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1.
Cochrane Database Syst Rev ; 4: CD015636, 2024 Apr 10.
Article in English | MEDLINE | ID: mdl-38597256

ABSTRACT

BACKGROUND: Dengue is a global health problem of high significance, with 3.9 billion people at risk of infection. The geographic expansion of dengue virus (DENV) infection has resulted in increased frequency and severity of the disease, and the number of deaths has increased in recent years. Wolbachia,an intracellular bacterial endosymbiont, has been under investigation for several years as a novel dengue-control strategy. Some dengue vectors (Aedes mosquitoes) can be transinfected with specific strains of Wolbachia, which decreases their fitness (ability to survive and mate) and their ability to reproduce, inhibiting the replication of dengue. Both laboratory and field studies have demonstrated the potential effect of Wolbachia deployments on reducing dengue transmission, and modelling studies have suggested that this may be a self-sustaining strategy for dengue prevention, although long-term effects are yet to be elucidated. OBJECTIVES: To assess the efficacy of Wolbachia-carrying Aedes speciesdeployments (specifically wMel-, wMelPop-, and wAlbB- strains of Wolbachia) for preventing dengue virus infection. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, four other databases, and two trial registries up to 24 January 2024. SELECTION CRITERIA: Randomized controlled trials (RCTs), including cluster-randomized controlled trials (cRCTs), conducted in dengue endemic or epidemic-prone settings were eligible. We sought studies that investigated the impact of Wolbachia-carrying Aedes deployments on epidemiological or entomological dengue-related outcomes, utilizing either the population replacement or population suppression strategy. DATA COLLECTION AND ANALYSIS: Two review authors independently selected eligible studies, extracted data, and assessed the risk of bias using the Cochrane RoB 2 tool. We used odds ratios (OR) with the corresponding 95% confidence intervals (CI) as the effect measure for dichotomous outcomes. For count/rate outcomes, we planned to use the rate ratio with 95% CI as the effect measure. We used adjusted measures of effect for cRCTs. We assessed the certainty of evidence using GRADE. MAIN RESULTS: One completed cRCT met our inclusion criteria, and we identified two further ongoing cRCTs. The included trial was conducted in an urban setting in Yogyakarta, Indonesia. It utilized a nested test-negative study design, whereby all participants aged three to 45 years who presented at healthcare centres with a fever were enrolled in the study provided they had resided in the study area for the previous 10 nights. The trial showed that wMel-Wolbachia infected Ae aegypti deployments probably reduce the odds of contracting virologically confirmed dengue by 77% (OR 0.23, 95% CI 0.15 to 0.35; 1 trial, 6306 participants; moderate-certainty evidence). The cluster-level prevalence of wMel Wolbachia-carrying mosquitoes remained high over two years in the intervention arm of the trial, reported as 95.8% (interquartile range 91.5 to 97.8) across 27 months in clusters receiving wMel-Wolbachia Ae aegypti deployments, but there were no reliable comparative data for this outcome. Other primary outcomes were the incidence of virologically confirmed dengue, the prevalence of dengue ribonucleic acid in the mosquito population, and mosquito density, but there were no data for these outcomes. Additionally, there were no data on adverse events. AUTHORS' CONCLUSIONS: The included trial demonstrates the potential significant impact of wMel-Wolbachia-carrying Ae aegypti mosquitoes on preventing dengue infection in an endemic setting, and supports evidence reported in non-randomized and uncontrolled studies. Further trials across a greater diversity of settings are required to confirm whether these findings apply to other locations and country settings, and greater reporting of acceptability and cost are important.


Subject(s)
Aedes , Dengue Virus , Dengue , Wolbachia , Animals , Humans , Aedes/microbiology , Mosquito Vectors/microbiology , Dengue/prevention & control
3.
J Prev Med Public Health ; 57(2): 176-184, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38576201

