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Aedes aegypti and Culex quinquefasciatus mosquitoes are vectors of different arboviruses that cause a large burden of disease in humans worldwide. A key step towards reducing the impact of arboviruses on humans can be achieved through integrated mosquito surveillance and control approaches. We carried out an integrated approach of mosquito surveillance and control actions to reduce populations of these insects along with a viral surveillance in a neighborhood of Recife (Northeastern Brazil) with high mosquito densities and arbovirus transmission. The actions were carried out in 40 different houses in the Nova Descoberta neighborhood. The area was divided into two groups, the control group using tools to monitor the mosquito density (1 OVT; 1 Double BR-ovt; monthly capture of alates) and the experimental group with control actions using surveillance tools in an intensified way (2 OVTs; 2 Double BR-ovts; fortnightly capture of alates; toxic baits). We evaluated the study's impact on the mosquito density via the Egg Density (ED) and Adult Density (AD) over a period of 12 cycles of 28 days each. The collected adult mosquitoes were processed via RT-qPCR for DENV, CHIKV and ZIKV and, subsequently, the Minimum Infection Rate (MIR) was calculated. After 12 cycles, we observed a 91% and 99% reduction in Aedes ED and AD in the monitored properties, as well as a 76% reduction in the AD of Cx. quinquefasciatus in the same properties. Moreover, we detected circulating arboviruses (DENV and ZIKV) in 19.52% of captured adult mosquitoes. We show that enhancing entomological surveillance tools can aid in the early detection of possible risk areas based on vector mosquito population numbers. Additionally, the detection of important arboviruses such as ZIKV and DENV raises awareness and allows for a better selection of risk areas and silent virus spread. It offers supplementary information for guiding emergency mosquito control measures in the target area. The goal is to minimize human-vector interactions and, subsequently, to lower the risk of transmitting circulating arboviruses.
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We aimed to determine how the degree of urbanization in a Neotropical city influences Aedes aegypti (L.), a pantropical vector of urban yellow fever, dengue, Zika and Chikungunia, via other mosquito species, whether they are competitors or predators, native to the area or invasive. We conducted experiments twice a month during one year in the city of Kourou, French Guiana, on three sites characterized by increasing percentages of imperviousness (i.e., 0.65%, 33.80% and 86.60%). These sites were located in a ≈5 ha forest fragment, a residential area with gardens, and in the older part of the city, respectively, and correspond to slightly, moderately and highly urbanized sites. There, we monitored twice a month during one year a total of 108 mosquito communities inhabiting four types of containers (i.e., a tank bromeliad, dry stumps of bamboo, ovitraps and car tires) installed in a random block design. In the tanks of the bromeliad, likely due to the acidity of the water, the immatures of native mosquito species prevailed, particularly Wyeomyia pertinans (Williston) in the slightly urbanized site. The general pattern was very similar in the three other types of containers where Limatus durhamii Théobald dominated in the slightly urbanized site, so that the abundance of Ae. aegypti immatures was low compared to those of native species. Yet, Ae. aegypti strongly dominated in the two more urbanized sites. These findings open up perspectives for vector management, including the conservation and/or the augmentation of natural enemies through modifications to landscape features.
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Aedes , Infecção por Zika virus , Zika virus , Animais , Urbanização , Água , Mosquitos Vetores , CidadesRESUMO
BACKGROUND: The mosquito Aedes aegypti is an urban vector of dengue and other arboviruses. During epidemics of these viruses, pyrethroid insecticides are used for the control of adult mosquitoes. The worldwide resistance of Ae. aegypti to these insecticides is a cause of failure of vector control campaigns. The primary target of pyrethroids is the voltage-gated sodium channel. Point mutations in the gene coding for this channel, called knockdown resistance (kdr) mutations, are associated with pyrethroid resistance. Two kdr mutations, V1016I and F1534C, have increased in frequency in natural populations of Ae. aegypti in the Americas during the last decade. Their association with pyrethroid resistance has been largely demonstrated in field populations throughout the Americas, and in in vitro assays. Diagnostics for kdr polymorphism allow early detection of the spread of insecticide resistance, which is critical for timely decisions on vector management. Given the importance of resistance management, high-throughput methods for kdr genotyping are valuable tools as they can be used for resistance monitoring programs. These methods should be cost-effective, to allow regional-scale surveys. Despite the extensive