it is not fully exploited, as yet. Examples include the production of high throughput platforms for screening the liability (stability) or inhibition potential of novel insecticidal leads and synergists (add-ons), as well as the exploration of the negative cross resistance concept (i.e. detoxification of certain insecticides, but activation of others pro-insecticides). The goal of this review is to critically summarise the current knowledge and the gaps of the CYP-based metabolic insecticide resistance in Anopheles and Aedes mosquito vectors. The progress and limitations of the protein and the reverse/forward genetic approaches, the understanding and importance of molecular and physiological aspects, as well as the current and future exploitation routes of CYP research are discussed.


Assuntos
Aedes/efeitos dos fármacos , Aedes/genética , Anopheles/efeitos dos fármacos , Anopheles/genética , Inseticidas/farmacologia , Piretrinas , Animais , Sistema Enzimático do Citocromo P-450/genética , Resistência a Inseticidas/efeitos dos fármacos , Resistência a Inseticidas/genética , Mosquitos Vetores/genética
9.
Recurso na Internet em Português | LIS - Localizador de Informação em Saúde | ID: lis-47762

RESUMO

Trata-se do projeto que utiliza como estratégia a instalação de Estações Disseminadoras de Larvicida (EDs) como alternativa no controle de mosquitos Aedes aegypti e Ae. albopictus, transmissores dos vírus da dengue, zika e chikungunya.


Assuntos
Aedes , Controle de Vetores
10.
Sci Total Environ ; 739: 140336, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32758966

RESUMO

Dengue fever is mosquito borne viral disease caused by dengue virus and transmitted by Aedes mosquitoes. In recent years the dengue has spread rapidly to several regions and it becomes a major public health menace globally. Dengue transmission is strongly influenced by environmental factors such as temperature and rainfall. In the present study, a climate driven dengue model was developed and predicted areas vulnerable for dengue transmission under the present and future climate change scenarios in India. The study also projected the dengue distribution risk map using representative concentration pathways (RCP4.5 and RCP8.5) in India in 2018-2030 (forthcoming period), 2031-2050 (intermediate period) and 2051-2080 (long period). The dengue cases assessed in India from 1998 to 2018 and found that the dengue transmission is gradually increasing year over year. The temperature data from 1980 to 2017 shows that, the mean temperatures are raising in the Southern region of India. During 2000-2017 periods the dengue transmission is steadily increasing across the India in compare with 1980-1999 periods. The dengue distribution risk is predicted and it is revealed that the coastal states have yearlong transmission possibility, but the high transmission potential is observed throughout the monsoon period. Due to the climate change, the expansion two more months of dengue transmission risk occurs in many regions of India. Both RCP4.5 and RCP8.5 scenarios revealed that dengue outbreaks might occur at larger volume in Southern, Eastern, and Central regions of India. Furthermore a sensitivity analysis was performed to explore the impact of climate change on dengue transmission. These results helps to suggest appropriate control measures should be implemented to limit the spread in future warmer climates. Besides these, a proper plan is required to mitigate greenhouse gas emissions to reduce the epidemic potential of dengue in India.


Assuntos
Aedes , Dengue/epidemiologia , Animais , Mudança Climática , Surtos de Doenças , Índia
11.
PLoS Negl Trop Dis ; 14(8): e0008615, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32813707

RESUMO

The mosquito microbiome alters the physiological traits of medically important mosquitoes, which can scale to impact how mosquito populations sustain disease transmission. The mosquito microbiome varies significantly within individual mosquitoes and among populations, however the ecological and environmental factors that contribute to this variation are poorly understood. To further understand the factors that influence variation and diversity of the mosquito microbiome, we conducted a survey of the bacterial microbiome in the medically important mosquito, Aedes albopictus, on the high Pacific island of Maui, Hawai'i. We detected three bacterial Phyla and twelve bacterial families: Proteobacteria, Acitinobacteria, and Firmicutes; and Anaplasmataceae, Acetobacteraceae, Enterobacteriaceae, Burkholderiaceae, Xanthobacteraceae, Pseudomonadaceae, Streptomycetaceae, Staphylococcaceae, Xanthomonadaceae, Beijerinckiaceae, Rhizobiaceae, and Sphingomonadaceae. The Ae. albopictus bacterial microbiota varied among geographic locations, but temperature and rainfall were uncorrelated with this spatial variation. Infection status with an ampicomplexan pathosymbiont Ascogregarina taiwanensis was significantly associated with the composition of the Ae. albopictus bacteriome. The bacteriomes of mosquitoes with an A. taiwanensis infection were more likely to include several bacterial symbionts, including the most abundant lineage of Wolbachia sp. Other symbionts like Asaia sp. and several Enterobacteriaceae lineages were less prevalent in A. taiwanensis-infected mosquitoes. This highlights the possibility that inter- and intra-domain interactions may structure the Ae. albopictus microbiome.