ABSTRACT

OBJECTIVES: The dengue prevention program known as "One House One Mosquito Larva Inspector" involves health volunteers who play a crucial role in the surveillance of mosquito larvae and reporting their findings to local public health officials. This study aimed to identify factors related to the knowledge, attitudes, and practices (KAP) of dengue prevention behavior among these health volunteers. METHODS: A study was conducted in 5 sub-districts in Malang, an urban area in Indonesia. We employed a cross-sectional design and utilized a semi-structured questionnaire to assess the KAP of 400 health volunteers. Data were collected through face-to-face interviews. RESULTS: Multiple logistic regression analysis revealed that individuals with a more positive attitude (odds ratio [OR], 1.69; p<0.05) and those with family sizes greater than five persons (OR, 1.90; p<0.05) were more likely to engage in effective dengue prevention practices. Additionally, possesing good knowledge was significantly assocated with more positive attitude (OR, 2.24; p<0.001). Furthermore, 40% reduction in positive attitude was observed in those over 45 years (OR, 0.60; p<0.05). The best practices most frequently reported by the majority of respondents included always reporting their surveillance activities (75.8%) and cleaning the water container in the bathroom at least once a week (65.2%). However, only 52.2% of respondents regularly checked for mosquito larvae in their neighborhood. CONCLUSIONS: Sustainable promotion and training for the "One House One Mosquito Larva Inspector" initiative are necessary, particularly among young health volunteers, to improve dengue prevention behaviors both within their own homes and in the surrounding environment.


Subject(s)
Dengue , Animals , Humans , Dengue/prevention & control , Dengue/epidemiology , Indonesia/epidemiology , Health Knowledge, Attitudes, Practice , Cross-Sectional Studies , Surveys and Questionnaires , Volunteers
4.
Hum Vaccin Immunother ; 20(1): 2323264, 2024 Dec 31.
Article in English | MEDLINE | ID: mdl-38599678

ABSTRACT

Dengvaxia is the first dengue vaccine recommended in the United States (U.S.). It is recommended for children aged 9-16 y with laboratory-confirmed previous dengue infection and living in areas where dengue is endemic. We conducted focus groups with parents and in-depth interviews with key informants (i.e. practicing pediatricians, physicians from immunization clinics, university researchers, and school officials) in Puerto Rico (P.R.) to examine acceptability, barriers, and motivators to vaccinate with Dengvaxia. We also carried out informal meetings and semi-structured interviews to evaluate key messages and educational materials with pediatricians and parents. Barriers to vaccination included lack of information, distrust toward new vaccines, vaccine side effects and risks, and high cost of/lack of insurance coverage for laboratory tests and vaccines. Motivators included clear information about the vaccine, a desire to prevent future dengue infections, the experience of a previous dengue infection or awareness of dengue fatality, vaccine and laboratory tests covered by health insurance, availability of rapid test results and vaccine appointments. School officials and parents agreed parents would pay a deductible of $5-20 for Dengvaxia. For vaccine information dissemination, parents preferred an educational campaign through traditional media and social media, and one-on-one counseling of parents by healthcare providers. Education about this vaccine to healthcare providers will help them answer parents' questions. Dengvaxia acceptability in P.R. will increase by addressing motivators and barriers to vaccination and by disseminating vaccine information in plain language through spokespersons from health institutions in P.R.


Subject(s)
Dengue Vaccines , Dengue , Vaccines , Child , Humans , Dengue/prevention & control , Dengue Vaccines/adverse effects , Parents , Puerto Rico/epidemiology , United States , Vaccination/methods , Adolescent
5.
Hum Vaccin Immunother ; 20(1): 2337985, 2024 Dec 31.
Article in English | MEDLINE | ID: mdl-38602074

ABSTRACT

Insect vector-borne diseases (VBDs) pose significant global health challenges, particularly in tropical and subtropical regions. The WHO has launched the "Global Vector Control Response (GVCR) 2017-2030" to address these diseases, emphasizing a comprehensive approach to vector control. This systematic review investigates the potential of malaria and dengue vaccines in controlling mosquito-borne VBDs, aiming to alleviate disease burdens and enhance public health. Following PRISMA 2020 guidelines, the review incorporated 39 new studies out of 934 identified records. It encompasses various studies assessing malaria and dengue vaccines, emphasizing the significance of vaccination as a preventive measure. The findings indicate variations in vaccine efficacy, duration of protection, and safety considerations for each disease, influencing public health strategies. The review underscores the urgent need for vaccines to combat the increasing burden of VBDs like malaria and dengue, advocating for ongoing research and investment in vaccine development.