presence of Ae. aegypti and incidence of dengue in Argentina, the presence, abundance, and distribution of kdr mutations in populations of this mosquito have yet to be reported for the country. METHODS: Aedes aegypti samples were collected as immature stages or adults from Buenos Aires Metropolitan Area and northern localities of Tartagal (Salta Province) and Calilegua (Jujuy Province). Immature stages were maintained in the laboratory until they developed into adults. A high-resolution melting assay, based on an analysis of melting temperatures, was developed for the simultaneous genotyping of V1016I and F1534C kdr mutations. We used this method to infer the presence and frequencies of kdr alleles in 11 wild populations from Argentina. RESULTS: We demonstrated the presence of kdr mutations in Ae. aegypti in Argentina in regions where this species is under different selection pressures due to the use of pyrethroids. The populations under analysis are located in geographically distant regions of the species' distribution in Argentina: the northern provinces of Salta and Jujuy and the Buenos Aires Metropolitan Area. Higher frequencies of resistant-associated alleles were detected in the northern region. We report a multiplex high-throughput assay based on a high-resolution melting polymerase chain reaction method for the simultaneous genotyping of V1016I and F1534C kdr mutations. This assay was shown to be cost-effective, and thus provides an interesting molecular tool for kdr genotyping in A. aegypti control campaigns. CONCLUSIONS: We report, to the best of our knowledge for the first time, the presence of kdr mutations in populations of Ae. aegypti from geographically distant locations of Argentina that differ with respect to their epidemiological situation and history of mosquito control. We have developed a high-throughput method for the genotyping of kdr mutations in Ae. aegypti from the Americas. Given its affordability and short running time, this method can be used in control campaigns to monitor the presence and spread of kdr alleles. The information provided here is relevant for the rational design of control strategies in the context of integrated vector management.
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Aedes , Dengue , Inseticidas , Piretrinas , Animais , Inseticidas/farmacologia , Aedes/genética , Argentina , Mosquitos Vetores/genética , Mutação , Resistência a Inseticidas/genética , Reação em Cadeia da PolimeraseRESUMO
This document highlights the major achievement of the Ministry of Health for the period 2020-2021. Contains information about Health System Strengthening Programme (HSSP), mental health, National HIV/STI Programme, Integrated Vector Management Programme, non-communicable diseases, Jamaica Moves, Programme for the Reduction Of Matenal and Child Mortality and Enhancing Healthcare Services Delivery Project.
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Sistemas de Saúde , Saúde Pública , Controle de Vetores de Doenças , Doenças não TransmissíveisRESUMO
In American countries, simultaneously with the coronavirus disease 2019 (COVID-19) pandemic, epidemics caused by different arboviruses (dengue, chikungunya and Zika viruses) are occurring. In Mexico, several of the strategies to control the Aedes aegypti mosquito, which transmits arboviruses, involve the interaction of health personnel with the community. Due to the COVID-19 pandemic, social distancing and home confinement measures have been implemented. To obey these measures and avoid the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission, the National Center for Preventive Programs and Disease Control (CENAPRECE) has presented the vector control strategy in the scenario of simultaneous dengue and COVID-19 transmission in Mexico. In this work, we mention the routine comprehensive mosquito control measures and describe the adaptations that have been made. Furthermore, we discuss the relevance of medical personnel training and supervision, especially focusing on the similarity of symptoms between both pathologies.
En países americanos, simultáneas a la pandemia de enfermedad por coronavirus 2019 (COVID-19) se están dando epidemias ocasionadas por diferentes arbovirus (del dengue, chikunguña y virus del Zika). En México, varias de las estrategias para control del mosquito Aedes aegypti, transmisor de arbovirus, involucran la interacción del personal salubrista y los moradores. Debido a la pandemia de COVID-19 se han implementado medidas de distanciamiento social y resguardo domiciliario. Para respetar estas medidas y evitar riesgo de contagio por coronavirus 2 del síndrome respiratorio agudo grave (SARS-CoV-2), el Centro Nacional de Programas Preventivos y Control de Enfermedades (CENAPRECE) ha presentado la estrategia de control de vectores en el escenario de transmisión simultánea por dengue y COVID-19 en México. En este trabajo mencionamos las medidas habituales de manejo integral de mosquito y mencionamos las adaptaciones realizadas. De igual forma, discutimos la relevancia de la capacitación y la supervisión al personal médico, esto debido a la similitud entre la sintomatología entre ambas patologías.