Assuntos
Aedes/microbiologia , Aedes/parasitologia , Bactérias/classificação , Microbiota/fisiologia , Infecções Protozoárias em Animais/microbiologia , Doenças dos Animais , Animais , Apicomplexa , Bactérias/genética , Interações Hospedeiro-Parasita , Larva/microbiologia , Larva/parasitologia , Simbiose
12.
PLoS One ; 15(8): e0234892, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32817668

RESUMO

The mosquito Aedes aegypti vectors the arboviral diseases yellow fever, dengue, Zika and chikungunya. Larvae are usually found developing in freshwater; however, more recently they have been increasingly found in brackish water, potential habitats which are traditionally ignored by mosquito control programs. Aedes aegypti larvae are osmo-regulators maintaining their hemolymph osmolarity in a range of ~ 250 to 300 mOsmol l-1. In freshwater, the larvae must excrete excess water while conserving ions while in brackish water, they must alleviate an accumulation of salts. The compensatory physiological mechanisms must involve the transport of ions and water but little is known about the water transport mechanisms in the osmoregulatory organs of these larvae. Water traverses cellular membranes predominantly through transmembrane proteins named aquaporins (AQPs) and Aedes aegypti possesses 6 AQP homologues (AaAQP1 to 6). The objective of this study was to determine if larvae that develop in freshwater or brackish water have differential aquaporin expression in osmoregulatory organs, which could inform us about the relative importance and function of aquaporins to mosquito survival under these different osmotic conditions. We found that AaAQP transcript abundance was similar in organs of freshwater and brackish water mosquito larvae. Furthermore, in the Malpighian tubules and hindgut AaAQP protein abundance was unaffected by the rearing conditions, but in the gastric caeca the protein level of one aquaporin, AaAQP1 was elevated in brackish water. We found that AaAQP1 was expressed apically while AaAQP4 and AaAQP5 were found to be apical and/or basal in the epithelia of osmoregulatory organs. Overall, the results suggest that aquaporin expression in the osmoregulatory organs is mostly consistent between larvae that are developing in freshwater and brackish water. This suggests that aquaporins may not have major roles in adapting to longterm survival in brackish water or that aquaporin function may be regulated by other mechanisms like post-translational modifications.


Assuntos
Aedes/genética , Aquaporinas/genética , Osmorregulação/genética , Aedes/fisiologia , Animais , Aquaporinas/metabolismo , Infecções por Arbovirus , Transporte Biológico , Ecossistema , Água Doce , Expressão Gênica/genética , Regulação da Expressão Gênica/genética , Hemolinfa/metabolismo , Proteínas de Insetos/metabolismo , Larva/genética , Larva/metabolismo , Osmorregulação/fisiologia , Osmose , Águas Salinas , Salinidade , Água/metabolismo
13.
PLoS One ; 15(8): e0228975, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32817690

RESUMO

In mosquitoes of medical importance, wing shape and size can vary with altitude, an aspect that can influence dispersion and, consequently, their vector capacity. Using geometric morphometry analysis, Aedes aegypti wing size and shape variation of males and females was studied in four altitudes in the second-smallest department in Colombia: 1,200 m (Tebaida), 1,400 m (Armenia), 1,500 m (Calarcá), and 1,700 m (Filandia). Wing shape in males (P < 0.001) and females (P < 0.001) was significantly different through the altitudinal gradient; in turn, wing size in males followed the altitudinal gradient males (R2 = 0.04946, P = 0.0002), females (R2 = 0.0011, P = 0.46). Wing allometry for males (P < 0.001) and females (P < 0.001) was significant. Likewise, the shape and size of the wings of males (P < 0.001) and females (P < 0.001) had significant fluctuating asymmetry. It is concluded that, in a small scale with an altitudinal variation of 500 meters, it is detected that the size and shape of the wings varied in A. aegypti, main vector the agents that cause dengue, chikungunya, and Zika. The fluctuating asymmetry is present in the individuals studied and could be associated with environmental effects caused by vector control campaigns present in some sampling locations.