Subject(s)
Dengue Vaccines , Dengue , Malaria , 60509 , Animals , Dengue/prevention & control , Malaria/prevention & control , Public Health , Humans
7.
Med J Malaysia ; 79(Suppl 1): 203-208, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38555906

ABSTRACT

INTRODUCTION: Dengue fever, a vector borne disease transmitted primarily by Aedes albopictus and Aedes aegypti mosquitoes, has triggered a significant global resurgence. While many vector control programs depend on the use of chemical insecticides to curb outbreaks, its heavy reliance raises environmental concerns and the risk of insecticide resistance. Alternatively, botanically derived insecticidal agents with larvicidal properties offer an ecofriendlier option. This review aims to analyze scientific reports that described the effectiveness of plant-derived extracts for vector control. MATERIALS AND METHODS: A literature search was performed to analyze studies that focused on plant-based extracts used for larvicidal purposes using databases such as Science Direct. Springer, PubMed, and Scopus. The inclusion criteria for publications were larvicidal effects, published in English from the year 2017 and availability of full-text articles. The available literature was further characterized by the value of larvicidal activities of LC50 and LC90 (< 50 ppm), of 22 different parts of plant species from 7 plant families namely Apiaceae, Asteraceae, Lauraceae, Magnoliaceae, Myrtaceae, Piperaceae and Rubiaceae. RESULTS: When comparing the values of LC50, 12 plants species (Artemisia vulgaris, Crassocephalum crepidioides, Echinops grijsii, Melaleuca leucadendra, Neolitsea ellipsoidea, Pavetta tomentosa, Piper betle, Piper caninum, Piper Montium, Piper muntabile, Piper ovatum, Tarenna asiatica) showed promising larvicidal efficacies with LC50 < 10 ppm. CONCLUSION: This review emphasizes the effective alternatives of plant extracts for the potential production of larvicides. Piper betle extract and chloroform extract of Tarenna asiatica reported the most significant larvicidal activity (LC50 < 1 ppm) against mosquito vectors. Further reviews focusing on the mode of actions of its phytochemically constituents are essential for the future development of potentially significant plant-based larvicides.


Subject(s)
Aedes , Dengue , Insecticides , Animals , Dengue/prevention & control , Insecticides/pharmacology , Insecticides/chemistry , Larva , Mosquito Vectors , Plant Extracts/pharmacology
8.
BMJ Open ; 14(3): e074222, 2024 Mar 12.
Article in English | MEDLINE | ID: mdl-38479731

ABSTRACT

OBJECTIVES: To use a community-based participatory research (CBPR) design to explore local community behaviours and stakeholders' challenges in engaging communities in dengue prevention behaviours in Hulu Langat, Selangor, Malaysia. DESIGN: This CBPR design in implementation comprised in-depth interviews (IDIs) and focus group discussions (FGDs). Themes were identified from the data with inductive and deductive thematic analysis. SETTING: FGDs were conducted in local community areas and IDIs were conducted in the local authority (LA) office and the Hulu Langat district health office. PARTICIPANTS: All FGD and IDI participants consented to the study, and included health authorities (n=4), LAs (n=7), community leader (n=1), faith leader (n=1), patients diagnosed with dengue (IDIs, n=2) and permanent residents of Hulu Langat who had been exposed to dengue infectious disease (FGDs, n=27). RESULTS: The main themes were categorised into community behaviour and stakeholder challenges. The community behaviour-related themes were awareness of dengue disease and Aedes mosquitoes, perception of risk and severity, and involvement of authorities. The themes related to stakeholder challenges were resource constraints and capacity issues, jurisdictional constraints and coordination, and educational dissemination and vandalism. CONCLUSIONS: The actions of the authorities shape community and stakeholder behaviours. Effective communication, including clear and aesthetically pleasing messages, motivates individuals to take appropriate actions. It is crucial for the authorities to engage in inclusive communication and consider diverse perspectives, such as those of residents and individuals exposed to dengue infection. Authorities that provide accurate and unbiased information foster transparency and enable informed decision-making by all stakeholders.