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Aedes/virologia , Infecções por Arbovirus/epidemiologia , COVID-19/epidemiologia , Monitoramento Epidemiológico , Controle de Mosquitos/métodos , Pandemias , Animais , Infecções por Arbovirus/prevenção & controle , COVID-19/prevenção & controle , Febre de Chikungunya/epidemiologia , Febre de Chikungunya/prevenção & controle , Dengue/epidemiologia , Dengue/prevenção & controle , Promoção da Saúde , Humanos , Disseminação de Informação , Distanciamento Físico , Infecção por Zika virus/epidemiologiaRESUMO
The adoption of novel integrated vector management (IVM) strategies requires proof-of-concept demonstrations. To implement a community-based intervention, for the control of vectors of Chagas disease in Guatemala, we engaged all relevant stakeholder groups. Based on this and previous experiences of the authors on engaged research and community-based interventions, several key factors can help facilitate effective integration of stakeholders in support of area-wide integrated vector management (AW - IVM) programmes. First and foremost, the diversity of stakeholders needs to be engaged early-on in the participatory action research and implementation processes, to provide ownership and contribute ideas on how to design and implement an intervention. Another important component, situational analysis regarding current pest control policies, practices and relevant stakeholders, is generated through interviews with key informants, at both national and local levels (governmental and non-governmental organizations); it can facilitate the joint identification of strengths, weaknesses, opportunities and threats regarding current pest control strategies and proposing solutions through an AW-IVM approach. In addition, successful AW - IVM can result from identifying locally relevant strategies to implement the proof-of-concept demonstrative project. Further, it is critical to maintain constant communication with the local and national leaders, involving them throughout the implementation and evaluation processes. Flexibility should also be built into the project to allow for community-driven changes in the strategy, through a cyclical joint reflective process. Periodic feedback of project development needs to be scheduled with key stakeholders to maintain rapport. Finally, the results of the evaluation should be shared and discussed with stakeholders to ensure long-term sustainability of the programme, intervention, or project. Here we present the citizen engagement procedures used to integrate community members, health officials, and non-governmental organization staff for Chagas disease control in a region of Guatemala. We demonstrate how these methods can be applied to support AW-IVM programmes, so that communities and authorities are actively involved in the development and implementation of a jointly agreed intervention. In 2012, we developed the IVM intervention in an area of Guatemala with persistentTriatoma dimidiata (Latreille) infestation that is associated with the presence of infected rodents (rats and mice), that act as reservoirs of the Trypanosoma cruzi Chagas parasites inside the households. Nine control communities received only the Ministry of Health insecticide application against the vector and nine intervention communities participated in the AW-IVM intervention. The intervention included a programme for rodent control by the community members, together with education about the risk factors for vector infestation, and insecticide application by the Ministry of Health. Entomological evaluations in 2014 and 2015 showed that vector infestation remained significantly lower in both intervention and control communities. In 2015, we found that there was a higher acceptance of vector surveillance activities in the intervention communities compared to control communities, suggesting that participatory activities increase programme sustainability. Finally, we found that there was a significant increase over time in the number of households with infected vectors in the control group, whereas there was no significant increase in the communities that participated in the programme. Thus, an AW-IVM programme including simultaneous rodent and vector control could reduce the risk of Chagas infection in communities with persistent vector infestation.
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Rhodnius , Triatoma , Trypanosoma , América Central , Doença de Chagas , Participação Social , InseticidasRESUMO
The Sterile Insect Technique (SIT) is a pest control method where large numbers of sterile males are released to induce sterility in wild populations. Since a successful SIT application depends on the released sterile males being competitive with wild males, standard quality control tests are a necessary component of any SIT program. Flight ability (ability to fly out from a device) is a reliable indicator of insect quality. Based on previous studies, we developed four new tubular devices constructed with locally available materials to explore their potential as flight test devices for Aedes aegypti (L.) mass-reared males. Males were allowed to fly upwards through a vertical tube, the ones that flew out were considered successful. The effect of male age (0 to 21 d old), test time interval (30 min to 24 h), and the design of the device (40 and 80 cm height and 2 and 3.5 cm diameter) were evaluated. Our devices determined differences in the flight ability of Ae. aegypti males of different ages. During the first minutes, more old males escaped than young males in three out of four types of devices. However, young males reached higher rates of escape in all cases after 24 h. For standard quality control tests, we recommend testing 2- to 3-d-old sexually mature males in the high and narrow device (80 × 2 cm). Further observations for time intervals between 1 and 5 h might be performed to decide the shortest and more representative interval to use.
