Publications by authors named "Marcos Takashi Obara"

Gallery forests harbor mammals and sand flies that may be involved in the transmission of Leishmania spp. parasites. Characterizing the enzootic cycles of Leishmania spp.

View Article and Find Full Text PDF

is a species of public health interest because it is associated with the transmission of the bacteria that causes Brazilian Spotted Fever (BSF). The use of repellents on humans is a prophylactic measure widely used to provide protection against a series of arthropod vectors, including mosquitoes and ticks. However, in Brazil, the effectiveness of commercial repellents against is little known.

View Article and Find Full Text PDF
Article Synopsis
  • * A study from 2004 to 2020 analyzed funding trends, revealing that most of the budget (81.6%) focused on biomedical research, particularly for diseases like dengue and tuberculosis, while funding for other prevalent diseases remained low.
  • * The research highlighted stagnant funding levels, influenced by federal government changes, and emphasized the urgent need for sustainable investment in research for neglected tropical diseases to meet public health demands.
View Article and Find Full Text PDF
Article Synopsis
  • The Triatoma rubrovaria subcomplex includes several species that can transmit Trypanosoma cruzi, which causes Chagas disease.
  • The study analyzed the morphology, morphometric details, and genetic data of five species to understand their taxonomy and evolutionary relationships.
  • Findings revealed distinct morphological traits among the species, confirmed their monophyletic grouping, and supported the classification of these as important vectors in Southern Brazil.
View Article and Find Full Text PDF

Zika virus (ZIKV) infection has caused devastating consequences in Brazil as infections were associated with neurological complications in neonates. is the primary vector of ZIKV, and the evolution of insecticide resistance (IR) in this species can compromise control efforts. Although relative levels of phenotypic IR in mosquitoes can change considerably over time, its influence on vector competence for arboviruses is unclear.

View Article and Find Full Text PDF

Correct identification of triatomine bugs is crucial for Chagas disease surveillance, yet available taxonomic keys are outdated, incomplete, or both. Here we present TriatoDex, an Android app-based pictorial, annotated, polytomous key to the Triatominae. TriatoDex was developed using Android Studio and tested by 27 Brazilian users.

View Article and Find Full Text PDF
Article Synopsis
  • The study focused on examining the intraspecific variation of Triatoma costalimai, a species linked to Chagas disease, in Brazil and Bolivia.
  • The researchers analyzed both physical traits (like color patterns and wing shapes) and genetic data (16S mtDNA) across three Brazilian populations, comparing them to Bolivian populations and a closely related species.
  • Results indicated significant differences in coloration and wing morphology among Brazilian populations, along with distinct genetic separation from Bolivian T. costalimai and T. jatai, highlighting substantial variability within the species.
View Article and Find Full Text PDF

The classification of insecticide resistance in sand flies populations is based on concepts and methodologies used to characterize the susceptibility profile in mosquitoes. This can generate erroneous and subjective interpretations since they are biologically different organisms. In this context, the goal of this review is to analyze the works and/or articles that aimed at characterizing the susceptibility of sand flies and describing the methodological parameters, in order to improve future works to estimate more accurately the resistance of sand flies to insecticides.

View Article and Find Full Text PDF
Article Synopsis
  • The study monitors the effectiveness of malathion and pyriproxyfen in controlling the Ae. aegypti mosquito populations in Brazil, focusing on their susceptibility between 2017 and 2018.
  • The researchers conducted tests using diagnostic doses to assess resistance, finding that 55.3% of the populations were resistant to malathion, while alterations in susceptibility to pyriproxyfen were identified in 4.5% of the populations.
  • The results highlight the necessity of ongoing insecticide resistance monitoring to improve arbovirus control efforts across Brazil.
View Article and Find Full Text PDF

Although the chemical control against leishmaniasis began in 1953 in Brazil, little information is available on how this strategy has affected populations of phlebotomine sandflies in the field. The objective of this study was to analyze the susceptibility profile of four populations of phlebotomine sandflies to the insecticide alpha-cypermethrin. Sandflies collected in field in four Brazilian municipalities were evaluated using CDC bottles in different concentrations of alpha-cypermethrin.

View Article and Find Full Text PDF

Solid waste management is a challenge in developing countries. The Structural dump in Brasilia, Brazil, was the largest Latin American open-air dump until its closure in 2018. Thus, this study sought to investigate the prevalence of self-reported dengue, Zika and Chikungunya arbovirus infections in waste pickers who worked at the dumpsite and assess its association with the sanitary conditions in their residences and workplaces.

View Article and Find Full Text PDF

Introduction: In Brasilia, pyriproxyfen (PPF; 0.01 mg/L) has been used for the larval control of Aedes aegypti mosquitoes since 2016. Information on the susceptibility of Ae.