Subject(s)
Community-Based Participatory Research , Dengue , Animals , Humans , Malaysia , Qualitative Research , Focus Groups , Dengue/prevention & control
9.
Front Public Health ; 12: 1361717, 2024.
Article in English | MEDLINE | ID: mdl-38528862

ABSTRACT

Background: Over the past few decades, the incidence of dengue fever has considerably increased. Effective vector control strategies and specific protection using dengue vaccine are thought to be the key elements to combat dengue. The dengue incidence among the Singapore youths (15-24 years) was second only to that of adults (25-44 years). This study evaluated the knowledge and attitude of Singapore youths on dengue and its preventive measures. Methods: A cross-sectional study using online-based questionnaire survey was conducted among Singapore youths from September to November 2022. Data were analyzed for descriptive statistics whereas Chi-squared test, linear regression analysis and Pearson correlation were used to determine the association between demographic factors and youth's attitude on dengue prevention using Rstudio. Results: A total of 624 respondents completed the survey out of 1822 surveys distributed nation-wide, with a response rate of 34.2% (mean age 17.4 years ± 1.84; 59.3% female; 89.9% Chinese). The mean dengue knowledge scores of participants were 14.1 ±2.8. Univariate analysis showed that teenagers (15-19 years) had significantly higher knowledge score than the young adults (20-24 years) (ß=0.82,95%CI = 0.13-1.51, p = 0.021). Majority of them were aware of the Mozzie Wipeout campaign (90.2%) followed by the release of Wolbachia mosquitos (69.1%). Two-thirds of the youths who were aware of Wolbachia and Gravitrap considered that it was effective in reducing dengue infection rates. Participants suggested information about the current dengue infection rate (71.9%) as the most effective of the five proposed strategies to improve uptake of dengue preventive measures. In comparison to young adults, teenagers were more likely to uptake dengue preventive measures if widespread mosquito control practices were implemented (69.1% vs. 42.3%). Conclusion: The overall knowledge of the youths on dengue and its prevention was satisfactory. Future health promotion campaigns targeting the youths should focus on transforming the knowledge into practice.


Subject(s)
Dengue , Literacy , Young Adult , Humans , Adolescent , Female , Male , Cross-Sectional Studies , Dengue/epidemiology , Dengue/prevention & control , Surveys and Questionnaires , Regression Analysis
10.
Front Immunol ; 15: 1282754, 2024.
Article in English | MEDLINE | ID: mdl-38444851

ABSTRACT

Introduction: Dengue virus infection is a global health problem lacking specific therapy, requiring an improved understanding of DENV immunity and vaccine responses. Considering the recent emerging of new dengue vaccines, here we performed an integrative systems vaccinology characterization of molecular signatures triggered by the natural DENV infection (NDI) and attenuated dengue virus infection models (DVTs). Methods and results: We analyzed 955 samples of transcriptomic datasets of patients with NDI and attenuated dengue virus infection trials (DVT1, DVT2, and DVT3) using a systems vaccinology approach. Differential expression analysis identified 237 common differentially expressed genes (DEGs) between DVTs and NDI. Among them, 28 and 60 DEGs were up or downregulated by dengue vaccination during DVT2 and DVT3, respectively, with 20 DEGs intersecting across all three DVTs. Enriched biological processes of these genes included type I/II interferon signaling, cytokine regulation, apoptosis, and T-cell differentiation. Principal component analysis based on 20 common DEGs (overlapping between DVTs and our NDI validation dataset) distinguished dengue patients by disease severity, particularly in the late acute phase. Machine learning analysis ranked the ten most critical predictors of disease severity in NDI, crucial for the anti-viral immune response. Conclusion: This work provides insights into the NDI and vaccine-induced overlapping immune response and suggests molecular markers (e.g., IFIT5, ISG15, and HERC5) for anti-dengue-specific therapies and effective vaccination development.


Subject(s)
Dengue , Vaccines , Virus Diseases , Humans , Vaccinology , Vaccination , Dengue/prevention & control
11.
Environ Microbiol ; 26(3): e16588, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38450576

ABSTRACT

Dengue represents an increasing public health burden worldwide. In Africa, underreporting and misdiagnosis often mask its true epidemiology, and dengue is likely to be both more widespread than reported data suggest and increasing in incidence and distribution. Wolbachia-based dengue control is underway in Asia and the Americas but has not to date been deployed in Africa. Due to the genetic heterogeneity of African Aedes aegypti populations and the complexity of the host-symbiont interactions, characterization of key parameters of Wolbachia-carrying mosquitoes is paramount for determining the potential of the system as a control tool for dengue in Africa. The wAlbB Wolbachia strain was stably introduced into an African Ae. aegypti population by introgression, and showed high intracellular density in whole bodies and different mosquito tissues; high intracellular density was also maintained following larval rearing at high temperatures. No effect on the adult lifespan induced by Wolbachia presence was detected. Moreover, the ability of this strain to strongly inhibit DENV-2 dissemination and transmission in the host was also demonstrated in the African background. Our findings suggest the potential of harnessing Wolbachia for dengue control for African populations of Ae. aegypti.