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Aedes/fisiologia , Voo Animal , Controle de Mosquitos/métodos , Controle Biológico de Vetores/métodos , Comportamento Sexual Animal , Fatores Etários , Animais , Masculino , Controle de Mosquitos/instrumentação , Controle Biológico de Vetores/instrumentação , ReproduçãoRESUMO
BACKGROUND: Malaria is a public health problem in the Brazilian Amazon region. In integrated vector management for malaria (anopheline) control, indoor residual spraying (IRS) represents one of the main tools in the basic strategy applied in the Amazonian states. It is essential to understand the residual efficacy of insecticides on different surfaces to determine spray cycles, ensure their rational use, and prevent wastage. This study aimed to evaluate the residual efficacy of six insecticide formulations used in the National Malaria Control Programme on four different types of walls in a field simulation at a "test house". METHODS: The tests were performed as a field-simulating evaluation at a "test house" built in the municipality of Macapá. Six insecticide formulations comprising four pyrethroids, a carbamate, and an organophosphate were used, and evaluated when applied on different wall surfaces: painted wood, unpainted wood, plastered cement, and unplastered cement. The insecticides were applied to the interior walls of the "test house" by a trained technician. RESULTS: In the bioassays performed with pyrethroids, deltamethrin water-dispersible granules (WG) performed particularly well, presenting residual bioefficacy of 8 months on both wood surfaces after the IRS, whereas alpha-cypermethrin suspension concentrate (SC) and etofenprox wettable powder (WP) demonstrated residual bioefficacy of 4 months on at least one of the wood surfaces; however, the pyrethroid lambda-cyhalothrin WP showed a low residual bioefficacy (< 3 months) on all tested surfaces, demonstrating its inefficiency for areas with a long transmission cycle of malaria. For the carbamate-bendiocarb WP, residual bioefficacy for 3 months was achieved only on wood surfaces. In general, the organophosphate pirimifos-methyl capsule suspension (CS) demonstrated the best result, with a mortality rate < 80% over a period of 6 months on all surfaces tested. CONCLUSION: Insecticide efficiency varies among different types of surface; therefore, a "test house" is a valuable evaluation tool. This work highlights the usefulness of associating the residual efficacy of insecticides on the surfaces commonly found in houses in endemic areas, together with knowledge about the transmission cycle duration of the transmission cycle and the insecticide susceptibility of the vector. This association helps in the decision-making for the malaria control intervention regarding.
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Anopheles , Inseticidas , Malária/prevenção & controle , Controle de Mosquitos , Mosquitos Vetores , Animais , Brasil , HabitaçãoRESUMO
Chagas disease prevention remains mostly based on triatomine vector control to reduce or eliminate house infestation with these bugs. The level of adaptation of triatomines to human housing is a key part of vector competence and needs to be precisely evaluated to allow for the design of effective vector control strategies. In this review, we examine how the domiciliation/intrusion level of different triatomine species/populations has been defined and measured and discuss how these concepts may be improved for a better understanding of their ecology and evolution, as well as for the design of more effective control strategies against a large variety of triatomine species. We suggest that a major limitation of current criteria for classifying triatomines into sylvatic, intrusive, domiciliary and domestic species is that these are essentially qualitative and do not rely on quantitative variables measuring population sustainability and fitness in their different habitats. However, such assessments may be derived from further analysis and modelling of field data. Such approaches can shed new light on the domiciliation process of triatomines and may represent a key tool for decision-making and the design of vector control interventions.
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Animais , Humanos , Controle de Insetos/métodos , Insetos Vetores/classificação , Triatominae/classificação , Doença de Chagas/transmissão , Ecossistema , Habitação , Insetos Vetores/fisiologia , Triatominae/fisiologiaRESUMO
This article provides an overview of three research projects which designed and implemented innovative interventions for Chagas disease vector control in Bolivia, Guatemala and Mexico. The research initiative was based on sound principles of community-based ecosystem management (ecohealth), integrated vector management, and interdisciplinary analysis. The initial situational analysis achieved a better understanding of ecological, biological and social determinants of domestic infestation. The key factors identified included: housing quality; type of peridomestic habitats; presence and abundance of domestic dogs, chickens and synanthropic rodents; proximity to public lights; location in the periphery of the village. In Bolivia, plastering of mud walls with appropriate local materials and regular cleaning of beds and of clothes next to the walls, substantially decreased domestic infestation and abundance of the insect vector Triatoma infestans. The Guatemalan project revealed close links between house infestation by rodents and Triatoma dimidiata, and vector infection with Trypanosoma cruzi. A novel community-operated rodent control program significantly reduced rodent infestation and bug infection. In Mexico, large-scale implementation of window screens translated into promising reductions in domestic infestation. A multi-pronged approach including community mobilisation and empowerment, intersectoral cooperation and adhesion to integrated vector management principles may be the key to sustainable vector and disease control in the affected regions.
