Publications by authors named "Rafael Maciel de Freitas"

Article Synopsis
  • Dengue fever, spread by Aedes mosquitoes, is a major public health issue in tropical regions, requiring effective surveillance to inform interventions like vector control and public education.
  • A newly developed surveillance system in Foz do Iguaçu, Brazil, tracks dengue transmission using data collected by over 100 health agents from November 2022 to April 2024.
  • The implementation of the Vigilância Integrada com Tecnologia (VITEC) system improved the identification of dengue transmission risks, allowing public health managers to optimize targeted interventions in high-risk areas.
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Background: The effectiveness of dengue control interventions depends on an effective integrated surveillance system that involves analysis of multiple variables associated with the natural history and transmission dynamics of this arbovirus. Entomological indicators associated with other biotic and abiotic parameters can assertively characterize the spatiotemporal trends related to dengue transmission risk. However, the unpredictability of the non-linear nature of the data, as well as the uncertainty and subjectivity inherent in biological data are often neglected in conventional models.

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Article Synopsis
  • The rise in mosquito-borne diseases like dengue and Zika poses a significant public health challenge, prompting the need for better surveillance systems.
  • A study used an optical sensor with mosquito traps in Brazil, capturing 9,151 insect flights over a year, identifying specific mosquito species, Aedes aegypti and Culex quinquefasciatus, with impressive accuracy rates.
  • The automated sensor demonstrated high reliability in distinguishing between target mosquito types and sexes, even adapting European classification models successfully for Brazilian populations.
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The mosquito is distributed worldwide and is recognized as the primary vector for dengue in numerous countries. To investigate whether the fitness cost of a single DENV-1 isolate varies among populations, we selected four populations from distinct localities: Australia (AUS), Brazil (BRA), Pakistan (PAK), and Peru (PER). Utilizing simple methodologies, we concurrently assessed survival rates and fecundity.

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Article Synopsis
  • Dengue has become widespread globally, primarily transmitted by the Aedes aegypti mosquito, especially in urban areas, with traditional control methods proving ineffective.
  • A study conducted during the SARS-CoV-2 pandemic examined the relationship between dengue transmission in children and mosquito density, revealing a seasonal pattern with most cases occurring in warmer months.
  • Findings indicated a strong spatial structure in dengue cases, a surprising negative correlation between dengue transmission and adult mosquito density, and suggested that factors beyond human mobility could influence dengue dynamics.
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Two strains, Mel and AlbB, have been transinfected into 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 strains Mel and AlbB on fitness in a common genetic background.

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Female mosquitoes of the genus Sabethes Robineau-Desvoidy, 1827 are implicated in the transmission of several arboviruses, including yellow fever virus. Here, we present an illustrated species identification key for females of the genus Sabethes recorded in Brazil, except Sa. nitidus Theobald, 1901 and Sa.

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Objectives: Arboviruses, such as dengue (DENV), zika (ZIKV), and chikungunya (CHIKV), constitute a growing urban public health threat. Focusing on Aedes aegypti mosquitoes, their primary vectors, is crucial for mitigation. While traditional immature-stage mosquito surveillance has limitations, capturing adult mosquitoes through traps yields more accurate data on disease transmission.

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Several countries have been using deployments to replace highly competent native populations with -carrying mosquitoes with lower susceptibility to arboviruses such as dengue, Zika, and chikungunya. In Rio de Janeiro, deployments started in 2015 and still present a moderate introgression with a modest reduction in dengue cases in humans (38%). Here, we evaluated the vector competence of wild-type and Mel-infected with a Brazilian genetic background to investigate whether virus leakage could contribute to the observed outcomes in Brazil.

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Background: Understanding aspects related to the physiology and capacity of vectors is essential for effectively controlling vector-borne diseases. The sand fly Lutzomyia longipalpis has great importance in medical entomology for disseminating Leishmania parasites, the causative agent of Leishmaniasis, one of the main neglected diseases listed by the World Health Organization (WHO). In this respect, it is necessary to evaluate the transmission potential of this species and the success of vector control interventions.

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Background: The mosquito microbiota impacts different parameters in host biology, such as development, metabolism, immune response and vector competence to pathogens. As the environment is an important source of acquisition of host associate microbes, we described the microbiota and the vector competence to Zika virus (ZIKV) of from three areas with distinct landscapes.

Methods: Adult females were collected during two different seasons, while eggs were used to rear F1 colonies.