Subject(s)
Aedes , Dengue , Wolbachia , Animals , Burkina Faso/epidemiology , Wolbachia/genetics , Asia , Dengue/prevention & control
12.
Science ; 383(6687): 1042-1043, 2024 Mar 08.
Article in English | MEDLINE | ID: mdl-38452073

ABSTRACT

A locally produced vaccine did well in a phase 3 clinical trial but won't be available until at least 2025.


Subject(s)
Dengue Vaccines , Dengue , Humans , Brazil/epidemiology , Clinical Trials, Phase III as Topic , Dengue/prevention & control , Dengue Vaccines/therapeutic use , Vaccination
13.
PLoS One ; 19(3): e0299953, 2024.
Article in English | MEDLINE | ID: mdl-38457405

ABSTRACT

Dengue poses a significant and multifaceted public health challenge in Sri Lanka, encompassing both preventive and curative aspects. Accurate dengue incidence forecasting is pivotal for effective surveillance and disease control. To address this, we developed an Autoregressive Integrated Moving Average (ARIMA) model tailored for predicting weekly dengue cases in the Colombo district. The modeling process drew on comprehensive weekly dengue fever data from the Weekly Epidemiological Reports (WER), spanning January 2015 to August 2020. Following rigorous model selection, the ARIMA (2,1,0) model, augmented with an autoregressive component (AR) of order 16, emerged as the best-fitted model. It underwent initial calibration and fine-tuning using data from January 2015 to August 2020, and was validated against independent 2000 data. Selection criteria included parameter significance, the Akaike Information Criterion (AIC), and Schwarz Bayesian Information Criterion (SBIC). Importantly, the residuals of the ARIMA model conformed to the assumptions of randomness, constant variance, and normality affirming its suitability. The forecasts closely matched observed dengue incidence, offering a valuable tool for public health decision-makers. However, an increased percentage error was noted in late 2020, likely attributed to factors including potential underreporting due to COVID-19-related disruptions amid rising dengue cases. This research contributes to the critical task of managing dengue outbreaks and underscores the dynamic challenges posed by external influences on disease surveillance.


Subject(s)
Dengue , Humans , Dengue/epidemiology , Dengue/prevention & control , Incidence , Sri Lanka/epidemiology , Bayes Theorem , Models, Statistical , Public Health , Forecasting
14.
PLoS Negl Trop Dis ; 18(3): e0012060, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38551892

ABSTRACT

The 6th Asia Dengue Summit (ADS) themed "Road Map to Zero Dengue Death" was held in Thailand from 15th-16th June 2023. The summit was hosted by Tropical Medicine Cluster, Chulalongkorn University, Bangkok, Thailand in conjunction with Queen Saovabha Memorial Institute, The Thai Red Cross Society; Faculty of Tropical Medicine, Mahidol University; and the Ministry of Public Health. The 6th ADS was convened by Asia Dengue Voice and Action (ADVA); Global Dengue and Aedes Transmitted Diseases Consortium (GDAC); Southeast Asian Ministers of Education Tropical Medicine and Public Health Network (SEAMEO TROPMED); Fondation Mérieux (FMx) and the International Society for Neglected Tropical Diseases (ISNTD). Dengue experts from academia and research, and representatives from the Ministries of Health, Regional and Global World Health Organization (WHO) and International Vaccine Institute (IVI) participated in the three-day summit. With more than 51 speakers and 451 delegates from over 24 countries, 10 symposiums, and 2 full days, the 6th ADS highlighted the growing threat of dengue and its antigenic evolution, flagged the urgent need to overcome vaccine hesitancy and misinformation crisis, and focused on dengue control policies, newer diagnostics, therapeutics and vaccines, travel-associated dengue, and strategies to improve community involvement.