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Doença de Chagas/prevenção & controle , Controle de Doenças Transmissíveis/organização & administração , Doenças do Cão/parasitologia , Triatoma/patogenicidade , Trypanosoma cruzi/patogenicidade , Animais , Doença de Chagas/transmissão , Galinhas/parasitologia , Serviços de Saúde Comunitária , Reservatórios de Doenças , Doenças do Cão/epidemiologia , Doenças do Cão/prevenção & controle , Cães , Ecossistema , Planejamento Ambiental , Exposição Ambiental , Conhecimentos, Atitudes e Prática em Saúde , Habitação/normas , Humanos , Insetos Vetores/parasitologia , América Latina/epidemiologia , Prevalência , Fatores de Risco , Roedores/parasitologia , Estações do Ano , Fatores SocioeconômicosRESUMO
BACKGROUND: This study intended to implement a novel intervention strategy, in Brazil, using an ecohealth approach and analyse its effectiveness and costs in reducing Aedes aegypti vector density as well as its acceptance, feasibility and sustainability. The intervention was conducted from 2012 to 2013 in the municipality of Fortaleza, northeast Brazil. METHODOLOGY: A cluster randomized controlled trial was designed by comparing ten intervention clusters with ten control clusters where routine vector control activities were conducted. The intervention included: community workshops; community involvement in clean-up campaigns; covering the elevated containers and in-house rubbish disposal without larviciding; mobilization of schoolchildren and senior inhabitants; and distribution of information, education and communication (IEC) materials in the community. RESULTS: Differences in terms of social participation, commitment and leadership were present in the clusters. The results showed the effectiveness of the intervention package in comparison with the routine control programme. Differences regarding the costs of the intervention were reasonable and could be adopted by public health services. CONCLUSIONS: Embedding social participation and environmental management for improved dengue vector control was feasible and significantly reduced vector densities. Such a participatory ecohealth approach offers a promising alternative to routine vector control measures.
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Serviços de Saúde Comunitária/organização & administração , Dengue/prevenção & controle , Reservatórios de Doenças/parasitologia , Controle de Mosquitos/organização & administração , Aedes/parasitologia , Animais , Atitude Frente a Saúde , Brasil/epidemiologia , Análise por Conglomerados , Ecossistema , Entomologia , Estudos de Viabilidade , Conhecimentos, Atitudes e Prática em Saúde , Promoção da Saúde/organização & administração , Habitação , Humanos , Insetos Vetores/patogenicidade , Participação SocialRESUMO
Neste artigo, revisei o estado do dicloro-difenil-tricloroetano (DDT) utilizado no controle de doenças causadas por vetores, e seus benefícios e riscos em relação às alternativas disponíveis. Dados atuais sobre o uso de DDT foram obtidos através de questionários e relatórios, assim como uma busca Scopus para resgatar artigos publicados. Quase 14 países utilizam DDT para controle de doenças, e diversos outros o estão reintroduzindo. A preocupação sobre o uso contínuo de DDT é abastecida por relatórios recentes dos altos níveis de exposição humana associada com a pulverização em recintos fechados, acumulando evidências sobre efeitos crônicos a saúde. Existem sinais de que mais vetores da malária estão se tornando resistentes à ação tóxica do DDT. Métodos químicos efetivos estão disponíveis como alternativas imediatas ao DDT, mas o desenvolvimento da resistência está diminuindo a eficácia das ferramentas de insetização. Métodos não químicos são potencialmente importantes, mas sua efetividade no programa necessita de estudos urgentes. O controle integrado de vetores fornece uma estrutura para o desenvolvimento e a implementação de tecnologias e estratégias efetivas como alternativas sustentáveis à dependência ao DDT.
In this article I reviewed the status of dichlorodiphenyltrichloroethane (DDT), used for disease vector control, and its benefits and risks in relation to the available alternatives. Contemporary data on DDT use were obtained from questionnaires and reports as well as a Scopus search to retrieve published articles. Nearly 14 countries use DDT for disease control, and several others are reintroducing DDT. Concerns about the continued use of DDT are fueled by recent reports of high levels of human exposure associated with indoor spraying amid accumulating evidence on chronic health effects. There are signs that more malaria vectors are becoming resistant to the toxic action of DDT. Effective chemical methods are available as immediate alternatives to DDT, but the development of resistance is undermining the efficacy of insecticidal tools. Nonchemical methods are potentially important, but their effectiveness at program level needs urgent study. To reduce reliance on DDT, support is needed for integrated and multipartner strategies of vector control. Integrated vector management provides a framework for developing and implementing effective technologies and strategies as sustainable alternatives to reliance on DDT.