Assuntos
Aedes/fisiologia , Asas de Animais/anatomia & histologia , Asas de Animais/fisiologia , Altitude , Animais , Febre de Chikungunya , Colômbia , Dengue , Feminino , Masculino , Mosquitos Vetores/anatomia & histologia , Infecção por Zika virus
14.
PLoS Negl Trop Dis ; 14(8): e0008541, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32764758

RESUMO

In 2019, dengue incidences increased dramatically in many countries. However, the prospective growth in dengue incidence did not occur in Guangzhou, China. We examined the effectiveness of early start of Grade III response to dengue in Guangzhou. We extracted the data on daily number of dengue cases during 2017-2019 in Guangzhou and weekly data for Foshan and Zhongshan from the China National Notifiable Disease Reporting System, while the data on weekly number of positive ovitraps for adult and larval Aedes albopictus were obtained from Guangzhou Center for Disease Control and Prevention. We estimated the number of dengue cases prevented by bringing forward the starting time of Grade III response from September in 2017-2018 to August in 2019 in Guangzhou using a quasi-Poisson regression model and applied the Baron and Kenny's approach to explore whether mosquito vector density was a mediator of the protective benefit. In Guangzhou, early start of Grade III response was associated with a decline in dengue incidence (relative risk [RR]: 0.54, 95% confidence interval [CI]: 0.43-0.70), with 987 (95% CI: 521-1,593) cases averted in 2019. The rate of positive ovitraps also significantly declined (RR: 0.64, 95% CI: 0.53-0.77). Moreover, both mosquito vector density and early start of Grade III response was significantly associated with dengue incidence after adjustment for each other. By comparing with the incidence in Foshan and Zhongshan where the Grade III response has not been taken, benefits from the response starting in August were confirmed but not if starting from September. Early start of Grade III response has effectively mitigated the dengue burden in Guangzhou, China, which might be partially through reducing the mosquito vector density. Our findings have important public health implications for development and implementation of dengue control interventions for Guangzhou and other locations with dengue epidemics.


Assuntos
Aedes/fisiologia , Dengue/epidemiologia , Mosquitos Vetores/fisiologia , Adulto , Aedes/virologia , Animais , China/epidemiologia , Surtos de Doenças/prevenção & controle , Humanos , Incidência , Larva , Modelos Biológicos , Mosquitos Vetores/virologia
15.
PLoS Negl Trop Dis ; 14(8): e0008528, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32764763

RESUMO

House Index, Container Index, and Breteau Index are the most commonly used indices for dengue vector surveillance. However, these larval indices are a poor proxy for measuring the adult population-which is responsible for disease transmission. Information on the adult distribution and density are important for assessing transmission risk as well as for developing effective control strategies. This study introduces a new entomological index, Gravitrap aegypti index (GAI), which estimates the adult female Aedes aegypti population in the community and presents its association with dengue cases. Gravitraps were deployed across 34 treatment sites in Singapore from September 2013 to September 2016. The GAI, derived from the Gravitrap surveillance data, was analysed to investigate the spatio-temporal patterns of the Ae. aegypti population in Singapore. The index was further categorised into low, moderate, and high-risk groups and its association with dengue cases were examined. A Before-After Control Impact analysis was performed to evaluate the epidemiology impact of Gravitrap system on dengue transmission. The Ae. aegypti population exhibits a seasonal pattern, and spatial heterogeneity in Ae. aegypti abundance was observed among treatment sites. The Ae. aegypti population was also found to be unevenly distributed among floors of an apartment block, with low floors (floors 1-4) having a higher abundance of mosquitoes trapped than mid (floors 5-8) and high (floors ≥9) floors. Areas with high GAI were shown to have higher dengue case count. Gravitrap has also demonstrated to be a good dengue control tool. The contribution of cases by treatment sites to the national numbers was lower after Gravitraps deployment. The GAI, which is of better relevance to dengue transmission risk, could be recommended as an indicator for decision making in vector control efforts, and to monitor the spatio-temporal variability of the adult Aedes population in the country. In addition, findings from this study indicate that Gravitraps can be used as a dengue control tool to reduce dengue transmission.