Subject(s)
Dengue , Travel , Humans , Thailand , Public Health , World Health Organization , Dengue/epidemiology , Dengue/prevention & control , Asia, Southeastern/epidemiology
15.
Microbiol Spectr ; 12(4): e0012824, 2024 Apr 02.
Article in English | MEDLINE | ID: mdl-38483475

ABSTRACT

Two Wolbachia strains, wMel and wAlbB, have been transinfected into Aedes aegypti mosquitoes for population replacement with the aim of reducing dengue transmission. Epidemiological data from various endemic sites suggest a pronounced decrease in dengue transmission after implementing this strategy. In this study, we investigated the impact of the Wolbachia strains wMel and wAlbB on Ae. aegypti fitness in a common genetic background. We found that Ae. aegypti females infected with the wMel strain exhibited several significant differences compared with those infected with the wAlbB strain. Specifically, wMel-infected females laid significantly fewer eggs, ingested a lower amount of blood, had a reduced egg production rate, and exhibited a decreased Wolbachia density at a later age compared with mosquitoes infected with the wAlbB strain. Conversely, the wAlbB strain showed only mild negative effects when compared with Wolbachia-uninfected specimens. These differential effects on Ae. aegypti fitness following infection with either wMel or wAlbB may have important implications for the success of population replacement strategies in invading native Ae. aegypti populations in endemic settings. Further research is needed to better understand the underlying mechanisms responsible for these differences in fitness effects and their potential impact on the long-term efficacy of Wolbachia-based dengue control programs.IMPORTANCEThe transmission of arboviruses such as dengue, Zika, and chikungunya is on the rise globally. Among the most promising strategies to reduce arbovirus burden is the release of one out of two strains of Wolbachia-infected Aedes aegypti: wMel and wAlbB. One critical aspect of whether this approach will succeed involves the fitness cost of either Wolbachia strains on mosquito life history traits. For instance, we found that wMel-infected Ae. aegypti females laid significantly fewer eggs, ingested a lower amount of blood, had a reduced egg production rate, and exhibited a decreased Wolbachia density at a later age compared with mosquitoes infected with the wAlbB strain. Conversely, the wAlbB strain showed only mild negative effects when compared with Wolbachia-uninfected specimens. These differential effects on mosquito fitness following infection with either wMel or wAlbB may have important implications for the success of population replacement strategies in invading native Ae. aegypti populations.


Subject(s)
Aedes , Dengue , Wolbachia , Zika Virus Infection , Zika Virus , Animals , Female , Fertility , Dengue/prevention & control
16.
Multimedia | Multimedia Resources, MULTIMEDIA-SMS-SP | ID: multimedia-12925

ABSTRACT

Live para falar sobre ações de combate ao mosquito Aedes aegypti, transmissor da dengue. A transmissão contou com a presença de Melissa Palmieri, médica e assessora técnica da Vigilância Epidemiológica da Coordenaria de Vigilância em Saúde (Covisa).


Subject(s)
Dengue/prevention & control , Aedes , Primary Prevention
17.
Internet resource in Portuguese | LIS -Health Information Locator | ID: lis-49557

ABSTRACT

O aumento significativo de casos de dengue registrado nas primeiras semanas de 2024 no Brasil tem despertado a atenção de especialistas. O pesquisador e infectologista do Instituto Nacional de Infectologia (INI/Fiocruz), André Siqueira, destaca que, diante dessa realidade, é crucial abordar de maneira eficaz tanto o tratamento quanto a prevenção da doença.


Subject(s)
Research Personnel/standards , Dengue/prevention & control
18.
Internet resource in Portuguese | LIS -Health Information Locator | ID: lis-49558

ABSTRACT

Nesta semana, o Ministério da Saúde coordenou uma série de ações com foco no combate à dengue. Em agenda intensa, a ministra Nísia Trindade acompanhou a abertura da vacinação no Distrito Federal, cuja distribuição foi iniciada nesta quinta-feira (8) para os municípios prioritários. Ela também esteve presente durante inauguração do Centro de Operações de Emergência contra dengue e de novos polos de atendimento para a doença no Rio de Janeiro.


Subject(s)
Dengue/prevention & control
19.
Multimedia | Multimedia Resources | ID: multimedia-12921

ABSTRACT

O vídeo ressalta a importância dos cuidados, da mobilização e engajamento da população e do poder público para o combate ao Aedes aegypti, mosquito transmissor da dengue, Chikungunya e Zika.