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Vector control is still the recommended approach to avoid arbovirus outbreaks. Herein, we investigate oviposition preferences of Aedes aegypti (Diptera: Culicidae) females under a semi-field structure Rio de Janeiro, Brazil. For that, in Experiment 1, we used two settings: 'Single items', which included as containers drain, beer bottle, bucket, car tyre, water tank, and a potted Peace Lily (Spathiphyllum wallisii) in a saucer with water, or 'Multiple containers', as an urban simulation, in which one drain, two additional beer bottles, and an extra plant pot saucer were added.

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(1) Background: The deployment of the bacterium to reduce arbovirus transmission is ongoing in several countries worldwide. When -carrying are released and established in the field, females may feed on dengue-infected hosts. The effects of simultaneous exposure on life-history traits of to wMel strain and dengue-1 virus DENV-1 remain unclear.

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Article Synopsis
  • Aedes aegypti females influence the bacterial communities in their breeding sites to enhance the development and fitness of their offspring.
  • Research shows that the presence of ovipositing females leads to decreased microbial diversity and shifts in bacterial composition, which could benefit larval growth.
  • One specific bacterial taxon, Elizabethkingia, has been identified as positively affecting mosquito larvae, supporting the idea that female mosquitoes actively shape their breeding environment.
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Article Synopsis
  • A field entomologist is struggling with a failing mosquito control project.
  • A chance encounter sparks a new idea or realization.
  • This moment of insight leads him to a breakthrough in tackling the mosquito problem.
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To eliminate malaria, scalable tools that are rapid, affordable, and can detect patients with low parasitemia are required. Non-invasive diagnostic tools that are rapid, reagent-free, and affordable would also provide a justifiable platform for testing malaria in asymptomatic patients. However, non-invasive surveillance techniques for malaria remain a diagnostic gap.

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The transmission of dengue (DENV) and Zika (ZIKV) has been continuously increasing worldwide. An efficient arbovirus surveillance system is critical to designing early-warning systems to increase preparedness of future outbreaks in endemic countries. The Near Infrared Spectroscopy (NIRS) is a promising high throughput technique to detect arbovirus infection in with remarkable advantages such as cost and time effectiveness, reagent-free, and non-invasive nature over existing molecular tools for similar purposes, enabling timely decision making through rapid detection of potential disease.

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Currently, DENV transmitted primarily by affects approximately one in three people annually. The spatio-temporal heterogeneity of vector infestation and the intensity of arbovirus transmission require surveillance capable of predicting an outbreak. In this work, we used data from 4 years of reported dengue cases and entomological indicators of adult collected from approximately 3500 traps installed in the city of Foz do Iguaçu, Brazil, to evaluate the spatial and temporal association between vector infestation and the occurrence of dengue cases.

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Arboviruses transmitted by in urban environments have spread rapidly worldwide, causing great impacts on public health. The development of reliable and timely alert signals is among the most important steps in designing accurate surveillance systems for vector-borne diseases. In July and September 2017, we conducted a pilot study to improve an existing integrated surveillance system by using entomo-virological surveillance to prioritize areas to conduct active searches for individuals with arbovirus infection symptoms.

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Background: Chagas disease (American trypanosomiasis) is an important neglected tropical illness, which has the flagellate protozoan Trypanosoma cruzi as etiological agent and blood-feeding insects of the Triatominae subfamily as vectors. Despite its importance for disease epidemiology, field studies targeting microgeographic dispersal of triatomines in endemic areas are rare. The ability wingless nymphs have to move (crawl) within peridomestic settings is a key component regarding the design and development of rational control strategies.

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Zika is a vector-borne disease caused by an arbovirus (ZIKV) and overwhelmingly transmitted by . This disease is linked to adverse fetal outcomes, mostly microcephaly in newborns, and other clinical aspects such as acute febrile illness and neurologic complications, for example, Guillain-Barré syndrome. One of the most promising strategies to mitigate arbovirus transmission involves releasing mosquitoes carrying the maternally inherited endosymbiont bacteria .

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Arbovirus epidemiology lacks efficient and timely surveillance systems with accurate outbreak alert signals. We devised a citywide integrated surveillance system combining entomologic, epidemiologic, and entomo-virologic data gathered during 2017-2020 in Foz do Iguaçu, Brazil. We installed 3,476 adult mosquito traps across the city and inspected traps every 2 months.

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Article Synopsis
  • Chagas disease, caused by the Trypanosoma cruzi parasite, affects an estimated 70 million people, and traditional detection methods can be low in sensitivity or expensive in endemic areas.
  • A study evaluated the accuracy of Near Infrared Spectroscopy (NIRS) as a reagent-free, rapid, and non-invasive technique for detecting T. cruzi infection in the body parts and excreta of the Triatoma infestans insect, achieving 100% accuracy for various samples.
  • This research represents the first use of NIRS for this purpose, and future studies aim to test its effectiveness on field-collected triatomines.
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