Assuntos
Aedes/fisiologia , Surtos de Doenças/prevenção & controle , Controle de Mosquitos/instrumentação , Controle de Mosquitos/métodos , Aedes/virologia , Animais , Dengue/epidemiologia , Vírus da Dengue , Meio Ambiente , Feminino , Insetos Vetores , Densidade Demográfica , Singapura
16.
PLoS Negl Trop Dis ; 14(8): e0008605, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32797109

RESUMO

In human communities inhabiting areas-such as West Bengal- India-where perpetuate the pre-imago & adult developmental stages of mosquitoes; many infectious diseases are still diagnosed such as Dengue, Malaria and Acute Encephalitis Syndrome. The control of the aquatic developmental stages is one of the easiest way to prevent the emergence of adults-the blood feeding adult females being thus prevented to sample their blood meal and to lay their eggs in the aquatic milieu where develop the aquatic pre-imaginal developmental stages. Moreover, reducing the adult population size also the probability of for the blood feeding adult female mosquitoes to act as hosts and vectors of the arboviruses such as dengue virus & Japanese encephalitis virus as well as of Plasmodium. Several environmental factors including water quality parameters are responsible for the selection of oviposition sites by the female mosquitoes. In our study, larval densities of three important mosquitoes (Aedes/A. albopictus, Anopheles/An. stephensi and Culex/C. vishnui) were measured and water qualities of their habitat i.e. pH, Specific Conductance, Dissolved Oxygen, Chemical Oxygen Demand, Total alkalinity (Talk), Hardness, Nitrate nitrogen and Ammonia nitrogen were analyzed in 2017 and 2018 in many districts of West Bengal where humans beings are suffering from arboviruses and /or malaria. Whereas we have found positive correlation of density of C. vishnui and A. albopictus with the water factors except Chemical Oxygen Demand (COD) and Talk, for An. stephensi all these factors except pH, COD and Talk have positive correlation. Hardness of the water shows positive correlation with the density of An. stephensi and C. vishnui but negative correlation with density of A. albopictus. Contour plot analysis demonstrates that occurrence of each mosquito species lies in between specific range of water factors. Inter- correlation analysis revealed that mosquitoes were negatively correlated with each other. A positive correlation of the water quality parameters and larval density, over two successive years, was also noticed. In conclusion, the increasing level of pollution due to industrial and other irresponsible waste management system which changes the water quality parameters may also influence mosquito population.


Assuntos
Ecossistema , Controle de Mosquitos , Mosquitos Vetores/fisiologia , Aedes/fisiologia , Animais , Anopheles/fisiologia , Arbovirus , Culex/fisiologia , Dengue/transmissão , Vírus da Encefalite Japonesa (Espécie) , Encefalite Japonesa/transmissão , Feminino , Humanos , Concentração de Íons de Hidrogênio , Índia , Larva , Modelos Logísticos , Malária/transmissão , Mosquitos Vetores/parasitologia , Mosquitos Vetores/virologia , Análise Multivariada , Densidade Demográfica , Água
17.
Mem Inst Oswaldo Cruz ; 115: e200284, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32785481

RESUMO

The coronavirus disease of 2019 (COVID-19) pandemic challenges public health systems around the world. Tropical countries will face complex epidemiological scenarios involving the simultaneous transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with viruses transmitted by Aedes aegypti. The occurrence of arboviral diseases with COVID-19 in the Latin America and the Caribbean (LAC) region presents challenges and opportunities for strengthening health services, surveillance and control programs. Financing of training, equipment and reconversion of hospital spaces will have a negative effect on already the limited resource directed to the health sector. The strengthening of the diagnostic infrastructure reappears as an opportunity for the national reference laboratories. Sharing of epidemiological information for the modeling of epidemiological scenarios allows collaboration between health, academic and scientific institutions. The fear of contagion by COVID-19 is constraining people with arboviral diseases to search for care which can lead to an increase in serious cases and could disrupt the operation of vector-control programs due to the reluctance of residents to open their doors to health personnel. Promoting intense community participation along with the incorporation of long lasting innovations in vector control offers new opportunities for control. The COVID-19 pandemic offers challenges and opportunities that must provoke positive behavioral changes and encourage more permanent self-care actions.