Subject(s)
Dengue/prevention & control , Arbovirus Infections , Aedes
20.
Parasit Vectors ; 17(1): 91, 2024 Feb 27.
Article in English | MEDLINE | ID: mdl-38414050

ABSTRACT

BACKGROUND: Over the past two decades, dengue fever (DF) has emerged as a significant arboviral disease in Yunnan province, China, particularly in the China-Myanmar border area. Aedes aegypti, an invasive mosquito species, plays a crucial role in transmitting the dengue virus to the local population. Insecticide-based vector control has been the primary tool employed to combat DF, but the current susceptibility status of Ae. aegypti to commonly used insecticides is unknown. Assessment of Ae. aegypti resistance to pyrethroid insecticides and an understanding of the underlying mechanisms of this resistance in the China-Myanmar border region is of significant strategic importance for effectively controlling the DF epidemic in the area. METHODS: Aedes aegypti larvae collected from Ruili and Gengma counties in Yunnan Province were reared to adults in the laboratory and tested for susceptibility to three pyrethroid insecticides (3.20% permethrin, 0.08% lambda-cyhalothrin and 0.20% deltamethrin) by the standard WHO susceptibility bioassay. Genotyping of mutations in the knockdown gene (kdr), namely S989P, V1016G and F1534C, that are responsible for resistance to pyrethroid insecticides was performed using allele-specific PCR methods. A possible association between the observed resistant phenotype and mutations in the voltage-gated sodium channel gene (VGSC) was also studied. RESULTS: Aedes aegypti mosquitoes collected from the two counties and reared in the laboratory were resistant to all of the pyrethroids tested, with the exception of Ae. aegypti from Gengma County, which showed sensitivity to 0.20% deltamethrin. The mortality rate of Ae. aegypti from Ruili county exposed to 3.20% permethrin did not differ significantly from that of Ae. aegypti from Gengma County (χ2 = 0.311, P = 0.577). By contrast, the mortality rate of Ae. aegypti from Ruili County exposed to 0.08% lambda-cyhalothrin and 0.20% deltamethrin, respectively, was significantly different from that of Ae. aegypti from Gengma. There was no significant difference in the observed KDT50 of Ae. aegypti from the two counties to various insecticides. Four mutation types and 12 genotypes were detected at three kdr mutation sites. Based on results from all tested Ae. aegypti, the V1016G mutation was the most prevalent kdr mutation (100% prevalence), followed by the S989P mutation (81.6%) and the F1534C mutation (78.9%). The constituent ratio of VGSC gene mutation types was significantly different in Ae. aegypti mosquitoes from Ruili and those Gengma. The triple mutant S989P + V1016G + F1534C was observed in 274 Ae. aegypti mosquitoes (60.8%), with the most common genotype being SP + GG + FC (31.4%). The prevalence of the F1534C mutation was significantly higher in resistant Ae. aegypti from Ruili (odds ratio [OR] 7.43; 95% confidence interval [CI] 1.71-32.29; P = 0.01) and Gengma (OR 9.29; 95% CI 3.38-25.50; P = 0.00) counties than in susceptible Ae. aegypti when exposed to 3.20% permethrin and 0.08% lambda-cyhalothrin, respectively. No significant association was observed in the triple mutation genotypes with the Ae. aegypti population exposed to 3.20% permethrin and 0.20% deltamethrin resistance (P > 0.05), except for Ae. aegypti from Gengma County when exposed to 0.08% lambda-cyhalothrin (OR 2.86; 95% CI 1.20-6.81; P = 0.02). CONCLUSIONS: Aedes aegypti from Ruili and Gengma counties have developed resistance to various pyrethroid insecticides. The occurrence of multiple mutant sites in VGSC strongly correlated with the high levels of resistance to pyrethroids in the Ae. aegypti populations, highlighting the need for alternative strategies to manage the spread of resistance. A region-specific control strategy for dengue vectors needs to be implemented in the future based on the status of insecticide resistance and kdr mutations.


Subject(s)
Aedes , Dengue , Insecticides , Nitriles , Pyrethrins , Voltage-Gated Sodium Channels , Animals , Insecticides/pharmacology , Aedes/genetics , Permethrin , Myanmar , China/epidemiology , Pyrethrins/pharmacology , Mutation , Insecticide Resistance/genetics , Voltage-Gated Sodium Channels/genetics , Dengue/epidemiology , Dengue/prevention & control , Disease Outbreaks , Mosquito Vectors/genetics
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