View Article and Find Full Text PDF

The insects of subfamily Triatominae exhibit many morphological features used for taxonomic identification. In some species, however, these features are very similar. The authors have proposed by first time the description of the structure referred as urotergite I process.

View Article and Find Full Text PDF

This article reports a list with 912 specimens of the subfamily Triatominae deposited in the Entomological Collection of the Faculty of Public Health of the University of Sao Paulo. The collection is composed of 1 holotype, 3 alotypes, 15 paralectotypes, 77 paratypes, distributed in 5 tribes and 12 genera: Tribus Alberprosenini: genus Alberprosenia Martinez & Carcavallo, 1977; Tribus Bolboderini: genus Microtriatoma Prosen & Martinez, 1952; Tribus Cavernicolini: genus Cavernicola Barber, 1937; Tribus Rhodnini: genus Psammolestes Bergroth, 1941; genus Rhodnius Stal, 1859; Tribus Triatomini: genus Dipetalogaster Usinger 1939; genus Eratyrus Stal 1859; genus Hermanlentia Jurberg & Galvão, 1997; genus Linshcosteus Distant, 1904; 1944; genus Panstrongylus Berg 1879; genus Paratriatoma Barber 1938; genus Triatoma Laporte 1833.

View Article and Find Full Text PDF

Introduction: Chagas disease surveillance requires current knowledge on synanthropic triatomines. We analyzed the occurrence and Trypanosoma cruzi infection rates of triatomine bugs in central Brazil, during 2012-2014.

Methods: Triatomines were collected inside or around houses, and T.

View Article and Find Full Text PDF

Vector-borne pathogens threaten human health worldwide. Despite their critical role in disease prevention, routine surveillance systems often rely on low-complexity pathogen detection tests of uncertain accuracy. In Chagas disease surveillance, optical microscopy (OM) is routinely used for detecting Trypanosoma cruzi in its vectors.

View Article and Find Full Text PDF

Background: Knowledge on synanthropic phlebotomines and their natural infection by Leishmania is necessary for the identification of potential areas for leishmaniasis occurrence.

Objective: To analyse the occurrence of Phlebotominae in gallery forests and household units (HUs) in the city of Palmas and to determine the rate of natural infection by trypanosomatids.

Methods: Gallery forests and adjacent household areas were sampled on July (dry season) and November (rainy season) in 2014.

View Article and Find Full Text PDF

Triatoma sordida has a widespread distribution in Argentina, Bolivia, Brazil, Paraguay, and Uruguay and is frequently found in peridomestic environments. We investigated size and shape variability of T. sordida wings across Brazil.

View Article and Find Full Text PDF

Introduction: This study describes the occurrence of trypanosomatids in phlebotomines in Brasília, Brazil.

Methods: Two hundred and ten females of 13 sand fly species were analyzed by polymerase chain reaction (PCR) using different molecular markers (D7 24Sα rRNA, kDNA, and ITS1) and sequencing.

Results: PCR revealed trypanosomatid-positive samples from Nyssomyia whitmani and Evandromyia evandroi, which were negative by kDNA and ITS1 Leishmania-specific PCRs.

View Article and Find Full Text PDF

Background: In general, there was a large reduction in the occurrence of cases of Chagas disease in the last decades in Brazil. However, despite all of these efforts, there have been various reports of persistent reinfestations of T. sordida in a large part of the state of Minas Gerais, for reasons still little investigated.

View Article and Find Full Text PDF
Article Synopsis
  • The study focuses on ongoing cases of Chagas disease in Brazil despite reduced transmission of the parasite Trypanosoma cruzi, emphasizing the need for effective prevention and control strategies.
  • Research analyzed data from 2275 municipalities between 2007 and 2011, assessing vulnerabilities to Chagas disease based on various indicators through a multi-criteria decision analysis (MCDA) method.
  • Findings indicate that the most vulnerable areas are primarily in northeastern Brazil, characterized by higher numbers of domiciliated triatomines and lower socioeconomic conditions, highlighting the importance of targeted surveillance and control efforts in these municipalities.
View Article and Find Full Text PDF
Article Synopsis
  • The study investigates the phylogenetic relationships within the Triatomini and Rhodniini tribes, which are key vectors for Chagas disease, and aims to provide clarity on their classification.
  • Utilizing six molecular markers, the researchers analyze various genera and species groups, revealing that certain Rhodnius species are more closely related than previously thought, and highlighting geographical distribution patterns in the Triatoma genus.
  • The authors suggest reclassifying some complexes as separate genera and emphasize the need for comprehensive morphological studies to properly categorize these insects.
View Article and Find Full Text PDF