Assuntos
Aedes/microbiologia , Aedes/virologia , Infecções por Coronavirus , Coronavirus , Dengue/prevenção & controle , Pandemias , Pneumonia Viral , Febre Amarela/prevenção & controle , América , Animais , Betacoronavirus , Região do Caribe , Infecções por Coronavirus/epidemiologia , Humanos , Mosquitos Vetores , Pneumonia Viral/epidemiologia
18.
Environ Pollut ; 266(Pt 3): 115275, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32771866

RESUMO

Pharmaceuticals and personal care products (PPCPs) are a class of emerging contaminants commonly detected in environmental waters worldwide. Although reports about their detection in aquatic environments are increasing, limited studies show their effects on holometabolous insects. In this study, acute and chronic exposure to naproxen (0.02, 41, 82, 164, 382, 656, and 1312 mg L-1) and propylparaben (0.02, 25, 50, 100, 250, 500, and 1000 mg L-1) were evaluated in Aedes aegypti L. Acute exposure to naproxen (≥0.02 mg L-1) and propylparaben (≥0.02 mg L-1) reduced egg eclosion. Propylparaben (≥250 mg L-1) caused significant larval mortality but naproxen did not even at the highest experimental concentration used. LC50 for naproxen and propylparaben in larvae were 1100 mg L-1 and 182.6 mg L-1, respectively. Naproxen (≥0.02 mg L-1) and propylparaben (≥0.02 mg L-1) reduced pupation. Emergence was also reduced by naproxen (≥164 mg L-1) and propylparaben (≥0.02 mg L-1). The fecundity of females was significantly reduced due to chronic exposure to naproxen (≥0.02 mg L-1). There was also a reduction in the fecundity of females due to chronic propylparaben exposure but it was statistically insignificant in the concentrations used. In the F1 generation eggs, only 100 mg L-1 propylparaben reduced eclosion. Eclosion and larval survival were sensitive to acute exposure, particularly to propylparaben. The reduced pupation and emergence indicated a delay in the progression of the life cycle. Chronic exposure also indicated a reduction in fecundity. F1 eggs exhibited tolerance to the negative effect of subsequent exposure. Our findings suggest that propylparaben can affect Ae. aegypti more negatively than naproxen.


Assuntos
Aedes , Animais , Feminino , Larva , Estágios do Ciclo de Vida , Naproxeno , Parabenos
20.
PLoS Negl Trop Dis ; 14(8): e0008428, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32853197

RESUMO

Vector-borne diseases are a major cause of morbidity and mortality worldwide. Aedes-borne diseases, in particular, including dengue, chikungunya, yellow fever, and Zika, are increasing at an alarming rate due to urbanisation, population movement, weak vector control programmes, and climate change. The World Health Organization calls for strengthening of vector control programmes in line with the Global Vector Control Response (GVCR) strategy, and many vector control programmes are transitioning to this new approach. The Singapore dengue control programme, situated within the country's larger vision of a clean, green, and sustainable environment for the health and well-being of its citizens, provides an excellent example of the GVCR approach in action. Since establishing vector control operations in the 1960s, the Singapore dengue control programme succeeded in reducing the dengue force of infection 10-fold by the 1990s and has maintained it at low levels ever since. Key to this success is consideration of dengue as an environmental disease, with a strong focus on source reduction and other environmental management methods as the dominant vector control strategy. The programme collaborates closely with other government ministries, as well as town councils, communities, the private sector, and academic and research institutions. Community engagement programmes encourage source reduction, and house-to-house inspections accompanied by a strong legislative framework with monetary penalties help to support compliance. Strong vector and epidemiological surveillance means that routine control activities can be heightened to specifically target dengue clusters. Despite its success, the programme continues to innovate to tackle challenges such as climate change, low herd immunity, and manpower constraints. Initiatives include development of novel vector controls such as Wolbachia-infected males and spatiotemporal models for dengue risk assessment. Lessons learnt from the Singapore programme can be applied to other settings, even those less well-resourced than Singapore, for more effective vector control.


Assuntos
Dengue/prevenção & controle , Controle de Mosquitos/métodos , Controle de Mosquitos/organização & administração , Aedes/virologia , Animais , Participação da Comunidade , Dengue/epidemiologia , Humanos , Mosquitos Vetores/virologia , Singapura/epidemiologia
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